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Objective: In normal subjects, motor evoked potentials (MEPs) produced by transcranial magnetic stimulation (TMS) from the motor cortex are increased after non-fatiguing exercise of hand muscles. This phenomenon is called post-exercise facilitation. This study aims to test the hypothesis that psychiatric syndromes (major depressive episode, schizophrenia) have different levels of post-exercise facilitation compared to controls. Methods: Patients with DSM-IV major depressive episode (six female, four male), schizophrenia (two female, nine male) and a control group (nine female, four male) participated. MEPs were elicited pre- and post-exercise from the contralateral abductor pollicis brevis by TMS over the primary motor cortex. Results: Post-exercise facilitation expressed as a percentage of baseline was 510% in controls, 110% in depression and 190% in schizophrenia. There were significant differences in patients with depression and schizophrenia compared to controls (p = 0.0001, p = 0.0008). Conclusions: Post-exercise facilitation was reduced in depression and schizophrenia, suggesting impaired cortical excitability in these disorders. Further studies may discriminate between the two groups. [ABSTRACT FROM AUTHOR]

The article reviews books including "The Gulf Stream," by B. Voituriez, "Conservation: Linking Ecology, Economics, and Culture," by Monique Borgerhoff Mulder and Peter Coppolillo.