Optical imaging of intrinsic signals in somatosensory cortex

    Authors

    M. Tommerdahl; O. Favorov;B. L. Whitsel

    Comments

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    Abbreviated Journal Title

    Behav. Brain Res.

    Keywords

    optical imaging; somatosensory cortex; receptive fields; lateral; inhibition; cortical dynamics; ANTERIOR PARIETAL CORTEX; AREA-1 CELL COLUMNS; RAT BARREL CORTEX; SPATIAL-ORGANIZATION; METABOLIC-ACTIVITY; CUTANEOUS FLUTTER; PERIPHERAL; INPUT; BODY-SURFACE; MONKEY SI; REPRESENTATION; Behavioral Sciences; Neurosciences

    Abstract

    The methods of optical intrinsic signal (OIS) imaging and microelectrode mapping of single neuron receptive fields (RFs) were used in combination (in the same squirrel monkey or cat) to characterize the spatial and temporal attributes of the response of contralateral SI cortex to cutaneous flutter stimulation. A change in the location of the stimulated skin site was accompanied by a shift in the locus of the SI optical response. The spatial ordering of the optical responses to independent stimulation of each site in an array of skin sites was consistent with the features of SI topographical organization described in published RF mapping studies. While the single neuron RF mapping observations and the optical response obtained at a given time after onset of flutter stimulation always were positively correlated, the degree of correlation improved progressively with time after stimulus onset (the longest stimulus duration used was 10 s). Analysis of the temporal development of the optical response to cutaneous flutter stimulation revealed that not only does absorbance increase to attain a maximum in the SI region which receives its main input from the stimulated skin site, but at the same time absorbance declines to below-background values in an extensive region of surrounding cortex. The results are interpreted to indicate that the pattern of SI activity evoked by a cutaneous flutter stimulus exhibits increasing spatial contrast (becomes progressively more distinguishable from the activity of surrounding cortex) over periods of continuous stimulation at least as long as 10 s. This time-dependent 'funneling' of the SI spatial activity pattern is proposed to underlie the prominent enhancement of human spatial discriminative capacity which occurs (e.g. Physiol. Behav. 5 (1970) 1431) when oscillatory tactile stimuli are used. (C) 2002 Elsevier Science B.V. All rights reserved.

    Journal Title

    Behavioural Brain Research

    Volume

    135

    Issue/Number

    1-2

    Publication Date

    1-1-2002

    Document Type

    Article; Proceedings Paper

    Language

    English

    First Page

    83

    Last Page

    91

    WOS Identifier

    WOS:000178541700014

    ISSN

    0166-4328

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