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Your search keyword '"Alekseichuk, Ivan"' showing total 45 results
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45 results on '"Alekseichuk, Ivan"'

28. Medial prefrontal cortex involvement in aesthetic appreciation of paintings: a tDCS study

Author

Ministero dell'Istruzione, dell'Università e della Ricerca, Fondazione Mondino, Cattaneo, Zaira, Ferrari, Chiara, Schiavi, Susanna, Alekseichuk, Ivan, Antal, Andrea, Nadal, Marcos, Ministero dell'Istruzione, dell'Università e della Ricerca, Fondazione Mondino, Cattaneo, Zaira, Ferrari, Chiara, Schiavi, Susanna, Alekseichuk, Ivan, Antal, Andrea, and Nadal, Marcos

Abstract

Among the brain regions involved in the aesthetic evaluation of paintings, the prefrontal cortex seems to play a pivotal role. In particular, consistent neuroimaging evidence indicates that activity in the dorsolateral prefrontal cortex (mainly in the left hemisphere) and in medial and orbital sectors of the prefrontal cortex is linked to viewing aesthetically pleasing images. In this study, we focused on the contribution of the medial prefrontal cortex (mPFC) in mediating aesthetic decisions about paintings. We found that enhancing excitability in this region via anodal tDCS led participants to judge paintings as more beautiful. Although significant, the effects were moderate, possibly due to the neutral affective value of the artworks we used, suggesting that activity in mPFC may be critically dependent on the affective impact of the paintings.

Published
2020

44. Real-time TMS-EEG for brain state-controlled research and precision treatment: a narrative review and guide.

Author

Wischnewski M, Shirinpour S, Alekseichuk I, Lapid MI, Nahas Z, Lim KO, Croarkin PE, and Opitz A

Abstract

Transcranial magnetic stimulation (TMS) modulates neuronal activity, but the efficacy of an open-loop approach is limited due to the brain state's dynamic nature. Real-time integration with electroencephalography (EEG) increases experimental reliability and offers personalized neuromodulation therapy by using immediate brain states as biomarkers. Here, we review brain state-controlled TMS-EEG studies since the first publication several years ago. A summary of experiments on the sensorimotor mu rhythm (8-13 Hz) shows increased cortical excitability due to TMS pulse at the trough and decreased excitability at the peak of the oscillation. Pre-TMS pulse mu power also affects excitability. Further, there is emerging evidence that the oscillation phase in theta and beta frequency bands modulates neural excitability. Here, we provide a guide for real-time TMS-EEG application and discuss experimental and technical considerations. We consider the effects of hardware choice, signal quality, spatial and temporal filtering, and neural characteristics of the targeted brain oscillation. Finally, we speculate on how closed-loop TMS-EEG potentially could improve the treatment of neurological and mental disorders such as depression, Alzheimer's, Parkinson's, schizophrenia, and stroke. &#xD., (© 2024 The Author(s). Published by IOP Publishing Ltd.)

Published
2024
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45. Experimental validation of computational models for the prediction of phase distribution during multi-channel transcranial alternating current stimulation.

Author

Lee S, Shirinpour S, Alekseichuk I, Perera N, Linn G, Schroeder CE, Falchier AY, and Opitz A

Abstract

Transcranial alternating current stimulation (tACS) is a widely used noninvasive brain stimulation (NIBS) technique to affect neural activity. Neural oscillations exhibit phase-dependent associations with cognitive functions, and tools to manipulate local oscillatory phases can affect communication across remote brain regions. A recent study demonstrated that multi-channel tACS can generate electric fields with a phase gradient or traveling waves in the brain. Computational simulations using phasor algebra can predict the phase distribution inside the brain and aid in informing parameters in tACS experiments. However, experimental validation of computational models for multi-phase tACS is still lacking. Here, we develop such a framework for phasor simulation and evaluate its accuracy using in vivo recordings in nonhuman primates. We extract the phase and amplitude of electric fields from intracranial recordings in two monkeys during multi-channel tACS and compare them to those calculated by phasor analysis using finite element models. Our findings demonstrate that simulated phases correspond well to measured phases (r = 0.9). Further, we systematically evaluated the impact of accurate electrode placement on modeling and data agreement. Finally, our framework can predict the amplitude distribution in measurements given calibrated tissues’ conductivity. Our validated general framework for simulating multi-phase, multi-electrode tACS provides a streamlined tool for principled planning of multi-channel tACS experiments.

Published
2023
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