Makoto Miyakoshi

Associations among positive mood, brain, and cardiovascular activities in an affectively positive situation.

It is hypothesized that experiencing positive emotions such as pleasure leads to a perception of the body being in a positive state. This study demonstrated associations among positive mood, brain, and cardiovascular activities by simultaneously recording these activities when positive emotions were evoked in participants watching films revolving around a love story. Heart rate variability analysis revealed increased parasympathetic nervous activity while watching the film. The following brain regions were significantly activated in the positive condition relative to the control condition: medial prefrontal cortex, thalamus, superior temporal gyrus, inferior frontal gyrus, and cerebellum. Further, covariate analyses indicated that these brain regions were temporally associated with subjective positive mood. Activities of brain regions considered to be related to interoceptive awareness, such as the insular cortex, anterior cingulate cortex, amygdala, and orbitofrontal cortex, were also temporally associated with the cardiovascular change. These results suggest that while an individual experiences positive emotions, activities of the central nervous system and cardiovascular system may be interrelated, and the brain may perceive the body to be in a positive state.

Imaging brain and immune association accompanying cognitive appraisal of an acute stressor.

Acute stress elicits multiple responses in autonomic, endocrine, and immune systems. Cognitive appraisal is believed to be one important modulator of such stress responses. To investigate brain substrates of crosstalks between the homeostasis-maintaining systems accompanying appraisal of stressor controllability, we simultaneously recorded regional cerebral blood flow (rCBF) using 15O-water positron emission tomography, cardiovascular indices (heart rate (HR) and blood pressure (BP)), neuroendocrine indices (concentrations of epinephrine, norepinephrine, and adrenocorticotropic hormone (ACTH) in blood), and immune indices (proportions of subsets of lymphocytes (NK cells, helper T cells, cytotoxic T cells, and B cells) in blood), in 11 male subjects who performed a mental arithmetic task with either high controllability (HC) and low controllability (LC). The LC task resulted in less sense of control in subjects than the HC task. Significant increases of rCBF in the medial and lateral orbitofrontal cortices (OFC), and in the medial and lateral prefrontal cortices (MPFC, LPFC) were observed by subtracting the HC task from the LC task. More importantly, significant positive correlations between rCBF and HR, BP, and NK cells were commonly found in the OFC and MPFC during the LC tasks, but not during the HC tasks. The present results showed for the first time that the prefrontal neural network including the OFC and MPFC might be one pivotal region for bi-directional functional association between the brain and peripheral autonomic and immune activities accompanying appraisal of an acute stressor.

EEG evidence of face-specific visual self-representation

Cognitive science has regarded an individuals face as a form of representative stimuli to engage self-representation. The domain-generality of self-representation has been assumed in several reports, but was recently refuted in a functional magnetic resonance imaging study (Sugiura et al., 2008). The general validity of this studys criticism should be tested by other measures to compensate for the limitation of the time resolution of the blood-oxygen-level-dependent (BOLD) signal. In this article, we report an EEG study on the domain-generality of visual self-representation. Domain-general self-representation was operationally defined as the self-relevance common to ones own Face and Cup; three levels of familiarity, Self, Familiar, and Unfamiliar, were prepared for each. There was another condition, Visual Field, that manipulated visual hemifield during stimulus presentation, but it was collapsed because it produced no interaction with stimulus familiarity. Our results confirmed comparable phase resetting in both domains in response to familiarity manipulation, which occurred within the medial frontal area during 270-390 ms poststimulus and in the theta band. However, self-specific dissociation was observed only for Face. The results here support the conclusion that visual self-representation is domain-specific and that the oscillatory responses observed suggest evidence of face-specific visual self-representation. Results also revealed an inter-trial phase coherency decrease specifically for Self-Face within the right fusiform area during 170-290 ms poststimulus and in the alpha and theta band, suggesting reduced functional demand for Self-Face represented by sharpened networks.

Cortical substrates and functional correlates of auditory deviance processing deficits in schizophrenia

Although sensory processing abnormalities contribute to widespread cognitive and psychosocial impairments in schizophrenia (SZ) patients, scalp-channel measures of averaged event-related potentials (ERPs) mix contributions from distinct cortical source-area generators, diluting the functional relevance of channel-based ERP measures. SZ patients (n = 42) and non-psychiatric comparison subjects (n = 47) participated in a passive auditory duration oddball paradigm, eliciting a triphasic (Deviant−Standard) tone ERP difference complex, here termed the auditory deviance response (ADR), comprised of a mid-frontal mismatch negativity (MMN), P3a positivity, and re-orienting negativity (RON) peak sequence. To identify its cortical sources and to assess possible relationships between their response contributions and clinical SZ measures, we applied independent component analysis to the continuous 68-channel EEG data and clustered the resulting independent components (ICs) across subjects on spectral, ERP, and topographic similarities. Six IC clusters centered in right superior temporal, right inferior frontal, ventral mid-cingulate, anterior cingulate, medial orbitofrontal, and dorsal mid-cingulate cortex each made triphasic response contributions. Although correlations between measures of SZ clinical, cognitive, and psychosocial functioning and standard (Fz) scalp-channel ADR peak measures were weak or absent, for at least four IC clusters one or more significant correlations emerged. In particular, differences in MMN peak amplitude in the right superior temporal IC cluster accounted for 48% of the variance in SZ-subject performance on tasks necessary for real-world functioning and medial orbitofrontal cluster P3a amplitude accounted for 40%/54% of SZ-subject variance in positive/negative symptoms. Thus, source-resolved auditory deviance response measures including MMN may be highly sensitive to SZ clinical, cognitive, and functional characteristics.

White matter connectivity between superior temporal sulcus and amygdala is associated with autistic trait in healthy humans.

Growing evidence suggests that autistic traits, such as reduced social and communication skills, exist along a continuum between healthy and pathological conditions. Thus, functional and structural investigations of neuroanatomical substrates that significantly correlate with autistic tendency in healthy human subjects are critical for understanding this disorder. To accomplish this goal, we performed functional magnetic resonance imaging (fMRI) in combination with diffusion tensor imaging (DTI) in 30 healthy young subjects. The subjects were evaluated using the Autistic-Spectrum Quotient (AQ), which was designed to measure autistic traits in healthy and autistic spectrum disorder (ASD) subjects. Face-specific brain activation in the superior temporal sulcus (STS) and amygdala (AMG) was identified using fMRI and passive viewing of faces. In addition, probabilistic tractography performed in each subject by using DTI showed a white matter pathway between the face-specific regions of interest in the STS and AMG. The volume of connectivity between the STS and AMG correlated positively with the total AQ score (Spearmans ρ=0.38, p<0.05); however, among the AQ subscales, only imagination was significantly associated with the connectivity volume. These results suggest that healthy subjects with high autistic traits may show an increase in the white matter pathway that connects key regions involved in face processing.

ERP study of viewpoint-independence in familiar-face recognition.

While faces are recognized viewpoint-dependently, familiar faces are recognized in a relatively viewpoint-independent manner. We conducted a cognitive ERP experiment to investigate the effect of viewpoint-independence for familiar-face recognition. The present results showed that facial angle differences were reflected by N170 latency and N250 amplitude. Furthermore, the N250 difference was attenuated in the left hemisphere for famous faces and in the right hemisphere for ones own face. We concluded that familiar faces are first recognized viewpoint-dependently, but then are represented viewpoint-independently. The laterality difference observed in N250 may be related to a self-relevant process in the right hemisphere, while a familiarity process is associated with the left hemisphere.

Interictal high-frequency oscillations generated by seizure onset and eloquent areas may be differentially coupled with different slow waves

OBJECTIVE High-frequency oscillations (HFOs) can be spontaneously generated by seizure-onset and functionally-important areas. We determined if consideration of the spectral frequency bands of coupled slow-waves could distinguish between epileptogenic and physiological HFOs. METHODS We studied a consecutive series of 13 children with focal epilepsy who underwent extraoperative electrocorticography. We measured the occurrence rate of HFOs during slow-wave sleep at each electrode site. We subsequently determined the performance of HFO rate for localization of seizure-onset sites and undesirable detection of nonepileptic sensorimotor-visual sites defined by neurostimulation. We likewise determined the predictive performance of modulation index: MI(XHz)&(YHz), reflecting the strength of coupling between amplitude of HFOsXHz and phase of slow-waveYHz. The predictive accuracy was quantified using the area under the curve (AUC) on receiver-operating characteristics analysis. RESULTS Increase in HFO rate localized seizure-onset sites (AUC⩾0.72; p<0.001), but also undesirably detected nonepileptic sensorimotor-visual sites (AUC⩾0.58; p<0.001). Increase in MI(HFOs)&(3-4Hz) also detected both seizure-onset (AUC⩾0.74; p<0.001) and nonepileptic sensorimotor-visual sites (AUC⩾0.59; p<0.001). Increase in subtraction-MIHFOs [defined as subtraction of MI(HFOs)&(0.5-1Hz) from MI(HFOs)&(3-4Hz)] localized seizure-onset sites (AUC⩾0.71; p<0.001), but rather avoided detection of nonepileptic sensorimotor-visual sites (AUC⩽0.42; p<0.001). CONCLUSION Our data suggest that epileptogenic HFOs may be coupled with slow-wave3-4Hz more preferentially than slow-wave0.5-1Hz, whereas physiologic HFOs with slow-wave0.5-1Hz more preferentially than slow-wave3-4Hz during slow-wave sleep. SIGNIFICANCE Further studies in larger samples are warranted to determine if consideration of the spectral frequency bands of slow-waves coupled with HFOs can positively contribute to presurgical evaluation of patients with focal epilepsy.

Hierarchical Event Descriptor (HED) tags for analysis of event-related EEG studies

Data from well-designed EEG experiments should find uses beyond initial reports, even when study authors cannot anticipate how it may contribute to future analyses. Several ontologies have been proposed for describing events in cognitive experiments to make data available for re-use and meta-analysis, but none are widely used. One reason for this is that the tools needed to make use of these ontologies are complex, placing a significant burden on experimenters while not providing any immediate reward for their efforts. Here we propose an extensible, user-friendly experiment event tagging method built on the BrainMap and CogPO ontologies and similar to the object tagging style used extensively on the Web. Hierarchical Event Descriptor (HED) tags, a hierarchy of standard and extended descriptors for EEG experimental events, provide a uniform human- and machine-readable interface facilitating use of an underlying event-description ontology during EEG data acquisition, analysis, and sharing. HED tags may be used to mark and annotate all known events in an experimental session. We describe an available real-time EEG experiment control and recording system that uses HED tags for annotation, transmission and storage of detailed information about events in EEG experiments.

Sex, Impulsivity, and Anxiety: Interplay between Ventral Striatum and Amygdala Reactivity in Sexual Behaviors

Comorbidity of mood/anxiety disorders and addictive behaviors is widely reported in the clinical literature. Many psychological models of addictive and risk behaviors assume an appetitive component (related to impulsivity) and/or a mood regulation component (related to anxiety; [Verheul et al., 1999

Automated detection of cross-frequency coupling in the electrocorticogram for clinical inspection

We developed a toolbox for detecting high-frequency oscillations and evaluating cross-frequency phase-amplitude coupling in electrocorticographic (ECoG) data with optimal parameters. Here we demonstrate use of the toolbox using simulated and realistic ECoG data. The results confirmed its potential usefulness for clinical research or practice. The tools have been released as a Phase-Amplitude Coupling Toolbox (PACT) plug-in for EEGLAB, an open software environment for electrophysiological data analysis (sccn.ucsd.edu/eeglab).