Abstract :
In the struggle about the role of monism and dualism as basic concepts of the mind-brain relation, the indeterminacy of quantum events has led an increasing number of authors to postulate quantum brain dynamics as the key towards a scientific understanding of consciousness. In most cases some specific form of macroscopic quantum states in the brain are invoked without giving details for their occurrence or persistence. This raises immediately the question, how such states could survive thermal fluctuations in the hot and wet brain environment. In this paper we present a model for a quantum mechanical trigger which regulates synaptic exocytosis, the regulator for ordered brain activity. The model is based on a quantum mechanical tunnelling process which is stable against thermal fluctuations and consistent with the physiological conditions of the synaptic membrane.
