emotion, andintentional behavior.A primary proposition explored in this article is that different emotions are associated withdistinct patterns of physiological activity. This is the result of a two-way process by which, inone direction, emotions trigger changes in the autonomic nervous system and hormonal system,and in the other direction, specific changes in the physiological substratum are involved in thegeneration of emotional experience. Research at the Institute of HeartMath has identified sixdistinct patterns of physiological activity generated during different emotional states. We callthese psychophysiological modes. Each of these is described in detail in Appendix A. Ofparticular significance is the psychophysiological coherence mode, which is characterized byordered, harmonious patterns of physiological activity. This mode has been found to begenerated during the experience of sustained positive emotions. The psychophysiologicalcoherence mode has numerous physiological and psychological benefits, which can profoundlyimpact health, performance, and quality of life.A second proposition is that the heart plays a central role in the generation and transmissionof system-wide information essential to the bodys function as a coherent whole. There aremultiple lines of evidence to support this proposition: The heart is the most consistent anddynamic generator of rhythmic information patterns in the body; its intrinsic nervous system is asophisticated information encoding and processing center that operates independently of thebrain; the heart functions in multiple body systems and is thus uniquely positioned to integrateand communicate information across systems and throughout the body; and, of all the bodilyorgans, the heart possesses by far the most extensive communication network with the brain. Asdescribed subsequently, afferent input from the heart not only affects the homeostatic regulatorycenters in the brain, but also influences the activity of higher brain centers involved inperceptual, cognitive, and emotional processing, thus in turn affecting many and diverse aspectsof our experience and behavior. These are the central ideas that guide what follows.The Psychophysiological Network: A Systems PerspectiveAs science has increasingly adopted a systems perspective in investigation and analysis, theunderstanding has emerged that our mental and emotional functions stem from the activity ofsystemsorganized pathways interconnecting different organs and areas of the brain and bodyjust as do any of our physiological functions. Moreover, our mental and emotional systemscannot be considered in isolation from our physiology. Instead, they must be viewed as anintegral part of the dynamic, communicative network of interacting functions that comprise thehuman organism.These understandings have led to the emergence and growth of new scientific fields of study,such as psychophysiology. Psychophysiology is concerned with the interrelations among thephysiological, cognitive, and emotional systems and human behavior. It is now evident thatevery thought, attitude, and emotion has a physiological consequence, and that patterns ofphysiological activity continually influence our emotional experience, thought processes, andbehavior. As we will see shortly, the efficacy of this perspective has been substantiated by ourINTEGRAL REVIEWDecember 2009Vol. 5, No. 2own research, as well as that of many others, examining how patterns of psychophysiologicalactivity change during stress and different emotional states.Heart Rate Variability and Measurement of Psychophysiological ModesIn the early stages of our work at the Institute of HeartMath, we sought to determine whichphysiological variables were most sensitive to and correlated with changes in emotional states. Inanalyzing