scholarly journals Investigating the network consequences of focal brain lesions through comparisons of real and simulated lesions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuan Tao ◽  
Brenda Rapp
Keyword(s):  
Chronic Stroke ◽  
Simulation Studies ◽  
Short Term ◽  
Focal Lesions ◽  
Healthy Control ◽  
Quantitative Understanding ◽  
Network Properties ◽  
Computer Simulation Studies ◽  
Global And Local

AbstractGiven the increased interest in the functional human connectome, a number of computer simulation studies have sought to develop a better quantitative understanding of the effects of focal lesions on the brain’s functional network organization. However, there has been little work evaluating the predictions of this simulation work vis a vis real lesioned connectomes. One of the few relevant studies reported findings from real chronic focal lesions that only partially confirmed simulation predictions. We hypothesize that these discrepancies arose because although the effects of focal lesions likely consist of two components: short-term node subtraction and long-term network re-organization, previous simulation studies have primarily modeled only the short-term consequences of the subtraction of lesioned nodes and their connections. To evaluate this hypothesis, we compared network properties (modularity, participation coefficient, within-module degree) between real functional connectomes obtained from chronic stroke participants and “pseudo-lesioned” functional connectomes generated by subtracting the same sets of lesioned nodes/connections from healthy control connectomes. We found that, as we hypothesized, the network properties of real-lesioned connectomes in chronic stroke differed from those of the pseudo-lesioned connectomes which instantiated only the short-term consequences of node subtraction. Reflecting the long-term consequences of focal lesions, we found re-organization of the neurotopography of global and local hubs in the real but not the pseudo-lesioned connectomes. We conclude that the long-term network re-organization that occurs in response to focal lesions involves changes in functional connectivity within the remaining intact neural tissue that go well beyond the short-term consequences of node subtraction.

PROGRESS AND REGRESS: UNDERSTANDING COMPLEX SOCIAL MEASURES AND THEIR TRADE-OFFS

2017 ◽  
Vol 34 (2) ◽  
pp. 164-189
Author(s):  
Daniel Austin Green ◽  
Roberta Q. Herzberg
Keyword(s):  
Income Inequality ◽  
Social Values ◽  
Scientific Progress ◽  
Well Being ◽  
Moral Progress ◽  
Short Term ◽  
Economic Progress ◽  
Trade Offs ◽  
Global And Local

Abstract:What is progress and what is not progress? We can talk about progress in lots of different arenas; we will focus primarily on economic and scientific progress, but also make brief reference to cultural and moral progress. In our discussion, we want to distinguish, especially, between overall, long-term progress and narrower, shorter-term progress or regress. We will refer to these as “global” and “local” progress, respectively. Of course, one can also regress; therefore, we will also look at instances where progress, along some dimension, slows or even moves backwards. Generally, such regress is local, and often still in a context of broader, global progress. In scientific progress, for example, there are many instances of short-term progress which, if not completely discarded or disproved, are at least substantially modified or fundamentally challenged. And yet, those research paths, even when later abandoned, still contributed to the overall progress of the field. In that sense, the regress (that is, rejection or modification of previous theories) is corrected by, but not in conflict with, the overall progress. In the case of economic progress, the concept of regress usually takes on a different form in which things that aren’t advancing progress don’t necessarily stop it, but are simply retarding progress — that is, making the rate of progress less efficient. The consequence, we suggest, is that when talking about economic progress, objections to certain consequences of economic progress (for instance, income inequality — a type of regress, in our terminology) should not be cordoned off and dealt with independently, but should be incorporated into the way we think about economic progress itself — as instances of local regress within a context of global progress. We explore the effects of these different relations between progress and regress to suggest some of the challenges those seeking to broaden the standard measure, GDP, to incorporate other social values of well-being will face moving forward.

scholarly journals Impulse Inhibition Ability With Methamphetamine Dependents Varies at Different Abstinence Stages

2021 ◽  
Vol 12 ◽  
Author(s):  
Weijun Liu ◽  
Yu Tian ◽  
Xinyu Yan ◽  
Jiemin Yang
Keyword(s):  
Reaction Time ◽  
Regression Analyses ◽  
Deviant Stimulus ◽  
Short Term ◽  
Oddball Task ◽  
Healthy Control ◽  
Standard Reaction ◽  
Similar Accuracy ◽  
Inhibition Ability

Objective: The purpose of this study is to evaluate whether the impulse inhibition ability with methamphetamine dependents would vary at different abstinence stages.Methods: Sixty-three methamphetamine dependents, including 31 short-term (< 10 months) and 32 long-term (≥ 10 months) abstinence participants, were recruited for this study. In addition, 33 men were recruited as the healthy control (HC) group. All participants performed a two-choice oddball task, which is well-established to assess impulse inhibition. Accuracy for deviant trials and deviant–standard reaction time (RT) delay were computed as indexes of impulse inhibition.Results: The accuracy for deviant trials was significantly decreased in short-term abstinence subjects (90.61%) compared to HC subjects (95.42%, p < 0.01), which was coupled with a shorter RT delay reflecting greater impulsivity in the short-term group vs. the HC group (47 vs. 73 ms, p < 0.01). However, impulse inhibition was improved in the long-term group, shown by the increased accuracy for deviant trials in the long-term group compared to the short-term group (94.28 vs. 90.61%, p < 0.05) and the similar accuracy for the long-term and HC groups (p > 0.05). Further regression analyses confirmed that the abstinence duration positively predicted impulse inhibition of methamphetamine dependents, both in accuracy and RT for deviant stimulus (β = 0.294, p = 0.019; β = 0.337, p = 0.007).Conclusion: These results suggest that long-term abstinence is more effective in improving impulse inhibition with methamphetamine dependents.

scholarly journals Trends in regional morphological changes in the brain after the resolution of hypercortisolism in Cushing’s disease: a complex phenomenon, not mere partial reversibility

2021 ◽  
Author(s):  
Hong Jiang ◽  
Wen-Jie Yang ◽  
Qing-Fang Sun ◽  
Chang Liu ◽  
Liu-Guan Bian
Keyword(s):  
Cushing’S Disease ◽  
Morphological Changes ◽  
Cushing's Disease ◽  
Complex Phenomenon ◽  
Short Term ◽  
Healthy Control ◽  
Study Participants ◽  
Gray Matter Volumes ◽  
The Brain

The adverse effects of hypercortisolism on the human brain have been highlighted in previous studies of Cushing’s disease (CD). However, the relative alterations in regional hypercortisolism in the brain remain unclear. Thus, we investigated regional volumetric alterations in CD patients. We also analyzed the associations between these volumetric changes and clinical characteristics. The study participants comprised of active CD (n = 60), short-term-remitted CD (n = 28), and long-term-remitted CD (n = 32) patients as well as healthy control subjects (n = 66). Gray matter volumes (GMVs) were measured via voxel-based morphometry. The GMVs of substructures were defined using the automated anatomical labeling (AAL) atlas. Trends for partial reversibility of GMVs were found in 87 brain substructures of CD patients. However, significantly different trends, including enlarged, irreversible, and unburden trends, were observed in the rest of the brain substructures. Trends toward normalization in GMV were found in most brain substructures of CD patients. Different trends, including enlarged, irreversible, and unburden GMVs, were observed in the other subregions, such as the amygdala, thalamus, and caudate. Morphological changes in GMVs after the resolution of hypercortisolism are a complex phenomenon; the characteristics of these changes significantly differ within the brain substructures.

Validating economic and environmental sustainability of a short-term summer forage legume in dryland wheat cropping systems in south-west Queensland

2009 ◽  
Vol 49 (10) ◽  
pp. 816 ◽  
Author(s):  
D. K. Singh ◽  
R. Strahan ◽  
N. Christodoulou ◽  
S. Cawley
Keyword(s):  
Environmental Sustainability ◽  
Cropping System ◽  
Forage Yield ◽  
Environmental Benefits ◽  
Wheat Crop ◽  
Simulation Studies ◽  
Lablab Purpureus ◽  
Short Term ◽  
South West

The present study set out to test the hypothesis through field and simulation studies that the incorporation of short-term summer legumes, particularly annual legume lablab (Lablab purpureus cv. Highworth), in a fallow–wheat cropping system will improve the overall economic and environmental benefits in south-west Queensland. Replicated, large plot experiments were established at five commercial properties by using their machineries, and two smaller plot experiments were established at two intensively researched sites (Roma and St George). A detailed study on various other biennial and perennial summer forage legumes in rotation with wheat and influenced by phosphorus (P) supply (10 and 40 kg P/ha) was also carried out at the two research sites. The other legumes were lucerne (Medicago sativa), butterfly pea (Clitoria ternatea) and burgundy bean (Macroptilium bracteatum). After legumes, spring wheat (Triticum aestivum) was sown into the legume stubble. The annual lablab produced the highest forage yield, whereas germination, establishment and production of other biennial and perennial legumes were poor, particularly in the red soil at St George. At the commercial sites, only lablab–wheat rotations were experimented, with an increased supply of P in subsurface soil (20 kg P/ha). The lablab grown at the commercial sites yielded between 3 and 6 t/ha forage yield over 2–3 month periods, whereas the following wheat crop with no applied fertiliser yielded between 0.5 to 2.5 t/ha. The wheat following lablab yielded 30% less, on average, than the wheat in a fallow plot, and the profitability of wheat following lablab was slightly higher than that of the wheat following fallow because of greater costs associated with fallow management. The profitability of the lablab–wheat phase was determined after accounting for the input costs and additional costs associated with the management of fallow and in-crop herbicide applications for a fallow–wheat system. The economic and environmental benefits of forage lablab and wheat cropping were also assessed through simulations over a long-term climatic pattern by using economic (PreCAPS) and biophysical (Agricultural Production Systems Simulation, APSIM) decision support models. Analysis of the long-term rainfall pattern (70% in summer and 30% in winter) and simulation studies indicated that ~50% time a wheat crop would not be planted or would fail to produce a profitable crop (grain yield less than 1 t/ha) because of less and unreliable rainfall in winter. Whereas forage lablab in summer would produce a profitable crop, with a forage yield of more than 3 t/ha, ~90% times. Only 14 wheat crops (of 26 growing seasons, i.e. 54%) were profitable, compared with 22 forage lablab (of 25 seasons, i.e. 90%). An opportunistic double-cropping of lablab in summer and wheat in winter is also viable and profitable in 50% of the years. Simulation studies also indicated that an opportunistic lablab–wheat cropping can reduce the potential runoff + drainage by more than 40% in the Roma region, leading to improved economic and environmental benefits.

Global and local threats to coral reef functioning and existence: review and predictions

1999 ◽  
Author(s):  
Clive R. Wilkinson
Keyword(s):  
Coral Reefs ◽  
Sea Level ◽  
Sea Water ◽  
Global Climate ◽  
Short Term ◽  
Natural Factors ◽  
Carbon Dioxide Concentrations ◽  
Minimal Damage ◽  
Global And Local

Factors causing global degradation of coral reefs are examined briefly as a basis for predicting the likely consequences of increases in these factors. The earlier consensus was that widespread but localized damage from natural factors such as storms, and direct anthropogenic effects such as increased sedimentation, pollution and exploitation, posed the largest immediate threat to coral reefs. Now truly global factors associated with accelerating Global Climate Change are either damaging coral reefs or have the potential to inflict greater damage in the immediate future: e.g. increases in coral bleaching and mortality, and reductions in coral calcification due to changes in sea-water chemistry with increasing carbon dioxide concentrations. Rises in sea level will probably disrupt human communities and their cultures by making coral cays uninhabitable, whereas coral reefs will sustain minimal damage from the rise in sea level. The short-term (decades) prognosis is indeed grim, with major reductions almost certain in the extent and biodiversity of coral reefs, and severe disruptions to cultures and economies dependent on reef resources. The long-term (centuries to millennia) prognosis is more encouraging because coral reefs have remarkable resilience to severe disruption and will probably show this resilience in the future when climate changes either stabilize or reverse.

Short-term and long-term outcomes of serial robotic training for improving upper limb function in chronic stroke

2014 ◽  
Vol 37 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Patrizio Sale ◽  
Federica Bovolenta ◽  
Maurizio Agosti ◽  
Pierina Clerici ◽  
Marco Franceschini
Keyword(s):  
Upper Limb ◽  
Chronic Stroke ◽  
Long Term Outcomes ◽  
Short Term ◽  
Robotic Training ◽  
Limb Function ◽  
Upper Limb Function

Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater

2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter
Keyword(s):  
Working Memory ◽  
Rapid Serial Visual Presentation ◽  
Language Comprehension ◽  
Short Term Memory ◽  
Visual Presentation ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Use Of Knowledge

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

Ultrastructural investigations of MDL 19,660-induced effects on the canine platelet and megakaryocyte

1990 ◽  
Vol 48 (3) ◽  
pp. 374-375
Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson
Keyword(s):  
Antidepressant Drug ◽  
Beagle Dogs ◽  
Long Term Effects ◽  
Short Term ◽  
Platelet Counts ◽  
Toxicological Studies ◽  
Induced Aggregation ◽  
Internal Architecture

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.

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