Figure 2.

Fluorescence intensity measured postmortem is decreased in neurons surrounding plaques and remains unaltered after environmental stimulation. a–f, Representative neurons from wild-type (WT) and transgenic (TG) mice that differ in their fluorescence intensity. Fluorescence intensity from transgenic neurons in the vicinity of plaques (shown in blue; a) was greatly overall reduced compared with wild-type neurons and remained unchanged after environmental stimulation (b, e). Interestingly, fluorescence intensity from neurons >100 μm away from plaques (c) was significantly higher than those from close to plaques and increased in the cell body (arrow) after environmental stimulation (d). Note that the intensity in the wild-type neurons started at an even higher level (e) and increased further after enriched environment (f) in the cell body (arrow) as well as in neurites (arrowhead). g–i, Intensity measurements confirmed that transgenic neurons had significantly decreased intensity (*p < 0.0001), and only wild-type neurons increased intensity in both cell bodies (*p < 0.0001) (g) as well as in neurites (*p < 0.0001) (h) after environmental enrichment. Scale bar: a–f, 20 μm.