Rebuilding the Brain

For many years, it was thought that all of our brain cells (neurons) are produced before birth, or exceptionally, up to one or two years after birth, but then the process supposedly stopped. From then on, most brain scientists believed, brain circuits could only be modified by altering the synapses, or contacts between existing cells. In this view, the total complement of cells, anatomically organized by function and forming major pathways, constituted the brain’s “hardware.” The detailed nature of the relation between cells, the modifiable synapses, was the software.

Starting in the 1960s, evidence suggested that new neurons might be added beyond this early period and even in adulthood. This evidence became compelling in the 1980s, based on observations made while studying parts of the songbird brain involved in the acquisition and production of learned song. The original observations were met with skepticism, but the birdsong data proved compelling.

How does one prove that a neuron was born at a particular time? Each cell in the body contains DNA, which is responsible for producing the proteins that are necessary for a cell’s functioning. Though all cells in the body have the same DNA, only a subset of the genes encoded by the DNA is expressed in each cell type, thus accounting for the difference between, say, a skin cell, a liver cell, and a brain cell.

To continue reading, please log in or enter your email address.

Registration is quick and easy and requires only your email address. If you already have an account with us, please log in. Or subscribe now for unlimited access.

required

Log in

http://prosyn.org/PfFezvL;
  1. Sean Gallup/Getty Images

    Angela Merkel’s Endgame?

    The collapse of coalition negotiations has left German Chancellor Angela Merkel facing a stark choice between forming a minority government or calling for a new election. But would a minority government necessarily be as bad as Germans have traditionally thought?

  2. Trump Trade speech Bill Pugliano/Getty Images .

    Preparing for the Trump Trade Wars

    In the first 11 months of his presidency, Donald Trump has failed to back up his words – or tweets – with action on a variety of fronts. But the rest of the world's governments, and particularly those in Asia and Europe, would be mistaken to assume that he won't follow through on his promised "America First" trade agenda.

  3. A GrabBike rider uses his mobile phone Bay Ismoyo/Getty Images

    The Platform Economy

    While developed countries in Europe, North America, and Asia are rapidly aging, emerging economies are predominantly youthful. Nigerian, Indonesian, and Vietnamese young people will shape global work trends at an increasingly rapid pace, bringing to bear their experience in dynamic informal markets on a tech-enabled gig economy.

  4. Trump Mario Tama/Getty Images

    Profiles in Discouragement

    One day, the United States will turn the page on Donald Trump. But, as Americans prepare to observe their Thanksgiving holiday, they should reflect that their country's culture and global standing will never recover fully from the wounds that his presidency is inflicting on them.

  5. Mugabe kisses Grace JEKESAI NJIKIZANA/AFP/Getty Images

    How Women Shape Coups

    In Zimbabwe, as in all coups, much behind-the-scenes plotting continues to take place in the aftermath of the military's overthrow of President Robert Mugabe. But who the eventual winners and losers are may depend, among other things, on the gender of the plotters.

  6. Oil barrels Ahmad Al-Rubaye/Getty Images

    The Abnormality of Oil

    At the 2017 Abu Dhabi Petroleum Exhibition and Conference, the consensus among industry executives was that oil prices will still be around $60 per barrel in November 2018. But there is evidence to suggest that the uptick in global growth and developments in Saudi Arabia will push the price as high as $80 in the meantime.

  7. Israeli soldier Menahem Kahana/Getty Images

    The Saudi Prince’s Dangerous War Games

    Saudi Arabia’s Crown Prince Mohammed bin Salman is working hard to consolidate power and establish his country as the Middle East’s only hegemon. But his efforts – which include an attempt to trigger a war between Israel and Hezbollah in Lebanon – increasingly look like the work of an immature gambler.