Neural correlates of training-induced improvements of calculation skills in patients with brain lesions.

Abstract

The loss of calculation skills due to brain lesions leads to a major reduction in the quality of life and is often associated with difficulties of returning to work and a normal life. Very little is known about the neural mechanisms underlying performance improvement due to calculation training during rehabilitation. The current study investigates the neural basis of training-induced changes in patients with acalculia following ischemic stroke or traumatic brain lesions. Functional hemodynamic responses (fMRI) were recorded in seven patients during calculation and perceptual tasks both before and after acalculia training. Despite the heterogeneity of brain lesions associated with acalculia in our patient sample, a common pattern of training-induced changes emerged. Performance improvements were associated with widespread deactivations in the prefrontal cortex. These deactivations were calculation-specific and only observed in patients exhibiting a considerable improvement after training. These findings suggest that the training-induced changes in our patients rely on an increase of frontal processing efficiency.