Knowing Neurons
Did You Know?

The Neuroscience of Zombies: Unmasking the Zombie Mind

By Caitlin Goodpaster

As spooky season descends upon us, it’s intriguing to explore the connections between neuroscience and a Halloween classic: the zombie. While the introduction of zombism to fiction can be attributed to William Seabrook’s The Magic Island in 1929, zombies weren’t propelled into the zeitgeist until the 1960’s with Romero’s Night of the Living Dead (“Zombies”, 2019; Eldridge, 2023). Since then, zombies have become an integral part of pop culture, making their appearance in video games such as Resident Evil, shows like The Walking Dead and iZombie, as well as countless movies. Whether you’re watching on the television or running from them in your favorite haunted house, most renditions have a few telltale signs that you’re about to encounter the living dead. Interestingly, many of these characteristics are strikingly similar to symptoms of neurological dysfunction.  Which raises the question: could damage to the central nervous system explain many of characteristics of a zombie infestation? 

Interestingly, many of these characteristics are strikingly similar to symptoms of neurological dysfunction… could damage to the central nervous system explain many of characteristics of a zombie infestation?

 

While being chased by these monsters, a glimmer of hope arises from their slow and disjointed movement. Dopamine is a neurotransmitter responsible for many functions in the brain, including reward, motivation, and regulating movement of the body (Liu & Kaeser, 2019). One main source of dopamine in the brain is the substantia nigra, or “black substance,” a region named for its darker coloring compared to the rest of the brain. Damage to neurons that produce dopamine in this region can lead to disturbances in initiating movement and balance as well as stiff muscles, like the neurodegenerative condition Parkinson’s disease (Ungerstedt et al., 1970). Perhaps zombies, too, are suffering from a loss of dopamine, slowing their pursuit to a crawl. Just keep in mind that although they may not be the fastest monsters around, zombies can still inflict a lot of damage. 

Perhaps zombies, too, are suffering from a loss of dopamine, slowing their pursuit to a crawl

While a zombie’s uncoordinated movement toward you may not instill fear initially, that all changes when you realize they have one singular goal: to kill you. The aggression zombies exhibit is so irrational and volatile that brain damage could very well be the source. Specifically, damage to an area of the brain called the hypothalamus could be responsible. This area has many important roles, including maintaining homeostasis and regulating hunger, and mood. Rodent studies have determined that one particular area, the ventromedial hypothalamus, plays an important role in driving aggressive behavior. Researchers found that stimulating a subset of neurons in this area is sufficient to induce aggression in both male and female mice. Conversely, inhibiting this subset of neurons also reduces the likelihood that they will engage in attack behavior (Hashkaway et al., 2017). Thus, overactivation of the hypothalamus could lead to a zombie’s desire to attack. 

Damage to frontal regions of the brain could also lead to increased aggression. This area of your brain is important for inhibiting the instinct-driven functions of the amygdala and hypothalamus (Banks et al., 2007; Otto et al., 2014). When it is thrown out of whack, regions like the ventromedial hypothalamus and amygdala can take over and drive behavior. Some theorize that this reduced influence from frontal regions of the brain may underlie the risk-taking and heightened emotions that we often see during adolescence (Casey, 2008).  Just think of a zombie as a recently grounded angsty teen with absolutely no check on their emotional instincts. 

Just think of a zombie as a recently grounded angsty teen with absolutely no check on their emotional instincts

Another tell-tale sign of a zombie is their voracious hunger…for brains! While scientists have not come across real-life conditions involving an urge to eat brains, neuroscience research can help us identify which brain region may cause a zombie’s insatiable drive to consume them. Given how important the hypothalamus is to maintaining balance in the body, it is no surprise that this area also is a likely culprit behind insatiable hunger. The lateral hypothalamus is important in hunger control and feeding behavior (Stuber & Wise, 2016). Specifically, when you stimulate inhibitory neurons in this region at low frequencies it leads to increases in food intake in mice, even though they were not food deprived (Barbano et al., 2016). One human genetic disorder, Prader-Willi Syndrome, leads to alterations in this part of the brain. This rare genetic disorder results in a number of physical, intellectual, and behavioral symptoms, one of which is hyperphagia, or overeating due to the inability to feel full (Driscoll et al., 1998). This further highlights the relationship between the lateral hypothalamus and hunger-related behaviors. The unmistakable hyperphagia of a zombie is apparent in their ceaseless quest for brains, suggesting the possibility that an impaired hypothalamus could be driving this behavior. 

The unmistakable hyperphagia of a zombie is apparent in their ceaseless quest for brains, suggesting the possibility that an impaired hypothalamus could be driving this behavior

While we may never actually know what causes zombies to become the monsters they are, it is interesting to probe whether or not a zombie apocalypse is more feasible than you may think. To delve deeper into the neurobiology underlying the undead, check out Timothy Verstynen and Bradley Boytek’s book Do Zombies Dream of Undead Sheep? A Neuroscientific View of the Zombie Brain. Who knows, maybe it could give you the upper hand in an upcoming zombie apocalypse.

~~~

Written by Caitlin Goodpaster
Illustrated by Vidya Saravanapandian
Edited by Zoë Dobler, Allison Lindquist, and Rebeka Popovic

~~~

Become a Patron!

a woman in a lab coat looking at an image of the brain on a computer
References

Banks SJ, Eddy KT, Angstadt M, Nathan PJ, Phan KL. (2007). Amygdala-frontal connectivity during emotion regulation. Soc Cogn Affect Neurosci., 2(4):303-12. Doi: 10.1093/scan/nsm029. 

Barbano MF, Wang H, Morales M, Wise RA. (2016). Feeding and Reward Are Differentially Induced by Activating GABAergic Lateral Hypothalamic Projections to VTA. Journal of Neuroscience, 36 (10) 2975-2985. Doi: 10.1523/JNEUROSCI.3799-15.2016.

Casey B, Getz S, Galvan A. (2008). The adolescent brain. Developmental Review, 28, 62-77. doi: 10.1016/j.dr.2007.08.003

Driscoll DJ, Miller JL, Cassidy SB. (1998). Prader-Willi Syndrome. In: Adam MP, Mirzaa GM, Pagon RA, et al., editors. GeneReviews. https://www.ncbi.nlm.nih.gov/books/NBK1330/#.

Eldridge A. (2023) zombies. In Encyclopaedia Britannica. https://www.britannica.com/topic/zombie-fictional-creature

Hashikawa K, Hashikawa Y, Tremblay R. Zhang, J, Feng, JE, Sabol A, Piper WT, Lee H, Rudy B, Lin D. (2017). Esr1+ cells in the ventromedial hypothalamus control female aggression. Nat Neurosci 20, 1580–1590. Doi: 10.1038/nn.4644.

Liu C, Kaeser PS. (2019). Mechanisms and regulation of dopamine release. Curr Opin Neurobiol, 57:46-53. Doi: 10.1016/j.conb.2019.01.001.

Otto B, Misra S, Prasad, A, McRae K. (2014). Functional overlap of top-down emotion regulation and generation: An fMRI study identifying common neural substrates between cognitive reappraisal and cognitively generated emotions. Cogn Affect Behav Neurosci 14, 923–938. Doi:10.3758/s13415-013-0240-0https://link.springer.com/article/10.3758/s13415-013-0240-0.

Stuber GD, Wise RA. (2016). Lateral hypothalamic circuits for feeding and reward. Nat Neurosci., 19(2):198-205. Doi: https://pubmed.ncbi.nlm.nih.gov/26814589/10.1038/nn.4220. 

Ungerstedt U, Arbuthnott GW. (1970). Quantitative recording of rotational behavior in rats after 6-hydroxydopamine lesions of the nigrostriatal dopamine system. Brain Res., 24:485–493. Doi: 10.1016/0006-8993(70)90187-3

Zombies. (2019, June 10). History.com. https://www.history.com/topics/folklore/history-of-zombies.

Author

  • Caitlin Goodpaster

    Caitlin earned her Bachelor’s degree at The Ohio State University before joining the Neuroscience Interdepartmental PhD Program at the University of California, Los Angeles. In the lab of Dr. Laura DeNardo, she studies how early life stress impacts prefrontal circuitry throughout development and contributes to alternations in avoidance behaviors. She is passionate about understanding how early experiences can lead to the development of atypical behaviors and is motivated to eliminate to stigma surrounding mental illness.

Caitlin Goodpaster

Caitlin earned her Bachelor’s degree at The Ohio State University before joining the Neuroscience Interdepartmental PhD Program at the University of California, Los Angeles. In the lab of Dr. Laura DeNardo, she studies how early life stress impacts prefrontal circuitry throughout development and contributes to alternations in avoidance behaviors. She is passionate about understanding how early experiences can lead to the development of atypical behaviors and is motivated to eliminate to stigma surrounding mental illness.