Author Archives: Alexandru Lenut Rus

Chill, it’s just coffee!

Dear friend,

As I wrap up my last week in Paris, I’ve started noticing a peculiar number of coffee shops at just about every corner. Usually filled with people enjoying pastries accompanied with a small coffee, these cafés represent a snapshot of Parisian life. Outside of the café’s, people typically sit at the small but cleverly ornamented tables calmly and almost elegantly sipping on their simple beverage while reading the newspaper or chatting with a friend.

Cafes paris

Its so easy to find a café in Paris! (photo courtesy of google maps)

This isn’t anything like back at Emory, though! Unlike the sleep deprived college students at Emory who drink coffee as on-the-go rocket fuel, Parisians especially savor their brewed drinks as a vital part of their day. Nobody’s running around, on the go, fumbling with their food and coffee on the train, or spilling their drinks as they rush among pedestrians. This honor rests almost exclusively with American tourists, and in fact, remains as one of my surefire methods to find and befriend Americans in Paris!


Coffee in Paris

I should mention that I personally don’t enjoy drinking coffee this way, or in any way for that matter. I find it far too bitter and it seems that even if I can gulp it down with heaps of added sugar, caffeine and I don’t get along very well. It all started back in middle school when I drank a giant bottle of Pepsi during a back-yard soccer game (This would be forbidden at Emory, a school renowned for only selling Coke products on campus!). After about 20 minutes I felt a burst of energy as I sprinted down the field, but my heart raced, and my face got incredibly warm. Panicking about my racing heart, I ended up going to the hospital after the game, only to have the doctors tell me I was fine. Of course, by the time I got there, the effects of the caffeine faded. Since that experience though, I try to stray away from caffeinated drinks because of the side effects that come with it.

Tired and hot after soccer

Tired and hot after caffeine and soccer (


However, I recently participated in a small group-experiment as part of a project for our class that involved drinking coffee. As a willing participant, I bought coffee from the local café at Cité Internationale, and quickly drank one cup before completing a series of reaction time tests to examine the effects of caffeine on reaction time.

The coffees we drank for our experiment!

The coffee we drank for our experiments!


My reaction time increased, but interestingly so did my perceived body temperature and alertness. This got me thinking about the effects of caffeine on the body. How does this drug, available so readily throughout most of the world, affect the brain and body? Once again, equipped with Neuroscience, I turned to the Internet in my search for answers.

It turns out that caffeine works by blocking the activation of brain processes responsible for regulating sleepiness and fatigue. These processes normally activate when a certain neurotransmitter, adenosine, binds to a certain receptor, the adenosine receptor. When awake, adenosine builds up in the body and eventually binds to its receptor, signaling the body to sleep. Caffeine also binds at this site, but it binds without activating fatiguing processes, and just gets in the way of adenosine binding. By doing so, caffeine keeps its users energized (Fredholm et al., 1999). Previous research also indicates that caffeine increases dopamine release in the striatum, and nucleus accumbens, areas of the brain responsible for motivation, reward, and sympathetic nervous system activities typically known as fight or flight systems (Balthazar et al., 2009).

In a recent study, Zheng et al. (2014) tested the effects of caffeine on temperature regulation and neurotransmitter release in the preoptic area and anterior hypothalamus (PO/AH) of the brain, areas responsible for regulating body temperature. According to their study, researchers chose to study these areas because increased dopamine activity here leads to a better tolerance for heat storage in the brain and facilitates an increased metabolic rate (Balthazar et al., 2009). To investigate whether caffeine helps produce these enhancing effects, researchers measured temperature, oxygen consumption, and neurotransmitter presence in rats during rest and exercise states. In a total of 10 male winstar rats, Zheng et al. (2014) measured baseline serotonin (5-HT), dopamine (DA), and noradrenaline (NA) release in PO/AH using a microdyalisis probe or cannula for control. This tiny filter collected neurotransmitters and allowed experimenters to analyze measurements. To further test for temperature and oxygen consumption, researchers measured core and tail skin temperature in the same spot for all rats, and oxygen with an oxygen/carbon dioxide measuring box. One hour before rats were placed in the box to run on a treadmill until fatigue at an 18m/min pace, investigators intraperitoneally injected (injected into the abdomen) rats with saline, 3mg/kg caffeine, or 10mg/kg caffeine. (See Link1 at the bottom for a video of rats running on a treadmill!)

Oxygen/Carbon Dioxide measuring mechanism (

From their data, Zhang et al. (2014) found that at rest, 3mg/kg caffeine levels did not result in any significant changes. However, at 10mg/kg, caffeine caused significantly higher core and tail temperatures, higher oxygen consumption, and extracellular DA and NA in the PO/AH. Data also showed that caffeinated rats showed increased endurance, and could run longer before fatigue set in. The researchers interpreted this to mean that caffeine facilitates dopamine pathways in the brain that lead to physical enhancements, specifically by modulating the PO/AH in a way that allows the brain to work under higher energy levels. I personally think of this as caffeine rearranging the brain’s thresholds for what we consider a state of exhaustion, and increasing energy consumptions by resetting the thermostat so we can function at a higher level. I  particularly chose this study  because the comprehensive testing used in the methods mimics these same high stress functioning levels I experienced while playing soccer.

I think as a whole the findings are incredibly interesting, and in my opinion, make perfect sense when interpreted this way. However I think that the researchers should definitely have included more details on the effect of caffeine on heart rate, as well as more incremental investigation on the effects of caffeine doses between 3 and 10 mg/kg. I would also like to see a larger sample size, or at least more than one trial per rat, as a sample size of 10 makes it difficult to collect meaningful data. I also wonder though, how long can this high energy state last before burning the body’s metaphorical engines? Perhaps future studies could test the effects of chronic caffeine use on prolonged energy levels.

As I continue my time in Paris, it feels great to see scientific explanations for everyday events. This past spring, I remember seeing a “contains caffeine” label on one of my running snacks when I ran a marathon. At the time, I thought that caffeine simply keeps you more awake, but little did I know that it facilitates increased endurance levels!

coffee chews
Caffeine chews

I’m glad neuroscience keeps sneaking up on me, pleasantly surprising me with answers. Who would have known that it would answer my childhood questions and help me chill out about coffee’s side effects.

For now, maybe coffee is not all that bad.

Here’s to new experiences and breaking out of my comfort zone!

Until next time,




Balthazar CH, Leite LHR, Rodrigues AG, Coimbra CC (2009) Performance-enhancing and thermoregulatory effects of intracerebroventricular dopamine in running rats. Pharmacol Biochem Behav 93:465–469

Fredholm BB, Bättig K, Holmén J, Nehlig A, Zvartau EE (1999) Actions of Caffeine in the Brain with Special Reference to Factors That Contribute to Its Widespread Use. 51.

Zheng X, Takatsu S, Wang H, Hasegawa H (2014) Pharmacology , Biochemistry and Behavior Acute intraperitoneal injection of caffeine improves endurance exercise performance in association with increasing brain dopamine release during exercise. 122:136–143.


Watch your step!

Dear Friend,

The phrase “Attention à la marche en descendant du train” echoed through the platform as I grabbed my bag and stepped from the train. Ready to explore the beautiful, world-renowned city of Paris, I proudly raised my head and firmly stepped forward with intent. However, I couldn’t help but ask two very important questions. Where am I, and where can I find the delicious food?

Thoughts of savory crepes, warm baguettes, and chocolate-filled croissants distracted me during my voyage, somehow causing me to step off at the wrong station. I stopped and unfolded my pocket metro map, promptly realizing my disorientation landed me somewhere in the center of the complex Parisian underground maze. I wondered how I lost track of time so fast by simply staring through the window of the train. I was practically blinded by my quest for French desserts, but just about ready to go back home to Cité Universitaire.


In the two subsequent weeks that zoomed by, I paid much closer attention to my surroundings. Though I indulged in wonderful Parisian delicacies, and adapted to the city life, I also started perceiving my environment with more respect for sensory information. Doing so kept me from getting lost and allowed me to focus more. This habit greatly coincided with our neurosciences classes that started focusing on the brains interaction with bodily functions like motion, vision, and hearing.

With my senses primed, I took note of Paris’ every little detail, and learned how to travel as an expert tourist and passenger, exploring what Paris has to offer both above and below ground.

Above ground, I saw beautiful gardens and remarkable architecture. I experienced the jostling waves of the Seine while on a boat tour, and got dizzy staring up at the Eifel tower. I also heard countless sirens, and noticed pedestrians don’t care about traffic lights.

Below ground, I listed to musicians perform inside metro hallways and I watched entertainers dance in moving trains, all accompanied by the hum of bustling crowds and the sound of screeching metal pressing together to slow down trains. In this wild sub-terrain, I also noticed that closing automatic doors don’t care about rushing passengers, and warnings of “attention à la marche” exist for a reason.

train1Some things however literally caught my eye. As I stared outside of a train window one day, I caught a short glimpse of a nearby pole while we zoomed by. This was strange considering how slow and peaceful the buildings and scenery in the background passed by. I looked more closely, noticing the tracks below the train and the platform steps to the side of the train, moved incredibly fast while the landscape a few hundred meters out barely seemed to move at all. At this speed, the steps were actually dangerous!


I realized my mind must be playing tricks on me since the train was moving at the same speed compared to the ground, shared by both the tracks and the landscape. A few days later, I noticed this effect again at the roundabout circling the Colonne de Juillet at the Place de la Bastille (a great monument, see link 1)where cars near me seemed to move faster than those furthest away. I wanted to know more so, like any student investigator, I decided to search and see if neuroscience could provide and answer to this puzzling question.


Screenshot at Bastille from GoogleMaps

The above process, called motion parallax. is a visual cue that signals depth where objects that are closer appear as if they move further across the visual field, while those that are farther away move less (Kim et al., 2015)


A recent study by Kim et al. (2015) looks at the neuroscience behind this cue and explores a specific area of the brain called the middle temporal (MT) area that could be responsible for the perception of depth from motion parallax. Although another study by Nadler et al. (2008) found that this part of the brain carries information about depth, it was not necessarily clear what kind of information was transmitted. The data from Kim et al. (2015) fill this gap by hypothesizing that the MT specifically carries information about the perception of depth.

The experimenters take two male monkeys, trained to respond to dots they see on a screen, and set them up with recording devices for their eyes. Researchers then fix the monkeys with electrodes in their MT areas, located by the use of MRI imaging. Finally, testing involves placing monkeys on a motion platform where the monkeys’ eye movements and brain signals provide computer-collected data.

The results from Kim et al. (2015) show that the MT will actually predict a monkey’s decision regarding its perception about depth. This paper gives a lot of support to the field of neuroscience because it reveals more information about the MT with sound methods.

The study finds that the MT further contributes to the perception of depth but it does not show that the area is entirely responsible perception. Although very recent, this article comprises one train-cart in a long train of studies on the MT. It lacks particular novelty and demonstrates that there is still much to learn about vision and the brain. Research in animals should definitely continue, but it would find it very interesting blend more than one study to find bigger applications. For example, Nawrot and Stroyan (2012) show that humans require about 30ms to detect depth from motion parallax. What if scientists could use deep brain stimulation (DBS) in the MT to provide brain enhancement for car accident prevention? I am incredibly excited for this research to continue.

Through my city travels, I hope to walk down the beautiful streets of Paris and remember that neuroscience allows me to navigate safely and effectively. My time in Paris is showing me that even though life has twists and turns, senses are needed to make “sense” of them (pun intended). I hope one day, a breakthrough in research and technology will allow us to better watch our steps!


Kim HR, Angelaki DE, DeAngelis GC (2015) A functional link between MT neurons and depth perception based on motion parallax. J Neurosci 35:2766–2777 Available at: [Accessed June 8, 2015].

Nadler JW, Angelaki DE, DeAngelis GC (2008) A neural representation of depth from motion parallax in macaque visual cortex. Nature 452:642–645 Available at: [Accessed June 8, 2015].

Nawrot M, Stroyan K (2012) Integration time for the perception of depth from motion parallax. Vision Res 59:64–71 Available at: [Accessed June 8, 2015].


link 1