Motivated for near impossibility: How task type and reward modulate task enjoyment and the striatal activation for extremely difficult task.

Economic and decision-making theories suppose that people would disengage from a task with near zero success probability, because this implicates little normative utility values. However, humans often are motivated for an extremely challenging task, even without any extrinsic incentives. The current study aimed to address the nature of this challenge-based motivation and its neural correlates. We found that, when participants played a skill-based task without extrinsic incentives, their task enjoyment increased as the chance of success decreased, even if the task was almost impossible to achieve. However, such challenge-based motivation was not observed when participants were rewarded for the task or the reward was determined in a probabilistic manner. The activation in the ventral striatum/pallidum tracked the pattern of task enjoyment. These results suggest that people are intrinsically motivated to challenge a nearly impossible task but only when the task requires certain skills and extrinsic rewards are unavailable.

Association between the Pittsburgh sleep quality index and white matter integrity in healthy adults: a whole-brain magnetic resonance imaging study.

To disclose possible associations between poorer sleep quality and structural brain alterations in a non-psychiatric healthy population, this study investigated the association between the Pittsburgh sleep quality index (PSQI) and brain correlates, using a whole-brain approach. This study included 371 right-handed healthy adults (138 males, mean age: 46.4 ± 14.0 years [range: 18-75]) who were right-handed. Subjective sleep quality was assessed using the Japanese version of the PSQI (PSQI-J), and the cutoff score for poor subjective sleep quality was set at ≥ 6. Voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) were performed to examine whether a higher score of the PSQI-J indicates, poorer sleep quality is associated with gray matter volume and white matter microstructure alternations, respectively. Among the participants, 38.8% had a PSQI-J cutoff score of ≥ 6. VBM did not reveal any correlation between PSQI-J scores and gray matter volume. However, DTI revealed that PSQI-J global scores were significantly and negatively correlated with diffuse white matter fractional anisotropy (FA) values (p < 0.05, corrected). Moreover, the PSQI-J sleep disturbance and use of sleep medication component scores were significantly and negatively correlated with right anterior thalamic radiation and diffuse white matter FA values, respectively (p < 0.05, corrected). There were no significant differences in gray matter volume and white matter metrics (FA, axial, radial, and mean diffusivities) between the groups with PSQI-J scores above or below the cutoff. Our findings suggest that lower sleep quality, especially the use of sleep medication, is associated with impaired white matter integrity in healthy adults. Limitations of this study are relatively small number of participants and cross-sectional design. Fine sleep quality, possibly preventing the use of sleep medication, may contribute to preserve white matter integrity in the brain of healthy adults. Supplementary Information: The online version contains supplementary material available at 10.1007/s41105-022-00442-0.

Association of body mass index and its classifications with gray matter volume in individuals with a wide range of body mass index group: A whole-brain magnetic resonance imaging study.

Aim: To examine the association of body mass index (BMI) [kg/m2] and its classifications (underweight [BMI < 18.5], normal [18.5 ≤ BMI < 25], overweight [25 ≤ BMI < 30], and obese [BMI ≥ 30]) with brain structure in individuals with a wide range of BMI group. Materials and methods: The participants included 382 right-handed individuals (mean age: 46.9 ± 14.3 years, 142 men and 240 women). The intelligence quotient was assessed using the Japanese Adult Reading Test. Voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) were performed to analyze the association of BMI and its classifications with gray and white matter structures, respectively. Results: According to VBM, BMI was significantly and negatively correlated with the bilateral cerebellum exterior volumes. In group comparisons, the right cerebellum exterior volume was significantly lower in the overweight or obese group than in the underweight or normal group, while the bilateral cuneus and calcarine cortex, left cuneus, and left precuneus volume was significantly lower in the underweight group than in the non-underweight group. Sex-related stratification analyses for VBM revealed that BMI was significantly and negatively correlated with the bilateral cerebellum exterior volumes only in women. In group comparisons, the left cerebellum exterior volume was significantly lower in obese women than in non-obese women. The left thalamus proper and the right cerebellum exterior volumes were significantly lower in overweight or obese group than in underweight or normal group in men and women, respectively. The bilateral cuneus and calcarine cortex, left cuneus and carcarine cortex, and bilateral cuneus volume was significantly lower in underweight men than in non-underweight men. In contrast, there were no notable findings on DTI. Conclusion: Our results suggest association of continuous BMI, being overweight or obese, and being underweight with decreased gray matter volume in individuals with a wide range of BMI group. Furthermore, sex-related differences are seen in the association of BMI and its classifications with regional gray matter volume reductions. Abnormally high or low BMIs may have a negative influence on regional gray matter volumes.

Gut permeability and its clinical relevance in schizophrenia.

AIM: We aimed to examine the gut permeability in patients with schizophrenia and its relevance to schizophrenia symptoms, medication, cognitive functions, and blood immune markers. METHODS: We selected 22 patients with schizophrenia (mean age: 37.9 ± 10.5 years) comprising 9 men and 13 women. Furthermore, we included 86 healthy controls (mean age: 43.5 ± 11.0 years) comprising 41 men and 45 women. All participants were biologically unrelated and of Japanese descent. We used the Positive and Negative Syndrome Scale (PANSS) and Brief Assessment of Cognition in Schizophrenia (BACS) to measure the severity of schizophrenia symptoms and cognitive functions, respectively. The lactulose-mannitol loading test was used to measure the permeability of the small intestine. Furthermore, we used the lactulose to mannitol ratio (LMR) as an index of gut permeability. We measured the C-reactive protein and natural killer (NK) cell activity in the blood as highly sensitive immune markers. RESULTS: The patients had a significantly higher rate of "leaky gut" (defined as LMR ≥ 0.1) compared to the control group (22.7% vs. 5.8%, odds ratio: 4.8 [95% confidence interval, 1.2-18.3], Fisher's exact test, P = 0.03). There was no significant correlation between the LMR and PANSS scores or in the daily antipsychotic dose. In addition, the LMR was negatively correlated with the total Z-score of the BACS and NK cell activity in the patients. CONCLUSIONS: Our results suggest a higher rate of abnormally increased gut permeability in patients with schizophrenia than in controls. Moreover, gut permeability may be related to the cognitive and cellular immunity function of patients with schizophrenia.

An fMRI Investigation into the Effects of Ketogenic Medium-Chain Triglycerides on Cognitive Function in Elderly Adults: A Pilot Study.

Evidence suggests that oral intake of medium-chain triglycerides (MCTs), which promote the production of ketone bodies, may improve cognitive functions in elderly people; however, the underlying brain mechanisms remain elusive. We tested the hypothesis that cognitive improvement accompanies physiological changes in the brain and reflects the use of ketone bodies as an extra energy source. To this end, by using functional magnetic resonance imaging, cerebral blood oxygenation level-dependent (BOLD) signals were measured while 20 healthy elderly subjects (14 females and 6 males; mean age: 65.7 ± 3.9 years) were engaged in executive function tasks (N-back and Go-Nogo) after ingesting a single MCT meal (Ketonformula®) or placebo meal in a randomized, double-blind placebo-controlled design (UMIN000031539). Morphological characteristics of the brain were also examined in relation to the effects of an MCT meal. The MCT meal improved N-back task performance, and this was prominent in subjects who had reduced grey matter volume in the dorsolateral prefrontal cortex (DLPFC), a region known to promote executive functions. When the participants were dichotomized into high/low level groups of global cognitive function at baseline, the high group showed improved N-back task performance, while the low group showed improved Go-Nogo task performance. This was accompanied by decreased BOLD signals in the DLPFC, indicative of the consumption of ketone bodies as an extra energy source.

Effect of Lacticaseibacillus paracasei Strain Shirota on Improvement in Depressive Symptoms, and Its Association with Abundance of Actinobacteria in Gut Microbiota.

We previously reported lower counts of lactobacilli and Bifidobacterium in the gut microbiota of patients with major depressive disorder (MDD), compared with healthy controls. This prompted us to investigate the possible efficacy of a probiotic strain, Lacticaseibacillus paracasei strain Shirota (LcS; basonym, Lactobacillus casei strain Shirota; daily intake of 8.0 × 1010 colony-forming units), in alleviating depressive symptoms. A single-arm trial was conducted on 18 eligible patients with MDD or bipolar disorder (BD) (14 females and 4 males; 15 MDD and 3 BD), assessing changes in psychiatric symptoms, the gut microbiota, and biological markers for intestinal permeability and inflammation, over a 12-week intervention period. Depression severity, evaluated by the Hamilton Depression Rating Scale, was significantly alleviated after LcS treatment. The intervention-associated reduction of depressive symptoms was associated with the gut microbiota, and more pronounced when Bifidobacterium and the Atopobium clusters of the Actinobacteria phylum were maintained at higher counts. No significant changes were observed in the intestinal permeability or inflammation markers. Although it was difficult to estimate the extent of the effect of LcS treatment alone, the results indicated that it was beneficial to alleviate depressive symptoms, partly through its association with abundance of Actinobacteria in the gut microbiota.

Performance on the Wechsler Adult Intelligence Scale (WAIS) in Japanese patients with bipolar and major depressive disorders in euthymic and depressed states.

AIM: This study aimed to examine the cognitive performance of patients with bipolar disorder (BD) stratified by illness phase compared to that of patients with major depressive disorder (MDD) and healthy controls. METHODS: Participants were 139 patients with BD (55 euthymic and 84 depressed), 311 patients with MDD (88 euthymic and 223 depressed), and 386 healthy controls who underwent the Wechsler Adult Intelligence Scale-Revised or the Third Edition. They were non-elderly Japanese individuals with normal estimated premorbid intelligence quotient (IQ; >90), group-matched for age, sex, and premorbid IQ. RESULTS: The depressed BD group showed significantly lower scores on verbal IQ, performance IQ, full-scale IQ, and three group indexes of perceptual organization, working memory, and processing speed when compared with healthy controls (all P < 0.001). All IQs and working memory index were also significantly lower than those of the depressed MDD group. The depressed MDD group scored significantly lower than controls in performance IQ (P < 0.001), full-scale IQ, and only in the index of processing speed (P < 0.001). The euthymic BD group scored significantly lower than controls in performance IQ (P = 0.004), whereas the euthymic MDD group scored significantly lower than controls only in processing speed (P = 0.030). CONCLUSION: Patients with BD appear to have global and more intense cognitive impairments in depressed states compared with those with MDD whose impairments seem to be apparent only in processing speed in the Wechsler Adult Intelligence Scale. Attenuated impairments appear to exist in euthymic states of both patients.

Association between obesity and white matter microstructure impairments in patients with schizophrenia: A whole-brain magnetic resonance imaging study.

AIM: We aimed to examine the possible association of obesity (body mass index [BMI] ≥ 30) with symptoms, psychotropic medication, and whole-brain structure in patients with schizophrenia. METHODS: Participants were 65 patients diagnosed with schizophrenia (mean age: 37.2 ± 11.3 years, 32 females). All participants were Japanese and right-handed. Symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS) and Pittsburgh Sleep Quality Index (PSQI). Voxel based morphometry (VBM) and diffusion tensor imaging (DTI) were performed to analyze the association of obesity with gray and white matter structures, respectively. RESULTS: There was no significant difference in PANSS scores between obese and non-obese patients, while the PSQI score was significantly higher in the former than in the latter (p < 0.05). The daily dose of typical antipsychotics was significantly higher in obese patients than in non-obese patients (p < 0.001). In VBM, there was no significant difference in gray matter volume between obese and non-obese patients. In DTI, fractional anisotropy values in the corpus callosum, corona radiata, corticospinal tract, superior longitudinal fasciculus, and posterior thalamic radiations were significantly lower in obese patients than in non-obese patients (corrected p < 0.05). Axial diffusivity was significantly lower while radial and mean diffusivities values were significantly higher in obese patients than in non-obese patients (corrected p < 0.05) in similar but more restricted brain regions. CONCLUSION: Our results suggest that obesity is related to sleep disturbances, daily dose of typical antipsychotics, and regional white matter microstructure impairments in patients with schizophrenia.

Corrigendum: Correlation Between the Wechsler Adult Intelligence Scale- 3 rd Edition Metrics and Brain Structure in Healthy Individuals: A Whole-Brain Magnetic Resonance Imaging Study.

[This corrects the article DOI: 10.3389/fnhum.2020.00211.].

Correlation Between the Wechsler Adult Intelligence Scale- 3 rd Edition Metrics and Brain Structure in Healthy Individuals: A Whole-Brain Magnetic Resonance Imaging Study.

BACKGROUND: The Wechsler Adult Intelligence Scale, 3rd edition (WAIS-III) is widely used to evaluate the intelligence quotient (IQ). We aimed to investigate the correlation between the WAIS-III metrics and whole-brain structures using magnetic resonance imaging. METHODS: The participants were 266 healthy, right-handed individuals (age: 45.6 ± 12.9 years, 98 males and 168 females). IQs were evaluated using the WAIS-III and Japanese Adult Reading Test (JART). Voxel-based morphometry and diffusion tensor imaging were performed to analyze the correlation of the WAIS-III metrics and JART score with the gray matter volume and white matter integrity, respectively. RESULTS: The verbal IQ significantly and positively correlated with the left gyrus rectus and anterior cingulate gyrus, left posterior insula and planum polare, and left superior and middle frontal gyri volumes (p < 0.05, corrected). The verbal comprehension group index significantly and positively correlated with the left superior and middle frontal gyri, left gyrus rectus and anterior cingulate gyrus, and left middle frontal gyrus volumes, while the processing speed group index significantly and positively correlated with the bilateral various regional white matter fractional anisotropy values (p < 0.05, corrected). In contrast, the JART score showed no correlation with any brain structure. CONCLUSION: These results suggested the neurostructural bases of the WAIS-III IQs and group indices in the brain of healthy individuals.

The Neural Basis of Changing Social Norms through Persuasion.

Social norms regulate behavior, and changes in norms have a great impact on society. In most modern societies, norms change through interpersonal communication and persuasive messages found in media. Here, we examined the neural basis of persuasion-induced changes in attitude toward and away from norms using fMRI. We measured brain activity while human participants were exposed to persuasive messages directed toward specific norms. Persuasion directed toward social norms specifically activated a set of brain regions including temporal poles, temporo-parietal junction, and medial prefrontal cortex. Beyond these regions, when successful, persuasion away from an accepted norm specifically recruited the left middle temporal and supramarginal gyri. Furthermore, in combination with data from a separate attitude-rating task, we found that left supramarginal gyrus activity represented participant attitude toward norms and tracked the persuasion-induced attitude changes that were away from agreement.

Regional gray matter volume in the posterior precuneus is associated with general self-efficacy.

Motivation in doing a task is influenced not only by the expected outcome of the task but also by the belief that one has in successfully executing the task. Over time, individuals accumulate experiences that contribute toward a general belief in one's overall ability to successfully perform tasks, which is called general self-efficacy (GSE). We investigated the relationship between regional gray matter volume and individual differences in GSE. Brain anatomy was analyzed using magnetic resonance images obtained from 64 healthy right-handed participants who had completed Sherer's GSE scale. After controlling for other factors related to motivation, age, sex, and total gray matter volume of each participant, results showed that regional gray matter volume in the posterior part of the precuneus significantly and positively correlated with the GSE score. These results suggest that one's accumulated experiences of success and failure, which contribute toward GSE, also influence the anatomical characteristics of the precuneus.

The neural basis of the imitation drive.

Spontaneous imitation is assumed to underlie the acquisition of important skills by infants, including language and social interaction. In this study, functional magnetic resonance imaging (fMRI) was used to examine the neural basis of 'spontaneously' driven imitation, which has not yet been fully investigated. Healthy participants were presented with movie clips of meaningless bimanual actions and instructed to observe and imitate them during an fMRI scan. The participants were subsequently shown the movie clips again and asked to evaluate the strength of their 'urge to imitate' (Urge) for each action. We searched for cortical areas where the degree of activation positively correlated with Urge scores; significant positive correlations were observed in the right supplementary motor area (SMA) and bilateral midcingulate cortex (MCC) under the imitation condition. These areas were not explained by explicit reasons for imitation or the kinematic characteristics of the actions. Previous studies performed in monkeys and humans have implicated the SMA and MCC/caudal cingulate zone in voluntary actions. This study also confirmed the functional connectivity between Urge and imitation performance using a psychophysiological interaction analysis. Thus, our findings reveal the critical neural components that underlie spontaneous imitation and provide possible reasons why infants imitate spontaneously.

Coordinated activation of premotor and ventromedial prefrontal cortices during vicarious reward.

The vicarious reward we receive from watching likable others obtaining a positive outcome is a pervasive phenomenon, yet its neural correlates are poorly understood. Here, we conducted a series of functional magnetic resonance imaging experiments to test the hypothesis that the brain areas responsible for action observation and reward processing work in a coordinated fashion during vicarious reward. In the first experiment (manipulation phase), the participant was instructed to cheer for a particular player in a two-player competitive game (Rock-Paper-Scissors). This manipulation made participants feel more unity with that player and resulted in unity-related activation in the premotor area during action observation. In the following main experiment, the participant witnessed the previously cheered-for or non-cheered-for player succeed in a new solitary game (a stopwatch game). The ventromedial prefrontal cortex (vmPFC) was activated when the cheered-for player succeeded in the game but not when the other player did. Interestingly, this vmPFC activation was functionally connected with premotor activation only during the cheered-for player's success. These results suggest that vicarious reward is processed in the vmPFC-premotor network, which is activated specifically by the success of the other person with whom the individual feels unity and closeness.

The neural bases for valuing social equality.

The neural basis of how humans value and pursue social equality has become a major topic in social neuroscience research. Although recent studies have identified a set of brain regions and possible mechanisms that are involved in the neural processing of equality of outcome between individuals, how the human brain processes equality of opportunity remains unknown. In this review article, first we describe the importance of the distinction between equality of outcome and equality of opportunity, which has been emphasized in philosophy and economics. Next, we discuss possible approaches for empirical characterization of human valuation of equality of opportunity vs. equality of outcome. Understanding how these two concepts are distinct and interact with each other may provide a better explanation of complex human behaviors concerning fairness and social equality.

Adaptive ability to cope with atypical or novel situations involving tool use: an fMRI approach.

We investigated the neural mechanisms underlying the ability to cope in atypical or novel situations using tools. We hypothesized that two cognitive components support this ability: adaptive coordination (for adapting to situational demands) and cognitive inhibition (for inhibiting the incongruent actions afforded by tools). We had subjects choose novel tools for a given task or choose among familiar tools in an atypical situation, during which we examined cortical activation in their brains using functional magnetic resonance imaging. Neural activation during adaptive coordination was observed in the left lateral orbitofrontal cortex, inferior frontal gyrus and sulcus, middle and medial frontal gyrus, intraparietal sulcus, precentral sulcus, inferior temporal gyrus, supramarginal gyrus, the bilateral insula, anterior cingulate cortex, and the right callosal sulcus. Activation indicating cognitive inhibition was observed in the right middle and inferior frontal gyrus. These findings demonstrate that the left parietal region shapes basic action, whereas the right frontal region inhibits stereotypical action. The left frontal regions are thought to be linked to the processing of ambiguous actions and play key roles in coordinating actions, whereas other regions are involved in processing situational contexts. Our results may be important for understanding the neural systems underlying adaptability to daily social situations.

Neural Mechanism for Mirrored Self-face Recognition.

Self-face recognition in the mirror is considered to involve multiple processes that integrate 2 perceptual cues: temporal contingency of the visual feedback on one's action (contingency cue) and matching with self-face representation in long-term memory (figurative cue). The aim of this study was to examine the neural bases of these processes by manipulating 2 perceptual cues using a "virtual mirror" system. This system allowed online dynamic presentations of real-time and delayed self- or other facial actions. Perception-level processes were identified as responses to only a single perceptual cue. The effect of the contingency cue was identified in the cuneus. The regions sensitive to the figurative cue were subdivided by the response to a static self-face, which was identified in the right temporal, parietal, and frontal regions, but not in the bilateral occipitoparietal regions. Semantic- or integration-level processes, including amodal self-representation and belief validation, which allow modality-independent self-recognition and the resolution of potential conflicts between perceptual cues, respectively, were identified in distinct regions in the right frontal and insular cortices. The results are supportive of the multicomponent notion of self-recognition and suggest a critical role for contingency detection in the co-emergence of self-recognition and empathy in infants.

Social equality in the number of choice options is represented in the ventromedial prefrontal cortex.

A distinct aspect of the sense of fairness in humans is that we care not only about equality in material rewards but also about equality in nonmaterial values. One such value is the opportunity to choose freely among many options, often regarded as a fundamental right to economic freedom. In modern developed societies, equal opportunities in work, living, and lifestyle are enforced by antidiscrimination laws. Despite the widespread endorsement of equal opportunity, no studies have explored how people assign value to it. We used functional magnetic resonance imaging to identify the neural substrates for subjective valuation of equality in choice opportunity. Participants performed a two-person choice task in which the number of choices available was varied across trials independently of choice outcomes. By using this procedure, we manipulated the degree of equality in choice opportunity between players and dissociated it from the value of reward outcomes and their equality. We found that activation in the ventromedial prefrontal cortex (vmPFC) tracked the degree to which the number of options between the two players was equal. In contrast, activation in the ventral striatum tracked the number of options available to participants themselves but not the equality between players. Our results demonstrate that the vmPFC, a key brain region previously implicated in the processing of social values, is also involved in valuation of equality in choice opportunity between individuals. These findings may provide valuable insight into the human ability to value equal opportunity, a characteristic long emphasized in politics, economics, and philosophy.

The neural basis of event simulation: an FMRI study.

Event simulation (ES) is the situational inference process in which perceived event features such as objects, agents, and actions are associated in the brain to represent the whole situation. ES provides a common basis for various cognitive processes, such as perceptual prediction, situational understanding/prediction, and social cognition (such as mentalizing/trait inference). Here, functional magnetic resonance imaging was used to elucidate the neural substrates underlying important subdivisions within ES. First, the study investigated whether ES depends on different neural substrates when it is conducted explicitly and implicitly. Second, the existence of neural substrates specific to the future-prediction component of ES was assessed. Subjects were shown contextually related object pictures implying a situation and performed several picture-word-matching tasks. By varying task goals, subjects were made to infer the implied situation implicitly/explicitly or predict the future consequence of that situation. The results indicate that, whereas implicit ES activated the lateral prefrontal cortex and medial/lateral parietal cortex, explicit ES activated the medial prefrontal cortex, posterior cingulate cortex, and medial/lateral temporal cortex. Additionally, the left temporoparietal junction plays an important role in the future-prediction component of ES. These findings enrich our understanding of the neural substrates of the implicit/explicit/predictive aspects of ES-related cognitive processes.

The neural bases underlying social risk perception in purchase decisions.

Social considerations significantly influence daily purchase decisions, and the perception of social risk (i.e., the anticipated disapproval of others) is crucial in dissuading consumers from making purchases. However, the neural basis for consumers' perception of social risk remains undiscovered, and this novel study clarifies the relevant neural processes. A total of 26 volunteers were scanned while they evaluated purchase intention of products (purchase intention task) and their anticipation of others' disapproval for possessing a product (social risk task), using functional magnetic resonance imaging (fMRI). The fMRI data from the purchase intention task was used to identify the brain region associated with perception of social risk during purchase decision making by using subjective social risk ratings for a parametric modulation analysis. Furthermore, we aimed to explore if there was a difference between participants' purchase decisions and their explicit evaluations of social risk, with reference to the neural activity associated with social risk perception. For this, subjective social risk ratings were used for a parametric modulation analysis on fMRI data from the social risk task. Analysis of the purchase intention task revealed a significant positive correlation between ratings of social risk and activity in the anterior insula, an area of the brain that is known as part of the emotion-related network. Analysis of the social risk task revealed a significant positive correlation between ratings of social risk and activity in the temporal parietal junction and the medial prefrontal cortex, which are known as theory-of-mind regions. Our results suggest that the anterior insula processes consumers' social risk implicitly to prompt consumers not to buy socially unacceptable products, whereas ToM-related regions process such risk explicitly in considering the anticipated disapproval of others. These findings may prove helpful in understanding the mental processes involved in purchase decisions.