The brain has two main pathways that can lead to the generation of anxiety. These pathways, although distinct, can also work together.
- The cortex pathway begins with the sense organs and travels through the thalamus to the cerebral cortex, the thinking part of the brain. The frontal lobes within the cortex play a significant role by anticipating and interpreting situations, which can lead to worry and anxiety even when no immediate danger is present. Thoughts and images generated in the cortex (left hemisphere for thoughts, right hemisphere for images) can then send signals that activate the amygdala, leading to an anxiety response. This pathway is more conscious, and we are often aware of the thoughts and interpretations involved.
- The amygdala pathway is a more direct and rapid route. Sensory information travels from the thalamus directly to the amygdala, which is a primitive part of the brain involved in processing emotions like fear and anxiety. The lateral nucleus of the amygdala receives this sensory input and, based on past emotional memories (often formed through association), can quickly trigger the fight-or-flight response and its associated physical symptoms even before the cortex has fully processed the information. This pathway operates quickly and often without conscious awareness of the trigger. The amygdala is considered central to triggering the anxiety response, even when initiated by the cortex.