Brains, it has recently been argued, are essentially prediction machines. They are bundles of cells that support perception and action by constantly attempting to match incoming sensory inputs with top-down expectations or predictions. This is achieved using a hierarchical generative model that aims to minimize prediction error within a bidirectional cascade of cortical processing. Such accounts offer a unifying model of perception and action, illuminate the functional role of attention, and may neatly capture the special contribution of cortical processing to adaptive success. This target article critically examines this "hierarchical prediction machine" approach, concluding that it offers the best clue yet to the shape of a unified science of mind and action. Sections 1 and 2 lay out the key elements and implications of the approach. Section 3 explores a variety of pitfalls and challenges, spanning the evidential, the methodological, and the more properly conceptual. The paper ends (sections 4 and 5) by asking how such approaches might impact our more general vision of mind, experience, and agency.

/pdf/whatever-next-predictive-brains-situated-agents-and-the-epj56cs868.pdf

Whatever next? Predictive brains, situated agents, and the future of cognitive science

We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.

/pdf/science-and-technology-roadmap-for-graphene-related-two-4q9m7czlkc.pdf

Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems

Neuronal Synchrony: A Versatile Code for the Definition of Relations?

The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on 2012 June 13, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates in the band from 3 to 79 keV, extending the sensitivity of focusing far beyond the ~10 keV high-energy cutoff achieved by all previous X-ray satellites. The inherently low background associated with concentrating the X-ray light enables NuSTAR to probe the hard X-ray sky with a more than 100-fold improvement in sensitivity over the collimated or coded mask instruments that have operated in this bandpass. Using its unprecedented combination of sensitivity and spatial and spectral resolution, NuSTAR will pursue five primary scientific objectives: (1) probe obscured active galactic nucleus (AGN) activity out to the peak epoch of galaxy assembly in the universe (at z ≾ 2) by surveying selected regions of the sky; (2) study the population of hard X-ray-emitting compact objects in the Galaxy by mapping the central regions of the Milky Way; (3) study the non-thermal radiation in young supernova remnants, both the hard X-ray continuum and the emission from the radioactive element ^(44)Ti; (4) observe blazars contemporaneously with ground-based radio, optical, and TeV telescopes, as well as with Fermi and Swift, to constrain the structure of AGN jets; and (5) observe line and continuum emission from core-collapse supernovae in the Local Group, and from nearby Type Ia events, to constrain explosion models. During its baseline two-year mission, NuSTAR will also undertake a broad program of targeted observations. The observatory consists of two co-aligned grazing-incidence X-ray telescopes pointed at celestial targets by a three-axis stabilized spacecraft. Deployed into a 600 km, near-circular, 6° inclination orbit, the observatory has now completed commissioning, and is performing consistent with pre-launch expectations. NuSTAR is now executing its primary science mission, and with an expected orbit lifetime of 10 yr, we anticipate proposing a guest investigator program, to begin in late 2014.

/pdf/the-nuclear-spectroscopic-telescope-array-nustar-high-energy-2oznujlfte.pdf

THE NUCLEAR SPECTROSCOPIC TELESCOPE ARRAY (NuSTAR) HIGH-ENERGY X-RAY MISSION

CO line emission represents the most accessible and widely used tracer of the molecular interstellar medium. This renders the translation of observed CO intensity into total H2 gas mass critical to understand star formation and the interstellar medium in our Galaxy and beyond. We review the theoretical underpinning, techniques, and results of efforts to estimate this CO-to-H2 “conversion factor,” XCO, in different environments. In the Milky Way disk, we recommend a conversion factor XCO = 2×10 20 cm −2 (K km s −1 ) −1 with ±30% uncertainty. Studies of other “normal galaxies” return similar values in Milky Way-like disks, but with greater scatter and systematic uncertainty. Departures from this Galactic conversion factor are both observed and expected. Dust-based determinations, theoretical arguments, and scaling relations all suggest that XCO increases with decreasing metallicity, turning up sharply below metallicity ≈ 1/3–1/2 solar in a manner consistent with model predictions that identify shielding as a key parameter. Based on spectral line modeling and dust observations, XCO appears to drop in the central, bright regions of some but not all galaxies, often coincident with regions of bright CO emission and high stellar surface density. This lower XCO is also present in the overwhelmingly molecular interstellar medium of starburst galaxies, where several lines of evidence point to a lower CO-to-H2 conversion factor. At high redshift, direct evidence regarding the conversion factor remains scarce; we review what is known based on dynamical modeling and other arguments. Subject headings: ISM: general — ISM: molecules — galaxies: ISM — radio lines: ISM

/pdf/the-co-to-h2-conversion-factor-26tvppkvj7.pdf

The CO-to-H2 Conversion Factor

Excitons, electron-hole pairs in semiconductors, can be utilized as information carriers with a spin or valley degree of freedom. However, manipulation of excitons' motion is challenging because of their charge-neutral characteristic and short recombination lifetimes. Here we demonstrate electric-field-driven drift and funneling of charged excitons (i.e., trions) toward the center of a MoSe2 monolayer. Using a simple bottom-gate device, we control the electric fields in the vicinity of the suspended monolayer, which increases the trion density and pulls down the layer. We observe that locally excited trions are subjected to electric force and, consequently, drift toward the center of the stretched layer. The exerting electric force on the trion is estimated to be 102-104 times stronger than the strain-induced force in the stretched monolayer, leading to the successful observation of trion drift under continuous-wave excitation. Our findings provide a new route for manipulating trions and achieving new types of optoelectronic devices.

Electric-Field-Driven Trion Drift and Funneling in MoSe2 Monolayer.

The Gestalt psychologists were fascinated with dynamics evident in visual perception, and they theorized that these dynamics were attributable to ever-changing electrical potentials within topographically organized brain fields. Dynamic field theory, as it was called, was subsequently discredited on grounds that the brain does not comprise a unitary electrical field but, instead, a richly interconnected network of discrete computing elements. Still, this modern conceptualization of brain function faces the challenge of explaining the fact that perception is dynamic in space and in time. To pursue the question of visual perception and cortical dynamics, we have focused on spatio-temporal transitions in dominance during binocular rivalry. We have developed techniques for initiating and measuring these transitions psychophysically and for measuring their neural concomitants using functional magnetic resonance imaging (fMRI). Our findings disclose the existence of waves of cortical activity that travel across the retinotopic maps that define primary and secondary visual areas within occipital cortex, in correspondence with the subjective perception of spreading waves of dominance during binocular rivalry. This paper reviews the results from those studies.

/pdf/binocular-rivalry-and-neural-dynamics-3ybak8n1la.pdf

Binocular rivalry and neural dynamics

Our perception is often attracted to what we have seen before, a phenomenon called ‘serial dependence (SD).’ From a normative standpoint, SD can help us maintain a stable perception of the world by considering the statistical regularity in the environment. To serve this presumed normative function, SD must occur more strongly between consecutive elements sharing the same identity than between those with different identities when multiple elements undergo dynamic shifts in position across successive views. However, what factors contribute to such selective SD between identity-matching elements in dynamic situations remains unknown. Here, we hypothesized that SD preferentially occurs between consecutive elements matched in relative rather than absolute space because spatial correspondence in relative coordinates can warrant identity matching invariantly to changes in absolute coordinates. To test this hypothesis, we developed a task where two targets change positions in unison between successive views. The results supported our hypothesis: SD was stronger when consecutive targets matched in relative coordinates than in absolute coordinates. Moreover, SD transmission in relative coordinates was spatially more specific than previously observed in absolute coordinates. The characteristics of SD we found here promote object-based perceptual stabilization over time in dynamic situations.

https://www.biorxiv.org/content/biorxiv/early/2023/06/27/2023.06.27.546681.full.pdf

Spatial correspondence in relative space regulates serial dependence

Direction tuning curves of motion adaptation in the visual cortex revealed by an event-related fMRI study

In this paper, we investigate symmetric properties of the multivariate p-adic invariant integral on Zp. From our investigation, we derive some interesting identities for the extended higher-order q-Bernoulli polynomials of the second kind.

Some identities of symmetry for the extended higher-order q-Bernoulli polynomials of the second kind

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