Future developments

Neuronal signalling cannot always be reduced to classical synaptic transmission resulting in a binary inhibition or excitation. Many types of molecules that are bioactive do not fit readily into the profile of a classical neurotransmitter. Release of bioactive substances can occur beyond the familiar axonal synapse. The actions of bioactive substances, including classical transmitters, can be modulatory, global and long term. It is erroneous to extrapolate from events at the level of the neuron or gene to wholescale functions and dysfunctions. The actions of bioactive substances have to be appreciated within the context of neuronal populations, and in turn within the holistic anatomical context of the brain. Molecular biology will contribute to this more precise understanding of the relationship between individual genes, gene mutations, molecular and cellular phenotypes, and corresponding functions and dysfunctions.