Plasticity

Plasticity is the ability of nervous system to rewire itself. It happens all the time during a person’s life time – during learning as well as after trauma. However, the extent of it varies with age. After injuries or conditions like stroke, the nervous system has the innate ability to regain most of its lost function. However, this recovery is not complete.

At the Brain Repair Centre, we are trying to find ways of understanding as well as enhancing plasticity so as to improve recovery from stroke & trauma. Work is currently being carried out to understand the molecular mechanisms and signalling pathways involved in modulating plasticity in different models. We have now developed sophisticated animal models to study the consequences of brain injury and stroke. The Fawcett group has been working on the role of plasticity in spinal cord injury repair strategies. Their group has shown that removal of Proteoglycans using Chondroitinase enzyme increased the ability of axons to regenerate, mostly due to enhanced plasticity.  They have also shown that removal of perineuronal nets improve plasticity in visual cortex of adult animals.  Currently, work is being focussed on the biochemical mechanisms of perineuronal net formation. Understanding this process will give further insights into regulation of plasticity in brains of animals at different stages of development.  We are also in the process of evaluating the role of physiotherapy in promoting directed plasticity, encouraging nerve fibres to make the right connections.  We have now shown that combining rehabilitation with Chondroitinase treatment after spinal cord injury shows a much larger effect than either of those alone in the ability of the animal to hold its food using paws. 

Image (click for high resolution image): Picture showing the effect of Chondroitinase treatment. Perineuronal nets, which restrict the plasticity in adults, is completely removed after injection of the drug (central part of the section) as compared to those regions of brain where the drug didn’t diffuse (extreme right and left corners of the frame)

Further reading:

Buttery P, Beg AA, Chih B, Broder A, Mason CA, Scheiffele P. The diacylglycerol-binding protein alpha1-chimaerin regulates dendritic morphology (2006) Proc Natl Acad Sci USA 103(6):1924-9.

Gallagher CN, Hutchinson PJ, Pickard JD. Neuroimaging in trauma (2007) Curr Opin Neurol. 20 (4) : 403-9.

Moustafa RR, Baron JC. Imaging in ischaemic stroke – implications for acute management (2007) Crit Care. 2007;11(5):227.

García-Alías G, Lin R, Akrimi SF, Story D, Bradbury EJ, Fawcett JW. Therapeutic time window for the application of chondroitinase ABC after spinal cord injury (2008) Exp Neurol.  210(2):331-8.