• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
  • Skip to footer

Bowdoin Science Journal

  • Home
  • About
    • Our Mission
    • Our Staff
  • Sections
    • Biology
    • Chemistry and Biochemistry
    • Math and Physics
    • Computer Science and Technology
    • Environmental Science and EOS
    • Honors Projects
    • Psychology and Neuroscience
  • Contact Us
  • Fun Links
  • Subscribe

Science

Caution in STEM: Inhibition, Intuition, and Counterintuitive Reasoning

December 3, 2023 by Richard Lim '27

Imagine you’re on a 1950s game show. The host presents three doors and lays out the rules: Behind one door is a car, and behind the other two are goats. After you choose a door, the host, knowing what’s behind each door, opens one of the remaining two doors, revealing a goat. You have the opportunity to switch. Do you?

This is, of course, the infamous Monty Hall problem. Assuming you prefer the car over the goat, the answer is to always switch, since it will give you double the probability—⅔ rather than ⅓—of winning the car. Here’s an explanation that goes through each possible case (Table 1):

Table 1: Possible outcomes for staying and switching in the Monty Hall problem (Saenen et al., 2018)

If you got it wrong, you’re not alone—between 79% and 87% of adults get it wrong, too (Saenen et al., 2018). But what is behind this phenomenon? Solving unintuitive problems like the Monty Hall problem is thought to require the inhibition of misleading information, such as from prior knowledge or false cues (Dumontheil et al., 2022; Saenen et al., 2018). However, a 2018 study by Brookman-Byrne et al. and a 2022 study by Dumontheil et al. shine a new, more nuanced light on the connection between inhibitory control and (counter)intuition.

Both studies had British schoolchildren aged 11-15 undergo a volley of tests assessing their response inhibition (the ability to manage and filter out conflicting information), semantic inhibition (the ability to suppress responses driven by impulse ), vocabulary, reasoning, and working memory. Researchers then had participants complete a set of intuitive (control) and counterintuitive math and science problems. Dumontheil et al. (2022) measured neural activity using fMRI (functional Magnetic Resonance Imaging, an imaging technique which measures blood-oxygen levels to determine which parts of the brain are active) throughout.

Unsurprisingly, researchers consistently found that participants were more accurate and faster in solving intuitive problems than counterintuitive problems. Furthermore, in counterintuitive reasoning, response inhibition predicted response times, whereas semantic inhibition predicted accuracy. Interestingly, however, the only predictors of counterintuitive reasoning ability found in both studies were a more extensive vocabulary and increased age, both of which also predicted response inhibition (Brookman-Byrne et al., 2018; Dumontheil et al., 2022). Given these unexpected findings, neuroimaging results by Dumontheil et al. (2022) were necessary to provide some insight into what goes on in participants’ brains. 

Figure 1: Brain regions showing greater activation for (A) counterintuitive versus control (intuitive) problems, (C) response inhibition versus no response inhibition, and (D) semantic inhibition versus no semantic inhibition (Dumontheil et al., 2022). 

Figure 2: A comparison between areas showing increased activation during counterintuitive reasoning and (A) complex inhibition behavior, and (B) interference control behavior (Dumontheil et al., 2022). 

Since the overlap is limited in Figure 2, researchers concluded that the relationship between inhibitory control and counterintuitive problem solving was not direct (Dumontheil et al., 2022). They posit that the role of inhibition in counterintuitive reasoning may be limited to specific types of inhibition. In particular, semantic inhibition might be a better explanation than just response inhibition (Dumontheil et al., 2022). 

Neurosynth (an fMRI image database) also associates areas activated during counterintuitive reasoning with “working memory,” “calculation,” “symbolic,” “attention,” “visually,” and “spatial,” suggesting that inhibition is not the only factor at play (Dumontheil et al., 2022). They highlight that two areas known as the intraparietal sulcus (IPS) and Brodmann area 7 (BA 7)—which together are responsible for visuo-spatial attention—show increased activation during counterintuitive reasoning, response inhibition, and semantic inhibition (Dumontheil et al., 2022). Hence, they also suggest that visuo-spatial attention may be another factor in counterintuitive reasoning (Dumontheil et al., 2022). 

So what does this mean, practically? For educators, it seems that curriculum design in STEM should not be done in isolation. Given the impact of semantic reasoning, it would be prudent to balance training in purely symbolic reasoning with training in semantic reasoning (e.g., by requiring humanities classes be taken with STEM classes). For cognitive neuroscientists, this research suggests that there may be another dimension to understanding counterintuitive reasoning: the complex causal relationships between visuo-spatial attention, inhibitory control, and counterintuitive reasoning. Indeed, this is a cautionary tale about the importance of inhibition in science itself—causation is difficult to establish, and the most intuitive models in science may not always be right, either.

 

References

Brookman-Byrne, A., Mareschal, D., Tolmie, A. K., & Dumontheil, I. (2018, June 21). Inhibitory control and counterintuitive science and maths reasoning in adolescence. PLoS ONE, 13(6), 1-19. https://doi.org/10.1371/journal.pone.0198973

Dumontheil, I., Brookman-Byrne, A., Tolmie, A. K., & Mareschal, D. (2022). Neural and Cognitive Underpinnings of Counterintuitive Science and Math Reasoning in Adolescence. Journal of Cognitive Neuroscience, 34(7), 1205. https://doi.org/10.1162/jocn_a_01854

Saenen, L., Heyvaert, M., Van Dooren, W., Schaeken, W., & Onghena, P. (2018). Why Humans Fail in Solving the Monty Hall Dilemma: A Systematic Review. Psychologica Belgica, 58(1), 128-158. https://doi.org/10.5334/pb.274

 

Filed Under: Math and Physics, Psychology and Neuroscience, Science Tagged With: cognitive, education, fMRI, math, Psychology and Neuroscience, science

ChatGPT Beats Humans in Emotional Awareness Test: What’s Next?

December 3, 2023 by Nicholas Enbar-Salo '27

In recent times, it can seem like everything revolves around artificial intelligence (AI). From AI-powered robots performing surgery to facial recognition on smartphones, AI has become an integral part of modern life. While AI has affected nearly every industry, most have been slowly adapting AI into their field while trying to minimize the risks involved with AI. One such field with particularly great potential is the mental health care industry. Indeed, some studies have already begun to study the uses of AI to assist mental health work. For instance, one study used AI to predict the probability of suicide through users’ health insurance records (Choi et al., 2018), while another showed that AI could identify people with depression based on their social media posts (Aldarwish & Ahmed, 2017). 

Perhaps the most wide-spread AI technology is ChatGPT, a public natural language processor chatbot that can help you with a plethora of tasks, from writing an essay to playing chess. Much discussion has been done about the potential of such chatbots in mental health care and therapy, but few studies have been published on the matter. However, a study by Zohar Elyoseph has started the conversation of chatbots’ potential, specifically ChatGPT, in therapy. In this study, Elyoseph and his team gave ChatGPT the Levels of Emotional Awareness Scale (LEAS) to measure ChatGPT’s capability for emotional awareness (EA), a core part of empathy and an essential skill of therapists (Elyoseph et al., 2023). The LEAS gives you 20 scenarios, in which someone experiences an event that supposedly elicits a response in the person in the scenario, and the test-taker must describe what emotions the person is likely feeling. Two examinations of the LEAS, one month apart, were done on ChatGPT to test two different versions of ChatGPT. This was done to see if updates during that month would improve its ability on the LEAS. On both examinations, two licensed psychologists scored the responses from ChatGPT to ensure reliability of its score. On the first examination in January 2023, ChatGPT achieved a score of 85 out of 100, compared to the French men’s and female’s averages of 56.21 and 58.94 respectively. On the second examination in February 2023, ChatGPT achieved a score of 98: nearly a perfect score, a significant improvement from the already high score of 85 a month prior, and a score that is higher than most licensed psychologists (Elyoseph et al., 2023).

This study shows that, not only is ChatGPT more capable than humans at EA, but it is also rapidly improving at it. This has massive implications for in-person therapy. While there is more to being a good therapist than just emotional awareness, it is a major part of it. Therefore, based on this study, there is potential for chatbots like ChatGPT to rival, or possibly even replace, therapists if developers are able to develop the other interpersonal traits of good therapists. 

However, ChatGPT and AI needs more work to be done before it can really be implemented into the mental health field in this manner. To start, while AI is capable of the technical aspects of therapy, such as giving sound advice and validating a client’s emotions, ChatGPT and other chatbots sometimes give “illusory responses”, or fake responses that it claims are legitimate (Hagendorff et al., 2023). For example, ChatGPT will sometimes say “5 + 5 = 11” if you ask what 5 + 5 is, even though the answer is clearly wrong. While this is a very obvious example of an illusory response, harm can be done if the user is not able to distinguish between the real and illusory responses for more complex subjects. These responses can be extremely harmful in situations such as therapy, as clients rely on a therapist for guidance, and if such guidance were fake, it could harm rather than help the client. Furthermore, there are concerns regarding the dehumanization of therapy, the loss of jobs for therapists, and the breach of a client’s privacy if AI was to replace therapists (Abrams, 2023). ​​

Fig 1. Sample conversation with Woebot, which provides basic therapy to users. Adapted from Darcy et al., 2021. 

However, rudimentary AI programs are already sprouting that try to bolster the mental health infrastructure. Replika, for instance, is an avatar-based chatbot that offers therapeutic conversation with the user, and saves previous conversations to remember them in the future. Woebot provides a similar service (Figure 1), providing cognitive-behavioral therapy (CBT) for anxiety and depression to users (Pham et al., 2022). While some are scared about applications such as these, these technologies should be embraced since, as they become more refined, they could provide a low-commitment, accessible source of mental health care for those who are unable to reach out to a therapist, such as those who are nervous about reaching out to a real therapist, those who live in rural environments without convenient access to a therapist, or those who lack the financial means for mental health support. AI can also be used as a tool for therapists in the office. For example, an natural language processing application, Eleos, can take notes and highlight themes and risks for therapists to review after the session (Abrams, 2023). 

There are certainly some drawbacks of AI in therapy, such as the dehumanization of therapy, that may not have a solution and could therefore limit AI’s influence in the field. There is certainly a chance that some people would never trust AI to give them empathetic advice. However, people said the same when robotic surgeries began being used in clinical settings, but most people seem to have embraced that due to its superb success rate. Regardless of whether these problems are resolved, AI in the mental health industry has massive potential, and we must make sure to ensure that the risks and drawbacks of such technology are addressed and refined so that we can make the most of this potential in the future and bring better options to those who need it. 

 

Citations

Abrams, Z. (2023, July 1). AI is changing every aspect of psychology. Here’s what to watch for. Monitor on Psychology, 54(5). https://www.apa.org/monitor/2023/07/psychology-embracing-ai

 

Aldarwish MM, Ahmad HF. Predicting Depression Levels Using Social Media Posts. Proc – 2017 IEEE 13th Int Symp Auton Decentralized Syst ISADS 2017 2017;277–80.

 

Choi SB, Lee W, Yoon JH, Won JU, Kim DW. Ten-year prediction of suicide death using Cox regression and machine learning in a nationwide retrospective cohort study in South Korea. J Affect Disord. 2018;231(January):8–14.

 

Darcy, Alison & Daniels, Jade & Salinger, David & Wicks, Paul & Robinson, Athena. (2021). Evidence of Human-Level Bonds Established With a Digital Conversational Agent: Cross-sectional, Retrospective Observational Study. JMIR Formative Research. 5. e27868. 10.2196/27868. 

 

Elyoseph, Z., Hadar-Shoval, D., Asraf, K., & Lvovsky, M. (2023). ChatGPT outperforms humans in emotional awareness evaluations. Frontiers in psychology, 14, 1199058. 

 

Hagendorff, T., Fabi, S. & Kosinski, M. Human-like intuitive behavior and reasoning biases emerged in large language models but disappeared in ChatGPT. Nat Comput Sci 3, 833–838.

 

Pham K. T., Nabizadeh A., Selek S. (2022). Artificial intelligence and chatbots in psychiatry. Psychiatry Q. 93, 249–253.



Filed Under: Computer Science and Tech, Psychology and Neuroscience, Science Tagged With: AI, AI ethics, ChatGPT, therapy

PedPRM Unveils Promising Treatment for Insomnia in Children with Autism Spectrum Disorder

December 3, 2023 by Fabiola Barocio Prieto

Getting enough sleep is widely considered crucial to our well-being. However, for some individuals with Autism, getting enough quality sleep is not as easy as it sounds. Autism Spectrum Disorder (ASD) is a developmental disorder that widely affects the U.S. population, as 1 in 36 children aged eight has been diagnosed with autism (CDC, 2023). The kind and severity of the symptoms that individuals with ASD may exhibit can vary along the ASD spectrum.  Sleeping, in particular, is a common challenge for those with ASD, as many suffer from problems related to the REM (Rapid Eye Movement) sleep phase, a phase critical for memory consolidation (Devnani & Hedge, 2015). This can quickly become a vicious cycle for some, as lack of sleep can increase the severity of other Autism-related symptoms but also affect both the individual and the quality of life of their family or caretakers. 

To investigate possible treatments, a recent study by Malow et al. focuses on the pharmacological approach of using melatonin to treat sleep disorders. Melatonin is a hormone produced by the body’s pineal gland to regulate circadian rhythm, allowing the body to relax according to the appropriate light-darkness cycles of the day. This study uses a small, long-release tablet (PedPRM) used to mimic endogenous melatonin secretion. It focused mainly on a younger population, from children to adolescents, who met two criteria. The first was that they had confirmed diagnoses of either Autism or Smith-Magenis syndrome and had also experienced sleep abnormalities. Smith-Magenis syndrome is also a developmental disorder that involves symptoms similar to those of ASD, affecting behavior, cognition, and sleep. They also had to have not previously seen improvements when using sleep hygiene treatments to be included in the study, such as establishing a strict bedtime routine and taking steps to provide a calm and comfortable sleep environment (CHOC, 2023).

With the study sample set, the study was conducted over 108 weeks and divided into four phases (Graph I). Throughout the four phases, participants’ caregivers would document sleep quality and total sleep time in a sleep and nap diary to record the efficacy of treatment. The study participants started the first stage with a 2-week period in which they were given placebos. If participants showed improvement while receiving a placebo, they would be removed from the study to reduce the possibility of external factors affecting the results (Scott et al., 2021). After clearing Phase 1, participants entered the second phase, which consisted of a double-blinded 13-week period in which they were randomly placed into either a placebo or treatment group (PedPRM). After this, Phase 3 comprised a longer 91-week open-label period in which both groups were combined. For the final phase of the study, participants were placed again in a 2-week single-blind placebo period to ensure that the drug had been completely removed from the participants with no adverse effects after stopping treatment.

Upon concluding the experimental period, the results to be considered for this study could be divided into three groups: participants’ sleep quality, caregivers’ well-being, and the participants’ growth development. With this data, the researchers found a significant

 decrease in sleep disturbance (Graph II-A) and an increase in caregiver satisfaction (II-B) and quality of life (II-C). These were most pronounced during the first half of the treatment. In the latter half of treatment, sleep disturbance continued to decrease but at a slower pace than the initial treatment phase. Fortunately, there were no reported deaths, and most adverse reactions included daytime fatigue and mood swings. However, the severity and extent of these were not detailed in the results of the study and offer the potential to be analyzed further.  

The study shows compelling initial evidence that PedPRM is an effective treatment for sleep disorders in individuals with ASD. However, as noted by the researchers, it also shows that constant active treatment is required as most sleep quality improvements are removed upon halting treatment. Since medications for children are generally more strictly controlled, PedPRM consistently demonstrates a possibility for effective pediatric treatment, even if for long-term medication. In particular, these findings are essential as it has been found that rapid-release melatonin is not helpful with maintaining sleep a couple of hours after administration, and it had long been considered a challenge to find small, swallowable prolonged-release tablets for children (Fliesler, 2022). As sleep interruption is something that mainly affects those with neurodevelopmental disorders, this is a significant step towards adequate treatment. However, it is essential to note that this pharmacological alternative should only be considered if behavioral interventions and sleep hygiene modifications have been attempted but have been found unsuccessful. 

 

 

Sources 

CDC. (2022, December 9). Centers for Disease Control and Prevention. https://www.cdc.gov/ncbddd/autism/facts.html 

CDC Newsroom. (2016, January 1). CDC. https://www.cdc.gov/media/releases/2023/p0323-autism.html 

CHOC – Children’s Hospital of Orange County. (2023, March 2). Autism and Sleep Hygiene – Children’s Hospital of Orange County. Children’s Hospital of Orange County. https://www.choc.org/programs-services/autism-neurodevelopmental/co-occurring-conditions-program/autism-and-sleep/ 

Devnani, P., & Hegde, A. U. (2015). Autism and sleep disorders. Journal of Pediatric Neurosciences, 10(4), 304. https://doi.org/10.4103/1817-1745.174438 

Fliesler, N. (2022, June 13). Melatonin for kids: Is it effective? Is it safe? – Boston Children’s Answers. Boston Children’s Answers. https://answers.childrenshospital.org/melatonin-for-children/#:~:text=There%20is%20some%20evidence%20to,the%20ability%20to%20swallow%20capsules. 

Furfaro, H. (2023, March 10). Sleep problems in autism explained. Spectrum | Autism Research News. https://www.spectrumnews.org/news/sleep-problems-autism-explained/ 

Lemoine, P., Garfinkel, D., Laudon, M., Nir, T., & Zisapel, N. (2011). Prolonged-release melatonin for insomnia – an open-label long-term study of efficacy, safety, and withdrawal. Therapeutics and Clinical Risk Management, 301. https://doi.org/10.2147/tcrm.s23036 

Malow, B. A., Findling, R. L., Schröder, C., Maras, A., Breddy, J., Nir, T., Zisapel, N., & Gringras, P. (2021b). Sleep, Growth, and puberty after 2 years of Prolonged-Release Melatonin in children with Autism Spectrum Disorder. Journal of the American Academy of Child and Adolescent Psychiatry, 60(2), 252-261.e3. https://doi.org/10.1016/j.jaac.2019.12.007 

Scott, A., Sharpe, L., Quinn, V. F., & Colagiuri, B. (2022). Association of single-blind placebo run-in periods with the placebo response in randomized clinical trials of antidepressants. JAMA Psychiatry, 79(1), 42. https://doi.org/10.1001/jamapsychiatry.2021.3204 

Signs & Symptoms | Autism Spectrum Disorder (ASD) | NCBDDD | CDC. (2023, January 11). Centers for Disease Control and Prevention. https://www.cdc.gov/ncbddd/autism/signs.html

Filed Under: Biology, Chemistry and Biochemistry, Psychology and Neuroscience, Science Tagged With: Autism, Medicine, sleep

Seeing Without Light: Measuring Megahertz-Frequency Vibration on the Atomic Scale

December 3, 2023 by Elliott Ewell

Scientists cannot take a picture of an atom. This is because visible light consists of waves so much larger than atoms that the two do not interact. Even supposed pictures of atoms, like this particularly famous one by British physicist David Nadlinger, show the radiation emitting from the atom – not the atom itself. So how else are we supposed to observe what happens at the atomic scale?

Vibration is an important key to link the quantum world with our own. Whereas visual observation is difficult on ultra-small scales, vibration still applies as a valid way to detect information. It’s like how you may be able to feel a splinter in your finger even though you can’t see it. For convenience, physicists often describe vibrations – periodic movement of atoms – as “phonons” (Chandler, 2010). Though phonons may sound like fundamental particles like protons or electrons, they aren’t. Phonons are just a way to describe complicated interactions between other fundamental particles into an easy-to-work-with particle form (Lewton, 2021). What we call heat is the same sort of approximation: it is an aggregate, easier way to describe the energy of the innumerable atoms in an object colliding like hundreds of billiard balls.

In Nature Physics, a team of researchers led by Caltech Professor Alkim Bozkurt recently created a device capable of reliably transforming phonons into detectable electromagnetic waves (2023). In their paper, published June of 2023, they describe an electrical circuit whose outputs vary with vibration.

Fundamental to the researchers’ design is a capacitor. Capacitors are circuit components that store electrical charges, i.e. electrons, on two parallel conducting plates separated by a small distance on their bodies. Capacitors are defined by their capacitance, which is the ability of a given component to hold charge. The key to Bozkurt et al.’s device is that capacitance depends on the distance between its parallel plates (2023). When the distance between the plates increases, capacitance decreases, and vice versa.

In the device described in the paper, Bozkurt et al. take advantage of capacitors’ properties to transmit photons (2023). The researchers connected the parallel plates of a calculator to a vibrating crystal lattice. When the lattice moves, the parallel plates – and thus capacitance –  change accordingly. Oscillating capacitance isn’t detectable on its own. However, voltage is a function of capacitance, and capacitance is the function of vibration. By hooking the capacitor up to a circuit whose output changes with voltage, we can observe the information carried by the phonons.

By hooking up the capacitor to a small transmitting circuit, the researchers can ascertain the phonons’ properties (Bozkurt et al., 2023). In operation, the wave transmitter must be tuned until the interaction between the moving capacitor and the transmitter creates a peak of detectable voltage in the transmitted wave. This peak occurs where the phonon frequency matches that of the transmitted microwave.

Say, for example, you have a crystal that vibrates at an unknown frequency 𝑓 that is greater than a millions of times per second. To find 𝑓, we attach the new device to the crystal. Then, once it begins vibrating, you must tune the transmitter’s electromagnetic wave output frequency to match the unknown 𝑓. When a peak of detectable voltage in the transmitted microwaves is observed, the output microwave frequency will equal to the unknown 𝑓. Thus, by measuring the microwaves, you will have indirectly measured the frequency of the vibrating crystal.

Such a device has practical applications well beyond measurement. The device can be used in parts of quantum memory units, interfacing with parts of quantum computers. It could effectively record the characteristic changes of a quantum system and then restore that state accordingly – something optical observing at such a small scale cannot achieve. Still, the invention is not quite able to match the phonon frequency as alternatives. Its outputs sometimes do not agree with the known vibration of the crystal. The paper cites possible next steps – including altering the transmitter – to increase its agreement with the known vibration of the phonons in testing (Bozkurt et al., 2023).

Still, this development is remarkable. The Caltech researchers produced a device that detects phonons at speeds of a billion times a second, orders of magnitude more sensitive than similar previous devices, with substantially improved reliability (Bozkurt et al., 2023). Other similar approaches rely on hard-to-create materials and suffer from short lifetimes at small scales.

Works Cited:

Bozkurt, A., Zhao, H., Joshi, C., LeDuc, H. G., Day, P. K., & Mirhosseini, M. (2022). A quantum electromechanical interface for long-lived phonons. Nature Physics, 19(September 2023), 1326–1332.

Brean, J. (2018, February 14). Stunning image of a single strontium atom wins British photography prize. https://nationalpost.com/news/world/stunning-image-of-a-single-strontium-atom

Chandler, D. L. (2010, July 8). Explained: Phonons. MIT News. https://news.mit.edu/2010/explained-phonons-0706

Lewton, T. (2021, March 24). The Near-Magical Mystery of Quasiparticles. Quantamagazine. https://www.quantamagazine.org/the-near-magical-mystery-of-quasiparticles-20210324/

 

 

Filed Under: Math and Physics, Science Tagged With: atoms, capacitor, circuit, coupling, crystal, interfacing, observation, phonons, quantum, vibration

Distributions, not Differentiation: New Studies Find Cell Proportions at the Heart of Neurological Specialization

December 3, 2023 by Vincent Chen '27

The human brain is organized into cortices, lobes, hemispheres, and more, with every designation serving as a location where a particular function necessary for survival is hosted. In understanding the cell types of the brain, scientists can further shape the understanding of the nature of human life. Current work strives toward comprehending the functions and capacities of the brain and developing stronger foundations for modeling brain physiology to support future research and medical applications. All of the advancements discussed originated from Alyssa Weninger and Paola Arlotta’s Science review article, A family portrait of human brain cells, which compiles recent findings in brain mapping research as aligned with the National Institute of Health’s BRAIN Initiative. In the article, Weninger and Arlotta summarize and discuss the work of multiple groups of neuroscientists that have developed new findings about the brain’s composition and variability across regions, individuals, and species (specifically five primates of interest and mice).

As suggested by the article, recent research from multiple teams of neuroscientists utilized a variety of study mechanisms to compare the composition of the brain. One of the most important tools used in the studies included single-cell profiling. This profiling technique analyzes cellular behavior through multiple methods that include their transcriptome (range of genetic information produced to control cell behavior), proteome (range of proteins produced by the cell), and epigenome (range of modifications and markings that control the genetic information expressed by a cell) to organize them into groups based on their functional similarities. Models that encompass these methods and human organoids (structures of organs derived from STEM cells that mimic organ tissue) are developed to model the brain and its cells. They are also used in mapping and developing comparative analyses to determine significant findings and understanding of the brain organization.

Comparisons of cell composition in regions across the brain resulted in findings from researchers under Siletti from the University of North Carolina at Chapel Hill and Jorstad from Harvard University. The two groups found that rather than mainly having different types of cells in different parts of the brain, some different parts of the brain shared the same cells but had different proportions of these cells. There were some exceptions, such as inhibitory neurons in the primary visual cortex, although the explanation of this finding is unclear. Such results change the understanding of evolutionary diversity in that diversification does not depend heavily on having many different cell types, but rather on having varying proportions of cells with small differences.

Jorstad’s group also developed a significant result in identifying differences in brain composition between human individuals. One cell type from 75 individuals was profiled and resulted in different classes of cells bearing contrasting levels of variability among individuals. Most of the explanatory factors were beyond demographic differences, such as gender, ancestry, or age. The reason for such differences is still unclear. Scientists are further encouraged to study bigger cohorts of people to further examine the origin of differences in variability across humans.

The finding of varying cell proportions held as Jorstad’s group conducted interspecies comparisons, comparing human compositions with other primates (specifically chimpanzees, gorillas, rhesus macaques, and marmosets). The exceptional cognitive ability found in humans was largely supported by differences in proportions of brain cell types rather than the variability of cell types. Additionally, faster evolutionary divergence may explain the differences in gene expression found between supportive tissue, known as glial cells, in the brain. This allowed for further species-specific development across primates. Only a limited number of gene patterns specific to humans were found, most of them concentrated in parts of the brain with human evolutionary change. As such, scientists have come to understand that attributes of the human brain are derived from very few cellular or molecular changes, leaving differences in cell proportions as the most prominent explanatory factory for human brain development. Furthermore, understanding the brains of related primates and their relation to human brains will help scientists develop new models for brain pathways and understand the kinds of questions that they will be able to answer with such knowledge in the future.

Neuroscientists today continue to work hard toward developing human brain models. Current studies are focusing on developing accurate organoids – three-dimensional tissue models of stem cells developed to mimic organs in structure and function. Velmeshev’s group of researchers worked towards profiling different cortical (outer layers of the upper brain) areas and related areas in fetuses to track developments across human births. Kim’s group of researchers investigated single-cell transcriptomes of the thalamus (the processor of sensory data) during its development but was missing an investigation of the thalamus cellular compositions. The work of these scientists contributes to the idea of molecular mechanisms as the driver of cellular diversity in the brain, but also calls for more innovation in external biological investigations to better model the brain and further study its composition. In doing so, neuroscientists will come even closer to understanding one of the most complex systems in the human body and develop more answers for current-day neurological problems.

Bibliography

Weninger, Alyssa, and Paola Arlotta. “A Family Portrait of Human Brain Cells.” Science, vol. 382, no. 6667, Oct. 2023, pp. 168–69, https://doi.org/10.1126/science.adk4857.

Filed Under: Psychology and Neuroscience, Science Tagged With: brain, brain cell proportions, BRAIN Initiative, mapping, models, profiling

mRNA: Unpacking the Research that led to the COVID-19 Vaccines and the 2023 Nobel Prize in Medicine

November 19, 2023 by Maren Cooper '27

        By 2023, 81.4% of the United States population have received at least one dose of the COVID-19 mRNA vaccine, and just about everyone has heard of these lifesaving shots (CDC, 2023). But how many of us actually know how they work? In general, vaccinations expose the body to a weakened strain of a virus that initiates an immune response so that the virus can be recognized, and quickly neutralized, in the future (Jain, 2021). This works because of the structure of our immune system, which is split up into innate immunity and adaptive immunity. Innate immunity is the immediate response that our bodies put up when exposed to a pathogen; it sends out macrophages to gobble up infected cells, creates an inflammatory response to kill off the infection, and uses a host of molecules and pathways to destroy the virus. Adaptive immunity involves the presence of B and T cells, which arise in a viral infection and create immunological memory through antibodies and memory cells so that a future infection of the same virus is immediately recognized and shut down. Vaccines work to stimulate this adaptive immunity, while minimizing innate immunity.

        mRNA vaccines use this same basic principle, but instead of injecting a weakened strain of the actual virus into someone, they instead inject a piece of mRNA, or messenger RNA, which codes for a viral protein that stimulates this immune response (Jain, 2021).

Figure 1: The methodology of mRNA vaccines. Adapted from Jain, et. al., 2021

mRNA vaccines are much easier to make than traditional vaccines because they don’t require growing and inactivating a virus, and they don’t carry the risk that live vaccines have of infecting the subject, but up until recently, they weren’t even remotely possible because in vitro mRNA would create a huge inflammatory response when entering the body (Karikó, 2005). However, Hungarian biochemist Katalin Karikó and her colleague Drew Weissman were undeterred, and their research to create mRNA without an inflammatory response paved the way for mRNA vaccines and won them the Nobel Prize in Medicine in 2023 (Karikó, 2005).

        Karikó and Weissman’s research focused on in vitro mRNA’s stimulation of Toll-like receptors (TLRs), which recognize pathogens and activate signaling pathways leading to an inflammatory response (Karikó, 2005). They discovered that mammalian mRNA, which doesn’t stimulate an immune response, contains many base pair modifications, whereas bacterial RNA, which is known to stimulate a response, has no modifications (Karikó, 2005). In vitro mRNA, grown in a lab rather than from mammalian cell cultures, also has no, or very few, modifications. This led the researchers to question whether base pair modifications were how cells distinguished between foreign and non-foreign RNA, and thus which pieces of RNA stimulate an immune response (Karikó, 2005). They discovered that in vitro RNA activates three main TLRs known for activating an inflammatory response, but that nucleoside modifications limit that activation. Most importantly, they discovered that the suppressed immune response is proportional to the number of nucleotide modifications, and that these modifications also increase the stability of in vitro mRNA in the body, another original roadblock in the usage of mRNA for vaccines. (Karikó, 2005).

Figure 2: The use of base modifications to suppress inflammatory response of RNA. Adapted from Nobelprize.org

        Combined with later research also by Karikó and Weissman discovering that modified base-pairs also create increased protein production and other research designing more stable lipid carriers to deposit the mRNA into human cells, mRNA became a promising new vaccine technology, eventually allowing the COVID-19 vaccines to be produced in record times, shortening the pandemic and granting all of us our lives back. But the road to Karikó’s research being recognized, and especially the road to the Nobel Prize, was not predetermined. Karikó’s research was long overlooked, in part because of her identity as a Hungarian immigrant. She was “demoted four times” at UPenn, being told that her research didn’t measure up to their standards, but she continued to persevere, making her both a scientific success story, and a personal one (Shrikant, 2023). The COVID-19 vaccines created by Pfizer and Moderna were the first mRNA vaccines to be released, but future research is focusing on creating a universal flu vaccine and possibly even an HIV vaccine, all using mRNA technologies, which could drastically improve the landscape of viral infections, both in the US and across the globe.  

 

Literature Cited

Karikó, K., Buckstein, M., Ni, H., & Weissman, D. (2005). Suppression of RNA Recognition by Toll-Like Receptors: The Impact of Nucleoside Modification and the Evolutionary Origin of RNA. Immunity, 23(2), 165–175. https://doi.org/10.1016/j.immuni.2005.06.008

 Karikó, K., Muramatsu, H., Welsh, F. A., Ludwig, J., Kato, H., Akira, S., & Weissman, D. (2008). Incorporation of Pseudouridine into mRNA yields Superior Nonimmunogenic Vector with Increased Translational Capacity and Biological Stability. Molecular Therapy, 16(11), 1833–1840. https://doi.org/10.1038/mt.2008.200

 Jain, S., Venkataraman, A., Wechsler, M. E., & Peppas, N. A. (2021). Messenger RNA-Based Vaccines: Past, Present, and Future Directions in the Context of the COVID-19 Pandemic. Advanced Drug Delivery Reviews, 179, 114000. https://doi.org/10.1016/j.addr.2021.114000

 The Nobel Prize in Physiology or Medicine 2023. (n.d.). NobelPrize.Org. Retrieved October 22, 2023, from https://www.nobelprize.org/prizes/medicine/2023/press-release/

 CDC. (2020, March 28). Covid Data Tracker. Centers for Disease Control and Prevention. https://covid.cdc.gov/covid-data-tracker

Shrikant, A. (2023, October 6). Nobel Prize Winner Katalin Karikó was “demoted 4 times” at her old job. How she persisted: “You have to focus on what’s next.” CNBC. https://www.cnbc.com/2023/10/06/nobel-prize-winner-katalin-karik-on-being-demoted-perseverance-.html 

 

Filed Under: Biology, Chemistry and Biochemistry, Science

Biomimicry Within Bowdoin: The Ongoing Development of Peptoids

April 4, 2023 by Anika Sen

To solve complex human health issues, scientists have more recently turned to biomimicry. Biomimicry, also known as biomimetics, is a field that develops synthetic materials, systems or machines that are derived from the principles of natural biological processes (Nature). Concepts within biomimetics are currently being used to design regenerative medicine and newer drugs for diseases such as cancer. In fact, within Bowdoin, Professor Benjamin Gorske, is undertaking a comprehensive research on developing methods to create drugs that attempt to inhibit signaling pathways within cancer, or interrupt the signal transduction pathways involved in the development of plaques in Alzheimer disease. 

Professor Gorske explains that these aforementioned diseases can be addressed by “controlling the signaling proteins”. By interrupting the signaling process, the underlying issue of these diseases – which are often so diverse and hard to target – doesn’t need to be treated. However, a difficulty that comes with targeting signaling proteins is that they bind to other molecules over a vast space, and are implicated in many other signaling pathways. Therefore, these proteins cannot simply be targeted by small molecular drugs, as they would be impossible to effectively block the proteins and thus are called “undruggable molecules”. Instead, Professor Gorske turns to attempting to create a biological molecule that can mimic the other molecules that bind to the target signaling protein – which are normally much bigger than current drug molecules. 

One of the targets that Professor Gorske looks into in his lab are the signaling proteins within the Hippo pathway. The Hippo pathway normally controls the size of organs by regulating cell proliferation (division of cells) and apoptosis (programmed cell death) (Cell Signaling Technology). Ultimately, this pathway controls the expression of certain genes that are involved in the proliferation process. This pathway is involved in cancer when it is disregulated, as it continuously sends a signal to the nucleus to express these genes encoding for cell proliferation, thus leading to the uncontrollable growth of cancer. The Hippo pathway involves a lot of signaling proteins that are solely involved in this signaling pathway. Most of these signaling proteins contain a WW domain – a distinct functional unit of the protein that mediates the interactions these proteins have with other molecules (EMBL-EBI). All the signaling proteins with this specific domain in this pathway generally bind to proteins with polyproline type 2 helices (PPII). Professor Gorske’s lab aims to design a molecule to contain this PPII structural component to effectively target the signaling proteins (with the WW domain) in the Hippo pathway.

Fig 1: Diagram of the Hippo Pathway. The signaling protein YAP (yes-associated protein/transcription coactivator) is an example of a molecule with the WW domain.

However, we can’t utilize naturally formed proteins with these PPII helices as the proteases in our body would find the related drugs as foreign and destroy them. Thus these helices need to be made artificially, forming molecules called peptoids. Peptoids are a class of molecules that mimic the structure and function of helical peptides (Chongsiriwatana et al., 2008). They are very biostable, relatively easy to make, and most importantly proteases don’t destroy these molecules. Thus Professor Gorske has chosen to make specific peptoids that perhaps could target these signaling proteins in his lab.

Fig 2: Comparison of the general molecular structure of a naturally-derived peptide versus an artificially-produced peptoid.

However, an issue that arose with creating these peptoids is that the peptoids often folded to form polyproline type 1 helices (PPI) rather than PPII helices. This is due to the differences in orientation of the connected amides (subunits of the peptoids). This leads to peptoids with PP1 helices being much more compressed than peptoids with PPII helices. While they do work as good lung surfactants and other antimicrobials, they are not suitable to target signaling proteins. 

Fig 3: Comparison of the 3D structure of polyproline 1 helix (PPI) and polyproline 2 helix (PPII), and the orientation of the respective amide subunits.

Through experimenting, Professor Gorske has found out in his lab that the best way to encourage amides to connect in the desired PPII orientation is through adding side chains on the amide subunits, and the side chains are additionally thionated – the carbon is double bonded to sulfur instead of oxygen. Currently, he is investigating whether adding more than one thionated residue can lead to the whole peptoid to adopt the desired PPII helical structure. 

This method of creating peptoids that Professor Gorske is working to devise can be implicated in so many uses within medicine. As peptoid drugs can mimic biological molecules, they can more precisely target the required proteins, to help inhibit or promote signaling pathways back to normal. Professor Gorske’s research is therefore crucial to the ongoing development of medicine and healthcare. 

References

“Biomimetics Articles from across Nature Portfolio.” Nature News, Nature Publishing Group, https://www.nature.com/subjects/biomimetics. 

Chen, Yu-An, et al. “WW Domain-Containing Proteins Yap and Taz in the Hippo Pathway as Key Regulators in Stemness Maintenance, Tissue Homeostasis, and Tumorigenesis.” Frontiers in Oncology, vol. 9, 2019, https://doi.org/10.3389/fonc.2019.00060. 

Chongsiriwatana, Nathaniel P., et al. “Peptoids That Mimic the Structure, Function, and Mechanism of Helical Antimicrobial Peptides.” Proceedings of the National Academy of Sciences, vol. 105, no. 8, 2008, pp. 2794–2799., https://doi.org/10.1073/pnas.0708254105. 

Embl-Ebi. “What Are Protein Domains?” What Are Protein Domains? | Protein Classification, https://www.ebi.ac.uk/training/online/courses/protein-classification-intro-ebi-resources/protein-classification/what-are-protein-domains/. 

“Hippo Signaling.” Cell Signaling Technology, 2010, https://www.cellsignal.com/pathways/hippo-signaling-pathway.

 

Filed Under: Chemistry and Biochemistry, Science

The Possibilities of the CRISPR-Cas9 System

April 2, 2023 by Stephanie Christianson '26

          As humans continue to further explore the fields of science, they deepen their understanding of convoluted subjects through the use of advanced technologies. One of the notable technologies today is the CRISPR-Cas9 system, a highly precise DNA editing tool that allows for genome manipulation in humans, animals, and plants. CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) works with a CRISPR-associated (Cas) nuclease, which was originally derived from a genome editing system used as immune defense by bacteria. To put it simply, if infected by a virus, the bacteria captures a small piece of the invading viruses’ DNA and inserts their own DNA to create a CRISPR segment (Tavakoli et al., 2021). With this segment, the bacteria can produce RNA segments that will attach to parts of the viruses’ DNA if it attacks again. The bacteria use the Cas9 enzyme to cut the viruses’ DNA apart and incapacitate it. 

          Scientists adapted the system so it could be inputted into the human genome and edit DNA. Researchers created small segments of RNA that have a “guide” sequence which binds to a target sequence in the DNA and attaches to the Cas9 enzyme (Tavakoli et al., 2021). The guide RNA (gRNA) identifies the intended DNA sequence and the Cas9 enzyme cuts the specific location, similar to how the process occurs in bacteria. The cell’s own DNA machinery is then used to add or delete pieces of the genetic material, known as gene knock-in and gene knockout, respectively. However, it can also alter the DNA by replacing segments with more customized sequences. CRISPR activation (CRISPRa) is used to up-regulate the expression of a gene while CRISPR interference (CRISPRi) down-regulates the expression of a cell (CRISPR Guide).

Figure 1. Gene Knockout
Figure 2. Activation of Target  Gene with CRISPRa

                                       Note. Adapted from CRISPR Guide, Addgene, 2022.

          There are many potential applications in cancer immunotherapy, treatment of genetic diseases, improving plant genetic variation, and more. For example, there have been advances towards mitigating the effects of blood disorders such as sickle cell disease (SCD). In those with SCD, the misshapen red blood cells can block blood vessels, thus slowing or stopping blood flow. Effects of this fatal disease are anemia, chronic pain, strokes, and organ damage. In this instance, CRISPR technology is not used to directly rectify the disease-inducing gene variant. Instead of restoring adult hemoglobin, it works to increase the levels of fetal hemoglobin, an oxygen carrier protein that only fetuses make in the womb (Henderson, 2022). Since it’s not affected by the sickle cell mutation, it can be a substitute for the defective adult hemoglobin in red blood cells (Henderson, 2022).

Figure 3. Hemoglobin Switching in Infants

Note. Adapted from CRISPR Clinical Trials: A 2022 Update, Henderson, 2022, Copyright 2022 by Innovative Genomics Institute.

         As seen in the diagram above, SCD symptoms begin during infancy when levels of fetal hemoglobin decrease. The blood stem cells are harvested from the blood and then the genomes are edited to activate the fetal hemoglobin gene. Next, chemotherapy eliminates the disease-inducing blood stem cells from the person’s body, and the genome-edited stem cells are put back into the bloodstream through an IV, creating a new blood stem cell population that produces fetal hemoglobin (Henderson, 2022). This technique is ex vivo genome editing, where the editing occurs outside the body to prevent the risk of lingering and unwanted CRISPR components in the body. Those treated for SCD in CRISPR clinical trials show normal to near-normal hemoglobin levels with at least 30% as fetal hemoglobin (Henderson, 2022).

          It raises the following questions: is it possible to select certain features in humans that are seen as favorable or desirable? Is it possible to have almost complete manipulation of physical features or to enhance the body’s biological processes to unlock superhuman abilities only seen in movies? These human experimentations would be best measured if implemented during the early stages of life so as to let the body integrate the changes and develop properly. Perhaps we could alter ourselves to increase muscle mass, heighten athletic ability, or augment intelligence. In regard to altering the human genome, there are certain limitations as to what can and can’t be done without violating certain ethical boundaries. 

          This can be seen in the case of He Jianku, a Chinese scientist who used CRISPR to edit two embryos, both of which are now living babies. Though there was little information that only came from He himself and the Chinese government, it has been said that sometime in late 2017, He injected the two embryos with a CRISPR construct that would delete a 32-base-pair in the CCR5 gene on chromosome 3, leading to a non-functional CCR5 protein (Greely, 2019). He sought to achieve humans who could not contract AIDS because they don’t have this functioning protein (Greely, 2019). Though this theory was later proved wrong and the CRISPR construct did not fulfill his intentions, he managed to induce never before seen changes that led to the production of non-functional proteins. His actions prompted the Chinese court to convict him on the basis of deliberately violating medical regulations (Greely, 2019). Could it be argued that pushing the boundaries are necessary for scientific growth and greater human evolution? How far is too far? As CRISPR and other gene editing tools continue to develop, we can keep imagining the unnerving yet exciting possibilities that are awaiting.

 

Literature Cited

CRISPR Guide. (n.d.). Addgene. 

Greely, H. T. (2019). CRISPR’d babies: human germline genome editing in the ‘He Jiankui affair’. Journal of Law and Biosciences, 6(1), 111-183.

Henderson, H. (2022). CRISPR Clinical Trials: A 2022 Update. Innovative Genomics Institute.

Tavakoli, K., Pour-Aboughadareh, A., Kianersi, F., Poczai, P., Etminan, A., & Shooshtari, L. (2021). Applications of CRISPR-Cas9 as an Advanced Genome Editing System in Life Sciences. BioTech, 10(3), 14. 

What are genome editing and CRISPR-Cas9? (2022). MedlinePlus.

Filed Under: Biology, Science

The Chronic Lyme Debate

April 2, 2023 by Sophie Nigrovic '24

Second possibly only to mosquitos, ticks are the most reviled insect found in New England nature. Like mosquitos, which are notorious vehicles for viruses such as Zika and West Nile, blacklegged ticks (deer ticks) spread Borrelia burgdorferi infection, resulting in Lyme disease. Affecting over 30,000 people a year in the United States, mostly in the northeastern states, Lyme disease is a bacterial infection which causes both local and global symptoms. Early symptoms include fever, muscle fatigue, swollen lymph nodes, and, mostly notably, an erythema migrans rash. Left untreated, patients may develop facial palsy (partial facial paralysis), arthritis, central nervous system inflammation, and heart palpitations. Diagnosis of Lyme disease is based primarily on symptoms and the possibility of exposure to Lyme-carrying ticks, although laboratory tests of patient serum for anti-B. Burgdorferi antibodies may also be considered. Treatments usually consist of a several week course of antibiotics. 

Although the majority of Lyme disease patients recover after initial treatment, 5-20% of patients continue feeling symptoms such as fatigue, muscle pain, and difficulty concentrating. This disorder, called post-treatment Lyme disease syndrome, falls under a broader category of disorders referred to as “chronic Lyme disease.” Also included in this category are patients without a history of Lyme disease but with Lyme-like symptoms; patients with other recognizable disorders seeking an alternative diagnosis; and patients with positive serological results for anti-B. Burgdorferi antibodies but no past exposure to ticks or other routes of infection. 

The majority of chronic Lyme patients fall into the middle two categories: those with symptoms but no history and the misdiagnosed. Moreover, in clinical trials, traditional treatment routes for Lyme disease such as antibiotics have not been effective in alleviating symptoms. Because many of those diagnosed with chronic Lyme do not match the diagnostic criteria for traditional Lyme disease, most scientists and physicians reject the diagnosis. However, a small but very vocal group of patients and physicians fervently believe in the existence of chronic Lyme disease. They are represented by powerful advocacy groups such as the International Lyme and Associated Diseases Society (ILADS) and the Lyme Disease Association (LDA). These groups have been effective at lobbying politicians and regulators to get protections for chronic Lyme sufferers, even as the physician community become increasingly convinced of its inaccuracy.

Although Lyme disease may seem a relatively simple disease with a clear cause (tick-borne bacterial infection) and treatment plan (antibiotics), the controversy over chronic Lyme disease reveals complexities. And this particular controversy doesn’t seem to be abating. It seems that the concept of chronic Lyme disease, like the disorder it purports to describe, is here to stay.

 

Works Cited:

CDC. (2022, January 19). Lyme disease home | CDC. Centers for Disease Control and Prevention. https://www.cdc.gov/lyme/index.html 

Chronic symptoms. (2018, April 11). Lyme Disease. https://www.columbia-lyme.org/chronic-symptoms 

Feder, H. M., Johnson, B. J. B., O’Connell, S., Shapiro, E. D., Steere, A. C., & Wormser, G. P. (2007). A critical appraisal of “chronic lyme disease.” New England Journal of Medicine, 357(14), 1422–1430. https://doi.org/10.1056/NEJMra072023 

Lantos, P. M. (2011). Chronic Lyme disease: The controversies and the science. Expert Review of Anti-Infective Therapy, 9(7), 787–797. https://doi.org/10.1586/eri.11.63 

Mosquito-borne diseases | niosh | cdc. (2020, February 21). https://www.cdc.gov/niosh/topics/outdoor/mosquito-borne/default.html 

Whelan, D. (n.d.). Lyme inc. Forbes. Retrieved April 2, 2023, from https://www.forbes.com/forbes/2007/0312/096.html 

Filed Under: Biology, Science Tagged With: chronic lyme, lyme disease, ticks

The role of info chemicals in seabird plastic ingestion

April 2, 2023 by Angel Del Valle Cardenas '26

Short-tailed Shearwater (Puffinus tenuirostris), Ryan Shaw (2009)

Plastic debris is widespread in our waters with more than a quarter of a billion metric tons of plastic suspended in its global oceans. This abundant plastic pollution is being consumed by hundreds of organisms, ranging from tiny zooplankton to giant baleen whales. Seabirds are especially at risk, with a projection model concluding that over 99% of all seabird species will have ingested plastic debris by 2050. The consumption of plastic is incredibly harmful to seabirds as it reduces the storage volume of the stomach which ultimately leads to starvation and death. In the last few years, it has been discovered that the plastic problem is much more complicated than we thought before as many seabirds rely on their sense of smell to locate their prey instead of just visually. A 2016 study has brought to light this common misconception of marine organisms consuming plastic debris solely based on visual cues and has introduced a new factor: dimethyl sulfide (DMS). 

DMS is an infochemical used by foraging organisms as a way to find prey in marine environments. The production of DMS is from the enzymatic breakdown of its chemical precursor, dimethylsulfoniopropionate (DMSP), which increases when zooplanktons eat, letting other marine organisms know of the presence of a new meal. Plastic debris is an excellent substrate for biota that produce these infochemicals due to its convenience in biofouling, which is the accumulation of organisms on a surface. Since plastic debris can be easily fouled by DMS-producing organisms, then the debris can also produce a DMS signature that is significant enough to lead seabirds and similar organisms to consume it. 

To prove this, scientists examined the sulfur signature of plastic beads from the most common types of plastic found in the ocean. These plastic beads were tested for sulfur signatures after either being exposed to marine conditions or never being exposed to these conditions. The beads exposed to marine conditions were deployed off the coast of California at the Bodega Marine Laboratory and Hopkins Marine Station at oceanographic buoys and then retrieved after approximately three weeks. After examining each plastic bead, it was found that the samples not exposed to marine conditions did not produce any DMS signature. However, every sample that was tested after marine exposure was found to have produced a DMS signature. Even after less than a month of marine exposure, these plastic samples were found to produce DMS signatures that were significant enough to be detected by seabirds.

Additionally, the study was able to predict the importance of DMS and plastic ingestion patterns within seabirds through data analysis. Plastic ingestion data was analyzed from 55 studies among 25 procellariiforms––the order under which seabirds fall––to determine that DMS responsiveness has a significant positive effect on the frequency of plastic ingestion. Additionally, plastic ingestion patterns were predicted through calculations using data from previous studies to find that DMS-responsive species ingest plastic five times as frequently as non-DMS-responsive species.

The study has challenged the frequent assumption that marine organisms consume plastic because it is visibly mistaken for prey, suggesting rather that chemical cues like DMS play a role. This plastic ingestion has many implications, one such being that the semiannual movement patterns of seabirds between the Southern and Northern Hemispheres can create contact with plastic on a global scale rather than just a regional one. Although the primary focus of this study was on seabirds, they are not the only species that respond to DMS––sea turtles, penguins, and various other organisms have been shown to use DMS and DMSP as foraging compounds and could be impacted similarly. We must start mitigating the plastic waste we produce and work towards cleaning up our oceans. While this is a huge step to take, we can begin by looking for alternatives to plastic that are safer for the environment and reduce the amount of plastic that we use in our everyday lives.


References:

Savoca, M. S., Wohlfeil, M. E., Ebeler, S. E., & Nevitt, G. A. (2016). Marine plastic debris emits a keystone infochemical for olfactory foraging seabirds. Science Advances, 2(11). https://doi.org/10.1126/sciadv.1600395 

Eriksen, L. C. M. Lebreton, H. S. Carson, M. Thiel, C. J. Moore, J. C. Borerro, F. Galgani, P. G. Ryan, J. Reisser, Plastic pollution in the world’s oceans: More than 5 trillion plastic pieces weighing over 250,000 tons afloat at sea. PLOS ONE 9, e111913 (2014).

Wilcox, E. Van Sebille, B. D. Hardesty, Threat of plastic pollution to seabirds is global, pervasive, and increasing. Proc. Natl. Acad. Sci. U.S.A. 112, 11899–11904 (2015).

Ocean plastics pollution. Ocean Plastics Pollution. (n.d.). Retrieved April 2, 2023, from https://www.biologicaldiversity.org/campaigns/ocean_plastics/?adb_sid=71bc9f17-356c-492f-9204-f0e22e2752b6

Filed Under: Environmental Science and EOS, Science Tagged With: birds, marine, ocean, plastic, seabirds

  • « Go to Previous Page
  • Page 1
  • Page 2
  • Page 3
  • Page 4
  • Page 5
  • Page 6
  • Go to Next Page »

Primary Sidebar

CATEGORY CLOUD

Biology Chemistry and Biochemistry Computer Science and Tech Environmental Science and EOS Honors Projects Math and Physics Psychology and Neuroscience Science

RECENT POSTS

  • Floating Systems: Jellyfish and Evolving Nervous Systems May 22, 2025
  • Biological ChatGPT: Rewriting Life With Evo 2 May 4, 2025
  • Unsupervised Thematic Clustering for Genre Classification in Literary Texts May 4, 2025

FOLLOW US

  • Facebook
  • Twitter

Footer

TAGS

AI AI ethics Alzheimer's Disease antibiotics artificial intelligence bacteria Bathymetry Beavers Biology brain Cancer Biology Cell Biology Chemistry and Biochemistry Chlorofluorocarbons climate change Computer Science and Tech CRISPR Cytoskeleton Depression dreams epigenetics Ethics Genes honors Luis Vidali Marine Biology Marine Mammals Marine noise Medicine memory Montreal Protocol Moss neurobiology neuroscience Nutrients Ozone hole Plants Psychology and Neuroscience REM seabirds sleep student superintelligence Technology therapy

Copyright © 2025 · students.bowdoin.edu