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Wu Li, Minggui Chen, Yin Yan, Feng Wang, Li Zhaoping; Modulation of Neuronal Responses in the Primary Visual Cortex by Exogenous Attention. Journal of Vision 2012;12(9):675. doi: 10.1167/12.9.675.
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© ARVO (1962-2015); The Authors (2016-present)
Visual perception is subject to the influences of selective attention achieved by voluntary deployment of cognitive resources or triggered by salient and unexpected stimuli. Modulation of visual cortical processing by voluntary or endogenous attention has been extensively studied over the past couple of decades, but little is known about the modulatory effects on responses of visual cortical neurons by involuntary or exogenous attention. In the current study we examined whether exogenous attention could affect responses of neurons recorded by multi-electrode array (Utah Array, Blackrock Microsystems) implanted in the primary visual cortex (V1) of awake monkeys. We used a conventional cueing paradigm whereby a sudden onset of a salient circle cue stimulus (60 ms) was followed by a probe grating stimulus (500 ms) with various luminance contrasts and stimulus onset asynchronies (SOAs). The probe was centered on the receptive fields (RFs) of the recorded neurons while the cue was placed either around the RFs or in the opposite visual field, or at both locations. The animal was doing a simple fixation task. Comparing different cueing conditions, we observed that, at low probe contrasts (5-15% ) and with an SOA of about 150 ms, the cue induced a remarkable transient increase of neuronal responses to the probe at the cued location, starting at about 60 ms and peaking around 100 ms after the onset of the neuronal responses to the probe, and lasting about 100 ms. This cueing effect is reminiscent of that documented in psychophysical studies. Moreover, the modulation of the neuronal responses by the cue diminished and disappeared after the animal became accustomed to the stimuli that were task-irrelevant; and the modulation tended to be retrieved by a novel new salient cue. Our observations indicate that exogenous attention triggered by unexpected and salient stimulus significantly modifies visual processing in V1.
Meeting abstract presented at VSS 2012
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