Table 1.

Average peak rate at the time of the drop or jump

	Peak rate at event	Background rate	Specificity ratio
Drop cells	16.60	0.64	42.26
Jump cells	18.20	1.35	17.53
Drop + jump cells	14.07	2.29	7.78

For drop + jump cells, the higher value is included in the average. The peak and background rates are arithmetic averages; the specificity ratio is the geometric mean of the individual specificity ratios. For drop + jump cells, the background rate is higher and the specificity ratio is lower than for the other types because the second event evokes firing from the cell that is included in the background rate. The background rate for jump cells is not reliably greater than for drop cells. In contrast, the specificity ratio for drop cells is significantly higher than for jump cells (t₍₄₂₎ = 2.36; p = 0.023).