How many brain cells are there?
Around 86 billion.
There are roughly about 86 billion brain cells, or neurons, in a human brain. This is according to a 2009 study published in the Journal of Comparative Neurology. Of these, around 16.3 billion are said to exist in the cerebral cortex and about 69 billion are in the cerebellum. The number of brain cells differ from species to species.