Essentials: Erasing Fears & Traumas Using Modern Neuroscience

Andrew Huberman frames this discussion around the neuroscience of fear, trauma, and post-traumatic stress disorder. He argues that advances in understanding fear circuits have helped explain both how frightening experiences become persistent memories and how treatment might change them. His central proposition is that reducing an established fear response is only part of the process: the old experience must also acquire a new, positive association.

He distinguishes fear from several overlapping experiences. Stress is a physiological response that can occur without fear, although fear incorporates several, if not all, elements of stress. Anxiety often involves stress about a future event, though he acknowledges other meanings; it, too, can occur without fear. Fear combines bodily changes—such as a faster heartbeat and altered skin temperature—with thoughts and memories. His operational description of trauma is a fear response that becomes embedded and reactivates when it is maladaptive. These distinctions establish the biological and cognitive processes he wants to examine rather than a set of diagnostic criteria.

Huberman begins with autonomic arousal. In his account, the sympathetic branch of the autonomic nervous system increases alertness, while the parasympathetic branch supports calming. He describes their relationship as a seesaw that adjusts overall arousal. This provides a vocabulary for separating the physical intensity of a fear response from the particular memory or interpretation attached to it.

He then introduces the hypothalamic-pituitary-adrenal, or HPA, axis. The hypothalamus lies deep at the base of the brain and participates in regulating temperature, sexual behavior, eating, and drinking, including mechanisms that promote and restrain those behaviors. It connects to the pituitary, which releases hormones into the bloodstream. The adrenal glands sit above the kidneys. Huberman highlights adrenaline, also called epinephrine, and cortisol as important chemicals in this discussion, while emphasizing that these so-called stress hormones also participate in ordinary waking from sleep.

The key feature of this system is its timescale. Huberman describes both rapid chemical effects that prepare the body for action and longer-lasting effects that prolong alertness after an event has ended. In his explanation, longer-lasting signaling can feed back to the brain, influence gene expression over many days, and contribute to changes in circuits and chemistry. This offers an account of how a brief frightening event can produce a response that continues well beyond the original danger.