Inhibitory Control
Overview
Flexibility in cognitive control requires being able to selectively navigate through continuous sets of action choices. One important aspect of cognitive control is inhibitory control, which includes the ability to refrain from reacting automatically towards preset stimulus-driven responses that are inappropriate or unsafe, to prevent or withhold internal impulses (e.g., eating unhealthy food or drinking too much alcohol), or to suddenly interrupt ongoing actions that are no longer appropriate (e.g., aborting a foot movement when a pedestrian runs into the street).
Preparatory Inhibition
Transcranial magnetic stimulation (TMS) studies have shown that these behaviors engage processes that suppress excitability within the corticospinal tract. Beyond action stopping, recent research has revealed markers of motor inhibition during movement preparation—a phenomenon referred to as preparatory inhibition. Understanding the functions and neural substrates of preparatory inhibition is a central focus of our research.
Research Directions
Clinical Populations
We investigate preparatory inhibition across different patient populations:
Alcohol-dependent patients: We have demonstrated deficits in preparatory inhibition, with the strongest deficits predicting subsequent relapse—suggesting inhibition levels may serve as a biomarker for relapse risk. Current work examines relationships with brain damage (via MRI), effects of alcohol-related exposure (using virtual reality), and the potential of prebiotics supplementation on the gut-brain axis.
Pathological gamblers: Testing whether preparatory inhibition is altered in behavioral, substance-free addictions to better understand the neurobiology of impulsivity.
Parkinson’s disease: Investigating motor inhibitory control in PD patients treated with dopamine replacement therapy and/or deep brain stimulation (DBS) to elucidate the neuroanatomical structures underlying preparatory inhibition.
Novel Paradigms & Methods
We have developed new experimental tasks to dissociate different processes during action preparation. Our hypothesis is that preparatory inhibition may serve to regulate speed-accuracy tradeoffs during action choice and facilitate fine-tuning of muscle activity during motor control. Additionally, we are establishing a closed-loop TMS-EEG system to assess how sensorimotor oscillations (mu and beta rhythms) influence TMS effects on corticospinal excitability and preparatory suppression.
Long-term Goals
Our hope is that such work will elucidate mechanisms associated with diseases characterized by excessive impulsivity (addictions, OCDs, ADHD), potentially leading to novel treatment approaches to supplement classical therapies.
