Fos expression does not reflect specific coding of experience

Poster Session E - Monday, April 15, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

ning ding¹ (21111520005@m.fudan.edu.cn), chenyun wu¹, yvjie xiao¹, peng yuan¹; ¹Fudan University, Shanghai , China

The relationship between neural activity and the expression of immediate early genes has been a crucial question in understanding how experience drives plastic changes in the brain. Although there have been many years of research, it remains unclear what kind of neuronal activity can induce the Fos protein. Previous studies indicate that cells with heightened activation by external stimulus are more likely to express Fos. However, this conclusion was primarily based on the analysis of averaged results from all neurons in the mouse. To test this model at the single-cell level in vivo, we employed transgenic mice crossbred between Trap2 and Ai9 strains, so that Fos drives the expression of red fluorescent protein tdTomato. With this setup, we compared calcium activities between neurons with high Fos expression and those showed low expression. We found that while the group trend remained consistent as previously reported, the conclusion does not hold at individual cell level, which leads to different interpretation of the results. These results indicate that while Fos-high neurons exhibit heightened calcium activity on a group level, but these features only weakly predict Fos expression on individual cell level, thus unlikely to be the singular factor determining Fos expression. Rather than selective response to external stimulus, intrinsic properties such as overall excitability and connectivity of the cells offer more accurate prediction of Fos expression at individual cell level. Our data suggest more complex interaction between neuron activity and Fos expression under physiological conditions.

Topic Area: LONG-TERM MEMORY: Episodic