RESEARCH
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.
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.
Combining the best features of the existing methods, 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 high subthreshold electric fields, frequency specificity and the spatial specificity. The only percept associated with kTMP is an auditory tone that can be masked, making kTMP a comfortable method of stimulation in a clinical setting and amenable for double-blind experimentation.
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.
Weill Neurohub Project: Advancing Motor Recovery in Chronic Stroke Patients with kTMP
Approximately 800,000 Americans suffera stroke each year. The most common deficit after stroke is hemiparesis: approximately 80% of patients experience upper limb impairment in the acute phase and 40% will have to live with long term impairment (Hatem et al., 2016).
The goal of this pilot project is to use the kTMP non-invasive approach to test its immediate effects on chronic stroke motor recovery.
This project is a collaboration headed by Profs. Richard Ivry (UCB) and Karunesh Ganguly (UCSF). Prof. Ivry is an expert in motor control and learning, employing non-invasive brain stimulation to study these processes in neurologically healthy and neurologically impaired individuals. Prof. Ganguly (USCF) is an expert in motor learning and stroke recovery.
While we focus here on stroke, the project provides a broader roadmap for kTMP as a non-invasive treatment for a wide range of neurological disorders.
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Click here for our published kTMP paper on eLife.