While experimental studies in the monkey have shown that motor recovery after partial destruction of the hand motor cortex was based on adjacent motor reorgan ization, functional MRI (fMRI) studies with isolated prima...While experimental studies in the monkey have shown that motor recovery after partial destruction of the hand motor cortex was based on adjacent motor reorgan ization, functional MRI (fMRI) studies with isolated primary motor cortical stro ke have not yet been reported in I humans. Based on experimental data, we design ed a study to test if recovery after stroke within primary motor cortex (M1) was associated with reo rganization within the surrounding motor cortex, i.e. the motor cortex was able to vicariate. Since motor recovery is time-dependent and might be inflected acc ording to the tested task, the delay after stroke and two motor tasks were inclu ded in our design. We examined four patients with one ischaemic stroke limited t o M1, and four sex-and age-matched healthy controls in a temporally balanced p rospective longitudinal fMRI study over three sessions:< 20 days, 4 months and 2 years after stroke. The paradigm included two motor tasks, finger tapping (FT) -and finger extension (FE). Distinct patterns of motor activation were observed with time for FT and FE. At the first session, FT-related activation was later alized in the ipsilateral hemisphere while FE-related activation was contralate ral, involving bilateral cerebellar regions for both tasks. From 4 months, skill ed motor recovery was associated with contralateral dorsal promoter and sensorim otor cortex and ipsilateral cerebellum motor-related activations, leading to la teralized motor patterns for both tasks. For the left recovered hand, FT and FE -related activations within M1 were more dorsal in patients than in controls. T his dorsal shift progressively increased over 2 years, rejecting functional reor ganization in the motor cortex adjacent to the lesion. In addition, patients sho wed a reverse representation of FT and FE within M1, corresponding to a greater dorsal shift for FT than for FE. TMs functional dissociation might reflect the s tructural subdivision of M1 with two distinct finger motor representations withi n M1. Recovery of FT展开更多
文摘While experimental studies in the monkey have shown that motor recovery after partial destruction of the hand motor cortex was based on adjacent motor reorgan ization, functional MRI (fMRI) studies with isolated primary motor cortical stro ke have not yet been reported in I humans. Based on experimental data, we design ed a study to test if recovery after stroke within primary motor cortex (M1) was associated with reo rganization within the surrounding motor cortex, i.e. the motor cortex was able to vicariate. Since motor recovery is time-dependent and might be inflected acc ording to the tested task, the delay after stroke and two motor tasks were inclu ded in our design. We examined four patients with one ischaemic stroke limited t o M1, and four sex-and age-matched healthy controls in a temporally balanced p rospective longitudinal fMRI study over three sessions:< 20 days, 4 months and 2 years after stroke. The paradigm included two motor tasks, finger tapping (FT) -and finger extension (FE). Distinct patterns of motor activation were observed with time for FT and FE. At the first session, FT-related activation was later alized in the ipsilateral hemisphere while FE-related activation was contralate ral, involving bilateral cerebellar regions for both tasks. From 4 months, skill ed motor recovery was associated with contralateral dorsal promoter and sensorim otor cortex and ipsilateral cerebellum motor-related activations, leading to la teralized motor patterns for both tasks. For the left recovered hand, FT and FE -related activations within M1 were more dorsal in patients than in controls. T his dorsal shift progressively increased over 2 years, rejecting functional reor ganization in the motor cortex adjacent to the lesion. In addition, patients sho wed a reverse representation of FT and FE within M1, corresponding to a greater dorsal shift for FT than for FE. TMs functional dissociation might reflect the s tructural subdivision of M1 with two distinct finger motor representations withi n M1. Recovery of FT
