Postural tachycardia syndrome (PoTS) is assumed as a heterogeneous clinical syndrome, but it is absurd to discuss its nature under the single term of PoTS unless all variants of PoTS share the common pathophysiology. Review of the past studies on PoTS indicates that the nature of PoTS had already been theoretically elucidated. The present concept of PoTS corresponds to Da Costa syndrome (1871) in the English-speaking world, vagal neurosis (1892) or vegetative dystonia (1934) in the German-speaking world, and arterial orthostatic anemia (1925) in Sweden. In the English- and the German-speaking worlds, PoTS was considered as a condition coexisting with both the autonomic and the affective disturbances (psychosomatic disease). The interpretation of psychosomatic disease was different between the English- and the German-speaking world, however; while it was simply considered that the autonomic nervous activity was influenced by the affection in the former, it was speculated that interoception (centripetal impulse from the inner organs) produced both the autonomic nervous activity and the affection within the central autonomic network. In Sweden, PoTS had been recognized as a venous pooling syndrome due to deficient autonomic venous regulation, shelving the problem of the affective disturbance; the present concept of PoTS is rediscovery of the Swedish doctrine. Today, evidence has been accumulating that the affective disturbance in PoTS is caused by disturbance (increase?) in the interoception. When the interoception theory is adopted, the deficient autonomic venous regulation in PoTS can be necessariry explained by the excessive unloading of the cardio-pulmonary baroreflex while standing.

The Japanese medical term Hiesho means cold hypersensitivity in the extremities and easily feeling cold in people without any pathological disorders. Hiesho is reported to occur in about 60% of healthy women and 20% of healthy men. People with Hiesho often have lower body weight and body mass index and are less active than people without Hiesho, and they also have associated symptoms, such as shoulder stiffness, easy fatigability, headache, constipation, depressive mood, lumbago, and dizziness. Measurements of heart rate, R-R interval variability (on electrocardiogram), and skin blood flow (by laser Doppler) showed that the pathophysiological mechanism of Hiesho is sympathetic hyperactivity, which contributes to subjective coldness and decreased skin temperature. A reperfusion study after transient arm ischemia revealed greater vascular endothelial dysfunction in younger participants than in older ones. In sympathetic nerve recordings, skin sympathetic nerve activity in response to body cooling increased significantly larger in younger people than in older ones. These findings indicate that excessive elevation of skin sympathetic nerve activity in younger people is related to decreased skin blood flow in the extremities.

Progressive supranuclear palsy (PSP) is one of the common four-repeat tauopathies. Clinical symptoms of autonomic dysfunction, such as orthostatic hypotension, urogenital disorder, pupillomotor function, and central hypoventilation, frequently recommend differential diagnosis from α-synucleinopathies, Parkinson’s disease, dementia with Lewy bodies, and multiple system atrophy (MSA). In this mini review, we focus on neuropathology of autonomic nervous system in PSP. Pathologically, 4 repeat tau positive neuroglial inclusions, neurofibrillary tangles, pretangles, threads, and coiled bodies are consistently observed in autonomic nervous system in PSP, including intermediolateral nucleus, Onuf ’s nucleus, Edinger-Westphal nucleus, and ventrolateral nucleus of the medulla. Neuronal loss of the intermediolateral nucleus and Onuf ’s nucleus is less prominent in PSP compared to MSA. Furthermore, 4 repeat tau pathology in PSP is also remarkable in higher control circuitry relevant to autonomic function, involving medial fontal cortex, ventral tegmental area of midbrain, and pontine tegmental area. Therefore, autonomic dysfunction of PSP may correlate with combination of the tauopathy in these characteristic autonomic nuclei and higher neuronal circuitry relevant to autonomic system.

Emotions are accompanied by physical reactions, such as facial expressions and heart rate changes. This paper focuses on facial skin blood flow (SkBF) as an index of the autonomic nervous system. Facial SkBF is a unique indicator compared to heart rate or sweating because it is related to facial temperature and facial color changes. The SkBF does not react uniformly in all areas of the face and has different reactivity in each part of the face, such as the forehead, cheek, or nose. In several previous studies, the time window for the analyses was about 30 seconds or more, however, focusing on short-term rapid responses, e.g. 5 seconds, is critical for clarifying the mechanisms of mental disorders related to facial SkBF and clinical intervention.

With the development of new drugs, such as molecular-targeted agents, and advances in medical technology, the number of cancer survivors is increasing every year. However, some anticancer drugs, particularly immune checkpoint inhibitors, have been found to cause potentially lethal cardiovascular dysfunction, and there is concern that this may affect the prognosis and quality of life of cancer patients. In addition, it has become clear that cancer itself and cancer cachexia, which occurs as cancer progresses, also cause cardiac dysfunction. Therefore, the prevention and treatment of cancer cachexia and cancer treatment-induced cardiac dysfunction are urgent issues. Exercise therapy has been reported to improve the prognosis of patients with chronic heart failure, as well as prevent the recurrence of cancer, and assists the completion of anticancer therapy in cancer patients. This review outlines the therapeutic effects of exercise therapy as a new treatment modality for cardiac dysfunction associated with cancer treatment, especially during cancer cachexia.

Interoception is the perception of the internal bodily state, including the autonomic nervous system. Recently, heartbeat evoked potentials (HEP) have been proposed as a measure of interoception. HEP is considered a brain potential with high temporal resolution reflecting afferent signals from the cardiovascular system without the need for subjective reporting. HEP relates to various cognitive responses such as attention, emotion, self-awareness, and symptoms of psychiatric disorders. In this review, we overview the studies of HEP, which is expected to be a useful index of mind-body interactions, and discuss the relationship between interoception and cognitive functions.