Biology subjects

Wiener, M.

Publications and source records attributed to Wiener, M..

3 recordsLinked to original sources

bioRxiv2018

Movement Improves the Quality of Temporal Perception and Decision Making

Recent evidence suggest that our experience of time is directly and intrinsically computed within the motor system. Accordingly, a variety of studies have demonstrated that concurrent movement impacts the estimate of temporal duration, such that perceived time is shifted towards the duration of movement. In order to investigate the role of the motor system, we tested human subjects (n=40) on a novel task combining reaching and time perception. In this task, subjects were required to move a robotic manipulandum to one of two physical locations to categorize a concurrently timed suprasecond auditory stimulus as \"long\" or \"short\", relative to a running average criterion. Critically, subjects were divided into two groups: one in which movement during the interval was unrestricted and subjects could move freely to their choice, and one in which they were restrained from moving until the stimulus interval had elapsed. Our results revealed a higher degree of precision for subjects in the free-moving group. By further decomposing choice and response time data with a drift diffusion model of decision making, we identified the source of this change to a shift in the response threshold for free-moving subjects. Analysis of movement parameters revealed that eventual choice could be determined by movement parameters (e.g. trajectory, force) before the response was made, and even before the interval had elapsed, and that the variability of these movements was lower in the unrestrained group. A further experiment (n=14) verified that these findings were not due to proximity to the target, counting strategies, bias, or movement length. Our findings suggest that perceptual timing may be instantiated within the motor system as an ongoing readout of timing judgment and confidence.

neuroscience↗

bioRxiv2017

Causal role of beta oscillations in time estimation

The neural mechanisms underlying time perception are of vital importance to a comprehensive understanding of behavior and cognition. Recent work has pointed to a supramodal role for beta oscillations in coordinating endogenous timing mechanisms for the purpose of measuring temporal intervals. However, the majority of this work has employed paradigms relying on timed motor responses, which are confounded by betas established role in motor movement. Further, no study to date has tested if the alteration of beta oscillations subsequently impacts timing. Here, we address these concerns and demonstrate for the first time a causal connection between beta oscillations and timing. To accomplish this, we first re-analyzed two, separate EEG datasets from psychophysical experiments (Wiener, et al. 2012; 2015) demonstrating that beta oscillations are associated with the retention and comparison of a memory standard for duration, and that transcranial magnetic stimulation (TMS) of the right supramarginal gyrus leads to an increase in midline beta power during the encoding of a temporal interval, corresponding with a longer perceived interval of time. Next, we conducted a study of 20 healthy human participants using transcranial alternating current stimulation (tACS), over frontocentral cortex, at alpha (10Hz) and beta (20Hz) frequencies, during a visual temporal bisection task, demonstrating that beta stimulation exclusively shifts the perception of time such that stimuli are reported as longer in length, while preserving precision. Finally, we decomposed trial-by-trial choice data with a drift diffusion model of decision making and temporal encoding that reveals the shift in timing is caused by a change in the starting point of accumulation, rather than the drift rate or threshold. Our results provide causal evidence of betas involvement in the perception of time, and point to a specific role for beta oscillations in the encoding and retention of memory for temporal intervals.

neuroscience↗

bioRxiv2017

A Bayesian Perspective on Accumulation in the Magnitude System

Theoretical and empirical work posits the existence of a common magnitude system in the brain. Such a proposal implies that manipulating stimuli in one magnitude dimension (e.g. time) should interfere with the subjective estimation of another magnitude dimension (e.g. space). Here, we asked whether a generalized Bayesian magnitude estimation system would sample sensory evidence using a common, amodal prior. Two psychophysical experiments separately tested participants on their perception of duration, surface, and numerosity when non-target magnitude dimensions and the rate of sensory evidence accumulation were manipulated. First, we found that duration estimation was resilient to changes in surface or numerosity, whereas lengthening (shortening) duration yielded under- (over-) estimations of surface and numerosity. Second, the perception of numerosity and surface were affected by changes in the rate of sensory evidence accumulation, whereas duration was not. Our results suggest that a generalized magnitude system based on Bayesian computations would minimally necessitate multiple priors.

neuroscience↗