Study of Human Mobility- An Invasion of Privacy or a Behavioral Goldmine?

    In the modern age, we often talk about the importance of protecting our privacy and data online. Our computers and smart devices have the capacity to collect immense amounts of data about us and our online habits, especially with tools such as auto-filling passwords and saving our credit card information. This data capture is extended even further with other smart devices being purchased and used (for example: refrigerators, smart speakers, security systems, vehicles). In our increasingly digital age, there is often much debate about how much of our data should be accessed by commercial organizations, and how it could be useful for science. Researchers are often provided access to large amounts of data and devices of data collection for studies involving large populations or naturalistic observations of the general public. Human mobility is one of those topics, in which social science researchers are trying to find information about human migration and movement in response to different factors over time. The question arises- to what extent can this research go for data use and is it justified? 

    Published in February of 2022, a paper entitled “Shifting Temporal Dynamics of Human Mobility in the United States” looked specifically at differences in human mobility according to peak times of day. For example, seeing the most movement (defined as “the use of public space”) during the hours of 7am and 5pm would indicate that people start and end their day at these times. The researchers used data from SafeGraph, an organization that collects data and sells it to researchers, businesses, and other consumers. Over the course of 2019 to 2020, they looked at differences in mobility during the day throughout the country. Once the pandemic struck at the beginning of 2020, they noticed major differences in some areas that they noted in their conclusion. They argued that following with the policies restricting human mobility in March 2020, there was a significant difference in temporal mobility compared to 2019; with daytime mobility starting later, evening mobility starting earlier, and differences in these trends across the country. 

    A team of researchers including a man named George Thiruvathukal wrote a paper (awaiting publication) entitled “Observing Human Mobility Internationally During Covid-19” that analyzed a large sum of human data during the Covid-19 pandemic. Their goal was to quantify human mobility during different stages of the pandemic in different regions of the world according to how strict the policies were surrounding isolation and restrictions. Using a network of public cameras (such as security cameras on buildings), they were able to develop a system of capturing movement data from April 2020 through March 2021 in three states of the US and five countries outside the US. They analyzed the data using a model capable of recognizing people and vehicles in the images and put together the results in graphical form. They found that the areas with stricter restriction policies and lockdowns had mobility that closely matched the leniency of the policy (when the policy changed, so did mobility). Areas with more relaxed policies had less direct correspondence between policy change and mobility change. The authors concluded that their method of computer analysis using data from cameras was an effective method of quantifying mobility, and one that future studies could also make use of with more cameras and areas being analyzed. 

    Both of these studies have interesting findings regarding how mobility changed during the pandemic. However, it is still difficult to conclude how human mobility is classified. From the research perspective, these two papers could point to how the collection of human data already produced these significant findings, proving that it is a goldmine that could inform many research discoveries and policies in the future. In the personal perspective, it could be considered an invasion of privacy if data is being collected and used without knowledge of it. I hope that researchers in the future will use the increasing available data about individuals responsibly and ethically or seek informed consent. Ideally, we can find a compromise where researchers can achieve their research goals as well as respect the privacy of personal data.

 

References:

Sparks, Kevin et al. “Shifting temporal dynamics of human mobility in the United States.” Journal of Transport Geography, vol. 99, 2022, https://doi.org/10.1016/j.jtrangeo.2022.103295.

Thiruvathukal, George et al. “Observing Human Mobility Internationally During Covid-19.” IEEE Computer Society, 2021. 

How Bilingualism Changes Our Brain

About half of the people in the world can speak at least two languages fluently. Evidence suggests that people who are bilingual tend to have a better attention span and memory. Previous studies have shown the bilingual children have a better working memory than monolingual children, as well as a possibly recovering better from a stroke and delaying the symptoms of dementia (“The Advantages of a Bilingual Brain,” 2018).


In a study titled, “Early bilingualism, language attainment, and brain development” by Jonathan Berken et al., discusses the brain plasticity, structurally and functionally, in children who are bilingual. It was concluded that adults who take on a second language later in life will not have the same brain as someone who learned when they were a child, due to the optimal periods for learning language that only occur in young children. They found that when at least two languages were taught to children from birth, the structure and function of their brains seemed to be more organized in comparison to a monolingual child. Neuroplasticity can still occur in adults acquiring a second language, but it is much more limited than a child's brain (Berken et al., 2017).


“The Advantages of a Bilingual Brain” (2018), focuses on the differences between people who are bilingual versus monolingual, structurally and functionally. Not only do bilingual individuals have a better memory and attention span, but new research also suggests that they recover better after suffering a stroke, and symptoms of dementia can be delayed up to four years in comparison to someone who is monolingual. Although being bilingual can delay dementia symptoms a few years, this is due to the strengthening of the cognitive reserve, which you can also accomplish by playing a musical instrument, exercising, or staying social. Studies have shown that there is more gray matter in the left inferior parietal region of the brain, as well as less white matter loss while aging.


Both pieces of literature agree that brain plasticity causes the structure and function of the brain to change when a young child develops more than one language, which can be beneficial in many aspects. It is widely agreed that learning multiple languages at a young age causes the brain to wire differently due to brain plasticity. Bilingualism can have many positive effects on our brain structure and function. The effects on the brain due to bilingualism are still being studied, and hopefully in the future we can gain a better understanding of it and all the benefits and effects on the brain in children and adults.

References

The advantages of a bilingual brain. OpenMind. (2019, March 4). Retrieved May 2, 2022, from              https://www.bbvaopenmind.com/en/science/research/the-advantages-of-a-bilingual-brain/


Berken, J. A., Gracco, V. L., & Klein, D. (2017). Early bilingualism, language attainment, and brain         development. Neuropsychologia, 98, 220–227. https://doi.org/10.1016/j.neuropsychologia.2016.08.031

The Future Seems Like Is Here

    Having brain-reading devices inside the brain to control machines sounds like a concept from a sci-fi book. An article from Nature by Liam Drew (Drew, 2022), discusses such scientific advantages, their evolution until now, as well as how they could change the life of someone who has been left paralyzed. The article talks about a few different research teams that work with brain-computer interface (BCI) technology with hopes of improving the lives of paralyzed people, by helping them move and/or communicate in one way or another. Caltech has one such group of researchers, led by Dr. Andersen, that are working with implanting electrodes into the cortex to record activity of neurons and translate those signals into thoughts/intentions through algorithms. For example, a person with such an implant can control a cursor on a computer screen or control a robotic arm by just using their brain. The technology and the research have evolved quickly and have led to major achievements for the scientific community; the technology has helped patients regain a form of sense of touch, produce speech, and communicate by just thinking of themselves handwriting (Drew, 2022). 

    The progress of BCIs over the years has been rapid, especially if we think about the fact that the first person to receive such an implant for the long-term did so only in 2004. Since then, the list of the things someone with a BCI can do has gotten longer and the control is more precise and efficient. Dr. Hochberg, from Brown University and the Massachusetts General Hospital, attributes that, not only to the fact that multiple BCIs are now getting implanted in several parts of the brain but also because of “machine learning, which has improved the ability to decode neural activity. Rather than trying to understand what activity patterns mean, machine learning simply identifies and links patterns to a user’s intention” (Drew, 2022). This makes sense if we think about how everything in the brain is connected, works together, and overlaps to result in specific activities. At the same time, it makes activities a lot more natural and the technology easier to use for the participants. 

    BCIs can greatly improve the quality of life of people with paralysis. The article says, “Asked what they want from assistive neurotechnology, people with paralysis most often answer “independence.” For people who are unable to move their limbs, this typically means restoring movement,” (Drew, 2022). The scientific community believes that BCIs can provide that. Dr. Ajiboye’s team from the Case Western Reserve University work on stimulating the muscles of the patient through electrodes and controlling them through BCIs. With this method, they achieved the movement of previously paralyzed limbs in patients. Dr. Gaunt, along with Dr. Collinger from the University of Pittsburg, accomplished the creation of a prosthetic robotic arm that gives the ability of a form of sense of touch. Dr. Andersen from Caltech is working on “trying to decode users’ more-abstract goals by tapping into the posterior parietal cortex (PPC), which forms the intention or plan to move” (Drew, 2022). As a result, the intended movement becomes much more natural for the person with the implant. 

    In addition, the technology of BCIs can be life-changing for people who have lost their ability to communicate due to brain injuries. Dr. Chaudhary from the University of Tübingen was able to help a participant who was unable to both speak and move, due to ALS, communicate. The researcher used sound, “that mimicked the man’s brain activity — a higher tone for more activity, lower for less — and taught him to modulate his neural activity to heighten the pitch of a tone to signal ‘yes’ and to lower it for ‘no’” (Drew, 2022). 

    The road to making such a technology public and commercially used is not short but it is attainable. According to the article, more testing needs to get done on a larger number of participants, research needs to make sure that implants can be used universally with the same benefits across the participants, and manufacturers should be able to make large amounts of reliable/long-lasting BCIs, all while keeping the prices in a range that the market can support. The company Blackrock Neuroteck is on the right track. It produces the implants that have mostly been used in clinical trials and, “wants to market a BCI system within a year…The company came a step closer last November, when the FDA, which regulates medical devices, put the company’s products onto a fast-track review process to review process to fascillitate developing them commercially” (Drew, 2022). The company is also working on wireless implants, as is the company Paradromics. The company Synchron’s wireless implants have also been put on a fast-track review by the FDA, after having achieved successful small-scale trials. Finally, Elon Musk’s Neuralink has also created implants that have only been tested on monkeys. These implants have advantages such that they, “bend with the brain and reduce immune reactions” (Drew, 2022), which could be revolutionary for the field.  

    The different companies also have different goals in mind. An article from the Insider by Grace Kay (Kay, 2022), gives a bit more insight in the Neuralink company and its goals. From the article, it seems like Elon Musk, the owner of the company, does not necessarily have in mind just people who need the technology because they are paralyzed, but broad use of such technology to connect humans with machines. This is clear by his statement that the Neuralink technology, apart from eventually being able to help people with diseases such as Parkinson's, will also help everyday communication and, “will be the future of phones and smartwatches” (Kay, 2022). This view seems to be quite different from other companies that strictly aim to use BCIs for people who actually need them. The author also brings attention to Elon Musk’s words on the difficulties the company is facing. One of the company’s engineers said, “that the electrodes in the chip were “too small for a human to handle”,” while the owner of the company compared the difficulty of the technology to that of smartwatches. Finally, the article points out that the company has not tested the BCIs in humans and that it aims to do so by the end of 2022. 

   

    Another article by Cade Metz (Metz, 2017) in the New York Times, discusses the uses of brain-reading devices in the broad market, apart from just bettering the life quality of people with paralysis. The author describes a game at its prototype stage, called “Awakening,” created by a company called Neurable. The game uses EEG technology to enable the player to navigate through a room they must escape using only their thoughts. The game by Neurable faces limitation problems due to the EEG technology it uses to read brain activity. The article says, “Although (the EEG) sensors can read electrical activity from outside the skull, it is very difficult to separate the signal from the noise” (Metz, 2017). The creator has tried to minimize noise through algorithms that learn from the user’s behavior during a “calibration” stage in the beginning of the game, although that is not always possible to accomplish. Although the game is limited as to what the user can do, it is still one of the first indications that neurotechnology is up and coming, and as Dr. Boyden from the M.I.T. Media Lab states, “Neurotechnology has become cool” (Metz, 2017).  Parts of the market are hoping to incorporate in their existing technology brain-reading devices that track chemical changes from outside the skull. Facebook, for example, would like to use such technology to help users type by thinking. On the other hand, neuroscientists are not sure whether something like that could be achieved without implants inside the skull. Furthermore, the article, like the one from Nature and the one from the Insider, also talks about Elon Musk and his ambition to use and implant Neuralink’s devices not only to improve the lives of people with paralysis but also to connect people with no health problems to machines. People from the field have two views on the matter of doing brain surgery to someone who does not need it (aka fully functioning people). Some, believe that it is something that could be done in the future, but we should approach it with caution so that it is incorporated into the market as “a kind of brain augmentation” (Metz, 2017). Others, such as Dr. Angle from the company Paradromics, states that, “In the physical sciences, there are physical boundaries. To think that you will be able to blow through fundamental laws by sheer ambition and enthusiasm is naïve” (Mertz, 2017). 

    

    In conclusion, we have talked about how brain-reading devices have evolved over time after a lot of research and funding. We also discussed how the technology from this research can be extremely beneficial to people that are unable to move, or communicate, as it gives them some form of independence by enabling them to do something they could not previously do. In addition, we looked over the different ambitions of different companies regarding brain-reading technologies. Some companies are viewing BCIs as an opportunity to benefit people in need of it, whereas others, like Neuralink, have goals that include the use of the implants to connect people with everyday used electronic devices and machines (aka phones, smartwatches, computers, cars). Finally, we touched on how neurotechnology is something that the market wants and is probably something that will be used more broadly in the future. Despite the enthusiasm and the benefits that come with neurotechnology/BCIs/ brain-reading devices, it is important to think about the ethics behind commercializing such technology. The article from Nature by Liam Drew (Drew, 2022) reminds the reader that the user’s privacy would be compromised, their every thoughts would be attained in the form of data by the companies owning the devices, in addition to the technology being able to get hacked.

 

Drew, L. (2022, April 20). The brain-reading devices helping paralysed people to move, talk and touch. Nature News. Retrieved May 2, 2022, from https://www.nature.com/articles/d41586-022-01047-w 

Kay, G. (2022, April 25). Elon Musk says Neuralink's brain chip will be 'similar in complexity level to Smart watches'. Business Insider. Retrieved May 2, 2022, from https://www.businessinsider.com/elon-musk-neuralink-brain-chip-similar-complexity-smartwatch-2022-4 

Metz, C. (2017, August 27). A game you can control with your mind. The New York Times. Retrieved May 2, 2022, from https://www.nytimes.com/2017/08/27/technology/thought-control-virtual-reality.html?searchResultPosition=3 

 

Using rTMS to Treat Refractory Epilepsy

     I have recently read an article about a study performed by Dr. Pavon and colleagues who investigated the emerging use of neuromodulation in the form of noninvasive electromagnetic brain stimulation (Dr. Pavon et al, 2019). Dr. Pavon and colleagues looked at a technique known as Transcranial Magnetic Stimulation (TMS) and its usage in stroke rehabilitation by delivering a time-varying pulse that is delivered to the brain (Dr. Pavon et al, 2019). This pulse is delivered by a coil that induces an electric field in the cortex and this produces neuronal activation when pyramidal cells and inhibitory interneurons are depolarized; Repetitive Transcranial Magnetic Stimulation (rTMS) occurs when a train of pulses is delivered to the brain and produces persistent effects (Dr. Pavon et al, 2019). Within the article, Dr. Pavon and colleagues explain that the rTMS is used after a stroke based on the inhibition model whereby excitability in the affected hemisphere is reduced and excitability in the unaffected hemisphere is increased (Dr. Pavon et al, 2019).  The results found that after the rTMS had been delivered to the affected hemisphere it increase cortical excitability and therefore improve motor functions following a stroke (Dr. Pavon et al, 2019). After reading this article I began to wonder if it would be possible to use rTMS as an implantation device or other to help regulate neuronal activation in individuals with epilepsy. A study performed by Dr. Shon, Dr. Lim, and Dr. Lim investigated the effects of low-frequency rTMS on non-lesional focal refractory epilepsy, meaning that for many of these patients medicine does not help to bring their seizures under control (Dr. Shon et al, 2019). The investigation consisted of four patients that received a daily dose of 900 pulses of .5 Hz stimulation for 10 days over the epileptic foci (Dr. Shon et al, 2019). Dr. Shon and colleagues measured seizure reduction which had been measured at baseline (4 weeks), intervention (2 weeks), and follow-up (8 weeks). The results showed that patients 2,3, and 4 showed reductions in seizures, however; patient 1 did not show any reduction in seizures (Dr. Shon et al, 2019). The use of rTMS for patients that suffer from refractory epilepsy reduced the weekly rate of seizures by 75% and this persisted after the 8-week follow-up (Dr. Shon et al, 2019). Both Dr. Pavon’s and Dr. Shon's articles indicate that future researchers could possibly use rTMS or TMS to help stroke patients as well as patients with epilepsy. I think further research and exploration on the use of TMS and rTMS would be beneficial for many people in the future and should be further pursued in hopes of helping to alleviate some of the obstacles that patients with epilepsy face.

Works Cited

Dr. Pavon et al, “Noninvasive Transcranial Magnetic Brain Stimulation in Stroke.” Phys Med, vol. 30,

2019, pp. 319-335. https://doi.org/10.1016/j.pmr.2018.12.010

 

Dr. Shon et al, “Therapeutic effect of repetitive transcranial magnetic stimulation on non-lesional focal

refractory epilepsy.” Clinical Neuroscience, vol. 63, 2019, pp. 130-133.

https://doi.org/10.1016/j.jocn.2019.01.025

Don’t Overthink It: Could Higher Executive Functions Inhibit Foreign Language Ability?

It is well known that children are much better at learning languages than adults. After all, it is exceedingly rare for one to master a language to the extent of one’s native one, thinking and dreaming in one learned later in life. Nelson Mandela famously said, “If you talk to a man in a language he understands, that goes to his head. If you talk to him in his language, that goes to his heart.”

One paper sought to compile research on this very topic, finding many interesting details about bilingualism and brain development (Berken et al., 2017). One such finding is that the first few months are crucial in phoneme (the sounds of a language) acquisition, and that the speaking of various sounds and babbles in a tongue that will grow to be indistinguishable to that of a native speaker solidify as early as one year of age.

The exact reason that humans lose this ability to take on a new language like our native one is unknown, and there are many possible explanations. One may be simple necessity and opportunity, that as infants we both require learning the language around us to communicate basic needs and have little else to do or devote brain power towards. A common theory is that young children’s minds are especially malleable, and that the increased neuroplasticity that comes with youth is why learning languages becomes increasingly difficult as one ages.

A recent study, however, hints at an entirely different conclusion. The University of Liverpool conducted a study that focused on the language ability of non-native speakers, comparing sober participants to those who consumed a low-dose of alcohol (Renner et al., 2017). Surprisingly, despite controlling for a placebo effect and finding no change in self-reported language ability, native speakers of the language in question blindly tended to rate those in the alcohol consuming group with significantly higher conversational scores!

This surely came as a surprise. Alcohol is well-known for inhibiting what are known as ‘executive functions’, things such as memory, attention, comprehension, alertness, and pronunciation. This is why we picture a forgetful, sleepy, inattentive, slurring person when we imagine somebody who has had a lot to drink. While the study was notably a small amount of alcohol- comparable to a pint of beer for an average man- it seems counterintuitive that even slight inhibition of the previously mentioned functions would result in better performance in speaking a foreign language. Many of the things we consider ‘executive functions’ are things we consider key to speaking a learned language. What could be the cause of this finding?

The study admittedly offers that the anxiety suppressing effects of alcohol could be the source of the findings. A small amount of alcohol tends to make most people more social and less nervous, which could have resulted in more casual and natural language. While this is likely partially to blame for the findings, I suggest something else. That the suppression of these executive functions is precisely what allows for better language abilities rather than being a side-effect that is overcome by alcohol’s more social effects.

While it’s true that memory recall and pattern recognition are what comes to mind when we think about a foreign language, it’s important to recognize that it may not be that way for an infant- those most adept at learning languages of all humans (broadly). An infant is not an acute pattern recognizing and alert genius; they wield a still developing brain that even at its best is much less intelligent than a heavily intoxicated adult. The mentioned study implies that partially inhibiting these executive functions allows the human mind to take a step closer to its natural language-learning state; more of a blank canvas than refined machinery.

It’s hard to say what this could mean for the future of language education and instruction if these findings are supported, particularly if the anxiety reducing effects of alcohol can be controlled for. Should students in high-school Spanish take a shot of vodka before their lesson? No, probably not. But it is worth exploring the fact that the logical, pattern based method with which we teach and learn languages is very different from how an infant naturally learns, and that a more immersive, less analytical method may lead to better and faster results. Maybe it’s time we started learning with our hearts instead of our heads. But maybe it also means that shotgunning a White Claw before your next foreign language final isn’t as bad of an idea as it might seem.

References

Berken, J. A., Gracco, V. L., & Klein, D. (2017). Early bilingualism, language attainment, and brain development. Neuropsychologia, 98, 220-227. https://doi.org/10.1016/j.neuropsychologia.2016.08.031

Renner, F., Kersbergen, I., Field, M., & Werthmann, J. (2017). Dutch courage? Effects of acute alcohol consumption on self-ratings and observer ratings of foreign language skills. Journal of Psychopharmacology, 32(1), 116-122. https://doi.org/10.1177/0269881117735687

Can Bilingualism Prevent Age-Related Cognitive Decline?

Historically, the average human life expectancy has experienced an upwards trend. Around the world, life expectancy has increased by an average of 6 years between 2000 and 2020. As this value increases, the issue of age-related diseases becomes more prominent and more critical to deal with in our society. As of now, there are 6 million Americans living with Alzheimer’s, and this number is expected to reach 13 million by 2050. In 2020, there were 930,000 people diagnosed with Parkinson’s, and by 2030 this number is expected to reach 1,200,000. As average life expectancy increases, the number of people with degenerative diseases will also increase. As we have not yet been able to find pharmaceutical solutions to disorders like this, it is of utmost importance that we find ways to increase cognitive reserve and prevent age-related cognitive decline. Although there are many methods of increasing cognitive reserve, such as exercise,hobbies,and games, recently more and more research is demonstrating that bilingualism has a role in ameliorating cognitive reserve by increasing activity and  connectivity between brain regions.

In our neuroscience class, we read Dr Berken’s research paper, “Early bilingualism, language attainment, and brain development”. This paper discusses the neuroplasticity that occurs in the brain as a result of simultaneous and sequential bilingualism. The two groups discussed in this paper are simultaneous and sequential English and French speakers in Montréal, Canada. It was found that simultaneous bilinguals had increased connectivity between several brain areas when compared to sequential bilinguals, implying that the later the age of acquisition is, the less communication there can be between different brain areas. Using resting-state fMRI, he found that simultaneous bilinguals had “greater connectivity between the left and right inferior frontal gyrus (IFG), as well as between the IFG and the brain areas involved in language control”. Berken also reports that both groups activated the same brain areas during a test for speech production that involved reading aloud, but the sequential bilinguals had increased activation in several different brain areas when reading aloud in their second language. Berken concludes that the later a language is learned, the more active the brain will become in activities such as speaking and reading, whereas learning a language earlier results in less brain activity due to the increased connectivity between brain regions. 

The article “Add Bilingualism to the Mix: L2 Proficiency Modulates the Effect of Cognitive Reserve Proxies on Executive Performance in Healthy Aging” by Gallo et al investigates how bilingualism can develop cognitive reserve. Cognitive reserve is essentially how well the brain can adapt to using alternative methods and modes of operation when faced with obstacles. Greater cognitive reserve means that an individual has a better chance at compensating for symptoms of neurodegenerative diseases such as multiple sclerosis, dementia, and Parkinson’s, and it also means that the individual can function better when exposed to unexpected stressful circumstances. This study was performed in an online format using cognitively healthy bilingual adults age sixty and above. Researchers found that bilingualism was a strong contribution to the development of cognitive reserve, claiming that it “plays an important role in mitigating cognitive decline and promoting successful aging”. The results of this study also report that “bilingualism supports the maintenance of optimal executive performance during senescence”. Although this study does not differentiate between sequential and simultaneous bilinguals, it still demonstrates that the increased activity in bilingual brains leads to an overall enhanced “executive network capacity, efficiency, and flexibility”. 

All in all, living in a society where the average life expectancy is constantly increasing also means that the number of age-related cognitive decline disorders is also concurrently rising. These numbers are rising faster than researchers and scientists are able to find pharmaceutical ways of managing and curing disorders like Parkinson’s, Alzheimer’s, and multiple sclerosis, meaning that we must look at other, non-pharmacological methods of battling these diseases. Learning a new language is one simple way of increasing brain activity, synaptic plasticity, and cognitive reserve. 

Works cited

Berken, Jonathan A., et al. “Early Bilingualism, Language Attainment, and Brain Development.” Neuropsychologia, Pergamon, 1 Sept. 2016, https://www.sciencedirect.com/science/article/pii/S0028393216303293. 

Gallo, Federico, et al. “Add Bilingualism to the Mix: L2 Proficiency Modulates the Effect of Cognitive Reserve Proxies on Executive Performance in Healthy Aging.” Frontiers in Psychology, Frontiers Media S.A., 31 Jan. 2022, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8841471/. 

“What Is Cognitive Reserve?” Harvard Health, 21 Sept. 2020, https://www.health.harvard.edu/mind-and-mood/what-is-cognitive-reserve

Bilingualism Delay of Dementia

Bilingualism Delay of Dementia 

            As the population of elderly people grow, dementia, Alzheimer’s disease, and other neurodegenerative disorders have become more prevalent. While there is no current pharmacological cure, nonpharmacological approaches including cognitive stimulation, diet, and physical activity has been used a preventative measure. Research has shown that older people who engage in activities such as reading and playing board game are less likely to experience memory loss associated with dementia (Kim et al., 2019). These activities stimulate the brain and in turn strengthen neural connections. The way the brain responds and adapts to environmental stimuli is known as neuroplasticity.  Neuroplasticity allows the brain to change shape and function to be more efficient in neural connections after stimuli.

            In the paper “Bilingualism for Dementia: Neurological Mechanisms Associated with Functional and Structural Changes in the Brain” (Kim et al., 2019), the authors explore the relationship between bilingualism and dementia. In this study, bilingualism serves an advanced form of cognitive stimulation that has been shown to delay the symptoms of dementia by approximately four to five years. For the brain to learn a second language, new neural connections and structures are formed to allow the brain to manage phonology, semantics, syntax, and grammar of a new language. This high-level brain activity is shown to maintain adult neurogenesis and helps to improve learning. Researchers have identified the subventricular zone to be a potential source of the cells for brain restoration (Kim et al.,). In addition, it shown that older bilingual people, compared to monolinguals, perform better on cognitive tasks. The formation of new synapses, increased axonal growth in granule neurons, and synaptogenesis in the hippocampus are all indicative of learning. These newly formed synapses, formed by learning two languages, compensates for those that become damaged during aging and dementia. Their research also shows that there is an increased functional connectivity in between Broca’s area, Wernicke’s area, dorsolateral prefrontal cortex, dorsal anterior cingulate cortex, and subcortical regions that is associated with bilingualism (Kim et al., 2019). Bilingualism can also help to delay symptoms of dementia by protecting the white matter tracts. As humans age, the density of gray matter is greater reduced in the sensorimotor areas, hippocampus, and entorhinal cortex. Bilingualism increases gray matter density in anterior cingulate cortex, basal ganglia, left caudate, and left putamen (Kim et al., 2019). This could prove as another mechanism to why learning a second languages helps to delay the onset of dementia, Alzheimer’s disease, or other neurodegenerative disorders. 

In Dr. Berken’s paper, “Early bilingualism, language attainment, and brain development” (Berken et al., 2017) the researchers further explore the connection between neuroplasticity and bilingualism. Differently than Dr. Kim’s study, Dr. Berken and his colleagues defined bilingualism to be a mastery of two language to a high proficiency. They studied three different groups: English monolinguals, sequential bilinguals, and simultaneous bilinguals. Like Dr. Kim’s study, they found that the sequential bilinguals who had a better accent had greater gray matter density in their left putamen. They found that when sequential bilinguals were speaking their second language, there was higher activation in the premotor cortex, inferior frontal gyrus, and fusiform gyrus. They also discovered a positive correlation between age of acquisition of second language and BOLD fMRI signals. The later the second language was learned, the more activation there is in the premotor area, inferior frontal gyrus, and fusiform gyrus. Dr. Berken and his colleagues concluded that simultaneous bilinguals, those who learned two languages from a very early age, have an increased functional connectivity that requires minimal neural effort to speak in either language. Their BOLD signals in an fMRI look very similar to the English monolinguals when they are speaking English. They also concluded that sequential bilinguals have brain organization that is indicative to learning changes later in life. Both sequential and simultaneous bilinguals provide evidence of neuroplasticity, just is different ways. 

Overall, bilingualism encourages advanced learning, cognitive stimulation, and neuroplasticity that can help reduce or delay the effects of aging and symptoms of neurodegenerative disorders.

 

 

 

References

Berken, J. A., Gracco, V. L., Klein, D. (2017). Early bilingualism, language attainment, and brain development. Neuropsychologia. https://www.sciencedirect.com/science/article/abs/pii/S0028393216303293

Kim, S., Jeon, S. G., Nam, Y., Kim, H. S., Yoo, D. H., & Moon, M. (2019). Bilingualism for Dementia: Neurological Mechanisms Associated With Functional and Structural Changes in the Brain. Frontiers in neuroscience, 13, 1224. https://doi.org/10.3389/fnins.2019.01224