Dopamine lowers thresholds to firing in emotional, cognitive and motor
areas of the brain. In the difference between busy and 'too busy'
dopaminergic activity, lies the commonly noted relation between creativity
and 'its unhealthy extremes', ie madness. In general, "mental madness" (eg
symptoms of disordered cognition covered by the sloppy umbrella label
"Schizophrenia") involve actentions with spasmodically manic
"motor-behavioural" activities and/or a lot of mental activity. When the
thresholds-lowering function of Dopamine in the 'motor division' of the
brain is deficient it shows up as symptoms of 'Parkinson's disease', with
symptoms such as a greater or lesser difficulty to 'get going' with certain
Behaviour. Whilst, in cases of damaged and depleted dopaminergic neural
tissues and pathways, symptoms of Parkinson's disease "is the 'motor side'"
of too little dopaminergic activity, the 'mental side' of Dopamine-shortage
is presumably making the mind less flexible and creative than normal. This
effect may however be too subtle and not ostentatious enough to bee easily
recognised and investigated.