Table 5.

Variances, beta's (β), p values, and 95% confidence intervals (CIs) for the best fitting models for age and NAcc activation (left and right), PDS, testosterone levels, BART, and all scales of the BIS/BAS questionnaire

	Variance	β	p	95% CI
	Variance	β	p	Lower	Upper
Nacc L
Random effect
Intercept	1.01			0.68	1.52
Fixed effects
Intercept		1.73	0.00	1.49	1.96
Age¹		1.38	0.59	−3.67	6.43
Age²		−9.44	0.00	−14.42	−4.45
Nacc R
Random effect
Intercept	0.83			0.50	1.41
Fixed effects
Intercept		1.87	0.00	1.64	2.11
Age¹		0.64	0.81	−4.48	5.76
Age²		−9.11	0.00	−14.18	−4.03
PDS
Random effect
Intercept	0.30			0.25	0.36
Fixed effects
Intercept		2.69	0.00	2.62	2.77
Age¹		14.61	0.00	13.26	15.97
Age²		−1.52	0.02	−2.75	−0.29
Age³		−2.86	0.00	−3.98	−1.74
Sex		−0.37	0.00	−0.48	−0.27
Age¹ × sex		−2.10	0.04	−4.13	−0.08
Age² × sex		2.57	0.01	0.71	4.43
Age³ × sex		1.07	0.23	−0.68	2.82
Testosterone
Random effects
Intercept	0.18			0.15	0.22
Fixed effects
Intercept		1.27	0.00	1.23	1.31
Age¹		3.36	0.00	2.26	4.45
Age²		−1.41	0.03	−2.65	−0.17
Age³		1.58	0.00	0.51	2.65
Sex		0.74	0.00	0.68	0.81
Age¹ × sex		8.25	0.00	6.80	9.70
Age² × sex		−5.32	0.00	−6.85	−3.79
Age³ × sex		−0.44	0.53	−1.81	0.93
BART
Random effects
Intercept	5.19			3.24	8.32
Age	0.33			0.20	0.54
Fixed effects
Intercept		11.26	0.00	10.90	11.62
Age¹		17.57	0.00	8.44	26.69
Age²		−16.11	0.00	−24.94	−7.27
BIS
Random effect
Intercept	2.51			2.18	2.88
Fixed effect
Intercept		19.54	0.00	19.18	19.90
BAS Drive
Random effect
Intercept	1.39			1.18	1.62
Fixed effect
Intercept		10.78	0.00	10.57	10.99
BAS Fun Seeking
Random effect
Intercept	0.97			0.79	1.19
Fixed effect
Intercept		11.70	0.00	11.53	11.88
BAS Reward
Random effect
Intercept	1.08			0.90	1.30
Fixed effect
Intercept		17.16	0.00	16.98	17.33

Linear age terms are represented by Age¹, quadratic age terms by Age², and cubic age terms by Age³.