CONSCIOUSNESS ABSTRACT (Bogen's approach)

Explaining consciousness physiologically begins by recognizing that the meanings of "consciousness" have in common (as their intersection, see figure) a crucial core here called C, also called subjectivity, awareness, consciousness-as-such, or consciousness per se. A sharp distinction is made between the property C and the contents of consciousness, partial loss of which is typical of cerebro-cortical lesions. The neuronal mechanism producing C also acts as an attention-action coordinator, hence must have widespread connectivity. These requirements are best met by the thalamic intralaminar nuclei (ILN). Although large lesions elsewhere leave C undisturbed, quite small bilateral lesions in ILN engender immediate unresponsiveness. This combination of anatomic and neurologic evidence is bolstered by a variety of physiologic evidence leading to the ocnclusion that further study of the ILN, and their interactions with lower centers as well as cerebral cortex, are most apt to yield a better understanding of consciousness.