Functional recovery after brain lesion???contralateral neuromodulation: an fMRI study

Abstract

Behavioral recovery takes place even after permanent damage to the entire brain region normally controlling sensorimotor hind limb function in the rat. In our study, 2 weeks after full behavioral recovery from an experimental unilateral permanent brain damage, the topographic representation of the previous paretic hindlimb was investigated by fMRI. The analysis showed that during electrical stimulation of the previously paretic hindlimb, two normally inactive brain regions were now being activated. One region was the non-damaged contralateral sensori-motor cortex and the other region was located lateral to the lesion. These results suggest that behavioral recovery can be explained by functional reorganization and neuromodulation of the brain.

In Vivo Calcium Imaging Reveals Functional Rewiring of Single Somatosensory Neurons after Stroke

“…Comparison with previous studies of plasticity after stroke In patients (Rossini et al, 2007) and animal stroke models (Abo et al, 2001;Dijkhuizen et al, 2001Dijkhuizen et al, , 2003Wei et al, 2001;Zepeda et al, 2003Zepeda et al, , 2004, ipsilesional regional reorganization as observed here is correlated with improved behavioral recovery. In rats with small infarcts, activity within the stroke-affected cortex was required for reaching task performance (Biernaskie et al, 2005).…”

PET Imaging of Serotoninergic Neurotransmission with [11C]DASB and [18F]altanserin after Focal Cerebral Ischemia in Rats

“…4 The functional recovery includes some mechanisms, such as neo-formation of brain vessel, increase in axonal sprouting, development of new dendrites, and functional reorganization through recruitment of new brain regions, and neuromodulation to the opposite hemisphere. 5 Recently, brain function restoration after brain damage has also been related to changes in the dopaminergic neurotransmission system after cerebral ischemia in rats. 6 Likewise, clinical studies have shown that the use of pharmacological therapies that increase brain concentrations of brain amines such as dopamine and serotonin promotes a positive impact on stroke outcomes.…”

In vitro studies on ultrasmall superparamagnetic iron oxide nanoparticles coated with gummic acid for T2 MRI contrast agent

“…2 The prepared suspensions of coated magnetic nanoparticles have recently been the focus of intensive research not only for the study of the physics of magnetism in the nanometer scale, 3 but also for the use of ferrofluids in many technological and biomedical applications such as technical heating processes, media contrast agents in magnetic resonance imaging ͑MRI͒, and as therapeutic agents for RF-magnetic hyperthermia. [4][5][6][7][8][9][10][11][12][13] Specifically, MRI contrast agents are chemical substances introduced to the anatomical or functional region being imaged, in order to increase the differences between different tissues or between normal and abnormal tissue, by altering the relaxation times. MRI contrast agents are classified according to the different changes in relaxation times after their injection.…”