AUTHOR=Viglione Aurelia , Mazziotti Raffaele , Pizzorusso Tommaso TITLE=From pupil to the brain: New insights for studying cortical plasticity through pupillometry JOURNAL=Frontiers in Neural Circuits VOLUME=17 YEAR=2023 URL=https://www.frontiersin.org/journals/neural-circuits/articles/10.3389/fncir.2023.1151847 DOI=10.3389/fncir.2023.1151847 ISSN=1662-5110 ABSTRACT=

Pupil size variations have been associated with changes in brain activity patterns related with specific cognitive factors, such as arousal, attention, and mental effort. The locus coeruleus (LC), a key hub in the noradrenergic system of the brain, is considered to be a key regulator of cognitive control on pupil size, with changes in pupil diameter corresponding to the release of norepinephrine (NE). Advances in eye-tracking technology and open-source software have facilitated accurate pupil size measurement in various experimental settings, leading to increased interest in using pupillometry to track the nervous system activation state and as a potential biomarker for brain disorders. This review explores pupillometry as a non-invasive and fully translational tool for studying cortical plasticity starting from recent literature suggesting that pupillometry could be a promising technique for estimating the degree of residual plasticity in human subjects. Given that NE is known to be a critical mediator of cortical plasticity and arousal, the review includes data revealing the importance of the LC-NE system in modulating brain plasticity and pupil size. Finally, we will review data suggesting that pupillometry could provide a quantitative and complementary measure of cortical plasticity also in pre-clinical studies.