Mapping myelin in white matter with T1-weighted/T2-weighted maps: discrepancy with histology and other myelin MRI measures.

The ratio of T1-weighted/T2-weighted magnetic resonance images (T1w/T2w MRI) has been successfully applied at the cortical level since 2011 and is now one of the most used myelin mapping methods. However, no reports have explored the histological validity of T1w/T2w myelin mapping in white matter. Here we compare T1w/T2w with ex vivo postmortem histology and in vivo MRI methods, namely quantitative susceptibility mapping (QSM) and multi-echo T2 myelin water fraction (MWF) mapping techniques. We report a discrepancy between T1w/T2w myelin maps of the human corpus callosum and the histology and analyse the putative causes behind such discrepancy. T1w/T2w does not positively correlate with Luxol Fast Blue (LFB)-Optical Density but shows a weak to moderate, yet significant, negative correlation. On the contrary, MWF is strongly and positively correlated with LFB, whereas T1w/T2w and MWF maps are weakly negatively correlated. The discrepancy between T1w/T2w MRI maps, MWF and histological myelin maps suggests caution in using T1w/T2w as a white matter mapping method at the callosal level. While T1w/T2w imaging may correlate with myelin content at the cortical level, it is not a specific method to map myelin density in white matter.

Exploring the identity development of the budding neuroscientist at postgraduate level: a mixed-method study with perspectives from alumni and academics.

INTRODUCTION: Neuroscience represents one of the most exciting frontiers in scientific research. However, given the recency of neuroscience as a discipline, its inter- and multi-disciplinary nature, the lack of educational research on brain science training, the absence of a national or global benchmark and the numerous neuroscience subfields, the development of the academic neuroscientist identity across career stages remains obfuscated. Neuroscience is not predominantly taught at the undergraduate level but presents as a postgraduate specialism, accepting graduates from a wide range of primary disciplines. METHODS: This work represents the first mixed-method study exploring the development of the neuroscientist identity at the postgraduate level at a high-ranking, research-intensive UK University. It combines responses from standardised self-efficacy and professional identity questionnaires and qualitative data from nineteen semi-structured interviews with alumni and academics. RESULTS: Key findings on influences, identity transitions, curricular skills and sense of belonging have been discussed. The results obtained can be mapped against the theoretical framework proposed by Laudel and Gläser in 2008, although some minor changes to the model have been suggested. DISCUSSION: Implementing active learning strategies and experiential assessments, designing mentoring opportunities and creating spaces for interaction can favour the transition from students to neuroscientists and contribute to an inclusive and diverse neuroscientific community.

Dissociable effects of age and Parkinson's disease on instruction-based learning.

The cognitive deficits associated with Parkinson's disease vary across individuals and change across time, with implications for prognosis and treatment. Key outstanding challenges are to define the distinct behavioural characteristics of this disorder and develop diagnostic paradigms that can assess these sensitively in individuals. In a previous study, we measured different aspects of attentional control in Parkinson's disease using an established fMRI switching paradigm. We observed no deficits for the aspects of attention the task was designed to examine; instead those with Parkinson's disease learnt the operational requirements of the task more slowly. We hypothesized that a subset of people with early-to-mid stage Parkinson's might be impaired when encoding rules for performing new tasks. Here, we directly test this hypothesis and investigate whether deficits in instruction-based learning represent a characteristic of Parkinson's Disease. Seventeen participants with Parkinson's disease (8 male; mean age: 61.2 years), 18 older adults (8 male; mean age: 61.3 years) and 20 younger adults (10 males; mean age: 26.7 years) undertook a simple instruction-based learning paradigm in the MRI scanner. They sorted sequences of coloured shapes according to binary discrimination rules that were updated at two-minute intervals. Unlike common reinforcement learning tasks, the rules were unambiguous, being explicitly presented; consequently, there was no requirement to monitor feedback or estimate contingencies. Despite its simplicity, a third of the Parkinson's group, but only one older adult, showed marked increases in errors, 4 SD greater than the worst performing young adult. The pattern of errors was consistent, reflecting a tendency to misbind discrimination rules. The misbinding behaviour was coupled with reduced frontal, parietal and anterior caudate activity when rules were being encoded, but not when attention was initially oriented to the instruction slides or when discrimination trials were performed. Concomitantly, Magnetic Resonance Spectroscopy showed reduced gamma-Aminobutyric acid levels within the mid-dorsolateral prefrontal cortices of individuals who made misbinding errors. These results demonstrate, for the first time, that a subset of early-to-mid stage people with Parkinson's show substantial deficits when binding new task rules in working memory. Given the ubiquity of instruction-based learning, these deficits are likely to impede daily living. They will also confound clinical assessment of other cognitive processes. Future work should determine the value of instruction-based learning as a sensitive early marker of cognitive decline and as a measure of responsiveness to therapy in Parkinson's disease.

Current Status and Future Strategies for Mentoring Women in Neurology.

The American Academy of Neurology's (AAN) 2017 Gender Disparity Report identified improving mentorship as a key intervention to fill the leadership and pay gaps for women in neurology. Here we summarize the literature on mentoring women, provide an outline of ideal components of programs geared toward closing gender gaps, and present a mentoring program for AAN members. The strategies discussed share similarities with those for closing gaps related to race, ethnicity, and religion. Developing effective mentorship and sponsorship programs is essential to ensure a sufficiently diverse pool of academic faculty and private practitioners and to establish equal representation in leadership roles in this field.

Future of Neurology & Technology: Virtual and Augmented Reality in Neurology and Neuroscience Education: Applications and Curricular Strategies.

Virtual reality and augmented reality have become increasingly prevalent in our lives. They are changing the way we see and interact with the world and have started percolating medical education. In this article, we reviewed key applications of virtual and augmented realities in neurology and neuroscience education, and discussed barriers and opportunities for implementation in the curriculum. Although long-term benefits of these approaches over more traditional learning methods and the optimal curricular balance remain mostly unexplored, virtual and augmented reality can change how we teach neurology and neuroscience.

Training in Neurology: How Lessons Learned on Teaching, Well-being and Telemedicine During the COVID-19 Pandemic Can Shape the Future of Neurology Education.

The COVID-19 pandemic has a disruptive impact on neurology education, necessitating creative adjustments in the delivery of education, clinical training and wellbeing. In this piece, a group of educators reflects on challenges and lessons learnt on teaching, wellbeing and telemedicine, and how these can shape the future of neurology education. Developing standardized, rigorous evaluation of teaching methods and telemedicine, reinforcing wellbeing resources and promoting international educational collaborations can improve neurology training during and after the pandemic.

Active learning-based STEM education for in-person and online learning.

The COVID-19 global pandemic has forced the higher education sector to transition to an uncharted remote-learning format. This offers an opportunity to adopt active learning, which increases students' performance compared to lectures, narrows achievement gaps for underrepresented students, and promotes equity and inclusivity, as the basis of STEM education.

The status of neurology fellowships in the United States: clinical needs, educational barriers, and future outlooks.

The need for subspecialty-trained neurologists is growing in parallel with increasing disease burden. However, despite the immense burden of neurological diseases, like headache and neurodegenerative disorders, recruitment into these subspecialties remains insufficient in the United States. In this manuscript, a group of educators from the American Academy of Neurology's A.B. Baker Section on Neurological Education sought to review and discuss the current landscape of neurology fellowships in the United States, the factors driving fellowship recruitment and the educational barriers. Moreover, suggestions to potentially improve recruitment for under-selected fellowships, which can contribute towards an alignment between neurological education and neurological needs, and future educational scenarios are discussed.

The Effects of Working Memory Training on Brain Activity.

This study aimed to investigate if two weeks of working memory (WM) training on a progressive N-back task can generate changes in the activity of the underlying WM neural network. Forty-six healthy volunteers (23 training and 23 controls) were asked to perform the N-back task during three fMRI scanning sessions: (1) before training, (2) after the half of training sessions, and (3) at the end. Between the scanning sessions, the experimental group underwent a 10-session training of working memory with the use of an adaptive version of the N-back task, while the control group did not train anything. The N-back task in the scanning sessions was relatively easy (n = 2) in order to ensure high accuracy and a lack of between-group differences at the behavioral level. Such training-induced differences in neural efficiency were expected. Behavioral analyses revealed improved performance of both groups on the N-back task. However, these improvements resulted from the test-retest effect, not the training outside scanner. Performance on the non-trained stop-signal task did not demonstrate any transfer effect. Imaging analysis showed changes in activation in several significant clusters, with overlapping regions of interest in the frontal and parietal lobes. However, patterns of between-session changes of activation did not show any effect of training. The only finding that can be linked with training consists in strengthening the correlation between task performance accuracy and activation of the parietal regions of the neural network subserving working memory (left superior parietal lobule and right supramarginal gyrus posterior). These results suggest that the effects of WM training consist in learning that, in order to ensure high accuracy in the criterion task, activation of the parietal regions implicated in working memory updating must rise.

EEG, MEG and neuromodulatory approaches to explore cognition: Current status and future directions.

Neural oscillations and their association with brain states and cognitive functions have been object of extensive investigation over the last decades. Several electroencephalography (EEG) and magnetoencephalography (MEG) analysis approaches have been explored and oscillatory properties have been identified, in parallel with the technical and computational advancement. This review provides an up-to-date account of how EEG/MEG oscillations have contributed to the understanding of cognition. Methodological challenges, recent developments and translational potential, along with future research avenues, are discussed.

Detecting axonal injury in individual patients after traumatic brain injury.

Poor outcomes after traumatic brain injury (TBI) are common yet remain difficult to predict. Diffuse axonal injury is important for outcomes, but its assessment remains limited in the clinical setting. Currently, axonal injury is diagnosed based on clinical presentation, visible damage to the white matter or via surrogate markers of axonal injury such as microbleeds. These do not accurately quantify axonal injury leading to misdiagnosis in a proportion of patients. Diffusion tensor imaging provides a quantitative measure of axonal injury in vivo, with fractional anisotropy often used as a proxy for white matter damage. Diffusion imaging has been widely used in TBI but is not routinely applied clinically. This is in part because robust analysis methods to diagnose axonal injury at the individual level have not yet been developed. Here, we present a pipeline for diffusion imaging analysis designed to accurately assess the presence of axonal injury in large white matter tracts in individuals. Average fractional anisotropy is calculated from tracts selected on the basis of high test-retest reliability, good anatomical coverage and their association to cognitive and clinical impairments after TBI. We test our pipeline for common methodological issues such as the impact of varying control sample sizes, focal lesions and age-related changes to demonstrate high specificity, sensitivity and test-retest reliability. We assess 92 patients with moderate-severe TBI in the chronic phase (≥6 months post-injury), 25 patients in the subacute phase (10 days to 6 weeks post-injury) with 6-month follow-up and a large control cohort (n = 103). Evidence of axonal injury is identified in 52% of chronic and 28% of subacute patients. Those classified with axonal injury had significantly poorer cognitive and functional outcomes than those without, a difference not seen for focal lesions or microbleeds. Almost a third of patients with unremarkable standard MRIs had evidence of axonal injury, whilst 40% of patients with visible microbleeds had no diffusion evidence of axonal injury. More diffusion abnormality was seen with greater time since injury, across individuals at various chronic injury times and within individuals between subacute and 6-month scans. We provide evidence that this pipeline can be used to diagnose axonal injury in individual patients at subacute and chronic time points, and that diffusion MRI provides a sensitive and complementary measure when compared to susceptibility weighted imaging, which measures diffuse vascular injury. Guidelines for the implementation of this pipeline in a clinical setting are discussed.

Patterns of Focal- and Large-Scale Synchronization in Cognitive Control and Inhibition: A Review.

Neural synchronization patterns are involved in several complex cognitive functions and constitute a growing trend in neuroscience research. While synchrony patterns in working memory have been extensively discussed, a complete understanding of their role in cognitive control and inhibition is still elusive. Here, we provide an up-to-date review on synchronization patterns underlying behavioral inhibition, extrapolating common grounds, and dissociating features with other inhibitory functions. Moreover, we suggest a schematic conceptual framework and highlight existing gaps in the literature, current methodological challenges, and compelling research questions for future studies.

Active and Distance Learning in Neuroscience Education.

With social distancing and uncertainty about the complete re-opening of laboratories and campuses, there is a pressing need for a more flexible educational experience. Seizing this opportunity to integrate active learning into adaptive curricula can fast-forward neuroscience education at every level.