Internal Anatomy of Midbrain Flashcards

tectum

superior colliclus

brachium of inferior collilculus

crus cerebri

tegmentum of midbrain

cerebral aqueduct

Cerebral Peduncle (crus cerebri + grey matter of the tegementum)

prectal area
above the brachium


inferior colliculus
function: hearing, localization of sound
pathology: subtble deficits in localizing source of sound


Lateral lemniscus
function: hearing
pathology: no obvious sx from unilateral X


ALS /Spiunothalmic
function: carries propathic (simple touch, pressure, pain and temp from the OPPOSITE side of the body)
pathology: contralateral loss of propathic sensation beginning 2 segments below the lesion.


medial lemniscus
function: epicritic somatosensory for trunk and limbs on the OPPOSITE SIDE
pathology: loss of 2 point, vibration, position sense, asterognosis, shuffling gait

axons going through here

axons of the decussation of the superior cerebellar peduncle


Decussation of the superior cerebellar peduncle
function: carries signals of disparate function between cerebellum and brain stem
pathology: cerebellar signs: ataxia, intention tremor


corticospinal tract
function: motor control from cortex to motor neurons


medial longitudinal fascilus
function: coordinates head and eye position
pathology: contralateral eye cannot adduct for conjugate gaze, but can adduct during convergence


Nucleus of CN 4
function: rortates the eye and assists in abduction and downward movement
pathology: subtle effects in OPPOSITE EYE
slightl difficulty converging and looking downwards


Periaqueductal Gray
function: pain sensation, rich in endorphin receptors
pathology: in animals, blocks the benefit of analgesics

cerebral aqueduct


superior colliculus
functions: 1. sensory: vision, perhaps to focus visual attension on a sector of space
2. motor: controls roientaing movements of head and neck
pathology: subtle deficits..
1. partial neglect of contralateral visual space
2. slightly smaller saccades OPPOSITE the lesion


bracium of the inferior colliculus
function: conveys auditory signals to the midbrain to the thalamus
pathology: UNK (bilateral X is rare)
connections: inferior colliculus to the MGN
midbrain section, hole without the frog eyes


ALS/Spinothalamic tract
function: carries protopathic info
pathology: contralateral loss of protopathic sensation beginning two segments below the lesion


medial lemniscus
pathology: loss of 2 point, vibration, position sense, asterogenosis, shuffling gait


Decussation of superior cerebellar peduncle
pathology: cerebellar signs: ataxia, intentional tremor
































