Summary
Learning can be defined as a change in capacity for behavior as a result of particular kinds of experience. Learning can be relatively simple, as is the case in habituation or discrimination paradigms, but also rather complex, which is the case in feature discrimination procedures. The brain activity of the learning subject can be examined in order to find out more about the brain processes involved in learning. Furthermore, by comparing the brain activity of humans and rats, it is possible to gather new information on the functioning of the mammalian brain, which in turn may be used to develop, test, and improve models of cognitive functions and, in a later stadium, models of cognitive dysfunctions. The electrophysiology of humans and rats as induced in different learning paradigms was directly compared in this thesis.
The experiments revealed similarities in cognitive processing as reflected by the so-called event-related potential (ERP) components of humans and rats. The relatively early ERP components showed short-term amplitude decrements in both species in the habituation experiment and the later ERP components revealed long-term decrements that reflect habituation. Furthermore, the P3 component of humans and rats was enlarged in response to target stimuli compared to standard stimuli in a discrimination task. Finally, the feature discrimination task showed that in both humans and rats, the N2 component was more negative when the subjects did not have to respond than when they did have to make a response.
In conclusion, the N1, N2, and P3 components of rats as elicited during learning tasks share some characteristics with the human N1, N2, and P3 component. This supports the notion of the rat being an appropriate animal model for the study of the electrophysiological correlates of cognitive processes as induced in traditional learning paradigms.
