ISSN:
1432-1106
Keywords:
Visual cortex
;
Receptive fields
;
Response specificity
;
Electrophoresis
;
Glutamate
;
GABA
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Changes of specific response properties of single neurones in area 17 of the cat's cortex were studied during electrophoretic administration of glutamate and gamma-aminobutyric acid (GABA). Most cells were excited by glutamate. The diameter of the cells' discharge field (ERF) was enlarged by less than 1° in most cells, and the amplitude of the response within the ERF was increased. There was a weak correlation between the original size of the ERF and its enlargement during glutamate. Stimuli presented in non-optimal orientations and moved in the non-optimal direction became also effective in eliciting an excitatory response. When glutamate “doses” sufficiently high to increase background activity were used, inhibitory regions of the receptive fields could be revealed. GABA decreased the excitability of the cells until the response was totally blocked. In some cases, glutamate also decreased the excitability of cells. Simultaneous recordings from two cells suggested that the inhibitory effect may be indirect through activation of nearby inhibitory neurones. It is pointed out that extracellular recording combined with electrophoretic administration of glutamate can reveal information about a cell's properties which can otherwise only be obtained with intracellular recordings. The functional implications of the results are discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00235748
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