Trigeminal, visceral and vestibular inputs may improve cognitive functions by acting through the locus coeruleus and the ascending reticular activating system: A new hypothesis
Front. Neuroanat.. 2018-01-08; 11:
DOI: 10.3389/fnana.2017.00130
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De Cicco V(1), Tramonti Fantozzi MP(1), Cataldo E(2), Barresi M(3), Bruschini L(4), Faraguna U(1)(5), Manzoni D(1).
Author information:
(1)Laboratory of Sensorimotor Integration, Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, Pisa, Italy.
(2)Department of Physics, University of Pisa, Pisa, Italy.
(3)Institut des Maladie Neurodégénératives, University of Bordeaux, Bordeaux, France.
(4)Department of Surgical, Medical, Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy.
(5)Department of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Pisa, Italy.
It is known that sensory signals sustain the background discharge of the
ascending reticular activating system (ARAS) which includes the noradrenergic
locus coeruleus (LC) neurons and controls the level of attention and alertness.
Moreover, LC neurons influence brain metabolic activity, gene expression and
brain inflammatory processes. As a consequence of the sensory control of ARAS/LC,
stimulation of a sensory channel may potential influence neuronal activity and
trophic state all over the brain, supporting cognitive functions and exerting a
neuroprotective action. On the other hand, an imbalance of the same input on the
two sides may lead to an asymmetric hemispheric excitability, leading to an
impairment in cognitive functions. Among the inputs that may drive LC neurons and
ARAS, those arising from the trigeminal region, from visceral organs and,
possibly, from the vestibular system seem to be particularly relevant in
regulating their activity. The trigeminal, visceral and vestibular control of
ARAS/LC activity may explain why these input signals: (1) affect sensorimotor and
cognitive functions which are not directly related to their specific
informational content; and (2) are effective in relieving the symptoms of some
brain pathologies, thus prompting peripheral activation of these input systems as
a complementary approach for the treatment of cognitive impairments and
neurodegenerative disorders.