A configurable system is used to evaluate stimulus sensitivity of a subject. An action channel provides a stimulus to the subject and a reaction channel receives a response from the subject. A signal pathway is connected to the action channel and to the reaction channel. A controller establishes loops within the signal pathway. Loop types include a transduction loop including the action channel and forming a path terminating in the signal pathway, and a channel loop including the action channel and terminating at a reference unit. Other possible loop types include an interface loop including the action channel, the reaction channel and the reference unit having an initial parameter value, and an adaptive loop including the action channel, the reaction channel and the reference unit whose parameter value is adapted based on the response from the subject. A method using the system is also described.
