Microglia is one of the major resident immune cells in the central nervous system and is considered to be the key cellular mediator of neuroinflammatory processes. Identification of different Microglial states of activation by morphologic means has been one of the major challenges in the field of neurobiology of diseases. Therefore, microglial biology demands techniques to identify differing stages of microglia in different neuroanatomic locations as well as understanding the role of Microglia in different Neurological diseases. This present study is aimed towards summarizing the literature and for understanding the progress made in different Cytomorphological and Cytochemical techniques of identifying Microglia. This study also review recently used Immunohistochemistry techniques, along with Ultrastructural studies determining different morphological features of resting to activated phagocytic Microglia in a viral induced experimental animal model of neuroinflammation. Results revealed that chronic Microglial activation is considered to be an important component of neuronal dysfunction, injury, and loss (and hence to disease progression). Thus, Microglial research with special emphasis on identification of different activation states of Microglia has gradually become significant. 1. Introduction Microglia, the resident macrophages of the Central Nervous System (CNS), is known to support and sustain proper Neuronal functions. Existence of this Glial cell in CNS has been reported, a century ago [1]. Nissl was the first to recognize Microglia and name it as “stabchenzellen” (rod cells) and considered it as a reactive neuroglia. He also suggested that, Microglia has the capacity of migration and Phagocytosis [1]. Regarding the origin of Microglia, a complete framework was provided for defining this particular cell type by del Rio-Hortega in 1932, but still many of the features remained controversial [2]. Microglia transits through different stages of development to attain its maturity and functionality in the CNS. The first stage is of Ameboid Microglia, and it shares common Immunological, Histochemical and Morphological features with Macrophages outside the CNS [2]. Hence, it is also sometimes termed as the Macrophages of the Brain. The Ameboid microglia is considered to be round in shape or have short and broad processes. It is assumed that cells with Dendrite and elongated morphology also belong to this particular type of Microglia (Ameboid) [3]. In due course of time and under certain circumstances, some parts of the Embryonic Ameboid Microglia gets
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