Number of synapses in cortex

Value 1.5e+14 unitless
Organism Human Homo sapiens
Reference link
Primary Source Pakkenberg B, Gundersen HJ, Mortensen EL, Lauritzen MJ, Jeune B, Regeur L, West MJ, Schwartz TW. [The normal brain: a new knowledge in different fields] Ugeskr Laeger. 1997 Feb 3 159(6):723-7. AND Pakkenberg B, Pelvig D, Marner L, Bundgaard MJ, Gundersen HJ, Nyengaard JR, Regeur L. Aging and the human neocortex. Exp Gerontol. 2003 Jan-Feb38(1-2):95-9.
Comments (Abstract of 2nd primary source:) "The total number of synapses in the human neocortex is approximately 0.15 x 10^15 (0.15 quadrillion). Although the effect of aging is seen in all estimated structural elements, the effect of sex is actually higher. The functional relevance of these differences in neuron numbers in both age and gender is not known." Many useful brain facts and references at the cited website
Entered by Daniel Ramot
ID 100693