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Structure and dynamics of receptive fields in the visual cortex of the cat (area 18) and the influence of GABAergic inhibition
Author(s) -
Pernberg Joachim,
Jirmann KayUwe,
Eysel Ulf T.
Publication year - 1998
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.1998.00364.x
Subject(s) - receptive field , neuroscience , inhibitory postsynaptic potential , simple cell , gabaergic , stimulus (psychology) , visual cortex , bicuculline , excitatory postsynaptic potential , gabaa receptor , chemistry , lateral inhibition , psychology , receptor , biochemistry , psychotherapist
Receptive fields (RFs) in the visual cortex are characterized by spatiotemporal profiles that have been described in detail for area 17 simple cells. In this study, we analyse spatial and temporal RF properties of simple and complex cells in layer II/III of area 18 of the anaesthetized adult cat, using the reverse correlation method with brief 50 ms presentations of flashing bright and dark bars. Stimuli were presented with preferred orientation as previously determined by moving bars. Simple cell RFs were characterized by spatially and temporally separable ON and OFF subfields, while in complex cells ON and OFF subfields were superimposed. To discriminate possible contributions of GABAergic inhibition to RF structure and response dynamics in area 18, we have used three‐barrelled micropipettes for single cell recordings and microiontophoresis, and have documented ON and OFF responses before, during and after application of bicuculline methiodide for blockade of GABA A receptors. During blockade of GABAergic inhibition, the stimulus‐induced and resting discharge frequency increased, and in about 50% of the cells both ON and OFF subfields changed significantly in space and/or time in a reversible manner. In space, blockade of inhibition widened RF subfields, whereas in time, it shortened the duration of the excitatory cell response in simple and complex cells. ON and OFF subfields separated in space and time (simple cells), or time (complex cells) became less isolated or even superimposed. The results indicate substantial local inhibitory processing contributing to spatiotemporal RF properties in layers II/III of area 18 of the cat.