Exclusive Interview: Animal Model of Adolescent Cannabis Abuse Reveals Long-Term Prefrontal Cortex Alterations

Professor Edward Korzus is an Assistant Professor, Department of Psychology, at the University of California Riverside. In this exclusive SelectScience interview, he discusses his laboratory’s research into adolescent cannabis abuse, and the different methodologies and technologies used to investigate prefrontal cortex circuitry in animal models.

Investigating Neural Circuit Response
“Our laboratory is investigating the role of prefrontal cortex in fear discrimination,” said Prof Korzus. “We’ve generated a number of methodologies that allow us to selectively manipulate neurons in the prefrontal circuit and selectively change the capacity for long-term encoding of new information, without disconnecting them from the rest of the circuit.”

Modeling Cannabis Abuse
Current research in the Korzus Laboratory investigates the effects of adolescent cannabis abuse, as Prof Korzus explains: “We tested animal models for adolescent cannabis abuse using electrophysiological methodology, to see how the prefrontal circuit is affected by adolescent cannabis abuse. For this, we generated an animal model which was treated with cannabinoid during rodential adolescence, and we looked at the integrity of the neural circuit in the prefrontal cortex.”
“We use an electrophysiological system that we purchased from Molecular Devices. It has excellent capacities and options. For visualization of the network of the brain slices, we use a confocal laser scanning microscope from Olympus, which is extremely useful, not only for electrophysiology but also for other applications.”

Effects on the Prefrontal Cortex
“We tested the capacity to express a form of long-term plasticity called LTD (long term depression); this type of neuroplasticity depends on the endocannabinoid system. What we see is that animals that have been treated with cannabinoid during adolescence have long-term changes in the integrity of the prefrontal cortex.”

The Importance of Investigating Cannabis Abuse
“The prefrontal cortex is a brain region that holds the circuit for decision making, so it’s critical for cognitive functioning. Such alteration in the prefrontal cortex could have long-term effects on behavior. It has been reported from many laboratories that adolescence cannabis abuse is linked to an increased risk for dependence on other drugs, depression, anxiety, as well as psychosis. So this is why these studies are extremely important, as they demonstrate that adolescent cannabis abuse could affect our brains for a long period of time, and this type of alteration may have an effect on homeostatic regulation of the prefrontal circuit.”

This research could lead to new advances in understanding the effects of adolescent cannabis abuse on the brain: “Probably the most critical direction that we undertake at this moment is to find correlates between alterations in the brain circuit at the physiological level with behavioral changes,” said Prof Korzus.