Abstract
The temporal characteristics of the neural signalling believed to underlie consciousness are considered in the light of the master-module theory (Cotterill, 1995, 1996, 1997). It is suggested that consciousness is mediated by the flow of signals around what is referred to as the vital triangle, which comprises the sensory-processing areas of the cortex, the master module itself, and the thalamic intralaminar nuclei, these three regions forming a closed loop. The interactions between the apices of this triangle and other brain components are conjectured to provide consciousness with access to memory, and to produce the feelings known as qualia, to which the body's muscles contribute through what could be called internal reafference. It is also argued that consciousness is critically dependent on the carrier wave provided by oscillations in the gamma band, the amplitude modulation of which travels around the vital triangle. These new ideas are illustrated by reference to the cortical machinery involved in speech. The confinement of language processing to a single cerebral hemisphere is considered, and it is suggested that this unilateralization is a consequence of the fact that the muscles involved in articulation serve structures which cross the body's medial plane, and that these muscles therefore cannot be independently activated. An experiment is proposed which would test this explanation, though rather indirectly.
