Supplementary Figure 5: Characterization of optogenetic activation of EC–dCA1 monosynaptic transmission by AOD-based laser stimulation system.
From: A distinct entorhinal cortex to hippocampal CA1 direct circuit for olfactory associative learning
(a) Representative traces of EPSCCRACM recorded from the CA1 PC (blue) and the CA2 GABAergic interneuron (red), which, respectively, show consistent mono-synaptic responses and variable poly-synaptic responses, evoked by 473-nm laser pulses with increasing intensities in the CRACM experiment. (b,c) Effects of applying GABAARs blocker picrotoxin (50 μM) on (b) the responsive map, (c) EPSCCRACM amplitudes and the response latency in the dCA1 PC. P = 0.29 and P = 0.004 for the amplitude and latency, respectively, calculated by the paired t-test. (d,e) Effects of application of TTX (0.5 μM) and 4-AP (100 μM) on (d) the discrete dendritic EPSCCRACM map, EPSCCRACM latency (bottom: averaged EPSCCRACM traces from the indicated locations in the map), and (e) the mean maximal amplitude of EPSCCRACM. Data were presented as mean±s.e.m. P = 0.01, measured by paired t-test. (f,g) Effects of HCN channel blocker ZD7288 (20 μM), slimilar as d,e. Note a slight increase of mean amplitude of EPSCCRACM after the ZD compound application. Data were presented as mean±s.e.m. P = 0.16, calculated by the paired t-test. (h) Blocking the GABAARs with picrotoxin (50 μM) does not affect the differential innervations of direct excitatory TA inputs from LEC to dCA1, compared to the data in Fig. 2e. P = 3.8 × 10-8, measured by Person’s Chi-square test. (i) Preserved differential innervations of LEC and MEC direct inputs to sPC and cPC in the distal, medial and proximal part of dCA1.
