bioRxiv Subject Collection: Neuroscience's Journal
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Thursday, May 30th, 2024
| Time |
Event |
| 7:50a |
Dissecting the ocular impact of SARS-CoV-2 variants: Analysis of eye globe and retina in animal models
Neurological and ocular manifestations were reported in COVID-19 patients and in SARS-CoV-2 infected animal models. However, the effects of SARS-CoV-2 variants of concern (VoC) on the eyes and the retina remain unclear. Here, we investigate the cellular and molecular consequences of SARS-CoV-2 VoC infection on the eye and retina in mice and hamsters. Infection with the ancestral SARS-CoV-2 and the Gamma VoC induced a subtle increase in the eye volume of K18-hAce2 mice, but no morphological alteration was observed in hamsters eyes. Evaluation of the ocular tropism revealed that distinct SARS-CoV-2 VoC reached the eye globe, but not the retina of K18-hAce2 mice. In contrast, SARS-CoV-2 variants are detected in the hamsters retina during both acute infection and after disease recovery. Despite the presence of viral RNA, no inflammation was observed in the hamster retina, as evidenced by unchanged microglial cell density and unaltered gene expression of several immune mediators. Altogether, these findings indicate a limited impact of SARS-CoV-2 variants on the eye and retina. | | 8:17a |
Attentional propagation of conceptual information in the human brain
The visual environment is complicated, and humans and other animals accordingly prioritise some sources of information over others through the deployment of spatial attention. We presume that attention has the ultimate purpose of guiding the abstraction of information from perceptual experience in the development of concepts and categories. However, neuroscientific investigation has focussed closely on identification of the systems and algorithms that support attentional control, or that instantiate the effect of attention on sensation and perception. Much less is known about how attention impacts the acquisition and activation of high-level information in the brain. Here, we use machine learning of EEG and concurrently-recorded EEG/MRI to temporally and anatomically characterise the neural network that abstracts from attended perceptual information to activate and construct semantic and conceptual representations. We find that the trial-wise amplitude of N2pc - an ERP component closely linked to selective attention - predicts the rapid emergence of information about semantic categories in EEG. Similar analysis of EEG/MRI shows that N2pc predicts MRI-derived category information in a network including VMPFC, posterior parietal cortex, and anterior insula. These brain areas appear critically involved in the attention-mediated translation of perceptual information to concepts, semantics, and action plans. | | 8:17a |
Multimodal single-cell sequencing of the human cortex reveals neuronal vulnerability and activated glial cell states in focal cortical dysplasia
The role of the diverse brain cell types in focal cortical dysplasia (FCD) development and epileptogenicity is not fully understood. Here, we performed multi-omics single-cell sequencing to characterize the chromatin accessibility and transcriptomes of cortical lesions and non-lesion areas from individuals with FCD IIa and IIb, the most prevalent presentations of this neurodevelopmental disorder. Our integrative analyses of the multimodal cell atlas, encompassing 61,525 nuclei with paired open chromatin and gene expression, uncovered a selective loss of upper-layer excitatory neurons and identified a lesion-specific population expressing NEFM, a neurofilament associated with dysmorphic neurons. In glial compartments, we observed a shift towards immature astrocytic populations exhibiting features of reactive astrocytes and balloon cells. Moreover, we identified activated microglial cell states emerging in FCD IIb, indicating that neuroinflammation contributes to FCD pathogenesis. This multimodal cell atlas is a valuable resource for exploring the cellular landscape and informing novel therapeutic approaches for cortical malformations. |
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