Reproducible Quantitative Stimulation Allows New Analysis of Crayfish Muscle Receptor Organ Responses

The crustacean muscle receptor organ (MRO) has provided a particularly accessible preparation for the study of sensory coding, which has been widely used in introductory laboratory courses incorporating extracellular recording from sensory nerves in living preparations. We describe three innovations to the standard laboratory exercise using the MRO: (1) a new form of suction electrode to facilitate extracellular recording; (2) a new, Arduino-driven actuator to allow reproducible and quantifiable mechanical stimulation of the MRO; and (3) a new approach to the crayfish abdomen preparation that allows linear extension of the MRO muscles. These novel approaches allow the collection of data sets comprised of sensory cell spike trains under software control as important mechanical stimulus parameters are varied systematically through software. This additional level of user control facilitates a more robust quantitative approach to the analysis of MRO sensory neuron spike trains, which is facilitated by training in data analysis using python.