> I admit my feeling is that neurons/synapses probably have less than 100 bytes of memory, and also that a byte or less is more plausible, but I would like to see some more rigorous proof that they can't possibly have more than a gigabyte of memory that the synapse/neuron can access at the speed of computation.

Based on lots of reading about brain research and the relentless flow of new and unknown things that need further research, my personal gut feel is that the estimates in that paper about brain computational ability don't really have a valid foundation. There are too many things discovered since then and too many things still not understood.

Some interesting items:

1-Astrocytes are computational cells which need to be included in the math. They have internal calcium waves localized in their processes as well as across the entire cell and inter cell.

2-Recent research showed neuron signal timing down to the millisecond level carries information.

3-Individual cells (neurons and non-neurons) learn, they don't require a synapse and external cell for that capability

4-Neurons are influenced by the electromagnetic field around them and somehow that influence would need to be included in a calc on information flow