Neuroglia of the central nervous system (CNS), represented by cells of neural (astrocytes, oligodendrocytes and
NG2 glial cells) and myeloid (microglia) origins are fundamental for homeostasis of the nervous tissue. Astrocytes are
critical for the development of the CNS, they are indispensable for synaptogenesis, and they define structural organisation
of the nervous tissue, as well as the generation and maintenance of CNS-blood and cerebrospinal fluid-blood barriers.
Astroglial cells control homeostasis of ions and neurotransmitters and provide neurones with metabolic support.
Oligodendrocytes, through the process of myelination, as well as by homoeostatic support of axons provide for
interneuronal connectivity. The NG2 cells receive direct synaptic inputs, and might be important elements of adult
remyelination. Microglial cells, which originate from foetal macrophages invading the brain early in embryogenesis,
shape the synaptic connections through removing of redundant synapses and phagocyting apoptotic neurones. Neuroglia
also form the defensive system of the CNS through complex and context-specific programmes of activation, known as
reactive gliosis. Many neurological diseases are associated with neurogliopathologies represented by asthenic and atrophic
changes in glial cells that, through the loss or diminution of their homeostatic and defensive functions, assist evolution of
pathology. Conceptually, neurological and psychiatric disorders can be regarded as failures of neuroglial homeostatic/
defensive responses, and, hence, glia represent a (much underappreciated) target for therapeutic intervention.