黑料吃瓜资源

When you pick up a baby, you can鈥檛 help feeling happy. But where does this feeling come from? How does it influence future behavior? 黑料吃瓜资源 (CSHL) Associate Professor Stephen Shea has found that, when it comes to maternal care, social contact is its own reward.

鈥淲e know that, as human beings, it鈥檚 rewarding to touch another person,鈥� he says. 鈥淏ut we know less about what drives this behavior, and how we perceive it to be rewarding.鈥�

Shea and Postdoc Yunyao Xie traced maternal motivation in mice to a region of the brain called the ventral tegmental area (VTA). They found that neurons in the VTA use dopamine to nurture maternal instincts through a process called reinforcement learning. When a mom picks up a crying child, their brain鈥檚 VTA neurons release dopamine. This creates an expectation of future rewards, driving them to pick the child up again the next time it cries. Shea says:

鈥淚t鈥檚 a very ancient mechanism in the brain that mice and humans and many other animals share. Dopamine is a complex molecule. It鈥檚 important for motion, reward, and motivation, but in this case, dopamine is actually instructing the behavior and reinforcing it.鈥�

To observe reinforcement learning in action, Shea鈥檚 team built an enclosure with two chambers. They placed a mouse on one side and a pup on the other, behind one of two doors. They then played specific sounds to signal whether the pup was present and if it was behind door number one or two. Each time the mouse heard a sound and retrieved the pup, VTA neurons rewarded it with dopamine.

鈥淪witching the neurons off in every trial prevented the mice from learning maternal behaviors,鈥� Shea says. 鈥淏ut switching them off every other trial only slowed the learning down. By doing this, we could see that switching the neurons off didn鈥檛 immediately affect maternal behavior. Instead, it affected the behavior on future trials.鈥�

Understanding how social contact is encouraged in mice gives researchers a clue about VTA neurons鈥� involvement in rewarding other behaviors. It also points to reinforcement learning鈥檚 role in how humans may perceive rewards.

Shea is now digging deeper into how VTA neurons work together and influence different types of social contact. He hopes to uncover the mental mechanisms behind human interactions. This may lead to a better understanding of how neurodevelopmental disorders affect people鈥檚 perceptions of social contact and reward.

鈥淭his is a very basic mechanism,鈥� Shea says. 鈥淯nderstanding it is important both for helping people with conditions like autism and for answering fundamental questions about the brain that will inform future work.鈥�

Written by: Nick Wurm, Communications Specialist | [email protected] | 516-367-5940

Funding

National Institute of Mental Health, Charles and Marie Robertson Foundation, The Feil Foundation

Citation

Xie, Y., et al., 鈥淎 dopaminergic reward prediction error signal shapes maternal behavior in mice鈥�, Neuron, December 20, 2022. DOI: