Abstract
It has been long known that prolonging stimulus duration may increase the perceived brightness of a stimulus by our visual system. The trade-off interaction between intensity and duration generally follows a rule, such as described in Bloch’s law. Similarly, auditory temporal integration has been investigated using the cat as an animal model. The goal of this study is to develop a visual task whereby the cat can be used as a suitable model for studying both auditory and visual temporal integration. We successfully trained five cats to remain stationary during fixation and make a response by rapidly approaching a reward dispenser when a brief luminance change was detected in the fixation dot. Following training, we measured the success rate of detecting the luminance change with varying durations (17-ms, 50-ms, 83-ms, 117-ms, 150-ms, 183-ms) at threshold, subthreshold, and suprathreshold luminance levels. Psychometric functions averaged across 13 testing sessions showed that the effect of prolonging stimulus duration on improving the task performance was statistically significant (F5,72=2.61, p=0.032<.05) and was most noticeable for stimuli shorter than 83-ms. Psychometric functions derived from 9 out of 13 individual sessions were better fit to an exponential model than to a linear model. The gradually saturated performance observed here, as in previous studies, can be explained by the “leaky integrator” hypothesis, where temporal integration is considered valid only when sensory input falls within a time window whose length defines a critical duration. The performance saturation is unlikely to be a ceiling effect caused by task proficiency, as the success rate for the longest stimuli were still modulated by luminance level. Based on the outcome of this study, future research can consider using the cat as an animal model to investigate the factors on temporal integration, such as modal-specificity, inhibition, subject bias, and their underlying neural circuits.