Journal of the International Neuropsychological Society

Regular Articles

Establishing, versus Maintaining, Brain Function: A Neuro-computational Model of Cortical Reorganization after Injury to the Immature Brain

Sreedevi Variera1, Marcus Kaisera1a2a3 and Rob Forsytha2 c1

a1 School of Computing Science, Newcastle University, Newcastle upon Tyne, United Kingdom

a2 Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom

a3 Department of Brain and Cognitive Sciences, Seoul National University, Korea

Abstract

The effect of age at injury on outcome after acquired brain injury (ABI) has been the subject of much debate. Many argue that young brains are relatively tolerant of injury. A contrasting viewpoint due to Hebb argues that greater system integrity may be required for the initial establishment of a function than for preservation of an already-established function. A neuro-computational model of cortical map formation was adapted to examine effects of focal and distributed injury at various stages of development. This neural network model requires a period of training during which it self-organizes to establish cortical maps. Injuries were simulated by lesioning the model at various stages of this process and network function was monitored as “development” progressed to completion. Lesion effects are greater for larger, earlier, and distributed (multifocal) lesions. The mature system is relatively robust, particularly to focal injury. Activities in recovering systems injured at an early stage show changes that emerge after an asymptomatic interval. Early injuries cause qualitative changes in system behavior that emerge after a delay during which the effects of the injury are latent. Functions that are incompletely established at the time of injury may be vulnerable particularly to multifocal injury. (JINS, 2011, 17, 1030–1038)

(Received November 18 2010)

(Revised June 28 2011)

(Accepted June 28 2011)

Keywords

  • Neuronal plasticity;
  • Simulation;
  • Recovery of function;
  • Cerebral cortex;
  • Child development;
  • Neural networks

Correspondence:

c1 Correspondence and reprint requests to: Rob Forsyth, Institute of Neuroscience, Newcastle University, Sir James Spence Building, Royal Victoria Infirmary, Newcastle upon Tyne, NE1 4LP, United Kingdom. E-mail: rob.forsyth@newcastle.ac.uk

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