Neuro Notes 63 Pages

8/2/2019 Neuro Notes 63 Pages

1/63

Spinal cord1.

Medullaa.

Ponsb.

Midbrainc.

Brain stem2.

Cerebellum3.

Diencephalon (Thalamus & Hypothalamus)4.Cerebrum (Cortex)5.

Neuraxis/Neural axis (from bottom to top)

Neural AxisMay-12-10

9:00 AM


2/63

Responsible for simple reflex motor actions(ie: removing hand from hot plate)

Spinal cord is 45 cm long inside vertebral column (60-75 cm)

Cont'n of brain stem (medulla oblongata) at the level ofC1 (atlas) thru the for magnum

Adults: L1/L2 intervertebral disc (ie: occupies upper 2/3 of vertebral column due to

the differential growth of the column)

o

Infants: L3o

In utero = entire length of the vertebral columno

Spinal cord ends at

Conus medullaris: the lower edge of the spinal cord (from L1/L2 for adults and L3 in infants)

Rootletsattach to the spinal cordo

Posterior (Dorsal) root --> Dorsal root (Spinal) gangliono

Anterior (Ventral) rooto

Mixed Nerveo

Posterior (Dorsal) ramuso

Anterior (Ventral) ramuso

Neuromere = region of the spinal cord that gives off a pair of spinal nerves (31 segments)

Spinal segment: C8, T12, L5, S5, Cx1 (total = 31)

Vertebrae: C7, T12, L5, S5, Cx3 (the coccygeal vertebrae are fused hence total = 30; unfused

total = 33)

Segmental (regional) anesthesia in epidural space at specific dermatome

Laminectomy:removal of lamina of vertebra to release pressure on spinal cord from tumors

C7 end of the necko

L4 - at the level of the iliac cresto

Bony vertebral prominences:

Cervical spine + 1 (ie: 5th spinal segment is opposite to 4thcervical spine)o

Upper thoracic (T6) + 2 (ie: 5th upper thoracic segment is across 3rd T3 spine)o

Lower thoracic (T7-T10) + 3o

T11 + 4 (L3 spinal segment)o

T12 + 6 (S1 spinal segment)o

After L1 add requisite spinal spineso

Rules for determining location of the spinal segment (go down!!):

Cervical enlargement (C5-T1) --> to accommodate the brachial plexuso

Lumbar enlargement (L1-L4) --> to accommodate the lumbo-sacral plexuso

2 enlargements of the spinal cord (to accommodate increased number of neurons)

Anterior median fissure (AMF)o

Anterolateral sulcus (ALS)o

Posterior median sulcus (PMS)o

Posteriorlateral sulcus (PLS)o

Longitudinal fissures:

The spinal cord has been divided into two equal halves by the AMF and the two halves are

connected by the white commissure and grey commissure (nerve fibres)

The periosteum of the cranium is replaced by the pericranium (5 th layer of scalp)o

Outer endosteal layer

Inner meningeal layer --> forms tentorium cerebri, tentorium cerebelli, etc.

Cerebral Dura Mater: 2 layers separated by dural venous sinuseso

NO epidural space bc outer endosteal is part of pericranium (potential space)o

Epidural hematoma needs to be resolved within 24 hrs otherwise death will resulto

Cerebral Dura Mater covers the brain

Spinal Dura Mater (only one layer) & considerable epidural space

Arachnoid mater

Spinal Pia mater

Meninges of the spinal cord

Spinal Cord (Spina Medullaris)May-13-10

9:00 AM


3/63

Extends from the margin of the foramen magnum to the S2 vertebra

Fato

Radicals of veins

Caval system of veins

Azygous system of veins (not paired with arteriesslow )

Thyroid gland veins

Prostrate veins

Breast veins

Lymphatics

Venous systemArterial system

Organ to organ

4 possible routes of metastasis (in order):

Due to the vertebral venous plexus, there can be metastasis from different

organs to the spinal cord, hence causing compression of the spinal cord

Vertebral venous plexus of Baton (Valveless --> hence blood can flow in both

directions): Normal changes in the abdominal or intrathoracic pressure (-3 to -4

mmHg) does not alter flow in these veins howevercoughing, sneezingdoes

Communicates with the:

o

Roots of the spinal nerve (hence segmental/regional/epidural anesthesia can be

achieved via the epidural space)

o

Epidural space

Most common procedure: Childbirtho

Through the sacral hiatuso

Epidural anesthesia

Subdural space: between dura mater & arachnoid mater

Spinal Dura Mater

Extends from the margin of the foramen magnum to the S2 vertebra

Subarachnoidspace: bt arachnoid mater and spinal pia mater

Cerebral Cysterms:enlarged subarachnoid space at base of brain; contains CSF

Function: Protection ofcauda equinao

Spinal Cysterns:enlarged subarachnoid space w/ CSF from L1-S2 of spinal cord

Arachnoid Mater (avascular)

The pia mater ends at the dorsum of the coccyx

extensions from pia mater that att to inner surf of dura mater = anchorage

This ligament = partition bt dorsal & ventral roots (helps identification)

Selective Risotomy: cutting some of the rootlets in the sensory dorsal root

Ligamentum Denticulatum (21 pairs):o

Linea Splendence: Thickened part of the pia mater in the region of the anterior

median fissure (no clinical significance)

o

Thread-like extension of pia mater from tip of the conus medullaris

S2 --> pierces arachnoid & dura mater and attaches to dorsum of coccyx

Anchoring capacity to the spinal cord during extreme flexion

Filum terminale internum (Up to S2)

Filum terminale externum (after piercing the 2 meninges past the level of S2)

Filum Terminale (not very vascular)o

Modifications of the spinal pia mater

Tip of spinal cord has appearance of a horse tail since the spinal cord ends at L1/L2o

Lower 4 Lumbar nerves, Sacral, Coccgeal nerves and the filum terminale (non-

o

Cauda Equina

Spinal Pia Mater (Vascular layer)

Spinal Cord Cont'dMay-14-10

9:00 AM


4/63

nervous part of the cauda equina)

Performed at the level ofL3-L4 preferably (or between L2-L3)

Purpose:Spinal anesthesia, sampling of the CSF (microbiological, pathological analysis)

Position:Extreme flexion/Lateral decubitus (so that the spinal cord moves up)

Skino

Connective tissue (superficial/deep fascia)o

Supraspinous ligamento

Interspinous ligamento

Ligamentum flavumo

Dura Matero

Arachnoid matero

Layers pierced before reaching the subarachnoid space (from outside to inside):

When blood seen in needle = reached epidural space (due to venous plexus), go further in

Rate of collection of CSF:1 drop/min

Increased ICP (Normal ~ 0-20 mmHg in supine and -10mmHg in the vertical position)

= herniation of cerebellar tonsils and medulla (resp & CVS center) thru for magnum

o

Contraindications for LP

Normal CSF P: Supine = 80-100 mmH2O; Standing = 300-400 mmH2O in Spinal Cystern

If there is cont'd leakage of CSF which can't be replenished fast enough = brain -sensitive structures.

Dilation (widening) of the veins in the brain after procedure

Severe headache --> specific cause unknowno

Severe lower limb pain --> Damage to nerves (peripheral nerves) in the cauda equine

(lower lumbar, sacral, coccygeal), but they can regenerate bc peripheral nature

o

Complications after LP:

Lumbar Puncture (Spinal Tap)


5/63

2ND ORDER NEURONS CROSS TO OPPOSITE SIDE (CONTRALATERAL) SIDE OF BRAIN AT MIDLINE

OF MEDULLA = Internal Arcuate Fibers

From pons onward = "Medial Lemniscus Pathway"

2nd order neurons synapse at VENTRAL POSTEROLATERAL (VPL) NUCLEUS OF THALAMUS

THIRD ORDER

Project to postcentral gyrus via post limb of internal capsule --> SOMESTHETIC SENSORY

AREA (AREAS 3, 1, 2) in cortex

Thalamus

Discriminative touch, vibration, stereognosis, conscious proprioception

Input from: Paccinian & Meissner's corpuscles, joint receptors, muscle spindle & GTO

Anterior spinothalamic pathway --> light touch, pressure, tickle, itch

Lateral spinothalamic pathway --> pain, temperature

Anterior --> have crossed & uncrossed fibers

Posterior --> uncrossed fibers only

Spinocerebellar pathway -->proprioceptors to cerebellum

Cuneocerebellar pathway --> unconscious proprioception

Every sensation has to reach the thalamus before reaching the higher center (exceptOlfactory)

Discriminative General Senses --> carried by dorsal column

FIRST ORDER

Fasciculus gracilis (medial) carries

sensory from LOWER LIMB

Fasciculus cuneatus (lateral) carries

sensory from UPPER LIMB & THORAX

Dorsal Root Ganglion (DRG) --> SPINAL CORD

SECOND ORDERF gracilis synapses at GRACILE NUCLEUS

F cuneatus synapses at CUNEATE

NUCLEUS

Medulla Oblongata

TOUCH ON LEFT SIDE GOES TO RIGHT SIDE OF BRAIN

Tumor at C5 --> affects dorsal column tract = loss of discriminative general senses at &

below C5 on IPSILATERAL side

Lesion at Fasciculus Gracilis --> flaccid paralysis in lower trunk & lower limb

Lesion at Fasciculus Cuneatus --> spastic paralysis (weakness in muscle tone) In upper

IfRIGHT MEDIAL LEMNISCUS is damaged = loss of discriminative sensation on LEFT side

If damage on RIGHT SIDE OF T11 = lose sensation on SAME side below T11

Damaged sensory nerve pathways (posterior funiculus)

Lesions in parietal lobe = astereogenesis on CONTRALATERAL side

DDx: ask patient to close their eyes and identify a familiar object in their hand

Astereogenesis: inabili ty to discriminate bt objects of different shapes, textures, weight &

size based on just touch

Clinical Scenarios

Dorsal Column - Medial Lemniscus PathwayMay-17-10

9:00 AM


6/63

Loss of balance when person is standing straight w/ feet together

Conditions affecting dorsal columns of spinal cord

Conditions affecting sensory nerves (CN VII)

+ve = sensory ataxia (ie: loss of proprioception)

Can't use test bc even when eyes are open, these patients can't stand straight

-ve = cerebellar ataxia (ie: localized cerebellar dysfunction); vestibular disorder

Romberg sign: neurological test used to assess dorsal columns of spinal cord - essential for

proprioception & vibration


7/63

Lateral Spinothalamic Tractlocated in lateral column carries PAIN & TEMPERATURE sensations

Caused by cell injury orpotentialcell injury (ie : increased prostaglandins)

Indicates if there is something wrong with specific organ (ie: internal injuries)

Pain:noxious stimuli or unpleasant sensation; protective mechanism

Pain receptors: free nerve endings -NEVER adapts

Thickly myel inated fibers

Sharp & pricking pain

Latency period is very short-->NOT blocked by morphine

Very well localized

Less emotional = pain is not inhibited

Neospinothalamic Tract

Fast Pain carried by Group III (A) fibers

Dull, burning sensation

Slow onset -->CAN be blocked by morphine be fore pain reaches maximum

Diffuse (poor localization)

Emotional, autonomic response = can inhibit pain

Paleospinothalamic Tract

Slow Paincarried by Group IV (C) fibers

We don't take pain k ille rs for small pains

Analgesic Systemw/in body to maintain pain

Rubbing painful area will give temporary relief of pain sensation

When emotions are running high, pain systems are inhibited

Pain is inhibited by the body

Spinothala

mic TractAudio recording started: 9:18 AM May-18-10

Anterior, Post & Lateral Horn cells

Each lamina corresp to cel ls

Lateral Spinothalamic Tract

= pain pathway

Divided into many 10 laminas

Gray Matter of the Spinal Cord

You have to stop the pain sensation be fore it reaches the cortex

"Gate" is located in the posterior horn cell of the SPINAL CORD

T cells releases SUBSTANCE P - allows pain sensation to ascend

If release of substance P is blocked = inhibition of pain system

SG cells inhibitT-cells --> can't release Substance P --> pain can't ascend

Rubbing painful area rel ieves pain bc the collaterals of the thickly-myelinated, touch fibers stimulate

SG cells & T cells

Thinly-myelinated fibers inhibit SG cells and stimulate the T-cells

Gate Control Theory of Pain Sensation (Melzak, 1965)

Transection of lateral spinothalamic tract = CONTRALATERAL loss of pain & temp below lesion (pain isn't

completely lost bcspinoreticular pathwayalso carries pain)

Lamina 2: Substantia Gelatinosa Rolando (SGR)

Spinothalamic TractMay-18-10

9:09 AM


8/63

Audio

RecordingAudio recording started: 9:11 AM May-19-10

Pain perceived in area #43

Very rich in SEROTONIN

Magnus Raphae Nucleus in pons

Substantia Gelatinosa Rolando in spinal cord

1970 - endogenous morphine-like substances found (ie: enkephalin & endorphins)

Collaterals given from pain system to periaqueductal grey matter as system ascends which is connectedto Magnus Raphae Nucleus--> SGR --> release Serotonin (Descending Pain Inhibiting System)

Magnus Raphae Tractbt MRN & SGR = release of Serotonin from MRT & release ofENKEPHALIN from

SG cells = inhibits release of P-substance from Tcells

Opiate-binding receptor substances found in Periaqueductal Grey Matterin MIDBRAIN

When emotions are very high, stimulates Periaqueductal Grey Matter--> stimulates MRN --> releases

Serotonin --> SGR --> release Enkephalin - -> block P-substance

Insufficient blockage of P substance in normal conditions, but when emotions are very very high, the

whole pain system is blocked

Analgesics stimulate the Periaqueductal Grey Matter

Enkephalins INHIBIT P-substance

If pain system doesn't reach the cortex --> don't feel pain at all

Taking pain killers all the time decreases the sensitivity of the nuclei

Pain kil lers not needed for every little thing bc body will take care of itself

Somatic Pain felt in affected organ

Visceral Pain felt in superficial somatic structure (referred pain)

Diaphragm pain is felt in neck region (Dermatome C3, C4)

Gall Bladder pain is felt in back

Heart pain felt in shoulder region

Deeper diseased viscera & superficial somatic structure are derived f rom same dermatome

Every organ does NOT present referred pain (this theory doesn't completely explain)

Dermatomal Rule: during devl't, the deeper diseased viscera (ie: septum transversum) has carried

its inhibition f rom the higher region (ie: septum transversum descends from neck region)

1.

Higher brain center perceives pain in superficial somatic structure instead of viscera (is not

explained completely either)

Convergence: pain from superficial somatic structure & deeper diseased viscera synapse in spinal

cord next to each other (synapses converge in same segment) then ascend via pain system

2.

Facilitation:pain from superficial somatic structure gives off a collateral in spinal cord which

facilitates stimulation so that the higher brain perceives pain from superficial (but still doesn't

explain why brain doesn't perceive visceral pain)

3.

3 Theories: A combination of these theories explain Referred Pain

Referred Pain: Pain in deeper diseased viscera is felt in the superficial somaticstructure

Damage to area #43 doesn't affect sensation because there is BILATERAL INPUT

If you damage Area #43 on one side, you DO NOT lose pain & temperature sensation!

Pain comes from amputated limbs

Performed if pain ki llers aren't helping

If this sti ll presents in pain, must amputate limb (ie: in diabetic patients)

Selective Risotomy: take out few fibers of dorsal nerve root --> pain doesn't reach spinal cord

Each part of the body is received by its specific segment in Area 43 of cortex

That part of the cortex has learned where it i s receiving pain sensation from

Compression of neuromasses leads to stimulation in cortex = perceives pain in that region

If limb has been amputated, the cut ends of the nerves get entangled = Neuromass

Sensory Projection Law

Phantom Limb Pain

Descending Pain Inhibiting SystemMay-19-10

9:09 AM


9/63

Audio recording started: 9:21 AM May-20-10 Audio

Recording

Carry unconscious proprioception for Lower Limb & Lower part of the TrunkAscend to Cerebellum

Has to be faster so that body can prepare for mov't

These tracts conduct impulses at a faster rate than any other tract in the body (125 m/s)

Receptors are proprioceptors/stretch receptors in muscle fibers (ie: Golgi Tendon)

First order neurons in DRG

Clark's Column of Cells only present from T1-L2

Also receives fibers fromGroup Ia & II from muscle spindle

First order touch fibers give off collaterals to Lamina 7in Clark's Column of Cells (Nucleus Dorsalis)

Fibers cross on the same side of the spinal cord & ascend up through length of spinal cord

2nd order fibers collaterals of touch pthwy from Nucleus Dorsalis become Spinocerebellar Tract

Dorsocerebellar (DSCT):unconscious proprioception from spinldles via Group Ia & II

Ventrocerebellar

Spinocerebellar TractMay-20-10

9:14 AM


10/63

Audio recording started: 11:15 AM May-25-10Audio recording started: 11:22 AM May-25-10

Audio

Recording

Anterior --> carries efferent copy

T1-L2 go to Clark's column of cells (Nucleus Dorsalis)

Spinocerebellar Tractcarries unconscious proprioception from lower limb

From upper l imb fasciculus cuneatus ascends up to medullaoblongata and

give collaterals to accessory cuneate nucleus (behaves like Clark's column)

Follow ICP to cerebellum

Cuneocerebellar Pathway(homologous to spinocerebellar pthwy)

Above C8there is NO Clarke's column of cells

1st ORDER: free nerve endings (Merkel's disk); in DRG --> Tcells

2nd ORDER: dorsal horn in Lamina 4-6, cross via Ant grey commissure &

travel up as Ant STT

3rd ORDER: from thalamus to Areas 3, 1, 2 in cortex

This pthwy allows for maintainance of light touch & pressure sensation

Ventral Spinothalamic Tract (light touch, pressure)

OTHER ASCENDING TRACTS

Audio

recording .. .

Fibers from visual pthwy reach Superior Colliculus of tectum of midbrain

Fibers from sound pthwy & cutaneous sensations also carried via this pthwy

When you pinch the skin on the neck (or squeeze trapezius) = slight dilation of

ipsilateral pupil

Spinotectal: visual reflexes

Cell bodies located in DRG & ascend in brain stem --> go IPSI or CONTRA and then

ascend to thalamus & hypothalamus then diffuses

If lateral spinothalamic pthwy is damaged; this pthwy still maintains pain sensation

Spinoreticular:diffused pthwy, carries PAIN =emotional response

Spinoolivary

Upper motor neurons: from cortex or brainstem to spinal cord

Once a reflex gets conditioned (ie: withdrawal reflex), depending on how strong the stimuli is

If someone gets any noxious stimuli =WITHDRAWAL & COUNTEREXTENSION REFLEXES

Reflexes are due to plasticity of nerve fibers (we have learned and kept the reflex)

Each measures about 25 m, thickly myelinated fibers

Conduct impulses at rate of115-120 m/s

Motor unit: single alpha-motor neuron divides to supply many

Supply striated muscle f ibers at motor end plate

Alpha-motor neurons = Final Common Pathway of Sherrington

Lower motor neurons

Anterior Column/Grey Matter/Horn cells: contains LOWER MOTOR NEURONS

Reflexes

Cuneocerebellar PathwayMay-25-10

11:08 AM


11/63

Larger motor unit: supplies 100s

Smaller motor unit: supplies ~5 muscle f ibers

striated muscle f ibers (ie: a single alpha-motor neuron can supply

100s of extrafusal muscle f ibers) = mass contraction or skil led activity

supplies many muscle fibers

Sometimes becomes purposeless because don't contract to

prerequisite length; contraction depends onmuscle spindles

Phasic alpha-motor neurons: heavy li fting (mass contraction)

only supplies few muscle fibers

Contract to prerequisite length of muscle contraction

Tonic alpha-motor neurons: skilled activity

Monosynaptic reflex loop from Group Ia fibers from muscle spindle andinfluence from higher center (suppression or inhibition)

Gamma-motor neurons

Beta-motor neurons

Brown-Sequerd Syndrome:hemisection of spinal cord

Bilateral loss of pain sensation

Ipsilateral loss ofdiscriminative general senses (DGS)

alpha motor neuron damage = flaccid paralysis

Gamma motor neuron damage = atrophy

Lower motor neuron paralysis

Ipsilateral loss ofunconsciousproprioception (DSCT)

At level of Lesion (T7)

Contralateral loss of pain sensation

Ipsilateral loss of DGS

Ipsilateral loss ofunconsciousproprioception (DSCT)

Below lesion

Normal pain sensation

Normal DGS

Above lesion

Ex: 32 yo male stabbed in the back at T7; no 2-point discrimination & no pain in right lower limb.

Which pathway was damaged? PAIN


12/63


Recording

Monosynapticreflex loop from Group Ia fibers of muscle spindle

When you are flexing, you need to have inhibition of the extensors

Prevents excessive alpha-firing & may be antagonists

Strichnine (plant poison) inhibits these interneurons (Renshaw cells) = personwill die of convulsions

Renshaw cells --> INHIBIT adj alpha-motor neurons = inhibit the antagonistic muscles

As they supply striated muscle fibers, give collaterals to interneurons (many in grey matter)

Final common Sherrington Pathway

Alpha-motor neurons

supply intrafusal fibers (Nuclear bag & chain fibers) of muscle spindle (2-5 mm bundles) =

stretch receptors --> maintain muscle tone

Gama-motor neurons: less thickly-myelinated (10-25m) fibers; conduction = 10-45 m/s

Nuclear Bag Fibers

Nuclear Chain Fibers

Muscle spindles = 2-5mm inside muscle fibers = stretch receptors

Determined by muscle spindleMuscle tone: sustained muscle contraction (partial state of a muscle contraction)

Thinly - myelinated

Detect motion of muscle

Stimulation of1 = stimulate polar regions of nuclear bag fibers = stretch

Annulospiral nerve endings are non-contactile; when bag stretches, nerve

endings stimulated and info sent via Group Ia fibers to alpha-motor

neurons --> skeletal muscle fibers

Nuclear bag surr byAnnulo-spiral nerve endings = Group Ia fibers where it ends

Determines rate of change of contraction of muscle fibers

1 damage = lead-pipe rigidity

Parkinson's: 2 hyperactivity = cog-wheel rigidity

Dynamic (1):supply polarregion ofnuclear bag fibers --> Trail Endings

Static (2):supply polar region ofnuclear chain fibers --> non-contractile

Gamma motor neurons

Anterior

Horn Cells

5-10 mins of recording is missingAudio recording started: 11:46 AM May-26-10

Anterior Horn CellsMay-26-10

11:10 AM


13/63

Adaptation of change after contraction has happened

Group II fibers --> monosynaptic reflex loop to alpha fibers (extrafusal)

Gamma Reflex Loop

Constantly influenced by upper motor neurons

hyperactivity --> Clasp-knife rigidity = initial resistance followed by sudden

release

Lower motor neuron paralysis = ATROPHY bc intrafusal spindle becomes flaccid

Upper motor neuron paralysis = no atrophy


14/63


Recording - 2

Areflexia: paralysis caused by damage to lower motor neurons

Supplementary motor cortex (area 4 & 6)

Area 3,1,2 contributes

Fibers descend thrucorona radiata

Pyramidal system: originate from giant pyramidal cells in 3rd layer of cortex

Extra-pyramidal system

Motor system

Lateral corticospinal Tract

Anterior corticospinal Tract

Giant cells of Bertz: found in precentral gyrus and in anterior paracentral lobule

Bell's Palsy:paralysis of contralateral lower side of face (along lip)

Ask patient to close eyes & resist while you try to open it --> i f patient can't resist

= paralysis of obicularis oculi (CN III)

If patient can wrinkle forehead =CN VII damage

Test for CNVII damage: ask patient to smile & check if l ips are aligned

Damage to area above brain stem --> Upper motor neuron damage

Damage in brain stem --> Upper & Lower motor neuron damage

Damage below brain stem --> lower motor neuron damage

Transection = spastic hemiparesis w/ Babinski sign

Corticospinal

Corticonuclear fibers pass thru genu of internal capsule after corona radiata

Some fibers synapse in cranial nerve nuclei (lower motor neurons) of brain stem &

descend downward

Most fibers synapse on contralateral cranial nerve nuclei of brain stem

Corticobulbar

Pyramidal System

Not from cortex, other parts of the brain instead

Standing erect ctrld by this system

Vestibulospinal Tract--> extensor tone

Olivospinal--> compares skilled activity

Responsible for cutaneous stimulation

Tectospinal Tract--> vision

Reticulospinal--> activity

Rubrospinal--> flexor tone

Extra-pyramidal System

Descending TractsMay-27-10

11:04 AM


15/63

Houses cranionuclei, EXCEPTOlfactory & Optic N

Cardiovascular & Respiratory Centers in LOWER MEDULLA OBLONGATA Reticular System

Constantly charging NTs to be awake

Sometimes you are so tired and unaware of surroundings bc less active

Lesions always lead to crossed systems (ie: loss of pain & temperature on RIGHT

side of face, but LEFT side of body)

If there is a lower motor neuron paralysis on left side of tongue and upper motor

neuron paralysis on right side of body

Vertigo:nausea & dizziness

Stroke: ischemia in brain (different classifications); neurological symptoms last

greater than 24 hours

Transient Ischemic Attack (TIA): symptoms last connected to cerebellum

Brain Stem


16/63

Audio recording started: 11:25 AM May-28-10

Medulla

Oblongata

Capital punishment -->when you break the atlantoaxial joint = crushes odontoid process of axis &

cardiovascular centers in medulla obl

Motor derived from basal lamina

Sensory derived from alar lamina

Contains cranial nerve nuclei

Piriform-shaped structure; length ~3cm & max transverse diam in cranial part ~2cmUpward continuation of spinal cord at

Horizontal line just above att of 1st pair of cervical nerves; approximately crosses

middle of odontoid process of axis (C2)

Spinomedullary junction: Junction bt medulla & spinal cord

Cranial nerves that emerge from horizontal line (medial to lateral): CN VI, VII, VIII

Medulla Oblongata

Abducens (VI) bt medial part of sulcus &

pons

motor part of Facial is more medial

than sensory (Nervous intermedius)

Facial (VII), & Vestibulocochlear (VIII) bt

olive & lower part of pons

Nerves emerge out from medial to lateral from

horizontal sulcus:

Ponto-medullary junction: horizontal sulcus bt

medulla & pons

Striae Medullare: separates pons from medulla

oblongata on posterior side

Pons

Internal Structure of Medulla Oblongata

Medulla OblongataMay-28-10

11:21 AM


17/63

Inferior

Superior

Crossed motor paralysis:

Affects majority of limb & trunk muscles on contra side due to UMN decussation

Cause ipsilat paralysis of cranial nerve due to lack of decussation (ie: 3, 6, 12 --> facial muscles

on ipsi side)

Unilateral lesion in brainstem affecting UMN & LMN

Infarction of medial part of medulla

Ipsilateral = hypoglossal nerve damage = deviation of tongue on same side

Loss of discrete touch, conscious proprioception, vibration (damage to medial

lemniscus)

Contralateral = limb weakness (corticospinal tract damage)

Inferior: Medial Medullary Syndrome (Dejeune syndrome)

Manifestation of decompression syndrome

Dmg to paramedian branches of post cerebral art or perforating arteries

Ipsilateral: occulomotor nerve palsy w/ drooping eyelidContralateral: corticospinal & corticobulbar tracts damage (UMN dmg & lower facial muscles

& tongue

Substantia nigra: contralateral parkinsonism

Superior:Weber's syndrome= occulomotor nerve palsy

Alternating Hemiplasia: ipsil ateral /contralat presentation in diff parts of the body

Internal Structure of Medulla Oblongata


18/63

Audio recording started: 11:15 AM May-31-10 Brain Stem

Cont'd

Supraspinal Nucleus: part of central grey matter that is detached; descends down to C5

Lamina 2 of post grey column of spinal cord corresp to Substantia Gelatinoso Rolando (SGR)

Extended across entire length of medulla oblongata

Separatedfrom surface of medulla obl by Spinal Tract of Trigeminal Nerve

Spinal Nucleus of Trigeminal Nerve: in continuation with SGR; ends atPonto-medullary Junc'n

then continues with principle sensory nucleus of Pons

Pyramidal Decussation

Pyramids in ventral part --> corticospinal fibers (few corticobulbar)White matter --> ascending & descending tracts

Fibers from both cross = Internal Arcuate Fibers and then ascend as Medial Lemniscus

Grey matter -->Gracile Nucleus & Cuneate Nucleus

Sensory fibers are decussating

Fibers to all muscles of tongue except Palatoglossus & Styloglossus

Paralysis of genioglossus = tongue falls back --> closes oropharynx = death by

suffocation

Main bulk of tongue ctrld by Genioglossus ("li fe-saving" muscle bc protrudes

tongue to open airway)

Hypoglossal Nucleus: belongs to general somatic efferent (GSE) column

Cranial Nerve Nuclei appears here

Sensory Decussation

Ifspinal nucleus of damaged = loss of pain & temp from IPSILATERAL side

Iftrigeminal lemniscus damaged = loss of pain & temp from CONTRALATERAL

Alternating hemianesthesia --> loss of pain & temp ipsilaterally from

head/neck & contralaterally from body

Ifspinal lemniscus & trigeminal lemniscusdamaged in medulla

Clinical Scenarios

Pyramidal (Motor) Decussation of MedullaMay-31-10

11:12 AM


19/63

To test, ask patient to protrude tongue --> deviates to affected side

Injury to hypoglossal nerve =Lower motor neuron paralysis

Upper motor neuron lesions --> contralateral


20/63

Audio recording started: 11:21 AM June-01-10

Sensory

Decussat...

Medial Zone suppliedby AnteriorSpinalA. -->4thpart of Vertebral A

Strokesin vicinity of Brainstem = devastatingeffects

Medialzone of medulla damaged= INFERIORCROSSEDMOTOR PARALYSIS (aka: InferiorAlternating Hemiplasia)

No atrophy

Hyperreflexia

Rigidity

Positive Babinsky Sign

Damage to corticospinal fibers from pyramid = UPPER MOTOR NEURON PARALYSIS, contralateral

If right side of pyramid damaged --> entire LEFT side of body paralyzed

Hypoglossal Palsy: fasciculus, atrophy, flaccid paralysis

Damage to Hypoglossal Nucleus = damage to IPSILATERAL tongue muscles

If you see tongue muscle involvement + effects on contralateral side of body = MEDIAL MEDULLARY SYNDROME

Damage of Medial Lemniscus --> lose CONTRALATERAL touch, vibration, pressure, stereognosis

Medial Medullarysyndrome= blockage of Ant spinal A

Clinical Scenarios

Sensory Decussation of MedullaJune-01-10

11:21 AM


21/63

3 zones --> Medial, Lateral, Intermediate

Efferents --> cerebellum = climbing fibers --> synapse w/ purkinje cells

Stereotypic skilled activity

Olive produced by Inferior Olivary Nuclear Complex--> corticoolivary & spinoolivary fibers

Medial lemniscus

Tectospinal tract

Medial Longitudinal Fasciculus (MLF): lesion can cause nystagmusCN XII nuclei (efferent column in Hypoglossal column) --> anterior-lateral sulcus

Medial Zone

Afferents: sensory motor cortex (corticool ivary fibers), red nucleus (rubroolivary fibers), spinal cord from

anterior & lateral column (Spinoolivary fibers)

Efferents: Inferior cerebellar peduncle --> cerebellum --> climbing fibers (on purkinje cells)

Supplies soft palate, vocal cords

Nucleus Ambigus: gives bronchomotor fibers to cranial parts of CN IX, X, XI --> efferent column

Dorsal Nucleus of Vagus: gives preganglionic PS fibers to heart, sm muscles of resp & alimentary canal &

glandular epith; located lateral to hypoglossal nucleus

Receives taste sensation from VII, IX, X (sensory nerves of tongue)

Nucleus of Tractus Solitarus: belongs to visceral afferent column (SVA)

Preganglionic PS fibers to parotid gland via CN IX

Inferior Salivatory Nucleus: belongs to visceral efferent column

Intermediate Zone

Lateral Zone -->Anything that lies beneath ICP

Section of Medulla at Level of Olive

Medulla

Oblongat...Audio recording started: 11:28 AM June-02-10

Ventral & Dorsal Spinocerebellar Tracts

Lateral Spino-thalamic Tract (Spinal Lemniscus begins at Pont-medul lary junc'n)

Damage to LEFT Spinal Nucleus of Trigeminal N --> loss of pain & temp from

LEFT side of face & RIGHT side of body

Damage to Spinal Lemniscus

Alternating Hemianesthesia: ipsilateral loss of pain & temp from face &

contralateral loss of pain & temp from rest of body

Ipsilateral Horner's Syndrome

Lateral Medullary Syndrome (Wallenberg's Syndrome): most common brain stem

syndromes;caused by hemorrhagic stroke, embolic stroke, tumors

Supplied by Posterior Inferior Cerebellar Artery (PICA)

Other Structures in Lateral Zone

Medulla Oblongata at Level of OliveJune-02-10

11:22 AM


22/63

Hypothalamus = head ganglion of autonomic sys

Lateral horn cell of spinal cord only from T1-L2 = preganglionic fibers of

sympathetic (White rami communicantes)

Partial ptosis: partial drooping of upper eye lid --> due to damage to

descending autonomic fibers

Myosis:constriction of pupil resulting from paralysis of dilator muscle of iris

Anhydrosis: no sweating from affected side (ipsilateral)

Enopthalmus: sunken eyeballs bc fat loculi in orbit are supplied by post-

ganglionic sympathetic fibers

Vasodilation= increased blood flow i n face & neck (flushing)

Dysphagia: diff iculty swall owing bc damage to Nucleus Ambigus --> all pharyngeal

muscles paralyzed

Hoarseness of voice: paralysis ofRecurrent Laryngeal (Vagus) --> Nucleus Ambigus

Ipsilateral Ataxiabecause of damage to inferior cerebellar peduncle

Decreased sensitivity to li ght touch due to damage to spinal nucleus of trigeminal


23/63

Audio recording started: 11:20 AM June-03-10 Audio Rec...

Pons: bridge bt midbrain, medulla & cerebellum

External Features (Ventral)

PonsJune-03-10

11:17 AM


24/63

Audio recording started: 11:14 AM June-07-10 Pons Cont'd

Basilar Part of the PonsJune-07-10

11:11 AM


25/63

Audio recording started: 11:16 AM June-08-10 Pons Cont'd

Verticle fibers

Horizontal fibers

Ponti nuclei

Neurobiotaxis phenomenon --> Facial N loops around abducens nucleus

Dorsal to trapezoid body in tegmentum= chain of lemniscus system

Basilar Part of Pons at level of Facial Colliculus

Pons at level of Facial ColliculusJune-08-10

11:14 AM


26/63

Audio recording started: 11:10 AM June-10-10 Pons at

level of Tri ...

Just above the facial colliculus

Medial lemniscus (cell bodies in medulla)

Spinal lemniscus (cell bodies in dorsal horn of spinal cord --> Laminas 4-6

Trigeminal lemniscus

Lateral lemniscus (cell bodies in superior olivary nuclear complex (2o) & cochlear nuclei (3o))

Muscles of mastication; Masseter, temporalis, med & lat pterygoids, tensor tympani,

tensor veli palati, anterior belly of digastric

Bronchomotor fibers: from motor nucleus of trigeminal N --> joins the lateral thicker sensorypart of nerve --> trigeminal ganglion; supplies muscles derived from 1st pharyngeal arch

Pons at the Level of Trigeminal Nuclei

TEST 1 ON MONDAY JUNE 14

If Trigeminal N is intact, but can't feeltouch sensation during corneal reflex =

lesion in principal nucleus of pons in

brainstem

Pons at level of Trigeminal NucleiJune-10-10

11:09 AM


27/63

Usually unilateral damage

Hyporeflexia (NO ATROPHY)

Rigidity

Spasticity

Damage to corticospinal tract = contralateral hemiparesis of body (UPPER MOTOR

NEURON TYPE OF PARALYSIS)

Symptoms

Lower motor neuron type of Lateral Rectus paralysis --> medial strabismus (eye

will move to medial side)

Upper motor neuron type of paralysis on contralateral side of body --> loss of

proprioception & tactile pressure

Raymond's Syndrome (aka Alternating Abducens Hemiplasia): damage to Abducens

nucleus

ipsilateral LOWER MOTOR NEURON PARALYSIS of facial musculature

Contralateral UPPER MOTOR NEURON PARALYSIS of body

Miller-Gubler Syndrome (aka Alternating Facial Hemiplasia):

Medial Pontine Syndrome: results when shortcircumferential branches of Basilar A in pons are

damaged

Ipsilateral limb ataxia (due to damage to ICP)

Partial Ptosis

Myosis

Anhydrosis

Enopthalmus

Ipsilateral Horner's syndrome (due to damage ofdescending autonomic fibers)

Contralateral loss of pain & temp from body (damage to spinal lemniscus)

Ipsilateral loss of pain & temp from face (damage to spinal nucleus of trigeminal)

Lateral Pontine Syndrome:damage to long circumferential branches of Basilar A

Alternating Trigeminal Hemiplasia: paralysis of muscles of mastication

Hearing loss due to involvement of cochlear component of vestibulocochlear N

Ipsilateral Facial paralysis due to involvement of Facial Nerve (not nucleus)

Lateral Pontine Syndrome

Lateral Medullary Syndrome: Dysphagia, hoarseness of voice

How to differentiate bt Lat Medullary & Pontine Syndromes

Pontine Syndromes


28/63

Audio recording started: 11:23 AM June-15-10 Midbrain

Shortest segment of the brainstem

Cerebral aqueduct of Sylvius: in center of midbrain, communicates the 3rd

ventricle to 4th ventricle; CSF flows through

Mamillary bodies w/in fossa

Interpeduncular fossa:between 2 peduncles

Quadrigeminal bodies ( Corpura quadrigemina)

2 pairs of colliculi (Inferior & Superior)

inferior brachium connects inferior colligate to MGB

Tectum (dorsal) = 4 elevations

Tegmentum

Occulomotor N (CN III) emerges from medial side

Trochlear N (CN IV) emerges from lateral surface of crus cerebri

Crus cerebri (ventral): crossed from above, downwards byoptic tract

Cerebral peduncles (2)diverge

Midbrain

Section of Midbrain at level of Inferior Colliculus

MidbrainJune-15-10

11:07 AM


29/63


Midbrain

Cont'd

Section at Level of Inferior Colliculus

Midbrain Cont'dJune-16-10

11:10 AM


30/63

Audio recording started: 11:11 AM June-17-10 Midbrain ...

Pair of Inferior & Superior Colliculi

Tectum of Midbrain

Afferentsfrom Lateral Lemniscus and from the opposite side of i nferior colliculus,MGB

via Inferior Brachium

Inferior Colliculi: responsible for auditory reflexes

Quadrigeminal bodies

Paramedian perforators of terminal Basilar APeduncular perforating branches of posterior cerebral A

CONTRALATERAL HEMIPARESIS OF BODY (UMN paralysis of corticospinal)

CONTRALATERAL HEMIPARESIS OF FACE (UMN paralysis of corticobulbar)

Damage of crus cerebri --> corticospinal & corticobulbar fibers

Lesion of crus cerebri of midbrain & Occulomotor Nucle ar Complex

Weber' s Syndrome (Ventromedial Superior Midbrain Syndrome)

Syndromes of the Midbrain

Signs of le sion: fi xed dilated pupil doesn't accommodate, ptosis devl'ps followed by a complete inte rnal ophthalmoplegia

(masked ptosis); unopposed lateral rectus = outward deviation of the e ye

Occulomotor Nerve (III) Nucleus: indirectl y innervated by corticobulbar tract

Signs of lesi on: diplopia due to weakness of downward & inward mov't, vertical diplopia

Trochlear Nerve (IV) Nucleus: indirectl y innervated by corticobulbar tract

Edinger-Wespal Nucleus

Midbrain

Signs of lesi on: weakness of jaw clenching & side to side mov't

LMN--> j aw deviates to weak side when mouth opened; fasciculation of temporalis & masseter

Mesencephalic

Trigeminal (V) Nucleus:directly innervated by corticobulbar tract

Pons

Cranial Nerve Nuclei in Brainstem

Midbrain @ Superior ColliculusJune-17-10

11:09 AM


31/63

Principal

Spinal

Can't look laterally; eye i s deviated medially bc unopposed action of medial rectus

Abducens (VI) Nucleus: indirectly innervated by corticobulbar tract

Signs of lesion: facial weakness

LMN--> f orehead paralyzed; due to Bell's palsy, oti tis media, skull fracture, cerebello-pontine angle tumors, parotid tumors,

Herpes Zoster (Ramsay-Hunt syndrome), Lyme dise ase

UMN --> spares the forehead, stroke, tumor

Facial (VII) Nucleus:directly innervated by corticobulbar tract

Cochlear Nucleus

Vestibular Nucleus

Signs: palatal weakne ss, nasal regurgitation, palate moves asymmetrically when patient says 'ah'; recurrent nerve pals y =

hoarsness, loss of vol ume (bovine cough)

Nucleus of Vagus (X)

LMN--> wasting ofipsilateral side of tongue, with f asciculation; on protrusion, deviates to affected s ide (but away from the

side of a centrallesion)`

Hypoglossal (XII) Nucleus: directly innervated by corticobulbar tract

Spinal nucleus of Trigeminal (V)

Nucleus Ambigus

Solitary Nucleus

Medulla


32/63

Audio recording started: 11:09 AM June-18-10 Midbrain S.. .

"corticonuclear" fibers (f rom cortex to cranial nerve nuclei )

UMN --

LMN --> begins in neural axis ( ie: brain stem, spinal cord) and supplies target cells

Not all of the cranial nerves have LMNs

Olfactory, Optic, Ve stibulocochlear are purely sensory nerves (no motor component)

Motor nucleus of facial nerve supplie s face; lower part of nucleus suppl ies lower part

of the face, upper supplies upper part of face

Contralateralf acial palsy

Recall: Weber's Syndrome

Corticobulbar Fibers

Involvement of CN III

Hemichorea due to involvement of red nucleus &subthalamic nucleus

Ataxia & tremor due to involvement ofred nucleus

Ipsilateral CN III fascicular palsy

Paramedian perforators of terminal Basilar A, Interpeduncular branches of Posterior

cerebral A

Paineras syndrome?

Benedict's Syndrome (Paracentral Tegmental Superior Midbrain Syndrome)

Midbrain SyndromesJune-18-10

11:09 AM


33/63


External F.. .

Part of hindbrain; situated in the posterior cranial fossa w/ pons & medulla oblongata

4th ventricle cavity bt pons & cerebell um

"silent" area of the brain bc upon electrical stimulation, no conscious response

Ex: flex ion has to be stopped before extension can start

Timing of an action; if timing is off (i e: dysmetria) will overshoot or fall short when reaching

Smooth progression bt mov'ts - -> Compares actual mov't & intended mov't

Intensity/velocity of muscle contraction

Learns from mistakes (ie: playing a piano)

Responsible for

Plasticity of neuronal pools: ability to learn skil ls (ie: swimming, riding bike)

Motor cortex = planof action to cerebellum

Receives sensory info from periphery (ie: vi a spinocerebellar pthwy) andfrom motor cortex

Dysdidakhokinesia (Adidakhokinesia): absence of 2 alternating mov'ts

"organ of balance"

ICP (Restiform body) --> Medulla

MCP (Brachium pontis) --> Pons

SCP (Brachium conjunctiva) --> midbrain

Cerebellum connected to 3 parts of brain stem vi a cerebellar peduncle

Vermis: anatomical midline worm-like structure

Hemisphere: extend from vermis

Cerebellum

Divisions of Vermis

Lingula

Central Lobule

Culmen

Declive

Folium

Tuber

Pyramid

Uvula

Nodule

External FeaturesJune-21-10

11:13 AM


34/63


Cerebellum

Cont'd

Mossy fibers -->all other afferents

Climbing fibers --> All of the afferents from Inferior Olivary Nuclear Complex

All inputs i nto cerebellum can be classified into 2 types = excitation of cerebellum

Festigial Nucleusderives fibers from Vermis

Globus

Emboliformis

Nucleus Interpositus

Dentate Nucleus

Deep Cerebellar Nuclei

Outer = Molecular layer

Middle = Purkinje cell layer

Deep = Granular cell layer

Cerebellar Cortex = 3 layers

Internal Features of the Cerebel lum

Afferent fibers except inferior olivary input

2/3 of medullary center

Mossy fiber Rosette

Granular Cell Dendrite--> main afferent input

Synapse on granule cell dendrite; (GABA --> inhibitory)

Surrounded by astrocyte foot process

Golgi cell Axon

Afferent terminals on G RANULAR LAYER

Synaptic Glomerulus

Internal FeaturesJune-22-10

11:14 AM


35/63

Audio recording started: 11:15 AM June-23-10 Cerebellu...

Surrounded around 1 purkinje cell ; 30 million functional units

Purkinje fibers are the only output of cerebellar cortex

Functional Unit

Cerebellu...

Audio recording started: 11:21 AM June -23-10

Effect of Alcohol on Purkinje cells

Cerebellothalamic fibers from 3 deep nuclei to VPLo, VLc, CL

Cerebeloorubral fiber predominantly from Dentate nucleus & nucleus globusus

SCP

Fastigiovestibular fiber

ICP

Efferents of Cerebel lum (MAILY FROM SCP)

Cerebellum Cont'dJune-23-10

11:15 AM


36/63


Connection

s of the C...

Main Connections of the Vestibulocerebellum

Cerebellum & Automatic Motor Control

Functions of Cerebellum

Main connections of Paleocerebellum

Main connections of Neocerebellum

Pyramidal Tract & Associated Circuits

Connections of the CerebellumJune-24-10

11:15 AM


37/63

Maintenance of Equilibrium -- >balance, posture, eye mov't

Coordination of automatic mov't of walking & posture maintenance --> posture, gait

Motor learning = motor skil ls

Cognitive Function

Decomposition of mov't--> breaking down a smooth muscle act into a number of jerky

awkward component parts

Dysmetria(past-pointing): inabil ity to arrest muscular mov't at desired point

Dysdiadochokinesia (Adidydakokinesia):inability to perform rapid alternating mov'ts (rapid

supination & pronation of hands)

Normally, when flexors are working, we need to have a gradual release of extensors

If extensors stop immediately = jerky mov't

If flexors are not inhibited upon extension = rebound phenomenon

Rebound phenomenon of Holmes

Ataxia: incoordination of mov't; gait ataxia, truncal ataxia, titubation

Intention tremor: dysmetria that occurs during a voluntary action

Nystagmus:form of dystaxia consisting of to -and-fro eye mov'ts (ocular dysmetria)

Malignant; most common in vermis; originate from granular layer of cereb cortex

Obstruct passage of CSF = hydrocephalus

Archicerebellar lesion --> medulloblastoma

Paleocerebellar Lesion --> gait disturbance

Neocerebellar Lesion --> hypotonia, ataxia, tremor

Disorders

If there is a lesion in vermis = truncal ataxia

Paravertebral lesion = gait ataxia

Lateral zone lesion = incoordination = tremor

Arnold Chari Malformation: tonsils are el ongated & pushed down thru foramen

magnum --> blocks flow of CSF

Herniation of cerebellar tonsils --> chiari malformation

Action/intention tremor:dysmetria that occurs during a voluntary mov't

Caused by alcohol abuse = atrophy of rostral vermis

Gait, trunk, & leg dystaxia

Anterior vermis syndrome: leg region of anterior lobe

Result of brain tumors in children; caused by medulloblastomas or

ependymomas

Truncal dystaxia

Posterior vermis syndrome: flocculonodular lobe

Arm, leg, trunk & gait dystaxia

Cerebel lar signs are ipsilateral to lesion

Hemispheric syndrome:from brain tumor or abscess

Lesions of each division of cerebellum

Cerebellum

Intra-axial f ibers of Oculomotor nerve roots

Corticobulbar tracts --> contralat weakness of lower face (VII ), tongue (XII), palate (X)

Corticospinal tracts --> contralat hemiparesis of trunk & extremities

Weber's Syndrome:occlusion of posterior cerebellar A & aneurysm of circle of Will is

Complete ipsilateral oculomotor nerve paralysis

Eye abduction & depression bc unopposed action of LR (CN VI) & SO (CN IV)

Paralysis of le vator palpebrae =severe ptosis

Complete internal ophthalmoplegia = ipsilateral fixed & dilated pupil

Occulomotor nerve roots (intra-axial)

Contralateral cerebellar dystaxia w/ intention tremor

Red nucleus & dentatorubrothalamic tract

Contralateral loss of proprioception, discriminative tactile se nsation & vibration

sensation from trunk & extremities

Medial lemniscus

Benedikt Syndrome:occlusion or hemorrhage of paramedian midbrain br of post cerebral A

Complete Occulomotor palsy --> direct & indirect light reflex

Have to have alternating syndromes for it to be midbrain lesion

Midbrain

Results from lesions of MLF in dorsomedial pontine tegmentum; affect 1 or both MLFs

Sign of MS

Medial rectus palsy on attempted lateral gaze

monocular nystagmus in abducting eye w/ normal convergence

Lesions of CN VI = all MLF si gns & lateral rectus paralysis w/ internal strabismus

Internuclear opthalmoplegia (INO)aka MLF syndromePons

Dorsal Tract -->unconscious proprioception from lower extremitiesvia ICP

Ventral tract --> unconscious proprioception from lower extremitiesvia SCP

Spinocerebellar pathway

+ve --> sensory ataxia = loss of proprioception

-ve --> cerebellar ataxia = ve stibular disorder

Rhomberg's sign: loss of balance when subject stands w/ feet together & closes the eye s

MUST KNOW FOR TEST TOMORROW


38/63

Audio recording started: 11:14 AM June-29-10 Test 2

Purkinje cells are only output from cerebellar cortex (A)1.

Left lower lid drooping , left angle of mouth sagging & saliva dripping; patient can't close eyes &

difficulty exposing teeth on left side; lesion involves? Facial nerve; Lower motor neuron paralysis (B)

2.

Flocculus & nodules = balancea.

Cerebellum ctrls balance by controlling vestibular nucelib.

c.Juxtarestiform body is an important link in this pathwayd.

How cerebellum controls balance (which is NOT correct)3.

Spastic paralysis on left upper & lower limbs, loss of fine touch & proprio in upper & lower body on left,

flaccid paralysis of lateral rectus. Where is lesion? Right side of pons

4.

Tremor is involved with lateral zone not cerebellum

Lesion in flocculonodular lobe & festigial nucleus does NOT produce none of the above5.

Blurred visiona.

Hyperacusis (paralysis of stapedius - facial nerve)b.

Inabili ty to chew (muscles of mastication)c.

Inabili ty to feel face (trigeminal)d.

Inabili ty to shrug shoulder (spinal part of accessory)e.

Inabili ty to close right eye, weakness in right orbicularis oculi (facial nerve), other symptoms?6.

IIIa.

IVb.

Vc.

VId.

Sudden onset of headache at night, complete ptosis on left, eye l ies down and out with fixed di latedpupil; which cranial nerve involvement

7.

8.

Test 2June-29-10

11:14 AM


39/63


Basal

Ganglia

Subcortical masses of gray matter (inner core)

Lentiform nucleus = biconvex mass of gray matter in concavity of internalcapsule

Caudate Nucleus = C-shaped grey matter

Medially --> Caudate nucleus, Lentiform nucleus

Internal capsule divides corpus striatum into 2 components

Corpus Striatum: largest component of the basal nuclei

Clostrum

Subthalamic Nucleus

Amygdaloid complex

Stereotyped activity

Subcortical center for extra-pyramidal pathway

Reticulospinal

Tectospinal

Vestibulospinal

OlivospinalRubrospinal

Influences LMN of brainstem & spinal cord via

Pyramidal pathway (corticospinal, corticobulbar) --> skillful voluntary act ofdistal musculature of

distal part of limbs (ie: hands, feet)

Area #6 = cortical center for extra-pyramidal pathway; Supplementary Motor Area

Extra-pyramidal pathway are multineuronal & multisynaptic pathways -->proximal part of

limb --> responsible for initiating action (ie: when writing, your shoulder needs to move first)

Classified into 2 types: Hypokinetic, Hyperkinetic

Akinesia --> no mov'ts

Bradykinesia

Hypokinetic

Parkinson's disease: also falls in hypokinetic category (worse)

Choreas -->Huntington's, Syndenham's

Hemiballism

Athetosis

Hyperkinetic

Basalganglia disease --> lose initiation of skilled voluntary act of proximal distal musulature

Direct & Indirect Pathway of Basal Ganglia

Basal Nuclei

Basal GangliaJune-29-10

11:07 AM


40/63


41/63

Basal

Ganglia C...


Principal afferents from 3 sources

Corticostriate fibers from CORTEX

Thalamostriatal fibers from Venteroanterior, Venterolateral THALAMUS

Nigrostrial fibers from SUBSTANTIA NIGRA

Amygdalostrial fibers from AMYGDALOID

Connections to Striatum

Striopallidal fibers: Most of efferents go to Globus pallidus externum

Strionigral fibers: Some go back to Substantia Nigra

Connections FROM Striatum

Lesion in CORPUS STRIATUM (probably in Putamen)

Complication of Rheumatic fever; usually recovers spontaneously in 1-4 mo

Fine, disorganzined, random mov'ts of tongue, face & extremities

Accompanied by muscular hypotonia

Exaggeration of assoc mov'ts

Common in children

Syndenham's Chorea

Lesion in Corpus Striatum (esp CAUDATE NUCLEUS) & Cerebral Cortex

Autosomal dominant (chromo 4); fatal

Insidious onset: usually 30-50 yrs

Choreic mov'ts assoc w/ emotional disturbances

Grotesque gait & severe ..

Dementia only results if there is involvement w/ cerebral cortex

Huntington's Chorea

Lesion in SUBTHALAMIC NUCLEUS

Commonly as a result ofcerebrovascular accidents (ie: stroke)

Mov'ts are cont's & exhausting, but cease during sleep

Can be fatal due to exhaustion

Can be ctrld by phenothiazines & sterotaxic surgery

Hemiballism

Lesion in SUBSTANTIA NIGRA (pars compacta)

Difficult to stop mov'ts once activity initiated

Can't express feel ings in face (masked face)

Resting tremor

Cog-wheel rigidity

Parkinson's Disease (Paralysis Agitans)

Hyperkinetic Disorders

Basal Ganglia Cont'dJune-30-10

11:09 AM


42/63

Audio recording started: 11:21 AM July-05-10

CerebrumCerebrumJuly-05-10

11:21 AM


43/63


44/63

Audio recording started: 9:06 AM July-06-10 Lobes of

the Cereb...

Lesions of motor cortex = contralateral spasatic paralysis of the body

Afferents from Area 3,1,2 via commissural fibers (association fibers)

Efferents =corticospinal & corticobulbar fibers

Primary Motor Cortex (Area 4)

Premotor Cortex (Area 6)

Frontal Lobe

Lesion of prefrontal cortex = lose initiative, carelessness, euphoria, vulgarity

Mental illness treated w/ bi lateral prefrontal lacotomy (not as common today) = behavioral changes

Excessive blood flow to prefrontal cortex also produces same problems (unknown reason)

Frontal LobeJuly-06-10

9:05 AM


45/63


Parietal Lobe

Over 1/5 of total cortex

Primary somatosensory

Secondary somatosensory

Gustatory

Association

Features

Involves association areas of cerebral cortex

Association areas are responsible for info processing bt sensory input & motor output

Cognition: abili ty to pay attention to identify & plan meaningful responses to external stimuli or internal

motivations

If vigorously ask if the l imb is there, then they wi ll admit it

Frequent consequence of stroke on right side of brain = neglect everythi ng on left

NOT blindne ss --> Patients can recognize & name objects

Doctor wiggle s a finger --> patient sees the fi nger, but if the doctor doesn't move the finger,

patient is oblivious --> they don't pay attention to left side

If there is damage to left side, you wil l never have neglect to right side bc paying attention is

function of dominant hemisphere (right brain)

Parietal (Contralateral) neglect syndrome: if lesi on on right side, can't recognize anything on the left (ie:

neglect anything that is on the left of patient)

Parietal Association Cortex: paying attention to complex stimuli

Temporal Association Cortex: identification of stimuli

Frontal Association Cortex: planning responses

Inputs are different from the rest of cerebral cortex

does NOT receive direct inputs from sensory organs

Inputs refle ct highly processed sensory info from other areas of the cortex

Area 22: Sensory Speech Area (Wernicke's speech area): forms words & sentences,

Association Cortex

Parietal LobeJuly-07-10

11:15 AM


46/63

Abil ity to speak via fibers connected to Areas 44 & 45 --> Motor Spee ch Area (Broca's)

comprehension of spoken word

Area 41 & 42: hear the words and sends stimul i to Area 22


47/63

Audio recording started: 11:34 AM July-08-10 Cerebrum

Cont'd

Motor programs for speech production

Projects to motor cortex areas controlling vocal cords, tongue & lips

"nonfluent", "motor","Boca's"aphasia--> agrammatical,nonfluent speech.

Lesion causes expressive aphasia w/ poor articulation, short sentences, slow speech

Broca's area (44 & 45): motor speech center (located in inferior gyrus)

Hemisphere w/ language = dominant hemisphere (most commonly left hemisphere)

Language Areas of the Brain

Global Aphasia-->damage todominanthemisphere

If damagedominanthemisphere before6 years old= transferof language toNON-DOMINANT

Language AreasJuly-08-10

11:20 AM


48/63

Test 3 Key


Parkinson's disease1.

Cog-wheel rigidity2.

Lateral pontine doesn't include tongue paralysis3.

Efferent fibers from cerebellar to deep nuclei are axons from purkinje cells4.

Transverse section has E-W and red nucleus5.

Muscles of mastication are paralyzed (damage to motor nucleus of trigeminal) and can't feel

texture of food wi ll also have loss of tactile pressure on right face

6.

Proprioceptive info from lower body is NOT mainly carried by SCP (b)7.Parkinson's8.

Bradykinesia, rigidity, resting tremor (all of the above)9.

Substantia nigra10.

c11.

GABA everywhere except corticostriate (glutamate) D12.

Lentiform nucleus = putamen & globus pall idus13.

Left neglect = lesion in Parietal lobe14.

Left neglect = Right parietal cortex15.

c16.

Given17.

e18. All deficits are NOT contralateral to lesion (D)19.

Ventral spinocerebellar pthwy in SCP20.

Impaired comprehension & repetition = Wernicke's (B)21.

Normal fluency, comprehension, impaired repetition = conduction aphasia (D)22.

Impaired fluency, comprehension & repetition = global 23.

Impaired fluency, repetition, comprehension intact = broca's (A)24.

Chromosome 4 for Huntingtons25.

Answers

Test 3 Key


Test 3 KeyJuly-13-10

11:16 AM


49/63


Occipital

Lobe

Extended along calcaranean sulcus

Lunate sulcus posteriorly

Receives temporal half of same side of vision & nasal half of opposite side

Afferent from LGN

Lacks ability to analyze and discriminate

Anterior part --> Peripheral vision

Posterior part --> Macular vision

Occlusion of posterior cerebral artery

Macular vision spared due to presence of collateral blood supply from middle

cerebral A

Lesion =homonymous hemianopsia

Area 17: Primary Visual Cortex

Analyzes & discriminates new images vs past images

Area 18: Parastriate cortex

Area 19: Peristriate cortex

Occipital Eye Field

Superior longitudinal bundle between area

Area 18 & 19 connected toSuperior Colliculus for scanning mov'ts and protective measures

via Tectobulbar pathway

Corticotectal fibers from Area 18 & 19

Area 18 & 19 receives info from bilateral Area 17 (can analyze & discrimination)

Processing of color, mov't direction (scanning mov'ts), visual interpretation

Can't recognize a face you have already met

Vision is normal

Alzheimer's --> lose abili ty to recognize familiar faces (no facial recognition)

Lesion to Area 39 = visual agnosia (can't identify images that have been seen before)

Area 18 & 19 efferent to Area 39 (higher association visual cortex)

Association cortex: storage of past visual images

Visual Lobe

We always move body parts opposite to mov't of eyeball

Ex: flinching if something thrown towards you

Vestibuloccular Reflex

Occipital LobeJuly-13-10

11:46 AM


50/63

Audio recording started: 11:36 AM July-14-10 Cerebrum

Cont'd

Fibers are predominantly from pyramidal cells and stellate cells of cortex

Enables us to react to sensory input

Short association fibers (aka cortical U-shaped fibers) --> connect adjacent gyri

Superior longitudinal bundle: connects frontal eye fie ld (Area 8) to occipital eye fi eld (Area

18 & 19) w/in same hemisphere

Arcuate fasciculus: between Area 22 (Wernicke's) & Area 44, 45 (Broca's)

Cingulum: bundle which becomes most important part ofPapez Circuit(memories)

Long association fibers

Association fibers: comm w/ adjacent gyri (ie: bt Area 3,1,2 & Area 4)

Intermingle w/ commissural fibers (anterior commissure & corpus callosum)

Cont's w/ internal capsule, downwards

Corona radiata: project from vicinity of corpus striatum

Corticopetal fibers: fibers that go INTO cerebral cortex

Corticofugal fibers: fibers that go OUT of cerebral cortex

Continuous upwards with corona radiata

Continuous downwards with crus cerebri of midbrain

Anterior Limb

Genu

Posterior Limb

Sublentiform part & Retrolentiform part

Internal capsule: highway for afferents & effe rents of cerebral cortex

Neo-cortical: from neocortex

Fimbria derived from hippocampus

Allo-cortical: from old cortex

Projection fibers: project beyond the cerebrum (afferents & efferents)

Commissural fibers

White Matter

White MatterJuly-14-10

11:36 AM


51/63

Audio recording started: 11:11 AM July-15-10 Cortical

Connectio...

Corticospinal fibers (upper limb, trunk, lower limb)

Corticobulbar fibers

Lesion =contralateral hemiparesis of body

Anterior 2/3

If these f ibers are intact does NOT = complete paralysisCorticorubral fibers

From ventral anterior & midline nucleus of thalamus to Area 4 & 6

Superior thalamic radiation fibers

Corticostriate fibers

Fasciculus thalamicus

Posterior 1/3

Posterior Limb

Internal Capsule

Connect identical area of one hemi to the opposite hemi across midline (most are

homotopical, but few are heterotopical - go to diff areas)

5 sets of commissural fibers

Anterior Commissure

Posterior Commissure

Hippocampal CommissureHebelunar Commissure

Connects almost ALL the identical areas to opposite hemisphere EXCEPTprimary

somasthetic sensory area of hand (3,1,2) & primary visual area (Area 17)

Language, analytical, clinical thinking, intellectual ability, calculations

95% of population is left hemisphere dominant

Spatial arrangements, artistic skil ls, musical abilities, non-verbal abilities

Non-dominant hemisphere (right)

These areas are also in opposite hemisphere, so info is sent via corpus

callosum, but one side is stil l dominant

Language areas: Broca's (44, 45), Wernicke's (22), Area 29, 40

Learned expression --> left hand will know what right hand is doing

Writing = upper part of Area 6 (Supplementary Motor Area)

Cut corpus callosum to prevent series of traffic between hemispheres (ie: severe

epilepsy) -->split brain preparations

Corpus Callosum (~300 mill ion fibers)

Commissural Fibers

Cortical Connections Cont'dJuly-15-10

11:11 AM


52/63

Audio recording started: 11:18 AM July-16-10 Thalamus

Mass ofgray matter split in between 3rd ventricle

3rd ventricle: cavity in midline

extends from inter-ventricular foramen (of Monroe) to upper end ofcerebral

aqueduct

Divides i nto 2 parts:hypothalamus (below) & (epi)thalamus(above)

Hypothalamic sulcus: runs in middle of diencephalon

Sagittal section

Diencephalon

If thalamus doesn`t function a pin-prick sensation becomes a highly unbearable pain

sensation; music that you normally like becomes highly unbearable

All sensory modalities integrated in thalamus EXCEPTOlfaction

Thalamus

ThalamusJuly-16-10

11:16 AM


53/63


Diencephalo

n Cont'd

Thalamus

MGB --> auditory fibersLGB --> light

VA & VL --> motor function

VPL/VMP --> somatosensory (ie: VPL receives pain & temp)

SpecificRelayNuclei -->receive specificsensations

Pulvinar/Lateral Posterior Complex

Lateral Dorsal (LD)

Connected to pre-frontal cortex & amygdaloid complex

Dorsal medial (DM) --> emotions; depth of emotions/tone of feelings

Association Nuclei --> no specifi c projections, associated w/ emotions

Part of VA

Cenromedian nucleus

Reticular nucleus

Parafollicular nucleus

Intralaminar --> Important for ARA system

Non-specific--> no specific function, but is associated (ie: DM related to prefrontal cortex)

Diencephalon Cont'dJuly-20-10

11:14 AM


54/63

Ependymal-lined (columnar epith l ining) cavities where produc'n of CSF occurs

4th ventricle = cavity ofhindbrain

Posteriorly--> cerebellum

Ventrally--> upper part of medul la & pons

Diamond-shaped space

Superior angle -->comm w/ 3rd ventricle via cerebral aqueduct Inferior angle -->cont's w/ central canal

Foramen of Luschka --> CSF to pontine cistern

Run venteromedially --> cerebellar peduncle

2 lateral angles

4th Ventricle

Tent-shaped

Divides roof into upper & lower parts

Formed by converging fibers of SCP = superior medullary velumUpper part: nervous part

Ependyma

Tela-choroidae of 4th ventricle: double-layer of the pia mater

Lower part: non-nervous part

Extends dorsally -->Dorsal Recess of 4th Ventricle (at the midline), extends into

white core of the cerebellum

Cerebello-medullary cistern (akacysterna magna)

Foramen of Mazendie: aperture in midline of roof

Roof

Diamond-shaped

Upper part --> Pons

Lower part --> Medulla

Striae medullarae fibers in between pons & medulla

Median sulcus divides the floor into 2 halves; vertically

Extends from Superior fovea (surface depression) caudally to another surface

depression --> Inferior fovea (depression on lower half)

Facial colliculus elevation that is opposite to superior fovea

Medially -->Medial eminence

Laterally -->Vestibular Area

Sulcus limitans divides each half of the ventricle

Floor

Audio recording started: 11:24 AM July-21-10 Ventricles

3rd & 4th VentriclesJuly-21-10

11:19 AM


55/63

Inter-thalamic space (in midl ine)Comm w/ lateral ventricle via interventricular foramen of Monroe

Comm w/ 4th ventricle via cerebral aqueduct

Formed by Tela choroideae of 3rd ventricle = double layer of pia mater

Fornix (choroid fissure bt thalamus and fornix)

Choroid plexus from lateral ventricle extends into 3rd ventricle via choroid fissure

Roof

Optic chiasma (most anterior)

Tuber cenarium

Infundibulum

Mamillary body

Posterior perforated substance

Pituitary gland

Floor

Primitive cranial end of neural tube

Anterior commissure:connects 2 olfactory areas

Lamina Terminalis invaded by anterior commisssure

Sloping area & 2nd column can't be seen (uvula between these columns)

Body of Fornix divides into 2 columns

Uvula: Small extension of 3rd ventricle beyond its space bt diverging columns of fornix

Anterior Wall

Hebelunar Commissure: thickening connecting 2 hebelunar nuclei

Upper part of stalk

If dmgd (ie: due to enlarged 3rd ventricle) --> no indirectl ight response

Posterior commissure --> pretectal f ibers for indirect light reflex

Lower part of stalk

Pineal gland att to wall via Pineal stalk(ventricle extends into stalk, dividing it into 2 parts)

Partially formed by tectum of midbrain

Posterior Wall

Lateral Wall (2)

3rd Ventricle

Contains modified neurons & astrocyte-l ike cells surr by fenestrated capillaries

Chemoreceptor Trigger Zone (CTZ): triggers vomiting in response to circulating emetic

substances

Plays a role in food intake & cardiovascular regulation

Area Postrema: 2 small subependymal oval areas on either side of 4th ventricle


56/63

Audio recording started: 11:11 AM July-26-10 Ventricles

Cont'd

Cavity of forebrain (Telencephalon) --> inverted C-shaped

Roof: corpus callosum

Medial Wall: septum pallucidum

Laterally -->head of caudate nucleus

Medially -->rostrum of corpus callosum

Floor:

Anterior Horn (frontal lobe) --> body projects forwards and lateral

Roof & Lateral Wall: retrolentiform part of internal capsule - -> fibers of optic radiation & tapetal fibers (don't

interdigitate w/ corona radiata)

Bulb: elevation formed by Forceps majorfibers from splenium of corpus callosum

Floor & Medial Wall :

Posterior Horn (occipital lobe) --> tail-like extension of body

Calcaralis elevation at junc'n bt posterior & inferior horns

tail of caudate nucleus --> continuous w/ amygdaloid complex

Striae terminalis fibers

Roof: covers medial & lateral side

hippocampus

Albius: white matter covering the hippocampus; has dentate gyrus

Collateral eminence: elevation produced by collateral sulcus in inferior surface of brain (classified as

complete sulcus)

Floor: covers medial & lateral side

Inferior Horn (temporal lobe) --> largest projection of body

pleasured area = part of limbic system

Bilaminar Septum Pallucidum: between both sides of lat ventricles; extends from inferior surface of corpus callosum

to body of fornix

"5th ventricle of the brain" bt 2 layers of septum pellucidum but NOT really a ventricle bc no ependymal lining -->

only has tissue fluid

Roof: formed by undersurface of body of corpus callosum

Striae terminalis - -> bundle of fibers = only efferent out of amygdaloid complex in groove between thalamus &

caudate nucleus

Thalamostriate vein also present in groove

Floor: thalamus in medial aspect & body of caudate nucleus in lateral aspect

Medial Wall: formed by septum pallucidum

May affect body of caudate nucleus --

Hydrocephalus --> extension of body of lateral ventricle

Body: extends from interventricular foramen of Monroe to splenium of corpus callosum

Lateral Ventricle

Very clear, colorless, odorless, water-like fluid (ultrafiltrate of plasma)

pH = 7.35, speci fic gravity = 1007, [protein] = 25 mg/dL (vs 1025 mg/dL in plasma)

very high [Na] & [Cl], low [K] & [Ca]

Lateral ventricle --> interventricular foramen of Monroe--> 3rd ventricle

3rd ventricle -->cerebral aqueduct --> 4th ventricle

4th ventricle - ->subarachnoid space

Formed by choroid plexus --> mainly in lateral ventricles, but also in 3rd & 4th ventricles

CSF Circulation

Lateral Ventricle & CSF CirculationJuly-26-10

11:04 AM


57/63

Impaired circulation & resorption of CSF

Aqueductal stenosis: most common cause; narrowing of cerebral aqueduct = enlargement of lateral & 3rd

ventricles bc lateral communicates with 3rd but comm bt 3rd & 4th is impaired

Blockage ofinterventricular foramen of Monroe

Obstruction ofcerebral cisterns (superior, cerebromedullary, lumbar, pontine, chiasmatic)

Obstructive (Non-Communicating): obstruction w/in ventricular system

Increased production of CSF due to choroid plexus papilloma

Venous thrombus: occlusion of outflow veins

Arachnoid villi inflammation: occlusion of arachnoid granulations

Subarachnoid hemorrhage: compression of outflow veins

Decreased reabsorption into venous system

Non-Obstructive (Communicating)

Sluggish pupil lary reaction

Absence of upward gaze

Impaired lateral gaze, nystagmus

Paralysis or spasm of convergence

Absence of visual fixation

Seizures

Optic N compressed due to increased CSF

Impairment of venous f low = impairment ofcentral retinal artery

Exopthalmos --> optic disk is choked --> Optic Nerve (CN II) is submerged in subarachnoid space

Scleral prominence from downward displacement of orbits

UMN signs

Children

HA, Lethargy, Malaise, Incoordination, Weakness

Ocular nerve palsies

Most commonly caused by brain tumors, subdural hematoma, hydrocephalus

Usually doesn`t alter visual acuity or result in visual field defects

Usually asymmetric & greater on side of supratentorial lesion

Foster-Kennedy Syndrome:results from meni ngioma of olfactory groove --> compresses olfactory

tract & optic nerve = ipsilateral anosmia, optic atrophy &contralateral papilledema

Papilledema (choked disk): noninflammatory congestion of optic disk caused by increased intracranial P

Ataxia

Corticospinal tract anomalies, UMN signs

Adults

Signs

Symptoms in adolescence or adult life --> headache, neck pain

NO Hydrocephalus

Type I: displacement of cerebellar tonsils into cervical canal

Elongation of 4th ventricle

Displacement of inferior vermis, pons & medulla into cervical canal bc there is a congenital

absence of the roof to the 4th ventricle

Type II: progressive hydrocephalus & myelomeningocele

Chiari malformation

Developmental failure of roof of 4th ventricle during embryogenesis

90% have hydrocephalus --> Enlarged occiput

Dandy-Walker Syndrome: cystic expansion of 4th ventricle in posterior cranial fossa

Tumors

Lesions or malformations of posterior fossa

IVH

Meningitis: Pneumococcal, TB

Intrauterine infections

Causes

Abnormally narrow aqueductus of sylv ius

Endangers body of caudate nucleus

Obstruction of cerebral aqueduct = enlargement of 3rd & lateral ventricles

Aqueductal stenosis (congenital stenosis of cerebral aqueduct)

Aqueductal gliosis: brisk, glial response of ependymal lining

Pathology

Hydrocephalus


58/63


Hydrocepha

lus

Bleeding in subependymal germinal matrix w/ or w/o ext into ventricles & brain

parenchyma (if w/ ext'n = communicating hydrocephalus)

Intravascular

Vascular

Extravascular

Pathology

Hydrocephalus (20% in moderate bleeds, 65-100% in large bleeds)

Complications

Avoid prolonged labor or difficult vaginal delivery

Avoid pneumothorax

Avoid hypo- or hypertension in neonate

Avoid hypoxic ischemic insult

Prevention

Children: Irritability, Poor feed, Lethargy, vomiting

Older pts: headache, change in personality, academic deterioration

Symptoms

Anterior fontanelle is wide open & bulging, increased head circumference

Dilated scalp veins

Sun-setting sign --> downward deviation of the eyes; occurs whenever there

is increased volume of head

Brisk tendon reflexes, spasticity

Clonus, Babinsky sign

Macewen sign "cracked-pot" --> enlargement

Prominent occiput (Dandy-Walker)

Signs

Separation of sutures

Erosion of posterior clinoids

Increased convolutional markings (beaten silver appearance)

X-ray plain films

Ultrasound

CT scan

MRI

Imaging studies

Medical:Acetazolamide, Furosemide

Surgical: V-P shunt placement

Therapy

Increased risk for developmental disabilities

Lower mean IQ compared to general population

Memory abnormalities

Some patients may show aggressive or delinquent behavior

Strabismus

Visuospatial abnormalities

Decreased visual acuity

Visual field defects

Visual problems

Patients require long term follow up (multidisciplinary)

Prognosis

Intraventricular Hemorrhage (IVH)

Hydrocephalus of ex-vacuo --> increased CSF w/o increasing intracranial P (occurs in

Alzheimer`s patients) = atrophy of brain

Causes of Hydrocephalus Cont`d

Diagnosis of Different Types of Hydrocephalus

Hydrocephalus Cont`dJuly-27-10

11:09 AM


59/63

Scored from 3 to 15 (3 = worst, 15 = best)

1 = no eye opening

2 = painful eye opening

3 = eye opening to verbal command

4 = eyes open spontaneously

Best eye response =max score of 4

1 = no verbal response

2 = incomprehensible sounds3 = inappropriate words

4 = confused

5 = orientated

Best verbal response =max score of 5

1 = no motor response

2 = painful extension

3 = painful flexion

4 = withdrawal from pain

5 = localized pain

6 = obeys command

Best motor response =max score of 6

3 Parameters

Glasgow Coma Scale Tool (GCS):quantifies level of consciousness after traumatic brain

injuries (steth not required)

Case 1

Abscess in right occipital lobe

With complaints of headache & a history of chronic ear infections, a 43 yo man was diagnosed

w/ papilledema, left homonymous hemianopia, altered mental status. There were no other

significant motor or sensory findings.


60/63

Audio recording started: 11:10 AM July-28-10 Spinal Cord

Lesions

Case

Causes: stab/gun shot injuries, ext ramedullary tumorsaffe cting side of

spinal cord; herniation of disc (aka spinal shock)

Above lesion --> no problems

LMNbc Common Pathway of Sherrington damaged

Atropy, areflexi a, atonia

At level of lesion

LCST --> hyperreflexia, spasticity

Reticulospinal tract (tone)- -> clasp-knife rigidity

UMN -->mainly dmg to l ateral corticospinal tract

Below lesion

Motor deficits

Above lesion

BILATERAL loss of pain & te mperature (syringomyelia)

At level of lesion

Ipsilate ral loss of touch, pressure, vibration &

conscious proprioception -->Rhomburg's sign (+)

Contralateral loss of pain & temp

Below lesion --> cdamage to poste rior column tracts

Sensory deficits

Symptoms

Complete Hemisection of spinal cord (Brown-Sequard Syndrome)

A 23 yo woman complained of pain in her right breast & progressive we akness of

her right lower li mb for many months; neuro exam = weakness in low er limb; assoc

w/ spasticity (increased tone), hy perreflexia (increased deep tendon re flexes) at

knee & ankle = clonus; right side = loss of 2-ot touch vibratory sense & proprio at

leve ls below hip. Le ft side showed a loss of pain & temp below dermatome T7

Syringomyelia --> LISTEN TO LECTURE

Syrnix --> cavity (can enlarge in any direction = differing symptoms)

MRI is only way to confirm diagnosis along w/ PE

Conus medullaris

Amyeotropic lateral sclerosis (ALS)

Multiple sclerosis

Quada Inguina

Bilateral loss of pain & temperature sensation

Injury above leve l of Phrenic N (C3,4,5) = DEATH due to resp arrest

Anything bel ow C3,4,5 = alive

As bladder is fill ed w/ urine until it reaches max tone, internal urethral

sphincter opens a little = dribbling (retention reflex)

Urinary incontinence (can't ctrl LMN to bladder) = no micturiti on reflex

Retention of fe ces in rectum (retention outflow)

Gunshot injury below cervical region

Bed sores --> skin ulcers

RECOVERY PERIOD AFTER SPINAL SHOCK = 2-4 WEEKS

In cases of Spi nal Shock:

Spinal Cord LesionsJuly-28-10

11:09 AM


61/63


Limbic

System

Series of structures around brain stem; medial side of brain

Emotions referred by lower centers (ie : hypothalamus) to cortex (consciousness)

"smell brain" = forebrain

Humans are microosmatic bc our forebrain is responsible for more functions not just

smell

Smell enhances GIT motility

Enhances sex search (more important in animals)

Enhances fear...

1837 --> R. Owen -->Rhinencephalon (entire forebrain = olfactory in macroosmatic

animals, ie: dogs)

Limbic System

Papez Circuit--> responsible for recent memories and past experiences

Peripheral fibers = receptors

Central process pierces cribriform plate of ethmoid bone --> bulb

Olfactory mucosa --> in roof of nasal cavity (bipolar)

Mitral Cells

Tufted Cells

Bulb (6 layers)

Medial olfactory gyrus: gray matter that accompanies striae

Few fibers pass through Ant. Commissure --> opposite side ofcortex

Some fibers end up below/sub-callosum -->paraterminal gyrus

Medial Striae --> traverses w/ ant commissure & goes to opposite side

Intermediate Striae --> anterior perforated substance

Lateral olfactory gyrus: Band of gray matter that

accompanies striae; continuous with gyrus ambience

Both gyri continuous with Entorhinal Area (Area 28) --> part

of parahippocampal gyrus (part of corticomedial division of

amygdaloid complex)

Pyriform lobe

Lateral Striae --&

Documents

Neuro Notes 63 Pages