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Northwestern University: Embargoed for release: 21-Nov-2007 12:00 Eastern US Time
Molecular foreman in the brain
Scientists have found a master molecule in the brain. It runs the show when connections
between brain cells are being remodelled - which is how we learn new information
When the mechanism the scientists have found goes wrong the result may be mental retardation, schizophrenia or drug addiction. So this new discovery could improve
our understanding of these disorders of the brain.
Peter Penzes and his colleagues published their findings in the November 21, 2007,
issue of the journal Neuron, published by Cell Press.
Brain cells are known as neurons by scientists. In these new experiments, the researcherstried to understand what controls the growth of dendriticspines on neurons. These
are the receiving stations for signals sent from nearby brain cells.
When a brain is learning, signalling between these spines increases. This lays down
memories in the brain. Spines can also play a part in brain disorders. Badly formed
dendriticspines have been found in autistic spectrum disorders, schizophrenia, ADHD
and drug addiction.
Penzes and his colleagues were trying to discover if a molecule called kalirin-7
plays a role in spine growth in matureneurons during long-term potentiation (LTP).
Their theory was that kalirin-7 regulates the growth of the spines. Evidence for
this is its high concentration in the spines of matureneurons. Also kalirin-7 was
known to play a role in the remodelling of the overall structure of the cell - the
The researchers carried out their experiments with neurons in culture. These showed
that activation of neurons during long-term potentiation does indeed trigger kalirin-7
to turn on the machinery for remodelling the spines. This makes them grow larger.
They also found that kalirin-7 regulates the other main process that strengthens
signalling between neurons. It controls the number of receptors. These are found
all over the surface of dendriticspines. They act as receiving stations for neurotransmitters.
The strength of signalling between neurons depends on the number of receptors they
have on them.
These new findings, say Perez and his colleagues, strongly suggest that kalirin-7
plays “an important role in learning and memory.”
They also point out that altered spine structures “have been associated with mental retardation, neuropsychiatric disorders, and drug addiction.
“Therefore, our results may suggest potentialstrategies for treatments of these
neurodevelopmental and psychiatric diseases,” they write.
More help with words
What's it all about?
In which part of the body have scientists have found an important molecule?
Did the scientists study neurons inside somebody's brain?
Where did they study them?
They found that kalirin-7 had two jobs to do when long term memories were being formed.
State one of these.
As well as increasing our understanding of how memories are made, what other applications
might there be for this new discovery?
If you were these scientists what questions would you still have about what this
Briefly outline an experiment that might help you to answer that question.
More learning and teaching resources
University of Washington Television has an online video of a teacher/scientist introducing
youngsters to the workings of the brain. Show the class the section on neurons and
how they communicate with each other that starts 8 minutes 15 seconds in and lasts
just over 4 minutes.
Then invite students, working in groups, to use what they have just seen and heard,
and what they have learned from the links to this article, to sketch the three brain
cells in the video demonstration.
They should label the different parts of each cell and draw arrows to show the direction
of a signal - along the different parts of a cell and from one cell to another.
For groups that need a hand to get started, you can tell them that the following
parts should be shown in their diagram:
dendrites (or dendritic spines)
And the arrows for the signals should be labelled either 'electrical signal' or 'chemical
Once the diagrams have been sketched, groups should give a short explanation or demonstration
to the class.