Higher Brain Centers Anatomy

Cerebellum Location

Dorsal to the brainstem; separated from the brainstem by the 4th ventricle

Cerebellum function

Movement; motor coordination, error correction, motor learning, timing of movements

Diencephalon Components

Thalamus and Hypothalamus

Thalamus Structure

Two egg shaped structures (one in each hemisphere)

Thalamus location

Located near the midline at the base of the brain; one on either side of the 3rd ventricle

Thalamus function

• contains thalamic nuclei

• Projects to and feedback projections from the cortex

• Sends sensory information to primary sensory cortices

Hypothalamus location

Ventral to the thalamus, near the bottom of the 3rd ventricle; attached to the pituitary gland along its ventral surface

Hypothalamus function

Contains small nuclei; regulates hormone release from the pituitary gland; major visceral motor center that regulates the autonomic NS (“head ganglion”)

Basal Ganglia Location

Inferior and medial to the cerebral cortex, lateral to the diencephelon

Basal ganglia make-up

Composed of interconnected groups of neurons called “ganglia”

Basal ganglia shape

Caudate nucleus (part of the basal ganglia) curves in a backwards “C” shape

Basal ganglia function

Motor planning/gating

Cerebral cortex divisions

Frontal, parietal, temporal, occipital, and insular (all are part of the telencephelon, named after the bones of the skull that fused during development (except for the insular cortex))

Sulci definition

Shallow folds in the cerebral cortex

Fissures definition

sulci folds that are deeper

Longitudinal fissure

Divides the cerebral cortex into two halves, creating 2 hemispheres

Lateral fissure

Separates the temporal lobe from the front and parietal lobe

Where is the insula?

Since the cortex of the lateral fissure is so deep, it’s held within its depths

Gyri/Gyrus

Rounded regions between the Sulci

Sutures

separate the bone (plates) of the skull

Name the sutures of the skull

Coronal, Sagittal, Lamboid, Squamous

Coronal Suture

Separates the frontal and parietal bones (“crown”)

Sagittal Suture

Lies along the midline and separates the two parietal bones

Lamboid Suture

Separates the parietal and occipital bones (named after Greek Lambda )

Squamous Suture

Separates the temporal bone from the parietal bone (temporalis = temple)

Types of cortical areas

Primary and association

Describe primary sensory cortices

Receive sensory input from the thalamus and association cortices (olfactory does not receive this information); involved in early processing of sensory input

Types of primary sensory cortices

Primary visual cortex, primary somatosensory cortex, primary auditory cortex, primary olfactory cortex, primary gustatory (taste) cortex

Describe primary motor cortex

Sends motor commands to the lower areas of the motor system

Describe association areas

Send and receive information only from other cortical areas; involved in higher order sensory, motor, and cognitive functions

Occipital lobe location

Back of the brain, below the parietal lobe and above the cerebellum

Primary cortex of the occipital lobe

Primary visual cortex

Function of the occipital lobe

Primary cortex is Organized as a “map” of the retina; association cortices involved in visual processing at earlier stages than parietal lobe

Primary cortex of the parietal lobe

Primary somatosensory cortex

Parietal cortex location

Located in the post-central gyrus, caudal to the central sulcus

Function of the parietal lobe

Organized topographically (somatosensory homunculus); somatosensory input to each hemisphere come from the contra lateral side of the body

Describe the association cortex of the parietal lobe

Posterior parietal cortex includes multiple association cortices, including those involved in high-level visual processing, and perception of spacial organization

Primary cortex of the frontal lobe

primary motor cortex

Primary motor cortex location

in the precentral gyrus, rostral to the central sulcus

Motor cortex organization

organized topographically; “motor homunculus”; the amount of cortical tissue for a given region of the body is proportional to the number of motor neurons used to control that region

Motor cortex function

controls voluntary movements of the contralateral body

Association areas of the frontal lobe

broca’s area (language); multiple divisions of the prefrontal cortex are involved in functions such as long-term planning, working memory, and judgement

Describe the corpus callosum

axons that cross the midline to connect the two cerebral hemispheres

Temporal Lobe Location

ventral side of the brain, below parietal lobe

Primary cortex of the temporal lobe

primary auditory cortex (organized according to the pitch of sounds)

Association Cortices in the temporal lobe

Wernicke’s area (critical for language); areas involved in recognizing objects and people, areas involved in memory

Insular lobe location

Located inside the lateral fissure

Primary cortex for the insula

gustatory cortex, involved in taste

Insular lobe function

taste and receiving visceral sensory inputs