Lecture 5/6 Flashcards
DCML
conveys proprioception, vibration, fine touch
Anterolateral pathways
has three tracts
spinothalamic
spinoreticular
spinomesencephalic
ALS conveys
pain, temperature, crude touch
ALS First order neuron
enter via dorsal root entry zone
ascend and descend via Lissauer’s tract
synapse in gray matter of dorsal horn
Second order neuron ALS
cross over in anterior commissure
run inbetween inferior olives and inferior cerebellar peduncles
enter tegmentum, and medial lemniscus
3rd order neuron ALS/spinothalamic
VPL = internal capsule, corona radiata, SI
VMP = projects to insular cortex, stimulus quality
MN = cingulate gyrys, emotional, learning, memory
3rd order neuron spinoreticular tract
reticular formation in medulla and pons
goes to amygdala
receives sensory info that regulates arousal
3rd order neuron spinomesencephalic tract
terminates in midbrain tectum and PAG
vision, hearing, orienting head
pain transmission to spinal cord
Somatosensory cortex….
projects to the secondary somatosensory association cortex
lesions = cortical sensory loss
Descending pathway of pain
controls or inhibits pain as needed
PAG neurons in midbrain go down and synapse with raphe nuclei in medulla. use serontonin
serotonin controls the 1st and 2nd order synpases going UP
interneuron is also used to inhibit the 1st and 2nd order neuron
Visceral pain
neurons in dorsal horn of all parts of sacral to thoracic receive input from organs
neurons for these pains stay ipislateral and follow DCML pathway
visceral info and cutaneous info can be confused in lamina V because the two receptors converge
Lateral corticospinal tract conveys
motor
Primary motor cortex is the same as….
brodmann’s area 4
precentral gyrus
M1
Primary sensory cortex is the same as….
brodmann’s area 1,2,3
postcentral gyrus
S1
Substantia gelatinosa
important in pain
Feedback loops
the cerebellum and basal ganglia form these
project back to the cortex via thalamus
Upper motor neurons
carry motor system outputs
arise from cerebral cortex and brainstem
descend
have both lateral and medial UMN
Lower motor neurons
located in spinal cord and brain stem
project to muscles
classified as alpha, gamma, beta
Alpha motor neurons
large vell bodies and axons innervating skeletal muscle
Gamma motor neurons
small axon fiber and innervate muscle spindles
Beta motor neurons
innervate muscle fibers
Lateral corticospinal tract
most CLINICALLY important descending
originate in primary motor cortex –> corona radiata –> post internal capsule –> SKIP THALAMUS –> midbrain cerebral peduncles –> basis pons –> cross in pyramids –>spinal cord
Rubrospinal tract
Red nucleus of midbrain –> cross in ventral tegmentum –> descends in pons and medulla –> ends in cervical spine in lateral column
Ventral corticospinal tract
cortical layer of cerebral cortex –> corona radiata –> post limb of internal capsule –> SKIP THALAMUS –> midbrain cerebral peduncles –> basis pons –> pyramids –> ends in upper thoracic
Lateral corticospinal purpose
movement of contralateral limbs
Rubrospinal tract purpose
movement of contralateral limbs
uncertain function in humans
Anterior corticospinal tract purpose
control of bilateral axial and girdle muscles
Medial VST purpose
positioning of head and neck
Lateral VST purpose
balance
Reticulospinal tract purpose
autonomic posture and gait-related movements
Tectospinal tract purpose
coordination of head and eye movements
uncertain in humans
Lateral VT
vestibular nucleus in pons –> lateral tegmentum in medulla –> entire spinal cord in Rexed 7
Medial VT
medial, inferior vestibular nuclei, medulla –> medial longitudinal fasciculus –> cervical spinal cord
Tectospinal tract
superior colliculus midbrain –> crosses in tegmentum midbrain –> central tegmentum medulla –> ventral column of SC, Rex 7 –> ends in cervical
Pontine reticulosponal tract
pontine reticular formation –> central tegmentum –> ventral spinal cord, Rex 7 & 8 –> ends in sacral spine
Medullary reticulosponal tract
medullary reticular formation –> central tegmentum –> ventral spinal cord Rex 7 &8 –> ends in sacrum
