Although the glia was discovered before neurones, its importance in the function of the nervous system was neglected for a long time. The tide has turned, however, during the last twenty years, and a multitude of seminal discoveries have been made. All in all general neurobiology reluctantly agreed that glial cells are as important as neurones for brain function and glia cannot be bluntly disregarded anymore. This has changed our perception of how the brain is organized, and how the development, life and death of neural circuits are controlled. Indeed, astrocytes appear to be omnipotent neural progenitors, and the same astrocytes mostly control synaptogenesis, define microarchitecture of the brain, and form neuronal-glial-vascular units. In fact it is astrocytes which brunt the all-important task of integrating various cells and structures of the brain into individual units, simultaneously connecting these units into the functional entity. Astrocytes are capable of sensing and releasing transmitter, thus being fully involved in ongoing brain chemical transmission, yet in addition the astroglial syncytium, connected through gap junction communication pathways, allows an alternative and sophisticated intercellular communication route, which permits direct translocation of ions, metabolic factors and second messengers. The resulting potential for parallel processing and integration is significant and might easily be larger, but also fuzzier, than the binary coded electrical communication within the neuronal networks. In a way, the neuronal networks may be seen as highly specialized elements of rapid delivery of information, whereas astroglial cells may represent the true substrate (or 'substance', as Virchow would have called it) for information processing, integration and storage. Indeed, the number of glia, both in absolute terms and relative to the number of neurones, increases dramatically on the phylogenetic scale, and the complexity of glial cells is the greatest in the human brain, where the intelligence also dwells.
The extremely elaborated panglial syncytium is a true neural reticulum, which, at least in numerical terms prevails over discreet neuronal networks; although both internally connected glial syncytium and discreet neuronal networks peacefully coexist within the brain. Shall we anticipate even more exciting discoveries which eventually can challenge the role of neurones as sole origins of intellect and cognition? Can the neuronal doctrine withstand the challenge from glial cells? This is the future, which holds a definite answer to this question.
Was this article helpful?
This guide will help millions of people understand this condition so that they can take control of their lives and make informed decisions. The ebook covers information on a vast number of different types of neuropathy. In addition, it will be a useful resource for their families, caregivers, and health care providers.