Optimal perceived timing: integrating sensory information with dynamically updated expectations

The environment has a temporal structure, and knowing when a stimulus will appear translates into increased perceptual performance. Here we investigated how the human brain exploits temporal regularity in stimulus sequences for perception. We find that the timing of stimuli that occasionally deviate from a regularly paced sequence is perceptually distorted. Stimuli presented earlier than expected are perceptually delayed, whereas stimuli presented on time and later than expected are perceptually accelerated. This result suggests that the brain regularizes slightly deviant stimuli with an asymmetry that leads to the perceptual acceleration of expected stimuli. We present a Bayesian model for the combination of dynamically-updated expectations, in the form of a priori probability of encountering future stimuli, with incoming sensory information. The asymmetries in the results are accounted for by the asymmetries in the distributions involved in the computational process

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Temporal regularity of the environment drives time perception

It’s reasonable to assume that a regularly paced sequence should be perceived as regular, but here we show that perceived regularity depends on the context in which the sequence is embedded. We presented one group of participants with perceptually regularly paced sequences, and another group of participants with mostly irregularly paced sequences (75% irregular, 25% regular). The timing of the final stimulus in each sequence could be varied. In one experiment, we asked whether the last stimulus was regular or not. We found that participants exposed to an irregular environment frequently reported perfectly regularly paced stimuli to be irregular. In a second experiment, we asked participants to judge whether the final stimulus was presented before or after a flash. In this way, we were able to determine distortions in temporal perception as changes in the timing necessary for the sound and the flash to be perceived synchronous. We found that within a regular context, the perceived timing of deviant last stimuli changed so that the relative anisochrony appeared to be perceptually decreased. In the irregular context, the perceived timing of irregular stimuli following a regular sequence was not affected. These observations suggest that humans use temporal expectations to evaluate the regularity of sequences and that expectations are combined with sensory stimuli to adapt perceived timing to follow the statistics of the environment. Expectations can be seen as a-priori probabilities on which perceived timing of stimuli depend

First island-wide, single-day soil collection study on Crete reveals environmental drivers of microbial diversity

Understanding how environmental and ecological factors shape variability in soil-associated microbial communities is a complex problem, particularly on islands, which contain a wide range of diverse and unique geology, fauna, and flora. The island of Crete features sharp altitudinal gradients, diverse landscapes, and distinct ecological zones shaped by its complex geological history making it an ideal natural laboratory for studying how environmental variation influences soil microbial communities. In this study, we characterized the soil microbial communities across Crete's ecozones and identify environmental factors associated with their diversity and composition. We performed a single-day, island-wide soil microbiota investigation, the first of its kind, to address this challenge by eliminating sources of variability including seasonality, weather conditions, anthropogenic or land use changes over time, and ecological succession of microbial communities. This island collection event (Island Sampling Day, ISD) was conducted in conjunction with the annual meeting of the Genomic Standards Consortium, on the island of Crete, and utilized standard data and metadata collection protocols. We generated amplicon sequences (V3-V4 regions of the 16 S ribosomal RNA gene) and a metadata-enriched dataset from 435 soil samples across 72 sites and four distinct ecozones for future whole-island microbiome studies. Here we report on the study design and sample collection process along with our initial examination of the ecological drivers of soil microbial community variability (e.g., elevation, soil types, soil pH, soil moisture, vegetation type, land use) across the Crete ecozones (defined by elevation and distinct habitats)

Major submissions tool developments at the European nucleotide archive

The European Nucleotide Archive (ENA; http://www.ebi.ac.uk/ena), Europe's primary nucleotide sequence resource, captures and presents globally comprehensive nucleic acid sequence and associated information. Covering the spectrum from raw data to assembled and functionally annotated genomes, the ENA has witnessed a dramatic growth resulting from advances in sequencing technology and ever broadening application of the methodology. During 2011, we have continued to operate and extend the broad range of ENA services. In particular, we have released major new functionality in our interactive web submission system, Webin, through developments in template-based submissions for annotated sequences and support for raw next-generation sequence read submissions

Agroforesterie et services écosystémiques en zone tropicale

Respectueux de l’environnement et garantissant une sécurité alimentaire soutenue par la diversification des productions et des revenus qu’ils procurent, les systèmes agroforestiers apparaissent comme un modèle prometteur d’agriculture durable dans les pays du Sud les plus vulnérables aux changements globaux. Cependant, ces systèmes agroforestiers ne peuvent être optimisés qu’à condition de mieux comprendre et de mieux maîtriser les facteurs de leurs productions. L’ouvrage présente un ensemble de connaissances récentes sur les mécanismes biophysiques et socio-économiques qui sous-tendent le fonctionnement et la dynamique des systèmes agroforestiers. Il concerne, d’une part les systèmes agroforestiers à base de cultures pérennes, telles que cacaoyers et caféiers, de régions tropicales humides en Amérique du Sud, en Afrique de l’Est et du Centre, d’autre part les parcs arborés et arbustifs à base de cultures vivrières, principalement de céréales, de la région semi-aride subsaharienne d’Afrique de l’Ouest. Il synthétise les dernières avancées acquises grâce à plusieurs projets associant le Cirad, l’IRD et leurs partenaires du Sud qui ont été conduits entre 2012 et 2016 dans ces régions. L’ensemble de ces projets s’articulent autour des dynamiques des systèmes agroforestiers et des compromis entre les services de production et les autres services socio-écosystémiques que ces systèmes fournissent

BIOPOLE: biogeochemical processes and ecosystem functioning in changing polar systems and their global impacts

The export of elements (particularly carbon, nitrogen and phosphorus) from the Poles critically supports global marine biodiversity and major fisheries as well as the sequestration of atmospheric carbon to the deep ocean. Ecosystem processes regulate this export, but major uncertainties remain in terms of how and by how much. Progress on understanding key ecosystem interactions is hindered by lack of data and their representation in Earth system models is poor. The two polar regions share similarities in environmental extremes which make them sensitive to the impacts of climate change. They both receive nutrients from multiple and diverse sources and the delivery of these nutrients to other oceans is regulated by similar ecosystem processes. However, the extent to which these ecosystem processes will be modified by climate change is unclear and urgently needs to be determined. BIOPOLE will determine how polar ecosystems regulate the balance of carbon and nutrients in the world’s oceans and, through it, their effect on global fish stocks and carbon storage. It will address this challenge by integrating ambitious fieldwork campaigns and innovative modelling in a multidisciplinary and highly coordinated approach. BIOPOLE will capitalise on world-leading capabilities and infrastructure in ocean and high-latitude research, including cutting-edge land-based facilities, state-of-the-art polar research vessels and innovative autonomous instrumentation. Collaboration with national and international partners will further strengthen BIOPOLE’s multidisciplinary approach and efficient use of infrastructure. BIOPOLE’s legacy will be the first assessment of the global impact of polar ecosystems on biogeochemical cycling and fish stocks; technologically-novel approaches and strong partnerships between leading international science groups