PET Imaging of Perceptual Learning-Induced Changes in the Aged Rodent Cholinergic System.

Étienne De-Villers-Sidani,Maryse E Thomas,Pierrette Gaudreau,Min Su Kang,Pedro Rosa-Neto,Jonathan Côté,Patrice Voss,Karen Ross,J Miguel Cisneros-Franco,David A Rudko

doi:10.3389/fnins.2019.01438

Abstract

The cholinergic system enhances attention and gates plasticity, making it a major regulator of adult learning. With aging, however, progressive degeneration of the cholinergic system impairs both the acquisition of new skills and functional recovery following neurological injury. Although cognitive training and perceptual learning have been shown to enhance auditory cortical processing, their specific impact on the cholinergic system remains unknown. Here we used [18F]FEOBV, a positron emission tomography (PET) radioligand that selectively binds to the vesicular acetylcholine transporter (VAChT), as a proxy to assess whether training on a perceptual task results in increased cholinergic neurotransmission. We show for the first time that perceptual learning is associated with region-specific changes in cholinergic neurotransmission, as detected by [18F]FEOBV PET imaging and corroborated with immunohistochemistry.

Highlights

The rules governing experience-dependent cortical plasticity vary during the lifespan
We show for the first time that perceptual learning is associated with region-specific changes in cholinergic neurotransmission, as detected by [18F]FEOBV positron emission tomography (PET) imaging and corroborated with immunohistochemistry
With our results on choline acetyltransferase (ChAT)+ cells, the control and experimental groups did not differ in overall nor layer-specific SST+ cell density (Figure 4D). These results suggest that training-related changes in [18F]FEOBV binding detected by PET imaging were associated with an overall increase in cholinergic neurotransmission, without any layer-specific changes

Summary

Introduction

The rules governing experience-dependent cortical plasticity vary during the lifespan. Plasticity is still possible in the adult brain, it occurs almost exclusively in the context of learning and requires sustained attention (Bavelier et al, 2010). Enhanced cortical plasticity during adulthood can be triggered by several mechanisms including deafferentation (Chino et al, 1992; Diamond et al, 1993; Van Brussel et al, 2011), disruption in the quality or quantity of sensory input (He et al, 2006; Zhou et al, 2011), direct manipulation of neuromodulatory systems (Rokem and Silver, 2010, 2013; Kang et al, 2014; Voss et al, 2016; Chamoun et al, 2017), and perceptual learning (de Villers-Sidani et al, 2010; Mishra et al, 2014; Voss et al, 2016). Adult neuroplasticity is partly regulated by the cholinergic system through its main neurotransmitter, acetylcholine (ACh), which facilitates attention and learning (Hasselmo and Sarter, 2011). The cholinergic system is subject to significant alterations

Objectives

Methods

Results

Conclusion