Corticospinal axons originating from the contralesional cortex have been found to suffer lesion-induced sprouting and cross the spinal cord midline, innervating the deafferented side contralateral to the lesion (Benowitz and Carmichael, 2010 and Liu et al., 2011). Moreover, inhibition of neuronal activity of contralesional sensorimotor cortex leads to impairment of recovered reach-to-grasp movement (Biernaskie et al., 2005). Recruitment of other motor regions, such as red nucleus, might also be involved (Jarratt and Hyland, 1999 and Morris et al., 2011).

Liu et al. (2011) have found significant recovery of success rate induced by treatment with MSCs after middle cerebral artery occlusion (MCAo) in mice. This observation is not in agreement to the present results, but the several differences in experimental approaches should explain Akt inhibitor this discrepancy, i.e., regions affected by Linsitinib solubility dmso ischemia, protocol of pre- and post-ischemic accompaniment, cell type and animal species used. Some hypotheses might explain the absence of significant recovery promoted by BMMCs. First, opposite to MSCs, BMMCs might not be able to promote enough neuroprotection in cortical tissue to permit cortical recruitment for compensatory recovery of reach-to-grasp movement. We observed no effect of BMMCs treatment in the extension of ischemic lesion. This quantitative analysis confirms gross analysis made in a previous study (Giraldi-Guimarães

et al., 2009). However, a significant decrease of neurodegeneration has been observed after the same protocol of treatment (Giraldi-Guimarães et al., FER 2009). Since we have observed recovery of unsophisticated sensorimotor functions (Giraldi-Guimarães et al., 2009, present study), the results suggest that the rescue of a small number of neurons can be sufficient to promote some functional recovery, although it should be unable to result in macroscopic reduction of damage and increase recovery of skilled movements. Nonetheless, every effort should be made to save neurons, even though

a small number. Second, complete recovery of sophisticated movements would not be able to occur after large sensorimotor cortical lesions, except for therapies that might promote reconstruction of lost cortical tissue, e.g., the use of embryonic or induced pluripotent stem cells (Polentes et al., 2012). As discussed above, complete recovery of success rate in reach-to-grasp task has been only found after small focal lesion of motor cortex (Alaverdashvili and Whishaw, 2008). Thus, the present study opens the question about BMMCs capability to recovery skilled movements. To evaluate the deepness of sensorimotor recovery promoted by BMMCs and other cell therapies, time window of cell administration after lesion induction, cell dose, location and extension of brain lesion are some of the experimental approaches that need to be tested in further studies.