Spatial pooling inherent to intrinsic signal optical imaging might cause V2 to resemble a solution to the stereo correspondence problem

Using intrinsic signal optical imaging, Chen et al. (1) show that disparity information in visual area V2 is decodable from correlated random dot stereograms (cRDSs), but not from anticorrelated RDSs (aRDSs). The authors conclude that “V2 is the initial locus of false matching elimination,” indicating that the correspondence problem is solved within or immediately after V2. We disagree with this conclusion based on previous single-unit studies. Two immediate downstream areas of V2, middle temporal area (MT) and V4, still encode disparities of aRDSs. Anticorrelation reduces the disparity selectivity by only ∼50% in MT (2, 3) and ∼60% in V4 (3, 4) (as evaluated by the mean amplitude ratio between the tuning curves for aRDSs and cRDSs). These findings suggest … [↵][1]1To whom correspondence should be addressed. Email: fujita{at}fbs.osaka-u.ac.jp. [1]: #xref-corresp-1-1