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. 2006 Nov 21;4(12):e409. doi: 10.1371/journal.pbio.0040409

Figure 2. Entorhinal Glutamatergic Afferents onto Mature Neurons Generated in the Developing and Adult Hippocampus.

Figure 2

(A) Schematic diagram of experimental design for retroviral labeling and electrophysiological recordings.

(B) A paired experiment. Upper row: a RFP+ neuron was patched (cell “1”) and filled with Alexa Fluor 488 (green). Lower row: a neighboring GFP+ neuron (cell “2”) was subsequently patched and filled with Alexa Fluor 594 (red). Both DGCs are in the same field, although at different focal planes (see merge channel). At the end of the experiment, both cells display green and red fluorescence (merge). Scale bar indicates 10 μm.

(C) Schematic diagram of the DG showing the position of the bipolar electrodes for the stimulation of the MPP and LPP.

(D) Example of EPSCs from an adult-born DGC at Vhold = +50 mV (top) and −80 mV (bottom) elicited by LPP stimulation recorded in the presence of vehicle (“control”) or 20 μM DNQX + 100 μM AP-5. Scale bars indicate 20 ms, 40 pA (top) or 20 pA (bottom). Similar properties were observed in DGCs born during development (unpublished data)

(E) Example of a paired experiment. Sequential recordings of two neighboring pup and adult DGCs in response to paired-pulse stimulation (100-ms interval) of the MPP and LPP. Scale bars represent 25 ms, 50 pA.

(F) Paired-pulse ratio (left) and 20%–80% rise time (right) of EPSCs recorded from pup and adult DGCs upon stimulation of MPP and LPP (n = 11 to 15) Paired-pulse ratio was measured as the ratio between the amplitude of the second pulse over the first. Two-way analysis of variance (ANOVA) revealed a significant effect of MPP versus LPP for paired-pulse ratio (p = 0.0002) and rise time (p = 0.0017), but no significant effect of pup versus adult (Adu) for either parameter.

(G) Peak EPSC amplitude recorded in paired experiments from DGCs born during development (Pup) and adulthood (Adult) upon stimulation of the MPP (n = 15 pairs, p = 0.3, paired t-test) or LPP (n = 11 pairs, p = 0.049). Mean ± SEM is shown on the sides. Recordings were carried out in the presence of 20 μM BMI in slices obtained from mice aged 19–21 wk. Neurons were approximately 18 wk old (P7) and approximately 13 wk old (P42). All plots depict mean ± SEM.