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Nearly every morning for the past four weeks, I go to Le Pain Quotidien on Rue de Charonne at 9:05, sit at the long wooden table, order “deux oeufs BIO à la coque et un café crème avec lait de soja” (two organic soft-boiled eggs and a soy latte), and enjoy a nice breakfast before my first class begins at 10. After Dr. Shreckengost’s morning class, I take a leisurely walk from the Accent Center to Le Bar à Soupes, also on Rue de Charonne, wait outside the restaurant until the owner opens the door at 12:00pm, and order one of the six soups of the day “à emporter” (take away).

Le Pain Quotidien and La Bar à Soupes in relation to the Accent Center

Both the waitress at the Le Pain Quotidien and the owner of Le Bar à Soupes identify me as a regular customer. I no longer need to order when I go to breakfast because the waitress knows I order the same thing every morning. The soup bar owner even gave me a Soup Stamp Card to fill up and receive a free soup after 10 purchases! Many friends on my study abroad trip have quickly surmised from my daily routines that I am a “creature of habit,” so I began to wonder how we form habits.

My filled-out Soup Card!

Do I keep going back because of the comforting food and friendly faces or is there another underlying, physiological reason? What differentiates a habit from a choice?

First, let’s start with the definition of habit. From a scientific perspective, habits are “a form of goal-directed [automatic] behavior” (Aarts and Dijksterhuis, 2000). Goals can activate habitual actions. Take an example of biking to school every day: once someone develops this habit, the activation of the goal, going to class, may automatically elicit a habitual response, biking.

Now that we understand what habits are, let’s examine how habits may actually form in our brains!

In a study conducted by Wang et al. (2011), researchers investigated the mechanisms underlying learning and forming habits. Prior research revealed the importance of the neurotransmitter known as dopamine (DA) in habit learning. In both human and rodent models, an impaired ability to form habits correlated to degeneration of dopaminergic neurons. Wang et al. (2011) examined the importance of DA even further by looking at the impact of specific receptors on DA neurons. The researchers bred mice that lacked N-methyl-D-aspartate receptors (NMDARs) on their DA neurons (NR1 mice). NMDARs are glutamate (a type of neurotransmitter) receptors found in nerve cells that play a crucial role in synaptic plasticity—the ability of neuronal synapses to change shape or function in response to activity – and memory function. Wang et al. then hypothesized that the NR1 mice, lacking NMDARs on their DA neurons, will have impaired habit learning as compared to normal, wild type (WT), control mice.

First, researchers tested if WT mice differed from NR1 mice in various abilities other than habit learning, such as fine motor movements, balance, general endurance, anxiety levels, and object recognition. The WT and NR1 mice did not differ in their abilities, proving NR1 mice to be suitable models for testing differences in habit learning. To test the impact of the NMDAR deletion on DA neurons cellular processes, the researchers recorded both WT and NR1 mice DA neuron activity in response to the dopamine receptor agonist apomorphine through electrodes inserted into the ventral tegmental area, an area of the brain that serves as the origin of dopaminergic cell bodies. The researchers discovered reduced activity in the NR1 mice, indicating the NR1 mice DA neurons did not exhibit as much activity in the presence of dopamine or dopamine agonists as compared to WT controls. Additionally, the NR1, as compared to WT, DA neurons showed decreased responses during paradigms testing reward-predicting cues over three days, showing that the NR1 mice exhibited greatly lowered bursting responses, known as DA neuron blunting, and that NMDARs play a crucial role in dopaminergic cell activation.

Figure 8 – Wang et al.
The researchers designed these Water-Filled Zigzag Maze-Based Habit Tasks to more obtain more direct measurements of habit learning by eliminating the competition factor between “spatial” and “habit” memory systems the NR1 deletion may have skewed. You can see a significant difference habitual learning ability between NR1 mice (blue) and WT mice (green).

To investigate habit learning deficits in NR1 mice, the researchers tested both NR1 and WT mice in a lever-pressing operant-conditioning task. This task, pressing a lever to obtain food, can transform goal directed responses into habitual responses through extensive training. Over time, mice typically become desensitized to outcome devaluation, the decrease in reward value. Wang et al. (2011) discovered that the NR1 mice showed a significant difference in lever presses from Non-Devalued to Devalued outcomes, suggesting that the NR1 mice failed to develop the lever pressing habit, and their actions remained goal directed. The researchers continued to test habit learning through various maze-like paradigms and discovered that the NR1 mice showed habitual learning, but not spatial memory, impairments as compared to WT controls.

Wang et al. (2011) studied the importance of DA neuron NMDARs in habit learning and formation both on a behavioral and a cellular level, providing various methodological analyses for their findings. Their control experiments testing the differences in behavior for NR1 and WT mice provided clear evidence that the researchers could use the NR1 mice to only test behavioral differences in habit learning. Additionally, the researchers discovered an interesting phenomenon exhibited in some DA neurons – decreased and then rapidly increased responses to negative experiences – suggesting the importance of NMDARs extend beyond habit formation of reward stimuli and may apply to habitual learning through the reward of escaping negative stimuli (Wang et al., 2011).

The findings of this study not only provide the scientific community with better understanding of the crucial role NMDARs play in habit formation but also lay the groundwork for future researchers to better understand the underlying mechanisms of habit disorders, such as Obsessive-Compulsive Spectrum Disorders. Who knows, maybe even executives at Starbucks rely, in part, on the science behind how and why people form habits to boost their sales and marketing efforts.

Getting lunch at Le Bar à Soupes – yum!!!

For me, my taste buds thanks my DA neurons NMDARs for their role in my behavior to seek yummy foods at the same places every day. Based on the information in Wang et al.’s study and the Aarts and Dijksterhuis (2000) definition, I am not sure if my daily trips to Le Pain Quotidien and Le Bar à Soupes have fully transitioned to a “habit” as, without the delicious food and friendly faces, I would likely seek other rewards. While habits are the result of reflexive and automatic behavior (Dolan and Dayan, 2013), I still make the reflective decision to seek the reward my reliable breakfasts and lunches provide me. I find comfort in routine, especially amid a busy schedule in an unfamiliar country. While many people use the colloquial phrase “creature of habit,” I think of myself as more of a creature of conscious goal-directed behavior… who likes consistency in my rewards 🙂

References:

Aarts H, Dijksterhuis A (2000) Habits as knowledge structures: automaticity in goal-directed behavior. Journal of Personality and Social Psychology 78(1): 53-63

Wang LP, Li F, Wang D, Xie K, Wang D, Shen X, Tsien JZ (2011) NMDA Receptors in Dopaminergic Neurons Are Crucial for Habit Learning. Neuron 72(6): 1055-1066.

Dolan RJ and Dayan P (2013) Goals and Habits in the Brain. Neuron 80(2): 312-25.

Bonjour family, friends, and strangers of the virtual world!

I would be lying if I said I was always on time to things back in the states, but somehow, in some odd fourth-dimensional way, “Parisian Time” has hit me hard. I’m always fifteen minutes late everywhere, unless I’m going to class (in which case I’m only a minute late), and if I’m on time it’s because I ran for my life to catch the train.

Jokes on me aside, people go about things real slowly here in Paris (even Monday mornings on the Metro). At the local boulangerie (bakery) I could be the only person in the store but the barista will still take nine minutes (yes – I’ve counted) to make my café au lait (espresso with milk).

Café au lait

Why is that? Why do I want to function so much faster back at home than I do in Paris? Why are some Parisians gallivanting about their day without concern for the time? What causes the difference in how we perceive time? Why can’t people just give me my coffee already!

Interval time, the type of time that we use to perceive, estimate, and discriminate how long something has been going on for (the kind of time we use to estimate how long it’s going to take to get to class), is controlled by parts of our brain known as the striatum and cerebellum (Coull et al., 2011). The striatum is a region of the brain responsible for producing dopamine, a neurotransmitter that’s associated with one of our brain’s reward pathway (the striatum is what gets activated when I feel like I’ve done something great – like the satisfaction that comes from being on time). The cerebellum has many functions, but is most commonly known for playing a role in motor control and cognitive functions that also influence time (i.e., consciousness, self-awareness, and emotion). Science aside, what does interval time have to do with why my midtown Starbucks barista makes my low-fat, sugar-free iced caramel macchiato faster then the lady at the boulangerie making my simple café au lait?

Striatum and Cerebellum

Interestingly enough, there’s been a recent study by Pollatos et al. on how interoceptive processes affect our perception of time. Interoceptive processes are the systems in our bodies that allow us to sense and perceive the physiological conditions that are occurring within our bodies. An example of an interoceptive process is someone paying attention to how quickly his or her own heart is beating.

The study wanted to particularly explore how one’s perspective of their physiological responses during an emotional state (like how you stop breathing for a second when you kiss that special someone on the top of the Eiffel Tower – nope, haven’t done it yet, still waiting to meet that perfect Parisian guy who also speaks English) affected their perception of time.

Eiffel Tower

The study hypothesized that time contraction (perceiving less duration of time than has actually passed) and time dilation (perceiving more time than has actually passed) will be more pronounced in groups that were focused on their internal bodily processes as opposed to those focused on external stimuli.

It’s believed that when you’re experiencing emotions related to fear, you experience time dilation, whereas experiences that make you laugh lead to perceived time contraction (Buhusi and Meck 2005). Pollatos et al. took 254 participants, showed them a documentary (served as a control that wouldn’t elicit emotions), a German horror movie (to elicit prolonged fear), and Ice Age III (for comical effects), and separated the subjects into two groups. One was asked to focus on their bodily processes while watching the films (the interoceptive focus group) and the other was asked to focus on the film so they could answer a questionnaire on the content of the films (the exteroceptive focus group). All participants were subsequently asked to answer the same survey to which Pollatos et al. used the retrospective time paradigm, a way to measure a subject’s judgment of time without them knowing about it (sneaky…).

They ended up finding that subjects who focused on their internal physiological responses experienced an accentuated subjective time perception. Subjects who focused on their bodily functions while watching scared watching the horror film, exhibited greater time dilation to those subjects who did not pay attention to their bodily functions. Similarly, subjects who focused on their interoceptive processes while watching the comedy exhibited greater time contraction to those subjections who focused extrospectively. Because the hypothesis was supported, Pollatos et al. concluded that the more aware a person is of ongoing bodily functions, the more influential an emotional experience is on a subjective time experience.

Perhaps, Parisians are having a great time. Why wouldn’t they be? The wine is great, the baguette’s are fresh, the architecture is phenomenal, and the paintings in some of the museums are breathtaking! So, the feeling of joy may elicit time contraction, and they’re always walking everywhere making it seem like they’re at least slightly aware of their bodily functions, exacerbating their time contraction. With them thinking that time is passing slowly, of course they’re bound to take their time and be late to things! I exaggerate in my analogy, but it’s a thought!

Art at Musée d’histoire de la médecine

Lastly, the study addresses that one of the things they want to focus on in the future is what factor age plays in subjective time distortion. Ironically, now that I think about it, the 20-something year old barista at the Le Pain Quotidien around the corner made my cappuccino a lot faster than the 40-something year old lady at the local boulangerie.

Or maybe the 40-something year old lady has more to worry about or more on her mind that causes stress and induces fear making her less aware of her bodily functions, which would cause time dilation. This might explain why it takes her 9 minutes to make my café au lait instead of the normal three. Or, she could just not like me.

Work Cited.

Buhusi CV, Meck WH (2005) What makes us tick? Functional and neural mechanisms of interval timing. Nat Rev Neurosci 6: 755–765.

Coull JT, Cheng R, Meck WH (2011) Neuroanatomical and neurochemical substrates of timing: a review. Neuropsychopharmacology. 36, 3-25.

Kreibig SD (2010) Autonomic nervous system activity in emotion: a review. Biol Psychol 84: 394–421.

Pollatos O, Laubrock J, Wittmann M (2013) Introceptive Focus Shapes the Perception of Time. PLOS One. 9: 86934

“Mom! They offer French here! I want to take French!”

These were some of the first words I told my mom after we moved from California to Georgia when I was in 8th grade. Finally, after all this time, I was going to be able to learn the language I’d always wanted. I’m part French!

It’s part of my blood! I was going to learn the language of my people, until I told my mom   the grand plan.

“No Kayleigh, Spanish will be more practical in America, especially if you want to become a doctor.”

Well, there goes my dream of becoming fluent in the language of my people. And so, I proceeded to take Spanish, for 5 years. Hooray for proficiency!

Now that I’m in Paris, with little to no experience in speaking French. (Oh mom, why did you not let me learn?), I tend to think back on this time in my life. As I travel around the city, trying to learn new words and phrases, it becomes increasingly apparent that when I speak the little French I do know, nobody understands me. I would think, since I’m pronouncing the words just like the native Parisians, that they would understand me perfectly. Although, maybe it’s possible… could it be that I have an accent? Is my accent so thick that they cannot understand that when I say “poulet et fromage” I mean chicken and cheese? Now that I think about it, that’s probably why they proceed to giggle at my attempts at French and then start to speak to me in English.

I can’t blame them though. Going from your home country to a completely different place, with an entirely different language, causes some people to forget that when speaking another language, they too have an accent. Yet, it is so hard for native speakers of a language to comprehend non-native speakers, even when said non-native speaker has had practice in enunciating the accent.

A 2015 study done by Romero-Rivas et al. attempts to answer this question. “Processing changes when listening to foreign accented speech,” focused on two main issues about processing language from a non-native speaker: first, whether fast adaptation in the brain occur at the acoustic and/or lexical level during speech comprehension and whether semantic processing in the brain is affected after listeners have gotten better at comprehending foreign accented speech.

Figure 1 from Romero-Rivas et al. 2015 showing rating on a scale of 1 to 5 of accent strength

So the set up for the experiment went a little something like this, the researchers recruited 20 native Spanish speakers (I guess my mom was right!), 12 women and 8 men, with the majority being from Catalonia, Spain. This was done so that the majority of them spoke in the same dialect. Each person had 208 sentences played to them from both native Spanish speakers, and non-native Spanish speakers. The non-native Spanish speakers were native speakers of Greek, Japanese, Italian and  French. Each sentence was repeated 4 times, a standard sentence spoken by a native Spanish speaker, a standard sentence spoken by a non-native Spanish speaker, a sentence with a semantic error spoken by a native Spanish speaker and a sentence with a semantic error spoken by a non-native speaker. This semantic error is a mix up in the meaning of the words in the sentence. These sentences were recorded by the non-native speakers and played back to the native Spanish speaking participants, at will and in a soundproof room (Romero-Rivas et al. 2015)

I guess this whole set up is kind of similar to my struggles here in Paris. I mean, I’m pretty sure I sometimes mix up some Spanish in my French, add some SIs when there should be some OUIs. Maybe say poulet Y fromage instead of poulet ET fromage. There are those semantic errors.

Figure 2 from Romero-Rivas et al. 2015 showing EEG spiking

Anyway, neural recordings were taken by an electroencephalogram or EEG for short. Just imagine the spiking you see from a EKG on television. You know the one when the person is in the hospital and the machine is going *beep, beep* and the little spikes show the heart beating. Now imagine that same concept, but for the brain. They measured three types of spikes associated with neuronal language processing, P200, N400 and P600(Romero-Rivas et al. 2015). These recordings allowed for more in depth analysis of what was really going on when native speakers had to listen to foreign accents over a brief period of time.

After all of that testing, EEG reading and analyzing, the experimenters were finally able to come to certain conclusions about why French people can’t understand me when I speak! I mean why it’s harder to understand non-native speakers. The experimenters found that listeners do not improve at discerning phonetic/acoustic parts of foreign-accented speech after short term (25 minutes) exposure to it. However, information from native speaker’s internal lexicon (basically a dictionary for your brain), allows listeners to recognize and retune phonetic and acoustic variations into familiar vocabulary, making it possible for the listeners to improve at recognizing, retrieving and integrating the incoming foreign-accented speech. As for semantic violations, those were easier to process for native Spanish speakers as compared to non-native Spanish speakers. There is a type of reorganizer in the brain that adjusts for those violations from native speakers but not from non-native speakers (Romero-Rivas et al. 2015).

           Now it makes complete sense as to why when I go and order my Prince Street bagel sandwich with my exotique fruit smoothie, they don’t understand me. It’s harder for them to process the information that is coming out of my mouth because they are not exposed to English speakers often enough to process the accent fast enough. Not only that, but my accent is most likely thicker than those tested since I have little to no experience with French at all. Even when I say orange, which is exactly the same in English and in French (go ahead, look it up), the Parisians still don’t get it. To be fair, this is probably also due to the fact that I tend to speak in a Spanish accent when I speak foreign languages. It’s the only accent I know, so I can’t help it. I try French accents, but they just don’t come out right. I’m learning though, so that counts for something right? Maybe one day they will finally be able to understand my French.

Works Cited

Romero-Rivas C, Martin CD, Costa A. Processing changes when listening to foreign-accented     speech. Frontiers in Human Neuroscience. 2015;9:167. doi:10.3389/fnhum.2015.00167.

Map of Catalonia: http://deadlinelive.info/2014/09/29/spain-mounts-roadblock-to-catalonia-          independence-vote/

Versailles, the site of which the Treaty of Versailles was signed and which was home to arguably the most talked about French royal couple, King Louis XVI and Marie Antoinette, is a beautifully constructed piece of art located about an hour away outside the Paris city limits.Visiting this enchanting palace was essentially number one on my Parisian bucket list and I couldn’t possibly let this opportunity pass me by. However, little did I know what I was getting myself into. Yes, I heard that this palace covered over 2,000 acres including 230 acres of gardens. And yes, I was well aware of the fact that it is recommended to take 2 days to see Versailles in all of it’s glory. However, I did not imagine that we (Beatrice, Maria, and I) would literally walk through ALL 2,000 acres (OKAY! Maybe we just explored about 35 acres). Let me not give you the wrong impression though,Versailles is by far the grandest thing I’ve ever seen in my life and perhaps my favorite landmark in France I’ve visited since my stay here in this beautiful country! However, as the day progressed, my feet grew weary and if my limbs could talk, I’m sure they wouldn’t have had anything nice to say to me.

From Cite Universitaire to Versailles

When we arrived to Versailles, Maria, Beatrice and I were so fascinated by the immense beauty of the castle that we immediately pulled out our phones to snag some photos. We hardly realized that the line was growing to get inside! Once our photo-op fix was satisfied, we joined the line and waited approximately 1½ hours to get in. Once we were in, we received our maps and set out on a mission, our goal was to see the palace, mainly the Hall of Mirrors (historically where the Treaty of Versailles was signed), Marie Antoinette’s estate, and virtually everything else in between. There was so much to see! I could not believe it. The palace was huge, and the gardens were vast!

The chateau!

By the time we walked throughout the palace, my feet were tired and we still had to cross from one end of the garden to the next to see Marie Antoinette’s estate! In all we walked at least 5 miles by the time we got to the estate; by this time it was around 4pm (We entered around 11AM, I blame it on our multiple photo-ops…) and my legs were crying! Maria and Beatrice however encouraged me to engage in positive thoughts and that my pain was all in my head. The art of mindfulness which is bringing attention to the state of your present being and having a nonjudgmental attitude towards it, is something that I’ve started practicing at the start of this year to help me cope with the daily stresses of life. Once I regrouped, I became mindful of the present so that I could take in the pleasures of Versailles appropriately and Voila! my leg pain vanished and my mood and energy increased.

From left to right: Me, Maria, Beatrice

Interestingly enough, a study done in 2011 looked at the effects of how practicing mindfulness attenuates pain. Gard et al. hypothesized that modulation through mindfulness involves decreased activity in the brain pre-frontal cortex (PFC), and increased activation in regions involved in sensory processing of pain, such as the posterior insula and the prefrontal cortex. To perform this study, the researchers recruited experts on the practice of mindfulness and individuals who had no experience with this sort of meditation. They placed an electrode in participants left arm. Two conditions were observed, a mindfulness condition and a baseline condition. During the mindfulness condition, participants were asked to bring their attention to the skin surface underneath the electrode on their forearm and to observe the sensations related to the stimuli, making sure to be mindful of the stimuli. During the baseline condition, participants were instructed to not engage in any form of meditation. Three transcutaneous stimuli were randomly delivered. At the end of each test, participants were asked to rate the intensity, unpleasantness, and anxiety of anticipation for the stimuli.

Pain (a) intensity (b) unpleasantness (c) anticipatory anxiety ratings for mindfulness practitioners and control.

The researchers found that experts in mindfulness had statistically significant lower reported scores for unpleasantness when they implemented their mindfulness technique as opposed to when they did not implement their technique. For controls there was no significant difference in their self-reported unpleasantness scores for baseline and mindfulness. For pain intensity, there was no observable significant difference between controls and mindfulness practitioners. This suggests that for experts they are able to perceive their pain differently which becomes their reality.

Activation of brain due to stimulation. A) Experts B) Control

The researchers also found increased posterior insula activity and decreased lPFC activity when participants (both experts and control) were administered the sensation and practiced mindfulness. They proposed that focusing attention on the sensory aspects of the stimulus is related to increased activation in the posterior insula, which is thought to be involved in  sensory processing. The second component of mindfulness, the nonjudgmental and accepting attitude, could be described as cognitive disengagement, and thus an absence of cognitive control, which is why there is a  decrease in the lPFC.

Me, being mindful.

My ability to be mindful of my weary feet and to accept my circumstance for what it was, allowed my perception of my pain to diminish drastically! Who knew that this coping technique I have so recently learned could positively affect my body such a way? Because of this technique, I was able to enjoy all of Versailles and felt pretty accomplished in the end. Versailles was totally worth it!

References

Gard T, Holzel B, Sack A, Hempel H, Lazar S, Vaitl D, Ott U (2011) Pain Attenuation through Mindfulness is Associated with Decreased Cognitive Control and Increased Sensory Processing in the Brain. Cerebral Cortex 22(11): 2692-2702.