Attentional modulation of adaptation in V4.

TitleAttentional modulation of adaptation in V4.
Publication TypeJournal Article
Year of Publication2009
AuthorsHudson, Andrew E., Schiff Nicholas D., Victor Jonathan D., and Purpura Keith P.
JournalEur J Neurosci
Date Published2009 Jul
KeywordsAction Potentials, Adaptation, Psychological, Analysis of Variance, Animals, Attention, Cues, Macaca mulatta, Male, Microelectrodes, Neurons, Neuropsychological Tests, Photic Stimulation, Reaction Time, Regression Analysis, Task Performance and Analysis, Time Factors, Visual Cortex, Visual Perception

Adaptation and visual attention are two processes that alter neural responses to luminance contrast. Rapid contrast adaptation changes response size and dynamics at all stages of visual processing, while visual attention has been shown to modulate both contrast gain and response gain in macaque extrastriate visual cortex. Because attention aims to enhance behaviorally relevant sensory responses while adaptation acts to attenuate neural activity, the question we asked is, how does attention alter adaptation? We present here single-unit recordings from V4 of two rhesus macaques performing a cued target detection task. The study was designed to characterize the effects of attention on the size and dynamics of a sequence of responses produced by a series of flashed oriented gratings parametric in luminance contrast. We found that the effect of attention on the response dynamics of V4 neurons is inconsistent with a mechanism that only alters the effective stimulus contrast, or only rescales the gain of the response. Instead, the action of attention modifies contrast gain early in the task, and modifies both response gain and contrast gain later in the task. We also show that responses to attended stimuli are more closely locked to the stimulus cycle than unattended responses, and that attended responses show less of the phase lag produced by adaptation than unattended responses. The phase advance generated by attention of the adapted responses suggests that the attentional gain control operates in some ways like a contrast gain control utilizing a neural measure of contrast to influence dynamics.

Alternate JournalEur. J. Neurosci.
PubMed ID19558603
PubMed Central IDPMC2770238
Grant ListEY07138 / EY / NEI NIH HHS / United States
EY09314 / EY / NEI NIH HHS / United States
F30 NS048703-03 / NS / NINDS NIH HHS / United States
GM07739 / GM / NIGMS NIH HHS / United States
NS048703 / NS / NINDS NIH HHS / United States

Weill Cornell Medicine Consortium for the Advanced Study of Brain Injury 520 East 70th Street New York, NY