INS and obesity due to melanocortin 4 receptor deficiency: The results of the combined chronic experiments, in which insulin was either elevated by IND or DIO, demonstrate that the firing of these neurons in the olfactory bulb is highly state dependent; long-term exposure to the hormone insulin or a state of obesity can perturb modulation of intrinsic excitability, which in turn can change the relay of sensory information encoded by firing patterns.