Module 3: Gross anatomy of the Brain

What do human and animal brains have in common

• Brain areas

• Connections between brain areas

• Types of neurons & glia

• Chemicals (neurotransmitters)

• Proteins (channels & receptors)

• Signaling molecules

How are human and animal brains different

• Overall brain size

• Size/development of individual parts

What are the four main lobes

frontal, occipital, temporal, parietal

lateral fissure

the most prominent deep groove on the surface of the human brain

longitudinal fissure

separates left and right hemispheres

do the two hemispheres touch

no

central sulcus

separates frontal lobe fron parietal lobe

three major divisions of the brain

forebrain, midbrain, hindbrain

brainstem includes

midbrain, pons, medulla

the cerebellum is part of the...

hindbrain

brain stem is responsible for

breathing, consciousness, blood pressure, heart rate, and sleep

medulla

controls vital reflexes (breathing, heart rate) and some cranial nerves

what could be fatal

damage to the medulla

pons

- bridge connecting the cerebrum (forebrain) and the cerebellum

- source of sensory nerves and motor cranial nerves

- involuntary functions like breathing, sleep cycles, facial expressions

midbrain

• Smaller but critically important

• Reflexive orienting to visual and auditory stimuli

• Intrinsic, descending pain control system

• 2 major sources of dopamine housed here

cerebellum

- part of hindbrain, posterior to the brainstem

- involved in movement and coordination

- well-learned movements

- balance and postural control

hindbrain

- most posterior of the 3 brain vesicles formed during development

- lower back part of the brain

hindbrain includes

medulla, pons, cerebellum

largest region of the brain

forebrain

forebrain

responsible for cognition, emotion, voluntary behavior

what does the forebrain include

cerebral cortex, corpus callosum, thalamus, hypothalamus, pineal gland, pituitary gland, basal ganglia, limbic system

cerebral cortex

- wrinkled, gray matter outer layer

- responsible for memory, language, consciousness, voluntary movement

Gyri

folds

sulci

grooves

4 lobes of the cerebral cortex

frontal, parietal, occipital, temporal

the cerebral cortex includes

frontal lobe, parietal lobe, occipital lobe, temporal lobe, central sulcus, lateral fissure, longitudinal fissure

corpus callosum

huge bundle of axons that connects the 2 hemispheres of cortex

thalamus

- contains many nuclei

- replay station/filter for sensory info on its way to cortex

hypothalamus

involved in drive-related behaviors and maintenance of homeostasis: feeding, drinking, sexual behavior, temp regulation...

pituitary gland

hormone producing gland found at the base of the hypothalamus and controlled by the hypothalamus

pineal gland

makes and secretes melatonin

occipital and temporal lobe

major visual and auditory processing hubs

occipital lobe

vision and primary visual cortex

temporal lobe

primary auditory cortex, Wernike's area, visual association cortex

parietal labe

top, back of head, major sensory processing hub, primary somatosensory cortex

frontal lobe

control center, executive function, motor control, language, Broca's area

Meninges and Ventricles

protects our brain

The 3 meninges

pia mater, arachnoid mater, dura mater

pia mater

thin layer covering the cerebral cortex

arachnoid mater

spider web like layer with arteries and veins

dura mater

most durable and leathery

above meninges

skull, then scalp

Cerebrospinal fluid

• Choroid plexus of lateral

ventricles creates the CSF

by filtering blood

• Glymphatic system is a

"lymphatic system"

implemented by glial cells

where waste is carried to the

CSF and drained from the

brain

Hydrocephalus

• Too much CSF is

generated or

cannot be drained

• Mixed symptoms

and associations

with various

neurological and

psychiatric illness

Disorders of the Meninges

• Meningitis: infection in the

brain that can be measured in

the cerebral spinal fluid

• Subarachnoid hemorrhage:

most lethal kind of stroke

where an artery fill the

subarachnoid space with

blood

• Meningiomas: tumor that

grows in the meninges.

Typical benign and can be

removed or left alone.

Limbic System

network of structures know as "emotional nervous system"

Limbic system core functions

feeding, feeling (flight, fight), fing (reproduction)

Limbic structures

hippocampus, amygdala, fornix, cingulate, thalamus, hypothalamus, olfactory bulb

Hippocampus

• Shaped like/means "seahorse"

• Deep within temporal lobe

• Long-term memories

(facts/events)

• Spatial navigation

• Learning

• And of course, emotion

Amygdala

• Almond-shaped

• Also deep within the temporal lobe

• One in each hemisphere

• Sits just in front of the hippocampus

• Hub for processing emotions like

fear, anxiety, and pleasure

• Attaches emotional significance to

memories

thalamus

• Means "inner chamber"

• "Small brain" at the center of

the brain

• Connections to all over the

cerebral cortex (lots of nuclei)

• Relay station/ filter for sensory

info on its way to cortex

• Involved in many other systems

(motor, emotional, memory,

etc.)

Cingulate Gyrus

• Arch-shaped strip of cortex atop

corpus collosum

• Also deep within the temporal lobe

• One in each hemisphere

• Sits just in front of the hippocampus

• Frontal

• Directing attention

• Emotional processing

• Connects sensory input to emotions

• Emotional responses to pain

• Learning

• Pain perception

fornix

• C-shaped bundle of white matter fibers

(name means "arch")

• Located on the medial (inner) side of each

hemisphere, arching around thalamus

• Connects hippocampus to areas like the

thalami

• Crucial for memory, emotion, learning

• Damage can cause serious memory loss

• Main output tract for hippocampal info -

vital in recalling long-term memories

• Its pathology is linked to AD, epilepsy, +

cognitive aging, so target for

research/potential therapies

olfactory bulb

• Process and relay smell from nose

to brain

• Links scents to memories

• One of the few regions where new

neurons are generated throughout

life (neurogenesis)

basal ganglia function

control and modulate

voluntary movement

basal ganglia (subcortical)

• Dorsal striatum:

caudate & putamen

• Ventral striatum:

globus pallidus

• Close connection to

thalamus and

prefrontal cortex for

the control over

movement