> * 86 billion neurons in a brain [1]*

> * 400 transistors to simulate a synapse [2]*

> * That's 34 trillion, 400 billion transistors to simulate a human brain.*

You forgot about:

1-Astrocytes - more common than neurons, computational, have their own style of internal and external signaling, have bi-directional communication with neurons at the synapse (and are thought to control the neurons)

2-Synapse: a single synapse can be both excitatory and inhibitory depending on it's structure and the permeant ions inside and outside the cell at that point in time and space - are your 400 transistors handling all of that dynamic capability?

3-Brain waves: are now shown to be causal (influencing neuron behavior) not just a by-product of activity. Many different types of waves (different frequencies) that operate very locally (high freq), or broadly (low freq). Information is encoded in frequency, phase, space and time.

This is the summary, the details are even more interesting and complex. Some of the details are probably not adding computational capabilities, but many clearly are.