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. 2017 Feb 15;37(7):1950–1964. doi: 10.1523/JNEUROSCI.3196-16.2017

Figure 2.

Figure 2.

Paired-pulse facilitation, basal synaptic strength, and transmitter release probability at excitatory synapses in CA1 region of dorsal and ventral hippocampus. A, Paired-pulse facilitation is significantly lower at ventral SC fiber synapses. **p < 0.001 (two-way ANOVA with Student-Newman-Keuls post hoc multiple-comparisons test). p = 1.6 × 10−14, F(1,57) = 104.7 (n = 12 dorsal and n = 9 ventral slices). Right, Traces represent fEPSPs evoked by stimulation pulses delivered with a 50 ms interpulse interval. Calibration: 1 mV, 10 ms. B, Comparison of presynaptic fiber volley amplitudes and postsynaptic fEPSP slopes for responses elicited by different intensities of SC fiber stimulation in dorsal (n = 17) and ventral (n = 18) hippocampal slices (p = 0.982, Student's t test: t(33) = 0.022). C, D, Amplitude (C) and frequency (D) of mEPSCs in dorsal and ventral CA1 pyramidal cells (n = 1843 events from 7 dorsal cells and 1815 events from 7 ventral cells). There was no significant difference in either the mean amplitude (dorsal: 23.0 ± 1.6 pA; ventral: 23.7 ± 1.0 pA, p = 0.71, Student's t test: t(11) = 0.378) or frequency of mEPSCs (dorsal: 1.7 ± 0.1 Hz; ventral: 1.7 ± 0.1 Hz, p = 0.94, Student's t test: t(11) = 0.076). E, Examples of mEPSCs recorded from dorsal and ventral pyramidal cells. Calibration: 20 pA, 100 ms. F, Example of the use-dependent block of NMDAR-mediated EPSCs in the presence of 40 μm MK-801 in a dorsal CA1 pyramidal cell. Synaptic stimulation was omitted during the first 10 min of MK-801 application. Inset, NMDAR-mediated currents recorded before, immediately after resuming synaptic stimulation in presence of MK-801, and after 20 stimulation pulses in presence of MK-801. Calibration: 100 pA, 50 ms. G, The activity-dependent inhibition of NMDAR-mediated EPSCs by MK-801 is not significantly different in dorsal (n = 6) and ventral (n = 7) pyramidal cells. Weighted decay time constants for the MK-801 inhibition of NMDAR EPSCs were 209 ± 10 s and 214 ± 33 s in dorsal and ventral cells, respectively (p = 0.88, Student's t test: t(11) = 0.155).