Self Comes to Mind

The integration of all these diverse and spatially distributed maps takes place by cross-signaling within the same time window. It does not require a single brain site where the diverse components would be remapped. Let us consider each of the protoself contributors individually.
MASTER INTEROCEPTIVE MAPS
    These are the maps and images whose contents are assembled from the interoceptive signals that hail from the internal milieu and the viscera. The interoceptive signals tell the central nervous system about the ongoing state of the organism, which may range from the optimal or the routine to the problematic, when the integrity of an organ or tissue has been violated and damage has occurred in the body. (I am referring here to nociceptive signals, which are the basis of feelings of pain.) Interoceptive signals signify the need for physiological corrections, something that materializes in our minds, for example, like feelings of hunger and thirst. All the signals that convey temperature, along with myriad parameters of the operation of the internal milieu, are covered under this heading. Last, interoceptive signals participate in the making of hedonic states and the corresponding feelings of pleasure.

     
Figure 8.2: The main components of the protoself.
    On any given moment, a subset of these signals, as assembled and modified in certain upper-brain-stem nuclei, generate primordial feelings. The brain stem is not a mere pass-through of the body signals to the cerebral cortex. It is a decision station, capable of sensing changes and responding in predetermined but modulated ways, at that very level. The workings of that decision machinery contribute to the construction of primordial feelings, so that such feelings are more than simple “portrayals” of the body, more elaborate than straightforward maps. Primordial feelings are a by-product of the particular way in which the brain-stem nuclei are organized and of their unbreakable loop with the body. The functional characteristics of the particular neurons involved in the operation possibly contribute as well.

     
Figure 8.3 : The brain-stem nuclei involved in generating the core self. As shown in Figure 4.1 , several brain-stem nuclei work together to ensure homeostasis. But the homeostasis-related nuclei project to other groups of brain-stem nuclei (other brain-stem nuclei , in this figure). These other nuclei are grouped in functional families: the classical nuclei of the reticular formation , such as the nucleus pontis oralis and nucleus cuneiform, which influence the cerebral cortex via the intralaminar nuclei of the thalamus; the monoaminergic nuclei , which directly release molecules such as noradrenalin, serotonin, and dopamine to widespread regions of the cerebral cortex ; and the cholinergic nuclei , which release acetylcholine.
In the hypothesis advanced here, the homeostatic nuclei generate the “feelings of knowing” component of the core self. In turn, the neural activity underlying that process recruits the other, nonhomeostatic brain-stem nuclei, to generate “object saliency.”
Abbreviations are as in Figure 4.1 .
    Primordial feelings precede all other feelings. They refer specifically and uniquely to the living body that is interconnected with its specific brain stem. All feelings of emotion are variations of the ongoing primordial feelings. All feelings caused by the interaction of objects with the organism are variations of the ongoing primordial feelings. Primordial feelings and their emotional variations generate an observant chorus that accompanies all other images going on in the mind.
    The importance of the interoceptive system for the understanding of the conscious mind cannot be emphasized enough. The processes in this system are largely independent of the size of the structures in which they arise, and they constitute a special kind of input that is present from early on in development and throughout childhood and adolescence. In other words, interoception is a suitable source for the relative invariance required to establish some sort of stable scaffolding for what will eventually constitute the self.
    The issue of relative invariance is critical because the self is a singular process and we must identify a plausible biological means to ground that singularity. On the face of it, the organism’s single body should provide that much-needed biological singularity. We live in one body, not in two (not even Siamese twins deny this