FOS and Hypoglycemia: In our study, a smaller proportion of activated C1 neurons in KD-fed rats may indicate a delayed response to hypoglycemia due to the time-course of Fos expression, which is reported to peak at 2 h post stimulus in the medulla [42]; however, in the absence of a longer time-course (e.g., 3 h post insulin), lower (but not delayed) activation of C1 neurons cannot be excluded.