Probing neuronal functions with precise and targeted laser ablation in the living cortex

Abstract

Targeted cell ablation is an important strategy for dissecting the function of individual cells within biological tissues. Here we developed an amplified femtosecond laser-coupled two-photon microscopy (AFL-TPM) system that allows instantaneous and targeted ablation of individual cells and real-time monitoring of neuronal network changes in the living mouse cortex. Through precise and iterative control of the laser power and position, individual cells could be ablated by a single femtosecond light pulse with minimum collateral damage. We further show that ablation of individual somatostatin-expressing interneuron increases the activity of nearby neurons in the primary motor cortex during motor learning. Through precise dendrotomy, we reveal that different dendritic branches of layer 5 pyramidal neurons are structurally and functionally independent. By ablating individual cells and their processes in a spatiotemporally specific manner, the AFL-TPM system could serve as an important means for understanding the functions of cells within the complicated neuronal network.