Publications by authors named "Christian Valt"

Mismatch negativity (MMN) is widely considered a candidate diagnostic biomarker for schizophrenia (SCZ). Although blunted MMN responses have been reliably observed in psychosis, the evidence for MMN deficits in other disorders, such as major depressive disorder (MDD), is mixed. This study explores whether MMN alterations in amplitude or latency are unique to SCZ or extend to non-psychotic MDD patients.

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Anomalous Mismatch Negativity (MMN) in psychosis could be a consequence of disturbed neural oscillatory activity at sensory/perceptual stages of stimulus processing. This study investigated effective connectivity within and between the auditory regions during auditory odd-ball deviance tasks. The analyses were performed on two magnetoencephalography (MEG) datasets: one on duration MMN in a cohort with various diagnoses within the psychosis spectrum and neurotypical controls, and one on duration and pitch MMN in first-episode psychosis patients and matched neurotypical controls.

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Article Synopsis
  • Microstates are brief configurations of brain activity captured by EEG, but analyzing them through MEG data presents challenges.
  • In a study with 113 MEG participants, six distinct microstates were identified related to brain activity during different resting states and an auditory task, each linked to specific brain regions.
  • A smaller group study with 21 simultaneous EEG-MEG recordings showed no direct temporal correlation between MEG and EEG microstates, suggesting they capture different aspects of brain activity, while highlighting their potential to enhance understanding of brain dynamics and dysfunction.
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Aim: The aim of this study was to investigate the characteristics of the electrophysiological brain response elicited in a passive acoustic oddball paradigm, i.e. mismatch negativity (MMN), in patients with Huntington's disease (HD) in the premanifest (pHD) and manifest (mHD) phases.

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Difficulties in various cognitive functions are common observations in people experiencing anxiety. However, limited research has investigated the effects of psychotherapy on abnormal cognitive functioning. This study assessed whether psychotherapy-related reductions of anxiety result in improvements of cognitive functioning as well.

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Background: Abnormal auditory processing of deviant stimuli, as reflected by mismatch negativity (MMN), is often reported in schizophrenia (SCZ). At present, it is still under debate whether this dysfunctional response is specific to the full-blown SCZ diagnosis or rather a marker of psychosis in general. The present study tested MMN in patients with SCZ, bipolar disorder (BD), first episode of psychosis (FEP), and in people at clinical high risk for psychosis (CHR).

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A working memory (WM) deficit is a reliable observation in people experiencing anxiety. Whether the level of anxiety is related to the severity of WM difficulties is still an open question. In the present experiment, we investigated this aspect by testing the WM performance of people with different levels of anxiety symptoms.

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The balanced processing of the internal mental world and the external world is a crucial aspect of everyday well-being. An extensive control of the internal emotional and cognitive world that often results in an internal expression of distress is a common feature of internalizing disorders. However, how depression affects the processing of the external world is still an open question.

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Introduction: Responses are optimal when they are accurate and fast. The present experiment investigated whether optimal responses evoke physiological arousal and whether performance affects the processing and evaluation of subsequent emotional material.

Methods: Participants performed a response-choice task, where feedback was a colored square reflecting performance quality or a face whose expression (happy or angry) did not indicate any aspect of performance.

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Despite the scientific consensus on the efficacy of psychotherapy for the treatment of psychological disorders, the evidence of treatment-related changes towards normalization of abnormal brain functions in patients is mixed. In the present experiment, we investigated whether treatment can affect early information processing, by testing abnormal event-related potentials (ERPs) evoked by internal and external signals in panic disorder. Sixteen patients with panic disorder and comorbid personality disorder and sixteen control participants performed a response-choice task and a passive viewing task in two testing sessions, separated by around 14 months.

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In many situations, social comparison calls for the evaluation of one´s own performance in relative terms by taking into account the performances of other people. Here, we investigated the effects of social comparison on performance monitoring with the help of ERPs. Two participants performed two identical experiments at the same time and in the same room.

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Self-absorption describes a pathological tendency towards the internal mental world (internalization) that often conflicts with the accurate monitoring of the external world. In performance monitoring, an augmented electrophysiological response evoked by internal signals in patients with anxiety or depressive disorder seems to reflect this tendency. Specifically, the error-related negativity (Ne/ERN), an index of error processing based on internal signals, is larger in patients compared to controls.

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The present study explored the relevance of internal signals for the dynamics of personal and nonpersonal feedback processing. To this end, pairs of participants performed concurrently a choice-response task and received external signals in four feedback contexts. In two contexts, feedback was informative about the personal performance (personal/private and personal/public); in the other two contexts, instructions suggested that feedback was informative about the other participant's performance (nonpersonal/other) or that it was random (nonpersonal/random).

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Performance monitoring can be based on internal or external signals. We recorded event-related potentials (ERPs) to investigate whether relating performance to external signals affects internal performance monitoring. Thirty participants performed a task in which responses were followed by faces whose expressions were partially contingent upon performance.

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According to recent interpretations of repetition priming, response codes are automatically bound to a stimulus and retrieved during successive presentations of the stimulus, hence, affecting its current processing. Despite a solid corpus of behavioural evidence in line with this interpretation, electrophysiological studies have reported contrasting results regarding the nature and the timing of response code retrieval. The present experiment aims to establish at which stage of information processing decision and action codes are retrieved in repetition priming.

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We investigated the processing of faces with different smile expressions according to a context of personal performance. Individual judgments of smile happiness were collected to assess the processing of different types of smile when these were presented as a social response in a cognitive conflict task. Two main factors were considered: (a) Expression characteristics of the smile were manipulated: that is, happy (happy-happy), neutral (neutral-happy), or sad (sad-happy) eyes were morphed in faces with smiling mouth; (b) The performance context in which the smiling face appeared as social response (after fast, average, or slow correct response).

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Response appropriateness is not exclusively limited to accuracy. Nevertheless, the processing of parameters other than accuracy for response monitoring has been mostly neglected. The present experiment explored how the cognitive system processes response speed based on internal and external signals.

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Repetition priming is a prominent example of non-declarative memory, and it increases the accuracy and speed of responses to repeatedly processed stimuli. Major long-hold memory theories posit that repetition priming results from facilitation within perceptual and conceptual networks for stimulus recognition and categorization. Stimuli can also be bound to particular responses, and it has recently been suggested that this rapid response learning, not network facilitation, provides a sound theory of priming of object recognition.

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