A prominent account of prefrontal cortex (PFC) function is that single neurons within the PFC maintain representations of task-relevant stimuli in working memory. Evidence for this view comes from ...studies in which subjects hold a stimulus across a delay lasting up to several seconds. Persistent elevated activity in the PFC has been observed in animal models as well as in humans performing these tasks. This persistent activity has been interpreted as evidence for the encoding of the stimulus itself in working memory. However, recent findings have posed a challenge to this notion. A number of recent studies have examined neural data from the PFC and posterior sensory areas, both at the single neuron level in primates, and at a larger scale in humans, and have failed to find encoding of stimulus information in the PFC during tasks with a substantial working memory component. Strong stimulus related information, however, was seen in posterior sensory areas. These results suggest that delay period activity in the PFC might be better understood not as a signature of memory storage per se, but as a top down signal that influences posterior sensory areas where the actual working memory representations are maintained.
Electrophysiological signals exhibit both periodic and aperiodic properties. Periodic oscillations have been linked to numerous physiological, cognitive, behavioral and disease states. Emerging ...evidence demonstrates that the aperiodic component has putative physiological interpretations and that it dynamically changes with age, task demands and cognitive states. Electrophysiological neural activity is typically analyzed using canonically defined frequency bands, without consideration of the aperiodic (1/f-like) component. We show that standard analytic approaches can conflate periodic parameters (center frequency, power, bandwidth) with aperiodic ones (offset, exponent), compromising physiological interpretations. To overcome these limitations, we introduce an algorithm to parameterize neural power spectra as a combination of an aperiodic component and putative periodic oscillatory peaks. This algorithm requires no a priori specification of frequency bands. We validate this algorithm on simulated data, and demonstrate how it can be used in applications ranging from analyzing age-related changes in working memory to large-scale data exploration and analysis.
Neural populations can change the computation they perform on very short timescales. Although such flexibility is common, the underlying computational strategies at the population level remain ...unknown. To address this gap, we examined population responses in motor cortex during reach preparation and movement. We found that there exist exclusive and orthogonal population-level subspaces dedicated to preparatory and movement computations. This orthogonality yielded a reorganization in response correlations: the set of neurons with shared response properties changed completely between preparation and movement. Thus, the same neural population acts, at different times, as two separate circuits with very different properties. This finding is not predicted by existing motor cortical models, which predict overlapping preparation-related and movement-related subspaces. Despite orthogonality, responses in the preparatory subspace were lawfully related to subsequent responses in the movement subspace. These results reveal a population-level strategy for performing separate but linked computations.
•Impacts of future climate change scenarios on net aquifer recharge from rainfall.•Application in continental Spain, a varied territory sensitive to climate change.•Generation of potential climate ...scenarios by different ensembles of prediction.•Multi-criteria analysis of statistical downscaling techniques.•Simulation of climate scenarios within a distributed rainfall-recharge model.
Climate change will modify the availability of groundwater resources in the future. Thus the evaluation of average aquifer recharge from precipitation, and its uncertainty, becomes a key subject in determining suitable countrywide water policies. The confident prediction of renewable groundwater resources requires an accurate evaluation of aquifer recharge over time and space, especially in large territories with varied conditions for aquifer recharge such as continental Spain. This study asses impacts of future potential climatic change scenarios on distributed net aquifer recharge (NAR) from precipitation over continental Spain. For this, the used method (1) generates future time series of climatic variables (precipitation, temperature) spatially distributed over the territory for potential aquifer recharge (PAR), and (2) simulates them within previously calibrated spatial PAR or NAR recharge models from the available historical information to provide distributed PAR or NAR time series. The information employed comes from the Spain02 project for the historical climatic data, from Alcalá and Custodio (2014, 2015) for the historical spatial NAR, and from the CORDEX EU project (2013) regional climate models (RCMs) simulations for the future climate scenarios. A distributed empirical precipitation-recharge model is defined by using a regular 10km×10km grid, and assuming that precipitation (P) and temperature (T) are the most important climatic variables determining PAR, while their spatiotemporal variabilities determine the impacts of future potential climatic scenarios on renewable groundwater resources. Potential plausible pictures of future climate scenarios are defined by combining information coming from different RCMs and General Circulation models (GCMs), downscaling techniques, and ensemble hypothesis. These scenarios were simulated within the used precipitation-recharge model to estimate impacts on NAR. The results show that global mean NAR decreases by 12% on average over continental Spain. Over 99.8% of the territory, a variable degree of recharge reduction is obtained; the reduction is quite heterogeneously distributed in line with the variety of conditions for aquifer recharge over continental Spain. The standard deviation of annual mean NAR will increase by 8% on average in the future. The dependence of these changes regarding potential explanatory variables, such as elevation and latitude was also analysed.
A dominant view of prefrontal cortex (PFC) function is that it stores task-relevant information in working memory. To examine this and determine how it applies when multiple pieces of information ...must be stored, we trained two subjects to perform a multi-item color change detection task and recorded activity of neurons in PFC. Few neurons encoded the color of the items. Instead, the predominant encoding was spatial: a static signal reflecting the item's position and a dynamic signal reflecting the subject's covert attention. These findings challenge the notion that PFC stores task-relevant information. Instead, we suggest that the contribution of PFC is in controlling the allocation of resources to support working memory. In support of this, we found that increased power in the alpha and theta bands of PFC local field potentials, which are thought to reflect long-range communication with other brain areas, was correlated with more precise color representations.
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Areas where there is a scarcity of water frequently experience significant drought periods, which may become exacerbated in the future due to climate change. In this paper we propose a novel and ...integrated method for a semi-distributed analysis of the impact on potential future meteorological, hydrological, agronomical and operational droughts within a basin. We analyse the propagation and correlation of the different types of droughts, and then this analysis can be used to plan sustainable adaptation strategies. The proposed method is based on sequential applications of different statistical techniques and mathematical models. We have applied several statistical downscaling techniques to generate consistent local future climate scenarios considering both basic and drought statistics. This allows us to analyse the sensitivity of the results to the applied technique and the spatial distribution. A chain of models has been used to propagate climate scenarios to analyse the hydrological, agricultural, and operational impact. We have applied a clustering analysis to historical data to identify homogeneous hydro-climate areas used to analyse the spatial distribution of the impact. The approach has been applied in the Segura basin (in south-eastern Spain). The simulations of the impact in the 3 generated ensemble scenarios on the whole Segura Basin system for the horizon 2071–2100 under the RCP8.5 emission scenario show a significant mean reduction (40.9–59.1%) of the available resources, an increase in pumping rates in aquifers (36.4–42.7%) and lower guarantees (96.3% in the historical period and 75.0–77.6% in the future scenarios) for demand supply. The spatial distribution of the impact is heterogeneous, with the hydro-climate areas near to the coast for agricultural and operational droughts being more affected. An analysis of correlation between the meteorological and operational droughts shows the maximum correlation for a time delay of around 4 months. This information could help to identify when measures to reduce the operational impact should start to be applied when a meteorological drought starts.
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•Novel method to analyse climate change impacts on future droughts at basin scale•Results in Segura Basin show significant worsening of future droughts features.•Impacts on agricultural and operational droughts are higher for lower-coastal areas.•Maximum correlation meteorological-operational droughts for time delay of 4 months•Correlation delay can help to anticipate measures to reduce operational impacts.
The mean precipitation measurements in a Mediterranean Alpine catchment in Sierra Nevada show an inversion of the gradient with the altitude beyond a certain threshold. Is it due to a real pattern or ...it can be explained by systematic error of solid precipitation measurement in gauges? Can we assess climatic fields in an alpine catchment from gauge measurement? This article describes a research developed to answer both questions in the Alto Genil Basin. As commonly happens in most of the basins, the spatio‐temporal information from climate gauges is limited; therefore to reduce uncertainty in estimates of climatic fields, some secondary information should be introduced. Since orographic conditions clearly influence precipitation, the relationship between this climatic variable and elevation is usually included as secondary information into the estimates. However, while there is a clear relationship between temperature and elevation, the relationship between precipitation and elevation is not so simple. In this article the analysis of the data performed allow us to demonstrate that there is a real inversion of the gradient within this Mediterranean Alpine area as other authors previously pointed in some tropical and subtropical zones. The intensity of this phenomenon and the altitude threshold from which it appears can be altered as a consequence of the undercath of the solid precipitation. To estimate precipitation fields, we have used different hypotheses about the intensity of the undercatch taking into account empirical corrections obtained for nearby mountain ranges. An analysis of the sensitivity of the results to the assumed undercatch hypothesis shows that it is not possible to estimate properly precipitation fields (the sensitivity of the results to the adopted hypothesis is high) in these alpine areas if we only have information about the precipitation measurements at the stations.
Relationship between precipitation and elevation is usually included as secondary information into the estimates. In this article the analysis of the data allow us to demonstrate that there is a real inversion of the precipitation gradient within this Mediterranean Alpine area as other authors previously pointed in some tropical zones. The analyses of the climatic data during the non‐snow period allowed us to conclude that there is a real inversion pattern, but that the snow undercatch phenomenon may intensify it.
High-throughput automated sequencing has enabled an exponential growth rate of sequencing data. This requires increasing sequence quality and reliability in order to avoid database contamination with ...artefactual sequences. The arrival of pyrosequencing enhances this problem and necessitates customisable pre-processing algorithms.
SeqTrim has been implemented both as a Web and as a standalone command line application. Already-published and newly-designed algorithms have been included to identify sequence inserts, to remove low quality, vector, adaptor, low complexity and contaminant sequences, and to detect chimeric reads. The availability of several input and output formats allows its inclusion in sequence processing workflows. Due to its specific algorithms, SeqTrim outperforms other pre-processors implemented as Web services or standalone applications. It performs equally well with sequences from EST libraries, SSH libraries, genomic DNA libraries and pyrosequencing reads and does not lead to over-trimming.
SeqTrim is an efficient pipeline designed for pre-processing of any type of sequence read, including next-generation sequencing. It is easily configurable and provides a friendly interface that allows users to know what happened with sequences at every pre-processing stage, and to verify pre-processing of an individual sequence if desired. The recommended pipeline reveals more information about each sequence than previously described pre-processors and can discard more sequencing or experimental artefacts.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Rab GTPases in Parkinson's disease: a primer Lara Ordóñez, Antonio Jesús; Fasiczka, Rachel; Naaldijk, Yahaira ...
Essays in biochemistry,
12/2021, Letnik:
65, Številka:
7
Journal Article
Recenzirano
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Parkinson's disease is a prominent and debilitating movement disorder characterized by the death of vulnerable neurons which share a set of structural and physiological properties. Over the recent ...years, increasing evidence indicates that Rab GTPases can directly as well as indirectly contribute to the cellular alterations leading to PD. Rab GTPases are master regulators of intracellular membrane trafficking events, and alterations in certain membrane trafficking steps can be particularly disruptive to vulnerable neurons. Here, we describe current knowledge on the direct links between altered Rab protein function and PD pathomechanisms.
A central question in behavioral science is how we select among choice alternatives to obtain consistently the most beneficial outcomes. Three variables are particularly important when making a ...decision: the potential payoff, the probability of success, and the cost in terms of time and effort. A key brain region in decision making is the frontal cortex as damage here impairs the ability to make optimal choices across a range of decision types. We simultaneously recorded the activity of multiple single neurons in the frontal cortex while subjects made choices involving the three aforementioned decision variables. This enabled us to contrast the relative contribution of the anterior cingulate cortex (ACC), the orbito-frontal cortex, and the lateral prefrontal cortex to the decision-making process. Neurons in all three areas encoded value relating to choices involving probability, payoff, or cost manipulations. However, the most significant signals were in the ACC, where neurons encoded multiplexed representations of the three different decision variables. This supports the notion that the ACC is an important component of the neural circuitry underlying optimal decision making.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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