Understanding the role of the primary somatosensory cortex: Opportunities for rehabilitation.

Emerging evidence indicates impairments in somatosensory function may be a major contributor to motor dysfunction associated with neurologic injury or disorders. However, the neuroanatomical substrates underlying the connection between aberrant sensory input and ineffective motor output are still under investigation. The primary somatosensory cortex (S1) plays a critical role in processing afferent somatosensory input and contributes to the integration of sensory and motor signals necessary for skilled movement. Neuroimaging and neurostimulation approaches provide unique opportunities to non-invasively study S1 structure and function including connectivity with other cortical regions. These research techniques have begun to illuminate casual contributions of abnormal S1 activity and connectivity to motor dysfunction and poorer recovery of motor function in neurologic patient populations. This review synthesizes recent evidence illustrating the role of S1 in motor control, motor learning and functional recovery with an emphasis on how information from these investigations may be exploited to inform stroke rehabilitation to reduce motor dysfunction and improve therapeutic outcomes

A large, curated, open-source stroke neuroimaging dataset to improve lesion segmentation algorithms

Accurate lesion segmentation is critical in stroke rehabilitation research for the quantifcation of lesion burden and accurate image processing. Current automated lesion segmentation methods for T1-weighted (T1w) MRIs, commonly used in stroke research, lack accuracy and reliability. Manual segmentation remains the gold standard, but it is time-consuming, subjective, and requires neuroanatomical expertise. We previously released an open-source dataset of stroke T1w MRIs and manually-segmented lesion masks (ATLAS v1.2, N=304) to encourage the development of better algorithms. However, many methods developed with ATLAS v1.2 report low accuracy, are not publicly accessible or are improperly validated, limiting their utility to the feld. Here we present ATLAS v2.0 (N=1271), a larger dataset of T1w MRIs and manually segmented lesion masks that includes training (n=655), test (hidden masks, n=300), and generalizability (hidden MRIs and masks, n=316) datasets. Algorithm development using this larger sample should lead to more robust solutions; the hidden datasets allow for unbiased performance evaluation via segmentation challenges. We anticipate that ATLAS v2.0 will lead to improved algorithms, facilitating large-scale stroke research.Sook-Lei Liew ... Brenton G. Hordacre ... et al

Establishing between-session reliability of TMS-conditioned soleus H-reflexes

Ekonomski razvoj je neostvariv i nezamisliv bez inovacija i bez poduzetništva. Kako su poduzeća jedan od glavnih pokretača gospodarstva, velikim otvaranjem radnih mjesta te rastom proizvodnje i potrošnje, može se zaključiti da inovacije preko poduzetništva pokreću nacionalno, ali uvelike i svjetsko gospodarstvo. S obzirom na gospodarske krize i loše situacije kao što su uvelike propadanje poduzeća, u Republici Hrvatskoj zadnjih godina dolazi do razvoja poduzetništva, posebice onih manjih za koje je država osigurala posebne potporne institucije, poduzetničke inkubatore, poduzetničke centre poduzetnički centri koji se razvijaju u svim županijama,gradovima i općinama diljem Hrvatske. Ovisno o broju poduzetnika na određenom području kojima su takve usluge potrebne. Također postoje razni natječaji koji sve više pozivaju ljude da postanu poduzetnici i što više pridonesu razvoju zemlje. Važno je napomenuti da banke nude razne kredite za pomoć poduzetnicima, Krediti se izdaju u kunskoj vrijednosti i mogu iznositi od 80.000.00 do 8.000.000.00. Da poduzetnici koriste ove pogodnosti donose brojke u nastavku rada.Economic development is impossible and unthinkable without innovation and without entrepreneurship. As enterprises are one of the main drivers of the economy, with great job creation and growth in production and consumption, it can be concluded that innovation through entrepreneurship drives the national, but to a large extent, the world economy. In view of economic crises and bad situations such as the large-scale decay of enterprises, the Republic of Croatia has been developing entrepreneurship in recent years, especially those smaller ones for which the state has provided special support institutions, entrepreneurial incubators, entrepreneurial centers. all counties, cities and municipalities throughout Croatia. Depending on the number of entrepreneurs in a particular area who need such services There are also various competitions that increasingly invite people to become entrepreneurs and contribute more to the development of the country. It is important to note that banks offer various loans to help entrepreneurs, Loans are issued in kuna value and can range from 80,000.00 to 8,000,000.00. For entrepreneurs to use these benefits, they bring in the numbers below

Comparing a diffusion tensor and non-tensor approach to white matter fiber tractography in chronic stroke

Diffusion tensor imaging (DTI)-based tractography has been used to demonstrate functionally relevant differences in white matter pathway status after stroke. However, it is now known that the tensor model is insensitive to the complex fiber architectures found in the vast majority of voxels in the human brain. The inability to resolve intra-voxel fiber orientations may have important implications for the utility of standard DTI-based tract reconstruction methods. Intra-voxel fiber orientations can now be identified using novel, tensor-free approaches. Constrained spherical deconvolution (CSD) is one approach to characterize intra-voxel diffusion behavior. In the current study, we performed DTI- and CSD-based tract reconstruction of the corticospinal tract (CST) and corpus callosum (CC) to test the hypothesis that characterization of complex fiber orientations may improve the robustness of fiber tract reconstruction and increase the sensitivity to identify functionally relevant white matter abnormalities in individuals with chronic stroke. Diffusion weighted magnetic resonance imaging was performed in 27 chronic post-stroke participants and 12 healthy controls. Transcallosal pathways and the CST bilaterally were reconstructed using DTI- and CSD-based tractography. Mean fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusivity (AD), and radial diffusivity (RD) were calculated across the tracts of interest. The total number and volume of reconstructed tracts was also determined. Diffusion measures were compared between groups (Stroke, Control) and methods (CSD, DTI). The relationship between post-stroke motor behavior and diffusion measures was evaluated. Overall, CSD methods identified more tracts than the DTI-based approach for both CC and CST pathways. Mean FA, ADC, and RD differed between DTI and CSD for CC-mediated tracts. In these tracts, we discovered a difference in FA for the CC between stroke and healthy control groups using CSD but not DTI. CSD identified ipsilesional CST pathways in 9 stroke participants who did not have tracts identified with DTI. Additionally, CSD differentiated between stroke ipsilesional and healthy control non-dominant CST for several measures (number of tracts, tract volume, FA, ADC, and RD) whereas DTI only detected group differences for number of tracts. In the stroke group, motor behavior correlated with fewer diffusion metrics derived from the DTI as compared to CSD-reconstructed ipsilesional CST and CC. CSD is superior to DTI-based tractography in detecting differences in diffusion characteristics between the nondominant healthy control and ipsilesional CST. CSD measures of microstructure tissue properties related to more motor outcomes than DTI measures did. Our results suggest the potential utility and functional relevance of characterizing complex fiber organization using tensor-free diffusion modeling approaches to investigate white matter pathways in the brain after stroke

Chronic Stroke Sensorimotor Impairment Is Related to Smaller Hippocampal Volumes: An ENIGMA Analysis

BACKGROUND: Persistent sensorimotor impairments after stroke can negatively impact quality of life. The hippocampus is vulnerable to poststroke secondary degeneration and is involved in sensorimotor behavior but has not been widely studied within the context of poststroke upper-limb sensorimotor impairment. We investigated associations between non-lesioned hippocampal volume and upper limb sensorimotor impairment in people with chronic stroke, hypothesizing that smaller ipsilesional hippocampal volumes would be associated with greater sensorimotor impairment. METHODS AND RESULTS: Cross-sectional T1-weighted magnetic resonance images of the brain were pooled from 357 participants with chronic stroke from 18 research cohorts of the ENIGMA (Enhancing NeuoImaging Genetics through Meta-Analysis) Stroke Recovery Working Group. Sensorimotor impairment was estimated from the FMA-UE (Fugl-Meyer Assessment of Upper Extremity). Robust mixed-effects linear models were used to test associations between poststroke sensorimotor impairment and hippocampal volumes (ipsilesional and contralesional separately; Bonferroni-corrected, P<0.025), controlling for age, sex, lesion volume, and lesioned hemisphere. In exploratory analyses, we tested for a sensorimotor impairment and sex interaction and relationships between lesion volume, sensorimotor damage, and hippocampal volume. Greater sensorimotor impairment was significantly associated with ipsilesional (P=0.005; β=0.16) but not contralesional (P=0.96; β=0.003) hippocampal volume, independent of lesion volume and other covariates (P=0.001; β=0.26). Women showed progressively worsening sensorimotor impairment with smaller ipsilesional (P=0.008; β=−0.26) and contralesional (P=0.006; β=−0.27) hippocampal volumes compared with men. Hippocampal volume was associated with lesion size (P<0.001; β=−0.21) and extent of sensorimotor damage (P=0.003; β=−0.15). CONCLUSIONS: The present study identifies novel associations between chronic poststroke sensorimotor impairment and ipsilesional hippocampal volume that are not caused by lesion size and may be stronger in women.Artemis Zavaliangos-Petropulu, PhD, Bethany Lo, BSc, Miranda R. Donnelly, MS, Nicolas Schweighofer, PhD, Keith Lohse, PhD, PStat, Neda Jahanshad, PhD, Giuseppe Barisano, MD, Nerisa Banaj, PhD, Michael R. Borich, PhD, Lara A. Boyd, PhD, Cathrin M. Buetefisch, MD, PhD, Winston D. Byblow, PhD, Jessica M. Cassidy, PhD, Charalambos C. Charalambous, PhD, Adriana B. Conforto, PhD, Julie A. DiCarlo, MSc, Adrienne N. Dula, PhD, Natalia Egorova-Brumley, PhD, Mark R. Etherton, MD, PhD, Wuwei Feng, MD, Kelene A. Fercho, PhD, Fatemeh Geranmayeh, PhD, Colleen A. Hanlon, PhD, Kathryn S. Hayward, PhD, Brenton Hordacre, PhD, Steven A. Kautz, PhD, Mohamed Salah Khlif, PhD, Hosung Kim, PhD, Amy Kuceyeski, PhD, David J. Lin, MD, Jingchun Liu, MD, Martin Lotze, MD, Bradley J. MacIntosh, PhD, John L. Margetis, OTD, Feroze B. Mohamed, PhD, Fabrizio Piras, PhD, Ander Ramos-Murguialday, PhD, Kate P. Revill, PhD, Pamela S. Roberts, PhD, Andrew D. Robertson, PhD, Heidi M. Schambra, MD, Na Jin Seo, PhD, Mark S. Shiroishi, MD, Cathy M. Stinear, PhD, Surjo R. Soekadar, MD, Gianfranco Spalletta, MD, PhD, Myriam Taga, PhD, Wai Kwong Tang, MD, Gregory T. Thielman, EdD, Daniela Vecchio, PhD, Nick S. Ward, MD, Lars T. Westlye, PhD, Emilio Werden, PhD, Carolee Winstein, PhD, PT, George F. Wittenberg, MD, PhD, Steven L. Wolf, PhD, Kristin A. Wong, MD, Chunshui Yu, MD, Amy Brodtmann, MD, PhD, Steven C. Cramer, MD, Paul M. Thompson, PhD, Sook-Lei Liew, PhD, OTR,

Association of Brain Age, Lesion Volume, and Functional Outcome in Patients With Stroke

BACKGROUND AND OBJECTIVES: Functional outcomes after stroke are strongly related to focal injury measures. However, the role of global brain health is less clear. Here, we examined the impact of brain age, a measure of neurobiological aging derived from whole brain structural neuroimaging, on post-stroke outcomes, with a focus on sensorimotor performance. We hypothesized that more lesion damage would result in older brain age, which would in turn be associated with poorer outcomes. Related, we expected that brain age would mediate the relationship between lesion damage and outcomes. Finally, we hypothesized that structural brain resilience, which we define in the context of stroke as younger brain age given matched lesion damage, would differentiate people with good versus poor outcomes. METHODS: We conducted a cross-sectional observational study using a multi-site dataset of 3D brain structural MRIs and clinical measures from ENIGMA Stroke Recovery. Brain age was calculated from 77 neuroanatomical features using a ridge regression model trained and validated on 4,314 healthy controls. We performed a three-step mediation analysis with robust mixed-effects linear regression models to examine relationships between brain age, lesion damage, and stroke outcomes. We used propensity score matching and logistic regression to examine whether brain resilience predicts good versus poor outcomes in patients with matched lesion damage. RESULTS: We examined 963 patients across 38 cohorts. Greater lesion damage was associated with older brain age (β=0.21; 95% CI 0.04,0.38, P=0.015), which in turn was associated with poorer outcomes, both in the sensorimotor domain (β=-0.28; 95% CI: -0.41,-0.15, P<0.001) and across multiple domains of function (β=-0.14; 95% CI: -0.22,-0.06, P<0.001). Brain age mediated 15% of the impact of lesion damage on sensorimotor performance (95% CI: 3%,58%, P=0.01). Greater brain resilience explained why people have better outcomes, given matched lesion damage (OR=1.04, 95% CI: 1.01,1.08, P=0.004). CONCLUSIONS: We provide evidence that younger brain age is associated with superior post-stroke outcomes and modifies the impact of focal damage. The inclusion of imaging-based assessments of brain age and brain resilience may improve the prediction of post-stroke outcomes compared to focal injury measures alone, opening new possibilities for potential therapeutic targets.Sook-Lei Liew ... Brenton Hordacre ... et al