Spontaneous recruitment of the person-knowledge network by familiar voices in the congenitally blind.

Recognising a familiar individual involves the spontaneous retrieval of person-specific information, engaging a distributed cortical network for person knowledge. While the role of this system is well established for visual face perception, it remains unclear whether its recruitment depends on visual experience. Here, we investigated the neural basis of voice-identity processing in congenitally blind and sighted individuals using fMRI. Participants listened to personally familiar and unfamiliar voices while performing an identity recognition task. Familiar voices elicited stronger responses across groups in the temporoparietal junction (TPJ), medial prefrontal cortex (mPFC), and right middle temporal gyrus. Of these, the TPJ and anterior mPFC-regions typically implicated in the network for person knowledge-showed a more pronounced familiarity effect in congenitally blind participants than in sighted controls. Multivariate analysis further revealed stronger identity-specific representations in the blind in the right TPJ, adjacent to the region showing enhanced univariate responses, as well as in the left intraparietal sulcus. These findings demonstrate that voice-identity cues alone can drive spontaneous access to person knowledge in the absence of visual input in both the normally sighted and the blind, but engagement of this network is stronger in the blind. These results indicate that the network for person knowledge develops in a modality-flexible manner shaped by the social demands of interpersonal interaction.