On the Role of the Microtubules in Cognitive Brain Functions

In this article we review the role microtubules (MTs) have been conjectured to play as a substrate for information processing and signaling mechanisms in the brain at a sub-cellular level. We discuss their structure, known biophysical functions and theoretical predictions related to signaling, conduction and transport, all of which may contribute to pre-conscious processing at a molecular level. Major criticisms of microtubule information processing based concepts of cognitive brain function are examined, and the progress in work addressing these issues is also discussed. It is concluded that the question of whether any of these processes operate at a quantum level is still open to debate and speculation.