Science and Technology Daily, Beijing, March 14 (Reporter Zhang Mengran) What happens to the brain after the new crown infection?
In a neurology paper published recently in the British journal Nature, scientists described the changes in the human brain after new coronavirus infection, including changes in brain areas related to smell and memory.
The findings could reveal the damaging effects of COVID-19 and improve our understanding of how the disease spreads to the central nervous system.
Whether these effects persist in the long term, and whether they are partially reversible, remains to be studied.
While there is evidence that Covid-19 can cause brain-related dysfunction, most studies have focused on hospitalized critically ill patients and can only be based on post-infection imaging data.
The effect of the new coronavirus on the brain of patients with mild symptoms is still unknown, and studying these mild cases may reveal possible mechanisms that promote brain disease or brain damage.
This time, a team of scientists from the University of Oxford in the United Kingdom analyzed the brain changes of 785 people (51-81 years old) who had undergone two brain scans (average interval of 38 months) and received cognitive tests in the British Biobank.
A total of 401 people tested positive for Covid-19 between the two brain scans, 15 of whom were hospitalized; the remaining 384 served as an age- and sex-matched control group.
The team identified various long-term effects after infection (average interval between Covid-19 diagnosis and second scan was 141 days), including the emergence of gray matter thickness in the orbitofrontal cortex and parahippocampal gyrus (a brain region associated with smell and event memory) a larger reduction.
In addition, the team found evidence of tissue damage in brain regions related to the olfactory cortex and an average decrease in overall brain volume from subjects who had been infected with COVID-19.
On average, study subjects who had been infected with the new coronavirus also experienced greater cognitive decline between scans and were associated with atrophy of the cerebellum, which is known to be associated with cognitive function.
The researchers also conducted a controlled analysis in people with pneumonia unrelated to Covid-19, demonstrating that the changes were specific to Covid-19 rather than the general effects of respiratory disease.
The findings may suggest degenerative changes caused by COVID-19, whether through olfactory pathways, nervous system inflammation, or loss of sensory input due to anosmia.
Further research on the vulnerability of the affected brain regions in these subjects is needed in the future.