Biology subjects

Pouliot, J. J.

Publications and source records attributed to Pouliot, J. J..

4 recordsLinked to original sources

bioRxiv2025

Bayesian multilevel modeling of group and participant level effect sizes: Stronger inter-individual differences in pupil dilation compared to EEG alpha power during aversive conditioning

Aversive conditioning prompts reliable changes in the power of EEG alpha-band oscillations and pupil dilation. Both variables have been used to test hypotheses on the acquisition, generalization, and extinction of conditioned threat. Existing studies have largely relied on trial averages and group-level analyses. Thus, the variability of these physiological markers to aversive learning at the subject level is currently unknown. Comparisons of group-level analyses in prior studies suggest that pupil dilation and EEG-alpha activity capture complementary information. However, to date, no study has directly compared these two markers in terms of their effect sizes at the level of individual participants. The present study employed Bayesian multilevel modeling to quantify the variability of conditioning effect estimates for alpha-band power and pupillometry. Estimates were examined at the group level and at the participant level, across two conditioning paradigms, involving visual and auditory cues. Although the two metrics shared similar effect sizes at the group level, participant-level variability in these effect sizes was substantially higher for pupil-dilation compared to alpha-power, and this finding was replicated across both paradigms. These findings have important implications for clinical and inter-individual difference research which requires both the quantification of effects at the participant-level as well as meaningful variability between-participants that can be linked to relevant differences such as anxiety.

neuroscience↗

bioRxiv2025

Resolving Competition in Auditory Cortex: Effects of Emotional Content and Misophonia Sensitivity

How the human auditory cortex prioritizes relevant information amid concurrent sounds has been a long-standing question in auditory cognitive neuroscience. The present study used auditory steady-state responses (ASSR) to tag the electrocortical response to a tone embedded in concurrent naturalistic sounds, addressing methodological challenges with overlapping auditory streams. Participants endorsing low (LMS) or high in misophonia symptoms (HMS)--a condition with decreased tolerance to specific, typically orofacial, sounds--were recruited. Sounds varied in their emotional valence (pleasant, neutral, unpleasant, and orofacial) to investigate how emotional content modulates attentional competition and how competition is resolved in listeners with misophonia traits. Affective ratings, alpha-band changes, and pupil dilation in response to the sounds were also assessed. Hypothetical models of competition were tested, revealing a facilitation trend in the ASSR amplitude when accompanied by pleasant and unpleasant, compared to neutral sounds, regardless of misophonia symptoms. However, ASSR was selectively reduced in the HMS but not the LMS group when accompanied by orofacial sounds. Analyses of alpha-band, pupil, and rating data showed that the groups differed primarily in their response to pleasant sounds and orofacial sounds, with the HMS group exhibiting a stronger response to orofacial sounds than the LMS group.

neuroscience↗

bioRxiv2025

Social Anxiety Increases Autonomic and Visuocortical Generalization of Conditioned Aversive Responses to Faces

Aversive generalization learning is an adaptive trait that is necessary for survival in a dynamic environment. However, this process is exaggerated in persons with anxiety disorders, leading to overgeneralization of learned threat associations, hyperreactive fight-or-flight responses, and persistent avoidance. Patients with social anxiety disorder (SAD) exhibit impaired conditioned threat discrimination particularly with respect to social stimuli, such as faces. The present study examined the relationship between social anxiety and generalization of visuocortical and pupil dilation responses to a series of facial morphs, one of which was always paired with a noxious sound. Steady-state visual evoked potentials (ssVEPs; N = 65) increasingly fit a model of generalization, and pupil dilation responses (N = 62) also decreasingly discriminated the CS+ as a function of social anxiety. These results contribute to a growing body of work suggesting that SAD dysregulates the ability of autonomic responses to specifically target social threat. The finding of widened visuocortical tuning in SAD implicates a role of the visual system in driving attentional biases in anxiety disorders, including increased visual processing of safety signals similar to threat cues.

neuroscience↗

bioRxiv2024

Neurophysiological and Autonomic Dynamics of Threat Processing During Sustained Social Fear Generalization

Survival in dynamic environments requires that organisms learn to predict danger from situational cues. One key facet of threat prediction is generalization from a predictive cue to similar cues, ensuring that a cue-outcome contingency is applied beyond the original learning environment. Generalization has been observed in laboratory studies of aversive conditioning: behavioral and physiological processes generalize responses from a stimulus paired with threat (the CS+) to unpaired stimuli, with response magnitudes varying with CS+ similarity. In contrast, work focusing on sensory responses in visual cortex has found a sharpening pattern, in which responses to stimuli closely resembling the CS+ are maximally suppressed, potentially reflecting lateral inhibitory interactions with the CS+ representation. Originally demonstrated with simple visual cues, changes in visuocortical tuning have also been observed in threat generalization learning across facial identities. It is unclear to what extent these visuocortical changes represent transient or sustained effects and if generalization learning requires prior conditioning to the CS+. The present study addressed these questions using EEG and pupillometry in an aversive generalization paradigm involving hundreds of trials using a gradient of facial identities. Visuocortical ssVEP sharpening occurred after dozens of trials of generalization learning without prior differential conditioning, but diminished as learning continued. By contrast, generalization of alpha power suppression, pupil dilation, and self-reported valence and arousal was seen throughout the experiment. Findings are consistent with threat processing models emphasizing the role of changing visucocortical and attentional dynamics when forming, curating, and shaping fear memories as observers continue learning about stimulus-outcome contingencies.

neuroscience↗