Midbrain

Question 1

Division of midbrain

Answer 1

Dorsal: Tectum (4 colliculi)
Ventral: Crus cerebri
Central: tegmentum (continuous with pons)

Question 2

Substantia nigra location

Answer 2

separates tegmentum from crus cerebri

Question 3

Periaqueductal gray (PAG) location

Answer 3

separates tegmentum from tectum, surrounds cerebral aqueduct (connects 3rd and 4th ventricles)

Question 4

Inferior colliculus

Answer 4

receives auditory inputs (supplied via lateral lemniscus pathway) in turn projects on to brachium of inferior colliculus to medial geniculate nucleus

Question 5

Raphe nuclei

Answer 5

contains serotonin-producing neurons

Question 6

Crus cerebri

Answer 6

contain massive bundles of descending axons from the cerebral cortex (corticospinal fibers)

Question 7

Two groups of substantia nigra cells

Answer 7

1) pars compacta (medial) - produces dopamine and releases onto neostriatum (caudate and putamen) REMEMBER CD - compacta dopamine
2) pars reticulata (lateral) - projects to thalamus and uses GABA as a neurotransmitter

Question 8

Superior colliculus

Answer 8

retinal inputs and projects onto cervical spinal cord to produce reflex movements of head and neck in response to sensory inputs (regulates oculomotor responses)

Question 9

red nucleus

Answer 9

present in rostral midbrain (replaces superior cerebellar peduncle) plays an important role in motor functions
projects axons on to ION which supplies contralateral cerebellar cortex