Published papers

Our thought states shift from one state to another from moment to moment. The relationship between the thought shifting and bodily responses is yet to be directly examined. This exploratory study examined the influence of cardiovascular reactivity and interoception-sensing an internal bodily state-on the shifting of thought states. Participants (N = 100, 70 women) completed two tasks: the heartbeat counting task (HCT) and the vigilance task (VT). We assessed their interoceptive accuracy through their performance on the HCT. The VT was a simple sustained attention task in which participants pressed a key when the target stimulus appeared and were asked to report their thoughts. We presented subliminal vibration stimuli to induce alterations in heart rate (i.e., vibration block). Results showed that participants with higher interoceptive accuracy reported more continuation of self-referential thought (about past episodes and future plans regarding themselves) during the vibration block than did those with lower interoceptive accuracy. These results suggest that individuals with higher interoceptive accuracy are more likely to be influenced by their subliminal bodily response, resulting in divergent attention from the task and intermittent self-referential thought.

CONTEXT: Epidemiological studies have shown that consumption of dairy products reduces the risk of dementia and cognitive decline in older individuals. Tryptophan-tyrosine-related β-lactopeptides and their representative β-lactolin of glycine-threonine-tryptophan-tyrosine tetra-peptide have been identified as agents in dairy products, which improve cognitive function as well as memory function via the activation of the dopaminergic system in a mouse model of amnesia. Previous clinical trials have shown that supplementation with β-lactolin improves memory retrieval in healthy older adults. Specifically, β-lactolin improved the scores in some neuropsychological tests. However, the effects of β-lactolin on memory function have not been clarified. OBJECTIVES: The aim of this study was to evaluate the effect of β-lactolin on memory function using statistical methods. DATA SOURCES: We searched the Web of Science, Cochrane Library, and JDream III until November 2021 to identify relevant randomized controlled trials for integrated analysis. DATA SYNTHESIS: Three randomized controlled trials evaluating the effect of β-lactolin on memory in healthy adults were selected for the integrated analysis. The results showed that the score of cued recall among the neuropsychological tests in the β-lactolin group was significantly higher than that in the placebo group (g=0.33; 95% CI: 0.10, 0.55). In addition, the total memory score was higher but this difference was not significant (g=0.17; 95% CI: -0.09, 0.43). CONCLUSIONS: Taken together, these results suggest that supplementation with β-lactolin improves cued recall in healthy older adults.

Cognitive behavioral therapy (CBT) and pharmacotherapy are primary treatments for major depressive disorder (MDD). However, their differential effects on the neural networks associated with rumination, or repetitive negative thinking, remain poorly understood. This study included 135 participants, whose rumination severity was measured using the rumination response scale (RRS) and whose resting brain activity was measured using functional magnetic resonance imaging (fMRI) at baseline and after 16 weeks. MDD patients received either standard CBT based on Beck's manual (n = 28) or pharmacotherapy (n = 32). Using a hidden Markov model, we observed that MDD patients exhibited increased activity in the default mode network (DMN) and decreased occupancies in the sensorimotor and central executive networks (CEN). The DMN occurrence rate correlated positively with rumination severity. CBT, while not specifically designed to target rumination, reduced DMN occurrence rate and facilitated transitions toward a CEN-dominant brain state as part of broader therapeutic effects. Pharmacotherapy shifted DMN activity to the posterior region of the brain. These findings suggest that CBT and pharmacotherapy modulate brain network dynamics related to rumination through distinct therapeutic pathways.

Studies in psychiatry and cognitive neuroscience have reported an important relationship between individual interoceptive accuracy and anxiety level. This indicates that greater attention to one's bodily state may contribute to the development of intense negative emotions and anxiety disorders. We hypothesized that reactivity in the anterior insular cortex underlies the intensity of interoceptive awareness and anxiety. To elucidate this triadic mechanism, we conducted functional magnetic resonance imaging (fMRI) and mediation analyses to examine the relationship between emotional disposition and activation in the anterior insular cortex while participants evaluated their own emotional and bodily states. Our results indicated that right anterior insular activation was positively correlated with individual levels of social anxiety and neuroticism and negatively correlated with agreeableness and extraversion. The results of the mediation analyses revealed that activity in the right anterior insula mediated the activity of neural correlates of interoceptive sensibility and social fear. Our findings suggest that attention to interoceptive sensation affects personality traits through how we feel emotion subjectively in various situations. © The Author (2012). Published by Oxford University Press.

Neuropsychological investigations of prospective memory (PM), representing memory of future intentions or plans, have evolved over the past two decades. The broadly accepted divisions involved in PM consist of a prospective memory component (PMC), a process for remembering to remember, and a retrospective memory component, a process for remembering the content of the intended action. Previous functional neuroimaing studies have provided some evidence that the rostral prefrontal cortex (BA10) is one of areas that is critical for prospective remembering. However, the question of whether damage to part of the prefrontal cortex affects attenuated performance for PMC remains unresolved. In this study, 74 participants with traumatic brain injury (TBI) including focal damage to frontal or temporal lobe areas were administered thirteen standard neuropsychological tests and the PM task. To identify influential areas contributing to PM performance, discriminant function analysis was conducted. The results indicated that the following three areas are highly contributory to PM performance: the right dorsolateral prefrontal cortex; the right ventromedial prefrontal cortex; and the left dorsomedial prefrontal cortex. Comparing differences in neuropsychological test scores showed that orientation scores were significantly higher in the greater PM performance group, suggesting that PMC represents an integrated memory function associated with awareness of current status. These data contribute to our understanding of the neural substrates and functional characteristics of the PMC. © 2011 Elsevier Ltd.

Physiological bodily states play an important role in affective experiences. This study investigated whether the neural processing of internal body state (interoception) is associated with empathy, the understanding of the affective states of others. We used the 'heartbeat-evoked potential' (HEP), a surface electroencephalography (EEG) pattern, as a neural index of interoceptive processing. The HEP is contingent on the most prominent peak (R-wave) of the electrocardiogram (ECG) and is thought to reflect cortical processing of cardiac afferent input. Twenty-one healthy adults performed empathy and control tasks while EEG and ECG were recorded, where they made judgments based on either the affective or physical aspects of images of human eyes. HEP, ECG and heart rate in each task block were calculated and compared. Results showed that cardiac activity was not significantly different between tasks. In contrast, HEP showed a significant task difference, exhibited as an increased negativity during the empathy task over frontocentral sites at a latency of approximately 250-430. ms. Furthermore, a self-reported measure of empathy was associated with mean HEP amplitude during the period of task-related differentiation. These results suggest that afferent feedback from visceral activity may contribute to inferences about the affective state of others. © 2010 Elsevier B.V.

Given the results of studies using the Iowa Gambling Task (IGT), emotion-based sensitivity to an anticipated outcome of one's own behavior has been suggested to be a significant factor in making advantageous decisions. Hypotheses-testing in performing IGT is essential for learning correct rules and elicits autonomic reactivity. In this study, participants were asked to concentrate on hypothesis-testing to learn undisclosed rules in the task which framework was similar to the IGT, rather than maximizing monetary reward. The amplitudes of skin conductance responses (SCRs) prior to card selection and following feedback were attenuated as participants came to accurately comprehend the task rules. The attenuation of SCRs resulted from reduced motivation to continue the hypotheses-testing. Our findings provide some evidence that observed autonomic responses partially reflect emotional reactions associated with the hypothesis-testing.

Recent neuroimaging studies on "theory of mind" have demonstrated that the medial prefrontal cortex (PFC) is involved when subjects are engaged in various kinds of mentalising tasks. Although a large number of neuroimaging studies have been published, a relatively small amount of neuropsychological evidence supports involvement of the medial PFC in theory of mind reasoning. We recruited two neurological cases with damage to the medial PFC and initially performed the standard neuropsychological assessments for intelligence, memory, and executive functions. To examine theory of mind performance in these two cases, four kinds of standard and advanced tests for theory of mind were used, including first- and second-order false belief tests, the strange stories test, and the faux pas recognition test. Both patients were also requested to complete the questionnaire for the autism-spectrum quotient. Neither case showed impairment on standard theory of mind tests and only mild impairments were seen on advanced theory of mind tests. This pattern of results is basically consistent with previous studies. The most interesting finding was that both cases showed personality changes after surgical operations, leading to characteristics of autism showing a lack of social interaction in everyday life. We discuss herein the possible roles of the medial PFC and emphasize the importance of using multiple approaches to understand the mechanisms of theory of mind and medial prefrontal functions. © 2009 Psychology Press.

Background: Heavy alcohol intake induces both structural and functional changes in the central nervous system. Recent research developments converged on the idea that even in patients with alcohol dependence without apparent structural brain changes, some cognitive impairment exists, and associated functional change could be visualized by neuroimaging techniques. However, these data were from old (more than 50 years) patients using working memory and response inhibition tasks. Whether young abstinent patients show aberrant signs of brain activation is a matter of interest, specifically by the long-term memory retrieval task. Methods: Subjects were 9 young patients with alcohol dependence with long-term abstinent (8 males and 1 female) and age- and education-matched 9 healthy controls (7 males and 2 females). We used a modified false recognition task in a functional MRI study. Results: The young patients with alcohol dependence showed reduced activation in the right dorsolateral prefrontal cortex, anterior cingulate cortex (ACC), left pulvinar in the thalamus, and in the right ventral striatum, although behavioral performances and regional patterns of brain activation were similar between patients and controls. Conclusions: Long-term memory retrieval induced altered activations in prefrontal lobes, ACC, thalamus, and ventral striatum in young patients with alcohol dependence. These findings were correspondent to deficits of goal directed behavior, monitoring the erroneous responses, memory function, and drug-seeking behavior. Furthermore, these reduced activations can be considered as latent "lesions," suggesting subclinical pathology in alcoholic brains. © 2007 by the Research Society on Alcoholism.

© 2019 Elsevier B.V. The factors that determine the content and valence of spontaneous thoughts have not yet been clarified. In this study, we focused on the effects of bodily states and depression and anxiety traits. Participants performed a past/future thinking task in which three-part sentences including temporal cues were presented in a sequential pattern, for example “in the near future/dreams/will come true”. We measured heartbeat-evoked potentials (HEPs)to assess affective processing, and event-related potentials (ERPs)to assess temporal processing of thoughts that emerged when the temporal cue words were presented. The HEPs predicted thought valence irrespective of personality traits. Larger N400 ERPs were observed in response to past-oriented than to future-oriented words in participants with higher levels of depression, whereas the opposite was the case in participants with higher social anxiety. Our data suggest that afferent signals modulate affective thought-orientations as triggers, and that individuals with depression and anxiety have sensitivity toward temporal information at the neural level.

The majority of the models of emotional processing attribute subjective emotional feelings to physiological changes in the internal milieu, which are sensed by the interoceptive system. These physiological reactions evoked by emotional phenomena occur via the autonomic nervous system, and give rise to alterations in body-mind interactions that are characterized by heartbeat evoked magnetic fields (HEFs) involving brain regions associated with emotional perception. The current study used magnetoencephalography (MEG) to examine regional cortical activity and connectivity changes in HEFs provoked by the emotion of disgust. MEG results from 39 healthy subjects (22 female) revealed that passively listening to sounds of disgust elicited right insular cortical activity and enhancement of cortical connectivity between the right anterior ventral insular cortex and left ventromedial prefrontal cortex, demonstrated by phase lag indexes in the beta frequency range. Furthermore, inter-trial coherence significantly increased at 19 Hz and 23 Hz, and decreased at 14 Hz, which highlights the involvement of low beta oscillations in emotional processing. As these results were based on spontaneously triggered bioelectrical signals, more indigenous and induced signals were extracted with a block designed experiment. The insular cortices play an important role in emotional regulation and perception as the main cortical target for signals with interoceptive information, providing direct substrates of emotional feelings. The current results provide a novel insight into frequency properties of emotional processing, and suggest that emotional arousal evoked by listening to sounds of disgust partially impact the autonomic nervous system, altering HEFs via connectivity changes in the right anterior ventral insular cortex and left ventromedial prefrontal cortex.

With the objective to investigate the role of the insula in recognizing emotion, we performed direct electrical stimulation over the anterior insular cortex during awake surgery while simultaneously delivering an emotional sensitivity task. We registered 18 consecutive patients with brain tumors associated with the insular lobe, who were undergoing tumor resection. An emotional sensitivity task was employed to measure the patients' ability to recognize emotions from facial expressions before, during, and after awake surgery. Furthermore, we performed voxel-based lesion symptom mapping (VLSM) to identify the association between relevant brain lesions and emotion recognition. When we performed direct electrical stimulation over the anterior insular cortex during awake surgery, the results showed that the ability to recognize anger was significantly enhanced with the presence of anterior insular stimulation (p < 0.05). Comparing the performance in the emotional sensitivity task before and after surgery, the performance in the anger condition became worse (p < 0.01), but became better in the sadness condition after surgery (p < 0.01). In the case of anger recognition, lower scores in the correct response index were associated with lesions involving the left insula in the VLSM study. Direct electrical stimulation over the anterior insular cortex enhanced anger recognition in patients with insular tumors. In contrast, accuracy of anger recognition was significantly reduced, and sadness was improved, when the performance of emotional sensitivity was compared pre- and post-surgery. Our findings suggest that the insular cortex is involved in changes in emotion recognition, including anger and sadness recognition by modulating arousal level that is closely connected with interoception.

Some studies have asked participants about attentional state on a scale from on-task to off-task, which set the middle option as attention focused on both, including the possibility of the coexistence of thoughts. In addition, studies using multidimensional probes explicitly assumed coexistence within spontaneous thoughts and task-focus dimensions. Although several studies have assumed the coexistence of some thought dimensions, none has explored whether these are different types of thoughts (task-focus, mind-wandering, task-related, external stimuli-related). To examine whether this coexistence of thought types occurred, we used thought probes to determine the degree of immersion in each. The participants responded to probes presented at random during a sustained attention task. The results revealed a mixture of thought types in many self-reports. In addition, the state of attentional allocation behind self-reports was estimated using the hidden Markov model. We observed the following attentional states: task-focused, task-unrelated, task-related, external stimuli-focused, and task-focused-but also focused on other thoughts. These results suggest that individuals can simultaneously allocate attention to thought types and discriminate between reporting. In some cases, probe options should also be considered for this coexistence. We also examined the relationship between self-reports and behavioral indexes, and discussed the necessity of separately measuring the degree of immersion for each thought type.

Background: Despite the importance of Beck's theoretical cognitive model of psychopathology, the neural mechanisms underlying future thinking in cognitive behavioral therapy (CBT) remain elusive. Recent neuroimaging studies have shown that the function of the frontopolar cortex (Brodmann area 10 [BA10]) is associated with future thinking. We hypothesized that, compared with unstructured psychotherapy (talking control: TC), CBT may involve different neural responses in BA10 associated with future thinking. Methods: This randomized clinical trial included 38 adult patients with moderate-to-severe major depressive disorder who underwent up to 16 weeks of CBT or TC with a 6-month follow-up period. We evaluated changes in BA10 activation during distant future thinking using functional magnetic resonance imaging with a future-thinking task. We assessed frontal neurocognitive function and clinical symptoms at baseline and post-treatment. Depression severity and automatic thoughts were assessed at the 6-month follow-up. Results: We found decreased activation in the frontopolar cortex during distant future thinking after CBT (t = 3.00, df=15, p = 0.009) and no changes after TC. Further, the reduction in BA10 activity significantly correlated with changes in frontal cognitive function after the treatment (r = 0.48, p = 0.007), and in positive automatic thought after 6 months of treatments (r = 0.39; p = 0.03). Limitations: Relatively small sample size and homogenous clinical profile could limit the generalizability. Patients received pharmacotherapy including antidepressant. Conclusions: CBT appears to improve frontopolar cortex function during future thinking in a manner distinct from TC. Larger clinical trials are necessary to provide firm evidence whether BA10 activity may serve as a neuro-marker for monitoring successful depression treatment with CBT.