Article

Subcortical capsular stroke has a poor prognosis, and it is not yet
fully understood how and under what circumstances reach training contributes to
motor recovery. Objective
this study was performed to investigate changes in
neuronal circuits and motor recovery in a chronic capsular stroke model in the
presence or absence of reach training. METHOD:
We generated photothrombotic
capsular lesions in 42 Sprague-Dawley rats and evaluated motor recovery with or
without daily training in a single-pellet reaching task (SPRT).
We used
2-deoxy-2-[18F]-fluoro-D-glucose-microPET (positron emission tomography) to
assess remodeling of neuronal circuits. RESULTS:
SPRT training was selectively
beneficial only for the group with incomplete capsular destruction (P < .05),
suggesting the relevance of plasticity in the remaining capsular fibers for motor
recovery. Groups that did not receive SPRT training showed no motor recovery at
all. The microPET analysis demonstrated that motor recovery was correlated with a
reduction in cortical diaschisis in ipsilesional motor and sensory cortices and
in the contralesional sensory cortex (Pearson's correlation, P < .05). We also
observed training-dependent subcortical activation in the contralesional red
nucleus, the internal capsule, and the ventral hippocampus (P < .0025; false
discovery rate q < 0.05). The groups without reach training did not show the same
degree of reduction in diaschisis or activation of the red nucleus. CONCLUSIONS:
Our results suggest that motor recovery and remodeling of neuronal circuits after
capsular stroke depend on the magnitude of the capsular lesion and on the
presence or absence of reach training. Task-specific training is strongly
indicated only when there is incomplete destruction of the capsular fibers.
CI - (c) The Author(s) 2016.

Langue : ANGLAIS