Building Blogs of Science

Marsden 2009-I: An eye on the birds and the bees

Posted in Health and Medicine, Science, Science and Society by kubke on October 8, 2009

The projects funded by the Marsden Fund of the Royal Society are out, and there are many interesting neuroscience projects that were funded this year, which I will tell you about over the next few days. Here are the first three.

Ben Thompson, from the University of Auckland will try to teach an old brain new tricks.

Ben Thompson works in amblyopia or “lazy eye”, which affects about 3% of the population. During early development information coming from the two eyes fight for real estate in the visual cortex, and if you have normal vision in the two eyes, the visual cortex receives information from each of the eyes in alternating patches called ocular dominance columns. But if both eyes are providing unequal images then the dominant eye will displace the connections from the weaker eye in the visual cortex.

There is a critical period (which in humans is thought to end between the ages of 5-7 years old) over which treatment of lazy eye can be efficient in restoring normal projections from both eyes to cortex, and it has been traditionally thought that after that there is not enough plasticity in cortex to treat the effects of lazy eye. Some experiments in mice, however, suggested that Prozac could restore some of this plasticity, and this is what Ben wants to investigate. The idea is that if Prozac can restore pre-critical periods of plasticity in the adult brain, then therapies that are effective in children should now also become useful in adults.

The visual cortex has been one of the most intensively studied systems for plasticity in cortex, and if these experiments are successful, then Ben plans to see whether they can be extrapolated to other parts of cortex. For example, inducing plasticity in motor cortex could have a profound impact on the recovery of motor function following stroke.

Gavin Hunt and Russell Gray from the University of Auckland received funding to study tool manufacture and the brains of New Caledonian crows.

That New Caledonian crows were able to use tools had been known for a very long time, but it was Gavin Hunt who first saw these birds manufacture tools while he was doing his PhD in New Caledonia studying the endangered Kagu. He then contacted Russell Gray, and they started what was to become a very fruitful collaboration studying this behaviour.

This time, Gavin and Russell are asking a very interesting question: Did New Caledonian crows evolve a more complex brain associated with tool manufacture?  They plan to investigate the cognitive abilities of different types of crows and to try to identify what is different about the New Caledonian crow brains that makes this behaviour possible. The group has a great webpage where you can see the New Caledonian crow behaviour and two videos where Russell Gray provides a great description of their line of work.

And last but not least,

Alison Mercer from the University of Otago has received funding to study memory formation in bees.

Invertebrates have historically been a fantastic model in which to study fundamental aspects of neuroscience. Despite their small size the brains of bees (and other insects) are quite complex and bees have amazing learning abilities. Alison will look at two types of learning. Aversive learning is that where the bee learns to associate a stimulus with a negative reward. Apetitive learning is that where the bee learns to associate a stimulus with a  positive reward.

There are some differences between these two types of learning. First, apetitive learning develops earlier than aversive learning. Second, aversive learning (but not appetitive learning) can be blocked by a queen bee pheromone. From work in the fruit fly, it is known that these two types of learning are happening on the same population of neurons found in a specialized brain area known as the mushroom body. Since both types of learning are mediated by different neurotransmitters, and since only one type of learning is blocked by the queen’s pheromone, Alison will be able to investigate how a single neuron can create ‘functional’ compartments that allows it to store these two seemingly opposite types of information.

(Disclaimer: Fabiana Kubke is currently funded by the Marsden Fund, is a named investigator  in the New Caledonian project, and personally knows all of the researchers named in this post)

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