The Anterolateral SystemPain and Temperature Transmision
The Anterolateral System is an ascending pathway conveying pain and temperature sensation.Cell bodies of the primary sensory neurons reside in the dorsal root ganglia and the trigeminal complex. This pathway receives input from thermoreceptors, nociceptors, and mechanoreceptors.
Getting into the Spinal CordPrimary axons synapse in Rexed layers I-IV of the dorsal hornSecondary axons cross in the anterior white column to form the anterolateral tract.
Sensation from the facePain and temperature sensation from the face are conveyed from fibers in the spinal trigeminal complex.These fibers cross in the brain stem and join the anterolateral tract.
Connections in the brain stemALT axons distribute to the reticular formation, central gray substance, and finally the intralaminar and posterior thalamusThe neospinothalamic tract distributes somatotopically in the ventral posterior thalamus: VPL - Leg, Trunk, ArmsVPM - Face
To the CortexFrom the VPL and theVPM of the thalamus,the fibers extend to the primary sensory cortex
Primary Sensory CortexSensory information from the ALS eventually terminates onthe postcentral gyrus of the brain.
The Homunculus!The arrangement of fibers correlates totheir entry into the spinal cord.Legs, feet,anklesShoulder,arms, abdomenHand(large thumb)FaceTongue