Category Archives: Neuroscience

Difficulties learning a new language? C’est la vie (That is life)

Posted on June 8, 2015 by | 8 comments

Dear friends,

It’s been a crazy couple of weeks filled with excitement and anxiety so I’m sorry for not keeping in touch. Not only is it my first time in France, but it is also my first time ever outside of the States! Expecting a huge culture shock upon my arrival, I was surprised when I realized that this would not be the case.

Au contraire, my immersion into the French culture and language has been relatively smooth. While I cannot say that French has become “très bien,” I did pick up some simple greetings. However, it does not help that most of the friends that I’ve made here also speak Dutch, so I probably learned more Dutch than French.

I made a couple Belgian friends who have been kindly teaching me French (actually Dutch).

I made a couple Belgian friends who have been kindly teaching me French Dutch.

Just the other day, we attended the Belgium vs. France soccer game. While it was such a great experience, I had no idea what was going on half of the time because I couldn’t understand the language! Fans screamed “Allez les Bleus!” or “Waar is da feestj?” while I confusedly looked around until joined in on the indistinct chanting.

Dressing up for the festivities!

On our way to the stadium via RER B!

I knew picking up a new language would be difficult, but I thought that it would be a bit easier than it truly is because of the complete immersion factor.

Map of Stade de France

Map of Stade de France

Despite my constant pestering and asking of “what are they saying” or “how do I say this in French, I find it difficult to remember words or even make the correct sounds. For example, “Stade de France,” or the French Stadium,” is pronounced “stad du frans,” but I find myself struggling to make the “du” sound; I have to actively think about the pronunciation of each word and constantly break down each syllable to even hope that I say anything correctly.

Opening ceremony for the friendly game between Belgium and France

Opening ceremony for the friendly game between Belgium and France

Not surprisingly, the scientific literature behind my need to consciously think about what to say and my failure to quickly become proficient in this second language continuously grows. A recent study even found that specific areas of the brain activate in direct correlation to the amount of fluency in a second language (Shimada et al., 2015)! This study comprised of thirty Japanese-speaking adults with varying levels of spoken English proficiency. The researchers evaluated each individual’s proficiency level using the Versant English test, a short examination on language production and comprehension. The test contained simple tasks such as reading a sentence out loud or listening to a short story. During this examination, the participants laid inside an fMRI machine to determine their brain activation through measurements of blood flow.

Shimada et al. discovered that with higher fluency in this second language, activation of the left dorsal inferior frontal gyrus (dIFG) decreased and activation of the left posterior superior temporal gyrus (pSTF) increased. They also concluded that the decreased dIFG activity reflected the decreased need to consciously think about how to create grammatically correct sentences, and the increased pSTF activity reflected the increased ability to quickly process and understand spoken words. (If you got lost reading the extremely long names of those brain structures, I labeled the dIFG red and the pSTF orange!)

Dorsal inferior frontal gyrus (red) and posterior superior temporal gyrus (orange)

Dorsal inferior frontal gyrus (red) and posterior superior temporal gyrus (orange)

With this information, I am now wondering if it might be possible to induce those activation patterns in my brain to quickly become proficient in French! Maybe I should suggest this idea to the researchers for their next experiment! However, I feel as though I might be too scared to be a participant in such a novel study. Therefore, I am content with my traditional, but painstakingly slow, approach to learning French… for now.

Au revoir!
Phi

(P.S. I still cannot pronounce “au revoir” correctly…)

 

References

Shimada K, Hirotani M, Yokokawa H, Yoshida H, Makita K, Yamazaki-Murase
M, Tanabe HC, Sadato N (2015) Fluency-dependent cortical activation associated with speech production and comprehension in second language learners. Neuroscience.

8 Comments

Posted in Communication, Neuroscience

Tagged , , ,

An Ambulance in a Traffic Jam

Posted on June 8, 2015 by | 1 comment

I’ve often wondered if any good could possibly come from a city full of the constant hustle of urban life. Cars always seem to be coming and going, zipping by on the streets below my window. Then the ambulance speeds past, its siren wailing, as it seeks the nearby hospital. Suddenly I am thrust into memory from last week.

The Bastille

Cars honk to one another as if speaking their own language. Smaller and more agile mopeds cut between them acting like they own the road. Firemen have positioned themselves along the sidewalk and are passing out fliers to anyone who will listen. The wail of a siren stuck in traffic was the centerpiece of a small Parisian intersection near the Bastille. My friends and I paused for a moment, mesmerized by the sounds, lights, and the notion that an ambulance with siren wailing could possibly be halted on its life-saving journey. Our stomachs growl in contempt of our delay so we continue shuffling along the sidewalk seeking nourishment after the morning’s academics, the smell of the boulangeries wafting invitingly towards us.

A delicious looking piece of artwork

The cool breeze from the window brings me back to present. I now wonder how it is that I could remember that instant so clearly, yet there is nothing to say of its significance. As far as I could tell, there was no reason for this memory to be so strong.

The answer lies in the recent work of James Cousins and his colleagues (2014) regarding cued memory reactivation during slow-wave sleep. In his experiment, Cousins subjected his participants to a specific cognitive task and simultaneously played a series of tones. The researchers then put the participants to sleep while monitoring their brain activity. During slow-wave sleep, some of the participants were played the series of tones from the test, while others listened to brown noise (notably different than the “brown note”). Participants were woken up in the morning, allowed to gather their senses, and then retested on the cognitive task.

Sleepy-time cap

Cousins and his colleagues discovered that while the control participants who listened to brown noise all night slightly improved after having learned the task, the participants who were played the tone series improved significantly more. The researchers concluded that, during slow-wave sleep, auditory stimulation enhances the consolidation of related memories by the hippocampus.

Now lets get back to my ambulance example. After experiencing the piercing cry of the ambulance stuck in traffic on that small back road, my brain had begun creating a memory of this experience. That night as I drifted into slow-wave sleep, the sirens from the ambulances on the street below wailed past, causing my hippocampus to replay that particular memory. Over the course of the night, unbeknownst to me, this seemingly irrelevant memory became a recurrent experience.

The Bastille on a map of Paris

I can no longer remember what I did end up eating for lunch that day, nor what we discussed in class. But thanks to my hippocampus and the sleepless city, I will long remember that ambulance stuck in traffic on a sunny morning in downtown Paris.

-Kamin Bouguyon

References:

Cousins, J.N., El-Deredy, W., Parkes, L.M., Hennies, N. & Lewis, P.A. (2014) Cued Memory Reactivation during Slow-Wave Sleep Promotes Explicit Knowledge of a Motor Sequence. The Journal of Neuroscience, 34, 15870-15876.

1 Comment

Posted in Neuroscience

Tagged , , , ,

Mirror, Mirror on the Wall, Where is the Bestest Dessert of Them All?

Posted on June 8, 2015 by | 4 comments

Whenever I travel to somewhere new, I always love exploring their authentic cuisine first. Of course, when I told my friends and family that I was going to Paris for study abroad, everyone told me about all the delicious food the French have to offer. Baguettes, éclairs, escargot, et cetera…you name them. Thus, two weeks ago when I arrived in Paris for the first time, I began my hunt for the perfect dessert!

The hunger (and thirst) has been real. Every corner lies a cute patisserie filled with glass cases of tempting desserts. Where do I even begin?! During the first week of the program, our class went on an excursion to Pere-Lachaise cemetery, a beautiful (though slightly haunting) place where many famous people like Oscar Wilde and Chopin are buried. Our instructors led a group scavenger hunt and the prize was a box of French macarons! This was the perfect opportunity for me to try my first macaron in Paris! Being the competitive person that I am, I hurriedly found most of the tombstones on the list with my team while the clock was ticking.

Here is a picture of the winning team snacking on a yummy macaron!

Here is a picture of the winning team snacking on a yummy macaron!

Little did I know the stress induced by this race had led me craving for sweets. This made me wonder – why do I always crave chocolate and sweets whenever I’m stressed? So then I decided to do some research and found some neuroscience to explain this occurrence.

In a study done by Macedo and Diez-Garcia in 2014, they found that excessively ingesting sweet substances may decrease the effects of stress in women and impact leptin levels. You might ask – what is leptin and why does it matter? Well, leptin is a hormone that regulates your appetite and controls energy by restoring it to normal levels in the body called homeostasis. At these normal levels, leptin promotes a feeling of reward by acting on the mesolimbic dopaminergic system. The mesolimbic dopaminergic system is a reward system in our brain and is activated when we do things that are pleasurable, such as eating or even abusing drugs.

Source: http://highered.mheducation.com/sites/dl/free/0072562463/91056/fig1606.jpg

Here is a diagram of the mesolimbic dopamine “reward” system.

Anyway, leptin levels rise after you eat and stimulate anorexigen neurons, which suppress the appetite. Basically leptin helps you feel full so that you don’t overeat. It has been found that leptin decreases the feeling of reward in the overweight.

The researchers wanted to study how sweet cravings (SC) in women are related to stress and how SC affect leptin levels in the body. They performed this study in 57 women and divided the participants in two groups – “stress-free” and the “stressed.” These women took a survey that asked them if they had a strong desire to eat sweet food over the last three months in order to identify them as a SC participant. The women then had their blood drawn to measure hormone levels and the researchers measured their body composition.

After controlling for a multitude of factors, they found that among the stressed women, 77.42% had SC. They also found that SC women had significantly higher leptin levels. One way to explain this might be because leptin acts on the hypothalamus (area in the brain in charge of hormones) and suppresses the response to sweet food, changing people’s sensitivity to sweet foods (Niki et al., 2010). Therefore Macedo and Diez-Garcia concluded that stressed women are more prone to SC and this condition is associated with increased levels of leptin.

This study has helped me understand why I keep craving for sweets in Paris. After all, coming to a whole new country has been an overwhelming experience, especially since I have to balance schoolwork and explore the beautiful city at the same time. Five weeks is a lot shorter than I anticipated and I want to travel all over Paris but alas, this is a study abroad program so there is work to do! Now I understand how stress has affected my appetite.

Even at the local Monoprix (the French version of Target), I found myself strolling down the aisles of chocolate and buying a couple bars to snack on later. Back home, I never really buy chocolate because it has never been a habit of mine. A scientific review done by Sinha and Jastreboff (2013) claim that acute stress can increase food intake, especially when highly palatable, calorie-dense foods are available. This helps explain why I keep craving for high-calorie sweet things here! Another study researched on the psychoactive effects of chocolate and desire for more chocolate. They found that the sugar and cocoa contents of chocolate are primarily related to the desire to consume more of it (Nasser et al., 2011). This may explain why I usually eat more chocolate if it’s dark than when it’s just white chocolate. Who knew you could tie in food and neuroscience in Paris?!

Before I go, I wanted to finish this blog post with a few pictures of the delicious desserts I have found and also a map of where I’ve traveled.

Other delicious desserts in glass cases all over Paris – they are always so colorful and pretty!

Delicious desserts in glass cases all over Paris – they are always so colorful and pretty!

Éclair heaven in a patisserie near the Accent center where I go for classes every day! My personal favorite is the Speculoos éclair – om nom nom!

Éclair heaven in a patisserie near the Accent center where I go for classes every day. My personal favorite is the Speculoos éclair – om nom nom!

Lastly, a map of all the places I’ve visited for desserts in Paris. Hopefully by the end of this trip, I’ll have red pins all over!

Lastly, a map of all the places I’ve visited for desserts in Paris. Hopefully by the end of this trip, I’ll have red pins all over!

My journey for yummy desserts does not end here! I shall keep you updated on what and where I eat. Bon appetit, readers 🙂

-Kimi Chan

References:

Macedo D, Diez-Garcia R (2014). Sweet craving and ghrelin and leptin levels in women during stress. Appetite. 80:264-270.

Nasser J, Bradley L, Leitzsch J, Chohan O, Fasulo K, Haller J, Jeger K, Szulanczyk B, Del Parigi A (2011). Psychoactive effects of tasting chocolate and desire for more chocolate. Physiology and Behavior. 104(1): 117-121.

Niki M, Jyotaki M, Yoshida R, Ninomiya Y (2010). Reciprocal modulation of sweet taste by leptin and endocannabinoids. Results and Problems in Cell Differentiation. 52: 101-114.

Sinha R, Jastreboff A (2013). Stress as a common risk factor for obesity and addiction. Biological Psychiatry. 73(9): 827-835.

 

4 Comments

Posted in Neuroscience

A Midsummer Night’s Dream in Paris

Posted on June 8, 2015 by | 12 comments

This Saturday marks my 23rd week in Paris. As I get more acquainted with and orientated in this beautiful city full of history and modernity, I feel increasingly happy with my decision to study abroad here.

I lived with a home stay in the 8th arrondissement for 5 months before moving to the Cité Universitaire for these last 5 weeks. [image source: Google Maps]

Delving fully into the language and culture, I’ve had the opportunity to see the polar opposite sides of a resident filled Paris in January to the overwhelming influx of tourists starting early April. Despite the heat of an underground metro without air-conditioning and the invasion of foreigners in a city I now claim as my own, I find myself more in love and happier with my Parisian experience every day as I near my final weeks here.

Lately, I’ve noticed the city stays light long past dinnertime so I take the scenic route home while I usually head straight back to my room to start my work.   However, am I really succumbing to the City of Love . . . or is the lingering sun really the cause of my increased feelings of happiness and simultaneous difficulty in focusing on my work? At a latitude of 48.8457°N, Paris currently experiences days that last over 16 hours (Sun and Moon, 2015). Due to such a northern latitude, we get 2 more hours of daylight to explore the city here in Paris than the 14-hour days Emory University receives in Atlanta, GA.

Sunset at the base of the Eiffel Tower at 9:35pm on May 26th, 2015

Sunset at the base of the Eiffel Tower at 9:35pm on May 26th, 2015

Light on Happiness

The circadian rhythm follows a 24-hour clock that changes our biological, mental, and behavioral processes in response to light and dark (Jackson, 2014). Light, a main natural cue we receive from our environment, regulates these rhythms and is affected by changes in daylight from one season to the next. While little research has been published showing that sunlight will actually make you happier, many studies have been conducted on the topic of light significantly easing depression. A current study aims to artificially mimic the effects of daylight through the use of light therapy for clinically depressed patients suffering from seasonal affective disorder (SAD), where symptoms of depression manifest particularly during winter months when there is a marked decrease in available sunlight (Reeves et al., 2012). Participants received 1 hour of bright light therapy and 1 hour of placebo (a dim red light used as a phony treatment and expected to have no clinical affect) in a randomized order. Using two different self-reporting depression scales, the Profile of Mood States-Depression-Dejection subscale and the Beck Depression Inventory II, Reeves et al. measured patients’ depressed mood before the start of the experiment, after hour 1 of treatment, and after hour 2 of treatment. Researchers found a statistically significant decrease in self-rated depression scores after treatment from before starting the light therapy.  Multiple neurotransmitters, molecular compounds that neurons release in order to communicate with other neurons, are responsible for this rapid mood change. Upon light therapy stimulation, serotonin (a main neurotransmitter responsible for mood balance and involved in seasonal depression) was found to rise at a rate directly correlated to the amount of light administered (Reeves et al., 2012). Our long summer days in Paris allow for natural sessions of light therapy, which in turn leads to happier people.

Light on Attention

So now that I know why I feel happier, I also wondered if these lengthened spring nights in Paris could be having a reverse effect on my ability to concentrate on tasks rather than blaming my lack of motivation on an increasing infatuation with the “City of Love.” As we approach the longest day of the year during the summer solstice on June 21st, the day will be 7 hours and 56 minutes longer than it was when I arrived in the middle of winter (Sun and Moon, 2015). Not only am I staying outdoors longer, I’m going to bed 2-3 hours later than during the spring semester, while still waking up at the same hour as I did in winter. As the days lengthen and we stay more active, the potential for sleep deprivation and associated negative impacts on the brain’s ability to perform increase. Further, certain individuals can be more vulnerable to sleep deprivation, amplifying the resulting impact on performance and sleepiness (Chua et al., 2014). So, as we approach June 21st, I am reminded of the erratic behavior of the young lovers and comedic actors I saw in Shakespeare’s Midsummer Night’s Dream at La Comédie Française this April. Perhaps it wasn’t the meddlesome fairies after all, but rather neuroscience that would suggest they were vulnerable to sleep deprivation caused by the long summer day!

Le songe d’une nuit d’été à la Comédie Française/ Production of Shakespeare’s Midsummer Night’s Dream at the Comédie Française

Le songe d’une nuit d’été à la Comédie Française/ Production of Shakespeare’s Midsummer Night’s Dream at the Comédie Française

~ Amy Yeh

References

Chua EC-P, Yeo S-C, Lee IT-G, Tan L-C, Lau P, Cai S, Zhang X, Puvanendran K, Gooley J (2014) Sustained Attention Performance during Sleep Deprivation Associates with Instability in Behavior and Physiologic Measures at Baseline. Sleep 37(1): 27-39.

Jackson C, Capozzi M, Dai H, McMahon DG (2014) Circadian Perinatal Photoperiod Has Enduring Effects on Retinal Dopamine and Visual Function. The Journal of Neuroscience 34(13): 4627-4633.

Reeves G, Nijjar GV, Langenberg P, Johnson MA, Khabazghazvini B, Sleemi A, Vaswani D, Lapidus M, Manalai P, Tariq M, Acharya M, Cabassa J, Snitker S, Postolache TT (2012) Improvement in Depression Scores After 1 Hour of Light Therapy Treatment in Patients With Seasonal Affective Disorder. Journal of Nervous & Mental Disease 200 (1): 51–55.

Sun and Moon. (2015, May 1). In Time and Date. Retrieved from http://www.timeanddate.com/astronomy/france/paris

12 Comments

Posted in Neuroscience

Tagged , , , , , , , , , ,

An All-Natural High: Running through Paris

Posted on June 8, 2015 by | 1 comment

Bonjour tout le monde!

As my second week in Paris comes to a close, I can’t help but reflect on my time in Paris thus far. Have I accomplished what I’ve wanted to accomplish? Have I met my goals?

One major goal that I set out to fulfill during my time in Paris was to keep running. But before I delve into that, let me give you a little background on my relationship with running.

I never used to enjoy running. In fact, I strongly disliked running. My parents have always been big runners and have run marathons, done triathlons, Tough Mudder-type events, and many others. I could never understand why they would put themselves through the grueling process of burning up your lungs and muscles until you just couldn’t do it anymore. Why subject your body to that much pain? All throughout middle school and high school, the only running I did was on the soccer field or on the volleyball court. But that all changed this past semester.

I can’t tell you for sure what it was that changed my mind about running. To be honest, I think it might’ve been that I wanted to get in shape and I knew running would get me there. So I started running. Every other day, every few days… whenever I found time in my busy Emory schedule to run, I ran. And it got easier each time. I didn’t feel as fatigued when I ran, and the thought of running didn’t incur feelings of immense hatred anymore. I actually started to enjoy it… even look forward to it! You’re now reading the blog post of a girl who is signed up to run a half marathon in the fall, and I couldn’t be more excited about training for it.

While I haven’t had much time to run in Paris between classes, excursions, and exploring, I’ve tried to fit it into my schedule as much as I can, even if it’s  just a short, 2 mile run. The first time I went for a run in Paris, I immediately felt better and had an immediate rush of familiar excitement. As I set off to run in one of my favorite places in Paris, the Touileries garden, pounding along to the beat of “‘Till I Collapse” by Eminem, I finally identified the feeling. It was an all-natural, all-encompassing high.

IMG_0145

Beginning my run in the Touileries (photographed by Joy Lee)

As I entered the park and continued along the path, feeling great, I wondered what caused this high, and how it affected my running performance.

So I came back to my room later that day and did a little bit of research. I found a study from 2008 that described the phenomenon I was experiencing, called “the runner’s high”. This study by Boecker et al. (2008) looked at ten athletes at two time intervals: one after 2 hours of endurance running and one during a rest period. The researchers looked at whether particular opioid receptors (molecules of tissue that bind substances called endorphins that give us a boost when we run) get depleted when we run long distances, and they indeed found that certain areas of the brain do in fact have reduced opioid receptor availability in subjects during endurance running as compared to when subjects were resting!

Screen Shot 2015-06-07 at 7.26.04 PM

Reduction in opioid receptor availability in certain areas of the brain after long distance running compared to when resting

So basically, when we run long distances, we do in fact feel an all-natural “high”, in addition to having pain-relieving symptoms — even though it often feels like we’re about to die when we’ve run for too long (Boecker et al., 2008).

This analgesic effect got me thinking though: what about when we’re extremely fatigued? We don’t seem to feel this pain-killing effect anymore: in fact, the pain is almost unbearable when we feel like we’ve reached our limit. The concept of limits reminded me of a Radiolab podcast that I had listened to while taking Human Physiology with Dr. Cafferty, fall semester 2014. In the beginning of the podcast, Jad Abumrad and Robert Krulwich (the hosts of Radiolab) introduce Julie Moss, who discusses her first Ironman experience. If you watch her running toward the finish line on YouTube, you can see how the fatigue after swimming 2.4 miles, biking 112 miles, and finally a marathon (26.2 miles) truly catches up to her.

https://www.youtube.com/watch?v=VbWsQMabczM

Krulwich and Abumrad then go on to introduce what is known as the central governor theory, along with the help of physiologist Dr. David Jones. This theory describes how fatigue may in fact not be a result of muscles running out of energy: in fact, it may be more mental than we think. When we’re running low on energy, this central governor signals triggers of pain to try to get us to rest. Scientists are finding that this governor circuit is conservative, keeping a reservoir of energy readily available in case of an emergency. While some scientists argue that fatigue is one of the greatest imperfections of the body, Noakes (2012) references an Italian physiologist A. Mosso who says that fatigue may in fact be one of of our most marvelous perfections. As Krulwich jokes in the Radiolab podcast, perhaps fatigue is our body’s “almost out of gas” message, telling us we’re running out of energy when we still have a 1/4 of a tank left.

As I continue to train and eventually complete the half marathon in the fall, I know I’ll be thinking about my central governor and hoping for that endorphin boost; especially as I (hopefully) run toward that finish line, trying to avoid pulling a Julie Moss, running to the melody of Chariots of Fire.

IMG_0162

Selfie of me while running in Montsouris park!

Until next time,

Meg

References:

Abumrad J, Krulwich R. Limits of the Body. RadioLab. http://www.radiolab.org/story/91710-limits-of-the-body/

Boecker H, Sprenger T, Spilker, M, Henriksen G, Koppenhoefer M, Wagner, KJ, Valet M, Berthele A, Tolle T (2008). The Runner’s High: Opioidergic Mechanisms in the Human Brain. Cerebral Cortex 18: 2523-2531.

Noakes T (2012). Fatigue is a Brain-Derived Emotion that Regulates the Exercise Behavior to Ensure the Protection of Whole Body Homeostasis. Front Physiol. 3:82.

1 Comment

Posted in Neuroscience

Tagged , , , , , ,

“Hello” or “Bonjour” ?

Posted on June 7, 2015 by | 3 comments

Hello world,

This past week has been extremely interesting, yet exciting, to say the least. After a TERRIBLE delay at JFK airport, I finally made it to Paris (about 6 hours behind schedule…). Once settled into my room, I met up with my friend, Sasha, to grab a quick dinner. We decided to go to a small restaurant close to where we live, as our long day of traveling left us extremely tired. When we sat down at the restaurant, the waiter walked over and said, “Bonjour, comment puis-je vous aider?” This caught me extremely off guard, as this was the first time I engaged in a conversation with a true francophone.

IMG_1115

Sasha (left) and me (right) at dinner

11234833_10206791179517847_2623424007455916451_o

Sasha and me at the Eiffel Tower

 

Let me rewind a little bit. I have studied French since 6th grade, and although it may not be my primary concentration in college, it plays a huge role in my academic career. However, this was my first time in a French speaking country, so I have not had much experience with French conversation, aside from with my fellow French-speaking peers and professors. So, when the waiter confronted me and asked a question in French, I was rightfully so caught off guard.

 

 

(Anyway, returning to the restaurant…) Sasha, being from Montreal and growing up speaking French with her family, swiftly answered the waiter. After a few seconds of gathering myself and adjusting my vocabulary, I too answered him (in French, of course). This event made wonder what physiological differences, if any, occurred in my brain when switching between English and French vocabulary. Were different areas of my brain active for French words versus English words and vice versa? This question sparked my interest, so, upon returning to my room I searched for an answer.

Before I try and explain the studies I found, let me give you a quick and easy lesson concerning neuroscience and language. Broca’s area, a region of the frontal part of the brain, is linked to the production of speech, while Wernicke’s area, a region of the temporal part of the brain (slightly above where your ears are), is linked to the comprehension aspects of speech. In order to engage in a coherent conversation with another individual, one must use both of these areas, as the language one hears must be understood
(via Wetumblr_memuxuR4xw1qf721rrnicke’s area) and the language one speaks must be intelligible (via Broca’s area). So, when looking for an answer to my original question about language, I immediately thought that this must be the sole system affected, but boy was I wrong.

 

After some quick searching, I stumbled upon an article by Correia et al., 2014, concerning brain activation in bilingual individuals. The researchers in this study subjected bilingual participants, fluent in English and Dutch, to a series of experimentations in which the participants were placed inside an fMRI and told to listen to a series of words. The words consisted of the names of specific animal species, and the language spoken varied between English and Dutch. The fMRI constructed images of the participant’s brains, highlighting the regions most active during this process. By examining and comparing the fMRI images created by solely Dutch words, solely English words, and a combination of the two, Correia et al. isolated several regions of the brain active for both languages. The main region of activity they observed was the anterior temporal lobe (ATL). This cortical region is associated with semantic memory, that is, memory of physical objects, people, information, and (most important to this study) words (Bonner and Price, 2013). This finding is significant as it provides evidence that semantic knowledge is processed in a language-independent form in the brains of bilingual listeners (Correia et al., 2014). Essentially, this means that as the participants listened the either English or Dutch words, their ATLs become equivalently active for each. So, when I was in the restaurant with Sasha, although I may have been caught off guard by the waiter speaking French, similar regions of my brain became active compared to if the waiter spoke English to me.

Screen Shot 2015-06-07 at 12.05.16 PM

A figure from Correia et al. (2014) depicting the language-independent regions of the brain, one of which being the anterior temporal lobe (ATL)

Another interesting study I found was conducted by Mohades et al. in 2012. In this study, the researchers assessed the brain circuitry associated with language in children aged 8-11 years old. They compared this circuitry in children raised monolingual to those raised bilingual. Through this, the researchers discovered significantly different white matter density in specific brain regions involved with spoken language and comprehension of language. Certain areas of bilingual’s brains contained different densities of white matter in comparison to the brain’s of monolinguals (Mohades et al., 2012). This means that the circuitry of the brain involved with language differs depending on one’s language capabilities. So, in relation to my brain and Sasha’s brain, we have different densities of white matter in specific regions of our brains, since Sasha was raised bilingual (woah).

3DSlicer-KubickiJPR2007-fig6

The type of fMRI imaging used by Mohades et al. (2011) to measure white matter integrity (density).

 

I found both of these articles very interesting because they offer different findings regarding brain activation in bilinguals. In my NBB classes I learn about many regions of the brain discussed in these studies, yet I never knew the role they played in bilingual individuals. With this newfound knowledge, I am interested in doing further research to discover more differences in brain activation associated with language.

~ Ethan Siegel

References

Bonner M, Price A (2013) Where is the anterior temporal lobe and what does it do? The Journal of Neuroscience. 33(10): 4213-4215

Correia J, Formisano E, Valente G, Hausfeld L, Jansma B, Bonte M (2014) Brain-based translation: fMRI decoding of spoken words in bilinguals reveals language-independent semantic representations in anterior temporal lobe. The Journal of Neuroscience. 34(1):332–338

Mohades S, Struys E, Van Schuerbeek P, Mondt K, Van de Craen P, Luypaert R (2011) DTI reveals structural differences in white matter tracts between bilingual and monolingual children. SciVerse ScienceDirect. 1435: 72-80

3 Comments

Posted in Neuroscience, Uncategorized

Tagged , , , ,

Fete de la Musique

Posted on June 25, 2013 by | 3 comments

This past Friday (June 21st) is the annual Paris Fete de la Musique, or the Paris music festival.  European countries such as France have a long history of successful musicians creating magnificent masterpieces.  To this day, we often have the opportunity to listen to street musicians perform in the metro station, on the RER, or just by the side of the streets.  Because of the easily available music in pretty much every single metro station of Paris, you might think that the Fete de la Musique is nothing special.  However, it is completely different.

Notre Dame

The party started around 4pm as musicians began to set up their own speakers and instruments on almost every single street and bar of Paris.  We went to Notre Dame as our first stop and we were already welcomed with all different genres of music from classical to folk to choral to bass-thumping club music.  As we wandered around on the side streets near Notre Dame along with hundreds of other people, stopping at different concerts and listening to different street musicians playing, I noticed my ability to focus on the music I want to enjoy despite all these background noises.  Somehow, my brain was able to do a descent job ignoring noises consisting off motorcycles, tourists asking for directions, nearby musicians, and drunk people singing out of tune.  However, the occasional car honking sounds can still distract me from the beautiful music of the Fete de la Musique.

Musicians at Fete de la Musique

Musicians at Fete de la Musique

A little bit a research shows that there is biological basis behind our ability to ignore background noise and focus on the wonderful melodies of music.  A study done by Perez-Gonzalez et al. (2005) found a type of neuron that will respond to novel sounds but not a repetition of sounds; it is located in the inferior colliculus (IC) of rats, part of the midbrain nuclei that receives input from the auditory cortex and peripheral auditory pathway.  Specifically, this type of neuron is named “detector neuron” and shows stimulus-specific adaptation (SSA) in which these neurons are able to detect all frequencies of sound within the rats’ hearing frequency range, but will stop firing if the same pitch of sound is repeated at 0.5 hertz or higher.  However, the firing of these neurons can be brought back when a sound of a different pitch is introduced (Perez-Gonzalez et al., 2005).  Although discovered in a rat model, it is possible that humans also have the same kind of neurons. This would explain why I was able to filter out constant repeated background traffic noise when listening to the changing notes of a classical masterpiece that a violinist was playing.  However, when a car honked, I would get distracted because this type of detector neuron will fire to the sudden change in pitch of the traffic noise caused by the honking sound.

More recently, research on shifting attention between different sound sources further differentiated between a top-down (voluntary) and bottom-up (involuntary) shift of auditory attention.  For example, I made the conscious choice of focusing on the violinist playing music; this is a top-down shift of attention.  However, when a car honking noise surprised me and caught my attention, it is a bottom-up involuntary shift of attention.  To test the difference in brain activation, Huang et al. (2012) used fMRI while testing 19 healthy subjects on hearing tests.  Specifically, in a 10-second trial, the healthy subjects were informed to wait for a “cue” (sound) at the ear where a subsequent  “target” sound is likely to appear.  After the cue sound, the subjects were instructed to pay attention to the ear that received the cue and press a button as fast as possible right after hearing the target sound.  However, in 20% of the trials the “target” sound is replaced by a novel sound opposite to the ear that received the cue in order to trigger involuntary attention shift (Huang et al., 2012).  The fMRI results showed different activation pattern of the brain between voluntary cued attention shift and the involuntary novel sound attention shift.  For voluntary attention shift, superior / posterior intra-parietal sulcus (IPS), located on the surface of the parietal lobe and precentral areas such as Pontine micturition center (PMC), part of the brainstem and frontal eye fields (FEF), a region of the prefrontal cortex, are more activated.  For involuntary attention shift, inferior IPS, posterior superior temporal sulcus (STS), and temporal parietal junction (TPJ) are more activated.

Intraparietal Sulcus (IPS)

Frontal Eye Fields

Temporoparietal Junction (TPJ)

Superior Temporal Sulcus (STS)

While knowing all these different brain regions can be confusing and might not be necessary, it is more important to recognize the idea that this study demonstrated two types of auditory attention shifts supported by the evidence of different brain activations using fMRI.  One potential flaw of this study is the inherent difficulty to distinguish whether the brain areas activated are due to attention shifting or other pathways that happens to be activated by the auditory stimuli.  In addition, a slightly bigger sample size would increase the credibility of this study. Despite these flaws, combining the more macro view of brain area activations of voluntary and involuntary attention shift to the micro view of specific neurons that fire when a novel auditory stimulus is introduced, researchers have gotten closer to understanding the complex auditory system that enables us to filter out sound waves that are not important and only focuses on the sounds that are more important such as the wonderful music at the Fete de la Musique.

-Eric Yao

References:

Huang S, Belliveau JW, Tengshe C, Ahveninen J (2012) Brain networks of novelty-driven involuntary and cued voluntary auditory attention shifting. PLoS One 7:e44062.

Perez-Gonzalez D, Malmierca MS, Covey E (2005) Novelty detector neurons in the mammalian auditory midbrain. The European journal of neuroscience 22:2879-2885.

 

3 Comments

Posted in Neuroscience

Put on Your Dancing Shoes

Posted on June 25, 2013 by | 1 comment

Last Friday, we had the incredible opportunity to be a part of Paris’ Fête de la Musique, a celebration of music in all its forms. Starting in the evening and lasting well into the next morning, the festival brings thousands of musicians to hundreds of bars, clubs, courtyards, and street corners in all twenty of the arrondissements of the city. Everyone crowds the streets to celebrate, and there is music wherever you turn; oftentimes musicians are so close that you can actually hear multiple performances simultaneously. As the night went on, we found ourselves immersed in an environment filled with new friends, loud music, and lots of dancing. We danced alongside the Parisians to club electronica, gritty rock, solo vocals, drum circles, and even American pop. The instinct to move in synchrony with the music was not only consistent across genres, but also ubiquitous among individuals. This final post of our trip aims to explore the profound and fascinating link between dancing and music.

Venues for Fête de la Musique 2013. A better question: where isn't there music?

One prominent theory to explain movement coordinated with music suggests that this type of synchronized movement simulates music production itself, which may have evolved as a method of social bonding (Levitin and Tirovolas, 2009). The importance of music as a type of honest, yet generalized, form of communication may have lead to activation of reward systems in the brain upon not only personal production of music, but imitating the production of music present in the environment. I personally tend to disagree with this hypothesis. Though I find actual production of music to be the most enjoyable of all, I do not necessarily feel that fingering along accurately to a piano lick is any more rewarding than flailing my entire body to the beat. Though my own personal experiences prove nothing, this theory of pleasure being derived from musical imitation tends to draw skepticism in literature on the topic, as it is not even clear that music is an evolutionary adaptation in the first place.

One of the festival's larger venues.

More recent research, however, takes a different approach to the question. Testing of both musicians and non-musicians suggests that moving to a beat actually enhances perception of the metrical structure (Su and Pöppel, 2012). The experiment that demonstrated this was actually fairly straightforward. Test subjects listened to rhythmic excerpts that maintained a constant tempo throughout and were instructed either to move to the music (e.g. foot-tapping, head-nodding, or body-swaying) or were told to sit still while they listened. Participants were also told to indicate what they felt to be the beat of the music by tapping their finger on the table in front of them. Once the music began, the researchers would occasionally silence the music at random on key beats, though subjects were instructed to continue tapping during these “dropped” beats. The accuracy of the placement of the dropped beat and overall consistency of tapping throughout the sequence were measured and compared between test groups, and researchers found significant improvements in both measures when the subjects were moving versus remaining still. Interestingly, this finding held true regardless of what the consistent tempo was. Whether at 60 beats per minute (the tempo of a very slow ballad) or at 210 bpm (well above the vast majority of music), synchronized movement enhanced understanding of the rhythmic structure.

Further characterization of movement-induced enhancement of beat perception found that this effect is only true of auditory stimuli, and in fact, movement impairs timing extraction in equivalent visual tasks (Iordanescu et al., 2013). This finding implies that synchronized movement may somehow bear a particularly special connection to our interpretation of sound. Could the fun of dancing arise from its ability to increase our sensitivity to rhythmic patterns? That may be what the research suggests. From soon after birth, humans have an innate desire for information and, quickly thereafter, an insatiable need to categorize (Perlovsky, 2010). This ability and, in fact, craving to classify our world has been referred to as the “knowledge instinct,” and this may explain why we so readily appreciate a more intensified and obvious pattern in our aural environment.

All of the rhetorical questions, personal musings, and references to psychological theory in this post are a testament to the real conclusion to this discussion: nobody actually knows why we like dancing so much. Indirect experiments and conveniently intuitive theories of selective pressure can only provide so much insight into the issue; so while science works on solving this highly urgent question, just enjoy the music and keep on dancing.

Dancing (if you can call it that) in Homo sapiens.

 

-Max Farina

 

References:

Iordanescu L, Grabowecky M, Suzuki S (2013) Action enhances auditory but not visual temporal sensitivity. Psychonomic Bulletin & Review 20: 108-114.

Levitin DJ, Tirovolas AK (2009) Current advances in the cognitive neuroscience of music. Annals of the New York Academy of Sciences 1156: 211-231.

Perlovsky L (2010) Musical emotions: functions, origins, evolution. Physics of Life Reviews 7: 2-27.

Su YH, Pöppel E (2012) Body movement enhances the extraction of temporal structures in auditory sequences. Psychological Research 76: 373-382.

1 Comment

Posted in Neuroscience, Uncategorized

Tagged , , , , , ,

Confessions of a Coffee Addict

Posted on June 25, 2013 by | 2 comments

With the addition of new coffee vendors on Emory’s campus over the past three years, combined with the excellent surrounding breakfast hotspots, I have become one to regularly appreciate and truly enjoy a hot cup of coffee. Whether the coffee be from Starbucks, Rise-n-Dine or Dunkin Donuts, I am victim to daily expenditure at these vendors for my morning (and sometimes evening) caffeine fix. Now that my time in Paris is approaching its end, I will readily admit that I had routed the closest Starbucks locations to my dorm and to the building where we take classes (before my departure from New York). I saved those directions in my phone; anticipating daily visits to this familiar coffee shop.

My pre-departure routing of Starbucks to the Accent center (where we take classes)

When I realized that it would be a daily struggle to somehow go to Starbucks before my early morning class (thanks to the reliability of the French subway system), I decided to give the conveniently located French coffee (on campus) a chance. My first experience with French café was at the Cite Universitaire cafeteria, as I was presented with a Dixie-cup size equivalent cup of black coffee. No sugar, no milk…but I was pleasantly surprised. I didn’t realize how strong the coffee would be and I can safely say that 3 cups of the café coffee was overkill…

All throughout Paris, I have noticed that the café comes in one size: about a quarter of the size of the regular coffee we get back in America. The coffee is quite deceiving, as the small cup actually keeps me energized despite its miniscule volume. I quickly realized that coffee in itself is a part of French culture, as many cafes throughout the city orient their tables and chairs to face the streets—this way, people can enjoy a cup of coffee and “people watch”. I rarely see Parisians eating lavish breakfasts (doesn’t stop me though…); rather, they enjoy a simple black coffee with the morning paper. French culture, to me, seems to emphasize simplicity and reservation. A cup of coffee, then, serves as a means to collect your thoughts and appreciate the beauty of France while simultaneously obtaining a needed jolt of energy. A cup of coffee transcends the traditional role of a breakfast drink, as “une tasse de café” is readily available (and encouraged) at any time of day.

French breakfast at a local restaurant (notice the tiny coffee...)

One of the classes we are taking here is related to body enhancement and the new, innovative technologies that can alter normal human function. During class one day, Dr. Crutcher shared with us some research that suggested the caffeine fix from our morning cups of coffee actually yields some physiological effects besides just enhanced alertness. In the past, researchers found that caffeine can increase anxiety in the short run, but increased doses of caffeine over time (via more coffee, for example) can lead to a diminished effect because of the build up of tolerance (Rogers et al., 2010). Recent research suggests that caffeine, readily found in coffee, may modify the way the different brain areas react to social threats (Smith et al., 2012). What are the neurological implications of this? Smith et al. (2012) set out to determine if there really was a relationship between anxiety, threatening signals, caffeine and the brain.

How did they do this study? After obtaining a group of subjects, the researchers gave the participants in this study received a fixed amount of either caffeine or placebo in two different sessions. During each session, the participants were placed in an MRI machine that would give researchers an fMRI scan (functional magnetic resonance image). An fMRI is basically a way to measure the changes in blood flow in the brain. Changes in blood flow in the brain represent changes in activity and activation in the different areas of the brain. (For example, if an area of the brain is in use, then there is increased blood flow in that area.) While in the MRI machine, participants were asked to perform an “emotional face processing task” (EFPT). This task involved participants being presented with different faces, each representing different emotions, and they had to match the presented face to a target face at the top of the screen. (Similar to a matching game!) After seeing the faces and doing the matching task, the participants would rate their anxiety and mental alertness (compared to before the task) via a questionnaire. Researchers also measured their blood pressure (before and 2 hours after the treatment of either the placebo or caffeine) (Smith et al., 2012).

Turns out that when the participants who were administered caffeine saw the threatening faces, that is the angry and fearful faces during the EFPT, there was increased activation of a brain area called the “midbrain periaqueductal gray area” and decreased activation in another area called the “medial prefrontal cortex” compared to the placebo group (Smith et al., 2012). Participants who received the caffeine dosage had higher self-rated anxiety on the questionnaires and their diastolic blood pressures were higher also! However, the exact neural mechanisms and implications of how these areas actually process threatening images and scenarios are still unknown (Smith et al., 2012). So what was the point of this study then? Smith et al. (2012) suggest that these brain areas, that showed changes in activity, are actually related to social threat processing and anxiety in humans. Because there were actual changes in blood flow in these areas in response to threatening or anxiety-inducing faces, only in the light of a caffeine dosage, it seems to be that caffeine is modifying the patterns of activation in the brain. A daily dose of caffeine, in the form of coffee for most of us, then, can possibly affect the way we perceive threats and can possibly affect how anxious we are compared to when we do not consume caffeine.

Yum

As with almost everything that seems too good to be true, in this case a delicious cup of French coffee, this study seems to suggest that loading up on multiple cups of coffee a day might not be the best idea. But, I don’t really plan on giving up my black Americano any time soon (especially since I’m leaving France soon and am already having French coffee withdrawal).

-Noareen Ahmed

References:

Rogers, P, Hohoff C, Heatherley S  (2010) Association of the anxiogenic and alerting effects of caffeine with ADORA2A and ADORA1 polymorphisms and habitual level of caffeine consumption. Neuropsychopharmacology 35: 1973–83.

Smith J, Lawrence D, Diukova A, Wise R, Rogers P (2012) Storm in a coffee cup: caffeine modifies brain activation to social signals of threat. Scan 7: 831-840

2 Comments

Posted in Neuroscience

Tagged , , , ,

The Broken Escalator Effect (It’s Real)

Posted on June 19, 2013 by | 8 comments

Every day we take the Paris Metro and RER to and from class. It’s a relatively painless trip, except when there’s a strike going on (which has been almost every day). One day last week, as our motley crew filed through our favorite station, Châtelet, to transfer trains, we reached our favorite stretch of the station: the moving walkways. I approached the walkway without hesitation, took a step onto the belt, and immediately felt myself jolted awake by a sense of falling. As it turned out, the moving walkway was broken that day, and pedestrians were just using it as a normal path. I followed suit and laughed silently at how funny I must have looked to anybody who saw me nearly fall on my face.

Our favorite Metro stop

Later that afternoon, on the return journey, I’d had ample time to wake up during the day. As we approached the same collection of moving walkways, I made sure to take note of the functionality of the machines. They were all still broken, but I decided to follow the crowd and walk along one of the belts anyway. This time, I approached, took a step, and felt jolted again! I was shocked at my brain’s miscalculation despite my conscious awareness that the walkway was stationary. I presumed that it had to be some sort of perceptual memory that I had for moving walkways. Perhaps because reality wasn’t matching up with what my brain had learned to be true of “people-movers” countless times before, my mind was having trouble adjusting. I decided it was worth a search in the literature when I got home.

No "broken escalator effect" here

What I found was not only reassuring for my vestibular system, but also immensely interesting. There is an extensive collection of scientific research on what has been called the “broken escalator phenomenon,” (Reynolds and Bronstein, 2003). Evidently, the effect is more evident on moving walkways, but because nobody knows what to call them, the original authors of the phrase decided to go with escalator instead. Once the phenomenon became well known as a common occurrence in city-dwellers, researchers sought to describe what was actually happening to cause this “feeling of uneasiness” despite absolute consciousness of the fact that the conveyor was not moving

First, experimenters had subjects walk on a short, stationary moving walkway a few times while measuring walking speed, postural sway, and muscle contraction (Reynolds and Bronstein, 2003). Afterwards, the experimenters turned on the walkway and had the same subjects board the machine. Not surprisingly, subjects made several physical changes as they got used to the moving version, but the most significant change observed was in the actual velocity of movement just prior to boarding. Naturally, the subjects increased their pace by .3 m/s in order to minimize being jerked by the belt. This is similar to what happens to us in everyday life. We encounter a majority of moving walkways in their “on” position, and we become accustomed to increasing pace, leaning forward, and flexing our leg muscles as we approach them. Next, the researchers informed the subjects that the walkway would be turned off, and in fact, they could see so for themselves. When they approached the walkway this time, all subjects stumbled, and many were shocked or laughed at the occurrence. Analysis of the physiological data showed that approach velocity, trunk lean, and muscle contraction took place at levels in between normal walking values and the values seen when subjects were accustomed to the moving walkway. It seemed that the brain was confused by seeing a normally moving pathway in a motionless state, and addressed the situation by “hedging its bets” so to speak. Interestingly, repeating a second trial with the “off” walkway shows no signs of distress. The brain learns quickly to adopt normal walking motor programs for the motionless walkway. Further studies have shown that skin conductance also increases just prior to experiencing the “broken escalator phenomenon,” implying that subconscious, fear-based mechanisms are at play (Green et al., 2010). This may explain why the hiccup occurs even when one consciously recognizes that normal walking will suffice.

Primary motor cortex, where the researchers stimulated.

Given that this phenomenon is strikingly similar to the lack of balance that many neurological disease patients experience, further studies aimed to find ways to modulate to the occurrence (Kaski et al., 2012). Recently, researchers tried this using a technique called transcranial direct current stimulation (tDCS), which is a lot like connecting a battery to your skull, except it’s scientific. Subjects went through the same experimental procedure as in the first study, but just before had a small anodal current passed through their brain for 15 minutes before the moving platform phase of testing. The researchers targeted the primary motor cortex, an area of the brain responsible for executing movement and storing motor memories, or the actual plans that the body uses to coordinate movement. The researchers believed that the broken escalator effect occurred due to an inability to suppress the brain’s default “moving walkway motor plan,” so activating primary motor cortex would cause the phenomenon to become even more extreme. Indeed, the subjects who received the electrical stimulation showed a larger broken escalator effect and took more trials to adjust to the stationary pathway than control subjects who received no stimulation. Though the nature of the experiment did not necessarily prove that the broken escalator effect is due to overactive motor memory, the results are significant in that they show it is possible to manipulate gait and motor problems with relatively simple technology. tDCS is fairly cheap and straightforward compared to other similar technologies, and its lack of precision actually lends itself nicely to working with the distributed neural systems of locomotion. Though this study used tDCS to worsen a locomotor problem, this same system may soon become a useful tool in neurological diseases that show locomotor symptoms such as stroke, Parkinson’s multiple sclerosis, and Alzheimer’s disease.

 

-Max Farina

 

References:

Reynolds RF, Bronstein AM (2003) The broken escalator phenomenon. Experimental Brain Research.

Green DA, Bunday KL, Bowen J, Carter T, Bronstein AM (2010) What does autonomic arousal tell us about locomotor learning? Neuroscience 170: 42-53.

Kaski D, Quadir S, Patel M, Yousif N, Bronstein AM (2012) Enhanced locomotor adaptation aftereffect in the “broken escalator” phenomenon using anodal tDCS. Journal of Neurophysiology 107: 2493-2505.

8 Comments

Posted in Neuroscience

Tagged , , , , , , ,