Dear Colleagues,

Cov2 infection appears to be complex, and the effects of infection can extend well beyond the respiratory system by unleashing what many refer to as a "storm" or "viral fire" in various organs and apparatuses of our body. Neurological manifestations are reported from 22% to 25% in various studies. These include acute cerebrovascular disease, alterations in consciousness, movement difficulties, seizures, status epilepticus, dementia, Parkinsonian syndrome, anxiety syndrome, depression, and psychosis. Among the acute cerebrovascular disorders, the most common is ischemic stroke. Encephalitis is reported in <1% of patients, but up to 6.9% in critically ill patients. Additionally, patients with a pre-existing neurological disease may have an aggravation of symptomatology as a severe COVID-19 clinical picture. There is also increasing evidence for what is called Post-Intensive Care Syndrome (PICS): patients treated in intensive care, at discharge from the same, may present a range of symptoms such as physical disabilities, cognitive impairment, and psychiatric abnormalities, such as muscle weakness, insomnia, depression, anxiety, delirium, and encephalopathy. Muscle weakness afflicts 33% of patients on mechanical ventilation and 50% of patients with sepsis; cognitive impairment afflicts 30% to 80% of patients. Patients recovering from COVID-19 may frequently experience cognitive abnormalities even several months after hospital discharge. (This is known as Long Covid or post-Covid syndrome). The onset of neurological and neuropsychological disorders and clinical manifestations often persists after infection, representing a kind of continuation of the disease. Among the detected effects, an increase in fatigue and a deficit in concentration, memory and cognitive speed are highlighted as persistent.

These symptoms also correspond to detectable changes in specific brain areas. The anatomical changes are "seen", not only in cognitive tests but also in brain imaging, particularly in the volume of grey matter. In those who have had COVID-19, compared to those who have not been infected, alterations are observed in the olfactory cortex and a region called the parahippocampal gyrus, parts of the brain which are responsible for the sense of smell and memory. In particular, the hippocampal gyrus is involved both in the formation of memory and in the retrieval of memories related to the past.

These long-term effects may affect work and daily life, even in younger subjects. Research should carefully evaluate the progression of post-COVID disorders and test the effectiveness of rehabilitation interventions.

The goal of this Special Issue is to collect key experimental and theoretical research linking state-of-the-art knowledge about the impact of COVID-19 on brain structures and functions. It aims to address the neurobiological and neuropsychological COVID-19 infection sequelae, as well as the influences that they have on daily living behaviour. In particular, we aim to address currently unresolved questions about COVID-19. To date, what is the profile of neurological and neuropsychological alteration selectively associated with infection? Do different variants of infection have a peculiar and recognisable impact? What are the neural correlates of cognitive–behavioural alterations typical of PICS and Long-Covid? What are the effects on the functional connectome? Is it possible for these changes to regress and resolve over time?

The neurocognitive approach has previously highlighted the relationship between brain pathology, neurological and neuropsychological impairment. This type of approach has proven to be extremely effective in the case of COVID-19. A winning example comes from:

Douaud, G., Lee, S., Alfaro-Almagro, F. et al. SARS-CoV-2 is associated with changes in brain structure in UK Biobank. Nature (2022). https://doi.org/10.1038/s41586-022-04569-5

This Special Issue is intended to provide an opportunity for researchers of different perspectives to discuss recent progress. COVID-19-related topics of interest include direct vs. indirect mechanisms of brain damage; neurological sequels of brain infection; cognitive dysfunctions and psychological effects; and the impact of COVID-19 on patients with pre-existing brain disorders.

We invite experts from cognitive, clinical, and experimental neuroscience, computational neuroscience, neurology, neuropsychology, neurophysiology, psychology, psychophysiology, psychiatry, and public health.

Researchers using various methods—including behavioural experiments, structural and functional neuroimaging, observational methods, and neuropsychological assessment tools—are encouraged to contribute original empirical research articles. Meta-analyses, reviews, case reports, commentaries, and perspective opinions/articles on promising future directions are also welcome.

Dr. Sara Palermo
Guest Editor

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• COVID-19
• SARS-CoV-2
• post-intensive care syndrome
• long COVID
• post COVID
• cognitive impairment
• neurological sequelae
• functional MRI (fMRI)
• resting-state fMRI (rs-fMRI)
• Diffusion Tensor Imaging (DTI)
• voxel-based morphometry (VBM)