Cortical changes detected with MEG in Tourette syndrome following [formula omitted]9-tetrahydrocannabinol challenge test

Abstract

Cannabinoids have surged as potential therapeutic drugs in neurological disorders, especially in movement disorders. We investigated the responsivity to Δ9-tetrahydrocannabinol (THC) of a 43-years-old woman affected by Tourette Syndrome (TS). To reveal cortical changes induced by THC and correlating with the decrease of tics, we acquired magnetoencephalography (MEG) during a Go/No Go (GNG) task, before and after THC administration. To characterize the modulation of cortical activity, the event-related desynchronization/synchronization (ERD/ERS) analysis was applied. To localize the source related to frequency of interest, the Dynamical Imaging of Coherent Sources method was applied4 contrasting two periods of interest (‘Go’ and ‘no Go’ conditions). In ‘Go’ condition, no differences between pre and post THC was noticed. In ‘No go’ condition, after the THC intake, a decrease in beta band activity of cortical motor areas was followed by a noteworthy increase of beta activity within 1s after the presentation of the cue, correlated with an amelioration of tics control. Our findings showed that the increased tics control after THC intake was associated to a restoration of the ERD/ERS (namely beta synchronization) involving precentral and postcentral gyri, thus highlighting that THC-induced modifications impacted on cortical motor circuitries.