Does Covid-19 Leave Lasting Traces in the Brain?

Since the beginning of the pandemic, Covid-19 has affected millions of people worldwide. While respiratory symptoms are the most well-known, recent research shows that the virus can also durably affect the brain, even after recovery. An in-depth analysis of changes in the brain’s white matter in former patients reveals subtle but significant alterations, which may explain certain cognitive and psychiatric disorders observed after infection.

The brain consists of billions of nerve fibers that connect its different regions. These fibers, called white matter, enable the rapid transmission of information. Advanced imaging techniques, such as magnetic resonance imaging, allow the study of the structure of these fibers by measuring the diffusion of water within them. In individuals who have contracted Covid-19, alterations have been observed in several key areas, particularly in the corpus callosum, which connects the two cerebral hemispheres, as well as in the thalamic radiations and longitudinal fasciculi, which are involved in memory, attention, and emotions.

These changes may be related to how the virus enters the nervous system. It is now established that Covid-19 can infect neurons, either directly or by triggering an excessive inflammatory response. This inflammation, along with the oxidative stress it generates, can damage nerve fibers and disrupt their function. The consequences sometimes manifest as memory disorders, concentration difficulties, increased mental fatigue, or even depressive or anxious symptoms.

Studies show that these changes in brain structure are more pronounced in patients who experienced severe forms of the disease, but they can also affect those who had a mild infection. For example, alterations have been detected in regions such as the orbitofrontal cortex and the cingulate cortex, which play a role in emotion regulation and decision-making. These observations suggest that even a mild infection can leave traces in the brain, influencing mental well-being and cognitive abilities in the long term.

Another concerning aspect involves individuals who lost their sense of smell during the infection. Research indicates that this loss may be linked to damage in brain areas associated with olfaction, such as the olfactory bulb and orbitofrontal regions. These alterations could persist long after other symptoms have disappeared, affecting quality of life.

Scientists emphasize the importance of long-term follow-up for patients who have contracted Covid-19 to better understand the progression of these brain changes and their consequences. These findings also open avenues for exploring potential links between Covid-19 and an increased risk of neurodegenerative diseases, such as Alzheimer’s disease, although further research is needed to confirm this hypothesis.

In summary, Covid-19 is not limited to respiratory damage. Its effects on the brain, though often invisible, can be profound and lasting, influencing cognition, mood, and behavior. These results highlight the importance of considering neurological sequelae in the management of patients, even after their apparent recovery.

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Official Study Source

DOI: https://doi.org/10.1007/s11682-026-01084-3

Title: Brain microstructural alterations in COVID-19: a systematic review of diffusion weighted imaging studies

Journal: Brain Imaging and Behavior

Publisher: Springer Science and Business Media LLC

Authors: Ali Jahanshahi; Soheil Mohammadi; Mohammad Amin Salehi; Mahsa Dolatshahi; Sina Mirakhori; Negin Frounchi; Seyed Sina Zakavi; Hamid Harandi; Hosein Ghasempour; Cyrus A. Raji