Biology subjects

Nummenmaa, L.

Publications and source records attributed to Nummenmaa, L..

At least 19 recordsLinked to original sources

bioRxiv2026

Neural Representations of Embodied Musical Emotions

Bodily sensations shape the emotional experience of music, yet the neural underpinnings of embodied musical emotions remain poorly understood. Here we investigated the correspondence between neural activity patterns and self-reported bodily sensations induced by emotional music. Participants (n=74) listened to emotionally engaging (aggressive, happy, sad, scary) music while their hemodynamic brain activity was measured with functional magnetic resonance imaging (fMRI). Music-induced bodily sensations were measured after imaging. Representational similarity analysis (RSA) was used to identify brain regions where the representational geometries of neural responses to music align with the topographical patterns of the corresponding bodily sensations, emotions, and musical features. Bodily sensations maps (BSMs) showed emotion-specific topographies. Univariate general linear model (GLM) analysis revealed increased neural activity within motor, somatosensory, interoceptive, limbic, and auditory brain regions during music listening, with little difference between the emotion categories. In contrast, RSA revealed significant correspondence between the representational geometries of neural activity patterns and emotion category-specific bodily sensations in motor, somatosensory, emotion-related and auditory brain regions. Multivariate pattern (MVP) classification analysis showed that activity in the auditory cortex accurately predicted the emotion categories. Our results indicate neural correspondence to bodily sensations in somatomotor and somatosensory brain regions, providing novel evidence for the neural basis of embodied music-induced emotions.

neuroscience↗

bioRxiv2026

Diurnal and seasonal regulation of brain mu-opioid and dopamine D2 receptor signalling in humans

Purpose: Rhythmic regulation of human neurotransmission systems, particularly the mu-opioid receptor (MOR) and dopamine D2 receptor (D2R) signaling, remains poorly understood. Although prior studies indicate possible diurnal fluctuations in D2R signaling, potential existence of diurnal rhythms in MOR signaling has yet to be investigated. Furthermore, whether and how seasonal factors may override or interact with diurnal rhythms in either system remains unexplored. Decoding these temporal dynamics and their possible links to behavioral traits, such as anxiety, may improve mood regulation models and inspire rhythm-tailored interventions. Methods: Based on a historical PET database of healthy humans scanned with [11C]carfentanil (n = 188) and [11C]raclopride (n = 184), we investigated the diurnal patterns of MOR and D2R availability in the brain, using time-of-day (TOD) of scanning as predictor. Furthermore, we examined whether the TOD differences in receptor availability were modulated by seasonal differences in the daylength (D2R and MOR) and trait-anxiety (MOR). Results: The data revealed increased MOR and decreased D2R availability in the afternoon compared to the morning scans. Interaction with the seasonal effect was, however, observed only for MOR availability, spanning brain areas including anterior cingulate, dorsomedial and dorsolateral prefrontal cortex, insula and striatum. Besides, the diurnal variation of MOR availability in these regions was also sensitive to trait-anxiety levels. Conclusions: The current results reveal the diurnal patterns in opioidergic and dopaminergic neurotransmission with an opposing trajectory. Furthermore, the data highlight a unique role of the MOR system, mediating both types of rhythmic regulations, as well as behavioral traits.

neuroscience↗

bioRxiv2026

Mapping the brain basis of appraisals and discrete emotions

The Component Process Model of Emotion conceptualizes any emotional episode (e.g., the discrete emotions of sadness, anger, fear, or interest) as being driven by the multiple appraisal components. However, both the specificity of the neural mechanisms underlying appraisal processes and the way these appraisal networks relate to the neural circuits underlying discrete emotions remain unclear. Here we investigated the neural correlates of appraisal processes and compared them with those of discrete emotions. Participants (n = 97) were scanned with functional magnetic resonance imaging (fMRI) while watching short movie clips with varying emotional contents. Intensity for 12 appraisals and 12 basic and epistemic emotions evoked by the movie clips were rated by independent participants (n = 444). The neural responses were modelled with convolved ratings of appraisals and discrete emotions. The results indicated that appraisals and discrete emotions are supported by a shared set of distributed brain regions that extend beyond typically reported emotion-related areas, encompassing perceptual, action-related, and higher-order cognitive systems. Activations were more consistent for and better explained by appraisals versus discrete emotions. Within this network, epistemic emotions elicited less consistent activations than basic emotions, particularly in limbic regions. Our results highlight the functional organization of appraisals and discrete emotions under dynamic and complex conditions and indicate that appraisal theories better explain neural responses than discrete emotion models.

neuroscience↗

bioRxiv2026

Endogenous Opioid System Modulates Neural Activation During Emotion Regulation

Emotion regulation is critical for adaptive functioning and mental health. Functional neuroimaging studies have identified distributed frontal, parietal, and limbic networks involved in emotion regulation, particularly during cognitive reappraisal. However, the neurochemical mechanisms underlying individual differences in emotion regulation remain poorly understood. The endogenous opioid system is a promising candidate because -opioid receptor systems acts as a stress buffer and modulates emotional responses to both rewarding and aversive stimuli We used positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) to examine whether baseline -opioid receptor (MOR) availability is associated with haemodynamic responses during emotion regulation through reappraisal. Participants underwent [11C]carfentanil PET imaging to quantify MOR availability and subsequently completed an fMRI task involving passive viewing of emotional images and cognitive reappraisal of their emotions during image viewing As expected, fMRI revealed engagement of the dorsolateral prefrontal cortex and inferior parietal lobule during cognitive reappraisal. Baseline MOR availability predicted blood oxygenation level-dependent (BOLD) responses in frontal, temporal, and parietal regions: individuals with higher MOR availability showed a larger difference between regulation and viewing trials in the temporal pole, angular gyrus, anterior insula, thalamus, and inferior frontal gyrus. These associations were driven primarily by stronger responses during passive viewing, although some regions also showed evidence of reduced responses during active reappraisal. These findings suggest that higher endogenous opioid tone is associated with stronger recruitment of distributed frontal, temporal, and parietal networks during emotional stimulus processing as well as attenuation of activity in some of these regions during cognitive reappraisal. Thus, while higher MOR availability is associated with enhanced neural responsiveness to emotional stimuli, these responses can nevertheless be effectively modulated through deliberate emotion regulation.

neuroscience↗

bioRxiv2026

Emotions and bodily sensations evoked by cardiac adenosine stress

Peripheral physiological processes contribute to emotions; however, the extent of the influence of internal signals on subjective emotional experiences remains a subject of debate. MethodsHere we investigated the bodily sensations induced by pharmacological stimulation with adenosine, a potent vasodilator that does not cross the blood-brain barrier, and how these sensations are translated into emotional experiences in 193 patients (94 males, 99 females; mean age 62.6 {+/-} 9.2 years) undergoing pharmacological cardiac stress testing as a part of their clinical assessment for suspected obstructive coronary artery disease. We characterized the subjective experiences induced by adenosine using topographical bodily maps and Likert-rating scales of 16 somatic sensations and 16 emotions. ResultsAdenosine induced strong and consistent bodily sensations related to dyspnea, chest pain, tachycardia, feelings of warmth, and tension in the body. The induced sensations were topographically distinct, with pain and pressure concentrated in the chest, warmth distributed across the upper body, and weakness localized to the torso. These sensations were accompanied by a significant increase in negative emotions, such as anxiety, fear, restlessness, panic, and a decrease in positive emotions of happiness, joy, and calmness. Peak heart rate response predicted the intensity of most bodily and emotional responses. Patients diagnosed with myocardial ischemia did not show heightened sensitivity to adenosine-induced bodily sensations compared to non-ischemic patients, despite exhibiting a blunted tachycardiac reflex. ConclusionThese findings show that peripheral physiological activation alone is sufficient to drive subjective emotional experiences, providing causal evidence for the embodied nature of emotions.

physiology↗

bioRxiv2025

Attentional reconfiguration during acute and sustained fear

BACKGROUNDFear is a fundamental survival mechanism that both enhances the chances of survival by rapid detection and adaptive responses to potential threat and by optimizing sensory input and cognitive processing. Here we used naturalistic design with eye tracking to map the spatiotemporal dynamics of attention and arousal during fearful events with slow and fast temporal dynamics. METHODS21 participants watched a full-length horror movie while their eye-movements were recoded with eye tracker. Moment-to-moment intensity of sustained fear as well as the onsets of the jump scares (acute fear) were annotated and used to predict gaze parameters (fixation duration & counts, blink frequency, saccade amplitude, pupil size and intersubject synchronization of gaze position). RESULTSAcute fear events led to shortening of fixation duration, suppression of blinking, as well as increase of fixation count, saccade amplitude, and pupil size. Sustained fear was in turn associated with increased pupil size and decrease in blinking and saccade amplitude. These effects remained significant when controlling for luminosity. CONCLUSIONSDuring natural vision both acute and sustained fear cause rapid reconfiguration, state dependent and individual changes in visual attention prioritizing that is accompanied by increased affective arousal.

neuroscience↗

bioRxiv2025

Autistic traits modulate neural responses to social signals during natural vision

Impairments in social perception, a hallmark of autism spectrum disorder (ASD), are also evident at subclinical levels in the general population. However, it remains unclear how such variation in autistic traits modulate neural processing of different types of social information. Here, we investigated whether autistic traits in neurotypical individuals are associated with neural responses to a broad array of social perceptual features during viewing naturalistic stimuli using functional magnetic resonance imaging (fMRI). We also tested the generalizability of these effects across two experiments. Ninety-seven participants completed the Autism Spectrum Quotient (AQ) and watched a set of 96 movie clips and a full movie during an fMRI scan. Intensity of 126 social features in the movie stimuli was continuously annotated by independent observers, and 44 most reliably rated features were used to model neural responses. We examined how consistently the responses to each social feature were dependent on the participants AQ scores. Replicable AQ-dependent neural responses to social features were found in both datasets. The temporal cortex and especially the superior temporal gyrus (STG), served as a central "hub" where autistic traits consistently modulated responses to social features across datasets. Different AQ subscales also revealed distinct association patterns in other brain regions. These findings indicate that autism-related traits broadly influence neural processing of naturalistic social signals, providing insight into how characteristics of autistic symptoms relate to socioemotional processing.

neuroscience↗

bioRxiv2025

Striatal dopamine synthesis capacity in Parkinson's disease: Effects of age, sex, and body mass index in a large fluorodopa PET cohort

BACKGROUNDIn Parkinsons disease (PD), the degeneration of nigrostriatal dopaminergic neurons leads to motor symptoms. Positron emission tomography (PET) using radioligand [18F]fluorodopa detects reduced striatal dopamine synthesis capacity in PD patients. Demographic factors such as sex and BMI are also associated with dopamine synthesis capacity. The combined contribution of demographic and clinical effects however remains elusive. It also remains unresolved how the dopamine synthesis capacity is correlated between striatal subregions and how the dopamine synthesis capacity and dopamine receptor function across striatal regions are associated with each other in PD patients and healthy controls. MATERIAL, AIMS, AND METHODSFor this retrospective register-based study, we used baseline [18F]fluorodopa PET data acquired at the Turku PET Centre between the years 1988-2016 with three different scanners (Ecat 931, GE Advance, HRRT). The data included scans of 350 adult human subjects, including 132 healthy controls (65 males and 67 females), and 218 PD patients (134 males and 84 females). The primary aim was to simultaneously investigate the effects of PD, age, sex and BMI on regional dopamine synthesis capacity (influx rate constant Kiref quantified with Patlak) using Bayesian linear regression. Secondary aims were to assess interregional correlations of dopamine synthesis capacity, and the association between regional presynaptic dopamine synthesis and postsynaptic dopamine type 2 receptor (D2R) availability in subjects who also had a proximal [11C]raclopride PET scan. RESULTSWe found modest support for age-dependent decline in dopamine synthesis capacity, increased capacity for higher BMIs, and for higher capacity in females versus males. These effects were smaller than the effect of PD status. Dopamine synthesis capacity across regions was correlated in both patients and controls. Support for positive correlation between the synthesis capacity and the D2R was observed in caudate nucleus. CONCLUSIONSPD and demographic effects are independently associated with the striatal dopamine synthesis capacity. The capacity is reduced by PD, decreased through age (particularly after the age of around 50), higher in females versus males, and weakly increased in higher BMIs. Synthesis capacity is correlated between the striatal and thalamic regions in both PD patients and controls. The dopamine synthesis capacity was positively correlated with the D2R availability in caudate. Scanner affects the estimates of dopamine synthesis capacity measured with [18F]fluorodopa PET, and it is preferrable to adjust for such variation in the data.

neuroscience↗

bioRxiv2025

GPT-4 accurately predicts human emotions and their neural correlates

Emotions are evoked by both internal and external events related to survival challenges. Recent advances in multimodal large language models ((M)LLMs), such as GPT-4, enable them to accurately analyze and describe complex visual scenes, raising the question whether LLMs can also predict human emotional experiences evoked by similar scenes. Here we asked GPT-4 and humans (N = 519) to provide self-reports of 48 unipolar emotions and aFective dimensions for emotionally evocative videos and images. We evaluated GPT-4s emotion ratings using three natural socio-emotional stimulus datasets: two video datasets (234 and 120 videos) and one image dataset (300 images). We found that GPT-4 can predict emotions of human observers with high accuracy. The multivariate emotion structure (correlation matrices of emotions ratings) converged between GPT-4 and humans and across datasets indicating that GPT-4 ratings for diFerent emotions follow similar structural representations as the human evaluations. Finally, we modeled the brains hemodynamic responses for emotions elicited by videos or images in two fMRI datasets (N = 97) with GPT-4 or human-based emotional evaluations to highlight the usefulness of GPT-4 in neuroscientific research. The results showed that the brains emotion circuits can be mapped with high accuracy using GPT-4 emotion ratings as the stimulation model. In conclusion, GPT-4 can predict human emotion ratings to the extent that GPT-4 ratings can also model the associated neural responses. Our results indicate that LLMs provide novel and scalable tools that have broad potential in emotion research, cognitive and aFective neuroscience, and that it can also have practical applications.

neuroscience↗

bioRxiv2025

Inter-individual variability of neurotransmitter receptor and transporter density in the human brain

Neurotransmitter receptors guide the propagation of signals between brain regions. Mapping receptor distributions in the brain is therefore necessary for understanding how neurotransmitter systems mediate the link between brain structure and function. Normative receptor density can be estimated using group averages from Positron Emission Tomography (PET) imaging. However, the generalizability and reliability of group-average receptor maps depends on the inter-individual variability of receptor density, which is currently unknown. Here we collect group standard deviation brain maps of PET-estimated protein abundance for 12 different neurotransmitter receptors and transporters across 7 neurotransmitter systems, including dopamine, serotonin, acetylcholine, glutamate, GABA, cannabinoid, and opioid. We illustrate how cortical and subcortical inter-individual variability of receptor and transporter density varies across brain regions and across neurotransmitter systems. We complement inter-individual variability with inter-regional variability, and show that receptors that vary more across brain regions than across individuals also demonstrate greater out-of-sample spatial consistency. Altogether, this work quantifies how receptor systems vary in healthy individuals, and provides a means of assessing the generalizability of PET-derived receptor density quantification.

neuroscience↗

bioRxiv2025

Physical exercise and brain network dynamics: reduction of frontoparietal-striatal connectivity following 1 hour of aerobic cycling

Physical exercise is beneficial for metabolic health and cognitive performance. In addition, exercise can be highly pleasurable and and serves as an effective stress reliever. Extant studies have highlighted frontal, parietal, and subcortical brain changes following acute bouts of exercise. However, slower, slightly delayed brain correlates after exercise at the network level have not been studied. Therefore, this studys objective was to investigate the changes in dynamic functional connectivity after 60 minutes of exercise in healthy males. Here we measured a 6-minute resting state fMRI in 24 young males at baseline and after a 60-minute cycling exercise challenge. Apart from routine preprocessing, the data were denoised with FSL-FIX and modeled with i) leading eigenvector dynamics analysis (LEiDA) to probe whole brain network dynamics and ii) with group independent component analysis (ICA) and dual regression to quantify static brain connectivity. The within subject statistical tests compared baseline to post-exercise conditions. We found that a striato-fronto-parietal network is destabilized after exercise, as indicated by a lower probability of occurrence in dynamic analysis through LEiDA. The brain areas in the network include the bilateral caudate, putamen and pallidum as well as middle orbitofrontal, frontal operculum, frontal trigonum and inferior parietal cortices. No differences between baseline and post exercise conditions were found in the dual regression of the group ICA components. We conclude that 60 minutes of cycling causes a prolonged effect in brain network dynamics, reducing synchronization between the striatum and frontoparietal networks with respect to baseline. This provides insights into the network-level neural correlates of aerobic exercise, which may be directly linked with the stress relieving effects of physical exercise.

neuroscience↗

bioRxiv2025

CEREBRAL GLUCOSE UTILISATION DURING MUSICAL EMOTIONS: A MULTIMODAL FUNCTIONAL PET/MRI STUDY.

Functional magnetic resonance imaging (fMRI) studies have demonstrated music-induced activation of the blood-oxygen-level-dependent (BOLD) signal across brain networks associated with auditory perception, motor control, and emotion. However, BOLD-fMRI reflects vascular responses that may not fully capture underlying neural activity. Here, we used simultaneous [18F]fluorodeoxyglucose (FDG) functional positron emission tomography (fPET) and fMRI to examine glucose metabolism closely linked to neural activity, alongside hemodynamic responses during pleasurable music listening. Thirty-five female participants listened to self-selected pleasurable music and control stimuli while undergoing 90-minute PET-MRI scans. fPET revealed music-evoked increase in glucose consumption in auditory and motor cortices, as well as reward-related regions, including the nucleus accumbens (NAcc), caudate, insula, and orbitofrontal cortex. The fPET and fMRI results showed substantial overlap though some discrepancies were also observed. Notably, the NAcc exhibited increased glucose consumption in fPET but showed no activation in fMRI. Conversely, deactivation of the default mode network during music processing was only observed with fMRI. These results highlight the complementary nature of neurometabolic and neurovascular processes and offer novel insights into their dynamics during the processing of aesthetic rewards.

neuroscience↗

bioRxiv2025

TURBO: Automated Total-body PET Image Processing and Kinetic Modeling Toolbox

Long axial field of view (LAFOV) PET imaging requires a high level of automation and standardization, as the large number of target tissues increases the manual workload significantly. We introduce an automated analysis pipeline (TurBO, Turku total-BOdy) for preprocessing and kinetic modelling of LAFOV [15O]H2O and [18F]FDG PET data, enabling efficient and reproducible analysis of tissue perfusion and metabolism at regional and voxel-levels. The approach employs automated processing including co-registration, motion correction, automated CT segmentation for region of interest (ROI) delineation, image-derived input determination, and region-specific kinetic modelling of PET data. MethodsWe validated the analysis pipeline using Biograph Vision Quadra (Siemens Healthineers) LAFOV PET/CT scans from 21 subjects scanned with [15O]H2O and 16 subjects scanned with [18F]FDG using six segmented CT-based ROIs (cortical brain gray matter, left iliopsoas muscle, right kidney cortex and medulla, pancreas, spleen and liver) representing different levels of blood flow and glucose metabolism. ResultsModel fits showed good quality with consistent parameter estimates at both regional and voxel-levels (R{superscript 2} > 0.83 for [15O]H2O, R{superscript 2} > 0.99 for [18F]FDG). Estimates from manual and automated input functions were in concordance (R{superscript 2} > 0.74 for [15O]H2O, and R{superscript 2} > 0.78 for [18F]FDG) with minimal bias (<4% for [15O]H2O and <10% for [18F]FDG). Manually and automatically (CT-based) extracted ROI level data showed strong agreement (R{superscript 2} > 0.82 for [15O]H2O and R{superscript 2} > 0.83 for [18F]FDG), while motion correction had little impact on parameter estimates (R{superscript 2} > 0.71 for [15O]H2O and R{superscript 2} > 0.78 for [18F]FDG) compared with uncorrected data. ConclusionOur automated analysis pipeline provides reliable and reproducible parameter estimates across different regions, with an approximate processing time of 1-1.5 h per subject. This pipeline completely automates LAFOV PET analysis, reducing manual effort and enabling reproducible studies of inter-organ blood flow and metabolism, including brain-body interactions.

neuroscience↗

bioRxiv2025

Four-dimensional neural space for moral inference

Intuitive moral inference enables us to evaluate moral situations and judge their rightness or wrongness. Although Moral Foundations Theory provides a framework for understanding moral inference, its underlying neural basis remains unclear. To capture spontaneous neural activity during moral inference, participants were instructed to watch a film rich in moral content without making explicit judgments while undergoing fMRI scanning. Independent participants evaluated the moment-to-moment presence of twenty moral dimensions in the film. Correlation and consensus cluster analyses revealed four independent main moral dimensions: virtue, vice, hierarchy, and rebellion. While each dimension exhibited unique neural activation patterns, the temporoparietal junction and inferior parietal lobe were activated across all types of moral inference. These findings establish the low-dimensional nature for the neural basis of intuitive moral inference in everyday settings.

neuroscience↗

bioRxiv2025

Shared brain basis of aggression in clinical, forensic, and healthy samples: A meta-analysis

BackgroundAggression, violence, and antisocial behaviour constitute a large-scale societal problem. Aggression is common in incarcerated offenders and psychiatric conditions, but also healthy and noninstitutionalized populations vary in violent and aggressive behaviour. The brain basis of aggression has been studied extensively in the past, but the similarities between criminal, pathological and everyday aggression in the brain remain elusive. MethodsWe conducted an activation likelihood estimation (ALE) meta-analysis of 406 neuroimaging studies with 28 968 subjects using structural magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI), positron emission tomography (PET) and single photon emission tomography (SPECT). The included studies had either i) measured haemodynamic responses during aggression-related functional tasks, ii) compared the brain structure, molecular organization, or function between aggressive forensic and psychiatric populations and control groups, or iii) addressed the effects of trait aggression on brain structure or function. ResultsAggression was consistently associated with altered function and structure in the amygdala, hippocampus, basal ganglia, anterior cingulate cortex, and the dorsolateral and orbitofrontal cortices. Functional coactivation analysis suggested that these regions are most consistently associated with emotional and reward function as well as their regulation. The results were comparable in healthy subjects as well as forensic and psychiatric populations. ConclusionsAggression is linked with alterations in multiple neurocognitive systems forming a common network for aggressiveness. Particularly the neural systems implicated in reward, emotions and regulation were commonly associated with aggression. The established network is involved in the whole continuum of aggression from benign variations in healthy volunteers to forensic subjects and violent clinical populations, suggesting a common aggression network whose severe perturbations may be linked with criminal behaviour or pathological aggression.

neuroscience↗

bioRxiv2025

Exposure to bullying engages social distress circuits in the adolescent and adult brain

Despite advances in understanding the psychological and social consequences of peer victimization, the immediate effects of bullying on the central nervous system remain elusive. Here we mapped the neural responses to simulated bullying in adolescents and adults and tested whether these responses are associated with real-life victimization experiences. Fifty-one adolescents aged 11-14 years, and 47 adults underwent a functional MRI (fMRI) while watching first-person videos of bullying (victimization) in the school environment, as well as neutral and positive social interactions in a similar setting. Exposure to bullying versus positive social interaction engaged the socio-emotional and threat response systems, as well as regions related to social cognition, sensory and interoceptive processing, and motor control. These responses were consistent across adolescents and adults and dependent on the current and past victimization experiences of the participants. This large-scale activation of neural systems subserving socioemotional, somatosensory, and interoceptive processing highlights how peer victimization evokes a severe stress and alarm state in the central nervous system.

neuroscience↗

bioRxiv2025

Reduced inter-subject functional connectivity during movies in autism: Replicability across cross-national fMRI datasets

BackgroundAutism is a neurodevelopmental disorder characterized by repetitive behaviors and difficulties in social communication and interaction. Previous research has shown that these symptoms are linked to idiosyncratic behavioral and brain activity patterns while viewing natural social events in movies. This study aimed to investigate the replicability of brain activity idiosyncrasy in autistic individuals by comparing their inter-subject functional connectivity (ISFC) with that of neurotypical individuals. MethodsWe tested for ISFC differences between autistic and neurotypical groups using functional magnetic resonance imaging (fMRI) data from two independent datasets from Germany (Nneurotypical = 25, 7 Males, 18 Females; Nautism = 22, 12 Males, 10 Females) and Finland (Nneurotypical = 19, Nautism = 18; All males). Participants watched short movie stimuli, and pairwise ISFCs were computed across 273 brain regions. Group differences were evaluated using subject-wise permutation tests for each dataset. ResultsIn both datasets, the autistic group showed lower ISFCs compared to the neurotypical group, specifically between visual regions (e.g., occipital gyrus, cuneus) and parietal regions (e.g., superior and inferior parietal lobules), as well as between visual regions and frontal regions (e.g., inferior frontal gyrus, precentral gyrus). ISFC was higher in the Finnish autistic group in temporal regions associated with sound and speech processing. ConclusionsThe study confirmed the replicability of reduced ISFCs in autistic individuals during naturalistic movie-watching, especially between visual and parietal/frontal brain regions. These findings reinforce the utility of ISFC and naturalistic movie-watching paradigm in studying neural connectivity alterations in autism.

neuroscience↗

bioRxiv2024

Modelling human social vision with cinematic stimuli

Sociability is central for humans. Visual information ranging from low-level physical features (e.g. luminance) to semantic information (e.g. face recognition) and high-level social inference (e.g. emotional valence of social interactions) is constantly sampled for navigating the social world. Here we utilize large-scale eye tracking during natural vision for mapping how different levels of visual information guide the perception of social scenes. In three experiments, participants (N = 166) watched full-length films and short movie clips with varying social content (total duration: 193 minutes) during eye tracking. To model the association between the perceptual features and spatiotemporal eye movement parameters (gaze position, gaze synchronization, pupil size and blinking), we extracted 39 stimulus features from the movies including low-level audiovisual features (e.g. luminance, motion), presence and location of mid-level semantic categories (e.g. faces, objects) and high-level social information (e.g. body movements, pleasantness). Pupil size was modulated by luminance, scene cuts and emotional arousal while gaze position was most accurately predicted by a combination of the presence of human faces, local motion and entropy. Faces and eyes were prioritized over other semantic categories and blinking rate decreased during periods of attentional engagement. Altogether the results show that human social vision is primarily guided by low-level physical features and mid-level semantic categories, while high-level social features such as emotional arousal primarily modulate pupillary responses.

neuroscience↗