Numerous domestic dogs are contributing to a citizen science study that
aims to better understand how memory and cognition change as we age.
Hana did well on her memory exam. The three-year-old Cavalier King Charles
spaniel had to recall which of three identical boxes housed a reward after
examining the contents of each one; a job she swiftly mastered after just a
few tries.
Scientists are learning something else thanks to Hana and her human partner
Masami Shimizu-Albergine of Bainbridge Island, Washington: when dog
intelligence peaks and how it decreases with age.
Hana is a member of the Dog Aging Project, a citizen science project
started in 2014 that already includes close to 40,000 domestic dogs. One of
the project's two major objectives is to comprehend the biology of aging in
companion dogs, according to cofounder and codirector Matt Kaeberlein, a
pathologist at the University of Washington in Seattle who specializes in
aging. The alternative is to take action.
The University of Washington and Texas A&M University effort will
monitor several facets of dogs' life over time through veterinarian records,
DNA samples, health surveys, and cognitive assessments like Hana's
treat-finding task. Hana will take part in fewer, more narrowly focused
research and thorough assessments than the other canines. From all of
information, researchers seek to identify trends and establish connections
between lifestyle choices and health from early development to old
age.
The Family Dog Project was started in the 1990s at Eötvös Loránd University
(ELTE) in Budapest to investigate "the behavioral and cognitive elements of
the dog-human interaction," and tens of thousands of dogs took part during
the course of the project's existence. The scientists anticipate that
working with such a sizable combined group of dogs would enable them to
elucidate the genetic and environmental variables that influence how long
dogs live and how much of that time is spent in good health. The two teams
have started working together across continents.
Hana, a three-year-old companion dog, is one of the hundreds of canines
taking part in the Dog Aging Project. She is shown here with her owner
Masami Shimizu-Albergine.
Given that there are probably hundreds of millions of dogs kept as pets
worldwide, it is crucial to understand how they age in order to enhance both
their quality of life and the care they get. Following the lives of some of
these canine partners, however, may offer insights into how to age more
healthfully as well as information about our own aging brains.
Studying the biology of human aging is difficult since the process lasts
for many decades. It entails keeping track on individuals for 50, 60, 70, or
even longer, which may be time-consuming and costly. Dogs, on the other
hand, age fast. For those who adore their pets, this is terrible, says dog
lover Kaeberlein. However, it makes dogs a great model system for research
on aging. (Though Bernese mountain dogs have an average lifetime of seven
years and Chihuahuas nearly double that at 13 years, it may be said that a
70-year study of humans is about similar to one dog decade.)
There are additional benefits to studying dogs as well. They are superior
animal models to the inbred mouse strains that are generally employed in
aging studies due to their genetic variability. And while though researchers
prefer to examine their subjects in the controlled setting of a lab, the
fact that humans and their pets share homes with a wide range of conditions
is really helpful when trying to draw conclusions about human aging. A
complicated human world cannot be duplicated in a lab setting. However,
according to Kaeberlein, there is no need to if you study pet dogs.
Wrapping up
According to ELTE ethologist Enik Kubinyi, who has spent over 30 years
researching canine cognition, scientists had long seen dogs as "manufactured
creatures" with abnormal behavior. In fact, Kubinyi claims that when the
Family Dog Project—to which she contributes—was developed in 1994 by a group
of Hungarian ethologists, many people believed the concept was absurd.
However, opinions are beginning to shift. Numerous research have examined
dog behavior, genetics, and neurobiology so far, across breeds and
throughout time.
The Dog Aging Project, on the other hand, looked into the effects of the
medication rapamycin in a small-scale clinical study including 24 companion
dogs. The drug has been found to lengthen longevity in yeast, roundworms,
fruit flies, and mice. It is also used to treat cancer and prevent organ
rejection in humans. When compared to dogs that received a placebo in that
2017 trial, pups who had taken rapamycin exhibited enhanced cardiac
function, according to heart scan results. The Dog Aging Project has since
started a larger, longer-term rapamycin experiment as part of its objective
to learn more about the biology of how dogs age.
That includes having a healthy brain. According to comparative psychologist
Evan MacLean, director of the Arizona Canine Cognition Center at the
University of Arizona in Tucson and a partner in the Canine Aging Project,
"there's a lot we really don't know about how dog cognition evolves with
age." What does typical cognitive aging entail? Do early memory problems
indicate dementia later on? The longer-term objective, according to MacLean,
is to find early therapies that could stop the decline.
A battery of canine cognitive tests based on research on rodent cognition
is being developed by MacLean's collaborator Emily Bray, a psychologist at
the University of Arizona and the service-dog organization Canine
Companions, in order to achieve this goal (it includes the "1-2-3-treat"
test that Hana completed). For some of these tests, the canines must learn
how to communicate with touch displays, another pervasive object in the
human world.
Dogs are trained to link three vividly colored, aggressively patterned
squares with a particular area on the screen in one memory and learning
test, for instance. Dogs are placed in front of a screen within a wooden box
for the test, and they are instructed to contact the square with their noses
only when it is at the proper location. However, they also focus on
abilities that may deteriorate with age and are reliant on brain areas
impacted by Alzheimer's disease in humans and its canine counterpart, canine
cognitive impairment. Dogs' memory and learning skills will be evaluated on
a regular basis to examine how they hold up over time. Based on the waving
of their tails, dogs learn to adore screen time.
As part of a research at the Arizona Canine Cognition Center, Kai the
dog selects a symbol from a touch screen. The goal of the study is to
examine changes in canine memory and cognition throughout time.
In a different study, the two citizen science initiatives collaborated and
discovered, using pet dogs donated post-mortem, that older dogs and those
who displayed dementia-like behaviors had higher levels of amyloid-beta, a
misfolded protein that is also linked to Alzheimer's disease in humans, in
their brains. Mice that have been genetically manipulated to develop
dementia have been utilized in the majority of animal investigations of
Alzheimer's disease. But because canine cognitive failure appears to develop
spontaneously in dogs, just as it does in people with Alzheimer's, the
researchers are hoping that their continued study of dog brains may also
provide insights that help comprehend the human condition.
Life of a dog
One benefit of following so many dogs over their careers is that
researchers will have access to enough information to begin establishing
links between the way that dogs live and age and their settings, habitats,
and behaviors. Physical exercise, which has been demonstrated to be
protective against brain aging in humans and several other species, is one
aspect they are paying special attention to. Emerging findings from a survey
of Dog Aging Project participants imply that the same could apply to
canines. Some of the participating canines will wear a gadget "like a
Fitbit, but for a dog," according to Bray, to test the connection.
Calorie restriction is also a popular issue in aging research since studies
on lab mice have shown that eating less and regulating when one eats can
lengthen life. The situation is more complicated outside of a lab's well
regulated environment. Bray is in charge of a research that compares the
feeding behaviors of over 10,000 dogs of various ages, sizes, and breeds in
an effort to shed some light on the situation.
According to the findings, 8 percent of the dogs that were fed just once
per day on average had better health. Compared to dogs fed twice a day or
more, these single-meal pups had less gastrointestinal, dental, orthopedic,
renal, and other diseases. Additionally, they marginally outperformed them
on cognitive tests. According to Bray, it's unclear how eating less
frequently enhances cognition, but the impact was notable: it was about the
same magnitude as the difference in the average cognitive scores of 7- and
11-year-old dogs.
So what changes do dogs' brains undergo as they age? Scientists in Hungary
working on the Family Dog Project are monitoring that. EEG scans of dogs'
brains and even training them to remain still within fMRI machines have
shown that, like humans, the size of dogs' brains decreases with advancing
age.
In a related imaging research, Colorado State University veterinary
neurologist Stephanie McGrath conducts MRI scans on participants in the Dog
Aging Project in search of characteristics that may link brain shrinkage and
other physical changes to dementia in senior dogs. She finds it most
fascinating because her research implies MRI might someday be utilized as a
tool for early detection.
New tricks
Ageism and a dismissive attitude have long been present in society toward
the elderly. Older dogs are not any different, according to veterinarian
Patrizia Piotti of the University of Milan and former team member of the
Family Dog Project. While it may be more difficult to teach an old dog a new
skill, it may enhance their cognition to keep trying, according to a body of
studies on problem-solving, memory, and attention in dogs as they age.
In reality, according to experts from the Clever Dog Lab at the Messerli
Research Institute in Vienna, not all new skills are more difficult for
senior dogs. Zsofia Virányi, an expert in comparative cognition, and Durga
Chapagain, a former student, administered 119 pets canines a battery of 11
cognitive tests that involved activities including playing, viewing photos,
finding concealed food, and manipulating toys. They discovered that
characteristics including the capacity for problem-solving, boldness, and
fun decreased consistently with age. However, older dogs fared as well in a
challenge that required them to make eye contact with the trainer after
discovering and eating a piece of sausage that had been placed on the
floor.
According to Chapagain, this proves that we shouldn't undervalue elderly
dogs' mental capabilities. Older dogs may have the same drive to continue
learning as younger pups, but "humans are less willing to play with them,"
she adds (at least when sausage is involved). They are considerably more
powerful than we realize. Throughout their lifetimes, owners should continue
to provide their canine friends with cerebral stimulation such as trick
training and nose work such as concealing goodies for a game of "sniff and
seek," says Piotti. "Anything that causes the dog to pause for a
moment."
Inside the brains of aging dogs
Reviewed by lilit
on
August 04, 2022
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