A robust activity marking system for exploring active neuronal ensembles.

Andreas T Sørensen
Yonatan A Cooper
Michael V Baratta
Feng-Ju Weng
Yuxiang Zhang
Kartik Ramamoorthi
Robin Fropf
Emily LaVerriere
Jian Xue
Andrew Young
Colleen Schneider
Casper René Gøtzsche
Martin Hemberg
Jerry Cp Yin
Steven F Maier
Yingxi Lin


Understanding how the brain captures transient experience and converts it into long lasting changes in neural circuits requires the identification and investigation of the specific ensembles of neurons that are responsible for the encoding of each experience. We have developed a Robust Activity Marking (RAM) system that allows for the identification and interrogation of ensembles of neurons. The RAM system provides unprecedented high sensitivity and selectivity through the use of an optimized synthetic activity-regulated promoter that is strongly induced by neuronal activity and a modified Tet-Off system that achieves improved temporal control. Due to its compact design, RAM can be packaged into a single adeno-associated virus (AAV), providing great versatility and ease of use, including application to mice, rats, flies, and potentially many other species. Cre-dependent RAM, CRAM, allows for the study of active ensembles of a specific cell type and anatomical connectivity, further expanding the RAM system's versatility.