00:02Anxiety is a state of heightened apprehension or worry, often related to potential, distant,
00:08or uncertain danger.
00:10It can be accompanied by changes in brain activity, bodily function, and behavior.
00:15Although some degree of anxiety is normal, it can become part of a disorder when it's
00:20excessive, persistent, or interferes with life.
00:24Anxiety involves a network of brain regions that help evaluate possible danger and coordinate
00:29bodily and behavioral responses.
00:31One such region is the amygdala, which helps identify emotionally salient information, especially
00:37cues that might signal danger, and orchestrates responses to threats through its connections
00:41with other brain regions.
00:43The prefrontal cortex may help regulate threat responses by inhibiting them when there is
00:48no actual threat present.
00:49In anxiety disorders, the threat detection system may become overly sensitive, and prefrontal
00:55regulation may be less effective, leading the brain to respond as if danger is present
01:00even when the true threat is low.
01:03Anxiety also involves systems that control the body's stress response.
01:07For example, anxiety can activate the sympathetic nervous system, leading to changes like increased
01:12heart rate.
01:13The HPA axis may also be engaged, leading to the release of stress hormones like cortisol.
01:20Anxiety has been linked to changes in several neurotransmitter systems.
01:23GABA helps decrease neural excitability, and reduced inhibitory regulation by GABA may contribute
01:30to excessive threat-related signaling.
01:33Serotonin helps regulate mood and threat processing, and medications that alter serotonin signaling
01:38are commonly used to treat anxiety disorders.
01:41It's not fully understood why these drugs are effective in anxiety, but it may be linked
01:45to an influence on brain circuits involved in threat processing, emotional regulation, and
01:50stress responsiveness.
01:53Norepinephrine systems can also contribute to the heightened arousal and physical symptoms
01:57retention system associated with anxiety.
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