[peter303]

The physical human brain has 86 billion neurons with up to 10,000 connections each. However they are somewhat structured (e.g. the seven layers of the cerebral cortex segregated into vertical silos a few hundred cells wide) reducing the arbitrariness of connections. So say the connectome has 100 trillion parameters.

The brain also has a bunch of other cells that dont appear to encode information. They may supply structural scaffolding and chemicals to mediate neuron function.