SyncThermology Blog

Your animal’s primitive brain and pain

Monday, February 12, 2018  ‹ Back To Latest News List

 

 

This blog has been written by Kat Kuczynska based in the North West. Kat works with both Equine and Canine patients and is part of our central team focussing on training, research and team support.

In terms of evolution, pain could be described as one of the best inventions because it offers the promise of safety and a chance to pass on DNA through the generations. Pain functions as an automated feedback system living deep within the substance of the brain. In fact, of all the areas of the brain (from an evolutionary perspective) the Limbic System which controls and responds to pain, is said to be one of the oldest and most primitive.

The Limbic System has many functions, but the ones I want to highlight in this blog are: processing and responding to pain, controlling movements based on previous learning and how it plays a significant role in creating emotions and feelings. Pain is a highly primitive, complex sensation, deeply rooted in a species’ survival instinct and tightly linked to emotions.

We all know that Osteoarthritis causes pain, but its high prevalence across all species has made this condition “feel” somewhat - normal, common and subsequently simple. It is often thought of as a deteriorating condition treated with periodical pain medication and for which there is little treatment. This couldn’t be further from the truth.

We see a lot of animals affected by Osteoarthritis in both SyncCanine and SyncEquine. Owners frequently report a sad, rollercoaster journey trying to navigate their beloved animal through the treatment. They describe trying medications with various degrees of success, periods where the clinical signs improve then worsen and feeling “stuck” and helpless watching their animals deteriorating despite various interventions. Some owners struggle to break this vicious circle of pain, medications, improvements, further lameness and further medications and get used to this as a new way of life with their animal. Osteoarthritis is the leading cause of disability due to pain and is an immensely complex disease so coming to terms with the diagnosis and understanding the options available might be quite overwhelming.

Going back to the Limbic System in relation to Osteoarthritis. Negativity bias is yet another, primitive adaptation of the brain designed to keep animals (including humans) alive. I use the phrase ‘negativity bias’ in the context of a negative (or painful) experience being more powerful than a positive one.

Let’s translate this into the pain felt by arthritic patients. Osteoarthritis causes pain. The animal’s brain remembers this pain and very quickly learns to adapt and/or avoid it. The Limbic System controls the response in reaction to pain, movement, previous experience, emotions and sensations. We see this response as secondary changes and subtle gait alterations which are extremely difficult to measure objectively – especially in the initial stages of pathology.

The longer an animal is subjected to pain the more pronounced the negative learning is. I think we can go as far as calling it negative learning because the brain becomes sensitised to the sensation of pain.

Why would that be?

Well, because pain doesn’t exist on its own. It’s created by the brain based on the interpretation of incoming signals or stimuli. Sensitise the brain and it will interpret other signals inappropriately. The brain can essentially read other previously not-painful signals, such as mere joint loading, as pain.

I referred to the pain response being a primitive evolutionary development, but what effect does it have? The term ‘primitive brain’ refers to the most instinctive brain functions which are shared by all reptiles and mammals, including humans. It’s the most powerful and oldest of the coping functions for instinctive survival. And Osteoarthritis affects and stimulates this part of the brain. That’s why controlling it is so difficult. Whatever interventions we use, we are against millions of years of adaptations and survival mechanisms which have had a very, very long time to perfect themselves. To successfully treat Osteoarthritis, we need to address the actual pathology and then trick the brain to “forget” about and move on from the pain it has been interpreting before. It’s the latter which is usually the challenge!

There are diverse types of pain and pain syndromes, the processes involved are extremely complex and often intertwine. We should start looking at Osteoarthritis as a cocktail of acute (or adaptive) and chronic (or maladaptive) pain that is mixed with various pathological changes such as cartilage erosion, inflammation of the synovial fluid, swelling of the joint, scar formation and many others. Each of these conditions on their own produce its own set of challenges. Put them all together and you have Osteoarthritis which left to its own devices will fuel its own progression.

It is simple? No! But advances have been made in understanding the complexity of the problem our vets, owners and animals are dealing with. There’s a glimmer of hope for a “cure”.

In the next blog we will delve further into the latest recommendations for the treatment of Osteoarthritis.

 

References:

  1. Neogi T. The epidemiology and impact of pain in osteoarthritis. Osteoarthritis Cartilage.
  2. Neogi T, Zhang Y. Epidemiology of osteoarthritis. Rheum Dis Clin N Am. 2013.
  3. Kuyinu E, Narayanan G, Laurencin C. Animal model of osteoarthritis: classification, update, and measurement of outcomes. 2016
  4. Bekoff M. “Article Details” Do Animals Have Emotions? Of course they do!p., n.d. Web. 27 Apr. 2016.
  5. Fazio K | For Inside Jersey. “Dogs Suffer from Many of the Same Psychological Disorders as Humans” NJ.com. Institute of Neurological Diseases, 07 Dec. 2010. Web. 27 Apr. 2016