Publications

Authors:

Sani, Ilaria; Santandrea, Elisa; Morrone, Maria Concetta; Chelazzi, Leonardo

Title:

Temporally evolving gain mechanisms of attention in macaque area V4

Year:

2017

Type of item:

Articolo in Rivista

Tipologia ANVUR:

Articolo su rivista

Language:

Inglese

Format:

A Stampa

Referee:

Sì

Name of journal:

Journal of Neurophysiology

ISSN of journal:

0022-3077

N° Volume:

118

Number or Folder:

2

Page numbers:

964-985

Keyword:

contrast response functions; gain mechanisms of attention; macaque area V4; spatial attention; temporal dynamics

Short description of contents:

Cognitive attention and perceptual saliency jointly govern our interaction with the environment. Yet, we still lack a universally accepted account of the interplay between attention and luminance contrast, a fundamental dimension of saliency. We measured the attentional modulation of V4 neurons' contrast response functions (CRFs) in awake, behaving macaque monkeys and applied a new approach that emphasizes the temporal dynamics of cell responses. We found that attention modulates CRFs via different gain mechanisms during subsequent epochs of visually driven activity: an early contrast-gain, strongly dependent on prestimulus activity changes (baseline shift); a time-limited stimulus-dependent multiplicative modulation, reaching its maximal expression around 150 ms after stimulus onset; and a late resurgence of contrast-gain modulation. Attention produced comparable time-dependent attentional gain changes on cells heterogeneously coding contrast, supporting the notion that the same circuits mediate attention mechanisms in V4 regardless of the form of contrast selectivity expressed by the given neuron. Surprisingly, attention was also sometimes capable of inducing radical transformations in the shape of CRFs. These findings offer important insights into the mechanisms that underlie contrast coding and attention in primate visual cortex and a new perspective on their interplay, one in which time becomes a fundamental factor. NEW & NOTEWORTHY We offer an innovative perspective on the interplay between attention and luminance contrast in macaque area V4, one in which time becomes a fundamental factor. We place emphasis on the temporal dynamics of attentional effects, pioneering the notion that attention modulates contrast response functions of V4 neurons via the sequential engagement of distinct gain mechanisms. These findings advance understanding of attentional influences on visual processing and help reconcile divergent results in the literature.

Web page:

https://doi.org/10.1152/jn.00522.2016

Product ID:

98628

Handle IRIS:

11562/967421

Last Modified:

November 15, 2022

Bibliographic citation:

Sani, Ilaria; Santandrea, Elisa; Morrone, Maria Concetta; Chelazzi, Leonardo, Temporally evolving gain mechanisms of attention in macaque area V4 «Journal of Neurophysiology» , vol. 118 , n. 2 , 2017 , pp. 964-985

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