The Neural Organization of Visual Information in the Auditory Cortex of the Congenitally Deaf
Temas
Detalles
Neuroplasticity is the brain's ability to reorganize its structural and functional architecture throughout life. In congenital deafness, the sensory-deprived auditory cortex can be recruited to represent sensory information belonging to other modalities, a process known as cross-modal plasticity. Previous studies have indicated that the auditory cortex of congenitally deaf, but not of hearing individuals, is recruited during visual tasks. However, it remains unclear whether and to what extent these cross-modal responses represent low-level visual spatial information or map the visual field. Here, we addressed this question using two complementary fMRI experiments focusing on cross-modal processing in the auditory cortex of both deaf and hearing individuals during passive viewing of conventional visual stimuli. The first experiment, at the group level, revealed that, unlike in hearing individuals, the auditory cortex of deaf individuals predominantly exhibited negative BOLD signals in early and associative auditory areas—a surprising finding given the prevailing focus on activations in prior work. These negative BOLD signals—commonly interpreted as deactivation responses—suggest that visual information may be represented via cross-modal deactivation mechanisms. We complement the investigation with an exploratory follow-up analysis using pRF modeling in a subset of participants. Together, our findings indicated that, in congenitally deaf individuals, cross-modal visual processing in the auditory cortex may be mediated by deactivation signals, offering new insights into the neural basis of sensory reorganization.