February 23, 2015 | David F. Coppedge

Adult Brain Can Build New Neurons

A dogma-challenging find raises a question: does the environment create the mind?

A team of Princeton neuroscientists seems intent on finding a naturalistic explanation for a surprising discovery about the brain: “Newborn neurons in the adult brain may help us adapt to the environment.” Medical Xpress explains the problem:

The discovery that the human brain continues to produce new neurons in adulthood challenged a major dogma in the field of neuroscience, but the role of these neurons in behavior and cognition is still not clear. In a review article published by Cell Press February 21st in Trends in Cognitive Sciences, Maya Opendak and Elizabeth Gould of Princeton University synthesize the vast literature on this topic, reviewing environmental factors that influence the birth of new neurons in the adult hippocampus, a region of the brain that plays an important role in memory and learning.

The authors discuss how the birth of such neurons may help animals and humans adapt to their current environment and circumstances in a complex and changing world. They advocate for testing these ideas using naturalistic designs, such as allowing laboratory rodents to live in more natural social burrow settings and observing how circumstances such as social status influence the rate at which new neurons are born.

So was there a clear evolutionary link to this discovery?

Gould and her collaborators recently proposed that stress-induced decreases in new neuron formation might improve the chances of survival by increasing anxiety and inhibiting exploration, thereby prioritizing safety and avoidant behavior at the expense of performing optimally on cognitive tasks. On the other hand, reward-induced increases in new neuron number may reduce anxiety and facilitate exploration and learning, leading to greater reproductive success.

The problem with this explanation is that it explains opposite outcomes.  Fewer neurons inhibit exploration and improve survival. More neurons encourage exploration and improve survival. This flaw in the theory seems to have gone unnoticed by Gould and the team. Here’s what they say they know at this point:

Because many studies that investigate adult neurogenesis use controlled laboratory conditions, the relevance of the findings to real-world circumstances remains unclear.

Did we need PhD’s in neuroscience to tell us that?

So was Gould doing all that work to increase her chances of survival? Find somebody else who does it for seeking truth.

Evolutionary theorizing is a complete waste of time. Let them play with their rodents; that’s OK. But trying to tie a finding to a Darwinian fable reduces their explanation to the Stuff Happens Law. Everybody already knows that one by experience.


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