Internal Anatomy of the Brainstem 2 Flashcards
What is the function of the inferior cerebellar peduncle?
Input pathway to the cerebellum for most ascending somatosensory infromation and from the inferior olive
What is the middle cerebellar peduncle?
Pathways for input to the cerebellum from the pontine nuclei in the basal pons
What is the superior cerebellar peduncle?
Major output pathway from the cerebellum to the midbrain and thalamus
What is the dorsal spinocerebellar tract?
Conveys unconscious proprioception from the lower limbes and trunk
Primary axons ascend in the gracile fasiculus and synapse in Clark’s nucleus
What is the cuneocerebellar tract?
Conveys uncsonscious proprioception from the upper limbs and trunk
Entirely ipsilateral, synapses in accessory cuneate nucleus
What is the ventral spinocerebellar tract?
Originates in interneurons in the intermediate zone of spinal cord grey matter
Decussates twice
Conveys information about movements of the lower limb and trunk, and adjustments in posture
What is the olivocerebellar pathway?
Inferior olivary nucleus neurons project to cerebellum through the inferior cerebellar peduncles
Important functions in motor learning
What is the vestibulocerebellar pathway?
Includes both primary vestibular afferents and the axons of secondary vestibular neurons
Provides vestibular information to the cerebellum through a portion of the inferior cerebellar peduncles called the juxtarestiform body
What is the corticopontocerebellar pathway?
Fibers from the cortex synapse in the ipsilateral pontine nuclei
Pontocerebellar fibers cross and enter the contralateral middle cerebellar peduncle
Pathway provides cerevellum with information about all the various sensations affecting the body and planned and ongoing movement
Where does output from the cerebellum go?
Through the superior cerebellar peduncles
Exception is some vestibular output
Decussate at the level of the inferior colliculi and project to the contralateral red nucleus and ventrolateral nucleus of the thalamus
What four symptoms result from lesions of the cerebellar peduncles?
Ataxia
Dysmetria
Vertigo
Nausea
Similar to cerebellar lesions
Where do afferents from taste-sensing CNs (VII, IX, X) project?
Rostral portion of the solitary nucleus
What is the pathway that mediates conscious taste sensation?
Ascending pathway from the solitary nucleus to the ventral posterior medial nucleus of the thalamus, and from there to the primary gustatory cortex
Where is the primary taste cortex?
Insula and frontal operculum of the cerebral hemispheres
What are saccades?
Very rapid, voluntary eye movements that serve to direct vision to objects of interest
