One exposure to vaporized THC reduced gamma-frequency brain activity in rats across multiple brain regions, with effects persisting seven days later.
Researchers studying cannabis neuroscience and anyone interested in how vaping THC affects brain activity.
Gamma suppression persisted 7+ days after one THC vapor exposure
What the researchers found
Vaporized THC suppressed gamma power (>32-100 Hz) in the dorsal striatum, orbitofrontal cortex, and prefrontal cortex of rats, with most changes still present a week after a single exposure.
Why it matters
Gamma oscillations play a key role in cognition, and reduced gamma activity is a hallmark of schizophrenia. This study shows that even one session of vaporized THC can produce lasting changes in these brain rhythms.
The numbers in context
Gamma suppression was observed in the >32-100 Hz range across the dorsal striatum, orbitofrontal cortex, and prefrontal cortex. Effects persisted at least 7 days after a single exposure.
How the study worked
Rats were implanted with electrode arrays in three brain regions. They received vaporized THC or vehicle via a Volcano vaporizer in a crossover design with a one-week washout period, and local field potentials were recorded.
What this study cannot tell us
This was a rat study, so direct translation to humans is uncertain. The sample size was not reported in the abstract, and only a single dose was tested.
How to read the evidence
Preliminary: animal study with a single dose tested in one experiment.
When this study was published
Published in 2019.
The bigger picture
With vaping becoming the preferred delivery method for many cannabis users, understanding how vaporized THC affects brain circuits is increasingly relevant. The persistence of gamma suppression after just one exposure raises questions about cumulative effects with regular use.
Questions still open
- Do these gamma suppression effects accumulate with repeated vaporized THC exposure? Would similar patterns appear in human EEG studies? Does the effect differ with varying THC concentrations?
Common questions
What are gamma oscillations?
Why does it matter that effects lasted a week?
Read the original research
EXTENDED ATTENUATION OF CORTICOSTRIATAL POWER AND COHERENCE AFTER ACUTE EXPOSURE TO VAPOURIZED Δ9 TETRAHYDROCANNABINOL IN RATS.
The Canadian journal of addiction, 10(3), 60-66
Citation
Nelong, Tapia Foute; Jenkins, Bryan W; Perreault, Melissa L; Khokhar, Jibran Y. (2019). EXTENDED ATTENUATION OF CORTICOSTRIATAL POWER AND COHERENCE AFTER ACUTE EXPOSURE TO VAPOURIZED Δ9 TETRAHYDROCANNABINOL IN RATS.. The Canadian journal of addiction, 10(3), 60-66. https://doi.org/10.1097/cxa.0000000000000063
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