I guess it is only a matter of time before PET scans and functional NMR have the required resolving power to define the structure of neuronal groups. There are probably similarities here to how genes were understood in increasing detail as new genetic methods were developed during this century.
The issue of GAP JUNCTION coupling of cells in the brain is interesting. I guess evolution has probably made use of every available trick for cell-cell communication in the brain. I view this as a fundamental Edelmanistic principle: nature has maximized the variability of mechanisms in the brain in order to maximize the chance for "tuning" brain activity to a diverse and variable environment.
The issue of non-overlapping and overlapping functional units in the brain seems to never go away. Many people have often fallen back on the hunch that there is some type of holograph-like functionality in the brain by which distributed activity is coordinated into meaningful wholes. I agree that when we start looking for things like "Winner Take All" processes in the brain, we have to get specific about the network architectures involved. I can never shake some of Dug Hofstadter's descriptive phrases, for example, "tangled hierarchies". It is very natural for us to make integrated circuit-like models for something like a WTA network, but in a real brain I suspect that the interesting networks will be very tangled indeed.
"We should look for selection. If there is no selection Edelmanism is not much better than Calvinism." The parallels between Darwinism and Edelmanism are amusing. To this day people still argue that natural selection can not account for the diversity of life. I have never been willing to follow Edelman's leap of faith and assume that "neuronal group selection" is the best way to think about how the brain works. Edelman's black/white division between brain selectionism and brain instructionism makes me nervous. This sounds like an artificial division much like the wave/particle duality that physicists have long chased around. I guess I am a pragmatist. If it advances neuroscience to think about brain function in terms of selection on Monday, Wednesday, and Friday but to use instructionalistic thinking the rest of the week, so be it. I doubt if the brain itself cares any more than the universe concerns itself with the question, "Is an electron a particle of a wave?"
When a chicken is raised only seeing vertical lines and has a visual cortex full of vertically oriented feature detectors, is that due to selection or instruction? I find it hard to split this hair. Just show me the cellular and molecular mechanisms involved, define for me the network architecture that is required to allow the visual cortex to tune itself in this way to environmental stimuli, let me build a model in a computer that is based on these biological details and that replicates the global function and I will be satisfied, and then I will decide if I want to call the process selection or instruction or something else.
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