EXG: a simultaneous EMG and EEG recording to study movements from the genesis into the brain to the actuation in the muscle

Moving a muscle implies the communication between the muscle and the brain. The impulse is generated in the motor cortex and it is carried by the nerves to the motor end plate on the muscle where it stimulates the muscle to contract. To study the phenomenon in a fully comprehensive way then is necessary to evaluate an EXG signal composed not only by the myoelectric signal(EMG) but also by the electroencephalographic(EEG) one. For this reason we’ve designed two acquisition devices to analyze simultaneously EMG and EEG signal. The muscle activation is recorded using a multichannel Average Threshold Crossing wireless system, based on Willison principle. The device is composed by a trasmitter and a receiver.The trasmitter comprises a signal amplifier, an asynchronous threshold detector and an asynchronous IR-UWB transmitter. The receiver comprises an asynchronous IR-UWB receiver plus a digital logic which implements a windowing algorithm on the received events. To evaluate brain activity we’ve designed a multi channel EEG acquisition system that removes noise and amplifies the input signal through Butterworth filters. A Right Leg Driver amplifier is employed to improve the common- mode rejection of the device. The eeglab matlab toolbox is used to analyze the raw signal recorded and to draw, using the indipendent components analysis (ICA), a map of the scalp with the different neural activities. The results of the in vivo experiment of the two devices were promising, the signals obtained were good and they reflected correctly brain and muscles activation. The next step will be totally integrate the two devices to obtain an EXG acquisition system. This will made possible to study the movement from the genesis into the brain to the actuation in the muscle.