Browsing by Author "Rytioja, Maria"

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  • The effects of transcranial direct current stimulation on oscillatory brain activity
    (2016-10-31) Rytioja, Maria
     Sähkötekniikan korkeakoulu | Master's thesis
    Transcranial direct current stimulation (tDCS) is a potential new brain stimulation method for depression treatment. The aim of this thesis was to investigate whether the effect of tDCS treatment in depression could be monitored with electroencephalography (EEG). This thesis comprises a review including literature of EEG-based depression biomarkers and tDCS-induced effects on healthy controls and a feasibility study of tDCS-induced effects on oscillatory brain activity. In order to treat each individual patient with the most efficient methods, there has been a great interest to study treatment-predictive biomarkers for depression. However, such biomarkers for tDCS have not yet been investigated. Although there is evidence of tDCS-induced effects on oscillatory brain activity and cognitive performance in healthy controls. In this feasibility study, we investigated whether the effects of tDCS can be measured in EEG after stimulation. Ten healthy volunteers, aged from 20 to 40 years, were studied by measuring their brain activity before and after a tDCS session with EEG. The tDCS protocol was similar to the one used in depression therapy. All subjects attended two sessions and received both active and sham stimulation on separate days in a random order. During the recording and stimulation subjects were executing sudokus to maintain constant cognitive load. Changes in brain activity were analysed in delta (2–4 Hz), theta (4–8 Hz), alpha (8–13 Hz) and beta (13–30 Hz) frequency ranges. The results show that tDCS, compared to sham stimulation, prevents the decrease of beta-band power in the frontopolar area and theta-band power in the right parietal cortex during the 30-min task performance. This study indicates that frontopolar EEG electrodes can be used to verify the tDCS-induced effects right after the stimulation. Studies on patients are needed to verify potential tDCS effects on depression.
  • Hiiren sauvasolun valovastekinetiikan lämpötilariippuvuuden määrittäminen
    (2013-05-30) Rytioja, Maria
     Sähkötekniikan korkeakoulu | Bachelor's thesis