SLC32A1 and Alzheimer disease: In contrast to previous studies13,14, we targeted the expression of the stabilized step-function opsin (SSFO) to TRN neurons, and their terminals located in AD, by stereotactic injection of a EF1α-DIO-SSFO-EYFP or EF1α-DIO-EYFP (control) adeno-associated virus (AAV) in the anterior TRN of VGAT::IRES-Cre driver mice (Fig. 5a; see “Methods” section).