PT  - JOURNAL ARTICLE
AU  - Catarina Albergaria
AU  - N. Tatiana Silva
AU  - Dana Darmohray
AU  - Megan R. Carey
TI  - Cannabinoids modulate associative cerebellar learning via alterations in behavioral state
AID  - 10.1101/511113
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 511113
4099  - http://biorxiv.org/content/early/2020/09/27/511113.short
4100  - http://biorxiv.org/content/early/2020/09/27/511113.full
AB  - Cannabinoids are notorious and profound modulators of behavioral state. In the brain, endocannabinoids act via Type 1-cannabinoid receptors (CB1) to modulate synaptic transmission and mediate multiple forms of synaptic plasticity. CB1 knockout (CB1KO) mice display a range of behavioral phenotypes, in particular hypoactivity and various deficits in learning and memory, including cerebellumdependent delay eyeblink conditioning. Here we find that the apparent effects of CB1 deletion on cerebellar learning are not due to direct effects on CB1-dependent plasticity, but rather, arise as a secondary consequence of altered behavioral state. Hypoactivity of CB1KO mice accounts for their impaired eyeblink conditioning across both animals and trials. Moreover, learning in these mutants is rescued by walking on a motorized treadmill during training. Finally, cerebellar granule cell-specific CB1KOs exhibit normal eyeblink conditioning, and both global and granule cell-specific CB1KOs display normal cerebellum-dependent locomotor coordination and learning. These findings highlight the modulation of behavioral state as a powerful independent means through which individual genes contribute to complex behaviors.Competing Interest StatementThe authors have declared no competing interest.