> But of course, every neuron in the brain is bafflingly complex and we still don't know or understand how that complexity manifests itself in thought and intelligence.

Indeed.

Biophysics of Computation: Information Processing in Single Neurons challenges this notion, using richly detailed experimental and theoretical findings from cellular biophysics to explain the repertoire of computational functions available to single neurons. The author shows how individual nerve cells can multiply, integrate, or delay synaptic inputs and how information can be encoded in the voltage across the membrane, in the intracellular calcium concentration, or in the timing of individual spikes: https://www.amazon.com/Biophysics-Computation-Information-Co...

If you like this, there is a book about the complexity of a single neuron of the brain "Information Processing in Single Neurons" [1].

[1] https://www.amazon.com/Biophysics-Computation-Information-Co...

Only an observer of the topic but I think it is good to review Koch's book about the real complexity of a single neuron [1].

[1] https://www.amazon.com/Biophysics-Computation-Information-Co...