Multi-level reorganization in the temporal dynamics of sound processing in early blind people

Poster Session E - Monday, April 15, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Siddharth Talwar¹ (siddharthtalwar0309@gmail.com), Mattioni Stefania², Eleonore Giraudet¹, Calce Roberta P.¹, Barbero Francesca M.¹, Collignon Olivier^1,3; ¹Institute for research in Psychology (IPSY) & Neuroscience (IoNS), Louvain Bionics, University of Louvain (UCLouvain), Louvain, Belgium, ²Department of Experimental Psychology; UGent, Gent, Belgium, ³HES-SO Valais-Wallis, School of Health Sciences; The Sense Innovation and Research Center, Lausanne and Sion, Switzerland

Early blindness triggers reorganization in brain networks that code for sound processing. How visual deprivation impacts the temporal dynamics of different stages of auditory discrimination (acoustic to categorical coding) remains unexplored. We used electroencephalography (EEG) to characterize the time course of brain representation elicited by sounds belonging to eight categories in congenitally blind (CB) and sighted individuals (SC). Multivariate decoding analyses revealed enhanced sound decoding in CB from ~160 to 1000ms after sound onset. Classifier weights transformed and projected on the sensors were enhanced in CB with the topography evolving along a fronto-posterior axis as the sound unfolded in time. To investigate which formats of sound processing were enhanced in CB, we used representational similarity analysis (RSA) with different sound models: (I) Modulation Transfer Function (MTF) simulating early stage of acoustic processing, (ii) layers of a deep neural network (DNN-YAMNET), (iii) models based on categorical membership of sounds and participant specific similarity ratings of each sound pairs. MTF model peaked at ~200ms in the EEG of each group, with no differences between the two populations. Correlations between brain activity and specific DNN layers were enhanced in CB at ~200ms and sound offset likely representing modulations in intermediate acoustic processing. Categorical representation of sounds emerged at ~250ms in both groups, with CB showing an enhanced representation peaking at ~550ms. These results suggest that early blindness triggers a multi-level reorganization in brain networks coding for sounds, with enhanced intermediate-level acoustic discrimination earlier in time, followed by an increased categorical coding of sounds.

Topic Area: PERCEPTION & ACTION: Audition