Category Archives: Neuroscience

Having lived my entire life in the USA, a country that takes pride in their ideology of the “American dream” (which, if we’re being honest, is working AT LEAST a 40 hour work week in hopes of becoming powerful and wealthy…). And furthermore, being born and raised in the big N-Y-C, I’m used to things i.e. restaurants, shopping malls, supermarkets etc. virtually being open 24/7. So, it was a major culture shock to me when I tried to go to a boulangerie one Sunday afternoon to satiate my hunger and to much dismay, found out that it was not open after I walked all the way there. As I enter my 5^th week studying abroad in Paris, this French-styled siesta continues to be a difficult concept for me to wrap my head around.

The French love their time off! Most French people work a 35-hour work week with 5-weeks paid vacation time that is not including their time off for holidays. I’ve noticed many restaurants only open for brunch and again for dinner, and most remain closed on Sundays. Major shopping malls like Galeries Lafayette, BHV, and Printemps aren’t open on Sundays as well. This is so bizarre to me; Sunday, a day where major American cities would grapple at the opportunity to capitalize off of their tourists, is the day the French chose to rest. They seem to not care so much about such trivial things like making a profit. Why? Doesn’t everyone love money? The French would rather their long lunches at the nearest café and their Sundays off to spend time with their families or significant other. After doing some research, I propose that the French place a higher value on social interaction and leisure. Some may call the French lazy, but I say no: the French are simply in love with oxytocin (granted the immense amount of Parisian PDA I’ve witnessed). Oxytocin is a hormone that acts like a neurotransmitter in the brain and is released by the hypothalamus. In humans, oxytocin is thought to be released during hugging, touching, and orgasm in both sexes, it induces a general sense of well-being including calm, improved social interactions, increased trust, and reduced fear (Ishak et al., 2011).

Typical Parisian Cafe, near ACCENT (where I take classes).

A recent study looked at the social buffering hypothesis and the governing effects of oxytocin (Smith and Wang, 2014). The social buffering hypothesis states that social animals are better able to recover from stressful experiences (i.e. the work-place) through positive social interaction (Kikusui et al., 2006). The researchers hypothesized that oxytocin plays a role in the stress response in rodent models. To test this hypothesis, female prairie voles were exposed to 1-hour immobilization stress and then recovered alone or with their male partner to mimic the effect of social contact. They then treated immobilized female voles recovering alone with oxytocin or vehicle and female voles recovering with their male partner with a selective oxytocin receptor antagonist or vehicle. If the researchers did not use the appropriate controls, we would not be able to determine the mediating effects of oxytocin on the stress response. The researchers found that 1 hour immobilization decreased the amount of time female voles recovering alone explored the open arms in an elevated plus maze and increased corticosterone levels in comparison to female voles recovering with their partners and the controls (Figure 1). Intra-paraventricular nucleus oxytocin injections reduced behavioral and corticosterone responses to immobilization, whereas injections of an oxytocin receptor antagonist blocked the effects of the social buffering. The male partner acted as a social buffer which increased oxytocin release in the paraventricular nucleus (PVN) of the hypothalamus in the female. Using an enzyme-linked immunosorbent assay, the researchers found that immobilized female prairie voles that recovered with a male partner had a significantly lower level of oxytocin in the PVN compared with other groups (Figure 3C). By use of microdialysis, the researchers identified increased levels of extracellular oxytocin concentrations (Figure 4B). These data demonstrate that PVN oxytocin release is increased with social interaction.

I chose this paper to propose a reason for the short work weeks many Parisians possess. The French seem to understand the necessity of healthy human interaction when it comes to the everyday stresses of life. Money can make someone happy only for so long, but in the end, it’s the meaningful connections with others that are maintained over these lunch breaks and restful weekends that can aid in lowering stress levels and increasing happiness. Both factors makes for a healthier individual. Hmm, maybe NYC should shut down on Sundays… Ha! Now that’s never going to happen. Just the thought of Times Square without people seems rather ridiculous, better yet scary O_O!

Until next time! Au revoir!

-Danielle

References

Ishak W, Kahloon M, and Fakhry H. (2011) Oxytocin Role in Enhancing Well-being: A Literature Review. Journal of Affective Disorders 130(1-2): 1-9.

Kikusui T., Winslow J. T. , and Mori Y (2006) Social Buffering: Relief from Stress and Anxiety. Philosophical Transactions of the Royal Society Biological Sciences 361(1476): 2215-2228.

Smith A., and Wang Z. (2014) Hypothalamic Oxytocin Mediates Social Buffering of the Stress Response. Biological Psychiatry 76(4): 281-288.

Hi Friends!

There are so many scents in Paris that I can talk about, ranging from lovely floral fragrances to freshly baked baguettes in patisseries. My olfactory (another word for smell) senses are overwhelmed with all the new odors that I’m exposed to! Last week, during a class excursion, we went to the Fragonard Fragrance Museum. We got to tour the museum and learn about the history of fragrance. Apparently back in ancient times, they used fragrance to preserve the dead so that the people could mourn the bodies during ceremonies. It’s bizarre to think how much the usage of fragrance has changed since the beginning of time! Now the perfume industry is all about making yourself appear attractive. When I was at Fragonard, my favorite perfume scents were floral mixed with fruity. It was an exciting experience to find the perfect perfume for myself (and my family) and it was extremely fun to try to distinguish all the different scents. I learned from one of my classes here that the human olfactory system can distinguish more than a trillion olfactory stimuli (Bushdid, 2014). One trillion?! That’s a ton of different smells!

I got these three perfumes at the Fragonard Museum for me and my family! Hopefully we all smell nice 🙂

Even though there are many pleasant scents here, I also found some that are cringe-worthy. For example, I noticed that many Europeans smoke cigarettes and the streets are constantly polluted with people smoking. Cute bistros will have tables outside where people smoke, which makes my dining experience quite unpleasant when I’m eating in a haze of smoke. I guess I am never really exposed to this much smoking in the states, so I spent the first couple of weeks here adjusting to the smell of cigarettes. After thinking about all these pleasant and unpleasant smells, I started to wonder…how does this relate to neuroscience? Surely my field of study can explain how my olfactory senses adjust to unpleasant smells!

Typical tables outside of a French bistro. This is my favorite one called Bistrot d’Edmond!

In a study done by Ferdenzi et al. in 2014, the researchers found that repeated exposure to odors induces “affective habituation” of perception and sniffing. “Affective habituation” was a phenomenon described by Cain and Johnson in 1978 that states repeated exposure to a scent shifts odor pleasantness ratings toward neutrality. In other words, this theory says that we will start to like a pleasant smell less and feel more neutral to it if we are exposed to it repeatedly. Cain and Johnson’s “affective habituation” phenomenon happens with unpleasant smells, too. Previous studies, however, only focused on self-reported ratings and did not investigate variations of physiological responses among individuals. Thus, Ferdenzi et al. aimed to analyze both self-reported ratings and changes in sniffing patterns to pleasant and unpleasant smells.

Ferdenzi et al. first recruited twenty-six young adults at a French university (what a coincidence this study was done in France!). The researchers split these people up into two groups – the “likers” and the “dislikers” when presented with an odor such as chocolate. They kept track of these groups and repeated this step with 8 different odors through a nasal mask. The “olfactometer” was connected to a nasal mask and measured how much each person breathed, which calculated the levels of sniffing. Lastly, study participants were instructed to rank how pleasant each smell was on a computer.

This picture shows the experimental device and how study participants would wear a nasal mask in order to smell the odor and rank its pleasantness.

Ferdenzi et al. found that pleasantness significantly decreased with time in “likers” while unpleasantness tended to decrease with time in “dislikers.” Increase in sniffing also correlated to a shift in greater pleasantness ratings, meaning that people would sniff more when they were repeatedly presented with an unpleasant smell. In general, their findings support the “affective habituation” hypothesis both at the self-reported level and at the olfactomotor level. This is interesting because I find this to be congruent with my life experiences. I notice that I find an unpleasant smell less aversive when I’m repeatedly exposed to it. However, I wonder if 26 young adults is a representative sample of the general population. I wish they had more test subjects and an equal amount of males and females in this study so that the researchers can have a more comprehensive analysis. Previous research has shown that females have better odor identification abilities than males (Doty et al., 1985). I wonder what the results would have been if they had an equal number of males and females.

I now understand why I am becoming more immune to the strong smell of cigarettes here in Paris. Affective habituation and neuroscience can definitely help explain this weird phenomenon! Maybe one day I’ll get accustomed to the pungent smell of body odor on the metro (ha ha!). Let’s just hope that people will wear deodorants on hot days so that I don’t have to deal with smelling and feeling body sweat on the train (eek!). I hope you enjoyed this blog post about smell and neuroscience. Sending love from Paris! 🙂

-Kimi

References

Bushdid C, Magnasco MO, Vosshall LB, Keller A (2014) Humans Can Discriminate More than 1 Trillion Olfactory Stimuli. Science 343: 1370-1372.

Cain WS, Johnson F Jr (1978) Lability of odor pleasantness: influence of mere exposure. Perception 7(4):459-65.

Doty R, Applebaum S, Zusho H, Settle R (1985) Sex differences in odor identification ability: A cross-cultural analysis. Neuropsychologia 23(5)667-672.

Ferdenzi C, Poncelet J, Rouby C, and Bensafi M (2014) Repeated exposure to odors induces affective habituation of perception and sniffing. Front Behav Neurosci 8:119.

It is unreal how fast time flies when you are having a great time! I can not believe that two weeks have already passed of my five week study abroad adventure in Paris. Despite the challenging workload of the courses I am taking, I can tell you that I have enjoyed my time here ever since day one (except for the part of experiencing the “jet lag” phenomenon for the first time). This is because I am surrounded by amazing people and I have been able to site-see some parts of Paris with them. I enjoy visiting new places and experiencing their cultural and aesthetic characteristics. I think that one of the best ways to explore the culture and beauty of France during my short time abroad is by visiting as many historical buildings and galleries as possible.

Within the last two weeks, I was able to visit the following places: Eiffel Towel, Musée du Louvre, Musée de l’Orangerie, Arc du Triumphe, Musée Dupuytren, Musée de l’Histoire de la Médecine, and the Château de Versailles (Yes, the very touristy ones are important too!). I have previously visited some museums and historical sites back home, yet it was until this past Sunday, while walking through the beautiful gardens of the Chateau de Versailles, that I began to ask myself about the neuroscience behind art perception and appreciation.

At the Gardens of Versailles

Exploring the city after class (Left to right: Nicole, Sasha, me, and Danielle). Photo credits: Celia Greenlaw

That same day, after I arrived back to my room in Cité Universitaire, I searched for studies that would help me to understand if the brain perceives aesthetic objects differently. Unfortunately, I was able to find two research articles that are interesting and that provide insights about the biological foundations of art appreciation. So hopefully by the time you complete reading this post, you will understand about the effect(s) of art perception and appreciation in our behavior.

Let me begin by telling you about the study of Brieber et al.( 2014), that tested the effect of context (location) on the experience of art and the time spent viewing the art. In this study, two groups of participants (44 students between the ages of 18 and 31, with normal or corrected vision and no formal training in art/art history) were randomly divided into two groups: the museum group and the laboratory group. These groups represented the context in which the participants viewed an art exhibition: The museum group viewed original artworks in the museum and the laboratory group viewed digital reproductions of the same artworks on a screen in a laboratory. The viewing time of the participants was recorded using a mobile eye-tracking device. In addition, the participants were allowed to freely view the exhibition and were also given a map of the respective exhibition. Finally, after the participants completed the viewing of the exhibition, they were asked to rate each of the artworks found in it on the following criteria: liking, interest, understanding, and ambiguity.

To make things short, after the data were statistically analyzed, the researchers found a significant difference among the participants in the museum group. The participants in this group viewed the artworks for a longer time and that they also rated them higher in both liking and interest, contrary to the laboratory group. Based on these results, the study was concluded with the notion that art museums (the context) help to foster a more focused and enduring experience of art and that such context can also modulate the relationship between the general experience of the action and a particular behavioral response.

Although this study was interesting and presented a way to account for the context of the presentation of art, I think that the data that were obtained are not sufficient to help me understand how seeing the Mona Lisa at the Musée du Louvre is different, in brain activity, than when looking at it on the internet. 

Selfie with the Mona Lisa at Musée du Louvre

Some limitations of the results of this study is that they have the potential to be biased  based on art preferences of the participants. In addition, since the data do not provide convincing evidence of a clear association between context and the perception of art, multiple interpretations and explanations can be derived about the validity of the results. As a neuroscience student, I think that the increase in ratings and satisfaction,  for example, might not simply be due to the context. Maybe the release of the dopamine neurotransmitter in the presence of a novel stimulus is causing the increase in ratings since an increase in dopamine release is associated with the increase of experience of reward, the improvement of perception and action, and an increase in motivation (Krebs et al., 2011).

Personally, I would like to see a follow up experiment of a modified version of this study where not only the context of the visual presentation is taken into account, but also sensory integration or the type of art that is presented. Recording the neural activity of the participants through functional magnetic resonance imaging (fMRI), such as in the study of brain activation during the presentation of paintings and photographic analogs (Mizokami et al., 2014)  could also be used to reduce response bias visualize the regions involved.

So by looking at other articles that studied the role of the brain in art appreciation in more detail, I was able to obtain a more solid understanding about how it that we perceive an appreciate beauty in art through the study by Cattaneo et al. (2014). In this study, twenty volunteer participants (right handed , with normal-to-corrected vision, an average age of 22 and no previous training or special interest in art) were administered a short test prior to the experimental trial to indicate about their preference of representational (with objects) vs. abstract (no objects) paintings. On test day, the participants were seated in front of a 17″ PC screen and asked to perform a computerized trial that consisted of two rating tasks: 1) To indicate, as fast as possible, whether they liked the painting or not by  pressing with their right index finger the left key for “yes” and with the right middle finger the right key for “no”. Immediately after a response, a white screen with a number scale of  “1 2 3 4 5 6 7” was presented at the bottom of the screen. 2) The participants were then asked to use the keyboard to select the number of the scale that corresponded to their appreciation level of the shown image (1= “I do not like it at all”, 7= “I like it very much”).

The stimuli (the paintings) presented consisted of two sets with 36 representational and 36 abstract images. The first set was presented three consecutive times and after a short break, the second set was presented with the order of stimulated sites of the first set trials being reversed. During this time, three 10 Hz transcranial magnetic stimulation (TMS) pulses, which cause the depolarization of cell membranes and initiation of action potentials, were delivered to the left dorsolateral prefrontal cortex (DLPFC) and to the right posterior parietal cortex (PPC) after 100 ms from the presentation of each painting. Fig. 1 of the study (shown below) is helpful to understand these steps.

Picture of where the DLPC and PPC are located

To summarize the findings of this study, the researches of this study concluded that TMS over the fronto-parietal (DLPC and PPC) network significantly affected art appreciation and that its effects depended on the art category and “from the beginning” preference of the participants. These findings are important since some of the areas involved in art appreciation were observed.

Since these two studies helped me to learn that visiting museums has been shown to be more rewarding and meaningful and that some specific brain areas are involved in art appreciation, I will continue to visit as many as I can during the remaining time I have in Paris. From now on, my excuse to go out and explore the city’s historical buildings and galleries will be with the idea of activating my front-parietal network by letting my brain appreciate the beauty of the arts I encounter.

-Maria Vazquez

References:

Cattaneo, Zaira, Carlotta Lega, Chiara Gardelli, Lotfi B. Merabet, Camilo J. Cela-Conde, and Marcos Nadal. “The Role of Prefrontal and Parietal Cortices in Esthetic Appreciation of Representational and Abstract Art: A TMS Study.” NeuroImage 99 (2014): 443-50.

Brieber D, Nadal M, Leder H, Rosenberg R (2014) Art in Time and Space: Context Modulates the Relation between Art Experience and Viewing Time. PLoS ONE 9(6): e99019. doi:10.1371/journal.pone.0099019

Krebs RM, Heipertz D, Schuetze H, Duzel E. Novelty increases the mesolimbic functional connectivity of the substantia nigra/ventral tegmental area (SN/VTA) during reward anticipation: Evidence from high-resolution fMRI. Neuroimage. 2011. Sep 15;58(2):647-55. doi: 10.1016/j.neuroimage.2011.06.038. Epub 2011 Jun 24.PubMed PMID: 21723396.