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For 25 years, the Vanderbilt Brain Institute has striven to understand the intricacies of evolutionary neuroscience, especially the human brain.

Reed Hightower | September 29th, 2024

Most scientists agree life emerged on Earth around 3.8 billion years ago. The first cell — dubbed the “protocell” — would evolve into every living cell on the planet. Between 3.8 billion years ago and now, different factions of cells — which we named “organisms” — have been competing for essential elements of life, such as food and oxygen. In a largely unpopular decision, the vertebrate faction developed brains, so that they could better decide what actions to take in fight-or-flight situations. These brains would later evolve to orchestrate behaviors that we have figured out, such as motion and sensation, as well as more abstract phenomena like perception of time and self-awareness.

Fast forward to the end of the 20th century, and Vanderbilt had become so full of faculty studying the brain that they needed to establish an overseeing body to organize these efforts. Thus, the Vanderbilt Brain Institute was established by driven faculty members in 1999. Its primary purpose was to facilitate communication and collaboration between Vanderbilt’s leaders in neuroscience. It quickly drew the attention of new faculty, and it appeared the focus on evolutionary neuroscience was not going away.

Who was paving the way?

Distinguished Centennial Professor of Psychology Dr. Jon Kaas began his work at Vanderbilt in 1973. Dr. Kaas is credited with several key discoveries in the field of neuroscience, including distinguishing a secondary somatosensory cortex (S2) neighboring the primary somatosensory cortex (S1), identifying the medial temporal and dorsomedial areas in vision (V5 and V6), and describing changes in somatosensory cortices that led to our understanding of cortical plasticity. Dr. Kaas’ research further compares these sensory features among primates and other animals to look at the change in sensory systems throughout history. 

Dr. Vivien Casagrande, another pioneering professor who brought multi-electrode recording and in vivo brain imaging for research to Vanderbilt, discovered a visual pathway unique to primates and studied changes in the visual system across species.

Dr. Kenneth Catania, who came to Vanderbilt in 1997, studies uniquely specialized species and how their behaviors and physiology evolved. Dr. Catania has published on a range of topics, including the escalation between toxic newts and poison-resistant snakes, the evolution of electricity-sensitive fish into electric eels, and the neurotransmitter-embedded stings of the emerald cockroach wasp. Additionally, he studies the changes in behavior patterns and the way cognitive information is laid out in the brain between species. For this work, he was named a Guggenheim Fellow as well as a MacArthur Fellow and was awarded a “genius grant” in 2006.

What’s new in evolutionary neuroscience at Vanderbilt?

In 2016, Dr. Suzana Herculano-Houzel joined the Vanderbilt faculty with the goal of studying comparative neuroanatomy. In her work, Dr. Herculano-Houzel looks at the relationship between the sizes and shapes of brains as well as their internal architecture. In her work, Dr. Herculano-Houzel has shown that primate brains have more neurons relative to the mass of their brains than any other family of animals. Additionally, she has shown that human brains fall along the same trend of neurons per gram as non-human primates, implying that the gap between us and primates has to do with the arrangement of neurons in our brains, not the number.

A more recent addition to the Vanderbilt Brain Institute, Dr. Christos Constantinidis researches how areas of the brain change both in development and across primates and other mammals. One fascinating investigation led by Dr. Constantinidis is looking at changes in the default mode network (DMN), a set of neural structures that is activated at rest and during thoughts of self-awareness. Many believe the DMN could be the center of consciousness. Dr. Constantinidis has shown that connections within the DMN are stronger within human brains than other non-human primate brains, implying that our brains are designed for self-awareness more than our closest primate relatives. His lab has also been able to create a cognitive evolution “map” displaying these changes in the DMN along different primate species.

Much like the evolution of the protocell into complex organisms, it is unclear how so many evolutionary neuroscientists came to work at Vanderbilt. It may have started with the strong research core at Vanderbilt, supported by a faculty that won Nobel Prizes in Physiology and Medicine in 1971, 1972, and 1986, and branched out to evolution. Ultimately, evolutionary neuroscientists may have found their call to Vanderbilt in the university’s incentive towards collaboration. Just as Vanderbilt brings together scientific minds to better their work, researchers have brought together the distant brains of the animal kingdom. 

But there are still many questions to answer: how is consciousness made? How did the first neurons decide to start manipulating electricity? Did our brains have to be designed this way? And why do afternoon naps leave me either in bliss or unaware of who I am and how I got here? Only by comparing the processes, designs, and connections between many different brains can we uncover the past of our species, and the purposes of our minds, and this research is being done on Vanderbilt’s collaborative, open campus. 

References

Schrum, Jason P., et al. “The Origins of Cellular Life.” Cold Spring Harbor Perspectives in Biology, vol. 2, no. 9, Sept. 2010, p. a002212. PubMed Central, https://doi.org/10.1101/cshperspect.a002212.

“Turning Heads: The Vanderbilt Brain Institute Has Emerged as a Hub of Discovery as Neuroscience’s Influence Expands.” Vanderbilt University, https://news.vanderbilt.edu/2020/08/05/turning-heads-the-vanderbilt-brain-institute-has-emerged-as-a-hub-of-discovery-as-neurosciences-influence-expands/. Accessed 8 Apr. 2024.

“Vanderbilt Neuroscientist Ken Catania Receives MacArthur ‘Genius Grant.’” Vanderbilt University, https://news.vanderbilt.edu/2006/09/18/vanderbilt-neuroscientist-ken-catania-receives-macarthur-genius-grant-58899/. Accessed 16 Apr. 2024.

Garin, Clément M., et al. “An Evolutionary Gap in Primate Default Mode Network Organization.” Cell Reports, vol. 39, no. 2, Apr. 2022, p. 110669. PubMed, https://doi.org/10.1016/j.celrep.2022.110669.

Jabr, Ferris. “How Humans Evolved Supersize Brains.” Quanta Magazine, 10 Nov. 2015, https://www.quantamagazine.org/how-humans-evolved-supersize-brains-20151110/.

Garin, Clément M., et al. “Multilevel Atlas Comparisons Reveal Divergent Evolution of the Primate Brain.” Proceedings of the National Academy of Sciences of the United States of America, vol. 119, no. 25, June 2022, p. e2202491119. PubMed, https://doi.org/10.1073/pnas.2202491119.

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