Fear is the brain’s hard-wired survival mechanism. There are three key players in this system:
• The thalamus is your brain’s window to the world. It receives and processes at a low level sensory input and sends messages to:
• The amygdala, which scans the information for threats and musters a full body response if danger is detected, and
• The prefrontal cortex. This higher level brain area integrates the sources of information and analyzes them in light of past experiences. It can keep the fear response from spiraling out of control by inhibiting the amygdala.
Click here to view these players in a rotating 3-D brain model.
The amygdala gets sensory messages from the thalamus first because it is connected along a shorter, narrower pathway than the prefrontal cortex. Plus, it receives only about five percent of the sensory input. This is a good thing. Otherwise you’d likely be overwhelmed with panic because the amygdala can unleash a powerful reaction. It prepares you to flee, fight or freeze.
• Your heart starts beating rapidly
• You start taking quick, shallow breaths and sweating
• Your hearing and vision narrow down to pinpoint focus on the perceived threat
The prefrontal cortex receives the other 95 percent of the sensory input from the thalamus about a quarter of a second later. This brief lag with its higher functioning allows reason and experience to take hold, to expand your realm of explanations, change your perception and transform fear into something more logical. For example, realizing the banging of your front door at night is caused by the wind, not a burglar, and so you latch it tight rather than empty a shotgun round into it.