{"690967":{"#nid":"690967","#data":{"type":"news","title":"The Myth of the \u2018Lizard Brain\u2019 and the Real Trade-Off Inside Your Mind","body":[{"value":"\u003Cp\u003ESo many of life\u2019s most pivotal decisions come down to one question: Should you listen to your logic or your emotions? Popular culture often frames this tension as a struggle between two minds \u2014 a \u201cmore evolved\u201d rational layer built atop an ancient \u201clizard brain\u201d driven by primal instincts.\u003C\/p\u003E\u003Cp\u003EThis battle of the brains has also been playing out over the course of evolution, but not as a simple clash between old and new.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u201cThere was a theory proposed in the \u201850s that the brain evolved in layers starting with basic bodily functions, to emotions in the reptilian brain, leading up to sophisticated reasoning in humans,\u201d explains \u003Ca href=\u0022https:\/\/people.research.gatech.edu\/nabil-imam\u0022\u003ENabil Imam\u003C\/a\u003E, an assistant professor in the \u003Ca href=\u0022https:\/\/cse.gatech.edu\/\u0022\u003ESchool of Computational Science and Engineering\u003C\/a\u003E and a faculty member with Georgia Tech\u2019s \u003Ca href=\u0022https:\/\/neuro.gatech.edu\u0022\u003EInstitute for Neuroscience, Neurotechnology, and Society\u003C\/a\u003E (INNS). \u201cThis is not how an evolutionary biologist would think about the problem.\u201d\u003C\/p\u003E\u003Cp\u003EInstead of a \u201cnew\u201d brain layered over an \u201cancient\u201d one \u2014 or even a logical brain versus an emotional one \u2014 research published in \u003Ca href=\u0022https:\/\/www.science.org\/doi\/full\/10.1126\/sciadv.aec6112\u0022\u003E\u003Cem\u003EScience Advances\u003C\/em\u003E\u003C\/a\u003E reveals that brain evolution may come down to wiring.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EBy studying the architecture of both biological and artificial brains, Imam\u2019s team found that brain evolution is a strategic allocation of limited real estate. They propose a computational tug-of-war between two fundamentally different types of internal wiring \u2014 ones established even before birth.\u003C\/p\u003E\u003Cp\u003EThis new understanding not only helps resolve a longstanding mystery in brain evolution but could also help us design more efficient AI systems.\u003C\/p\u003E\u003Ch3\u003E\u003Cstrong\u003EThe Problem With the \u201cLizard Brain\u201d\u003C\/strong\u003E\u003C\/h3\u003E\u003Cp\u003EWhen we refer to our \u201clogical\u201d or \u201clizard\u201d brains, we\u2019re really talking about different groups of brain regions. The logical brain is known as the neocortex, the brain\u2019s outer layer responsible for vision, perception, reasoning, and other higher-level functions. For the lizard brain, the story gets a bit complicated.\u003C\/p\u003E\u003Cp\u003E\u201cThe limbic system, sometimes called the \u2018reptilian brain,\u2019 controls emotion broadly speaking \u2014 but it also has other components with distinct functions,\u201d explains Imam. The system has separate regions for memory, smell, and navigation in addition to emotional regulation. \u201cWhy do people group all these different regions into one big system? There hasn\u2019t been a good theory for what is common between these different circuits.\u201d\u003C\/p\u003E\u003Cp\u003ETo investigate, Imam\u2019s team looked beyond individual regions to examine how these systems scale across species. Instead of comparing single areas based on function, the team analyzed how the limbic system and the neocortex change together across evolutionary history.\u003C\/p\u003E\u003Cp\u003EThe result was remarkably consistent. When one component of the limbic system was larger, the others were also larger, while the neocortex was consistently smaller. These regions don\u2019t vary independently. \u201cRather,\u201d says Imam, \u201cit\u2019s a coordinated expansion of these regions across species.\u201d\u003C\/p\u003E\u003Cp\u003EThis reveals something new: The limbic system behaves not as a loose collection of functions, but as a unified network that expands and contracts as a group across evolution.\u003C\/p\u003E\u003Cp\u003EBut what is driving this coordinated push and pull?\u003C\/p\u003E\u003Ch3\u003E\u003Cstrong\u003EMaps Versus Barcodes\u003C\/strong\u003E\u003C\/h3\u003E\u003Cp\u003EImam argues that it comes down to how these different parts of the brain are wired before birth.\u003C\/p\u003E\u003Cp\u003EIn the neocortex, neural circuits are organized as spatial maps. Areas that process touch in nearby parts of your body, like your index finger and thumb, are physically close to each other in the brain. The same is true for sight and sound.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EWires in the limbic system, however, are not spatially organized. They function more like a bar code, firing in unique, distributed patterns to represent specific scents or complex memories.\u003C\/p\u003E\u003Cp\u003ETo test whether this was an innate trait or acquired through experience, the team developed AI models for different senses. They found that when they pre-wired an AI with localized, spatial connectivity, the network was naturally very good at processing vision, sound, and touch information. Conversely, distributed, \u201cbarcode-style\u201d networks were essential for the AI to excel at scent recognition and memory.\u003C\/p\u003E\u003Ch3\u003E\u003Cstrong\u003EThe Evolutionary Tug-of-War\u003C\/strong\u003E\u003C\/h3\u003E\u003Cp\u003EThe final piece of the puzzle explains how the size of brain components changes predictably across species. Because resources like space and energy are limited, natural selection chooses which system to prioritize.\u003C\/p\u003E\u003Cp\u003EThe team simulated evolution by creating a multimodal network where the spatial and distributed domains competed for \u201creal estate.\u201d When the environment rewarded smell, all areas of the distributed system expanded and the neocortex shrank. When vision was rewarded, the opposite occurred.\u003C\/p\u003E\u003Cp\u003EThis explains why the nine-banded armadillo, which relies on scent, has a massive limbic system, while the highly visual squirrel monkey is dominated by its neocortex. Across the 182 species studied, the research shows that brain evolution is not about adding new layers of \u0022logic,\u0022 but about strategically reallocating space between different wiring systems to support survival.\u003C\/p\u003E\u003Cp\u003EBy translating this biological architecture to AI systems, engineers could create machines that learn as efficiently as the human brain, requiring far less data and energy.\u003C\/p\u003E\u003Cp\u003E\u201cToday\u0027s artificial neural networks are trained by vast amounts data \u2014 it\u2019s about nurture,\u201d says Imam. \u201cBut the brain is not a blank slate that gets trained by experience. It is a mix of nature and nurture, and the nature is that pre-wired architecture.\u201d\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u201cWe could translate that architecture to AI systems to make it more brain-like, or make it learn or function as efficiently as the brain.\u201d\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThis work was a collaboration with Cornell University and was supported by the National Science Foundation.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EDOI:\u0026nbsp;\u003C\/em\u003E\u003Ca href=\u0022https:\/\/doi.org\/10.1126\/sciadv.aec6112\u0022\u003E\u003Cem\u003Edoi.org\/10.1126\/sciadv.aec6112\u003C\/em\u003E\u003C\/a\u003E\u003C\/p\u003E","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EA new study from Georgia Tech examines how different brain systems scale together across species, offering a new perspective on brain organization \u2014 and its potential applications in artificial intelligence.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"A new study from Georgia Tech examines how different brain systems scale together across species, offering a new perspective on brain organization \u2014 and its potential applications in artificial intelligence."}],"uid":"35575","created_gmt":"2026-06-29 18:27:57","changed_gmt":"2026-07-02 14:56:41","author":"adavidson38","boilerplate_text":"","field_publication":"","field_article_url":"","location":"Atlanta, GA","dateline":{"date":"2026-06-29T00:00:00-04:00","iso_date":"2026-06-29T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"680528":{"id":"680528","type":"image","title":"brain-halves.jpeg","body":"\u003Cdiv\u003EResearchers found that coordinated changes across brain systems may be explained by two distinct wiring strategies \u2014 spatially organized circuits and distributed networks \u2014 that expand and contract together over evolution.\u003C\/div\u003E","created":"1782757701","gmt_created":"2026-06-29 18:28:21","changed":"1782757701","gmt_changed":"2026-06-29 18:28:21","alt":"Digital illustration of a brain surrounded by two distinct visual patterns. One side is composed of structured blue connections resembling an organized network map, while the other features colorful, dispersed light patterns, representing distributed neural activity. The image symbolizes competing brain architectures explored in the study.","file":{"fid":"264802","name":"brain-halves.jpeg","image_path":"\/sites\/default\/files\/2026\/06\/29\/brain-halves.jpeg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/2026\/06\/29\/brain-halves.jpeg","mime":"image\/jpeg","size":5350147,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/2026\/06\/29\/brain-halves.jpeg?itok=7doQLT23"}},"680530":{"id":"680530","type":"image","title":"Fig2.png","body":"\u003Cdiv\u003EA conceptual illustration of the two wiring strategies identified in the study. Spatially organized circuits in the neocortex (left) preserve map-like relationships, while distributed networks in the limbic system (right) connect information across locations, creating a tradeoff that may shape brain evolution.\u003C\/div\u003E","created":"1782758455","gmt_created":"2026-06-29 18:40:55","changed":"1782758455","gmt_changed":"2026-06-29 18:40:55","alt":"A balance scale holds two diagrams representing different brain wiring strategies. The left side shows an ordered rainbow-colored map labeled \u0022Neocortex,\u0022 illustrating localized connections that preserve spatial organization. The right side shows a web of interconnected colored nodes labeled \u0022Limbic System,\u0022 representing distributed connections that integrate information across space. The image symbolizes the tradeoff between these competing neural architectures proposed by the study.","file":{"fid":"264804","name":"Fig2.png","image_path":"\/sites\/default\/files\/2026\/06\/29\/Fig2.png","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/2026\/06\/29\/Fig2.png","mime":"image\/png","size":866124,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/2026\/06\/29\/Fig2.png?itok=7rXvH4XZ"}},"680531":{"id":"680531","type":"image","title":"Fig1-Imam.png","body":"\u003Cp\u003ECross-sections of a squirrel monkey brain (left) and a nine-banded armadillo brain (right) illustrate how different neural systems expand or shrink together across species. The highly visual squirrel monkey has a larger neocortex (blue), while the scent-reliant armadillo has a larger olfactory complex (purple) and memory center (green).\u003C\/p\u003E","created":"1782758808","gmt_created":"2026-06-29 18:46:48","changed":"1782758808","gmt_changed":"2026-06-29 18:46:48","alt":"Comparative brain images showing a squirrel monkey on the left and a nine-banded armadillo on the right. Colored overlays highlight major brain systems: extensive blue neocortical regions in the monkey and enlarged purple olfactory regions in the armadillo, illustrating how different species allocate brain space according to their sensory needs.","file":{"fid":"264805","name":"Fig1-Imam.png","image_path":"\/sites\/default\/files\/2026\/06\/29\/Fig1-Imam.png","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/2026\/06\/29\/Fig1-Imam.png","mime":"image\/png","size":158938,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/2026\/06\/29\/Fig1-Imam.png?itok=dbPFTe7d"}}},"media_ids":["680528","680530","680531"],"groups":[{"id":"66220","name":"Neuro"},{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"194606","name":"Artificial Intelligence"},{"id":"138","name":"Biotechnology, Health, Bioengineering, Genetics"},{"id":"146","name":"Life Sciences and Biology"},{"id":"135","name":"Research"}],"keywords":[{"id":"187915","name":"go-researchnews"},{"id":"172970","name":"go-neuro"}],"core_research_areas":[{"id":"39431","name":"Data Engineering and Science"},{"id":"193656","name":"Neuro Next Initiative"}],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E\u003Cbr\u003EAudra Davidson\u003Cbr\u003EInstitute for Neuroscience, Neurotechnology, and Society\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Contact\u003C\/strong\u003E\u003Cbr\u003E\u003Ca href=\u0022mailto:bwine3@gatech.edu\u0022\u003EBryant Wine\u003C\/a\u003E\u003Cbr\u003ECollege of Computing\u003C\/p\u003E","format":"limited_html"}],"email":["bwine3@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}