In a recent study, facial features were visible to blind individuals due to an apparatus that converts photos into sound waves.
Scientists at Georgetown University Medical Center outlined the foundation for hearing and visual compensation. Published in PLOS ONE, the findings provide fresh insights into the brain regions involved in facial recognition and processing.
We used a technology called' sensory substitution' that transforms visual shapes into sounds by means of a computer chip.
- Josef P. Rauschecker, co-author
Ten sighted individuals and six blind people were recruited as a cohort.
The cohort listened to sound waves created by the device that translated their facial characteristics into audio waves.
It took some time for the participants to pick up on the "sound" of geometric forms, which were combined to create more intricate symbols representing faces. In the end, the training proved to be effective.
Sensory substitution and its link with facial recognition
All blind participants, according to Rauschecker, were able to grasp the task and recognize the faces more than 85% of the time.
The subjects' brains were scanned three times using magnetic resonance imaging (MRI) throughout this procedure.
As a result, the authors could observe which brain regions were active when they listened to the "faces." Previous research has linked face recognition to several different brain regions.
The novel findings refute the notion by scientists that this process is so crucial to socialization that the brain wiring enabling it must be either innate or dependent on infants being exposed to visual face information.
To our surprise, one of the major nodes in the brain's face recognition network, the fusiform face area (FFA), lit up, but on the opposite side of the brain from where it would light up in sighted people.
- Rauschecker
The researchers think this discrepancy might be explained by the two sides of the FFA playing distinct functions, with one side handling linked patterns in face data and the other operating individual components.
The results imply that exposure to facial expression geometry and contours—rather than a particular visual input—is essential to the FFA's functionality.
Researchers from Johns Hopkins University and the University of Cambridge indicate in an eLife publication that plasticity functions by merely turning on abilities that are latent in the new brain region, as opposed to rewiring talents from one brain area to another.
Even while the "rewiring" idea of plasticity is still widely accepted, Rauschecker admitted that the results of his team's research lend weight to both viewpoints.
He notes that another possibility is that, independent of sensory modality, the neurons in the FFA are tuned to the geometry of face combinations. Put another way, FFA neurons can already react to touch and sound; the appropriate method is all that is needed to bring it out.
Rauschecker concludes that the team is optimistic that new technologies can be created to capitalize on this flexibility and help us create tools to restore vision to blind people.
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