Ample evidence shows that recovery from surgery is improved in mice housed in groups.47 Social isolation following stroke increases infarct volumes and decreases brain-derived neurotrophic factor (BDNF) levels in mice48 and alters the neuroinflammatory response to stroke.49 The protective effects of social housing after stroke do not appear to be mediated by passive transfer of body heat but physical contact does appear to be necessary.49 Concern that cage mates will remove sutures from each other’s surgical wound is rarely a significant issue, provided wounds are closed competently. The gene discussed is BDNF; the disease is stroke disorder.