A pilot trial that involved injecting glial cell line derived neurotrophic factor (GDNF) into the brains of people with Parkinson's disease in an attempt to promote dopamine production resulted in clinical improvement, but a second study was stopped early partly over safety concerns. However, one of the original trial's patients, who subsequently died from a heart attack, was found on postmortem examination to have sprouted new dopamine-containing nerve fibres back in the putamen, the part of the brain that loses dopamine in Parkinson's disease—thus confirming neuropathological changes in association with the patient's clinical improvement (Nature Medicine 2005;11: 703-4).

Another brainy question is revealed in Neurology (2005;64: 2004-5). Do we have brain to spare? Humans hold about 1.5 litres of brain tissue, containing roughly 20 billion neocortical neurones with an average of 7000 synaptic connections each. Magnetic resonance studies help to elucidate how closely cognitive loss parallels the loss of brain tissue. They show that minimal cognitive decline can be detected with minor loss of brain tissue, with the redundancy and plasticity of brain tissue providing a buffer against greater impairment.

Minerva is unsurprised by the findings of an inquiry into the effects of music on preoperative sedation and the hypnotic effects …