Growing gray matter

A new study appearing in the medical journal Stroke (a publication of the American Heart Association) looks at the brain's amazing capacity to respond to injury.

Detailed MRI images of stroke patients showed that Constraint Induced (CI) therapy produces a significant increase in the amount of gray matter present in the brains of patients. Constraint-induced movement therapy (CI) forces the use of the affected side by restraining the unaffected side.

This is the first time a rehabilitation therapy has been shown to produce structural changes in the human brain after injury.

What causes the increase in gray matter is still unknown. It may be due to an increase in the amount of blood vessels in the brain, or in the number of synaptic connections between neurons. It may reflect an increase in the amount of glial cells in the brain. Or perhaps most intriguingly, the brain may actually be creating more neurons.

It's only in the past few years that the scientific community has come to accept the idea that the adult brain can continue to generate new neurons through a process called neurogenesis.