Seasonal Affective Disorder

Now that it’s time to be studying for finals the weather is finally starting to get nice. It is interesting how much better and happier many people seem now that the sun is out and the weather is warming up and starting to feel like spring. This made me think about how weather and what affects it can have on a person’s mood. Some people believe that sunlight increases the amount of vitamin D, and that this can be beneficial to health and boost a person’s mood. Others think that there is a genetic component to how a person will react to weather. Seasonal Affective disorder (SAD) is the disorder where certain seasons, usually winter, result in depression or lower energy in individuals. This disorder is much more rare down south than it is in northern states where up to 1 in 10 people have been suggested to have the disorder in some form. Interestingly some people experience SAD in summer and feel that the heat and long days makes them uncomfortable and feel “off.”
Some researchers have suggested that SAD could have an evolutionary component. Animals often change their behaviors during the winter seasons as a way to adapt to the seasons hardship. Their metabolism, activity, energy levels can decrease to conserve energy, which may be the original source of what some people experience.
One study looked at the effects on the brain of rats in an experiment that attempted to mimic winter and summer light conditions. They had two rat groups, one that received dim light and dark cycles and the other that received bright light and dark cycles to represent light during the winter and summer. They found that the winter light rat group expressed more depression-like symptoms when tested in water swimming tests and also found that the winter rats had a reduced number of orexinA immunoreactive neurons in their hypothalamus and dorsal raphe nucleus than the summer rats. This suggests that the orexinergic system could have a role in lights regulation of mood.
Interestingly while SAD is more common in northern climates where there are longer winter and colder weather, some of the happiest ranked places in the world are in northern territories. Countries like Sweden and Denmark are far north with long winters yet are supposedly home to some of the happiest people in the world. This seems to go against the idea of weather causing depression yet there could be other factors involved as well.
SAD can be treated with drugs such SSRI’s to treat the depression, but can also be treated with cognitive therapies and even light therapy in which an artificial light can be used to imitate the sun, which has been shown to have a significant positive effect for many people.

References:

Nesse, Randolphe M; Williams, George C (1996). Why We Get Sick (First ed.). New York: Vintage

Deats, S. P., L. Yan, and J. S. Lonstein. “Attenuated Orexinergic Signaling Underlies Depression-like Responses Induced by Daytime Light Deficiency.” National Center for Biotechnology Information. U.S. National Library of Medicine, n.d. Web. 13 May 2014.

Kids Will be Kids

For my CLAS talk I spoke about eugenics and selecting favorable traits for offspring. I was intrigued, then, when i came across an article with the following headline: “Stress Gives You Daughters, Sons Make You Liberal”.  Increasing amounts of literature have revealed a trend wherein sex ratios seem to be greatly affected by stressful environmental stimuli, i.e. natural disasters and political upheavals. Specifically, in situations where the female is at risk rather than the male, the female is more inclined towards the “safer investment”: daughters.  The general theory postulates that this sex selection occurs by signaling within the mother’s body that gets disposes of male blastocysts. The biology behind this natural selection seems to make sense.

However, where is article is truly interesting is in the second half of the title: the idea that our children can affect our own behavior and beliefs. The article has an interesting hypothesis that parents with daughters are more likely to vote republican, while parents of sons tend to vote democratic. This is a rather strong statement, however if you think about it parents tend to be very protective over girls compared to boys. Think about the situation of a parent walking in on their teenage child having sex. The daughter is likely to be locked away, grounded, not allowed to date, go anywhere without supervision, where as the son is more likely to get a stern talking to, a high five from the dad, a “boys will be boys” from his mother. Perhaps these values towards the natural want to protect and shelter, and keep their little girl a “little girl” reflects upon them in other aspects such as voting against radical change and keeping more traditional values. Just as a boys parents want him to go out and “become a man” and make his name in the world they also reflect that in their voting to for a maturing and growing nation. Perhaps as the gap between genders closes in the future we will also see less correlation between gender of children and voting.

There are a few more examples in mind pertaining to mindset of raising certain sexes of children nowadays and in the past. There’s the obvious “if my little girl has a gun, or the death penalty, etc. To protect herself she won’t be raped.” Vs. ” it’s whatever, it’s not like anyone will rape my son anyway” Then there’s ” if the people in our country had more traditional values then maybe they would help my little girl with a flat tire/directions/a safe place instead of making her afraid or ignoring her completely.” Vs “he’s a man, he can handle himself.”

Studies like this open up fascinating new explanations on how we perceive our sociocultural roles. In time, we may very well gain a more complete, sophisticated understanding of what exactly makes humans “tick”.

Link to the article: http://nautil.us/issue/13/symmetry/stress-gives-you-daughters-sons-make-you-liberal

The Effects of Sleep Deprivation

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So as the semester comes to a close, finals looms over the heads of us undergrad college students. What does this mean? Late nights studying and writing papers, with few hours of sleep. But is this really the best thing for us?

Sleep is important for many reasons. Deep sleep helps the connections between cells, and Rapid Eye Movement (REM) sleep is when we consolidate memories. The effects of not enough sleep are obvious: you’re tired, you feel like your brain is cloudy or you are thinking slow, and may even feel grumpy that you don’t have time for a nap. But chronic sleep deprivation can have scary effects. 

Sleep deprivation has been shown to: increase the risk of having a stroke or developing diabetes due to increased insulin resistance, lead to obesity (think: late night munchies) due to an increase in the production of the hunger hormone ghrelin, damage bones because of osteoporosis (in a study, rats that were sleep-deprived showed changes in bone mineral density and bone marrow), increase cancer risk, increase resting blood pressure, hurt your heart (with stress and strain, the body produces more chemicals and hormones that lead to heart disease), and finally sleep deprivation has been linked to earlier age of death.

A recent article posted on Cnn.com also investigated the long-term effects of sleep deprivation, particularly in shift workers who may not get the full eight hours of sleep needed in a night. The article states that it may be a myth that you can pay back sleep debt, because brain damage may have already occurred. In a study at University of Pennsylvania, mice were allowed to sleep and then awakened at either short or long intervals. The mice’s brains were then examined. The scientists found damage at the locus coeruleus, a bundle of nerve cells associated with cognitive function and alertness. In fact, the mice lost 25% of these neurons. The scientists believed that when the mice lost a little sleep, the nerve cells reacted by making more protein to protect them. But with chronic reduction in sleep, the reaction shuts down, and the cells begin to die off.

So, when students stay up all night studying, his or her performance may be worse on a final exam, because the information he or she is trying to learn does not have the chance to consolidate. But the scarier thing is what impact these sleep-deprived nights may have on the student’s future.

 

Works Cited:

http://psychcentral.com/blog/archives/2013/02/13/8-effects-of-sleep-deprivation-on-your-health/

http://www.cnn.com/2014/03/19/health/sleep-loss-brain-damage/index.html?hpt=hp_t2

http://www.huffingtonpost.com/2013/03/06/scary-sleep-deprivation-effects_n_2807026.html

What’s That Smell?

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Men and women are different. So different, in fact, that it might be ruining all experimental research.

 Beyond the more obvious physical traits, sex differences are also displayed in our approaches to problem-solving as well as in the presentation of various illnesses. While on a tangent in class, we discussed how research indicates antidepressants affect women more strongly for their body weight than it affects men. This took a long time for researchers to discover because most medical testing is done on males because the periodic changes in the female body can obfuscate experimental results. It was assumed that men and women would react to medications the same way, so all male results could be generalized to women. But this logical fallacy is just the tip of the iceberg. What if the researcher’s gender matters too?

Jeffrey Mogil is a pain researcher at McGill University in Montreal. During the course of their research, Mogil’s team noticed that rodents tended to lick injection sites, a sign of pain, when humans were nearby. When the team delved deeper, their results were astounding: the rodents were licking their wounds less in front of the male researchers, but not the female researchers. The team theorizes that the scent of a lone male usually indicates danger, so it was evolutionarily beneficial to not display pain or weakness. In fact, further research demonstrated that the animals weren’t just hiding their pain; the male researchers’ scents wer actually working as a painkiller.

The ramifications of this research are astounding. If the scent of the researcher is a confounding factor in pain research, it could have effects in other fields of medicine. Between test subject gender and researcher gender, this recent research could call into question the results of many previous experiments. Mogil doubts that these new findings invalidate the findings of previous researchers, but he does agree that gender is a factor that should never be ignored, even when it doesn’t seem obviously important.

 

References

Grimm, D. (2014, April 28). Male Scent May Compromise Biomedical Research. Retrieved from Science Magazine: http://news.science.org/brain-behavior/2014/04/male-scent-may-compromise-biomedical-research

I Remember Everything

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Well, It’s certainly possible. Hyperthymestic syndrome stems from the Greek word thymesis which stands for remembering. Up to date, there are approximately 25 known cases of hyperthymestic syndrome, the ability to recall one’s personal past on any given day from a very early age. AJ, is the first known individual to possess hyperthymestic syndrome can remember everyday of her life from the age of fourteen. But just how does this work?  A analyzation of such cases were done via fMRI and found that a neural network including the left-lateralized regions, more specifically, the medial and ventrolateral prefrontal, medial and lateral temporal and retrosplenial/posterior cingulate cortices, the temporoparietal junction and the cerebellum, were activated and taken into consideration.  For the case of AJ, both the temporal lobe and the caudate nucleus were found to be enlarged. The hippocampus, located in the medial temporal lobe is responsible for short term and longer term memory, as well as spatial memory. The hippocampus is also a part of the limbic system, otherwise known as the region responsible for our emotion, including arousal, fear, aggression, happiness, and anger.  Something interesting to think about is the theory that we tend to remember events that are emotionally salient. It can be assumed that perhaps the neural processes involved in that process, for those with hyperthymesia, are being wired and connected differently. The caudate nucleus is also known for its role in memory and learning, so and increase in size might give light as to how individuals like AJ come to possess this automatic accurate memory for autobiographical events. Psychologically, researcher posit that both semantic (basic knowledge for familiar people, objects, locations) and episodic (memories for events) memory processes overlap and work together to allow the individual to remember details vividly and accurately.

So, what if you could remember everything? It seems like syndrome that at first glance, many would envy. However, if you really thought about it, imagine how haunting this would could be? AJ described it as “ruling her life…and a burden.” Claiming that whenever she thinks of one thing, her mind races to another and so and so forth. Remembering everything you learned from the first two years of medical school would be nice, but remembering all your bad days and your worst thoughts just might not be worth it. Our ability to forget, we often forget, should be considered a blessing in disguise.

Svobodaa, E., McKinnona, M., and Levine B. (2006) The functional neuroanatomy of autobiographical memory:A meta-analysis. Journal of Neuropsychologia, 44, 2189-2208.

Parker E., Cahill, L., and McGaugh, J. (2006) A case of unusual autobiographical remembering. Journal of Neuroscase, 12, 35-49. 

What a Girl Wants: Strategic Moves on the Dance Floor

In the last few classes of my Animal Behavior class, we have switched from more “typical” animal behavior discussions to discussions about human behavior and its causes. Being interested in psychology/neuroscience, I have been absolutely fascinated with this part of the class. Yesterday, we discussed Evolutionary Psychology and the possibility of sexual selection in humans.

In our talk about sexual selection, we discussed a study that investigated which dance moves are more likely to catch a female’s eye on the dance floor. How was this done? Thirty male participants were filmed while dancing, and avatars were created from their movements. Then, thirty-seven women rated the attractiveness of each avatar’s dance moves. What was found? Variability and amplitude of movements in the head, neck, and torso and speed of right knee movements are indicative of good/attractive male dancers. This means lots of bending and twisting of the torso, bobbing of the neck, and raising of the right knee (watch the videos below for examples!).

Good dancing, bad dancing

So, why are these dance moves more appealing?! What about raising and moving your right knee with speed is indicative of your attractiveness?! That is where the evolutionary part of evolutionary psychology or biology comes in. It is hypothesized that these moves are more attractive because they are telling of a male’s fitness. The more moves that a male can perform, with more strength and energy, the better adapted he is to his environment. This hints at the idea that he would be able to successfully care for offspring and that his good genes would be passed on to his offspring. In the authors’ own words, a male’s dance moves are “honest signals of traits such as health, fitness, genetic quality, and developmental history” (Neave et al., 2010). Females preferred these dance moves because, at the most basic level, they showed that the male was in shape and fit.

Evolutionary psychology/biology is an absolutely fascinating topic that studies why we think they way we do, based on our ancestor’s needs millions of years ago. How cool!

The article for this study is called Male dance moves that catch a woman’s eye and was conducted by Nick Neave, Kistofor McCarty, Jeanette Freynik, Nicholas Caplan, Johannes Hönekopp, and Bernhard Fink and was published by Biology Letters in August 2010. A link to it can be found here.

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