Figure 1.

Age differences in summation of evoked field potentials in adolescent amygdala. The prefrontal cortex (PFC) was stimulated at different frequencies (10, 20, or 40 Hz, 10 pulses/train) while recording in the lateral (LAT) or basal (BA) nuclei of the amygdala. (A) Evoked local field potential (LFP) facilitation/depression depended on the train stimulation frequency, shown here as overlays of 10 consecutive responses (grey traces) and the overlaid average (black trace). (B) In the LAT, facilitation of LFPs at 20 Hz was suppressed in PND 72–75 rats (normalized value < 1.0) across the train, and significantly different than PND 39 rats (*p < 0.05, two-way ANOVA). In contrast LFPs showed similar facilitation between PND 72–75 and PND 39 at 10 Hz and similar depression at 40 Hz (p > 0.05, two-way ANOVA). (C) The summation ratio (last LFP/first LFP) was significantly lower in PND 72–75 rats at 20 Hz (*p < 0.05, post-hoc Holm-Sidak’s multiple comparisons test after two-way ANOVA). (D) In the BA, significant LFP facilitation was observed at 10 and 20 Hz, and this was greater in PND 72–75 compared to PND 39 rats (*p < 0.05, two-way ANOVA), while a similar depression was observed at 40 Hz (p > 0.05, two-way ANOVA). (E) The summation ratio was greater in PND 72–75 rats at 10 Hz and at 20 Hz compared to PND 39 rats (*p < 0.05, post-hoc Holm-Sidak’s multiple comparisons test after two-way ANOVA).