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1. Quantitative EEG Metrics for Determining HD-tDCS Induced Alteration of Brain Activity in Stroke Rehabilitation

   https://doi.org/10.1177/09226028251347427  

   Williamson, Jordan_N; James, Shirley_A; Mulyana, Beni; Kim, Sally; He, Dorothy; Li, Sheng; Sidorov, Evgeny_V; Yang, Yuan (June 2025, Restorative Neurology and Neuroscience)

   High-definition transcranial direct current stimulation (HD-tDCS) is a promising approach for stroke rehabilitation, which may induce functional changes in the cortical sensorimotor areas to facilitate movement recovery. However, it lacks an objective measure that can indicate the effect of HD-tDCS on alteration of brain activity. Quantitative electroencephalography (qEEG) has shown promising results as an indicator of post-stroke functional recovery. Therefore, this study aims to determine whether qEEG metrics could serve as quantitative measures to assess alteration in brain activity induced by HD-tDCS. Resting state EEG was collected from stroke participants before and after (1) anodal HD-tDCS of the lesioned hemisphere, (2) cathodal stimulation of the non-lesioned hemisphere, and (3) sham. The average power spectrum was calculated using the Fast Fourier Transform for frequency bands alpha, beta, delta, and theta. In addition, delta-alpha ratio (DAR), Delta-alpha-beta-theta ratio (DTABR), and directional brain symmetry index (BSI) were also evaluated. We found that both anodal and cathodal stimulation significantly decreased the DAR and BSI over various frequency bands, which are associated with reduced motor impairments and improved nerve conduction velocity from the brain to muscles. This result indicates that qEEG metrics DAR and BSI could be quantitative indicators to assess alteration of brain activity induced by HD-tDCS in stroke rehabilitation. This would allow future development of EEG-based neurofeedback system to guide and evaluate the effect of HD-tDCS on improving movement-related brain function in stroke. 

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2. Regional Vessel Density Reduction in the Macula and Optic Nerve Head of Patients With Pre-Perimetric Primary Open Angle Glaucoma

   https://doi.org/10.1097/IJG.0000000000002310  

   Verticchio_Vercellin, Alice; Siesky, Brent; Antman, Gal; Oddone, Francesco; Chang, Michael; Eckert, George; Arciero, Julia; Kellner, Rebecca L; Fry, Brendan; Coleman-Belin, Janet; et al (January 2023, Journal of Glaucoma)

   Précis:Capillary and neuronal tissue loss occur both globally and with regional specificity in pre-perimetric glaucoma patients at the level of the optic nerve and macula, with perifovea regions affected earlier than parafovea areas. Purpose:To investigate optic nerve head (ONH) and macular vessel densities (VD) and structural parameters assessed by optical coherence tomography angiography in pre-perimetric open angle glaucoma (ppOAG) patients and healthy controls. Materials and Methods:In all, 113 healthy and 79 ppOAG patients underwent global and regional (hemispheric/quadrants) assessments of retinal, ONH, and macular vascularity and structure, including ONH parameters, retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thickness. Comparisons between outcomes in ppOAG and controls were adjusted for age, sex, race, BMI, diabetes, and hypertension, withP<0.05 considered statistically significant. Results:In ppOAG compared with healthy controls: RNFL thicknesses were statistically significantly lower for all hemispheres, quadrants, and sectors (P<0.001–0.041); whole image peripapillary all and small blood vessels VD were statistically significantly lower for all the quadrants (P<0.001–0.002), except for the peripapillary small vessels in the temporal quadrant (ppOAG: 49.66 (8.40), healthy: 53.45 (4.04);P=0.843); GCC and inner and full macular thicknesses in the parafoveal and perifoveal regions were significantly lower in all the quadrants (P=0.000–P=0.033); several macular VD were significantly lower (P=0.006–0.034), with the exceptions of macular center, parafoveal superior and inferior quadrant, and perifoveal superior quadrant (P>0.05). Conclusions:In ppOAG patients, VD biomarkers in both the macula and ONH, alongside RNFL, GCC, and macular thickness, were significantly reduced before detectable visual field loss with regional specificity. The most significant VD reduction detected was in the peripheric (perifovea) regions. Macular and ONH decrease in VD may serve as early biomarkers of glaucomatous disease. 

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3. Activation of Superficial and Deep Finger Flexors through Transcutaneous Nerve Stimulation

   https://doi.org/10.1109/JBHI.2020.3041669  

   Shin, Henry; Hawari, Marwan A.; Hu, Xiaogang (October 2020, IEEE Journal of Biomedical and Health Informatics)

   null (Ed.)

   Objective: Functional electrical stimulation (FES) is a common technique to elicit muscle contraction and help improve muscle strength. Traditional FES over the muscle belly typically only activates superficial muscle regions. In the case of hand FES, this prevents the activation of the deeper flexor muscles which control the distal finger joints. Here, we evaluated whether an alternative transcutaneous nerve-bundle stimulation approach can activate both superficial and deep extrinsic finger flexors using a high-density stimulation grid. Methods: Transverse ultrasound of the forearm muscles was used to obtain cross-sectional images of the underlying finger flexors during stimulated finger flexions and kinematically-matched voluntary motions. Finger kinematics were recorded, and an image registration method was used to capture the large deformation of the muscle regions during each flexion. This deformation was used as a surrogate measure of the contraction of muscle tissue, and the regions of expanding tissue can identify activated muscles. Results: The nerve-bundle stimulation elicited contractions in the superficial and deep finger flexors. Both separate and concurrent activation of these two muscles were observed. Joint kinematics of the fingers also matched the expected regions of muscle contractions. Conclusions: Our results showed that the nerve-bundle stimulation technique can activate the deep extrinsic finger flexors, which are typically not accessible via traditional surface FES. Significance: Our nerve-bundle stimulation method enables us to produce the full range of motion of different joints necessary for various functional grasps, which could benefit future neuroprosthetic applications. 

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4. Neighborhood Perceptions Are Associated With Intrinsic Amygdala Activity and Resting-State Connectivity With Salience Network Nodes Among Older Adults

   https://doi.org/10.1097/PSY.0000000000001272  

   Ortiz-Whittingham, Lola R; Zhan, Liang; Ortiz-Chaparro, Erika N; Baumer, Yvonne; Zenk, Shannon; Lamar, Melissa; Powell-Wiley, Tiffany M (January 2024, Psychosomatic Medicine)

   ABSTRACT ObjectiveNeighborhood perceptions are associated with physical and mental health outcomes; however, the biological associates of this relationship remain to be fully understood. Here, we evaluate the relationship between neighborhood perceptions and amygdala activity and connectivity with salience network (i.e., insula, anterior cingulate, thalamus) nodes. MethodsForty-eight older adults (mean age = 68 [7] years, 52% female, 47% non-Hispanic Black, 2% Hispanic) without dementia or depression completed the Perceptions of Neighborhood Environment Scale. Lower scores indicated less favorable perceptions of aesthetic quality, walking environment, availability of healthy food, safety, violence (i.e., more perceived violence), social cohesion, and participation in activities with neighbors. Participants separately underwent resting-state functional magnetic resonance imaging. ResultsLess favorable perceived safety (β= −0.33,p_FDR= .04) and participation in activities with neighbors (β= −0.35,p_FDR= .02) were associated with higher left amygdala activity, independent of covariates including psychosocial factors. Less favorable safety perceptions were also associated with enhanced left amygdala functional connectivity with the bilateral insular cortices and the left anterior insula (β= −0.34,p_FDR= .04). Less favorable perceived social cohesion was associated with enhanced left amygdala functional connectivity with the right thalamus (β =−0.42,p_FDR= .04), and less favorable perceptions about healthy food availability were associated with enhanced left amygdala functional connectivity with the bilateral anterior insula (right:β= −0.39,p_FDR= .04; left:β= −0.42,p_FDR= .02) and anterior cingulate gyrus (β= −0.37,p_FDR= .04). ConclusionsTaken together, our findings document relationships between select neighborhood perceptions and amygdala activity as well as connectivity with salience network nodes; if confirmed, targeted community-level interventions and existing community strengths may promote brain-behavior relationships. 

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5. Cold Storage Followed by Transplantation Induces Immunoproteasome in Rat Kidney Allografts: Inhibition of Immunoproteasome Does Not Improve Function

   https://doi.org/10.34067/KID.0000000000000368  

   Bhattarai, Dinesh; Lee, Seong-ok; Joshi, Neelam; Jun, Se-Ran; Lo, Sorena; Jiang, Li; Gokden, Neriman; Parajuli, Nirmala (February 2024, Kidney360)

   Background:It is a major clinical challenge to ensure the long-term function of transplanted kidneys. Specifically, the injury associated with cold storage of kidneys compromises the long-term function of the grafts after transplantation. Therefore, the molecular mechanisms underlying cold-storage–related kidney injury are attractive therapeutic targets to prevent injury and improve long-term graft function. Previously, we found that constitutive proteasome function was compromised in rat kidneys after cold storage followed by transplantation. Here, we evaluated the role of the immunoproteasome (iproteasome), a proteasome variant, during cold storage (CS) followed by transplantation. Methods:Established in vivo rat kidney transplant model with or without CS containing vehicle or iproteasome inhibitor (ONX 0914) was used in this study. Theiproteasome function was performed using rat kidney homogenates and fluorescent-based peptide substrate specific to β5i subunit. Western blotting and quantitative RT-PCR were used to assess the subunit expression/level of theiproteasome (β5i) subunit. Results:We demonstrated a decrease in the abundance of the β5i subunit of theiproteasome in kidneys during CS, but β5i levels increased in kidneys after CS and transplant. Despite the increase in β5i levels and its peptidase activity within kidneys, inhibiting β5i during CS did not improve graft function after transplantation. Summary:These results suggest that the pharmacological inhibition of immunoproteasome function during CS does not improve graft function or outcome. In light of these findings, future studies targeting immunoproteasomes during both CS and transplantation may define the role of immunoproteasomes on short- and long-term kidney transplant outcomes. 

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