Table 3.

Results of Regression Analysis of the Relationship between Void Size and Inter-Void Interval and between Void Size and EMG Properties

	Thoraco-lumbar				Mid-thoracic
	Intact		Transected		Intact		Transected
Independent Variable (z-scores)	Slope	r2	Slope	r2	Slope	r2	Slope	r2
Inter-void interval	0.49	0.29***	0.16¶¶¶	0.03***	0.56	0.29***	0.34¶¶¶	0.12***
Void duration	0.54	0.30***	0.53	0.33***	0.92	0.49***	0.43¶¶¶	0.21***
Pburst	0.29	0.05***	0.37	0.11***	0.35	0.04***	0.46¶¶	0.09***
P3–5	0.21	0.05***	0.24	0.07***	0.32	0.10***	0.17¶¶	0.03***
P8–12	−0.07	0.00	0.05	0.00	0.02	0.00	0.06	0.00
Bursting time	0.41	0.13***	0.53	0.30***	0.63	0.25***	0.52¶	0.19***
Silent period	0.52	0.19***	−0.04¶¶¶	0.00	0.39	0.16**	−0.13¶¶	0.02
Active period	0.31	0.13**	−0.05¶	0.00	0.19	0.03	0.07	0.01
Bursting period	0.51	0.22***	−0.06¶¶¶	0.00	0.40	0.17**	−0.06¶¶	0.00

Slope and r², slope and coefficient of determination for regression of void size on independent variable; void duration, time of urine weight increase; P_burst, power in bursting range of as a percent of total power; P_3–5, power at 3–5 Hz (i.e., low bursting frequencies) as a percent of total power; P_8–12, power at 8–12 Hz (i.e., high bursting frequencies) as a percent of total power; bursting time, cumulative time during void when power in bursting frequencies exceeds the power in the same range expressed as a percent of total power of amplitude-matched non-voiding epochs by 2 standard deviations; silent period, time during a single bursting cycle in which the external urethral sphincter electromyography (EUS EMG) was not active; active period, time during a single bursting cycle in which the EUS EMG was active; bursting period, duration of a single bursting cycle (i.e., active period + silent period). All variables were z-transformed prior to regression analysis to remove inter-animal differences in mean and variance. For r², asterisks denote significant relationships between the independent variable and void size. For slope, ^¶ denotes significant difference in slope, compared with intact. ^* or ^¶, p ≤ 0.05; ^** or ^¶¶, p < 0.01,^*** or ^¶¶¶, p < 0.001.