Behavioral and neuroplastic changes in the blind: evidence for functionally relevant cross-modal interactions.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing behavioral, neuroimaging, and TMS findings in blind and sighted subjects
PubMed 15477034 · doi:10.1016/j.jphysparis.2004.03.009
What was done
The authors reviewed literature examining neuroplastic reorganization and behavioral adaptations following visual deprivation in blind individuals as well as experimental observations in temporarily blindfolded sighted subjects.
What was found
Visual cortical areas are recruited by tactile and auditory modalities to process sensory inputs. Blind Braille readers exhibit an expanded sensorimotor cortical representation for the reading finger. Transcranial magnetic stimulation (TMS)-induced phosphenes were elicited in only 20% of blind subjects. Rapid cross-modal changes observed in blindfolded sighted controls suggest this reorganization is driven by unmasking and potentiating preexisting latent multisensory pathways rather than forming novel structural connections.
Why it matters
Demonstrating that sensory deprivation recruits visual cortex via latent pathways informs the understanding of adult brain plasticity and highlights potential challenges for sensory restoration using visual prostheses.
Limits
The abstract describes a narrative review without detailing search criteria, sample sizes, or quantitative outcome measures beyond the single 20% phosphene elicitation rate. Causality and underlying neural mechanisms remain incompletely characterized.
Cited by
- context Tightly blindfolding normally sighted individuals for 60 minutes is sufficient for their visual cortex to begin responding to sound and touch stimuli.