Developed in his (1999) book, "The Feeling of What Happens", Antonio Damasio's theory of consciousness proposes that consciousness arises from the interactions between the brain, the body, and the environment. According to this theory, consciousness is not a unitary experience, but rather emerges from the dynamic interplay between different brain regions and their corresponding bodily states. Damasio argues that our conscious experiences are influenced by the emotional responses that are generated by our body's interactions with the environment, and that these emotional responses play a crucial role in shaping our conscious experience. This theory emphasizes the importance of the body and its physiological processes in the emergence of consciousness.
Damasio's three layered theory is based on a hierarchy of stages, with each stage building upon the last. The most basic representation of the organism is referred to as the Protoself, Core Consciousness, and Extended Consciousness. Damasio's approach to explaining the development of consciousness relies on three notions: emotion, feeling, and feeling a feeling. Emotions are a collection of unconscious neural responses that give rise to feelings. Emotions are complex reactions to stimuli that cause observable external changes in the organism. A feeling arises when the organism becomes aware of the changes it is experiencing as a result of external or internal stimuli.
Protoself
According to Damasio's theory of consciousness, the protoself is the first stage in the hierarchical process of consciousness generation. Shared by many species, the protoself is the most basic representation of the organism, and it arises from the brain's constant interaction with the body. The protoself is an unconscious process that creates a "map" of the body's physiological state, which is then used by the brain to generate conscious experience. This "map" is constantly updated as the brain receives new stimuli from the body, and it forms the foundation for the development of more complex forms of consciousness.
Damasio asserts that the protoself is signified by a collection of neural patterns that are representative of the body's internal state. The function of this 'self' is to constantly detect and record, moment by moment, the internal physical changes that affect the homeostasis of the organism. Protoself does not represent a traditional sense of self; rather, it is a pre-conscious state, which provides a reference for the core self and autobiographical self to build from. As Damasio puts it, "Protoself is a coherent collection of neural patterns, which map moment-by-moment the state of the physical structure of the organism" (Damasio 1999).
Multiple brain areas are required for the protoself to function. Namely, the hypothalamus, which controls the general homeostasis of the organism, the brain stem, whose nuclei map body signals, and the insular cortex, whose function is linked to emotion. These brain areas work together to keep up with the constant process of collecting neural patterns to map the current status of the body's responses to environmental changes. The protoself does not require language in order to function; moreover, it is a direct report of one's experience. In this state, emotion begins to manifest itself as second-order neural patterns located in subcortical areas of the brain. Emotion acts as a neural object, from which a physical reaction can be drawn. This reaction causes the organism to become aware of the changes that are affecting it. From this realization, springs Damasio's notion of “feeling”. This occurs when the patterns contributing to emotion manifest as mental images, or brain movies. When the body is modified by these neural objects, the second layer of self emerges. This is known as core consciousness.