Associations of conservatism and jumping to conclusions biases with aberrant salience and default mode network.

AIM: While conservatism bias refers to the human need for more evidence for decision-making than rational thinking expects, the jumping to conclusions (JTC) bias refers to the need for less evidence among individuals with schizophrenia/delusion compared to healthy people. Although the hippocampus-midbrain-striatal aberrant salience system and the salience, default mode (DMN), and frontoparietal networks ("triple networks") are implicated in delusion/schizophrenia pathophysiology, the associations between conservatism/JTC and these systems/networks are unclear. METHODS: Thirty-seven patients with schizophrenia and 33 healthy controls performed the beads task, with large and small numbers of bead draws to decision (DTD) indicating conservatism and JTC, respectively. We performed independent component analysis (ICA) of resting functional magnetic resonance imaging (fMRI) data. For systems/networks above, we investigated interactions between diagnosis and DTD, and main effects of DTD. We similarly applied ICA to structural and diffusion MRI to explore the associations between DTD and gray/white matter. RESULTS: We identified a significant main effect of DTD with functional connectivity between the striatum and DMN, which was negatively correlated with delusion severity in patients, indicating that the greater the anti-correlation between these networks, the stronger the JTC and delusion. We further observed the main effects of DTD on a gray matter network resembling the DMN, and a white matter network connecting the functional and gray matter networks (all P < 0.05, family-wise error [FWE] correction). Function and gray/white matter showed no significant interactions. CONCLUSION: Our results support the novel association of conservatism and JTC biases with aberrant salience and default brain mode.

Prefrontal GABA and glutamate-glutamine levels affect sustained attention.

Attention levels fluctuate during the course of daily activities. However, factors underlying sustained attention are still unknown. We investigated mechanisms of sustained attention using psychological, neuroimaging, and neurochemical approaches. Participants were scanned with functional magnetic resonance imaging (fMRI) while performing gradual-onset, continuous performance tasks (gradCPTs). In gradCPTs, narrations or visual scenes gradually changed from one to the next. Participants pressed a button for frequent Go trials as quickly as possible and withheld responses to infrequent No-go trials. Performance was better for the visual gradCPT than for the auditory gradCPT, but the 2 were correlated. The dorsal attention network was activated during intermittent responses, regardless of sensory modality. Reaction-time variability of gradCPTs was correlated with signal changes (SCs) in the left fronto-parietal regions. We also used magnetic resonance spectroscopy (MRS) to measure levels of glutamate-glutamine (Glx) and γ-aminobutyric acid (GABA) in the left prefrontal cortex (PFC). Glx levels were associated with performance under undemanding situations, whereas GABA levels were related to performance under demanding situations. Combined fMRI-MRS results demonstrated that SCs of the left PFC were positively correlated with neurometabolite levels. These findings suggest that a neural balance between excitation and inhibition is involved in attentional fluctuations and brain dynamics.

Association between enhanced carbonyl stress and decreased apparent axonal density in schizophrenia by multimodal white matter imaging.

Carbonyl stress is a condition featuring increased rich reactive carbonyl compounds, which facilitate the formation of advanced glycation end products including pentosidine. We previously reported the relationship between enhanced carbonyl stress and disrupted white matter integrity in schizophrenia, although which microstructural component is disrupted remained unclear. In this study, 32 patients with schizophrenia (SCZ) and 45 age- and gender-matched healthy volunteers (HC) were recruited. We obtained blood samples for carbonyl stress markers (plasma pentosidine and serum pyridoxal) and multi-modal magnetic resonance imaging measures of white matter microstructures including apparent axonal density (intra-cellular volume fraction (ICVF)) and orientation (orientation dispersion index (ODI)), and inflammation (free water (FW)). In SCZ, the plasma pentosidine level was significantly increased. Group comparison revealed that mean white matter values were decreased for ICVF, and increased for FW. We found a significant negative correlation between the plasma pentosidine level and mean ICVF values in SCZ, and a significant negative correlation between the serum pyridoxal level and mean ODI value in HC, regardless of age. Our results suggest an association between enhanced carbonyl stress and axonal abnormality in SCZ.

Behavioral and neural underpinnings of empathic characteristics in a Humanitude-care expert.

Background: Humanitude approaches have shown positive effects in elderly care. However, the behavioral and neural underpinnings of empathic characteristics in Humanitude-care experts remain unknown. Methods: We investigated the empathic characteristics of a Humanitude-care expert (YG) and those of age-, sex-, and race-matched controls (n = 13). In a behavioral study, we measured subjective valence and arousal ratings and facial electromyography (EMG) of the corrugator supercilii and zygomatic major muscles while participants passively observed dynamic facial expressions associated with anger and happiness and their randomized mosaic patterns. In a functional magnetic resonance imaging (MRI) study, we measured brain activity while participants passively observed the same dynamic facial expressions and mosaics. In a structural MRI study, we acquired structural MRI data and analyzed gray matter volume. Results: Our behavioral data showed that YG experienced higher subjective arousal and showed stronger facial EMG activity congruent with stimulus facial expressions compared with controls. The functional MRI data demonstrated that YG showed stronger activity in the ventral premotor cortex (PMv; covering the precentral gyrus and inferior frontal gyrus) and posterior middle temporal gyrus in the right hemisphere in response to dynamic facial expressions versus dynamic mosaics compared with controls. The structural MRI data revealed higher regional gray matter volume in the right PMv in YG than in controls. Conclusion: These results suggest that Humanitude-care experts have behavioral and neural characteristics associated with empathic social interactions.

The widespread action observation/execution matching system for facial expression processing.

Observing and understanding others' emotional facial expressions, possibly through motor synchronization, plays a primary role in face-to-face communication. To understand the underlying neural mechanisms, previous functional magnetic resonance imaging (fMRI) studies investigated brain regions that are involved in both the observation/execution of emotional facial expressions and found that the neocortical motor regions constituting the action observation/execution matching system or mirror neuron system were active. However, it remains unclear (1) whether other brain regions in the limbic, cerebellum, and brainstem regions could be also involved in the observation/execution matching system for processing facial expressions, and (2) if so, whether these regions could constitute a functional network. To investigate these issues, we performed fMRI while participants observed dynamic facial expressions of anger and happiness and while they executed facial muscle activity associated with angry and happy facial expressions. Conjunction analyses revealed that, in addition to neocortical regions (i.e., the right ventral premotor cortex and right supplementary motor area), bilateral amygdala, right basal ganglia, bilateral cerebellum, and right facial nerve nucleus were activated during both the observation/execution tasks. Group independent component analysis revealed that a functional network component involving the aforementioned regions were activated during both observation/execution tasks. The data suggest that the motor synchronization of emotional facial expressions involves a widespread observation/execution matching network encompassing the neocortex, limbic system, basal ganglia, cerebellum, and brainstem.

Crosstalk in Facial EMG and Its Reduction Using ICA.

There is ample evidence that electromyography (EMG) signals from the corrugator supercilii and zygomatic major muscles can provide valuable information for the assessment of subjective emotional experiences. Although previous research suggested that facial EMG data could be affected by crosstalk from adjacent facial muscles, it remains unproven whether such crosstalk occurs and, if so, how it can be reduced. To investigate this, we instructed participants (n = 29) to perform the facial actions of frowning, smiling, chewing, and speaking, in isolation and combination. During these actions, we measured facial EMG signals from the corrugator supercilii, zygomatic major, masseter, and suprahyoid muscles. We performed an independent component analysis (ICA) of the EMG data and removed crosstalk components. Speaking and chewing induced EMG activity in the masseter and suprahyoid muscles, as well as the zygomatic major muscle. The ICA-reconstructed EMG signals reduced the effects of speaking and chewing on zygomatic major activity, compared with the original signals. These data suggest that: (1) mouth actions could induce crosstalk in zygomatic major EMG signals, and (2) ICA can reduce the effects of such crosstalk.

Enhanced mirror neuron network activity and effective connectivity during live interaction among female subjects.

Facial expressions are indispensable in daily human communication. Previous neuroimaging studies investigating facial expression processing have presented pre-recorded stimuli and lacked live face-to-face interaction. Our paradigm alternated between presentations of real-time model performance and pre-recorded videos of dynamic facial expressions to participants. Simultaneous functional magnetic resonance imaging (fMRI) and facial electromyography activity recordings, as well as post-scan valence and arousal ratings were acquired from 44 female participants. Live facial expressions enhanced the subjective valence and arousal ratings as well as facial muscular responses. Live performances showed greater engagement of the right posterior superior temporal sulcus (pSTS), right inferior frontal gyrus (IFG), right amygdala and right fusiform gyrus, and modulated the effective connectivity within the right mirror neuron system (IFG, pSTS, and right inferior parietal lobule). A support vector machine algorithm could classify multivoxel activation patterns in brain regions involved in dynamic facial expression processing in the mentalizing networks (anterior and posterior cingulate cortex). These results indicate that live social interaction modulates the activity and connectivity of the right mirror neuron system and enhances spontaneous mimicry, further facilitating emotional contagion.

Exploration of Emotion Dynamics Sensing Using Trapezius EMG and Fingertip Temperature.

Exploration of the physiological signals associated with subjective emotional dynamics has practical significance. Previous studies have reported that the dynamics of subjective emotional valence and arousal can be assessed using facial electromyography (EMG) and electrodermal activity (EDA), respectively. However, it remains unknown whether other methods can assess emotion dynamics. To investigate this, EMG of the trapezius muscle and fingertip temperature were tested. These measures, as well as facial EMG of the corrugator supercilii and zygomatic major muscles, EDA (skin conductance level) of the palm, and continuous ratings of subjective emotional valence and arousal, were recorded while participants (n = 30) viewed emotional film clips. Intra-individual subjective-physiological associations were assessed using correlation analysis and linear and polynomial regression models. Valence ratings were linearly associated with corrugator and zygomatic EMG; however, trapezius EMG was not related, linearly or curvilinearly. Arousal ratings were linearly associated with EDA and fingertip temperature but were not linearly or curvilinearly related with trapezius EMG. These data suggest that fingertip temperature can be used to assess the dynamics of subjective emotional arousal.

Dynamic Transitions Between Brain States Predict Auditory Attentional Fluctuations.

Achievement of task performance is required to maintain a constant level of attention. Attentional level fluctuates over the course of daily activities. However, brain dynamics leading to attentional fluctuation are still unknown. We investigated the underlying mechanisms of sustained attention using functional magnetic resonance imaging (fMRI). Participants were scanned with fMRI while performing an auditory, gradual-onset, continuous performance task (gradCPT). In this task, narrations gradually changed from one to the next. Participants pressed a button for frequent Go trials (i.e., male voices) as quickly as possible and withheld responses to infrequent No-go trials (i.e., female voices). Event-related analysis revealed that frontal and temporal areas, including the auditory cortex, were activated during successful and unsuccessful inhibition of predominant responses. Reaction-time (RT) variability throughout the auditory gradCPT was positively correlated with signal changes in regions of the dorsal attention network: superior frontal gyrus and superior parietal lobule. Energy landscape analysis showed that task-related activations could be clustered into different attractors: regions of the dorsal attention network and default mode network. The number of alternations between RT-stable and erratic periods increased with an increase in transitions between attractors in the brain. Therefore, we conclude that dynamic transitions between brain states are closely linked to auditory attentional fluctuations.

Development of attentional networks during childhood and adolescence: A functional MRI study.

Attention ability is one of the most important cognitive functions. It develops mainly during school age. However, the neural basis for the typical development of attentional functions has not been fully investigated. To clarify the development of the aforementioned function and its neural basis, this study examined brain function in children and adolescents during the performance of an attention network test (ANT) using functional magnetic resonance imaging. One hundred and sixty-three volunteers (8-23 years, 80 female) participated in this study. Using a modified version of ANT, we assessed the efficiency of two attentional functions-orienting and executive attention-by measuring how reaction time is affected by spatial cue location and flanker congruency and examined the functional brain areas-attentional networks-associated with two attentional functions. Consistent with the findings of previous studies, the superior parietal lobule, visual association cortex, left precentral gyrus, and supplementary motor area were activated during the orienting attention, while the anterior cingulate cortex, visual association cortex, lateral prefrontal cortex, thalamus, and caudate were activated during the executive attention. Moreover, negative correlations with age were found for activations in the inferior frontal gyrus, dorsomedial prefrontal cortex, and caudate nucleus in the orienting attention, while no correlations with age related to executive attention were found. In conclusion, this study revealed common and distinct features in the neural basis of the attentional functions in children and adolescents compared with that of adults and their developmental changes with age.

The structural neural correlates of atypical facial expression recognition in autism spectrum disorder.

Previous studies have demonstrated that individuals with autism spectrum disorder (ASD) are worse at recognizing facial expressions than are typically developing (TD) individuals. The present study investigated the differences in structural neural correlates of emotion recognition between individuals with and without ASD using voxel-based morphometry (VBM). We acquired structural MRI data from 27 high-functioning adults with ASD and 27 age- and sex-matched TD individuals. The ability to recognize facial expressions was measured using a label-matching paradigm featuring six basic emotions (anger, disgust, fear, happiness, sadness, and surprise). The behavioural task did not find deficits of emotion recognition in ASD after controlling for intellectual ability. However, the VBM analysis for the region of interest showed a positive correlation between the averaged percent accuracy across six basic emotions and the grey matter volume of the right inferior frontal gyrus in TD individuals, but not in individuals with ASD. The VBM for the whole brain region under each emotion condition revealed a positive correlation between the percent accuracy for disgusted faces and the grey matter volume of the left dorsomedial prefrontal cortex in individuals with ASD, but not in TD individuals. The different pattern of correlations suggests that individuals with and without ASD use different processing mechanisms for recognizing others' facial expressions.

Morphological invariant of the midsagittal deep brain anatomy between humans and African great apes.

OBJECTIVES: Efforts have been made to mathematically reconstruct the brain morphology from human fossil crania to clarify the evolutionary changes in the brain that are associated with the emergence of human cognitive ability. However, because conventional reconstruction methods are based solely on the endocranial shape, deep brain structures cannot be estimated with sufficient accuracy. Our study aims to investigate the possible morphological correspondence between the cranial and deep brain morphologies based on humans and African great apes, with the goal of a more precise reconstruction of fossil brains. MATERIALS AND METHODS: Midsagittal endocranial and deep brain landmarks were obtained from magnetic resonance images of humans and three species of African great apes. The average midsagittal endocranial profile of all four species was calculated after Procrustes registration. The spatial deformation function from each of the endocranial profiles to the average endocranial profile was defined, and the brain landmarks enclosed in the endocranium were transformed using the deformation function to evaluate the interspecific variabilities of the positions of the brain landmarks on the average endocranial profile. RESULTS: The interspecific differences in the shape-normalized positions of the corpus callosum, anterior commissure, thalamus center, and brainstem were approximately within the range of 2% of the human cranial length, indicating that the interspecific variabilities of the positions of these deep brain structures were relatively small among the four species. DISCUSSION: Such an invariant relationship of the deep brain structure and the endocranium that encloses the brain can potentially be utilized to reconstruct the brains of fossil hominins.

Physical correlates of human-like softness elicit high tactile pleasantness.

Touching an object can elicit affective sensations. Because these sensations are critical for social interaction, tactile preferences may be adapted to the characteristics of the human body. We have previously shown that compliance, a physical correlate of softness, increased the tactile pleasantness of a deformable surface. However, the extent to which object compliance similar to the human body elicits tactile pleasantness remains unknown. We addressed this question by using a wide range of compliances and by measuring the distribution of compliance of human body parts. The participants numerically estimated the perceived pleasantness or softness while pushing tactile stimuli with their right index fingers. The perceived softness monotonically increased with increasing compliance and then leveled off around the end of the stimulus range. By contrast, pleasantness showed an inverse U pattern as a function of compliance, reaching the maximum between 5 and 7 mm/N. This range of compliance was within that for both hand and arm. These results indicate that objects with similar compliance levels as those of human body parts yield the highest pleasantness when pushing them.

The extrastriate body area is involved in reciprocal imitation of hand gestures, vocalizations, and facial expressions: A univariate and multivariate fMRI study.

The extrastriate body area (EBA) in the lateral occipito-temporal cortex has an important role in reciprocal interaction, as it detects congruence between self and other's hand actions. However, it is unclear whether the EBA can detect congruence regardless of the type of action. In the present study, we examined the neural substrate underlying congruence detection of three types of actions: hand gestures, vocalizations, and facial expressions. A univariate analysis revealed a congruency effect, especially for imitating action, for all three types of actions in the EBA. A multi-voxel pattern analysis classifier in the EBA was able to distinguish between initiating interaction from responding to interaction in all experiments. Correspondingly, the congruency effect in the EBA revealed by univariate analysis was stronger for responding to than for initiating interaction. These findings suggest that the EBA might contribute to detect congruence regardless of the body part used (i.e. face or hand) and the type of action (i.e. gestural or vocal). Moreover, initiating and responding to interaction might be processed differently within the EBA. This study highlights the role of the EBA in comparing between self and other's actions beyond hand actions.Running head: Function of EBA in reciprocal imitation.

Functional heterogeneity in the left lateral posterior parietal cortex during visual and haptic crossmodal dot-surface matching.

BACKGROUND: Vision and touch are thought to contribute information to object perception in an independent but complementary manner. The left lateral posterior parietal cortex (LPPC) has long been associated with multisensory information processing, and it plays an important role in visual and haptic crossmodal information retrieval. However, it remains unclear how LPPC subregions are involved in visuo-haptic crossmodal retrieval processing. METHODS: In the present study, we used an fMRI experiment with a crossmodal delayed match-to-sample paradigm to reveal the functional role of LPPC subregions related to unimodal and crossmodal dot-surface retrieval. RESULTS: The visual-to-haptic condition enhanced the activity of the left inferior parietal lobule relative to the haptic unimodal condition, whereas the inverse condition enhanced the activity of the left superior parietal lobule. By contrast, activation of the left intraparietal sulcus did not differ significantly between the crossmodal and unimodal conditions. Seed-based resting connectivity analysis revealed that these three left LPPC subregions engaged distinct networks, confirming their different functions in crossmodal retrieval processing. CONCLUSION: Taken together, the findings suggest that functional heterogeneity of the left LPPC during visuo-haptic crossmodal dot-surface retrieval processing reflects that the left LPPC does not simply contribute to retrieval of past information; rather, each subregion has a specific functional role in resolving different task requirements.

Neurocognitive Mechanisms Underlying Social Atypicalities in Autism: Weak Amygdala's Emotional Modulation Hypothesis.

Autism spectrum disorder (ASD) is a neurodevelopmental condition associated with atypicalities in social interaction. Although psychological and neuroimaging studies have revealed divergent impairments in psychological processes (e.g., emotion and perception) and neural activity (e.g., amygdala, superior temporal sulcus, and inferior frontal gyrus) related to the processing of social stimuli, it remains difficult to integrate these findings. In an effort to resolve this issue, we review our psychological and functional magnetic resonance imaging (fMRI) findings and present a hypothetical neurocognitive model. Our psychological study showed that emotional modulation of reflexive joint attention is impaired in individuals with ASD. Our fMRI study showed that modulation from the amygdala to the neocortex during observation of dynamic facial expressions is reduced in the ASD group. Based on these findings and other evidence, we hypothesize that weak modulation from the amygdala to the neocortex-through which emotion rapidly modulates various types of perceptual, cognitive, and motor processing functions-underlies the social atypicalities in individuals with ASD.

Physiological correlates of subjective emotional valence and arousal dynamics while viewing films.

An exploration of the physiological correlates of subjective emotional states has theoretical and practical significance. Previous studies have reported that subjective valence and arousal correspond to facial electromyography (EMG) and electrodermal activity (EDA), respectively, across stimuli. However, the reported results were inconsistent, no study investigated subjective-physiological concordance across time, and measures of arousal remain controversial. To investigate these issues, while healthy adults (n = 20) viewed emotional films, we assessed overall and continuous ratings of valence and arousal and recorded EMG from the corrugator supercilii and zygomatic major, EDA from the palms and forehead, and nose-tip temperature. The corrugator and zygomatic EMG were negatively and positively associated with valence ratings, respectively, across stimuli and time. EDA (both sites) and nose-tip temperature were positively and negatively associated with arousal ratings, respectively, across stimuli and time. It is concluded that subjective emotional valence and arousal dynamics have specific physiological correlates.

Amygdala activity related to perceived social support.

Perceived social support enhances well-being and prevents stress-related ill-being. A recent structural neuroimaging study reported that the amygdala volume is positively associated with perceived social support. However, it remains unknown how neural activity in this region and functional connectivity (FC) between this and other regions are related to perceived social support. To investigate these issues, resting-state functional magnetic resonance imaging was performed to analyze the fractional amplitude of low-frequency fluctuation (fALFF). Perceived social support was evaluated using the Multidimensional Scale of Perceived Social Support (MSPSS). Lower fALFF values in the bilateral amygdalae were associated with higher MSPSS scores. Additionally, stronger FC between the left amygdala and right orbitofrontal cortex and between the left amygdala and bilateral precuneus were associated with higher MSPSS scores. The present findings suggest that reduced amygdala activity and heightened connectivity between the amygdala and other regions underlie perceived social support and its positive functions.

Differences between children and adults in functional connectivity between the inferior frontal gyrus and extrastriate body area for gestural interaction.

Gestural interaction, where a person initiates interaction (initiator) and another person responds to it (follower), changes during development. The neural network comprising the inferior frontal gyrus (IFG), inferior parietal lobule (IPL), and the lateral occipito-temporal cortex (LOTC) is relevant to gestural interaction. The LOTC includes the extrastriate body area (EBA). Activation of these brain regions depends on the initiating/following role in adults. We conducted functional magnetic resonance imaging study on 18 children and 18 adults, to elucidate developmental changes of the neural mechanism underlying gestural interaction. We manipulated the initiating/following role (initiating/following) and congruency (congruent/incongruent) of executed and observed actions. After analyzing regional brain activity, we assessed psycho-physiological interaction to examine functional connectivity. Activation in the IFG and connectivity between the IFG and EBA in the Initiating rather than Following condition, which might be associated with evaluating social relevance, was stronger in adults than in children. The increase of the incongruency effect in the following condition (relative to the initiating condition) in the bilateral IPL was significantly attenuated in children compared with adults. These results suggest that the fronto-parieto-temporal network, involved in gestural interactions, undergoes developmental changes.

Visual Body Part Representation in the Lateral Occipitotemporal Cortex in Children/Adolescents and Adults.

The lateral occipitotemporal cortex (LOTC) that responds to human bodies and body parts has been implicated in social development and neurodevelopmental disorders like autism spectrum disorder (ASD). Neuroimaging studies using a representational similarity analysis (RSA) revealed that body representation in the LOTC of typically developing (TD) adults is categorized into 3 clusters: action effector body parts, noneffector body parts, and face parts. However, its organization of younger people (i.e., children and adolescents) and its association with individual traits remain unclear. In this functional MRI study, TD adults and children/adolescents observed photographs of hands, feet, arms, legs, chests, waists, upper/lower faces, the whole body, and chairs. The univariate analysis showed that fewer child/adolescent participants showed left LOTC activation in response to whole-body images (relative to those of chairs) than adult participants. Contrastingly, the RSA on both age groups revealed a comparable body representation with 3 clusters of body parts in the bilateral LOTC. Hence, this result indicates that, although response to whole-body images can differ, LOTC body part representations for children/ adolescents and adults are highly similar. Furthermore, sensory atypicality is associated with spatial LOTC organization, suggesting the importance of this region for understanding individual difference, which is frequently observed in ASD.