Tag Archives: Memory

Walk-a-holic

Google Map directions of the 5-minute walk from the ACCENT center to Pause Café.

“It’s a 20-minute walk,” sighed my American friends, complaining that it was “too long.” It was our first week in Paris on our study abroad program, and we were planning on going to a café. After Google maps indicated that the metro stop was far from the original café, we ended up going to Pause Café. It was on the corner of the street near the ACCENT center, where our daily classes are held.

 

Image of Pause Café.

I was shocked by the lack of energy that we had. Looking around us, Parisians were walking from place to place without breaking a sweat. Walking for twenty minutes, even thirty, was typical for a Parisian. This got me thinking, how different would my life be if I lived in Paris. In Atlanta, shops and restaurants were far apart, sidewalks were narrow, and the city was difficult to explore without a car. But in Paris, everything was nearby, and sidewalks were wide. If I were to walk this much every day for the rest of my life, how would that impact my health?

Exercise is known to have many health benefits. A fact that has been ingrained in my mind since elementary school. What I knew was that exercise could prevent heart attacks and diseases, but not its effect on the brain.

Researchers show that exercise improves memory, specifically our memory of certain places and events (Cassilhas et al., 2016). The anterior hippocampus provides us with the ability to imagine our house and move around our neighborhood (Zeidman and Maguire, 2016). As we get older the hippocampus decreases in volume resulting in increased forgetfulness (Raz et al.,2005). However, there may be a way to halt those effects and possibly reverse them.

Erickson et al. (2011), reveal in their study that physical exercise improves our long-term memory, specifically our navigational memory. By exercising 3 times a week for one-year, participants had an increase in the volume of their anterior hippocampus. However, participants who did not exercise had a decreased anterior hippocampal volume. Overall, the study showed that only the decreased volume in the anterior hippocampus can be reversed with exercise, but not other parts of the hippocampus. This is a well-designed experiment because 120 participants were involved in the study, which makes the results more applicable to the general public by representing different types of people in the population. The differences in the size of the anterior hippocampus can be better observed and statistically tested with this large number of participants. Further, by testing participants prior to the exercise protocol, after 6 months, and after one year, we can look at the effects of exercise on the anterior hippocampal volume both in the short-term and long-term.

Graphs of the increase in the volume of the anterior hippocampus for the exercise group (blue line) compared to the decrease in the volume of the anterior hippocampus for the control (red line), evident in both the left hemisphere and the right hemisphere of the hippocampus.

Writing this now, I regret missing that 20-minute walk because I now know that a little exercise every day goes a long way in improving my memory. This leaves me wondering, is there a certain time frame when I should be exercising after learning new material?

Researchers performed a study to test whether there is an appropriate time to exercise after learning to improve memory recall (Van Dongen et al., 2016). Participants were assigned into three groups; those who exercised immediately, those who exercised after 4 hours and those who did not exercise. They learned to associate a certain object with a location (refer to image below).The researchers then asked the participants to recall that association. The results showed that exercising 4 hours after learning instead of immediately after enhanced participant’s ability to remember those associations compared to those who did not exercise. Hence, properly timed exercise can enhance long-term memory. The researchers strengthen their conclusion by controlling for problems that could affect the results.Such as having half the participants perform the task at 9AM, while the other half perform it at 12PM. This accounts for the differences in performance at different times of the day, which ensures that improvement in memory recall is occurring due to exercise.

Image of task protocol: associating an object with a location. The orange box represents the study phase, while the blue box represents the testing phase.

So, my elementary school teacher was right after all. Exercise is important for a healthy heart and, as it turns out, a healthy memory. Not only does this motivate me to exercise more often, but also, these studies give me hope for new intervention methods for patients with memory recall deficits. An example would be Alzheimer patients, who struggle with navigating the world (Weller et al., 2018). Another would be patients with major depressive disorder, who have memory impairments in encoding and recalling information (Gourgouvelis et al., 2017). It is cases like these that highlight the importance of understanding the impact of exercise on memory.

Now, when my friends and I have the option between using the metro or walking for 20-minutes, we choose the latter. Living in Paris for 4 weeks today, I have assimilated with the Parisian way of life. I am now able to walk in Paris for hours without the slightest soreness in my legs. It has become my new way of life.

 

References:

Cassilhas, R. C., Tufik, S., & de Mello, M. T. (2016). Physical exercise, neuroplasticity, spatial learning and memory. Cellular and Molecular Life Sciences, 73(5), 975-983.

Erickson, K. I., Voss, M. W., Prakash, R. S., Basak, C., Szabo, A., Chaddock, L., … & Wojcicki, T. R. (2011). Exercise training increases size of hippocampus and improves memory. Proceedings of the National Academy of Sciences, 108(7), 3017-3022.

Gourgouvelis, J., Yielder, P., & Murphy, B. (2017). Exercise promotes neuroplasticity in both healthy and depressed brains: an fMRI pilot study. Neural plasticity, 2017.

Raz, N., Lindenberger, U., Rodrigue, K. M., Kennedy, K. M., Head, D., Williamson, A., … & Acker, J. D. (2005). Regional brain changes in aging healthy adults: general trends, individual differences and modifiers. Cerebral cortex, 15(11), 1676-1689.

Van Dongen, E. V., Kersten, I. H., Wagner, I. C., Morris, R. G., & Fernández, G. (2016). Physical exercise performed four hours after learning improves memory retention and increases hippocampal pattern similarity during retrieval. Current Biology, 26(13), 1722-1727.

Weller, J., & Budson, A. (2018). Current understanding of Alzheimer’s disease diagnosis and treatment. F1000Research7.

Zeidman, P., & Maguire, E. A. (2016). Anterior hippocampus: the anatomy of perception, imagination and episodic memory. Nature Reviews Neuroscience, 17(3), 173.

Memories sparked by music

As I was exploring the Electro exhibition at the Philharmonie de Paris, I was in awe of the transformation of electronic dance music over time. I did not know what to expect when I walked through those doors. Although I have recently been exposed to what goes into making a beat, I was truly amazed at the amount of detail and planning that needs to happen in order to create a harmonious sound. However, I don’t listen to electronic music all that often, and I was shocked at how much I was enjoying the exhibit. I realized that some of my favorite memories have been attached to songs and when I hear them, that rush of emotions comes back. I feel like I am reliving some of the best nights. Music has the power to move me emotionally and helps me remember experiences I wouldn’t always remember otherwise. I am always amazed with how much one song can mean to me, not because of the words but because of what memories are associated with it.

Part of the Electro exhibition

As I was walking through the Electro exhibition, I was reminded of some of my favorite nights listening to my friend make music, and it took me back to a time of such happiness. There have been studies conducted that conclude that music is strongly interconnected with memories (Belfi et al, 2015). In one study, participants heard 30 different songs and saw 30 different faces of famous people. The researchers were looking to measure the strength of memories evoked listening to the songs compared to looking at the faces. They found that the participants had stronger memory association for details and specific autobiographical information when listening to the songs (Belfi et al, 2015).  However, the researchers used a self-evaluation survey to rate the strength of autobiographical memory evoked by each stimulus. This recording strategy may have resulted in a bias or inaccurate association. This study helps us understand that it is possible for music to activate memories with greater specificity. The music in the exhibition had a similar effect on me as well. I was able to remember feeling happy and at peace  while sitting in my friend’s apartment listening to electronic music.

The same feeling of happiness and serenity may be triggered years from now by hearing the same kind of music. This phenomenon could be applied to help patients struggling with Alzheimer’s because music has also been shown to enhance memory in these patients (Cuddy and Duffin, 2005). Researchers wanted to test to see if listening to music helped patients learn and recognize new information (Simmons-Stern, 2010). By pairing unknown lyrics with sung or spoken recordings, the researchers measured which modality was easier to remember for these patients (Simmons-Stern, 2010). They found that after showing the song and the spoken word, the patients with Alzheimer’s disease recognized more words in the sung recordings rather than the spoken word as shown in the figure below (Simmons-Stern, 2010). Healthy patients did not have a preference between modality. To strengthen their conclusion, the researchers made sure to leave out any songs the subjects recognized prior to the study. This study helped demonstrate that there is a possibility of heightening arousal and memory for patients with Alzheimer’s disease through the use of music. Heightened memory may describe why listening to the specific music in the exhibit triggered happiness and peace for me.

The Recognition of Song vs. Spoken Lyric for AD and Control Patients

Stimulation in Electro Exhibit where you could make your own beat

Throughout the Electro exhibition, I was impressed with the way the sound made me feel. Even though I was just listening to the beat, I felt so at home in that space. I was truly impressed with how quickly I was able to transport myself to a different moment. As I walked to the part of the exhibit that let me manipulate instruments to make my own beat, I felt so happy, and I realize now that it’s because the music evoked a memory of my best friend teaching me to do the same thing on his computer. The comfort and happiness of that moment flooded me because the music I was listening triggered an emotional memory.

References:

Belfi AM, Karlan B, Tranel D (2015) Music evokes vivid autobiographical memories. Memory24:979–989.

Cuddy LL, Duffin J (2005) Music, memory, and Alzheimer’s disease: is music recognition spared in dementia, and how can it be assessed? Medical Hypotheses64:229–235.

Simmons-Stern NR, Budson AE, Ally BA (2010) Music as a memory enhancer in patients with Alzheimer’s disease. Neuropsychologia48:3164–3167.

Photo of Study:

Simmons-Stern NR, Budson AE, Ally BA (2010) Music as a memory enhancer in patients with Alzheimer’s disease. Neuropsychologia48:3164–3167.

 

 

 

Fake It till you Learn It

Bonjour! Comment allez-vous? (That’s French for Hi! How are you?) During my first week abroad, there have been so many changes: living with new people, exploring a new city, immersing myself in an unknown culture. Through all these changes, the hardest one to adjust to has been learning a new language that I haven’t heard or seen since the fourth grade. Even though it has been such a short amount of time, I feel that it has gotten easier for me to communicate and understand conversations in French. I came into this trip knowing almost no French, but in just seven days, I notice myself recognizing words at the supermarket, and knowing how to respond to people who speak French fluently. I was actually amazed at how quickly I was able to start learning a new language!

Purchasing food at the local market

Language cognition has been studied to better understand how and where the process of language occurs. There have been new models of language cognition that demonstrate the use procedural memory (long term memory associated with how to do things) and declarative memory (memory of things that can be consciously recalled) in learning a new language (Ullman, 2016). Previous studies have noted that word learning has been a product of our declarative memory, while grammar is heavily dependent on our procedural memory (Davachi et al, 2003, Lum et al, 2012). This process of learning new languages is important, but perhaps not the only thing that has been beneficial during my first week in France.

Although types of memory play an important role in learning new languages, one of the reasons I have been able to grasp French this efficiently is because of gestures and their role in learning language. Gestures are using the body to convey a meaning. Recently, I have been noticing that I have been using my hands a lot more than I usually do while conversing with people. When I see people in the grocery store or the chocolate shops in Belgium, I can communicate with them through the use of gestures to supplement the little French I do know. This helps me learn new words while communicating effectively with people who would not understand me otherwise. Gestures have become a prominent part of my communication method because they are able convey a different type of speech and help me produce speech (Goldin-Meadow and Alibali, 2012).

In an fMRI study done by Weisberg et al (2017), the activation of language regions (shown below) in the brain were reduced when related gestures accompanied speech, as shown in the fMRI data below.

 

Decrease in activation of speech with gesture compared to speech alone and gesture alone

Language regions in the brain

 

 

 

 

 

 

However, when gestures were used alone, there was a greater activation in language comprehension areas. The figure shows that speech accompanied by meaningful gestures does not require as much neuronal resources and thus there is not as much activation in regions associated with action representation or language comprehension (Weisberg et al, 2017). Both of these systems rely on each other to create a more efficient method of communicating using less resources.

There has also been evidence provided that gestures increase the activation of the word they are describing to make it easier for the speaker to access that word (Krauss, 1998). Krauss coined this method as the Lexical Gesture Process Model. In further studies, Krauss found that regardless of spontaneous speech or rehearsed speech, gestures are activated prior or simultaneously to its lexical affiliate, the word the gesture describes. The figure below shows the difference of onset time for speech minus the onset time for gesture and the times are all either happening simultaneously or the gesture is activated before speech. This helps show that the gestures are used as an aid to help communicate in speech because they are activated prior to the words (Krauss, 1998). Thank goodness for these gestures guiding me through these new changes and helping me learn the words!

 

 

I am so lucky to have these gestures as a part of my communication vocabulary because it has made it easier to learn French words and gotten me through the first week. Although I plan on learning more of the language, I am grateful for the grace gestures have given me as I attempt to blend in and communicate with others.

References

  1. Davachi, L., Mitchell, J. P., & Wagner, A. D. (2003, February 18). Multiple routes to memory: Distinct medial temporal lobe processes build item and source memories. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/12578977
  2. Goldin-Meadow, S., & Alibali, M. W. (2013). Gesture’s role in speaking, learning, and creating language. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/22830562
  3. Krauss, R. (1998). Why Do We Gesture When We Speak? Current Directions in Psychological Science,7(2), 54-60. Retrieved from http://www.jstor.org/stable/20182502
  4. Krauss RM, Chen Y, Chawla P. Nonverbal Behavior and Nonverbal Communication: What do Conversational Hand Gestures Tell Us? (2008, April 11). Retrieved from https://www.sciencedirect.com/science/article/pii/S0065260108602415
  5. Lum, J. A., Conti-Ramsden, G., Morgan, A. T., & Ullman, M. T. (2014). Procedural learning deficits in specific language impairment (SLI): a meta-analysis of serial reaction time task performance. Cortex; a journal devoted to the study of the nervous system and behavior51(100), 1–10. doi:10.1016/j.cortex.2013.10.011
  6. Weisberg, J., Hubbard, A. L., & Emmorey, K. (2017). Multimodal integration of spontaneously produced representational co-speech gestures: an fMRI study. Language, cognition and neuroscience32(2), 158–174. doi:10.1080/23273798.2016.1245426

 

Picture of Language Region

  1. https://www.pinterest.com/pin/678847343807021257/?lp=true

 

There’s Nothing Like the Smell of Home

Photo of the metro

About two weeks ago, I arrived very jet-lagged in Paris and couldn’t wait to explore the city. I wanted to take it all in – the sights, the sounds, and the smells. We hit the ground running during our first evening in Paris and rode the metro to the Eiffel Tower. As we waited in the metro station, I realized that I recognized the exact smell of the station. The dusty, metallic smell of the metro brought back many fond and vivid memories during my childhood where I often rode the metro in Toronto. I began to wonder why the smell of the metro brought back such vivid, emotional memories that happened over 10 years ago.

Balls at the museum that emitted smells when you picked them up!

Fast forward to several days ago, I experienced something similar in the Musée du Parfum (perfume museum). It is an amazing museum that is filled with lots of perfume and strong scents that we were able to sniff! One of the scents that stood out to me smelled just like a campfire. Similar to my metro experience, the strong smell of the burning wood brought back many great memories of roasting marshmallows around a bonfire at camp every year.

Fragrant roses at the museum

 

 

In the courses that I’ve taken as an NBB major, I have learned about the separate pathways in the brain that are active during olfaction, memory retrieval, and certain emotional responses. Interestingly, I have not yet learned what happens when those pathways interact like when an emotional memory is retrieved from an odor. I wanted to delve deeper and learn more about what is happening when memories and emotions are retrieved from odors.

Olfactory Pathway Diagram

 

It is already known that olfaction, memory, and emotion are closely linked in the brain. An olfactory signal is transmitted from the primary olfactory cortex to the amygdala and the hippocampus before being sent to higher order olfactory cortices (Shipley and Reyes, 1991). The amygdala is generally associated with emotional responses, while memory processes are closely linked to the hippocampus (Fortin et al., 2004; Cardinal et al., 2002). So, the olfactory signal is relayed through two brain structures that are important for both emotion and memory. 

In 2014, Saive et al. published a study that sought to better understand the interaction between emotion, olfaction, and memory. They tested the hypothesis that emotions invoked by odors facilitate the memory of specific unique events. To do this, they created a model to study memory and mimic real-life situations as best as possible in humans. Participants explored three laboratory episodes, each consisting of three unfamiliar odors (what), positioned at three specific locations (where), within a specific visual environment (which context). Participants explored one episode per day for three days, which they called encoding days. On the 4th day, called retrieval day, they were tested with distractor odors and the odors that they had previously experienced. The distractor odors were used to make sure that participants were associating the correct smells with their memory. Participants were asked to push a button if they recognized the smell, and then had to choose the specific location that they experienced the odor and the correct visual context. They also rated the odors based on pleasantness to investigate the influence of emotion on memory performance.

This study had several important findings that helped researchers better understand what was going on when participants retrieved memories from specific odors. First, they found that the number of accurately remembered contexts and locations was significantly higher when the odors were more pleasant or more unpleasant than neutral. This suggests that the intensity of the emotion  and the distinctness of the smell (but not pleasantness vs. unpleasantness) enhanced memory retrieval. This is what they expected to see – we are more likely to associate a memory that has emotional context with an odor than a neutral smell that we might experience every day.

Measured response times showed that the more information the participants remembered about an episode (what, where, which context), the faster they answered. Interestingly, the time period between odor recognition and retrieving details about their experience was constant no matter how accurate their retrieval was. Since there was no response time difference observed, researchers suggested that after odor recognition participants immediately recalled the whole episode at once rather than in pieces. Put simply, participants didn’t go step-by-step in their memory to recall where there were or how they were feeling, they instead remembered the entire memory at once. This led the researchers to propose a model to explain the cognitive processes that are involved in this unique memory retrieval. This model states that recognizing an odor and retrieving details about the memory associated with the odor are combined into a simultaneous memory retrieval process that begins as soon as an odor is smelled.

One strength of this study is that it mimicked real-life scenarios in the laboratory as naturally as possible by allowing participants to freely explore contexts with unique odors and ranging emotional valences. This makes the model suggested by the researchers more relevant to life outside of the laboratory and helps us better understand how odor is closely tied to memory recognition. Now I understand why I was able to quickly retrieve memories from so long ago just from a smell. Maybe many years from now, the smell of fresh baked bread will bring back fond memories of the many boulangeries (bakeries) I visited during my time in Paris.

Cheers,

Sarah

Bibliography:

Cardinal, R. N., Parkinson, J. A., Hall, J., & Everitt, B. J. (2002). Emotion and motivation: the role of the amygdala, ventral striatum, and prefrontal cortex. Neuroscience & Biobehavioral Reviews26(3), 321-352.

Fortin, N. J., Wright, S. P., & Eichenbaum, H. (2004). Recollection-like memory retrieval in rats is dependent on the hippocampus. Nature431(7005), 188-191.

Saive, A. L., Royet, J. P., Ravel, N., Thévenet, M., Garcia, S., & Plailly, J. (2014). A unique memory process modulated by emotion underpins successful odor recognition and episodic retrieval in humans. Frontiers in behavioral neuroscience8, 1-11.

Shipley, M., & Reyes, P. (1991). Anatomy of the human olfactory bulb and central olfactory pathways. In The human sense of smell (pp. 29-60). Springer Berlin Heidelberg.

Images:

http://www.cbc.ca/news2/interactives/brain/gfx/smell-pathway.jpg – Olfactory pathway diagram

https://pixabay.com/en/train-subway-tunnel-speed-1836126/ – Metro photo, Creative Commons

Photos at the museum – taken by myself

Making Memories One Sniff at a Time

Earlier this week we visited Le Grand Musée du Parfum, or for those of you who don’t speak French, the grand perfume museum (kind of easy to guess). Before arriving, I didn’t know what to expect besides that we would smell a whole lot of perfume. I was right, the building was filled with a variety of fragrances waiting to be sniffed, but this was not the only thing the museum contained. We walked through a maze of rooms displaying all sorts of information about perfume, starting with a historical journey of the origins from ancient Egypt to the Roman Empire and all the way to present time. Following the history was a sensory immersion exhibit (my personal favorite being a neuroscientist) that explained how our sense of smell works and contained olfactory games and fragrant riddles. Lastly, the museum had an exhibit dedicated to the art of the perfumer, where they had a collection of raw materials, natural and synthetic, most commonly used by perfumers. By the end of the museum my odor receptors were exhausted.

smelling one of the perfumer’s raw materials

My favorite room of the museum was the jardin des senteurs, or garden of the scents. We were told to walk up to these large white flowers, close ours eyes, breathe in the odor, try to guess what scent we were smelling and see if it triggered any memories. I did exactly this and took a big whiff of the first odor. Immediately I could recognize the smell of a campfire and a memory was triggered. I pictured myself sitting around a fire with my dad and sister and we were roasting marshmallows, an activity I love to do! I opened my eyes and was surprised and fascinated at the same time by this result. I quickly moved on to the next flower, closed my eyes, and sniffed. I was instantly at my grandma’s house on Christmas morning and an aroma floated through the air. It was cinnamon! I was reminded of the freshly baked cinnamon cookies we made around the holidays.

Jardin des Senteurs (garden of the scents)

Engrossed by this activity, I wondered if different areas of the brain were used when forming and retrieving memories of events in the presence and absence of strong odors. I did some googling and found a recent study that investigated the brain areas involved in episodic memory retrieval, or memories of a specific event, depending on the presence of an odor during encoding, the initial learning of new information (Galliot et al., 2013). Participants in the study consisted of thirteen female students between the ages of 20 and 23 (interestingly no males were used because olfactory abilities and brain regions can differ between genders). The experimental task consisted of two stages. In the first stage (encoding), 32 colored pictures of objects or animals were presented on a computer screen and participants were asked to determine if each picture contained more or less than three colors. This ensured the participants examined each picture carefully, but remained unaware the test was related to memory. During this task participants wore a mask with a valve that contained filter paper soaked in either water or vanillin, an olfactory stimulus usually considered pleasant. Half of the participants wore a mask with vanillin odor for the first 16 pictures and the other half wore the water filtered mask. The participants switched masks for the second 16 pictures.

types of memory

Two weeks later, the second stage (recognition) of the experiment was conducted. During this stage, each of the pictures used in the first stage (target) were presented simultaneously with a new picture (distractor). After the presentation of the two pictures, participants were instructed to press either a left or right button according to the side of the computer screen the participant believed was the target picture. For the duration of this task, participants were in an fMRI machine so that the investigators could record their brain activity. They found brain areas known to be strongly associated with episodic memory retrieval, the posterior hippocampal formations and the anterior thalamic nucleus, were activated whether or not an odor was presented in the first stage. However, they did find that learning in the presence of an odor causes activation of additional brain areas during the retrieval task. One of these areas was the orbitofrontal cortex and it has been previously described as the main site of secondary olfactory processing. They also found other areas in the frontal lobe of the brain, the superior, middle, and inferior frontal gyri (the bumps on the brain), were activated more during presentation of images encoded in the presence of the vanillin odor. However, the specific role in olfaction of these three brain areas remains unclear. I was very fascinated by the results that memories made in the presence of odors activated different brain regions during retrieval.

orbitofrontal cortex

The study also found that there was no significant difference between the number of correct responses of the target images between the pictures encoded with the presence of an odor and the pictures encoded without an odor. This finding made me wonder if the researchers had presented the odor during the retrieval stage of the experiment, would it increase the number of correct responses of the target images encoded with the vanillin odor? When I smelled the campfire and cinnamon odors, my memories were triggered instantly, so I would hypothesize if the participants smelled the vanillin during the recognition task, it would enhance their memory and would increase the number of correct target responses for the pictures encoded with the odor.

Now as I walk through the streets of Paris smelling the freshly baked breads and desserts, I will be reminded that the memories I form will cause different areas of my brain to be activated among retrieval.

Sources:

Galliot E, Comte A, Magnin E, Tatu L, Moulin T, Milot J (2013) Effects of an ambient odor on brain activations during episodic retrieval of objects. Brain Imaging and Behavior 7:213219.

Pictures 1 and 2 were taken by Dr. Kristen Frenzel

Picture 3: http://www.mindauthor.com/psychology/semantic-episodic-memory/

Picture 4:  https://commons.wikimedia.org/wiki/File:MRI_of_orbitofrontal_cortex.jpg

Sugar, Parisian Sights, and Group Runs are Nice

Bonjour family and friends,

When I first arrived in Paris two weeks ago, I was excited to find so many active Parisians running and biking everywhere! Walking around the Cité Universitaire residential campus, I am often startled by a breathless “Pardon!” (Pardon me!) as a runner passes by on my left. Also, more than 20,000 bikes are available for rent in Paris through Vélib’ for €1.70 per day (visit http://en.velib.paris.fr/How-it-works/Bikes). My Paris bucket list definitely includes trading my metro pass for a bike for at least one day in the upcoming three weeks.

Velib

Vélib’ public bicycle sharing system

One of my professors, Dr. Jacob, and our TA, Rachel, lead group runs in parks around Paris. I ran my first half marathon this past March in Atlanta and wanted to continue running and exercising while in Paris. Running is a great opportunity for sightseeing and exploring beautiful, natural spaces such as parks, gardens, and riverbanks.

park run

Rachel and I spreading our wings toward the birdhouse carvings in the tree!

Running also helps work up a healthy appetite…Lucky for me, there’s a boulangerie (bakery) on the corner of each street!

During the hour-long lunch break between my two neuroscience courses, I usually orient myself towards a boulangerie for lunch. Nearly every boulangerie’s Formule Dejeneur (or Lunch Formula) includes a sandwich, drink, and dessert that’s almost too pretty to eat. With so many boulangeries and crêpe stands as far as the eye can see, Paris must be every sugar addict’s heaven on earth. However, such easy access to desserts makes me wonder about the current diabetes rate in France. Also, I wonder in what way physical exercise, such as running and biking, can affect a diabetes patient’s brain. After some online research, I found a few neuroscience explanations to satisfy my curiosities (for now).

Formule Dejeuner

Sample lunch formula

 

Tarte au Citron

Tarte au Citron (Lemon Tart) – Is your mouth watering yet?

First of all, diabetes is a disease in which high blood sugar levels exist over a long period of time. I personally know a few individuals who are pre-diabetic and have to carefully monitor the sugars they consume. Drawing from a research study published today (6/8/2015) in The Lancet, a British medical journal, diabetes occurrence increased 45% from 1990 to 2013 (Global Burden of Disease Study 2013 Collaborators, 2015). In France, 7.2% of adults (20-79 years old) suffer from diabetes. This percentage represented about 3,241,300 diabetes cases last year in 2014 (visit https://www.idf.org/membership/eur/france).

Diabetes, specifically diabetes mellitus, directly relates to neuroscience because this disease decreases brain function and leads to neurodegenerative diseases (Yi, 2015). In a research study hot off the press (5/22/2015), Nunes de Sena et al. investigated the effect of treadmill training on the brain function of diabetic rats. They divided sixty rats into four groups, with exactly fifteen rats in each group.

  • Group one included non-trained, healthy rats.
  • Group two included trained, healthy rats.
  • Group three included non-trained, diabetic rats.
  • Group four included trained, diabetic rats.

Based on this experimental break down, half of the rats received a chemical injection (streptozotocin) that led to diabetes over the course of thirty days and symptoms of hyperglycemia and body weight loss throughout the experiment. After thirty days, the exercise (“trained”) groups underwent five weeks of running training on a treadmill apparatus.

rat on treadmill

Could you imagine seeing this runner training at the gym?

On the day after the last training session, all of the rats participated in a short-term memory test, known as the Novel Object-Recognition Test (NOR). Rats were placed at the center of an open field apparatus (a.k.a. box) and given three minutes to explore their new environment. (This acclimatization period reminds me of the first few days after our arrival in Paris. We also landed in a new environment that we needed to adjust to before beginning coursework.) After the initial three-minute exploration time interval, testing included two five-minute trials. In the first trial (T1), the researchers placed two different objects inside the testing box. In the second trial (T2) one hour later, a new object replaced one of the objects from the first trial. The objects were as different as they could be! They differed in shape, surface, color, contrast, and texture. The researchers recorded the amount of time the rats spent exploring the new object and divided by the amount of time the rats spent exploring both objects, to check for any object preference. In terms of results, both of the exercise groups exhibited a stronger preference for the novel object. Thus, the researchers concluded that treadmill running improved short-term memory performance in both healthy and diabetic rats. I am not entirely convinced, however, based on results from one memory task. In order to establish a stronger connection between running and short-term memory, I think multiple, diverse memory tasks should be carried out. Overall, this paper is significant due to a major strength in the design of the research study: for the first time, researchers used diabetic rats to show that exercise improves performance in a non-spatial memory task. I am highly interested in reading future studies regarding the effects of exercise on other components of brain function in diabetic rats! Hopefully, such studies will contribute to more naturopathic treatments for pre-diabetic and diabetic patients.

With so many picturesque gardens, parks, and the Seine River, Paris provides countless opportunities for running. Even if you have normal blood sugar levels, what are you waiting for? Explore as you run!

À bientôt,

Beatrice

References

Bill F, Foundation MG (2015) Articles Global, regional, and national incidence, prevalence, and years lived with disability for 301 acute and chronic diseases and injuries in 188 countries, 1990 – 2013 : a systematic analysis for the Global Burden of Disease Study 2013. 6736:1990–2013.

De Senna PN, Xavier LL, Bagatini PB, Saur L, Galland F, Zanotto C, Bernardi C, Nardin P, Gonçalves CA, Achaval M (2015) Physical training improves non-spatial memory, locomotor skills and the blood brain barrier in diabetic rats. Brain Res: 1–8 Available at: http://www.ncbi.nlm.nih.gov/pubmed/26032744 [Accessed June 7, 2015].

Yi SS (2015) Effects of exercise on brain functions in diabetic animal models. World J Diabetes 6:583–597 Available at: http://www.ncbi.nlm.nih.gov/pubmed/25987956 [Accessed May 21, 2015].

All images were obtained through a Google image search, besides the image of Rachel and I in the park and the image of the Tarte au Citron.

 

An Ambulance in a Traffic Jam

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.

Going Green–Literally.

Paris is unique in its ability to blend modernity and antiquity. In the heart of Paris, buildings are decades if not centuries old, with intricate designs and rows of windows, all neatly laced in criss-crossing streets and alleyways. It’s a dizzying sight, but one that sparks all of my imaginations and Google searches of the city view. In the peripheral regions of the city are giant skyscrapers, metal behemoths proving that Paris is not just an old city, but still vibrant and thriving well in the 21st century.

Square trees--welcome to Paris?

Amidst all of this man-made wonder, still I feel that something is amiss—greenery. Sure there are parks, and trees carefully planted in rows along the streets, but I can’t help but miss that part of home. I grew up in the suburbs of metro-Atlanta, where trees grew haphazardly and buildings were constructed around them. Nature is one of the reasons for which I am excited to return home–to get my hands messy with dirt and tree sap instead of congesting my lungs with cigarette smoke and exhaust fumes. I guess that’s to be expected in the city, but that is the reason why I would not feel ‘at home’ here. When I do find some odd time, I like to venture into the park across Cite U. It’s huge, with rolling hills, monstrous trees, and a laidback atmosphere with people hoping to escape the hustle and bustle of Paris—if only for a moment.

A map of Parc Montsouris

The freshness of nature is what draws me to the great outdoors. It’s rejuvenating, like taking a nice hot shower on a cold day. I feel connected to Mother Earth, and free of the dusty rooms and buildings that seem to trap more than shelter. Though I have come to appreciate the emotional (and even spiritual) boost I receive when taking nature walks, I began to wonder if there are more tangible benefits to walking in the woods. As luck would have it, research has shown the possibility of improving cognition by surrounding oneself in nature.

Parc Montsouris

A study by Berman et al. focused on understanding how nature can affect individuals with major depressive disorder (MDD) (2012). This disorder affects working memory and is characterized by a constant negative mood.  Nature may help these people improve cognitively, or conversely cause them to ruminate and thus worsen their mood. The researchers used 20 participants diagnosed with MDD. Before starting the nature walks, the participants’ short term memory span and mood were measured using the BDS task and PANAS, respectively. BDS (backward digit span) task involves patients repeating a number auditorily presented each second. PANAS (positive and negative affect schedule) is a questionnaire in which participants rate in terms of intensity a list of emotions (both positive and negative) that they may be feeling. Lastly, the participants were asked to ruminate on a negative event in their life, to see if nature walks would alleviate or aggravate the ruminations.

A park near the Bastille, on an archway above the busy streets below

Participants walked on a designated path for about 50 minutes (2.8 miles) in either a secluded park or traffic-heavy downtown area. Upon returning, they again completed the BDS task and PANAS. The researchers also asked the patients what they thought about during their walks, to roughly see if ruminations persisted on the walk. The experiment was repeated a week later, with the participants walking along the path they had not walked in the first session. Results show that the participants had relatively similar BDS score before the tests, but those in the nature walk had higher scores (i.e. a larger memory capacity) than those in the city walk. In terms of mood, the participants scored higher on more positive emotions and lower on negative emotions after the nature walk than after the urban walk. Lastly, participants in either walk ruminated on the negative event to the relatively same degree.

Garden in the Chateau de Villandry

Garden in the Chateau de Villandry

These results of the study are interesting because they suggest that perhaps one can improve memory and mood simply through walking through nature. Even though the ruminations didn’t differ during either walk, still the participants demonstrated better short term memory and mood, indicating that just avoiding those negative thoughts is not why they scored higher on the tests. Maybe environment does play a stronger role in our cognition than previously thought.

Still, I was curious to learn more about the root of cognitive improvement through these nature walks. After some research, I found data that blew my mind. A study investigated the role of a bacteria, Mycobacterium vaccae in mice behavior and learning (Matthews and Jenks, 2013). These bacteria are found in soil, water, and plants, i.e. the basic ingredients of a nature walk. Previous research has studied the symbiotic (both parties benefiting) relationship between microbes and animal hosts, and the possible brain-gut connection through these animals improve cognitive abilities after ingesting the bacteria.

Lopsided tree, perfect for climbing

Skipping the gory details, mice were tested for anxiety-related behaviors and speed of completion of maze navigation. Those fed the bacteria had reduced anxiety-related behaviors and completed the maze twice as quickly as mice not given the bacteria. The level of activity did not differ between the experimental and control mice, since both groups used the running wheel a similar amount of time. The results are astonishing because they show that by simply ingesting certain bacteria, mice can improve learning and reduce their anxiety.

If we can somehow test this in humans, and ascertain to what degree the Mycobacterium vaccae bacteria exist in our environment and our bodies, maybe we can come to similar conclusions. These data could potentially show that walking in nature does not only give a psychological boost—we may be actually replenishing our stock of that bacteria, becoming cognitively stronger without even realizing it. Though we may be far from truly understanding this effect in humans, I will take these results as a cue to continue my nature walks. If not for the healthy boost of bacteria, at least I can leave the crowded, polluted city for fresh air, green trees, and a glimpse of untouched beauty.

-Mayur Patel

Relaxing on a giant branch

Relaxing on a giant branch

References:

Berman M, Kross E, Krpan K, Askren M, Burson A, Deldin P, Kaplan S, Sherdell L, Gotlib I, Jonides J (2012) Interacting with nature improves cognition and affect for individuals with depression. Journal of Affective Disorders 140: 300-305

Matthews D, Jenks S (2013) Ingestion of Mycobacterium vaccae decreases anxiety-related behavior and improves learning in mice. Behavioral Processes 96: 27-35

The Broken Escalator Effect (It’s Real)

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.

Want to Remember Paris? Take a Nap!

Since arriving in Paris I have immersed myself in a lesser-known aspect of French culture – Naps. 

While not as famous as the country’s delicious food and fine wine, the French nap, particularly when enjoyed on the banks of the Seine River or on a bus ride through Loire Valley, is a key part of the French lifestyle. In fact, napping is so important to the French that recently their minister of health, Xavier Betrand proposed that they schedule Spanish-esque siestas into the normal workday to increase napping-opportunities. He even suggested that these siestas count as paid work hours!

So, with much determination, I have subjected myself to a grueling routine of daily naps, often conveniently located at some of Paris’s most beautiful landmarks. But unfortunately this napping regime takes time, and since I’m not receiving health minister Betrand’s proposed nap-time monetary reimbursement, I needed to do some research to see if my dedication to the French culture was worth the time away from my neuroscience studies.

It turns out that napping could very well be helping my academics! There have actually been many research studies that show significant increases in ability of individuals to remember facts when they take a brief nap after learning new information. 

So what is a nap?

View of the Seine from behind Notre Dame. Location of a wonderful nap in the sun.

In order to understand the research behind nap-improved memory, it’s important first that we briefly define different sleep stages, and the different types of naps associated with each.

Non-Rapid Eye Movement Sleep (NREM): NREM sleep is comprised of 4 stages. Stage N1 is the drowsy period right at the onset of sleep. N1 is often associated with body twitches and the ability to still be somewhat aware of your surroundings. The second stage, N2, is when your muscles relax and you lose all awareness of your surroundings. This stage occupies about 40% of total sleep time. The final two stages of NREM, N3 and N4, are the deepest sleep stages and are often termed slow-wave-sleep because of their distinct shape when recorded on a electrocephologram (a machine used to measure electrical activity in the brain).

Rapid Eye Movement Sleep (REM): As the name suggest this sleep is often accompanied by rapid eye movements. Additionally, when you wake yourself up by kicking or swinging your arm it most likely occurred during REM sleep.

Long Naps: Naps that last longer than 40 minutes. Includes all stages of NREM and REM sleep. Because long naps include deep sleep phases, they are often associated with sleep inertia upon waking (the groggy-feeling where it’s difficult to get fully awake).

Short Naps: Naps between 10-40 minutes. Commonly called “power naps,” these naps normally just include stages N1 and N2, however they can include N3 if approaching 40 minutes in length. 

Ultra Short Naps: These are naps as short as 5 minutes and normally are just stage N1.

The science behind the French-nap 

Students napping on a bus ride to Loire Valley

Since sleeping between class or on a bench amongst the hubbub of tourists and street vendors doesn’t lend itself well to long naps, the majority of my sleep has been limited to 6-40 minute intervals. Interestingly, there was a study recently published in the Jounral of Sleep Research that looked at this exact length of nap and it’s effect on the ability of 18 college-age individuals to remember a list of words (Lahl et al., 2008).

The study was pretty simple, each student was given a list of thirty adjectives and told to memorize as many of them as possible. At the end of two minutes the lists were taken away and the students were broken up into 3 sleep-groups. One group was allowed to sleep for 5 minutes, another for an average of 35 minutes, and a third was not allowed to sleep at all. After 60 minutes, each student was asked to repeat the adjectives they could recall from the list. The number they remembered was recorded and averaged with the other’s in their sleep-group. This experiment was done twice more with the same students, once a week after the first test, and then again another week later. To make sure the experiment was accurate they used different word lists each time and also rotated which group slept for 6 min, 35 min, or not at all. By the end of the experiment each student had been in each sleep-group once.

The results of this experiment are great news for the French-nap! It turns out that those who took a short nap were able to remember on average 1.2 more words than those who didn’t sleep at all and students who took long naps where able to remember an average of 2.2 more words than their non-sleeping peers. While 1-2 words might not seam like a huge difference, it is considered statistically significant because of the small number of total words in each list (30 words). Also, many other sleep-memory experiments have shown similar results thus helping to confirm the data from this study (Tucker et al., 2006).

Some additional experiments have been done to show exactly how this memory-improvement occurs. When you sleep, your brain doesn’t “shut-down” like many people believe; instead parts of the brain ramp up their activity. One of these areas, the hippocampus, has been shown to be a key part of the memory-forming networks in the brain (Gorfine et al., 2007). Increasing the activity of the hippocampus during sleep is a way for our brains to rehearse the events we recently experienced, thus strengthening the connections between neurons that solidify those memories in our brain. Short bursts of sleep, such as my French-naps, are thought to specifically help in the formation of factual memories. Additional research has shown that another part of the brain, the orbitofrontalcortex, might help the hippocampus in the formation and storage of these memories (Lesburgures et al., 2011). However, this research is very recent and the connection between sleeping and its effect on the orbitofrontalcortex needs to be studied in future experiments. Until then, I’m happy to know that I now have a scientifically proven excuse to nap across Paris – I’m activating my hippocampus and helping store all of the material learned in class that day. Next stop, a nap beneath the Eiffel tower!

– Camden MacDowell

On of my many ultra short naps in the ACCENT center where we have our classes. My hippocampus is hard at work.

Works Cited

Gorfine T, Yeshurun Y, Zisapel N (2007) Nap and melatonin-induced changes in hippocampal activation and their role in verbal memory consolidation. Journal Pineal Research 43: 336-342.

Lahl O, Pietrowsky P, Wispel C, Willigens B (2008) An ultra short episode of sleep is sufficient to promote declarative memory performance. Journal of Sleep Research 17: 3-10.

Lesburgures E, Alaux-Cantin O, Bontempi B, Gobbo A, Hambucken A, Trifilieff P (2011) Early tagging of cortical networks is required for the formation of enduring associative memory. Science 331, 924-928.

Tucker M., Chaklader A, Fishbein W, Hirota Y, Lau H, Warnseley E (2006) A daytime nap containing solely non-REM sleep enhances declarative but not procedural memory. Neurobiology of Learning and Memory 86: 241-247