Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences
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Adaptation to contingencies in macaque primary visual cortex

Matteo Carandini

Matteo Carandini

Howard Hughes Medical Institute and Center for Neural Science, New York UniversityNew York, NY 10003USA

[email protected]

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,
Horace B. Barlow

Horace B. Barlow

The Physiological Laboratory, University of CambridgeCambridge CB2 3EGUK

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,
Lawrence P. O'keefe

Lawrence P. O'keefe

Howard Hughes Medical Institute and Center for Neural Science, New York UniversityNew York, NY 10003USA

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Allen B. Poirson

Allen B. Poirson

Howard Hughes Medical Institute and Center for Neural Science, New York UniversityNew York, NY 10003USA

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J. Anthony Movshon

J. Anthony Movshon

Howard Hughes Medical Institute and Center for Neural Science, New York UniversityNew York, NY 10003USA

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    We tested the hypothesis that neurons in the primary visual cortex adapt selectively to contingencies in the attributes of visual stimuli. We recorded from single neurons in macaque V1 and measured the effects of adaptation either to the sum of two gratings (compound stimulus) or to the individual gratings. According to our hypothesis, there would be a component of adaptation that is specific to the compound stimulus. In a first series of experiments, the two gratings differed in orientation. One grating had optimal orientation and the other was orthogonal to it, and therefore did not activate the neuron under study. These experiments provided evidence in favour of our hypothesis. In most cells adaptation to the compound stimulus reduced responses to the compound stimulus more than it reduced responses to the optimal grating, and adaptation to the optimal grating reduced responses to the optimal grating more than it reduced responses to the compound stimulus. This suggests that a component of adaptation was specific to (and caused by) the simultaneous presence of the two orientations in the compound stimulus. To test whether V1 neurons could adapt to other contingencies in the stimulus attributes, we performed a second series of experiments, in which the component gratings were parallel but differed in spatial frequency, and were both effective in activating the neuron under study. These experiments failed to reveal convincing contingent effects of adaptation, suggesting that neurons cannot adapt equally well to all types of contingency.