Energetics and neuron death: hibernating bears or starving refugees?

The argument is made that the evidence for "use it or lose it" in neuronal loss during aging is rather weak. The first half of the commentary focuses on the distinctly "wear and tear" flavor to the mechanism of action of excitotoxins, and the broad range of cases of neuron loss in which they play a role. The second half challenges the "use it or lose it" interpretation of the phenomenon of glucocorticoid-induced neuron death.