Exploring the Parameter Space of High Frequency Magnetic Perturbation in Manipulating Neural Excitability and Plasticity.

Project Summary/Abstract The kTMP electric field, which may be amplitude-modulated, couples with brain neurons to modify neuronal dynamics. To simultaneously record EEG signals while administering kTMP, the head coil must be brought in close proximity to the EEG electrodes. As a result, the EEG recordings could be contaminated with a high- amplitude 2-5 kHz component with amplitude modulation sidebands. Ideally, the kTMP signals can be removed from the EEG signal by digital low-pass filtering. We have encountered a non-ideal behavior in our combined kTMP and EEG system: Discrete peaks in the 0-100 Hz range have arisen in our EEG recordings that obfuscate the observation of changes to EEG signals in that same range. Tests to-date indicate that the EEG amplifier is likely the source of the artifacts. We are seeking TABA funds to remove these artifacts at the hardware level by building an analog low-pass filter bank for the EEG amplifier and a high-pass filter for the kTMP high-current amplifier.