08/10/2024
🧠To understand your dog’s reactivity, you need to understand the basics of how your dog’s brain works.
A dog may not have the capability of processing higher complex emotions of what humans can, however, you can’t look at a dog and tell me they don’t feel. Of course, they do! Their feelings are just not as complex as humans, but interestingly enough they do process information from all parts of the body similar to our human brains.
So, the brain is made up of soft tissue and nerve cells, and is composed of the cerebrum, cerebellum, and brainstem. These 3 areas of the brain interprets information, controls all functions of the body, and responds accordingly. The brain does not only control physical responses, but chemical ones as well.
Now, let’s go to the autonomic nervous system. The Sympathetic nervous system originates in the spinal cord which is connected to the brainstem at the bottom of the dog’s brain. One of its main functions is to activate the physiological changes that occur during the flight or fight response. This means that the dog's neurotransmitters in the brain send chemical messages to parts of the body to release hormones, and other chemicals to prepare the dog's body for intense action when the dog is experiencing a stressful, or overwhelming event.
The body can fluctuate between flight and fight, and rest and digest. This is because the brain is constantly sending messages and signals from one part to another.
When the dog is feeling heightened emotions such as arousal, stress, happiness, excitement, fear, anxiety, or pain, the brain sends the body messages to react in the following ways:
1. Increased heart rate and respiration,
2. Dilation of eye pupil (to see with more clarity).
3. Inhibition of the lacrimal gland (responsible for tear production and salivation).
4. Dilated airways for increased oxygen,
5. Dilated blood vessels for blood to flow to the muscles.
6. Inhibition of stomach and upper intestinal action to the point where digestion slows or stops (The body can’t process food when in flight/ fight response, it needs to save its energy for survival).
7. The liver releases glucose,
8. The kidneys release adrenaline,
9. Relaxation of bladder.
10. Constriction of blood vessels in many parts of the body.
11. Auditory exclusion (loss of hearing).
12. Tunnel vision (loss of peripheral vision).
13. Shaking.
I want you to keep in mind that all animals (even us humans) are deeply wired to protect ourselves against a perceived threat and each individual has their own interpretations of what is scary and what is not.
For example; I am afraid of spiders and anything that may resemble a creepy crawly, where you may not be bothered at all by the sight of a spider. Fear begins in the brain, and then travels through the body adjusting along the way for the best defence, to run away, or defend oneself as quickly as possible. All these changes happen so fast that the individual wouldn’t even be aware of them or have a chance to really process what is happening.
The fear response starts in a region in the brain called the amygdala. The job of the amygdala is to detect the importance of the stimulus and how much effect it would have on the dog's well-being. This creates a cascade of events which involve the hypothalamic-pituitary and adrenal glands. This is the main driver of the endocrine stress response. The hypothalamus receives information and sends chemical signals to the pituitary gland which signals the adrenal glands to increase the production of cortisol aka “stress hormone”. This stress hormone helps to increase energy in order to deal with a stressful event.
The instant an event is happening it triggers the sympathetic nervous system which signals the adrenal glands to release adrenaline (aka epinephrine) which leaps into action and goes into the bloodstream to increase the blood flow throughout the body which causes quick responses.
The reaction depends on the threat level of the stimulus. The more threatening the stimulus the more intense the response is.
The sight, or sound of something the dog finds scary, intimidating, or threatening creates a stressful event and triggers neurotransmitters in the brain which transmits signals through the synapse from one neuron to another in a chain reaction which changes the way the dog responds to the trigger. These neurotransmitters release a chemical substance at the end of a nerve fibre and these chemicals travel throughout the body and react accordingly.
So now the brain is super alert, pupils dilate, breathing and heart rate accelerates, blood pressure increases, and glucose increases which seeps into the skeletal muscles to provide energy to move quickly.
The takeaway from this is that fear keeps us alive, and it is involuntary. Not one individual has conscious control over it. Even though it is unpleasant and interferes with our everyday lives and functioning, it should be respected not punished.
Maintaining a balance of chemicals in the body is crucial for emotional regulation and stable behaviour. A reactive dog is one who is struggling and may require assistance, possibly including medication alongside a behaviour modification program. This combination aims to establish positive associations and boost the dog's confidence. Veterinary behaviourists specialise in managing a dog's mental state in such cases.
References:
Riva J, Bondiolotti G, Micelazzi M, et al. Anxiety-related behavioural disorders and neurotransmitters in dogs. Appl Anim Behav Sci. 2008;114,168–181.
Beerda B, Schilder M, van Hoof J, et al. Manifestations of chronic and acute stress in dogs. Appl Anim Behav Sci. 1997;52:307–319.
Berteselli GV, Servidaq F, DallAra P, et al. Evaluation of the immunological, stress and behavioural parameters in dogs (Canis familiaris) with anxiety-related disorders. In: Mills D et al., eds. Current Issues and Research in Veterinary Behavioral Medicine. West Lafayette, IN: Purdue University Press; 2005:18–22.
