Table 5.

Multiple regressions for the confirmation sample. Each model quantifies the contribution of mean activation and trial-by-trial activation variability to WJ-III Letter Word Identification raw scores

Experimental condition	Region	Regressor	β	SE	ΔAIC	ΔBIC	ΔR2adj	F	pa
Print	Left IFGtr	Mean activation	−0.062	0.139	1.76	3.23	−0.014	0.200	0.658
		Activation variability	0.465	0.142	−8.70	−7.23	0.171	10.7	0.003
	Left thalamus	Mean activation	−0.003	0.141	2.00	3.47	−0.021	0.001	0.982
		Activation variability	−0.037	0.145	1.92	3.39	−0.019	0.065	0.801
Speech	Left STG	Mean activation	0.214	0.152	−0.189	1.28	0.022	1.98	0.170
		Activation variability	−0.179	0.152	0.461	1.93	0.009	1.38	0.250
	Left thalamus	Mean activation	0.178	0.156	0.545	2.01	0.007	1.30	0.263
		Activation variability	−0.121	0.156	1.32	2.79	−0.009	0.598	0.446

In all models, removal of the activation variability term did not affect the significance of the mean activation term.

^aFor this confirmatory analysis, we adopted a Bonferroni-corrected alpha threshold for significance of 0.0125 (0.05 divided by 4, the total number of models tested).