title: Neural activations during auditory oddball processing discriminating schizophrenia and psychotic bipolar disorder.
abstract: BACKGROUND
  Reduced amplitude of the P300 event-related potential in auditory oddball tasks may characterize schizophrenia (SZ) but is also reported in bipolar disorder. Similarity of auditory processing abnormalities between these diagnoses is uncertain, given the frequent combination of both psychotic and nonpsychotic patients in bipolar samples; abnormalities may be restricted to psychosis. In addition, typically only latency and amplitude of brain responses at selected sensors and singular time points are used to characterize neural responses. Comprehensive quantification of brain activations involving both spatiotemporal and time-frequency analyses could better identify unique auditory oddball responses among patients with different psychotic disorders.
  
  
  METHODS
  Sixty SZ, 60 bipolar I with psychosis (BPP), and 60 healthy subjects (H) were compared on neural responses during an auditory oddball task using multisensor electroencephalography. Principal components analysis was used to reduce multisensor data before evaluating group differences on voltage and frequency of neural responses over time.
  
  
  RESULTS
  Linear discriminant analysis revealed five variables that best differentiated groups: 1) late beta activity to standard stimuli; 2) late beta/gamma activity to targets discriminated BPP from other groups; 3) midlatency theta/alpha activity to standards; 4) target-related voltage at the late N2 response discriminated both psychosis groups from H; and 5) target-related voltage during early N2 discriminated BPP from H.
  
  
  CONCLUSIONS
  Although the P300 significantly differentiated psychotic groups from H, it did not uniquely discriminate groups beyond the above variables. No variable uniquely discriminated SZ, perhaps indicating utility of this task for studying psychosis-associated neurophysiology generally and BPP specifically.
authors.affiliation: Department of Psychology, BioImaging Research Center, University of Georgia, Athens, Georgia, USA.
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Ethridge
authors.forename: Jordan P
authors.initials: JP
authors.lastname: Hamm
authors.forename: John R
authors.initials: JR
authors.lastname: Shapiro
authors.forename: Ann T
authors.initials: AT
authors.lastname: Summerfelt
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Keedy
authors.forename: Michael C
authors.initials: MC
authors.lastname: Stevens
authors.forename: Godfrey
authors.initials: G
authors.lastname: Pearlson
authors.forename: Carol A
authors.initials: CA
authors.lastname: Tamminga
authors.forename: Nash N
authors.initials: NN
authors.lastname: Boutros
authors.forename: John A
authors.initials: JA
authors.lastname: Sweeney
authors.forename: Matcheri S
authors.initials: MS
authors.lastname: Keshavan
authors.forename: Gunvant
authors.initials: G
authors.lastname: Thaker
authors.forename: Brett A
authors.initials: BA
authors.lastname: Clementz
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods / Q000523:psychology; D000293:Adolescent; D000328:Adult; D001307:Auditory Perception / Q000502:physiology; D001714:Bipolar Disorder / Q000503:physiopathology* / Q000523:psychology; D058256:Brain Waves / Q000502:physiology*; D016002:Discriminant Analysis; D004569:Electroencephalography / Q000379:methods / Q000523:psychology; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D025341:Principal Component Analysis / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013997:Time Factors