Why Teens Are More Prone to Addiction, Mental Illness

By comparing the brain's response to a food reward in adult and teen rats, researchers have pinpointed some differences that might explain why adolescents take more risks and are more prone to addiction, depression and schizophrenia.

"The brain region that is very critical in planning your actions and in habit formation is directly tapped by reward in adolescents, which means the reward could have a stronger influence in their decision-making, in what they do next, as well as forming habits in adolescents," study researcher Bita Moghaddam, of the University of Pittsburgh, told LiveScience. "

Teenagers could do stupid things in response to a situation not because they are stupid, but because their brains are working differently. Somehow they perceive and react to a situation differently." The study was performed in rats, but teenagers throughout the animal kingdom show the same risk-taking and impulsive behaviors as human teens, so the results are likely to be applicable in humans too, the researchers said.

Other studies show that the teen brain is also more susceptible to stress than the adult brain. Teenage brains are especially susceptible to addiction and mental illness, and the differences in the brain at that time may play a big role in these diseases. "If your brain is processing the exact same thing differently, that could give us clues as to why their brain is more vulnerable," Moghaddam said. "By understanding what is happening in the brains of adolescents we can better understand how to prevent disease."

Continued: http://www.livescience.com/17938-teens-prone-addiction-mental-illness.html

Prehistoric Human Brain Found Pickled in Bog

A brain in near-perfect condition is found in a skull of a person who was decapitated over 2,600 years ago.

By Jennifer Viegas
Wed Apr 6, 2011 05:30 AM ET

THE GIST

• One of the world's best preserved prehistoric human brains was recently found in a waterlogged U.K. pit.
• The brain belonged to an Iron Age man who was hanged and then decapitated, with his head falling in the pit shortly thereafter.
• Scientists believe that submersion in liquid, anoxic environments helps to preserve human brain tissue.

A human skull dated to about 2,684 years ago with an "exceptionally preserved" human brain still inside of it was recently discovered in a waterlogged U.K. pit, according to a new Journal of Archaeological Science study.

The brain is the oldest known intact human brain from Europe and Asia, according to the authors, who also believe it's one of the best-preserved ancient brains in the world.

"The early Iron Age skull belonged to a man, probably in his thirties," lead authorSonia O'Connor told Discovery News. "Cause of death is rarely possible to determine in archaeological remains, but in this case, damage to the neck vertebrae is consistent with a hanging."

SLIDE SHOW: Faces of Our Ancestors

"The head was then carefully severed from the neck using a small blade, such as a knife," added O'Connor, a post-doctoral research associate at the University of Bradford. "This was used to cut through the throat and between the vertebrae and has left a cluster of fine cut marks on the bone."

The brain-containing skull was found at Heslington, Yorkshire, in the United Kingdom. O'Connor and her team suspect the site served a ceremonial function that persisted from the Bronze Age through the early Roman period. Many pits at the site were marked with single stakes. The remains of the man were without a body, but the scientists also found the headless body of a red deer that had been deposited into a channel.

Laser imaging, chemical analysis and other examinations revealed that the brain naturally preserved over the millennia. The scientists found no evidence for bacterial or fungal activity, and described the tissue as being "odorless…with a resilient, tofu-like texture."

The condition of the brain is remarkable for its age.

NEWS: Prehistoric Jewelry Reveals Neanderthal Fashion Sense

"In the air, even in the chill of a hospital mortuary, brain tissue very quickly decays to liquid before muscle and other soft tissues show much evidence of decay," O'Connor said.

She and her colleagues suggest that a fortuitous series of events -- for the brain and science, not the victim -- led to the organ's preservation. Shortly after the man was killed, his head must have been placed, or fallen into, the waterlogged pit that was free of oxygen. While other soft human body parts may not preserve well under such conditions, the wet environment appears to be perfect for keeping brains "fresh," "due to the very different chemistry of brain tissue," O'Connor said.

The researchers don't think the violent way the man was killed aided his brain's preservation. While severing his head separated it from the rest of his body, including the bacteria-filled gut, the decapitation "would also have produced a gaping wound that would have been open to immediate infection from micro-organisms involved in putrefaction." The quick burial in conditions not suited for microbial activity likely prevented that from happening.

NEWS: Humans Weren't Always at the Top of the Food Chain

In addition to describing this unusually well preserved brain, the journal paper provides the first in-depth study of other prehistoric human brains and soft human tissues discovered by scientists. They include the body of the 5,000-year-old Tyrolean "Ice Man," the Inca mummies of the high Andes, the tanned bog bodies from across Northern and Western Europe, good condition bodies sealed in lead coffins -- such as the St. Bees man, and crypt burials at places like Spitalfields Church, London, where bodies with surviving brain tissue were found.

Glen Doran, chair of the anthropology department at Florida State University, told Discovery News that two aspects of the new study immediately struck him as "notable."

"First," he said, "such preservation is testimony to the amazing preservation in wet sites. Truly amazing things come out of the muck."

"The second, he added, "is the absolutely stellar analysis brought to bear on this special find."

NEWS: Stone Age Fertility Ritual Object Found

Based on this discovery and other known prehistoric, intact human brains, he agrees that rapid burial in an aqueous environment, as well as near-continual submersion, are essential to human brain tissue preservation.

"The cranium is well designed to protect the brain in life and can, under the right circumstances, remain on duty long after the normal expectation of service," he said.

http://news.discovery.com/archaeology/preserved-brain-bog-england-110406.html

Neanderthal brains

The brains of Neanderthals and modern humans developed differently09 November 2010 Max-Planck-Gesellschaft

Researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany have documented species differences in the pattern of brain development after birth that are likely to contribute to cognitive differences between modern humans and Neanderthals.
Whether cognitive differences exist between modern humans and Neanderthals is the subject of contentious disputes in anthropology and archaeology. Because the brain size range of modern humans and Neanderthals overlap, many researchers previously assumed that the cognitive capabilities of these two species were similar. Among humans, however, the internal organization of the brain is more important for cognitive abilities than its absolute size is. The brain’s internal organization depends on the tempo and mode of brain
development.

Based on detailed measurements of internal shape changes of the braincase during individual growth, a team of scientists from the MPI has shown that these are differences in the patterns of brain development between humans and Neanderthals during a critical phase for cognitive development.

Discussions about the cognitive abilities of fossil humans usually focus on material culture (e.g. the complexity of the stone tool production process) and endocranial volumes. "The interpretation of the archaeological evidence remains controversial, and the brain-size ranges of Neanderthals and modern humans overlap," says Jean-Jacques Hublin, director of the Department of Human Evolution at the MPI-EVA in Leipzig where the research was conducted. Hublin adds, "our findings show how biological differences between modern humans and Neanderthals may be linked to behavioural differences inferred from the archaeological record."

Nature of the evidence: As the brain does not fossilize, for fossil skulls, only the imprints of the brain and its surrounding structures in the bone (so called "endocasts") can be studied. The researchers used state-of-the-art statistical methods to compare shape changes of virtual endocasts extracted from computed-tomographic scans. The distinct globular shape of the braincase of adult Homo sapiens is largely the result of a brain development phase that is not present in Neanderthals.

One of the key pieces of evidence was the skull reconstruction of a Neanderthal newborn. In 1914, a team of French archaeologists had excavated the skeleton of a Neanderthal baby at the rock shelter of Le Moustier in the Dordogne. The original bones of the skeleton had been lost to science for more than 90 years, until they were rediscovered among museum collections by Bruno Maureille and the museum staff. The restored original baby bones are now on permanent display at the Musée National de Préhistoire in Les Eyzies-de-Tayac- Sireuil. The museum’s director Jean-Jacques Cleyet-Merle made it possible to scan the delicate fragments using a high-resolution computed-tomographic scanner (µCT). Using computers at the Max Planck Institute’s virtual reality lab in Leipzig, Philipp Gunz and Simon Neubauer then reconstructed the Neanderthal baby from the digital pieces, like in a three-dimensional jigsaw puzzle. "When we compare
the skulls of a Neanderthal and a modern human newborn, the Neanderthal’s face is already larger at the time of birth. However, most shape differences of the internal braincase develop after birth," explains Gunz. Both Neanderthals and modern human neonates have elongated braincases at the time of birth, but only modern human endocasts change to a more globular shape in the first year of life. Modern humans and Neanderthals therefore reach large adult brain sizes via different developmental pathways.

In a related study the same team of MPI researchers had previously shown that the developmental patterns of the brain were remarkably similar between chimpanzees and humans after the first year of life, but differed markedly directly after birth. "We interpret those aspects of development that are shared between modern humans, Neanderthals, and chimpanzees as conserved," explains Simon Neubauer. "This developmental pattern has probably not changed since the last common ancestor of chimpanzees and humans several million years ago." In the first year of life, modern humans, but not Neanderthals, depart from this ancestral pattern of brain development.

Establishing when the species differences between Neanderthal and modern human adults emerge during development was critical for understanding whether differences in the pattern of brain development might underlie potential cognitive differences. As the differences between modern humans and Neanderthals are most prominent in the period directly after birth, they likely have implications for the neuronal and synaptic organization of the developing brain.

The development of cognitive abilities during individual growth is linked to the maturation of the underlying wiring pattern of the brain; around the time of birth, the neural circuitry is sparse in humans, and clinical studies have linked even subtle alterations in early brain development to changes in the neural wiring patterns that affect behaviour and cognition. The connections between diverse brain regions that are established during this period in modern humans are important for higher-order social, emotional, and communication
functions. It is therefore unlikely that Neanderthals saw the world as we do.

The new study shows that modern humans have a unique pattern of brain development after birth, which separates us from our closest relatives, the Neanderthals. This uniquely modern human pattern of early brain development is particularly interesting in light of the recent breakthroughs in the Neanderthal genome project. A comparison of Neanderthal and modern human genomes revealed several regions with strong evidence for positive selection within Homo sapiens, i.e. the selection occurred after the split between modern humans and
Neanderthals. Three among these are likely to be critical for brain development, as they affect mental and cognitive development.

"Our findings have two important implications," says Philipp Gunz. "We have discovered differences in the patterns of brain development that might contribute to cognitive differences between modern humans and Neanderthals. Maybe more importantly, however, this discovery will tell us more about our own species than about Neanderthals; we hope that our findings will help to identify the function of some genes that show evidence for recent selection in modern humans."

http://goto.mpg.de/mpg/news/201011021/

Neanderthal brains

The brains of Neanderthals and modern humans developed differently09 November 2010 Max-Planck-Gesellschaft

Researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany have documented species differences in the pattern of brain development after birth that are likely to contribute to cognitive differences between modern humans and Neanderthals.
Whether cognitive differences exist between modern humans and Neanderthals is the subject of contentious disputes in anthropology and archaeology. Because the brain size range of modern humans and Neanderthals overlap, many researchers previously assumed that the cognitive capabilities of these two species were similar. Among humans, however, the internal organization of the brain is more important for cognitive abilities than its absolute size is. The brain’s internal organization depends on the tempo and mode of brain
development.

Based on detailed measurements of internal shape changes of the braincase during individual growth, a team of scientists from the MPI has shown that these are differences in the patterns of brain development between humans and Neanderthals during a critical phase for cognitive development.

Discussions about the cognitive abilities of fossil humans usually focus on material culture (e.g. the complexity of the stone tool production process) and endocranial volumes. "The interpretation of the archaeological evidence remains controversial, and the brain-size ranges of Neanderthals and modern humans overlap," says Jean-Jacques Hublin, director of the Department of Human Evolution at the MPI-EVA in Leipzig where the research was conducted. Hublin adds, "our findings show how biological differences between modern humans and Neanderthals may be linked to behavioural differences inferred from the archaeological record."

Nature of the evidence: As the brain does not fossilize, for fossil skulls, only the imprints of the brain and its surrounding structures in the bone (so called "endocasts") can be studied. The researchers used state-of-the-art statistical methods to compare shape changes of virtual endocasts extracted from computed-tomographic scans. The distinct globular shape of the braincase of adult Homo sapiens is largely the result of a brain development phase that is not present in Neanderthals.

One of the key pieces of evidence was the skull reconstruction of a Neanderthal newborn. In 1914, a team of French archaeologists had excavated the skeleton of a Neanderthal baby at the rock shelter of Le Moustier in the Dordogne. The original bones of the skeleton had been lost to science for more than 90 years, until they were rediscovered among museum collections by Bruno Maureille and the museum staff. The restored original baby bones are now on permanent display at the Musée National de Préhistoire in Les Eyzies-de-Tayac- Sireuil. The museum’s director Jean-Jacques Cleyet-Merle made it possible to scan the delicate fragments using a high-resolution computed-tomographic scanner (µCT). Using computers at the Max Planck Institute’s virtual reality lab in Leipzig, Philipp Gunz and Simon Neubauer then reconstructed the Neanderthal baby from the digital pieces, like in a three-dimensional jigsaw puzzle. "When we compare
the skulls of a Neanderthal and a modern human newborn, the Neanderthal’s face is already larger at the time of birth. However, most shape differences of the internal braincase develop after birth," explains Gunz. Both Neanderthals and modern human neonates have elongated braincases at the time of birth, but only modern human endocasts change to a more globular shape in the first year of life. Modern humans and Neanderthals therefore reach large adult brain sizes via different developmental pathways.

In a related study the same team of MPI researchers had previously shown that the developmental patterns of the brain were remarkably similar between chimpanzees and humans after the first year of life, but differed markedly directly after birth. "We interpret those aspects of development that are shared between modern humans, Neanderthals, and chimpanzees as conserved," explains Simon Neubauer. "This developmental pattern has probably not changed since the last common ancestor of chimpanzees and humans several million years ago." In the first year of life, modern humans, but not Neanderthals, depart from this ancestral pattern of brain development.

Establishing when the species differences between Neanderthal and modern human adults emerge during development was critical for understanding whether differences in the pattern of brain development might underlie potential cognitive differences. As the differences between modern humans and Neanderthals are most prominent in the period directly after birth, they likely have implications for the neuronal and synaptic organization of the developing brain.

The development of cognitive abilities during individual growth is linked to the maturation of the underlying wiring pattern of the brain; around the time of birth, the neural circuitry is sparse in humans, and clinical studies have linked even subtle alterations in early brain development to changes in the neural wiring patterns that affect behaviour and cognition. The connections between diverse brain regions that are established during this period in modern humans are important for higher-order social, emotional, and communication
functions. It is therefore unlikely that Neanderthals saw the world as we do.

The new study shows that modern humans have a unique pattern of brain development after birth, which separates us from our closest relatives, the Neanderthals. This uniquely modern human pattern of early brain development is particularly interesting in light of the recent breakthroughs in the Neanderthal genome project. A comparison of Neanderthal and modern human genomes revealed several regions with strong evidence for positive selection within Homo sapiens, i.e. the selection occurred after the split between modern humans and
Neanderthals. Three among these are likely to be critical for brain development, as they affect mental and cognitive development.

"Our findings have two important implications," says Philipp Gunz. "We have discovered differences in the patterns of brain development that might contribute to cognitive differences between modern humans and Neanderthals. Maybe more importantly, however, this discovery will tell us more about our own species than about Neanderthals; we hope that our findings will help to identify the function of some genes that show evidence for recent selection in modern humans."

http://goto.mpg.de/mpg/news/201011021/