2,198 research outputs found
Unifying Large- and Small-Scale Theories of Coordination
Coordination is a ubiquitous feature of all living things. It occurs by virtue of informational coupling among component parts and processes and can be quite specific (as when cells in the brain resonate to signals in the environment) or nonspecific (as when simple diffusion creates a sourceâsink dynamic for gene networks). Existing theoretical models of coordinationâfrom bacteria to brains to social groupsâtypically focus on systems with very large numbers of elements (Nââ) or systems with only a few elements coupled together (typically N = 2). Though sharing a common inspiration in Natureâs propensity to generate dynamic patterns, both approaches have proceeded largely independent of each other. Ideally, one would like a theory that applies to phenomena observed on all scales. Recent experimental research by Mengsen Zhang and colleagues on intermediate-sized ensembles (in between the few and the many) proves to be the key to uniting large- and small-scale theories of coordination. Disorderâorder transitions, multistability, orderâorder phase transitions, and especially metastability are shown to figure prominently on multiple levels of description, suggestive of a basic Coordination Dynamics that operates on all scales. This unified coordination dynamics turns out to be a marriage of two well-known models of large- and small-scale coordination: the former based on statistical mechanics (Kuramoto) and the latter based on the concepts of Synergetics and nonlinear dynamics (extended HakenâKelsoâBunz or HKB). We show that models of the many and the few, previously quite unconnected, are thereby unified in a single formulation. The research has led to novel topological methods to handle the higher-dimensional dynamics of coordination in complex systems and has implications not only for understanding coordination but also for the design of (biorhythm inspired) computers
Multistability and metastability: understanding dynamic coordination in the brain
Multistable coordination dynamics exists at many levels, from multifunctional neural circuits in vertebrates and invertebrates to large-scale neural circuitry in humans. Moreover, multistability spans (at least) the domains of action and perception, and has been found to place constraints upon, even dictating the nature of, intentional change and the skill-learning process. This paper reviews some of the key evidence for multistability in the aforementioned areas, and illustrates how it has been measured, modelled and theoretically understood. It then suggests how multistabilityâwhen combined with essential aspects of coordination dynamics such as instability, transitions and (especially) metastabilityâprovides a platform for understanding coupling and the creative dynamics of complex goal-directed systems, including the brain and the brainâbehaviour relation
Reviewer-coerced citation: Case report, update on journal policy and suggestions for future prevention
A case was recently brought to the journalâs attention regarding a reviewer who had requested a large number of citations to their own papers as part of their review. After investigation of their most recent reviews, we found that in every review this reviewer requested an average of 35 citations be added, âź90\% of which were to their own papers and the remainder to papers that both cited them extensively and mentioned them by name in the title. The reviewerâs phrasing strongly suggested that inclusion of these citations would influence their recommendation to the editor to accept or reject the paper. The reviewer was unable to provide a satisfactory justification for these requests and Bioinformatics has therefore banned them as a reviewer. Our investigation also suggests that the reviewer has behaved similarly in reviewing for other journals. This case has alerted us to how the peer-review system is vulnerable to unethical behavior, and prompted us to clarify the journalâs policy on when it is appropriate for reviewers to request citations to their own work, and to suggest how some of the current weak points in the peer-review system can be mitigated, so that this behavior can be detected more quickly and efficiently
Quantum noise induced entanglement and chaos in the dissipative quantum model of brain
We discuss some features of the dissipative quantum model of brain in the
frame of the formalism of quantum dissipation. Such a formalism is based on the
doubling of the system degrees of freedom. We show that the doubled modes
account for the quantum noise in the fluctuating random force in the
system-environment coupling. Remarkably, such a noise manifests itself through
the coherent structure of the system ground state. The entanglement of the
system modes with the doubled modes is shown to be permanent in the infinite
volume limit. In such a limit the trajectories in the memory space are
classical chaotic trajectories.Comment: 14 page
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