[Synchronization and propagation of electrical potentials in neural networks of the brain cortex]

Abstract

On the basis of the published data the scheme is proposed which explains the spread and synhronization of oscillatory activity in cortex. The main property of the neocortex is the existence of vertically oriented functional columns. Within and between the neuronal columns exist a feedforward and feedback morphological and functional connections. At the certain conditions inside the single module temporal windows are created using inhibitory process, and a synchronized activity can be generated of variable frequency (oscillations). The activity in the columns is enhanced by the synchronous involvement of great amount of neurons which is expressed in the form of local field potentials of high amplitude. Further the information about arisen in a single generator activity is transmitted through direct links to the nearby generator or to the group of such generators. In the nearby generator the activity increases and is transferred to the next generator. At the same time the signal is transmitted through feedback to the primary generator, and the activity is terminated until the next cycle will be initiated and so on along the cortex. The most important notion is that in the transfer of activity from one generator to another is involved a small number of elements. The major part of recorded oscillations of different frequency or epileptiform discharges, is not transmitted via the brain, but is generated in each module according to the characteristics transferred to it. The generation of epileptiform spikes occurs in cases when balance of inhibition determined by GABA A and GABA B receptors is disturbed.