Non-invasive brain stimulation (NIBS) refers to a set of methods used to safely modulate human brain function by transiently altering the state of targeted neurons. There has been a surge of interest in NIBS methods over the past 30 years. Research scientists use NIBS to test causal hypotheses about brain-behavior relationships; clinicians have recognized the potential of NIBS as providing a new intervention in the treatment of neurological and psychiatric disorders.
The two most common NIBS methods are transcranial electrical stimulation (tES) and transcranial magnetic stimulation (TMS). With tES, a continuous modulatory signal can be induced, allowing the experimenter to increase or decrease the state of excitability of the targeted neural region. Moreover, the frequency of this signal can be varied, enhancing or attenuating endogenous brain rhythms. However, due to safety concerns tES can only apply very weak cortical electric fields. Despite the promise of tES, there are substantial concerns about the reliability and robustness of its physiological and behavioral effects. These issues are likely due to the relatively weak cortical electric fields of tES.
In contrast to tES the TMS method, which can safely deliver much stronger cortical electric fields, can induce robust changes in neuronal state and behavior. Furthermore TMS has superior spatial specificity compared to tES. However, conventional TMS lacks frequency specificity in that its associated electric fields can only be delivered as very brief pulses.
To address these concerns, we have developed kTMP (kilohertz Transcranial Magnetic Perturbation), a method which will open a new experimental space of NIBS methods. This space is characterized by strong electric fields, frequency specificity and the spatial specificity of TMS. We believe exploration of this new NIBS subspace will yield new, reliable and effective effects on brain function that will lead to effective treatment options for neurologic and psychiatric disease.