Biology subjects

Rainville, P.

Publications and source records attributed to Rainville, P..

10 recordsLinked to original sources

bioRxiv2026

From language to pain: brain-behavior representations of hypnotic verbal suggestions for pain modulation

Language can shape pain by conveying conceptual information about future somatosensory experiences. However, how verbal input is encoded in the brain and how these representations are later implemented during pain modulation remains unclear. We used a standardized hypnotic procedure with fMRI to test how verbal suggestions of hypoalgesia and hyperalgesia (vs neutral control) modulate pain. We quantified convergent neural responses across individuals during both suggestion encoding and pain processing, using inter-subject correlation and multivoxel pattern similarity approaches, respectively, and related these measures to individual differences in hypnotic suggestibility using representational similarity analysis. More suggestible individuals showed similar temporal dynamics in language-related regions during encoding and more similar hypoalgesia-specific patterns in the left parahippocampal gyrus (PHG) during pain. In contrast, lower suggestibility was associated with convergent responses in sensorimotor and monitoring systems across phases, demonstrating different neural implementation in individuals less successful in converting suggestions into hypoalgesia. These findings identify the PHG as a key region linking the effect of verbal suggestions to subsequent pain relief and show that hypnotic suggestibility structures how neural dynamics during language processing translate into altered pain experiences. This study offers a mechanistic lens for understanding how medical hypnosis and language-based therapies influence pain.

neuroscience↗

bioRxiv2026

Increased perceived effort during contralateral thermal heat pain is not explained by increased intracortical and corticospinal inhibition.

BackgroundPain influences motor function and has been proposed to reduce corticospinal and intracortical excitability. At the same time, performance can be maintained during pain, at the cost of increased perceived effort, a centrally generated signal reflecting resource engagement. Here, we tested whether contralateral thermal heat pain-related changes in corticospinal and intracortical excitability contribute to increased effort perception. MethodsIn this preregistered transcranial magnetic stimulation (TMS) study, twenty-one healthy participants received single and paired pulse TMS at rest and during submaximal isometric right wrist flexions performed at 20% maximal peak force. Trials were conducted under a control condition or during contralateral thermal stimulation (painful or non-painful warm) applied to the left forearm. After each contraction, participants rated the intensity of their perceived effort. Corticospinal and intracortical excitability of the right wrist flexor was assessed at rest and during submaximal contractions. ResultsContralateral heat pain significantly increased perceived effort compared with the control and warm conditions. Contralateral heat pain did not reduce corticospinal or intracortical excitability. Conversely, contralateral heat pain increased corticospinal excitability, reflected primarily in decreased cortical silent period duration. Perceived effort was associated with the subjective experience of pain rather than with TMS-derived variables. ConclusionsThese findings suggest that increased effort during contralateral heat pain cannot be attributed to inhibition of the primary motor cortex or the corticospinal pathway. The higher perceived effort in the presence of contralateral heat pain likely reflects the cognitive cost of pain rather than alterations in the transmission of the motor command.

neuroscience↗

bioRxiv2026

Facing pain is effortful: key role of the supplementary motor area and anterior midcingulate cortex

Pain captures attention and interferes with executive and motor processes. In the presence of pain, increasing effort may represent a compensatory mechanism to counteract pain-related disruption and maintain task performance. In this preregistered fMRI study, we investigated neural mechanisms underlying preserved task performance during pain and increased perceived effort. Forty right-handed participants performed a visuomotor force-matching task consisting of isometric handgrip contractions at a low and high force levels under individually calibrated painful or non-painful thermal stimulation. Thermal stimulation was applied to the left forearm, and participants rated the intensity of perceived effort after each isometric contraction. Maintaining task performance under pain was associated with increased perceived effort and recruited brain regions involved in pain modulation and cognitive control. Region-of-interest analysis showed perceived effort was consistently linked to decreased anterior midcingulate cortex activity, whereas supplementary motor area contributions varied depending on its role in motor execution or pain processing. Across experimental condition, motor, pain-modulatory and cognitive-control regions were associated with effort perception. Independently of condition, effort perception was modulated by ventromedial prefrontal cortex and ventral striatum. These findings indicate that effort perception is a complex phenomenon reflecting brain activity within areas involved in motor, executive and valuation processes. Significance StatementThis study advances our understanding of the neural mechanisms underlying task performance under pain and increased effort perception. Brain activity was measured during a visuomotor force-matching task performed in the presence or absence of pain. By contrasting task-related activity between painful and non-painful conditions, we identified regions associated with cognitive control and pain modulation involved in preserving task performance under pain. By correlating activity in regions of interest with ratings of perceived effort, we demonstrated the involvement of the supplementary motor area and midcingulate cortex in effort perception. These findings suggest that additional neural resources are recruited to maintain performance during pain and that the supplementary motor area and midcingulate cortex contribute to heightening the effort experienced.

neuroscience↗

bioRxiv2026

Maintaining performance under pain is effortful: experimental and computational evidence

Pain creates a competing demand on attention, though its impact on performance remains debated. Motivational intensity theory predicts that resource reallocation can preserve output until motivational or capacity limits are reached. Forty adults took part in two preregistered experiments. They completed parallel cognitive (choice reaction, n=20) and motor (isometric hand grip, n=20) tasks at three difficulty levels while receiving warm, low, or high pain heat stimulation on the opposite forearm. Across both domains, participants maintained performance despite painful stimulation. This preservation, however, relied on increased effort mobilization: perceived effort rose with pain intensity, while pain perception decreased during motor and cognitive task execution. Trial wise computational modelling revealed that perceived effort was better predicted by subjective pain experience than by stimulus temperature, supporting a compensatory regulatory mechanism. Thus, maintained performance under pain reflects active resource allocation via effort, generalizable across cognitive and motor domains, but achieved at the cost of increased perceived effort.

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bioRxiv2023

Unravelling the neural dynamics of hypnotic susceptibility: Aperiodic neural activity as a central feature of hypnosis

How well a person responds to hypnosis is a stable trait, which exhibits considerable inter-individual diversity across the general population. Yet, its neural underpinning remains elusive. Here, we address this gap by combining EEG data, multivariate statistics, and machine learning in order to identify brain patterns that differentiate between individuals high and low in susceptibility to hypnosis. In particular, we computed the periodic and aperiodic components of the EEG power spectrum, as well as graph theoretical measures derived from functional connectivity, from data acquired at rest (pre-induction) and under hypnosis (post-induction). We found that the 1/f slope of the EEG spectrum at rest was the best predictor of hypnotic susceptibility. Our findings support the idea that hypnotic susceptibility is a trait linked to the balance of cortical excitation and inhibition at baseline and offers novel perspectives on the neural foundations of hypnotic susceptibility. Future work can explore the contribution of background 1/f activity as a novel target to distinguish the responsiveness of individuals to hypnosis at baseline in the clinic. Significance StatementHypnotic phenomena reflect the ability to alter ones subjective experiences based on targeted verbal suggestions. This ability varies greatly in the population. The brain correlates to explain this variability remain elusive. Addressing this gap, our study employs machine learning to predict hypnotic susceptibility. By recording electroencephalography (EEG) before and after a hypnotic induction and analyzing diverse neurophysiological features, we were able to determine that several features differentiate between high and low hypnotic susceptible individuals both at baseline and during hypnosis. Our analysis revealed that the paramount discriminative feature is non-oscillatory EEG activity before the induction--a new finding in the field. This outcome aligns with the idea that hypnotic susceptibility represents a latent trait observable through a plain five-minutes resting-state EEG.

neuroscience↗

bioRxiv2023

Facial expression is a distinctive behavioural marker of pain processing in the brain

Pain is a private experience observable through various verbal and non-verbal behavioural manifestations, each of which may relate to different pain-related functions. Despite the importance of understanding the cerebral mechanisms underlying those manifestations, there is currently limited knowledge on the neural correlates of the facial expression of pain. In this functional magnetic resonance imaging (fMRI) study, noxious heat stimulation was applied in healthy volunteers and we tested if previously published brain signatures of pain were sensitive to pain expression. We then applied a multivariate pattern analysis to the fMRI data to predict the facial expression of pain. Results revealed the inability of previously developed pain neurosignatures to predict the facial expression of pain. We thus propose a Facial Expression of Pain Signature (FEPS) conveying distinctive information about the brain response to nociceptive stimulations with minimal or no overlap with other pain-relevant brain signatures associated with nociception, pain ratings, thermal pain aversiveness, or pain valuation. The FEPS may provide a distinctive functional characterization of the distributed cerebral response to nociceptive pain associated with the socio-communicative role of non-verbal pain expression. This underscores the complexity of pain phenomenology by reinforcing the view that neurosignatures conceived as biomarkers must be interpreted in relation to the specific pain manifestation(s) predicted and their underlying function(s). Future studies should explore other pain-relevant manifestations and assess the specificity of the FEPS against simulated pain expressions and other types of aversive or emotional states.

neuroscience↗

bioRxiv2023

Pain reflects the informational value of nociceptive inputs.

Pain perception and its modulation are fundamental to human learning and adaptive behavior. This study investigated the hypothesis that pain perception is tied to pains learning function. Thirty-one participants performed a threat conditioning task where certain cues were associated with a possibility of receiving a painful electric shock. The cues that signalled potential pain or safety were regularly changed, requiring participants to continually establish new associations. Using computational models, we quantified participants pain expectations and prediction errors throughout the task and assessed their relationship with pain perception and electrophysiological responses. Our findings suggest that subjective pain perception increases with prediction error, that is when pain was unexpected. Prediction errors were also related to physiological nociceptive responses, including the amplitude of the nociceptive flexion reflex and EEG markers of cortical nociceptive processing (N2-P2 evoked potential and gamma-band power). Additionally, higher pain expectations were related to increased late event-related potential responses and alpha/beta decreases in amplitude during cue presentation. These results further strengthen the idea of a crucial link between pain and learning and suggest that understanding the influence of learning mechanisms in pain modulation could help us understand when and why pain perception is modulated in health and disease.

neuroscience↗

bioRxiv2022

Distinct trajectories in low-dimensional neural oscillation state space track dynamic decision-making in humans

The brain evolved to govern behavior in a dynamic world, in which pertinent information about choices is often in flux. Thus, the commitment to an action choice must reflect a balance between monitoring that information and the necessity to act before opportunities are lost. Here, we investigate the mechanisms of dynamic decision-making in humans using low dimensional space representation of brain wide magnetoencephalography recordings. We show that the principal components (PCs) of alpha (9-13 Hz) and beta power (16-24 Hz) are involved in tracking sensory information evolving over time in the sensorimotor and visual cortex. We also found that alpha PCs reflect the commitment to a particular choice, while beta PCs reflect motor execution. Finally, higher frequency components in subcortical areas reflect the adjustment of speed- accuracy tradeoff policies. These results provide a new detailed characterization of the distributed oscillatory brain processes underlying dynamic decision-making in humans.

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bioRxiv2021

Pharmacological blockade of muscle afferents and perception of effort: a systematic review with meta-analysis

BackgroundThe perception of effort (PE) provides information on task difficulty and influences physical exercise regulation and human behavior. This perception differs from other-exercise related perceptions such as pain. There is no consensus on the role of group III-IV muscle afferents as a signal processed by the brain to generate PE. ObjectiveThe aim of this meta-analysis was to investigate the effect of pharmacologically blocking muscle afferents on the PE. MethodsSix databases were searched to identify studies measuring the ratings of perceived effort (RPE) during physical exercise, with and without pharmacological blockade of muscle afferents. Articles were coded based on the operational measurement used to distinguish studies in which PE was assessed specifically (effort dissociated) or as a composite experience including other exercise-related perceptions (effort not dissociated). Articles that did not provide enough information for coding were assigned to the unclear group. ResultsThe effort dissociated group (n=6) demonstrated a slight RPE increase with reduced muscle afferents feedback (standard mean change raw (SMCR), 0.39; 95%CI, 0.13 to 0.64). The group effort not dissociated (n=2) did not reveal conclusive results (SMCR, -0.29; 95%CI, -2.39 to 1.8). The group unclear (n=8) revealed a slight RPE decrease with reduced muscle afferents feedback (SMCR, -0.27; 95%CI, -0.50 to -0.04). ConclusionsThe heterogeneity in results between groups reveals that the inclusion of perceptions other than effort in its rating influences the RPE scores reported by the participants. The absence of decreased RPE in the effort dissociated group suggests that muscle afferents feedback is not a sensory signal of PE. Key pointsO_LITo date, there is no consensus on the neurophysiological signal processed by the brain to generate the perception of effort. C_LIO_LIFollowing a systematic search in six databases, this meta-analysis suggests that reducing afferent feedback from the working muscles via epidural anesthesia does not reduce perception of effort. C_LIO_LIThis systematic review suggests that afferent feedback from the working muscles is not the neurophysiological signal processed by the brain to generate the perception of effort. C_LI

neuroscience↗

bioRxiv2021

The aversive value of pain in human decision-making

According to basic utilitarian principles, people should try to maximize rewards and minimize pain. Here, participants were put in a situation where monetary rewards were paired to electric shocks spanning between pain detection and tolerance thresholds. Monetary offers ranged linearly from $0 to $5 or $10 in Group1 and 2, respectively, and exponentially from $0 to $5 in Group3. The value of pain increased quadratically as a function of the anticipated pain intensity. While increasing the range of monetary offers increased the price requested to accept pain, skewing the distribution of rewards encouraged profit maximization. Participants scoring higher on harm avoidance and lower on persistence scales requested more money to accept pain. Accepting highly painful offers slowed decisions regardless of the value of the concurrent reward. Altogether, pain-related decisions are highly relative to the local range of available rewards and may be under the control of more automatic avoidance mechanisms.

neuroscience↗