Delay Compensation Through Facilitating Synapses and STDP: A Neural Basis for Orientation Flash-Lag Effect

In orientation flash-lag effect (FLE), a continuously rotating bar in the center is perceived to be misaligned toward the direction of rotation when compared to a briefly flashed pair of flanking bars that are actually aligned. The implication of this simple visual illusion is quite profound: The effect may be due to motion extrapolation, undoing the effects of neural conduction delay. Previously, we showed that facilitating synapses may be a neural basis of such a delay compensation mechanism in other forms of FLE such as luminance FLE. However, the approach based on a single neuron cannot be applied to orientation FLE since firing rate in a single neuron cannot represent the full range of orientations. Here, we extend our model to multiple neurons, and show that facilitating synapses, together with adaptation through Spike-Timing-Dependent Plasticity (STDP), can serve as a neural basis for delay compensation giving rise to orientation FLE.