Some aspects of the communicational and computational organization of the brain.

Some features of the morphofunctional organization of the CNS have been analysed. Different types of hierarchical organization have been recognized, each of which could deeply affect the circulation (communicational aspect) and elaboration (computational aspect) of information. These two aspects have been discussed on the basis of the existence of two types of electrochemical transmission in the CNS: wiring and volume transmission. By evaluating the CNS operations at different levels of analysis a 'computational hierarchical organization' has been delineated. This concept is very relevant to the understanding of the 'computational power' of the brain (Agnati & Fuxe 1984, Conrad 1985a). In fact, it leads to the distinction between horizontal and vertical elaboration of information. The hypothesis is introduced that in the vertical elaboration of information a central role may be played by the neuronal membrane. In fact, this structure can not only be influenced by the extra- and intracellular signals, but also effectively interconvert the electrical coding into the chemical coding of information. These aspects are discussed in the frame of the possible organization of the membrane into 'domains', each domain being a patch of membrane in which pre-selected molecular movements are possible, resulting in molecular interactions. The movement of a molecule outside its domain is considered energetically unfavourable. The possible formal treatment of this hypothesis is mentioned in Conrad's work (1985b).