Striatum is one of the key brain regions of the cortico-striato-thalamo-cortical loops accounting for the behavioural, cognitive and motor dysfunctions observed in patients with schizophrenia.
Recent meta-analysis also confirms the increased pre-synaptic dopamine synthesis in the striatum in patients with schizophrenia and even in at-risk individuals with schizotypal traits.
Drs. WANG Yi and Raymond Chan from the Neuropsychology and Applied Cognitive Neuroscience (NACN) Laboratory and the CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences have previously shown that individuals with schizotypal traits have already exhibited altered striato-cortical functional connectivity.
In particular, individuals with social anhedonia showed hyper-connectivity between dorsal striatum and motor cortex, and ventral striatum and anterior cingulate cortex and insular compared to those without social anhedonia. However, these findings were limited to a relatively small sample with social anhedonia.
The observed findings cannot generalize to the overall construct of schizotypy that also comprises individuals with positive schizotypy and disorganization dimensions.
In order to revisit this striato-cortical connectivity impairment in individuals with schizotypal traits, Drs. WANG and Chan, together with Prof. Ulrich Ettinger Germany have administered the measure of schizotypal traits to 111 participants from the general public.
They also invited these participants to undertake a resting-state brain scan. They examined specifically six striatal seed regions in both hemispheres using resting-state functional connectivity analysis. Moreover, lateralization indices were also estimated to examine if there was asymmetry pattern associated with schizotypal traits.
Their findings showed that the positive dimension of schizotypy were significantly correlated with resting-state functional connectivity between ventral striatum and frontal cortex and inversely correlated with resting-state connectivity between dorsal striatum and posterior cingulate. However, they did not find any significant correlations between negative dimension schizotypy and striato-cortical resting-state connectivity.
More interestingly, there were significant correlations found between schizotypy scores and lateralization index of right dorsal caudate and right rostral putamen.
Taken together, these findings not only reconfirm the impaired striato-cortical connectivity observed in individuals with schizotypal traits, but extend further to show the asymmetry of such altered connectivity is associating with these traits.
This study was supported by grants from the National Basic Research Programme of China (Precision Psychiatry Programme), the Beijing Training Project for Leading Talents in S&T, the Beijing Municipal Science & Technology Commission Grant, the National Science Fund China, and the DFG grant Et 31/2-1.
This paper is now available online in Human Brain Mapping.
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