| Autor: |
Megardon G. Tandonnet C. Sumner P. Guillaume A. |
| Rok vydání: |
2015 |
| Zdroj: |
Frontiers Computational Neuroscience |
| DOI: |
10.3389/fncom.2015.00128/abstract |
| Popis: |
Dynamic Neural Field models (DNF) often use a kernel of connection with short range excitation and long range inhibition. This organization has been suggested as a model for brain structures or for artificial systems involved in winner take all processes such as saliency localization perceptual decision or target/action selection. A good example of such a DNF is the superior colliculus (SC) a key structure for eye movements. Recent results suggest that the superficial layers of the SC (SCs) exhibit relatively short range inhibition with a longer time constant than excitation. The aim of the present study was to further examine the properties of a DNF with such an inhibition pattern in the context of target selection. First we tested the effects of stimulus size and shape on when and where self maintained clusters of firing neurons appeared using three variants of the model. In each model variant small stimuli led to rapid formation of a spiking cluster a range of medium sizes led to the suppression of any activity on the network and hence to no target selection while larger sizes led to delayed selection of multiple loci. Second we tested the model with two stimuli separated by a varying distance. Again single none or multiple spiking clusters could occur depending on distance and relative stimulus strength. For short distances activity attracted toward the strongest stimulus reminiscent of well known behavioral data for saccadic eye movements while for larger distances repulsion away from the second stimulus occurred. All these properties predicted by the model suggest that the SCs or any other neural structure thought to implement a short range MH is an imperfect winner take all system. Although those properties call for systematic testing the discussion gathers neurophysiological and behavioral data suggesting that such properties are indeed present in target selection for saccadic eye movements. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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