Böcker av Nair Anu G

The ability to sense and react-to external environment is a crucial element of life. Transformationof environmental stimuli to organismal response involves complex computationswhich become increasingly sophisticated as an organism is higher up the tree of life. Inthe animal kingdom, starting from lower level phyla except for Porifera, the elements involvedin these computations show a functional organization to form the nervous systemwith varying degree of complexity, possibly, to increase the repertoire and efficiency of thestimulus-response transformation. Given the dynamic nature of the external environment,it is crucial that animals should be able to associate novel environmental stimuli to appropriateresponses, and also reconfigure the existing stimuli-response transformations in thelight of newer environmental realities. "Learning" encapsulates these abilities of an organismto create novel association or update existing associations. One of the various formsof learning is reward learning and it is fundamental to several animal behaviors. In rewardlearning, if a stimulus or a stimulus-response pair is followed by a rewarding experiencethen its perceived salience increases and this results in an association between the stimulus,response and the reward. Using such associations built upon past experiences, an organismcould predict a possible reward if a specific stimulus is present in a given environmentalcontext and how it should respond to achieve this reward. In other words, reward learning isa process of creating or updating stimuli-response transformations that is guided by rewardas a teaching signal.