Based on a study in a combined human-mouse model system and a study in primary rat neurons, NPAS4 directly upregulates its own transcription. The complex of recombinant mouse Npas4 and Arnt2 was able to significantly induce transcription from a human NPAS4 gene reporter construct, with direct binding of mouse Npas4 to endogenous human Npas4 gene demonstrated (Bersten et al. 2014). In primary rat neurons, activated Npas4 significantly upregulates its own expression, measured by RNA-seq, with direct binding of Npas4 and its heterodimerization partners Arnt and Arnt2 to the Npas4 gene by ChIP-seq (Brigidi et al. 2019).