Poster D115, Monday, March 27, 8:00 – 10:00 am, Pacific Concourse
Mapping the acoustical and categorical features of sounds in the occipital cortex of blind and sighted people
Stefania Mattioni1,2, Rezk Mohamed2, Karen Cuculiza1, Ceren Battal1, Roberto Bottini1, Markus Van Ackeren1, Nick Oosterhof1, Olivier Collignon1,2; 1University of Trento, Italy, 2Université catholique de Louvain, Louvain-la-Neuve, Belgium
It has recently been proposed that regions of the ventral occipital-temporal cortex (VOTC), previously considered purely visual, are in fact showing preference toward specific categories independently of the sensory input. Moreover, this functional architecture may develop in the absence of visual experience since studies have shown similar response profile of VOTC in early blind people. In this study, we relied on representational similarity analysis of fMRI data in order to link similarities of brain activity patterns with different features similarities of either visual (in sighted only) or sound (in sighted and blind) stimuli space. In sighted, only posterior middle temporal gyrus (pMTG) demonstrated a similar coding of auditory and visual categories (eg. animate-inanimate) bringing limited support to the idea that most of VOTC is abstracted from the sensory input. We also observed that the occipital cortex of blind individuals shows enhanced coding of both sound categories (animate-inanimate) and physical properties (pitch) of the acoustical stimuli. However, no postero-anterior gradient was observed for the coding of low- versus high-level features of sounds, showing that the hierarchical architecture of the occipital cortex is not preserved for acoustic processing in the blind. Additional analyses of the stability of the pattern of brain activity elicited by sound stimuli showed that early visual deprivation triggers a large-scale imbalance between occipital and temporal regions. Together, these results suggest that VOTC shows a strong sensory tuning toward visual stimuli in the sighted and reorganize to enhance its response toward non-visual input in case of early visual deprivation.
Topic Area: PERCEPTION & ACTION: Other