THC impairs movement by shifting the brain's excitation-inhibition balance in the prefrontal cortex | Research

The takeaway

THC infused into the mouse prefrontal cortex disrupted walking by increasing inhibitory neuron activity and triggering a surprising burst of the brain's own endocannabinoid release during movement.

Neuroscientists studying cannabis mechanisms, researchers investigating motor impairment, and those interested in prefrontal cortex function.

THC triggered movement-locked endocannabinoid release that amplified impairment

What the researchers found

THC increased GABAergic (inhibitory) neuron activity in the medial prefrontal cortex before movement initiation, shifting the excitatory/inhibitory balance. Unexpectedly, THC also induced a transient, movement-triggered potentiation of endocannabinoid release that further disrupted motor behavior.

Why it matters

Cannabis impairment is well known but poorly understood at the neural circuit level. This study identifies a specific mechanism in the prefrontal cortex and reveals that THC paradoxically triggers the brain's own cannabinoid system to amplify impairment.

The numbers in context

THC was infused directly into the medial prefrontal cortex. Machine learning classified discrete walking kinematic features. THC predominantly increased GABAergic activity preceding walk initiation. Movement-locked endocannabinoid release was time-locked and transient.

How the study worked

Machine learning behavioral classification of mouse movements combined with fiber photometry, optogenetics, and endocannabinoid biosensors to measure neural activity and eCB dynamics in the medial prefrontal cortex during THC exposure.

What this study cannot tell us

Preprint (not yet peer-reviewed). Direct brain infusion of THC does not replicate normal cannabis consumption routes. Mouse motor behavior may not fully translate to human impairment patterns.

How to read the evidence

Sophisticated multi-technique animal study with direct neural measurements, but preprint status and direct brain infusion limit translational conclusions.

When this study was published

2025 preprint (bioRxiv, not yet peer-reviewed).

The bigger picture

Understanding exactly how THC impairs motor behavior at the circuit level could inform development of treatments for cannabis-related impairment and improve our understanding of the brain's endocannabinoid system.

Questions still open

Does this movement-induced endocannabinoid potentiation occur in humans? Could blocking this cascade prevent THC-related motor impairment?

Common questions

How does THC impair movement?

This study found THC shifts the brain's prefrontal cortex toward more inhibition before movement begins, disrupting walking. It also triggers a burst of the brain's own cannabinoids during movement that worsens the impairment.

Does the brain release its own cannabinoids in response to THC?

Surprisingly, yes. This study found that THC induced a transient, movement-triggered release of endocannabinoids in the prefrontal cortex, which further disrupted motor behavior through CB1 receptor activation.

Read the original research

Behavioral Decoding Reveals Cortical Endocannabinoid Potentiation during Δ9-THC Impairment.

bioRxiv : the preprint server for biology

View on PubMed ↗Publisher’s paper ↗

Citation

English, Anthony; Marcus, David; Yadav, Khushi; Elkhouly, Yassin; Levy, Allan; Corbit, Victoria; Ask, Maddie; Scedberg, Anika; Poces-Ball, Jordan; Uittenbogaard, Fleur; Simons, Rayna; Witten, Ilana; Zweifel, Larry; Land, Benjamin; Stella, Nephi; Bruchas, Michael R. (2025). Behavioral Decoding Reveals Cortical Endocannabinoid Potentiation during Δ9-THC Impairment.. bioRxiv : the preprint server for biology. https://doi.org/10.1101/2025.09.26.678874