The Effect of Spatial Attention on Contrast Response Functions in Human Visual Cortex: Figure 1.

Buračas, Giedrius T.; Boynton, Geoffrey M.

doi:10.1523/jneurosci.3162-06.2007

Cited by 189 publications

(223 citation statements)

References 27 publications

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“…This is supported by the recent finding that spatial attention adds a constant BOLD signal independent of stimulus strength in V1 (Buracas and Boynton, 2007). Because stimulus onsets attract attention, such a hemodynamic effect might explain the temporal nonlinearities observed in most fMRI studies, in which responses to brief auditory and visual stimuli are much larger than expected from the responses to stimuli of longer durations (Birn et al, 2001).…”

Section: Discussionmentioning

confidence: 68%

Spatial Attention Does Not Strongly Modulate Neuronal Responses in Early Human Visual Cortex

Yoshor

Ghose²,

Bosking

et al. 2007

J. Neurosci.

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Attention can dramatically enhance behavioral performance based on a visual stimulus, but the degree to which attention modulates activity in early visual cortex is unclear. Whereas single-unit studies of spatial attention in monkeys have repeatedly revealed relatively modest attentional modulations in V1, human functional magnetic resonance imaging studies demonstrate a large attentional enhancement of the blood oxygen level-dependent (BOLD) signal in V1. To explore this discrepancy, we used intracranial electrodes to directly measure the effect of spatial attention on the responses of neurons near the human occipital pole. We found that spatial attention does not robustly modulate stimulus-driven local field potentials in early human visual cortex, but instead produces modest modulations that are consistent with those seen in monkey neurophysiology experiments. This finding suggests that the neuronal activity that underlies visual attention in humans is similar to that found in other primates and that behavioral state may alter the linear relationship between neuronal activity and BOLD.

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Section: Discussionmentioning

confidence: 68%

Spatial Attention Does Not Strongly Modulate Neuronal Responses in Early Human Visual Cortex

Yoshor

Ghose²,

Bosking

et al. 2007

J. Neurosci.

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“…Two studies have reported results supporting both (Huang and Dobkins 2005;Ling and Carrasco 2006). Functional imaging studies found evidence supporting an additive effect of attention (Buracas and Boynton 2007) (Ekstrom et al 2009). These results are important in their own right, but they provide little guidance for anticipating the effects of attention on the firing rates of individual neurons.…”

Section: Psychophysics and Imagingmentioning

confidence: 99%

The Effect of Attention on Neuronal Responses to High and Low Contrast Stimuli

Lee

Maunsell

2010

Journal of Neurophysiology

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Lee J, Maunsell JHR. The effect of attention on neuronal responses to high and low contrast stimuli. J Neurophysiol 104: 960 -971, 2010. First published June 10, 2010 doi:10.1152/jn.01019.2009. It remains unclear how attention affects the tuning of individual neurons in visual cerebral cortex. Some observations suggest that attention preferentially enhances responses to low contrast stimuli, whereas others suggest that attention proportionally affects responses to all stimuli. Resolving how attention affects responses to different stimuli is essential for understanding the mechanism by which it acts. To explore the effects of attention on stimuli of different contrasts, we recorded from individual neurons in the middle temporal visual area (MT) of rhesus monkeys while shifting their attention between preferred and nonpreferred stimuli within their receptive fields. This configuration results in robust attentional modulation that makes it possible to readily distinguish whether attention acts preferentially on low contrast stimuli. We found no evidence for greater enhancement of low contrast stimuli. Instead, the strong attentional modulations were well explained by a model in which attention proportionally enhances responses to stimuli of all contrasts. These data, together with observations on the effects of attention on responses to other stimulus dimensions, suggest that the primary effect of attention in visual cortex may be to simply increase the strength of responses to all stimuli by the same proportion.

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“…In humans, some fMRI studies have described contrastindependent attentional modulation of BOLD signals in visual cortex (Buracas and Boynton, 2007;Murray, 2008), while others have reported contrast-dependent modulations (Li et al, 2008; see also Ekstrom et al, 2009 in the monkey). Behavioral studies have also described both modulation types of psychometric functions (Carrasco, 2006).…”

Section: Introductionmentioning

confidence: 99%

Attention Differentially Modulates Similar Neuronal Responses Evoked by Varying Contrast and Direction Stimuli in Area MT

Khayat¹,

Niebergall²,

Martinez‐Trujillo³

2010

J. Neurosci.

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The effects of attention on the responses of visual neurons have been described as a scaling or additive modulation independent of stimulus features and contrast, or as a contrast-dependent modulation. We explored these alternatives by recording neuronal responses in macaque area MT to moving stimuli that evoked similar firing rates but varied in contrast and direction. We presented two identical pairs of stimuli, one inside the neurons' receptive field and the other outside, in the opposite hemifield. One stimulus of each pair always had high contrast and moved in the recorded cell's antipreferred direction (AP pattern), while the other (test pattern) could either move in the cell's preferred direction and vary in contrast, or have the same contrast as the AP pattern and vary in direction. For different stimulus pairs evoking similar responses, switching attention between the two AP patterns, or directing attention from a fixation spot to the AP pattern inside or outside the receptive field, produced a stronger suppression of responses to varying contrast pairs, reaching a maximum (ϳ20%) at intermediate contrast. For invariable contrast pairs, switching attention from the fixation spot to the AP pattern produced a modulation that ranged from 10% suppression when the test pattern moved in the cells preferred direction to 14% enhancement when it moved in a direction 90°away from that direction. Our results are incompatible with a scaling or additive modulation of MT neurons' response by attention, but support models where spatial and feature-based attention modulate input signals into the area normalization circuit.

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The Effect of Spatial Attention on Contrast Response Functions in Human Visual Cortex: Figure 1.

Cited by 189 publications

References 27 publications

Spatial Attention Does Not Strongly Modulate Neuronal Responses in Early Human Visual Cortex

Spatial Attention Does Not Strongly Modulate Neuronal Responses in Early Human Visual Cortex

The Effect of Attention on Neuronal Responses to High and Low Contrast Stimuli

Attention Differentially Modulates Similar Neuronal Responses Evoked by Varying Contrast and Direction Stimuli in Area MT

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