Kayako Matsuo1, S.H. Annabel Chen2, Chih-Min Liu3, Chen-Chung Liu3, Hai-Go Hwu3, Wen-Yih I. Tseng1
1National Taiwan University College of Medicine, Taipei, Taiwan; 2Division of Psychology, Nanyang Technological University, Singapore; 3Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan
We investigated influences of various covariates on a verbal working memory (VWM) fMRI employing 18 each of schizophrenia and control participants. Six covariates of age, gender, response time (RT), accuracy rate, handedness score, and education year had all no significant differences between the two subject groups. Covariates by the behavioral data (RT and accuracy) specifically showed positive correlations with the DMN activation, which reflect the self-regulating mechanism during the low load condition. The inclusion of covariates into the design matrix was effective to obtain the “true” contrast effects even when the comparison groups were “matched” beforehand.