Category Archives: Uncategorized

Move to the Music

Last week I had the pleasure to watch people expressively jump, fall, run, and spin, all to the beat of music. Where could I see this moving art in the city of lights? The Palais Garnier hosts variety of shows including opera, concert, and, in my case, a ballet. As a person who can’t walk across a flat surface without tripping, I was amazed to see the unfathomable poise the dancers had in their movement. They could perfectly match complex poses and key beats of the music with a grace unfounded in the dancing my friends and I did in the Latin District discotheques. Nevertheless, over the next week I discovered whether you have the grace of a ballerina, a mosh pit, or an audience member during Fête de la Musique, all of our brains possess circuitry that enables our bodies to “move to the music.”

Four photos from the performance I attended: Bertaud / Bouché / Paul / Valastro at Palais Garnier. Taken from https://www.operadeparis.fr/en/season-16-17/ballet/bertaud-bouche-paul-valastro.

What came first: dance or music? A popular hypothesis addressing this “chicken or the egg” question promotes dance preceded music as dance is an application of motoric abilities essential for survival in most animals (Dean, Byron, and Bailes 2009). However, as music promotes reproductive success and enrichment of cultural capital, the two probably had a mutual factor encouraging their coevolution: rhythm. Rhythm perception has been consistently traced to brain areas such as the premotor and supplementary motor areas and the basal ganglia. Damage to these areas has caused timing issues (Grahn and Brett 2007). For instance, patients that have Parkinson’s Disease, a disorder affecting the basal ganglia, struggle with walking at a rhythmic pace (Grahn and Brett 2007).

Taken from http://antranik.org/wp-content/uploads/2011/11/basal-ganglia-caudate-nucleus-and-putamen-and-thalamus-and-tail-of-caudate-nucleus.jpg

Supplementary Motor Area. Taken from https://static1.squarespace.com/static/52ec8c1ae4b047ccc14d6f29/t/576f2964b3db2bd35f648444/1490438406965/supplementary-motor-area.jpg

Recent research has better elucidated how our bodies perceive and synchronously move with different rhythms. A typical lab test for rhythm involves tapping alongside a beat that may fluctuate in speed. A 2016 study used this set up as participants sat in a dMRI, an MRI imaging machine that specifically tracks water movement in your brain. dMRI is a useful technique for visualizing the highways that carry information across your brain, called white matter tracts. The goal of the study was to investigate what “highways” are used most when syncing movements to a beat. During the task, they averaged the asynchrony between the beat and the participant’s tapping as well as how long it took the participant to adjust when the beat became faster or slower. The imaging system tracked increased water flow to particular brain regions, thus implying more activity along that highway when conducting the task.

Typical DTI image showing tracts of brain that send information to other brain areas. Taken from https://www.healthcare.siemens.nl/magnetic-resonance-imaging/options-and-upgrades/clinical-applications/syngo-resolve.

The study found syncing movements to the beat lead to more activity in the frontal area of the left arcuate fasiculus (Blecher, Tal, and Ben-Sachar 2015). As the arcuate fasiculus is an important connection highway between your main auditory perception area and premotor areas, it is no wonder stronger connections between these two areas promote better synchronization. In the context of the ballerinas at Palais Garnier, strong connections along the arcuate fasiculus are necessary for performing jumps and plies on the beat.

Correlational image of left arcuate fasiculus activation with mean asynchrony (Blecher, Tal, and Ben-Sachar 2015).

Arcuate Fasiculus. Taken from https://clinicalgate.com/wp-content/uploads/2015/03/B9780702037382000322_f032-001-9780702037382.jpg

The study also suggests people who are consistently better staying on beat have more activation along their temporal callosal segment(Blecher, Tal, and Ben-Sachar 2015). Callosal segments are highways known to connect the right and left sides of your brain. If we were to image a ballet dancer’s brain to mine, we would likely find stronger connections along the temporal callosal segment in the graceful ballerina than the clumsy college student. But what happens when the music becomes faster mid-performance? In this case, the study suggests our brains adjust to the new time via activation of the precentral callosal segment, another right-left brain highway by the motor regions of the brain (Blecher, Tal, and Ben-Sachar 2015). Overall, this research paper concluded highways on your left side of the brain connecting your auditory and motor areas and particularly activated when predicting and comparing auditory inputs and motor commands. Additionally, they concluded motor and premotor highways, which join the left and right side of brain, particularly activates when adjusting to a beat change(Blecher, Tal, and Ben-Sachar 2015).

dMRI image of participants brain. Precentral callosal segment shown in pink along side graph reflecting correlation between activation of segment with resynchronization time. (Blecher, Tal, and Ben-Sachar 2015).

Precentral gyrus where the pre central callosal segment connects the two hemispheres of the brain. Taken from https://www.kenhub.com/en/atlas/gyrus-precentralis

While this paper explains how we perceive and adjust to music beat, I would love to see more studies that particularly investigated rhythm changes in music. Jazz, for example, has a swing rhythm that doesn’t necessarily stay to one beat pace the whole song. I am curious if some music is easier to sync to your movements to than others. While I am pretty good at dancing on beat to a typical pop song, other genres of music like heavy metal may be more difficult to dance to because of the rhythmic beat inherent to the genre. Future experiments could possibly compare listeners with artists who specifically play that genre as well as artists who play a separate genre of music. I would expect artists of that genre would have stronger brain activation among rhythm-perception pathways when listening to their own music compared to artists who play a different genre or an average listener. Future experiments such as that one may better elucidate my understanding of why humans enjoy coordinating our bodies alongside a great song.

 

Bibliography

Blecher T, Tal I, Ben-Sachar M (2015). White matter microstructural properties correlate with sensorimotor synchronization abilities. NeuroImage 138:1-12

Grahn JA and Brett M (2007) Rhythm and beat perception in motor areas of the brain. Journ Cog Neurosci 19 (5): 893-906

Dean RT, Byron T, Bailes FR (2009). The pulse of symmetry: On the possible co-evolution of rhythm in music and dance. Musicae Scientiae 341-367.

Metro Madness

It was a typical Monday morning as I left Cité Universitaire, the complex where our dorms are located, and headed to the Accent building where our classes take place. I leave everyone morning at 9am to give myself an hour to travel and have extra time to stop by my favorite Parisian coffee shop, Starbucks (only place that gives American sized portions). As I was walking to the metro station, I ran into my friend, Swetha, and we began talking about our presentation later that day. Once we got to the metro station, the RER B had just arrived, so we quickly scanned our passes and hopped onto the last car of the train, which was overcrowded with passengers. This was typical in the mornings for a train to be packed like sardines in a can. We continued to talk as the train left the station.

Parisians have a difficult time spelling Chandler

A few minutes later we arrived at the next metro stop and the doors opened. Swetha and I were standing next to the door and could tell some passengers were trying to move to get off at this station, so we stepped outside of the train car to make it easier for people to leave. One-by-one passengers were exiting the car and I was getting excited because this meant we would have more personal space to stand and possibly even get a seat! But then we realized all of the people in our car were getting off, which seemed unusual. Confused by this, Swetha and I looked towards the front of the RER B and noticed that it wasn’t only our car, but all of the passengers from the entire train were exiting.

RER B metro stops map

Swetha looked at me with a puzzled look and we decided to follow the mass of the people even though this was not the station we wanted to get off at. Did we miss an announcement (not that I would understand because I don’t speak French) that the RER B was closing? We quickly thought of an alternative route to get to class. We would ride line 6 for a few stops and then transfer to line 8 to get to our final destination, the Bastille station. We followed the signs towards line 6, but somehow this led us outside of the metro station! Confused by how this happened, we decided to follow the sign that had an arrow pointing to the left hoping this would lead us to the front of the metro station.

Swetha is confused

After walking for a couple minutes we realized the sign misled us (not the first time this has happened to me while in Paris). We were headed away from the metro station. We stopped and looked around to see if we had any clue of where we were, but nothing seemed familiar. At this point, our sense of direction was completely lost. But then I spotted the restaurant we had eaten dinner at the night before, which served delicious crepes, and I knew exactly how to get back to the entrance of the metro station. We used our memory of the path we took from the restaurant and successfully made it back to the metro station. We quickly headed towards line 6 hoping we would be able to make it to class on time and as we were walking a RER B train pulled up. Now we were really confused but quickly decided to hop on and go back to using our normal route to class. We came to the conclusion it was only our original train that was closing for the day because it let us off at an unfamiliar spot, hence why we were led outside of the station. After this eventful journey, we were finally back on track to class and we even made it in enough time for me to buy a much-needed coffee.

 

The restaurant we ate at for dinner

My experience of getting lost made me wonder about human’s sense of direction. Previous courses I have taken have taught me about the various ways animals can navigate, but most of these don’t apply to humans. Some animals use magnetoreception for navigation, in which they are sensitive to the earth’s magnetic fields. Other animals use orientation of the sun or orientation of the night sky by looking at the position of the sun or patterns of stars to navigate. One last way animals navigate is by learning specific landmarks in an environment. This is how I was able to navigate to the metro station, by using the restaurant as a landmark.

Birds use magnetoreception for navigation

In order for an organism to be able to navigate in the world, it must know where it is and what direction it is facing. Previous studies have found a group of cells in the brain that respond to the location information of an organism and when the organism turns, the activation of the cells also rotates to the equivalent amount of movement the organism made (Knierim et al. 1995). These cells make up a neural compass. In order for the neural compass to be useful, the organism must have a heading, or a defined direction, relative to fixed features of the environment. This is similar to how a magnetic compass’s heading is defined relative to the north-south axis of the earth. An example of a heading for the neural compass would be the use of a landmark to anchor the organism’s sense of direction.

A study was previously performed by a group of researchers, and they looked for the brain region that is involved in using a local landmark as a heading for the neural compass and hypothesized that it is essential for use of a landmark to be able to retrieve memories about the environment (Marchette et al. 2014). To test these ideas, the researchers collected fMRI data (looking at areas of the brain activated during a task) while participants imagined themselves in a newly learned virtual environment and performed a judgment of relative direction (JRD) task (which I will explain in a moment).

The researchers created a virtual environment that consisted of a square park containing four rectangular buildings, or museums. The museums were identical in shape and size, but were distinguishable by the building design of textures and architectural features, such as columns. Surrounding the park were environmental features, such as a mountain range or forest, which made each side different. The inside of the museums were identical in the number of rooms and room size, but were decorated differently. Each museum contained 8 distinct nameable objects, and each of the objects could only be viewed from one specific direction in a room. Participants were given a training period to learn the layout of the virtual environment in which they explored the park freely for 15 minutes and then performed a guided learning tour in which the name of an object appeared on the screen and the participant had to navigate to find the location of the object. Participants navigated using arrow keys.

Images of the inside and outside design of the museums in the virtual environment

After participants were trained on the environment, they had to perform the JRD task. During this task, the names of a reference object and a target object were presented visually and simultaneously in gray letters on two different lines at the center of a black screen (for example, “Facing the Bicycle”, “Lamp”). Subjects were instructed to imagine themselves standing in front of and directly facing the reference object while they made a judgment about whether the target object from the training environment would be located to their left or right. This required them to imagine themselves in a specific location while facing a specific direction, which means that they must mentally reorient themselves (re-establish their sense of direction). Researches collected fMRI scans of participants while they performed this task.

After looking at the fMRI scans, the researchers found the retrosplenial complex (RSC), a region in the brain, was activated during the JRD task. They determined the RSC represents imagined facing direction and imagined location during memory retrieval of a place. The researchers discovered this happens by using a reference frame that is anchored to local environmental features and they found this task is generalized across the different museums/local environments with similar geometric structures. These findings suggest that the RSC is centrally involved in a critical component of navigation through environments by establishing one’s position and orientation relative to fixed elements of the external world.

Image from the study showing the location of the RSC

A strength of this study was the performance of an additional task to verify that their findings about the RSC were due to activation of the brain from scenes and not due to the objects in the museum. They tested this by showing participants images of objects, scrambled objects, and scenes while performing a fMRI scan and found that the RSC responded significantly greater to the scenes than to the presentation of the objects or scrambled objects. While the study described results about using a reference frame (an object inside the museum), to make judgments about the location of another object in a museum, I would have liked to see the use of bigger, immobile structures as a reference frame. In the real world, and not the virtual environment, the reference objects could be moved and this would cause the location of a heading to orient a person’s sense of direction to be obstructed. If they had used the mountain range or a building as the reference for navigation, this would have related more to how humans use a landmark as a heading.

Although this study was performed in a virtual environment, it gave me insight about how humans navigate based on specific references. Next time I get lost in Paris, I will know which area of my brain is being used as I try to find a landmark to establish my position and orientation in order to be able to recall how to get to a metro station.

Sources:

Knierim JJ, Kudrimoti HS, McNaughton BL (1995) Place cells, head direction cells, and the learning of landmark stability. J. Neuroscience 15:1648–1659

Marchette SA, Vass LK, Epstein JR, Epstein RA (2014) Anchoring the neural compass: coding of local spatial reference frames in human medial parietal lobe. Nature Neuroscience 17:1598-1606

Pictures 1-4 were taken by myself

Pictures 5-6 are from creative commons

Pictures 7-8 are images from Marchette et al. research paper

Reading the Mind Through the Eyes

As a small group traveling together through the metro for after-class adventures, we flock. Not knowing where we’re going, we the students of the Emory NBB Paris Program look to our mother ducks, Dr. Frenzel and Rachel, for guidance.

Footage of us getting off the metro.

As a duckling, I’ve noticed that our mothers are very good at nonverbal communication. They seem to be able to tell each other things with incredibly vague gestures and odd facial expressions without using any words. We, the ducklings, do not understand their communicative abilities, but I think it could be something unique to being a real adult.

The ability to convey so much information through facial expression alone is incredible. Unspoken communication is even more evident between people who don’t speak the same language. These nonverbal cues are common in Paris between native English speakers and native French speakers. I’ve encountered many exchanges in which participants attempt to use spoken language, but gestures and facial expressions end up being more effective. One study suggested that transient facial expressions cannot be consciously recognized but can be perceived at the unconscious level (Xiao et al., 2016). We can recognize emotions through facial expressions but aren’t aware of it, which is probably the reason why we often get a vibe or a feeling about a person even if we can’t think of what it was that caused us to make that impression. Even if we can’t put a finger on the exact cue, we are able to synthesize the information and use it to make decisions. Well why do some people like our mother ducks pick up on each other’s cues so much easier and seem to have almost telepathic communication?

The Eyes Test is a measure of cognitive empathy.

A recent study has suggested a genetic basis for the ability to read a person’s thoughts and emotions from simply looking at their eyes (Warrier et al., 2017). A test to measure “cognitive empathy” called the Eyes Test has previously shown that some of us are better at this than others, and specifically that women score slightly better than men (Baron-Cohen et al., 2001). The newest study used genetic data from 89,000 people across the world along with the online Eyes Test and confirmed that women tend to do better on the test than men. Interestingly, higher scores on the Eyes Test also correlated with larger volumes of the caudate nucleus and the putamen, which together form the dorsal striatum, a part of the brain which may play a role in cognitive empathy (Abu-Akel and Shamay-Tsoory, 2011). Analysis of genetic data revealed that women’s ability to “read the mind in the eyes” is associated with variations on

The striatum is part of the basal ganglia and may play a role in cognitive empathy.

chromosome 3, whereas this ability in men is not related to this particular region on chromosome 3 (Warrier et al., 2017). But what makes this part of chromosome 3 special? It turns out that it’s really close to a gene called LRRN1 (Leucine Rich Neural 1), which is highly expressed in the striatum. Essentially, women who demonstrate higher cognitive empathy have larger dorsal striata, which may be due to variations in specific genes.

Our moms working together to make chocolate.

So what does this mean in terms of the abilities of our mother ducks to communicate with one another while guiding our flock around Paris? It means they probably have a leg up already on Dr. Cafferty at reading each other’s minds because they are women, and they may even have special variations in chromosome 3 that have led to their increased cognitive empathy abilities.

While all of this is pretty cool, it’s important to note that the variations and correlations in this study were only marginal, meaning that there are probably many other mechanisms involved in cognitive empathy. This study doesn’t fully explain differences in “mind reading” skills, but it opens up a door to continue researching the genetic basis of cognitive empathy to better understand disorders, such as autism, associated with deficits in social skills.

 

References

Abu-Akel A, Shamay-Tsoory S (2011) Neuroanatomical and neurochemical bases of theory of mind. Neuropsychologia 49:2971-2984.

Baron-Cohen S, Wheelwright S, Hill J, Raste Y, Plumb I (2001) The “Reading the Mind in the Eyes” Test revised version: a study with normal adults, and adults with Asperger syndrome or high-functioning autism. J Child Psychol Psychiatry 42:241-251.

Warrier V, Grasby KL, Uzefovsky F, Toro R, Smith P, Chakrabarti B, Khadake J, Mawbey-Adamson E, Litterman N, Hottenga JJ, Lubke G, Boomsma DI, Martin NG, Hatemi PK, Medland SE, Hinds DA, Bourgeron T, Baron-Cohen S (2017) Genome-wide meta-analysis of cognitive empathy: heritability, and correlates with sex, neuropsychiatric conditions and cognition. Mol Psychiatry.

Xiao R, Li X, Li L, Wang Y (2016) Can We Distinguish Emotions from Faces? Investigation of Implicit and Explicit Processes of Peak Facial Expressions. Front Psychol 7:1330.

https://upload.wikimedia.org/wikipedia/commons/e/e7/Ducks_army_marching.jpg

https://c1.staticflickr.com/6/5171/5495036012_1a6eda966c_b.jpg

https://upload.wikimedia.org/wikipedia/commons/thumb/d/de/Dopamine_pathways.svg/800px-Dopamine_pathways.svg.png

Our Brains Want Chocolate…Literally

Salut mes amis!

I have literally been waiting since the beginning of this trip for this one day. I’ll give you some clues: It’s sweet. It’s yummy. There’s a golden ticket involved. Do you know it yet? Willy Wonka’s chocolate factory!!!! Okay maybe not that exact one, but I’d say this comes as a close second. Just walking in immersed me in an air of chocolatey yumminess, and this was just the entrance with the gift shop. The excitement was literally killing me.

Le Musée Gourmand du Chocolat

Future Chocolatiers

 

I think I may just switch careers and become an Oompa Loompa. I mean chocolatier, or do I? Besides, I don’t see why not. I’ve already got my partner, Kara, and I got to say I think we make a pretty good team. With our piping, tapping, and scraping skills, I think we’ve got a solid business. So, if my whole neuroscience plan doesn’t work out, well you know where to find me.

 

Getting our blessings from the real master 🙂

Well, back to the chocolate making. First, we got to learn how to make the first layer of our molds with some creamy dark chocolate. By the way, they sort of looked like mini Patrick Star’s from SpongeBob. Anyways, after 15 minutes in the freezer, we added some hazelnut and milk chocolate as our center layer and set it back in the fridge. We topped it off with some more dark chocolate and voila! We had created a masterpiece! Très délicieux! Obviously, we weren’t professionals so it was unfortunate that we made quite a bit of an artistic mess on the table. So, to make up for our “accidental” spills, we were forced to clean it up by eating it all. It was tough, but we had to do what was right. I mean, we were simply following in the footsteps of our role models.

Our moms have become the kids…

As we made our way around the museum, I started to think about how chocolate affects our daily lives. Before every exam I have had since high school, I make sure to get some chocolate in my system. Even just a little Hershey kiss. It became a psychological thing for me, but it turns out, chocolate might have some neurological effects on us.

Making our mark everywhere we go!

Chocolate contains cocoa flavanols, which are antioxidants and anti-inflammatory agents with known benefits to our cardiovascular health. These chemicals seem to accumulate in the hippocampus, a region that is involved in memory and learning. It is believed that these chemicals interact with various signaling pathways in our brain that help process long-term memories (Sokolov, 2013).

The hippocampus plays a role in processing short-term memory to long-term memory

In a recent study, Mastroiacovo et al. (2014) looks at the effects of chocolate on cognitive function. They recruited 90 elderly individuals who were assigned to consume a drink containing cocoa flavanol every day for 8 weeks. This drink, somewhat like chocolate milk, contained either high, intermediate, or low flavanol concentrations and their cognitive function was assessed using various mental examinations at the beginning and end of the 8-week period. There was improvement seen in all three groups, and more significantly in the high and intermediate groups. This may be an effect of cocoa flavanols increasing the blood flow in the brain. This is important because our blood transports nutrients and fuel to our body, and by increasing its flow, we are able to deliver more “brain food”. Aside from neurological benefits, they also saw a decrease in blood pressure, cholesterol and insulin levels (Mastroiacovo, 2014). All the more reason to consume chocolate, right?

Since this study was done in elderly individuals, I would really like to see if the impact of chocolate would be greater if this type of routine were done throughout childhood. It would definitely give us kids more reason to go chocolate crazy. They also looked at other health improvements (e.g. blood pressure) in addition to cognition, which will encourage investigation of other physiological effects caused by chocolate. 

Presenting chocolate Patrick Stars

 

 

Moral of the story in my opinion: Never say no to chocolate! What’s the worst it can do, make you smarter?

 

 

 

À bientot!

Swetha Rajagopalan

Bibliography

Crichton, G. E., Elias, M. F., & Alkerwi, A. (2016). Chocolate intake is associated with better cognitive function: The Maine-Syracuse Longitudinal Study. Appetite,100, 126-132. doi:10.1016/j.appet.2016.02.010

Mastroiacovo, D., Kwik-Uribe, C., Grassi, D., Necozione, S., Raffaele, A., Pistacchio, L., . . . Desideri, G. (2014). Cocoa flavanol consumption improves cognitive function, blood pressure control, and metabolic profile in elderly subjects: the Cocoa, Cognition, and Aging (CoCoA) Study–a randomized controlled trial. American Journal of Clinical Nutrition,101(3), 538-548. doi:10.3945/ajcn.114.092189

Sokolov, A. N., Pavlova, M. A., Klosterhalfen, S., & Enck, P. (2013). Chocolate and the brain: Neurobiological impact of cocoa flavanols on cognition and behavior. Neuroscience & Biobehavioral Reviews,37(10), 2445-2453. doi:10.1016/j.neubiorev.2013.06.013

Images Retrieved from these sites:

 https://tl.wikipedia.org/wiki/Hippocampus

Love on the Brain in Paris

One of the first things that come to mind when I think of Paris is love.

Ever since I was young, I looked forward to a time in my life where I would meet someone who I connected with on a deep emotional level and who I could experience the rest of my life with by my side, someone who at the end of my life we can together look back on all the memories we made and happiness we shared with one another.

Mur des Je t’aime: The wall of love

Paris can be otherwise referred to as the city of love and ever since my arrival, I can see why. Not only do people show more physical affection when in public, but also the surrounding scenery bodes for romance. With the Pont des Arts Bridge filled with lovelocks to the romantic language spoken throughout to the Mur des Je t’aime otherwise referred to as the wall of love with 311 different languages to say I love you, love and romance permeates throughout this city.

Pont des Arts Bridge with lovelocks

After walking through the park on my way back from brunch, I could not help but notice the amount of couples so deeply focused on one-another and so clearly in love. This public affection of love seems to be a lot more common here than I am used to and led me to want to research more about the effect love has on the brain.

Being in love appears to directly affect structures and circuitry in the brain. I have previously heard of the effect of love being equated with that of a drug due to its influence on specific body hormones and the reward system in the brain.   I decided to find a study that looked at a different impact love has on the brain. The study I found looked at the gray matter in the striatum of the brain, so the cell bodies in a portion of the front of the brain, as well as, perceived subjective happiness (Kawamichi et al, 2016). The researchers divided the individuals into two groups based on whether they were in a romantic relationship or not. They used an imaging technique, as well as, a subjective happiness scale and found that those in a romantic relationship had reduced cell bodies in an area in the front of the brain and increased subjective happiness. In essence, those in love feel happier and have perceived happier or more positive experiences.

Visual/Graph from Paper. The visual shows the location where they see difference in gray matter in the dorsal location of the Striatum. The graph shows the significant difference between the gray matter for those in a relationship (less gray matter) vs. no relationship.

To me this was very interesting to read about. Being in love affects our brain structures, so that we feel happier and perceive experiences as more positive. Walking around Paris and seeing the couples so enthralled and focused on one another, it makes sense that love affects the chemistry of the brain on a deeper level. I can see why Paris is the city of love. From the glistening Eiffel Tower at night to the beautiful architecture on all the buildings unlike I’ve ever seen before to the Chateaux’s we visited, the environment is magical, making it a perfect place to be known for love.

A Chateaux we visited

Bibliography

Kawamichi, H., Sugawara, S. K., Hamano, Y. H., Makita, K., Matsunaga, M., Tanabe, H. C., . . . Sadato, N. (2016). Being in a Romantic Relationship Is Associated with Reduced Gray Matter Density in Striatum and Increased Subjective Happiness. Frontiers in Psychology, 7. doi:10.3389/fpsyg.2016.01763

All images not my own from Creative Commons

 

 

 

 

Beyond the Help of Google Maps

If you travel with me long enough, you’ll find out I’m amazing at U-turns. This random talent has been continually cultivated by my terrible sense of direction, a condition that, whether walking, driving, or exploring, is beyond the help of Google Maps. Naturally, I was wary of coming to Europe out of anxiety of getting lost. Sure enough, during this Paris program and my cliché Euro-backpacking trip, getting lost down strange streets and roads was inevitable. However, all things considered I’ve been impressed how easily I can navigate my way to class or tourist attractions. I’ve even found myself guiding my friends when going to particular destinations. What about Europe makes my sense of direction sharper? This question motivated my investigation into the neurobiological pathways that modulate spatial navigation.

Taken from http://favim.com/road+sign/.

In the 1970’s a groundbreaking discovery in rats started detailed neurobiology research on how we know where we are. Neurons in the hippocampus and parahippocampus (brain location shown below) increase their firing rates when rats moves through specific regions of their environment, therefore creating a mental map (Ekstrom et al., 2003).

Taken from http://www.bristol.ac.uk/synaptic/pathways/

Figure from Ekstrom et al. (2003) showing images from the virtual reality participants navigated

Human experiments have found that neurons known as parahippocampal place cells fire when recognizing landmarks and passively exploring environments (Maguire, Burgess, and O’Keefe, 1999). Many navigational studies of recent decades image brains via fMRI or record neuron firings while participants move in virtual environments. For example, in a 2003 study participants drove a virtual taxi, picking up and dropping off customers at various locations around the virtual town. Both brain regions possessed “goal cells” that fired more if the participant succeeded in one of the experiment’s tasks. They found the hippocampus primarily activated to specific spatial locations while the parahippocampus fired when viewing a landmarks (Ekstrom et al., 2003). Tourism centers obviously understand the importance of landmark recognition when getting around, as most maps for Paris contain pronounced images of popular landmarks beside the street name. Our dependence on landmarks, however, can vary. One review referenced a study stating women rely more on landmarks than men as men also incorporate more global views into their mental maps (Maguire, Burgess, and O’Keefe, 1999).

Map of Paris with landmarks emphasized. Taken from http://parismap360.com/paris-tourist-map#.WT241KtLlSU

What does this navigational model mean when I’m trying to find the Eiffel Tower? My parahippocampus registers coarse spatial features, such as the metro station sign or the Eiffel Tower itself, while my hippocampus combines contextual visual and spatial features to form a mental map. Should I make the trek back to that location the next day with my friends, the same cells that encoded those features will fire again, reinforcing my overall sense of direction.

Taken from https://www.linkparis.com/paris-metro-map.htm

As I discussed my improved sense of direction with a friend, she posited that maybe this change was simply due to increased attention to my surroundings. A 2004 paper particularly backed her claim. Spatial tasks with mice found that long term firing stability of parahippocampal place cells was significantly increased with enhanced attention and context relevance (Kentros et al., 2004). Attention’s influences on navigation probably modulate neuron firing by promoting long term information encoding instead of short-term storage. Therefore, because I’m motivated to get back to my dormitory after exploring, I pay more attention, which in turn encodes landmarks along my walking route as memory traces. According to this mouse model, several hours can go by and I can still make it back to Cité Universitaire without getting lost.

In contrast to this idea, a human experiment published this year found innate sense of direction is unaffected by conscious attention (Burte and Montello, 2017). Participants who had various levels of self-assessed sense of direction navigated an unfamiliar neighborhood under a condition of intentional attention or incidental learning. The results found intentional attention participants did not learn the route any better than those of incidental learning, concluding sense of direction is applied without internal application. However, this study recognized their experimental design did not exactly follow models of other human studies that have promoted attention modulation when navigating.

While enhanced attention is a likely candidate for my newly gained sense of direction, more research is necessary before I have a sound explanation. In the meantime, however, I plan to enjoy exploring Paris with my friends using faster routes and, hopefully, fewer U-turns.

NBB 2017 Summer Program at the Eiffel Tower!

 

 

Bibliography:

Burte H, Montello DR (2017) How sense-of-direction and learning intentionality relate to spatial knowledge acquisition in the environment. Cog. Research: Principles and Implications 2:18.

Ekstrom AD, Kahana MJ, Caplan JB, Fields TA, Isham EA, Newman EL, Itzhak F (2003) Cellular networks underlying human navigation. Nature 425:184-187.

Kentros CG, Agnihotri NT, Streater S, Hawkins RD, Kandel ER (2004) Increased attention to spatial context increases both place field stability and spatial memory. Cell 42:283-295.

Maguire EA, Burgess N, O’Keefe J (1999) Human spatial navigation: cognitive maps, sexual dimorphism, and neural substrates. Current Opinion in Neurobiology 9:2:171-177.

When You Smile to the World, the World Smiles Back

I have been in Paris for two weeks now, and I am still marveling at the sights and beauty of this new world around me. For anyone who doesn’t know, this is actually my first time out of America, so I have never really experienced culture shock like I have here in Paris. There are so many differences I have noticed, from restaurants only giving room temperature tap water to drink for free, to having to pay for bags in the grocery store, to the language barrier I deal with everyday.

If you know me, you know I am ALWAYS smiling. No matter what I’m doing, or who I’m talking to, 99% of the time I have a huge smile on my face. When I first got to France, we were staying at the Ibis Hotel near the Accent Study Abroad center in the heart of Paris.

As my friends and I were roaming the area, I kept making awkward eye contact with the French people walking, and I noticed something super strange: NONE OF THEM SMILED. It’s regular for me to make eye contact with someone, and even if I do not know them, I smile because where I’m from, that is the polite thing to do. However, I smiled at each and every one of these people, and each of them stared back at me with a blank expression. I honestly thought it was so rude. I immediately turned to my friends and said, “Did you guys notice that nobody here smiles? Isn’t that like human nature to smile at people? French people are so rude.” Even my friends thought that smiling at strangers was just the way the world worked, and even they were confused by this lack of expression from the Parisians. Once I got home, I googled “Why don’t French people smile?” (also if you know me, you know I google absolutely everything). I found a very interesting blog post about how that is just a major cultural difference between Americans and the French. Apparently, French people reserve their smiles for people they actually know. In fact, that actually find it strange when strangers smile at them, and they think it means they are making fun of them (Paridis 2013).

A photo I took walking down the street. Normally, it is pretty normal for people to not smile when they are just walking, but I made eye contact with two people after this photo and smiled, and neither of them smiled back.

After reading this blog, I began wondering how these cultural differences came about. I started questioning if it was actually weird that Americans just smile at people we don’t even know, or are we just extremely friendly people? As a personal preference, I love smiling. I don’t understand why anyone would not want to smile at people whether they know them or not. Smiling is a universal sign of kindness, so why not share it with the world?

As I was searching this subject (on google of course), I came across a neuroscience research article that proved that smiling can affect the way our brains process other peoples’ emotions (Sel et al., 2015). The study, interestingly enough, was conducted in France in 2015. There were 25 right-handed men and women with normal vision who participated in this study. For the experiment, each participant was shown a set of 90 pictures depicting happy and neutral emotions. In two separate blocks, they asked participants to adopt either a happy or a neutral facial expression during a judgment task of the emotional intensity of the images presented. Previous research shows that intentionally putting on an emotional facial expression is directly correlated with increased activity in the emotional brain network (Kuhn et al., 2011). The participants were also receiving an EEG (a test to detect electrical activity in your brain) while they were performing the judgment task. An N170 is a component of the EEG that shows the neural processing of faces. Literature suggests that the N170/vertex positive potential (VPP) complex is the brain activity shown when people are observing others’ facial features.

Fig. 1 (A) Experimental manipulations: self-neutral block, participants were asked to maintain a neutral expression and relax their face; self-happy block, participants were instructed to hold a happy expression by biting on a pen horizontally with the teeth. Control manipulation: self-control block, participants were asked to purse their lips in order to hold a pen with their lips only. (B) Timeline of the stimuli presentation. (Sel, 2015)

By performing the experiment this way, researchers were able to determine the effect of the participants emotional expression on the brain mechanisms underlying visual processing for the observed facial expressions. If the face processing was independent of the participants emotional expression, then the VEPs (visual evoked potential; brain activity caused by a visual signal which is seen on the EEG) of observing other’s happy and neutral faces wouldn’t be affected by their own facial expressions.

However, as the researchers hypothesized, the results showed that the participants’ facial expression of happiness significantly altered the N170/VPP of when they observed other neutral faces compared to when they observed the neutral face while also having their own neutral expression (evidenced in the difference between the red and green lines in figure 2A below). The results suggest that when people are smiling, they actually observe other neutral faces similarly to the way they view a happy face.

Fig. 2 (A) Grand average VEPs when observing happy faces (green: self-happy condition; red: self-neutral condition) and neutral faces (blue: self-happy condition; black: self-neutral condition). (B) Selected electrodes included in the ANOVA (Sel, 2015)

The results support the hypothesis that intentionally adopting a certain facial expression can change the subjective feelings corresponding to that emotion, which then influences perception of other’s facial expressions. They show for the first time that a person’s happy expression acts as an influence on visual processing, modulating neural activity when one observes neutral faces as compared with happy faces.

One strength of this study is that after the study, they went back and added another control to further validate their conclusions. Based on the way the study was conducted, it can be argued that the effects of self-happy expression on visual processing of others’ facial emotions could just be based on the contraction of facial muscles in general, rather than specifically smiling. To rule out this possibility, the researchers added a control in which the participants had to clench their mouths in a way that prevents smiling, but still contracts facial muscles. The results of the control were the same as they were for the self-neutral expression, which further proves that the effects shown in the VEPs to neutral faces are specific to the participants smile. This reassures that there is a direct contribution of one’s own facial expression of happiness to the way that person visually processes others’ faces.

A weakness I found in this study is that when choosing participants, it is not stated if they ruled out people with certain mood disorders, such as bipolar disorder or manic depression, that could automatically influence how they perceived the others’ emotional expressions. I think that going forward, it would be interesting to specifically test how the effect of smiling can work in people with mood disorders.

As for me, I am completely happy with the results of the experiment. It just goes to show that really, if you smile at the world, the world will smile back at you (at least you will perceive it that way).

Until next time,

Keep on smiling!

-Janet

References:

Kuhn S, Muller BC, Van Der Leij A, Dijksterhuis A, Brass M, Van Baaren RB (2011) Neural correlates of emotional synchrony. Social Cognitive and Affective Neuroscience 6: 368–74.

Paradis V (2013). Don’t Smile!. French Truly. Web.

Sel A, Calvo-Merino B, Tuettenberg S, Forster B (2015) When you smile, the world smiles at you: ERP evidence for self-expression effects on face processing. Social Cognitive and Affective Neuroscience 10.10: 1316-322.

 

Have you been scammed, yet?

Bonjour!

Many of you may know that Paris is a hub for street scams. From the typical “bracelet scam” to the shell game scam is found at every tourist spot in Paris. Let me back up a little and explain what this particular scam entails. There is a ball under one of the three cups in front of you. The challenge is to point out the cup under which the ball is after the dealer has shuffled them around.

The participant puts in foot on the cup and pays the dealer 100 euros

Although it seems oddly “easy” to identify the right cup, this game is a trap for tourists who are unaware of the scam. To make the tourist even more susceptible, the dealer has a group of people around him pretending to be participants, when in reality they are all in on the scam. These people bet money and win double of what they bet, they clap and encourage vulnerable tourist to bet money, and most importantly, they tell you that you are “obviously” going to win if you pick that specific cup. But guess what? No one wins- because its all just a fraud that many people fall for, their first time visiting Paris.

Video 1

It was my second day in Paris, when I went to the Eiffel tower with a couple of my friends. Soon after we got off the metro, we saw a crowd gathered around. We peaked through and saw this game being played. At first sight, my impression was “ofcource it’s a scam,” but when I watched it for a couple of minutes and saw people actually winning money, I was intrigued to believe that winning is an actual possibility. Although I didn’t bet any money, my friend was willing to just go for it and I also supported that idea. It was obvious that she was right, the ball should have been under that cup because we saw it with our own eyes! The dealer picked up the cup, and to our surprise, the ball was not there. We freaked out and felt vulnerable. She wanted the money back so she bet money again, and this time we were surer that the ball is under the cup she picked; however, just like the previous time, she lost the money. We couldn’t fathom how he did that, how he made the ball disappear but there was more to that game than what met the eye. After my friend researched the trick behind this game, we went back to the Eiffel tower to comprehend what really happened. This time, knowing the trick, it wasn’t very difficult for me to understand what was happening. The dealer picked up the ball in a subtle manner while he shuffled the cups around, so no matter which cup you picked you were going to lose your money.

I was really mad and tried to spoil his game by telling people its scam. Interestingly, one of the “pretend players” comes up to me and tells me that I should keep my mouth shut and leave if I didn’t want to play.

This whole incident got me thinking, why do people fall for this scam? Why do we take such risks despite the possibility of adverse consequences? My curious neuroscience side wanted to see how the brain is involved in such behavior. A study called, “Individual differences in susceptibility to investment fraud” by Knutson and Samanez-Larkin (2014) investigated susceptibility to investment fraud via the differences in physiological, neural, and behavioral data between victims and non-victims of investment frauds. They hypothesized that (1) victims will show increased preference for risky gambles (increased activity in Nucleus Accumbens or decreased insula activity); (2) victims will show reduced behavioral control especially when incentives are high (decreased ventrolateral prefrontal cortical activity). They assessed the first hypothesis using the gambling task. In this task, victims and non-victims, in each trial, viewed a gamble cue, waited as the wheel spun, observed and reported the outcome (selecting “gain” or “loss” presented randomly on either side of the screen), and saw trial and cumulative earnings. Basically, they were assessing if victims prefer low probability but high magnitude risks compared to non-victims.

Gambling task

They found that victims showed no preference to the type of gamble but non-victims preferred positive skewed (low probability of a high gain) over negative skewed (low probability of a large loss) gamble. To test their second hypothesis, the participants took the Monetary Incentive Delay Inhibition task. In this task, they were presented with incentives and tested on their ability to control impulses.

Monetary Incentive Delay Inhibition task

The behavioral results show victims failed to inhibit their responses when the gain was larger compared to non-victims. The neural results show decreased activity in the right ventrolateral
 prefrontal cortex of victims than in non-victims when considering negative skewed gambles (exp. 1) or when anticipating larger gains (exp. 2).

This data shows that fraud victims lose impulse control when they see the potential of a large gain. If the possibility of gaining is low, but the magnitude is high (like double the money in the shell game scenario), some people are willing to take the risk because they are prone to riskier gambles and lack impulse control when the gain is large. Even though this study does a good job explaining differences in vulnerability amongst people, it fails to explain if this individual difference can be explained by predisposition or significant differences in brain structure. They mention the role of nucleus Accumbens and anterior insula in their hypothesis but fail to mention these brain areas in any results or conclusions they drew. Although more research need to be done to explain the actual causation of differences in risky behavior in humans, this study demonstrates a strong correlation between decreased activity in the ventrolateral prefrontal cort
ex and victim to investment fraud, which relates to my observation that some people fail to inhibit their impulses when the reward is large.

Watch out for those scams, fellas.

Until next time, Au revoir!

 

References

Knutson B, Samanez-Larkin G (2014) Individual Differences in Susceptibility to Investment Fraud. Research on Fraud.

Image 1 and video 1 taken by me.

Image 2 and 5: Creative commons

Image 3: Wu CC, Bossaerts P,  Knutson B (2011) The affective impact of financial skewness on neural activity and choice. PloS one 6(2):e16838.

Image 4: https://www.researchgate.net/profile/Gang_Chen34/publication/221781705/figure/fig2/AS:267537376084038@1440797289961/Figure-1-Modified-monetary-incentive-delay-MID-task-Each-trial-began-with.png

 

 

 

Monkey See, Monkey Do

Thinking back to fifth grade field trips, the long lines, the sweltering hot Louisiana sun, and the teachers who thought that the visit would be the pinnacle of fifth grade achievement, I became accustomed to disliking trips to public places like zoos, museums, aquariums, etc. That being said, I never would have imagined finding myself paying 16.50 euros to go to a zoo here in Paris—yet there I was last Saturday, in that very position. Little did I know that that trip would become one of the most memorable ones of my first week in Paris.

Photo Courtesy of Google Maps

 

Parc Zoologique Sign

 

It all started when I met Bruce, a zebra in the zoo who I decided to name myself. There I was–staring at two especially unexciting rhinos and wondering to myself whether there were any animals in this zoo that did anything other than sleep through the day–when, as if on cue, Bruce appeared out the brush and proceeded to feast on a nearby tuft of grass. He was almost close enough to touch, the intricate patterning of his dust-covered black and white stripes catching my eye. Never in my young adult life would I think that I would be so excited to see a zebra, but there I was, gasping and aweing with the eight-year olds beside me.

Bruce and I

 

Bruce wasn’t the only new friend I made that Saturday afternoon. I had yet to see my favorite exhibit—the baboons. As I approached, the first thing I noticed was the large number of people watching from the viewing platforms. This must be a good one, I thought to myself. As I peered through the enclosure, I was surprised by their cacophonous action. There was always some baboon doing something hilarious somewhere in the cage—one chewing on some type of plastic, another swinging from tree to tree, yet another sitting up straight—quite peculiarly with its hands folded in its lap and looking like an old-time English professor.

 

The English Professor

However, I quite literally believe I got stars in my eyes when I caught sight of a newborn baboon with its mother. The baby—I named him Johnny—climbed on its mother’s back for a piggyback ride to the watering hole. When they arrived, Mom sat down, whipped Johnny around to her front side (her back to the viewing platform) and began breastfeeding. Soon enough, two other mothers arrived and started breastfeeding their babies, until there was a ring of nurturing mothers and their children. I was struck by the similarities in these baboons to human mothers—the way they cradled their children, the way they stroked their newborn’s fur as the baby suckled, the protective sidling of the mother whenever a male encroached into her area—with every minute I watched, I could see why these were our closest animal relatives.

Mothering Baboons

 

Being the budding neuroscientist that I am, I started to consider the brain mechanisms for this behavior. In almost every animal species, mothers innately care for their young—this obviously makes sense in an evolutionary perspective, but what are the brain mechanisms for this behavior? What motivates it? What is the neuroscience behind it all?

An article by Kikuchi et al. (2015) addresses the neuroscience of maternal love. The experiment was designed to look at the brain activity of young mothers when viewing video clips of their 16 month old infants showing attachment behaviors. Mothers in an fMRI were shown either a clip of their infant smiling at them while they played together (play situation—PS) or of their infant being in distress when the mother left the room (separation situation—SS). The researchers hypothesized that the parts of the brain mediating maternal behavior would be more activated when the infant was in distress (SS) than when the infant was not (PS). After the fMRI, mothers were asked to rate their subjective feelings (happy, motherly, joyful, warm, love, calm, excited, anxious, irritated, worry, and pity) in response to video clips in PS/SS of their own infants and of other infants.

So, what did the researchers find? There were four brain regions found to be specifically involved in feelings of motherly love: the right orbitofrontal cortex (OFC), the anterior insula, the periaqueductal gray (PAG), and the striatum. After identifying these brain regions, researchers then had to interpret what these results actually meant. Essentially, the OFC and the striatum are involved in the dopamine reward system, which would involve the mother’s motivation to care for her infant. The OFC, insula, and PAG are involved in an information processing system mediating homeostatic emotions for the mother and the realization of motherhood itself. Since the OFC is involved in both systems, it is thought to play an important role in mediating between the two.

Activated regions from Kikuchi et al.

Schematic of brain activation from Kikuchi et al.

 

After all was said and done, researchers found that mothers did, indeed experience higher brain activation in SS than in PS. As subjective ratings of worry increased in the SS, activity in the right OFC increased. Good to know that mom cares.

What’s great about this article is that it provides a simple and straightforward model of measuring brain activation of mothers in response to their babies. It asks the mothers’ subjective feelings in addition to the neurological aspects. However, it can also be said that this method might be too straightforward—mothers are undoubtedly faced with more than two situations of maternal love and attachment. Perhaps in the future, the authors could consider approaching a more complicated model—one with more situations like a feeding or a stress situation. Also, it is definitely a challenge to quantify love in a scientific aspect as these article attempts to do—perhaps it might be too poetic for such a field.

Poetic or not, there is an undeniable beauty in the way a mother cares for her child—whether that mother is human, baboon, or zebra. Either way you look at it, Johnny the baboon is certainly well accounted for.

 

-Ngozi

 

Yoshiaki Kikuchi et al. (2015) The Neuroscience of Maternal Love. Neurosci Common 2015; 1: e991. doi: 10.14800/nc.991.

Photos taken by yours truly.

 

 

Not Being Able to Smell Really Stinks !

Bonjour, tout le monde! I’m having a wonderful time in Paris. Classes have been in session for almost two weeks now, and my classmates and I are having a great time learning both in and out of the classroom. This afternoon, for example, we visited Le Grand Musée du Parfum (The Grand Perfume Museum).

Front entrance of the museum

Rachel and Alicia smelling some fancy perfumes!

This museum does a wonderful job at explaining the intricacies of all things perfume! On the ground floor we were welcomed with audio guides in English. They were a huge plus because my French knowledge is very elementary. The basement floor had multiple rooms that explained the history of perfume. From medicinal qualities, like 17th century plague doctors using aromatic vinegars to protect themselves against contagions, to ceremonial scents, like ancient Egyptians bathing Cleopatra with sacred oil blends in 1st century BC, this floor had countless historical stories about perfume. The top floor is dedicated to the art of the perfumer. It contains multiple rooms that play video loops of perfumers explaining their artistic vision and how they’re inspired to create new perfumes every day.

Ground level of the museum

The remaining floor is all about sensory immersion. There are several little tests visitors can take to understand the role of olfaction in their day-to-day lives. Interactive “Fragrance Games” as well as a “Sensory Garden” make this floor both entertaining and enjoyable for most. Sadly, I was not very entertained. I wasn’t able to participate in the interactive games, and I didn’t enjoy this floor as much as the others. This is because I have hyposmia.

Hyposmia is a condition that means you can’t detect odors as well as the average person. It’s a milder form of anosmia, or inability to smell. When I was 17 years old, I was in an accident that left me with a fractured skull and a severe traumatic brain injury, or TBI. I’m totally fine now, four years later, except I still have a hard time smelling the world around me. Wondering how a TBI could possibly affect someone’s ability to smell? Let me explain.

Here’s a simplified explanation of olfaction. Your olfactory bulb, the main part of your brain responsible for processing odors, is located at the bottom part of the frontal lobe of your brain. It has many connections to higher brain areas to process smells and associate them with memories and emotions. Your nasal cavity has a mucous membrane that contains odor receptors on olfactory neurons that travel through a bone in your skull called the cribriform plate to communicate with your olfactory bulb.

In a head injury, a “coup” occurs at the site of the impact with the object. So, as shown in the picture, if someone hits the front of their head hard enough against a wall, their brain will suffer from a coup injury at the front of their brain. A “countrecoup” injury occurs at the site opposite the impact. So, in the same example, the person would experience a “countrecoup” injury at the back of their brain. This rough, abrupt movement causes the cribriform plate to sever some or all olfactory neurons, depending on the severity of the impact. This movement breaks the connection to the olfactory bulb, causing anosmia. My neurologist first described the process to me as a cribriform plate being sort of a like a cheese grater with olfactory neurons threaded through it. He told me that when my accident happened, my cribriform plate shredded my olfactory neurons like cheese. Yum! Before leaving the hospital with this delicious yet sad image, my doctor gave me a bit of hope. He told me that olfactory neurons are one of the only ones in the human body that have the natural capability to regenerate! Despite my wishful thinking, it has been four years now since my injury, and I have very little to no perception of smell. So I have to wonder: is it really true? Will I really be able to smell again someday? I did a little PubMed searching, and here’s what I found.

Researchers at Boston University recently did some research to learn more about regenerated olfactory neurons and their ability to function properly. Previous studies have shown that olfactory neurons do, in fact, have the ability to grow back, or regenerate (Schwob, 2002). The more important aspect of regaining smell, though, is where these neurons reconnect to the olfactory bulb.

If neurons don’t reconnect to the right areas of the brain after damage, then your perception of what you’re smelling would be off. The receptors from your nasal cavity have to link up with the exact area of your brain to tell you what you’re smelling. This process is kind of like an operator making sure an incoming call is directed to the right person. You don’t want to be connected to your Aunt Beth if you’re really trying to call your best friend. Similarly, if you smell something like chocolate, that neuron needs to connect to the area in your brain responsible for perceiving the smell of chocolate.

Dr. Cheung and his colleagues recently conducted a study to find out whether or not regenerated olfactory neurons are able to connect to their corresponding area of the brain. In order to do this, they used mice whose olfactory bulbs glow when activated. This allowed researchers to map where in the brain new olfactory neurons reconnected to after damage. They used an odor that is toxic to olfactory neurons to damage one side of the brain of the mice. Then, after a period of time for the mice to recover from the damage, images were taken of their brains after exposure to different odors. These images allowed for researchers to see where the neurons that regenerated during the recovery period connected to the brain.

They found that when comparing the unaffected hemisphere of the brain and the recovered one, similar areas of the olfactory bulb were activated in response to multiple odors. This means that when neurons in the damaged hemisphere regenerated, they were able to connect to their respective areas of the olfactory bulb. However, they also found that more significant damage limits the renewing ability of olfactory nerves. Severely damaging the olfactory neurons and the nasal tissue they originate in caused scarring of this tissue. Because of this, there was almost no activation in the damaged hemisphere in response to odorants even after a full recovery period. This means that in severely damaged brains, not only did regenerated neurons not find their way back to their targeted areas of the olfactory bulb, most of them didn’t regenerate at all (Cheung et al., 2014).

My new friends helped me pick out a new perfume!

I really appreciated the way this study was conducted. Instead of being satisfied with their results in the first part of their study, Cheung and his colleagues went one step further to see if severe damage would have a greater effect on neuron pathway restoration. I would like to have seen them try a method of physically damaging the neurons, like severing them, in one group as well as chemically damaging them. I wonder if the physical damage would produce results that are more similar to the severely damaged group.

So, would the damage to my olfactory neurons from my TBI be classified as severe? Will my olfactory neurons ever regenerate and find their rightful place connected to my olfactory bulb? Or is the only reason I can detect smell even a little bit due to only a few of my olfactory neurons regenerating? Unfortunately, I can’t answer any of these questions with one hundred percent certainty. Hopefully further research in this area will help me with these answers. Until then, I guess I’ll just stick to visually interactive museums instead of smelly ones and continue to let my friends help me pick out perfume.

Despite not being able to participate in the fun games on the first floor, I had a really great time at Le Grand Musée du Parfum! If you’re ever in Paris, you should totally visit.

Le Grand Musée du Parfum’s location in Paris

References:

Cheung MC, Jang W, Schwob JE, Wachowiak M (2014) Functional recovery of odor representations in regenerated sensory inputs to the olfactory bulb. Frontiers in Neural Circuits. 7: 1-16.

Schwob JE (2002) Neural regeneration and the peripheral olfactory system. Anat. Rec. 269: 33-49.

Pictures from the museum were taken by myself.

Pictures illustrating coup/countercoup injuries and the olfactory bulb were taken from Creative Commons.

Map section was taken from GoogleMaps.