The Benefits of Sleep

           “If you die in your dream then you’ll die in real life too!” This was a belief I often heard whispered with reverence on the playground in my younger years. Older kids would nod sagely, as if they had a friend who had died in such a manner. For as kids, sleep was special and mysterious- and we all wanted more of it. But as we grow older, the specialness of sleep seems to fade as we focus more on getting at least the minimal amount of sleep needed for functioning. According to the Center for Disease Control, one in three Americans is sleep deprived, usually chronically. And this lack of sleep, however, impacts the important role sleep has in maintaining our mental health. Without adequate rest, we are prone to act in irrational and non-adaptive ways (such as binging on sweets or becoming easily upset).

        Although much research has focused on the detrimental effects of sleep deprivation, further research is need to understand what happens during this portion of non-consciousness. As far as we can tell, every living thing from trees to flies has some form of sleep or quiescence (quiet resting) during which it recovers from previous activity. In smaller, simpler organisms, this quiescence might only include clearing cellular debris but in more complicated organisms this sleep period is also important for changes in the brain. In humans, sleep is a privileged period of time when the brain doesn’t have to take in external information. Instead the mind prioritizes shuffling and re-organizing information learned during the day. We call this process of organizing and solidifying information memory consolidation. Most scientists agree that this process is always going on, but is especially prevalent during sleep. Memory consolidation is one reason why consistent sleep is so important for our daily lives.

        When we are sleep deprived, we restrict our brain’s ability to organize and prepare for the next day. This means that we are more likely to be forgetful, impulsive, and moody. College students who assume that they will do better in the exam by pulling an all-nighter are actually making it more difficult for themselves to succeed. Sleep deprivation is especially damaging because the part of our brain necessary for forming memories, the hippocampus, is particularly sensitive to sleep deprivation. It’s almost like a switch where at a certain point you are unable to learn and retain almost any information you are studying late into the night.

In addition to impairing memory, not getting enough sleep can also lead to motor control problems. If you’ve ever noticed that you seem to be less coordinated after staying up all night (or not getting enough sleep for a prolonged period of time), the loss of sleep is probably to blame. Coordinated motor control, especially for fine motor control is actually a complicated mental ability. So when you are sleep deprived, you aren’t able to respond as quickly or accurately to your surroundings. This problem has serious implications for professional truckers or others who drive long distances. In America, more than 1550 people are now killed by sleep-deprived automotive drivers.

The above mentioned problems are only a few of the consequences of sleep deprivation on the brain. In recent years there has been an escalating interest in the cognitive effects of sleep and why sleep is so important for a huge variety of mental abilities. But despite the accumulating evidence of sleep’s importance, Americans still tend to habitually stay up late and rise too early- putting us at a constant disadvantage. Thankfully, there are a few simple tricks that have been shown to help the chronically sleep deprived get some rest. First, going to sleep and waking at a consistent time each day helps us set our internal clock so it’s easier to fall asleep and we get quality rest. Another simple trick is treating your bedroom as a place reserved for sleep. Avoid watching TV or playing video games in bed as this creates a mental association between your bed and these activities instead of sleep. These tricks, along with avoiding caffeine in the evening, can greatly improve your ability to get restful sleep.

So maybe the schoolyard wisdom about dying in your dreams doesn’t hold up to modern science. In fact, the relationship seems to go the other way: a prolonged lack of sleep can actually cause death. But schoolyard children are right to think of sleep with awe and wonder.

There is some truth in the thought that sleep is a special period of time important to our health and well-being. We should retain some of that awe and wonder from our childhood years and realize how special sleep is.


Footnotes:
I would like to say a special word of thanks to ComSciCon16 for helping me craft this piece. It's a wonderful convention/program that has provided me with lots of feedback, as well as helping me make connections with other interested science communicators.  

Quick Update: Conclusion of my Research Abroad

Iliana's first night here and we stumbled onto a wine festival!

So I blinked, and now all of the sudden I'm on my last week in Lübeck... Where did the time go? Well, most of it has been spent double- and triple-checking all the equipment is working for our study. Because we are doing simultaneous EEG and fMRI, there are a lot of moving parts that could derail the study. Thankfully, I think we're finally worked out the last of the issues! This week, my last week in Germany, marks the beginning of data collection. Our first participant is this Wednesday, with hopefully more to be scheduled soon after. And although I'm leaving, my lab mate Iliana is taking over for the next 3 weeks.

So while I won't be here for the majority of the data collection, I'll still be helping from afar to make sure this project continues smoothly. Anyways, for family & friends who want to know what my last few weeks have been like, I've added some pictures below of my recent adventures!

While Daniel, my boyfriend, visited we put him to work as a pilot subject!

A visit to the CHOCOLATE MUSEUM in Hamburg = heaven

Urban beehives at the world-famous restaurant "Noma" in Copenhagen

Meals are reservation only and run about $400... Obviously we didn't go

Photo courtesy of Daniel- Copenhagen wanderings

Being ridiculous at Tivoli (amusement park in Copenhagen)

Copenhagen's iconic Little Mermaid statue in honor of Hans Christian Anderson

Daniel and Ariel ;)

A bamboo bicycle at the Danish Museum of Design

I would have had more pictures from recent adventures in Copenhagen and Hamburg (where I got to give a small guest lecture!), but my phone's camera has been non-operational for the last few weeks. So I'm looking forward to returning home not only to resume data collection for my master's project, but also so I can get this phone problem resolved! Chicago, Il- Here I come!

Pesky Programming, Massive Magnets, & Exciting Exploration

It's my second week in Lübeck, and I feel like I'm finally starting to settle in properly. Although moving slow, the project I'm working on is really progressing. My first week was almost all about making experiment design decisions while this past week has been all about implementing them. Well, that and testing out the equipment. It took me longer to figure out some programming quirks for an aspect of our task to run properly on the scanner computer.

The entrance to the MRI control room

Also, I'm sad to report that it seems I won't get to see what my brain looks like after all. My copper IUD is only rated as "MR safe" for up to 1.5 Tesla magnets (that's a measure of strength of the magnetic field) and we use a 3 Tesla magnet here. So although there's basically no evidence that I could be harmed by the electromagnetic field, once again I'm stuck in the control room and not able to get pretty images of my brain.

Anyways, beyond my personal disappointment, everything has been going really well.  I think with our current time line we shouldn't have too much trouble collecting enough participants in the time allotted. It helps that within the next week, Iliana (a fellow NU grad student) will arrive in Hamburg so we can really get running. In the mean time, it's pre-piloting, correcting, and more piloting for me! Oh! And I'm giving a short talk/presentation at an MRI colloquia as the official proposal to start running subjects. I'm more than a little anxious, but I think that it should go fine.

While my weekdays have been completely consumed with research, my weekends are reserved for exploration and fun! Last weekend, I spent Saturday exploring the city of Lübeck and getting my bearings. I also went to a fascinating museum about the Hanseatic League.

The famous Holstentor- or Holsten Gate- of Lübeck

Downtown Lübeck

On Sunday, I took a 30km (10 mile) ride on my trusty bicycle to the beach town of Travemünde. The ride itself was mostly through woods or around farms so it was a beautiful way to see the countryside. It was misty when I got to the beach, but I enjoyed wandering around and having lunch before cycling back home.

Travemunde

Travemunde

Sign reads "We live here"

This past weekend, I went a bit further afield. On Saturday, I journeyed into Hamburg- Germany's second largest city after Berlin. I can't say I got to see all of it, or even a good portion. I mainly spent time in the Planten un Blomen and Miniatur Wunderland.  The first is a huge park in the city that is absolutely lovely and peaceful, the second is my dream come true. A museum totally composed of miniature worlds and running trains. I can't even begin to describe how delightful it was! There were models of Switzerland, Hamburg, and the US, plus all kinds of fictional places.  I spent hours there and didn't even see all of the details. Did I mention the model builders also clearly have a sense of humor?

The creators have weird senses of humor- peeping monks watching a scantily clad woman try to fix her car 

I love the cyclist race with the kids trailing behind 

Just to give you an idea of the size of the displays- Swiss mountains

Anyways, yesterday I went to Schwerin for a quieter adventure than the big city. It's a town south east of Lübeck and famous for it's castle surrounded by lakes. It honestly looks like something out of a fairytale. Once again, I was drawn to some quiet park space to relax after seeing the castle. So overall, I must say my weekend adventures have been really lovely!

Schwerin, Germany

The fairytale castle- Schwerin

My best childhood friend, Courtney

And as a last note, last week I had the pleasure of my childhood best friend once again meeting me in Europe! Courtney stopped by for a few days in Lübeck before continuing her travels before her big graduation ceremony at Cambridge. So congrats to Courtney for finishing her post-bacc degree! I'm so happy for you!

Cheers to you Courtney!

Cross Country Collaboration

Yes, those wires are electrified...

This past Saturday, I completed the 11 mile/22 obstacle course of the Chicago Tough Mudder.

We  survived!

The very next day, I left the country for Lübeck, Germany.

Situated along the Baltic Sea, Lübeck was once a powerhouse of the Hanseatic League. 

My head is still spinning from the quick turn around! It's surreal to be sitting at a new desk at the Universität zu Lübeck, and yet be working on a project that I've had on my to-do list for months. Sometime earlier this year, my advisor broached the topic of collaborating with Dr. Heldmann & Dr. Münte on a sleep fMRI project. Of course, I immediately volunteered myself and started working on the study design, along with another graduate student from my lab. However, I'm the first of the two of us to make it to Lübeck. My lab mate wont join me in Germany for another 2 weeks, by which time I hope to have finished piloting and be ready to move into data collection.

Most of my time so far has been dedicated to finding the appropriate stimuli for German participants. We piloted the behavioral aspects of the study in Chicago but it seems famous locations to us aren't nearly as well known here. That being said, most of the preparation I did at Northwestern has ended up being very helpful.

My new ride for the next month, she's old but strong!

Our next step will be to set up everything in the fMRI scanner and make sure we have our timing down. While piloting a few different sequences, I'll finally get to be the participant in the scanner! After all these years (5 years!) of being involved with imaging research, I'll finally get to take a peek at my brain! I can't tell you how exciting that is to me! And after we sort out how we will be collecting the brain images, we'll get right to the piloting phase!

But that's looking pretty far ahead. I haven't even been in Lübeck for a full week yet. So far, I've managed to figure out the grocery store and purchased an old bicycle so I can bike to work rather than taking the bus. So for my immediate future, my current plan is to finally explore the city this weekend and enjoy the fact that I'm living abroad!

What should happen to memory for events that occur within an emotional context?

Before addressing what happens to memories within an emotional context, I would first like to argue that there is no such thing as not having an emotional context during encoding or retrieval of memories. We may not always have a strong valence for everything that happens in our lives, but we are constantly experiencing emotion of some sort. Whether that experience is low-level like boredom or fatigue, or high level such as in deep sorrow or great joy, I cannot imagine a time where I have not experienced some mood. But for the sake of argument, I will focus on memories that occur during a strong emotional context.

            According to current memory literature, both positive and negative memories are better encoded than less emotionally salient experiences. Based on fMRI studies, (among other mechanisms) this deeper encoding is most likely due to amygdala activation- both for positive and negative memories. In a 2006 study by Kensinger and Schacter, they found activation of the amygdala during encoding for positive and negative items. This activity later predicted recall for these emotionally salient items. However, this effect did not extend beyond highly emotional items. In keeping with my earlier statement, I would argue that the amygdala actually was engaged even during the more neutral items, but that the activation was so weak that it could not be picked up in the fMRI BOLD signal. In any case, this research demonstrates that the limbic system, and the amygdala in particular, are more active during emotionally charged situations and allow for deeper encoding.

It makes evolutionary sense that emotionally engaging experiences (especially negative ones) should be better encoded. It’s beneficial for an organism to remember to avoid negative experiences that hurt its chance of survival, and positive experiences should be better remembered in order to seek out similar beneficial situations. Thus, it is unsurprising that highly emotional memories engage neural systems beyond the medial temporal lobe.

However, extreme mood at memory retrieval can occasionally be detrimental. In a 2005 research study, researchers found that inducing a positive mood during recall led to more false memories in the Deese-Roediger-McDermott paradigm. However, inducing negative mood during recall did not show this effect. This research demonstrates that while heightened emotion during encoding can be overall beneficial, that same state during retrieval ends up causing people to falsely identify lure items as old. Thus, extreme emotion can be a double-edged sword when it comes to memory.

Works Cited:

Guastella, A. J., Mitchell, P. B., & Mathews, F. (2008). Oxytocin enhances the encoding of positive social memories in humans. Biological psychiatry, 64(3), 256-258.

Kensinger, E. A., & Schacter, D. L. (2006). Amygdala activity is associated with the successful encoding of item, but not source, information for positive and negative stimuli. The Journal of Neuroscience, 26(9), 2564-2570.

Storbeck, J., & Clore, G. L. (2005). With sadness comes accuracy; with happiness, false memory mood and the false memory effect. Psychological Science, 16(10), 785-791.

Why does memory change as we age? What changes?

As the baby boomer generation begins to enter seniority, concerns over mental performance for that age group are drastically increasing. Supposed brain training games like luminosity are attempting to cash in on this generational concern, but how is memory actually changing as the brain ages? Research seems to indicate that while episodic and source memories are affected by normal aging, semantic and procedural memory stay rather intact. Scientists believe this is due to how different regions of the brain atrophy during aging.

For example, Nyberg and colleagues found that episodic recall varied according to age but that semantic memory did not show this negative relationship. Thus older adults might struggle with remembering if they took their vitamin supplements that morning, but seemed to have no problem identifying the current president. In addition, memories for how to carry out actions seem completely spared. In studies using animal models, researchers found that aged animals performed equally well on an obstacle course compared to the younger animals (as long as gross motor control was normalized across groups). This explains why my 62-year-old mother is one of the best nurse anesthetists at her workplace, even when she might feel that some of her memory is eroding.

So why aren’t all memories made equal with respect to aging? Shouldn’t all types of memory decline equally as we age? Region-specific atrophy seems to be one of the key components in this dissociation longevity between the types of memories. In an imaging study conducted by Yonelinas and colleagues, healthy older adults showed reductions in hippocampal volume when recollection was diminished. Meanwhile recognition performance was dependent on entorhinal volume. These regions of the brain, found in the medial temporal lobe, tend to decrease in volume to a greater extent during aging than other regions. Whether these volume changes are due to the dying-off of neurons or reduction in synaptic connections, this seems to be a major cause of memory complaints in older adults.

So it is rather unfair to say that memory declines as we age, when not all memory is created equal. It is noticeable in daily life to recognize that you can’t call to mind where you met someone or how to use a computer function that your children just taught you. It is not immediately obvious that your memory of how to drive a car or ride a bike is still almost completely intact. I believe this is due to our limited connotation of the word ‘memory.’ When taking all forms of memory into account, healthy aging does not cause nearly the impairment that might be felt by an older adult. Because we rely so heavily on episodic and source memory in our social lives, we might not realize the multitudes of semantic and procedural memories that have been spared. Maybe brain-training games are effective, but it is important to also remember that an aging mind isn’t deficient in all memory types and that much expertise is actually spared.

Churchill, J. D., Stanis, J. J., Press, C., Kushelev, M., & Greenough, W. T. (2003). Is procedural memory relatively spared from age effects?.Neurobiology of Aging, 24(6), 883-892.

Nyberg, L., Bäckman, L., Erngrund, K., Olofsson, U., & Nilsson, L. G. (1996). Age differences in episodic memory, semantic memory, and priming: Relationships to demographic, intellectual, and biological factors. The Journals of Gerontology Series B: Psychological Sciences and Social Sciences, 51(4), P234-P240.

Yonelinas, A. P., Widaman, K., Mungas, D., Reed, B., Weiner, M. W., & Chui, H. C. (2007). Hippocampus, 17(11), 1134-1140.

Memory in the aging brain: doubly dissociating the contribution of the hippocampus and entorhinal cortex.

How should you study for an exam? Does it matter if the test is essay or multiple choice?

As the academic trend of more and more standardized testing continues, many students have started to look for study tips to make the process less painful. And while there may be some unique tricks, the perhaps best-known ones are also the ones usually under-utilized. The two simple habits of getting a good night’s rest before an exam and quizzing yourself over the material are the most reliable ways to ensure better test performance.

To begin, good test performance isn’t just about what your brain is doing during wake, but also the consolidation and reorganization of memories that happens during sleep. In 2006, Walker and Stickgold published a review of the evidence demonstrating that during sleep, memories are more deeply encoded such that they can be retrieved at a later time. Research supports the hypothesis that during sleep, memories of the day are transformed into a deeper encoded form, which can be more easily accessed and integrated into other previous knowledge. This ability to contextualize new information within previous experiences or knowledge allows for incorporated networks that can help us address multi-faceted problems, such as when taking an essay exam. Additionally, a lack of sleep can actually be detrimental not only because studied material isn’t assimilated as well, but also because sleep deprivation leads to difficulties with attention. Both total sleep deprivation and sleep restriction affect the ability to maintain vigilant attention, a skill absolutely necessary for any sort of exam (Lim & Dinges, 2008). Thus adequate sleep before an exam prevents disrupting mind wandering and has the added benefit of helping consolidate previously studied information.

 

Me in philosophy class freshman year- thank god it wasn't during an exam...

Another strategy for preparing for exams is to use the practice effect. Psychologists have recognized the practice effect for decades now, demonstrating that practicing testing or quizzing yourself improves your ability to call that information to mind later (Sutterer & Awh, 2015). Essentially, when studying it is in best practice to constantly test yourself, or have others make up test questions for you. Beyond the obvious benefit of realizing which subjects aren’t as well engrained, research has shown that testing helps make memories more accessible to be called upon later. This technique can be used both for essay tests (by outlining responses to potential prompts) and for multiple-choice exams. Although the practice effect might require taking some time to meet with a study partner or group and quiz each other, the benefit of such a habit will certainly lead to improved testing scores.

By combining the practice effect with a sufficient night’s sleep, students can better prepare for all sorts of exams they may experience in their academic careers. In the case of these techniques, it doesn’t matter what kind of exam is given, or what material is covered. Although study habit can be difficult to form, sleep and self-testing will lead to a better performance than could be achieved by staying up all night to cram by re-reading notes.

Works Cited

Lim, J., & Dinges, D. F. (2008). Sleep deprivation and vigilant attention. Annals of the New York Academy of Sciences, 1129(1), 305-322.

Sutterer, D. W., & Awh, E. (2015). Retrieval practice enhances the accessibility but not the quality of memory. Psychonomic Bulletin & Review, 1-11.

Walker, M. P., & Stickgold, R. (2006). Sleep, memory, and plasticity. Annu. Rev. Psychol., 57, 139-166.