Losing the ability to start things, or to keep going when they get harder, is one of the most disabling features of depression, ADHD and addiction. It is also one of the least understood.
Researchers at Nagoya University report that a small population of neurons in the hypothalamus tracks both how much reward an animal expects and how much effort it will take to get it. When they suppressed those cells in rats, the animals worked less hard and gave up sooner.
