Biology subjects

Wiener, M.

Publications and source records attributed to Wiener, M..

At least 19 recordsLinked to original sources

bioRxiv2026

The Impact of Noise on Memorability in Minds and Machines

Some images are consistently remembered better than others, a stimulus property known as memorability, and deep neural networks (DNNs) are increasingly used to estimate it in place of human observers. A recent account proposes that memorable images are processed more efficiently. We argue that memorability can also be viewed as signal quality, and that efficient processing should therefore be robust to noise. Comparing memorability estimates from state-of-the-art (SOTA) models with human performance in continuous recognition tasks, we found that the two consistently diverged in how memorability changed as images were degraded by increasing levels of Gaussian noise and blur, such that models under-estimated high memorability images with noise, while over-estimating low memorability images with noise, a pattern resembling stochastic resonance. In contrast, noise degraded memorability estimates in humans, yet high memorability images were resistant to this effect. We discovered this divergence arose because conventional models are influenced by how noise alters their attention across images, whereas humans learn how images relate to one another. Building on these findings, we developed GraphMem, a model that estimates memorability from the relational structure among images rather than from the features of individual images. GraphMem outperformed SOTA models in estimating memorability under noise and blur and aligned most closely with human data. These findings caution against relying on conventional DNN-based memorability estimates for novel images, and suggest that modeling the relational structure in vision models yields more human-like memorability estimates.

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bioRxiv2026

Blinded by motion: Electrophysiological decoupling of time dilation and confidence

The duration of visual stimuli can be altered by stimulus features, such as size, brightness, and motion. Recently, we observed that motion-induced changes in perceived duration also shift confidence judgments, but do not track awareness of the illusion. How these two effects differ and are instantiated neurally are unknown. We investigated this question by replicating our previous finding, in which human subjects (n=27) performed a temporal bisection task where they were asked to classify the duration (1-3.5s) of a walking stickman figure with different velocities and provide confidence judgments while 64-channel electroencephalogram (EEG) activity was recorded. Behavioral findings replicated the previous time dilation effect where progressively faster walking speeds led to longer perceived durations. A similar shift was observed for confidence ratings, yet with lowest confidence for the medium walking speed, indicating a metacognitive inability to monitor dilation. Furthermore, common EEG signatures of time perception, such as the late positive component of timing (LPCt) and contingent negative variation (CNV) did not vary with walking speed. Instead, onset-locked responses over occipital electrodes covaried with walking speed and correlated with subject-level shifts in psychometric functions, but not with confidence; conversely, frontocentral responses covaried with confidence judgments, but not walking speed. These findings suggest that temporal illusions are engaged by sensory processes that fail to reach the metacognitive level and that confidence judgments, in turn, are driven by motor estimates read out from frontocentral regions

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bioRxiv2025

The Speed Limit of Visual Perception: Bidirectional influence of image memorability and processing speed on perceived duration and memory recall

Visual stimuli are known to vary in their perceived duration, with some stimuli engendering so-called "time dilation" and others "time compression" effects. Previous theories have suggested these effects rely on the level of attention devoted to stimuli, magnitude of the stimulus dimension, or intensity of the population neural response, yet cannot account for the full range of experimental effects. Recently, we demonstrated that perceived time is affected by the image properties of scene clutter, size, and memorability (Ma, et al. 2024), with the former compressing and latter two dilating duration. Further, perceived duration also predicted recall of images 24h later, on top of memorability. To explain the memorability effect, we found that a recurrent convolutional neural network (rCNN) could recapitulate the time dilation effect by indexing the rate of entropy collapse, or "speed", across successive timesteps, with more memorable stimuli associated with faster speeds. Here, we replicate and extend these findings via three experiments (n=20ea.) where subjects performed a sub-second temporal bisection task using memorability stimuli with increasing memorability, but a constant speed (exp 1), increasing speed, but constant memorability (exp 2), or increasing in both (exp 3), each followed by a surprise memory test 24hr later. We found that either increasing memorability or speed alone led to time dilation effects, with faster/slower speeds shifting memory recall by [~]8.4% in either direction. However, when both metrics increased, memorability dilated time while speed compressed it, while still improving recall overall. These findings can be explained by a model wherein the visual system is tuned to a preferred speed for processing stimuli that scales with the magnitude of visual response, such that stimuli closer to this speed are dilated in time. Overall, these findings provide a new lens for interpreting time dilation/compression effects and how visual stimuli are prioritized at temporal scales. Author SummaryRecent work has demonstrated a link between perceived duration and memory recall, with memorable images dilating time, and perceived duration in turn affecting memory. The link between these two can be indexed by the speed at which images are processed in recurrent convolutional neural networks, yet the limits of this link remain untested. Here, we tested three groups on a timing task using three sets of stimuli selected according to both their memorability and speed. We find that when one factor is held constant, both memorability and speed still dilate perceived duration, with speed alone accounting for a shift in memory recall of [~]17%. However, when speeds are raised to their highest limits, perceived duration is instead compressed. An inverted-U shape rule between time dilation and compression over speed that is moderated by memorability explains this effect and suggests the visual system shifts between these modes to both gather more information and conserve energy, respectively.

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bioRxiv2024

An Entrainment Oscillator Mechanism underlies Human Beat Matching Performance

Humans possess an innate ability to effortlessly entrain to auditory rhythms, which previous theories have linked to the supplementary motor area (SMA). Yet, whether entrainment, as measured by electrophysiological (EEG) recordings reflects actual processing of rhythms or merely a reflection of their periodical nature, is unknown. Here we conducted tested human participants on a novel beat matching task, in which they listened to two simultaneous tempos and asked to modulate the rate of a variable tempo (1.67-2.34 Hz between trials) to match a constant target tempo (2 Hz). EEG recordings exhibited entrainment to both frequencies at frontocentral electrodes that shifted into alignment over the course of each trial Behaviorally, participants tended to anchor the matched tempo to the starting comparison frequency, such that they underestimated the tempo for slower initial conditions and overestimated for faster initial conditions; further, tempo judgments were shifted away from the variable tempo on the previous trial. A model of phase-coupled oscillators, in which both tempos were pulled towards one another, replicated both effects. This model further predicted that by strengthening the coupling strength of the constant tempo oscillator, both bias effects could be eliminated. To test this, a second group of subjects underwent transcranial alternating current stimulation (tACS) to the SMA phase-locked to the target tempo at 2 Hz. Consistent with model predictions, tACS attenuated both behavioral effects. Overall, these results provide causal support to the role of the SMA in entrainment during human beat matching.

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bioRxiv2023

Memorability shapes perceived time (and vice versa)

Visual stimuli are known to vary in their perceived duration. Likewise, some visual stimuli are also known to linger for longer in memory. Yet, whether or not these two features of visual processing are linked is unknown. Despite early assumptions that time is an extracted, or higher-order feature of perception, more recent work over the past two decades has demonstrated that timing may be instantiated within sensory modality circuits. A primary location for many of these studies is the visual system, where duration sensitive responses have been demonstrated. Further, visual stimulus features have been observed to shift perceived duration. These findings suggest that visual circuits mediate or construct perceived time. Here, we present across a series of experiments evidence that perceived time is affected by the image properties of scene size, clutter, and memorability. More specifically, we observe that scene size and memorability dilate time, whereas clutter contracts it. Further, the durations of more memorable images are also perceived more precisely. Conversely, the longer the perceived duration of an image, the more memorable it is. To explain these findings, we applied a recurrent convolutional neural network (rCNN) model of the ventral visual system, in which images are progressively processed over time. We find that more memorable images are processed faster, and that this increase in processing speed predicts both the lengthening and increased precision of perceived durations. These findings thus provide a new avenue in vision research towards the study of perceived image durations as means of explaining visual system responses.

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bioRxiv2023

Tremors in Time: Mechanically Induced Motor Tremors Influence

Contemporary research has begun to show a strong relationship between movements and the perception of time. More specifically, concurrent movements serve to both bias and enhance time estimates. To explain these effects, we recently proposed a mechanism by which movements provide a secondary channel for estimating duration that is combined optimally with sensory estimates, in accordance with Bayesian cue combination. However, a critical test of this framework is that by introducing "noise" into movements, sensory estimates of time should similarly become noisier in a manner predicted by cue combination equations. To accomplish this, we had human participants move a robotic arm while estimating intervals of time in either auditory or visual modalities (n=24, ea.). Crucially, we introduced an artificial "tremor" in the arm while subjects were moving, that varied across three levels of amplitude (1-3 N) or frequency (4-12 Hz). The results of both experiments revealed that increasing the frequency of the tremor led to noisier estimates of duration, but in such a way that higher levels of noise saturated the impact, consistent with optimal integration. Further, the effect of noise varied with the base precision of the interval, such that a naturally less precise timing (i.e. visual) was more influenced by the tremor than a naturally more precise modality (i.e. auditory). To explain these findings, we fit the data with a recently developed drift-diffusion model of perceptual decision making, in which the momentary, within-trial variance was allowed to vary across conditions. Here, we found that the model could recapitulate the observed findings, further supporting the theory that movements influence perception directly. Overall, our findings support the proposed framework, and demonstrate the utility of inducing motor noise via artificial tremors, thus providing clinical utility in their connection to movement disorders characterized by tremors.

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bioRxiv2023

Neuroimaging Signatures of Metacognitive Improvement in Sensorimotor Timing

Error monitoring is an essential human ability underlying learning and metacognition. In the time domain, humans possess a remarkable ability to learn and adapt to temporal intervals, yet the neural mechanisms underlying this are not well understood. Recently, we demonstrated that humans exhibit improvements in sensorimotor time estimates when given the chance to incorporate feedback from a previous trial (Bader and Wiener 2021), suggesting that humans are metacognitively aware of their own timing errors. To test the neural basis of this metacognitive ability, human participants of both sexes underwent fMRI while they performed a visual temporal reproduction task with randomized suprasecond intervals (1-6s). Crucially, each trial was repeated following feedback, allowing a "re-do" to learn from the successes or errors in the initial trial. Behaviorally, we replicated our previous finding that subjects improve their performance on re-do trials despite the feedback being temporally uninformative (i.e. early or late). For neuroimaging, we observed a dissociation between estimating and reproducing time intervals, with the former more likely to engage regions associated with the default mode network (DMN), including the superior frontal gyri, precuneus, and posterior cingulate, whereas the latter activated regions associated traditionally with the "Timing Network" (TN), including the supplementary motor area (SMA), precentral gyrus, and right supramarginal gyrus. Notably, greater DMN involvement was observed in Re-do trials. Further, the extent of the DMN was greater on re-do trials, whereas for the TN it was more constrained. Finally, Task-based connectivity between these networks demonstrated higher inter-network correlation on initial trials, but primarily when estimating trials, whereas on re-do trials communication was higher during reproduction. Overall, these results suggest the DMN and TN work in concert to mediate subjective awareness of ones sense of time for the purpose of improving timing performance. Significance StatementA finely tuned sense of time perception is imperative for everyday motor actions (e.g., hitting a baseball). Timing self-regulation requires correct assessment and updating duration estimates if necessary. Using a modified version of a classical task of time measurement, we explored the neural regions involved in error detection, time awareness, and learning to time. Reinforcing the role of the SMA in measuring temporal information and providing evidence of co-activation with the DMN, this study demonstrates that the brain overlays sensorimotor timing with a metacognitive awareness of its passage.

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bioRxiv2022

The role of consciously timed movements in shaping and improving auditory timing

Our subjective sense of time is intertwined with a plethora of perceptual, cognitive, and motor functions, and likewise, the brain is equipped to expertly filter, weight, and combine these signals for seamless interactions with a dynamic world. Until relatively recently, the literature on time perception has excluded the influence of motor activity, yet, it has been found that motor circuits in the brain are at the core of most timing functions. Several studies have now identified that concurrent movements exert robust effects on perceptual timing estimates, but critically, have not assessed how humans consciously judge the duration of their own movements. This creates a gap in our understanding of the mechanisms driving movement-related effects on sensory timing. We sought to address this gap by administering a sensorimotor timing task in which we explicitly compared the timing of isolated auditory tones and arm movements, or both simultaneously. We contextualized our findings within a Bayesian cue combination framework, in which separate sources of temporal information are weighted by their reliability and integrated into a unitary time estimate that is more precise than either unisensory estimate. Our results revealed differences in accuracy between auditory, movement, and combined trials, and crucially, that combined trials were the most accurately timed. Under the Bayesian framework, we found that participants combined estimates were more precise than isolated estimates in a way that trended towards optimality, while being overall less optimal than the models prediction. These findings elucidate previously unknown qualities of conscious motor timing, and proposes computational mechanisms that can describe how movements combine with perceptual signals to create unified, multimodal experiences of time.

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bioRxiv2022

Anchors for Time, Distance, and Magnitude in Virtual Movements

In order to navigate through the environment, humans must be able to measure both the distance traveled in space, and the interval covered in time. Yet, how these two dimensions are computed and interact across neural systems remains unknown. One possibility is that subjects measure how far and how long they have traveled relative to a known reference point, or anchor. To measure this, we had human participants (n=24) perform a distance estimation task in a virtual environment in which they were cued to attend to either the spatial or temporal interval traveled, while responses were measured with multiband fMRI. We observed that both dimensions evoked similar frontoparietal networks, yet with a striking rostrocaudal dissociation between temporal and spatial estimation. Multivariate classifiers trained on each dimension were further able to predict the temporal or spatial interval traveled, with centers of activation within the supplementary motor area (SMA) and retrosplenial cortex (RSC) for time and space, respectively. Further, a cross-classification approach revealed the right supramarginal gyrus (SMG) and occipital place area (OPA) as regions capable of decoding the general magnitude of the traveled distance. Altogether, our findings suggest the brain uses separate systems for tracking spatial and temporal distances, which are combined together along with amodal estimates.

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bioRxiv2021

Context and Phase Dependent Effects of Delta transcranial Alternating Current Stimulation on Dynamic Attending

Attention requires the allocation of limited resources to properly interpret our environment, making it ultimately unsustainable. Dynamic Attending Theory suggests that, in order to realistically maintain vigilance to our surroundings, attention likely fluctuates between high and low energetic states, such that information can be processed more quickly and accurately during attentional peaks and vice versa. Additionally, prior studies have suggested that the phase of delta oscillations (1-4 Hz) are critically involved in the entrainment of attention. We investigated the physiological and behavioral entrainment of attention and the role that delta phase plays to moderate the benefits of this attending. Participants (N=28) passively listened to a background auditory rhythm and were required to complete a visual discrimination task while undergoing 2 Hz transcranial alternating current stimulation (tACS). The task involved identifying an image, either upright or inverted, presented either on or before the final beat, while receiving delta stimulation that was either aligned or unaligned with image presentation. As expected, reaction times (RTs) were faster for on-beat than off-beat stimuli, and for upright images than inverted. Crucially, tACS phase-aligned with the beat led to faster RTs over out-of-phase stimulation, but only for upright images; remarkably, this pattern was reversed for inverted images presented on-beat, with slower RTs for inverted stimuli during in-phase tACS. These results suggest that the effects of delta tACS are both phase and context dependent, and mediate a potential form of speed-accuracy tradeoff in the allocation of attentional resources during rhythmic entrainment.

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bioRxiv2020

Slowing the Body slows down Time (Perception)

Interval timing is a fundamental component action, and is susceptible to motor-related temporal distortions. Previous studies have shown that movement biases temporal estimates, but have primarily considered self-modulated movement only. However, real-world encounters often include situations in which movement is restricted or perturbed by environmental factors. In the following experiments, we introduced viscous movement environments to externally modulate movement and investigated the resulting effects on temporal perception. In two separate tasks, participants timed auditory intervals while moving a robotic arm that randomly applied four levels of viscosity. Results demonstrated that higher viscosity led to shorter perceived durations. Using a drift-diffusion model and a Bayesian observer model, we confirmed these biasing effects arose from perceptual mechanisms, instead of biases in decision making. These findings suggest that environmental perturbations are an important factor in movement-related temporal distortions, and enhance the current understanding of the interactions of motor activity and cognitive processes.

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bioRxiv2020

Modulation of Individual Alpha Frequency with tACS shifts Time Perception

Previous studies have linked brain oscillation and timing, with evidence suggesting that alpha oscillations (10Hz) may serve as a "sample rate" for the visual system. However, direct manipulation of alpha oscillations and time perception has not yet been demonstrated. Eighteen subjects performed a time generalization task with visual stimuli. Participants first learned the standard intervals (600 ms) and then were required to judge the new temporal intervals if they were equal or different compared to the standard. Additionally, we had previously recorded resting-state EEG from each subject and calculated their Individual Alpha Frequency (IAF), estimated as the peak frequency from the mean spectrum over posterior electrodes between 8 and 13 Hz. After learning the standard interval, participants performed the time generalization task while receiving occipital transcranial Alternating Current Stimulation (tACS). Crucially, for each subject, tACS was administered at their IAF or at off-peak alpha frequencies (IAF{+/-}2 Hz). Results demonstrated a linear shift in the psychometric function indicating a modification of perceived duration, such that progressively "faster" alpha stimulation led to longer perceived intervals. These results provide the first evidence that direct manipulations of alpha oscillations can shift perceived time in a manner consistent with a clock speed effect.

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bioRxiv2020

Multiplexing of EEG signatures for temporal and spatial distance estimates

The perception and measurement of spatial and temporal dimensions have been widely studied. However, whether these two dimensions are processed independently is still being debated. Additionally, whether EEG components are uniquely associated with time or space, or whether they reflects a more general measure of magnitude remains unknown. While undergoing EEG, subjects traveled a randomly predetermined spatial or temporal interval and were then instructed to reproduce the interval traveled. In the task, the subjects travel speed varied for the estimation and reproduction phases of each trial, so that one dimension could not inform the other. Behaviorally, subject performance was more variable when reproducing time than space, but overall, just as accurate; notably, behavior was not correlated between tasks. EEG data revealed during estimation the contingent negative variation (CNV) tracked the probability of the upcoming interval, regardless of dimension. However, during reproduction, the CNV exclusively oriented to the upcoming temporal interval at the start of reproduction. Further, a dissociation between relatively early frontal beta and late posterior alpha oscillations was observed for time and space reproduction, respectively. Our findings indicate that time and space are neurally separable dimensions, yet are hierarchically organized across task contexts within the CNV signal.

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bioRxiv2020

From ATOM to GradiATOM: Cortical gradients support time and space processing as revealed by a meta-analysis of neuroimaging studies

According to the ATOM (A Theory Of Magnitude), formulated by Walsh more than fifteen years ago, there is a general system of magnitude in the brain that comprises regions, such as the parietal cortex, shared by space, time and other magnitudes (Walsh, 2003). The present meta-analysis of neuroimaging studies used the Activation Likelihood Estimation (ALE) method in order to determine the set of regions commonly activated in space and time processing and to establish the neural activations specific to each magnitude domain. Following PRISMA guidelines, we included in the analysis a total of 112 and 114 experiments, exploring space and time processing, respectively. We clearly identified the presence of a system of brain regions commonly recruited in both space and time and that includes: bilateral insula, the pre-supplementary motor area (SMA), the right frontal operculum and the intraparietal sulci. These regions might be the best candidates to form the core magnitude neural system. Surprisingly, along each of these regions but the insula, ALE values progressed in a cortical gradient from time to space. The SMA exhibited an anterior-posterior gradient, with space activating more-anterior regions (i.e., pre-SMA) and time activating more-posterior regions (i.e., SMA-proper). Frontal and parietal regions showed a dorsal-ventral gradient: space is mediated by dorsal frontal and parietal regions, and time recruits ventral frontal and parietal regions. Our study supports but also expands the ATOM theory. Therefore, we here re-named it the GradiATOM theory (Gradient Theory of Magnitude), proposing that gradient organization can facilitate the transformations and integrations of magnitude representations by allowing space- and time-related neural populations to interact with each other over minimal distances.

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bioRxiv2020

Dissociable Effects of Emotional Stimuli on Perception and Decision-Making for Time

Previous research has demonstrated that negative emotional faces dilate time perception, however, the mechanisms underlying this phenomenon are not fully understood. Previous attempts focus on the pacemaker-accumulator model of time perception, which includes a clock, memory, and decision-making stage, wherein emotion affects one of these stages; possibly by increasing pacemaker rate via arousal, increasing accumulation rate via attention, or by biasing decision-making. To further investigate the stage(s) that emotion is affecting time perception we conducted a visual temporal bisection task with sub-second intervals while recording 64-channel electroencephalogram (EEG). To separate the influence of face and timing responses the temporal stimulus was preceded and followed by a face stimulus displaying a neutral or negative expression creating three trial-types: Neg[->]Neut, Neut[->]Neg, or Neut[->]Neut. The data revealed a leftward shift in bisection point (BP) in Neg[->]Neut and Neut[->]Neg suggesting an overestimation of time. Neurally, we found the face-responsive N170 component was larger for negative faces and the N1 and contingent negative variation (CNV) were larger when preceded by a negative face. We also found an interaction effect between condition and response for the late positive component of timing (LPCt) and a significant difference between response (short/long) in the neutral condition. We conclude that a preceding negative face affects the clock stage leading to more pulses being accumulated, either through attention or arousal, as indexed by a larger N1, CNV, and N170; whereas viewing the negative face second biased decision-making leading to "short" responses being less likely, as evidenced by the LPCt.

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bioRxiv2019

State-dependent differences in the frequency of TMS-evoked potentials

Previous evidence suggests different cortical areas naturally oscillate at distinct frequencies, reflecting tuning properties of each region. The concurrent use of transcranial magnetic stimulation (TMS) and electroencephalography (EEG) has been used to perturb cortical regions, resulting in an observed post-stimulation response that is maximal at the natural frequency of that region. However, little is known about the spatial extent of TMS-induced activation differences in cortical regions when comparing resting state (passive) versus active task performance. Here, we employed TMS-EEG to directly perturb three cortical areas in the right hemisphere while measuring the resultant changes in maximal evoked frequency in healthy human subjects during a resting state (N=12) and during an active sensorimotor task (N=12). Our results revealed that the brain engages a higher dominant frequency mode when actively engaged in a task, such that the frequency evoked during a task is consistently higher across cortical regions, regardless of the region stimulated. These findings suggest that a distinct characteristic of active performance versus resting state is a higher state of natural cortical frequencies.

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bioRxiv2019

TMS-evoked oscillations in human cortical circuits: A search for natural frequencies

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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.

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