4,274 research outputs found
Molecular self-organisation in a developmental model for the evolution of large-scale artificial neural networks
We argue that molecular self-organisation during embryonic development allows evolution to perform highly nonlinear combinatorial optimisation. A structured approach to architectural optimisation of large-scale Artificial Neural Networks using this principle is presented. We also present simulation results demonstrating the evolution of an edge detecting retina using the proposed methodology
On Reverse Engineering in the Cognitive and Brain Sciences
Various research initiatives try to utilize the operational principles of
organisms and brains to develop alternative, biologically inspired computing
paradigms and artificial cognitive systems. This paper reviews key features of
the standard method applied to complexity in the cognitive and brain sciences,
i.e. decompositional analysis or reverse engineering. The indisputable
complexity of brain and mind raise the issue of whether they can be understood
by applying the standard method. Actually, recent findings in the experimental
and theoretical fields, question central assumptions and hypotheses made for
reverse engineering. Using the modeling relation as analyzed by Robert Rosen,
the scientific analysis method itself is made a subject of discussion. It is
concluded that the fundamental assumption of cognitive science, i.e. complex
cognitive systems can be analyzed, understood and duplicated by reverse
engineering, must be abandoned. Implications for investigations of organisms
and behavior as well as for engineering artificial cognitive systems are
discussed.Comment: 19 pages, 5 figure
Oscillations, metastability and phase transitions in brain and models of cognition
Neuroscience is being practiced in many different forms and at many different organizational levels of the Nervous System. Which of these levels and associated conceptual frameworks is most informative for elucidating the association of neural processes with processes of Cognition is an empirical question and subject to pragmatic validation. In this essay, I select the framework of Dynamic System Theory. Several investigators have applied in recent years tools and concepts of this theory to interpretation of observational data, and for designing neuronal models of cognitive functions. I will first trace the essentials of conceptual development and hypotheses separately for discerning observational tests and criteria for functional realism and conceptual plausibility of the alternatives they offer. I will then show that the statistical mechanics of phase transitions in brain activity, and some of its models, provides a new and possibly revealing perspective on brain events in cognition
Bridging scales in cancer progression: Mapping genotype to phenotype using neural networks
In this review we summarize our recent efforts in trying to understand the
role of heterogeneity in cancer progression by using neural networks to
characterise different aspects of the mapping from a cancer cells genotype and
environment to its phenotype. Our central premise is that cancer is an evolving
system subject to mutation and selection, and the primary conduit for these
processes to occur is the cancer cell whose behaviour is regulated on multiple
biological scales. The selection pressure is mainly driven by the
microenvironment that the tumour is growing in and this acts directly upon the
cell phenotype. In turn, the phenotype is driven by the intracellular pathways
that are regulated by the genotype. Integrating all of these processes is a
massive undertaking and requires bridging many biological scales (i.e.
genotype, pathway, phenotype and environment) that we will only scratch the
surface of in this review. We will focus on models that use neural networks as
a means of connecting these different biological scales, since they allow us to
easily create heterogeneity for selection to act upon and importantly this
heterogeneity can be implemented at different biological scales. More
specifically, we consider three different neural networks that bridge different
aspects of these scales and the dialogue with the micro-environment, (i) the
impact of the micro-environment on evolutionary dynamics, (ii) the mapping from
genotype to phenotype under drug-induced perturbations and (iii) pathway
activity in both normal and cancer cells under different micro-environmental
conditions
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