Figure 5: Simulations of neural field model. | Nature Communications

Figure 5: Simulations of neural field model.

From: Variability in visual cortex size reflects tradeoff between local orientation sensitivity and global orientation modulation

Figure 5

We simulated the model using stimuli similar to the ones used in our psychophysical experiments. (a) To quantify the model’s visual discrimination sensitivity, we simulated it with a set of stimuli that differed in only a single feature (orientation, contrast, luminance and visual field location). The activation pattern of the model visual cortex was compared for different stimuli along each feature dimension, where the degree of overlap in activation pattern decreased with the feature difference between stimuli. The feature difference at the threshold point where the activation overlap decreased to 50% was quantified as the model’s visual discrimination threshold. (b) To quantify the model’s contextual modulation magnitude, we simulated it with contextual illusion stimuli where a central circular stimulus was surrounded by a surrounding annular stimulus. The response of model neurons to the central stimulus was modulated by the response of their neighbouring neurons to the surrounding stimulus, where the inhibitory connections from neighbouring neurons caused a repulsive shift in the model’s response to the central stimulus (from black to grey line). The extent of this shift was quantified as the model’s contextual modulation magnitude.

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