Article

P3 and delta band responses in visual oddball paradigm in schizophrenia

Department of Physiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
Neuroscience Letters (Impact Factor: 2.03). 09/2008; 440(3):304-8. DOI: 10.1016/j.neulet.2008.05.054
Source: PubMed

ABSTRACT

Amplitude reduction of the oddball P3 wave is a well-replicated but non-specific finding of schizophrenia. The time-frequency analysis of single-trial ERP data allows to specify in a reliable manner whether the P3 reduction in schizophrenia is due to the decreased P3 response in single trials or due to the inter-trial variability in the timing of the response. Since the delta response most strongly contributes to the P3 amplitude, we focused to the low frequency range of the time-frequency transformed data. EEG was recorded from chronic schizophrenia patients and matched healthy controls during a simple visual oddball task. The wavelet transforms of the averaged ERP and the single trials were computed to investigate the amplitudes of the evoked (phase-locked) and total (phase-locked+non-phase-locked) delta (1-3 Hz) responses, respectively. Evoked delta activity and P3 amplitude to target stimuli were both reduced significantly in patients with schizophrenia, whereas no such difference was obtained for the total delta activity. The significant reduction of the evoked delta response and the absence of such a difference in the total delta response of schizophrenia patients reveals that the delta band response is weakly phase-locked to stimulus in schizophrenia. This result suggests that the reduced P3 amplitudes in the averaged ERPs of schizophrenia patients result from a temporal jitter in the activation of neural circuits engaged in P3 generation.

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    • "They thus assess voltage changes that are time-locked to the event of interest, that is, the rare target stimulus.By averaging across a large number of EEG epochs,ongoing brain activity—pre-and post-stimulus oscillations with phase independent from stimulus events—cancels out in the long run, increasing the relative strength of stimulus-evoked potentials. These event-related potentials (ERPs) consist of a series of positive and negative peaks occurring at a fixed time relative to the event (Ergen et al., 2008; Gilmore et al., 2010a; Ucles et al., 2009). The procedure assumes that ongoing oscillatory EEG activityare background ''noise'' in which the ERP ''signal'' is embedded. "
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    ABSTRACT: Stimuli in simple oddball target detection paradigms cause evoked responses in brain potential. These responses are heritable traits, and potential endophenotypes for clinical phenotypes. These stimuli also cause responses in oscillatory activity, both evoked responses phase-locked to stimulus presentation and phase-independent induced responses. Here, we investigate whether phase-locked and phase-independent oscillatory responses are heritable traits. Oscillatory responses were examined in EEG recordings from 213 twin pairs (91 monozygotic and 122 dizygotic twins) performing a visual oddball task. After group Independent Component Analysis (group-ICA) and time-frequency decomposition, individual differences in evoked and induced oscillatory responses were compared between MZ and DZ twin pairs. Induced (phase-independent) oscillatory responses consistently showed the highest heritability (24–55%) compared to evoked (phase-locked) oscillatory responses and spectral energy, which revealed lower heritability at 1–35.6% and 4.5–32.3%, respectively. Since the phase-independent induced response encodes functional aspects of the brain response to target stimuli different from evoked responses, we conclude that the modulation of ongoing oscillatory activity may serve as an additional endophenotype for behavioral phenotypes and psychiatric genetics.
    Full-text · Article · Dec 2015 · Biological Psychology
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    • "The patients revealed less evoked delta response than controls for correct–reject trials. The results of Ergen et al. (2008) and Bates et al. (2009) "
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    ABSTRACT: In the last decade, the brain's oscillatory responses have invaded the literature. The studies on delta (0.5-3.5Hz) oscillatory responses in humans upon application of cognitive paradigms showed that delta oscillations are related to cognitive processes, mainly in decision making and attentional processes. The present manuscript comprehensively reviews the studies on delta oscillatory responses upon cognitive stimulation in healthy subjects and in different pathologies, namely Alzheimer's disease, Mild Cognitive Impairment (MCI), bipolar disorder, schizophrenia and alcoholism. Further delta oscillatory response upon presentation of faces, facial expressions, and affective pictures are reviewed. The relationship between pre-stimulus delta activity and post-stimulus evoked and event-related responses and/or oscillations are discussed. Cross-frequency couplings of delta oscillations with higher frequency windows are also included in the review. The conclusion of this review includes several important remarks, including that delta oscillatory responses are involved in cognitive and emotional processes. A decrease of delta oscillatory responses could be a general electrophysiological marker for cognitive dysfunction (Alzheimer's disease, MCI, bipolar disorder, schizophrenia and alcoholism). The pre-stimulus activity (phase or amplitude changes in delta activity) has an effect on post-stimulus EEG responses. Copyright © 2015. Published by Elsevier B.V.
    Full-text · Article · Feb 2015 · International journal of psychophysiology: official journal of the International Organization of Psychophysiology
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    • "One of the common parameters seen in ERO studies in different pathologies is the decrease in delta activity upon cognitive load (Başar and Güntekin, 2013). Previous studies related to brain pathological states indicate that the amplitude of event-related delta oscillations decreases in Alzheimer's disease (Yener et al., 2008), mild cognitive impairment (Kurt et al., 2014; Yener et al., 2013), schizophrenia (Ergen et al., 2008; Ford et al., 2008), bipolar disorder (Atagün et al., 2014) and alcoholism (Kamarajan et al., 2004). However, there are few studies in the literature investigating delta ERO in healthy elderly (Schmiedt-Fehr and Başar-Eroglu, 2011; Schmiedt-Fehr et al., 2011). "
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    ABSTRACT: The purpose of this study was to investigate changes in delta event-related oscillations (ERO) in younger and older healthy elderly subjects. We hypothesized that delta ERO were affected by age-related changes, which could be reflected in a visual oddball paradigm. The study included two groups of subjects, 17 younger healthy elderly (mean age: 63.1±2.8years) and 17 gender- and education- matched older healthy elderly (mean age: 79.6±5.2years), who performed a visual oddball paradigm. EEG was recorded from F3, Fz, F4, C3, Cz, C4, P3, Pz, P4, O1, Oz and O2 locations. Peak-to-peak amplitude of delta (0.5-3Hz) target ERO responses during the post-stimulus 0-800msec time window were measured. Repeated measures of ANOVA was used to analyze four locations (frontal, central, parietal, occipital), at three sagittal (left, midline, right) sites. Independent t-tests were applied for post-hoc analyses. The older healthy elderly group had 16-25% lower values for the maximum peak-to-peak amplitudes of delta ERO compared with the younger healthy elderly group over frontal (p<0.003), central (p<0.0001) and parietal (p<0.007) locations [F3.96=4.396, p=0.015]. Furthermore, there was a moderate negative correlation between age and Cz peak-to-peak amplitude of target delta responses [r=-0.401, p<0.02], indicating the notion that peak-to-peak amplitude of Cz decreases as age increases. In the present study younger healthy elderly showed significantly higher event-related delta responses than older healthy elderly at frontal, central and parietal locations. Moreover, delta ERO responses decreased in accordance with age. Copyright © 2015. Published by Elsevier B.V.
    Full-text · Article · Feb 2015 · International journal of psychophysiology: official journal of the International Organization of Psychophysiology
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