Anatomy of Emotion

Abstract

Traditionally, we distinguish between the emotional experience and the expression of emotional states. Emotional experience refers to subjective states, the result of conscious introspection. Conversely, the expression of emotional states can be objectively measured and involves behavioral responses and endocrine and autonomic changes. On experimental grounds, the expression of emotional states is usually examined in motivated responses critical to survival, such as ingestive, reproductive, and defensive behaviors. Thus, as expected, much more is known about the neural substrates of emotional expression than about emotional experience. In the present chapter, we took the first step to understand how the nervous system organizes emotional states and provided an overview of the structural organization of the neural circuits involved in such control. We have presented a historical overview of the limbic system concept and separated the limbic system elements to examine their intrinsic organization and connectivity. Here, we discuss the cingulate and orbitofrontal cortices and the functional consequences of cortical limbic lesions; the hippocampal formation circuitry and its role in memory, navigation, and the control of emotional behavior; the amygdala circuitry and its role in the modulation of motivated behaviors; the hypothalamus and the behavior control column critical for the expression of ingestive, reproductive, and defensive behaviors; and the nucleus accumbens as a critical node of the limbic circuit to translate motivation into action.