The human brain is often quoted to contain 100 billion neurons, with many times more supporting glial cells, although the origin of this estimate is unclear.3 While various attempts have been made to estimate the numbers (and have suggested values ranging from 85 to 120 billion neurons in the human brain), experimental evidence indicates that approximately 86 billion neurons can be found in the human brain.3,4 The neurons of the nervous system can be subdivided on the basis of their morphology, as detailed on the slide.1
References:
1. Nerve cells, neural circuitry, and behavior. In: Kandel ER, Koester JD, Mack SH, Siegelbaum SA (eds). Principles of Neural Science. 6th edition. McGraw-Hill, 2021.
2.Yao Z, van Velthoven CTJ, Kunst M, et al. A high-resolution transcriptomic and spatial atlas of cell types in the whole mouse brain. Nature 2023; 624 (7991): 317–332.
3. Herculano-Houzel S. The human brain in numbers: a linearly scaled-up primate brain. Front Hum Neurosci 2009; 3: 31.
4. Azevedo FA, Carvalho LR, Grinberg LT, et al. Equal numbers of neuronal and nonneuronal cells make the human brain an isometrically scaled-up primate brain. J Comp Neurol 2009; 513 (5): 532–541.