Potential mismatches in structural and functional organization in the gracile nucleus
The gracile nucleus (GN) is a major brainstem processing center for somatosensory inputs. GN neurons often have functional receptive fields (RFs) on the toes, but there is little consensus on how these RFs are related to primary sensory inputs from toes. This project compared structural overlap in GN terminations of afferents from different toes, and numbers of toes in GN functional RFs. The results suggest that structural convergence of afferent terminations from at least 3-4 toes is common; in contrast, although some GN RFs reflected functional inputs from up to 4-5 toes, most RFs reflected inputs from 1-2 toes. These findings raise the possibility that structural convergence of sensory afferents from the toes is broader than the afferent convergence that is usually reflected in functional RFs. This type of potential mismatch has been previously described in somatosensory cortex and may partly explain rapid GN RF changes after disruptions of afferents.
School:University of Toledo Health Science Campus
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:gracile nucleus receptive fields dorsal column nuclei transganglionic transport primary afferents
Date of Publication:01/01/2008