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. 2014 Feb 10;111(8):3170–3175. doi: 10.1073/pnas.1310442111

Fig. 1.

Fig. 1.

Correlate of the irradiation illusion in visual thalamus and cortex. (A) Receptive fields of ON-center LGN cells are larger than receptive fields of OFF-center LGN cells when mapped in conditions that resemble the irradiation illusion (ON, light targets on dark background; OFF, dark targets on light background) (Upper). Likewise, ON subfields of V1 neurons are larger than OFF subfields of V1 neurons (Lower). Receptive field maps (Left and Middle) are shown for ON and OFF LGN cells that are retinotopically aligned and for ON and OFF visual responses of a V1 recording site. The distributions of receptive field size (Right) have been normalized by the maximum receptive field size measured. In this and the following figures, red color represents ON and blue represents OFF. (B) As in the irradiation illusion on gray background, differences in receptive field size disappear in LGN (Upper) and slightly reverse in V1 (Lower). (C) ON receptive field sizes are larger in the dark than on gray backgrounds (Upper circles, LGN; Lower crosses, V1). (D) OFF receptive field sizes are similar in light and gray backgrounds (Upper circles, LGN; Lower crosses, V1).