title: Stimulus train duration but not attention moderates γ-band entrainment abnormalities in schizophrenia.
abstract: Electroencephalographic (EEG) studies of auditory steady-state responses (aSSRs) non-invasively probe gamma-band (40-Hz) oscillatory capacity in sensory cortex with high signal-to-noise ratio. Consistent reports of reduced 40-Hz aSSRs in persons with schizophrenia (SZ) indicate its potential as an efficient biomarker for the disease, but studies have been limited to passive or indirect listening contexts with stereotypically short (500ms) stimulus trains. An inability to modulate sensorineural processing in accord with behavioral goals or within the sensory environmental context may represent a fundamental deficit in SZ, but whether and how this deficit relates to reduced aSSRs is unknown. We systematically varied stimulus duration and attentional contexts to further mature the 40-Hz aSSR as biomarker for future translational or mechanistic studies. Eighteen SZ and 18 healthy subjects (H) were presented binaural pure-tones with or without sinusoidal amplitude modulation at 40-Hz. Stimulus duration (500-ms or 1500-ms) and attention (via a button press task) were varied across 4 separate blocks. Evoked potentials recorded with dense-array EEGs were analyzed in the time-frequency domain. SZ displayed reduced 40-Hz aSSRs to typical stimulation parameters, replicating previous findings. In H, aSSRs were reduced when stimuli were presented in longer trains and were slightly enhanced by attention. Only the former modulation was impaired in SZ and correlated with sensory discrimination performance. Thus, gamma-band aSSRs are modulated by both attentional and stimulus duration contexts, but only modulations related to physical stimulus properties are abnormal in SZ, supporting its status as a biomarker of psychotic perceptual disturbance involving non-attentional sensori-cortical circuits.
authors: Department of Psychology and Neuroscience, BioImaging Research Center, University of Georgia, Athens, GA, United States.
authors: Jordan P
authors: JP
authors: Hamm
authors: Department of Psychology and Neuroscience, BioImaging Research Center, University of Georgia, Athens, GA, United States.
authors: Anastasia M
authors: AM
authors: Bobilev
authors: Department of Psychology and Neuroscience, BioImaging Research Center, University of Georgia, Athens, GA, United States.
authors: Lauren K
authors: LK
authors: Hayrynen
authors: Department of Psychology and Neuroscience, BioImaging Research Center, University of Georgia, Athens, GA, United States.
authors: Matthew E
authors: ME
authors: Hudgens-Haney
authors: Department of Psychology and Neuroscience, BioImaging Research Center, University of Georgia, Athens, GA, United States.
authors: William T
authors: WT
authors: Oliver
authors: Department of Psychology and Neuroscience, BioImaging Research Center, University of Georgia, Athens, GA, United States.
authors: David A
authors: DA
authors: Parker
authors: Department of Psychology and Neuroscience, BioImaging Research Center, University of Georgia, Athens, GA, United States.
authors: Jennifer E
authors: JE
authors: McDowell
authors: Department of Psychiatry, Georgia Reagents University, Medical College of Georgia, Augusta, GA, United States.
authors: Peter A
authors: PA
authors: Buckley
authors: Department of Psychology and Neuroscience, BioImaging Research Center, University of Georgia, Athens, GA, United States. Electronic address: clementz@uga.edu.
authors: Brett A
authors: BA
authors: Clementz
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000209:etiology*; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology / Q000528:radiation effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D025341:Principal Component Analysis; D011571:Psychoacoustics; D011930:Reaction Time; D012559:Schizophrenia / Q000150:complications*; D013997:Time Factors
keywords: Attention; Auditory; Electroencephalography; Gamma; Steady-state