Tag Archives: Sleep

Rodents on My Mind, Rodents on the Metro

What does this look like to you?

The RATP logo (Image from Creads.fr)

To me it looks like a female face tilted back to take a big whiff of something—presumably, the fresh, pleasant-smelling air of Paris’s underground metro system (of course I’m being entirely facetious; it is often quite the opposite).

Why is this relevant? Let me explain.

One day on the way to class, out of boredom I was perusing the exciting advertisements plastering the walls of the metro car. My eyes landed upon this intriguing logo, accompanied by the letters, “RATP,” and I found it to be one of the most unintentionally amusing things that I have ever seen.

Standard interpretation of the RATP symbolism (Image from Creads.fr)

You see, in class we have been discussing many experiments that use mice. Mice are really good at being the subjects of neuroscience experiments, it turns out. So the first thing that came to my mind was this sort of double entendre: this poster was advertising the Paris metro system while highlighting the scent of rat urine that may often accompany it.

Lab rat (Image from Shutterstock.com)

The symbol and acronym actually represent Régie Autonome des Transports Parisiens, the group that operates much of the public transportation in the region. And according to one website, the logo is supposed to be an artistic representation of  Paris.  I never would have guessed this, but perhaps my interpretation is unique, influenced by my recent experiences in class.

In fact, I’ve been thinking so much about rodents that I’ve been dreaming about them! So I wanted to know: Why was I dreaming about mice? Is it possible that these dreams impacted my interpretation of the RATP symbol?
My theory was that mice have been so prevalent in my thoughts during the day (due to all the neuroscience research that I have been reading about) that they infiltrated my dreams at night. Maybe this is what led me to interpret the logo in such a humorous way! Neuroscience can provide some answers as to what likely occurred here.

The neuroscience of sleep and dreaming isn’t fully understood. But, scientists know that the brain isn’t inactive when we’re asleep: contrary to the idea of “resting” during sleep, the brain actually doesn’t shut down at all (Debunking Sleep)! It fluctuates through different stages of activity  throughout the night, meaning the cells are active in different patterns (Brain Basics).

During one type of brain activity called slow-wave sleep (SWS), our brains “replay” certain memories from the day and put them into long-term storage (Hasselmo, 1999). This is termed “memory consolidation,” and it is as if these experiences were being packaged into neat little containers for protection and easy access in the future. During “slow-wave sleep,” cells are sending signals in slow bursts, and this likely had a role in making my memory of the mice stronger and easier to recall! This strong memory of mice seems to be why I interpreted the RATP symbol in such a way. But what does dreaming have to do with it?
Dreams are created by the brain’s activity while we sleep. Scientists also know that their content—the scenes and emotions that get incorporated into them–is pulled from our recent thoughts and experiences while we’re awake (Stickgold et al., 2001). This explains why I was dreaming about mice!

But, my question isn’t fully answered yet: Was dreaming about mice what caused the memory consolidation that led to my humorous interpretation?

Neuroscientists actually don’t yet understand the relationship between dreaming and memory consolidation. But, some current research can help to shed some light on the subject.

A recent study by Siclari et al. (2017) identified a certain part of the brain they called a “hot spot” for dreaming. Whenever a certain type of activity is detected in this area—the back half of the brain, lying directly behind your ears—you are likely dreaming!

In order to do this, researchers used a machine called an electroencephalogram (EEG) to measure people’s brain activity while they were sleeping. Using sensors placed all over each subject’s head, this machine detects changes in electrical activity, telling researchers the patterns in which brain cells are firing (Britton et al., 2016).

Electroencephalogram (Image from Michigan Advanced Neurology Center)

In this study, people wearing EEG sensors (shown in the picture above) were awakened at random points during a night’s sleep and asked to report if they had been dreaming. By looking at the EEG data, the researchers were able to determine that high frequency activity—meaning that brain cells were sending signals very quickly—was associated with dreaming when it occurred in the back half of the brain. This means that they were able to predict whether someone was having a dream or not (Siclari et al., 2017)!

So what does that mean for me? The conclusions of this study suggest that dreams are actually less likely to occur during SWS, which is associated with low-frequency activity. Since this activity signals when memory consolidation occurs, it is not clear if dreaming about mice helped my brain consolidate the memory.

Dreams of neuroscience experiments (Image from ScienceABC.com)

But, it’s still not clear if dreams have a role in consolidating memories. In the realm of neuroscience research, these findings are important, but they don’t exactly align with what has been suggested in the past. Some researchers have found that dreaming about an experience enhances one’s ability to recall it (Fiss et al., 1977; De Koninck et al., 1990; Wamsley 2014). Still, this is an essential step in understanding the mechanisms of memory consolidation in sleep: dreams likely have some functions that we haven’t fully uncovered yet!

In conclusion, it is still amusing to me how my daily experiences—solidified into my memory during sleep—shaped my interpretation of this advertisement in such an entertaining way! Certainly my experiences in class contributed a lot about rodents to my memory bank, and I’m grateful for it: If nothing else, it gives me an extra opportunity to chuckle to myself every day on an otherwise monotonous metro ride!


Brain Basics: Understanding Sleep. (n.d.). Retrieved from https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Understanding-Sleep

Britton J.W., Frey L.C., Hopp J.L., et al. (2016). Electroencephalography (EEG): An Introductory Text and Atlas of Normal and Abnormal Findings in Adults, Children, and Infants. American Epilepsy Society. Available from: https://www.ncbi.nlm.nih.gov/books/NBK390346/

De Koninck, J., Christ, G., Hébert, G., Rinfret, N. (1990) Language learning efficiency, dreams and REM sleep. Psychiatr J Univ Ott. 15:91-92.


Debunking Sleep Myths: Does Your Brain Shut Down When You Sleep? (n.d.). Retrieved from https://www.sleepfoundation.org/articles/debunking-sleep-myths-does-your-brain-shut-down-when-you-sleep.


Fiss H, Kremer E, Litchman J. (1977).The mnemonic function of dreaming. Sleep Res. 6:122

Hasselmo, M. E. (1999) Trends Cogn. Sci. 3:351-359.pmid:10461198

Que signifie le logo RATP ? Creads décrypte ! Design Tribe. 06 May 2019. 17 June 2019 <https://www.creads.fr/blog/logos/ratp-logo-signification>.

Siclari, F., Baird, B., Perogamvros, L., Bernardi, G., LaRocque, J. J., Riedner, B., … Tononi, G. (2017). The neural correlates of dreaming. Nature neuroscience, 20(6), 872–878. doi:10.1038/nn.4545.

Wamsley, E.J. (2014) Dreaming and offline memory consolidation. Curr Neurol Neurosci Rep.14:433. doi:10.1007/s11910-013-0433-5.








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Café au Lait to get Through the Day

My amazing “café au lait” from Coutume Café in the 7ème arrondissement


Who doesn’t love a nice, hot cup of coffee after a morning shower? Not only does it taste AMAZING, but it also wakes you up and gets you ready for the day to come. Every morning, for the last 4 or so years, I drink a cup of coffee while getting dressed or eating breakfast. So, upon coming to Paris, I undoubtedly continued my ritual.

The walk from Cité Universitaire (where I live) to Coutume Café (my favorite coffee shop).




I essentially used my love of coffee as an excuse to visit as many cafés and small restaurants as possible. However, I soon discovered the enormous difference between French coffee and the American coffee that I am used to. The French are huge advocates for espresso, that is, a coffee-like drink served in tiny porcelain cups. However, unlike American coffee, espresso is extremely potent and filled with a TON of caffeine. Over the past few weeks, I too have become a lover of espresso and the large amount of caffeine and “energy” that comes with it. However, I was not quite sure exactly how caffeine affects the brain resulting in what we perceive as a boost in energy and decrease in drowsiness. So, throughout my days in Paris, I looked for an answer.

Typical French coffee (left) vs. typical American coffee (right)

While searching for an answer, I stumbled upon an article by Lazarus et al. (2011) concerning the effects of caffeine on wakefulness. Previous research found that caffeine counteracts fatigue by binding to adenosine A2A receptors. Adenosine, an inhibitory neuromodulator, has been linked to regulation of the homeostatic sleep drive. So, by binding to the receptor in the brain that normally binds to adenosine, caffeine indirectly prevents adenosine from functioning properly, altering one’s sleep pattern (Huang et al., 2011). Lazarus et al. used this information to construct their experimentations.

In their study, Lazarus et al. bred a strain of rats that had a knockout of the A2A receptor in their nucleus accumbens, that is, these rats did not have this receptor within this specific brain region. They then performed EEG (electrical monitoring) tests on these rats and compared their electrical brain activity with that of control rats (rats that did not have the A2A knockout). The researchers administered equivalent concentrations of caffeine to both groups of rats and monitored their brain’s electrical activity during sleep cycles. What they found was extremely interesting. The caffeine caused increased wakefulness in the control rats (those that did not have the A2A receptor knockout), while caffeine had no effect on wakefulness in the experimental rats (those with the A2A receptor knockout). This means caffeine not only blocks adenosine from binding to the A2A receptor (Huang et al., 2011), but it also prevents the activation of the “adenosine break,” resulting in increased wakefulness.

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A figure from Lazarus et al. (2011) depicting the adenosine A2A receptors in the nucleus accumbens of rat models. The left shows a control (wild-type) rat nucleus accumbens, while the right shows an experimental (knockout) rat nucleus accumbens.

Furthermore, the data from this study suggests that caffeine induces arousal and wakefulness by activating pathways in the nucleus accumbens that have formerly been associated with locomotion and motivational behaviors. This is a novel finding because it implicates caffeine in more than just the blocking of adenosine, but also in the activation of further neuronal circuitry, promoting a sense of “energy”.

A figure from Lazarus et al. showing the effect of caffeine on wakefulness. There is no significant increase in wakefulness in the A2A receptor knockout mice as more caffeine is administered. However, there is a significant increase in the wakefulness of wild-type mice as more caffeine is administered.

What I find super interesting about this study is how the researchers localized the antagonist effects of caffeine to the nucleus accumbems. In previous neuroscience classes, I learned of the association between the nucleus accumbens and cognitive processes such as motivation, pleasure and reward, thus implicating this brain region in numerous forms of addiction. With this in mind, I wish the experimenters had monitored the changes in behavior between the experimental and control rats when receiving differing levels of caffeine. This could be accomplished by using an intravenous self-administration task (IVSA). IVSA entails using chambers with small levers that, when pushed, cause specific drugs to be administered into the tail of that rat that pushed the lever (Figure 1). The researchers could perform IVSA for both control and experimental rats, and use either a saline or a caffeine solution as the respective drug. If this was done properly, I predict the control rats to show increased pushing of the lever when receiving caffeine compared to saline, corresponding to an greater feeling of pleasure and reward associated with the caffeine. Alternatively, I predict the experimental rats to show no significant difference in pushing of the lever between administrations of caffeine and saline because the caffeine does not affect their nucleus accumbens in the same way that it does for the control rats.

A very simplified version of the IVSA task in rat models.


Regardless, I find the study by Lazarus et al. to be extremely fascinating because, as a regular coffee drinker, it gives me insight to what is occurring in my brain!

Anyway, I’m about to go grab a coffee and walk around the city. Until next time!

~ Ethan Siegel



Huang ZL, Urade Y, Hayaishi O (2011) The role of adenosine in the regulation of sleep. Curr Top Med Chem 11:1047–1057.

Lazarus M, Shen H-Y, Cherasse Y, Qu W-M, Huang Z-L, Bass C, Winsky-Sommerer R, Semba K, Fredholm B, Boison D, Hayaishi O, Urade Y, Chen J-F (2011) Arousal effect of caffeine depends on adenosine A2A receptors in the shell of the nucleus accumbens. The Journal of Neuroscience 31(27): 10067-10075

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


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.

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