Biopsychosocial intersections of social/affective touch and psychiatry: Implications of ‘touch hunger’ during COVID-19

Background: Humans are neurobiologically wired for touch receptivity. Social touch is a common and mutual way of expressing affection, care, and intimacy. From an evolutionary perspective, affiliative and affectionate touch are considered necessary for social and cognitive development throughout life-stages and across species. The emergence of the COVID-19 pandemic as a public health threat has mandated social distancing as a measure to contain the global outbreak. Travel restrictions, lockdown, and quarantine have led to separation and segregation, giving rise to social touch deprivation that might have adverse biopsychosocial consequences. Methods: Affective touch has rarely been discussed within the purview of social psychiatry. We attempted to review the neurobiological, social, and behavioural correlates of social and sexual touch, as well as the neurophysiological models involved. Results: The unmyelinated peripheral C-fibre afferents projecting to insular cortex and somatosensory areas form the prime pathway for affective touch. ‘Top-down’ modulation via the periaqueductal grey area, rostroventral medulla and sub-cortical structures, and ‘Bottom-up’ approach via the dorsal horn of the spine form the two theoretical models of ‘social touch’ system. The mu - opioid receptor (MOR) implicated in the Brain Opioid Theory of Social Attachment (BOTSA) and social neuropeptides like oxytocin and vasopressin are the primary neurochemical substrates involved. Sexual intimacy involves other neurotransmitters, with increased oxytocin activity in the limbic structures, Nucleus Accumbens, Anterior Cingulate, and Prefrontal Cortex. The discrimination and amalgamation of touch senses, their affiliative value and emotional valence in humans are based on a complex interplay between psychobiological, environmental, and personal factors. Conclusion: The neurobehavioral and emotional effects of ‘touch hunger’ and strategies to mitigate it during COVID-19 are discussed in the context of psychoneuroimmunity and stress.

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The human cortical autonomic network and volitional exercise in health and disease

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2018-0305 ◽

2018 ◽

Vol 43 (11) ◽

pp. 1122-1130 ◽

Cited By ~ 7

Author(s):

Baraa K. Al-Khazraji ◽

J. Kevin Shoemaker

Keyword(s):

Current Knowledge ◽

Insular Cortex ◽

Cardiovascular Control ◽

Anterior Cingulate ◽

Disease States ◽

Autonomic Activation ◽

Imaging Research ◽

Health And Disease ◽

Cortical Regions

The autonomic nervous system elicits continuous beat-by-beat homeostatic adjustments to cardiovascular control. These modifications are mediated by sensory inputs (e.g., baroreceptors, metaboreceptors, pulmonary, thermoreceptors, and chemoreceptors afferents), integration at the brainstem control centres (i.e., medulla), and efferent autonomic neural outputs (e.g., spinal, preganglionic, and postganglionic pathways). However, extensive electrical stimulation and functional imaging research show that the brain’s higher cortical regions (e.g., insular cortex, medial prefrontal cortex, anterior cingulate cortex) partake in homeostatic regulation of the cardiovascular system at rest and during exercise. We now appreciate that these cortical areas form a network, namely the “cortical autonomic network” (CAN), which operate as part of a larger central autonomic network comprising 2-way communication of cortical and subcortical areas to exert autonomic influence. Interestingly, differential patterns of CAN activity and ensuing cardiovascular control are present in disease states, thereby highlighting the importance of considering the role of CAN as an integral aspect of cardiovascular regulation in health and disease. This review discusses current knowledge on human cortical autonomic activation during volitional exercise, and the role of exercise training on this activation in both health and disease.

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Autonomic Nervous System

10.1093/med/9780197512166.003.0019 ◽

2021 ◽

pp. 158-168

Author(s):

Jeremy K. Cutsforth-Gregory

Keyword(s):

Nervous System ◽

Autonomic Nervous System ◽

Insular Cortex ◽

Anterior Cingulate ◽

Nucleus Ambiguus ◽

Ventrolateral Medulla ◽

Autonomic Nervous ◽

Parasympathetic Nerves ◽

System P ◽

Functional Components

The autonomic nervous system is involved in many important unconscious body functions. It is critical for maintaining the internal environment in response to changes in the external environment. The autonomic nervous system consists of peripheral components (sympathetic and parasympathetic nerves and ganglia) and central components (ventrolateral medulla, nucleus ambiguus, nucleus of the solitary tract, periaqueductal gray, anterior cingulate gyrus, insular cortex, amygdala, and hypothalamus). This chapter briefly reviews the anatomy and functional components of the autonomic nervous system and several anatomical clinical correlations.

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Manganese-enhanced MRI depicts a reduction in brain responses to nociception upon mTOR inhibition in chronic pain rats

Molecular Brain ◽

10.1186/s13041-020-00687-1 ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Myeounghoon Cha ◽

Songyeon Choi ◽

Kyeongmin Kim ◽

Bae Hwan Lee

Keyword(s):

Chronic Pain ◽

Nerve Injury ◽

Pain Perception ◽

Imaging Techniques ◽

Insular Cortex ◽

Pain Modulation ◽

Anterior Cingulate ◽

Related Area ◽

Mtor Inhibition ◽

The Brain

AbstractNeuropathic pain induced by a nerve injury can lead to chronic pain. Recent studies have reported hyperactive neural activities in the nociceptive-related area of the brain as a result of chronic pain. Although cerebral activities associated with hyperalgesia and allodynia in chronic pain models are difficult to represent with functional imaging techniques, advances in manganese (Mn)-enhanced magnetic resonance imaging (MEMRI) could facilitate the visualization of the activation of pain-specific neural responses in the cerebral cortex. In order to investigate the alleviation of pain nociception by mammalian target of rapamycin (mTOR) modulation, we observed cerebrocortical excitability changes and compared regional Mn2+ enhancement after mTOR inhibition. At day 7 after nerve injury, drugs were applied into the intracortical area, and drug (Vehicle, Torin1, and XL388) effects were compared within groups using MEMRI. Therein, signal intensities of the insular cortex (IC), primary somatosensory cortex of the hind limb region, motor cortex 1/2, and anterior cingulate cortex regions were significantly reduced after application of mTOR inhibitors (Torin1 and XL388). Furthermore, rostral-caudal analysis of the IC indicated that the rostral region of the IC was more strongly associated with pain perception than the caudal region. Our data suggest that MEMRI can depict pain-related signal changes in the brain and that mTOR inhibition is closely correlated with pain modulation in chronic pain rats.

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Combined Parietal-Insular-Striatal Cortex Stroke with New-Onset Hallucinations: Supporting the Salience Network Model of Schizophrenia

Psychiatry Journal ◽

10.1155/2020/4262050 ◽

2020 ◽

Vol 2020 ◽

pp. 1-6

Author(s):

Saheba Nanda ◽

Krishna Priya ◽

Tasmia Khan ◽

Puja Patel ◽

Heela Azizi ◽

...

Keyword(s):

Functional Integration ◽

Insular Cortex ◽

Brain Regions ◽

Anterior Cingulate ◽

Psychotic Symptoms ◽

Salience Network ◽

Schizophrenic Patients ◽

Cortical Circuit ◽

The Brain ◽

New Onset

Brain imaging studies have identified multiple neuronal networks and circuits in the brain with altered functioning in patients with schizophrenia. These include the hippocampo-cerebello-cortical circuit, the prefrontal-thalamic-cerebellar circuit, functional integration in the bilateral caudate nucleus, and the salience network consisting of the insular cortex, parietal anterior cingulate cortex, and striatum, as well as limbic structures. Attributing psychotic symptoms to any of these networks in schizophrenia is confounded by the disruption of these networks in schizophrenic patients. Such attribution can be done with isolated dysfunction in any of these networks with concurrent psychotic symptoms. We present the case of a patient who presents with new-onset hallucinations and a stroke in brain regions similar to the salience network (insular cortex, parietal cortex, and striatum). The implication of these findings in isolating psychotic symptoms of the salience network is discussed.

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Medial Cortical Structures Mediate Implicit Trustworthiness Judgments about Kin Faces, but Not Familiar Faces: A Brief Report

Psych ◽

10.3390/psych1010037 ◽

2019 ◽

Vol 1 (1) ◽

pp. 482-490 ◽

Cited By ~ 1

Author(s):

Steven M. Platek ◽

Judson C. Hendry

Keyword(s):

Right Hemisphere ◽

Kin Recognition ◽

Insular Cortex ◽

Neural Correlates ◽

The Self ◽

Anterior Cingulate ◽

Dorsal Anterior Cingulate Cortex ◽

Facial Stimuli ◽

The Right ◽

Processing Network

Human kin recognition activates substrates of the extended facial processing network, notably the right-hemisphere structures involved in self-face recognition and posterior medial cortical substrates. To understand the mechanisms underlying prosociality toward kin faces in comparison to other familiar faces, we investigated the neural correlates of implicit trustworthiness ratings to faces of actual kin and personal friends, controlling for activation to distracter faces. When controlling for activation associated with unknown faces, trustworthiness ratings of faces of kin, compared to friends, were associated with increased activation in the dorsal anterior cingulate cortex, posterior cingulate, and precuneous. On the other hand, trustworthiness ratings of friend faces, relative to kin faces, were associated with the lateral occipital gyrus and insular cortex. Trustworthiness ratings for unknown faces were only associated with activation in the fusiform gyrus. These findings suggest that we should employ medial cortical substrates known to be part of the self-other network when making implicit social judgements about kin, but not other classes of facial stimuli.

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Distinction of self-produced touch and social touch at cortical and spinal cord levels

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1816278116 ◽

2019 ◽

Vol 116 (6) ◽

pp. 2290-2299 ◽

Cited By ~ 12

Author(s):

Rebecca Boehme ◽

Steven Hauser ◽

Gregory J. Gerling ◽

Markus Heilig ◽

Håkan Olausson

Keyword(s):

Spinal Cord ◽

Social Cognitive ◽

Superior Temporal Gyrus ◽

Anterior Cingulate ◽

Parahippocampal Gyrus ◽

Brain Areas ◽

Differential Encoding ◽

Social Touch ◽

Tactile Stimuli ◽

The Individual

Differentiation between self-produced tactile stimuli and touch by others is necessary for social interactions and for a coherent concept of “self.” The mechanisms underlying this distinction are unknown. Here, we investigated the distinction between self- and other-produced light touch in healthy volunteers using three different approaches: fMRI, behavioral testing, and somatosensory-evoked potentials (SEPs) at spinal and cortical levels. Using fMRI, we found self–other differentiation in somatosensory and sociocognitive areas. Other-touch was related to activation in several areas, including somatosensory cortex, insula, superior temporal gyrus, supramarginal gyrus, striatum, amygdala, cerebellum, and prefrontal cortex. During self-touch, we instead found deactivation in insula, anterior cingulate cortex, superior temporal gyrus, amygdala, parahippocampal gyrus, and prefrontal areas. Deactivation extended into brain areas encoding low-level sensory representations, including thalamus and brainstem. These findings were replicated in a second cohort. During self-touch, the sensorimotor cortex was functionally connected to the insula, and the threshold for detection of an additional tactile stimulus was elevated. Differential encoding of self- vs. other-touch during fMRI correlated with the individual self-concept strength. In SEP, cortical amplitudes were reduced during self-touch, while latencies at cortical and spinal levels were faster for other-touch. We thus demonstrated a robust self–other distinction in brain areas related to somatosensory, social cognitive, and interoceptive processing. Signs of this distinction were evident at the spinal cord. Our results provide a framework for future studies in autism, schizophrenia, and emotionally unstable personality disorder, conditions where symptoms include social touch avoidance and poor self-vs.-other discrimination.

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Insular cortex and neuropsychiatric disorders: A review of recent literature

European Psychiatry ◽

10.1016/j.eurpsy.2007.02.006 ◽

2007 ◽

Vol 22 (6) ◽

pp. 387-394 ◽

Cited By ~ 195

Author(s):

M. Nagai ◽

K. Kishi ◽

S. Kato

Keyword(s):

Sensory Information ◽

Insular Cortex ◽

Superior Temporal Gyrus ◽

Neuropsychiatric Disorders ◽

Anterior Cingulate ◽

Association Cortex ◽

Amygdaloid Body ◽

Computer Search ◽

Neuropsychiatric Diseases ◽

Motor Information

AbstractThe insular cortex is located in the centre of the cerebral hemisphere, having connections with the primary and secondary somatosensory areas, anterior cingulate cortex, amygdaloid body, prefrontal cortex, superior temporal gyrus, temporal pole, orbitofrontal cortex, frontal and parietal opercula, primary and association auditory cortices, visual association cortex, olfactory bulb, hippocampus, entorhinal cortex, and motor cortex. Accordingly, dense connections exist among insular cortex neurons. The insular cortex is involved in the processing of visceral sensory, visceral motor, vestibular, attention, pain, emotion, verbal, motor information, inputs related to music and eating, in addition to gustatory, olfactory, visual, auditory, and tactile data. In this article, the literature on the relationship between the insular cortex and neuropsychiatric disorders was summarized following a computer search of the Pub-Med database. Recent neuroimaging data, including voxel based morphometry, PET and fMRI, revealed that the insular cortex was involved in various neuropsychiatric diseases such as mood disorders, panic disorders, PTSD, obsessive-compulsive disorders, eating disorders, and schizophrenia. Investigations of functions and connections of the insular cortex suggest that sensory information including gustatory, olfactory, visual, auditory, and tactile inputs converge on the insular cortex, and that these multimodal sensory information may be integrated there.

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Differentiation of Visceral and Cutaneous Pain in the Human Brain

Journal of Neurophysiology ◽

10.1152/jn.01048.2002 ◽

2003 ◽

Vol 89 (6) ◽

pp. 3294-3303 ◽

Cited By ~ 156

Author(s):

Irina A. Strigo ◽

Gary H. Duncan ◽

Michel Boivin ◽

M. Catherine Bushnell

Keyword(s):

Primary Motor Cortex ◽

Visceral Pain ◽

Insular Cortex ◽

Anterior Cingulate ◽

Contact Heat ◽

Activation Patterns ◽

Cutaneous Pain ◽

Muscle Tissues ◽

Balloon Distention ◽

Parietal Cortices

The widespread convergence of information from visceral, cutaneous, and muscle tissues onto CNS neurons invites the question of how to identify pain as being from the viscera. Despite referral of visceral pain to cutaneous areas, individuals regularly distinguish cutaneous and visceral pain and commonly have contrasting behavioral reactions to each. Our study addresses this dilemma by directly comparing human neural processing of intensity-equated visceral and cutaneous pain. Seven subjects underwent fMRI scanning during visceral and cutaneous pain produced by balloon distention of the distal esophagus and contact heat on the midline chest. Stimulus intensities producing nonpainful and painful sensations, interleaved with rest periods, were presented in each functional run. Analyses compared painful to nonpainful conditions. A similar neural network, including secondary somatosensory and parietal cortices, thalamus, basal ganglia, and cerebellum, was activated by visceral and cutaneous painful stimuli. However, cutaneous pain evoked higher activation bilaterally in the anterior insular cortex. Further, cutaneous but not esophageal pain activated ventrolateral prefrontal cortex, despite higher affective scores for visceral pain. Visceral but not cutaneous pain activated bilateral inferior primary somatosensory cortex, bilateral primary motor cortex, and a more anterior locus within anterior cingulate cortex. Our results reveal a common cortical network subserving cutaneous and visceral pain that could underlie similarities in the pain experience. However, we also observed differential activation patterns within insular, primary somatosensory, motor, and prefrontal cortices that may account for the ability to distinguish visceral and cutaneous pain as well as the differential emotional, autonomic and motor responses associated with these different sensations.

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