Tonik kas aktivitesinin EEG signaline karışımı

Electroencephalography (EEG) is an important tool for the measurement and monitoring the brain's electrical activity. EEG signal is recorded with electrodes placed on the scalp. However, the electrical activity of muscles can interfere with the electroencephalogram (EEG) signal considering the anatomical locations of facial or masticatory muscles surrounding the skull. Temporalis muscle (m. temporalis) holds the mandible in physiological rest position and it covers a large area under the EEG electrodes. In this study, we evaluated the possible interference of the resting activity of the temporalis muscle on the EEG under conventional EEG recording conditions. In 9 healthy adults EEG activity from 19 scalp locations and single motor unit (SMU) activity from anterior temporalis muscle were recorded in three relaxed conditions; eyes open, eyes closed, jaw dropped. For the analysis of the data, EEG signal was spike triggered averaged (STA) for different EEG electrode locations. Action potentials of SMUs were used as triggers for the STA procedure. Resting temporalis SMU activity generated prominent Macro-EMEG (electro-myo-encephalogram) potentials with different amplitudes, reaching maxima in the proximity of the recorded SMU. Interference was also notable at the scalp sites that are relatively far from the recorded SMU and even at the contralateral locations. The head and neck are surrounded by muscles with a great number of SMUs. Therefore, EEG is highly susceptible to muscle activity artifacts even under rest conditions. This study emphasizes the need for efficient artifact evaluation methods which can handle muscle interferences.