Table 1.

Spatial decay of electrical conduction is greater in Old vs. Young.

Distance (μm)	Young (-1nA) ΔVm2 (mV)	Old (-1nA) ΔVm2 (mV)	Old (-1.4nA) ΔVm2 (mV)
50	-12.5 ± 0.7	-9.0 ± 0.7*	-12.5 ± 0.9
500	-9.8 ± 0.6	-6.6 ± 0.6*	-9.1 ± 0.8
1000	-7.4 ± 0.4	-4.8 ± 0.4*	-6.7 ± 0.6
1500	-5.0 ± 0.3	-2.7 ± 0.3*	-3.8 ± 0.5*
2000	-3.5 ± 0.3	-1.5 ± 0.4*	-2.0 ± 0.5*

The standard current pulse microinjected at site 1 to evaluate a change in membrane potential at site 2 (ΔV_m2) at distances of 50-2000 μm was -1 nA. The ΔV_m2 response to -1 nA was reduced at all distances in Old (Column 3) vs. Young (Column 2). To achieve the same ΔV_m2 at the nearest distance (50 μm) required ~ 40% more current (-1.4 nA; Column 4) in Old. Despite the same ΔV_m2 at 50 μm; note progressively greater signal loss with distance in Old vs. Young (compare Column 2 with Column 4). These data are complementary to Figure 3E, F.

^*P < 0.05 vs. Young ΔV_m2 responses to -1 nA at the same distances (n = 12 for Young, n = 9 for Old).