Scientists: Consciousness in Quantum State After Death, page-4

Pure speculation at this stage....there being no examples of non brain related conscious activity, the senses inputting information to the brain to process and represent some of this information in conscious form. There is no such activity on quantum scale, but obviously quantum particles make up the brain....including everything else.

I think the smallest functional structures discovered in brain architecture are quantum micro-tubules, of course these alone do not produce consciousness. That requires the numerous functions of the system as a whole, and if any part breaks down, conscious mind is diminished in relation to the damage done.