Tag Archives: working memory

bottoms up! cognition down?

drinking but make it ~~patriotic~~

Walking around the city of Paris, it is hard to miss the fact that we are in a country submerged in a long, liquid history with wine and a current population dedicated to upholding this wine drinking culture.  “For many individuals, drinking wine has become an identity-building process by which they become part of a new form of civil community constructed around a nostalgic view of a rural and authentic France” (Demossier, 2010, p. 13). Apparently, the French are quite a nostalgic bunch then, and at all times of the day. Whether it’s with a well-plated charcuterie board, a medium rare steak, or sans any food in front of them, I cannot recall a time when I did not walk through a Paris street without seeing anyone sitting outside at a café terrace without a glass of wine accompanying them.

a typical scene of Parisian merriment

As a nation with casual drinking during meals ingrained into the collective psyche, I was interested in seeing whether this difference in mentality would manifest in a difference in drinking habits – binge drinking in particular – among the young people of France and America. Binge drinking (BD) is typically defined as heavy alcohol use of four or five drinks over a short period of time. From 2009 to 2013, the prevalence of those partaking in BD among university students in France was about 30% in the period of a month (Tavolacci et al., 2016). During this same period of time, the percent of 18-22-year-olds in America binge drinking within a month wavered around 40% (White and Hingson, 2014). The underlying factors leading to the prominence of binge drinking is a bottle to be uncorked another time, but today I will be looking into the effects of binge drinking on cognitive function in young people.

We’ve all seen the short-term side effects of binge drinking – in fact I think I saw some of it walking around the Bastille area of Paris one day after dinner – but what about the unseen and long-term effects in the brain? As binge drinking is usually associated with those of college age whose primary occupation is often school, I wanted to see how much researchers know about what is happening to a brain and its function with frequent alcohol use.

In a 2009 study, 42 binge drinkers and 53 controls from between age 18-20 were tested. Scalp electrodes were used to measure event-related potentials (ERPs), which are measured brain responses that are a result of a specific sensory, cognitive, or motor event and a way to evaluate brain function. Subjects were asked to perform a visual working memory task, a task where visual information must be remembered and manipulated quickly when prompted, and then the components of their ERPs were compared. The results indicated that there was the presence of an electrophysiological difference between the binge drinker and the control group, and that higher levels of attentional efforts were required from the binge drinking group to differentiate between relevant and irrelevant information to effectively process working memory (Crego et al., 2009).

 

an example of the components of what an ERP may look like based on electrode measurements

 

Another study in 2011 tested 40 binge drinkers (13 females, 27 males) and 55 controls (24 females, 31 males) between the ages of 16 to 19. Researchers conducted neuropsychological testing, substance use interviews, and a spatial working memory (SWM) task, which requires retention and manipulation of visuospatial information, during functional magnetic resonance imaging (fMRI). Links between BD status and gender were found in brain regions spanning the bilateral frontal, anterior cingulate, temporal, and cerebellar cortices. In all regions, female binge drinkers showed less SWM activation than female controls; however, male binge drinkers actually showed greater activation of SWM which linked to better spatial performance (Squeglia et al., 2011). The results of this study seemed to indicate that females may be more vulnerable to the neurotoxic effects of binge drinking during adolescence, while male brains may be more resilient to the harmful effects of binge drinking (where does the male privilege end??).

an example of a simple spatial working memory task

While ERPs and SWM are ways to assess brain function, I believe they can’t fully encompass cognitive performance, which synthesizes aspects of memory, attention, and reasoning. Overall, I believe the exact effects of binge drinking on the human adolescent brain will always be difficult to elucidate because of the many confounding factors that cannot be controlled for in correlational studies. However, this does not mean that this topic should be any less deserving of research because of the important implications the results can have for adolescents around the world and their brain health. For now, perhaps we should all follow the example of the Parisians and enjoy in moderation. Cheers for now!

 

Bibliography

Crego A, Rodriguez-HolguõÂn S, Parada M, Mota N, Corral M, Cadaveira F.(2009). Binge drinking affects attentional and visual working memory processing in young university students. Alcohol Clin Exp Res. 33(11):1870–9. 10.1111

Demossier, M. (2010). Wine Drinking Culture in France: A National Myth or a Modern Passion? (French and francophone studies) (p. 13). Retrieved from https://books.google.com.

Marie-Pierre Tavolacci, Eloïse Boerg, Laure Richard, Gilles Meyrignac, Pierre

Dechelotte, et al., (2016) Prevalence of binge drinking and associated behaviours among 3286 college students in France. BMC Public Health, BioMed Central, 16, pp.178.

Squeglia, L.M., Schweinsburg, A.D., Pulido, C. & Tapert, S.F. (2011) Adolescent Binge

Drinking Linked to Abnormal Spatial Working Memory Brain Activation: Differential Gender Effects. Alcoholism: Clinical and Experimental Research, 35, 1831-1841.

White, A. & Hingson, R. (2014) The burden of alcohol use: excessive alcohol consumption and related consequences among college students. Alcohol Res, 35, 201-218.

Image 1: from Demossier (2010) p. 10

Image 2: http://www.wikileaks.info/lifestyle/nightlife-in-paris/

Image 3: http://faculty.washington.edu/losterho/erp_tutorial.htm

Image 4: https://www.researchgate.net/publication/263156210_Nicotine_Impairs_Spatial_Working_Memory_while_Leaving_Spatial_Attention_Intact__Time_course_and_disruption/figures?lo=1&utm_source=google&utm_medium=organic

 

Walking through Paris

Amongst the many changes I have experienced while in Paris, I noticed that I am walking considerably more than I usually do. While most people are aware of the positive impact walking and exercise can have on the body, I am dedicating this post to exploring the effects of exercise on the brain.

Thanks to my handy Fitbit (yes, I know I am a little obsessed), I am able to track my daily activity, so I have a very good idea about how much exercise I am getting. Between going to class, touring museums, and exploring getting lost in the streets of Paris, I am walking an average of over 8 miles every day. Paris is a very “walk-able” city, and my friends and I regularly opt to walk to our destinations instead of using the metro. I know that this must be affecting my cognitive ability, because even while operating on 4-6 hours of sleep every night, I am able to focus and work surprisingly well.

Fitbit evidence that 1) I am walking crazy amounts in Paris, and 2) I can justify eating multiple pastries a day*  *point 2 has not been scientifically proven

Fitbit evidence that 1) I am walking crazy amounts in Paris 2) I can justify eating multiple pastries a day*
*point 2 has not been scientifically proven

A recent study in college-aged females found that after only a single session of moderate exercise, participants showed increased brain activation during a working memory task (Li et al. 2014). Working memory is a limited brain resource that temporarily stores, processes and updates action-related thinking. It is utilized when you need to actively handle information, and your working memory capacity is an important measure of cognitive function. The researchers in this study used a modified N-back task to measure working memory. This task requires participants to attend to a sequence of stimuli, and determine if the current stimulus matches a stimulus that was “N” steps earlier in the sequence. The task gets more and more difficult as N increases, because it becomes harder to keep track of when a stimulus appeared.

A visual representation of the N-back task used in the study by Li et al. (2014)

A visual representation of the N-back task used in the study by Li et al. (2014)

To compare brain function, the subjects performed this task while in a functional magnetic resonance imaging (fMRI) machine, once following exercise, and once following a rest period. The fMRI measures blood oxygenation, which provides a visual image of brain activation. While there was no significant change in subject performance on the task, the data show more brain activation in the exercise condition, especially in the prefrontal cortex (PFC) and medial occipital cortex during the 2-back condition. The PFC is well recognized to be important for working memory, and the specific areas of the occipital lobe that changed are also involved in online processing. The lack of performance change limits the conclusions that can be drawn from this study, but it is reasonable for me to assume that my working memory capacity is positively influenced by the increased exercise I get in Paris. The researchers clearly showed that exercise influenced the brain areas important for working memory in subjects of my same age and sex, and this effect would likely be enhanced by an extended exercise routine like mine. A future study could explore the effect of chronic exercise, or use multiple behavioral measures to see if that leads to more pronounced changes in working memory performance.

Working memory is not the only brain function influenced by exercise. In fact, hundreds of studies explore how exercise can change the brain. One of the most common focus areas is how exercise increases brain-derived neurotropic factor (BDNF) in the hippocampus. BDNF is very important for brain plasticity, and the hippocampus is highly involved in learning and memory. One study found that exercise enhanced memory and cognition in rats, through the action of BDNF and the pathways it influences (Vaynman, et al. 2004). A different study focused on the non-neuronal cells in the brain, called glial cells (Brockett, et al. 2015). They found that running influenced synaptic plasticity in rats, producing widespread positive effects in both neurons and glial cells in areas associated with cognitive improvement. The last study looked at showed how exercise can help people’s mental health by reducing the stress hormone cortisol, through overall regulation of the hypothalamic-pituitary (HPA) axis (Zschucke et al. 2015).

I walked almost 10 miles before stumbling upon this set at Fete de la musique, and the journey was as fun as the event!

I walked almost 10 miles before stumbling upon this set at Fete de la musique, and the journey was as fun as the event!

It is so interesting to hypothesize about the different ways that my brain may be changing in response to something as simple as walking. Evidence suggests that my working memory capacity, brain plasticity, and mental health are all influenced by exercise. Now that I only have one week left to enjoy Paris, I will make sure to walk everywhere to experience, learn and improve my brain as much as possible. With all of the positive effects Paris seems to have, I know I will be planning a return trip the second I get home!

 

References 

Brockett AT, LaMarca EA, Gould E (2015). Physical Exercise Enhances Cognitive Flexibility as Well as Astrocytic and Synaptic Markers in the Medial Prefrontal Cortex. PLoS ONE. 10(5): e0124859.

Li L, Men W-W, Chang Y-K, Fan M-X, Ji L, & Wei GX, (2014). Acute Aerobic Exercise Increases Cortical Activity during Working Memory: A Functional MRI Study in Female College Students. PLoS ONE. 9(6): e99222.

Vaynman S, Ying Z, and Gomez-Pinilla F, (2004). Hippocampal BDNF mediates the efficacy of exercise on synaptic plasticity and cognition. European Journal of Neuroscience. 20: 2580–2590.

Zschyke E, Renneberg B, Dimeo F, Wüstenberg T, & Ströhle A (2015). The stress-buffering effect of acute exercise: Evidence for HPA axis negative feedback. Psychoneuroendocrinology. 51: 414-425.