By now you may have concluded that the conversation was neitherabout Descartes nor about philosophy, although it certainly wasabout mind, brain, and body. My friend suggested it should takeplace under the Sign of Descartes, since there was no way of approachingsuch themes without evoking the emblematic figure whoshaped the most commonly held account of their relationship. Atthis point I realized that, in a curious way, the book would be aboutDescartes' Error. You will, of course, want to know what the Errorwas, but for the moment I am sworn to secrecy. I promise, though,that it will be revealed.
As a consequence of natural analgesic actions or as a result of the administration of drugs that interfere with body signaling (painkillers, anesthetics), the brain receives a distorted view of what the body state really is at the moment. We know that in situations of fear in which the brain chooses the running option rather than freezing, the brain stem disengages the part of the pain-transmission circuitry, a bit like pulling the plug. The periqueductal gray, which controls these responses, can also command the secretion of natural opioids and achieve precisely what taking an analgesic would achieve -- elimination of pain signals.In the strict sense, we are dealing here with a hallucination of the body because what the brain registers in its maps and the conscious mind feels do not correspond to the reality that might be perceived. Whenever we ingest molecules the have the power to modify the transmission or mapping of body signals, we play on this mechanism. Alcohol does it; so do analgesics and anesthetics, as well as countless drugs of abuse. It is patently clear that, other than out of curiousity, humans are drawn to such molecules because of their desire to generate feelings of well-being, feelings in which pain signals are obliterated and pleasure signals induced.
The neural basis for the self, as I see it, resides with the continuous reactivation of at least two sets of representations. One set concerns representations of key events in an individual's autobiography, on the basis of which a notion of identity can be reconstructed repeatedly, by partial activation in topologically organized sensory maps. ... In brief, the endless reactivation of updated images about our identity (a combination of memories of the past and of the planned future) constitutes a sizable part of the state of self as I understand it.The second set of representations underlying the neural self consists of the primordial representations of an individual's body ... Of necessity, this encompasses background body states and emotional states. The collective representation of the body constitute the basis for a "concept" of self, much as a collection of representations of shape, size, color, texture, and taste can constitute the basis for the concept of orange.