Pavlovian aversive conditioning is an evolutionarily well-conserved adaptation enabling organisms to learn to associate environmental stimuli with biologically aversive events. However, mechanisms underlying preferential (or enhanced) Pavlovian aversive conditioning remain unclear. Previous research has suggested that only specific stimuli that have threatened survival across evolution (e.g., s...

Memory phases, dependent on different neural and molecular mechanisms, strongly influence memory performance. Our understanding, however, of how memory phases interact is far from complete. In Drosophila, aversive olfactory learning is thought to progress from short-term through long-term memory phases. Another memory phase termed anesthesia resistant memory, dependent on the radish gene, influ...

Associative strength between conditioned stimulus (CS) and unconditioned stimulus (US) is thought to determine learning efficacy in classical conditioning. Elucidation of the neuronal mechanism that underlies the association between CS and US in the brain is thus critical to understand the principle of memory formation. With a simple brain organization, the Drosophila larva provides an attracti...

Elucidation of reinforcement mechanisms in associative learning is an important subject in neuroscience. In mammals, dopamine neurons are thought to play critical roles in mediating both appetitive and aversive reinforcement. Our pharmacological studies suggested that octopamine and dopamine neurons mediate reward and punishment, respectively, in crickets, but recent studies in fruit-flies conc...

The ability to flexibly adapt responses to changes in the environment is important for survival. Previous research in humans separately examined the mechanisms underlying acquisition and extinction of aversive and appetitive conditioned responses. It is yet unclear how aversive and appetitive learning interact on a neural level during counterconditioning in humans. This functional magnetic reso...

Learning to predict rewarding and aversive outcomes is based on the comparison between predicted and actual outcomes (prediction error: PE). Recent electrophysiological studies reported that during a Pavlovian procedure some dopamine neurons code a classical PE signal while a larger population of dopaminergic neurons reflect a "salient" prediction error (SPE) signal, being excited both by unpre...

We study a framework where agents have to avoid aversive signals. The agents are given only partial information, in the form of features that are projections of task states. Additionally, the agents have to cope with non-determinism, defined as unpredictability on the way that actions are executed. The goal of each agent is to define its behavior based on featureaction pairs that reliably avoid...

Neonicotinoid insecticides can impair bee learning and memory--cognitive features that play a key role in colony fitness because they facilitate foraging. For example, the commonly used neonicotinoid imidacloprid reduces honey bee olfactory learning. However, no studies have previously determined whether imidacloprid can impair aversive associative learning, although such learning should enhanc...

The Neurobiological Mechanisms Underlying the Sensitization of Pain and Learning. (April 2001) Brianne Colemarie Patton Department of Psychology Texas A&M University Fellows Advisor: Dr. James Grau Department of Psychology Why animals learn and how they do so has long been a topic of inquiry and research. Recently, King, Joynes, Meagher and Grau (1996) shov:ed that exposure to a mild aversive e...

The locus coeruleus norepinephrine (LC-NE) system plays a broad role in learning and memory. Here we begin with an overview of the LC-NE system. We then consider how both direct and indirect manipulations of the LC-NE system affect cued and contextual aversive learning and memory. We propose that NE dynamically modulates Pavlovian conditioning and extinction, either promoting or impairing learn...