{"id":3952,"date":"2010-09-03T17:08:53","date_gmt":"2010-09-03T21:08:53","guid":{"rendered":"https:\/\/esa.org\/esablog\/?p=3952"},"modified":"2010-09-03T17:08:53","modified_gmt":"2010-09-03T21:08:53","slug":"worm-brain-sheds-light-on-the-evolution-of-the-cerebral-cortex","status":"publish","type":"post","link":"https:\/\/esa.org\/esablog\/2010\/09\/03\/worm-brain-sheds-light-on-the-evolution-of-the-cerebral-cortex\/","title":{"rendered":"Worm brain sheds light on the evolution of the cerebral cortex"},"content":{"rendered":"

\"\"<\/a><\/p>\n

The last time humans and the marine ragworm Platynereis dumerilii<\/em> shared a common ancestor was roughly 600 million years ago, according to scientists from the European Molecular Biology Laboratory in Heidelberg, Germany (EMBL). That is, researcher have discovered a true counterpart of the cerebral cortex<\/a>, also called the pallium, in this relative of the earthworm. This finding, explained the scientists, could be the key to unraveling the evolution of this important area of the human (and all vertebrates) brain.<\/span><\/p>\n

\u201cTwo stunning conclusions emerge from this finding,\u201d said Detlev Arendt, co-author of the study<\/a> published yesterday in Cell<\/em>, in a press release<\/a>. \u201cFirst, the pallium is much older than anyone would have assumed, probably as old as higher animals themselves. Second, we learn that it came out of \u2018the blue\u2019 \u2013 as an adaptation to early marine life in Precambrian oceans.\u201d<\/span><\/p>\n

The cerebral cortex is a sheet of neural tissue responsible for what is commonly called the \u201cgray matter\u201d of the brain; it plays a key role in memory, attention, perceptual awareness, thought, language and consciousness. According to the release, \u201cour cerebral cortex \u2026 is a big part of what makes us human: art, literature and science would not exist had this most fascinating part of our brain not emerged in some less intelligent ancestor in prehistoric times.\u201d<\/span><\/p>\n

The discovery could provide scientists with a basic understanding of ancient brain centers\u2014what they looked like and how they functioned\u2014and provide insight into the development of the human cerebral cortex. Based on the ragworm\u2019s brain structure, Arendt and colleagues found that the common ancestor\u2019s brain structure was likely a group of densely packed cells which controlled olfactory signals and locomotion. In other words, it may have enabled the ancestors, which were crawling along the sea floor 600 million years ago, \u201cto identify food sources, move towards them and integrate previous experiences into some sort of learning,\u201d as stated in the release.<\/span><\/p>\n

Previous to these findings, scientists believed that the vertebrate brain\u2014as in humans\u2014and invertebrate brain evolved separately along two different paths. That is, insects, spiders and other invertebrates typically have what are known as mushroom bodies\u2014structures similarly responsible for sensory integration and memory. However, by comparing genes from the ragworm\u2019s extra large mushroom body and the human cerebral cortex, the scientists suggested a common ancestor could have started the evolution of both brain structures.<\/span><\/p>\n

\u201cMost people thought that invertebrate mushroom-bodies and vertebrate pallium had arisen independently during the course of evolution, but we have proven this was most probably not the case,\u201d said EMDL colleague Raju Tomer in the release. \u201cThe evolutionary history of our cerebral cortex has to be rewritten,\u201d Arendt concluded.<\/span><\/p>\n

Photo Credit: Natural History Museum<\/p>\n

\n

The last time humans and the marine ragworm Platynereis dumerilii<\/em> shared a common ancestor was roughly 600 million years ago, according to scientists from the European Molecular Biology Laboratory in Heidelberg, Germany (EMBL). That is, researcher have discovered a true counterpart of the cerebral cortex<\/a>, also called the pallium, in this relative of the earthworm. This finding, explained the scientists, could be the key to unraveling the evolution of this important area of the human (and all vertebrates) brain.<\/p>\n

\n<\/p>

\u201cTwo stunning conclusions emerge from this finding,\u201d said Detlev Arendt, co-author of the study<\/a> published yesterday in Cell<\/em>, in a press release<\/a>. \u201cFirst, the pallium is much older than anyone would have assumed, probably as old as higher animals themselves. Second, we learn that it came out of \u2018the blue\u2019 \u2013 as an adaptation to early marine life in Precambrian oceans.\u201d<\/p>\n

\n<\/p>

The cerebral cortex is a sheet of neural tissue responsible for what is commonly called the \u201cgray matter\u201d of the brain; it plays a key role in memory, attention, perceptual awareness, thought, language and consciousness. According to the release, \u201cour cerebral cortex \u2026 is a big part of what makes us human: art, literature and science would not exist had this most fascinating part of our brain not emerged in some less intelligent ancestor in prehistoric times.\u201d<\/p>\n

\n<\/p>

The discovery could provide scientists with a basic understanding of ancient brain centers\u2014what they looked like and how they functioned\u2014and provide insight into the development of the human cerebral cortex. Based on the ragworm\u2019s brain structure, Arendt and colleagues found that the common ancestor\u2019s brain structure was likely a group of densely packed cells which controlled olfactory signals and locomotion. In other words, it may have enabled the ancestors, which were crawling along the sea floor 600 million years ago, \u201cto identify food sources, move towards them and integrate previous experiences into some sort of learning,\u201d as stated in the release.<\/p>\n

\n<\/p>

Previous to these findings, scientists believed that the vertebrate brain\u2014as in humans\u2014and invertebrate brain evolved separately along two different paths. That is, insects, spiders and other invertebrates typically have what are known as mushroom bodies\u2014structures similarly responsible for sensory integration and memory. However, by comparing genes from the ragworm\u2019s extra large mushroom body and the human cerebral cortex, the scientists suggested a common ancestor could have started the evolution of both brain structures.<\/p>\n

\n<\/p>

\u201cMost people thought that invertebrate mushroom-bodies and vertebrate pallium had arisen independently during the course of evolution, but we have proven this was most probably not the case,\u201d said EMDL colleague Raju Tomer in the release. \u201cThe evolutionary history of our cerebral cortex has to be rewritten,\u201d Arendt concluded.<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

The last time humans and the marine ragworm Platynereis dumerilii shared a common ancestor was roughly 600 million years ago, according to scientists from the European Molecular Biology Laboratory in Heidelberg, Germany (EMBL). That is, researcher have discovered a true counterpart of the cerebral cortex, also called the pallium, in this relative of the earthworm. This finding, explained the scientists, could be the key to unraveling the evolution of this important area of the human (and all vertebrates) brain.<\/p>\n","protected":false},"author":50,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[932,933,102,659,934,935],"class_list":["post-3952","post","type-post","status-publish","format-standard","hentry","category-research","tag-brain","tag-cerebral-cortex","tag-evolution","tag-olfaction","tag-ragworm","tag-worm"],"_links":{"self":[{"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/posts\/3952","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/users\/50"}],"replies":[{"embeddable":true,"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/comments?post=3952"}],"version-history":[{"count":0,"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/posts\/3952\/revisions"}],"wp:attachment":[{"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/media?parent=3952"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/categories?post=3952"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/tags?post=3952"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}