Diverging patterns of plasticity in the nucleus basalis of Meynert in early- and late-onset blindness

Ji Won Bang; Russell W Chan; Carlos Parra; Matthew C Murphy; Joel S Schuman; Amy C Nau; Kevin C Chan

doi:10.1093/braincomms/fcad119

Diverging patterns of plasticity in the nucleus basalis of Meynert in early- and late-onset blindness

Brain Commun. 2023 Apr 11;5(2):fcad119. doi: 10.1093/braincomms/fcad119. eCollection 2023.

Authors

Ji Won Bang¹, Russell W Chan¹, Carlos Parra¹, Matthew C Murphy^{2

3}, Joel S Schuman^{1

4

5

6}, Amy C Nau^{3

7}, Kevin C Chan^{1

3

4

5

6

8}

Affiliations

¹ Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY 10017, USA.
² Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA.
³ Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA.
⁴ Neuroscience Institute, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY 10016, USA.
⁵ Center for Neural Science, College of Arts and Science, New York University, New York, NY 10003, USA.
⁶ Department of Biomedical Engineering, Tandon School of Engineering, New York University, New York, NY 11201, USA.
⁷ Korb and Associates, Boston, MA 02215, USA.
⁸ Department of Radiology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY 10016, USA.

Abstract

Plasticity in the brain is impacted by an individual's age at the onset of the blindness. However, what drives the varying degrees of plasticity remains largely unclear. One possible explanation attributes the mechanisms for the differing levels of plasticity to the cholinergic signals originating in the nucleus basalis of Meynert. This explanation is based on the fact that the nucleus basalis of Meynert can modulate cortical processes such as plasticity and sensory encoding through its widespread cholinergic projections. Nevertheless, there is no direct evidence indicating that the nucleus basalis of Meynert undergoes plastic changes following blindness. Therefore, using multiparametric magnetic resonance imaging, we examined if the structural and functional properties of the nucleus basalis of Meynert differ between early blind, late blind and sighted individuals. We observed that early and late blind individuals had a preserved volumetric size and cerebrovascular reactivity in the nucleus basalis of Meynert. However, we observed a reduction in the directionality of water diffusion in both early and late blind individuals compared to sighted individuals. Notably, the nucleus basalis of Meynert presented diverging patterns of functional connectivity between early and late blind individuals. This functional connectivity was enhanced at both global and local (visual, language and default-mode networks) levels in the early blind individuals, but there were little-to-no changes in the late blind individuals when compared to sighted controls. Furthermore, the age at onset of blindness predicted both global and local functional connectivity. These results suggest that upon reduced directionality of water diffusion in the nucleus basalis of Meynert, cholinergic influence may be stronger for the early blind compared to the late blind individuals. Our findings are important to unravelling why early blind individuals present stronger and more widespread cross-modal plasticity compared to late blind individuals.

Keywords: basal forebrain; blindness; choline; nucleus basalis of Meynert; plasticity.

Abstract

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