Humans and worms have very little in common; ranging from differing complexity in our genome sequences to the physiology of the two animals, there seems to be nothing of note that we share. Even from a behavioral standpoint, we are nowhere near similar; humans have developed an interpersonal societal web of interaction of unprecedented magnitude in comparison to other animal species across the entirety of recorded life on earth. However, these two drastically different animals share one similarity that is nothing short of shocking: conscious, associative memories.
Recently, scientists Dr. Alon Zaslaver and Dr. Yifat Eliezer, hailing from the Genetics Department of Hebrew University of Jerusalem, published their findings on the ability of worms to establish associative memories (memories associated with a particular sound, smell, taste, or other identifiable sensory form) and its implications in the human world. Zaslaver and Eliezer utilized the C. Elegans worm in a series of experiments strongly resembling that of famed psychologist/physiologist Ivan Pavlov and his experiments regarding classical conditioning in dogs. Essentially, Zaslaver and Eliezer would starve test worms for 24 hours while intermittently spraying them with an odor that the worms liked. This would, assuming all went well, establish a mental link between the odor and starvation. The next day, researchers would provide adequate amounts of food for the worms and spray the same odor used in the starvation period in the day before. Despite being offered food, the worms immediately went into a form of panic, activating stress protective genes in response to what they thought was starvation but was simply a sprayed odor. This established link between an odor and a traumatic experience, such as starvation, gave the scientists ample information to formulate the idea that worms could, in fact, develop associative memories and resulting issues from said memories.
A male C. elegans worm.
Image from Wikimedia Commons
What issues, you may ask? The stress-related genes that were activated in C. Elegans worms in response to the conditioned stimulus (the odor linked to starvation) were enough to scientists to justify the belief that the worms had developed a form of post-traumatic stress disorder. Yes, you read that right. The complex psychological disorder still not completely understood by modern psychologists today is a phenomenon that can occur in a species so simple and rudimentary that it only has 302 neuron cells (in comparison, the average human brain alone has an estimated 100 billion neurons).
Our class has recently done some research in regards to the effects of certain drugs on neurons/neurotransmitters in the body. Similar to drugs, PTSD can impact the release of specific neurotransmitters between neurons that alter behavior and cognition. For example, PTSD can cause panic attacks that are accompanied by spikes in the release of neurotransmitters like norepinephrine and dopamine, as well as serotonin in times of depressive episodes resulting from other PTSD symptoms. Understanding how to reduce the intensity of these neurological imbalances can lead to increased efficiency and effectiveness in therapy and medicines aimed at treating clients suffering from PTSD.
The research conducted by Zaslaver and Eliezer can be helpful in modern research searching for ways to alleviate certain symptoms of PTSD in humans, such as panic-inducing flashbacks as a result of specific stimuli like the smell of gunpowder or loud bangs resembling gunshots or explosions. They hope that a better understanding of what triggers PTSD on a neurological scale can assist in attempts to drive PTSD in humans to extinction, or at the very least a more controlled level of intensity.