In mice, falling dopamine shifts attention from threat to reward

A mouse smells an odor and braces for an unpleasant puff of air. In a new study from Hokkaido University, researchers found that dopamine activity in the tail of the striatum falls as the threat becomes familiar, helping the animal shift from defensive behavior toward seeking a reward.

The team gave mice three odor cues: one followed by water, one followed by an unpleasant air puff and one followed by nothing. Blinking showed that the mice anticipated the air puff; licking showed that they anticipated water. At first, the threat-linked odor produced a strong defensive response. With repeated exposure, blinking gradually declined, while the mice anticipated the reward earlier.

The researchers tracked dopamine responses during this process. The signal was initially high when the mice encountered the threat, then decreased as they adapted. That pattern suggested dopamine was helping direct attention toward defense when danger was new or important, and that its decline allowed other opportunities to compete more effectively for attention.

The team then used optogenetic tools to prevent the normal decline in dopamine activity. The manipulated mice were slower to adapt to the repeated air puff and did not seek the water reward as effectively. The result supports a causal role for the dopamine decrease, rather than merely linking it to the animals’ changing behavior.

And concretely? The finding offers a clearer picture of how a brain can stop treating a repeated threat as its only priority and return to learning, exploration and reward-seeking. For now, the evidence is limited to mice and to an experimental manipulation; it does not establish a treatment or a human effect. Professor Iku Tsutsui-Kimura led the study, published in Communications Biology.