Figure 2.1. The motion behavior in Hydra resembles a series of flips, as shown in the sequence at the beginning on the left. The tiny black dot in the area between the tentacles in the character on the far right is the mouth of the animal. When taking (feeding) food particles with coordinated movements of tentacles in the mouth. Santiago Ramon y Cajal (Figure 1.14) is attributed to the doctrine of neurons, one of the basic assumptions of brain research that “the nervous system is composed of many nerve units (neurons) that are anatomical and genetically independent.” It is important to realize that the idea that the body is composed of cells dates back only to 1839, with the use of light microscopes and tissue staining techniques that, for the first time in human history, showed the details of living cells. Llinas, R. R. The intrinsic electrophysiological properties of mammalian neurons: an overview of the function of the central nervous system. Science 242, 1654-1664 (1988). The basic anatomy and physiology of neurons are known with regard to the teaching of neurons, which says that the element of neuronal function is the individual neuron. The concept of cooperative neuronal mass, which exists through synaptic connections between participating neurons, is complementary to this teaching (fig.
3). In this hierarchical perspective, population activity coexists with the action potential traits of individual neurons in the form of common activity patterns distributed throughout space, which occupy large areas of the cortex, exhibit sudden tolerances and shifts, and last small fractions of a second. These wave packets have only recently become available for measurements with large arrays of electrodes and amplifiers. They form the basis of this new approach. Synapse Instead of contact between two neurons, there is a transmission barrier that can allow transmission. There is, however, an ironic ending in the history of the Cajal. The great controversy over the separation of neurons continues to this day. Cajal seemed to have solved the question forever when he showed that Axon had free nerve endings. However, recent findings show that many of the transmission points between nerve cells are not chemical synapses, but electrically continuous tissues called Gap Junctions. . . .