"Bad Memories Written With Lasers" (BBC News) describes a technique wherein memories are written into fly brains with lasers. An article in the most recent Wired, "Powered By Photons" (not online yet) describes what I presume is some of the background to this sort of manipulation. Genes from an algae are introduced into the brain via viral vector, in anatomically selective regions, with selective uptake by various kinds of neurons. This allows fine targeting of the neurons that will take up the gene. The gene produces proteins that open channels in cells walls when photons hit them; another variety of such a gene-protein, responsive to a different light wavelength, closes channels. The upshot is neural firings can be controlled by light. (This area of exploration now has its own name: optogenetics.)
The Wired articles describes a mouse manipulated such that the scientists can control it, making it run counterclockwise, or stop doing so, using light controls. Techniques like these are being explored for helping with movement problems in Parkinsons.
These items remind me of the cyborg beetle described in Technology Review, which uses an electrical rather than light based technology.
Putting aside the usual sort of reductive directions that hover on the border of such reports (true, this helps us learn about basic mechanisms of memory in the fly; how much this will tell us about the complex phenomenon of memory as interacting with other aspects of perception and action in more complex creatures, or even the fly, remains to be seen), this raises some interesting questions.
For example, in what sense is an animal that has its locus of control in something outside it animal, in the sense of: moving itself animately?
But let's not think the answer would be easy, because, hey, come to think of it, it's not as if the locus of control in us is in us purely: the light out there in the world lulls and sways us via our eyes and ecological attunement to the surround. If you loom a shadow at me, or at an infant, I will duck away. What's the difference between environmental light shining on the retina producing a change in behaviour, and light shining directly on/in the brain, producing behaviour? Remember here that the eyes can be considered a prolongation of the brain. Also remember that the genes taken from the algae are ones that make algae light sensitive and thus able to respond to light. In evolution, features such as these evolve into light sensitive spots on outer membranes, and that's the beginning of the sort of evolutionary account that we reconstruct for eyes.
One difference is activity: there is a way in which we are active, in a whole body way, in setting up the sort of attunements in virtue of which the ambient optical array is ecologically salient. This is not the case if a machine control system is producing behaviours in an organism. But what about the Parkinson's case, should it work? Perhaps we could imagine someone pushing a button that helps get them moving, by shining a light that produces firings in part of their brain. But then they're controlling the machine that controls them. They are not mere patients of outside interventions. We should remember here that when people who are conscious and are undergoing neurosurgery have memories or perceptions stimulated in them by the neurosurgeon, they experience the memory or perception (I smelt an apple!) but experience it as strange (but it was weird, not like smelling a real apple!). Presumably this has something to do with the fact that they are mere patients of such sensations, not agents of them.
Questions of activity and passivity arise at this juncture--ones that Merleau-Ponty was thinking about in his later work.