Figure 3. CA3 associative network activation differs across
investigated mouse strains. (A) Hippocampal Schaffer
collaterals were electrically stimulated, and evoked local field
potential recordings were obtained from CA3 and CA1 pyramidal layers.
Antidromic and orthodromic population spike (PS) areas (ms.mV) were
calculated for stimulation intensities ranging from 0 to 50 µA.(b) Representative antidromic and orthodromic population spikes
in the CA3. Note the strong reduction of orthodromic responses in 129
mouse strain. CA3 IO curves (B6J: N=5 mice, n=18 slices; B6N: N=5 mice,
n=14 slices; 129, N=5 mice, n=16 slices) (c) of antidromic and(d) orthodromic population spikes showing a slight reduction in
antidromic population spikes and a strong reduction of orthodromic
population spikes of 129 strains in comparison to B6J strain.(e) Reduced CA3 associative network activation in 129 mouse
strain calculated via normalized orthodromic population spike responses.
For this purpose, orthodromic responses were divided to corresponding
antidromic responses and were averaged across 5 stimulation strengths.(f) Representative orthodromic population spikes in the CA1.(g) CA1 IO curves (B6J: N=5 mice, n=13 slices; B6N: N=5 mice,
n=12 slices; 129, N=5 mice, n=12 slices) showing similar population
spike areas across investigated strains. Statistical comparison for(c), (d), (g): two-way repeated measures ANOVA followed by
posthoc comparison using Fisher LSD Method with Greenhouse–Geisser
correction. Statistical comparison for (e): Kruskal-Wallis One
Way Analysis of Variance on Ranks followed by posthoc comparison using
Dunn´s Method. Post-hoc statistical differences between strains B6J and
129 are indicated via #p<0.05 and ###p<0.001.
Post-hoc statistical differences between substrains B6J and B6N are
indicated via *p<0.05. Data are presented ± standard error of
mean (SEM). Empty circles represent individual data points.