Fact or Fiction? mindURbrain

When It Comes to Intelligence, Does Brain Size Matter?

What does brain size say about a creature's mental abilities?

By Kayt Sukel | April 14, 2009 | 13


brain model SIZE DOESN'T MATTER?: It may not be the size of the brain but its organization that matters when it comes to cognitive function.

Research has shown that lead kills neurons (nerve cells), resulting in smaller brains. It has long been hypothesized that such changes in the brain caused by childhood lead exposure may be behind a higher incidence of poor cognitive performance and criminal behavior. And although it is difficult to disentangle the confounding effects of race, class and economics, a recent study by Kim Dietrich, a professor of environmental health at the University of Cincinnati , found that individuals who suffered from the highest lead exposure as children had the smallest brain sizes—as well as the most arrests.

"That early lead exposure was associated with smaller volumes of cortical gray matter [the parts of the brain rich in neural cell bodies and synapses] in the prefrontal area," he says. "And the fact that we saw both criminal behavior and volume loss in this critical area for executive function is probably more than just a coincidence."

That may be so, however, new scientific studies across several animal species, including humans, are challenging the notion that brain size alone is a measure of intelligence. Rather, scientists now argue, it is a brain's underlying organization and molecular activity at its synapses (the communication junctions between neurons through which nerve impulses pass) that dictate intelligence.

Two years ago, Paul Manger, a professor of health sciences at the University of the Witwatersrand in Johannesburg, South Africa, caused quite a stir when he referred to the beloved bottlenose dolphin, owner of a large, nearly human-size brain, as "dumber than a goldfish."

"When you look at cetaceans, they have big brains, absolutely," Manger says. "But if you look at the actual structure of the brain, it's not very complex. And brain size only matters if the rest of the brain is organized properly to facilitate information processing."

He argues that the systems within the brain—how neurons or nerve cells and synapses are organized—are the keys to determining information-processing capacity. Manger speculates that cetacean brains are large not because of intelligence but instead due to an abundance of fatty glial cells (non-nerve cells serving as a supporting tissue), which may be present to provide warmth in cold waters for the information-processing neurons in the brain's interior.

Mark Uhen, a vertebrate paleontologist at the Alabama Museum of Natural History, and Lori Marino, a biologist who studies brain evolution of cetaceans and primates at Emory University's Yerkes National Primate Research Center, disagree. Marino says that Manger's theories discount years of behavioral evidence that show dolphins to be complex thinkers. What's more, she says, the mammals have an unusual brain structure with a different functional map and therefore cannot be compared with other species.

Marino believes that the dolphin's unique brain organization may represent an alternate evolutionary route to complex intelligence—and that molecules released in synapses may provide that alternative path.

A study recently published in Nature Neuroscience by Seth Grant, a neuroscientist at the Wellcome Trust Sanger Institute in Cambridge, along with Richard Emes, a professor in Bioinformatics at Keele University School of Medicine in North Staffordshire, both in England, suggests that all species have the same basic proteins that act in the synapses.

"If you look at us and fish, we have very different cognitive abilities," Emes says. "But we have roughly the same number of these synaptic proteins. It is the number of interactions and gene duplications of these proteins that provide the brain building blocks for higher level cognitive function.”

Emes, Grant and colleagues agree with Marino and Uhenthat intelligence and differences between species are due to molecular complexity at the synaptic level. "The basic dogma says that the computational properties of the brain are based on the number of neurons and synapses," Grant says. "But we modify that by saying that the molecular complexity within those synapses is also important."

Grant and Emes looked at where approximately 150 synaptic proteins were released in the nervous systems of yeast, fruit flies and mice. They found that a variation in production and distribution patterns was linked to higher-level brain organization.

"The proteins that you find in yeast are the sort of proteins that are far more likely to be found expressed throughout the brain in uniform quantities," Grant says. "They laid a foundation to make more diverse and different regions of the brain using different combinations and expressions of other, more innovative proteins." He likens these molecular proteins to implements in a toolbox that help to build specialized brain regions. He goes on to say that the different interactions, duplications or deletions of these proteins resulted over time in the evolutionary development of regions like the prefrontal cortex in humans which is involved in higher executive function like planning and goal-directed behavior

Grant says that this finding offers scientists a new way to approach the study of brain evolution and intelligence and, perhaps more importantly, suggests that looking at sheer brain size has very little to offer in understanding cognitive abilities.

"It's clear now that there are wonderful mental abilities in birds even with their relatively small brains, nerve cells and neural connections. But they have complex molecular synapses," says Grant. "My sense is in the next 10 to 20 years our perspectives about the mental capacities of different species will change quite radically."

But the idea that a big brain equals big smarts is not going to go away anytime soon. Though Manger discounts the role of glial cells in intelligence, a posthumous anatomical study of Albert Einstein's brain showed that the scientific genius's brain differed from the brains of other dead scientists only with its greater ratio of glial cells to neurons. But a study of Einstein's brain organization and synaptic molecule configuration still remains to be completed.

happiness!?

“The greatest degree of inner tranquility comes from the cultivation of love and compassion. The more we care for the happiness of others, the greater is our own sense of well-being.” ~ Dalai Lama

The Wisdom of Einstein. 1879 to 1955

“Few are those who see with their own eyes and feel with their own hearts.”

“Peace cannot be kept by force; it can only be achieved by understanding.”

"Learn from yesterday, live for today, hope for tomorrow. The important thing is not to stop questioning.”

HOW COOL.This could lead to locating brain regions for consciousness. SCIENCE ROCKS.

Real-Time Video: First Look at a Brain Losing Consciousness Under Anesthesia
By Maia Szalavitz Wednesday, June 15, 2011

What happens to your brain as it slips into unconsciousness? A new technique allows researchers to view real-time 3-D images of a patient undergoing anesthesia using the drug propofol, and the findings show that consciousness isn't suddenly switched off, but rather fades as though a dimmer is being dialed down.

The research also suggests that consciousness resides in the connections between multiple parts of the brain, not in any single region. The images show that changes in the anesthetized brain start in the midbrain, where certain receptors for a neurotransmitter called GABA are plentiful.

Read more: http://healthland.time.com/2011/06/15/real-time-video-first-look-at-a-brain-becoming-unconscious-under-anesthesia/#ixzz1PNADA33g

Introducing your brain.

The modern brain is an energy hog. The organ accounts for about 2 percent of body weight, but it uses about 20 percent of the oxygen in our blood and 25 percent of the glucose (sugars) circulating in our bloodstream, according to the American College of Neuropsychopharmacology.

let's use video games to reward loving compassion not aggression! A NO BRAINER

(May 26, 2011) —
"Neural Desensitization to Violence Predicts Increased Aggression Following Violent Video Game Exposure"
Scientists have known for years that playing violent video games causes players to become more aggressive. The findings of a new University of Missouri (MU) study provide one explanation for why this occurs: the brains of violent video game players become less responsive to violence, and this diminished brain response predicts an increase in aggression.

"Many researchers have believed that becoming desensitized to violence leads to increased human aggression. Until our study, however, this causal association had never been demonstrated experimentally," said Bruce Bartholow, associate professor of psychology in the MU College of Arts and Science.

During the study, 70 young adult participants were randomly assigned to play either a nonviolent or a violent video game for 25 minutes. Immediately afterwards, the researchers measured brain responses as participants viewed a series of neutral photos, such as a man on a bike, and violent photos, such as a man holding a gun in another man's mouth. Finally, participants competed against an opponent in a task that allowed them to give their opponent a controllable blast of loud noise. The level of noise blast the participants set for their opponent was the measure of aggression.

The researchers found that participants who played one of several popular violent games, such as "Call of Duty," "Hitman," "Killzone" and "Grand Theft Auto," set louder noise blasts for their opponents during the competitive task -- that is, they were more aggressive -- than participants who played a nonviolent game. In addition, for participants that had not played many violent video games before completing the study, playing a violent game in the lab caused a reduced brain response to the photos of violence -- an indicator of desensitization. Moreover, this reduced brain response predicted participants' aggression levels: the smaller the brain response to violent photos, the more aggressive participants were. Participants who had already spent a lot of time playing violent video games before the study showed small brain response to the violent photos, regardless of which type of game they played in the lab.

"The fact that video game exposure did not affect the brain activity of participants who already had been highly exposed to violent games is interesting and suggests a number of possibilities," Bartholow said. "It could be that those individuals are already so desensitized to violence from habitually playing violent video games that an additional exposure in the lab has very little effect on their brain responses. There also could be an unmeasured factor that causes both a preference for violent video games and a smaller brain response to violence. In either case, there are additional measures to consider."

Bartholow said that future research should focus on ways to moderate media violence effects, especially among individuals who are habitually exposed. He cites surveys that indicate that the average elementary school child spends more than 40 hours a week playing video games -- more than any other activity besides sleeping. As young children spend more time with video games than any other forms of media, the researchers say children could become accustomed to violent behavior as their brains are forming.

"More than any other media, these video games encourage active participation in violence," said Bartholow. "From a psychological perspective, video games are excellent teaching tools because they reward players for engaging in certain types of behavior. Unfortunately, in many popular video games, the behavior is violence."

Other authors in the study include Christopher Engelhardt, graduate student in the MU Department of Psychological Sciences, and researchers from The Ohio State University and VU University of Amsterdam in the Netherlands. The journal article, "This Is Your Brain on Violent Video Games: Neural Desensitization to Violence Predicts Increased Aggression Following Violent Video Game Exposure," will be published in a forthcoming edition of the Journal of Experimental Social Psychology.
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