Thursday, September 21, 2017

Chemical computing

One of the potentially most far reaching and revolutionary ideas in cog-neuro is the suggestion that brain computations are largely intra-neuronal rather than inter-neural. Randy Gallistel has been pushing this idea for the last several years and more and more evidence is pilling up for its feasibility, some of which I have reviewed/mentioned in FoL. Here is another brick in that wall. The authors show how to build "synthetic gene circuits"made up entirely of RNA that form biological "ribocomputing devices." This is a step to "develop biological circuit design strategies that will enable cellular function to be programmed with the same ease hat we program electronic computers." It is obvious to me that should this succeed, it will provide a proof of concept that Gallistel has been on exactly the right track. If correct, it will turn out that brains compute roughly like machines do, and if this happens all the hocus pocus surrounding neural nets and their deep unfathomable properties will, poof, disappear. Recalled as just another wrong turn in the history of science. Personally, I cannot wait.


  1. Several points:

    I suppose it depends on what you mean by "computations," but I'm aware of no solid evidence for Gallistel's view. In reality, at least for people familiar with the nuts and bolts of neuroscience, "intra-neuronal" vs. "inter-neuronal" is a false dichotomy: Both are involved. Even the most basic view of neuronal signaling--the sort of thing taught in intro neuro classes--involves both intra- and inter-neuronal elements (for instance, the presynaptic neuron releases neurotransmitter into the synapse; the postsynaptic neuron picks it up; the signal is conveyed from outside to inside via G-protein-coupled receptors, for instance). It's the same for receptor up- and down-regulation, pharmacological effects including drug tolerance, neuronal "self-regulation" through autoreceptors, long-term potentiation, etc. It's not an either-or sort of thing.

    The fact that RNA *can*, in principle, be used to do logic gates doesn't mean that it *is* so used, at least not in the way that Gallistel presumably imagines. (After all, the stuff they're building is de novo.) Even if it does, it doesn't mean it's the *only* location or method of computation.

    1. Very much agree - "neural codes" seem to exist at numerous levels: