COVID-19, SARS and MERS:A neurological perspective

Central to COVID-19 pathophysiology is an acute respiratory infection primarily manifesting as pneumonia. Two months into the COVID-19 outbreak, however, a retrospective study in China involving more than 200 participants revealed a neurological component to COVID-19 in a subset of patients. The observed symptoms, the cause of which remains unclear, included impaired consciousness, skeletal muscle injury and acute cerebrovascular disease, and appeared more frequently in severe disease. Since then, findings from several studies have hinted at various possible neurological outcomes in COVID-19 patients. Here, we review the historical association between neurological complications and highly pathological coronaviruses including SARS-CoV, MERS-CoV and SARS-CoV-2. We draw from evidence derived from past coronavirus outbreaks, noting the similarities and differences between SARS and MERS, and the current COVID-19 pandemic. We end by briefly discussing possible mechanisms by which the coronavirus impacts on the human nervous system, as well as neurology-specific considerations that arise from the repercussions of COVID-19.</p

Art, Intuition, and Identity in Ramón y Cajal

In the history of neuroscience, Cajal stands tall. Many figures in the late 19th and early 20th centuries made major contributions to neuroscience-Sherrington, Ferrier, Jackson, Holmes, Adrian, and Békésy, to name a few. But in the public mind, Cajal is unique. His application of the Golgi method, with an array of histologic stains, unlocked a wealth of new knowledge on the structure and function of the brain. Here we argue that Cajal's success should not only be attributed to the importance of his scientific contributions but also to the artistic visual language that he created and to his pioneering self-branding, which exploited methods of the artist, including classical drawing and the new invention of photography. We argue that Cajal created his distinctive visual language and self-branding strategy by interweaving an ostensibly objective research product with an intimately subjective narrative about the brain and himself. His approach is evident in the use of photography, notably self-portraits, which furthered broad engagement initially inspired by his scientific drawings. Through his visual language, Cajal made an impact in art and culture far beyond the bounds of science, which has sustained his scientific legacy.</p

Grey Matter Etymology and the neuron(e).

‘Neuron’ or ‘neurone’? While it is often assumed that these different spellings reflect usage of American versus British English, there are also inconsistencies within these cultural boundaries. Mehta et al. review historical, etymological and linguistic evidence concerning the spelling of ‘neuron(e)’ and conclude that the only correct spelling is ‘neuron’

Early clinical, radiological and EEG improvement following L-arginine infusion in SMART syndrome

Objectives: To report the clinical, radiological (MRI) and neurophysiological (EEG) changes in a case of SMART (stroke-like migraine attacks after radiation therapy) syndrome following treatment with intravenous L-arginine. Methods: A 60-year-old woman had, ten years prior, been diagnosed with primary CNS diffuse large B cell lymphoma, and was successfully treated with curative chemotherapy and whole brain radiotherapy. She presented acutely with left-sided headache, teichopsia and dysphasia following a chest infection. MRI of the brain showed striking left parieto-occipital gyral swelling, diffusion restriction, leptomeningeal enhancement, and increased cerebral blood volume. Her EEG showed an excess of slow activity diffusely, particularly over the left temporal lobe. A diagnosis of SMART syndrome was made. Intravenous L-arginine (0.5 g/kg) was administered. Results: A few hours post infusion, her migrainous headache subsided and her mentation improved. Her MRI brain performed six days post infusion showed reduced cortical swelling and hyperperfusion, and her EEG showed less temporal slowing. She continued to improve cognitively. Discussion: This is the first report of SMART syndrome with a response to L-arginine, reflected clinically by a measurable improvement in cognition, brain perfusion and EEG parameters, encouraging further clinical studies

Trials for neurodegenerative diseases:time to innovate

The remarkable progress in our understanding of the mechanisms underlying neurodegenerative diseases heralds an era when neurologists would be at the vanguard of regenerative medicine, instead of chroniclers of decline. To capitalise on these advances that are identifying ever more therapeutic candidates, whether repurposed or entirely new, there is an urgent need for refined methods to test these putative medicines in clinical trials. Our field has the opportunity to learn from innovations in trial design, particularly those pioneered in oncology

Montage Matters: The Influence of Transcranial Alternating Current Stimulation on Human Physiological Tremor

BACKGROUND: Classically, studies adopting non-invasive transcranial electrical stimulation have placed greater importance on the position of the primary "stimulating" electrode than the secondary "reference" electrode. However, recent current density modeling suggests that ascribing a neutral role to the reference electrode may prove an inappropriate oversimplification. HYPOTHESIS: We set out to test the hypothesis that the behavioral effects of transcranial electrical stimulation are critically dependent on the position of the return ("reference") electrode. METHODS: We examined the effect of transcranial alternating current stimulation (sinusoidal waveform with no direct current offset at a peak-to-peak amplitude of 2000 μA and a frequency matched to each participant's peak tremor frequency) on physiological tremor in a group of healthy volunteers (N = 12). We implemented a sham-controlled experimental protocol where the position of the stimulating electrode remained fixed, overlying primary motor cortex, whilst the position of the return electrode varied between two cephalic (fronto-orbital and contralateral primary motor cortex) and two extracephalic (ipsilateral and contralateral shoulder) locations. We additionally controlled for the role of phosphenes in influencing motor output by assessing the response of tremor to photic stimulation, through self-reported phosphene ratings. RESULTS: Altering only the position of the return electrode had a profound behavioral effect: only the montage with extracephalic return contralateral to the primary stimulating electrode significantly entrained physiological tremor (15.9% ± 6.1% increase in phase stability, 1 S.E.M.). Photic stimulation also entrained tremor (11.7% ± 5.1% increase in phase stability). Furthermore, the effects of electrical stimulation are distinct from those produced from direct phosphene induction, in that the latter were only seen with the fronto-orbital montage that did not affect the tremor. CONCLUSION: The behavioral effects of transcranial alternating current stimulation appear to be critically dependent on the position of the reference electrode, highlighting the importance of electrode montage when designing experimental and therapeutic protocols