BASIC NEUROANATOMY & NEUROPHYSIOLOGY

Central nervous system (CNS): command-and-control network, consists of brain and spinal cord.

[vs. Peripheral nervous system (PNS) - courier network, consists of sensory receptors & motor effectors].

• Organized in layers: Gray matter (neuronal cell bodies) & white matter (axons & glial cells)

• Gross anatomy of the Brain: Major structures in forebrain, midbrain & hindbrain, and their functions.

o Midbrain: nuclei including superior and inferior colliculi, and substantia nigra; Controls respiration, states of

consciousness

o Hindbrain:

• Medulla oblongata: respiration, heart rate and blood pressure. Damage can be fatal.

• Pons: connective bridge from the rest of the brain to the cerebellum. Sleep, arousal, respiration, control of eye

and body movements

• Cerebellum: coordination of voluntary motor movements, balance & posture. Damage affects precision of

movement, disrupts balance and affects equilibrium.

Brainstem: Medulla (Oblongata), Pons, and Midbrain. Controls respiration and global states of consciousness, such as

sleep and wakefulness. Damage is life threatening.

o Forebrain: Telencephalon & Diencephalon

Diencephalon:

• Thalamus: relay center between all the sensory organs (except smell) and the cortex. The “gateway to the

cortex”

• Hypothalamus: regulating bodily functions/needs such as temperature, eating and drinking, sexual activity, and

regulation of endocrine functions

Telencephalon:

• Cerebral cortex

o Frontal lobe

o Parietal lobe

o Occipital lobe

o Temporal lobe

• Limbic system: cingulate gyrus, hippocampus, amygdala, mammillary bodies; involved in

emotions, learning, and memory

• Basal ganglia: caudate nucleus, putamen, globus pallidus, nucleus accumbens; involved in

action selection, reward-based learning, eye movements, cognition, motivation, and reward

THE CEREBRAL CORTEX

Outer layer of gray matter (composed mostly of the cell bodies of neurons and their local

connections) surrounding the inner white matter (composed of long-range myelinated tracts).

Gyri: elevated ridges “winding” around the brain

Sulci: small grooves dividing the gyri

Fissures: Deep sulci, generally dividing large regions/lobes of the brain

Roles of brain convolutions: allow more cortical surface to be packed inside the skull & brings neurons closer to each other

Major landmarks delineating the lobes:

• Central sulcus, separates the frontal lobe from parietal lobe;

• Lateral Sulcus or Sylvian fissure, separates the temporal lobe from the frontal and parietal lobes.

• Parieto-occipital Sulcus, separates the occipital from the parietal and temporal lobes

• Interhemispheric Fissure, also called the Longitudinal Fissure, separates the left and the right hemispheres

Cerebral cortex lobes:

Frontal lobe:

o Prefrontal cortex: anterior part of the frontal lobe. Executive function, higher

level of cognitive, emotional, and visceral integration.

o Motor cortex: Planning and execution of movements

▪ Topographic correspondence with unequal representation, reflecting

the contralateral body.

Parietal lobe:

o Somatosensory cortex (sensory information) & association areas (proprioception, spatial perception, etc.)

o Primary sensory cortex

Occipital lobe: processing, integrating, and interpreting visual stimulation

Temporal lobe: auditory processing, memory, visual recognition, and emotion

Communication between hemispheres

• Types of white matter fibers:

o Homotopic, heterotopic, ipsilateral

• Corpus Callosum: major white matter connection between hemispheres, allows each

hemisphere to access information from both sides