EEG-driven closed-loop xTMS for the modulation of neural oscillations underpinning motor learning and execution

Lead supervisor: Professor Andrew Sharott

Co-supervisors: Professor Chalotte Stagg, Professor Timothy Denison 

Commercial partner: Magstim

Brain stimulation approaches that can precisely modulate oscillatory activity have the potential to provide a powerful method of manipulating healthy and disease-related neural processing. As oscillations at different frequencies provide temporal reference frames for the maintenance and processing of information at specific timescales, modulating their strength provides a powerful and targeted approach to alter different types of computation. Phase-targeted stimulation provides a particularly powerful approach, as it can amplify or suppress ongoing oscillations depending on the precise phase being targeted. This can in turn modulate the motor and cognitive functions associated with those oscillations. For example, we have shown phase-targeted modulation of theta oscillations in memory circuits can powerfully modulate these activities, altering cognitive performance (Clarke-Williams et al., 2024; Gava et al., 2024; McHugh et al., 2024; Grennan et al., 2025). Conversely, suppressing oscillations that are associated with disease symptoms (e.g. beta oscillations and tremor in Parkinson’s disease) could provide novel therapeutic approaches.

Non-invasive electrical brain stimulation, such as transcranical magnetic stimulation (TMS), often produce small effect sizes, because to the loss of energy/focality as the stimulation pass through the skull. Phase-targeted stimulation has huge potential to enhance the effect size of non-invasive stimulation methods by harnessing ongoing neural dynamics. If stimuli are repeatedly delivered to the same phase of an ongoing oscillatory process, which provides a temporal window for a specific brain process, the effects a likely to be more powerful that if delivering the same stimulus without reference to ongoing activity.  However, conventional TMS hardware is ill equipped to deliver pulses in response to ongoing inputs from closed-loop systems.  We have recently show that xTMS, a novel TMS system developed in collaboration with Magstim, can deliver phase-targeted stimulation at 6Hz driven by tremor activity in the accelerometer.  Using EEG-oscillations as the input to the closed-loop would greatly expand the scope of this approach to modulate a range of neural oscillations, including higher frequencies, in health and disease, but requires a novel technical approach whereby the EEG signal can continuously provide input to the closed-loop system in the presence of stimulation artifacts.

In this project, we will combine our novel phase tracking algorithms with the Magstim EEG-recording methods and xTMS stimulation to modulate motor cortical oscillations, using a well-established experimental set up to measure movement parameters. Motor cortical oscillations provide a particularly useful starting point, as the effects of modulation can be measured using simple motor tasks.  Specifically, we will test whether phase targeted stimulation of mu and beta oscillations in the EEG will modulate motor learning and execution. We will achieve this by applying phase-targeted stimulation at specific task points (e.g. post-movement beta rebound) in a well-characterised motor task using a Kinarm robot. The student on this project will drive the technical implementation/validation of EEG-driven phase-locked TMS by integrating methods from the academic and industrial teams and perform these experiments. Achieving these goals would deliver novel methods of brain stimulation and test the causal role of these oscillations specific aspects of motor control.

Apply using course: DPhil in Clinical Neuroscience