The study, published in JAMA Network Open, found a reduction in gray matter thickness in specific regions of the brain, as well as changes in the volume of certain neural structures. These alterations were also correlated with changes in psychological characteristics.

The SARS-CoV-2 Omicron variant, first identified in November 2021, has raised concerns due to its numerous mutations, especially in the spike protein. Previous research has suggested that infections caused by various coronavirus variants, including Omicron, can lead to persistent symptoms that last for more than 90 days after recovery. These symptoms encompass a wide range, from dizziness and headaches to neuropsychiatric issues such as sleep disorders, depression, anxiety, and cognitive decline.

The study, led by Yanyao Du and his colleagues, aimed to investigate how the Omicron variant affects gray matter and the volumes of specific neural structures in the brains of male patients. Gray matter, a crucial component of the central nervous system, is characterized by its higher density of neuronal cell bodies, dendrites, and unmyelinated axons. The researchers were particularly interested in identifying the links between these brain changes and various psychological symptoms experienced by the participants.

The study involved 61 men who had undergone functional magnetic resonance imaging (fMRI) scans prior to contracting the SARS-CoV-2 Omicron virus. These men had undergone the imaging as part of a health screening between August and September 2022, and later became infected with the Omicron variant in January 2023. During the infection period, they revisited the clinic for further fMRI scans and completed psychological assessments. Seventeen of the participants also underwent follow-up assessments in April 2023. The average age of the participants was 43 years.

The researchers measured various psychological characteristics of the participants, including depression, anxiety, sleep problems, and emotional self-efficacy. They also conducted cognitive tests and evaluated clinical symptoms at different time points. The results revealed a decrease in gray matter thickness in specific regions of the brain, such as the left precuneus and right lateral occipital regions, following the Omicron infection. Additionally, the ratio of the right hippocampus volume to the total brain volume was found to diminish.

Furthermore, the study found that changes in gray matter thickness in the left precuneus were associated with more severe anxiety symptoms. On the other hand, a higher ratio of the right hippocampus volume to the total brain volume was linked to better performance on cognitive tests, specifically the Word Fluency Test.

The study's findings provide valuable insights into the effects of SARS-CoV-2 Omicron infection on brain health. However, it is important to note that the study had limitations. The participants were all men, and it is unclear whether the results would be the same for women. Additionally, there was only one follow-up neuroimaging done during the infection period.

The research, titled "Gray Matter Thickness and Subcortical Nuclear Volume in Men After SARS-CoV-2 Omicron Infection," was conducted by Yanyao Du and his team.