Check out some of the papers that were recently published by DMCBH members:
Teresa Liu-Ambrose: Physical exercise, cognition, and brain health in aging
Journal: Trends in Neurosciences
Exercise training can be a strategy to prevent cognitive and brain health decline in aging. This review discussed evidence on the impact of cognitive and brain health outcomes in healthy individuals and those at risk for cognitive impairment and neurodegeneration. It also reviewed neuroplastic adaptations to exercise and potential mechanisms, then concluded by highlighting areas for future research such as uncharted mechanisms and greater inclusion in samples.
Fidel Vila-Rodriguez: Trajectories of suicidal ideation during rTMS for treatment-resistant depression
Journal: Journal of Affective Disorders
Repeated transcranial magnetic stimulation (rTMS) is a safe and effective intervention for treatment resistant depression, however it is unclear how it affects suicidal ideation (SI), over the course of treatment. This study examined SI outcomes and trajectories in patients (n = 55) receiving rTMS to the right dorsolateral prefrontal cortex. SI and mood improved for most patients, but it was found that anxiety levels were risk factors for no improvement in both.
Journal: Journal of the Law and the Biosciences
Recently, advances in MRI physics and engineering have made highly portable and accessible MRI scanning a reality. This opens doors for field-based research, particularly in historically underrepresented populations. To address the ethical, legal and societal issues raised by portable MRI, an interdisciplinary working group was engaged in a multi-year structured process of analysis and consensus building, informed by research and the public. The consensus recommendations are presented in this article, addressing quality control, research design, safety, diversity, AI, data security, results and more.
Neil Cashman: Amyloidogenic regions in beta-strands II and III modulate the aggregation and toxicity of SOD1 in living cells
Journal: Open Biology
Mutations in the protein superoxide dimutase-1 (SOD-1) which promote misfolding and aggregation are linked to familial forms of the neurodegenerative disease amyotrophic lateral sclerosis (ALS). Currently, the most well-accepted hypothesis is that the aggregation of SOD-1 is somehow toxic to motor neurons, causing the characteristic motor neuron loss in ALS. Using in silico tools, researchers predicted amyloidogenic regions in the ALS associated SOD1-G85R mutant, finding 7 regions throughout the structure. Introducing proline residues into beta strands reduced SOD1-G85R aggregation and toxicity in cells. It was also found that proline mutants are less aggregation prone during proteasome inhibition and less toxic overall. This research highlighted the importance of a previously underappreciated region to the aggregation and toxicity of SOD-1 in ALS mutants and suggested that specific beta strands may be good targets for the development of SOD1 associated therapies.
Journal: eNeuro
Generally, clinical studies of major depression (MD) focus on group effects between patients and controls. Less attention has been given to individual differences in brain function within groups, which is increasingly recognized as important and can potentially impact effect sizes for group effects. This study examined the magnitude of individual differences in relation to commonly investigated group differences related to MD. Functional MRI data from 107 participants was collected at baseline, 2 and 8 weeks during which patients received the antidepressant escitalopram or no intervention. Individual differences and common connectivity patterns across groups, patients and participants contributed most to the explained variance. Group differences related to diagnosis, treatment response and biological sex made small but significant contributions. It was found that cognitive control and attention areas had high individual variation, while primary sensorimotor regions showed less variation. Group differences were much smaller than individual differences in the context of MD treatment. This research suggested that examining individual differences and their potential clinical relevance may help improve clinical outcomes for MD.
Journal: Neurology
It is of importance to find noninvasive and accurate biomarkers of neurological Wilson disease (NWD), a rare inherited disorder in which copper levels build up in several organs, including the brain. Susceptibility imaging suggested that Wilson’s disease exhibits a distinctive pattern of metal deposition, particularly in subcortical regions. In a cross-sectional diagnostic study using a 7T MRI scanner, researchers aimed to identify a novel imaging feature for precise NWD diagnosis. They successfully identified a hyperintense strip along the lateral border of the globus pallidus, which showed high sensitivity and excellent specificity in diagnosing NWD, distinguishing it from other conditions, and monitoring disease progression. This finding represents a promising neuroimaging biomarker for NWD.
Journal: Human Brain Mapping
Multivariate techniques can be more useful for mapping the anatomy of complex neuropsychiatric disorders characterized by variations across distributed brain networks. Principal component analysis (PCA) was used to identify covariance patterns and relate them to clinical and demographic variables in a large generalizable data set containing individuals with bipolar disorders and controls. Researchers confirmed that cortical thickness in widespread regional networks was negatively correlated with relevant clinical and demographic variables such as diagnosis, age, BMI and treatments. The performance of PCA was compared to clustering analysis, and it was found to be a superior method for studying multivariate associations between brain structure and system level variables. PCA demonstrated a superior goodness of fit to clustering when predicting diagnosis and BMI.
Raymond Lam, Erin Michalak: Advancing equitable access to digital mental health in the Asia-Pacific region in the context of the COVID-19 pandemic and beyond: A modified Delphi consensus study
Journal: PLOS Global public health
The COVID-19 pandemic had an undeniable impact on mental health and well-being around the world. To prevent the spread, many in person health and social services were disrupted, leading to the rapid development of digital interventions. Although these technologies improved access to care, there was also the risk that access barriers would lead to increased inequities in at-risk populations. The study conducted a needs assessment and identified priorities related to equitable digital mental health approaches in the Asia Pacific region during the first year of the pandemic. Using a modified Delphi consensus methodology including two rounds of online surveys and online consultations, researchers engaged with policy makers, clinicians, service providers and those with lived experiences in mental health. Results indicated that vulnerabilities to negative mental health impacts and access barriers were indeed compounded during the pandemic. Access barriers included a lack of linguistically and culturally appropriate options, low levels of awareness and trust, low mental health literacy, poor access to technological infrastructure and devices and lack of policies and guidelines to support effective and equitable digital mental health interventions. Study results can inform the development and implementation of equitable digital interventions as they become more widespread.
Catharine Winstanley, Rebecca Todd: Short-term memory capacity predicts willingness to expend cognitive effort for reward
Journal: eNeuro
In our daily lives, we often decide if the effort required for a task is worth its potential reward. Past research in rodents indicates that willingness to deploy cognitive effort can be driven by differences in perceived reward value, depression, or chronic stress. However, factors such as short-term memory ability cannot be captured in rodents, and as such, the impact of it is not fully understood. Undergraduate participants were grouped into high and low effort groups for an online visual short term memory task. After completing a monetary incentive task, participants completed short term memory tasks where they could choose between low effort, low reward and high effort, high reward options. The results showed that only greater short term memory ability predicted whether participants chose a much higher number of high vs. low effort trials, while depressive traits, reward anticipation and chronic stress levels did not. This research suggested that effort decisions may be driven by ability more so than motivational factors like depression or chronic stress.
Journal: Neuroscience & Biobehavioural Reviews
Visual processing is well studied in neuroimaging, with recent innovations allowing study in younger age ranges. Theories such as the interactive specialization and maturational frameworks have been proposed to describe how the brain functionally develops, but they have not been systemically examined across the fMRI literature. The present study conducted a scoping review of 94 developmental visual fMRI studies to appraise these frameworks throughout childhood development. Across domains (such as early visual processing, naturalistic visual processing), many studies reported progressive development throughout childhood, but few studies describe the regressive or emergent changes necessary to fit the frameworks above. The authors suggested a need for the expansion of developmental frameworks and clearer reporting of both progressive and regressive changes with powerful longitudinal studies.
Sophia Frangou: Brain responses to intermittent fasting and the healthy living diet in older adults
Journal: Clinical and Translational Report
Diet can potentially promote brain health in metabolically impaired older individuals. In an 8-week randomized clinical trial involving 40 cognitively intact older adults with insulin resistance, the researchers examined the effects of two diets on brain health. The 5:2 intermittent fasting diet involves restricting calories to a quarter of the recommended daily intake for 2 consecutive days per week, while the USDA healthy living diet emphasizes healthy choices (fruits, vegetables, whole grains, lean proteins, and low-fat dairy) with a limitation of sugars, saturated fats and sodium. Intermittent fasting induced greater weight loss, but both diets had comparable effects in improving insulin signaling biomarkers in neuron-derived extracellular vesicles, decreasing the pace of biological aging on the brain in MRI scans, reducing brain glucose on magnetic resonance spectroscopy and improving blood biomarkers of carbohydrate and lipid metabolism. There were minimal changes in biomarkers for Alzheimer’s disease, but both diets improved executive function and memory. This study provides a blueprint for assessing brain effects of dietary interventions and motivates more research for brain health optimization through diet.
Manu Madhav: Closed-loop control and recalibration of place cells by optic flow
Journal: Nature Neuroscience
To understand the principles of neural computation, it is key to first examine the interplay between sensory input, endogenous neural dynamics and behavioural output. Hippocampal place cells offer an ideal model for studying this interaction because they respond to both internal signals related to self-motion and external sensory cues as an animal moves through its surroundings. To maintain an accurate internal “cognitive map” of its environment, the hippocampus combines signals about self-motion over time. Without stable external cues, however, errors can accumulate, causing the brain’s representation of position or direction to drift relative to the real world. Previous research indicated that external landmarks can recalibrate the gain of the path integration system in addition to preventing/correcting error. It’s unclear whether internal signals like optic flow alone can recalibrate this system or if precise external landmarks are necessary. To explore this, researchers used control theory principles to manipulate hippocampal place cells in rats using a virtual reality setup. By adjusting optic flow speed based on real-time brain activity, they found that they could control how the brain updates its spatial map and induce recalibration of its position-tracking system. This study revealed that the brain continuously adjusts how it processes conflicting internal signals to fine-tune its ability to track position, and this adjustment doesn’t always require clear external landmarks.
