Structural and functional changes of the visual cortex in early Huntington's disease.

Emma M Coppen,Jeroen Van Der Grond,Anne Hafkemeijer,Raymund A C Roos,Jurriaan J H Barkey Wolf

doi:10.1002/hbm.24322

Abstract

Huntington's disease (HD) is an autosomal‐dominant inherited neurodegenerative disorder characterized by motor disturbances, psychiatric disturbances, and cognitive impairment. Visual cognitive deficits and atrophy of the posterior cerebral cortex are additionally present in early disease stages. This study aimed to assess the extent of structural and functional brain alterations of the visual cortex in HD gene carriers using different neuroimaging modalities. Structural and functional magnetic resonance imaging data were acquired from 18 healthy controls, 21 premanifest, and 20 manifest HD gene carriers. Voxel‐based morphometry (VBM) analysis and cortical thickness measurements were performed to assess structural changes in the visual cortex. Brain function was measured by assessing neuronal connectivity changes in response to visual stimulation and at rest in visual resting‐state networks. Multiple linear regression analyses were performed to examine the relationship between visual cognitive function and structural imaging measures. Compared to controls, pronounced atrophy and decreased neuronal function at rest were present in associative visual cortices in manifest HD. The primary visual cortex did not show group differences in cortical thickness and in vascular activity after visual stimulation. Thinning of the associative visual cortex was related to worse visual perceptual function. Premanifest HD gene carriers did not show any differences in brain structure or function compared to controls. This study improves the knowledge on posterior brain changes in HD, as our findings suggest that the primary visual cortex remains preserved, both structurally and functionally, while atrophy of associative visual cortices is present in early HD and linked to clinical visual deficits.

Highlights

Visual processing is involved in routine daily functioning, such as walking, driving a car, and in social communication
This study showed that changes in the visual cortex and visual cognitive deficits are present in early manifest Huntington's disease (HD) gene carriers, but not in premanifest gene carriers
The most pronounced volume loss and cortical thinning in manifest HD was found in the associative visual cortices, namely the lingual and fusiform gyri and lateral occipital cortex

Summary

Introduction

Visual processing is involved in routine daily functioning, such as walking, driving a car, and in social communication. In Huntington's disease (HD), an autosomal-dominant inherited neurodegenerative disorder, progressive structural changes in the posterior cerebral cortex can be detected in early stages of the disease, while frontal and temporal regions remain less affected Cognitive decline mainly involves progressive impairment in executive function (Dumas, van den Bogaard, Middelkoop, & Roos, 2013). Neuropsychological studies assessing visual cognitive function in HD reported impairments in several visual domains, tasks involving visual object perception (Gómez-Tortosa, del Barrio, Barroso, & García Ruiz, 1996; Lemiere, Decruyenaere, Evers-Kiebooms, Vandenbussche, & Dom, 2004), facial emotion recognition (Bora, Velakoulis, & Walterfang, 2016; Kordsachia, Labuschagne, & Stout, 2017), visuospatial processing, and visual working memory Neuropsychological studies assessing visual cognitive function in HD reported impairments in several visual domains, tasks involving visual object perception (Gómez-Tortosa, del Barrio, Barroso, & García Ruiz, 1996; Lemiere, Decruyenaere, Evers-Kiebooms, Vandenbussche, & Dom, 2004), facial emotion recognition (Bora, Velakoulis, & Walterfang, 2016; Kordsachia, Labuschagne, & Stout, 2017), visuospatial processing, and visual working memory (E. Dumas et al, 2012; Johnson et al, 2015; Labuschagne et al, 2016)

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