correction: figure 6a was incorrectly labeled. the correct figure is provided below. the authors apologize for the error. correction: the present address for david sarruf was omitted, and the description of panel e in figure 5 was incorrect. the correct information is provided below. david a. sarruf's present address is: diabetes pharmacology, novo nordisk a/s, maaloev, denmark. figure 5 legend: (e) mice fed chow for 8 months show increased astrocyte number but no overlap of processes. the authors apologize for the error.correction: figure 6a was incorrectly labeled. the correct figure is provided below. the authors apologize for the error. correction: the present address for david sarruf was omitted, and the description of panel e in figure 5 was incorrect. the correct information is provided below. david a. sarruf's present address is: diabetes pharmacology, novo nordisk a/s, maaloev, denmark. figure 5 legend: (e) mice fed chow for 8 months show increased astrocyte number but no overlap of processes. the authors apologize for the error.