Biology subjects

Sams, M.

Publications and source records attributed to Sams, M..

10 recordsLinked to original sources

bioRxiv2023

Psychopathic traits predict neural responses to emotional movies in the general population

Psychopathic personality traits such as callousness, manipulativeness, and lack of empathy are continuously distributed in non-institutionalized populations. Here, we show that brain responses to emotional movies in healthy females vary as a function of primary (PP) and secondary psychopathy (SP) traits. Healthy female volunteers (n=50) with variable scorings in Levenson Self-Report Psychopathy Scale watched a set of emotional movie clips (n=39) during functional magnetic resonance imaging of brain activity. We found that participants low on primary and secondary psychopathy traits showed higher cortical and subcortical activity when watching emotional movies, what possibly indicates the somatosensory simulation and empathizing with the emotions of movie characters. On the other hand, the individuals with high primary and secondary psychopathy traits presented a lack of vicarious engagement during watching movies and they manifested brainstem-based heightened response towards thread-related stimuli, which could indicate potent autonomic reactivity. Overall, our results indicate that variability in psychopathic traits in the general population is manifested as differential neural responses to emotional signals, and confirm previous findings of there being separate PP and SP personality characteristics due to the dissociable brain activity patterns while viewing emotional movies.

neuroscience↗

bioRxiv2023

Cerebral Topographies of Perceived and Felt Emotions

Emotions modulate behavioral priorities based on exteroceptive and interoceptive inputs, and the related central and peripheral changes may often be experienced subjectively. Yet, it remains unresolved whether the perceptual and subjectively felt components of the emotion processes rely on shared brain mechanisms. We applied functional magnetic resonance imaging, a rich set of emotional movies, and high-dimensional, continuous ratings of perceived and felt emotions depicted in the same movies to investigate their cerebral organization. Eight main dimensions of emotions evoked during natural movie scene perception were represented in the brain across numerous spatial scales and patterns. Perceived and felt emotions generalized both between individuals and between different samples of stimuli depicting the same emotions. The neural affective space demonstrated an anatomical gradient from responses independent of specific emotions in polysensory areas and default mode regions to more localized and emotion-specific discrete processing in subcortical regions. Differences in neural activations during felt and perceived emotions suggest that temporoparietal areas and precuneus have a key role in computing the affective value of the sensory input. This affective value is then transformed into the subjective emotional experience in the anterior prefrontal cortices, cerebellum, and thalamus. Altogether these data reveal the similarities and differences of domain-general and emotion-specific affect networks in the brain during a wide range of perceived and felt emotions.

neuroscience↗

bioRxiv2022

Decoding brain basis of laughter and crying in natural scenes.

Laughter and crying are universal signals of prosociality and distress, respectively. Here we investigated the functional brain basis of perceiving laughter and crying using naturalistic functional magnetic resonance imaging (fMRI) approach. We measured haemodynamic brain activity evoked by laughter and crying in three experiments with 100 subjects in each. The subjects i) viewed a 20-minute medley of short video clips, and ii) 30 minutes of a full-length feature film, and iii) listened to 15 minutes of a radio play that all contained bursts of laughter and crying. Intensity of laughing and crying in the videos and radio play was annotated by independent observes, and the resulting time series were used to predict hemodynamic activity to laughter and crying episodes. Multivariate pattern analysis (MVPA) was used to test for regional selectivity in laughter and crying evoked activations. Laughter induced widespread activity in ventral visual cortex and superior and middle temporal and motor cortices. Crying activated thalamus, cingulate cortex along the anterior-posterior axis, insula and orbitofrontal cortex. Both laughter and crying could be decoded accurately (66-77% depending on the experiment) from the BOLD signal, and the voxels contributing most significantly to classification were in superior temporal cortex. These results suggest that perceiving laughter and crying engage distinct neural networks, whose activity suppresses each other to manage appropriate behavioral responses to others bonding and distress signals. Significance statementLaughter and crying are universal signals of prosociality and distress, respectively. They occur in complex, dynamic social settings with variable and dynamically evolving time courses. Here we used functional magnetic resonance imaging experiments and statistical pattern recognition for disentangling the neural systems that encode laughter and crying signals from dynamic and highly naturalistic scenes. These results show that separable neural circuits are engaged in processing distinct types of social attachment cues, and that pattern recognition during dynamic scene perception allows reliable separation of laughter and crying evoked activation patterns. Coordinated activity of these networks allows managing appropriate behavioral responses to others bonding and distress signals.

neuroscience↗

bioRxiv2020

Processing of a spoken narrative in the human brain is shaped by family cultural background

Using neuroimaging, we studied influence of family cultural background on processing of an audiobook in human brain. The audiobook depicted life of two young Finnish men, one with the Finnish and the other with the Russian family background. Shared family cultural background enhanced similarity of narrative processing in the brain at prelexical, word, sentence, and narrative levels. Similarity was also enhanced in brain areas supporting imagery. The cultural background was further reflected as semantic differences in word lists by which the subjects described what had been on their minds when they heard the audiobook during neuroimaging. Strength of social identity shaped word, sentence, and narrative level processing in the brain. These effects might enhance mutual understanding between persons who share family cultural background and social identity and, conversely, deteriorate between-group mutual understanding in modern multicultural societies wherein native speakers of a language may assume highly similar understanding.

neuroscience↗

bioRxiv2020

Classification of emotions based on functional connectivity patterns of the human brain

Neurophysiological and psychological models posit that emotions depend on connections across wide-spread corticolimbic circuits. While previous studies using pattern recognition on neuroimaging data have shown differences between various discrete emotions in brain activity patterns, less is known about the differences in functional connectivity. Thus, we employed multivariate pattern analysis on functional magnetic resonance imaging data (i) to develop a pipeline for applying pattern recognition in functional connectivity data, and (ii) to test whether connectivity signatures differ across emotions. Six emotions (anger, fear, disgust, happiness, sadness, and surprise) and a neutral state were induced in 16 participants using one-minute-long emotional narratives with natural prosody while brain activity was measured with functional magnetic resonance imaging (fMRI). We computed emotion-wise connectivity matrices both for whole-brain connections and for 10 previously defined functionally connected brain subnetworks, and trained an across-participant classifier to categorize the emotional states based on whole-brain data and for each subnetwork separately. The whole-brain classifier performed above chance level with all emotions except sadness, suggesting that different emotions are characterized by differences in large-scale connectivity patterns. When focusing on the connectivity within the 10 subnetworks, classification was successful within the default mode system and for all emotions. We conclude that functional connectivity patterns consistently differ across different emotions particularly within the default mode system.

neuroscience↗

bioRxiv2018

Inferior parietal lobule and early visual areas support elicitation of individualized meanings during narrative listening

When listening to a narrative, the verbal expressions translate into meanings and flow of mental imagery, at best vividly immersing the keen listener into the sights, sounds, scents, objects, actions, and events in the story. However, the same narrative can be heard quite differently based on differences in listeners previous experiences and knowledge, as the semantics and mental imagery elicited by words and phrases in the story vary extensively between any given two individuals. Here, we capitalized on such inter-individual differences to disclose brain regions that support transformation of narrative into individualized propositional meanings and associated mental imagery by analyzing brain activity associated with behaviorally-assessed individual meanings elicited by a narrative. Sixteen subjects listed words best describing what had come to their minds during each 3-5 sec segment of an eight-minute narrative that they listened during fMRI of brain hemodynamic activity. Similarities in these word listings between subjects, estimated using latent-semantic analysis combined with WordNet knowledge, predicted similarities in brain hemodynamic activity in supramarginal and angular gyri as well as in cuneus. Our results demonstrate how inter-individual differences in semantic representations can be measured and utilized to identify specific brain regions that support the elicitation of individual propositional meanings and the associated mental imagery when one listens to a narrative.

neuroscience↗

bioRxiv2017

Skilled lipreaders read and listen to lips

Only a few of us are skilled lipreaders while most struggle at the task. To illuminate the poorly understood neural substrate of this variability, we estimated the similarity of brain activity during lipreading, listening, and reading of the same 8-min narrative with subjects whose lipreading skill varied extensively. The similarity of brain activity was estimated by voxel-wise comparison of the BOLD signal time courses. Inter-subject correlation of the time courses revealed that lipreading and listening are supported by the same brain areas in temporal, parietal and frontal cortices, precuneus and cerebellum. However, lipreading activated only a small part of the neural network that is active during listening/reading the narrative, demonstrating that neural processing during lipreading vs. listening/reading differs substantially. Importantly, skilled lipreading was specifically associated with bilateral activity in the superior and middle temporal cortex, which also encode auditory speech. Our novel results both confirm previous results from few previous studies using isolated speech segments as stimuli but also extend in an important way understanding of neural mechanisms of lipreading.

neuroscience↗

bioRxiv2017

Reproducibility of importance extraction methods in neural network based fMRI classification

Recent advances in machine learning allow faster training, improved performance and increased interpretability of classification techniques. Consequently, their application in neuroscience is rapidly increasing. While classification approaches have proved useful in functional magnetic resonance imaging (fMRI) studies, there are concerns regarding extraction, reproducibility and visualization of brain regions that contribute most significantly to the classification. We addressed these issues using an fMRI classification scheme based on neural networks and compared a set of methods for extraction of category-related voxel importances in three simulated and two empirical datasets. The simulation data revealed that the proposed scheme successfully detects spatially distributed and overlapping activation patterns upon successful classification. Application of the proposed classification scheme to two previously published empirical fMRI datasets revealed robust importance maps that extensively overlap with univariate maps but also provide complementary information. We conclude that importance maps are superior to univariate approaches for both detection of overlapping patterns and patterns with weak univariate information.

neuroscience↗

bioRxiv2017

Distributed Affective Space Represents Multiple Emotion Categories Across The Brain

The functional organization of human emotion systems as well as their neuroanatomical basis and segregation in the brain remains unresolved. Here we used pattern classification and hierarchical clustering to reveal and characterize the organization of discrete emotion categories in the human brain. We induced 14 emotions (6 \"basic\", such as fear and anger; and 8 \"non-basic\", such as shame and gratitude) and a neutral state in participants using guided mental imagery while their brain activity was measured with functional magnetic resonance imaging (fMRI). Twelve out of 14 emotions could be reliably classified from the fMRI signals. All emotions engaged a multitude of brain areas, primarily in midline cortices including anterior and posterior cingulate and precuneus, in subcortical regions, and in motor regions including cerebellum and premotor cortex. Similarity of subjective emotional experiences was associated with similarity of the corresponding neural activation patterns. We conclude that the emotions included in the study have discrete neural bases characterized by specific, distributed activation patterns in widespread cortical and subcortical circuits, and highlight both overlaps and differences in the locations of these for each emotion. Locally differentiated engagement of these globally shared circuits defines the unique neural fingerprint activity pattern and the corresponding subjective feeling associated with each emotion.

neuroscience↗

bioRxiv2017

The human brain views selfish behaviour towards genetic vs. non-genetic sibling differently

Previous behavioural studies have shown that humans act more altruistically towards kin. Whether and how such kinship preference translates into differential neurocognitive evaluation of social interactions has remained an open question. Here, we investigated how the human brain is engaged when viewing a moral dilemma between genetic vs. non-genetic sisters. During functional magnetic resonance imaging, a movie depicting refusal of organ donation between two sisters was shown, with participants guided to believe the sisters were related either genetically or by adoption. The participants selfreported that genetic relationship was not relevant to them, yet their brain activity told a different story. When the participants believed that the sisters were genetically related, inter-subject similarity of brain activity was significantly stronger in areas supporting response-conflict resolution, emotion regulation, and self-referential social cognition. Our results show that mere knowledge of a genetic relationship between interacting persons can robustly modulate social cognition of the perceiver.

neuroscience↗