Single cell analysis is revealing increasing diversity in gene expression profiles among brain cells. Traditional promotor-based viral gene expression techniques, however, cannot capture the growing variety among single cells. We demonstrate a novel viral gene expression strategy to target cells with specific microRNA expression using microRNA-guided neuron tags (mAGNET). We designed mAGNET viral vectors containing a CamKIIα-promoter and miR-128 binding sets, and labeled CamKIIα-positive cells with naturally low expression of miR-128 (Lm128C cells) in male and female mice. Even though CamKIIα has traditionally been considered as an excitatory neuron marker, our single cell sequencing results reveal that Lm128C cells are CamKIIα positive inhibitory neurons of parvalbumin or somatostatin subtypes. Further evaluation of the physiological properties of Lm128C cell in brain slices showed that Lm128C cells exhibit elevated membrane excitability with biophysical properties closely resembling those of fast-spiking...