Table 5.

Paths for serial mediation analyses of the effect of impulsivity/hyperactivity symptoms on inhibition accuracy via the pallidal-thalamic-motor pathway

	GPe/GPi				Thalamus				Motor				Accuracy
	b		SE	P	b		SE	P	b		SE	P	b		SE	P
Intercept	b0	0.75	0.16	<.001	b0,1	0.26	0.18	<.001	b0,2	1.05	0.27	<.001	b0,3	83.4	2.8	<.001
Impulsivity	a1	−0.35	0.13	.010	a2	−0.12	0.14	.376	a3	−0.25	0.21	.238	c1	−6.0	2.0	.004
GPe/GPi					d1,2	0.67	0.10	.008	d1,3	0.47	0.18	.008	b1	−1.8	1.8	.319
Thalamus									d2,3	0.37	0.14	.013	b2	−0.7	1.4	.618
M1													b3	2.7	1.0	.005
F, R2		6.87	0.06	.010		26.04	0.34	<.001		12.59	0.27	<.001		5.01	0.17	.001
Indirect Path											Effect	B. SE			B. CI
Total Indirect Effect											−0.61	0.91		−2.62	1.07
Impulsivity → GPe/GPi → Accuracy											0.62	0.77		−0.57	2.59
Impulsivity → GPe/GPi → Thalamus → Accuracy											0.17	0.27		−0.21	0.96
Impulsivity → GPe/GPi → M1 → Accuracy											−0.45	0.28		−1.36	−0.11	x
Impulsivity → GPe/GPi → Thalamus → M1 → Accuracy											−0.23	0.16		−0.76	−0.04	x
Impulsivity → Thalamus → Accuracy											0.09	0.20		−0.10	0.89
Impulsivity → Thalamus → M1 → Accuracy											−0.12	0.16		−0.64	0.06
Impulsivity → M1 → Accuracy											−0.67	0.69		−2.47	0.36

Note. x = P<.05; GPe/GPi=Globus Pallidus Pars Externa/Interna; M1=Primary Motor Cortex. t-statistic = b/SE. CI = confidence interval. B.SE = Bootstrapped Standard Error, B. CI = Bootstrapped confidence interval. The a paths are the associations between impulsivity and the mediator variables. The b paths are the associations between the mediator variable and inhibition accuracy. The c’ path is the direct effect of impulsivity on inhibition accuracy. The d path reflects the associations between the serial mediators.