The input currents Isensor, Itarget are fed into an input layer of spiking neurons. The input layer is connected with a central layer of 16 spiking neurons, which are then fully-connected to the motor neuron. The output from the central layer is added with a bias component (denoted in blue in Fig. 1(b)), which generates the standard gait pattern of walking straight forward. This constructs a neural network with spiking neurons (Fig. 1(b)). The synaptic connection weights between the neuron layers determine how the external information adjusts the control signals from the bias neurons and eventually modifies the standard gait pattern.