The path from trigeminal asymmetry to cognitive impairment: a behavioral and molecular study
Open Access
- 26 February 2021
- journal article
- research article
- Published by Springer Science and Business Media LLC in Scientific Reports
- Vol. 11 (1), 1-17
- https://doi.org/10.1038/s41598-021-82265-6
Abstract
Trigeminal input exerts acute and chronic effects on the brain, modulating cognitive functions. Here, new data from humans and animals suggest that these effects are caused by trigeminal influences on the Locus Coeruleus (LC). In humans subjects clenching with masseter asymmetric activity, occlusal correction improved cognition, alongside with reductions in pupil size and anisocoria, proxies of LC activity and asymmetry, respectively. Notably, reductions in pupil size at rest on the hypertonic side predicted cognitive improvements. In adult rats, a distal unilateral section of the trigeminal mandibular branch reduced, on the contralateral side, the expression of c-Fos (brainstem) and BDNF (brainstem, hippocampus, frontal cortex). This counterintuitive finding can be explained by the following model: teeth contact perception loss on the lesioned side results in an increased occlusal effort, which enhances afferent inputs from muscle spindles and posterior periodontal receptors, spared by the distal lesion. Such effort leads to a reduced engagement of the intact side, with a corresponding reduction in the afferent inputs to the LC and in c-Fos and BDNF gene expression. In conclusion, acute effects of malocclusion on performance seem mediated by the LC, which could also contribute to the chronic trophic dysfunction induced by loss of trigeminal input.Funding Information
- University of Pisa
- I.A.C.E.R. S.r.l. Company
- 3P Implafavourite Company
- Ministero della Salute (GR-2011-02348998)
This publication has 108 references indexed in Scilit:
- Enriched environment and masticatory activity rehabilitation recover spatial memory decline in aged miceBMC Neuroscience, 2013
- Effects of chewing on cognitive processing speedBrain and Cognition, 2013
- Effects of chronic social defeat on expression of dopamine β‐hydroxylase in rat brainsSynapse, 2013
- Spatial memory decline after masticatory deprivation and aging is associated with altered laminar distribution of CA1 astrocytesBMC Neuroscience, 2012
- Methylphenidate normalizes elevated dopamine transporter densities in an animal model of the attention-deficit/hyperactivity disorder combined type, but not to the same extent in one of the attention-deficit/hyperactivity disorder inattentive typeNeuroscience, 2010
- Cellular expression of GDNF mRNA suggests multiple functions inside and outside the nervous systemCell and tissue research, 1996
- ENCODING OF TOOTH LOADS BY HUMAN PERIODONTAL AFFERENTS AND THEIR ROLE IN JAW MOTOR CONTROLProgress in Neurobiology, 1996
- Fos expression in the medullary dorsal horn of the rat after chronic constriction injury to the infraorbital nerveJournal of Comparative Neurology, 1995
- Neurotrophin-3 prevents the death of adult central noradrenergic neurons in vivoNature, 1994
- Differential Actions of Neurotrophins in the Locus Coeruleus and Basal ForebrainExperimental Neurology, 1993