The global SARS‐CoV‐2 pandemic has contributed to more than 163 million confirmed infections and 3.3 million deaths worldwide. The severity of the pandemic has led to an unprecedented effort to develop multiple effective vaccines. Due to excellent safety and efficacy data from clinical trials, several vaccines were approved. We report a case series of postvaccinal encephalitis in temporal correlation to vaccination with ChAdOx1 nCov‐19. The diagnostic criteria for possible autoimmune encephalitis were fulfilled. Our patients responded well to immunosuppressive therapy with corticosteroids. The incidence has been estimated to be approximately 8 per 10 million vaccine doses. Complication of postvaccinal encephalitis after ChAdOx1 nCoV‐19 vaccination still appear to be very rare, but need to be diagnosed and treated adequately. Large pooled data from observational epidemiologic studies are necessary to verify causality. ANN NEUROL 2021;90:506–511

The excitability of the cerebral cortex can be modulated by various transcranial stimulation techniques. Transcranial direct current stimulation (tDCS) offers the advantage of portable equipment and could, therefore, be used for ambulatory modulation of brain excitability. However, modulation of cortical excitability by tDCS has so far mostly been shown by indirect measures. Therefore, we examined whether tDCS has a direct behavioral/perceptional effect. We compared tactile discrimination of vibratory stimuli to the left ring finger prior to, during and after tDCS applied for 7 min at 1-mA current intensity in 13 subjects. Stimulation was pseudorandomized into cathodal, anodal and sham conditions in a within-subject design. The active electrode was placed over the corresponding somatosensory cortex at C4 according to the 10-20 EEG system and the reference electrode at the forehead above the contralateral orbita. Cathodal stimulation compared with sham induced a prolonged decrease of tactile discrimination, while anodal and sham stimulation did not. Thus, cortical processing can be modulated in a behaviorally/perceptually meaningful way by weak transcranial current stimulation applied through portable technology. This finding offers a new perspective for the treatment of conditions characterized by alterations of cortical excitability.

Background and Purpose-Recent reports have described the efficacy of the hematopoietic growth factor granulocytecolony stimulating factor (G-CSF) in animal stroke models. Early clinical multicenter trials evaluating the effect of G-CSF in acute stroke and pilot clinical trials for the subacute phase are ongoing. To guide further development, a meta-analysis was performed to assess the effects of G-CSF on infarct size and sensorimotor deficits. Methods-Using electronic and manual searches of the literature, we identified studies describing the efficacy of G-CSF in animal models of focal cerebral ischemia. Two reviewers independently selected studies and extracted data on study quality, G-CSF doses, time of administration, and outcome measured as infarct volume and/or sensorimotor deficit. Data from all studies were pooled by meta-regression analyses. Results-Thirteen studies including 277 animals for infarct size calculation and 258 animals for assessment of sensorimotor deficit met the criteria for inclusion. Overall efficacy of G-CSF regarding infarct size reduction was 42%. Meta-regression analysis revealed a 0.8% (PϽ0.0001) decrease in infarct size per 1-g/kg increase in G-CSF dose when applied within the first 6 hours and a 2.1% (PϽ0.0001) decrease when applied later than 6 hours after induction of ischemia with a significant (Pϭ0.0004) greater infarct size reduction after delayed treatment. Sensorimotor deficits categorized into 3 subgroups improved between 24% and 40%. Conclusions-Our findings consolidate G-CSF as a drug that both reduces infarct size and enhances functional recovery.These effects are presumably dose dependent. In contrast to most other neuroprotectants, a beneficial outcome may also be achieved when treatment is delayed.

Background and Purpose-In aged humans, stroke is a major cause of disability for which no neuroprotective measures are available. Granulocyte-colony stimulating factor (G-CSF), a member of the cytokine family of growth factors, promotes brain neurogenesis and improves functional outcome after stroke in young animals. We tested the hypothesis that G-CSF provides a restorative therapeutic benefit in aged animals. Methods-Focal cerebral ischemia was produced by reversible occlusion of the right middle cerebral artery in 19-to 20-month-old male Sprague-Dawley rats. One hour after reperfusion, the aged rats were treated daily with 15 g/kg G-CSF and for 15 days total. Rats were behaviorally tested and the brains removed for analysis at 28 days poststroke. Results-G-CSF treatment after stroke exerted a robust and sustained beneficial effect on survival rate and running function. Transient improvement after G-CSF treatment could be observed for coordinative motor function on the inclined plane test and for working memory in the radial-arm maze test. At the cellular level, G-CSF treatment increased the number of proliferating cells in the subventricular zone and dentate gyrus and also increased the number of newborn neurons in the subventricular zone ipsilateral to the lesion. Conclusions-These results suggest that G-CSF treatment in aged rats has a survival-enhancing capacity and a beneficial effect on functional outcome, most likely through supportive cellular processes such as neurogenesis.