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京都大学 / 新制・課程博士 / 博士(人間健康科学) / 甲第24543号 / 人健博第114号 / 新制||人健||8(附属図書館) / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 黒木 裕士, 教授 稲富 宏之, 教授 村井 俊哉 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM

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The present study investigated the effects of meditative practices on the regulation of autonomic function. 74 subjects (38 women; 36 men) comprised from a range of experienced and non-experienced meditators, engaged in a series of psychophysiological tasks designed to generate specific autonomic states. Regression analyses revealed that experienced meditators, as predicted, displayed greater suppression of myocardial reactivity during a highly reflexive and stressful task. Meditative practice also predicted a rise in electrodermal activity during a relaxation task, contrary to expectations. These results support the concept that meditative practices may alter aspects of autonomic function. Further, these results inform an emerging mind-body paradigm and illustrate the potential consequences of meditative practices in specific disease states and prevention. / Ph. D.

Ego-resiliency (ER) is a trait that describes the ability to cope with stress, while effortful control (EC) is an individual difference related to the ability to optimally inhibit negative emotion through attentional mechanisms. ER has been linked to flexible cardiovascular responding without accounting for autonomic nervous system origins of physiological responses. Similarly, EC tends to be associated with increased cardiac vagal control. However, differences in the autonomic characteristics of these constructs remain unclear. In the current study, it was hypothesized that compared to low-scorers, individuals who score high on ER and EC will each have greater vagal control and less sympathetic control over interbeat intervals (IBI) changes during laboratory stressors. Subjects engaged in a mental arithmetic, speech preparation, and verbal fluency task to elicit cardiovascular activation along a continuum of threat. Electrocardiography and impedance cardiography were collected before, during, and after these tasks to assess changes in autonomic functioning. Results from multiple regression analyses indicated that high levels of EC predicted increased vagal control over IBI recovery and less sympathetic reactivity of IBI reactivity. Contrary to predictions, ER showed an opposite pattern of autonomic regulation across stressors. / Master of Science

The dynamic behaviors of a complex organism are explained via voluntary and involuntary action. One underpinning of this system is organized and facilitated by the autonomic nervous system, integrating information from conscious and non-conscious centers in a seemingly hierarchical fashion. As a result, voluntary actions have the ability to inhibit reflexive actions via an inhibitory circuit. 111 subjects performed four diverse autonomic tasks consisting of voluntary and involuntary combinations. Analysis supports the proposed hierarchical model. Each task evoked specific autonomic states. Voluntary tasks influenced autonomic actions more than involuntary tasks. And working memory capacity mediated voluntary control. / Master of Science

Heart rate variability (HRV) has been used to evaluate cardiac autonomic function by measuring variations in electrocardiographic R-R intervals between cardiac cycles. HRV was first used to associate decreases in autonomic nervous system (ANS) control with an increased risk of mortality in coronary heart disease and in the diagnosis of diabetes (1). Current clinical research interest has extended to investigate uses of HRV to evaluate changes in the cardiovascular system due to disease, aging, physical activity, and cardiac rehabilitation treatment (2, 5). HRV scores are derivatives of R-R intervals and these may be represented as a function of either time or frequency domain parameters. Time domain analysis is the simplest and includes: the standard deviation of R-R intervals and the number of adjacent RR intervals that differ by >50ms (dRR50). Frequency domain measures involve more elaborate calculation and have been applied in studies to evaluate sympathetic and parasympathetic autonomic balance. The latter include: Low Frequency Power (LF), High Frequency Power (HF), and LF/HF ratio. HRV has been measured in a variety of ways, the most common being a continuous 24-hour collection of R-R data. In recent years, several investigators have sought to assess HRV by utilizing brief collection periods. Controversy exists about the potential of these short-term sampling intervals to yield reproducible and meaningful measurements of HRV. Many confounders such as respiration, stress, and body positioning can influence HRV, which is why a longer collection period has been accepted as the standard for providing a stable index of ANS function. However, short sampling periods would be useful to evaluate HRV when faced with time constraints. The purpose of the current study was to evaluate the reproducibility of HRV using 8-hour daytime measures with the Polar R-R RecorderTM (Polar Electro Oy, Kempele, Finland) and with short sampling duration of 512 cardiac cycles, using the Schiller AT-10TM device (Schiller AG, Baar, Switzerland). Methods: 10 apparently healthy adult volunteers participated in the study, which was conducted at the Sleep Disorders Clinic in Christiansburg, VA. Each subject performed two HRV trials with the Cardiovit AT-10TM device using recordings of 512 cardiac cycles. Within one or two days following the Schiller, the same subjects wore a Polar R-R RecorderTM device to obtain an 8-hour recording of HRV during waking hours; 24-hour urine samples were collected on the same day. Urine was analyzed for catecholamine levels, including norepinephrine and epinephrine in order to evaluate sympathetic nervous system globally. Each subject recorded their personal impressions of unavoidable physical activity and daytime stress demands on the day of the 8-hour recording and urine collection. This entire protocol was repeated one week later. On one of the days of the short sampling recording, VO2pk also was evaluated for each subject using a ramp protocol on the cycle ergometer and a metabolic cart. Results: The correlation analysis for the HRV response variables using the Schiller method indicated a high-to-very high correlation between trials within a day for the time domain measures (r = 0.75-0.99). The frequency domain measures, however, were low-to-moderately correlated (r = 0.24-0.66) between trials within a day for the Schiller method. Correlations between days for HRV response variables using the Schiller method were similarly low for both time (r < 0.5) and (r < 0.4) frequency domain measures. Correlation coefficients between days for the HRV response variables using the Polar method were moderate (r = 0.59-0.67) for the time domain and only low-moderate for the frequency domain measures (r = 0.37-0.69). However, an important finding was that Polar R-R data for two of the subjects contained excessive signal artifact, which affected the fidelity of the HRV scores. When these two cases were excluded from the group analyses, the resulting correlations were high-very high for all time and frequency domain measures (r = 0.70-0.93). The means for each response HRV time and frequency domain variable between the Polar method and Schiller method were significantly different (P < 0.05). Additional correlational analyses did not reveal any systematic associations between HRV measures and simple markers of sympathetic activity (urinary NE or E) and aerobic fitness (VO2pk) in this small sample of subjects. Conclusions: Due to this important change in reproducibility with the Polar method, the consequence of artifact-free recordings is unmistakable. Within the limitations of this small study sample it is concluded that, while HRV in apparently healthy adults may not be measured reliably with brief data collection periods, longer daytime sampling periods of 8 hours (e.g. Polar device) yields acceptable reliability for both time and frequency domain parameters of HRV. / Master of Science

Purpose To characterize differences in autonomic cardiovascular regulation after spinal cord injury compared to people without spinal cord injury through objective laboratory and subjective survey data, and to determine the component contribution of group III and group IV muscle afferents to overall autonomic integrity after spinal cord injury. Methods Individuals with spinal cord injury (n = 36), aged 18 years or older, and similarly age and gender matched individuals without spinal cord injury (n = 44) completed the Autonomic Dysfunction After Spinal Cord Injury (ADFSCI) survey. To test physiologic responses to a well-characterized, autonomic test as well as pilot another objective test, seven individuals with spinal cord injury and 10 individuals from the uninjured control group then completed further laboratory testing, including Valsalva maneuvers and ischemic hand grip. Results Individuals with spinal cord injury had neurological levels of injury C3-T12 and injuries graded A-D on the American Spinal Injury Association Impairment Scale (AIS). Individuals with spinal cord injury scored significantly higher by endorsing more daily symptoms of autonomic dysfunction on the ADFSCI survey compared to their uninjured peers (W = 272, p < 0.0001). However, in the group with spinal cord injury, higher ADFSCI scores were only weakly positively correlated with higher neurological level injury (R = 0.37, n = 36, p = 0.03) and more complete (AIS A or B) injury (R = 0.46, p = 0.01). Furthermore, the subgroup with spinal cord injury (n = 7) who completed laboratory testing displayed significantly altered blood pressure response during late phase II of the Valsalva maneuver compared to controls (p = 0.02). The same group of individuals with spinal cord injury also demonstrated a significantly lower maximal diastolic blood pressure in response to ischemic hand grip when compared to the control group (p = 0.04). Conclusion Self-reported daily symptoms of autonomic dysfunction are markedly higher after spinal cord injury. However, the relationship between these symptoms and neurological level of injury and AIS are only weakly correlated. This nonlinear relationship between ADFSCI scores and clinical injury characteristics emphasizes the need for further characterization of autonomic integrity. Physiologic laboratory tests more completely capture these alterations after spinal cord injury and point to developing bedside exams. / 2026-10-30T00:00:00Z

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 5 uppsatser.

The autonomic nervous system (ANS) controls most involuntary functions of the body. Dysfunctions of the ANS can be life-threatening. However, several critical questions related to cardiovascular and breathing regulations remain unclear. One of the open questions is how the system lose control of the vascular tones under certain circumstances. Using the septic shock model induced by lipopolysaccharide (LPS) in isolated and perfused mesenteric arterial rings, we found the vascular hyporeactivity is attributed to the decreased vasoconstriction to α-adrenoceptor agonists. The endotoxin-induced vasodilation can be intervened with endothelin-1 (ET-1), serotonin (5-HT) or vasopressin, which have never been used in clinical treatment. It is unclear how the excitability of endothelium affects vascular tones. Using optogenetics and transgenic mice with channelrhodopsin expression in endothelial cells (ECs), we found selective activation of the ECs induces a fast, robust, reproducible and long-lasting vasoconstriction in isolated and perfused hearts and kidneys. Breathing control by the ANS within the brain becomes abnormal in certain genetic diseases, such as Rett syndrome with defected norepinephrine (NE) system in locus coeruleus (LC). The LC neurons are hyperexcitable while NE release is deficient. Using optogenetics and double transgenic mice with Mecp2 null and channelrhodopsin expression in LC neurons, we found the NE-ergic modulation of hypoglossal neurons was impaired in transgenic mice, which cannot be improved with optostimulation, suggesting that LC neuronal hyperexcitability may not benefit the NE modulation in Rett syndrome. Collectively, our results provide insight into the autonomic dysfunctions using experimental interventions that have barely been used before.