Mismatch negativity and low frequency oscillations in schizophrenia families

Objective: Theta-alpha range oscillations have been associated with MMN in healthy controls. Our previous studies showed that theta-alpha activities are highly heritable in schizophrenia patients' families. We aimed to test the hypothesis that theta-alpha activities may contribute to MMN in schizophrenia patients and their family members. Methods: We compared MMN and single trial oscillations during MMN in 95 patients, 75 first-degree relatives, 87 controls, and 34 community subjects with schizophrenia spectrum personality (SSP) traits. Results: We found that (1) MMN was reduced in patients (p < 0.001) and SSP subjects (p = 0.047) but not in relatives (p = 0.42); (2) there were augmented 1-20 Hz oscillations in patients (p = 0.02 to < 0.001) during standard and deviant stimuli; (3) theta-alpha (5-12 Hz) oscillations had the strongest correlation to MMN in controls and relatives (Delta R-2 = 21.4-23.9%, all p < 0.001), while delta (< 5 Hz) showed the strongest correlation to MMN in schizophrenia and SSP trait subjects; and, (4) MMN (h(2) = 0.56, p = 0.002) and theta-alpha (h(2) = 0.55, p = 0.004) were heritable traits. Conclusions: Low frequency oscillations have a robust relationship with MMN and the relationship appears altered by schizophrenia; and schizophrenia patients showed augmented low frequency activities during the MMN paradigm. Significance: The results encourage investigation of low frequency oscillations to elucidate the neurophysiological pathology underlying MMN abnormalities in schizophrenia. (C) 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.