Motivation and emotion/Book/2024/Gut-brain axis and emotion
What is the gut-brain axis and how does it influence emotion?
Ensure exact match of wording and casing (capitalisation) with the 2024 list of topics.
All sub-titles end with a question mark.
Seek approval for any changes to wording and punctuation.
Do not list author name. Authorship is as per the page's edit history.
Overview
editOverview: one to four paragraphs inbetween the scenario and focus questions. Suggested 180 to 330 words.
- The gut acts as our second brain, directing the digestion of food through the body and absorption of nutrients. (Figure 1)
- Does the communication between the gut and the brain influence emotions?
- Mental health challenges related to the gut-brain axis.
- Optimising positive emotion and mood through the gut-brain axis.
- Integral to understand how the gut influences emotion to avoid dysregulation of emotion.
Suggestions for this section:
* Engage the reader with a scenario, example, or case study, and an accompanying image
* Explain the problem and why it is important
* Outline how psychological science can help
* Present focus questions
Focus questions:
|
Understanding the gut-brain axis
editTo understand how to gut-brain axis influences our emotions, we first have to understand how it works, as well as how the gut can communicate with the brain and vice versa.
Key components and mechanisms of communication
edit- Autonomic nervous system: The ANS consists of parasympathetic, sympathetic, and enteric (ENS) nervous systems. The ENS is embedded in the gut wall, so is the starting point for information from the gut to go to the brain. The parasympathetic and symapthetic nervous systems send information to the gut, telling it when to digest, or when to slow down and conserve energy.
- Vagus nerve: Think of the vagus nerve like the main highway between the gut and the brain. This is were most messages go back and forth. The ENS sends information to the vagus nerve, which goes up the spinal cord and to the brain.
- Hypothalamic pituitary adrenal axis (HPA Axis) releases cortisol which is sent to the gut to slow digestion (Appleton, 2018).
- Central nervous system (CNS): the brain sends messages to the gut through the CNS (Martin et al., 2018).
- However, there are many more components in this complex system such as hormonal, immune, and metabolic pathways
The microbiome
editBut what factors influence the messages the gut sends to the brain? The microbiome is an ecosystem of bacteria that is collected in the gut across the lifespan. These bacteria (microbes) help us digest food and assist in the development of our immune system, and a more diverse microbiome is associated with better physiological and emotional outcomes for the individual.
Similar to the bi-directional communication between the brain and gut, there is also a bi-directional communication between the microbiome and the gut-brain axis (Carabotti et al., 2015). Microbes produce many of the neurotransmitters sent to the brain, such as dopamine, norepinephrine, serotonin, and GABA. Animal studies have shown that microbiome interventions can also alter the levels of such neurotransmitters in the brain (Strandwitz, 2018). Recent research has found the microbiome to be increasingly influential in the gut-brain communication system, with some now referring to the system as the microbiome-gut-brain axis. Have a further look here about how the microbiome can influence emotions.
Gut-brain axis, neurotransmitters, hormones, and emotions
editIn this bidirectional communication system, it is well known the gut can respond to neurotransmitters and hormones produced and sent by the brain. Surprisingly to many, the microbiome can also produce it's own neurotransmitters to send to the brain. In fact, more than 90% of the body's serotonin is synthesised in the digestive tract, and over 50% of dopamine is produced in the gut (Liu et al., 2020).
- Lee. et, al, (2020) found stress and anxiety were significantly associated with reduced microbiome diversity, while favourable social environments as well as the trait of openness were associated with increased microbiome diversity. Overall, they found increased microbiome diversity is positively associated with emotional well-being.
- Ke. et, al, (2023) Found linkages of emotions and emotion regulation processes to the gut microbiome in a sample of women.
- The gut can also influence emotion through hormone secretion. A diverse gut microbiome regulates the secretion of leptin, grehlin, and insulin by the gut cells.
- Provide at least three bullet-points per headingʔ and sub-heading, including for the Overview and Conclusion
- Include key citations
- Use figures to illustrate concepts, add interest, and to serve as examples
- Figures can show photos, diagrams, graphs, video, audio, etcetera
- Embed figures throughout the chapter, including the Overview section
- Figures should be captioned (using Figure #. and a caption). Use captions to explain the relevance of the image to the text/
- Wikimedia Commons provides a library of embeddable images
- Images can also be uploaded to Wikimedia Commons if they are openly licensed
- Refer to each figure at least once in the main text (e.g., see Figure 2)
Dysregulation of the gut-brain axis.
edit- Microbiome dysbiosis as a disruption in the normal functioning of the microbiome resulting in dysfunction in the normal functioning of the gut-brain axis.
- Lower serotonin, which can be a result of microbiome dysbiosis, seen in those with major depressive disorder (MDD).
- Anxiety- depressive behaviours associated with microbiome dysbiosis (Carabotti et al., 2015).
- Association found between gut microbiome dysbiosis and autism spectrum disorder (ASD), with most patients with ASD suffering from some sort of gastro intestinal disorder (Taniya et al., 2022).
Interactive learning features help to bring online book chapters to life and can be embedded throughout the chapter.
- Scenarios
- Scenarios or case studies describe applied/real-world examples of concepts in action
- Case studies can be real or fictional
- A case study could be split into multiple boxes throughout a chapter (e.g., to illustrate different theories or stages)
- It is often helpful to present case studies using feature boxes.
- Feature boxes
- Important content can be highlighted in a feature box. But don't overuse feature boxes, otherwise they lose their effect.
- Consider using feature boxes for:
- Scenarios, case studies, or examples
- Focus questions
- Tips
- Quiz questions
- Take-home messages
- Links
- When key words are introduced, use interwiki links to:
- Wikipedia (e.g., Sigmund Freud wrote about (e.g., dreams) or
- Related book chapters (e.g., writer's block)
- Tables
- Use to organise and summarise information
- As with figures, tables should be captioned
- Refer to each table at least once in the main text (e.g., see Table 1)
- Example 3 x 3 tables which could be adapted
Table 1. Descriptive Caption Which Explains The Table and its Relevant to the Text - Johari Window Model
Known to self | Not known to self | |
---|---|---|
Known to others | Open area | Blind spot |
Not known to others | Hidden area | Unknown |
- Quizzes
- Using one or two review questions per major section is usually better than a long quiz at the end
- Quiz conceptual understanding, rather than trivia
- Don't make quizzes too hard
- Different types of quiz questions are possible; see Quiz
Example simple quiz questions. Choose your answers and click "Submit":
Modulating the gut-brain axis
edit- Biodiversity of the microbiome
- Psychobiotics/ Psychomicrobiotics/ Probiotics proven effective as non-toxic psychiatric interventions for depressive symptoms (Appleton, 2018).
- Vagus nerve stimulation: Johnson & Steenbergen (2022) found stimulation of the vagus nerve reduced emotional reactivity in participants. It has also been used to treat some cases of severe depression.
- Diet reconstruction as an accessible solution.
Conclusion
edit- Bidirectional Influence: The gut-brain axis involves complex, bidirectional communication. Both systems influence eachother through neural, chemical, immune, and hormonal pathways. This interaction plays a crucial role in regulating and influencing emotions.
- Microbiota's Role: Gut microbiota significantly impacts the gut-brain axis by modulating neurotransmitter production. Dysbiosis in the gut microbiome has been linked to emotional dysfunction causing anxiety, depression, and autism.
- Therapeutic Potential: Understanding and manipulating the gut-brain axis through diet, pro/pre/psychobiotics, and other interventions may be promising avenues for improving mental health and emotional well-being, highlighting the need for further research and clinical applications in this emerging field.
Take home message: By taking care of your gut—through a whole food diet, probiotics, prebiotics and stress management—you can positively impact your emotions and overall well-being.
- Suggested word count: 150 to 330 words
- It should be possible for someone to only read the Overview and the Conclusion and still get a pretty good idea of the problem and what is known based on psychological science
Suggestions for this section:
|
See also
edit- Digestive system and emotion (Book chapter, 2015)
- Emotion (Wikipedia)
- Gut-brain axis (Wikipedia)
- Junk food and psychological distress (Book chapter, 2019)
References
editCarabotti, M., Scirocco, A., Maselli, M. A., & Severi, C. (2015). The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Ann Gastroenterol, 28(2), 203-209.
Johnson, K. V. A., & Steenbergen, L. (2022). Gut Feelings: Vagal Stimulation Reduces Emotional Biases. Neuroscience, 494, 119-131. https://doi.org/https://doi.org/10.1016/j.neuroscience.2022.04.026
Ke, S., Guimond, A. J., Tworoger, S. S., Huang, T., Chan, A. T., Liu, Y. Y., & Kubzansky, L. D. (2023). Gut feelings: associations of emotions and emotion regulation with the gut microbiome in women. Psychol Med, 53(15), 7151-7160. https://doi.org/10.1017/s0033291723000612
Lee, S.-H., Yoon, S.-H., Jung, Y., Kim, N., Min, U., Chun, J., & Choi, I. (2020). Emotional well-being and gut microbiome profiles by enterotype. Scientific Reports, 10(1), 20736. https://doi.org/10.1038/s41598-020-77673-z
Liu, T., Feenstra, K. A., Heringa, J., & Huang, Z. (2020). Influence of gut microbiota on mental health via neurotransmitters: A review. Journal of Artificial Intelligence for Medical Sciences, 1(1-2), 1-14. https://doi.org/10.2991/jaims.d.200420.001
Martin, C. R., Osadchiy, V., Kalani, A., & Mayer, E. A. (2018). The Brain-Gut-Microbiome Axis. Cell Mol Gastroenterol Hepatol, 6(2), 133-148. https://doi.org/10.1016/j.jcmgh.2018.04.003
Strandwitz, P. (2018). Neurotransmitter modulation by the gut microbiota. Brain Res, 1693(Pt B), 128-133. https://doi.org/10.1016/j.brainres.2018.03.015
Taniya, M. A., Chung, H. J., Al Mamun, A., Alam, S., Aziz, M. A., Emon, N. U., Islam, M. M., Hong, S. S., Podder, B. R., Ara Mimi, A., Aktar Suchi, S., & Xiao, J. (2022). Role of Gut Microbiome in Autism Spectrum Disorder and Its Therapeutic Regulation. Front Cell Infect Microbiol, 12, 915701. https://doi.org/10.3389/fcimb.2022.915701
Suggestions for this section:
|
External links
edit- More than a gut feeling: how your microbiome affects your mood (Stanford Lifestyle Medicine)
- Do gut microbes control your personality? (Ted)
Suggestions for this section:
|