Biology subjects

Zaidel, A.

Publications and source records attributed to Zaidel, A..

11 recordsLinked to original sources

bioRxiv2026

Domain-general computational integration in the Sense of Agency

The Sense of Agency (SoA), the experience of being in control of ones own actions, is thought to emerge from the comparison of internal sensorimotor predictions with afferent feedback. Classical comparator models treat SoA as arising from a prediction-feedback comparison. Volitional action likely engages multiple forward models that predict distinct features of an outcome, such as its timing and spatial trajectory. Whether prediction errors arising from these distinct forward models are integrated into a domain-general representation of agency, and if so by what computational logic, remains unresolved. We addressed this question using a Virtual Reality reaching task. Participants observed a virtual hand replicating their movements while we independently manipulated two sensorimotor domains: temporal delay and spatial angle deviation, in isolation and in factorial combinations. After each trial, participants made an SoA judgment. We examined whether SoA responses show computational hallmarks of integration between different features of sensorimotor prediction. Specifically, we pre-registered three computational models (Multiplicative, Minimum, and Mean) and compared their fit to per-trial responses. Across an exploratory sample (N = 16) and a pre-registered replication (N = 38), SoA declined monotonically with conflict magnitude in both domains. Critically, a Multiplicative integration rule consistently outperformed the Minimum and Mean rules. These results provide direct evidence for domain-general integration between prediction errors in SoA, governed by a multiplicative computational logic.

neuroscience↗

bioRxiv2026

Reassessing Choice Probability: What 59 Macaque Studies Tell Us About Decision-Related Activity in Visual Cortex

Choice probability (CP) quantifies the trial-by-trial covariation between a sensory neurons response and perceptual reports. Despite extensive interest in CP as a window into how perception is linked to the activity of sensory neurons, the usefulness of CP remains debated. On one hand, reported CP magnitudes vary widely across seemingly equivalent studies, questioning its utility as a metric. On the other hand, the absence of clear patterns in CP variability has made it difficult to use it to adjudicate between competing models of visual perception. Here, we performed a meta-analysis of 150 CP estimates from 59 macaque neurophysiology studies to identify factors that systematically influence CP. We confirmed the positive relationship between CP and neuronal sensitivity both across and within individual studies. When controlled for sensitivity, we found remarkable consistency in CP across varying tasks and brain regions with two notable exceptions. First, CPs were higher in tasks involving bistable percepts, reinforcing the link between CP magnitude and subjective perception. Second, CPs were smaller in area V1, supporting prior suggestions about V1s special role in visual processing. We further found a significant effect of stimulus duration on CP, providing evidence against strictly feedforward models and favoring models with substantial feedback and recurrent processing. Finally, we offer recommendations for future studies to enhance the cross-study comparability and theoretical utility of choice signals as the field transitions to large-scale population recordings. More broadly, our findings demonstrate the benefits of meta-studies that expose patterns across many different tasks and animals - yielding insights that complement large-scale population recordings.

neuroscience↗

bioRxiv2025

Augmentation of self-motion perception with synthetic auditory cues

People who suffer from vestibular loss or damage have difficulty maintaining balance and perceiving their own motion in space (self-motion). Sensory augmentation of vestibular information, via other senses, could improve these functions. Here, we tested whether synthetic auditory signals carrying self-motion information can be integrated with vestibular cues. Twenty healthy participants experienced self-motion stimuli in a 3D motion simulator, comprising vestibular (inertial motion), and/or synthetic auditory "motion" cues. The auditory cues, presented via stereo headphones, comprised a series of beeps, with motion speed encoded by beep rate, and heading direction (in the horizontal plane) encoded by simulating the sound to emanate from that direction. In each trial, participants experienced a single-interval self-motion stimulus (vestibular, auditory or combined), and their task was to discriminate its heading direction (two-alternative forced-choice, right/left of straight ahead). A slight heading conflict ({Delta} = {+/-}6{degrees}) was introduced in the combined-cue condition to measure empirical cue weights. Combined auditory-vestibular thresholds were significantly lower (improved) compared to vestibular alone (p < 0.001). But integration was suboptimal - vestibular cues were overweighted, and combined-cue thresholds were larger than predicted by Bayesian-optimal weighting. Interestingly, combined-cue thresholds were better predicted by the empirically observed weights. Thus, humans can integrate synthetic auditory cues with natural vestibular cues to improve self-motion perception. However, synthetic cues are underweighted. This suggests that weighting is determined not only by cue reliability but also by perceived relevance, with (unnatural) synthetic cues potentially considered less relevant to the task. Training might be required to achieve reliability-based integration of synthetic and natural cues.

animal behavior and cognition↗

bioRxiv2025

Unreal? A Behavioral, Physiological, and Computational Model of the Sense of Reality

Our awareness of dreams, hallucinations, and illusions reflects an intriguing human capacity to recognize potentially false perceptions, known as the Sense of Reality (SoR). Though central to mental health, the study of SoR has been hindered by the subjective nature of hallucinatory experiences. Here we employed a novel virtual reality paradigm simulating virtual hallucinations, mirroring the phenomenology of clinical hallucinations. Combining psychophysics, physiological recordings, and computational modeling in one exploratory (n = 31) and one preregistered experiment (n = 32), we found that SoR varied with virtual hallucination magnitude and domain. SoR judgments were associated with distinct motor, pupillary, and cardiac responses, allowing classification of virtual hallucination exposure. We present a computational model in which SoR judgments arise from comparing current sensory input to an internal model of the world. Our results shed light on the age-old question how do we know what is real?

neuroscience↗

bioRxiv2023

Rats rely on airflow cues for self-motion perception

Self-motion perception is a vital skill for all species. It is an inherently multisensory process, that combines inertial (body-based) and relative (with respect to the environment) motion cues. While extensively studied in human and non-human primates, there is currently no paradigm to test self-motion perception in rodents using both inertial and relative self-motion cues. We developed a novel rodent motion simulator using two synchronized robotic arms to generate inertial, relative or combined (inertial and relative) cues of self-motion. Eight rats were trained to perform a task of heading-discrimination, similar to the popular primate paradigm. Strikingly, the rats relied heavily on airflow for relative self-motion perception, with little contribution from optic flow (performance in the dark was almost as good). Relative self-motion (airflow) was perceived with greater reliability vs. inertial. Disrupting airflow (using a fan or windshield) damaged relative, but not inertial, self-motion perception. However, whiskers were not needed for this function. Lastly, the rats integrated relative and inertial self-motion cues in a reliability-based (Bayesian-like) manner. These results implicate airflow as a dominant cue for self-motion perception in rats, and provide a new domain to investigate the neural bases of self-motion perception and multisensory processing in awake behaving rodents.

animal behavior and cognition↗

bioRxiv2022

Contrary neuronal recalibration in different multisensory cortical areas

The adult brain demonstrates remarkable multisensory plasticity by dynamically recalibrating information from multiple sensory sources. When a systematic visual-vestibular heading offset is experienced, the unisensory perceptual estimates recalibrate toward each other (in opposite directions) to reduce the conflict. The neural substrate of this recalibration is unknown. Here, we recorded single-neuron activity from the dorsal medial superior temporal (MSTd), parieto-insular vestibular cortex (PIVC), and ventral intraparietal (VIP) areas in three male rhesus macaques during visual-vestibular recalibration. Both visual and vestibular tuning in MSTd recalibrated-each according to their respective cues perceptual shifts. Vestibular tuning in PIVC also recalibrated together with corresponding perceptual shifts (cells were not visually tuned). By contrast, VIP neurons demonstrated a unique phenomenon: both vestibular and visual tuning recalibrated according to vestibular perceptual shifts. Such that, visual tuning shifted, surprisingly, contrary to visual perceptual shifts. Therefore, while unsupervised recalibration (to reduce cue conflict) occurs in early multisensory cortices, higher-level VIP reflects only a global shift, in vestibular space. In BriefThe neural bases of multisensory plasticity are currently unknown. Here, Zeng et al. studied neuronal recalibration to a systematic visual-vestibular cue conflict. In multisensory cortical areas MSTd and PIVC, single-unit responses to visual and vestibular stimuli recalibrated to reduce the cue conflict, along with their respective unisensory perceptual shifts. By contrast, in higher-level VIP, both visual and vestibular neuronal responses recalibrated with vestibular perceptual shifts. This led to a surprising recalibration of visual responses opposite in direction to visual perceptual shifts. This exposes differential aspects of multisensory plasticity across multisensory cortical areas, and reveals a novel hybrid of visual responses within a vestibular reference frame in parietal neurons. HighlightsO_LIIn the presence of a systematic heading conflict, visual and vestibular cues recalibrate towards one another to reduce the conflict. C_LIO_LIIn MSTd, neuronal responses to vestibular and visual cues recalibrated, each according to their respective cues perceptual shifts. C_LIO_LIIn PIVC, vestibular responses recalibrated according to vestibular perceptual shifts (cells were not visually tuned). C_LIO_LIIn VIP, neuronal responses to both vestibular and visual cues recalibrated together with vestibular perceptual shifts (opposite in direction to visual perceptual shifts). C_LIO_LIProfound differences in neuronal recalibration expose different functions across multisensory cortical areas. C_LI

neuroscience↗

bioRxiv2021

Rapid cross-sensory adaptation of self-motion perception

Perceptual adaptation is often studied within a single sense. However, our experience of the world is naturally multisensory. Here, we investigated cross-sensory (visual-vestibular) adaptation of self-motion perception. It was previously found that relatively long visual self-motion stimuli ({gtrsim} 15s) are required to adapt subsequent vestibular perception, and that shorter duration stimuli do not elicit cross-sensory (visual{leftrightarrow}vestibular) adaptation. However, it is not known whether several discrete short-duration stimuli may lead to cross-sensory adaptation (even when their sum, if presented together, would be too short to elicit cross-sensory adaptation). This would suggest that the brain monitors and adapts to supra-modal statistics of events in the environment. Here we investigated whether cross-sensory (visual{leftrightarrow}vestibular) adaptation occurs after experiencing several short (1s) self-motion stimuli. Forty-five participants discriminated the headings of a series of self-motion stimuli. To expose adaptation effects, the trials were grouped in 140 batches, each comprising three prior trials, with headings biased to the right or left, followed by a single unbiased test trial. Right, and left-biased batches were interleaved pseudo-randomly. We found significant adaptation in both cross-sensory conditions (visual prior and vestibular test trials, and vice versa), as well as both unisensory conditions (when prior and test trials were of the same modality - either visual or vestibular). Fitting the data with a logistic regression model revealed that adaptation was elicited by the prior stimuli (not prior choices). These results suggest that the brain monitors supra-modal statistics of events in the environment, even for short-duration stimuli, leading to functional (supra-modal) adaptation of perception.

neuroscience↗

bioRxiv2020

Overconfidence in visual perception in Parkinson's disease

BackgroundIncreased dependence on visual cues in Parkinsons disease (PD) can unbalance the perception-action loop, impair multisensory integration, and affect everyday function of PD patients. It is currently unknown why PD patients seem to be more reliant on their visual cues. ObjectivesWe hypothesized that PD patients may be overconfident in the reliability (precision) of their visual cues. In this study we tested coherent visual motion perception in PD, and probed subjective (self-reported) confidence in their visual motion perception. Methods20 patients with idiopathic PD, 21 healthy aged-matched controls and 20 healthy young adult participants were presented with visual stimuli of moving dots (random dot kinematograms). They were asked to report: (1) whether the aggregate motion of dots was to the left or to the right, and (2) how confident they were that their perceptual discrimination was correct. ResultsVisual motion discrimination thresholds were similar (unimpaired) in PD compared to the other groups. By contrast, PD patients were significantly overconfident in their visual perceptual decisions (p=0.002 and p<0.001 vs. the age-matched and young adult groups, respectively). ConclusionsThese results suggest intact visual motion perception, but overestimation of visual cue reliability, in PD. Overconfidence in visual (vs. other, e.g., somatosensory) cues could underlie accounts of increased visual dependence and impaired multisensory integration in PD, and could contribute to gait and balance impairments. Future work should investigate PD confidence in somatosensory function. A better understanding of altered sensory reliance in PD might open up new avenues to treat debilitating symptoms.

neuroscience↗

bioRxiv2020

Increased influence of prior choices on perceptual decisions in autism

Autism spectrum disorder (ASD) manifests sensory and perceptual atypicalities. Recent theories suggest that these may reflect a reduced influence of prior information in ASD. Some studies have found reduced adaptation to recent sensory stimuli in ASD. However, the effects of prior stimuli and prior perceptual choices can counteract one-another. Here, we investigated this using two different tasks (in two different cohorts): (i) visual location discrimination, and (ii) multisensory (visual-vestibular) heading discrimination. We fit the data using a logistic regression model to dissociate the specific effects of prior stimuli and prior choices. In both tasks perceptual decisions were biased toward recent choices. Notably, the attractive effect of prior choices was significantly larger in ASD (in both tasks and cohorts), while there was no difference in the influence of prior stimuli. These results challenge theories of reduced priors in ASD, and rather suggest an increased consistency bias for perceptual decisions in ASD.

neuroscience↗

bioRxiv2019

Visual self-motion cues are impaired in Parkinson's disease yet over-weighted during visual-vestibular integration

BackgroundParkinsons disease (PD) is prototypically a movement disorder. Although perceptual and motor functions are interdependent, much less is known about perceptual dysfunction in PD. Perceptual deficits can impact activities of daily living, and contribute to motor symptoms, but might go unnoticed if not tested directly. Posture, gait and balance, affected in PD, rely on veridical perception of ones own motion in space. Yet it is unknown whether self-motion perception is impaired in PD. ObjectivesTo test self-motion perception in PD, separately for visual and vestibular cues (unisensory), and multisensory integration thereof. MethodsParticipants (19 early stage PD, 23 age-matched and 20 young adult controls) experienced vestibular (motion platform), visual (optic flow), and combined visual-vestibular self-motion stimuli, and discriminated whether the stimulus headings were rightward or leftward of straight ahead. PD participants and age-matched controls were tested on two visits (PD on and off medication). ResultsPD participants had significantly impaired visual self-motion perception, both on and off medication. This deficit correlated significantly with clinical disease severity. By contrast, their vestibular performance was unimpaired. Remarkably, despite impaired visual self-motion perception, PD participants significantly over-weighted visual cues during multisensory (visual-vestibular) integration. ConclusionsSelf-motion perception is affected already in early stage PD, specifically by impaired visual (vs. vestibular) function, and by suboptimal visual-vestibular integration. This may contribute to impaired balance and gait control. Future investigation into this connection might open up new avenues for alternative therapies to better treat these symptoms. Furthermore, these results may also impact early PD diagnosis and subtyping.

neuroscience↗

bioRxiv2019

Perceptual decisions are biased toward relevant prior choices

Perceptual decisions are biased by recent perceptual history, a phenomenon termed 'serial dependence.' Using a visual location discrimination task, we investigated what aspects of perceptual decisions lead to serial dependence, and disambiguated the influences of low-level sensory information, prior choices and motor actions on subsequent perceptual decisions. Following several biased (prior) location discriminations, subsequent (test) discriminations were biased toward the prior choices, even when reported via different motor actions, and when prior and test stimuli differed in color. By contrast, biased discriminations about an irrelevant stimulus feature did not substantially influence subsequent location discriminations. Additionally, biased stimulus locations, when color was discriminated, no longer substantially influenced subsequent location decisions. Hence, the degree of relevance between prior and subsequent perceptual decisions is a key factor for serial dependence. This suggests that serial-dependence reflects a high-level mechanism by which the brain predicts and interprets incoming sensory information in accordance with relevant prior choices.

neuroscience↗