International Journal of Psychophysiology

The P300 amplitude reduction, or P3AR, is a decrease in the magnitude of the P300 event-related potential (ERP) waveform, typically measured via EEG during oddball tasks, and widely observed in those diagnosed with Alcohol use Disorder (AUD). Though widely acknowledged as a biological correlate of AUD, most of the extant literature on the P3AR features conventional time-domain measurement approaches, and further, the work has predominantly focused on alcohol use specifically. In order to precisely capture the nature of this association as well as assess generalizability to other substances, the current study utilized advanced time-frequency analyses to compare P3 activity in individuals with AUD, cocaine use disorder, and comorbid alcohol and cocaine use. Time-frequency analyses indexed separable theta and delta activity underlying the conventional time-domain P3. Findings revealed that in the conventional time-domain, we observed P3AR shared across alcohol and cocaine use. These findings replicate literature suggesting P3AR associated with substance use. Within time-frequency analyses, we found broad delta reductions across substances, aligning with literature suggesting that delta is mostly comprised of the P3 ERP. For theta-band activity, we found reductions in. amplitude specific to alcohol users only, with no significant diminutions present for cocaine users. As most previous literature focused on alcohol use, unique theta modulations relative to cocaine users provides theoretical clarity in terms of the association of P3AR to substance use more broadly. The findings of the current study highlight the utility of time-frequency measurement approaches in parsing overlapping activity and indexing separable processes with relevance to substance use otherwise unaccounted for in the time domain.

Facial color is associated with the perceptual evaluation of emotions, and compared with faces with original facial or greenish color, reddish angry faces are often judged as having higher emotion intensity. Although perceptual modulation by the relationship between anger and red has also been reported from the perspective of electroencephalography (EEG), how variations in perceived emotion intensity are reflected in brain activity remains unclear. This study investigated whether EEG activity associated with face and facial expression processing is modulated as a function of the interaction between facial color and perceived emotion intensity. In the experiment, we recorded EEGs while participants evaluated emotion intensity using facial stimuli created by combining morph continua from neutral to angry expressions with three types of facial color conditions (original, red, and green). The results revealed that, in the red facial color condition, the early posterior negativity (EPN) amplitude significantly increased as a function of emotion intensity compared with those in the original and green facial color conditions. These findings suggest that the early, automatic affective processing of facial expressions, reflected in the EPN, is modulated by the combination of facial color and emotion intensity. Our findings provide new evidence that early, automatic affective processing of facial expressions, as indexed by the EPN, is modulated by the congruency between high anger intensity and a reddish facial color. HighlightO_LIReddish angry faces increase the ERP component associated with emotion evaluation. C_LIO_LIThe relationship between anger and red is evident in the left hemisphere. C_LIO_LIThe interaction between facial expression and color occurs at a later cognitive processing stage than facial expression or facial color processing alone. C_LI

Introduction - Neurofeedback (NFB) has demonstrated efficacy in treating various disorders, often achieving substantial symptom reductions. Despite its effectiveness, a significant percentage of users (non-responders), fail to benefit from NFB. Addressing this issue, the study at hand investigates the role of NFB design on neuro-physiological responses. Method - event related potentials (ERPs) are examined in response to the application of different aesthetic principles in the context of NFB stimulus design. Drawing from Self-Determination Theory and ERP studies in the field of web design, 16 feedback stimuli were developed according to specific design principles. Stimulus design effects were inspected by means of ERPs allowing for the assessment of implicit and fast electroencephalogram (EEG) reactions. Results of n = 38 participants indicated distinct ERP response patterns at time window of interest 1 (TWOI-1; 100-200 ms) and TWOI-2 (200-300 ms), predicted by beholder-based liking and complexity of stimuli. The findings align with the proposed hypotheses suggesting that aesthetic evaluation of NFB stimuli occurs rapidly and implicitly. In response to the aesthetic vs. non-aesthetic categories, the findings were mixed. The results underscore the importance of further exploration of aesthetic design guidelines in the context of NFB applications. It is discussed how NFB aesthetics relate to Processing Fluency and Affective Prediction Error Theory, while the theoretical methodological issue of the Fixed Effect Fallacy is taken into consideration. The study contributes to the broader understanding of how design elements can affect therapeutic efficacy and engagement in NFB and Human Computer Interaction in therapeutic contexts in general.

Background Cervical rotatory manipulation is commonly used for neck-related symptoms and is often accompanied by a cracking sound. This sound is frequently regarded as a sign of successful manipulation, but whether it contributes substantially to the immediate relaxation response remains unclear. Objective This study examined whether short-term relaxation after cervical rotatory manipulation is more closely related to manipulation-associated sensory input than to the cracking sound cue alone. Methods In this single-session, three-arm, parallel randomized controlled study, 54 healthy volunteers were allocated to cervical rotatory manipulation, sham manipulation, or sham manipulation plus simulated cracking sound. Subjective outcomes were assessed before and after intervention, including positive affect, negative affect, comfort, and satisfaction. Eyes-closed resting-state electroencephalography was recorded before and after intervention. Prespecified neural outcomes included frontal alpha power, frontal alpha/beta ratio, occipital individual alpha frequency, and alpha-band fronto-parietal and fronto-temporal functional connectivity. Results Cervical rotatory manipulation produced greater improvements in positive affect, comfort, and satisfaction than sham manipulation or sham manipulation plus simulated cracking sound, whereas negative affect remained generally stable across groups. These subjective responses were accompanied by short-term electroencephalography changes, particularly in frontal alpha/beta and alpha-band fronto-parietal and fronto-temporal functional connectivity. Changes in frontal alpha/beta ratio were positively associated with changes in positive affect. In contrast, simulated cracking sound alone did not reproduce the full subjective or electroencephalography response observed after real manipulation. Conclusions The immediate relaxation response after cervical rotatory manipulation appears to be more closely related to manipulation-associated sensory input than to the cracking sound cue alone. These findings provide preliminary neurophysiological evidence for distinguishing real manipulation effects from sound-related contextual cues.

Ostracism (i.e., social exclusion) threatens social security and individuals who are hypersensitive to it may face long-term negative mental health consequences. Clarifying how self-reported distress and neural responses to ostracism unfold moment-by-moment and across varying levels of individual traits may help better understand what contributes to hypersensitivity. To this objective, the current study employed a functional near-infrared spectroscopy (fNIRS) adapted Cyberball task and single-trial analytic techniques in a sample of 53 college students (aged 18-22 years). Results confirmed that Cyberball induced ostracism increased self-reported distress and neural activity in the ventrolateral prefrontal cortex (vlPFC), a region associated with emotion regulation. Self-reported distress varied with differences in social anxiety and need for belonging. Moreover, vlPFC activity sensitized across exclusion-specific trials and this neural sensitization was differentially modulated by social anxiety, need for belonging, and personality growth mindset. The current study highlights the value of single-trial approaches for capturing the nuanced temporal dynamics of ostracism responses. Additionally, it underscores the importance of examining how individual differences shape immediate responses to ostracism to better understand their association with downstream, longer-term consequences.

Humans make emotional facial expressions and have a cardiac response when they catch themselves in a mistake or receive feedback about task performance. We tested whether rats exhibit similar visceral responses in the context of metacognition. We assessed heart rate variability (HRV) and machine learning-detected facial expressions as female and male rats detected and stopped in-progress mistakes and received post-choice rewards or error cues. HRV increased during internally detected mistakes, as well as in response to external error cues for both sexes. Errors were associated with an HRV response when parasympathetic tone was higher, while rewards were associated with an HRV response when sympathetic tone was higher. We observed sex-specific effects of cardiac interoception on cognitive control over real-time action correction, in that low parasympathetic tone was associated with reduced ability to stop in-progress mistakes exclusively in females. Rats made facial expressions during mistake detection and in response to task feedback. Outcome-related facial expressions were valence-specific, in that the facial expression after error feedback was delayed relative to the post-reward facial expression. Our results suggest that rats have a visceral experience during metacognitive monitoring.

Summary paragraphA hallmark of learning is the need for sensory stimuli (Ginns, 2015; McGraw et al., 2009; Reinwein, 2012; Spence, 1950) so that learning is fundamentally based on sensory input signals affecting behaviour, physiology, and neurology. If behavioural measures of learning can be causally linked to physiological and neurological variables, a broader understanding of the mechanisms related to learning in schools, learning disabilities, and learning and health issues may emerge (McGraw et al., 2009). Despite decades of research on the physiological/neurological variable of sympathetic activation, learning, and achievement (Horvers et al., 2021), any causal relation remains unclear (Cowley et al., 2014; Mason et al., 2020; Pijeira-Diaz et al., 2016; Sung et al., 2023; Yu et al., 2024) and issues with instrument validation remain (Costantini et al., 2023; Hu et al., 2024; Milstein & Gordon, 2020; Van Der Mee et al., 2021). Here we investigate the effect of sensory input on sympathetic activation by using validated instruments for skin conductance measurement (Batista et al., 2019) and whether sympathetic activation is connected to learning in a cognitive laboratory context and an ecologically valid classroom context. In both contexts, we found a physiological variable which correlated with learning and that sensory input affected this variable while student movement did not. These sensory inputs varied depending on the different instructional activities the students participated in. Together, these findings bring us one step closer to a model linking sensory input to behavioural, physiological, and neurological variables.

Subthreshold depression is associated with significant functional impairment and elevated risk of major depressive disorder. A negative self-concept may disrupt the implicit positive association evoked by ones own face, impairing incidental encoding of self-relevant information. Whether subthreshold depression involves a selective deficit in encoding self-face identity remains unclear. The attribute amnesia paradigm is well suited to address this question because it can dissociate attentional selection from working memory encoding. Using this paradigm, we examined the issue across two experiments. Experiment 1 employed nonsocial stimuli (animal drawings) and confirmed an intact attribute amnesia effect in subthreshold depression (n = 30) comparable to healthy controls (n = 30), ruling out a generalized encoding deficit. Experiment 2 replaced targets with faces (self or other) and revealed a selective enhancement of the attribute amnesia effect for self-face identity in subthreshold depression. Specifically, on the surprise trial, accuracy for self-face identity dropped to near-chance levels in the subthreshold depression group, whereas no such deficit emerged for other-faces or in controls. Encoding recovered rapidly once explicit memory expectations were introduced, indicating intact basic encoding capacity. These findings suggest that subthreshold depression is associated with a specific impairment in incidentally encoding self-face identity. This impairment likely stems from a negative self-concept that weakens self-face salience under incidental encoding conditions. By capturing this selective encoding failure, the present study reveals that the self-processing deficit in subthreshold depression can arise at the gating stage between attention and working memory consolidation.

BackgroundCognitive restructuring, the process of identifying and challenging negative thoughts, is a key technique for treating depressive and anxiety disorders. Although neuroimaging studies have characterised the brain systems supporting cognitive restructuring in healthy individuals, it remains unclear how these systems are altered in depression and anxiety, or whether each disorder is associated with distinct neural dysfunction. MethodsSeventy-three clinical participants with depressive or anxiety disorders and 70 healthy controls completed a cognitive restructuring paradigm during 7 Tesla functional magnetic resonance imaging (fMRI). The task required participants to either repeat a series of negative statements or challenge them using Socratic questioning. Group-level fMRI analyses examined the effects of depressive and anxiety symptom severity on brain activation, while dynamic causal modelling characterized the directional neural influences between implicated regions. ResultsDuring challenging compared to repeating statements, greater depressive symptoms were associated with reduced dorsolateral prefrontal cortex (dlPFC) activation. Conversely, greater anxiety symptoms were associated with greater dlPFC activation. Effective connectivity results revealed that depressive symptoms were associated with greater inhibition from the ventrolateral prefrontal cortex (vlPFC) to the ventromedial prefrontal cortex, whereas anxiety symptoms were associated with greater excitation from the dlPFC to amygdala and greater inhibition from the vlPFC to amygdala. ConclusionsWhile clinical participants modified negative beliefs as effectively as healthy controls, depressive and anxiety symptoms were associated with dissociable neural signatures during restructuring. This suggests that cognitive behavioral therapy may engage partially distinct mechanisms depending on symptom profile, a possibility that warrants longitudinal investigation of treatment response.

Background Emotionally Unstable Personality Disorder (EUPD) is characterised by emotional dysregulation, unstable self-identity, interpersonal difficulties, dissociation, and a high prevalence of non-suicidal self-injury (NSSI). Mental imagery plays a role in emotion processing and autobiographical memory. Yet little is known about the relation between voluntary visual imagery and self-harm in EUPD. The study aimed to examine the imagery characteristics, including visual imagery vividness and synaesthetic-like experiences, and their association with NSSI in EUPD. Method Forty adults aged 18-45 years meeting ICD-10 Diagnostic Criteria for Research (ICD-10 DCR) for EUPD were recruited through purposive sampling. Visual imagery was assessed using the Vividness of Visual Imagery Questionnaire-2 (VVIQ-2). NSSI and its functions were assessed using the Inventory of Statements About Self-Injury (ISAS). Synaesthesia-like experiences were screened using a seven-item questionnaire developed for the study. Group comparisons were performed using independent-samples t-tests, and correlations were assessed using Pearson's correlation coefficient. Results Twenty-nine patients (72.5%) with EUPD had NSSI. Participants with NSSI had significantly higher mean VVIQ-2 scores than those without NSSI (118.48 +/- 24.81 vs. 93.36 +/- 35.66; p = 0.016; Cohen's d = 0.89). VVIQ-2 scores correlated positively with intrapersonal ISAS functions (r = 0.38, p = 0.015) but not interpersonal functions (r = 0.19, p = 0.22). Three participants (7.5%) demonstrated imagery scores compatible with probable hyperphantasia. Four participants reported synaesthesia-like experiences. Conclusions Greater visual imagery was associated with non-suicidal self-harm in patients with EUPD. Imagery vividness was predominantly associated with intrapersonal functions of non-suicidal self-harm, particularly affect regulation, rather than interpersonal motivations. These findings suggest that visual imagery may represent a previously under-recognized cognitive factor contributing to emotional dysregulation and self-injurious behaviour in EUPD. Assessment of imagery characteristics may have clinical relevance when designing psychotherapeutic interventions for EUPD.

Obsessive-compulsive disorder (OCD) is characterized, in part, by repetitive, sequential behaviors, such as cleaning rituals, yet underlying neural circuitry related to abstract sequencing in OCD remains poorly understood. Prior work has implicated a set of cortical regions activated during abstract sequences, which are defined by rules rather than specific stimulus features (Desrochers et al., 2022). These regions include the rostrolateral prefrontal cortex (RLPFC) that is necessary for performance on abstract sequence tasks (Desrochers et al., 2015), as well as the anterior cingulate cortex/dorsolateral prefrontal cortex (ACC/DLPFC), supplementary motor area (SMA), middle temporal gyrus (MTG), and temporo-occipital junction (TOJ) that are differentially activated in OCD compared to healthy participants during abstract sequencing (Doyle et al., 2026). It remains unclear, however, whether these regions form a coordinated circuit, and how their interactions may differ in OCD. In the present study, we examined task based functional and effective connectivity among these regions using a previously published dataset. We tested hypotheses that connectivity within this circuit would be altered in OCD relative to healthy controls (HCs), and that prefrontal regions (ACC/DLPFC and RLPFC) would direct information to downstream regions (SMA, MTG, and TOJ) during a sequential task. We found that connectivity within this circuit differed significantly between groups. HCs exhibited less negative connectivity from the ACC/DLPFC to the TOJ and stronger positive coupling between the MTG and TOJ, as well as stronger coordination between the RLPFC and DLPFC, suggesting coordinated prefrontal control. In contrast, individuals with OCD showed increased connectivity between the RLPFC and MTG, indicating a more direct influence of RLPFC on posterior regions. Effective connectivity analyses further indicated that, across participants, the ACC/DLPFC and MTG function as central hubs of information flow, with task-related inputs entering the circuit via the TOJ, propagating through the MTG to the RLPFC, and subsequently modulating ACC/DLPFC and downstream regions. These findings suggest a shared underlying circuit architecture in OCD and healthy participants despite differences in functional coupling, particularly involving prefrontal cortical regions. Overall, differences arise at the level of functional coordination within a preserved circuit for abstract sequential processing in OCD, adding to current neurobiological models of OCD and suggesting a novel circuit that supports abstract sequencing.

Background: Internet-based cognitive behavioral therapy (iCBT) is efficacious for panic disorder (PD), yet the mechanisms of change remain underspecified. Anxiety sensitivity (AS) is theoretically central to PD maintenance, but its role as a mediator has not been formally tested in Spanish-speaking populations using minimal-contact formats. This study evaluates the efficacy of the "Free from Anxiety" iCBT program and examines AS as a mediator of clinical outcomes. Methods: In a randomized controlled trial, 95 adults meeting DSM-IV-TR criteria for PD were assigned to an 8-week iCBT program with optional email support (n = 49) or a waiting-list control (n = 46). Primary outcome was PD severity (PDSS); secondary outcomes included anxiety sensitivity (ASI-3), general anxiety (BAI), and depression (BDI-II). Mediation was assessed via Baron and Kenny's framework with bootstrapping (5,000 resamples) to estimate the indirect effect of ASI-3 change on PDSS reduction. Results: The treatment group showed significant improvements across all measures compared to controls (PDSS: d = 0.76, 95% CI [0.10, 1.42]; mean d = 1.30). Mediation analysis confirmed that ASI-3 change partially mediated the treatment effect on PDSS (indirect effect = 1.85, 95% CI [0.36, 3.70]), accounting for 27.4% of the total effect. The direct effect remained significant (b = 4.89, p < .001). Intent-to-treat (ITT) analyses supported robustness (d = 0.47 to 1.47). Gains were maintained at 6-month follow-up (d = 1.19 to 1.26). Conclusions: iCBT reduces anxiety sensitivity as a partial mechanism of change, aligning with cognitive models of panic. These findings support Free from Anxiety as an evidence-based, viable first-step intervention for Spanish-speaking clinical populations within stepped-care pathways.

Disordered eating attitudes exist on a continuum that extends well below clinical diagnostic thresholds, yet the cognitive correlates of this non-clinical variation remain incompletely understood. Previous research linking executive functioning to disordered eating in non-clinical samples has relied almost exclusively on self-report questionnaire measures of executive function, which show weak correspondence with performance-based assessments. This methodological reliance leaves open the question of how objective executive performance relates to eating behavior across the spectrum. The present study addressed this gap by examining the association between performance-based measures of executive function and disordered eating attitudes in a non-clinical sample of 243 university students via an online experiment, using a dimensional approach consistent with the Research Domain Criteria framework. Participants completed established neurocognitive tasks covering three executive function domains: working memory was assessed with Digit Span and an N-back task, inhibitory control with a Go/No-Go task, and cognitive flexibility with the Card Sorting Task. Disordered eating attitudes were indexed using the EAT-26 total score and its subscales. A notable correlation was identified between cognitive flexibility and disordered eating attitudes, while working memory and inhibitory control exhibited no such association. Overall, our findings provide evidence for associations between executive functioning and disordered eating attitudes in a non-clinical sample.

Singing is an innate human behaviour present across cultures and the lifespan. Despite lacking direct biological advantages, its ubiquity suggests that it is intrinsically rewarding. This research aimed to investigate the underlying factors that explain variability in sensitivity to deriving reward and enjoyment from natural singing in the general population. In Study 1 (n = 606), an initial pool of items describing daily, non-professional singing behaviours were administered to an international adult sample. Exploratory factor analysis revealed a unidimensional structure of 20 items with acceptable model fit, organized into five facets representing distinct domains of singing-related rewards: 1) pleasure and emotional evocation, 2) social singing reward, 3) singing frequency, 4) mood regulation through singing, and 5) inattentional singing during routine tasks. In Study 2 (n = 430), confirmatory factor analysis in a new sample supported this structure. When both samples were combined (n = 1036), the unidimensional model defined by these five facets showed acceptable to excellent goodness-of-fit indices, supporting the conceptualization of singing reward as a multidimensional construct with differentiated facets. This led to the Barcelona-Aarhus Natural Singing Engagement Questionnaire (BANSEQ), which demonstrated excellent reliability ( = .94) and population-level stability. Study 3 (n = 1036) tested the convergent validity of BANSEQ with measures of music reward and engagement and identified sociodemographic and psychological correlates across the five facets of singing reward. Overall, these findings characterize the sources of individual differences in the hedonic experience of natural singing and propose BANSEQ as a robust psychometric tool for its assessment in the general population.

BackgroundElectroencephalographic (EEG) studies attempting to characterise the neural signature of meditation typically rely on contrasts with passive rest or comparisons among practitioners based on experience. However, these approaches rarely include active control states and seldom establish the reliability and robustness of identified quantitative EEG features. Consequently, the validity of proposed neurophysiological markers of meditative state remains uncertain. The present study addressed these limitations by using a reliability-informed, multi-session within-subject design to characterise distinct state-dependent EEG dynamics in experienced meditators from the Brahmakumaris Rajayoga tradition. MethodsThirty long-term meditators underwent repeated EEG recordings over two days, comprising two meditation sessions per day. Each meditation block was flanked by rest periods, with a cognitive task between sessions to reduce carryover effects. We quantified broadband spectral power, aperiodic slope and intercept, and nonlinear dynamical measures, including detrended fluctuation analysis (DFA), Higuchi fractal dimension, and permutation entropy (PE), across meditation, rest, and task conditions. ResultsCompared with both rest and task states, meditation was associated with increased theta-alpha power, an elevated aperiodic intercept, and systematic modulation of nonlinear indices (DFA, Higuchi, PE). Further meditative core features demonstrated high inter-session test-retest reliability, strong inter-individual consistency, stability across guided and silent meditation states, and were not moderated by years of meditative experience. ConclusionThe present framework identifies a reproducible neurodynamic core of meditation, distinct from passive and active control states, spanning spectral, aperiodic, and nonlinear EEG domains in long-term meditators. These findings enhance the construct validity and measurement reliability of meditation-specific neural markers.

Cognitive flexibility is an executive function that allows individuals to adjust behaviour in response to changing environmental demands. We assessed volitional switching under uncertainty, without rule-based learning, in the Change Your Mind task. Nineteen patients with obsessive-compulsive disorder (OCD), 19 patients with attention-deficit hyperactivity disorder (ADHD) and matched control participants (20 per group) completed the task whilst undergoing a functional MRI scan. The task was a two-alternative forced choice paradigm where each stimulus was presented twice successively, with spurious feedback following the first presentation. This allowed participants the opportunity to repeat or change their response. Participants with ADHD changed their response more frequently than controls following a previously correct response, associated with reduced accuracy on the second trial. This was accompanied with smaller differences between change and repeat trials in the superior frontal gyrus, paracingulate gyrus and frontal pole compared to controls. Participants with OCD did not differ from healthy controls in their performance but exhibited greater activity on both change and repeat trials in the pre- and postcentral gyri than controls. These results point to distinct neurobehavioural differences in patients with ADHD and OCD underlying what is often termed more broadly inflexible behaviour.

Post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD) are chronic psychiatric disorders that have overlapping symptomology and risk factors, including altered motivation and impulsive behavior. Inescapable exposure to a predator odor stressor (2,3,5-Trimethyl-3-Thiazoline (TMT)) produces PTSD-like symptomology in rats. Individual differences in stress-coping behaviors such as freezing and defensive digging during TMT exposure can predict long-term differences in alcohol-related behaviors and altered neurobiology. Here, we sought to evaluate the relationship between stress coping behavior during TMT exposure and different aspects of decision making. In Experiment 1, male and female rats were trained on an adjusting-amounts delay discounting task, and delay discounting curves were established before and >2 weeks after TMT exposure. In Experiment 2, female rats were trained to self-administer alcohol and sucrose in a concurrent choice procedure. Lever responses and preference for alcohol over sucrose were evaluated before and >2 weeks after TMT exposure, and then motivation for competing reinforcers was evaluated using progressive ratios. Active coping (digging) during TMT exposure was correlated with increased post-TMT impulsive choice (Experiment 1), reduced sucrose lever responses both before and after TMT exposure (Experiment 2), and reduced sucrose lever breakpoint (Experiment 2). Additionally, TMT-exposed rats had increased motivation for both alcohol and sucrose self-administration when available concurrently (Experiment 2). Overall, these findings suggest that behavior prior to and during a stressful experience can predict susceptibility to negative effects on decision making, which may help future studies identify the neurobiology underlying risk for aberrant reward-related behaviors after a traumatic event.

Flow, as defined by Mihalyi Csikszentmihalyi (1975), is a holistic sensation experienced when individuals are fully immersed in an activity, resulting in a mental state characterized by a diminished sense of self and altered perception of time. To investigate the global neural dynamics underlying flow, we employed EEG microstate analysis to capture the spatial and temporal properties of dominant transient global brain states (Lehmann et al., 1998). In a study involving 43 participants playing the video game Thumper for 25 minutes, we extracted three four-minute EEG segments from each session corresponding to reported experiences of flow, boredom, and frustration, as determined by self-reports and performance metrics. Across conditions, six distinct microstate topographies (A-F) accounted for most of the global variance. Given that reduced self-referential processing is a key feature of flow, we hypothesized that flow would modulate the properties of microstates C and E, which have been associated with brain regions resembling the default mode network (DMN). Compared to boredom and frustration, the flow condition showed significantly decreased global explained variance, mean duration, time coverage, and occurrence frequency of microstate E, as well as reduced mean duration and time coverage of microstate C. These findings suggest that microstates associated with self-referential processing are shorter and less frequent during flow than during boredom and frustration. This supports the notion that the flow experience modulates global brain dynamics, particularly within the DMN. Furthermore, our results align with previous research reporting reduced DMN activity during meditative and psychedelic states, reinforcing the idea of diminished self-awareness in such conditions.

While cognitive and behavioral manifestations of obsessive-compulsive disorder (OCD) are well known, the neuronal dynamics underlying these symptoms remain poorly understood. Theoretical work suggests that changes in the attractor dynamics of neuronal networks towards increased stability and decreased flexibility might cause behavioral and cognitive symptoms of OCD. We used chronic treatment with the D2 and D3 dopamine receptor agonist quinpirole as a rat model of the disease. In this model, we examined changes in behavioral dynamics and, in a parallel experiment, changes in organization of neuronal activity in the hippocampus and anterior cingulate cortex (ACC). At the behavioral level, we observed increased locomotion and repetitive stereotypical trajectories in quinpirole-treated rats, with frequency of repetitions increasing over the course of the session. At the level of neuronal activity, a gradual increase in the firing rate of ACC neurons within a session paralleled the dynamics of behavioral stereotypy after quinpirole treatment. In quinpirole-treated rats, we observed increased stability in the temporal organization of hippocampal neuronal firing, but no increase in the stability of the spatial organization of discharge. The increased stability of hippocampal firing was observed at both the level of single neurons and coordinated activity of neuronal pairs, and was connected to modulation of activity by theta rhythm. Studying neuronal activity changes underlying behavioral and cognitive manifestations of brain disorders is crucial for understanding and treating brain pathologies. HIGHLIGHTSO_LIDynamics of behavior and neuronal activity was characterized in rats after chronic quinpirole treatment, which is considered a model of obsessive-compulsive disorder. C_LIO_LIThe quinpirole treatment led to repetitive stereotypical trajectories, with increasing frequency of repetitions over the course of a session. C_LIO_LIThe quinpirole treatment was associated with more stable theta modulation of single-cell hippocampal firing within experimental sessions. C_LIO_LIQuinpirole increased stability in cell-pair correlations of hippocampal units within and between sessions. C_LIO_LIQuinpirole led to more stable coordination of local field potential activity between the hippocampus and anterior cingulate cortex at theta frequencies. C_LI

Mental imagery is known to be accompanied by autonomic responses, traditionally viewed as merely downstream consequences of imagery. Recent theoretical work has challenged this view, proposing that mental imagery requires the integration of cortical sensory representations with ascending interoceptive signals supplied by the autonomic nervous system. These two views make opposite predictions: if autonomic activity is only a consequence of imagery, then the responsiveness of the autonomic nervous system should not predict imagery vividness. If instead autonomic input shapes the generation of mental images, individuals with greater autonomic responsiveness should experience more vivid imagery. The present study tested these competing predictions by examining whether individual differences in cardiac vagal reactivity (indexed by the magnitude of HRV change in response to a paced breathing manipulation) predict self-reported visual imagery vividness. Imagery vividness was assessed using the Vividness of Visual Imagery Questionnaire (VVIQ) at a separate time point from the paced breathing protocol, ensuring that any observed relationship between cardiac vagal capacity cannot reflect autonomic activation driven by imagery itself. The key result was that cardiac vagal reactivity (indexed by RMSSD change normalized by mean R-R interval), significantly predicted higher VVIQ scores (r = .30, p = .031). These findings demonstrate that vividness of mental imagery is not exclusively central in origin but also shaped by the capacity of the autonomic nervous system to enter a high-parasympathetic state. Imagery thus likely involves bidirectional autonomic-cortical interaction, with descending pathways triggering the intention to generate an image and ascending interoceptive signals contributing to its generation.