Table 1.

Standard random-effects model and multi-level random-effects model analyses

Standard two-level analysis
Intervention	Estimate (95% CI)	P value	τ2
Chronic excitation	–1.48 [–1.99, –0.965]	< 0.001	0.36
Chronic inhibition	–0.62 [–1.00, –0.23]	0.002	0.66
Multi-level analysis (considering animal cohorts)
Intervention	Estimate (95% CI)	P value	σ2 article	σ2 cohort
Chronic excitation	–1.58 [–2.58, –0.59]	0.002	1.31	0
Chronic inhibition	–0.58 [–1.09, –0.06]	0.028	0.55	0.29
Multi-level analysis (authorship bias assessment)
Intervention	Estimate (95% CI)	P value	σ2 cluster	σ2 article	σ2 cohort
Chronic excitation	–	–	–	–	–
Chronic inhibition	–0.58 [–1.09, –0.06]	0.028	0	0.55	0.29

CI: Confidence interval.