18 research outputs found

    Health news sharing is reflected in distributed reward-related brain activity

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    Neuroimaging has identified individual brain regions, but not yet whole-brain patterns, that correlate with the population impact of health messaging. We used neuroimaging to measure whole-brain responses to health news articles across two studies. Beyond activity in core reward value-related regions (ventral striatum, ventromedial prefrontal cortex), our approach leveraged whole-brain responses to each article, quantifying expression of a distributed pattern meta-analytically associated with reward valuation. The results indicated that expression of this whole-brain pattern was associated with population-level sharing of these articles beyond previously identified brain regions and self-report variables. Further, the efficacy of the meta-analytic pattern was not reducible to patterns within core reward value-related regions but rather depended on larger-scale patterns. Overall, this work shows that a reward-related pattern of whole-brain activity is related to health information sharing, advancing neuroscience models of the mechanisms underlying the spread of health information through a population

    SPIDER: Probing the Early Universe with a Suborbital Polarimeter

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    We evaluate the ability of SPIDER, a balloon-borne polarimeter, to detect a divergence-free polarization pattern ("B-modes") in the Cosmic Microwave Background (CMB). In the inflationary scenario, the amplitude of this signal is proportional to that of the primordial scalar perturbations through the tensor-to-scalar ratio r. We show that the expected level of systematic error in the SPIDER instrument is significantly below the amplitude of an interesting cosmological signal with r=0.03. We present a scanning strategy that enables us to minimize uncertainty in the reconstruction of the Stokes parameters used to characterize the CMB, while accessing a relatively wide range of angular scales. Evaluating the amplitude of the polarized Galactic emission in the SPIDER field, we conclude that the polarized emission from interstellar dust is as bright or brighter than the cosmological signal at all SPIDER frequencies (90 GHz, 150 GHz, and 280 GHz), a situation similar to that found in the "Southern Hole." We show that two ~20-day flights of the SPIDER instrument can constrain the amplitude of the B-mode signal to r<0.03 (99% CL) even when foreground contamination is taken into account. In the absence of foregrounds, the same limit can be reached after one 20-day flight.Comment: 29 pages, 8 figures, 4 tables; v2: matches published version, flight schedule updated, two typos fixed in Table 2, references and minor clarifications added, results unchange

    Planck 2018 results. IV. Diffuse component separation

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    We present full-sky maps of the cosmic microwave background (CMB) and polarized synchrotron and thermal dust emission, derived from the third set of Planck frequency maps. These products have significantly lower contamination from instrumental systematic effects than previous versions. The methodologies used to derive these maps follow closely those described in earlier papers, adopting four methods (Commander, NILC, SEVEM, and SMICA) to extract the CMB component, as well as three methods (Commander, GNILC, and SMICA) to extract astrophysical components. Our revised CMB temperature maps agree with corresponding products in the Planck 2015 delivery, whereas the polarization maps exhibit significantly lower large-scale power, reflecting the improved data processing described in companion papers; however, the noise properties of the resulting data products are complicated, and the best available end-to-end simulations exhibit relative biases with respect to the data at the few percent level. Using these maps, we are for the first time able to fit the spectral index of thermal dust independently over 3 degree regions. We derive a conservative estimate of the mean spectral index of polarized thermal dust emission of beta_d = 1.55 +/- 0.05, where the uncertainty marginalizes both over all known systematic uncertainties and different estimation techniques. For polarized synchrotron emission, we find a mean spectral index of beta_s = -3.1 +/- 0.1, consistent with previously reported measurements. We note that the current data processing does not allow for construction of unbiased single-bolometer maps, and this limits our ability to extract CO emission and correlated components. The foreground results for intensity derived in this paper therefore do not supersede corresponding Planck 2015 products. For polarization the new results supersede the corresponding 2015 products in all respects

    Planck 2018 results. III. High Frequency Instrument data processing and frequency maps

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    This paper presents the High Frequency Instrument (HFI) data processing procedures for the Planck 2018 release. Major improvements in mapmaking have been achieved since the previous 2015 release. They enabled the first significant measurement of the reionization optical depth parameter using HFI data. This paper presents an extensive analysis of systematic effects, including the use of simulations to facilitate their removal and characterize the residuals. The polarized data, which presented a number of known problems in the 2015 Planck release, are very significantly improved. Calibration, based on the CMB dipole, is now extremely accurate and in the frequency range 100 to 353 GHz reduces intensity-to-polarization leakage caused by calibration mismatch. The Solar dipole direction has been determined in the three lowest HFI frequency channels to within one arc minute, and its amplitude has an absolute uncertainty smaller than 0.35ÎŒ0.35\muK, an accuracy of order 10−410^{-4}. This is a major legacy from the HFI for future CMB experiments. The removal of bandpass leakage has been improved by extracting the bandpass-mismatch coefficients for each detector as part of the mapmaking process; these values in turn improve the intensity maps. This is a major change in the philosophy of "frequency maps", which are now computed from single detector data, all adjusted to the same average bandpass response for the main foregrounds. Simulations reproduce very well the relative gain calibration of detectors, as well as drifts within a frequency induced by the residuals of the main systematic effect. Using these simulations, we measure and correct the small frequency calibration bias induced by this systematic effect at the 10−410^{-4} level. There is no detectable sign of a residual calibration bias between the first and second acoustic peaks in the CMB channels, at the 10−310^{-3} level

    Planck 2018 results. XII. Galactic astrophysics using polarized dust emission

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    We present 353 GHz full-sky maps of the polarization fraction pp, angle ψ\psi, and dispersion of angles SS of Galactic dust thermal emission produced from the 2018 release of Planck data. We confirm that the mean and maximum of pp decrease with increasing NHN_H. The uncertainty on the maximum polarization fraction, pmax=22.0p_\mathrm{max}=22.0% at 80 arcmin resolution, is dominated by the uncertainty on the zero level in total intensity. The observed inverse behaviour between pp and SS is interpreted with models of the polarized sky that include effects from only the topology of the turbulent Galactic magnetic field. Thus, the statistical properties of pp, ψ\psi, and SS mostly reflect the structure of the magnetic field. Nevertheless, we search for potential signatures of varying grain alignment and dust properties. First, we analyse the product map S×pS \times p, looking for residual trends. While pp decreases by a factor of 3--4 between NH=1020N_H=10^{20} cm−2^{-2} and NH=2×1022N_H=2\times 10^{22} cm−2^{-2}, S×pS \times p decreases by only about 25%, a systematic trend observed in both the diffuse ISM and molecular clouds. Second, we find no systematic trend of S×pS \times p with the dust temperature, even though in the diffuse ISM lines of sight with high pp and low SS tend to have colder dust. We also compare Planck data with starlight polarization in the visible at high latitudes. The agreement in polarization angles is remarkable. Two polarization emission-to-extinction ratios that characterize dust optical properties depend only weakly on NHN_H and converge towards the values previously determined for translucent lines of sight. We determine an upper limit for the polarization fraction in extinction of 13%, compatible with the pmaxp_\mathrm{max} observed in emission. These results provide strong constraints for models of Galactic dust in diffuse gas

    Neural Valuation of Antidrinking Campaigns and Risky Peer Influence in Daily Life

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    Objective : Health behavior is affected by competing sources of influence like media messages and peers. In the context of alcohol consumption, college students are targeted by antidrinking media messages, but tend to have proalcohol conversations with peers. How do humans integrate competing sources of influence on daily behavior? We observed individuals under exposure to antialcohol media messages and proalcohol conversations and tested a "common neural value" account of how contradictory influences are integrated to affect behavior.  Methods : Participants were instructed to cognitively regulate responses to antidrinking media messages while undergoing fMRI at baseline. Individual differences in success in message-consistent or -derogating regulation were indexed by changes in activity within the neural valuation system (ventral striatum/VS, ventromedial prefrontal cortex/VMPFC), providing a proxy for success in finding value in message-consistent/-derogating engagement. To measure peer influence, we tracked daily drinking-related conversations and drinking behavior for 30 days using mobile electronic diaries.  Results : Peer conversations, on average, were positive toward drinking. More positive conversations led to more future drinking, particularly for participants who showed greater neural value signals when derogating antidrinking media. Susceptibility to risky peer influence decreased with increasing success in up-regulating message-consistent neural valuation responses to antidrinking media. Neural effects were driven by VS-activity.  Conclusions : Results are consistent with a dynamic value integration process where contradictory influences inform a common neural value signal. Reductions in the value of a behavior (through antidrinking campaigns) may buffer against future value increases after exposure to competing influences (proalcohol peers) with important real-world consequences

    Cognitive regulation of ventromedial prefrontal activity evokes lasting change in the perceived self-relevance of persuasive messaging

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    Persuasive messages can change people's thoughts, feelings, and actions, but these effects depend on how people think about and appraise the meaning of these messages. Drawing from research on the cognitive control of emotion, we used neuroimaging to investigate neural mechanisms underlying cognitive regulation of the affective and persuasive impact of advertisements communicating the risks of binge drinking, a significant public health problem. Using cognitive control to up-regulate (vs. down-regulate) responses to the ads increased: negative affect related to consequences of excessive drinking, perceived ad effectiveness, and ratings of ad self-relevance made after a one-hour delay. Neurally, these effects of cognitive control were mediated by goal-congruent modulation of ventromedial prefrontal cortex and distributed brain patterns associated with negative emotion and subjective valuation. These findings suggest that people can leverage cognitive control resources to deliberately shape responses to persuasive appeals, and identify mechanisms of emotional reactivity and integrative valuation that underlie this ability. Specifically, brain valuation pattern expression mediated the effect of cognitive goals on perceived message self-relevance, suggesting a role for the brain's valuation system in shaping responses to persuasive appeals in a manner that persists over time

    Brain activity tracks population information sharing by capturing consensus judgments of value

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    Information that is shared widely can profoundly shape society. Evidence from neuroimaging suggests that activity in the ventromedial prefrontal cortex (vmPFC), a core region of the brain’s valuation system tracks with this sharing. However, the mechanisms linking vmPFC responses in individuals to population behavior are still unclear. We used a multilevel brain-as-predictor approach to address this gap, finding that individual differences in how closely vmPFC activity corresponded with population news article sharing related to how closely its activity tracked with social consensus about article value. Moreover, how closely vmPFC activity corresponded with population behavior was linked to daily life news experience: frequent news readers tended to show high vmPFC across all articles, whereas infrequent readers showed high vmPFC only to articles that were more broadly valued and heavily shared. Using functional connectivity analyses, we found that superior tracking of consensus value was related to decreased connectivity of vmPFC with a dorsolateral PFC region associated with controlled processing. Taken together, our results demonstrate variability in the brain’s capacity to track crowd wisdom about information value, and suggest (lower levels of) stimulus experience and vmPFC–dlPFC connectivity as psychological and neural sources of this variability
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