Biology subjects

Roach, N. W.

Publications and source records attributed to Roach, N. W..

2 recordsLinked to original sources

bioRxiv2026

Numerosity adaptation reflects multiple levels of sensory processing

Psychophysical and neuroimaging studies have repeatedly suggested that perceived numerosity is susceptible to adaptation, involving high-level number representations. However, whether adaptation to low-level visual features contributes to numerosity adaptation remains unclear. Here, we provide evidence that numerosity adaptation involves not only high- but also low-level visual processing stages. Through a series of psychophysical experiments, we found that the effect of numerosity adaptation was significantly reduced, but not eliminated, when the contrast polarity of stimuli was inverted relative to the preceding adaptor. Follow-up experiments confirmed that the persistence of the aftereffects was not due to retinal adaptation or top-down decision bias. Finally, a computational model incorporating both high- and low-level adaptation successfully reproduced the behavioral pattern. These findings suggest that numerosity adaptation involves at least two stages of visual processing: adaptation to low-level visual features at early sensory stages and to numerosity at higher levels of the visual processing hierarchy. HighlightsO_LINumber adaptation is sensitive to mismatches in contrast polarity C_LIO_LIMismatched stimuli reduce aftereffects but do not eliminate them C_LIO_LIEarly sensory adaptation may modulate higher stage numerosity processing C_LI

neuroscience↗

bioRxiv2023

Body-part specificity for learning of multiple prior distributions in human coincidence timing

During timing tasks, the brain learns the statistical distribution of target intervals and integrates this prior knowledge with sensory inputs to optimise task performance. Daily events can have different temporal statistics (e.g. fastball/slowball in baseball batting), making it important to learn and retain multiple priors. However, the rules governing this process are not yet understood. Here, we demonstrate that the learning of multiple prior distributions in a coincidence timing task is characterised by body-part specificity. In our experiments, two prior distributions (short and long intervals) were imposed on participants. When using only one body part for timing responses, regardless of the priors, participants learned a single prior by generalising over the two distributions. However, when the two priors were assigned to different body parts, participants concurrently learned the two independent priors. Moreover, body-part specific prior acquisition was faster when the priors were assigned to anatomically distant body parts (e.g. hand/foot) than when they were assigned to close body parts (e.g. index/middle fingers). This suggests that the body-part specific learning of priors is organised according to somatotopy.

neuroscience↗