Chuck Darwin<p>There is strong evidence of brain-related abnormalities in COVID-19. </p><p>However, it remains unknown whether the impact of <a href="https://c.im/tags/SARS" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>SARS</span></a>-<a href="https://c.im/tags/CoV" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>CoV</span></a>-2 infection can be detected in milder cases, <br>and whether this can reveal possible mechanisms contributing to brain <a href="https://c.im/tags/pathology" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>pathology</span></a>. </p><p>Here we investigated <a href="https://c.im/tags/brain" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>brain</span></a> <a href="https://c.im/tags/changes" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>changes</span></a> in 785 participants of UK Biobank (aged 51–81 years) who were imaged twice using magnetic resonance imaging, </p><p>including 401 cases who tested positive for infection with SARS-CoV-2 between their two scans<br>—with 141 days on average separating their diagnosis and the second scan<br>—as well as 384 controls. </p><p>The availability of pre-infection imaging data reduces the likelihood of pre-existing risk factors being misinterpreted as disease effects. </p><p>We identified significant longitudinal effects when comparing the two groups, including </p><p>(1) a greater reduction in grey matter thickness and tissue contrast in the orbitofrontal cortex and parahippocampal gyrus; </p><p>(2) greater changes in markers of tissue damage in regions that are functionally connected to the primary olfactory cortex; and </p><p>(3) a greater reduction in global brain size in the SARS-CoV-2 cases. </p><p>The participants who were infected with SARS-CoV-2 also showed on average a greater cognitive decline between the two time points. </p><p>Importantly, these imaging and cognitive longitudinal effects were still observed after excluding the 15 patients who had been hospitalised. </p><p>These mainly limbic brain imaging results may be the in vivo hallmarks of a degenerative spread of the disease through olfactory pathways, <br>of neuroinflammatory events, <br>or of the loss of sensory input due to anosmia. </p><p>Whether this deleterious effect can be partially reversed, or whether these effects will persist in the long term, remains to be investigated with additional follow-up.</p><p><a href="https://www.nature.com/articles/s41586-022-04569-5" rel="nofollow noopener noreferrer" translate="no" target="_blank"><span class="invisible">https://www.</span><span class="ellipsis">nature.com/articles/s41586-022</span><span class="invisible">-04569-5</span></a></p>