decision neuroscience
jamie donahey roitman
RESEARCH
Adolescence is a period marked by increasingly risky choices, often including the recreational use of alcohol, marijuana, or stimulants. Prefrontal cortex - a core component of executive control circuitry - undergoes extensive development during this period. Adolescence substance use thus has the potential to disrupt the normal developmental trajectory of prefrontal cortex, with potentially long-term consequences for decision-making. Several lines of our research explore the longitudinal impact of adolescent substance use on different aspects of impulsive choice.
Alcohol and risk-preference
​We have found that patterns of activity in the orbitofrontal region of prefrontal cortex (OFC) correlate with subjective risk-preference in adult animals. To explore whether adolescent alcohol consumption alters risk-preference and OFC activity, we allowed adolescent animals to voluntarily consume "jello shots" daily and measured how their preference for large-risky food rewards relative to small-certain ones was affected both during adolescence and adulthood. We found that moderate alcohol consumption during adolescence is associated with increased risk-preference in adolescence and adulthood, as well as blunted OFC responses to rewards in adulthood. This change does not seem to be due to deficits in learning or cognitive flexibility, as adolescent alcohol consumption does not affect reversal learning. Ongoing work uses qPCR to examine how changes in dopaminergic and cholinergic systems may contribute to these alterations in OFC responses.
Methylphenidate and delay discounting
Prescription psychostimulants are widely abused by adolescents for their cognitive enhancement or stimulant properties. We are investigating how OFC encodes rewards of different sizes and delays during adolescence and adulthood, as well as how methylphenidate (MPH, Ritalin) use may alter OFC activity and impulsive choices. The goal of these studies is to understand the role of OFC in the development of the ability to wait for delayed, larger rewards and the effects of MPH on this neural signaling.
Cannabinoids and risk-preference
Marijuana is the most widely used illicit drug among adolescents, with increasing prevalence as its changing legal status supports greater availability. We are interested in how daily cannabinoid use, in male and female animals, affects risk-preference and signaling of risky rewards in the medial prefrontal cortex (mPFC) during adulthood. These studies combine adolescent endocannabinoid agonist treatment with electrophysiological recordings in adulthood. We are also investigating epigenetic changes following cannabinoid treatment that persist into adulthood.
Adolescence
and impulsive
choice
Techniques
Cognitive behavioral tasks
Risk-preference
Reversal learning
Go/NoGo
Sustained attention
Delay discounting
Electrophysiology
Single unit recordings of prefrontal cortex and striatum
Pharmacology
Adolescent treatment with stimulants, cannabinoids
Voluntary consumption of alcohol
Brain stimulation reward
Chemogenetics
Excitatory and inhibitory DREADDS in prefrontal cortex
qPCR
Alterations in message for dopaminergic, cannabinoid, GABA-ergic and cholinergic receptors following adolescent substance use
Science through art
Baking Bad: Good gingerbread gone wrong