The name of the specific Electronic Instument used to monitor physiological changes mostly regulated by the autonomic nervous? Please do not answer Bio-feedback. that is the result of utilizing the Electronic Instrument. Not the instument itself.

Biofeedback is the process of gaining greater awareness of many physiological functions of one's own body, commercially by using electronic or other instruments, and with a goal of being able to manipulate the body's systems at will. Humans conduct biofeedback naturally all the time, at varied levels of consciousness and intentionality. Biofeedback and the biofeedback loop can also be thought of as self-regulation.[1][2] Some of the processes that can be controlled include brainwaves, muscle tone, skin conductance, heart rate and pain perceptions