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Rosanne Rademaker, Sam Ling, Alexander Sack; Arousal state enhances contrast sensitivity under conditions of exogenous attention. Journal of Vision 2016;16(12):1135. doi: 10.1167/16.12.1135.
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© ARVO (1962-2015); The Authors (2016-present)
While physiological arousal is assumed to heighten the senses, little is actually known regarding how arousal states influence basic perceptual processing. Arousal states could prompt a wholesale modulation of the entire sensorial environment, or alternatively act primarily on behaviorally relevant information. Here we investigated if and how arousal might influence basic visual processing by assessing contrast sensitivity under physiological stress, induced by exposure to ice water (Cold Pressor Test). Specifically, we aimed to distinguish between mechanisms of attention and arousal: Does arousal mimic the effects of visual attention on contrast sensitivity, or do attention and arousal interact? We estimated contrast psychometric functions for thirty participants, who discriminated the orientation of peripherally presented gratings at 8 different levels of contrast. Exogenous attention was manipulated using a transient cue that briefly appeared either at fixation (neutral cue) or adjacent to an upcoming grating location (attended condition). Following the offset of the exogenous cue, participants performed a 2AFC fine orientation discrimination task on a grating that could appear in one of four locations (4° eccentricity). Critically, participants performed the tasks under two conditions: Once while their foot was submerged in comfortably warm water (~36° C), and a second time when the water was near freezing (~3° C). Consistent with prior work, psychometric functions revealed shifts towards higher sensitivity under the attended condition. However, contrast sensitivity was unaffected by water temperature in the unattended condition, demonstrating that arousal itself did not boost visual sensitivity. Interestingly, in the attended condition cold water increased visual sensitivity beyond the already observed increase with warm water, indicating that arousal can amplify the effects of attention, further increasing visual sensitivity. Taken together, these results suggest that arousal acts to prioritize the processing of behaviorally relevant visual information by innervating and acting on the exogenous attentional system.
Meeting abstract presented at VSS 2016
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