Intro to Neuro - Brain and Spinal Cord Anatomy

Lecture 2

White Matter

myelinated axons

gray matter

mostly cell bodies and dendrites

Spinal cord

Located within the vertebral column

• Transfers information between CNS and PNS

• Pairs of spinal nerves are attached to the cord at 31 different

levels. Spinal nerves are either sensory or motor.

• Sensory information enters the dorsal (back) portion, and

motor commands exit on the ventral (stomach) side.

• Ganglion – collection of somas

• Root – axons entering and exiting the spinal cord

Medulla

Includes neurons that maintain normal, rhythmic breathing

Pons Region

Includes axons that allow the cerebellum to communicate with the brainstem and the cerebral cortex. The fourth ventricle is on the dorsal side

Midbrain

Superior and inferior colliculi: localization of visual and auditory stimuli

Cerebellum

Motor planning:

• Aids the motor cortices in planning

complex movements

Motor learning:

• Error correction when learning

movements: compares intended

movement with actual movement and

corrects errors that might occur

• Synapses change with experience

Diencephalon

Thalamus:

• Located rostral to the midbrain

• “Relay” for information going to and

coming from the neocortex

Hypothalamus:

• Located below the thalamus

• Regulates the autonomic nervous system

• Regulates hormone release

Cerebral cortex (a.k.a. neocortex) - structure

Gross structures:

• Sulci (singular: sulcus): grooves

• Fissures: deep sulci

• Gyri (singular: gyrus): rounded regions

between sulci

Cerebral cortex (a.k.a. neocortex) - function

Functions:

• Processing of sensory input

• Initiation/planning of movements

• “Higher-order” functions including

memory, cognition, language

Lobes of the cerebral cortex

• Occipital lobe

• Parietal lobe

• Temporal lobe

• Frontal lobe

Central sulcus:

separates parietal and frontal lobes

Lateral Fissure

Separates the temporal lobe from those surrounding it

Longitudinal Fissure

Separates the two hemispheres of the brain

Postcentral gyrus

• Directly caudal to the central

sulcus

• Contains the primary

somatosensory cortex, which

processes touch and pain

information

Precentral gyrus

• Directly rostral to the central sulcus

• Contains the primary motor cortex,

which helps plan movements and

sends motor (movement) signals to

the spinal cord

Occipital lobe

Early stages of vision

Parietal lobe

touch and pain, late-stage vision

temporal lobe

memory, hearing, language comprehension

Frontal Lobe

• Planning and signaling movements

• Working memory

• Inhibition of inappropriate behaviors

• Planning

Limbic System

A group of interconnected

structures that are related to

emotional behavior and emotional

interpretation of the world.

• Sexual behavior

• Involved in the formation of

memory, contains primary reward

and punishment centers.

• Site of action of drugs which

produce euphoria (direct and

indirect)

Hypothalamus - limbic system

• Regulates many

motivated functions (e.g.,

eating and drinking),

sleep/wake cycle

• Controls activity of the

pituitary gland (master

gland that interacts with

the hypothalamus to

regulate many functions

via the release of

hormones)

Hippocampus - limbic system

Memory consolidation and providing organism’s context

Amygdala - limbic system

Coordinates autonomic responses in with emotional states

Cerebral cortex - limbic system

Interacts with subcortical structures to guide behavior

Basal Ganglia

Group of interconnected structures

that control voluntary, smooth movement

Structures include:

striatum (caudate/putamen)

globus pallidus

substantia nigra

Actions of stimulants in the

basal ganglia increases motor

activity

Corpus callosum

Long range of neurons that connect the two different halves of the brain