Fig. 4. Scatterplots of -aminobutyric acid (GABA)- and Mas-allatotropin-dependent phase shifts at different times in the circadian cycle. (A) GABA injections (15±6 pmol in 1.5±0.6 nl of saline with blue food dye, mean ± S.D.; N=35) cause maximal phase delays during the early subjective night (-4.2 h at CT14:50 h) and maximal phase advances during the middle of the subjective night (3.05 h at CT16:50h). (B) Irrespective of the time of day, control injections (0.5-2 nl of saline with blue food dye; N=43) caused only small statistically non-significant phase delays and phase advances. (C) Injections of Mas-allatotropin (150±60 fmol in 1.5±0.6 nl of saline with blue food dye, mean ± S.D., N=36) cause maximal phase delays during the early subjective night (-4.9 h at CT14:05 h) and maximal phase advances during the middle of the subjective night (3.2 h at CT17:09 h). Each point represents the phase shift (in circadian hours) resulting from a single injection. Phase advances are shown as positive values and phase delays as negative values.