title: Atypical antipsychotics normalize low-gamma evoked oscillations in patients with schizophrenia.
abstract: The symptoms of schizophrenia might be mediated by a cortical network disconnection which may disrupt the cortical oscillatory activity. Steady-state responses are an easy and consistent way to explore cortical oscillatory activity. A chirp-modulated tone (increasing the frequency of the modulation in a linear manner) allows a fast measure of the steady-state response to different modulation rates. With this approach, we studied the auditory steady-state responses in two groups of patients with schizophrenia (drug-naive and treated with atypical antipsychotic drugs), in order to assess the differences in their responses with respect to healthy subjects, and study any potential effect of medication. Drug-naive patients had reduced amplitude and inter-trial phase coherence of the response in the 30-50Hz range, and reduced amplitude of the response in the 90-100Hz range, when compared to controls. In the treated patients group, the response in the 30-50Hz range was normalized to values similar to the control group, but the reduction in amplitude in the 90-100Hz range remained as in the drug-naive group. These results suggest that gamma activity impairment in schizophrenia is a complex phenomenon that affects a wide band of frequencies and may be influenced by antipsychotic treatment.
authors.affiliation: Clinical Neurophysiology Section, Clínica Universidad de Navarra, Pamplona, Spain; Neurophysiology Laboratory, CIMA (Centre for Applied Medical Research) Universidad de Navarra, Pamplona, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Alegre
authors.affiliation: Department of Psychiatry, Clínica Universidad de Navarra, Pamplona, Spain.
authors.forename: Patricio
authors.initials: P
authors.lastname: Molero
authors.affiliation: Neurophysiology Laboratory, CIMA (Centre for Applied Medical Research) Universidad de Navarra, Pamplona, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Valencia
authors.affiliation: Department of Psychiatry, Clínica Universidad de Navarra, Pamplona, Spain.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Mayner
authors.affiliation: Department of Psychiatry, Clínica Universidad de Navarra, Pamplona, Spain.
authors.forename: Felipe
authors.initials: F
authors.lastname: Ortuño
authors.affiliation: Clinical Neurophysiology Section, Clínica Universidad de Navarra, Pamplona, Spain; Neurophysiology Laboratory, CIMA (Centre for Applied Medical Research) Universidad de Navarra, Pamplona, Spain. Electronic address: jartieda@unav.es.
authors.forename: Julio
authors.initials: J
authors.lastname: Artieda
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D014150:Antipsychotic Agents / Q000494:pharmacology*; D004569:Electroencephalography / Q000379:methods; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D005260:Female; D065818:Gamma Rhythm / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012559:Schizophrenia / Q000188:drug therapy / Q000503:physiopathology*; D012565:Schizophrenic Psychology
chemical_list: D014150:Antipsychotic Agents
keywords: Antipsychotic treatment; Oscillatory activity; Schizophrenia; Steady-state responses