Moreover, lesions in the thalamus or cortex, or disruptions of their normal functioning through various techniques, can disrupt the contents of consciousness (Bogen, 1995, 1997).
Nevertheless, not all patterns of neural activity in the thalamus or cortex relate to, or are necessary for consciousness.
We emphasize this distinction to make the point that our overarching task here is to account in biological terms for primary consciousness.
At the same time, such an account necessarily depends on investigation of human subjects, with their ability verbally to report, as the richest source of relevant data.
This relationship allows for a strictly biological account of phenomenal experience and subjectivity that is consistent with mounting experimental evidence.
We examine the constraints on causal analyses of consciousness and suggest that there is now sufficient evidence to consider the design and construction of a conscious artifact.
Consciousness is necessarily subjective and internal (Metzinger, 2003), but its contents can often be inferred from animal behavior or verbal report.
In humans the contents of consciousness are substantially under autonomous regulation, i.e., we decide where to direct our sensory attention or thought processes (Knudsen, 2007).
At the outset, it is important to distinguish primary sensorimotor consciousness from higher-order consciousness (Edelman, 1992, 2003).
Primary consciousness occurs in animals lacking any linguistic capabilities, and is an essential process even in humans.