Fig. 1.

NMDA receptor-mediated currents of excitatory recurrent synapses exhibited a slower decay in PFC versus V1. (A) microphotograph of the biocytin-labeled PFC layer 5 pyramidal neurons from a multiple-cell recording. (Scale bar, 100 μm.) (B) examples of single-pulse recordings of layer 5 P-P pairs from PFC and V1, respectively. When membrane potentials were held at −70 mV, the currents are predominantly mediated by AMPA receptors; whereas at + 60 mV with CNQX and picrotoxin in the bath solution blocking the AMPA and GABA_A channels, respectively, the currents were largely mediated by NMDAR channels. The NMDA currents of PFC recurrent synapses showed significantly slower decays compared to those in V1. (C) Summary graph showing the significant differences of NMDAR decays in the two cortical areas (P = 0.0007). In contrast, the NMDA/AMPA receptor ratios were similar, without statistically significant difference (P = 0.514).