We use the tools that we have, and right now that means genetic specificity with calcium imaging and channelrhodopsin. In other words: how do groups of identified neurons operate? In even fewer words: microcircuits.
I am probably reading too much into things, but it seems like microcircuits are the new hotness. Every week, there’s a new paper using the word (soon to solidify its buzzword status). I looked up the publications that used the term and found something interesting. Compare the number of publications I found through google scholar* (above) – which indexes a very broad and interdisciplinary mix of journals – and pubmed (below) – which indexes mostly biomedical journals:
The number of publications in google scholar is fairly steady until 1999 when it starts steadily increasing. There’s very little action in pubmed until 2002 when it starts rocketing off. What’s happening? Many of the papers on google scholar have a computational or physics-y bent, appearing in such exciting places as the ‘ International Journal of Man-Machine Studies’. For years, these poor computational fools labored away not to be noticed until the experimental tools caught up to the theory: hence the sudden interest.
The very first reference that I can find is A reinterpretation of the mathematical biophysics of the central nervous system in the light of neurophysiological findings by N. Rashevksy in 1945. Yes, that Rashevsky. Unfortunately, I can’t seem to get access to the paper itself. Same goes for the next paper in 1957 from D. Stanley-Jones (Reverberating circuits). And then it took off from there…
In a different tradition, we can trace this fine term to Eric Kandel who appears to have coined its neuroscience term in this 1978 paper where they “reduced this isolated reflex to a microcircuit (consisting of a single sensory cell and single motor cell) so as to causally relate the contribution of individual cells to the expression and plastic properties of the behavior.” Nary a peep was heard from microcircuitry until 1991 when Douglas and Martin mapped a “function microcircuit for visual cortex”.
(What is the equivalent of Mainen and Sejnowski in microcircuits? Someone has to write that crisp paper so that they, too, can get ALL the citations.)
* technically, I searched for ‘microcircuits neural’