Cannabis-induced altered states of consciousness are associated with specific dynamic brain connectivity states
Yuliya Zaytseva, Jiřı́ Horáček, Jaroslav Hlinka, Iveta Fajnerová, Renáta Androvičová, Jaroslav Tintěra, Virginio Salvi, Marie Balı́ková, Tomáš Hložek, Filip Španiel, Tomáš Páleníček
Journal of Psychopharmacology June 3, 2019 DOI: 10.1177/0269881119849814 via OpenAlex
Summary
Delta-9-tetrahydrocannabinol, the active compound in cannabis, temporarily alters how brain regions communicate with each other. In 19 occasional cannabis users who underwent two resting-state fMRI scans—one shortly after smoking a cannabis cigarette and one after at least a week without cannabis—a transient connectivity state appeared only during intoxication. This state showed high connectivity within and between auditory and somato-motor cortices, along with anti-correlation with subcortical structures and the cerebellum. Subjective perceptual changes and THC plasma levels were linked to this state, suggesting a neural biomarker of cannabis intoxication.
Study at a glance
| Characteristics | Repeated-measures, within-subjects design Randomized Peer reviewed |
|---|---|
| Sample size | 19 |
| Population | Healthy occasional cannabis users (smoking cannabis ≤2 per week) |
| Intervention | cannabis cigarette |
| Duration | Four-week interval between scans; scans performed shortly after smoking (intoxicated condition) and after at least one week without cannabis (non-intoxicated condition) |
| Topics | Cannabis |
| Keywords | Precuneus Delta-9-tetrahydrocannabinol Resting State FMRI Psychology |
| Citations | 25 |
| Key finding | A transient functional connectivity state, characterized by high connectivity within and between auditory and somato-motor cortices and anti-correlation with subcortical structures and the cerebellum, was found only during cannabis intoxication and was associated with subjective perceptual changes and THC plasma levels. |
Abstract
BACKGROUND: Cannabis, and specifically one of its active compounds delta-9-tetrahydrocannabinol in recreational doses, has a variety of effects on cognitive processes. Most studies employ resting state functional magnetic resonance imaging techniques to assess the stationary effects of cannabis and to-date one report addressed the impact of delta-9-tetrahydrocannabinol on the dynamics of whole-brain functional connectivity. METHODS: Using a repeated-measures, within-subjects design, 19 healthy occasional cannabis users (smoking cannabis ⩽2 per week) underwent resting state functional magnetic resonance imaging scans. Each subject underwent two scans: in the intoxicated condition, shortly after smoking a cannabis cigarette, and in the non-intoxicated condition, with the subject being free from cannabinoids for at least one week before. All sessions were randomized and performed in a four-week interval. Data were analysed employing a standard independent component analysis approach with subsequent tracking of the functional connectivity dynamics, which allowed six connectivity clusters (states) to be individuated. RESULTS: Using standard independent component analysis in resting state functional connectivity, a group effect was found in the precuneus connectivity. With a dynamic independent component analysis approach, we identified one transient connectivity state, characterized by high connectivity within and between auditory and somato-motor cortices and anti-correlation with subcortical structures and the cerebellum that was only found during the intoxicated condition. Behavioural measures of the subjective experiences of changed perceptions and tetrahydrocannabinol plasma levels during intoxication were associated with this state. CONCLUSIONS: With the help of the dynamic connectivity approach we could elucidate neural correlates of the transitory perceptual changes induced by delta-9-tetrahydrocannabinol in cannabis users, and possibly identify a biomarker of cannabis intoxication.