Minimal neuroanatomy for a conscious brain: Homing in on the networks constituting consciousness

There is a consensus that consciousness is constituted by only a Subset of all neuroanatomical regions and processes, but no agreement exists regarding which particular subset(s) constitutes it. We propose that a consensus will be reached if investigators (a) pool their knowledge regarding the regions whose non-participation does not in principle render the nervous system devoid of consciousness (e.g., the cerebellum, amygdalae, hippocampi, hemispheric commissures, 'pre-cortical' thalamus, and vast regions of the cortex), and (b) focus on the long-overlooked olfactory system. This 'brutally reductionistic' approach may isolate the physical basis of consciousness; even its falsification would help to illuminate this enigma. (C) 2009 Elsevier Ltd. All rights reserved.