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Titolo:
Tactile discrimination of edge shape: Limits on spatial resolution imposedby parameters of the peripheral neural population
Autore:
Wheat, HE; Goodwin, AW;
Indirizzi:
Univ Melbourne, Dept Anat & Cell Biol, Melbourne, Vic 3010, Australia UnivMelbourne Melbourne Vic Australia 3010 elbourne, Vic 3010, Australia
Titolo Testata:
JOURNAL OF NEUROSCIENCE
fascicolo: 19, volume: 21, anno: 2001,
pagine: 7751 - 7763
SICI:
0270-6474(20011001)21:19<7751:TDOESL>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
RAPIDLY ADAPTING MECHANORECEPTORS; GLABROUS SKIN; CUTANEOUS MECHANORECEPTORS; RESPONSE VARIABILITY; CORTICAL-NEURONS; MONKEY FINGERPAD; HUMAN HAND; STIMULUS LOCATION; PRIMARY AFFERENTS; NERVE-FIBERS;
Keywords:
tactile resolution; mechanoreceptive afferents; somatosensory; form processing; spatial coding; innervation density; curvature; edges;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
63
Recensione:
Indirizzi per estratti:
Indirizzo: Wheat, HE Univ Melbourne, Dept Anat & Cell Biol, Melbourne, Vic 3010, Australia Univ Melbourne Melbourne Vic Australia 3010 Vic 3010, Australia
Citazione:
H.E. Wheat e A.W. Goodwin, "Tactile discrimination of edge shape: Limits on spatial resolution imposedby parameters of the peripheral neural population", J NEUROSC, 21(19), 2001, pp. 7751-7763

Abstract

When the flat faces of a coin are grasped between thumb and index finger, a "curved edge" is felt. Analogous curved edges were generated by our stimuli, which comprised the flat face of segments of annuli applied passively to immobilized fingers. Humans could scale the curvature of the annulus and could discriminate changes in curvature of similar to 20 m(-1). The responses of single slowly adapting type I afferents (SAIs) recorded in anesthetized monkeys could be quantified by the product of two factors: their sensitivity and a spatial profile dependent only on the radius of the annulus. This allowed us to reconstruct realistic SAI population responses that included noise, variation in fiber sensitivity, and varying innervation patterns. The critical question was how relatively small populations (similar to 70 active fibers) can encode edge curvature with such precision. A template-matching approach was used to establish the accuracy of edge representation inthe population. The known large interfiber variability in sensitivity had no effect on curvature resolution. Neural resolution was superior to human performance until large levels of central noise were present showing that, unlike simple detection, spatial processing is limited centrally. In contrast to the behavior of mean response codes, neural resolution improved with increasing covariance in noise. Surprisingly, resolution for any single population varied considerably with small changes in the position of the stimulus relative to the SAI matrix. Overall innervation density was not as critical as the spacing of receptive fields at right angles to the edge.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/10/20 alle ore 15:35:14