944 research outputs found
Lesion mapping in acute stroke aphasia and its implications for recovery
Get PDFItem does not contain fulltextPatients with stroke offer a unique window into understanding human brain function. Mapping stroke lesions poses several challenges due to the complexity of the lesion anatomy and the mechanisms causing local and remote disruption on brain networks. In this prospective longitudinal study, we compare standard and advanced approaches to white matter lesion mapping applied to acute stroke patients with aphasia. Eighteen patients with acute left hemisphere stroke were recruited and scanned within two weeks from symptom onset. Aphasia assessment was performed at baseline and six-month follow-up. Structural and diffusion MRI contrasts indicated an area of maximum overlap in the anterior external/extreme capsule with diffusion images showing a larger overlap extending into posterior perisylvian regions. Anatomical predictors of recovery included damage to ipsilesional tracts (as shown by both structural and diffusion images) and contralesional tracts (as shown by diffusion images only). These findings indicate converging results from structural and diffusion lesion mapping methods but also clear differences between the two approaches in their ability to identify predictors of recovery outside the lesioned regions.13 p
Making a market for Miscanthus: Can new contract designs solve the biofuel investment hold-up problem?
Get PDFWe present designs for optimal contracts to solve the investment hold-up problem for perennial crops for the biofuel industry. A fixed-price contract is ex-ante efficient but renegotiation-proof for a limited range of discount parameters. A perfectly- indexed contract is both renegotiation-proof and ex-post efficient. Provided long-run land prices are stationary, the expected cost for both contracts converges to the long-run expected price of land for a risk-neutral farmer.Biofuels, Miscanthus, contract theory, industrial organization, renegotiation-proof contract, Marketing,
D-PLACE aggregated dataset
No full text<p>Cite the source of the dataset as:</p>
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<p>Kathryn R. Kirby, Russell D. Gray, Simon J. Greenhill, Fiona M. Jordan, Stephanie Gomes-Ng, Hans-Jörg Bibiko, Damián E. Blasi, Carlos A. Botero, Claire Bowern, Carol R. Ember, Dan Leehr, Bobbi S. Low, Joe McCarter, William Divale, and Michael C. Gavin. (2016). D-PLACE: A Global Database of Cultural, Linguistic and Environmental Diversity. PLoS ONE, 11(7): e0158391. doi:10.1371/journal.pone.0158391.</p>
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Clustering of children's activity behaviour: the use of self-report versus direct measures
Get PDFAbstract While we concur with the objectives of the recent International Journal of Behavioural Nutrition and Physical Activity paper published by Jago and colleagues titled "Physical activity and sedentary behaviour typologies of 10-11 year olds", we feel that the results as currently presented do not support their conclusions. Though the authors created groups of children with dramatically different patterns of self-reported physical activity and sedentary behaviour, an inspection of the objectively measured accelerometry data shows little difference between the groups. Further, in at least one instance the difference between groups was of the opposite direction when using objective measures, as opposed to the self-report measures used in the published analysis. Thus, we caution the authors from making conclusions based on their self-report data, and propose that they re-analyze their data using their objectively measured data instead.</p
Utilization of Occupational Therapy by Older Healthy Adults at Risk for Falls Is Low
No full textAbstract
Date Presented 3/31/2017
A retrospective content analysis on physicians’ dictations for 50 healthy older adults visiting an ambulatory orthopedic spine clinic revealed that physicians may not be screening for executive functioning impairment or referring to occupational therapy for fall prevention.
Primary Author and Speaker: Stephanie Foo
Additional Authors and Speakers: M. J. Mulcahey, Catherine Piersol</jats:p
D-PLACE/dplace-data: D-PLACE – the Database of Places, Language, Culture and Environment
No full text<p>Kathryn R. Kirby, Russell D. Gray, Simon J. Greenhill, Fiona M. Jordan, Stephanie Gomes-Ng, Hans-Jörg Bibiko, … Michael C. Gavin. (2016). D-PLACE – the Database of Places, Language, Culture and Environment v1.0 [Data set].
<a href="https://doi.org/10.5281/zenodo.439199"></a></p>
The anatomy of fronto-occipital connections from early blunt dissections to contemporary tractography
Get PDFThe occipital and frontal lobes are anatomically distant yet functionally highly integrated to generate some of the most complex behaviour. A series of long associative fibres, such as the fronto-occipital networks, mediate this integration via rapid feed-forward propagation of visual input to anterior frontal regions and direct top–down modulation of early visual processing.Despite the vast number of anatomical investigations a general consensus on the anatomy of fronto-occipital connections is not forthcoming. For example, in the monkey the existence of a human equivalent of the ‘inferior fronto-occipital fasciculus’ (iFOF) has not been demonstrated. Conversely, a ‘superior fronto-occipital fasciculus’ (sFOF), also referred to as ‘subcallosal bundle’ by some authors, is reported in monkey axonal tracing studies but not in human dissections.In this study our aim is twofold. First, we use diffusion tractography to delineate the in vivo anatomy of the sFOF and the iFOF in 30 healthy subjects and three acallosal brains. Second, we provide a comprehensive review of the post-mortem and neuroimaging studies of the fronto-occipital connections published over the last two centuries, together with the first integral translation of Onufrowicz's original description of a human fronto-occipital fasciculus (1887) and Muratoff's report of the ‘subcallosal bundle’ in animals (1893).Our tractography dissections suggest that in the human brain (i) the iFOF is a bilateral association pathway connecting ventro-medial occipital cortex to orbital and polar frontal cortex, (ii) the sFOF overlaps with branches of the superior longitudinal fasciculus (SLF) and probably represents an ‘occipital extension’ of the SLF, (iii) the subcallosal bundle of Muratoff is probably a complex tract encompassing ascending thalamo-frontal and descending fronto-caudate connections and is therefore a projection rather than an associative tract.In conclusion, our experimental findings and review of the literature suggest that a ventral pathway in humans, namely the iFOF, mediates a direct communication between occipital and frontal lobes. Whether the iFOF represents a unique human pathway awaits further ad hoc investigations in animals
White matter variability, cognition, and disorders: a systematic review
Get PDFInter-individual differences can inform treatment procedures and - if accounted for - can significantly improve patient outcomes. However, when studying brain anatomy, these inter-individual variations are largely unaccounted for, despite reports of differences in gross anatomical features, cross-sectional and connectional anatomy. Brain connections are essential to mediate brain functional organisation and, when severed, cause functional impairments or complete loss of function. Hence the study of cerebral white matter may be an ideal compromise to capture inter-individual variability in structure and function. Here we reviewed the wealth of studies that associate functions and clinical symptoms with individual tracts using diffusion tractography. Our systematic review indicates that tractography has proven to be a sensitive method in neurology, psychiatry and healthy populations to identify variability and its functional correlates. However, the literature may be biased, as we identified that the most commonly reported tracts are not necessarily those with the highest sensitivity to cognitive functions and pathologies. Finally, we demonstrate that tracts, as we define them, are not usually correlated with only one, but rather multiple cognitive domains or pathologies. While our systematic review identified some methodological caveats, it also suggests that tract-function correlations might be a promising biomarker for precision medicine as it characterises variations in brain anatomy, differences in functional organisation and predict resilience or recovery in patients
Epigenetic regulation of neuroinflammation in the aged mouse brain
Get PDFAs the average lifespan continues to rise, there is a significant increase in the number of people suffering from age-related chronic inflammatory diseases such as autoimmune disorders, cancer, and neurodegenerative diseases. Therefore, there is a greater need to understand the factors that contribute to quality of life in the elderly. Growing evidence indicates that the immune system plays a critical role in regulating the progression of brain aging. However, an important question remains of whether inflammatory pathways become hyperactivated with age, or whether deficient immune responses, which fail to cope with age-related deterioration, may contribute to disease.
Microglia, the resident immune cells of the brain, are key players in regulating neuroinflammation. They function as the primary immune surveillance, provide the first host defense by secreting factors such as cytokines and chemokines, and carry out specific central nervous system functions such as synaptic pruning and secretion of neurotrophic factors. Of note, microglia are also long-lived within the brain and have a limited turnover, suggesting that they are a likely target for epigenetic regulation.
In order to determine possible causes and targets for interventions to promote healthy aging, the current dissertation explored the role of epigenetic regulation in microglia as well as potential pharmacological and dietary interventions that could be beneficial for chronic age-related neuroinflammation. This dissertation was divided into three major sections. In Chapter 2, we determined that aged mice had decreased methylation of the Il1b gene promoter in primary microglia basally or following systemic lipopolysaccharide (LPS) that is associated with increased Il1b mRNA, intracellular IL-1β production, as well as prolonged sickness behavior. We also determined changes in epigenetic regulator gene expression with both age and LPS. Furthermore, we found that inhibiting DNA methylation increased Il1b gene expression and decreased DNA methylation of BV2 and primary microglial cells similar to microglia from aged mice. In Chapter 3, we investigated whether inhibiting DNA methylation in the brain of adult mice would alter sickness behavior, DNA methylation of the Il1b promoter and expression of inflammatory genes in microglia similar to aged mice. However, we found that inhibiting DNA methylation and injecting LPS in the brain of adult mice produced faster recovery of burrowing behavior compared to mice treated only with LPS. Genes of inflammatory markers, epigenetic regulators, and the microglial sensory apparatus (i.e. the sensome) were also differentially expressed by inhibiting DNA methylation alone or in combination with LPS. Lastly, DNA methylation of Il1b proximal promoter was changed by inhibiting DNA methylation alone or in combination with LPS, and these changes persisted 48 hours after LPS treatment. In Chapter 4, we investigated whether injections of butyrate or increases in butyrate through a highly fermentable diet could affect microglial activation, and specifically microglial activation in aging. We determined that gene expression of inflammatory markers, epigenetic regulators, and the microglial sensome were altered by both diet and age, in that aged animals had a more anti-inflammatory profile on the high fiber diet.
In summary, the studies outlined in this dissertation comprise evidence that epigenetic changes are present in aging microglia, and that pharmacological agents and nutrients that act as epigenetic modifiers can alter microglial phenotypes. This could lead to the development of therapeutic interventions aimed at specifically promoting beneficial microglia reactivity associated with infection, which may be important for fostering better recovery from sickness and reducing cognitive deficits and age-associated disease in the elderly.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2020-05-01The student, Stephanie Matt, accepted the attached license on 2018-03-04 at 16:43.The student, Stephanie Matt, submitted this Dissertation for approval on 2018-03-13 at 14:45.This Dissertation was approved for publication on 2018-03-16 at 16:52.DSpace SAF Submission Ingestion Package generated from Vireo submission #12054 on 2018-08-31 at 17:17:13Made available in DSpace on 2018-09-04T20:33:49Z (GMT). No. of bitstreams: 3
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Lesion-Symptom Mapping: From Single Cases to the Human Disconnectome
Get PDFLesion symptom mapping has revolutionized our understanding of the functioning of the human brain. Associating damaged voxels in the brain with loss of function has created a map of the brain that identifies critical areas. While these methods have significantly advanced our understanding, recent improvements have identified the need for multivariate and multimodal methods to map hidden lesions and damage to white matter networks beyond the lesion voxels. This article reviews the evolution of lesion-symptom mapping from single case studies to the human disconnectome
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