New research finds that impairment in a brain area make it difficult for people with schizophrenia to understand the nonverbal actions of others.
“Misunderstanding social situations and interactions are core deficits in schizophrenia,” said psychologist Dr. Sohee Park of Vanderbilt University. “Our findings may help explain the origins of some of the delusions involving perception and thoughts experienced by those with schizophrenia.”
Researchers found that a particular brain area, the posterior superior temporal sulcus or STS, appears to be implicated in this deficit.
“Using brain imaging together with perceptual testing, we found that a brain area in a neural network involved in perception of social stimuli responds abnormally in individuals with schizophrenia,” said co-author Randolph Blake, Ph.D.
“We found this brain area fails to distinguish genuine biological motion from highly distorted versions of that motion.”
“We have found… that people with schizophrenia tend to ‘see’ living things in randomness and this subjective experience is correlated with an increased activity in the (posterior) STS,” the authors wrote.
“In the case of biological motion perception, these self-generated, false impressions of meaning can have negative social consequences, in that schizophrenia patients may misconstrue the actions or intentions of other people.”
In their experiments, the researchers compared the performance of people with schizophrenia to that of healthy controls on two visual tasks.
One task involved deciding whether or not an animated series of lights depicted the movements of an actor’s body. The second task entailed judging subtle differences in the actions depicted by two similar animations viewed side by side.
On both tasks, people with schizophrenia performed less well than the healthy controls.
Next, the researchers measured brain activity using functional magnetic resonance imaging (fMRI) while the subjects—healthy controls and schizophrenia patients—performed a version of the side-by-side task.
Once again, the individuals with schizophrenia performed worse on the task. The researchers were then able to correlate those performance deficits with the brain activity in each person.
Researchers do not yet understand this specific brain area in schizophrenia patients fails to differentiate normal human activity from non-human motion. They speculate that this abnormal brain activation contributes to the patients’ difficulties reading social cues in the actions of others.
Their findings are published in the journal PLoS ONE.
Source: Vanderbilt University