Amygdala Function, Blood Flow, and Functional Connectivity in Nonclinical Schizotypy

Abstract

Background and Hypothesis Schizotypy can be utilized as a phenotypic risk marker for schizophrenia and its spectrum and might relate to putative dimensional biological markers of the psychosis spectrum. Among these are amygdala function and structure, which are impaired in schizophrenia, but possibly also correlated with subclinical expression of schizotypy in nonclinical samples. We tested whether different parameters relating to amygdala function would be different in healthy subjects with relatively higher vs lower schizotypy traits. Study Design Sixty-three psychiatrically healthy subjects (42 with higher vs 21 with lower schizotypy scores, selected on the basis of the Oxford-Liverpool Inventory of Feelings and Experiences positive schizotypy subscale) underwent a multimodal imaging protocol, including functional magnetic resonance imaging (fMRI) during a task-based emotional (fearful) face recognition paradigm, arterial spin labeling for measurement of regional cerebral blood flow (rCBF) at rest, and resting-state fMRI for functional connectivity (FC) analyses, as well as a T1-weighted structural MRI scan. Study Results The high schizotypy group showed significantly higher right amygdala activation during viewing of fearful emotional images and lower resting-state FC of the left amygdala with a cerebellum cluster, but no differences in resting-state amygdala rCBF or volume. Conclusions Our findings demonstrate a functionally relevant effect of schizotypy on amygdala activation in the absence of baseline rCBF or macroscopic structure. This suggests that while schizotypy might affect some functional or structural parameters in the brain, certain functionally relevant effects only emerge during cognitive or emotional triggers.