SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Code

171

Cracking brain’s neural code is of general interest. In contrast to the traditional view that enormous spike variability in resting states and stimulus-triggered responses reflects noise, here, we examine the “Neural Self-Information Theory” that the interspike-interval (ISI), or the silence-duration between 2 adjoining spikes, carries self-information that is inversely proportional to its variability-probability. Specifically, higher-probability ISIs convey minimal information because they reflect the ground state, whereas lower-probability ISIs carry more information, in the form of “positive” or “negative surprisals,” signifying the excitatory or inhibitory shifts from the ground state, respectively. These surprisals serve as the quanta of information to construct temporally coordinated cell-assembly ternary codes representing real-time cognitions. Accordingly, we devised a general decoding method and unbiasedly uncovered 15 cell assemblies underlying different sleep cycles, fear-memory experiences, spatial navigation, and 5-choice serial-reaction time (5CSRT) visual-discrimination behaviors. We further revealed that robust cell-assembly codes were generated by ISI surprisals constituted of ~20% of the skewed ISI gamma-distribution tails, conforming to the “Pareto Principle” that specifies, for many events-including communication-roughly 80% of the output or consequences come from 20% of the input or causes. These results demonstrate that real-time neural coding arises from the temporal assembly of neural-clique members via silence variability-based self-information codes.

Concepts: Self-information, Neural coding, Quantum mechanics, DNA, Psychology, Code, Information theory, Neuroscience

170

A major challenge of current high-throughput sequencing experiments is not only the generation of the sequencing data itself but also their processing, storage and transmission. The enormous size of these data motivates the development of data compression algorithms usable for the implementation of the various storage policies that are applied to the produced intermediate and final result files. In this article, we present NGC, a tool for the compression of mapped short read data stored in the wide-spread SAM format. NGC enables lossless and lossy compression and introduces the following two novel ideas: first, we present a way to reduce the number of required code words by exploiting common features of reads mapped to the same genomic positions; second, we present a highly configurable way for the quantization of per-base quality values, which takes their influence on downstream analyses into account. NGC, evaluated with several real-world data sets, saves 33-66% of disc space using lossless and up to 98% disc space using lossy compression. By applying two popular variant and genotype prediction tools to the decompressed data, we could show that the lossy compression modes preserve >99% of all called variants while outperforming comparable methods in some configurations.

Concepts: Huffman coding, Portable Network Graphics, Information theory, Code, Rate–distortion theory, JPEG, Lossless data compression, Data compression

29

The International Classification of Diseases-10 (ICD-10) is a new system that is a federally mandated change affecting all payers and providers, and is expected to exceed both the Health Insurance Portability and Accountability Act (HIPAA) and Y2K in terms of costs and risks. In 2003, HIPAA named ICD-9 as the code set for supporting diagnoses and procedures in electronic administrative transactions. However, on 16 January 2009, the Department of Health and Human Services published a regulation requiring the replacement of ICD-9 with ICD-10 as of 1 October 2013. While ICD-9 and ICD-10 have a similar type of hierarchy in their structures, ICD-10 is more complex and incorporates numerous changes. Overall, ICD-10 contains more than 141 000 codes, a whopping 712% increase over the <20 000 codes in ICD-9, creating enormous complexities, confusion and expense. Published statistics illustrate that there are instances where a single ICD-9 code can map to more than 50 distinct ICD-10 codes. Also, there are multiple instances where a single ICD-10 code can map to more than one ICD-9 code. Proponents of the new ICD-10 system argue that the granularity should lead to improvements in the quality of healthcare whereas detractors of the system see the same granularity as burdensome. The estimated cost per physician is projected to range from $25 000 to $50 000.

Concepts: ICD-10, Code, National Provider Identifier, Health care, Source code, Health insurance, Medicare, Health Insurance Portability and Accountability Act

28

Component coding is the method NeuroInterventionalists have used for the past 20 years to bill procedural care. The term refers to separate billing for each discrete aspect of a surgical or interventional procedure, and has typically allowed billing the procedural activity, such as catheterization of vessels, separately from the diagnostic evaluation of radiographic images. This work is captured by supervision and interpretation codes. Benefits of component coding will be reviewed in this article. The American Medical Association/Specialty Society Relative Value Scale Update Committee has been filtering for codes that are frequently reported together. NeuroInterventional procedures are going to be caught in this filter as our codes are often reported simultaneously as for example routinely occurs when procedural codes are coupled to those for supervision and interpretation. Unfortunately, history has shown that when bundled codes have been reviewed at the RUC, there has been a trend to lower overall RVU value for the combined service compared with the sum of the values of the separate services.

Concepts: Code, Integrity, Interventional neuroradiology, Filter, Value, Summation, Addition, Object-oriented programming

26

Maps are a mainstay of visual, somatosensory, and motor coding in many species. However, auditory maps of space have not been reported in the primate brain. Instead, recent studies have suggested that sound location may be encoded via broadly responsive neurons whose firing rates vary roughly proportionately with sound azimuth. Within frontal space, maps and such rate codes involve different response patterns at the level of individual neurons. Maps consist of neurons exhibiting circumscribed receptive fields, whereas rate codes involve open-ended response patterns that peak in the periphery. This coding format discrepancy therefore poses a potential problem for brain regions responsible for representing both visual and auditory information. Here, we investigated the coding of auditory space in the primate superior colliculus(SC), a structure known to contain visual and oculomotor maps for guiding saccades. We report that, for visual stimuli, neurons showed circumscribed receptive fields consistent with a map, but for auditory stimuli, they had open-ended response patterns consistent with a rate or level-of-activity code for location. The discrepant response patterns were not segregated into different neural populations but occurred in the same neurons. We show that a read-out algorithm in which the site and level of SC activity both contribute to the computation of stimulus location is successful at evaluating the discrepant visual and auditory codes, and can account for subtle but systematic differences in the accuracy of auditory compared to visual saccades. This suggests that a given population of neurons can use different codes to support appropriate multimodal behavior.

Concepts: Geography, Brain, Time, Sensory system, Code, Nervous system, Visual perception, Retina

25

Develop and test web services to retrieve and identify the most precise ICD-10-CM code(s) for a given clinical encounter. Facilitate creation of user interfaces that 1) provide an initial shortlist of candidate codes, ideally visible on a single screen; and 2) enable code refinement.

Concepts: Application programming interface, Source code, Systematized Nomenclature of Medicine, User interface, SNOMED CT, Code, Clinical Data Interchange Standards Consortium, Java

20

Community composition within the human microbiome varies across individuals, but it remains unknown if this variation is sufficient to uniquely identify individuals within large populations or stable enough to identify them over time. We investigated this by developing a hitting set-based coding algorithm and applying it to the Human Microbiome Project population. Our approach defined body site-specific metagenomic codes: sets of microbial taxa or genes prioritized to uniquely and stably identify individuals. Codes capturing strain variation in clade-specific marker genes were able to distinguish among 100s of individuals at an initial sampling time point. In comparisons with follow-up samples collected 30-300 d later, ∼30% of individuals could still be uniquely pinpointed using metagenomic codes from a typical body site; coincidental (false positive) matches were rare. Codes based on the gut microbiome were exceptionally stable and pinpointed >80% of individuals. The failure of a code to match its owner at a later time point was largely explained by the loss of specific microbial strains (at current limits of detection) and was only weakly associated with the length of the sampling interval. In addition to highlighting patterns of temporal variation in the ecology of the human microbiome, this work demonstrates the feasibility of microbiome-based identifiability-a result with important ethical implications for microbiome study design. The datasets and code used in this work are available for download from huttenhower.sph.harvard.edu/idability.

Concepts: Identification, Sampling, Genetics, Microbiology, Bacteria, Archaea, Code, DNA

12

Using Ca(2+) imaging in freely behaving mice that repeatedly explored a familiar environment, we tracked thousands of CA1 pyramidal cells' place fields over weeks. Place coding was dynamic, as each day the ensemble representation of this environment involved a unique subset of cells. However, cells in the ∼15-25% overlap between any two of these subsets retained the same place fields, which sufficed to preserve an accurate spatial representation across weeks.

Concepts: Code, Subset, Dynamics, Geography, Gene, DNA, Mathematics, Pyramidal cell

11

The frontal eye fields (FEFs) participate in both working memory and sensorimotor transformations for saccades, but their role in integrating these functions through time remains unclear. Here, we tracked FEF spatial codes through time using a novel analytic method applied to the classic memory-delay saccade task. Three-dimensional recordings of head-unrestrained gaze shifts were made in two monkeys trained to make gaze shifts toward briefly flashed targets after a variable delay (450-1500 ms). A preliminary analysis of visual and motor response fields in 74 FEF neurons eliminated most potential models for spatial coding at the neuron population level, as in our previous study (Sajad et al., 2015). We then focused on the spatiotemporal transition from an eye-centered target code (T; preferred in the visual response) to an eye-centered intended gaze position code (G; preferred in the movement response) during the memory delay interval. We treated neural population codes as a continuous spatiotemporal variable by dividing the space spanning T and G into intermediate T-G models and dividing the task into discrete steps through time. We found that FEF delay activity, especially in visuomovement cells, progressively transitions from T through intermediate T-G codes that approach, but do not reach, G. This was followed by a final discrete transition from these intermediate T-G delay codes to a “pure” G code in movement cells without delay activity. These results demonstrate that FEF activity undergoes a series of sensory-memory-motor transformations, including a dynamically evolving spatial memory signal and an imperfect memory-to-motor transformation.

Concepts: Nervous system, Coding theory, Code, Frontal eye fields, Eye

9

Pulmonary rehabilitation is recommended for patients with COPD to improve physical function, breathlessness and quality of life. Using The Health Information Network (THIN) primary care database in UK, we compared the demographic and clinical parameters of patients with COPD in relation to coding of pulmonary rehabilitation, and to investigate whether there is a survival benefit from pulmonary rehabilitation. We identified patients with COPD, diagnosed from 2004 and extracted information on demographics, pulmonary rehabilitation and clinical parameters using the relevant Read codes. Thirty six thousand one hundred and eighty nine patients diagnosed with COPD were included with a mean (SD) age of 67 (11) years, 53% were male and only 9.8% had a code related to either being assessed, referred, or completing pulmonary rehabilitation ever. Younger age at diagnosis, better socioeconomic status, worse dyspnoea score, current smoking, and higher comorbidities level are more likely to have a record of pulmonary rehabilitation. Of those with a recorded MRC of 3 or worse, only 2057 (21%) had a code of pulmonary rehabilitation. Survival analysis revealed that patients with coding for pulmonary rehabilitation were 22% (95% CI 0.69-0.88) less likely to die than those who had no coding. In UK THIN records, a substantial proportion of eligible patients with COPD have not had a coded pulmonary rehabilitation record. Survival was improved in those with PR record but coding for other COPD treatments were also better in this group. GP practices need to improve the coding for PR to highlight any unmet need locally.

Concepts: Pneumonia, Shortness of breath, Source code, Gramophone record, Chronic obstructive pulmonary disease, Improve, Better, Code