Fear, anxiety, and worry are complex emotional states that involve various processes in the brain and are crucial for survival. Let’s review how they are processed in the brain. Then, we will discuss how exposure therapies can help with fear, anxiety, and worrying.

FEAR

Fear is a response to imminent threat. It most often begins with a sensory stimulus, which could be a sight, sound, or other cue that signals potential danger. After the sight, sound, or other cue is processed by the sensory organs (e.g., eyes, ears), the signal is sent to a relay station in the brain called the thalamus, which then sends the signal to the amygdala.

The amygdala is a structure deep within the brain that assesses the emotional relevance of sensory stimuli. If the amygdala perceives the stimulus as a threat, it quickly activates a response by sending signals that initiate the body's fight-or-flight (or freeze) response (i.e., elevated heart rate, respiratory rate, sweating, vision changes).

Simultaneously, the thalamus also sends sensory signals to the brain’s cerebral cortex, the area responsible for higher-order thinking and evaluation. The cortex decides whether the perceived threat is real and modulates the amygdala's response accordingly (i.e., shuts it down/off).

The hippocampus, which is crucial for memory, is also activated which helps us remember the experience for the future. Unfortunately, as you will see, this also means the fear circuit can be triggered by experiences that remind you of the past threatening experience.

ANXIETY AND WORRYING

Unlike fear, which is a response to a specific and present threat, anxiety and worrying involve the anticipation of future threats. Anxiety is more a feeling/emotion whereas worry is more a cognitive process characterized by repetitive, uncontrollable thoughts about potential negative future events.

The amygdala, as described above, also plays a role in both anxiety and worrying. People with anxiety often have an overly sensitive amygdala which means they are more likely to perceive neutral or uncertain situations as threatening.

The cerebral cortex, which is involved in planning, decision-making, foresight, and attention, has direct connections with the amygdala and assesses and sometimes overestimates the danger or negative outcomes of future events. This is because the cerebral cortex may be unable to shut down the heightened responses from the amygdala, which leads to chronic anxiety and worrying.

Finally, the hippocampus is responsible for storing emotional memories for the future. Unfortunately, this means the neural circuits for fear, anxiety, and worry can be triggered by experiences that remind you of the past threatening experience.

NEUROTRANSMITTERS (BRAIN CHEMICALS)

Neurotransmitters (brain chemicals) like serotonin, norepinephrine, and gamma-aminobutyric acid (GABA) are important in regulating the circuits described above. These brain chemicals alter the activity of the circuits and can increase or decrease anxiety and worrying. This is why medications that alter serotonin (e.g., Prozac, Zoloft, Lexapro), Norepinephrine (e.g., Cymbalta, Effexor, Prazosin), and GABA (Xanax, Valium, Ativan, Klonopin) signaling are helpful for people with anxiety.

SUMMARY OF FEAR, ANXIETY, AND WORRY IN THE BRAIN

Thalamus: A relay station in the brain for sensory and motor signals.

Amygdala: This is the brain's fear center. It's responsible for detecting threats and initiating the body's fight-or-flight response. In people with anxiety disorders, the amygdala may be hyperactive or overly sensitive.

Cerebral Cortex: These regions have direct connections with the amygdala and are important in regulating emotions and exerting control over the amygdala's fear responses. The cerebral cortex is involved in higher-order functions like attention, planning, decision-making, and moderating social behavior. It's also crucial for regulating emotions and exerting control over the amygdala's fear responses.

Hippocampus: This area plays a key role in forming and retrieving memories, including those that elicit fear or anxiety.

VIDEO: Neurobiology of Anxiety and Worry

___ This post was reviewed by a licensed medical professional.