Partially Separable Aspects of Spatial and Temporal Estimations in Virtual Navigation as Revealed by Adaptation

Abstract

Recent studies claim that estimating the magnitude of the spatial and temporal aspects of one's self-motion shows similar characteristics, suggesting shared processing mechanisms between these two dimensions. While the estimation of other magnitude dimensions, such as size, number, and duration, exhibits negative aftereffects after prolonged exposure to the stimulus, it remains to be elucidated whether this could occur similarly in the estimation of the distance travelled and time elapsed during one's self-motion. We sought to fill this gap by examining the effects of adaptation on distance and time estimation using a virtual navigation task. We found that a negative aftereffect occurred in the distance reproduction task after repeated exposure to self-motion with a fixed travel distance. No such aftereffect occurred in the time reproduction task after repeated exposure to self-motion with a fixed elapsed time. Further, the aftereffect in distance reproduction occurred only when the distance of the adapting stimulus was fixed, suggesting that it did not reflect adaptation to time, which varied with distance. The estimation of spatial and temporal aspects of self-motion is thus processed by partially separable mechanisms, with the distance estimation being similar to the estimation of other magnitude dimensions.

Near-optimal integration of the magnitude information of time and numerosity

“…Single-cell recordings in non-human primates and fMRI studies in humans also indicate the presence of ratioselective neurons in the prefrontal and parietal cortex, regions often associated with the processing of absolute magnitudes [58,59]. By contrast, behavioural studies on cross-dimensional adaptation between space, time and numerosity found null or asymmetrical effects, indicating (partially) separate encoding mechanisms for different magnitudes [60][61][62]. Therefore, a modified view of ATOM might be that absolute magnitudes are initially encoded by (partially) separate mechanisms but are transformed into abstract relative magnitudes (i.e.…”