More than just auditory cheesecake

In his 1997 book How the Mind Works, Canadian linguist and cognitive scientist Steven Pinker famously described music as 'auditory cheesecake', a nice enough thing but not one that is necessary to the functioning of human life or society.

Music is "an exquisite confection crafted to tickle the sensitive spots of at least six of our mental faculties," he wrote, but it is merely a fortunate byproduct of the development of the modern mind rather than the evolutionary great leap forward that language was.

Others, including the British archaelogist Steven Mithen in The Singing Neanderthal, argue differently, believing our ancestors had a proto-language, a single evolutionary precursor to both language and music, and that we have retained both strands as separate and yet overlapping methods of communication.

Professor Alan Harvey, chair of the University of Western Australia's neuroscience discipline, invited speaker at the Australian Neuroscience Society annual meeting in Hobart this week and keen musician, is more inclined to follow the latter camp.

Harvey has been threatening to write a book about his theories of music and the evolution of the modern mind for a decade, and he might just go through with it. He has recently written an article for Music Forum, the journal of the Music Council of Australia, encapsulating his thoughts, and is keen to assist in efforts to bring music into the mainstream of cognitive neuroscience by bringing together the science and the evolutionary story into one narrative.

"This is something that people have thought about for three or four thousand years - what music is, why we respond to it, how it has its impact on us, why it is universal," Harvey says.

"Why is it that every group or tribe or nation has music as part of ceremonies and rituals? I actually think that it has profound roles in human communication, especially group communication. What I'll talk about [at the ANS meeting] is how music is processed in the brain, how it relates to language processing, how old we are and when did we evolve language and music, and discuss possible reasons why we retained these two strands of communication."

Researchers in the field such as Mithen believe there is what is called a musi-language, or proto-language, that is mimetic rather than linguistic. Harvey points to the intriguing links between manual gestures and language, for example the role of Broca's area in both speech and complex hand movements.

"We tend to think of Broca's as a motor speech area but it's much more than that," he says. "Then the question is, how recently did we acquire language? And if we acquired language, why did we retain music, which has some overlap in its brain processing but also has some distinct circuitries as well - that's why you get things like amusia. This is what Oliver Sachs writes about - you can lose the ability to process music but not language and vice versa.

"The controversial element in all this is that it may be that without music, the wonder of language and the evolution of consciousness that goes with it was difficult to handle without some compensatory cognitive system that broke down the barriers between individuals. We know that it's involved in group activities, that between mother and infant language is essentially musical, we know that it's involved in all sorts of collective thinking and expression.

"I think the reason it has been preserved is that it's an essential part of our modern cognitive make-up. Some of the areas that are activated in the brain that are involved in things like altruistic acts and reward acts, we can now map. Some of the areas that are activated overlap with areas that are activated when you listen to music you like. They are also activated when you look at erotica. This isn't coincidental at all, in my opinion."

---PB--- Day job

Music certainly seems to run in Harvey's genes - his cousin is the Scottish-born, Australian-based singer-songwriter Eric Bogle - but it is neuroscience that he is most well known for.

It wasn't music he was interested in studying when he started his scientific career, but vision. He studied physiology as an undergraduate at Cambridge University, where he had the great good fortune to have lecturers such as Colin Blakemore, Horace Barlow and Fergus Campbell, all big names in the vision field.

He came to Australia to study with the group led by Peter Bishop at the John Curtin School of Medical Research at ANU, worked as a postdoc in the US for three years and spent some time at Flinders University, eventually ending up at UWA, where he has been resident for more than two decades.

At UWA, Harvey is part of the Neurotrauma Research Program and works in several areas: a gene therapy project using viral vectors to insert genes for growth factors to repair retinal ganglion cells in the eye; looking at glial cells and their biology; and another looking at pharmacological agents that interfere with growth inhibitory factors in the central nervous system. He is also a project leader in the WA Centre of Excellence for Alzheimer's Disease Research and Care, directed by Professor Ralph Martins.

Harvey works closely with Dr Giles Plant at UWA on an olfactory ensheathing glia project, an area that is of great interest around the world due to the potential of using these cells in the regeneration and remyelination of the spinal cord.

"There are clinical trials going on at the moment, but there is a lot of controversy over whether these cells can myelinate axons or not," Harvey says. "In the models that Giles has developed, we really can't get them to myelinate in vitro, in conditions where Schwann cells can. This is really Giles' work.

"They do make myelin-related proteins, and in vivo there is some evidence that they can myelinate. It is still controversial because it all comes down to having to be absolutely certain about identifying the cells that you have and whether the myelin that is associated with these cells truly comes from them. If they do myelinate, it is very odd that they don't myelinate in their normal environment, the olfactory nerve."

In the gene therapy project, he and Plant have been collaborating with Professor Joost Verhaagen of the Netherlands Institute for Neuroscience, and one of Verhaagen's former graduate students, Dr Marc Ruitenberg, who is now at UWA. Plant's group is predominantly looking at the spinal cord, while Harvey is looking at the visual system.

"We've published work on brain derived neurotrophic factor (BDNF); neurotrophin-3; ciliary derived neurotrophic factor (CNTF) and glial cell-line derived neurotrophic factor. We've engineered retinal ganglion cells with the adeno-associated virus (AAV).

"One of the AAV serotypes is quite efficient at transducing retinal ganglion cells and we've shown that CNTF enhances survival and regeneration of injured retinal ganglion cells quite significantly. BDNF enhances survival but it doesn't enhance regeneration."

Harvey and his team have found that CTNF is the most effective gene for regenerating injured cells but that it does have its drawbacks, such as causing changes to the photoreceptors. The NRP has begun a large project, led by Dr Jenny Rodger, to fill transduced ganglion cells with dyes to study their dendritic architecture. While transduced neurons may show regenerative axon growth, their morphology also seems to change over time, which is not a good idea in a functional sense.

There is also work on gene silencing, predominantly by another colleague, Dr Cui Qi (now in Hong Kong), who is using RNAi techniques. This is another area where there are downsides, Harvey says.

"There are lots of imponderables with RNAi - how much do you need to inhibit to get a functional readout? And it might depend on the protein, it might depend on the cell, it might depend on whether the cell compensates, as there must be feedback from the cytoplasm to the nucleus to say we need more RNA - so if you actually knock it down, can the cell then respond by upregulating gene expression over a period of time?

"I don't think we know much of that. Unfortunately, you don't get money for investigating downsides, but somebody has to do it, especially when clinical trials are in the offing."

---PB--- Born to be wild

Another downside might be Harvey's unfathomable liking for Cliff Richard, but this is balanced by a feel for the quality music he plays with his band, Chain Reaction (you can see them on YouTube - their Born to be Wild is great).

Music, for Harvey, allows us to "momentarily forget our isolation and mortality. We forget the brutal high beam of consciousness that transfixes us, that reminds us that one day we will no longer be." Without this counterweight of music, we may not have been able to deal with this high beam.

People think of music as art, not as a core element of human cognitive life, he says. It is often only a voluntary add-on in schools. "If in fact you buy the idea that there is a rational, evolutionary basis for retaining two strands of communication, as counterbalances to each other, and that this was important when we evolved - we still have it, we still respond to it, it is still a critical part of life - what is odd then is that neurologists don't use music in their armamentarium. When you have people who are depressed, who have an affective mood problem, why wouldn't you use music to help evaluate their mental state?

"Music needs to be put into the mainstream of cognitive neuroscience. There is no question that musical therapy works but to many it seems sort of 'alternative'. As a scientist, I want to try and persuade the science profession that this is not alternative - it is real. When it comes down to it, the subtext is that without music there might not have been a successful modern mind."