Walking the Dog, Prefrontal Cortex Engaged

A favorite walk: the dog park.

A friend and I were recently at a local dog park, walking his Sheltie and Australian shepherd, and my two standard poodles. Our dogs are not daily visitors to the dog park, and while his dogs are well-behaved and subtle in their approach to other dogs, my poodles’ enthusiasm is not always in their best interest.

In addition, one of my dogs seems to take issue with certain of the protection dog breeds,  like German Shepherds, as well as some of the sled dog breeds. Generally, if a dog has pointed ears, I am on the alert for bad behavior.

For that matter, the protection dogs don’t seem to much care for fluffy, bouncy poodles. Annoying, you know? A dog’s trying to keep order and make the world safe, and here comes that poodle, bouncing along without a care in the world. There’s a lot of danger out there and the poodles are simply not paying attention. They jog along meeting people and dogs like they are running for mayor; darn poodles.

Occasionally it has seemed that the attitude problem is not exclusive to my dog.

People often say, “Oh, standard poodles are such smart dogs”. But you’d think a smart dog would not choose a big, guard dog breed with which to make trouble.

So we are walking the large circular path at the dog park and catch up to a woman walking her American Eskimo dog. I tense considerably and mutter to my friend, “This could be interesting”. As we pass, I say hello and things are going fine because her dog is distracted by something to her left as we pass on the right.

Then it happens. My dog “snarks” at the Eskimo dog, a head thrust towards the dog’s side, with a short bark, as if to say “Hey, look over here”. It’s the dumbest thing in the world and deserves the response it gets. The other dog wheels towards mine, teeth barred.

The other dog’s owner yells at him,  “Stop; leave it!”

I apologize to her, scold my dog and quickly move on. We don’t meet them again the next time around the circle; apparently they’ve left. The rest of our visit is uneventful and I’m thankful the negative interaction was minimal.

At home 90 minutes later we’re sitting down to coffee when I notice a bloody spot on my dogs flank. I jump up to inspect, saying, “Wow, that dog bit Oli,” to which my friend replies, “Yeah, he had a hold of him…didn’t you see it?”

The dogs were right there in front of me, no obstructions. I recall seeing the other dog turn towards Oliver and worrying that a serious dog fight was about to start. But I have no memory of any contact occurring.

This phenomena, seeing but not recalling the dog interaction, could be attributed to the effect of stress on my prefrontal cortex.

Stress and the Prefrontal Cortex (PFC)

Dr. Amy Arnsten explains how stress affects the PFC in a June 2009 Nature Reviews in Neuroscience review,  “Stress signaling pathways that impair prefrontal cortex structure and function”. In the abstract Arnsten writes,

“The prefrontal cortex (PFC)—the most evolved brain region—subserves our highest-order cognitive abilities. However, it is also the brain region that is most sensitive to the detrimental effects of stress exposure.”

And it doesn’t take much stress to elicit the detrimental effects. “Even quite mild acute uncontrollable stress can cause a rapid and dramatic loss of prefrontal cognitive abilities.” In fact, prolonged exposure to stress can actually change PFC structure.

About the PFC

The PFC regulates thoughts, actions and emotions via an extended network of neurons; these neurons maintain information in the absence of environmental stimulation, something neuroscientists call “working memory”, meaning not only the ability to keep in mind an event that just occurred, but also to recall information from long  past events and to use the information to regulate behavior, thoughts and emotions.

The PFC is also acts to inhibit inappropriate actions and promote actions revelant to the task at hand. It allows us to shift behavior with changing circumstances, such as altering attention and decision making as conditions change. In addition the PFC, in monitor conditions, allows the insight that we are in error and need to shift strategies.

As the review states, “All of these abilities depend on proper PFC neuronal networks, which are highly sensitive to their neurochemical environment.” Stress can change the neurochemical environment, disrupt PFC network connections and thus impair function.

The PFC has deep connections to brain regions that allow it to, under regular, nonstressful conditions, regulate it’s own catecholamine levels. Catecholamine release in turn optimizes PFC function.

Stress can Block the PFC

However, during stress the amygdala takes over, activating stress-related pathways in the hypothalamus, resulting in high levels of noradrenaline and dopamine release. These chemicals impair the PFC and strengthen amygdala function. In this way, stress impairs PFC abilities like working memory and the ability to regulate attention.

Fortunately  there is a caveat—studies have shown that the vulnerability to stress can vary depending on the subjects’ sense of control over the stressor. Studies have shown that subjects who felt in control of their situation were not impaired by exposure to stress (even if the control was an illusion). On the other hand, subjects that felt out of control in a stressful situation, were often impaired.

Perhaps for our dog park situation, if I was in control (or at least suffered the illusion of control) and believed my dog would listen to “leave it” when it came to certain other dogs, stress would be avoided and my PFC would continue with it’s top-down function. The negative dog interaction might have been avoided (or at least I’d have seen the bite occur).

We will keep the acute stressors to a minimum, or learn to adopt new behaviors to improve our “luck” with other dogs. It worked for laboratory animals (used in the aforementioned studies) and hopefully will work for us.

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Kari Kenefick

Kari Kenefick

Kari has been a science writer/editor for Promega since 1996. Prior to that she enjoyed working in veterinary microbiology/immunology, and has an M.S. in Bacteriology, U of WI-Madison. Favorite topics include infectious disease, inflammation, aging, exercise, nutrition and personality traits. When not writing, she enjoys training her dogs in agility and obedience. About the practice of writing, as we say for cell-based assays, "add-mix-measure".

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