Fig. 4.

Shunting inhibition for I located at dendritic trunk and oblique branches. (A and B) Simulation results of k values (color-coded) for I (black dot) located at apical trunk (A) and oblique branch (B), with E scattered on dendritic arbor in stratum radiatum. (C–H) Experimental results. (C) I at oblique branch: k was not significantly different between two distal Es (E₁ and E₂) within the same branch (P = 0.89, paired t test). E₁ to E₂ distances were >70 μm in all experiments. Lines connect data from the same cell. (D) As in C except that Es were more proximal to I (P = 0.001). (E) I at the trunk: k was not significantly different between Es at the trunk (E₁) and at the first-order oblique branch (E₂, P = 0.92). I to E distances were kept constant. (F) I at oblique branch: k was significantly different between Es at the same and different branch (P < 0.001). (G) E at the trunk: k was significantly different between Is at the trunk (I₁) and at oblique branch (I₂, P = 0.031). The trajectory distance of I to the soma was kept constant. (H) The decay of k value as a function of distance between I₂ and the branch point for the configuration in G. Line indicates exponential fit (R = 0.97, length constant 44 μm).