Loss of specific subpopulations of interneurons seen within various regions of the hippocampus.
Loss of interneurons is a characteristic often seen in the hippocampus of the NCLs. We divided the hippocampus into defined regions and stained sections for specific subpopulations of interneurons and subsequently counted the subpopulations within the sections. (A) PV+ interneurons decreased in the dentate gyrus (DG) at 9 months but remain unchanged in other areas where PV+ interneurons were present. (B) SOM+ interneurons were first decreased at 5 months in the hilus and stratum oriens with further decline observed at 9 months. Decline of SOM+ interneurons was also seen at 9 months in the stratum radiatum as well as the combined CA fields of the hippocampus. (C–D) A significant reduction in the number of CB+ interneurons was observed within the stratum oriens at 9 months when compared to WT. [Mean +/− SEM, n = 3 (*p≤0.05, **p≤0.01, ***p≤0.001, ****p≤0.0001)].