Fig. 4.
(A) For activity in cell 1, cc12 (blue) represents the “outbound” coupling measured with current injection into cell 1, and cc21 (green) represents “inbound” coupling. (B) Single-cell bursting in cell 1 (gray) with postsynaptic burstlets in cell 2. Scale bars, 15 mV, 25 ms. (C) Inbound cc21 before and after full bursts in cell 1. (D) Outbound cc12 before and after full bursts in cell 1. (E) Ratios of directional cc [black solid circles; division of the changes in (C) divided by the changes in (D) for each pair] and GC (open circles, P < 0.05 for both cc and GC) after full bursts in cell 1, plotted against initial values. (F) Bursts in cell1 (gray) in1 μM TTX. Scale bars, 10 mV, 25 ms. (G) Inbound cc21 before and after bursts in cell 1 in TTX. (H) Outbound cc12 before and after bursts in cell 1 in TTX. (I) Ratios of directional cc (red solid squares; P = 0.6) and GC (open squares; P = 0.76) after bursts in cell 1 in TTX, plotted against initial values. (J) Model of an asymmetrical gap junction as two parallel branches. RC represents the minimum conductance (maximum resistance) common to both sides of the gap junction, and RD represents additional, asymmetrical conductance in one direction.