Tag Archives: biology

Negative effects on the brain caused by recreational marijuana

Marijuana is one of the three main forms of cannabis (a kind of drug affecting mental activity, behaviour, or perception). It is made from the cannabis plants’ leaves and dried flowers.

cannabis / image from Quick GuideUnderstanding Medical Marijuana

 In all the products of cannabis, marijuana is the least powerful. It is always smoked or even made into eatable products such as marijuana ice cream.

marijuana ice cream /image from Dr Greenlove

Therefore, some teenagers think that the marijuana can not hurt them and some of them even think that using marijuana allows them to be relaxed and settle down and improve their concentration. However, the fact is that recreational marijuana-use by youth can cause negative effects on the brain and daily performance.




The Risky Chemical in Marijuana

The delta-9-tetrahydro-cannabinol (THC), a main chemical in marijuana, is risky for biological systems in the brain.

The chemical formula of THC/ image from Evidence for God from Science

THC affects the cerebellum and the basal ganglia. The cerebellum is the area of the brain which controls balance and coordination. The basal ganglia are the parts of the brain which are helpful for controlling movement. These effects impact performance in some activities, such as sports and driving.

THC and the brain/ image from Collegiate Times

So the THC in marijuana can influences on the cerebellum and the basal ganglia in the brain. Even though THC can affect our brain, the bad thing is that THC percentage in marijuana experienced a dramatical increase from early 1990’s to 2013, which is from 3.73% t0 10%.


The Influence on Memory

In teens, the part of the brain for emotion is developed well, while the part of the brain for judgment still not mature. Smith with other researches found in 2001 that in people who use marijuana everyday for about three years, the hippocampus (a region in brain, is related to long-term memory) looked strange.

image from SlidePlayer

The greater differences in shape of the hippocampus, the poorer performance on memory assessment. In a  long-term memory test,  young adults who have never used marijuana scored 18% better compared to heavy marijuana-use youths. So if young people use marijuana, their memory would be affected negatively because of the brain chemistry and brain structure impairment.

In conclusion, recreational marijuana is harmful to the brain if youth uses it, especially when marijuana-use is high potency and long-term.

image from Depositphotos

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