Association of schizotypy with striatocortical functional connectivity and its asymmetry in healthy adults

Abstract

Altered striatocortical functional connectivity has been suggested to be a trait marker of schizophrenia spectrum disorders, including schizotypal personality. In the present study, we examined the association between schizotypal personality traits and striatocortical functional connectivity in a sample of healthy adults. The German version of the Schizotypal Personality Questionnaire was obtained from N = 111 participants recruited from the general public. Resting-state functional magnetic resonance imaging scans were acquired at 3T. Six striatal seed regions in each hemisphere were defined and striatocortical resting-state functional connectivity (rsFC) as well as its lateralization indices was calculated. Regression analysis showed that schizotypy scores, especially from the positive dimension, were positively correlated with rsFC between ventral striatum and frontal cortex and negatively associated with rsFC between dorsal striatum and posterior cingulate. No significant associations were found between negative dimension schizotypy and striatocortical rsFC. We also found positive correlations between schizotypy total scores and lateralization index of right dorsal caudate and right rostral putamen. In conclusion, the present study extends previous evidence of altered striatocortical rsFC in the schizophrenia spectrum. The observed associations resemble in part the alterations observed in psychotic patients and their relatives, providing support for dimensionality from schizotypal personality to the clinical disorder. Hum Brain Mapp 39:288-299, 2018. © 2017 Wiley Periodicals, Inc.

Keywords: connectivity; functional magnetic resonance imaging; lateralization; resting state; schizotypy; striatum.

Figure 1

Associations of SPQ total and dimension scores with striatocortical functional connectivity. (A) The clusters with significant correlations with SPQ total scores. (B) The clusters with significant correlations with the SPQ cognitive‐perceptual factor. (C) Clusters with significant correlations with the SPQ disorganized dimension. All regression analyses included age, verbal IQ and mean FD as covariates. Thresholds for significance were set as Cluster Defining Threshold (CDT) of P < 0.001 and cluster P FWE corrected < 0.05 and cluster size k ≥ 30 voxels.

Figure 2

Asymmetry Index of functional connectivity of all seed regions. Asymmetry Index (AI) of functional connectivity of each seed was calculated using the following equation: AI = N _i/H _i – N _c/H _c, where N _i and N _c are the numbers of voxels strongly correlated (threshold at r > 0.25) with the seed in the ipsilateral and contralateral hemispheres, respectively, and H _i and H _c are the total number of voxels in the ipsilateral and contralateral hemispheres, respectively. VSi, ventral striatum inferior/nucleus accumbens; VSs, ventral striatum superior; DC, dorsal caudate; DCP, dorsal caudal putamen; DRP, dorsal rostral putamen; VRP, ventral rostral putamen. The error bars indicate the standard errors.