Category Archives: Biological Sciences

Jogging Your Memory: Aerobic Exercise and Its Positive Implications on Memory Retention

Do you own a pair of runners that haven’t been worn in a while and is now collecting dust on your shoe rack? Science suggests – you may want to put them to use again.

Emerging studies shown that aerobic exercise can slow down aging of the brain and have positive implications on cognitive abilities such as memory retention. Several studies shown that individuals who regularly exercise occupy larger volumes of the brain involved in memory compared to individuals that do not exercise.

What exactly is it about physical exercise that has such an impact you might ask?
Upon light to intense levels of aerobic exercise, the body produces a spectrum of signalling chemicals. One of the chemicals that gets released yields the production of a very important protein called brain-derived neurotrophic factor (BDNF) which gets released in the brain and muscles. When produced in the body, BDNF maintains existing brain cells, promotes the growth of new blood vessels in the brain and encourages growth of the hippocampus, a region of the brain that is associated with memory.

Figure 1. Anatomy of brain. Source: Anatomy & Physiology, Connexions Web site


Why this should concern you.

The size of the hippocampus decreases with age which often leads to memory decline and decrease in mental efficiency. In many older adults, cognitive deficits are commonly associated with old age. Researchers estimate that by 2050, there will be more than 115 million people that will suffer dementia globally. However, evidence shows that memory decline and aging of the hippocampus can be reduced and ultimately lower chances of dementia by exercising regularly.


Is one form of exercise more beneficial than the other?

As of now, researchers have not yet found an answer. The reason being is that most of the studies conducted only experimented with walking and/or running. However, it is suggested from the studies available that any type of exercise that would be able to elevate the heart rate to a certain level would produce these cognitive benefits.

As someone who enjoys being physically active and mainly weight trains, I was astonished about the benefits of aerobic exercise – all of this was new information to me. Ever since I learned further about these benefits of aerobic exercise, I have incorporated running to achieve a healthier, more cognitively efficient brain.

Figure 2. Man running. Source: Kyle Cassidy

If you are physically able to exercise and do not currently do so, I hope this post encourages you to reach for your pair of runners, go out, and “jog your memory”.

 

It is never too late to start exercising.

– Aron Ha

Brainless slime mold grows in pattern like Tokyo’s subway system

Physarum polycephalum, literally the “many-headed slime”

You may have spotted these yellow slime mold in your backyard, they flourish in shady, moist areas, such as decaying leaves. It is a single-celled organism that is not an animal, plant nor fungus. Scientists classify them to the taxonomic group named Protist, which is a group of organisms that are unicellular or unicellular-colonial and form no tissues. Slime mold isn’t capable of forming tissues, let alone organs or body systems. But surprisingly, a group of scientists from Japan found the brainless slime mold, Physarum polycephalum, to be able to remember, decide and solve complex optimization problems.

A group of researchers led by Toshiyuki Nakagaki from the Hokkaido University in Japan, placed Physarum polycephalum in a petri-dish scattered with oat flakes. The position of food scraps was deliberately placed to replicate the locations of some of the most visited site in Tokyo. In the first few hours, the slime mold’s size grew exponentially, and it branched out through the entire edible map. Within a few days, the size of its branches started to shrink, and the slime mold established a complex branching network between the oats on the petri-dish. Despite growing and expanding without a central coordination system like the brain, the mould had re-created an interconnected network made of slimes that looks almost exactly like the efficient, well-designed Tokyo subway system.

Comparison of the Physarum branching networks with the Tokyo subway networks

As you may know, the Tokyo’s rail system is one of the best in the world. With 102 train lines, it serves an estimated 14 billion passengers per year. Such a legendary metro system is the fruit of collaboration between community dwellings, civil engineering, urban planning over decades. However, the lowly slime mold solve this complex spatial problem in a matter of just a few days.

A beautiful map of the complex Tokyo subway system

Slime mold has been evolving on our planet for an estimation of at least 600 million years, and has survived through countless rounds of evolutionary competition. If we could capture the essence of this ancient adaptive network formation system and summarize it in to engineering and biological models, it will certainly inspire new algorithms that guides network construction many domains.

—-Ran Bi

Eat less, live longer?

Did you know that eating less could extend your life? That sounds impossible, but eating less relates to restricting food intake, which to some extent, could benefit people’s health in preventing age-related diseases. Although there’s still no answer to the secret of a long life, scientists have made great efforts in the past years on studying the effect of calorie restriction on lives of animals and humans.

Monkeys as subjects: 

In the late 1980’s, two studies were conducted on rhesus macaques, human-like primates. One study was done by scientists at the Wisconsin National Primate Research Center(WNPRC).The researchers recruited young rhesus monkeys, aged 7 to 14. In 2009, they published a preliminary study in the journal science. At the age of 27, ordinary rhesus macaques had a hump, and the hair on their faces turned gray. By contrast, the calorie-restricted rhesus macaques, with their brown fur, are still energetic. The monkeys’ ability to resist age-related diseases has also increased by three times, and the incidence of cancer, diabetes, brain shrinkage and cardiovascular disease has dropped significantly. The result implies that calorie-restriction contributes to monkeys’ health and survival. Another study was done by scientists at the National Institute on Aging(NIH). In contrast, the research team reported in 2012 that calorie restriction can’t prolong the life of monkeys.

Humans as subjects:

One study followed a group of people who adopted caloric restriction diets, with men consuming 1400 calories a day and women consuming 1120 calories a day.

“Most of the benefits of caloric restriction in animal experiments are reflected in the human body. Those who started eating in the middle of their lives for eight years maintained a very good cardiovascular system. ” said Luigi Fontana, a biogerontologist at the university of Washington School of Medicine. According to Fontana’s team, calorie restriction can prevent atherosclerosis, and people who stick to calorie-restricted diets are healthier and have better heart elasticity and heart rhythm variability.

In brief, there are many unknowns about the study of calorie restriction. Let us expect scientists’ future discoveries in the effect of calorie restriction on prevention in aged-related diseases in human, somehow contributed to the increase of humans’ life expectancy.

Author: Xinwei Kuang

 

Negative Side Effects of Caffeine

What is the first thing you do to make yourself less tired? In order to stay awake to work or study, most people consume caffeine for mental alertness . Caffeine is not only included in coffee, but also included in tea, coke, chocolates, energy drinks, and other products that we regularly consume in our daily lives. Caffeine works by stimulating the adrenaline production and blocking sleep-inducing chemicals. 

Image credit: Pete

Although caffeine can help people by energizing them instantly, it can also affect people negatively. If more than 300 mg of caffeine consumed in one day, which are approximately three cups of coffee or three to four cans of soda, it may allow people to stay fully awake. However, the most frightening side effect of excessive amount of caffeine is insomnia, which can caused by six or more cups of coffee (approximately 250 mg of caffeine). From insomnia, one’s work performance and quality of life may be affected negatively.

Image credit: Michael Burger

Caffeine can also cause an increase in stress hormones because when a heart beats faster by the consumption of caffeine, it decreases the blood supply to the intestines. Due to the decrease in the blood supply, it may lead to the indigestion.

Can there be any other severe negative effects of caffeine that may have on humans’ health? In 2011, a study by British Journal of Pharmacology stated that caffeine could possibly reduce the chance of fertility in women because caffeine crosses the placenta and reaches the fetus. Also, University of Nevada School of Medicine showed that caffeine can reduce a woman’s fertility rate by about 27%. Therefore, due to immature metabolism of caffeine in fetus, caffeine can build up toxic levels in fetus, which leads to a higher chance of miscarriage and low birth weight of newborn babies.

What can we do to minimize the possible negative consequences from excessive caffeine consumption? Most people unconsciously become addicted to caffeine due to the desire for wide awakeness. Instead of searching for caffeine-containing drinks or food, it is better to get more sleep or consume other essential nutrients that make you less tired. Therefore, your eating or exercise pattern can be modified in the replacement of excess consumption of caffeine.

Author: Victoria Park

How Does Carbon Dioxide Cycle Through the Oceans?

Have you guys ever wondered where carbon dioxide (CO2) molecule goes after you exhale? A lot of carbon dioxide on the Earth, including what we exhale and carbon from our factories or cars, actually ends up in the ocean. Once CO2 molecule is in the ocean, it might travel in through the surface for a while before going back to the air above or it can travel deep down into the ocean and stay there for hundreds of years. A computer model was made to track CO2 in the ocean in order to find out where it travels and the time duration it stays at the bottom of the ocean. Research has shown that carbon dioxide cycles in different levels of the ocean. This information enables us to find out how the ocean responds to and contributes to global climate change.
 
The oceans play an important role to the Earth’s climate change because it can take in a huge amount of carbon above and store carbon in the atmosphere. In fact, more than 93% of the carbon dioxide (CO2) in the world is stored in the oceans. Fortunately, most of the CO2 is stored in the oceans, which leaves less CO2 in the atmosphere. The reason is that Greenhouse gases such as CO2 can trap heat that is radiated back to the Earth, which can overheat our planet. Thus, oceans help to store a large amount of CO2.
YouTube Preview Image
Tiny plants called phytoplankton live on the surface of the water where they can be exposed to sun. They gather CO2 from the atmosphere to build their bodies. When they die, phytoplankton sink into the bottom of the oceans and bacteria break them down to release the stored carbon dioxide back into the seawater. This process is called biological carbon pump, which pumps carbon dioxide into the bottom of the oceans for many years.
 
Study has shown that phytoplankton are usually bigger in colder areas compared to warmer areas and stick together into large clumps when they die. This will make them heavier and sink down into the ocean further and faster before they get decomposed by bacteria. The colder area of the oceans also slows down the bacteria growth, which allows phytoplankton to sink further down before their carbon dioxide be decomposed and released by bacteria.
If humans keep continuing to pollute the Earth and emit CO2 to the atmosphere, the oceans and the world will become warmer. The warm oceans can not store more CO2, which will cause CO2 to be released into the atmosphere and further heat up the Earth. In order to break this cycle, humans need to work together to save our planet and reduce the use of fossil fuels and factory waste into the atmosphere. Also, human beings can avoid many natural disasters such as hurricane, blizzard, and volcanic eruptions resulted from the effect of Global Warming.

The Upside of Stress

If you are a university student or a human being for that matter, you know how it feels to be under an overwhelming amount of stress. Chronic stress, as many may already know, can be detrimental to one’s mental and physical health. Long-term exposure to emotional pressure can lead to elevated blood pressure, heart disease and depression.

Source: Flickr Commons by Emma Brown

Although it would be great if we could be lounging around on a resort far far away from deadlines, exams, and responsibilities, researchers have found that stress at acute levels can actually be beneficial to one’s cognitive function and immune readiness.

Note that chronic stress is referred to as the response to emotional pressure suffered for a prolonged period of time whereas acute stress is stress one suffers for only a short period of time.

Scientists at UC Berkley have put this to the test by using rats as test subjects to see if short-term stress really could lead to a boost in cognitive function. They found that after subjecting the test subjects to acute but short-lived stress, this caused a spike in the rat’s corticosterone levels which also led to the development of new cells in the hippocampus, an area of the brain associated with memory function. The researchers discovered that two weeks after exposure to acute stress, the test subjects performed better on a memory test compared to the test subjects that were not exposed.

Source: Flickr Commons

Source: Wikipedia

Not only is there a correlation between acute stress and memory function, but researchers at Harvard University found that the same hormones released during acute stress can aid to enhance immune readiness during ‘fight or flight’ situations which led the subjects to be more alert as well as be more attuned to possible environmental threats. Some examples of possible triggers for acute stress include preparing for a job interview or being involved in competitive sports, whereas examples of triggers for chronic stress include being in a bad relationship or being stuck in a job that you dislike for a long period of time.

Although acute levels of stress can be beneficial for some individuals, one’s personal experience is a big factor in determining whether a response to stress, even at low levels, can lead to positive or negative effects. For an example, if a person was to have a history of post-traumatic stress disorder, even stress at low levels can trigger a negative response.

The takeaway message is that although too much stress can lead to adverse consequences to one’s health, the right amount of acute stress can improve brain performance. Therefore it is definitely worth figuring out where your own optimal stress level lies.

 

If you are still experiencing stress after reading this post here is another way to make stress your friend.

Source: https://www.youtube.com/watch?v=RcGyVTAoXEU

 

Author: Jasmine Hyun