Cue-induced temporal attention affects contrast response function by response gain

Abstract Orienting attention to a specific point in time has been shown to improve the contrast sensitivity at the attended time point and impair it earlier or later. This phenomenon could be explained by temporal attention increasing the effective contrast of target presented at the attended time point which leads to changes in contrast psychometric function by contrast gain. Another explanation is that temporal attention proportionally amplifies the amplitude of (behavioral or neural) response to contrast, resulting in alterations in contrast psychometric function by response gain. To explore the underlying mechanism, we adopted a temporal cueing orientation discrimination task using audio pre-cues composed of different frequency components to induce different attentional bias in time domain and targets of various contrast intensities to measure contrast psychometric functions. Obtained psychometric functions for contrast sensitivity were fitted for different conditions with discrepant attention states in time. We found that temporal attention manipulated by cue affected contrast psychometric function by response gain, indicating that multiplying contrast response of visual target occurring at the selected point in time by a fixed factor is a crucial way for temporal attention to modulate perceptual processing.