Biology subjects

Cahart, M.-S.

Publications and source records attributed to Cahart, M.-S..

3 recordsLinked to original sources

bioRxiv2026

Shared Neural Responses and Individualised Emotional Experience: An fMRI Study of Music Listening and Anhedonia

Anhedonia, the diminished capacity to experience pleasure, is a core symptom of depressive disorders and is linked to altered reward, salience, and affective processing. However, whether individual differences in anhedonia are associated with variance in neural responses during naturalistic emotional experiences remains unclear. This study examined neural synchrony, subjective emotional similarity, and continuous anhedonia-related variation in 28 healthy young adults who listened to emotionally evocative classical music during fMRI. Participants listened to happy, sad, and neutral excerpts while providing continuous emotional ratings. Inter-subject correlation (ISC) analyses quantified voxelwise neural synchrony across the brain and within affective and reward-related regions of interest (ROIs). Continuous inter-subject representational similarity analysis (IS-RSA) tested whether pairwise neural synchrony varied with anhedonic depression symptoms, measured using the Mood and Anxiety Symptoms Questionnaire (MASQ-AD). Robust ISC was observed during music listening, particularly in bilateral auditory cortices (Heschls gyrus) and sensorimotor regions. Pairwise neural synchrony showed limited correspondence with similarity in continuous emotional subjective ratings, with significant associations primarily observed in auditory and somatosensory regions rather than classical affective regions. Anhedonia IS-RSA showed no reliable associations between MASQ-AD scores and pairwise neural synchrony across targeted affective and reward-related ROIs. These findings suggest that shared neural responses during music listening are strongest in perceptual and sensorimotor systems, whereas subjective emotional similarity and anhedonia-related variation showed limited correspondence with neural synchrony. This pattern highlights the value of continuous, naturalistic approaches for distinguishing shared stimulus-locked processing from more variable components of emotional experience.

neuroscience↗

bioRxiv2026

Brain dynamics of attentional, default-mode and limbic networks are disrupted at rest in Post-COVID-19 Syndrome

BackgroundPost-COVID-19 Syndrome (PCS) is characterised by persistent fatigue, cognitive impairments, and affective symptoms, yet its underlying neural mechanisms remain poorly understood. While static neuroimaging studies have identified resting-state connectivity abnormalities in PCS, such approaches fail to capture the brains dynamic functional organisation. This represents a missed opportunity to understand how alterations at the dynamic macroscale interactions give rise to the complex and fluctuating symptom profile of PCS. Cognitive and emotional processes rely on the brains capacity to flexibly reconfigure large-scale networks over time; disruptions in the exploration and transition between brain states may therefore play a central role in PCS pathophysiology. MethodsResting-state fMRI data were acquired from 20 individuals with PCS (mean age = 41.8 years, SD = 9.4) and 20 age- and sex-matched healthy controls (mean age = 40.6 years, SD = 8.1) using a multi-echo sequence. Following denoising with multi-echo independent component analysis, we applied Leading Eigenvector Dynamics Analysis (LEiDA) to identify recurrent patterns of whole-brain phase synchrony. The optimal number of dynamic brain states was determined using the Dunn index. For each state, we quantified probability of occurrence, lifetime, and transition probabilities, and mapped spatial topographies onto canonical functional networks. Group differences were assessed using ANCOVAs controlling for age, sex, and handedness. Exploratory associations with clinical symptoms, cognitive performance, and inflammatory markers were examined using both frequentist and Bayesian approaches. ResultsFive recurrent dynamic brain states were identified. Compared with controls, PCS participants showed reduced probability of occurrence and shorter lifetime of a visual/dorsal attention state, alongside increased probability of a limbic/default mode network (DMN) state. PCS was also characterised by reduced transitions between visual/dorsal attention and frontoparietal-DMN states, and increased transitions from somatomotor/visual states toward the limbic-DMN configuration. Exploratory analyses revealed that greater expression of the limbic-DMN state was negatively associated with global cognitive performance (MoCA) and positively associated with serum IL-1{beta} levels. ConclusionsPCS is associated with a reorganisation of intrinsic brain dynamics, marked by a shift from externally oriented attentional states toward limbic-DMN configurations. This imbalance may reflect reduced cognitive flexibility and increased sensitivity to interoceptive or affective signals. The observed links between dynamic brain-state expression, cognitive impairment, and peripheral inflammation support a systems-level mechanism through which immune signalling may influence neural function in PCS. Dynamic functional connectivity offers a sensitive framework for capturing these alterations and may inform future mechanistic models of post-viral dysfunction and therapeutic targeting. HighlightsO_LIPost-COVID-19 Syndrome (PCS) is linked to altered intrinsic brain dynamics at rest. C_LIO_LIPatients show reduced engagement of visual and attentional brain states. C_LIO_LIIncreased recruitment of limbic-DMN states suggests a shift toward more internally, emotionally charged focussed brain activity. C_LIO_LIBrain-state dynamics are putatively associated with global cognition and IL-1{beta}. C_LIO_LIReduced brain-state flexibility may underlie cognitive and emotional symptoms in PCS. C_LI

neuroscience↗

bioRxiv2023

Anhedonia severity mediates the relationship between attentional networks recruitment and emotional blunting during music listening

Recent studies have reported atypical emotional processing in individuals with greater levels of anhedonic depressive symptoms. However, the relationship between brain networks dynamics and moment-to-moment affective responses to naturalistic paradigms, as emotions are unfolding, remains unclear. In this study, we used the unique temporal characteristics of music to investigate behavioural and brain network dynamics as a function of anhedonic depressive symptoms severity in healthy adults during an emotionally provocative music listening task. Thirty-one neurotypical participants aged 18-30 years were required to continuously rate happy, neutral and sad pieces of music whilst undergoing MRI scanning. They were also asked to fill in questionnaires assessing their levels of anhedonic depressive symptoms. Using a novel fMRI analysis method called Leading Eigenvector Dynamics Analysis (LEiDA), we found an increased probability of occurrence of attentional networks and a blunted emotional response to both happy and sad pieces of music in participants with greater levels of anhedonic depressive symptoms. More specifically, anhedonic depressive symptoms mediated the relationship between attentional networks recruitment and emotional blunting. Furthermore, the elevated recruitment of attentional networks during emotional pieces of music carried over into subsequent neutral music. Future studies are needed to investigate whether these findings could be generalised to a clinical population (i.e., Major Depressive Disorder).

neuroscience↗