Table 4. Results of secondary post hoc analyses exploring potential effects of laterality.

Region of Interest	Variables		Estimate (β)	t-value	p-value†
Left Post-Commissural Putamen
	Independent:
		Trait Impulsivity—SSP	.12	1.43	.92
	Covariates:
		Age	-.33	-3.91	p < .0001
		Total Brain Volume	.49	5.68	p < .0001
Right Post-Commissural Putamen
	Independent:
		Trait Impulsivity—SSP	.15	1.71	.96
	Covariates:
		Age	-.33	-3.73	p < .0001
		Total Brain Volume	.47	5.35	p < .0001

^†Results are reported as one-tailed tests.