Table 4. Regression parameters corresponding to linear and segmented fits for I_h sensitive electrophysiological properties of CA1 pyramidal neurons along the V–D axis.

	Linear regression				Segmented regression
										Breakpoint		Slopes comparison
	Cons.	Slope	Adj. R2	P-value	Cons.	Slope 1	Slope 2	Adj. R2	P-value	Location	P-value	Diff.	P-value
FR at RMP (Hz)	3.14	-0.02	-0.01	0.57	3.5	0.14	-0.09	-0.001	0.39	-1.2	0.39	0.23	0.21
Q (RMP)	2.08	0.002	-0.01	0.73	1.19	-0.012	0.024	-0.005	0.49	0.5	0.7	-0.03	0.23
FR at -65 mV (Hz)	3.06	-0.23	0.22	<0.0001	4.4	0.3	-0.3	0.23*	<0.0001	-2.1	0.006†	0.6	0.07
Q (-65 mV)	1.2	-0.03	0.15	<0.0001	1.18	-0.05	-0.009	0.155	<0.0001	0.09	0.946	-0.04	0.23
RS (at RMP)	-0.21	0.013	0.09	0.0007	-0.1	0.05	0.004	0.12*	0.0003	-1.8	0.017†	0.05	0.035‡
RS at -65mV	-0.22	0.028	0.29	<0.0001	-0.2	-0.038	-0.001	0.31*	0.0001	0.54	0.437	0.04	0.029‡

V–D gradient in I_h sensitive electrophysiological properties of CA1 pyramidal neurons was fitted by linear and segmented regressions. Linear regression had two factors: constant value (Cons.) and slope. Segmented regression had three factors: constant, slope of line one (slope 1) and slope of line two (slope 2). V–D change in a few electrophysiological properties fitted better with segmented regressions than linear regressions

^*significant increase in Adjusted R²;

^†significant estimation of change point;

^‡significant difference between the slopes of two lines in the segmented regression.