The Brain

Four Parts of Brain

Cerebrum, Diencephalon, Cerebellum, Brain Stem

Cerebrum

Divided into two halves, R + L, by longitudinal fissure

each hemisphere has 5 lobes; frontal, parietal, temporal, occipital, insula

Cerebral Cortex- location, gyri, sulci

Outer layer of cerebrum- made of grey matter, appears wrinkled

Gyri- squiggles on the outside

• precentral gyrus; anterior to central sulcus

• postcentral gyrus; posterior to central sulcus

sulci- grooves/ furrows between gyri

• central sulcus

• parieto-occipital sulcus

Functional regions- 3 types

Sensory regions- conscious awareness of sensation

Association areas- integrating information

Motor areas- voluntary motor function

Primary somatosensory cortex

location- postcentral gyrus

receives info from somatic senses ex; touch

enables conscious awareness of these senses

Auditory and Visual Cortices

Primary Visual Cortex

• Location: posterior/ medial occipital lobe

• receive visual information from retina of eye

Auditory Cortex

• location: temporal lobe

• Receives and processes auditory information from inner ear

Primary motor Cortex

Location: Precentral gyrus

Controls voluntary skeletal muscle activity

Cortical Homunculus

Neurological map of areas and portions of cortex dedicated to processing motor and/or sensory functions

Motor homunculus

Sensory homunculus

Broca’s and Wernicke’s area

Left hemisphere only

Broca’s area

• location: Left frontal cortex

• Motor speech control- speaking fluently

Wernicke’s area

• Location: parts of left temporal and parietal lobes

• Multimodal association area- comprehending speech and writing

Subcortical Structures- White matter structures

Commissure- region where structures are joined

Cerebral commissures- where L and R cerebral hemispheres are joined together

Corpus Callosum

Association fibers- short fibers that connect to regions in the same hemisphere

Deep grey matter of cerebrum

Subcortical (aka basal nuclei/ basal ganglia) nuclei

Generally cerebral nuclei involved in motor control stop and regulate intensity of voluntary movements

• caudate nucleus

• putamen

• amygdala

• globus pallidus