I'm not very up to date on neurobiology, and so when I saw your comment that we had not found the specific circuits for some experience I was surprised by the implication that we had found that there are neural circuits at all. To my knowledge, all we've got is fMRI captures showing changes in blood flow which we assume to be correlated in some way with synaptic activity. I wondered if you were using 'circuit' literally, or if your intended reference to the oft used brain-computer metaphor. I'm quite interested to know how appropriate that metaphor is.