Neuroscientists Find Brain Region Responsible For Our Sense of Personal Space
On August 30, the Science Daily revealed that a finding that sheds new light on the neural mechanisms involved in social behavior. Neuroscientists at the California Institute of Technology (Caltech) have pinpointed the brain structure responsible for our sense of personal space which scientist hope to gain insight from into autism and other disorders pertinent to social distance.
The scientists, led by Ralph Adolphs, Bren Professor of Psychology and Neuroscience and professor of biology and postdoctoral scholar Daniel P. Kennedy, were able to make the link between the amygdale and real-life human social interaction through a unique patient, a 42-year-old woman known as SM, who has extensive damage to the amygdala on both sides of her brain.
SM has difficulty recognizing fear in the faces of others, and in judging the trustworthiness of someone, two consequences of amygdala lesions that Adolphs and colleagues published in prior studies. Additionally, during his years of studying her, Adolphs also noticed that the very outgoing SM is almost too friendly, to the point of “violating” what others might perceive as their own personal space. “She is extremely friendly, and she wants to approach people more than normal. It’s something that immediately becomes apparent as you interact with her,” says Kennedy.
Previous studies of humans never had revealed an association between the amygdala and personal space. From their knowledge of the literature, however, the researchers knew that monkeys with amygdala lesions preferred to stay in closer proximity to other monkeys and humans than did healthy monkeys.
The experiment used what is known as the stop-distance technique. Briefly, the subject (SM or one of 20 other volunteers, representing a cross-section of ages, ethnicities, educations, and genders) stands a predetermined distance from an experimenter, then walks toward the experimenter and stops at the point where they feel most comfortable. The chin-to-chin distance between the subject and the experimenter is determined with a digital laser measurer.
Among the 20 other subjects, the average preferred distance was .64 meters—roughly two feet. SM’s preferred distance was just .34 meters, or about one foot. Unlike other subjects, who reported feelings of discomfort when the experimenter went closer than their preferred distance, there was no point at which SM became uncomfortable; even nose-to-nose, she was at ease.
While this theory has not been recurrently proven, it is the foundation on which scientists can begin a new series of testing in the human brain. To learn more about the latest news on brain research visit the neuroscience department at NorthShore University HealthSystem.
