A major challenge for systems neuroscience is to break the neural code. Computational algorithms for encoding information into neural activity and extracting information from measured activity afford ...understanding of how percepts, memories, thought, and knowledge are represented in patterns of brain activity. The past decade and a half has seen significant advances in the development of methods for decoding human neural activity, such as multivariate pattern classification, representational similarity analysis, hyperalignment, and stimulus-model-based encoding and decoding. This article reviews these advances and integrates neural decoding methods into a common framework organized around the concept of high-dimensional representational spaces.
We present a high-dimensional model of the representational space in human ventral temporal (VT) cortex in which dimensions are response-tuning functions that are common across individuals and ...patterns of response are modeled as weighted sums of basis patterns associated with these response tunings. We map response-pattern vectors, measured with fMRI, from individual subjects' voxel spaces into this common model space using a new method, “hyperalignment.” Hyperalignment parameters based on responses during one experiment—movie viewing—identified 35 common response-tuning functions that captured fine-grained distinctions among a wide range of stimuli in the movie and in two category perception experiments. Between-subject classification (BSC, multivariate pattern classification based on other subjects' data) of response-pattern vectors in common model space greatly exceeded BSC of anatomically aligned responses and matched within-subject classification. Results indicate that population codes for complex visual stimuli in VT cortex are based on response-tuning functions that are common across individuals.
► Response-tuning functions for visual population codes are common across individuals ► 35 response basis functions capture fine-grained distinctions among representations ► The common model space greatly improves between-subject classification of fMRI data ► The model has general validity across brains and across a wide range of stimuli
Patients with cancer are increasingly at risk for venous thromboembolism (VTE). Rates of VTE, however, vary markedly among patients with cancer.
This review focuses on recent data derived from ...population-based, hospital-based, and outpatient cohort studies of patients with cancer that have identified multiple clinical risk factors as well as candidate laboratory biomarkers predictive of VTE.
Clinical risk factors for cancer-associated VTE include primary tumor site, stage, initial period after diagnosis, presence and number of comorbidities, and treatment modalities including systemic chemotherapy, antiangiogenic therapy, and hospitalization. Candidate predictive biomarkers include elevated platelet or leukocyte counts, tissue factor, soluble P-selectin, and D-dimer. A recently validated risk model, incorporating some of these factors, can help differentiate patients at high or low risk for developing VTE while receiving chemotherapy.
Identifying patients with cancer who are most at risk for VTE is essential to better target thromboprophylaxis, with the eventual goal of reducing the burden as well as the consequences of VTE for patients with cancer.
Abstract Rubble pile asteroids are widely understood to be composed of reaccumulated debris following a catastrophic collision between asteroids in the main asteroid belt, where each disruption can ...make a family of new asteroids. Near-Earth asteroids Ryugu and Bennu have been linked to collisional families in the main asteroid belt, but surface age analyses of each asteroid suggest these bodies are substantially younger than their putative families. Here we show, through a coupled collisional and dynamical evolution of members of these families, that neither asteroid was likely to have been created at the same time as the original family breakups, but rather are likely remnants of later disruptions of original family members, making them second, or later, generation remnants. Our model finds about 80% and 60% of asteroids currently being delivered to near-Earth orbits from the respective families of New Polana and Eulalia are second or later generation. These asteroids delivered today in the 0.5-1 km size range have median ages since their last disruption that are substantially younger than the family age, reconciling their measured crater retention ages with membership in these families.
Asteroid shapes and hydration levels can serve as tracers of their history and origin. For instance, the asteroids (162173) Ryugu and (101955) Bennu have an oblate spheroidal shape with a pronounced ...equator, but contain different surface hydration levels. Here we show, through numerical simulations of large asteroid disruptions, that oblate spheroids, some of which have a pronounced equator defining a spinning top shape, can form directly through gravitational reaccumulation. We further show that rubble piles formed in a single disruption can have similar porosities but variable degrees of hydration. The direct formation of top shapes from single disruption alone can explain the relatively old crater-retention ages of the equatorial features of Ryugu and Bennu. Two separate parent-body disruptions are not necessarily required to explain their different hydration levels.
To generate a taxonomy of potentially morally injurious events (PMIE) encountered in veterinary care and develop an instrument to measure moral distress and posttraumatic growth following exposure to ...PMIE in the veterinary population.
Development and preliminary evaluation of the Moral Distress-Posttraumatic Growth Scale for Veterinary Professionals (MD-PTG-VP) employed data from veterinary professionals (veterinarians, veterinary nurses, veterinary technicians) from Australia and New Zealand across three phases: (1) item generation, (2) content validation, and (3) construct validation. In Phase 1 respondents (n = 46) were asked whether they had experienced any of six PMIE and to identify any PMIE not listed that they had experienced. In Phase 2 a different group of respondents (n = 11) assessed a list of 10 PMIE for relevance, clarity and appropriateness. In Phase 3 the final instrument was tested with a third group of respondents (n = 104) who also completed the Short Post-Traumatic Stress Disorder Rating Interview (SPRINT), a measure of posttraumatic stress, and the Stress-Related Growth Scale-Short Form (SRGS-SF) a measure of perceived posttraumatic growth. Spearman's correlation coefficients were calculated between respondent scores on each of the MD-PTG-VP subscales, the SPRINT, and the SRGS-SF to assess construct validity.
A 10-item taxonomy of PMIE encountered in veterinary care was generated in Phase 1. Items were deemed relevant, clear and appropriate by veterinary professionals in Phase 2. These were included in the developed instrument which measures frequency and impact of exposure to 10 PMIE, yielding three subscale scores (exposure frequency, moral distress, and posttraumatic growth). Assessment of construct validity by measuring correlation with SPRINT and SRGS-SF indicated satisfactory validity.
The MD-PTG-VP provides an informative tool that can be employed to examine professionals' mental health and wellbeing following exposure to PMIE frequently encountered in animal care. Further evaluation is required to ascertain population norms and confirm score cut-offs that reflect clinical presentation.
Once fully validated this instrument may be useful to quantify the frequency and intensity of positive and negative aspects of PMIE exposure on veterinary professionals so that accurate population comparisons can be made and changes measured over time.
PDF
