Optogenetic-guided cortical plasticity after nerve injury.

Mark McIntosh,'s picture
PubMed URL: 
Pelled G
Author List: 
Li N
Downey JE
Bar-Shir A
Gilad AA
Walczak P
Kim H
Joel SE
Pekar JJ
Thakor NV
Pelled G
Proc Natl Acad Sci U S A
PubMed ID: 
Peripheral nerve injury causes sensory dysfunctions that are thought to be attributable to changes in neuronal activity occurring in somatosensory cortices both contralateral and ipsilateral to the injury. Recent studies suggest that distorted functional response observed in deprived primary somatosensory cortex (S1) may be the result of an increase in inhibitory interneuron activity and is mediated by the transcallosal pathway. The goal of this study was to develop a strategy to manipulate and control the transcallosal activity to facilitate appropriate plasticity by guiding the cortical reorganization in a rat model of sensory deprivation. Since transcallosal fibers originate mainly from excitatory pyramidal neurons somata situated in laminae III and V, the excitatory neurons in rat S1 were engineered to express halorhodopsin, a light-sensitive chloride pump that triggers neuronal hyperpolarization. Results from electrophysiology, optical imaging, and functional MRI measurements are concordant with that within the deprived S1, activity in response to intact forepaw electrical stimulation was significantly increased by concurrent illumination of halorhodopsin over the healthy S1. Optogenetic manipulations effectively decreased the adverse inhibition of deprived cortex and revealed the major contribution of the transcallosal projections, showing interhemispheric neuroplasticity and thus, setting a foundation to develop improved rehabilitation strategies to restore cortical functions.
Published Date: 
May, 2011

Kennedy Krieger Institute Announces Retirement of President and CEO

Dr. Gary W. GoldsteinThe Institute’s board of directors is conducting a national search and is expected to name a new CEO in the coming months.
Learn more.

Appointments & Referrals



Read inspiring stories, news and updates about the Institute's patient care, research, special education, professional training, and community programs.


Resource Finder


A free resource that provides access to information and support for individuals and families living with developmental disabilities.