BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: cortisol

Loneliness Is Bad For The Brain

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On December 2, 2018

In Student Post

This new study from the Thomas Jefferson University in Philadelphia suggests that loneliness can have quite an impact on the brain. The study is based on the effects of social isolation on mice. The mice were raised together where they could play with each other and form social ties. Then they were separated from each other for months on end. The results were quite interesting.

File:Coronal section of a mouse brain stained with Hematoxylin & LFB.jpg

Cross Section of Mouse Brain

After about a month of isolation, the mice developed more “spines” on their dendrites. This is peculiar because this development would usually happen as a response to a positive stimulus. The researchers theorize that the brain is trying to save itself from the loneliness. But this effort is not long lived. After three months of isolation, the brain returns to baseline levels of neural activity. The brain also has reduced amounts of a protein called BDNF, responsible for neural growth. They also found increased amounts of the stress hormone cortisol. Lonely mice also had more broken DNA than their socialite counterparts.

Although it is not known how the results of this study can relate to the brains of humans it may shed some light into the lesser known effects of loneliness on the brain. It also brings into question the effect incarceration could have on a person long term and whether or not it could be more harmful than rehabilitating. What do you think about this study? What could the results of a similar test on humans yield?

Clock Change is Actually Great For Your Brain!

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On December 10, 2017

In Student Post

November this year, our clocks went back an hour, which accelerated the arrival or darker evenings and seemingly “shorter days”. It doesn’t actually make the days any shorter, in merely just shifted an hour of available daylight from the evening to the morning. Most people take lighter evenings as a priority over lighter mornings, arguments are always made over the benefits for easier travel in lighter evenings from clock changes. However, research suggests that holding onto lighter mornings could give more advantages. Having light in the morning, instead of any other time of the day, leads significant brain-boosting results. In fact, it helps us to function much better.

Early Morning

Credit: Attribution license: Porsche Brosseau

Source

All living animals and plants on Earth revolve their lives around the 24-hour cycle of light and dark. For humans, we desire to sleep during the dark night, and our bodies are honed to environmental light via a biological chain reaction. 

We, humans, detect light intensity by special cells in the retina, then the information is relayed to the internal body clock in the brain, called the suprachiasmatic nucleus. It is in the hypothalamus (which uses the endocrine system to regulate internal body processes), which is linked to hormone secretion, through the pituitary gland. These light messages’ job is to internalize information about light intensity in the surrounding environment.

The chain reaction continues with the brain driving the secretion of the hormone cortisol for a specific time of the day, it is in low levels in the dark and high levels in the light. Cortisol is a very important hormone that has very dramatic effects on the human brain and body. The cortisol is also known as the “Stress hormone” that keeps us healthy through its 24-hour pattern.

The cortisol awakening response(CAR) occurs the first 30 minutes of waking up, it is a strong burst in cortisol secretion. The lighter the mornings, the bigger the CAR. Which directly results in a better functioning brain throughout the day. In an experiment, people who have greater seasonal depression, stress, anxiety and lower arousal exhibited the lowest winter CARs. But when they are exposed to artificial light during their awakenings, their CAR was restored. Thus proving that morning light is the most effective treatment for the winter blues.

Other research has also shown that CAR in the morning is directly linked to better brain plasticity, better goal-setting, decision-making and executive function.

The burst of cortisol secretion in the morning sweeps throughout the entire body where it is recognized by receptors on all body cells. The receptors then generate the biological chain reaction to allow us to function better for the day ahead. A lack of light in the morning can make us feel not functioning fully, and an exposure to light in the morning is extremely beneficial.

Source:

https://www.scientificamerican.com/article/why-the-clocks-changing-are-great-for-your-brain/

Bullying and its Epigenetic Effect

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On March 9, 2015

In Student Post

Unfortunately, bullying is commonplace in most schools in America.  Most people are aware of the mental and psychological harm that bullying can cause, but not until very recently have they been aware of the lasting physical changes it can cause.  With the discovery of epigenetics, or the study of genetic traits or expressions that are not caused by DNA, but rather by the methylation or concealing of genes, a new door into the effects of bullying was opened. A group of researches from the UK and Canada performed a study on identical twins.  At age 5, the twins had not been exposed to bullies and expressed almost all of the same traits, physically and emotionally.  The researchers then waited until the twins were 12, imageand revisited only the twins that had different experiences with bullying (one twin was bullied when the other was not).  The researches found big disparities in the twins epigenome, or the way they express their genes.

 

The bullied twin’s protein that codes for a protein that helps move the neurotransmitter serotonin into neurons called SERT had significantly more DNA methylation in its promoter region.  This change is thought to dial down the amount of proteins that can be made from the SERT gene — meaning the more it’s methylated, the more it’s “turned off.”  Therefore, the bullied twin is unable to produce as much serotonin.  This effect is thought to persist through a person’s life.  The effects of bullying will persist an entire lifetime.

 

The researchers also tested how the twins responded to stressful situations differently.  The bullied twin had a much lower cortisol response than the twin that had not experienced bullying.  Cortisol is a hormone that helps people through stressful situations, like being bullied.  However, having too much cortisol is harmful to the body.  The bullied twin’s body turned off the gene that aids in cortisol production because they were being put in stressful situations so often by bullies that their body couldn’t tolerate the amount of cortisol they were producing.

 

This study is not only interesting from a scientific standpoint, but it is also very important in the movement against bullying.  These scientists proved that bullying not only does immense psychological harm, but it also effects people’s well being in a very real and lasting way.

 

 

 

Link to article: http://www.huffingtonpost.com/sharon-moalem/bullyings-terrible-legacy_b_5142857.html

 

Massages Actually Relieve Stress!

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On December 3, 2012

In Student Post

flickr
Photo by FoundryParkInn

When people say that they are taking a spa day, people are skeptical. But, according to a new study massages lower levels of stress hormones in the body. According to this study, people who have regular massages have substantially lower levels of cortisol and higher levels of white blood cells compared to people who do not get massages regularly.

Dr. Mark Hyman Rapaport, the chairman of psychiatry and behavioral neurosciences at Cedars-Sinai Medical Center, said, ” […] the findings are very intriguing and exciting, and I’m a skeptic!”

The study consisted of 53 adults. 29 of these adults were given a 45 minute Swedish massage once or twice a week for 5 weeks. The other 24 adults in the study were given light touch massages for the same time period. After the 5 week trial, the adults who had received the Swedish massages had significantly lower levels of cortisol, significantly higher levels of oxytocin, and slightly higher levels of white blood cells than those who had received the light touch massages.

The Mayo Clinic points out that regular massages can help to alleviate stiffness, pain, anxiety, depression, and maintain a regular blood pressure. The health benefits of massages are endless!

For more information on the health benefits of massages go to: http://stress.about.com/od/stresshealth/a/cortisol.htm

 

Put Down, the Camera, Stop Taking Selfies: The Pitfalls of Being a Narcissistic Male

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On March 18, 2012

In Student Post

Photo Credit: Baking_in_pearls at flickr.com

Do you like to look good? Do you like to look so good that you like to look at yourself in the mirror, like a lot? Well you might be a narcissist. According to a recent study done at University of Michigan, all that time you spend dolling yourself up and obsessing over your appearance can put you at higher risk for cardiovascular problems and high blood pressure, well that is if you are a male. This study “examined the role of participant narcissism and sex on basal cortisol concentrations.”

The Experiment:

Using saliva samples, researchers measured baseline cortisol hormone levels in student participants. Cortisolsignals the level of activation of the body’s key stress response system, the hypothalamic-pituitary-adrenal (HPA) axis. Participants were asked not to do any activities that would trigger the body’s stress response before testing the hormone levels. Elevated levels of cortisol in a stress-free situation would indicate chronic HPA activation, which has significant health implications such as increased risk of cardiovascular problems and high blood pressure. Next, the students filled out a questionnaire, which tested the five components of the narcissism personality trait. According to researchers, “two of these components are more maladaptive, or unhealthy — exploitativeness and entitlement; and the other three are more adaptive, or healthy — leadership/authority, superiority/arrogance, and self-absorption/self-admiration.”

The Results and Findings:

Researcher, Reinhard  says “narcissists have grandiose self-perceptions, they also have fragile views of themselves, and often resort to defensive strategies like aggression when their sense of superiority is threatened. These kinds of coping strategies are linked with increased cardiovascular reactivity to stress and higher blood pressure, so it makes sense that higher levels of maladaptive narcissism would contribute to highly reactive stress response systems and chronically elevated levels of stress.” However, it what was curious about the scientists’ findings was that higher levels of the stress hormone, cortisol, correlated to males that tested positive for negative aspects of narcissism (such as exploitativeness and entitlement), but the link did not exist in females with negative aspects of narcissism. Even more interesting, neither males nor females with the three positive narcissism traits (leadership/authority, superiority/arrogance, and self-absorption/self-admiration) showed no correlation whatsoever to cortisol levels. These results are particularly interesting because it suggests that narcissism influences how people respond to stressful events as well as their everyday routines. For example, the HPA axis may be chronically activated in males with unhealthy narcissism even if there is no actual stressor. This constant stimulation of the hypothalamic-pituitary-adrenal (HPA) axis, or stress response system, could lead to health risks in the cardiovascular system.

 

For More:

http://www.sciencedaily.com/releases/2012/01/120123175659.htm (“Expensive Egos: Narcissism Has a Higher Health Cost for Men”)

 

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0030858 (The Study)

 

http://www.sciencedaily.com/releases/2010/07/100728121329.htm (“Narcissistic Heterosexual Men Target Their Hostility Primarily at Heterosexual Women, the Objects of Their Desires, Study Finds”)

 

http://www.sciencedaily.com/releases/2011/08/110810101630.htm (“Narcissism May Benefit the Young, Researchers Report; But Older Adults? Not So Much”)

 

 

 

 

 

 

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