1. information about bodily processes and systems provided by an organism’s receptors to enable it to maintain a physiologically desirable internal environment and make adjustments as necessary.

2. the use of an external monitoring device (e.g., electrocardiograph) to provide an individual with information regarding his or her physiological state. When used to help a person obtain voluntary control over autonomic body functions, such as heart rate or blood pressure, the technique is called biofeedback training. It may be applied therapeutically to treat various conditions, including chronic pain and hypertension. See also neurofeedback.