Sunday, February 12, 2006

I Am a Lizard

I realized I am a lizard, a dog, a rabbit, a human, and a monkey, not necessarily in that order. What do all these vertebrates have in common? Parts of our brain that function the same and associated behaviors.

An audible alarm on my computer announces incoming email. After months of email correspondence with a long-distance lover, with emails arriving throughout the day, I discovered that I was Pavlov’s dog. I became so conditioned to that email notification alarm that it would elicit an instant response of excited and pleasurable anticipation. I found myself smiling at the sound of it; our emails, encompassing a myriad of topics beyond personal matters, were interesting, enjoyable and sometimes playful. I even woke from a sound sleep upon hearing the alarm. There I was, Pavlov’s dog salivating and wagging my tail in the anticipation of his emails every time I heard the alarm emit from my computer.

Named after a Russian psychologist, Pavlovian conditioning is an example of procedural memory, or a memory that is not consciously perceived. For example, Pavlov’s famous dog was repeatedly shown food and soon started to salivate in anticipation of eating. Pavlov then rang a bell before he showed the dog his food, and repeated this sequence numerous times. Eventually the dog started salivating when the bell rang before the food appeared, and even in the absence of food. The dog was conditioned to associate the bell ring with the probable arrival of food. This conditioning does not require a subject to make a conscious association between the two stimuli.

After a traumatic and emotional termination of the relationship and emails from him ceased, that email alarm elicited a very different response. Emails from other sources continued to arrive with the email alarms sounding loud and clear in the house. My immediate reaction the first time was that old Pavlovian conditioning strongly overlaid with a stress response: fight-or-flight. My heart raced, my skin broke into a sweat, muscles tensed and my gut clenched. I froze in the kitchen ready to cry, fight or flee. For a nanosecond in time I was a dog and a lizard. Then my conscious awareness saved me from running out of the house.

What occurred was an automatic reaction to conditioned memories and memories of emotions. The Pavlovian pleasurable anticipation was replaced immediately by an overwhelming stress response consisting of physical manifestations and emotions. The extent of that second response kicked my conscious awareness in enough to comprehend what had just happened. After that realization and an exclamation of “Holy shit!” I knew I needed to change the audible alarm of my email notification.

Perhaps the curse of a scientist is knowing the course or cause and effect of even the most mundane occurrences around us, but unable to stop or avoid many of them. I recognized immediately after my entire brain processed this course of reactions that my lizard brain was stronger than I thought. I laughed with an image of my tongue flicking out to catch a fly. And then shut off the audible email notification on my computer.

What did occur here? A signal from the environment activated different parts of my brain that are prepared to respond according to preset or unconscious schema. The immediate emotions and feelings were a response to innate and preconditioned processing by parts of my brain, whereas the awareness of the feelings resulted from another part of the brain that modulates the former. But where’s the lizard?

Before I continue, I will address a few terms here. Emotions are a collection of responses. They are automatic physiological manifestations, such as spontaneous facial expressions, changes in heart rate, and a queasy stomach. They are unconscious or pre-conscious and programmed in our brains. Feelings go beyond the emotions because they are complex interpretations that image the emotions or responses. Only when the core consciousness is aware of the entire set of the afore phenomena can we know the emotions: feel the feelings. Consciousness is not needed for the early responses, but to know that I have a feeling the process of consciousness is required in the aftermath of the processes of the emotions and feelings.

Lizards and humans

Certain behaviors are pervasive across all vertebrate species. Fear is a perfect example; it helps us stay alive. The way our body responds is similar to the way other animals act when they are afraid. We have an evolutionary fear system that detects danger and responds to it in an autonomic way. When an animal senses danger, the fight-or-flight response is automatic: it automatically startles or freezes. Other physiological responses occur, such as changes in blood pressure and heart rate, blood rushes to the skin, sweat, breathing quickens, and nerves in the stomach cause the gut to constrict. This is the classic stress response experienced when a mouse sees a cat or we see a snake. It is a process of unconscious emotional reactions; they can be innate or pre-conditioned.

Let’s take a look at the pathway involved here in evolutionary terms. In the early 1970’s, neurologist Paul MacLean proposed three evolutionary levels of anatomical and functional brain development. The core of our brain –the brain stem and cerebellum- is the oldest of the three areas. MacLean coined it the ‘reptilian’ brain, first appearing in fish nearly 500 million years ago. It developed in amphibians and advanced in reptiles ~250 million years ago. The reptilian brain controls vital body functions such as heart rate, breathing, body temperature and balance. It reacts aggressively and autonomically in the interests of self-preservation.

The next layer is the early mammalian brain (paleomammalian) and contains most of the limbic system. First appearing in small mammals about 150 million years ago, this region includes the olfactory portions, the hippocampus, hypothalamus and the amygdala. The latter is an important component of the limbic system and is a central axis in the emotional circuitry of the brain. It records memories of behaviors and their consequences (emotional memory). Thus reactions are more complex and varied than those of the reptilian brain.

The most advanced portion of the brain is the neocortex (neomammalian) which began its expansion in primates ~2-3 million years ago. It is the large convoluted bulk of the cortex and mediates the emotion of both the reptilian and the paleomammalian limbic system by cognitive functions. The dual hemispheres of the neocortex are responsible for the development of human language, abstract thought, imagination and consciousness. Its flexibility has almost infinite potential for learning abilities. It is also the ‘hungriest’ part of our brain, requiring a large portion of our daily circulating glucose for full function.

Although these three parts of the brain do not operate independently of each other and have numerous interconnections through which they influence each other, sometimes the quick and dirty system of the reptilian and limbic parts of the brain allow us to act first and think later. Evolution and conditioning do the thinking for us, sometimes freezing first, then run, fight, jump or hold still. The neocortex also processes the stimulus, but it takes a bit longer. Its not needed for some of the emotional learning, such as that involved in the fear system. So we can have emotional reactions to something without knowing what we are responding to. This is the unconscious processing of emotions. But we need the neocortex for the higher-level perception that distinguishes and rationalizes the feelings about the emotions.

Recent studies with humans subjects conditioned with sound and mild shock showed that the human brain operates basically the same way as the rat brain, or the brains in dogs, rabbits, cats, primates, birds and lizards. To quote neuroscientist Joseph LeDoux*:

In this sense, we are emotional lizards. We’re running around with an amygdala that’s designed to detect danger and respond to it. Obviously that’s not all there is to an emotional reaction, but it’s the way the emotional reactions get triggered. This system is very efficient, and it hasn’t changed much in terms of how it works. What has changed, of course, are the kinds of things that will turn it on, the things that humans have learned to respond to that have the same effect on us that seeing a cat has on a rat.”

What occurred in my kitchen that day was a complex series of emotions and feelings. The sound of the email notification triggered a conditioned response based on emotional memories (pleasurable anticipation) but were immediately followed and overwhelmed by more recent conscious (memories about the emotional memories) and unconscious emotional memories associated with shock and stress. This triggered my autonomic and endocrine systems which caused me to freeze, my heart rate to race, my body to break out in a sweat and to gasp. Then my neocortex kicked in and processed all this with a resounding self-aware “Holy shit!” as I realized the intensity and complexity of my responses and feelings. I laughed at the magnitude and quickness of this process, exclaiming outloud “I am a lizard!” and decided to change the email notification sound on my computer.

* LeDoux, J. 1996. The Emotional Brain: the mysterious underpinnings of emotional life.

1 comment:

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