Sang Wook Hong^1,2 (), Yosun Yoon^1,2; ¹Department of Psychology, Florida Atlantic University, ²Stiles-Nicolson Brain Institute, Florida Atlantic University

When asked to visualize a large red apple, most people can effortlessly generate a vivid mental image. In contrast, individuals with aphantasia report being unable to voluntarily produce such visual imagery (Zeman et al., 2015). A central question is whether aphantasia reflects a failure to form neural representations of imagined content, or instead a disruption in conscious access to otherwise intact representations. The present study addressed this question using fMRI combined with multivariate pattern analysis (MVPA). Four participants (three with aphantasia) completed four scanning sessions over a two-week period: (1) retinotopy and localizer, (2) orientation decoding of visually presented gratings, (3) decoding of orientation held in working memory, and (4) decoding of visually imagined orientation. The working-memory task followed Harrison & Tong (2008): two oriented gratings (200 ms each) were presented sequentially, followed by a cue indicating which orientation to retain during an 11-s delay. In the imagery condition, gratings were replaced with double-sided arrows, and participants were instructed to imagine a full-field grating of the indicated orientation. Across all participants—including those with aphantasia—MVPA reliably discriminated orientation-specific activity patterns in early visual cortex for (1) viewed gratings, (2) remembered gratings, and (3) imagined gratings. These findings indicate that individuals with aphantasia do form decodable sensory-like representations during imagery, suggesting that the condition may reflect a disruption of phenomenological experience rather than a lack of underlying neural representation.

Acknowledgements: Stiles-Nicolson Brain Institute, Florida Atlantic University