Using Brain State-dependent Transcranial Magnetic Stimulation for Investigating Causal Role of Cortical Oscillations in Functional States
Andraz Matkovi, Jure Bon, Zvezdan PirtoÅ¡ek
Journal of Electronic Systems, Vol. 9, No. 1, 2019.
DOI: 
Link: http://www.dline.info/jes/fulltext/v9n1/jesv9n1_3.pdf
Abstract:
Non-invasive brain stimulation is being used for manipulation of cortical oscillations in research and clinical context for development of possible therapeutic applications in brain disorders. Effects of brain stimulation show strong inter- and intra-individual variation. In general there are several sources of this variability, e.g. neuroanatomical and neurochemical factors. This article describes our work in the scope of EkoSMART consortium on development of peripheral sensing techniques. Here we focus on the rapidly varying neurophysiological factors â€“ cortical oscillations. Current state of
cortical oscillations can be continually recorded with peripheral sensors like EEG scalp electrodes and used online for
continuous monitoring and adjustments of brain stimulation parameters. By adjusting the timing, intensity and frequency of
transcranial stimulation to specific brain states it is possible to reduce variation in the treatment effects. However, since brain
state-dependent stimulation (BSDS) requires online monitoring and analysis of neurophysiological data, it is technically
demanding. BSDS has been made possible by recent technological advances and advances in analytical procedures. While
EEG data has been traditionally analyzed in time- or frequency-domain only, time frequency analysis is being increasingly
used and it offers better insight into neurophysiology of oscillations. BSDS is useful in the field of clinical neuroscience,
where it can be used to personalize stimulation parameters, e.g. adjust deep brain stimulation depending on the severity in symptoms in Parkinsonâ€™s disease. Because it enables manipulation of cortical oscillations when a specific brain state is detected, it allows stronger causal inferences about their role in behavior and brain states. Therefore, BSDS can be also used as a tool for verification or falsification of hypotheses in cognitive neuroscience.