Neurobehavioral Changes in Macular Degeneration: Spatial Frequency Use in Scene Recognition.

Purpose: Central vision loss in macular diseases severely affects visual perception and cognition, particularly scene recognition. A key question is whether observed impairments result solely from reduced input or reflect functional changes in spatial frequency processing. This study investigated how macular diseases affects this processing at both behavioral and brain levels. Methods: We compared patients with macular diseases with age-matched controls using an artificial scotoma simulating each patient's central vision loss. Participants performed a scene categorization task with images filtered in high spatial frequencies (HSFs; fine details) or low spatial frequencies (LSFs; global shape). Patients fixated using their preferred retinal locus (PRL), whereas controls fixated on the location corresponding to the patient's fovea, within the artificial scotoma. Behavioral performance and functional magnetic resonance imaging (fMRI) responses were analyzed. Results: Patients performed worse than the healthy controls for both HSF and LSF scenes, with a more pronounced deficit for HSFs. These deficits were associated with reduced activation in occipital cortex and in the parahippocampal place area (PPA), particularly for HSF scenes. In contrast, LSF processing was relatively preserved and accompanied by increased recruitment of higher-level cognitive and oculomotor areas in patients. Conclusions: These findings demonstrate that macular diseases leads to altered spatial frequency processing within residual vision itself, particularly affecting fine-detail analysis. This perceptual degradation is accompanied by functional brain reorganization supporting partial compensation. The results highlight the importance of considering both degraded input and adaptive mechanisms when designing rehabilitation strategies based on residual peripheral vision.