Multi-channel recordings of pre-LTP in the adult mouse ACC. A: results of one pre-LTP-showing channel (Ch. 39) from the superficial layer of one ACC slice. After the baseline response was stabilized for 20 min, a LFS protocol (2 Hz for 2 min) was applied in the presence of the NMDA receptor antagonist (AP-5, 50 μM, 38 min) and a GluK1-containing kainate receptor agonist (ATPA, 1 μM, 18 min). The synaptic potentiation could last for at least 1 h. B: summary of averaged data from 7 superficial channels of the same slice. C: pooled data for the superficial layer from 7 slices of 7 mice. D: summarized data for the deep layer of the ACC from 6 slices of 6 mice. E: PPR was decreased 1 h after the LFS + ATPA in one slice (averaged data of 7 channels). F: bar histogram showing the pooled data of PPR from 7 slices of 7 mice. Insets in A and D show representative fEPSP traces at time points indicated by the numbers in the graph. Sample traces in E are paired-pulse responses before (Pre) and 1 h after pre-LTP induction (Post). Calibration: 50 μV, 10 ms. Horizontal bars in A-E denote the period of AP5 or ATPA application as indicated. Arrows in A-E indicate the LFS application. Error bars in C, D and F represent SEM.