Visual masking

Polat, Sterkin, and Yehezkel[2] went into great detail in explaining the effect of temporal matching between target input and lateral propagation of the mask.

[6][7][8] There are multiple theories surrounding the neural correlates of masking, but most of them agree on a few key ideas.

One problem with this model, as proposed by Macknik and Martinez-Conde,[9] is that it predicts masking to occur as a function of how far apart, temporally, the stimulus onset is.

However, Macknik and Martinez-Conde showed that backward masking is actually more dependent on how far apart stimulus termination is.

This model proposes that backward masking is caused by an interference with feedback from higher visual areas.

Lamme's group further supported their model when they described that the surgical removal of the extrastriate cortex in monkeys leads to a reduction of area V1 late responses.

Haynes, Driver, and Rees proposed this theory in 2005,[18] stating that visibility derives from the feed forward and feedback interactions between the V1 and fusiform gyrus.

In their experiment, they required subjects to attend actively to the target- thus, as Macknik and Martinez-Conde point out,[9] it is possible that their results were confounded by the attentional aspect of the trials, and that the results may not accurately reflect the effects of visual masking.

Macknik & Martinez-Conde[21] recorded from neurons in the lateral geniculate nucleus (LGN) and V1 V1 while presenting monoptic and dichoptic stimuli, and found that monoptic masking occurred in all the LGN and V1 neurons that were recorded, but dichoptic masking only occurred in some of the binocular neurons in V1, which supports the hypothesis that visual masking in monoptic regions is not due to feedback from dichoptic regions.

Thus, dichoptic masking must become stronger as it proceeds down the visual hierarchy if the preceding hypothesis is correct.