Cerebellum, Cranial Nerves, WM, and Blood Supply

Cerebellum Function

motor regulation and balance control

Cerebellum Limitation

unable to initiate muscle contraction

Cerebellar Structures

two hemispheres, three lobes, three fissues

Cerebellar Lobes

Anterior, posterior (largest), flocculonodular (smallest)

Primary Fissure

divides anterior and posterior lobe

Posterolateral Fissue

divides posterior and flocculonodular lobe

Horizonal Fissure

divides superior and inferior surfaces

Grey Matter of Cerebellum

(superficial) molecular → purkinje → granular (deep)

White matter of cerebellum

deep to grey matter

Cerebellum Input

from cortex and other cerebellar tracts

Cerebellum Layering (superficial to deep)

GM → WM → Central Cerebellar WM → Deep cerebellar nuclei

Cerebellar Deep Nuclei (Medial to Lateral)

Fastigial Nucleus → interposed nucleus → dentate nucleus (largest)

Vermis

coordinate trunk movements

Intermediate/Paravermis

coordinate distal extremities

Lateral hemisphere function

planning of sequential movement of body, conscious assessment of movement errors

White Matter Tract Categories

projection, association, and commissural

Limbic WM Tracts

cingulum, fornix, and stria terminalis

Projection WM tracts

afferent/efferent connections through deep nuclei, brainstem, cerebellum, and spinal cord

Cerebral Peduncles

all WM tracts run through here before going to the spinal cord

Caudal Medulla

75-90% of fibers cross contralaterally for control

Corticospinal Tracts

begin in cortex, terminate in spinal grey matter, controls motor control

Association Tracts

move anterior-posterior to ipsilateral cortex

Short Association Tracts

connect adjacent gyri, u-shaped

Long Association Tracts

connect different ipsilateral lobes

Commissural Tracts

connect homologous cortical hemisphere structures

Cingulum

Connects all medial aspects of each lobe, for emotion and motivation

Limbic tracts

cingulum, fornix, stria terminalis

Fornix Connections

structurally connected to hippocampus and thalamus

Fornix shape

similar to uterus and fallopian tubes

Stria Terminalis

specific to limbic system, from amygdala to hypothalamus

Corona Radiata

joining of cortico- tracts

Internal Capsule

Joining of ascending and descending fibers between GPi and thalamus

Circle of Willis

primary blood supply for the brain, fed by internal carotid and vertebral arteries that merges to become basilar artery