Functional abnormalities in the medial prefrontal cortex (mPFC) provide a biological basis to explain social cognition deficits in patients with schizophrenia, according to a new study published in Schizophrenia Research.
A team of French researchers headed by Annick Razafimandimby, PhD, of the Université de Caen, compared the performance of 21 patients with schizophrenia with that of 25 healthy controls in cognitive tasks while undergoing an event-related functional magnetic resonance imaging (fMRI).
The first task was to classify sentences into three different categories, based on their emotional content (eg, anger, happiness, or sadness). The other task involved classifying sentences according to the grammatical persona of the sentence (ie, first person, second person, or third person), following a slow event-related design, with the different sentences occurring randomly, but in the same order for all subjects.
Shortly after the scanning session, participants were asked to recognize 12 sentences that they had heard during the scanning, from among a total of 24 written sentences for each task. The researchers compared the accuracy (mean number of correct responses) between patients diagnosed with schizophrenia and controls. They evaluated differences in response time of correct responses and number of recognized sentences, and compared the strategies used by the subjects with schizophrenia vs. those used by the control participants.
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The researchers found that patients with schizophrenia showed longer response times, as compared with those of controls (P=0.0097,) and that they recognized significantly fewer sentences than controls (P=0.0095) during the EMO task.
Imaging showed that participants with schizophrenia demonstrated reduction of activation in the bilateral auditory areas, irrespective of the presence of emotions. However, these individuals failed to activate the mPFC during the emotional attribution task—healthy participants, on the other hand, showed a significant activation of this brain region.
According to the researchers, this finding is consistent with previous neuroimaging studies that reported reduced activation in the mPFC in patients with schizophrenia when viewing emotional faces and negative emotional stimuli. Lower mPFC activation was also associated with a longer response time in those with schizophrenia.
The researchers concluded that the functional abnormality in the mPFC during the emotion attribution task “might put the deficit of schizophrenia patients in social cognition into perspective.” These deficits “might play a major role in the cognitive misrepresentation of one’s own and others’ intentions in social interactions, and in the breakdown of communication in patients with schizophrenia.”
Razafimandimby A, Herve PY, Marzloff V, et al. Functional deficit of the medial prefrontal cortex during emotional sentence attribution in schizophrenia. Schizophr Res. 2016. doi: 10.1016/j.schres.2016.09.004. [Epub ahead of print]