Dwelling Quietly in the Rich Club: Brain Network Determinants of Slow Cortical Fluctuations

For more than a century, cerebral cartography has been driven by investigations of structural and morphological properties of the brain across spatial scales and the temporal/functional phenomena that emerge from these underlying features. The next era of brain mapping will be driven by studies that consider both of these components of brain organization simultaneously -- elucidating their interactions and dependencies. Using this guiding principle, we explored the origin of slowly fluctuating patterns of synchronization within the topological core of brain regions known as the rich club, implicated in the regulation of mood and introspection. We find that a constellation of densely interconnected regions that constitute the rich club (including the anterior insula, amygdala, and precuneus) play a central role in promoting a stable, dynamical core of spontaneous activity in the primate cortex. The slow time scales are well matched to the regulation of internal visceral states, corresponding to the somatic correlates of mood and anxiety. In contrast, the topology of the surrounding "feeder" cortical regions show unstable, rapidly fluctuating dynamics likely crucial for fast perceptual processes. We discuss these findings in relation to psychiatric disorders and the future of connectomics.Comment: 35 pages, 6 figure

Introduction

This chapter will motivate why it is useful to consider the topic of derivations and filtering in more detail. We will argue against the popular belief that the minimalist program and optimality theory are incompatible theories in that the former places the explanatory burden on the generative device (the computational system) whereas the latter places it on the fi ltering device (the OT evaluator). Although this belief may be correct in as far as it describes existing tendencies, we will argue that minimalist and optimality theoretic approaches normally adopt more or less the same global architecture of grammar: both assume that a generator defines a set S of potentially well-formed expressions that can be generated on the basis of a given input and that there is an evaluator that selects the expressions from S that are actually grammatical in a given language L. For this reason, we believe that it has a high priority to investigate the role of the two components in more detail in the hope that this will provide a better understanding of the differences and similarities between the two approaches. We will conclude this introduction with a brief review of the studies collected in this book.

Early Warning Analysis for Social Diffusion Events

There is considerable interest in developing predictive capabilities for social diffusion processes, for instance to permit early identification of emerging contentious situations, rapid detection of disease outbreaks, or accurate forecasting of the ultimate reach of potentially viral ideas or behaviors. This paper proposes a new approach to this predictive analytics problem, in which analysis of meso-scale network dynamics is leveraged to generate useful predictions for complex social phenomena. We begin by deriving a stochastic hybrid dynamical systems (S-HDS) model for diffusion processes taking place over social networks with realistic topologies; this modeling approach is inspired by recent work in biology demonstrating that S-HDS offer a useful mathematical formalism with which to represent complex, multi-scale biological network dynamics. We then perform formal stochastic reachability analysis with this S-HDS model and conclude that the outcomes of social diffusion processes may depend crucially upon the way the early dynamics of the process interacts with the underlying network's community structure and core-periphery structure. This theoretical finding provides the foundations for developing a machine learning algorithm that enables accurate early warning analysis for social diffusion events. The utility of the warning algorithm, and the power of network-based predictive metrics, are demonstrated through an empirical investigation of the propagation of political memes over social media networks. Additionally, we illustrate the potential of the approach for security informatics applications through case studies involving early warning analysis of large-scale protests events and politically-motivated cyber attacks

Notes on cartography and further explanation

This article addresses one particular aspect of the cartographic enterprise, the cartographic study of the left periphery of the clause, the system of criteria, and the "syntacticisation” of scope-discourse semantics that rich and detailed syntactic maps make possible. I will compare this theoretical option with the conceivable alternative, the "pragmaticization” of a radically impoverished syntax, and will discuss some simple kinds of empirical evidence bearing on the choice between these alternative perspectives. I will then turn to the issue of whether the properties of the functional sequence (ordering, cooccurrence restrictions) are amenable to "further explanations” in terms of more basic principles constraining linguistic computations. I will argue that the search for deeper explanations is an integral part of the cartographic endeavour: it presupposes the establishment of reliable maps, and nourishes the pursuit of further cartographic questions. I will conclude by illustrating the issue of further explanation by comparing certain properties of topicalization in English and Italian, in particular the fact that DP topics are fundamentally unique in English, while they can be freely reiterated in Italian. This pattern can be plausibly traced back to intervention locality, once certain independent properties distinguishing Italian and English topicalization are taken into accoun

The logic of organizational markets: thinking through resource partitioning theory

Resource partitioning theory claims that Increasing concentration enhances the life chances of specialist organizations. We systemati- cally think through this theory,specify implicit background assump- tions,sharpen concepts,and rigorously check the theory s logic.As a result,we increase the theory s explanatory power,and claim contrary to received opinion that under certain eneral conditions, resource partitioning and the proliferation of specialists can take place independently of organizational mass and relative size effects, size localized competition,diversifying consumer tastes, increasing number of dimensions of the resource space,and changing niche widths. Our analysis makes furthermore clear that specialist and generalist strategies are asymmetric, and shows that not concentration enhances the life chances of specialists but economies of scale instead.Under the conditions explicated,we argue that if scale economies come to dominate,the number of organizations in the population increases, regardless of the incumbents sizes.

(WP 2018-04) Economics and Economic Methodology in a Core-Periphery Economic World

This paper uses a core-periphery distinction to characterize contemporary economics, economic methodology, and also today’s world economy. First, it applies the distinction to the organization of contemporary economics through an examination of the problem of explaining economics’ relations to and boundaries with other disciplines. Second, it argues that economics’ core-periphery organization is replicated in a similar organization of the use and practice of contemporary economic methodology in economics Third, it draws on the use of the core-periphery thinking in economics itself and the uneven development of the world economy to provide possible foundations for economics and economic methodology being organized in core-periphery terms. Fourth, the paper briefly discusses three as a potential countervailing forces operating on the development of contemporary economics that might work against its core-periphery organization

On Folding and Twisting (and whatknot): towards a characterization of workspaces in syntax

Syntactic theory has traditionally adopted a constructivist approach, in which a set of atomic elements are manipulated by combinatory operations to yield derived, complex elements. Syntactic structure is thus seen as the result or discrete recursive combinatorics over lexical items which get assembled into phrases, which are themselves combined to form sentences. This view is common to European and American structuralism (e.g., Benveniste, 1971; Hockett, 1958) and different incarnations of generative grammar, transformational and non-transformational (Chomsky, 1956, 1995; and Kaplan & Bresnan, 1982; Gazdar, 1982). Since at least Uriagereka (2002), there has been some attention paid to the fact that syntactic operations must apply somewhere, particularly when copying and movement operations are considered. Contemporary syntactic theory has thus somewhat acknowledged the importance of formalizing aspects of the spaces in which elements are manipulated, but it is still a vastly underexplored area. In this paper we explore the consequences of conceptualizing syntax as a set of topological operations applying over spaces rather than over discrete elements. We argue that there are empirical advantages in such a view for the treatment of long-distance dependencies and cross-derivational dependencies: constraints on possible configurations emerge from the dynamics of the system.Comment: Manuscript. Do not cite without permission. Comments welcom