Boosting brain excitability by transcranial high frequency stimulation in the ripple range

Introduction: High frequency neuronal oscillations in the range of 80–250Hz, termed the 'ripple range', play a key role both in normal and abnormal brain functions such as epilepsy. The concept described here is an attempt to modulate neuronal excitability by high frequency transcranial alternating current stimulation (tACS) in the ripple range, in a frequency-dependent fashion. Here, for the first time we have tested the effects of 80, 140 and 250Hz oscillations on motor evoked potential (MEP) amplitude Methods: Altogether 12 subjects participated in the experiments. They received on separate days AC- (80Hz, 14…