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.
Ultrasensitive and compact device for noninvasive acquisition of low strength bio signals and method of using same