Biology subjects

Liley, A. E.

Publications and source records attributed to Liley, A. E..

4 recordsLinked to original sources

bioRxiv2022

Divergent risky decision-making and impulsivity behaviors in two Lewis substrains of rats with low genetic difference

Substance use disorder (SUD) is associated with a cluster of cognitive disturbances that engender vulnerability to ongoing drug seeking and relapse. Two of these endophenotypes--risky decision-making and impulsivity--are amplified in individuals with substance use disorder and are augmented by repeated exposure to illicit drugs. Identifying genetic factors underlying variability in these traits is critical for early identification, prevention, and treatment of SUD-vulnerable individuals. Here, we compared risky decision-making and different facets of impulsivity between two fully inbred substrains of Lewis rats--LEW/NCrl and LEW/NHsd. We performed whole genome sequencing of both substrain to identify almost all relevant variants. We observed substantial differences in risky decision-making and impulsive behaviors. Relative to LEW/HHsd, the LEW/NCrl substrain accepts higher risk options in a decision-making task and higher rates of premature responses in the differential reinforcement of low rates of responding (DRL) task. These phenotypic differences were more pronounced in females than males. We defined a total of [~]9,000 polymorphisms between these substrains at 40X whole genome short-read coverage. Roughly half of variants are located within a single 1.5 Mb region of chromosome 8, but none impact protein-coding regions. In contrast, other variants are widely distributed, and of these 38 are predicted to cause protein-coding variants. In conclusion, Lewis rat substrains differ significantly in risk-taking and impulsivity and only a small number of easily mapped variants are likely to be causal. Sequencing combined with a reduced complexity cross (RCC) should enable identification of one or more variants underlying multiple complex addiction-relevant traits.

genomics↗

bioRxiv2022

Lateral Orbitofrontal Cortex and Basolateral Amygdala Regulate Sensitivity to Delayed Punishment during Decision-making

In real-world decision-making scenarios, negative consequences do not always occur immediately after a choice. This delay between action and outcome drives the underestimation, or "delay discounting", of punishment. While the neural substrates underlying sensitivity to immediate punishment have been well-studied, there has been minimal investigation of delayed consequences. Here, we assessed the role of lateral orbitofrontal cortex (LOFC) and basolateral amygdala (BLA), two regions implicated in cost/benefit decision-making, in sensitivity to delayed vs immediate punishment. The delayed punishment decision-making task (DPDT) was used to measure delay discounting of punishment in rodents. During DPDT, rats choose between a small, single pellet reward and a large, three pellet reward accompanied by a mild foot shock. As the task progresses, the shock is preceded by a delay that systematically increases or decreases throughout the session. We observed that rats avoid choices associated with immediate punishment, then shift preference toward these options when the punishment is delayed. LOFC inactivation did not influence choice of rewards with immediate punishment, but decreased choice of delayed punishment. We also found that BLA inactivation reduced choice of delayed punishment, but this was only evident when punishment was initially delivered immediately after a choice, then preceded by a delay as the task progressed. Therefore, both LOFC and BLA contribute to the delay discounting of punishment, and may serve as promising therapeutic targets to improve sensitivity to delayed punishment during decision-making. Significance StatementNegative consequences occurring after a delay are often underestimated, which can lead to maladaptive decision-making. While sensitivity to immediate punishment during reward-seeking has been well-studied, the neural substrates underlying sensitivity to delayed punishment remain unclear. Here, we used the Delayed Punishment Decision-making Task to determine that lateral orbitofrontal cortex and basolateral amygdala both regulate the discounting of delayed punishment, suggesting that these regions may be potential targets to improve decision-making in psychopathology.

neuroscience↗

bioRxiv2021

The effects of epigallocatechin gallate and caffeine on risky decision-making

Epigallocatechin-3-gallate (EGCG) and caffeine are the two primary compounds found in green tea. While EGCG has anxiolytic and anti-inflammatory effects, its acute effects on cognition are not well understood. Furthermore, despite widespread green tea consumption, little is known about how EGCG and caffeine co-administration impact behavior. Here, we investigated the effects of multiple doses of either EGCG or caffeine on a rat model of risk-taking. This was assessed using the risky decision-making task (RDT), in which rats choose between a small, safe reward and a large reward with escalating risk of mild footshock. Rats were tested in RDT after acute systemic administration of EGCG, caffeine, or joint EGCG and caffeine. EGCG caused a dose dependent reduction in risk-taking without affecting reward discrimination or task engagement. Caffeine did not impact risk taking, but elevated locomotor activity and reduced task engagement at high doses. Finally, exposure to both EGCG and caffeine had no effect on risk-taking, suggesting that low-dose caffeine is sufficient to mask the risk-aversion caused by EGCG. These data suggest EGCG as a potential therapeutic treatment for psychological disorders that induce compulsive risky decision-making.

neuroscience↗

bioRxiv2020

Impact of Cannabinoid Type 1 Receptor Modulation on Risky Decision-Making

Recent changes in policy regarding cannabis in the U.S. have been accompanied by an increase in the prevalence of cannabis use and a reduction in the perceived harms associated with consumption. However, little is understood regarding the effects of cannabinoids on cognitive processes. Given that deficient risk-taking is commonly observed in individuals suffering from substance use disorders (SUDs), we assessed the impact of manipulating cannabinoid type 1 receptors (CB1Rs; the primary target for {Delta}9-tetrahydrocannabinol in the brain) on punishment-based risk-taking using the risky decision-making task (RDT) in male Long-Evans rats. The RDT measures preference for small, safe rewards over large, risky rewards associated with an escalating chance of foot shock. Systemic bidirectional CB1R manipulation with a CB1R agonist, CB1R antagonist, and FAAH inhibitor (which increases overall endocannabinoid tone) did not alter overt risk-taking in the RDT. Interestingly, direct CB1R agonism, but not indirect CB1R stimulation or CB1R blockade, resulted in reduction in latency to make risky choices while not altering safe choice latency. Our findings suggest that CB1R activation expedites engagement in punishment based risk-taking without affecting overall preference for risky vs. safe options. This indicates that risk preference and rate of deliberation for risk-taking are influenced by distinct neural substrates, an important consideration for development of precise treatments targeting the aberrant risk-taking typical of SUD symptomology.

animal behavior and cognition↗