Recently, Yuexuan Li, a post-95 doctoral student in Yale School of Medicine, published her blockbuster study in Science as the first author, which is the first research revealing the neural mechanism in infant brain that integrates infant-mother social behaviors and thus providing a new perspective for understanding early social and emotional development.

The “research gap” may be a new “exploration direction”

In the natural state, how dose infant brain integrate social information with its mother? This question has plagued the field of neuroscience for years.

After graduating from undergraduate program in 2019, Yuexuan Li joined Dietrich’s research group and officially began this doctoral research project.

When searching relevant literature, she occasionally read a paper published in 2015 that unveiled the unique role of ZI^SST neurons in the developmental process of undetermined zones in the brains of infant mice. However, this paper did not mention the specific activities of ZI^SST neurons, which provided a new exploration direction for Yuexuan Li’s research.

The first experiment conducted by Yuexuan Li was to record the activity of ZI^SST neurons during social interaction between infant mice and mother mice.

Social contacts can activate ZI^SST neurons

Ultimately, the research team found that at the time when the mother mouse approaches, the ZI^SST neurons of the infant mouse will be activated.

Enduring hardship cleverly is necessary in scientific research

Nevertheless, any scientific research cannot be accomplished at one stroke. Although the team has successfully observed expected behavior and physiological response during neuron activation experiments, the situation became complicated when they attempted to suppress these neurons.

The research team has adopted many common inhibiting methods, and these methods showed efficacy in in vitro testing, but the results were not satisfactory in in vivo experiments.

Meanwhile, this research once entered a dead end, and Yuexuan Li also had the idea of flinch as a result. But finally under the support and encouragement from her mentor Dietrich, she decided to keep exploring.

A turning point emerged when the research team switched the experimental focus to manually activated neurons and paid attention to the crying behavior of infant mice. The experiment results indicated that the decrease of ZI^SST neurons reduced the crying behavior of infant mice caused by separation from their mothers, while slowing down the release of stress hormone, corticosterone.

Moreover, the research team also conducted conditional preference experiments and verified that activating ZI^SST neurons can promote infant mice to learn positive associations.

In September 2023, the research team submitted a paper to Science, and two months later, the paper was successfully accepted.

When reviewing the research, Yuexuan Li said, “when conducting neurobiology research, the luck is important, but working hard is also inevitable, and the key is to cleverly work hard. When facing problems, we should systematically identify and solve them and meanwhile effectively communicate with mentors.”

Enjoying the process of scientific research and not persisting in results

As a student of mentor Dietrich, Yuexuan Li is influenced by the spirit of free exploration of Dietrich and learns to do scientific research happily. She said, “When selecting projects, don’t limit research direction, maintain an open mind, and conduct wide explorations, so as to find more possibilities and inspiration. The aim of scientific experiments is to verify or challenge our hypothesis. Good research experiments are performed to prove oneself wrong, while failed experiments can sometimes provide truly valuable feedback.”

In May of this year, Yuexuan Li successfully graduated with a PhD from Yale University. Next year, she will continue her postdoctoral research in the research team of David J. Anderson, a biology professor at the California Institute of Technology in the United States.