A welcoming hug. An unwelcomed hug. A soothing caress. A repulsive caress. How can social touch go from being a pleasurable experience to offensive? New research by Katalin Gothard, MD, PhD, on the brain’s role in determining emotional responses to touch could lead to a better understanding of social and mental disorders.
Touch is our first emotional language, communicating feelings of pleasure and pain and laying the foundation for social bonds. Despite the widely recognized importance of touch throughout life, remarkably little is known about how touch and emotions are linked at a cellular level in the brain.
Dr. Gothard, a neuroscientist and a professor in the Department of Physiology at the University of Arizona College of Medicine – Tucson, has pioneered research examining cellular brain activity and emotional responses elicited by touch. Findings from Dr. Gothard’s research could help to better understand psychiatric illnesses, such as autism, schizophrenia and social phobia. Patients who suffer from these disorders often fail to understand the social and emotional signals communicated through touch.
Her experience with orphanages in Romania in the 1980s and 1990s – where infants and toddlers were deprived of social and affective touch – left Dr. Gothard strongly motivated to understand why the lack of touch in infancy has such profound effects on social and emotional behavior later in life.
“Many of these orphans, even if they were adopted by loving parents, failed to develop an emotional attachment to their parents or to others,” she said. “It is as though the protective embrace of the parent in early life is necessary for the brain to develop the foundations for social bonding.”
The Gothard Lab is among the first to look at the role of the amygdala – one of two almond-shaped clusters of nuclei deep in the brain that processes emotional memory, decision-making and emotional responses – in evaluating the link between emotion and touch. Her recently published research in the March 11 issue of The Journal of Neuroscience, “Multisensory neurons in the primate amygdala,” demonstrated that neurons in the amygdala that respond to touch, respond to sights and sounds too, integrating multiple facets of social interactions.
Dr. Gothard recently received a $2.1 million grant from the National Institutes of Health, National Institute of Mental Health to further her research on the brain’s response to touch, focusing on how the various types of touch can acquire such social and emotional significance in the brain.
As one of our five senses, touch helps us understand the world through signals that originate at complex receptors in the skin and connect to the brain through an intricate pathway running through peripheral nerves, the spinal cord and multiple brain-processing stations.
“We are looking at how the brain transforms the objective qualities of touch, such as location, pressure, etc., into subjective qualities, such as pleasantness,” Dr. Gothard explained.
“Touch can evoke strong positive feelings, especially when delivered by a trusted and loved individual. However, the same touch, delivered to the same area of the skin by a different individual can flip the subjective experience from pleasure to displeasure, even disgust.”
The amygdala most likely plays a key role in determining the emotional response to touch because the amygdala is known to extract the social and emotional significance of all other sensory stimuli (sights, sounds, tastes, smells). It is the part of the brain that decides whether the sensory stimuli we receive are pleasant, unpleasant or neutral.
“Our research will determine whether tactile cells in the amygdala respond to the subjective value of touch,” Dr. Gothard said. “Specifically, we monitor simultaneously neural responses to touch in the amygdala and the somatosensory cortex – the area of the brain that receives all sensory input from the body – and compare neural responses to the same type of social touch, delivered to the same skin area, by two individuals with whom the recipient has a different social experience.”
Dr. Gothard also has joint faculty appointments in the UA Departments of Neurology and Neuroscience and in the Center for Translational Social Neuroscience at Emory University. Her research team includes Jeremiah Morrow, a UA doctoral student, Rose Andersen, who is starting medical school at the UA, and SeungHyun Lee, a graduate student in Electrical and Computer Engineering. She is collaborating with Andrew Fuglevand, PhD, a sensory-motor neurophysiologist in the Department of Physiology.
"It is important to understand the whole language of touch. Identifying the cellular machinery of affective touch in the brain can provide important insights into why touch processing is so profoundly altered in some patients,” Dr. Gothard said.
Research reported in this release was supported by the National Institutes of Health, National Institute of Mental Health, under grant No. 1R56MH115681-01. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.
About the UA College of Medicine – Tucson
The University of Arizona College of Medicine – Tucson is shaping the future of medicine through state-of-the-art medical education programs, groundbreaking research and advancements in patient care in Arizona and beyond. Founded in 1967, the college boasts more than 50 years of innovation, ranking among the top medical schools in the nation for research and primary care. Through the university's partnership with Banner Health, one of the largest nonprofit health-care systems in the country, the college is leading the way in academic medicine. For more information, please visit medicine.arizona.edu.