Jen Gunter: What's normal anxiety -- and what's an a...
While fear is a response to an immediate threat that quickly subsides, anxiety is a response to more uncertain threats that tends to last much longer. It's all part of the threat detection system.

Anxiety starts in the brain's amygdala, that alert other areas of the brain to be ready for defective action.

Next, the hypothalamus relays the signal, setting off what we call the stress response in our body. Our muscles tense, our breathing and heart rate increase, and our blood pressure rises. Areas in the brain stem kick in and put you in a state of high alertness. This is the 'fight-or-flight response'.

There are ways the fight-or-flight response is kept somewhat in check, with an area of higher-level thinking called the ventromedial prefrontal cortex. Its a feedback loop that can help keep the response in check.

The hippocampus is also involved. It provides extra context, for example tiger in cages in zoo that you have seen before.

With anxiety, these threat-detection systems and mechanisms that reduce or inhibit them are functioning incorrectly. People with anxiety disorders dont just have a different way of reacting to stress, there may be actual differences in how their brain is working.

One model describes possible mix-ups in the connections between the amygdala and other parts of the brain. The pathways that signal anxiety become stronger, and the more anxiety you have, the stronger the pathways become.

Reseaches show that our brains have the ability to reorganize and form new connections all throughout our lives.