Memory impairment in schizophrenia: a study using event-related potentials in implicit and explicit tasks

Guillem, François; Bicu, Monica; Hooper, Ron; Bloom, D. M.; Wolf, Marc-Alain; Messier, Jacques; Desautels, René; Debruille, J. Bruno

doi:10.1016/s0165-1781(01)00305-5

Cited by 55 publications

(23 citation statements)

References 52 publications

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“…Kiang and Kutas (2005) found that individuals high in schizotypy showed larger (i.e., more negative) N400s to both high-and low-typicality exemplars, suggesting lower than normal activation of stimuli semantically related to the preceding category names; they also found smaller (i.e., less negative) N400s to non-exemplars, indicating higher than normal activation of unrelated items. The second aspect of the contextual deficit hypothesis is that schizophrenic patients might be less able to utilise semantic information from the previous encoding phase to modify the latency of their responses to repeated stimuli (Guillem et al, 2001;Jeong & Kubicki, 2010;Matsuoka et al, 1999). For example, the schizophrenic patients tested by Matsuoka and colleagues (1999) did not show significant changes in the amplitude of the N400s associated with repeated words in a semantic categorisation task.…”

Section: Discussionmentioning

confidence: 99%

Is conceptual implicit memory impaired in schizophrenia? Evidence from lexical decision and category verification

Marques

Spataro

Cestari

et al. 2014

Cognitive Neuropsychiatry

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Section: Discussionmentioning

confidence: 99%

Is conceptual implicit memory impaired in schizophrenia? Evidence from lexical decision and category verification

Marques

Spataro

Cestari

et al. 2014

Cognitive Neuropsychiatry

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“…One meta-analysis found that non-word stimuli yielded even larger effect sizes of compromised recognition memory performance in schizophrenia (Pelletier et al, 2005), and old/new ERP abnormalities in schizophrenia have been reported for unfamiliar faces that are difficult to verbalize (Guillem et al, 2001). To further address these issues of material specificity in a within-subjects design, we are now recording ERPs of larger samples of schizophrenia patients and healthy adults during continuous recognition memory tasks using both words and unfamiliar faces.…”

Section: Discussionmentioning

confidence: 99%

“…Guillem et al (2001) studied ERP old/new effects in 15 schizophrenia patients and 15 healthy controls during a continuous recognition memory paradigm with unfamiliar faces under implicit (indicate the gender) and explicit (item previously presented) task instructions. Using a 13-channel EEG montage referenced to the right ear lobe, reduced old/new effects were reported in patients over medial parietal sites for the implicit task at about 300 ms, overlapping a relative negative ERP deflection (N300), but not at about 500 ms, overlapping a late positive complex (P500).…”

Section: Introductionmentioning

confidence: 99%

“…Kayser and Tenke, 2003, 2005). All studies reviewed in the previous section differ in this regard, for instance, ranging from baseline-to-peak amplitude measures within certain time intervals (Baving et al, 2000), including individual peak identification used to determine individual time windows for amplitude integrals (Guillem et al, 2001) and fixed, sequential time window amplitudes at a priori determined sites covering regions-of-interest (Tendolkar et al, 2002), to data-driven ERP components measures derived from temporal principal components analysis (PCA; Kayser et al, 1999). It is not unreasonable to suspect that these different analytic approaches may themselves have led to different results and conclusions when applied to the same data.…”

Section: Introductionmentioning

confidence: 99%

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Stimulus- and response-locked neuronal generator patterns of auditory and visual word recognition memory in schizophrenia

Kayser

Tenke

Gil

et al. 2009

International Journal of Psychophysiology

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Examining visual word recognition memory (WRM) with nose-referenced EEGs, we reported a preserved ERP 'old-new effect' (enhanced parietal positivity 300-800 ms to correctly-recognized repeated items) in schizophrenia . However, patients showed reduced early negative potentials (N1, N2) and poorer WRM. Because group differences in neuronal generator patterns (i.e., sink-source orientation) may be masked by choice of EEG recording reference, the current study combined surface Laplacians and principal components analysis (PCA) to clarify ERP component topography and polarity and to disentangle stimulus-and response-related contributions. To investigate the impact of stimulus modality, 31-channel ERPs were recorded from 20 schizophrenic patients (15 male) and 20 age-, gender-, and handedness-matched healthy adults during parallel visual and auditory continuous WRM tasks. Stimulus-and response-locked reference-free current source densities (spherical splines) were submitted to unrestricted Varimax-PCA to identify and measure neuronal generator patterns underlying ERPs. Poorer (78.2±18.7% vs. 87.8±11.3% correct) and slower (958±226 vs. 773±206 ms) performance in patients was accompanied by reduced stimulus-related left parietal P3 sources (150 ms pre-response) and vertex N2 sinks (both overall and old/new effects) but modality-specific N1 sinks were not significantly reduced. A distinct mid-frontal sink 50-ms post-response was markedly attenuated in patients. Reductions were more robust for auditory stimuli. However, patients showed increased lateral-frontotemporal sinks (T7 maximum) concurrent with auditory P3 sources. Electrophysiologic correlates of WRM deficits in schizophrenia suggest functional impairments of posterior cortex (stimulus representation) and anterior cingulate (stimulus categorization, response monitoring), primarily affecting memory for spoken words.

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“…The N400 appears to be abnormal in schizophrenia (Koyama et al 1991;Niznikiewicz et al 1999;Sitnikova et al 2002), especially as thought disorder or cognitive disorganization increases (Andrews et al 1993). P600 amplitude is also smaller in schizophrenia patients than in controls, although schizophrenia patients who frequently experience reality distortion (i.e., hallucinations and delusions) show significantly larger (i.e., relatively more intact) P600 amplitudes than schizophrenia patients who do not experience prominent reality distortion (Guillem et al 2001;2003). Thus, the P600 effect is consistent with P&S's interpretation of gamma in schizophrenia, which is also thought to reflect episodic binding and is less impaired in schizophrenia patients who frequently experience reality distortion.…”

Section: Guarding Against Over-inclusive Notionsmentioning

confidence: 90%

Convergence of biological and psychological perspectives on cognitive coordination in schizophrenia

Phillips¹,

Silverstein²

2003

Behav Brain Sci

378

314

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Cognitive neuroscience provides a new conceptual framework for psychiatry by showing how psychological processes arise from neuronal activity (Kandel 1998). Conversely, it is possible that psychiatry will influence the future development of cognitive neuroscience by encouraging a better balance between localist and holistic conceptions of brain function. An apparent conflict between these conceptions has been central to the development of neuroscience, with the emphasis upon locally specialized functions emerging as clearly dominant. Neuroanatomy, neurophysiology, neuropsychology, and neuroimaging all show that different regions of the brain process information about different things, and that different cells within regions deal with different aspects of those things. Recent developments in experimental and theoretical neurobiology, however, are leading to an increased emphasis upon interactions that coordinate the activity of locally specialized processors. Here we argue that impairment of these coor-BEHAVIORAL AND BRAIN SCIENCES (2003) Abstract:The concept of locally specialized functions dominates research on higher brain function and its disorders. Locally specialized functions must be complemented by processes that coordinate those functions, however, and impairment of coordinating processes may be central to some psychotic conditions. Evidence for processes that coordinate activity is provided by neurobiological and psychological studies of contextual disambiguation and dynamic grouping. Mechanisms by which this important class of cognitive functions could be achieved include those long-range connections within and between cortical regions that activate synaptic channels via NMDAreceptors, and which control gain through their voltage-dependent mode of operation. An impairment of these mechanisms is central to PCP-psychosis, and the cognitive capabilities that they could provide are impaired in some forms of schizophrenia. We conclude that impaired cognitive coordination due to reduced ion flow through NMDA-channels is involved in schizophrenia, and we suggest that it may also be involved in other disorders. This perspective suggests several ways in which further research could enhance our understanding of cognitive coordination, its neural basis, and its relevance to psychopathology.Keywords: attention; cerebral cortex; cognitive coordination; cognitive neuropsychiatry; cognitive neuropsychology; context disorganization; Gamma rhythms; Gestalt theory; glutamate; grouping; memory; NMDA-receptors; PCP-psychosis; perceptual organization; schizophrenia William A. Phillips, Ph.D., is Professor of Neuropsychology at the University of Stirling, Scotland UK. He has published more than 70 papers on vision, visual memory, perceptual learning, childrens drawings, the effects of brain damage on reading and writing, and the theory of neuronal computation. He was a founder and the first Director of the Center for Cognitive and Computational Neuroscience at the University of Stirling.Steven M. Silverstein, Ph.D., is A...

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Memory impairment in schizophrenia: a study using event-related potentials in implicit and explicit tasks

Cited by 55 publications

References 52 publications

Is conceptual implicit memory impaired in schizophrenia? Evidence from lexical decision and category verification

Is conceptual implicit memory impaired in schizophrenia? Evidence from lexical decision and category verification

Stimulus- and response-locked neuronal generator patterns of auditory and visual word recognition memory in schizophrenia

Convergence of biological and psychological perspectives on cognitive coordination in schizophrenia

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