Current Projects

Action mapping in people born without hands

Individual differences in brain reorganization following congenital blindness

The neural correlates of sensory restoration

Key Findings

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:

Striem-Amit E., Cohen L., Dehaene S., and Amedi A. (2012). Reading with sounds: Sensory substitution selectively activates the visual word form area in the blind, Neuron
Striem-Amit E. and Amedi A. (2014). Visual cortex extrastriate body-selective area activation in congenitally blind people seeing by using sounds, Current Biology
Heimler B. Striem-Amit E., Amedi A. (2015) Origins of task-specific sensory-independent organization in the visual and auditory brain: neuroscience evidence, open questions and clinical implications, Current Opinion in Neurobiology
Striem-Amit E, Dakwar O, Reich L, Amedi A. (2012) The large-scale organization of "visual" streams emerges without visual experience, Cerebral Cortex

Motorically-Independent Hand and Action Representations

What role do active motor exploration and experience play in guiding brain organization? Does the visual representation of actions in our brain require the ability to perform the same action?

Studying a unique population of people born without hands who use their feet for typically-manual tasks, we found that the activation patterns and connectivity of visual brain regions that conventionally process hands (visual hand-selective areas, action observation network) develop typically. This demonstrates that the computations and wiring of visual brain regions are independent not only from visual experience (as shown above in blindness) but also from motor experience.

In contrast, the primary sensorimotor cortex (S1/M1) showed takeover of the primary hand area by nearby cortical territories (e.g., shoulder), despite compensatory use of their feet to perform manual tasks. This suggests that only association sensorimotor cortex representations are abstract enough to allow for cross-effector plasticity.

Selected publications:

Striem-Amit E., Vannuscorps G., and Caramazza A. (2017). Sensorimotor-independent development of hands and tools selectivity in the visual cortex, Proceedings of the National Academy of Sciences
Vannuscorps G., Wurm, M., Striem-Amit E. and Caramazza A. (2018). Large-scale organization of the hand action observation network in individuals born without hands, Cerebral Cortex
Striem-Amit E., Vannuscorps G., and Caramazza A. (2018). Plasticity based on compensatory effector-use in the association but not primary sensorimotor cortex of people born without hands, Proceedings of the National Academy of Sciences

Large-Scale Brain Connectivity Develops Without Sensory Experience

Do early topographical cortices develop typically in the absence of any sensory experience?

Studying people born blind and deaf, we showed that the large-scale network organization of the early and association visual (V1) and auditory (A1) cortex develop their topographical patterns regardless of visual and auditory experience, respectively. These patterns mimic the retinotopic and tonotopic patterns in control subjects, suggesting full sensory deprivation allows intact sensory network organization even for early topographic cortices. Thus, this organization likely emerges due to prenatal constraints and as it does not degenerate in life-long cross-modal plasticity, it may potentially be capable of supporting late-onset sensory restoration.

Selected publications:

Striem-Amit E., Ovadia-Caro S., Caramazza A., Margulies D., Villringer A. and Amedi A. (2015). Functional connectivity of visual cortex in the blind follows retinotopic organization principles, Brain
Striem-Amit E., Almeida J., Belledonne M., Chen Q., Yuxing Y., Han Z., Caramazza A., Bi Y. (2016). Topographical functional connectivity patterns exist in the congenitally, prelingually deaf, Scientific Reports