International journal of psychophysiology : official journal of the International Organization of Psychophysiology
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Int J Psychophysiol · Jun 2021
ReviewMaking ERP research more transparent: Guidelines for preregistration.
A combination of confirmation bias, hindsight bias, and pressure to publish may prompt the (unconscious) exploration of various methodological options and reporting only the ones that lead to a (statistically) significant outcome. This undisclosed analytic flexibility is particularly relevant in EEG research, where a myriad of preprocessing and analysis pipelines can be used to extract information from complex multidimensional data. One solution to limit confirmation and hindsight bias by disclosing analytic choices is preregistration: researchers write a time-stamped, publicly accessible research plan with hypotheses, data collection plan, and the intended preprocessing and statistical analyses before the start of a research project. In this manuscript, we present an overview of the problems associated with undisclosed analytic flexibility, discuss why and how EEG researchers would benefit from adopting preregistration, provide guidelines and examples on how to preregister data preprocessing and analysis steps in typical ERP studies, and conclude by discussing possibilities and limitations of this open science practice.
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Int J Psychophysiol · Jun 2020
ReviewModulation of gamma oscillations as a possible therapeutic tool for neuropsychiatric diseases: A review and perspective.
Gamma oscillations (30-80 Hz) are well-known for their role in cortical signal transmission and cognitive brain functions. Aberrant gamma activity has been observed in various neuropsychiatric disorders, but the clinical potential of restoring gamma oscillations via noninvasive brain stimulation has been widely neglected. ⋯ Then, we suggest transcranial alternating current stimulation (tACS) as an alternative brain stimulation technique and review the recent literature on the effects of gamma tACS in healthy volunteers and neuropsychiatric diseases to document the efficacy of gamma tACS in improving cognitive functions. We discuss several advantages of tACS compared to rhythmic sensory stimulation for the entrainment of gamma oscillations in the human brain and emphasize the need for more clinical studies applying tACS to drive gamma oscillations and, in turn, to improve cognitive functioning not only in AD but also in patients suffering from other neuropsychiatric disorders.
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Int J Psychophysiol · Nov 2019
ReviewThe interhemispheric miscommunication theory of auditory verbal hallucinations in schizophrenia.
Auditory verbal hallucinations (AVH) are hallmark symptoms of schizophrenia and have been linked to abnormal activation, connectivity and integration within the auditory, language, and memory brain networks. The interhemispheric miscommunication theory of AVH is based on a steadily growing number of studies using a variety of modalities (EEG, fMRI, DTI) reporting that both altered integrity of the interhemispheric auditory pathways and disturbed functional gamma-band synchrony between right and left auditory cortices significantly contribute to abnormal auditory processing and the emergence of AVH. Moreover, initial studies using pharmacological EEG and 1H MR spectroscopy provided first insights into the underlying neurochemistry of AVH. ⋯ In support, a potential NMDAR hypofunction is proposed to be compensated by increased levels of glutamate in prefrontal and auditory brain areas. In this mini-review paper, we used the levels of explanation approach and present how interhemispheric brain connectivity (brain-imaging level) corresponds to auditory perception (cognitive level), and eventually how these parameters are related to changes in neurotransmission (cellular level) and to the occurrence of AVH (clinical level). To the best of our knowledge, this is the first overview that overcomes traditional boundaries and presents converging evidence from different levels of knowledge that validate and support each other, and particularly point toward the role of an interhemispheric miscommunication in AVH.
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Int J Psychophysiol · Oct 2018
Subconcussive head impacts in sport: A systematic review of the evidence.
To identify and evaluate the evidence that examines subconcussive impacts in sport-specific settings, and address two objectives: a) to determine how 'subconcussion' is characterized in the current literature, and b) to identify directions for future research. ⋯ Evidence reviewed predominantly from studies of male athletes in contact and collision sports identifies that repetitive hits to the head are associated with microstructural and functional changes in the brain. Whether these changes represent injury is unclear. We determined the term 'subconcussion' to be inconsistently used, poorly defined, and misleading. Future research is needed to characterize the phenomenon in question.
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Int J Psychophysiol · Aug 2013
ReviewThe microstructure of sleep in primary insomnia: an overview and extension.
The present review was undertaken to summarize studies elucidating sleep microstructural differences in chronic insomnia. The etiology of insomnia is still unknown, whereas the hyperarousal concept has gained much attention with respect to pathophysiology. According to this model, insomnia is characterized by significant hyperarousal on an autonomous and central nervous level. ⋯ These methods include the spectral analysis of the sleep EEG, micro-arousal and CAP (cyclic alternating pattern) analysis as well as the assessment of event-related potentials (ERPs) during night-sleep. The application of these methods shows stronger correlations with the subjective experience of disturbed sleep than standard sleep EEG scoring. An overview of the relevant empirical evidence is presented, previous investigations are extended and a theoretical synthesis within the framework of the hyperarousal concept of insomnia is attempted.