The human brain is extremely complex. Even now, when we know so much about the brain of not only humans but also a number of animals, we are apparently still very far from understanding the physiological mechanisms of many mental functions. We can say that these questions are only just on the agenda of modern science. First of all, it concerns such mental processes as thinking, perception of the surrounding world and memory, and many others. At the same time, the main problems that will have to be solved in the millennium are now clearly defined.