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| Insane in the membrane. Insane in the brain. |
But
still, some dogs just aren’t right. From reactivity to anxiety to
aggression, there are dogs who just don’t function well despite
training classes and socialization and good intentions. Sometimes
this is because the dog’s brain just isn’t wired right. Now, I’m
no neuroscientist, but I do play one on the internet. And today, I
want to share how stress can affect a developing brain, and why doing
everything right may not matter if your dog came from a
less-than-ideal background.
Science
is pretty clear that stress in young mammals influences both brain
development and physical growth. Stress can come in many forms. In
children, there’s the obvious abuse and neglect, but then there’s
the less obvious: poverty, housing instability, witnessing violence,
growing up in bad neighborhoods, malnutrition, and so on. These
chronic adverse events that the child and/or his caretakers have no
control over changes the way the brain grows.
For
dogs, such toxic stress during the early developmental period can
happen in a number of ways. Puppy mills – and other deprived
environments – are an obvious example of a stressful environment,
but growing up in a shelter or a rescue can disrupt the growing
brain, too. Sudden separations from human or canine caretakers,
frequent change, environments characterized by sensory overload, and
long periods of confinement are stressful. And even dogs from good
breeders can be subjected to stress in the wrong circumstances: too
much handling by a child, being harassed by another resident animal,
or chronic medical problems on the part of the pup or the mother.
This
does not mean that every dog from a puppy mill or rescue is going to
have behavior problems. Indeed, if that were the case, people would
stop getting dogs from these places. Some dogs have genes that are
“turned on” by stressful events more readily than other dogs,
making them more susceptible to the effects of stress. We see this in
human children too; for some, stress creates a resilient brain, while
in others, it creates a brain vulnerable to a host of behavioral
problems.
So,
just how does stress affect the developing brain?
First,
it’s important to understand that stress is a normal part of
functioning, and that overcoming a challenge creates a stronger brain
and a sense of mastery. It is therefore important that children and
dogs experience occasional frustration in doses they can overcome so
that they develop the neuronal connections needed for a healthy
brain. Not only is it impossible to shield your young mammal from
stress, it’s inadvisable.
When
a mammal experiences stress, the brain releases chemicals like
cortisol and adrenaline. These prime the brain to be able to respond
to potential danger. Once the stressful event is over, the chemicals
dissipate, and the brain returns to its normal state of functioning.
However, when stress is either prolonged or recurrent, the brain
never fully gets rid of the stress hormones. This changes the way the
brain develops.
Recent
research has shown that there are notable differences in the amounts
of gray matter vs. white matter in the brains of overly stressed
children as opposed to those who experience normal amounts of stress.
Basically, gray matter is responsible for higher functions like
thinking and decision-making, while white matter is what connects the
various brain structures. Chronic stress seems to create more white
matter, which naturally results in less gray matter. In turn, this
reduces the volume of brain structures that allow for rational
thought in the face of potentially threatening events. At the same
time, that increased white matter basically creates a short circuit
in the brain. Even when there isn’t a stressor present, the brain
may continue to respond as if there is. This tends to cause
overreactions to things that aren’t actually dangerous.
Not
only are the connections stronger between the lower brain structures
that control emotional responses, but some brain structures become
overdeveloped. The amygdala and other associated limbic system
structures – which are associated with stress responses – are
often enlarged, while the hippocampus and other higher brain
structures – responsible for problem solving and rational thought –
are smaller.
The
end result is a brain that idles on high. It is more easily hijacked
by stress, and will respond with more frequency and intensity to
smaller stressors. The circuitry activates longer, and the recovery
time takes longer.
In
other words: your reactive dog’s brain? Is not like your normal
dog’s brain. And as a result, his ability to process things that
happen to him and respond to the world around him is going to be
impaired. It’s not only unfair to expect him deal with the world
without additional support, it’s probably impossible.
That’s
not to say that your dog can’t improve. Science has shown that the
brain is incredibly plastic – it can rewire itself and become more
functional – but this takes a lot of time and effort. And even with
the best interventions, we don’t know yet if all the scars left on
the brain by stress can be erased. Sometimes adjusting the
expectations we have for our reactive dogs is the kindest thing we
can do.
Sources:


