Synaptic Plasticity in Primary Motor Cortex and Brainstem in Gilles de la Tourette Syndrome

Grant Type
Grant Year
Institution Location
Institution Organization Name
Sapienza University of Rome, Rome, Italy
Investigators Name
Berardelli, Alfredo, MD

Plasticity refers to the nervous system’s ability to undergo activity-dependent changes that can strengthen or weaken synaptic transmission. In experimental studies, one possible approach to explore synaptic plasticity is to measure changes in post-synaptic responses after repetitive stimulation of pre-synaptic terminals. In human studies, plasticity can be tested non-invasively by delivering repetitive transcranial magnetic stimulation (rTMS) over primary motor cortex (M1) and then measuring changes in motor evoked potential (MEP) size after rTMS. Synaptic plasticity can also be explored in the human brainstem by delivering electric high-frequency stimulation (HFS) to the supraorbital nerve and measuring persistent changes in the blink reflex late response (R2) area. No studies have to our knowledge investigated synaptic plasticity at M1 and brainstem level in patients with Tourette syndrome (TS) and Obsessive-Compulsive Disorder (OCD). Having more information on possible changes in M1 and brainstem synaptic plasticity is crucial in clarifying the pathophysiologic mechanisms underlying TS and OCD and it will be instrumental for possible novel neurostimulating approaches. The aim of the study is to investigate M1 and brainstem synaptic plasticity in adult cohorts of people with TS, TS + OCD, and OCD. In addition, given that in healthy humans the degree of response to different plasticity-inducing protocols is also dependent on genetic factors including polymorphism of Brain Derived Neurotrophic Factor (BDNF), this project will also test BDNF polymorphism in patients with TS, TS + OCD and OCD. Finally, we will investigate the possible relationship between clinical features (severity of tics and obsessions/compulsions), neurophysiologic (response to different plasticity-inducing protocols) and genetic features (BDNF-Val66Met polymorphism) in people with TS, TS + OCD and OCD. Alfredo Berrardelli, M.D., Antonio Suppa, M.D., Daniele Belvisi, M.D., Isabella Berardelli, M.D. Sapienza University of Rome, Rome, Italy Award: $60,000 Commentary: Plasticity refers to the nervous system’s ability to undergo functional changes following certain activities, and is thought to be crucial in high level brain functions including learning, memory and motor performance. One way to explore plasticity in humans is to stimulate the brain and then to measure changes in activity. This study will investigate plasticity in specific areas of the brain in people with Tourette syndrome (TS) and Obsessive-Compulsive Disorder (OCD). This information will help us understand the brain changes responsible for causing TS and OCD. The study will also test possible relationships between brain plasticity and genetic aspects of TS and OCD. Tourette Association of America Inc. – Research Grant Award 2011-2012