News release

From: Society for Neuroscience

Neural and Behavioral Correlates of Evidence Accumulation in Human Click-Based Echolocation

Researchers linked neural activity to how blind individuals determine the location of objects by integrating echoes from mouth clicks into a representation of their surroundings.

Some blind people use returning echoes from their own mouth clicks to perceive external surroundings, or echolocation. Haydee Garcia Lazaro and Santani Teng, from Smith–Kettlewell Eye Research Institute, explored how the human brain creates representations of external surroundings using echolocation.

The researchers first discovered that four blind individuals comfortable with using echolocation could identify object location better than 21 people with vision intact in a dark room. Accuracy at using echolocation improved with more self-generated mouth clicks in these expert echolocators. The researchers also linked neural activity in the brain to the ability of blind individuals to determine object location. This activity, alongside behavioral measures, strengthened across click sequences, leading to more accurate object location. Says Garcia-Lazaro, “Basically, we found that, in some experts, there appears to be a summation, or accumulation, of information in the brain that builds up across clicks about object location.”

According to the researchers, this work shows how the brain uses repeated sound information to create representations of the environment in the absence of vision. Garcia-Lazaro expresses excitement about the next steps stemming from this work, including determining what makes blind people adept at echolocation and training people with and without sight to engage their echolocation ability.