Part of the show The Genetics of Brain and Behaviour
Itís time to take a look at the top stories from this month, I join PhD student David Weston from Cambridge University. Heís been busy shifting through neuroscience research and comes up with his three favourite papers from the month....
David - So the first paper Iíd like to talk about has really set the scientific community buzzing. It was published this week in the journal Nature by Luis Parada and his group over in the United States. The group were able to identify a specific subset of cells growing within brain tumours, a kind of cancer stem cell and these cells are thought to be responsible for the regrowth of tumours after chemotherapy.
Hannah - So these cells could be the reason that tumours regrow even after chemotherapy. But how did the scientists find out about these new cells?
David - Well the scientists used a genetically engineered mouse model to fluorescently label this subpopulation of cells and track their survival during a course of chemotherapy and what they found was that while chemotherapeutic drugs managed to kill cells in the tumour, it failed to kill this small subpopulation. What they then went on to show was that when the tumour regrew the new tumour cells that were made were derived from these chemo-therapy resistant cells.
Hannah - So these cells are the parent cells of new tumour cells. Why do you think this discover is so critical in our understanding of cancer?
David - Well the results of this study seem to suggest that there may be a kind of cancer stem cell that could drive tumour growth, which has been a controversial idea in the field. Now that these cells have been identified we might be able to specifically target this them with drugs and stop the tumours from regrowing.
David - The next paper I want to talk about gives support to the idea that you can learn while youíre asleep. People have long thought that one of the primary purposes of sleep is the consolidation of memory, so the cementing of information in your mind, but this week Ken Paller and his colleagues at Northwestern University, have shown that this process of consolidation is enhanced if you also learn while you sleep.
Hannah - So learning while you sleep might not be a myth after all but how did Paller test this theory?
David - Well Paller and his colleagues taught 16 volunteers to play two different musical phrases using the keys on a computer keyboard and visual cues from a computer. They then let the subjects have an afternoon nap and when they entered a deep sleep one of the melodies they had been practicing that morning was played to them. Now when the subjects were tested after their nap they found that their accuracy for both of the melodies was better than before, but more importantly the accuracy for the melody that was playing while they were asleep was dramatically increased.
Hannah - So it seems that playing one of the melodies while the participants slept improved their abilities. Letís hope that this kind of enhancement can carry over to other forms of information.
David - The final paper Iíd like to talk about describes what happens to the brain when you learn a second language. Now a lot of people say that itís easier to learn languages when youíre younger because your brain is much more adaptable but the authors of this next paper, working at Dartmouth College, show evidence that even learning a second language as an adult can make big changes to the brain.
Hannah - So learning a new language can cause structural changes in the brain. How did the authors of this paper actually measure the changes in the brain?
David - Well Peter Tse and his colleagues used a brain imaging technique called diffusion tensor imaging which is a type of MRI scan that measures the diffusion of water in the white matter nerve tracts of the brain. Now the scientists took monthly images of the brains of 27 people. Of those 27 people, 11 people were put on an intensive Modern Standard Chinese language course and what the researchers found was that the brains of the people learning the new language had changed over the 9 months of the course compared to the control group.
Hannah - What was so different about the brains of those on the language course compared to the others and why is it important?
David - The language learners showed changes in areas of the brain associated with language acquisition, as they had expected but they also found that areas of the frontal cortex, the area right at the front of the brain were changed. This finding really challenges the idea that the adult brain is not adaptable and shows that changes to the brain are important for acquiring new information in the form of learning a new language.
Hannah - Exciting results showing that at any age we can exercise our brains by picking up a new skill, like learning a new language, and this changes the connectivity of our brains. That last paper was published by Chlegel and collegues in Journal of Cognitive Neuroscience.