• 3 primary divisions:– Forebrain

• cortex (folded stuff)• limbic system, etc (stuff around brain stem)

– Midbrain (top of brainstem)

– Hindbrain (bottom of brainstem + cerebellum)

The Brain

Hindbrain

Medulla

Pons

Cerebellum

http://www-unix.oit.umass.edu/~psyc335c/lectures/hindbrain.gif

Pons

MedullaCerebellum

Medulla:Controls vital reflexes: breathing, heart rate, vomiting, salivation, coughing, sneezing

- Via cranial nerves

Damage to medulla can be fatal

Large doses of opiates can be fatal b/c suppress activity of medulla…why…?...b/c receptors there!

Pons:Also has cranial nerves

Location of axon decussation (where axons cross from one side of the brain to the other…so left brain controls right body and vice versa)

Reticular formation: motor control, arousal, consciousness

Midbrain:Cerebral aqueduct

More cranial nerves

Superior colliculus (visual info)

Inferior colliculus (auditory info)

Substantia nigra: dopamine-producing cells, structure that is lost in Parkinson’s Disease

http://en.wikipedia.org/wiki/Midbrain

BrainstemMedulla

Pons

Midbrain

Some forebrain structures

Senses: Information comes in the cranial nerves and eventually ends up in the cortex

Cranial Nerves

http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

Table 4.4, page 87

Olfactory nerve:

Smell

Cranial Nerves

http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

Table 4.4, page 87

Optic nerve:

Vision

Cranial Nerves

http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

Table 4.4, page 87

Occulomotor nerve:

Eye movement, pupil constriction

Cranial Nerves

http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

Table 4.4, page 87

Trochlear nerve:

Eye movement

Cranial Nerves

http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

Table 4.4, page 87

Trigeminal nerve:

Skin senses from face

Jaw muscles for chewing and swallowing (muscles of mastication)

Cranial Nerves

http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

Table 4.4, page 87

Abducens nerve:

Eye movements

Cranial Nerves

http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

Table 4.4, page 87

Facial nerve:

Taste

Facial expressions

Crying

Salivation

Dilation of head’s blood vessels

Cranial Nerves

http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

Table 4.4, page 87

Acoustic nerve:

Aka vestibulocochlear or statoacoustic

Hearing

Equilibrium

Cranial Nerves

http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

Table 4.4, page 87

Glossopharyngeal nerve:

Taste

Swallowing

Salivation

Throat movements during speech

Cranial Nerves

http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

Table 4.4, page 87

Vagus nerve:

Sensation from neck and thorax

Control of throat, esophagus, larynx

Parasympathetic nerves to stomach, intestines, etc

Cranial Nerves

http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

Table 4.4, page 87

Spinal accessory nerve:

Aka Accessory nerve

Neck and shoulder movements

Cranial Nerves

http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

Table 4.4, page 87

Hypoglossal nerve:

Muscles of tongue

Cranial nerve signs help determine the location of a lesion in the brain

• Essential element in clinical neuroanatomy

• Neurological exam: http://www.vhct.org/case1799/neurologic_examination.shtml

• Example: patient is asked to stick out tongue. If the tongue deviates to the left, the lesion involves the nucleus of the left hypoglossal nerve.

Nerve key Nerve Type of function

On Optic Some = sensory

Old Olfactory Say

Olympus Occulomotor Marry = motor

Towering Trochlear Money

Tops Trigeminal But = both (S&M)

A Abducens My

Fin Facial Brother

And Acoustic* Says

German Glossopharyngeal Bad

Viewed Vagus Boys

Some Spinal accessory** Marry

Hops Hypoglossal Money

* Acoustic-vestibulocochlear, stateocochlear

** Spinal accessory = accessory

Forebrain

• Thalamus

• Hypothalamus

• Pituitary gland

• Basal ganglia

• Basal forebrain

• Hippocampus

• Limbic system

Thalamus:

Relay station for all sensory info on its way to brain (except olfactory info)

Many specialized nuclei (ex: LGN, MGN…don’t have to know these!)

Hypothalamus

Communicates with pituitary gland to alter hormone release

Involved in feeding, drinking, temperature regulation, sexual behavior, fighting, arousal (activity level)…4 Fs

Pituitary gland

Endocrine gland (hormone producing)

Attached to base of hypothalamus by stalk

Makes and releases hormones into bloodstream

http://www.uni.edu/walsh/basalganglia-2.jpg

Basal Ganglia

Motor control, but also memory and emotional expression

Lose dopamine neurons in SN Parkinson’s Disease

Lose dopamine neurons in caudate & putamen Huntington’s chorea

thalamus.wustl.edu/ course/cbell6.gif

Don’t memorize image!!! Just understand that this is a very complex system!

http://memorylossonline.com/summer2003/glossary/basalforebrain.jpg

Basal forebrain

Anterior and dorsal to hypothalamus

Important for arousal, wakefulness, attention

Lose cells in nucleus basalis decreased attention & intellect (AD, PD)

http://www.hermes-press.com/Perennial_Tradition/hippocampus.gif

Hippocampus

Memory formation

HM: temporal lobes removed for intractable epilepsy no longer formed new memories

http://www.umassmed.edu/bnri/graphics/crusiofig1.gif

important for motivated & emotional behaviors (eating, drinking, sexual activity, aggressive behavior)

Limbic System

Ventricles

http://mywebpages.comcast.net/epollak/PSY255_pix/ventricles.PNG

Contain cerebrospinal fluid (CSF)

CSF reabsorbed into blood vessels, so continuous turnover

Protective

Reservoir for hormones, nutrients

Ventricle size can indicate problems

• Enlarged ventricles as in Alzheimer’s patients (cell loss).

• Lack of ventricles due to tumors etc.

Cortex• 2 hemispheres

– Communicate via corpus callosum & anterior commisure

• 4 lobes

http://pegasus.cc.ucf.edu/~Brainmd1/brmodelc.gif

http://www.urmc.rochester.edu/neuroslides/slides/slide201.jpghttp://trc.ucdavis.edu/mjguinan/apc100/modules/Nervous/grosscns/images/brain10.jpg

6 laminae (layers of cells)

The lobes of the cortex• Frontal

– Thinking– Prefrontal cortex

• Planning• Working memory• Socially appropriate

behavior• Delayed-response

task • Lobotomies

– Primary motor cortex

• Broca’s aphasia

The lobes of the cortex

• Parietal– Sensing

• Primary sensory cortex

Homunculus

The lobes of the cortex• Temporal

– Spoken language comprehension

• Wernike’s aphasia

– Hearing– Vision

• Movement perception

• Face recognition

– Emotional motivational behavior

The lobes of the cortex

• Occipital – Vision

• Primary visual cortex

• Damage causes “cortical blindness”

Evolution of Gene Related to Brain's Growth

• A gene that helps determine the size of the human brain has been under intense Darwinian pressure in the last few million years.

• It has changed its structure 15 times since humans and chimps separated from their common ancestor.

• Evolution has been particularly intense in the five million years since humans split from chimpanzees

Changes in the architecture of the ASPM protein over the last 18 million years are correlated with a steady increase in the size of the cerebral cortex (2002) Dr. Bruce T. Lahn at U. Chicago. A disrupted form of this gene was identified as the cause of microcephaly (people born with an abnormally small cerebral cortex).

Functions

• Forebrain– the cool stuff (thinking, perceiving, big part of emotion)

• Midbrain– sensory pathways

• Hindbrain– motor control, reflexes (breathing, heart rate, etc)