Biology subjects

Lee Masson, H.

Publications and source records attributed to Lee Masson, H..

8 recordsLinked to original sources

bioRxiv2023

Multidimensional neural representations of social features during movie viewing

The social world is dynamic and contextually embedded. Yet, most studies utilize simple stimuli that do not capture the complexity of everyday social episodes. To address this, we implemented a movie viewing paradigm and investigated how the everyday social episodes are processed in the brain. Participants watched one of two movies during an MRI scan. Neural patterns from brain regions involved in social perception, mentalization, action observation, and sensory processing were extracted. Representational similarity analysis results revealed that several labeled social features (including social interaction, mentalization, the actions of others, characters talking about themselves, talking about others, and talking about objects) were represented in superior temporal gyrus (STG) and middle temporal gyrus (MTG). The mentalization feature was also represented throughout the theory of mind network, and characters talking about others engaged the temporoparietal junction (TPJ), suggesting that listeners may spontaneously infer the mental state of those being talked about. In contrast, we did not observe the action representations in frontoparietal regions of the action observation network. The current findings indicate that STG and MTG serve as central hubs for social processing, and that listening to characters talk about others elicits spontaneous mental state inference in TPJ during natural movie viewing.

neuroscience↗

bioRxiv2023

Rapid processing of observed touch through social perceptual brain regions: an EEG-fMRI fusion study

Seeing social touch triggers a strong social-affective response that involves multiple brain networks, including visual, social perceptual, and somatosensory systems. Previous studies have identified the specific functional role of each system, but little is known about the speed and directionality of the information flow. Is this information extracted via the social perceptual system or from simulation from somatosensory cortex? To address this, we examined the spatiotemporal neural processing of observed touch. Twenty participants watched 500 ms video clips showing social and non-social touch during EEG recording. Visual and social-affective features were rapidly extracted in the brain, beginning at 90 and 150 ms after video onset, respectively. Combining the EEG data with fMRI data from our prior study with the same stimuli reveals that neural information first arises in early visual cortex (EVC), then in the temporoparietal junction and posterior superior temporal sulcus (TPJ/pSTS), and finally in the somatosensory cortex. EVC and TPJ/pSTS uniquely explain EEG neural patterns, while somatosensory cortex does not contribute to EEG patterns alone, suggesting that social-affective information may flow from TPJ/pSTS to somatosensory cortex. Together, these findings show that social touch is processed quickly, within the timeframe of feedforward visual processes, and that the social-affective meaning of touch is first extracted by a social perceptual pathway. Such rapid processing of social touch may be vital to its effective use during social interaction. Significance StatementSeeing physical contact between people evokes a strong social-emotional response. Previous research has identified the brain systems responsible for this response, but little is known about how quickly and in what direction the information flows. We demonstrated that the brain processes the social-emotional meaning of observed touch quickly, starting as early as 150 milliseconds after the stimulus onset. By combining EEG data with fMRI data, we show for the first time that the social-affective meaning of touch is first extracted by a social perceptual pathway and followed by the later involvement of somatosensory simulation. This rapid processing of touch through the social perceptual route may play a pivotal role in effective usage of touch in social communication and interaction.

neuroscience↗

bioRxiv2022

A shared neural code for social interaction encoding and memory in the human superior temporal sulcus

Recognizing and remembering social information is a crucial cognitive skill. Neural patterns in the superior temporal sulcus (STS) support our ability to perceive others social interactions. However, despite the prominence of social interactions in memory, the neural basis of retrieving social interactions is still unknown. To fill this gap, we investigated the brain mechanisms underlying memory of others social interactions during free spoken recall of a naturalistic movie. By applying machine learning-based fMRI encoding analyses to densely labeled movie and recall data we found that STS activity patterns evoked by viewing social interactions predicted neural responses to social interaction memories. This finding suggests that the STS contains high-level conceptual, representations of social interactions, and its reactivation underlies our ability to remember others interactions.

neuroscience↗

bioRxiv2021

Functional selectivity for naturalistic social interaction perception in the human superior temporal sulcus

Recognizing others social interactions is a crucial human ability. Using simple stimuli, previous studies have shown that social interactions are selectively processed in the superior temporal sulcus (STS), but prior work with movies has suggested that social interactions are processed in the medial prefrontal cortex (mPFC), part of the theory of mind network. It remains unknown to what extent social interaction selectivity is observed in real world stimuli when controlling for other covarying perceptual and social information, such as faces, voices, and theory of mind. The current study utilizes a functional magnetic resonance imaging (fMRI) movie paradigm and advanced machine learning methods to uncover the brain mechanisms uniquely underlying naturalistic social interaction perception. We analyzed two publicly available fMRI datasets, collected while both male and female human participants (n = 17 and 18) watched two different commercial movies in the MRI scanner. By performing voxel-wise encoding and variance partitioning analyses, we found that broad social-affective features predict neural responses in social brain regions, including the STS and mPFC. However, only the STS showed robust and unique selectivity specifically to social interactions, independent from other covarying features. This selectivity was observed across two separate fMRI datasets. These findings suggest that naturalistic social interaction perception recruits dedicated neural circuity in the STS, separate from the theory of mind network, and is a critical dimension of human social understanding. Significance StatementSocial interaction perception guides our daily behavior, yet it is unknown how our brain processes real-world social interaction scenes. Here, we demonstrate that social brain areas, including the superior temporal sulcus (STS) and medial prefrontal cortex (mPFC), are sensitive to broad social-affective information in naturalistic movies, replicating prior results with controlled paradigms. We show for the first time however, that the STS, but not mPFC, selectively processes social interactions in natural movies, independent of other co-occurring perceptual and social features, including motion, presence of faces, speech, and mentalizing about others. Our results suggest that social interaction perception is a crucial dimension of social understanding represented in the human brain.

neuroscience↗

bioRxiv2019

Social touch observation in adults with autism: intact neural representations of affective meaning but lack of embodied resonance

Humans can easily grasp the affective meaning of touch when observing social interactions. Several neural systems support this ability, including theory of mind (ToM) and somatosensory resonance systems, but it is unclear how these systems are affected in autism spectrum disorder (ASD). Individuals with ASD are characterized by impairments in social interaction and the use of (non)verbal communication such as social and reciprocal touch. The present study applies an ecologically valid stimulus set and multivoxel pattern fMRI neuroimaging to pinpoint atypicalities in the neural circuitry underlying socio-affective touch observation in adults with ASD as compared to matched neurotypical controls. The MVPA results reveal that the affective meaning of touch is well represented in the temporoparietal junction, a core ToM mentalizing area, in both groups. Conversely, only the neurotypical group hosts affective touch representations in the somatosensory cortex, not the ASD group, yielding a significant group difference. Lastly, individuals with a more positive attitude towards receiving, witnessing, and providing social touch and with a higher score on social responsivity, show more differentiated representations of the affective meaning of touch in these somatosensory areas. Together, our findings imply that individuals with ASD are able to cognitively represent the affective meaning of touch, but they lack the spontaneous embodied somatosensory resonance when observing social touch communications. Individual differences in this diminished resonance appear to be related to social touch avoidance and quantitative autism traits.\n\nSignificance StatementAutism is characterized by socio-communicative impairments, including abnormal processing of interpersonal touch. Little is known about the neural basis of atypicalities in social touch processing in autism. Here, adults with and without autism watched video clips displaying social touch interactions and judged the affective valence of the touch. Subsequently, they underwent functional magnetic resonance imaging while watching the same videos. Brain activity patterns demonstrate that adults with autism show intact cognitive understanding (i.e. \"knowing\") of observed socio-affective touch experiences but lack of embodied emotional resonance (i.e. \"feeling\"). This lack of emotional resonance is linked to social touch avoidance and quantitative autism traits. These findings highlight that the depth of experiencing the state of others is shallower in people with autism.

neuroscience↗

bioRxiv2018

The (dis)similarities between neural networks based upon functional connectivity, representational similarity, and univariate analyses

In fMRI research, univariate analysis (UNIVAR), representational similarity analysis (RSA, following multi-voxel pattern analysis (MVPA)), and functional connectivity analysis (FCA) are the most commonly used methods by cognitive neuroscientists investigating the functional organization of the human brain. Despite their popularity, few studies have examined the relationship between the network structures as identified through these different methods. Thus, the current study aims to evaluate the similarities between neural networks derived from UNIVAR, RSA, and FCA, and to clarify how these methods relate to each other. To achieve this goal, we analyzed the data of a previously published study with the three methods and compared the results by performing (partial) correlation and multiple regression analysis. Our findings reveal that neural networks resulting from UNIVAR, RSA, and FCA methods are highly similar to each other even after ruling out the effect of anatomical proximity between the network nodes. Nevertheless, the neural network from each method shows idiosyncratic structure that cannot be explained by any of the other methods. Thus, we conclude that the UNIVAR, RSA, and FCA methods provide similar but not identical information on how brain regions are organized in functional networks.

neuroscience↗

bioRxiv2017

Neural Representations Behind Social Norm Inferences In Humans

Humans are highly skilled in social reasoning, e.g., inferring thoughts of others. This mentalizing ability systematically recruits brain regions such as Temporo-Parietal Junction (TPJ), Precuneus (PC) and medial Prefrontal Cortex (mPFC). Further, posterior mPFC is associated with allocentric mentalizing and conflict monitoring while anterior mPFC is associated with self-related mentalizing. Here we extend this work to how we reason not just about what one person thinks but about the abstract shared social norm. We apply functional magnetic resonance imaging to investigate neural representations while participants judge the social congruency between emotional auditory in relation to visual scenes according to how most people would perceive it. Behaviorally, judging according to a social norm increased the similarity of response patterns among participants. Multivoxel pattern analysis revealed that social congruency information was not represented in visual and auditory areas, but was clear in most parts of the mentalizing network: TPJ, PC and posterior (but not anterior) mPFC. Furthermore, interindividual variability in anterior mPFC representations was inversely related to the behavioral ability to adjust to the social norm. Our results suggest that social norm inferencing is associated with a distributed and partially individually specific representation of social congruency in the mentalizing network.

neuroscience↗

bioRxiv2017

Socio-affective touch expression database

Socio-affective touch communication conveys a vast amount of information about emotions and intentions in social contexts. In spite of the complexity of the socio-affective touch expressions we use daily, previous studies addressed only a few aspects of social touch mainly focusing on hedonics, such as stroking, leaving a wide range of social touch behaviour unexplored. To overcome this limit, we present the Socio-Affective Touch Expression Database (SATED), which includes a large range of dynamic interpersonal socio-affective touch events varying in valence and arousal. The original database contained 26 different social touch expressions each performed by three actor pairs. To validate each touch expression, we conducted two behavioural experiments investigating perceived naturalness and affective values. Based on the rated naturalness, 13 socio-affective touch expressions along with 12 corresponding non-social touch events were selected as a complete set, achieving 75 video clips in total. Moreover, we quantified motion energy for each touch expression to investigate its intrinsic correlations with perceived affective values and its similarity among actor-and action-pairs. As a result, the touch expression database is not only systematically defined and well-controlled, but also spontaneous and natural, while eliciting clear affective responses. This database will allow a fine-grained investigation of complex interpersonal socio-affective touch in the realm of social psychology and neuroscience along with potential application areas in affective computing and neighbouring fields.

neuroscience↗