Effects of local injection of CRF antagonist on LC response to CeN stimulation. A, PSTHs and rasters constructed around CeN stimulation (Ce stim) (500 μA trains; horizontal bar) for an LC unit showing a monophasic response (top). This response is completely blocked by the CRF antagonist (bottom; nonparametric Newman–Keuls analog test; p < 0.05). B, Same representation for another single unit showing a biphasic response to CeN stimulation. Before αhCRF injection (top), the cell exhibits a biphasic response with an early (shaded area) and a late phase. After the injection (bottom), the early response is greatly attenuated (30% of its preinjection value; nonparametric Newman–Keuls analog test; p < 0.05), whereas the late phase is spared.