Definitions

1. The many paths through our mind and body that help us respond to life's important events

Emotional Pathways

Joseph LeDoux has dedicated most of his career to tracing the paths emotions take through our brains. He has concentrated his efforts on studying the paths fear takes through our brains and bodies. The following diagram provides a high-level view of those paths.

There are two basic pathways. The fastest is designed to take immediate defensive action, focusing on bodily responses. This happens unconsciously. The other path is a slower but more thoughtful one through our consciousness that allows us to become aware, feel the emotion, and comprehend its meaning.

Events begin with our senses: sight, hearing, smell, taste, and somatic feedback from throughout our body, including touch. The fast track passes any sense of fear directly to our amygdala for action. The amygdala is “emotions central” within our brain. It is connected through our hypothalamus, pituitary glands, and adrenal cortex directly to our bodies. This initiates immediate physiological actions including freezing; muscular preparation for fleeing, or fighting; the distinctive facial expression of fear; stress hormones are released throughout our body; and the Autonomic Nervous System is energized to activate increased blood pressure, increased heart rate, piloerection (goose bumps), and sweating. If we suddenly see a long thin cylindrical object, this path prepares our bodies to defend against a snake attack even before we become conscious it is a snake.

In parallel, the sensory thalamus passes the sensory information to the sensory cortex for analysis that results in perception. Here the sensed cylindrical object gets perceived as either a harmful snake or a harmless stick and is then represented by the corresponding mental symbol. The transition cortex combines the sensory information with long term memories to form a still more detailed and precise appraisal of what has been encountered. Does this sound and smell more like a stick or a snake? Is a snake or a stick dangerous? Finally, detailed long-term declarative memories from the hippocampus are accessed to aid in the appraisal. What happened the last time I encountered one? If it is a dangerous snake, the body has already prepared for action and the defensive strategy can continue. If it is a stick, you can decide to relax and catch your breath. However, in any case your body has tensed up from the fast-track defensive actions that have already occurred and you also become conscious of feeling fear.

Consciousness is our awareness of what is in working memory—the activated long-term memories, short-term memories, and the associated decision processes. The amygdala alerts the brain as well as the body. It arouses the cortex and focuses the attention of working memory, sharpens the senses, and hastens retrieval of long-term memories relevant to this emotion or context. Working memory assesses all of this and makes us conscious that we feel afraid. Feelings arise when the activity of specialized emotional systems get recognized by our consciousness.

Various types of memories are stored using a variety of different systems within the brain. Long term declarative memory, including the memory of an emotion, is stored in the hippocampus. But emotional memory, the raw recollection that something significant happened before, is stored below the level of consciousness in the amygdala. These are retrieved independently and perceived differently by us.

Quotations

• “Our civilization is still in a middle stage, scarcely beast, in that it is no longer guided by instinct, scarcely human in that it is not yet wholly guided by reason.” ~ Theodore Dreiser

References

The Emotional Brain, by Joseph E. Ledoux

Mapping the Mind, by Rita Carter

Descartes' Error: Emotion, Reason, and the Human Brain, by Antonio Damasio

Emotional Intelligence: Why It Can Matter More Than IQ, by Daniel Goleman