Human Brains Caught Wearing New Genes

Whether a person succeeds or not in a competitive modern world, is largely up to the quality of his brain and nervous systems. And that is largely up to his genes — 50% to 80% heritability of IQ, perhaps 90%+ heritability of executive functions.

Thanks to natural selection, human brains have some brave new genes to wear, which seem to make a big difference compared to the mouse.

Compared to mouse brains, human brains wear very new genes

Compared to mouse brains, human brains wear some very new genes

In particular, we found that an excess of young (recently evolved) genes are expressed in the early (fetal or infant) developing human brain compared with those in mouse brain. Expression data covering numerous subregions of the developing brain further demonstrate that these young genes are mainly upregulated in the neocortex. They originated in the evolutionary period during which the neocortex was expanding, suggesting the functional association of new genes with this newly evolving brain structure. Our data reveal that evolutionary change in the development of the human brain happened at the protein level by gene origination and also via evolution of regulatory networks, as intimated by the enrichment of primate-specific transcriptional regulators in our dataset. _

This is very interesting, because we now know that human brain evolution continues to this day — human brains never stopped evolving.

IQ is one important ingredient in life success (PDF). And IQ is up to 80% heritable. Executive functions are another key ingredient in a successful life. And executive functions (EF) may be more than 90% heritable.

There is some correlation between some aspects of IQ and EF but the correlation is limited. The combination of high IQ and strong EF is probably better than either one alone.

Despite the high heritability of both EF and IQ, there is reason to believe that some forms of training — given at the right times — may lead to long term improvements in both EF and IQ.

Psychologists at the University of Oregon designed games to train the network of brain areas involved in attention which undergoes important development between ages 3 and 7. The team of researchers was led by Dr. Michael Posner is a prominent scientist in the field of cognitive neuroscience.

… Using caps wired with electrodes the team recorded children’s brain waves at the beginning and at the end of the study. After training, all the children were again tested on intelligence and attention.

Researchers recorded in Proceedings of the National Academy of Sciences that the network became more efficient after just 5 training sessions. These findings have since been replicated in similar experiments by Spanish researchers.

After the training, Posner reported that 6-year-olds showed a pattern of activity in the anterior cingulate similar to that of adults. “Part of the network developed a more mature response, meaning it looked more like the adult subjects that we’ve also run in these experiments.” Posner said.

The researchers found that even this brief attention training improved one measure of IQ involving non-verbal reasoning. They also show clear post-training improvement on the Kaufman Brief Intelligence Test (KBIT) and in overall IQ, compared with controls. This suggests that they were not only able to train, but that they were able to get generalization–because the KBIT was different from anything they used in the training. __ Neuropath report on Michael Posner’s early childhood attention training

More on the importance of EF to school success

It is important not to fall into the trap of “genetic determinism” regarding the potential of the individual child. If the child is not too badly damaged or disadvantaged, early childhood training of executive functions may advantageously influence how the brain is wired, with long term consequences. We will have to watch and see.

The sensitive developmental periods or “critical windows of development” provide unique opportunities to take advantage of rapid brain plasticity in particular subsystems of the CNS.
[caption id="attachment_174" align="aligncenter" width="500"]Sensitive Developmental Periods Sensitive Developmental Periods

When you consider our modern government educational system in light of the sensitive periods of development, it would seem that the optimal development of most children is neglected, and badly. This means that whatever the genetic potential the child may have for IQ and EF, their potential will not be reached.

Brain development and plasticity begin not long after conception, accelerate rapidly in the womb, and ramp up even more in the first few years of life. But what is the optimal trajectory of brain development and plasticity for each individual child? No one knows.

Natural selection has worked hard to provide human brains with flashy new genes. But are they using them to good effect? Probably not, but what could we be doing better? That is what we need to learn.

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