Interest in instrumental learning in earthworms dates back to 1912 when Yerkes concluded that they can learn a spatial discrimination in a T-maze. Rosenkoetter and Boice determined in the 1970s that the "learning" that Yerkes observed was probably chemotaxis and not learning at all. We examined a different form of instrumental learning: the ability to learn both to escape and to avoid an aversi...

The idea of aversion therapy is that if you give someone an unpleasant experience every time he does a particular act he will stop wanting to perform that act. Although still in the developmental stage this new form of treatment, which originated with Pavlov, has already benefited many people troubled with sexual problems. Dr. Michael J. Raymond, Consultant Psychiatrist, who is using this techn...

Dopamine is thought to regulate learning from appetitive and aversive events. Here we examined how optogenetically-identified dopamine neurons in the lateral ventral tegmental area of mice respond to aversive events in different conditions. In low reward contexts, most dopamine neurons were exclusively inhibited by aversive events, and expectation reduced dopamine neurons' responses to reward a...

The understanding of how the reinforcement is represented in the central nervous system during memory formation is a current issue in neurobiology. Several studies in insects provide evidence of the instructive role of biogenic amines during the learning and memory process. In insects it was widely accepted that dopamine (DA) mediates aversive reinforcements. However, the idea of DA being exclu...

Ivan Pavlov, classical conditioning involves the pairing of neutral stimuli with aversive or appetitive cues. This results in learning. Formally neutral stimuli now predict salient events. One form of Pavlovian conditioning is fear conditioning, the primary associative learning mechanism involved in aversive emotional learning. It is through this process that we learn to be fearful of people, a...

Learning what to approach, and what to avoid, involves assigning value to environmental cues that predict positive and negative events. Studies in animals indicate that the lateral habenula encodes the previously learned negative motivational value of stimuli. However, involvement of the habenula in dynamic trial-by-trial aversive learning has not been assessed, and the functional role of this ...

The intent of this study was to investigate neurochemical and behavioural effects of aversive stimulation and the impact of auditory background noise. Using in vivo microdialysis, hippocampal acetylcholine was extracted and subjected to HPLC analysis while male Wistar rats were exposed to aversive stimulation similar to that used in conventional procedures for aversive conditioning. Three group...