Fig. 13.

Summary of pharmacology experiments on adaptation to variance of injected current in isolated ganglion cells. The relative area of the linear filters in the presence of pharmacological agents is plotted against that in control Ringer's solution for a collection of cells. In each cell the variance of the injected current was increased ninefold to probe adaptation. Open symbols are experiments on cells with various blockers of Ca²⁺and K⁺ currents (Fig. 11): (○) 5 mmTEA, 2.5 mm 4-aminopyridine (4-AP), 100 μmCd²⁺, (▵) 20 mm TEA, 10 mm4-AP, 100 μm Cd²⁺, and (◊) 200 μm Ba²⁺, 400 μmCd²⁺, 500 nm apamin. Experiments were performed with 100 nm TTX (●) (Fig. 11). In all cells the static nonlinearities overlapped, and the effect of changing the variance was restricted to the linear filter. Holding currents were chosen so that the cell had the same mean firing rate in the presence and absence of toxin. Error bars were estimated as described in Materials and Methods.