Mapping event-related brain potential microstates to sentence endings

Brandeis, Daniel; Lehmann, Dietrich; Michel, Christoph M.; Mingrone, Walter

doi:10.1007/bf01199778

Cited by 104 publications

(78 citation statements)

References 34 publications

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“…To statistically assess the validity of the microstate results, we applied a fitting procedure based on the calculation of the spatial correlation between single-subject ERPs and template maps (47,49). For each subject and condition, the amount of time characterized by each template was obtained in a specific time window of interest.…”

Section: Discussionmentioning

confidence: 99%

Spatiotemporal dynamics in understanding hand—object interactions

Avanzini

Fabbri-Destro

Campi

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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It is generally accepted that visual perception results from the activation of a feed-forward hierarchy of areas, leading to increasingly complex representations. Here we present evidence for a fundamental role of backward projections to the occipitotemporal region for understanding conceptual object properties. The evidence is based on two studies. In the first study, using highdensity EEG, we showed that during the observation of how objects are used there is an early activation of occipital and temporal areas, subsequently reaching the pole of the temporal lobe, and a late reactivation of the visual areas. In the second study, using transcranial magnetic stimulation over the occipital lobe, we showed a clear impairment in the accuracy of recognition of how objects are used during both early activation and, most importantly, late occipital reactivation. These findings represent strong neurophysiological evidence that a top-down mechanism is fundamental for understanding conceptual object properties, and suggest that a similar mechanism might be also present for other higher-order cognitive functions.object use understanding | top-down effect | conceptual knowledge C lassic studies on the neural basis of visual perception showed that neurons located in progressively higher cortical visual areas in the macaque monkey show increasingly complex properties (1-5). On the basis of these findings, it was proposed that neural substrate crucial for visual perception is represented by the higher-order visual areas of the inferior temporal lobe (6-8). Functional MRI (fMRI) data obtained in humans confirmed these findings (9, 10). These data also suggested that the temporal lobe poles are an even higher integration center, where conceptual object properties (e.g., how an object is commonly used) are represented (11-13).Visual information processing has been classically considered to be a feed-forward processing, with perception occurring when the areas at the top of the network become active (6, 14-16). On the other hand, rich anatomical evidence shows that there are massive feedback connections going from higher-order areas back to lower-order areas of the visual ventral stream (17-21). Physiological data also provide evidence for cross-talk between visual areas located at different hierarchical level. In fact transcranial magnetic stimulation (TMS) studies (22-26) reported that single-pulse TMS applied over primary visual areas produces significant perceptual impairment in two distinct time windows: an early one and a late one, relative to the presentation of a visual stimulus. The perception impairment caused by stimulation during the second (late) time window was interpreted as a consequence of an interference with a top-down reactivation of V1 (27,28). A TMS study by Pascual-Leone and Walsh (29) demonstrated that stimulation of area MT/V5 applied 30 ms before the stimulation of V1 affects the activity of this latter region, making participants perceive still rather than moving phosphenes. An analogous cross-talking ef...

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Section: Discussionmentioning

confidence: 99%

Spatiotemporal dynamics in understanding hand—object interactions

Avanzini

Fabbri-Destro

Campi

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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“…This clustering procedure identifies the topographies (ie maps) dominating the group-averaged AEPs across populations/ conditions. The pattern observed at the group-average level was then statistically assessed at the individual participant level using a fitting procedure based on spatial correlation (Brandeis et al, 1995; see also Murray et al, 2006, for a recent publication of formulae), yielding a measure of map presence. These values are then submitted to ANOVA, revealing whether and when different maps explain CGI and PANSS scales: S, severity; I, improvement; P, positive; N, negative; G, general psychopathology; T, total score.…”

Section: Eeg Recordings and Analysesmentioning

confidence: 99%

Glutathione Precursor, N-Acetyl-Cysteine, Improves Mismatch Negativity in Schizophrenia Patients

Lavoie

Murray

Deppen

et al. 2007

Neuropsychopharmacol

327

227

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In schizophrenia patients, glutathione dysregulation at the gene, protein and functional levels, leads to N-methyl-D-aspartate (NMDA) receptor hypofunction. These patients also exhibit deficits in auditory sensory processing that manifests as impaired mismatch negativity (MMN), which is an auditory evoked potential (AEP) component related to NMDA receptor function. N-acetyl-cysteine (NAC), a glutathione precursor, was administered to patients to determine whether increased levels of brain glutathione would improve MMN and by extension NMDA function. A randomized, double-blind, cross-over protocol was conducted, entailing the administration of NAC (2g/day) for 60 days and then placebo for another 60 days (or vice versa). 128-channel AEPs were recorded during a frequency oddball discrimination task at protocol onset, at the point of cross-over, and at the end of the study. At the onset of the protocol, the MMN of patients was significantly impaired compared to sex-and age-matched healthy controls (p ¼ 0.003), without any evidence of concomitant P300 component deficits. Treatment with NAC significantly improved MMN generation compared with placebo (p ¼ 0.025) without any measurable effects on the P300 component. MMN improvement was observed in the absence of robust changes in assessments of clinical severity, though the latter was observed in a larger and more prolonged clinical study. This pattern suggests that MMN enhancement may precede changes to indices of clinical severity, highlighting the possible utility AEPs as a biomarker of treatment efficacy. The improvement of this functional marker may indicate an important pathway towards new therapeutic strategies that target glutathione dysregulation in schizophrenia.

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“…The pattern of maps observed in the group-averaged data were statistically tested by comparing each of these maps with the moment-by-moment scalp topography of individual subjects' VEPs from each condition. Each time point of each VEP from each subject was labeled according to the map with which it best correlated spatially [spatial correlation has been defined by Brandeis et al (1995)]. This method determines whether a given experimental condition is more often described by one map versus another and, therefore, whether different generator configurations better account for particular experimental conditions.…”

Section: Eeg Acquisition and Analysesmentioning

confidence: 99%

Boundary Completion Is Automatic and Dissociable from Shape Discrimination

et al. 2006

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Normal visual perception readily overcomes suboptimal or degraded viewing conditions through perceptual filling-in processes, enhancing object recognition and discrimination abilities. This study used visual evoked potential (VEP) recordings in conjunction with electrical neuroimaging analyses to determine the spatiotemporal brain dynamics of boundary completion and shape discrimination processes in healthy humans performing the so-called "thin/fat" discrimination task (Ringach and Shapley, 1996) with stimuli producing illusory contours. First, results suggest that boundary completion processes occur independent of subjects' accuracy on the discrimination task. Modulation of the VEP to the presence versus absence of illusory contours [the IC effect (Murray et al., 2002)] was indistinguishable in terms of response magnitude and scalp topography over the 124 -186 ms poststimulus period, regardless of whether task performance was correct. This suggests that failure on this discrimination task is not primarily a consequence of failed boundary completion. Second, the electrophysiological correlates of thin/fat shape discrimination processes are temporally dissociable from those of boundary completion, occurring during a substantially later phase of processing (ϳ330 -406 ms). The earlier IC effect was unaffected by whether the perceived contour produced a thin or fat shape. In contrast, later time periods of the VEP modulated according to perceived shape only in the case of stimuli producing illusory contours, but not for control stimuli for which performance was at near-chance levels. Collectively, these data provide further support for a multistage model of object processing under degraded viewing conditions.

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Mapping event-related brain potential microstates to sentence endings

Cited by 104 publications

References 34 publications

Spatiotemporal dynamics in understanding hand—object interactions

Spatiotemporal dynamics in understanding hand—object interactions

Glutathione Precursor, N-Acetyl-Cysteine, Improves Mismatch Negativity in Schizophrenia Patients

Boundary Completion Is Automatic and Dissociable from Shape Discrimination

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