by Jody Finch (@jody_fin)

Jody is a rising senior at Georgia State University and a CEED Summer Fellow

There has been growing interest in biological changes and influences as they pertain to mental health. You may have seen examples of this in newspapers, google search results, or even on the news. Scientists have delved into various subfields of biology such as genetics, microbiology, and physiology to determine their links to mental health problems. For example, UNC has championed this approach by examining the genetics of eating disorders through the Eating Disorder Genetics Initiative study [1].

Another area of interest has been looking at how physiology is linked to mental health. Physiology focuses on how a living thing’s cells, organs, and physical systems carry out normal functioning. This area includes how the brain may be involved in mental heath disorders. With all of this interest, it is no wonder that the question of how the brain is involved in mental health has been posed.

We have known that the brain is important for the functioning of human beings for a long time. In fact, we learned that different parts of the brain are involved in different processes through seminal case studies like that of Phineas Gage. Phineas Gage was a railroad foreman in the mid-1800s who suffered a tragic accident when a tamping iron pierced up through his jaw and out the top of his head in an explosion. This accident ended up damaging his frontal lobe which is in part responsible for emotional and impulse control, organization, and planning. After the accident, Gage was remarkably changed according to family and friends as he became easily irritable, impulsive, and rude [2].

With the knowledge that different parts of the brain are involved in diverse processes, called localization of function, scientists have been interested in measuring how different components of the brain are associated with mental health. These components of the brain are grey matter, white matter, and cerebral spinal fluid. Grey matter is mostly responsible for processing and sending information in the brain [3] and makes up the outer layer [4]. White matter acts like insulation in the brain and helps carry electrical signs more quickly from one brain cell, called a neuron, to another and is located just below the grey matter [5]. Cerebral spinal fluid surrounds the brain and is important for protecting the brain, nourishing it, and removing waste [6].

These components of the brain can be measured with magnetic resonance imaging, commonly abbreviated as MRI. You may have even had an MRI yourself! MRI uses magnets to measure and distinguish the different tissues in the brain [7]. Recent research has examined how eating disorders may be associated with changes in grey and white matter.  

Some studies have found that reductions in grey matter volume across the whole brain, but particularly the insula and frontal lobe, are associated with eating disorders broadly [8]. Some brain changes have been found to be specifically associated with different types of eating disorders. For example, reductions in grey matter in the orbitofrontal cortex and greater grey matter in the insula are associated with anorexia nervosa. These regions have been shown to be associated with higher desire for thinness, which may help explain a mechanism for anorexia nervosa [8]. Grey matter in bulimia nervosa, however, is reduced in frontal, parietal, and cingulate regions, which are associated with purging behavior [8]. Furthermore, white matter in the anterior cingulate cortex and medial frontal cortex are associated with binge-eating disorder and bulimia nervosa which are responsible for processing rewards and understanding of one’s own emotional state (Frank 2019). Importantly, these changes are normally only seen in acute stages of the illness and return to normal after recovery [8, 9].

More research is needed to better understand how and why these changes happen in acute phases of eating disorders; however, current research is on its way to providing the answers to these questions. The goal of neuroimaging and other biological research is to develop treatments for eating disorders that may eventually include medication and other biological interventions in conjunction with therapy and nutritional services.

References

1. About EDGI. EDGI. (2021, April 6). https://edgi.org/about/.
2. Smithsonian Institution. (2010, January 1). Phineas Gage: Neuroscience’s Most Famous Patient. Smithsonian.com. https://www.smithsonianmag.com/history/phineas-gage-neurosciences-most-famous-patient-11390067/.
3. Chiao CC, Lin CI, Lee MJ. Multiple Approaches for Enhancing Neural Activity to Promote Neurite Outgrowth of Retinal Explants. Methods Mol Biol. 2020;2092:65-75. 
4. Mercadante AA, Tadi P. Neuroanatomy, Gray Matter. [Updated 2020 Jul 31]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK553239/
5. Purves D, Augustine GJ, Fitzpatrick D, Hall WC, LaMantia AS, McNamara JO, White LE (2008). Neuroscience (4th ed.). Sinauer Associates. pp. 15–16. ISBN 978-0-87893-697-7.
6. Telano LN, Baker S. Physiology, Cerebral Spinal Fluid. [Updated 2021 Jul 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK519007/
7. U.S. Department of Health and Human Services. (n.d.). Magnetic Resonance Imaging (MRI). National Institute of Biomedical Imaging and Bioengineering. https://www.nibib.nih.gov/science-education/science-topics/magnetic-resonance-imaging-mri#:~:text=How%20does%20MRI%20work%3F,-MRI%20of%20a&text=MRIs%20employ%20powerful%20magnets%20which,pull%20of%20the%20magnetic%20field 
8. Frank, G. K. W. (2019). Neuroimaging and eating disorders. Current Opinion in Psychiatry, 32(6), 478-483. https://doi.org/10.1097/yco.0000000000000544
9. Frank G. K. (2015). Advances from neuroimaging studies in eating disorders. CNS Spectrums, 20(4), 391–400. https://doi.org/10.1017/S1092852915000012