Interval timing in a hierarchical violation-of-expectation task: Dissociable effects of local and global predictions

The role of perceptual processing in the oddball effect revealed by the Thatcher illusion

When a novel stimulus (oddball) appears after repeated presentation of an identical stimulus, the oddball is perceived to last longer than the repeated stimuli, a phenomenon known as the oddball effect. We investigated whether the perceptual or physical differences between the repeated and oddball stimuli are more important for the oddball effect. To manipulate the perceptual difference while keeping their physical visual features constant, we used the Thatcher illusion, in which an inversion of a face hinders recognition of distortion in its facial features. We found that the Thatcherized face presented after repeated presentation of an intact face induced a stronger oddball effect when the faces were upright than when they were inverted (Experiment 1). However, the difference in the oddball effect between face orientations was not observed when the intact face was presented as the oddball after repeated presentation of a Thatcherized face (Experiment 2). These results were replicated when participants performed both the intact-repeated and Thatcherized-repeated conditions in a single experiment (Experiment 3). Two control experiments confirmed that the repeated presentation of the preceding stimuli is necessary for the difference in duration distortion to occur (Experiments 4 and 5). The results suggest the considerable role of perceptual processing in the oddball effect. We discuss the discrepancy in the results between the intact-repeated and Thatcherized-repeated conditions in terms of predictive coding.

Overlearned sequence and perceived time: possible involvement of attention

Overlearned sequences, characterized by specific ordinal ranks for each element, elicit strong predictions when presented in their natural order. The present study aimed to test the role of predictions on the perceived duration in a stimulus series that followed an overlearned sequence. Participants judged the duration of the target digit in a sequence that followed a regular or random order, while the overall context in which these sequences were presented was varied in two blocks. The results suggest that, with the possible involvement of attention, the target element that followed the regular order was perceived to be relatively accurate. The violation of an overlearned sequence leads to an underestimation of duration, particularly when the participants are aware of the violation. Further, the perceived duration of the target element in an overlearned sequence does not modulate as a function of the global context. These findings contribute to our understanding of the differential effect of various predictive processes on perceived time.

Core clock gene, Bmal1, is required for optimal second-level interval production

Perception and production of second-level temporal intervals are critical in several behavioral and cognitive processes, including adaptive anticipation, motor control, and social communication. These processes are impaired in several neurological and psychological disorders, such as Parkinson's disease and attention-deficit hyperactivity disorder. Although evidence indicates that second-level interval timing exhibit circadian patterns, it remains unclear whether the core clock machinery controls the circadian pattern of interval timing. To investigate the role of core clock molecules in interval timing capacity, we devised a behavioral assay called the interval timing task to examine prospective motor interval timing ability. In this task, the mouse produces two separate nose pokes in a pretrained second-level interval to obtain a sucrose solution as a reward. We discovered that interval perception in wild-type mice displayed a circadian pattern, with the best performance observed during the late active phase. To investigate whether the core molecular clock is involved in the circadian control of interval timing, we employed Bmal1 knockout mice (BKO) in the interval timing task. The interval production of BKO did not display any difference between early and late active phase, without reaching the optimal interval production level observed in wild-type. In summary, we report that the core clock gene Bmal1 is required for the optimal performance of prospective motor timing typically observed during the late part of the active period.