Lasting Decrease of Corticostriatal Coherence in Rats After Acute Exposure to Vapourized ∆9-Tetrahydrocannabinol
- Bryan Jenkins
In this study, we assessed changes in neural circuit dynamics in rats exposed to vapourized ∆9-tetrahydrocannabinol (THC). We hypothesized that THC would reduce coherence between cortical and striatal brain regions. Results showed vapourized THC exposure led to acute neurophysiological changes consistent with some of the known effects of cannabis and symptomatic electrophysiological activity in patients with schizophrenia.
Effects of Adolescent Nicotine Exposure on Neurodevelopment and Cognition
- Jude Frie
Adolescent nicotine exposure is an increasing concern with the emergence of electronic cigarette devices (e.g. vaping), highlighting the importance of considering long-term behavioural consequences of adolescent exposure. Male Sprague-Dawley rats (n=16, 8/group) were treated daily with 1.0 mg/kg subcutaneous nicotine from post-natal days 28-42. Upon adulthood, rats underwent behavioural assessments: novel object preference as a measure of short- and long-term memory, conditioned avoidance response (CAR) as a measure of aversive behaviour acquisition and elevated plus maze as a measure of anxiety like behaviour. Adolescent nicotine-treated rats displayed a significant, but selective, impairment of short-term memory (5-minute delay). A significant within-animal delay by drug interaction (F(1,14)=4.748, p=0.047) was observed; between-group analyses showed that nicotine-treated animals displayed significantly decreased discrimination ratio compared to vehicle-treated animals (p=0.011). No group differences were observed in acquisition or extinction of CAR nor were any significant differences seen in elevated plus maze. In the future we will look at fear conditioning, pre-pulse inhibition, and electrophysiological consequences of adolescent nicotine exposure.
Circadian Rhythm Disruptions on Alcohol Consumption
- Abanoub Rizk
Circadian rhythms can be disrupted due to shiftwork, travel, and changes in seasons. These disruptions induce desynchrony between the environment and the internal circadian rhythm and have been linked to a higher likelihood of binge drinking. In addition, ClockΔ19 mouse models, with altered circadian rhythms, exhibit amplified sensitivity to rewarding substances, such as alcohol, compared to wild type (WT), suggesting that they may be at a greater risk for addiction. Our aim is to investigate the effects of environmental and genetic circadian rhythm disruptions on alcohol consumption in a gene-environment interaction study.
Automated Two-Bottle Choice Test
- Jude Frie
Two-bottle choice tests are a widely used paradigm in rodents to determine preference between two liquids, with utility for testing animal models of addiction, depression and anhedonia. Our lab has created a 3D-printed, Arduino controlled two-bottle choice test that automatically reads and records drinking behaviour in rats to allow for detailed analysis of their drinking microstructure. Our design uniquely incorporates hydrostatic depth sensors to allow for real-time volumetric measurements in addition to traditional beam break lick sensing, allowing for licking and drinking microstructure analysis. The goal of this design is to provide a user friendly, affordable, and accurate apparatus that can study unique, complex behaviours without requiring the purchase of specialized scientific equipment or software. Its applications range from studying alcohol preference in addiction to sugar preference in motivational deficits and reward characterization.