Abstract
Traditionally time perception has been considered the product of a central, generic, cognitive mechanism. However, evidence is emerging for a distributive system with modality-specific sensory components (Morrone et al., 2005; Johnston et al., 2006). Here we show that fast contrast adaptation, which can be observed in the retina, induces a change in apparent duration. The perceived duration of a subsecond interval containing a 50% luminance contrast drifting pattern is compressed when it follows a high (90%) as compared to a low (10%) contrast interval. The duration effect cannot be attributed to changes in latency at onset relative to offset, can be dissociated from the effect of contrast context on apparent speed or apparent contrast per se and it occurs in a retinocentric frame of reference. The temporal compression is limited to high drift temporal frequencies (≥10 Hz) and is not observed for equiluminant chromatic stimuli. This pattern of results indicates a major role for the magnocellular pathway in the neural encoding and representation of visual time.
Highlights
An increasing number of studies, targeting the subsecond range (Morrone et al, 2005; Johnston et al, 2006; Kanai et al, 2006; Burr et al, 2007; Terao et al, 2008) have shown that purely visual manipulations can alter the apparent duration of a stimulus
Our results show that the luminance contrast context of a visual stimulus has an effect on its perceived duration
If the fast adaptation effect depends upon magnocellular adaptation we should expect the temporal compression to disappear if we use a static contrast context
Summary
An increasing number of studies, targeting the subsecond range (Morrone et al, 2005; Johnston et al, 2006; Kanai et al, 2006; Burr et al, 2007; Terao et al, 2008) have shown that purely visual manipulations can alter the apparent duration of a stimulus. Benardete and Kaplan (1999) report that there is a very fast adaptation phase referred to as “contrast gain control” (Shapley and Victor, 1978; Mante et al, 2008) in primate ganglion cells, which consists of a decrease of contrast gain at low temporal frequencies delivering a more bandpass temporal frequency response (Figure 2 of Benardete and Kaplan, 1999). This occurs in M cells but not in P cells. This means that with increased contrast, the temporal impulse response function of an M cell shortens and advances (i.e., the peak of the function occurs progressively earlier when contrast is increased, Figure 5 of Benardete and Kaplan, 1999)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
