Key Findings

Brain Plasticity Differs Between Individuals with Blindness or Deafness

Does brain reorganization take the same form across individuals with blindness or deafness?

We studied people born with blindness and found that their primary visual cortex connected to other brain areas in different ways from person to person—but each person’s pattern stayed stable over time. We saw a similar pattern of individual variability in people born with deafness. 

This suggests that brain plasticity is unique to each person, likely shaped by both biology and experience. These differences may help explain why people respond differently to rehabilitation and allow for more personalized approaches. 

Selected publications: 

Brain Representations of Action Do Not Depend on Having Hands

What role does motor experience play in guiding brain organization? And does the brain need hands to develop normal representations of hand actions? 

We studied people born without hands who use their feet to perform everyday tasks like reaching, grasping, and using tools. Their brains showed the same activity patterns as people with hands doing the same actions—whether using their hands or feet. This shows that some parts of the brain focus on what action is being done, not how or with which body part. This means that parts of the motor circuit codes for actions more abstractly, in a way that generalizes across body parts, and may support coding for the same actions even if one loses a limb. This abstract code may potentially also be mined for controlling arm prostheses.

Selected publications: 

Plasticity Types Vary Along a Motor Hierarchy

Can all brain regions meaningfully adapt to developing without hands? Or are some areas fixed in their roles? 

While higher-level motor brain areas flexibly represent actions regardless of the body part used (see above), lower-level areas show more rigid organization. The part of the brain that directly controls movement and touch (the primary sensorimotor cortex) did not show this flexibility. Instead of being taken over by the foot, the area normally used for the hand was taken over by nearby body parts, like the shoulder—even though these individuals use their feet for hand-like tasks. This suggests that higher-level motor areas are more flexible, while lower-level areas are more limited and follow a fixed body-based layout. It shows that the brain's ability to reorganize depends on the role of each region. 

Selected publications: 

Large-Scale Brain Connectivity Develops Without Sensory Experience

Can early topographic brain areas organize normally without any sensory input?

By studying people born blind or deaf, we found that key visual and auditory brain regions still develop normal large-scale organization, even without ever receiving sight or sound. These topographic brain connectivity patterns (retinotopic or tonotopic, respectively) looked similar to those in people with typical vision and hearing, suggesting this connectivity layout forms before birth. Since these remain stable even with lifelong sensory loss, this organization may help support future sensory restoration.

Selected publications: 

The Visually-Independent Organization of The Association Visual Cortex

Does visual cortex organization and function depend on vision? 

We conducted a series of neuroimaging experiments using sensory substitution, which translates the visual input stream to sounds. Following training, people born blind were able to perceive and identify complex visual information presented through sounds (e.g., facial expressions). We showed that they process this sensorially-transformed information in the typical visual cortex areas specializing in processing analogous visual information across multiple visual information types and tasks. These studies suggest that the association visual cortex of the blind is organized for processing information from specific content domains and tasks—regardless of the input sensory modality—and does not require visual experience during critical periods of development.

Selected publications: