Figure 4. Effect of 3 hrs of incisor tooth movement without or with 70-g orthodontic force on the number (mean ± SEM) of Fos-like immunoreactive neurons (Fos-IR) in the trigeminal subnuclei: caudalis (SpVc) and interpolaris (SpVi), locus coeruleus (LC), parabrachial nucleus (PB), peri-aqueductal gray matter (PAG), and dorsal raphe (DR). *P < 0.05 in relation to control group where appliance was inserted without orthodontic force. Number of sections analyzed in parentheses.