The effect of bilateral ventral noradrenaline bundle lesions on lever pressing for food in rats.

Food reward has been associated with activation of noradrenergic mechanisms in the brain. Using rats trained to press a lever for food reward, we have investigated the effects of 6-hydroxydopamine lesions, which severly depleted hypothalamic noradrenaline, on the willingness of the rats to press the lever for food reward. We found that performance in the food-rewarded task was significantly impaired following such lesions, and that this was especially marked when the task was made more difficult. From our results we suggest that ventral noradrenaline bundle lesions can decrease the rewarding nature of food, thus making the animals less willing to work for food reward.