Man missing 90% of brain poses challenges to theory of consciousness.

http://www.sciencedirect.com/science/article/pii/S0531513103010677

http://www.scholarpedia.org/article/Models_of_consciousness#Thalamocortical_rhythms

http://www.scholarpedia.org/article/Thalamocortical_oscillations

Intracellular studies on anesthetized and non-anesthetized cats have shown that the hyperpolarizing (DOWN) phase of the slow oscillation is associated with disfacilitation, a temporal absence of synaptic activity in all cortical and thalamic neurons (Timofeev et al. 1996; Timofeev et al. 2001a). Even a moderate spontaneous hyperpolarization of thalamic relay neurons during depth-positive EEG waves is sufficient to displace them from firing threshold, thereby affecting transmission of information toward the cerebral cortex (Timofeev et al. 1996). Responses to peripheral sensory stimuli still may reach the cerebral cortex during sleep or anesthesia, but the precision of cortical network to respond to peripheral volley during hyperpolarized (DOWN) periods is lost. The spike timing is critical in cortical information processing and therefore a minimal time interval of stable relay cells activity is required to achieve conscious perceptions (Libet et al. 1967). Thus, the conscious perception is impaired during sleep and anesthesia, likely, because the lost of precision in the sensory information transfer from periphery to the cerebral cortex.

Libet B, Alberts WW, Wright EW, Jr. and Feinstein B (1967) Responses of human somatosensory cortex to stimuli below threshold for conscious sensation. Science 158: 1597-1600.

Desmedt JE, Tomberg C (1994) Transient phase-locking of 40 Hz electrical oscillations in prefrontal and parietal human cortex reflects the process of conscious somatic perception. Neurosci Lett 168:126-129.

Also, a good summary too: http://willcov.com/bio-consciousness/front/Thalamocortical%20system.htm

In general, you need some thalamocortical reentrant loops for consciousness. It is necessary... but we don't know whether it is sufficient.

/r/philosophy Thread Parent Link - qz.com