Patients with schizophrenia report diminished pleasure when looking forward to future events. This reduced ability to envision and predict future events and episodes is one of the core features of negative symptoms known as anticipatory pleasure deficit. Such deficit is often refractory to conventional medical treatment and has a negative impact on the everyday functioning of patients with schizophrenia. Recent studies suggest that this impairment is also observed in individuals with high level of social anhedonia. However, the neural mechanism underlying this impairment is not clearly understood.
Dr. Raymond Chan and his team from the Institute of Psychology of the Chinese Academy of Sciences have conducted a study to examine specifically the neural correlates of envisioning positive future events in individuals with high levels of social anhedonia.
They recruited 49 individuals with high levels of social anhedonia and 33 individuals with low levels of social anhedonia to undertake a functional imaging task inside the scanner. All the participants were requested to envision positive or neutral future events according to a set of cue words inside the scanner.
Their findings showed that reduced activation at the caudate and the precuneus were found when individuals with high levels of social anhedonia were anticipating positive (vs. neutral) future events.
These individuals also exhibited increased functional connectivity between the caudate and the inferior occipital gyrus during positive (vs. neutral) anticipation. However, both individuals with high and low levels of social anhedonia exhibited a similar pattern of brain activation for the construction vs. elaboration contrast, regardless of the emotional context.
Taken together, these findings show that individuals with high levels of social anhedonia exhibited altered activation and functional connectivity when they were envisioning positive future events comparing to those individuals with low levels of social anhedonia.
The findings also highlight the important role of altered cortico-striatal connectivity upon anticipatory pleasure deficits observed in individuals with high levels of social anhedonia.
This study is now published online in Psychological Medicine entitled "Altered activation and functional connectivity in individuals with social anhedonia when envisioning positive future episodes."
The study was supported by the National Key Research and Development Programme, the National Natural Science Foundation China, and the CAS Key Laboratory of Mental Health of the Institute of Psychology.
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