Annotated Bibliography:

1) Bravo, Javier A., et al. "Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve." Proceedings of the National Academy of Sciences 108.38 (2011): 16050-16055.

Summary of Primary Article:

Bravo and colleagues sought to answer the question of how lactic acid bacteria affect neurotransmitter receptors in the normal CNS. They illustrate the bidirectional communication of the gut-brain axis and potential therapeutic opportunities for stress induced mental illnesses such as anxiety. They injected L. rhamnosus (JB-1) in mice models to look at the changes in GABA subunit expression and anxiety related behavior from comparing germ-free mice to specific pathogen free mice. They then performed a vagotomy, surgically removed all vagal fibers in the mice, and examined behavioral changes in an open field and forced swim test. They looked at motor activty to show locomotion differences do not play a role in the measured behavioral alterations after the ingestion of JB-1 and the vagotomy. They used stress-induced hyperthermia (SIH) and elevated plus maze (EPM) tests to assess how alterations in GABA neurotransmission underpin functional and behavioral downstream effects. Figure 2 shows the GABA levels from mice fed with L. rhamnosus in different regions of the brain compared to broth fed mice.

Annotation:

This primary research article was written by scientists at College Cork, Ireland and McMaster University. Bravo has published multiple articles on the gut-brain axis, specifically gut permeability, neuropharmacology, and neurogenesis. John F. Cryan is a professor of Anatomy and Neuroscience in Ireland and has published many papers on the microbiome and gut-brain-connection.This article was edited by Professor of Microbiology and Genetics at North Carolina State University, and is part of the Proceedings of the National Academy of Sciences. I used Figure 4 from this study to provide evidence for the role of the vagus nerve in modulating anxiety and depressive-like behaviors in mouse models.

2) Heijtz, Rochellys Diaz, et al. "Normal gut microbiota modulates brain development and behavior." Proceedings of the National Academy of Sciences 108.7 (2011): 3047-3052.

Annotation:

This primary research article was written by scientists with specialites of neuroscience and genome research. They are affiliated with the Stockholm Brain Institute and the Genome Institute of Singapore. This article was edited by Arturo Zychlinsky, of Max Planck Institute for Infection Biology in Berlin. This article was intended for other microbiologists and neuroscientsits studying signaling neuronal circuits in connection to microbial exposure. They don't introduce the experimental design of a vagotmy or germ-free mice, as assume the readers understand this technique. This article was cited in the reviews of Foster (2013), Needham (2020), Cryan (2012), Sharon (2016), Cryan (2019), Foster (2015), and others. I anlayzed Figure 4 from this article to provide evidence for the altered expression of anxiety related genes in germ- free mice.

3) Cryan, John F., and Timothy G. Dinan. "Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour." Nature reviews neuroscience 13.10 (2012): 701-712.

Annotation:

Dr. Cryan is a professor of Anatomy and Neuroscience and Principal Investigator at the National University in Ireland. Dr. Cryan has written numerous articles on the gut-brain communication, sepcifically the vagus nerve. Their intended audiance is a reader without much background on the gut microbiota, as they provide a detailed overview of the microbiome, interactions with stress, and downstream effects. This review provides an overview and introduces the approach to using germ Free animals in assessing the gut microbiota. They show an overview for the pathways and mechanisms for how the microbiota influence the CNS. (Box. 1) They summarize the work looking at the vagus nerve. Figure 2 was helpful in understanding the strategies used to study the role of the microbiota-gut-brain axis: germ free, infection, faecal transplant, antibiotic, and probiotic studies. I modified Figure 1 of their article in showing bidirectional pathways of communication between the gut and the brain. Without this article, I wouldn't have understood the mechanisms of the gut-brain-axis or the strategies used to investigate such mechanisms.

4) Foster, Jane A., and Karen-Anne McVey Neufeld. "Gut–brain axis: how the microbiome influences anxiety and depression." Trends in neurosciences 36.5 (2013): 305-312.

Annotation:

Dr. Foster and Dr. Neufeld are Professors at the Department of Psychiatry and Behavioral Neurosciences at McMaster University. They both published an article that found the presense of absense of commensal microbiota influences behavior and neuroschemical alterations in the brain. [11] This review is intended for an audience with an incomplete understanding of intestinal bacteria, the microbiome, and the gut-brain-axis. They introduce the reader with a broad overview of the microbiome, then recent findings in understanding how the microbiota play a role in CNS. I utlized their Figure 1 and modified their Figure 3 in my poster. It was from the glossary in this article, where I was inspired to create a glossary page on my protfolio as I found it helpful in navigating the many microbiome/neuroscience terms.

References:

5) “Any Anxiety Disorder.” National Institute of Mental Health, U.S. Department of Health and Human Services, www.nimh.nih.gov/health/statistics/any-anxiety-disorder.shtml.

6) Behavioral and Functional Neuroscience Laboratory. Open Field. Retrieved November 20, 2020, from https://med.stanford.edu/sbfnl/services/bm/sm/openfield.html

7) Bonaz, Bruno, Thomas Bazin, and Sonia Pellissier. "The vagus nerve at the interface of the microbiota-gut-brain axis." Frontiers in neuroscience 12 (2018): 49.

8) Bull, Matthew J., and Nigel T. Plummer. "Part 1: The human gut microbiome in health and disease." Integrative Medicine: A Clinician's Journal 13.6 (2014): 17.

9) Dalile, Boushra, et al. "The role of short-chain fatty acids in microbiota–gut–brain communication." Nature Reviews Gastroenterology & Hepatology (2019): 1.

10) Dezfuli, Ghazaul, et al. "Subdiaphragmatic vagotomy with pyloroplasty ameliorates the obesity caused by genetic deletion of the melanocortin 4 receptor in the mouse." Frontiers in neuroscience 12 (2018): 104.

11) Foster, Jane A. "Microbes and the Mind."

12) Fülling, Christine, Timothy G. Dinan, and John F. Cryan. "Gut microbe to brain signaling: what happens in vagus…." Neuron101.6 (2019): 998-1002.

13) Gill, Steven R., et al. "Metagenomic analysis of the human distal gut microbiome." science 312.5778 (2006): 1355-1359.

14) Hsiao, Elaine. “Mind-Altering Microbes: How the Microbiome Affects Brain and Behavior: Elaine Hsiao at TEDxCaltech.” YouTube, TEDxTalks, 8 Feb. 2013, www.youtube.com/watch?v=FWT_BLVOASI.

15) Needham, Brittany D., Rima Kaddurah-Daouk, and Sarkis K. Mazmanian. "Gut microbial molecules in behavioural and neurodegenerative conditions." Nature Reviews Neuroscience(2020): 1-15.

16) Neufeld, K. M., et al. "Reduced anxiety‐like behavior and central neurochemical change in germ‐free mice." Neurogastroenterology & Motility 23.3 (2011): 255-e119.

17) Nickel, Thomas, et al. "Clinical and neurobiological effects of tianeptine and paroxetine in major depression." Journal of Clinical Psychopharmacology 23.2 (2003): 155-168.

18) Open Field Test. (n.d.). Retrieved November 19, 2020, from https://www.sciencedirect.com/topics/immunology-and-microbiology/open-field-test

19) Petrosino, Joseph F. "The microbiome in precision medicine: the way forward." Genome medicine 10.1 (2018): 12.

20) Powell, Nick, Marjorie M. Walker, and Nicholas J. Talley. "The mucosal immune system: master regulator of bidirectional gut–brain communications." Nature reviews Gastroenterology & hepatology 14.3 (2017): 143.

21) Qin, Junjie, et al. "A human gut microbial gene catalogue established by metagenomic sequencing." nature 464.7285 (2010): 59-65.

22) Sgritta, Martina, et al. "Mechanisms underlying microbial-mediated changes in social behavior in mouse models of autism spectrum disorder." Neuron 101.2 (2019): 246-259.

23) Slattery, David A., and John F. Cryan. "Using the rat forced swim test to assess antidepressant-like activity in rodents." Nature protocols 7.6 (2012): 1009-1014.

24) Tovote, Philip, Jonathan Paul Fadok, and Andreas Lüthi. "Neuronal circuits for fear and anxiety." Nature Reviews Neuroscience 16.6 (2015): 317-331.

Image Credits:

• Brain graphic. Digital Image. iLexx.“Illustration of the thought process of the brain.” Depositphotos. 90339092. 18 November, 2018. <https://depositphotos.com/90339092/stock-photo-brain-activity-concept.html> Accessed 9 December 2020.

• Microbiome graphic. Digital Image. Doré, Antoine. The gut microbiome. Nature. 29 January 2020. <https://www.nature.com/articles/d41586-020-00194-2> Accessed 9 December 2020

• Vagus nerve graphic. Digital Image. Vagus Nerve Stimulation by Yoga, Pranayama & Other Natural Ways. Moksha Mantra. <https://www.mokshamantra.com/vagus-nerve-stimulation-natural/> Accessed 9 December 2020.

• Nerve graphic. Digital Image. Nerve Blocks. UCSF Health. <https://www.ucsfhealth.org/treatments/nerve-blocks> Accessed 9 December 2020

• Cell graphic. Digital image. Department of Biological Sciences. Notre Dame. <https://biology.nd.edu.> Accessed 9 December 2020.

• Brain network graphic. Digital image. Zishan, Liu. Brains Cling to Old Habits When Learning New Tricks. Quanta Magazine. 27 March 2018. <https://www.quantamagazine.org/brain-computer-interfaces-show-that-neural-networks-learn-by-recycling-20180327/>Accessed 9 December 2020.