Fig. 9. Responses evoked by tactile stimulation of the lateral edge of the abdomen in 61-week-old tethered cockroaches under intact and decapitated conditions and young intact animals. Young intact animals readily show escape behavior when stimulated (data from Schaefer and Ritzmann, 2001). By contrast, intact 61-week-old cockroaches did not escape when stimulated. Following decapitation, however, forward directional escape responses (Schaefer et al., 1994) were easily elicited in aged individuals.