C-fiber stimulation

McGowan SE. 2007. Vitamin A deficiency increases airway resistance following C-fiber stimulation. Respir Physiol Neurobiol 157 281-289. 

Histologic evidence shows a close anatomic correspondence between mast cells and G-fibers in peripheral organs (Skofitsch et al., 1985 Stead et al., 1987) and in the nodose ganglia (Undem and Weinrich, 1993). There is both functional and structural evidence for innervation of mast cells by C-fibers. Stimulation of the trigeminal nerve causes mast cells in the rat dura mater to degranu-late. This effect, which is apparent on histologic evaluation, is abolished by treatment with neonatal capsaicin and this may be mediated by C-fibers (Dimitriadou etal., 1991). 

Bombesin and gastrin-releasing peptides have been shown to sensitize C-fiber neurons to subsequent activation by capsaicin and ATP. In addition, these peptides enhance the pulmonary chemoreflex induced by C-fiber stimulants. The relevance of these observations may be heightened in small-cell lung cancers, as the cancer cells are known to secrete various peptides, including bombesin-like peptides (Gu and Lee 2005). 

I have modified the formulation in Pfi sicalRealization to allow microphysicaJ realizers of instances of property realizers of a property to count as microphysical realizers of instances of that property -for example, to allow a microphysical realizer of C-fiber stimulation to count as a microphysical realizer of pain. This is required by things I say later. I speak of the state-of-afFair causal profiles as isomorphic with the property causal profiles, rather than identical with them, because slightly different sorts of causal features are involved in the two cases - in the one case features of states of affairs, in the other features of properties. 

It is not immediately obvious how to apply this to the case of an instance of pain and an instance of C-fiber stimulation, where pain is property-realized by C-fiber stimulation. The states of affairs that make up the core of the realizer of the pain instance should include ones that contribute directly to implementing the causal profile of pain but should not include, for example, ones that contribute to the activation of an accurate C-fiber stimulation detector. But of course the case at hand is one in which it is through the instantiation of C-fiber stimulation that the causal profile... 

Suppose there could be prosthetic C-fibers, perhaps made of silicon, and that the stimulation of these can realize pain in essentially the same way, whatever that is, that the stimulation of C-fibers can. Stimulation of these would not activate an accurate natural C-fiber-stimulation detector, though it would activate some other sort of device. We can suppose that in a case where pain is realized in natural C-fiber stimulation and in a case where pain is realized in prosthetic C-fiber stimulation, the cores of the pain instance realizers are states of affairs of the same sort. The properties involved in these states of affairs are functional ones shared by natural C fibers and prosthetic ones. This is not, of course, to say that the cores of all pain instance realizers are states of affairs of the same sort. If, as David Lewis imagined, Martian pain is realized in the inflation of tiny cavities in the feet, the cores of Martian pain instance realizers will be very different from the cores of human pain instance realizers. But it is compatible with this that in any particular case of pain instantiation, the instance of pain has a realizer whose core is different from, though part of, the core of the realizer of the instance of the physical property that is the property realizer of the pain. In our case, the core of the realizer of the pain instance is different from, though part of, the core of the realizer of the C-fiber-stimulation instance. 

An advantage of this account is that it holds instances of mental properties to be physically realized in a way that allows them to be causally efficacious, and it removes the threat that their causal efficacy is preempted by the instantiation of their physical property realizers. In the case where pain is property-realized by C-fiber stimulation, it is not true to say that the causal work we would like to ascribe to the pain instance is really done insteadhy the C-fiber-stimulation instance. Nor is it true, as it is on Kim s instance-identity thesis, that, although this work is done by the pain instance, this is only because it is identical with the C-fiber-stimulation instance. The work is indeed done by the C-fiber-stimulation instance, but this is because the core of the C-fiber-stimulation instance realizer has the core of the pain instance realizer as a part. It is only because the C-fiber-stimulation instance realizer contains the pain instance realizer that it has the relevant effects. Recall that the core of a property instance realizer consists of the states of affairs that contribute directly to the implementation of the causal profile of the property. The core of the C-fiber-stimulation instance realizer contains states of affairs that contribute to the implementation of the causal profile of pain, but these make this contribution only because they realize states of affairs contained in the state of affairs that is the core of the pain instance realizer. 

It is, of course, not properties of this sort that philosophers usually have in mind when they speak of the first-order properties of persons that realize their mental properties. Having C-fiber stimulation occurring in one is not an MSE-property it is rather a property that is realized by different MSE-properties on different occasions. In all likelihood, the MSE-properties are... 

The first argument is based on the observation that for some explanations, which are not paradigmatically mechanistic, this idea makes perfect sense. Assume that the freezing of water is nothing but the lattice-structure formation of sums of H2O molecules. Now, how does water freeze It does so by the formation of lattice structures of H2O molecules. Assume that pain is identical to C-fiber stimulation. How do pains occur They do by the occurrence of C-fiber stimulations. This matches one of the more intuitive examples for reductive explanation. Nagel suggests that when ... 

If functional terms gain their meaning by the theory they are used in, the property structure they reveal will (at least partly) be given via a definition building on the Ramsey sentence of the theory the term occurs in (if you are not familiar with the notion, please read the first few paragraphs in Sect. 6.7). Thus, to appropriately model the property structures of the terms in pain reduces to C-fiber stimulation , we should not model the property structure revealed by pain as being pain. Assume that pain is exhaustively described by being the internal state that maps tissue... 

We could introduce the additional condition that the property structures involved here should be property structures that mimic the structure of multiple realization, reflecting, for example, the intuition that every mental token (that is one object presented as an instance of mental kind M) reduces to a physical token (that is the same object presented as instantiating a physical kind, where this kind is one of the realizers of M). This nicely fits the idea that the realization relation is an explanatory relation to give an example, on this view, a pain token is a pain token in virtue of being a token of C-fiber stimulation. 

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