Pathways Flashcards
LATERAL CORTICAL SPINAL TRACT (LCST) is involved in which type of function? What is the name of the fibers and level of decussation?
LCST = MOTOR
Pyramidal decussation at the CERVICOMEDULLARY JUNCTION
DORSAL COLUMN MEDIAL LEMNISCAL PATHWAY (DCMLS) pathway is involved in which type of function? What is the name of the fibers and level of decussation?
DCMLS = SENSORY (Fine/discriminative touch, proprioception, vibration sense)
Internal arcuate fibers - Decussate at LOWER/CAUDAL MEDULLA
ANTERIOR SPINOTHALAMIC TRACT (STT) is involved in which type of function? What is the name of the fibers and level of decussation?
STT = SENSORY (Crude touch, pain, temperature)
Anterior commissure fibers - Decussate at level of SPINAL CORD
What is pathway of DCMLS?
1) DORSAL ROOT GANGLION cell body -> synapses onto dorsal columns gracilis or cuneatus (spinal cord) -> Travels up spinal cord -> synapses onto
2) NUCLEUS CUNEATUS/GRACILIS (caudal medulla) Decussates here -> Travels up medulla, pons, midbrain -> Synapses onto
3) Ventral posterior lateral nucleus of the thalamus -> Sends info to PRIMARY SOMATOSENSORY CORTEX
What is the pathway of LCST?
1) CEREBRAL CORTEX SENSORY NEURONS (predominantly in Cortical Layer V) -> Sends axons to corona radiata -> Descends in posterior limb of internal capsule -> Descneds into MIDBRAIN CEREBRAL PEDUNCLES -> pons -> Medulla -> 85% Decussate at cervicomedullary junction -> Enter lateral white matter columns of spinal cord -> Synapse onto
2) Lateral motor nuclei (LMN) DIRECTLY OR INTERNEURONS OF LATERAL VENTRAL HORN -> DISTAL MUSCLES
What is the pathway of STT?
1) Primary sensory neuron in DORSAL ROOT GANGLION -> Synapses onto
2) GRAY MATTER OF SPINAL CORD in DORSAL HORN -> Takes 2-3 spinal segments for DECUSSATING fibers at the anterior commissure (**Lateral cord lesion affects contralateral pain, temperature 2 segments below lesion) -> Medulla -> Pons -> Midbrain -> Synapses onto
3) VENTRAL POSTERIOR LATERAL NUCLEUS OF THALAMUS -> Projects to PRIMARY SOMATOSENSORY CORTEX
