Spinal sensorimotor transformation: Relation between cutaneous somatotopy and a reflex network

摘要: The projection of primary afferents onto spinal interneurons constitutes the first step in sensorimotor transformations performed by reflex systems. Despite extensive studies on somatotopy, uncertainties remain concerning extent and significance representational overlap relation to circuits. To address these issues, cutaneous from hindpaw its topography lamina V neurons encoding withdrawal strength ("reflex encoders") was studied rats. Thin coarse afferent terminations laminas II III-IV, respectively, were mapped wheat germ agglutinin-horseradish peroxidase choleragenoid tracing. functional weights projections characterized mapping nociceptive tactile field potentials compared with encoders. Both anatomical physiological data indicate that thin skin input is spatially congruent horizontal plane. representation cord found be intricate, a high degree convergence between different sites. "Somatotopic disruptions" such as central pads medial digits common. weight distribution patterns III-IV similar This suggests features somatotopic disruptions have specific relations deep dorsal horn. Hence, map may better understood light