Behavioral flexibility allows individuals to adapt to situations in which rewards and goals change. Potentially addictive drugs may impair flexible decision-making by altering brain mechanisms that compute reward expectancies, thereby facilitating maladaptive drug use. To investigate this hypothesis, we tested the effects of oxycodone exposure on…

This study examines the role of stimulus duration in learning and memory formation of honeybees ("Apis mellifera"). In classical appetitive conditioning honeybees learn the association between an initially neutral, conditioned stimulus (CS) and the occurrence of a meaningful stimulus, the unconditioned stimulus (US). Thereby the CS…

Adolescent rats exhibit impaired extinction retention compared to pre-adolescent and adult rats. A single nonreinforced exposure to the conditioned stimulus (CS; a retrieval trial) given shortly before extinction has been shown in some circumstances to reduce the recovery of fear after extinction in adult animals. This study investigated whether a…

Recent research shows that while initial learning is dependent on "N"-methyl-D-aspartate receptors (NMDArs), relearning can be NMDAr-independent. In the present study we examined whether this switch also occurs following forgetting. The developing animal exhibits much more rapid rates of forgetting than adults, so infant rats were used. It was…

Pairing a previously neutral conditioned stimulus (CS; e.g., a tone) to an aversive unconditioned stimulus (US; e.g., a footshock) leads to associative learning such that the tone alone comes to elicit a conditioned response (e.g., freezing). We have previously shown that an extinction session that occurs within the reconsolidation window…

Signaling via the epidermal growth factor receptor (EGFR) pathway has emerged as one of the key mechanisms in the development of the central nervous system in "Drosophila melanogaster." By contrast, little is known about the functions of EGFR signaling in the differentiated larval brain. Here, promoter-reporter lines of EGFR and its most prominent…

Sign- and goal-tracking are differentially associated with drug abuse-related behavior. Recently, it has been hypothesized that sign- and goal-tracking behavior are mediated by different neurobehavioral valuation systems, including differential incentive salience attribution. Herein, we used different conditioned stimuli to preferentially elicit…

Protein degradation is known to affect memory formation after extinction learning. We demonstrate here that an inhibitor of protein degradation, MG132, interferes with memory formation after extinction learning in a classical appetitive conditioning paradigm. In addition, we find an enhancement of memory formation when the same inhibitor is…

During extinction animals experience that the previously learned association between a conditioned stimulus (CS) and an unconditioned stimulus (US) no longer holds true. Accordingly, the conditioned response (CR) to the CS decreases. This decrease of the CR can be reversed by presentation of the US alone following extinction, a phenomenon termed…

Learning complex skills is driven by reinforcement, which facilitates both online within-session gains and retention of the acquired skills. Yet, in ecologically relevant situations, skills are often acquired when mapping between actions and rewarding outcomes is unknown to the learning agent, resulting in reinforcement schedules of a stochastic…

Learning to ignore irrelevant stimuli is essential to achieving efficient and fluid attention, and serves as the complement to increasing attention to relevant stimuli. The different cholinergic (ACh) subsystems within the basal forebrain regulate attention in distinct but complementary ways. ACh projections from the substantia innominata/nucleus…

Cyclic AMP response element binding protein (CREB) plays a critical role in fear memory formation. Here we determined the role of CREB selectively within the amygdala in reconsolidation and extinction of auditory fear. Viral overexpression of the inducible cAMP early repressor (ICER) or the dominant-negative mCREB, specifically within the lateral…

Extinction reduces fear to stimuli that were once associated with an aversive event by no longer coupling the stimulus with the aversive event. Extinction learning is supported by a network comprising the amygdala, hippocampus, and prefrontal cortex. Previous studies implicate a critical role of GABA in extinction learning, specifically the GAD65…

Throughout the animal kingdom, the inhibitory neurotransmitter ?-aminobutyric acid (GABA) is a key modulator of physiological processes including learning. With respect to associative learning, the exact time in which GABA interferes with the molecular events of learning has not yet been clearly defined. To address this issue, we used two…

There are significant sex differences in vulnerability to develop fear-related anxiety disorders. Females exhibit twice the rate of post-traumatic stress disorder (PTSD) as males and sex differences have been observed in fear extinction learning in both humans and rodents, with a failure to inhibit fear emerging as a precipitating factor in the…