Objective: The aim of the study was to investigate the role of the motor cortex in the initiation and end phase of locomotion and the influence of slope during walking.
Method: Ten Sprague-Dawley rats were enrolled in the experiment. In five rats a micro-wire 16 channel electrode array was chronically implanted in the primary motor cortex (M1) and a 4 channel intramuscular fine wire EMG electrode (bipolar) was implanted in the muscles vastus lateralis (VL) and biceps femoris (BF) of the right hindlimb. Over five days, intra-cortical signals (IC) and EMG data were recorded simultaneously with high-speed videography while the rat performed locomotion on a horizontal and inclined treadmill.
Results: The mean motor cortical cell discharge from one channel for all locomotor tasks showed similar shape demonstrating continuity between the curves for two rats. No increase was found in the firing rate between
the different locomotor tasks. The EMG amplitude increased significantly in BF muscle during the inclined task compared to horizontal locomotion.
Conclusion: In conclusion, our study suggests that the M1 does not play a major role in the initiation and end phase of locomotion and during inclined locomotion. However, the applied protocol allows a temporal correlation of IC signals, EMG and kinematic parameters that can be used to investigate neuronal activity in relation to muscle activity during gait.