Spatial updating

This two-dimensional model uses the same input signals, interactions, and concepts as the one-dimensional model proposed by Ziesche and Hamker.

In addition to the existing inputs, we expanded the model by including a fourth input signal to introduce top-down attention to the system.

In one type, spatial attention lingers after a saccade at the (irrelevant) retinotopic position—that is, the focus of attention appears to shift with the eyes but updates to its original world-centered position only after the eyes land at the saccade target location (Golomb, Chun, & Mazer, 2008; Golomb, Pulido, Albrecht, Chun, & Mazer 2010).

Another study by Rolfs, Jonikaitis, Deubel, & Cavanagh (2011) shows that shortly before saccade onset, a locus of attention appears at a position opposite to the direction of the saccade, which suggests an anticipatory correction of the effects of eye movements.

Third, as the (proprioceptive) eye-position signal is head centered but the corollary discharge is eye displacement—thus retinocentric—and both eye signals jointly contribute to the final decision, they are required to communicate with each other and operate in the same reference frame.

Our model can account for both types of updating of attention at a neural-systems level.The lingering effect originates from the late updating of the proprioceptive eye-position signal and the remapping from the early corollary-discharge signal.We put these results in relationship to predictive remapping of receptive fields and show that both phenomena arise from the same simple, recurrent neural circuit.Thus, together with the previously published results, the model provides a comprehensive framework for discussing multiple experimental observations that occur around saccades.During natural vision, scene perception depends on exploratory scanning using accurate targeting of attention, saccadic eye movements, anticipation of the physical consequences of motor actions, and continuous integration of visual inputs with stored representations of previously viewed portions of the scene.

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