Connecting the Dots: Part 2
© James Barnhart 2007
A laboratory rat was subjected to electric shock accompanied by an audible tone. Very soon, after repetitive tone/shock cycles it displayed obvious fear to the tone, even without the shock. This is a simple example of an auditory association. But even after the auditory cortex was removed from its brain, effectively rendering the rat absolutely brain deaf, it still displayed marked fear at the sounding of the tone.
[1] This correlates with the explanation of the neural circuitry in my article “Connecting the Dots”. Before the signal from the eyes and ears is sent to the visual or auditory cortices, the amygdala receives (from the thalamus) it’s 12 millisecond flash signal first to assign an immediate evaluation and response in case it’s a “fight or flight” scenario that cannot wait for the prefrontal lobe to respond with its reasoning about what is seen. The net result being, even with a piece of the neural machine missing or damaged, diseased or underdeveloped, the brain still functions albeit in a different (not necessarily reduced) capacity.
One of the many neurological and physiological aspects of my driveway shooting was the experience of auditory exclusion. Gunfight survivors often describe the feeling of being in a tunnel where everything else but the source of their immediate fear was “shut out”. This is why it is important to break tunnel vision by looking left and right immediately following a firing cycle to detect additional threats that may have been converging on you while you were engaging the primary attacker.
My first indication of auditory exclusion came just moments after I stopped firing. Both assailants lay bleeding, I had taken cover against the bed of my truck and could hear them yelling and crying. It was then that I was almost overwhelmed by the cascading return of my perceptible hearing. There were all the sounds of the environment; a streetlight buzzing, tree limbs rattling and autumn leaves swirling in the breeze. There was a baby crying somewhere in the distance to my right and I could hear the voices of the fleeing people at the apartments down the hill from my house.
The din of all this subtle ambient noise was not enough to trigger an immediate response from my amygdala, but was enough to cause me to start to feel panicked because I was still fearful of a second attack and was not able to process each sound fast enough to definitively rule some of them out as additional attackers. Or so I thought.
In reality, my amygdala was sorting out the sounds in as little as 12 milliseconds after the sound waves caused a signal to be sent from the nerves attached to my inner ear to my thalamus. Since the sounds carried no memorable association with aggression to my amygdala and its memory partner, the hippocampus; there was no fight or flight response initiated. However, the sound signals also traveled to my auditory cortex which translated them to my prefrontal lobes for reasoning.
The rational vetting process of the “thinking brain” is too slow to satisfy the urgency of what may have been another instant life or death scenario, resulting in my increased inklings of panic. I now know that had there been anything that sounded like an immediate threat; my amygdala would have jerked me into action well before my prefrontal lobes could have issued a rational decision about how to handle the threat.
The exclusion of reality, so to speak, is not exclusive to the sense of hearing. The lag after the amygdala response of rational comprehension is also responsible for the often described slow motion perception in an extreme duress situation. The amygdala is commanding response faster than the prefrontal lobes can process an understanding of what the visual cortex is saying the eyes are seeing. Case in point; the passenger in my shooting did not begin to get out of the car until after I had engaged the driver. Seeing the passenger’s movement to my left, I swung towards him and fired. I thought I had only fired three rounds at the passenger.
In reality, I got off five rounds. He was just starting to step out as I started driving my gun in his direction and I do not remember firing before seeing his torso stand erect, but I put two rounds on him through the windshield of the car as he was just starting to rise from his seat, then three more directly into his torso after he was clear of the windshield. I also remember feeling extremely lethargic in action, like a dream that wouldn’t let me react as fast as I felt was necessary. I couldn’t pull the trigger fast enough to mitigate the threat. It felt like I was keeping time with a metronome four feet in height. However, witness accounts put the entire duration of gunfire at approx five to seven seconds, including the three rounds they got off before I returned fire. I expended 12 rounds total; seven on the driver and five on the passenger. So what was actually happening was that I was reacting faster than I could effectively “think”. I was unaware of the windshield shots until much later when talking with detectives handling the investigation. In his book, The Gift of Fear, Gavin DeBecker writes, “The brain is never more efficient than when its host is at risk”. This statement is nearly absolute in truth. My brain didn’t bother to take the time to let me fully perceive what was happening, it just took over my body and saved itself.
The latency of the rational response offered by the frontal lobes following the immediate survival response of the amygdala is common in incidents of high emotion such as fear or anger, but presents as a double-edged sword. Except in situations of extreme stress, the initial reaction of the amygdala (felt as compelling emotion) is subdued by the reasoning of the pre frontal lobes, our “thinking” brain.
The amygdala actually issues a second emotional value to the result of the pre frontal lobes’ perception. For example; you jump at the sight of a rubber snake in a drawer (fear), but laugh at yourself (humor) after realizing (prefrontal reasoning) you’ve been had. The amygdala initially made you jump from fear of being bitten by what it and the hippocampus knows is a dangerous entity and then made you laugh by assigning an emotion to what you realized was actually in front of you and how it must have made you look. After the initial startling, the prefrontal lobes catch up and stop the amygdala from continued overreaction through reasoned qualification of the threat.
The other side of this blade is that the survival reaction the amygdala commands is indiscriminate and can be sloppy in nature until the prefrontal lobes can take over with what they have gleaned from the situation. The tragedy of Matilda Crabtree is such a case in point. Mr. Crabtree had returned home and upon entering the house heard a suspicious noise. His 14 year old daughter, Matilda, was supposed to be away for the evening and when she jumped out to scare him as a prank, he fatally shot her in an instant of amygdalaic reaction that was completed before his prefrontal lobes could make the distinction and pull his finger from the trigger.
The quantum increase of the intricacies of our modern life and its exponential layering of economic and social interactions has also quickly outrun the sometimes all or nothing response our brain offers when the emotion is instant and extreme, making us look as though we just “snapped”.
Now consider having diminished capacity in your prefrontal lobes. You may not rationalize that the rubber snake is rubber and therefore would not be able to stop the initial overreaction in a normal timeframe and continue on with your actions as though scripted by Monty Python himself. Inversely, with diminished capacity in the amygdala, you could be like “M”. “M” is a woman whose case is described in Daniel Golemans book, Emotional Intelligence. Because of damage to her amygdala, she felt no fear and appeared to have ice water in her veins. Goleman writes, “You could put a gun to her head and she would know that the gun was something to fear, but she would feel no actual fear of the gun”. Or, consider a case of an amygdala so excited by its stimuli (as in Post Traumatic Stress Disorder) that it crosses into the realm of hallucination or produces a reaction that the prefrontal lobes may be powerless to quell whether by result of brain damage, malformation, etc.
This is where we’ll start looking at the next dot of this picture; understanding the criminal mind, for this is the root of the need to carry a weapon in the first place.
April 15, 2010- -
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