Motor imagery of walking following training in locomotor attention. The effect of "the tango lesson".

The hypothesis of this study is that focusing attention on walking motor schemes could modify sensorimotor activation of the brain. Indeed, gait is a learned automated process, mostly regulated by subcortical and spinal structures. We examined the functional changes in the activity of the cerebral areas involved in locomotor imagery tasks, before and after one week of training consisting of physical and mental practice. The aim of the training was to focus the subject's conscious attention on the movements involved in walking. In our training, subjects were asked to perform basic tango steps, which require specific ways of walking; each tango lesson ended with motor imagery training of the performed steps. The results show that training determines an expansion of active bilateral motor areas during locomotor imagery. This finding, together with a reduction of visuospatial activation in the posterior right brain, suggests a decreased role of visual imagery processes in the post-training period in favor of motor-kinesthetic ones.

Developmental and lesion effects in brain activation during sentence comprehension and mental rotation.

The development of neurocognitive networks was examined in 2 cognitive paradigms: auditory sentence comprehension and mental rotation of alphanumeric stimuli. Patterns of brain activation were measured with whole brain echoplanar functional magnetic resonance imaging at 3 Tesla in 5 adults (20-28 years old), 7 children (9-12 years old), and 6 pediatric patients (9-12 years old) with perinatal strokes or periventricular hemorrhages. Healthy children and adults activated similar neurocognitive networks, but there were developmental differences in the distribution of activity across these networks. In the sentence task, children showed more activation in the inferior visual area suggesting an imagery strategy rather than a linguistic strategy for sentence processing. Furthermore, consistent use of a sentence comprehension strategy, whether correct or incorrect as compared to chance performance, was associated with greater activation in the inferior frontal area (Broca's) in both children and pediatric patients. In the mental rotation task, healthy adults showed more activation in the superior parietal and middle frontal areas and less activation in the supramarginal gyrus, suggesting adults were primarily engaged in visual-spatial manipulation and less engaged in the recognition of noncanonical views of stimuli. The pediatric patients showed patterns of activation consistent with organization of cognitive processing into homologous areas of the contralateral hemisphere.