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Abnormal neural responses may explain social behavior in schizotypal personality disorder

Individuals with schizotypal personality disorder exhibited increased activation in brain regions related to reward and decision making when viewing biological motion stimuli, which may be related to their social behavior.

“Exploration of the ability to process socially relevant events portrayed by biological motion and to identify underlying neuronal processes can provide clues for understanding the pathophysiology of psychosis,” Ji-Won Hur, PhD, of Seoul National University, Republic of Korea, and colleagues wrote. “Individuals with schizotypal personality disorder (SPD) have pervasive interpersonal deficits and odd behaviors. An understanding of the neural mechanisms involved in the perception of biological motion and the relation of activity to clinical symptoms in those mechanisms is needed.”

To assess specificity of brain regions responsive to biological motion perception in individuals with SPD, researchers conducted functional MRI among 21 patients with SPD and 38 controls matched for age, sex and IQ. Study participants had an approximate mean age of 22 years.

Brain imaging indicated the presence of neuronal activation specific to biological motion within the posterior superior temporal sulcus. However, individuals with SPD exhibited neural responsiveness in brain regions forming the reward network, specifically the dorsal striatum and bilateral superior medial frontal cortex (P < .002 for all clusters).

Individuals with SPD exhibited reduced activation in the anterior and middle cingulate cortices and the lingual and superior occipital gyri, which respond to biological motion perception and executive control of perception (P < .001 for all clusters).

Further, researchers observed significant correlations between the hyperdopaminergic clinical symptoms and increased neuronal activation in the caudate nucleus and frontal cortex in individuals with SPD (P < .02).

“We have obtained suggestive evidence that the brain in patients diagnosed as having SPD exhibits unusual patterns of neural activity in response to viewing biological motion sequences,” the researchers wrote. “These findings may help to characterize the interaction between disturbed reward circuitry and the bizarre ways of perceiving and experiencing social stimuli observed in individuals with SPD, whose condition tends to isolate them from everyday social interaction.” – by Amanda Oldt

Disclosure: The researchers report no relevant financial disclosures.