{"id":677040,"date":"2026-05-18T07:46:08","date_gmt":"2026-05-18T07:46:08","guid":{"rendered":"https:\/\/www.newsbeep.com\/ca\/677040\/"},"modified":"2026-05-18T07:46:08","modified_gmt":"2026-05-18T07:46:08","slug":"first-objective-framework-for-decoding-fossil-brain-imprints","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ca\/677040\/","title":{"rendered":"First objective framework for decoding fossil brain imprints"},"content":{"rendered":"

A \u2018Rosetta Stone\u2019 for endocasts could aid our understanding of brain development in hominins.<\/p>\n

The fossilized skulls of our ancient ancestors hold faint impressions of the brains that once pressed against them, but reading those marks has been quite subjective. Now, researchers have established a framework, based on comparative imaging data of 75 living people, to decrypt these markings.<\/p>\n

The brain\u2019s surface consists of furrows, called sulci, and ridges, termed gyri, that help increase the brain\u2019s surface area. As the brain presses up against the skull, these structures form marks on the inside of it. For decades, researchers have used these marks in the skulls of our ancestors to better understand the functioning and form of the evolving brain; as the soft tissues of brains do not fossilize, the enduring endocast, marked on the inside of skulls, is essential to this understanding.<\/p>\n

Antoine Balzeau, a researcher at the Mus\u00e9e National d\u2019Histoire Naturelle, Paris, and colleagues used high-resolution MRI technology to directly compare the brain and its resultant endocast in living individuals for the first time ever. The team recruited 75 individuals, as part of the PaleoBRAIN<\/a> project, who underwent MRI at the Piti\u00e9-Salp\u00eatri\u00e8re Hospital, in Paris. While most imaging of fossils nowadays relies on microtomography (micro-CT), the researchers used a specific MRI approach for their study to avoid exposing their participants to radiation.<\/p>\n

Over two years, the team used this data to reconstruct 3D models of the brain, its lining and the endocast.<\/p>\n

\u201cFor 75 individuals, we analyzed all visible marks and were able to identify what they actually correspond to on the underlying brain,\u201d writes Balzeau in an email to Advanced Science News. \u201cThere is no longer any subjectivity: we demonstrate this in every direction and provide access to all 3D models, including numerous endocasts that are perfectly described. This is why we titled this work \u2018the Rosetta Stone of paleoneurology\u2019.\u201d<\/p>\n

In fossil studies, endocasts are often interpreted on the basis of brain atlases<\/a>, which reference uniform, elongated sulcal marks. But each sulcus can branch out in unique ways and, with so much diversity in sulcal patterns across individuals of the same species, endocasts naturally also manifest these variations. \u201cAnd since not all sulci leave marks along their entire length on the inner surface of the skull, the result is a series of short, discontinuous marks, more prevalent toward the lower regions of the brain where contact with the skull is strongest,\u201d adds Balzeau.<\/p>\n

Their findings are contrary to the old ways of analyzing marks on endocasts as long and straight. A more objective understanding of the wide range of features observed in humans could help tease out the differences in brain form and, possibly, function in our ancestors.<\/p>\n

In addition to these differences in the types of marks found, the researchers also came across markings that did not match up with sulci in the brain, which they termed Marks Not Associated with Sulci (MNAS). About 12% of the markings on the endocast, particularly those near its top, fall into this category. While they look akin to markings corresponding to sulci, there were no sulci at the equivalent spots on the brain, suggesting other contributing features may be at play.<\/p>\n

These as-yet unexplained markings can be problematic when analyzing fossil endocasts, with researchers cautioning that interpretations should prioritize well-established markings. \u201cWe propose a conceptual framework and a detailed dataset that allow all researchers to have an objective basis for \u2018reading\u2019 an endocast,\u201d writes Balzeau. This \u2018Rosetta Stone\u2019 for studying endocasts is the first such objective framework. \u201cWhich sulci are most frequently visible on endocasts, which are less so; which regions show the most impressions related to brain sulci, and which are more associated with MNAS \u2013 all of this is explicitly described and richly illustrated. We also provide links to retrieve all the data used to construct this Rosetta Stone.\u201d<\/p>\n

In addition, brain volume is usually measured using the space inside the skull as a proxy; Balzeau\u2019s team found that changes in endocranial volume well-represented changes in brain volume, confirming the assumption that the latter has grown significantly as hominins have evolved.<\/p>\n

Balzeau\u2019s team hopes to take findings on brain anatomy a step further, to understand brain function in ancient humans. Presently, the team has already recorded behavioral information for the study cohort. \u201cThe goal is to understand the potential link between fine-grained aspects of manual laterality\u2014by exploring variations in strength, precision, and dexterity\u2014and bilateral variations in functional brain areas, and therefore in the endocast,\u201d adds Balzeau. Subtle differences in handedness can register as detectable asymmetries in the brain, and potentially on the endocast. \u201cUltimately, this may allow us to better understand the brain anatomy of past human species and to infer aspects of their behavior based on robust scientific data.\u201d<\/p>\n

Reference: Antoine Balzeau et al., The \u2018Rosetta Stone\u2019 of palaeoneurology: A detailed study of the link between the brain and the endocast on 75 volunteers<\/a>, Journal of Anatomy (2026). DOI: https:\/\/doi.org\/10.1111\/joa.70101<\/p>\n

Featured Image Credit: Chelms Varthoumlien (@varlien) via Unsplash<\/p>\n","protected":false},"excerpt":{"rendered":"A \u2018Rosetta Stone\u2019 for endocasts could aid our understanding of brain development in hominins. The fossilized skulls of…\n","protected":false},"author":2,"featured_media":677041,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[49,48,248874,66],"class_list":["post-677040","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ca","tag-canada","tag-journal-of-anatomy","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/677040","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=677040"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/677040\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/677041"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=677040"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=677040"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=677040"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}