The article reviews psychophysiological and neuroscience studies on emotional processing conducted by investigators at the University of Florida's Center for the Study of Emotion and Attention (CSEA). The research focuses on reflex reactions, neural structures, and functional circuits that mediate emotional expression, emphasizing the role of motivational circuits in the brain that evolved to ensure survival. These circuits respond to environmental and memory cues, mediating both appetitive and defensive reflexes that tune sensory systems and mobilize the organism for action. The study assesses the reflex physiology of emotion, both autonomic and somatic, using methods such as electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) to explore the brain's motivational circuits that determine human emotion. The authors propose that experienced emotions are founded on the activation of neural circuits that evolved to ensure survival, engaging sensory systems to increase attention and facilitating perceptual processing, while also initiating reflex responses that mobilize the organism and prompt motor action. The research highlights the dual motivational systems: one defensive and associated with unpleasant affect, and one appetitive and associated with pleasant affect. The defense system is a fight-or-flight circuit, while the appetitive system is activated in responses to food, sex, and nurturing. The article also discusses the predator-prey interaction, where responses vary systematically with the imminence of confrontation, and the role of motivational cues in modulating brain potentials and autonomic responses. The late positive potential (LPP) is a reliable index of motivational relevance, varying with the intensity of emotional arousal and the vigor of motivational system activation. fMRI studies show that emotional stimuli elicit enhanced activation in visual processing areas, particularly in the amygdala and inferotemporal cortex, suggesting re-entrant projections from motivational circuits to the sensory system. The article concludes by exploring the differences in brain circuit activation for pleasant and unpleasant cues, showing that while the amygdala is highly responsive to both appetitive and aversive stimuli, specific neural structures like the nucleus accumbens and medial prefrontal cortex are activated only for appetitive cues. Emotional imagery also activates similar neural circuits, with the nucleus accumbens and medial prefrontal cortex being selectively engaged for pleasant scenes.The article reviews psychophysiological and neuroscience studies on emotional processing conducted by investigators at the University of Florida's Center for the Study of Emotion and Attention (CSEA). The research focuses on reflex reactions, neural structures, and functional circuits that mediate emotional expression, emphasizing the role of motivational circuits in the brain that evolved to ensure survival. These circuits respond to environmental and memory cues, mediating both appetitive and defensive reflexes that tune sensory systems and mobilize the organism for action. The study assesses the reflex physiology of emotion, both autonomic and somatic, using methods such as electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) to explore the brain's motivational circuits that determine human emotion. The authors propose that experienced emotions are founded on the activation of neural circuits that evolved to ensure survival, engaging sensory systems to increase attention and facilitating perceptual processing, while also initiating reflex responses that mobilize the organism and prompt motor action. The research highlights the dual motivational systems: one defensive and associated with unpleasant affect, and one appetitive and associated with pleasant affect. The defense system is a fight-or-flight circuit, while the appetitive system is activated in responses to food, sex, and nurturing. The article also discusses the predator-prey interaction, where responses vary systematically with the imminence of confrontation, and the role of motivational cues in modulating brain potentials and autonomic responses. The late positive potential (LPP) is a reliable index of motivational relevance, varying with the intensity of emotional arousal and the vigor of motivational system activation. fMRI studies show that emotional stimuli elicit enhanced activation in visual processing areas, particularly in the amygdala and inferotemporal cortex, suggesting re-entrant projections from motivational circuits to the sensory system. The article concludes by exploring the differences in brain circuit activation for pleasant and unpleasant cues, showing that while the amygdala is highly responsive to both appetitive and aversive stimuli, specific neural structures like the nucleus accumbens and medial prefrontal cortex are activated only for appetitive cues. Emotional imagery also activates similar neural circuits, with the nucleus accumbens and medial prefrontal cortex being selectively engaged for pleasant scenes.