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S L Armentrout

Publications and source records attributed to S L Armentrout.

2 recordsLinked to original sources

A neural model of cortical map reorganization following a focal lesion.

Neural models based on fairly simple assumptions have been able to account for topographic map formation in sensory cortex and the map reorganization that occurs following repetitive stimulation and deafferentation. The spontaneous reorganization that follows an acute focal cortical lesion, however, has not been modeled successfully. We have developed a computational model of cortex based on the hypothesis that cortical activation is distributed competitively. This model exhibited spontaneous reorganization following a focal cortical lesion and makes a testable prediction about the time course of that reorganization. We describe our model and the hypotheses upon which it is based, and examine some of the factors which influence post-lesion reorganization. We also demonstrate that the extent of post-lesion reorganization can be greatly improved through selective repetitive stimulation, suggesting a clinical rehabilitation technique that can be tried in an experimental setting for patients suffering sensory loss due to focal brain damage.

Animals↗

Minimizing complexity in cellular automata models of self-replication.

Understanding self-replication from an information processing perspective is important because, among other things, it can shed light on molecular mechanisms of biological reproduction and on prebiotic chemical evolution. Intuition, biological knowledge, and early computational models of self-replication all suggested that self-replication is an inherently complex process. In this paper we describe recent computational studies that challenge this viewpoint. We summarize our recent work with cellular automata models of simple yet non-trivial self-replicating structures called unsheathed loops. For example, one unsheathed loop consists of only six components and requires only 20 rules to specify the local intercomponent interactions needed to bring about replication. The implication of this work is that, when viewed as an emergent property of numerous local, concurrent interactions between components, self-replicating systems can be substantially simpler than is generally recognized.

Computer Simulation↗