Abstract: A method of detecting a relatively weak signal includes providing an oscillatory loop that can sustain oscillations, wherein the oscillatory loop has no more than one or an even-number of stages. The loop includes a first weakly bistable differential amplifier and a second weakly bistable differential amplifier. At least one of the first and second weakly bistable differential amplifiers is connected to a behavior perturbing coupling which is operative to introduce into the connected-to amplifier a behavior tipping signal where, even if the behavior tipping signal is much weaker than an oscillation of the one or multistage oscillatory loop, the relatively weak behavior tipping signal can nonetheless alter the oscillatory behavior of the multistage oscillatory loop in a distinguishable way. The system may be used for detecting outside a patient's body weak manifestations of internal nerve firings.

Abstract: A method of detecting changes in biologically sourced electrical signals is disclosed. Biologically sourced electrical signals are coupled to a meta-stable and hair-trigger wise perturbable system. The system operates in a first oscillatory mode when the received signals have a strength below a first predetermined level and operates in a distinguishable second oscillatory mode when the received signals have strengths above the first predetermined level but below a second predetermined level. The strengths of the received and thusly distinguishable signals may be in a range below 10 picoAmperes. The biologically sourced electrical signals may be driven by intracranial nerve firings.

Abstract: A method of detecting a relatively weak signal includes providing an oscillatory loop that can sustain oscillations, wherein the oscillatory loop has no more than one or an even-number of stages. The loop includes a first weakly bistable differential amplifier and a second weakly bistable differential amplifier. At least one of the first and second weakly bistable differential amplifiers is connected to a behavior perturbing coupling which is operative to introduce into the connected-to amplifier a behavior tipping signal where, even if the behavior tipping signal is much weaker than an oscillation of the one or multistage oscillatory loop, the relatively weak behavior tipping signal can nonetheless alter the oscillatory behavior of the multistage oscillatory loop in a distinguishable way. The system may be used for detecting outside a patient's body weak manifestations of internal nerve firings.

Abstract: A method of detecting changes in biologically sourced electrical signals is disclosed. Biologically sourced electrical signals are coupled to a meta-stable and hair-trigger wise perturbable system. The system operates in a first oscillatory mode when the received signals have a strength below a first predetermined level and operates in a distinguishable second oscillatory mode when the received signals have strengths above the first predetermined level but below a second predetermined level. The strengths of the received and thusly distinguishable signals may be in a range below 10 picoAmperes. The biologically sourced electrical signals may be driven by intracranial nerve firings.