Tuning to Y-like figures in the cat striate neurons

Sensitivity to symmetric or asymmetric Y-like figures and crosses of differ ent shapes and orientations flashed in the receptive field was studied in 1 01 neurons of the cat striate cortex (area 17) and compared with their orie ntation tuning to a single light bar. Selective sensitivity to the Y-like f igure (figure/bar response ratio more than 1.25) was found in 78/101 neuron s (77.2% of cases) and to the cross-in 54/101 units (53.4%). In 62.5% of ne urons with sensitivity to both figures, sensitivity to the Y-like figure wa s higher than to a cross. Tuning to Y-like figure was typically (60%) selec tive to both its shape and orientation. The remaining Y-like selective neur ons exhibited invariant tuning to orientation and/or shape of the figure. T he preferred angles between two lines of Y-like figures were distributed in the range of 22.5-157.5 degrees with slight preference to 90 degrees, whil e crosses of 45 degrees and 90 degrees angles were preferable. Response mag nitudes to a single bar, a Y-like figure and a cross were positively correl ated. Possible mechanisms and functional implication of the striate sensiti vity to Y-like figures are discussed, (C) 2001 Elsevier Science Inc.