Fig. 4. Mean number of T-cell action potentials for each echolocation sequence and mean of the five greatest instantaneous spike rates per intensity for Neoconocephalus ensiger and Amblycorypha oblongifolia. Black lines: Myotis septentrionalis gleaning attack echolocation sequence; grey lines: M. septentrionalis search call sequence. Bars indicate ± s.e.m. B, background activity (see Materials and methods). Different letters indicate significant differences between activity levels.