Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Our brains are more like birds' than we thought

05.07.2010
UC San Diego researchers find structural similarities in the neocortices of humans and chickens

For more than a century, neuroscientists believed that the brains of humans and other mammals differed from the brains of other animals, such as birds (and so were presumably better). This belief was based, in part, upon the readily evident physical structure of the neocortex, the region of the brain responsible for complex cognitive behaviors.

A new study, however, by researchers at the University of California, San Diego School of Medicine finds that a comparable region in the brains of chickens concerned with analyzing auditory inputs is constructed similarly to that of mammals.

"And so ends, perhaps, this claim of mammalian uniqueness," said Harvey J. Karten, MD, professor in the Department of Neurosciences at UCSD's School of Medicine, and lead author of the study, published this week in the Proceedings of the National Academy of Sciences Online Early Edition.

Generally speaking, the brains of mammals have long been presumed to be more highly evolved and developed than the brains of other animals, in part based upon the distinctive structure of the mammalian forebrain and neocortex – a part of the brain's outer layer where complex cognitive functions are centered.

Specifically, the mammalian neocortex features layers of cells (lamination) connected by radially arrayed columns of other cells, forming functional modules characterized by neuronal types and specific connections. Early studies of homologous regions in nonmammalian brains had found no similar arrangement, leading to the presumption that neocortical cells and circuits in mammals were singular in nature.

For 40 years, Karten and colleagues have worked to upend this thinking. In the latest research, they used modern, sophisticated imaging technologies, including a highly sensitive tracer, to map a region of the chicken brain (part of the telencephalon) that is similar to the mammalian auditory cortex. Both regions handle listening duties. They discovered that the avian cortical region was also composed of laminated layers of cells linked by narrow, radial columns of different types of cells with extensive interconnections that form microcircuits that are virtually identical to those found in the mammalian cortex.

The findings indicate that laminar and columnar properties of the neocortex are not unique to mammals, and may in fact have evolved from cells and circuits in much more ancient vertebrates.

"The belief that cortical microcircuitry was a unique property of mammalian brains was largely based on the lack of apparent lamination in other species, and the widespread notion that non-mammalian vertebrates were not capable of performing complex cognitive and analytic processing of sensory information like that associated with the neocortex of mammals," said Karten.

"Animals like birds were viewed as lovely automata capable only of stereotyped activity."

But this kind of thinking presented a serious problem for neurobiologists trying to figure out the evolutionary origins of the mammalian cortex, he said. Namely, where did all of that complex circuitry come from and when did it first evolve?

Karten's research supplies the beginnings of an answer: From an ancestor common to both mammals and birds that dates back at least 300 million years.

The new research has contemporary, practical import as well, said Karten. The similarity between mammalian and avian cortices adds support to the utility of birds as suitable animal models in diverse brain studies.

"Studies indicate that the computational microcircuits underlying complex behaviors are common to many vertebrates," Karten said. "This work supports the growing recognition of the stability of circuits during evolution and the role of the genome in producing stable patterns. The question may now shift from the origins of the mammalian cortex to asking about the changes that occur in the final patterning of the cortex during development."

The research was supported by grants from the National Institute of Neurological Disorders and Stroke, the National Institute of Mental Health and the National Institute on Deafness and Other Communications Disorders.

Additional contributors include Yuan Wang of UCSD Department of Neurosciences, the Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle and Agnieszka Brzozowska-Prechtl of the UCSD Department of Neurosciences.

Scott LaFee | EurekAlert!
Further information:
http://www.ucsd.edu

Further reports about: Medicine Neurosciences UCSD cognitive function disorders mammalian brains

More articles from Studies and Analyses:

nachricht Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung

nachricht Scientists reveal source of human heartbeat in 3-D
07.08.2017 | University of Manchester

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Gold shines through properties of nano biosensors

17.08.2017 | Physics and Astronomy

Greenland ice flow likely to speed up: New data assert glaciers move over sediment, which gets more slippery as it gets wetter

17.08.2017 | Earth Sciences

Mars 2020 mission to use smart methods to seek signs of past life

17.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>