eLife Assessment
This study presents an important finding regarding a significant, understudied question: How does adaptation affect spatial frequency processing in the human visual cortex? Using both psychophysics and neuroimaging the authors conclude that adaptation induces changes in perceived spatial frequency and population receptive field size (pRF) size, depending on the adaptation state. Specifically, adapting to a low spatial frequency increases perceived spatial frequency and results in smaller pRFs, whereas adapting to a high spatial frequency decreases perceived spatial frequency and leads to broader pRFs. These results offer an explanation for previous seemingly conflicting findings regarding the effects of adaptation on size illusions and the evidence is solid; however, including a clear, direct comparison between pRF sizes in the high-adapted and low-adapted conditions would further strengthen the argument.