Haowen Guan¹, Min Guo², Yaou Liu², Sheng He¹; ¹Institute of Biophysics, University of Chinese Academy of Sciences, ²Tiantan Hospital, Capital Medical University

Radiologists’ expert-level performance in detecting abnormalities in chest X-rays could be supported by holistic processing, a mechanism exemplified in face recognition. Visual areas such as the fusiform face area (FFA) and occipital face area (OFA), as indicated by their names, have been considered to be specialized in face processing, their role in holistic processing associated with visual expertise remains unclear. This study investigates the involvement of holistic processing when radiologists performed visual recognition tasks. Behavioural and 3T fMRI experiments were conducted with radiologists and laypersons. Participants viewed three types of images (faces, buildings, chest x-rays) with the images presented in two modes (upright vs. inverted and amodally completed vs. uncompleted), to modulate the degree of holistic processing. Behavioural results confirmed that radiologists rely on holistic strategies when interpreting chest X-rays. Multivariate pattern analysis (MVPA) of the fMRI data revealed that when holistic processing was disrupted, radiologists' decoding accuracy for X-rays versus buildings significantly decreased in the left FFA (lFFA) and left OFA (lOFA), suggesting that these regions encode expertise-specific holistic information. Furthermore, the right FFA (rFFA) showed improved decoding accuracy for inverted faces and stronger category selectivity for faces over buildings in radiologists, suggesting that radiological expertise modulates neural responses to stimuli that rely on holistic processing, regardless of whether the expertise for the images was professionally acquired or not. These results demonstrate that the lFFA and lOFA are central to the encoding of holistic information in radiological expertise, whereas radiological training also enhanced the rFFA’s existing sensitivity to faces. This study advances our understanding of the neural basis of expert perceptual processing and its relationship to holistic mechanisms.