Cannabis-based treatment induces polarity-reversing plasticity assessed by theta burst stimulation in humans.
Giacomo Koch, Francesco Mori, Claudia Codecà, Hajime Kusayanagi, Fabrizia Monteleone, Fabio Buttari, Stefania Fiore, Giorgio Bernardi, Diego Centonze
Brain Stimulation October 2009 DOI: 10.1016/j.brs.2009.03.001 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental study Peer reviewed |
|---|---|
| Population | Subjects with multiple sclerosis |
| Intervention | Sativex |
| Duration | Four weeks after Sativex exposure |
| Measures | motor-evoked potentials (MEPs) |
| Topics | Cannabis |
| Key findings | Sativex reversed the polarity of cTBS-induced plasticity: cTBS inhibited motor-evoked potentials before exposure but produced a persisting enhancement of MEP amplitude four weeks after. The LTP-like effect of iTBS was unaffected. The authors argue this indicates cannabis ingredients have 'metaplastic' effects and that the cannabinoid system modulates synaptic plasticity in humans. |
Abstract
In animal models, the cannabinoid system has been convincingly implicated in the regulation of long-lasting synaptic plasticity. Both long-term potentiation (LTP) and depression (LTD) phenomena can be induced in the human motor cortex by transcranial magnetic theta burst stimulation (TBS). Here, we explored the potential involvement of the cannabinoid system in TBS-induced synaptic plasticity in humans. We tested the effects of a cannabis-based preparation (Sativex) on continuous TBS (cTBS) and intermittent TBS (iTBS) protocols in subjects with multiple sclerosis. We observed a shift in the polarity of synaptic plasticity induced by cTBS. In these subjects, in fact, cTBS induced the expected inhibition of motor-evoked potentials (MEPs) before Sativex exposure, whereas it caused a persisting enhancement of MEP amplitude 4 weeks after. The LTP-like phenomenon induced by iTBS was conversely unaffected by Sativex. Our results indicate that cannabis ingredients have metaplastic effects on the motor cortex, and strongly suggest that the cannabinoid system is involved in the modulation of synaptic plasticity not only in rodents but also in humans.
Comparable studies
Other experimental studies on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Smoked Cannabis' Psychomotor and Neurocognitive Effects in Occasional and Frequent Smokers Occasional (<2x/week) and frequent (≥4x/week) cannabis smokers | 2015 | Controlled within-subjects study | n = 25 |
| Dissociable effects of cannabis with and without cannabidiol on the human brain’s resting-state functional connectivity Healthy volunteers experienced with cannabis but not regular users | 2019 | Within-subjects experimental design | n = 17 |
| Which biological and self-report measures of cannabis use predict cannabis dependency and acute psychotic-like effects? Young cannabis users | 2018 | Observational study (naturalistic, within-subject counterbalanced design) | n = 410 |
| Cannabis Essential Oil: A Preliminary Study for the Evaluation of the Brain Effects Healthy volunteers | 2018 | Experimental study | n = 5 |
| Coming off cannabis: a cognitive and magnetic resonance imaging study in patients with multiple sclerosis Patients with multiple sclerosis who began using cannabis after disease onset, used it... | 2019 | Quasi-experimental study with odd-even allocation | n = 40 |