Friday, 20 December 2013

The Musical Brain

2013 BNA Christmas Symposium overview

by Jonathan Smith

How does the human brain distinguish music from noise? What brain regions are active when we react to music? Do we all share an intrinsic musicality? How do you make a duck into a soul singer?

These important questions were discussed this month in an annual Christmas symposium held by the British Neuroscience Association (BNA). Speakers from all over the UK were invited to present their findings on the special relationship between Homo sapiens and music. These talks were also interspersed with live music, refreshments and humorous ‘Christmas Crackers’ such as the latter question asked above. In this article I summarise the research discussed in this exciting symposium.

Distinguishing music from noise by pattern-detection
It’s rare to be in a completely silent environment, even in university exams! Being able to tell apart rhythm from random noise is very advantageous. This is because we can be alerted to someone’s footsteps for example, which can let us calculate all sorts of useful information such as the proximity, speed and even mood of the walker.

Dr Maria Chait from the University College London (UCL) demonstrated that humans are incredibly sensitive to rhythmic, repeating sounds. This is even the case when our attention is diverted to other tasks - showing that there is continuous, sub-conscious processing that is very effective at detecting rhythms in our auditory inputs. This might go some way to explaining why all human societies feature some form of rhythmic musical tradition, including genres like polyrhythmic African drumming and thumping dance floor beats.

The Beat in society
It’s clear that an important component of most music is a regular pulse, or beat. The beat provides a regular structure on which we can build harmonies, rhythms and melodies. As demonstrated by the audience in a clapping task, humans are very good at detecting the beat of a piece of music and then moving in sync with it - in other words, dancing. Any Youtube video search would also reveal that our fascinating ability starts at an early age. What is happening in the brain when we detect a beat?

In studies by Dr Katie Overy of the University of Edinburgh, participants were tested to see if they could tell if the beat was repeated in patterns of fours, threes or twos, corresponding to 4/4, 3/4 and 2/4 times for musicians. Using fMRI scans to show active brain regions, Dr Katie Overy showed that groups of neurons deep inside the brain called the Basal Ganglia are very active when carrying out this task. The Basal Ganglia are highly connected regions that are really important in both sensory and motor processing, so this might be an interesting link between listening and moving to a beat. Not only this, but diseases involving the Basal Ganglia, such as Parkinson’s Disease, result in impaired beat detection. Perhaps by using music in more therapies we can provide better ways of treating Parkinson’s Disease and other Basal Ganglia disorders.

The emotional response to music
As most would agree, the soundtrack to a film deeply influences how a scene is portrayed. For instance, dissonant melodies convey discomfort and fear whereas smooth, major keys give a sense of calm and peace. At its most extreme, a piece of music can literally make our hairs stand up on end and give us the ‘chills’. This strong emotional response was measured by Dr Alan Watson of Cardiff University.

Dr Alan Watson’s lab used lie detectors to find out when we get the chills from a piece of music. This is due to the fact that lie detectors are very sensitive to changes in autonomic nervous system activity, such as sweating and pulse rate. Since our autonomic nervous system changes in response to strong emotions, the lie detector is a nifty way of showing when we get the chills! Using various imaging studies, the researchers were able to show that the chills are accompanied by a huge release of dopamine in the ‘pleasure’ circuits in the brain. This thus helps to explain why we can react so strongly to music.

Congenital Amusia and musicality
Some individuals are unable to enjoy music. Some, for example, even have trouble distinguishing between Happy Birthday and the National Anthem. These people may suffer from a condition called Congenital Amusia, a disorder of interpreting musical patterns. Yet, studies of these unique individuals may uncover just how innate musicality can be in the human brain. Dr Lauren Stewart from UCL collaborated with the BBC to carry out some of these studies.

Using a test called the Montreal Battery, the researchers found that people with this disorder have difficulty distinguishing musical tones compared with controls. They even have some trouble in detecting changes in speech tones, such as a question or a command. The research got more elaborate. The experimenters designed an artificial nonsense language and asked participants to detect if they heard a particular word in a phrase e.g. Pa-ti-ba. Interestingly, amusics were no different to controls, even when the ‘language‘ was replaced by musical tones! This indicates that amusia-sufferers may not have an absolute deficit in distinguishing pitches, but rather a lower confidence when doing so. This also indicates that a form of musicality is present in all individuals but can be honed by constant practice.

Dementia and music
Most of us are acquainted with someone who is going through the pain of dementia. It’s a very isolating ordeal for all involved and it’s expected to get much more common within the next few decades. Is music a good way of maintaining contact with sufferers who are gradually losing other precious memories?

Dr Jason Warren from UCL began by emphasising the complexity of music as a cognitive function. It’s encoded in many brain regions and evokes strong emotional and associative memories of events of that concert, party etc. All types of dementia have unique patterns of brain region damage. For example, Frontotemporal dementia (FTD) has specific damage in the knowledge-encoding temporal regions and the motor and emotion-encoding frontal regions of the brain. It turns out that FTD patients have selective impairments in identifying scary and angry music. This may prove to be an effective diagnostic tool because music is a much more robust memory than current tests using the memory of faces.

Peter Todd of the Alzheimer’s Society gave a fascinating talk about his experiences. He organises weekly singing groups called Singing for the Brain. The only difference here is that the participants are dementia sufferers at all stages of the disease. While it might not seem easy to pull off a group session with this requirement, the results of these groups are very encouraging. The groups have even performed at festivals and for BBC Radio 4! The aim of the groups is to include everyone at a personal level, no matter what level of dementia they are suffering. One heartwarming example of the good effects of these groups is of one patient who had lost his short-term memory. He couldn’t even remember that he had been in a singing group for the last hour! However, after every session, it was clear from his posture and manner that he was very upbeat from singing with the group, despite not being able to remember why! Examples like this emphasise the importance of music in social bonding for potentially lonely individuals going through dementia.

It’s clear that music has been an integral part of human history. This shown by the presence of music in every human culture on Earth and the sheer amount of processing power devoted to music in our brains. The brain is a pattern-seeking machine and it has progressed from interpreting primitive vocalisations in forests to sophisticated music forms. Our emotional connection to music and musicality is preserved to a certain extent in everyone. It also proves to be an effective tool for identifying dementia symptoms and also encourages social inclusion for dementia sufferers.

Oh, and if anyone was curious about how you turn a duck into a soul singer, the answer is: Put it in the microwave until its Bill Withers.

Friday, 6 December 2013

Catalytic Clothing: How Your Jeans Can Purify Air

by Emilie BergstrÓ§m

The UK frequently falls short of meeting EU air pollution emission targets, and it is estimated that air pollution is responsible for 50,000 deaths in the UK each year. Nitrogen oxides, NOx, and volatile organic compounds (VOCs), both produced in massive quantities from motor vehicles and industry, are two of the most prominent classes of pollutants. NOx are known to cause and worsen respiratory diseases, such as asthma and emphysema, and some VOCs are known carcinogens.

It has been known for some time that the harmful NOx and VOCs can be removed from the atmosphere via a catalytic conversion. Nanosized particles of titanium dioxide, TiO2, or nano-titania, are powerful photocatalysts that use sunlight and oxygen to speed up the oxidation of NOx into water soluble nitric acid that can be washed away with the rain, while also converting VOCs into fatty acids and soaps. 

Up until recently, nano-titania catalysts have only been placed on hard surfaces such as the walls of buildings. Helen Storey and Tony Ryan wanted to explore new applications of this technology. They contacted Cristal Global, the second largest supplier of nano-titania, to suggest collaborating on an initiative involving textiles. It was discovered that the efficacy of the catalyst when applied to textiles, particularly denim, was far higher than anticipated.

They have now partnered with the ecological cleaning brand, Ecover, to create a fabric softener able to deliver the photocatalyst to the surface of any piece of clothing during washing. The active agent is packaged within a shell that is attracted towards, and binds to, the surface of the clothing during the wash. Daily wear and washing create no problem for the catalyst particles, and they do not fall off until the cotton fibres of the jeans eventually break.

The key to catalysis, and increasing the rate of removal of NOx, is a high surface area. Nanoparticles have an extremely high ratio of surface area to volume and a pair of jeans has a surface area greater than 195 square feet. It has been estimated that if one person wears Catalytic Clothing for one day, they could remove the same amount of NOx as is produced by the average family in one day. 

A common misconception is that Catalytic Clothing will be a ‘dirt magnet’, putting people at greater risk of exposure to pollutants. This is not the case – the technology won't actively attract any pollutants, but will break down anything that comes within very close proximity of the catalyst's surface.

Wednesday, 4 December 2013

The KILLER whale

The Myriad of Killer Whale Hunting Techniques

by Rob Cooper

A titanic black shape emerges from the sea, huge leering white eyes aflame with malice rip through the sheet of water accompanying the streamlined monster as it emerges from the surf. Noticing its end far too late a seal barely has time to turn before it is grabbed by the neck and twisted voraciously around as the black and white menace of the deep, rather clumsily, makes its way back to the ocean.

Of course we are all well aware the killer whale or Orca is no monster but a simple animal, just as humans are. We’re also aware the large white areas on the flanks of the whale are not its eyes. However the immense range of prey and hunting practices employed by the mighty orca seems to have no compare outside of humans. Indeed the killer whale is one of the only animals in the world to be seen engaging in recreational hunting that can last for days in length (spending over 12 hours chasing and drowning a whale calf only leave all but the tongue and lower jaw uneaten) and has been recorded in several studies to have hunting success rates of nearly 100% on several prey types. This, it hardly needs clarification, is pretty much unmatched anywhere outside our own species.

How does the killer whale do this? What gives it an edge over predators such as sharks which are so well adapted they have remained almost completely unaltered over millions of years? And how do they manage to prey on so many different prey types with little morphological variation?

The answer is relatively simple: Intelligence

Killer whales have an enormous number of hunting strategies that are all applicable to different prey items which allow the different types to predate on a huge variety of marine fauna and avoid injury to themselves even with predating on creatures ten times their size.

Fish herding
Many groups of killer whales herd fish either into shallow water or to the surface by using the pod of whales to encircle and trap the fish. Norwegian killer whales take this a step further and use their tail flukes to stun vast swathes of fish which they can then pick of at their leisure. The combination of concentrated fish and the huge area of effect and stunning impact of the tail flukes means the whales can harvest huge amounts of fish with no need to spend energy chasing and catching individual fish. Some fish are completely pulverised by the huge tail fluke and end life merely as a bloody smear in the wake of their gargantuan predators.

Ice Floats
The only place your safe from killer whales is land right? Unfortunately this turns out to be wrong. Antarctic orcas have learnt to move in unison to create huge waves in the water that can wash seals and/or walrus from ice floats that they take refuge on. The whales actually break apart the ice floats using the movement of their own bodies to generate waves and proceed producing currents to move the floats to open water. This cuts off all avenues of escape and they then displace the seal from the ice with animal generated waves. By this point the seal is so exhausted from being repeatedly knocked of the ice float it has almost no energy to resist the whales attack and with deep water to emerge from the whales are comparatively safe from the seals jaws.

Killer whales targeting ice floats

The classic Orca hunt as mentioned in the first paragraph involves the emergence of the great animals onto land to catch a presumably very surprised and terrified seal: which is a decidedly risky strategy for such a large marine mammal that would crush its own organs under its body mass if it became trapped on the beach. The tactic however seems to work as adult killer whales can be seen nudging younger whales onto the beach in order to learn the trick for themselves. There remain few sights as awe inspiring and terror inducing as a six tonne wall of muscle emerging from the sea to capture its prey.

Orca beaching 

Shark Eaters
Many Killer whale groups have mastered the art of tackling sharks and stingrays through a lesser known phenomena entitled tonic immobility. The whales use their tail flukes or generate currents in order to flip the shark or ray onto its back. Once this has been achieved the shark or ray is completely paralysed whilst it remains on its back and the lethal sting of stingrays becomes inert. Killer whales finding great white sharks in their feeding grounds have been known to ram the shark at full speed and proceed to pull the creature to the surface and eat it alive. In this case the shark documented was a three meter long great white shark attacked by two killer whales who were feeding on the shark’s normal prey of sea lions near San Francisco.

Whale Hunting
Killer whales are second only to humans in their ruthless hunting of giant baleen whales. Antarctic killer whales have been described performing complex cooperative attacks on Bowhead whales with some whales immobilising the prey by attacking the flippers whilst others rammed the whale to cause internal damage such as broken ribs and finally the other whales swam on top of the Bowhead to cover the blowhole and force the Bowhead underwater to drown it. Antarctic killer whales are known to pursue the Finn whale to exhaustion in marathon 12 hour hunts with each whale taking its turn at the head of the pursuit. Killer whales have even been known to attack the giant sperm and blue whales with aggressive bull sperm whales and fully grown blue whales being pretty much the only animals safe from killer whale predation.