THC Disrupted the Brain's Ability to Filter Sensory Information in Both Humans and Rats | Research

The takeaway

THC disrupted sensory gating and theta-band brain oscillations in both human volunteers and rats through CB1 receptor activation, with CBD failing to block these effects when co-administered.

Neuroscience researchers, psychiatrists, psychopharmacologists.

THC-induced reduction in theta oscillations correlated with impaired sensory gating (r = -0.629), and CBD co-administration did not block these effects.

What the researchers found

Both THC and THC+CBD disrupted P50 sensory gating in humans and reduced evoked theta and gamma oscillations. In rats, the CB1R agonist CP-55940 disrupted gating in the hippocampus and entorhinal cortex, effects reversed by the CB1R antagonist AM-251. Theta oscillation reductions correlated with gating impairment in humans.

Why it matters

Sensory gating - the brain's ability to filter out redundant stimuli - is impaired in schizophrenia. This study shows THC disrupts the same process through CB1 receptors, providing a mechanistic link between cannabis use and psychosis-like symptoms.

The numbers in context

15 human subjects, 4 conditions. THC disrupted P50 gating ratio significantly. THC-induced theta power reduction correlated with gating impairment (r = -0.629, p < 0.012). CBD did not block THC's effects.

How the study worked

Translational study: 15 human subjects received IV THC, CBD, THC+CBD, or placebo in a crossover design with EEG recording. Separately, 6 rats received a CB1R agonist, CB1R agonist+antagonist, or vehicle with local field potential recording from hippocampus and entorhinal cortex.

What this study cannot tell us

Small sample sizes (15 humans, 6 rats). Acute dosing only. The rat CB1R agonist (CP-55940) differs pharmacologically from THC. CBD may need different dosing to show protective effects.

How to read the evidence

Moderate - strong translational design with convergent human/animal findings, but small sample sizes.

When this study was published

Published in 2018.

The bigger picture

The convergent human and animal findings strengthen the evidence that CB1 receptor activation disrupts fundamental information processing in ways relevant to psychosis. The failure of CBD to protect against these effects is also notable.

Questions still open

Would chronic cannabis use produce lasting sensory gating deficits? Could higher CBD doses counteract THC's gating effects? Do individuals with pre-existing gating deficits experience greater THC effects?

Common questions

How does THC affect how the brain processes information?

THC disrupted "sensory gating" - the brain's ability to filter out repeated stimuli - by altering theta-band oscillations through CB1 receptor activation. This was confirmed in both human EEG and rat brain recordings.

Does CBD protect against THC's brain effects?

In this study, CBD did not prevent THC's disruption of sensory gating when the two were co-administered, suggesting CBD may not protect against all of THC's cognitive effects.

Read the original research

Cannabinoid receptor-mediated disruption of sensory gating and neural oscillations: A translational study in rats and humans.

Neuropharmacology, 135, 412-423

View on PubMed ↗Publisher’s paper ↗

Citation

Skosnik, Patrick D; Hajós, Mihály; Cortes-Briones, Jose A; Edwards, Chad R; Pittman, Brian P; Hoffmann, William E; Sewell, Andrew R; D'Souza, Deepak C; Ranganathan, Mohini. (2018). Cannabinoid receptor-mediated disruption of sensory gating and neural oscillations: A translational study in rats and humans.. Neuropharmacology, 135, 412-423. https://doi.org/10.1016/j.neuropharm.2018.03.036