M50 sensory gating predicts negative symptoms in schizophrenia Robert J. Thoma a,b,c, * , Faith M. Hanlon a,b , Sandra N. Moses b , Daniel Ricker b , Mingxiong Huang h , Christopher Edgar e , Jessica Irwin a , Fernando Torres a , Michael P. Weisend b,d , Lawrence E. Adler f , Gregory A. Miller c,e,g , Jose M. Canive a,c, * a Psychiatry Service, New Mexico VA Health Care System, Albuquerque, NM 87108, United States b Department of Psychology, University of New Mexico, Albuquerque, NM 87108, United States c Department of Psychiatry, University of New Mexico Health Sciences Center, Albuquerque, NM 87108, United States d Department of Radiology, New Mexico VA Health Care System, Albuquerque, NM 87108, United States e Department of Psychology and Beckman Institute Biomedical Imaging Center, University of Illinois at Urbana-Champaign, Urbana, IL, United States f Psychiatry Service, Denver VAMC and Department of Psychiatry, University of Colorado Health Sciences Center, Denver, CO, United States g Department of Psychiatry, University of Illinois at Urbana-Champaign, Urbana, IL, United States h Department of Radiology, University of California, San Diego, CA, United States Availble online 20 August 2004 Abstract Impaired auditory sensory gating is considered characteristic of schizophrenia and a marker of the information processing deficit inherent to that disorder. Predominance of negative symptoms also reflects the degree of deficit in schizophrenia and is associated with poorer pre-morbid functioning, lower IQ, and poorer outcomes. However, a consistent relationship between auditory sensory gating and negative symptoms in schizophrenia has yet to be demonstrated. The absence of such a finding is surprising, since both impaired auditory gating and negative symptoms have been linked with impaired fronto-temporal cortical function. The present study measured auditory gating using the P50 event related potential (ERP) in a paired-click paradigm and capitalized on the relative localization advantage of magnetoencephalography (MEG) to assess auditory sensory gating in terms of the event related field (ERF) M50 source dipoles on bilateral superior temporal gyrus (STG). The primary hypothesis was that there would be a positive correlation between lateralized M50 auditory sensory gating measures and negative symptoms in patients with schizophrenia. A standard paired-click paradigm was used during simultaneous EEG and MEG data collection to determine S2/S1 sensory gating ratios in a group of 20 patients for both neuroimaging techniques. Participants were administered the Schedule for the Assessment of Negative Symptoms (SANS), the Positive and Negative Symptom Scale (PANSS), and the Calgary Depression Scale for Schizophrenia. Consistent with previous reports, there was no relationship between ERP P50 sensory gating and negative symptoms. However, right (not left) hemisphere ERF M50 sensory gating ratio was significantly and 0920-9964/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.schres.2004.07.001 * Corresponding authors. Robert J. Thoma and Jose M. Canive is to be contacted at The New Mexico VA Health Care System VAMC/ 116A, 1501 San Pedro SE, Albuquerque, NM 87108, United States. Tel.: +1 505 265 1711x5135; fax: +1 505 256 5474. E-mail address: robert.thoma@med.va.gov (R.J. Thoma). Schizophrenia Research 73 (2005) 311 – 318 www.elsevier.com/locate/schres