Real-time control of stepper motors for mechano-sensory stimulation

Mechanical stimulation is widely used to study sensory encoding in the nervous system of living organisms. The stimulation of mechano-receptor neurons is achieved through a large variety of devices that generate movement or vibration. In many situations, a hard real-time (RT) control of the device (in the millisecond time scale) is needed to produce realistic mechanical stimuli. The real-time control can be required to achieve the desired precision in the device or to implement activity-dependent stimulation protocols that imply the detection of physiological events to drive the stimulus in real time. In this paper we show that real-time software technology can be used to control stepper motors for mechano-receptor stimulation, and to implement artificial closed-loops to address the sensory-motor transformation. We illustrate this using as an example the control of a stepper motor to precisely move gravimetric organs in in vitro preparations.