Corticospinal inhibition of transmission in propriospinal-like neurones during human walking.

摘要: It is crucial for human walking that muscles acting at different joints are optimally coordinated in relation to each other. This ensured by interaction between spinal neuronal networks, sensory feedback and supraspinal control. Here we investigated the cortical control of excitation from ankle dorsiflexor afferents quadriceps motoneurones mediated propriospinal-like interneurones. During tonic contraction dorsiflexors knee extensors while standing [at matched electromyography (EMG) levels], effect common peroneal nerve (CPN) stimulation on was tested assessing averaged rectified EMG activity, H-reflexes [evoked femoral (FN) stimulation] motor evoked potentials (MEPs) produced transcranial magnetic (TMS). The biphasic facilitation (CPQ-reflex) isolated CPN enhanced during walking, when combined with FN or TMS, resulting MEPs were inhibited. CPQ-reflex also depressed subthreshold TMS. peripheral (in FN) corticospinal volleys may activate inhibitory non-reciprocal group I interneurones, masking excitations proposed cannot be fully explained an increase inputs, but more likely caused central interneurones other sources. importance reducing reflex activity not functionally relevant.