Computational models of basal-ganglia pathway functions: focus on functional neuroanatomy

Over the past 15 years, computational models have had a considerable impact on basal-ganglia research. Most of these models implement multiple distinct basal-ganglia pathways and assume them to fulfill different functions. As there is now a multitude of different models, it has become complex to keep track of their various, sometimes just marginally different assumptions on pathway functions. Moreover, it has become a challenge to oversee to what extent individual assumptions are corroborated or challenged by empirical data. Focusing on computational, but also considering non-computational models, we review influential concepts of pathway functions and show to what extent they are compatible with or contradict each other. Moreover, we outline how empirical evidence favors or challenges specific model assumptions and propose experiments that allow testing assumptions against each other

Little Tots, Forget - Me - Nots : Motion Song For A Group Of Children

https://digitalcommons.library.umaine.edu/mmb-vp/5644/thumbnail.jp

Arbejdsundersøgelser og Arbejdsrationalisering.

Arbejdsundersøgelser og Arbejdsrationalisering

Om Landbrugsregnskab. Foredrag.

Om Landbrugsregnskab. Foredrag

Unintended weight loss in the elderly living at home: the aged in homecare project (Adhoc)

Objective: To describe associations between unintended weight loss (UWL) and characteristics of nutritional status. Design: A comparative cross-sectional assessment study at 11 sites in Europe. The target population was a stratified random sample of 4,455 recipients of home care (405 in each random sample from 11 urban areas) aged 65 years and older. Measurements: the Resident Assessment Instrument for Home Care, version 2.0. Epidemiological and medical characteristics of clients and service utilisation were recorded in a standardized, comparative manner. UWL was defined as information of 5% or more weight loss in the last 30 days (or 10% or more in the last 180 days). Results: The final sample consisted of 4,010 persons; 74% were female. The mean ages were 80.9 ± 7.5 years (males) and 82.8 ± 7.3 years (females). No associations were found between single diagnoses and UWL, except for cancer. Cancer patients were excluded from further analyses. Persons with a Cognitive Performance Scale value (CPS) > 3 (impaired) had increased risk of UWL (OR = 2.0) compared with those scoring < 3 (less impaired). Only in the oldest group did we find a significant association between UWL and reduction in ADL and IADL functions, comparing those who scored 3 or less with those who scored more than 3 (disabled). A binary logistic regression model explained 26% of UWL: less than one meal/day, reduced appetite, malnutrition, reduced social activity, experiencing a flare-up of a recurrent or chronic problem, and hospitalisation were important indicators. Conclusion: We recommend a regular comprehensive assessment in home care to identify clients with potential risk factors for weight loss and malnutrition, in particular those discharged from hospital, and those with physical dependency or cognitive problems. This study may provide incentives to create tailored preventive strategies

Home care needs of extremely obese elderly european women

Objective: To examine the health and needs of extremely obese women aged over 65 years receiving home care in Europe. Study design: A cross-sectional assessment study based on the Aged in Home Care (AdHOC) project recruited 2974 women aged 65 or over who were receiving home care at 11 sites in European countries. Extreme obesity was defined as ‘Obesity of such a degree as to interfere with normal activities, including respiration’. Main outcome measures: Resident Assessment Instrument for Home Care (RAI-HC version 2.0); Activity of Daily Living Scale; Instrumental Activity of Daily Living Scale; the Minimum Data Set Cognitive Performance Scale; and a health profile. Results: One hundred and twenty women (4.0%) were extremely obese. They were younger than their thinner counterparts, with a median age of 78.3 versus 83.3 years, and they more often had multiple health complaints and needed more help with mobility outside the home. The extremely obese had received home care longer than the non-extremely obese (median 28.7 versus 36.6 months). Extremely obese women also needed more help with personal care than the other group and, due to lower age, they were less cognitively impaired. Conclusions: Extreme obesity is a problem that increasingly affects home care of elderly women

Reinforcement magnitudes modulate subthalamic beta band activity in patients with Parkinson's disease

We set out to investigate whether beta oscillations in the human basal ganglia are modulated during reinforcement learning. Based on previous research, we assumed that beta activity might either reflect the magnitudes of individuals' received reinforcements (reinforcement hypothesis), their reinforcement prediction errors (dopamine hypothesis) or their tendencies to repeat versus adapt responses based upon reinforcements (status-quo hypothesis). We tested these hypotheses by recording local field potentials (LFPs) from the subthalamic nuclei of 19 Parkinson's disease patients engaged in a reinforcement-learning paradigm. We then correlated patients' reinforcement magnitudes, reinforcement prediction errors and response repetition tendencies with task-related power changes in their LFP oscillations. During feedback presentation, activity in the frequency range of 14 to 27 Hz (beta spectrum) correlated positively with reinforcement magnitudes. During responding, alpha and low beta activity (6 to 18 Hz) was negatively correlated with previous reinforcement magnitudes. Reinforcement prediction errors and response repetition tendencies did not correlate significantly with LFP oscillations. These results suggest that alpha and beta oscillations during reinforcement learning reflect patients' observed reinforcement magnitudes, rather than their reinforcement prediction errors or their tendencies to repeat versus adapt their responses, arguing both against an involvement of phasic dopamine and against applicability of the status-quo theory

Impact of a Viscous Liquid Drop

We simulate the impact of a viscous liquid drop onto a smooth dry solid surface. As in experiments, when ambient air effects are negligible, impact flattens the falling drop without producing a splash. The no-slip boundary condition at the wall produces a boundary layer inside the liquid. Later, the flattening surface of the drop traces out the boundary layer. As a result, the eventual shape of the drop is a "pancake" of uniform thickness except at the rim, where surface tension effects are significant. The thickness of the pancake is simply the height where the drop surface first collides with the boundary layer.Comment: 5 pages, 3 figures, submitted to Physical Review Letter

Stable Carbon Isotope Signature of Methane Released From Phytoplankton

Unidad de excelencia María de Maeztu CEX2019-000940-MAquatic ecosystems play an important role in global methane cycling and many field studies have reported methane supersaturation in the oxic surface mixed layer (SML) of the ocean and in the epilimnion of lakes. The origin of methane formed under oxic condition is hotly debated and several pathways have recently been offered to explain the "methane paradox." In this context, stable isotope measurements have been applied to constrain methane sources in supersaturated oxygenated waters. Here we present stable carbon isotope signatures for six widespread marine phytoplankton species, three haptophyte algae and three cyanobacteria, incubated under laboratory conditions. The observed isotopic patterns implicate that methane formed by phytoplankton might be clearly distinguished from methane produced by methanogenic archaea. Comparing results from phytoplankton experiments with isotopic data from field measurements, suggests that algal and cyanobacterial populations may contribute substantially to methane formationobserved in the SML of oceans and lakes