214 research outputs found
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The neurological underpinnings of cluttering: Some initial findings
Background
Cluttering is a fluency disorder characterised by overly rapid or jerky speech patterns that compromise intelligibility. The neural correlates of cluttering are unknown but theoretical accounts implicate the basal ganglia and medial prefrontal cortex. Dysfunction in these brain areas would be consistent with difficulties in selection and control of speech motor programs that are characteristic of speech disfluencies in cluttering. There is a surprising lack of investigation into this disorder using modern imaging techniques. Here, we used functional MRI to investigate the neural correlates of cluttering.
Method
We scanned 17 adults who clutter and 17 normally fluent control speakers matched for age and sex. Brain activity was recorded using sparse-sampling functional MRI while participants viewed scenes and either (i) produced overt speech describing the scene or (ii) read out loud a sentence provided that described the scene. Speech was recorded and analysed off line. Differences in brain activity for each condition compared to a silent resting baseline and between conditions were analysed for each group separately (cluster-forming threshold Z > 3.1, extent p 30 voxels, uncorrected).
Results
In both conditions, the patterns of activation in adults who clutter and control speakers were strikingly similar, particularly at the cortical level. Direct group comparisons revealed greater activity in adults who clutter compared to control speakers in the lateral premotor cortex bilaterally and, as predicted, on the medial surface (pre-supplementary motor area). Subcortically, adults who clutter showed greater activity than control speakers in the basal ganglia. Specifically, the caudate nucleus and putamen were overactive in adults who clutter for the comparison of picture description with sentence reading. In addition, adults who clutter had reduced activity relative to control speakers in the lateral anterior cerebellum bilaterally.
Eleven of the 17 adults who clutter also stuttered. This comorbid diagnosis of stuttering was found to contribute to the abnormal overactivity seen in the group of adults who clutter in the right ventral premotor cortex and right anterior cingulate cortex. In the remaining areas of abnormal activity seen in adults who clutter compared to controls, the subgroup who clutter and stutter did not differ from the subgroup who clutter but do not stutter.
Conclusions
Our findings were in good agreement with theoretical predictions regarding the neural correlates of cluttering. We found evidence for abnormal function in the basal ganglia and their cortical output target, the medial prefrontal cortex. The findings are discussed in relation to models of cluttering that point to problems with motor control of speech
Optimizing fire station locations for the Istanbul metropolitan municipality
Copyright @ 2013 INFORMSThe Istanbul Metropolitan Municipality (IMM) seeks to determine locations for additional fire stations to build in Istanbul; its objective is to make residences and historic sites reachable by emergency vehicles within five minutes of a fire station’s receipt of a service request. In this paper, we discuss our development of a mathematical model to aid IMM in determining these locations by using data retrieved from its fire incident records. We use a geographic information system to implement the model on Istanbul’s road network, and solve two location models—set-covering and maximal-covering—as what-if scenarios. We discuss 10 scenarios, including the situation that existed when we initiated the project and the scenario that IMM implemented. The scenario implemented increases the city’s fire station coverage from 58.6 percent to 85.9 percent, based on a five-minute response time, with an implementation plan that spans three years
Woodfordian Glacial History of the Champlain Lowland, Burlington to Brandon, Vermont
Guidebook for field trips in Vermont: 64th annual meeting October 13, 14, 15, 1972 Burlington, Vermont: Trip G-
The Rocky Mountain Arsenal: Groundwater Contamination and Clean-Up Activities
26 pages (includes illustrations and map)
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Atomic Energy Commission Reports
Gamma scintillation monitor Model 3 is designed to continuously monitor and record the gamma activity of a process solution
Disrupted white matter in language and motor tracts in developmental stuttering
White matter tractsc onnecting areas involved in speech and motor control were examined using diffusion-tensor imagingingin a sample of peoplewhostutter (n=29) who were heterogeneous with respect to age, sex, handedness and stuttering severity. The goals were to replicate previous findings in developmental stuttering and to extend ourknowledge by evaluating the relationship between white matter differences in people who stutter and factors such as age, sex, handedness and stuttering severity. We replicated previous findings that showed reduced integrity in white matter underlying ventral premotorcortex,
cerebral peduncles and posteriorcorpus callosum in people who stutter, relative to controls. Tractography analysis additionally revealed significantly reduced white matter integrity in the arcuate fasciculus bilaterally and the left corticospinal tract and significantly reduced connectivity within theleft corticobulbar tract in people who stutter. Region-of-interest analyses revealed
reduced white matter integrity in people whostutter in the three pairs ocerebellar peduncles thatcarry the afferent and efferent fibers of the cerebellum. Within thegroup of people who stutter, the higher the stuttering severity index, the lower the white matter integrity in the leftangular gyrus but the greater the white matter connectivity in theleft corticobulbartract. Also,in people who stutter, handedness and age predicted the integrity of the corticospinal tract and peduncles, respectively. Further studies are needed to determine which of these white matter differences relate to the neural
basis of stuttering and which reflect experience-dependent plasticity
Hunter Motivations and Use of Wild Pigs in Texas, USA
Wild pigs (Sus scrofa) are a widespread exotic, invasive species that pose ecological, agricultural, and human health risks in their invaded range. Wildlife managers must manage wild pig abundance and range expansion to mitigate these risks. The diversity of stakeholders involved in the issue of wild pig management complicates efforts to manage the species, and, to be successful, wildlife professionals must consider the human dimensions associated with wild pig management. The prevalence of privately owned lands in Texas, USA necessitates cooperation to enact effective management policies. In this study, we investigate the impact of hunter motivations on wild pig harvest quantity. Motivations driving wild pig hunting are diverse. While the majority of wild pig hunters in Texas are motivated by trophy value, meat-motivated hunters harvest more wild pigs per day afield. Wildlife managers should develop plans that include various management techniques to control wild pig population growth and damage. Education and outreach will continue to be important for involving private landowners in effective wild pig management
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No evidence of altered language laterality in people who stutter across different brain imaging studies of speech and language
A long-standing neurobiological explanation of stuttering is the incomplete cerebral dominance theory, which refers to competition between two hemispheres for ‘dominance’ over handedness and speech, causing altered language lateralization. Renewed interest in these ideas came from brain imaging findings in people who stutter of increased activity in the right hemisphere during speech production or of shifts in activity from right to left when fluency increased. Here, we revisited this theory using functional MRI data from children and adults who stutter, and typically fluent speakers (119 participants in total) during four different speech and language tasks: overt sentence reading, overt picture description, covert sentence reading and covert auditory naming. Laterality indices were calculated for the frontal and temporal lobes using the laterality index toolbox running in Statistical Parametric Mapping. We also repeated the analyses with more specific language regions, namely the pars opercularis (Brodmann area 44) and pars triangularis (Brodmann area 45). Laterality indices in people who stutter and typically fluent speakers did not differ, and Bayesian analyses provided moderate to anecdotal levels of support for the null hypothesis (i.e. no differences in laterality in people who stutter compared with typically fluent speakers). The proportions of the people who stutter and typically fluent speakers who were left lateralized or had atypical rightward or bilateral lateralization did not differ. We found no support for the theory that language laterality is reduced or differs in people who stutter compared with typically fluent speakers
A Profile of Wild Pig Hunters in Texas, USA
Wild pigs (Sus scrofa) are a widespread exotic, invasive species that poses ecological, agricultural, and human health risks in invaded areas. Wildlife managers often manage wild pig abundance and expansion to mitigate these risks. The diversity of stakeholders involved in the issue of wild pig management complicates efforts to manage the species, and, to be successful, wildlife professionals should consider the human dimensions associated with wild pig management. The prevalence of privately owned lands in Texas, USA necessitates cooperation to enact effective management policies. In this study, we investigate the factors that affect a hunter’s likelihood to participate in wild pig hunting. Multiple factors affect participation in wild pig hunting activities. We found that participation in other types of big game hunting increased the likelihood of participation in wild pig hunting and that wild pig hunting does not deter individuals from participating in other types of hunting activities. Additionally, hunters’ attitudes toward wild pigs are important in determining the likelihood of participation in wild pig hunting. Finally, our results suggest that hunters are largely uninformed about wild pigs and do not hold the same perceptions, values, or tolerance levels of the species. The diversity of preferences among wild pig hunters necessitates that wildlife managers consider the desires of the public as well as natural resource needs in creating socially acceptable management plans for the species
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