Somatosensory Feedback for Brain-Machine Interfaces: Perceptual Model and Experiments in Rat Whisker Somatosensory Cortex

A model that predicts psychophysical ability to discriminate electrical stimulation trains is presented. Our model is a leaky integrator, which operates based on the hypothesis that the perceived intensity of a stimulus train is a function of the total number of action potentials evoked over the volume of stimulated neurons. The model predictions are validated with our experimental results obtained from four Long Evans rats on a two-alternative behavioral task. The rats were stimulated in the whisker barrel cortex using frequency, amplitude, and duration modulation. Our results demonstrate that the rats generalized the perception of frequency, amplitude, and duration of stimulation, in a manner consistent with the model. The surprising finding of our work is that the model is able to accurately predict the psychophysical discrimination of intensity, without accounting for the neural network properties of the somatosensory cortex.