Spatial remapping without gain fields: a neural model based on cortico-thalamic connectivity B Babadi1, N Jia2, P Safari3, A Yazdanbakhsh2 |
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1Center for Brain Science, Harvard University, MA, United States |
| Experimental evidence has identified neurons in the frontal eye field (FEF) whose receptive fields undergo dynamic changes prior to saccade, such that their spatial profile is altered to compensate for saccadic eye movement. It has been long suggested that the receptive field shifts in areas such as FEF can be accomplished by modulation of neuronal gains. However, there is little experimental support for changes in the gain of neuronal responses in such conditions. Besides, implementing such algorithms in real neural substrate is not straightforward. In this work we propose an alternative biologically plausible mechanism for spatial remapping of receptive fields using simple linear-nonlinear neurons with fixed nonlinearity and synaptic connectivity. Based on universal approximation theorem, we show that a modulation in neural gain can be implemented by a neural model with fixed synaptic weights based on the connectivity patterns among the most involved areas in eye movement and receptive field remapping, namely superior colliculus, medial dorsal nucleus of thalamus, and FEF. Numerical simulations confirm the performance of such a model for a wide range of conditions, corresponding to neurophysiological results. The extensions of our results to sensory-motor mapping in other brain areas and implementation of attentional gain fields are discussed. |
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