Wednesday, July 27, 2011

Smarter Near the Poles, and Nearing Clockwork Orange?

Wired
Humans apparently evolved larger eyes and brains as they migrated closer to the poles. The larger eyes would allow for better adaptation to lower light levels in the wintertime. The larger brains would allow for better adaptation to the greater challenges of radically changing seasons.
Anthropologists at Oxford University collected 55 skulls, dating from the 1800s, that represented 12 different populations from around the globe. The researchers measured the eye socket and brain volumes and plotted them against the latitude of each individual’s country of origin.

The team, lead by the Institute of Cognitive and Evolutionary Anthropology’s Eiluned Pearce, found a significant positive correlation between the size of brain and the latitude of the country. People from the northern-European countries of Scandinavia had the biggest brains, while Micronesians, from just north of the equator, had the smallest. _Wired
While political correctness forces the authors to deny that the larger brains have anything to do with the demonstrated higher intelligences of peoples who migrated farther from the equator, such higher intelligence has been shown to correlate with higher latitude as well as brain size, time after time. HBD (human biodiversity) deniers argue this point out of ignorance, but with the coming of advanced brain imaging techniques which can determine the comparative sizes of some of the very smallest brain nuclei, such denial is becoming infantile at best.

Meanwhile, Cal Tech researchers are homing in on a part of the brain which controls human aggression and violence. We may well be approaching a "Clockwork Orange" scenario, where violence-prone people will be conditioned or modified to remove their violent tendencies.
Our story starts in the hypothalamus, an ancient region of the brain, conserved throughout mammalian evolution. In humans, it is about the size of an almond, housing a motley collection of neurons. These cells regulate distinct bodily functions such as temperature, circadian rhythms, sleep, hunger, thirst, sex, anger, aggression and response to stress. Earlier work showed that electrical stimulation of some of these sites provokes cats and rats to sudden bouts of rage and that the ventromedial hypothalamus (VMH) has some involvement in sexual behaviors. Yet the precise location of attack-promoting neurons, their mode of action, and the interplay between aggression and mating—normally two opposing forms of social interactions—had remained deeply mysterious.

Enter a team from the California Institute of Technology, under the leadership of neurobiologist David J. Anderson. In four steps, the seven scientists, spearheaded by postdoctoral fellow Dayu Lin (now at New York University), nailed down the critical role of aggression neurons in the VMH. The setting was the home cage of an individually housed, sexually experienced male mouse. When another mouse, either a male or a sexually receptive female, entered the cage, the resident male mouse usually attacked the former but mated with the latter. The scientists video recorded the behavior so that the detailed time course of interaction of every pair of animals—the cautious sniffing and retreating, the pushing, shoving and biting, the mounting and consummatory activities—in hundreds of encounters could be statistically analyzed and time-aligned using software developed by machine vision engineers Piotr Dollar and Pietro Perona.

...Stimulating the VMHvl [Editor: The VMHvl is the ventrolateral portion of the ventromedial hypothalamus] when the mouse was by itself did not do anything. Yet in the presence of another animal, the mouse initiated a concerted attack, often by biting the back of the intruder. Unusually for this species, the illuminated male indiscriminately attacked female, castrated male or anesthetized mice—and sometimes even a blown-up latex glove. Aggression ceased once the light stopped. The infection and light delivery had to be targeted to the VMHvl nucleus; stimulating nearby regions did not produce such an effect. It is a striking and immediate demonstration of the link between neurons and behavior. Exciting VMHvl neurons causes aggression.

Finally, Anderson and his team turned to the question of whether the VMHvl cells are necessary for aggression to occur. Using a different technique, they genetically “silenced” VMHvl cells, turning them effectively off for days at a time. This silencing significantly reduced the chances of an aggressive encounter and lengthened the time it took to initiate an attack. _SciAm
The researchers were able to temporarily "dim down" the tendency for the mouse to resort to violence. The techniques for achieving this level of control over the mouse VMHvl nucleus are quite tedious. Eventually the same level of control will be achieved with a nasal spray containing nano-scale capsules of precisely targeted gene modifiers.

Violence is endemic to large parts of Asia, South America, and Africa. And even within the troubled multicultural urban areas of Europe, Oceania, and North America, deadly violence can be a daily phenomenon. Will human authorities utilise the coming tools of behaviour modification, even if they interfere with "free will?" Or is it better to pack prisoners in cages like mammalian sardines, and allow them to do with each other as they wish? The intersection of sophisticated brain and genetic research with widespread sociopathology is likely to prove interesting.

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