Brainstem and function

Question 1

Name the input, output and function of the inferior colliculus

Answer 1

Input: cochlea, bs nuclea
Output: Auditory cortex, med geniculate body of thalamus
Function: Relays auditory info, sound localisation

Question 2

Name the input, output and function of the superior colliculus

Answer 2

Input: retina, visual cortex
Output: bs, tectospinal tract
Function: Eye orientation, track movements, gaze shifting

Question 3

Name the input, output and function of the mamillary bodies

Answer 3

Input: hippocampus, fornix, cingulate, amygdala, hypothalamus
Output: Cingulate, ant body of thalamus
Function: Episodic, implicit and spatial memory

Question 4

What is the function of the olives?

Answer 4

Movement via components of the extra pyramidal system

Question 5

Describe the corticobulbar tract

Answer 5

Subset of UMNs originating in layer 5 of the primary motor cortex in the somatotopic region corresponding to head and face.
Tract fibres synapse with some cranial nerve nuclei that produce head, neck and face movement (LMNs)

Question 6

Describe the tectospinal tract

Answer 6

Originates in superior colliculus

Descend quick and decussates medially, synapse with upper cervical levels of sc

Question 7

Describe the Rubrospinal tract

Answer 7

Originates in red nucleus
Decussates quickly and descends laterally with corticospinal tract, synpapse in cervical levels

Flex distal muscles
Receives info from spinocerebellum and cerebrocerebellum

Question 8

Vestibulospinal tract

Answer 8

Originates in pontine vestibular nuclei.
Medial- synapses in the cervical levels of the spinal cord.
Lateral- synapses in many levels of the spinal cord.

Assists with maintaining head position (medial) and balance and posture by stimulating muscles in the body (lateral).

The vestibular nuclei receives cerebellar input (vestibulocerebellum) via the inferior cerebellar peduncles.

Question 9

Reticulospinal tract

Answer 9

Originates in the pontine and medullary reticular formation.
Medial (pontine)- synapses throughout the spinal cord.
Lateral (medullary)- synapses throughout the spinal cord.

Assists in controlling trunk and upper and lower limb muscles (walking and posture).

The reticular formation receives cerebellar input (spinocerebellum) via the inferior cerebellar peduncles.

Question 10

Describe reticular formation

Answer 10

is an ill defined group of inter-mingled neurons that span the brain stem and involve a variety of neurotransmitters: serotonin, acetylcholine, catecholamines, orexin, glutamate, GABA, histamine.