Abstract
ObjectiveTo investigate changes of vision-related resting-state activity in pituitary adenoma (PA) patients with visual damage through comparison to healthy controls (HCs).Methods25 PA patients with visual damage and 25 age- and sex-matched corrected-to-normal-vision HCs underwent a complete neuro-ophthalmologic evaluation, including automated perimetry, fundus examinations, and a magnetic resonance imaging (MRI) protocol, including structural and resting-state fMRI (RS-fMRI) sequences. The regional homogeneity (ReHo) of the vision-related cortex and the functional connectivity (FC) of 6 seeds within the visual cortex (the primary visual cortex (V1), the secondary visual cortex (V2), and the middle temporal visual cortex (MT+)) were evaluated. Two-sample t-tests were conducted to identify the differences between the two groups.ResultsCompared with the HCs, the PA group exhibited reduced ReHo in the bilateral V1, V2, V3, fusiform, MT+, BA37, thalamus, postcentral gyrus and left precentral gyrus and increased ReHo in the precuneus, prefrontal cortex, posterior cingulate cortex (PCC), anterior cingulate cortex (ACC), insula, supramarginal gyrus (SMG), and putamen. Compared with the HCs, V1, V2, and MT+ in the PAs exhibited decreased FC with the V1, V2, MT+, fusiform, BA37, and increased FC primarily in the bilateral temporal lobe (especially BA20,21,22), prefrontal cortex, PCC, insular, angular gyrus, ACC, pre-SMA, SMG, hippocampal formation, caudate and putamen. It is worth mentioning that compared with HCs, V1 in PAs exhibited decreased or similar FC with the thalamus, whereas V2 and MT+ exhibited increased FCs with the thalamus, especially pulvinar.ConclusionsIn our study, we identified significant neural reorganization in the vision-related cortex of PA patients with visual damage compared with HCs. Most subareas within the visual cortex exhibited remarkable neural dysfunction. Some subareas, including the MT+ and V2, exhibited enhanced FC with the thalamic pulvinar, which indicates an important role in the compensatory mechanism following visual impairment. In addition, neural dysfunction within the visual cortex was associated with neural activity alternation in the higher-order cognitive cortex, especially subareas in default mode network (DMN) and salience network (SN).
Highlights
The visual cortex is composed of more than 50 subareas, and each area has specific functions and connectivities [1]
It is worth mentioning that compared with healthy controls (HCs), V1 in pituitary adenoma (PA) exhibited decreased or similar functional connectivity (FC) with the thalamus, whereas V2 and MT+ exhibited increased FCs with the thalamus, especially pulvinar
We identified significant neural reorganization in the vision-related cortex of PA patients with visual damage compared with HCs
Summary
The visual cortex is composed of more than 50 subareas, and each area has specific functions and connectivities [1]. The synaptic connections of retinofugal neurons on area MT+ relay cells in the pulvinar and LGN have been identified, which suggests an alternative pathway that bypasses V1 directly to MT+/V5 [8, 9] This bypass advances MT+ as a potential substitute following a lesion at early age in V1, a notion that has been confirmed in previous studies [8, 10, 11]. Previous studies regarding visual cortex plasticity predominately recruited individuals with cortical lesion or blindness at early age. It remains unclear whether MT+ still, or if not, other subarea in visual cortex, play the role for compensation for partially vision-deprivation at adulthood with intact V1
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