SBI Research Seminar October 27, 12.15-13.15

“Processing of geometric features in human first-order tactile neurons.”


Roland S Johansson, prof

Department of Integrative Medical Biology
Umeå university

Place: Tellus, Karolinska Institutet, Scheeles väg 1, plan 5

ABSTRACT: A fundamental feature of first-order neurons in the tactile system is that their distal axon branches in the skin and forms many transduction sites, yielding complex receptive fields with many highly sensitive zones. The functional consequences of this arrangement are unknown. We have recently found that it constitutes a peripheral neural mechanism that allows individual neurons to signal geometric features of touched objects. Specifically, two types of tactile afferent neurons that densely innervate the glabrous skin of the human fingertips signal edge orientation via both the intensity and the temporal structure of their responses. Moreover, a neuron’s sensitivity to edge orientation can be readily predicted from the spatial layout of its highly sensitive zones. Like peripheral neurons in the visual-processing pathway, peripheral neurons in the tactile-processing pathway perform feature extraction computations traditionally attributed to neurons in the cerebral cortex.




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