Research projects

月経随伴症とは月経のおよそ2週間前から始まる黄体期に繰り返し出現する倦怠感や痛み、 制御が困難な抑うつや怒りといった心身の不快な症状で心身症の一つとされる。本研究では、心身症の心理的要因の一つであるアレキシサイミア傾向に注目し、その構成で重要な（1）感情の言語化と（2）内受容感覚に着目した介入研究を実施する。（1）にはジャーナリングを、（2）には申請者が開発したスマートフォンアプリを利用する。2か月間の介入前後に月経に伴う気分変動の程度、月経随伴症、心身症状、アレキシサイミア、内受容感覚などを調査し、介入が月経に伴う気分変動の大きさや感情制御の困難さの軽減に効果をもたらすかを検討する。

In this study, we analyzed how autonomic function is altered by insular gyrus removal. Furthermore, by directly stimulating the insular cortex during awake surgery, measuring ECG, heart rate and blood pressure changes, and performing a heartbeat detection task, the aim of this study was to elucidate the neural basis of autonomic functional activity in the insular cortex and establish a next-generation awake brain surgery method to identify autonomic function, preserve function and restore function over time. The performance of direct stimulation and heartbeat detection tasks, as well as their relationship to the surgical site, was investigated in a statistical analysis. Analysis is currently underway in 13 patients who were able to be enrolled, and it has been found that cardiac output tends to decrease as a result of the decrease in systolic blood pressure and increase in peripheral vascular resistance caused by insular stimulation.

本研究では不安傾向やアレキシサイミア(失感情語症)傾向に着目し、感情の認識に内受容感覚(身体内部状態の知覚)の諸側面が及ぼす影響を検討し、因果関係の解明と効果的な介入方法の確立を目指す。感情認識と内受容感覚の関連性は、広く研究者の興味をひいてきた一方、内受容感覚の測定方法の信頼性・妥当性の問題や、複数の測定方法のそれぞれが何を測定対象にしているのか、という議論がないがしろにされた状況にある。不安やアレキシサイミアなどの感情認識傾向との関係性を把握した後に、それぞれの傾向と特に強く関連した内受容感覚の側面を変化させるトレーニングを実施し、その変化が感情認識に及ぼす影響を明らかにする。

この研究において、自律神経機能の同定と機能温存、経時的な機能回復を目的とした次世代型覚醒下手術法の確立を目標とする。また、自律神経系ネットワークの早期回復を目指し、脳腫瘍患者の術後の生命予後の改善のみならず、機能予後改善を図ることを主眼に置いた治療を行う。 眼窩前頭皮質が自律神経と密接に関わることをヒトで検討できる脳神経外科学と、ヒトの感情や自律神経機能を多角的に捉えることができる認知神経科学が、分野融合型の共同研究を行うことは大変意義深いと考える。

我が国では気分障害の患者数が非常に多く，その原因となるメカニズム解明が求められている．実際，さまざまな療法では症状の改善が見られない「ノンリスポンダー」も一定数含まれる．その背景には，自律神経の応答性に個人差がある点，および自らの心臓の動きなどの自律神経活動の変化をどれだけ正確に感じ取ることができるかを示す指標である「内受容感覚」にも個人差がある点が関与している．また生活環境内には，気圧の変化など，自律神経活動を大きく作用する要因がある．そこで本研究では，気圧変化が気分変化とどのような関係にあるかについて，「心ー脳ー身体ー環境」の4者関係の複雑なメカニズム解明を通して明らかにする予定である． 本研究は，精神疾患における気分のゆらぎと身体化の原因について，生活環境要因と心理的要因の効果を統合的に分析することを目的としている．気分の揺らぎはさまざまな原因によって起こる上に，身体化の背景には非常に複雑な要因が関わるため，身体生理機能・中枢神経機能に加え，主観的指標・客観的指標の両者を用いた心理的機能に着目する必要がある．今年度は，気圧の変化およびそれに対する内受容感覚に着目した実験を実施した．具体的には，身体化のなかでも慢性疼痛に深く関与されると考えられる気圧変化の影響について，健常者および身体症状症の症例を対象とした研究を実施した．特に，さまざまな部位に痛みが生じている患者に対して，複数の質問紙による主観報告を確認し，意思決定や感情処理のバイアスかあるか，痛み閾値に特殊性が見出されるか，痛みの感じ方に違いはあるか，などの側面について徹底的な解析を行い，さらに気圧変化時の自律神経動態について詳しく調べた．また自律神経に変化が生じていない状態および生じている状態における内受容感覚を詳細に調べ，主観・客観の両側面から多角的な実験データが取得できた．正確な感知が困難である気圧の変化に対する予測的反応性に着目し，自律神経の反応性をパターン別に分析し，それらの違いがどのような要因によって説明できるかを統合的に解析した．今後も，この実験と解析を継続し，総合的な観点から気分のゆらぎや痛みが生起されるメカニズムについて調べる． 身体症状症研究については，当初，倫理審査審査に時間を要していたが，今年度は順調にリクルートが進み，順調なデータの取得ができている．臨床研究はさまざまな要因によって実験が計画通りに進まないことが多いが，本研究はその点では非常に順調に実験が進められており，データ解析も計画通りに進行している．このペースで次年度の研究も進める予定である．今後は対照となる健常者の実験も同時並行で進めることで，研究の遅れが出ないように工夫する． 上述のとおり，本研究の遂行は順調であり，今後は患者群に加え，健常群対象の実験も同時並行で進める予定である．データが安定している部分については，積極的に学会での発表などを行い，専門家の意見を広く取り入れ，データの解釈に活かしていく予定である．

Somatic symptoms disorder, in which patients complain of pain and other physical symptoms even though there are no obvious symptoms of physical disease, actually occurs in a considerable number of cases, and certain types of psychotherapy are found to be effective. However, the mechanisms underlying their symptoms are not fully understood. In the present study, we focused on three factors highly involved in the occurrence of symptoms: predictive autonomic nervous functions at the body level, interoceptive accuracy, and distortion of thought, and examined them in detail. The results showed that similar changes in autonomic nervous activities were observed not only in the situation of actual atmospheric pressure fluctuations, but also in the situation of merely predicting them, and that the degrees of those changes were partially associated with interoception, somatic symptom characteristics and the degree of distortion of thought.

○We assessed emotion processing in a series of patients who had undergone brain tumor resection in the insular lobe. We found that direct electrical stimulation over the anterior insular cortex during awake brain mapping enhanced anger recognition in these patients. ○The sensitivity of anger recognition significantly deteriorated, while that of sadness improved, when emotional sensitivity was compared before and after surgery. ○We showed that anger recognition is mainly associated with the left insula in a lesion symptom mapping study.

Emotions arise from an integrated understanding of interoception and environmental information. However, this process in the brain has not been fully elucidated. In this study, we focused on fluctuations in autonomic nervous system activity during the female menstrual cycle as an example of how changes in internal body states affect emotions in daily life. One participant was asked to participate in the experiment during the follicular and luteal phases, and data were collected for 34 participants. In each experiment, we assessed interoception, autonomic responses, and emotion recognition tendencies. In addition, fMRI imaging was performed at rest and during task performance. Participants who understood the connection between the body and emotions were shown to be potentially more sensitive to changes in their physical physiological state due to fluctuations in their menstrual cycle.

Interoception, the sense of the internal state of the body, plays an important role in anxiety disorders and other psychiatric disorders, as well as in neurological disorders that cause pain. This effect is likely to occur in situations where anticipatory processing is possible. However, the mechanisms behind these phenomena remain unresolved. We first conducted a study to develop an accurate autonomic index and showed that facial skin blood flow could be an appropriate marker to reflect the fine state of mind. The results of this study may be applied to the treatment of blushing disorder or other anxiety-related disorders. The results of other experiment for the patients with chronic cephalalgia showed that the interoceptive accuracy tended to be lower in the patients, suggesting that it relates to the intensity of pain felt, not the frequency of pain.

Recent studies have investigated the neural mechanisms of emotion and social functions. However, causal factors of anxiety and depression symptoms remain unclear. In this series of studies, we have focused on the mind-brain-body interactions from integrative multiple perspectives and carried out three experimental investigations including an EEG study, an fMRI study, and an autonomic clinical neurological study. Results indicated that specific patterns of automatic thinking including past- of future-oriented thinking were found in depression and anxiety, which relates interoceptive accuracy and autonomic nervous functions. For the neural mechanisms of these specificities, we found the early component of EEG and the activity in the frontopolar area could be the keys to understand anxiety and depression symptoms. Overall findings suggest that we need to address the mind-brain-body interactions for uncovering the behavioral and neural mechanism of psychiatric symptoms.

The research aimed to understand the relationship between interoceptive accuracy, cognitive functions, emotion recognition and neural mechanisms underlying these processing. We focused on age related changes in cognitive functions and emotion for this purpose. Participants from 50s to 70s were involved the research and completed some tasks regarding interoceptive accuracy, emotion recognition, attention and memory. Also, we took their functional and anatomical MRI and examined the association between behavioral performance and its neural mechanism. Though we found the association between interoception and emotion similar to younger population, clear associations between interoception and some cognitive functions, such as working memory or attention, were not observed.