CRANIAL NERVE NUCLEI - LECTURE A

NBIO 401 – Wednesday, October 3, 2012

Objective for the first two cranial nerve lectures, those about cranial nerve nuclei:

-Be able to summarize the function and location of each cranial nerve nucleus.

Cranial Nerve Nuclei Introductory

Organization

V

VI

VII

VIII

IXX

XII

III

I

Optic Nerve II

V

VI

VII

VIII

IXX

XII

III

I

Optic Nerve IIONLY III - XII

V

VI

VII

VIII

IXX

XII

III

I

Optic Nerve IICRANIAL NERVE NUCLEI A = III - V

V

VI

VII

VIII

IXX

XII

III

I

Optic Nerve II

CRANIAL NERVE NUCLEI B = VI - XII

MesencephalicTrigeminal V

(jaw muscle spindles)

Main SensoryTrigeminal V

(face touch & proprioception)

Spinal Trigeminal V(face pain)

Vestibular/Cochlear

VIII(vestibular & auditory

signals from the inner ear)

Oculomotor III(eye muscles)

Trochlear IV(eye muscles)

Abducens VI(eye muscles)

Hypoglossal XII(tongue muscles)

SensoryGSA and SSA

MotorGSE

GENERAL SOMATICCRANIAL NERVE NUCLEI

Solitarius (caudal half)VII, IX, X

(sensory informationfor autonomic control)

Edinger-Westphal III(constricts pupil - parasympathetic)

Superior salivatory VII(drives salivary glands -

parasympathetic)

Inferior salivatory IX(drives salivary glands -

parasympathetic)

Dorsal motor n. of X(parasympathetic drive tosmooth muscles & organs

in chest and abdomen)

SensoryGVA

MotorGVE

GENERAL VISCERALCRANIAL NERVE NUCLEI

Solitarius (rostral half)VII, IX, X

(taste)

Motor Trigeminal V(chewing muscles)

Facial VII(muscles of

facial expression)

n. Ambiguus IX, X(muscles of the

pharynx & larynx)

SensorySVA

MotorSVE

SPECIAL VISCERALCRANIAL NERVE NUCLEI

sulcus limitans(divides motor nuclei [medial] and

sensory nuclei (lateral]).

sulcus limitans(divides motor nuclei [medial] and sensory nuclei (lateral]).

sulcus limitans

Motor nuclei locations

General Somatic Efferents lie close to the midline

General Visceral Efferents lay laterally to the General Somatic Efferents

Cranial Nerve Nuclei III-V

The Oculomotor (IIIrd) Nucleus

Oculomotor nucleus(motoneurons for

eye muscles)

Oculomotor nerve(to eye muscles & pupil muscles)

Edinger Westphal nucleus(constricts the pupil)

General Somatic Efferents lie close to the midline

MesencephalicTrigeminal V

(jaw muscle spindles)

Main SensoryTrigeminal V

(face touch & proprioception)

Spinal Trigeminal V(face pain)

Vestibular/Cochlear

VIII(vestibular & auditory

signals from the inner ear)

Oculomotor III(eye muscles)

Trochlear IV(eye muscles)

Abducens VI(eye muscles)

Hypoglossal XII(tongue muscles)

SensoryGSA and SSA

MotorGSE

GENERAL SOMATICCRANIAL NERVE NUCLEI

Cranial Nerve Nuclei

The Trochlear (IVth) Nucleus

QuickTime™ and aGIF decompressor

are needed to see this picture.Trochlear nerve(to eye muscles)

Trochlear nucleus(motoneurons for

eye muscles)

General Somatic Efferents lie close to the midline

MesencephalicTrigeminal V

(jaw muscle spindles)

Main SensoryTrigeminal V

(face touch & proprioception)

Spinal Trigeminal V(face pain)

Vestibular/Cochlear

VIII(vestibular & auditory

signals from the inner ear)

Oculomotor III(eye muscles)

Trochlear IV(eye muscles)

Abducens VI(eye muscles)

Hypoglossal XII(tongue muscles)

SensoryGSA and SSA

MotorGSE

GENERAL SOMATICCRANIAL NERVE NUCLEI

Cranial Nerve Nuclei III-V The

Trigeminal Nuclei

SensoryAxons signals for conscious

touch & muscle spindle/joint receptors(cell body in ganglion outside CNS)

SensoryAxons of 1° sensory neuron

for unconscious musclespindle & joint receptors

(cell body in mesencephalictrigeminal nucleus - the only

1° sensory cell body inside CNS)

To Thalamus

SensoryAxons signals for pain & temperature(cell body in ganglion outside CNS)

MotorAxons carrying motor signals to jaw muscles

(cell body motor trigeminal nucleus)

Trigeminal nerve

(sensory & motor

axons of 4 types

listed to the right)

Mesencephalic trigeminal nucleus (1° sensory neurons for

muscle spindles &joint receptors in head)

Mesencephalic trigeminal tract (axons bringing

unconscioussignals from muscle

spindles & joints in head)

Main sensorytrigeminal nucleus

Trigeminal nerve

Spinaltrigeminalnucleus

Motortrigeminalnucleus

Spinal trigeminal nucleus(pain & temperature from head)

Motor trigeminal nucleus(motoneurons for jaw muscles)

Main sensory trigeminal nucleus(touch, conscious

spindle & joint from head)

Trigeminal nerve(afferent: touch, muscle spindle/joint,

pain & temperature from headefferent: chewing muscles)

Main sensorytrigeminal nucleus

(left)

MotorTrigeminal

Nucleus(right)

Mesencephalic trigeminal tract

(left)

Mesencephalictrigeminal nucleus

(left)

Spinal trigeminal nerve (left)(1° axons on way to

terminate inspinal trigeminal nucleus)

Main sensorytrigeminal nucleus

(right)

SpinalTrigeminal

Nucleus(right)

TrigeminalNerve(left)

TrigeminalNerve(right)

Spinal trigeminal nucleus

(left)

Special Visceral (Branchial) Efferents lie most lateral of the motor nuclei.

Solitarius (rostral half)VII, IX, X

(taste)

Motor Trigeminal V(chewing muscles)

Facial VII(muscles of

facial expression)

n. Ambiguus IX, X(muscles of the

pharynx & larynx)

SensorySVA

MotorSVE

SPECIAL VISCERALCRANIAL NERVE NUCLEI

Mediallemniscus

Spinothalamictract

PyramidalTract

MedialLongitudinalFasciculus

PontineGray matter

SuperiorCerebellarpeduncle

Mesencephalic trigeminaltract & nucleus

ROSTRAL PONS

Mediallemniscus

Spinothalamictract

PyramidalTract

MiddleCerebellarpeduncle

MLF

PontineGray matter

Motor trigeminalnucleus

Superior cerebellar peduncle

Trigeminal nerve( sensory & motor

for the head)

Mesencephalic trigeminal tract & nucleus(muscle spindles from chewing muscles

& jaw joint receptors)

MID PONS

Mediallemniscus

Spinothalamictract

PyramidalTract

MiddleCerebellarpeduncle

MLF

PontineGray matter

Superior cerebellar peduncle(fibers coming out of cerebellum)

Main sensory trigeminalNucleus (face touch)

Motor nucleusof trigeminal

(chewing musclemotoneurons)

Spinal trigeminaltract & nucleus

MID PONS

Mediallemniscus

SpinothalamicTract

PyramidalTract

Spinal trigeminalnucleus & tract

Abducens Nucleus(eye muscle

motoneurons)

Vestibularnuclei

MiddleCerebellarpeduncle

MLF

PontineGray matter

Inferiorcerebellarpeduncle

Facial nerve fibers(looping around abducens nucleus)

Facial motornucleus

CAUDAL PONS

Cuneate Fasciculus(touch-arm)

Pyramidal Decussation(corticospinal fiberscrossing midline)

SpinothalamicTract

(body pain)

Spinocerebellar Tract(sensory fibers - Muscle

spindle& joint information to

cerebellum - leg)Pyramids(corticospinal fibers)

Spinaltrigeminal

nucleus & tract(head pain & temp)

Cuneate Nucleus

(touch-arm)

Gracile Nucleus

(touch-leg)

Gracile Fasciculus(touch-leg)

Centralcanal

Medial LongitudinalFasciculus (MLF)

(vestibular & oculomotor information)

Spinal AccessoryNucleus

(motoneurons fortrapezius &

sternocleidomastoidmuscles)

Fini