Individuals with schizophrenia are distracted by emotional information, which is uniquely caused by reduced activity between the amygdala and the medial prefrontal cortex, according to a new study published this February in Schizophrenia Bulletin.
Psychotic disorders, such as schizophrenia, are characterized by deficits in cognitive control, with previous evidence showing impairments in both focusing upon relevant information and ignoring irrelevant information. More specifically, it has been shown that irrelevant emotional information can disrupt attention during tasks in psychotic disorders, when compared with healthy individuals.
Being able to maintain focus in the presence of distracting emotional information involves a network of brain regions acting together. These regions include the amygdala – important in emotional processing – as well as the anterior cingulate cortex and medial prefrontal cortex – which are involved in emotion appraisal and regulation.
The study, led by Prerona Mukherjee of the University of California, Davis, involved 76 participants (26 with schizophrenia; 21 with bipolar disorder with psychosis; and 29 control participants with no history of psychotic disorders). A task was completed in which participants had to identify faces (relevant information) whilst ignoring the emotional expressions of the faces (irrelevant information). Functional magnetic resonance imaging (fMRI) was used to examine the disruption to the connectivity of the important brain regions as a result of emotional interference.
Importantly, the study tested whether this emotional interference was specific to schizophrenia, or whether it was common across other psychotic disorders (in this case comparing it to bipolar disorder with psychosis).
The study found that individuals with schizophrenia showed worse accuracy in the task, as well as a reduction in connectivity between the amygdala and the medial prefrontal cortex, when compared with the other participants (the bipolar disorder with psychosis group did not differ from the control group). Therefore, reduced functional connectivity in these brain regions, when dealing with distracting emotional information, reflects a deficit that is specific to schizophrenia. Furthermore, the study found that this was related to other clinical deficits, such as restricted affect and diminished emotional range, along with unemployment.
Altogether, these findings highlight the potential for the connectivity between the amygdala and the medial prefrontal cortex to be a neural marker of schizophrenia.
