Astrocytes Store for Memory and Cognition

Abstract

In humans, protoplasmic astrocytes are found with high density in the cortex and hippocampus (both parts responsible for memory and cognition) and each astrocyte is in contact with two million of synapses. Astrocytes are responsible for the synaptogenesis and the removal of synapses, which is the basis of learning and memory. The synaptogenesis increases sevenfold with the addition of astrocytes to the neuronal culture media. Astrocytes divide the brain and spinal cord into separate domains, including neurons, synaptic terminals and blood vessels and are integrated by protoplasmic astrocytic appendages. Astrocytes are also responsible for the formation of a single, wide lattice called the syncytium, which can store and process a high volume of information and transmit voluminous messages through intracellular gap junctions. It is relatively slow and is in turn a reason for thinking and gradual use of the information stored in memory. Astrocytes are mainly involved in the intercellular diffusion of calcium signals and the tripartite synapses of neurons and astrocytes are more in the gray matter; in most cases, the astrocyte membrane completely covers the pre-synaptic and postsynaptic ends. Similar to neurons, astrocytes also exhibit cellular memory and connect and integrate with neurons both homocellularly and heterocellularly. New circuits are formed far from the damaged site with the degeneration of brain tissues, the brain adaptation process and replacement of astrocytes and long-term memory is preserved with the cooperation of astrocytes close to the lesion site. Cognitive decline is evident in aging and research shows that there is no obvious neuronal death while the death of astrocytes is evident in aging. The volume of astroglia cells decreases in schizophrenia, which is accompanied by impaired limen and cognition and radiotherapy of glioma causes disorders and reduces cognition and memory. In Alzheimer's, the hippocampus is destroyed together with thinning the site of contact with the anterior cortex of the forehead (brain scans).