Biology subjects

Buot, A.

Publications and source records attributed to Buot, A..

3 recordsLinked to original sources

bioRxiv2026

Pupil Dynamics Reflect Uncertainty-Driven Adjustments of Probability Learning

Adaptive learning in dynamic environments depends on the brains ability to represent and respond to uncertainty. Changes in arousal-mediated pupil diameter provide insight into the neural basis of this process. Prior work has focused on magnitude-based inference tasks, and revealed that learning is primarily influenced by the detection of change points and the corresponding modulation of arousal. In comparison, the role of arousal systems in learning contexts where changes are harder to detect, such as in probability learning, remains poorly understood. Here, we combined pupillometry with a probability learning task in which human participants estimated a hidden generative probability of stimuli that changed abruptly and unpredictably. We adopted a Bayesian ideal observer model to estimate, trial-by-trial, the optimal apparent learning rate and the dynamics of two uncertainty-associated factors - namely, change point probability (the probability that the generative process has abruptly changed) and prior uncertainty (about the current beliefs on this generative process). In line with normative theory, participants heavily relied on prior uncertainty to adjust apparent learning rates. Pupil analyses revealed temporally distinct profiles that separate uncertainty factors: phasic dilations tracked change point probability while tonic pupil dilations tracked prior uncertainty. Mediation analyses further indicated that both phasic and tonic pupil signals at least partially carried the effects of change point probability and prior uncertainty on apparent learning rates, respectively. Together, our results demonstrate that probability learning in a dynamic environment is underpinned by computationally rational integration of latent uncertainty factors, implemented through arousal-associated responses.

neuroscience↗

bioRxiv2019

Fluctuations in the homeostatic neural circuitry influence consistency in choices between cultural goods

Forrest Gump or Matrix? Preference-based decisions are subjective and entail self-reflection. However, these self-related features are unaccounted for by known neural mechanisms of valuation and choice. Self-related processes have been linked to a basic interoceptive biological mechanism, the neural monitoring of heartbeats, in particular in ventromedial prefrontal cortex (vmPFC), a region also involved in value encoding. We thus hypothesized a functional coupling between the neural monitoring of heartbeats and the precision of value encoding in vmPFC. Human participants were presented with pairs of movie titles. They indicated either which movie they preferred, or performed a control objective visual discrimination that did not require self-reflection. Using magnetoencephalography, we measured heartbeat-evoked responses (HERs) before option presentation, and confirmed that HERs in vmPFC were larger when preparing to the subjective, self-related task. We retrieved the expected cortical value network during choice with time-resolved statistical modeling. Crucially, we show that larger HERs before option presentation are followed by stronger value encoding during choice in vmPFC. This effect is independent of the overall vmPFC baseline activity. The neural interaction between HERs and value encoding predicted preference-based choice consistency over time, accounting for both inter-individual differences and trial-to-trial fluctuations within individuals. Neither cardiac activity nor arousal fluctuations could account for any of the effects. HERs did not interact with the encoding of perceptual evidence in the discrimination task. Our results show that the self-reflection underlying preference-based decisions involves the integration of HERs to subjective value encoding in vmPFC, and that this integration contributes to preference stability. Significance statementDeciding whether you prefer Forrest Gump or Matrix is based on subjective values, which only you, the decision-maker, can estimate and compare, by asking yourself. Yet, how self-reflection is biologically implemented and its contribution to subjective valuation are not known. We show that in ventromedial prefrontal cortex, the neural response to heartbeats, an interoceptive self-related process, influences the cortical representation of subjective value. The neural interaction between the cortical monitoring of heartbeats and value encoding predicts choice consistency, i.e. whether you consistently prefer Forrest Gump over Matrix over time. Our results pave the way for the quantification of self-related process in decision making and may shed new light on the relationship between maladaptive decisions and impaired interoception.

neuroscience↗

bioRxiv2018

Neural responses to heartbeats as a mechanism for distinguishing self from other during imagination

Imagination is an internally-generated process, where one can make oneself or other people appear as protagonists of a scene. How does the brain tag the protagonist of an imagined scene, as being oneself or someone else? Crucially, neither external stimuli nor motor feedback are available during imagination to disentangle imagining oneself from imagining someone else. Here, we test the hypothesis that an internal mechanism based on the neural monitoring of heartbeats could distinguish between self and other. 23 participants imagined themselves (from a first-person perspective) or a friend (from a third-person perspective) in various scenarios, while their brain activity was recorded with magnetoencephalography and their cardiac activity was simultaneously monitored. We measured heartbeat-evoked responses, i.e. transients of neural activity occurring in response to each heartbeat, during imagination. The amplitude of heartbeat-evoked responses differed between imagining oneself and imagining a friend, in the precuneus, mid and posterior cingulate regions bilaterally. Effect size was modulated by the general daydreaming frequency of participants but not by their interoceptive abilities. These results could not be accounted for by other characteristics of imagination (e.g., the ability to adopt the perspective, valence or arousal), nor by cardiac parameters (e.g., heart rate) or arousal levels. Heartbeat-evoked responses thus appear as a neural marker distinguishing self from other during imagination.\n\nHighlights- Heartbeat-evoked responses differentiate self from other during imagination.\n\n- These effects were located in the precuneus and mid- to posterior cingulate.\n\n- The neural monitoring of the body could be a mechanism for self/other distinction.

neuroscience↗