When "more for others, less for self" leads to co-benefits: A tri-MRI dyad-hyperscanning study.

Unselfishness is admired, especially when collaborations between groups of various scales are urgently needed. However, its neural mechanisms remain elusive. In a tri-MRI dyad-hyperscanning experiment involving 26 groups, each containing 4 participants as two rotating pairs in a coordination game, we sought to achieve reciprocity, or "winning in turn by the two interacting players," as the precursor to unselfishness. Due to its critical role in social processing, the right temporal-parietal junction (rTPJ) was the seed for both time domain (connectivity) and frequency domain (i.e., coherence) analyses. For the former, negative connectivity between the rTPJ and the mentalizing network areas (e.g., the right inferior parietal lobule, rIPL) was identified, and such connectivity was further negatively correlated with the individual's final gain, supporting our task design that "rewarded" the reciprocal participants. For the latter, cerebral coherences of the rTPJs emerged between the interacting pairs (i.e., within-group interacting pairs), and the coupling between the rTPJ and the right superior temporal gyrus (rSTG) between the players who were not interacting with each other (i.e., within-group noninteracting pairs). These coherences reinforce the hypotheses that the rTPJ-rTPJ coupling tracks the collaboration processes and the rTPJ-rSTG coupling for the emergence of decontextualized shared meaning. Our results underpin two social roles (inferring others' behavior and interpreting social outcomes) subserved by the rTPJ-related network and highlight its interaction with other-self/other-concerning brain areas in reaching co-benefits among unselfish players.

Is increased activation in the fusiform face area to Greebles a result of appropriate expertise training or caused by Greebles' face likeness?

Background: In 2011, Brants et al. trained eight individuals to become Greeble experts and found neuronal inversion effects [NIEs; i.e., higher fusiform face area (FFA) activity for upright, rather than inverted Greebles]. These effects were also found for faces, both before and after training. By claiming to have replicated the seminal Greeble training study by Gauthier and colleagues in 1999, Brants et al. interpreted these results as participants viewing Greebles as faces throughout training, contrary to the original argument of subjects becoming Greeble experts only after training. However, Brants et al.'s claim presents two issues. First, their behavioral training results did not replicate those of Gauthier and Tarr conducted in 1997 and 1998, raising concerns of whether the right training regime had been adopted. Second, both a literature review and meta-analysis of NIEs in the FFA suggest its impotency as an index of the face(-like) processing. Objectives: To empirically evaluate these issues, the present study compared two documented training paradigms Gauthier and colleagues in 1997 and 1998, and compared their impact on the brain. Methods: Sixteen NCKU undergraduate and graduate students (nine girls) were recruited. Sixty Greeble exemplars were categorized by two genders, five families, and six individual levels. The participants were randomly divided into two groups (one for Greeble classification at all three levels and the other for gender- and individual-level training). Several fMRI tasks were administered at various time points, specifically, before training (1st), during training (2nd), and typically no <24 h after reaching expertise criterion (3rd). Results: The ROI analysis results showed significant increases in the FFA for Greebles, and a clear neural "adaptation," both only in the Gauthier97 group and only after training, reflecting clear modulation of extensive experiences following an "appropriate" training regime. In both groups, no clear NIEs for faces nor Greebles were found, which was also in line with the review of extant studies bearing this comparison. Conclusion: Collectively, these results invalidate the assumptions behind Brants et al.'s findings.

Seed correlation analysis based on brain region activation for ADHD diagnosis in a large-scale resting state data set.

Background: Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder of multifactorial pathogenesis, which is often accompanied by dysfunction in several brain functional connectivity. Resting-state functional MRI have been used in ADHD, and they have been proposed as a possible biomarker of diagnosis information. This study's primary aim was to offer an effective seed-correlation analysis procedure to investigate the possible biomarker within resting state brain networks as diagnosis information. Method: Resting-state functional magnetic resonance imaging (rs-fMRI) data of 149 childhood ADHD were analyzed. In this study, we proposed a two-step hierarchical analysis method to extract functional connectivity features and evaluation by linear classifiers and random sampling validation. Result: The data-driven method-ReHo provides four brain regions (mPFC, temporal pole, motor area, and putamen) with regional homogeneity differences as second-level seeds for analyzing functional connectivity differences between distant brain regions. The procedure reduces the difficulty of seed selection (location, shape, and size) in estimations of brain interconnections, improving the search for an effective seed; The features proposed in our study achieved a success rate of 83.24% in identifying ADHD patients through random sampling (saving 25% as the test set, while the remaining data was the training set) validation (using a simple linear classifier), surpassing the use of traditional seeds. Conclusion: This preliminary study examines the feasibility of diagnosing ADHD by analyzing the resting-state fMRI data from the ADHD-200 NYU dataset. The data-driven model provides a precise way to find reliable seeds. Data-driven models offer precise methods for finding reliable seeds and are feasible across different datasets. Moreover, this phenomenon may reveal that using a data-driven approach to build a model specific to a single data set may be better than combining several data and creating a general model.

Distinct cerebral coherence in task-based fMRI hyperscanning: cooperation versus competition.

This study features an functional magnetic resonance imaging (fMRI) hyperscanning experiment from 2 sites, 305 km apart. The experiment contains 2 conditions: the dyad collaborated to win and then split the reward in the cooperation condition, whereas the winner took all the reward in the competition condition, thereby resulting in dynamic strategic interactions. To calculate the cerebral coherence in such jittered event-related fMRI tasks, we first iteratively estimated the feedback-related blood oxygenation level-dependent responses of each trial, using 8 finite impulse response functions (16 s) and then concatenated the beta volume series. With the right temporal-parietal junction (rTPJ) as the seed, the interpersonal connected brain areas were separately identified: the right superior temporal gyrus (rSTG) (cooperation) and the left precuneus (lPrecuneus) (competition), both peaking at the designated frequency bin (1/16 s = 0.0625 Hz), but not in permuted pairs. In addition, the extended coherence analyses on shorter and longer concatenated volumes verified that only in the optimal trial frequency did the rTPJ-rSTG and rTPJ-lPrecuneus couplings peak. In sum, our approach both showcases a flexible analysis method that widens the applicability of interpersonal coherence in the rapid event-related fMRI hyperscanning and reveals a context-based inter-brain coupling between interacting pairs during cooperation and during competition.

A brain network that supports consensus-seeking and conflict-resolving of college couples' shopping interaction.

One of the typical campus scenes is the social interaction between college couples, and the lesson couples must keep learning is to adapt to each other. This fMRI study investigated the shopping interactions of 30 college couples, one lying inside and the other outside the scanner, beholding the same item from two connected PCs, making preference ratings and subsequent buy/not-buy decisions. The behavioral results showed the clear modulation of significant others' preferences onto one's own decisions, and the contrast of the "shop-together vs. shop-alone", and the "congruent (both liked or disliked the item, 68%) vs. incongruent (one liked but the other disliked, and vice versa)" together trials, both revealed bilateral temporal parietal junction (TPJ) among other reward-related regions, likely reflecting mentalizing during preference harmony. Moreover, when contrasting "own-high/other-low vs. own-low/other-high" incongruent trials, left anterior inferior parietal lobule (l-aIPL) was parametrically mapped, and the "yield (e.g., own-high/not-buy) vs. insist (e.g., own-low/not-buy)" modulation further revealed left lateral-IPL (l-lIPL), together with left TPJ forming a local social decision network that was further constrained by the mediation analysis among left TPJ-lIPL-aIPL. In sum, these results exemplify, via the two-person fMRI, the neural substrate of shopping interactions between couples.

The neural substrate of self- and other-concerned wellbeing: An fMRI study.

Happiness, or Subjective Well-Being (SWB), is generally considered as a peaceful and satisfied state accompanied by consistent and optimistic mood. Due to its subjective and elusive nature, however, wellbeing has only been scarcely investigated in the neuroimaging literature. In this study, we investigated its neural substrates by characterizing two different perspectives: self- or other-concerned wellbeing. In the present study, 22 participants evaluated the subjective happiness (with button presses 1 to 4) to 3 categories (intra- and inter-personal and neutral) of pre-rated pictures in a slow event-related fMRI. Because wellbeing is constantly featured by pleasure feelings after self-inspection, we predict that happier conditions, featured by "intra-personal vs. neutral" and "inter-personal vs. neutral" conditions, should yield higher BOLD activities in overlapping reward- and self-related regions. Indeed, medial prefrontal (mPFC), pregenual ACC (pACC), precuneus and posterior cingulate cortex (PCC) were revealed both by General Linear Model (GLM) (categorical contrasts) and parametric modulations (correlations with rating 1-4s), specifically, more connectivity between nucleus accumbens (NAcc) and mPFC, via additional psychophysiological interaction, or PPI, analyses. More interestingly, GLM and multivariate searchlight analyses jointly reveal the subdivision of mPFC and the PCC/precuneus, with anterior mPFC and dorsal PCC/precuneus more for interpersonal, posterior mPFC and ventral PCC/precuneus more for intrapersonal, SWB, respectively. Taken together, these results are not only consistent with the "cortical midline hypothesis of the self", but also extending the "spatial gradients of self-to-other-concerned processing" from mPFC to including both mPFC and PCC/precuneus, making them two "hubs" of self-to-other-concerned wellbeing network.

Musicians and non-musicians' different reliance of features in consonance perception: a behavioral and ERP study.

OBJECTIVE: The aim of this study was to compare the different features that musicians and non-musicians rely upon when they discern consonant and dissonant intervals. Previous studies have addressed this issue from the perspective of either the frequency ratio (Western music theory) or the frequency difference (psychoacoustics), but have not considered both features in a single and balanced study. METHODS: Twelve musicians and twelve non-musicians judged musical consonance at various 50-500 Hz intervals, orthogonally selected from across the "pitch interval" and "roughness" spectrum. Both behavioral and event-related potential (ERP) data were collected separately. RESULTS: Behavioral results demonstrated that while musicians relied upon pitch intervals (between perfect fifths and tritones, with 95% accuracy), non-musicians performed around chance. The latter performance could, however, be sub-divided into "rough tritone and non-rough perfect-fifth" (70-80%) and "non-rough tritone and rough perfect-fifth" combinations (25-30%), suggesting non-musicians' reliance on the roughness dimension. ERP components revealed corresponding P2 (200-250 ms) amplitude differences in the Fz and Cz channels for the "tritones vs. perfect fifths" comparison in musicians, and by the "rough vs. non-rough" comparison in the non-musicians. In addition, N1 (∼100 ms) and N2 (300-400 ms) components also revealed difference in Fz, F3, F4, FCz, Cz and CPz electrodes for "tritones vs. perfect fifths" in musicians. In the non-musicians, a stronger negative N2 for rough than for non-rough stimuli was found at F4 and Cz. CONCLUSION: Together, these results suggest that musicians and non-musicians rely upon pitch intervals and sensory roughness, respectively, for consonance/dissonance perception. SIGNIFICANCE: To our knowledge, this is the first study to compare independently across the pitch interval and roughness spectrum. Our results further support the brain plasticity as a result of musical training in consonance perception.

Using functional magnetic resonance imaging to explore the flashed face distortion effect.

The flashed face distortion (FFD) effect was coined by Tangen, Murphy, and Thompson (2011) in their second-place winner of the 2012 Best Illusion of the Year Contest. The FFD arises when people view various eye-aligned faces that are sequentially flashed in the visual periphery, and gradually the faces appear to be deformed and grotesque. In this functional magnetic resonance imaging (fMRI) study, participants were presented with four conditions: (a) one face pair changing only its illumination; (b) two and (c) three alternating face pairs; and (d) nonrepeated face pairs. Participants rated the magnitude of each illusion immediately after each block. Results showed that the receptive region of the early visual cortex (V1-V4), and category-selective areas such as the fusiform face area (FFA) and occipital face area (OFA), responded proportionally to the participants' rated FFD strength. A random-effects voxelwise analysis further revealed positively correlated areas (including the medial and superolateral frontal areas) and negatively correlated areas (including the precuneus, postcentral gyrus, right insula, and bilateral middle frontal gyri) with respect to participants' ratings. Time series correlations among these nine ROIs (four positive and five negative) indicated that most participants showed a clustering of the two separate ROI types. Exploratory factor analysis (EFA) also demonstrated the segregation of the positive and negative ROIs; additionally, two subsystems were identified within the negative ROIs. These results suggest that the FFD is mediated by at least two networks: one that is likely responsible for perception and another that is likely responsible for subjective feelings and engagement.

Is region-of-interest overlap comparison a reliable measure of category specificity?

Analysis of the degree of overlap between functional magnetic resonance imaging-derived regions of interest (ROIs) has been used to assess the functional convergence and/or segregation of category-selective brain areas. An examination of the extant literature reveals no consistent usage for how such overlap is calculated, nor any systematic comparison between different methods. We argue that how ROI overlap is computed, especially the choice of the denominator in the formula, can profoundly affect the results and interpretation of such an analysis. To do this, we compared the overlap of the FFA-FFA (fusiform face area) and FFA-FGA (fusiform Greeble-selective area) in a localizer study testing both Greeble novices and experts. When using a single ROI as the denominator, we found a significant difference in FFA-FFA versus FFA-FGA overlap, consistent with the result of a previous study arguing for face specificity of the FFA [Rhodes, G., Byatt, G., Michie, P. T., & Puce, A. Is the fusiform face area specialized for faces, individuation, or expert individuation? J Cogn Neurosci, 16, 189-203, 2004]. However, these ROI overlap differences disappeared when the denominator combined both of the involved ROIs, and the patterns of such overlap comparisons were dependent on given statistical thresholds. We also found proportionally decreasing FFA-FFA overlap with increasing center-of-FFA distance, resolving an apparent contradiction between the consistency of the location of the FFA and the seemingly low FFA-FFA overlap. Finally, Monte Carlo simulations revealed the most stable formula-the most resistant to ROI size variations-to be the average of the two single-ROI-denominator-based overlap indices. In sum, ROI overlap analysis is not a reliable tool for assessing category specificity, and caution should be exercised with regard to ROI overlap definition, underlying assumptions, and interpretation.

Visual expertise with nonface objects leads to competition with the early perceptual processing of faces in the human occipitotemporal cortex.

Human electrophysiological studies have found that the processing of faces and other objects differs reliably at approximately 150 ms after stimulus onset, faces giving rise to a larger occipitotemporal field potential on the scalp, termed the N170. We hypothesize that visual expertise with nonface objects leads to the recruitment of early face-related categorization processes in the occipitotemporal cortex, as reflected by the N170. To test this hypothesis, the N170 in response to laterally presented faces was measured while subjects concurrently viewed centrally presented, novel, nonface objects (asymmetric "Greebles"). The task was simply to report the side of the screen on which each face was presented. Five subjects were tested during three event-related potential sessions interspersed throughout a training protocol during which they became experts with Greebles. After expertise training, the N170 in response to faces was substantially decreased ( approximately 20% decrease in signal relative to that when subjects were novices) when concurrently processing a nonface object in the domain of expertise, but not when processing untrained objects of similar complexity. Thus, faces and nonface objects in a domain of expertise compete for early visual categorization processes in the occipitotemporal cortex.