Synaptic rewiring for topographic mapping and receptive field development.
A model of topographic map refinement is presented which combines both weight plasticity and the formation and elimination of synapses, as well as both activity-dependent and activity-independent processes. The question of whether an activity-dependent process can refine a mapping created by an activity-independent process is addressed statistically. A new method of evaluating the quality of topographic projections is presented which allows independent consideration of the development of the centres and spatial variances of receptive fields for a projection. Synapse formation and elimination embed in the network topology changes in the weight distributions of synapses due to the activity-dependent learning rule used (spike-timing-dependent plasticity). In this model, the spatial variance of receptive fields can be reduced by an activity-dependent mechanism with or without spatially correlated inputs, but the accuracy of receptive field centres will not necessarily improve when synapses are formed based on distributions with on-average perfect topography.
Bamford
Simeon A
SA
Doctoral Training Centre for Neuroinformatics and Computational Neuroscience, University of Edinburgh, Edinburgh, United Kingdom. simeon.bamford@iss.infn.it
Murray
Alan F
AF
Willshaw
David J
DJ
D008959:Models, Neurological; D009415:Nerve Net / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology