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7th World Congress of Biological Psychiatry, 1-6 July 2001, Berlin, Germany Symposium ERP and EEG Studies in Psychosis. Task Demand in Schizophrenia: Auditory Multichannel ERPs. Jürgen Kayser, Gerard E. Bruder, Craig E. Tenke. Department of Biopsychology. New York State
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7th World Congress of Biological Psychiatry, 1-6 July 2001, Berlin, Germany Symposium ERP and EEG Studies in Psychosis Task Demand in Schizophrenia: Auditory Multichannel ERPs Jürgen Kayser, Gerard E. Bruder, Craig E. Tenke Department of Biopsychology New York State Psychiatric Institute Columbia University College of Physicians and Surgeons Xavier F. Amador, Dolores Malaspina, Jack M. Gorman Department of Clinical Psychobiology
Temporal lobe abnormalities in schizophrenia • neocortical: superior temporal gyrus (e.g., Barta et al., 1990) • subcortical: hippocampus (e.g., Bogerts et al., 1990) Auditory ERP abnormalities in schizophrenia • early and late ERP components: N1, N2, MMN, P3 (e.g., Ford et al., 1994; Javitt et al., 1995) • slow wave ERP activity: CNV, PINV (e.g., Klein et al., 1996) Medial and lateral temporal lobe regions are involved in generation/ modulation of auditory ERPs (e.g., Knight et al., 1989; Menon et al., 1997) auditory N2 and P3 reductions in schizophrenia (e.g., McCarley et al., 1991, 1993; O’Donnell et al., 1993) Both structural and functional abnormalities in schizophrenia • affect primarily the left side (e.g., Barta et al., 1990; Falkai et al., 1995; Salisbury et al., 1998) left-sided, language-related deficit in the supratemporal plane (e.g., Crow, 1990) • affect both hemispheres (e.g., Weinberger et al., 1991; Pfefferbaum et al., 1989) Background
Most auditory ERP studies in schizophrenia relied on simple target detection (‘oddball’) tasks with pure tones lateralized temporal dysfunction in schizophrenia may be better studied by using • both simple and more demanding auditory tasks • stimuli that require a differential involvement of left and right hemispheric regions ERP measures can provide unique information about neurophysiological processes underlying cognitive dysfunctions in schizophrenia • sequence of ERP components reflects different aspects of information processing • (early sensory-attentional (e.g., N1) to late cognitive (e.g., P3)) temporal characteristics of the underlying cognitive deficits in schizophrenia • using an adequate spatial resolution to display and analyze ERP topographies identify brain regions associated with specific cognitive functions and dysfunctions Background (cont.)
‘Oddball’ Task Dichotic Listening Task 20% target 50% match 80% non-target 50% non-match dichotic binaural Left or Right Press ... ... ... ... ... ... binaural C ... ... Delayed Left or Right Press C C E E E E E C C G D Phonetic: CV Syllables dichotic binaural Left or Right Press binaural /da/ Delayed Left or Right Press /da/ /da/ /ka/ /da/ consonant-vowel syllables [/ba/, /da/, /ga/, /ka/, /pa/, /ta/] matched for discriminability /ka/ /da/ /ka/ /ba/ /ta/ /ka/ /ka/ Kayser et al (1998). Psychophysiology, 35:576-590. Kayser et al (2001). Biol Psychiatry, 49: 832-847. Bruder et al (1999). Arch Gen Psychichiatry, 56:267-276. Stimuli and Procedure Tonal: Complex Tones square waves [264 .. 485 Hz] corresponding to major notes
Demographic Data Patients (n=26) Controls (n=26) schizophrenia (n=19) schizoaffective (n=7) DSM-IV diagnosis BPRS 34.1 ±10.6 10 female 16 male 13 female 13 male Gender Age 33.2 ±10.9 35.5 ±11.7 Handedness (Oldfield, 1971) 84.7 ±24.7 84.8 ±12.8
Patients (n=26) Controls (n=26) Behavioral Data P = .003 P = .007 Percent Correct Tones Syllables Tones Syllables Oddball Task Dichotic Listening Task
------- Patients (n=26) ------- Controls (n=26) ERP Waveforms: Vertex N1 N1 N2 Tones Slow Wave Slow Wave P3 N1 N1 N2 Syllables Slow Wave Slow Wave P3 Oddball Task Dichotic Listening Task
ERP Topographies: Surface Potentials Time interval: 0 - 990 ms Oddball Task Dichotic Listening Task Tones Syllables Tones Syllables Controls (n = 26) Patients (n = 26)
Explained Variance S880 44.1% P410 36.8% N200 4.1% P280 3.5% N100 2.2% PCA Factor Loadings • covariance matrix • unscaled Varimax rotation N100 P280 N200 S880 P410
ERP Topographies: N100 N100 Oddball Task Dichotic Listening Task Controls (n = 26) Patients (n = 26) Tones Syllables Tones Syllables
ERP Topographies: N200 N200 Oddball Task Dichotic Listening Task Controls (n = 26) Patients (n = 26) Tones Syllables Tones Syllables
ERP Topographies: P280 P280 Oddball Task Dichotic Listening Task Controls (n = 26) Patients (n = 26) Tones Syllables Tones Syllables
ERP Topographies: P410 P410 Oddball Task Dichotic Listening Task Controls (n = 26) Patients (n = 26) Tones Syllables Tones Syllables
ERP Topographies: S880 S880 Oddball Task Dichotic Listening Task Controls (n = 26) Patients (n = 26) Tones Syllables Tones Syllables
ERP of controls were characterized by • stimulus-dependent N2 asymmetries, particularly for simple oddball tasks • enhanced N2 amplitude over the right lateral-temporal region for complex tones pitch discrimination (right frontotemporal) • enhanced N2 amplitude over the left parietal region for syllables phoneme discrimination (left parietotemporal) • N2 differences as a function of task demand automatic stimulus classification for simple target detection Summary • ERP components with maximum differences as a function of task demand were • N2-P3 complex: simple oddball tasks • late positive complex: more demanding dichotic listening tasks
Summary (cont.) • ERP of schizophrenic patients were characterized by • markedly reduced early negativities (N1, N2), particularly for simple oddball tasks • a failure to show stimulus-dependant N2 asymmetries • markedly reduced N2 differences as a function of task demand deficit in automatic stimulus classification • no reduction in P3 amplitude, particularly for simple tasks using tonal stimuli, • for which no performance deficits were observed schizophrenic patients may compensate for deficits in early automatic processing with more effortful processing when possible • no P3 asymmetry • asymmetrical reduction only with more severe illness? • asymmetrical functional reduction only with asymmetrical structural abnormalities? • reductions in late positive slow wave, independent of stimulus type and cognitive demand precise meaning unclear • left-lateralized reduction in late positivity / P3(00) ? • late asymmetric, response-related (?) negativities
Medication Status Oddball Task N1 N2 P3 Bruder et al (2001). Biol Psychiatry, in press.
Behavioral Asymmetry and N2 Asymmetry Bruder et al (1999). Arch Gen Psychiatry, 56:267-276.
P420 + P300 – N200 Behavioral Performance and ERP Amplitude Oddball Task Kayser et al (2001). Biol Psychiatry, 49: 832-847.
N1 N2 P3 Continuous Word Recognition Memory Kayser et al (1999). Int J Psychophysiol, 34: 249-265.
N2 N1 P3 Dot Enumeration Task Bruder et al (1998). J Abnorm Psychol, 107: 399-411.