Lower limb muscle activity during neurointerface control: neurointerface based on motor imagery of feet dorsiflexion
Abstract
Neurorehabilitation of motor functions using a neurointerface (BCI) with feedback is a modern promising area of research. However, there is very little data on muscle activity during the motor imagery of lower limb – an important aspect of rehabilitation. The EMG activity of the lower limb muscles was studied in 42 healthy participants which control BCI, based on kinesthetic motor imagery of dorsiflexion of the feet and supplemented by a robotic device for moving the limbs “Biokin” (mechanotherapy), activated in case of successful motor imagery. It is shown that BCI control leads to an increase in the activity (averaged all over the participants) of the muscle, whose movement provides an imaginary movement in reality – the tibialis anterior (TA). In addition, the activity of the gastrocnemius muscle – the antagonist of TA – increases, which is apparently associated with the instruction to imagine, but not to make a movement. Activation of the mechanical training device (AM) additionally increases TA EMG (up to 100-200%) and weakly but significantly (by 3–5%) reduces the activity of the thigh muscles (quadriceps and left biceps). Therefore, AM increases the targeting of the downward signal that occurs during the motor imagery. Muscle reactions to the motor imagery are individual. Thus, the use of BCI based on the motor imagery of dorsiflexion of the feet and the use of the mechanical training device, which ensures the closure of the feedback loop when imagining this movement, contributes to the targeted activation of TA – the muscle that provides dorsiflexion of the foot, which is important for the clinical rehabilitation of paretic foot movements.