Research provides a window into the depressed mind – but could this really help to improve the view from the inside?

4241963210_f11f639bed_zThe science blogosphere has been awash this past week with articles exploring a link between depression and damage to part of the brain known as the hippocampus. News outlets, such as IFLS, are claiming that: “Depression Damages Parts of the Brain”. But, where does this assertion come from, is it really so cut and dry, and what impact will this research have on those currently living with major depression?

Firstly, as with many science news stories, the ideas discussed here are far from a new. What is new and exceptionally clever, is the way this study was performed:

As you might imagine, imaging the living brain is not an easy task and different researchers tackle this problem in different ways. This means that data analysis and imaging methods can vary a lot between research groups. Sadly, this lack of standardisation makes it hard to compare data across different studies, which limits the number of patients each study can look at. This is where this new work really shines. Through a massive international collaborative effort, this study has been able to standardise imaging protocols across a number of international labs. The study examines data from a whopping 1728 major depression patients and 7199 healthy controls, meaning that statistically these findings really pack a punch.

Their findings corroborate what other researchers already suspected – that recurrent depressive episodes seem to be accompanied by shrinking of a brain region known as the hippocampus. The hippocampus is best known for its role in memory formation, specifically in the conversion of new experiences to permanent long-term memories (think 50 First Dates or Memento). This region is arguably also integral to our sense of self. Without memories of our pasts how do we know who we are or what we want for the future? So, hippocampal damage could hold far reaching implications beyond that of simple memory loss and perhaps even contribute to many aspects of depression.

Now, the question scientists really want to answer is – what happens in the brain to cause depression? This study finds that hippocampal shrinkage is only significant in patents who have suffered from multiple depressive episodes, while patients who have only experienced a single episode have relatively normal hippocampi. This suggests that depression causes hippocampal shrinkage, rather than hippocampal shrinkage leading to depression.

Could this mean that we need to look beyond this brain region for the cause of depression?

Human hippocampus MRI in 3 different planes (marked by green cross)

Human hippocampus MRI in 3 different planes (marked by green cross)

It’s necessary to keep in mind that this work is not conclusive and may only represent part of a bigger picture. Large scale changes in the brain’s morphology, visible on MRI brain scans (as studied here), indicate significant cell loss. It is quite reasonable to assume that in the early stages of major depression, as with many long-term illnesses, changes in the body/brain may be more subtle – think alterations in brain chemistry and communication rather than large scale cell loss. So, although it’s useful to know that major depression can lead to hippocampal cell loss, we cannot yet rule this region out as a main player in the early stages of depression.

But, most importantly, will this research change anything for the >350 million people suffering from depression worldwide?

Well, actually this work feeds rather nicely into another hypothesis of depression known as ‘the neurotrophic hypothesis of depression’. In brief: It is known that stress and depression cause cell loss in limbic brain regions (including the hippocampus). Neurotrophic factors are proteins in the brain which encourage cell growth and multiplication, these are depleted in depressed patients and animal models of the disorder (often specifically within the hippocampus). Some scientists believe that a reduction in neurotrophins, such as BDNF (Brain Derived Neurotrophic Factor), begins a cascade which ultimately leads to cell damage and death. Therefore, it is possible that repeated episodes of major depression cause an additive loss of BDNF and perhaps subsequent hippocampal damage. Interestingly, a number of studies also suggest that antidepressants may increase BDNF in depressed patients, suggesting the effects of depression on the brain may be reversible.

So, it seems that when it comes to depression, scientists are slowly piecing together large parts of the puzzle. Although many uncertainties still exist (the brain is a tricky organ to understand), with continued research it is hoped that better treatments may be just around the corner.

Post by: Sarah Fox

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Why do mangos taste like pines?

4818759374_29e1e0a716_qHaving grown up in a South Eastern European country, where fruits are abundant and make up probably about half of our diet during the summer, I’m used to many different kinds of fruit. However, a banana was probably the most exotic fruit that I came across until the age of about sixteen.  So, I was pretty intrigued when a couple of months ago a friend of mine bought a mango for us to try. We googled ‘how to eat a mango’, cut it into those cute hedgehogs like they do and tasted it. But, since neither of us had ever tried this fruit before, we didn’t realise that it wasn’t ripe, so the taste was far from nice. Except for the part just around the pit it was like chewing on pine needles. Since then I have learned how to pick more or less ripe mangos and developed quite a taste for them but, I still can’t help noticing a hint of pine in the flavour. Every time this makes me ask myself, what is it that makes two plants that are so different in terms of their habitat and their taxonomic position taste or smell similar?

To get to the bottom of this lets start by looking at how the sense of taste operates and how it is linked to the sense of smell. The flavour of our food is determined by these two senses
combined: try holding your nose whilst eating, you’ll find even familiar foods don’t taste right. Our tongue, the roof, sides and the back of our mouth are covered with taste buds – small receptors sensitive to so called flavorants. The receptors that allow us to detect and recognise odors are somewhat similar to these taste receptors. The two systems rely on chemoreception, which means that the receptors involved are able to capture the chemical compounds that make up a certain smell or taste and transform this information into a nerve impulses in the brain. Information regarding both taste and smell combine in your brain allowing you to enjoy a multi-sensory flavour experience.

4402795295_013a780bbb_zNow back to the mango/pine problem. I decided to start my investigation by finding out what chemicals produce the familiar smell of pine. A quick trip to the nearest pharmacy and a scan through the ingredients of pine-scented essential oils revealed that the main components were: α-pinene, β-pinene, limonene, myrcene, camphene cadinene with very little variation from one brand to another. These compounds belong to a larger group known as terpenes, or more precisely monoterpenes, which are most commonly, but not exclusively, found in the resin of coniferous trees.

More than thirty different chemicals make up the flavour of mango and, surprisingly enough, α-pinene, β-pinene, limonene, myrcene and camphene are among them. So, five out of six compounds that are found in pine needles are also found in mango pulp.

Due to their strong smell, high viscosity and antiseptic properties, terpenes act as a repellent that drives away herbivores and insects, thus protecting the plant from predation. The native land for mangos is South and South East Asia and, while there are several varieties of pines that grow in the same part of the world, these plants are only distantly related. Pines are gymnosperms – even though they produce seeds, they develop neither a flower nor a fruit. Mangos on the other hand are flowering plants. From an evolutionary point of view they are considered to be more advanced than gymnosperms since they have flowers that facilitate pollination and their seed is protected by a fruit. Flowering plants diverged from gymnosperms more that 200 million years ago. So how did such different plants develop such a similar defense mechanism?

The first thing that pops to mind is convergent evolution. It is very common in nature for different animals which occupy very different habitats and never even come near each other to develop similar adaptations when faced with a similar obstacle. A classic example is the structure of an eye of vertebrates (e.g. mammals) and cephalopods (e.g. octopus): both these groups have independently developed camera eyes astonishingly similar in their structure and way of functioning. Therefore, an efficient system is very likely to develop in parallel across unrelated species.

So, in the case of pines and mangos, terpenes provide not only a reliable defense against predators but also a mind-bending taste anomaly.

Guest Post by: Daria Chirita.

unnamedOriginally from Moldova, I am currently in my second year at university in France, Université Jean Monnet , St Etienne, studying Biology. My scientific interests include Molecular Biology and Genetics, in which I am hoping to pursue a Master’s degree. Other than that I enjoy learning and speaking foreign languages, knitting and cinema.

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Keep your friends close – It may be good for your health

Screen Shot 2015-06-28 at 10.43.48We humans are social creatures. We love to meet up with our friends, family and partners, and rely on them for support through the good times and the bad. But it turns out we may also rely on our loved ones for our health. Our social ties may be helping us to keep sickness at bay and aiding a longer happier life.

There is no shortage of studies that suggest a potential link between feelings of social isolation and declining health in humans. In a study of 2,101 adults aged 50 years and over, a US-based group of scientists found that over a 6-year period, feelings of loneliness predicted higher rates of depression, a reduction in self-reported health and an increased risk of mortality. In 2010, an analysis of 148 separate studies showed that among the 300,000 plus participants, those with stronger social ties had an increased likelihood of survival.

So what is behind this link? Loneliness is well documented as a risk factor for co-morbidities such as increased blood pressure, obesity, lowered immune response, disrupted sleep, depression and cognitive decline in the elderly. But, is this simply due to the fact that negative feelings of loneliness lead us to take less care of ourselves, resulting in worse health? Or is there something more “biological” going on?

Although the precise biological mechanisms behind the impact of loneliness on our health remain unclear, there is a growing body of evidence to suggest this feeling may affect a Screen Shot 2015-06-28 at 10.43.57number of key systems in our bodies, including the hypothalamic-pituitary-adrenocortical (HPA) axis. The HPA axis is responsible for the release of important hormones called glucocorticoids – cortisol in humans and corticosterone in rodents. These hormones help regulate such things as our sleep, blood sugar, heart function and immune response. However, chronic high levels of glucocorticoids have also been linked with disease. Long-term increased levels of cortisol, for example, have been associated with high blood pressure, diabetes and an increased susceptibility to infection, as well as a number of other chronic diseases.

Interestingly, both urinary cortisol levels and HPA activation have been found to be increased in individuals who feel lonely, with higher levels of loneliness associated with greater cortisol increases. However, this effect only appears to be significant in individuals who are chronically lonely, suggesting the length of time one feels lonely for may play an important role in how this impacts upon our health.

Given the detrimental effect loneliness appears to have on our physical and mental well-being, one must wonder what the function of this feeling is? What is the benefit of making us feeling bad?

Screen Shot 2015-06-28 at 10.44.11From an evolutionary point of view, the aversive nature of loneliness is pretty logical. When we feel socially isolated or our social ties start to waver, we get the desire to reconnect with others. Back when we lived in tribes, maintaining social relationships allowed us to protect each other from predators and hunt more efficiently, thus ensuring the survival of our species. Similarly, our desire to find a mate allowed us to reproduce and ensure our genetic legacy. This is strengthened by an innate desire to care for our children as without a parent’s nurture and love, children would die.

In this respect, it also makes sense that we, as a species, are not alone in our social nature. Studies in social mammals, such as rats and rhesus monkeys, have found that social isolation of such animals can lead to anxious or depressive behaviour, altered physiology (e.g. blood pressure, inflammation, immune responses, etc.) and mortality. Social isolation has been shown to promote obesity and lead to type 2 diabetes in mice and even in the fruit fly, Drosophila melanogaster, isolation has been shown to reduce lifespan.

So, it seems loneliness may not just be an unpleasant feeling we all experience from time to time. Evidence suggests feelings of social isolation – particularly if these are chronic – could put us at risk of high blood pressure, diabetes and other health-related co-morbidities, not to mention possibly sending us to an early grave! Despite the negative feeling of loneliness coming with an evolutionary function – i.e. promoting the survival of the species – it certainly seems to be a feeling one may want to avoid. So pick up a phone and call your friends, reach out to your family and organise a meet up. Most importantly, keep those all important social ties strong – it may be good for your health!

Post by: Megan Barrett

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What can we learn from Tim hunt’s ‘problem with girls’: A female scientist’s opinion

Tim_Hunt_at_UCSF_05_2009_(4)Let me tell you about my trouble with girls … three things happen when they are in the lab … You fall in love with them, they fall in love with you and when you criticise them, they cry.” – This is the ill-conceived comment made recently by Nobel Laureate Sir Tim Hunt. A statement which spawned a spiral of media attention and ultimately lead to his forced resignation from position as Honorary Professor within the UCL Faculty of Life Sciences.

Crass, rude and culturally blind? Tim committed career suicide during his speech in a moment akin to watching a car crash in slow motion. Yes, anyone could have told Tim that this was not a smart move. But, why did an intelligent man who, on paper, doesn’t present as being your typical chauvinist pig make such insensitive comments and what can we learn from this?

From a brief background search, Tim is not someone I would have pegged as a chauvinist. He is married to Professor Mary Collins, a highly successful female scientist and an advocate for women in S.T.E.M subjects. Throughout his eminent career he has also worked with and mentored numerous female academics and has previously acknowledged their contribution to his Nobel winning discovery. Indeed, a number of his former female collaborators and confidants have recently spoken out in support of Tim’s character – including Manchester University’s own President and Vice-Chancellor Dame Nancy Rothwell.

A few years ago I also had the pleasure of meeting Tim with a small group of PhD students. To be honest, at the time I was stuck in an academic rut and felt like science just wasn’t my calling – volunteering for the discussion group with Tim was really just my elaborate way of escaping the lab for a few hours. However, I found the resulting discussion both stimulating and inspiring. Tim presented as a very ‘down to earth’ chap; he extolled the benefits of collaborations in science, acknowledged how hard discovery really is and encouraged us to nurture a healthy work-life balance. Although I certainly didn’t “fall in love with him”, I left with a positive impression of him both as a person and a scientist but, most importantly, I felt rejuvenated and ready to get back in the lab.

So, what happened? Why would a man surrounded by successful professional women make such a tasteless comment? And, was UCL’s response to the media storm that followed justified?

To answer these questions there are three important points we must first consider:

1) Context.

Twitter’s 140 character restriction is pretty limiting when it comes to contextualising statements. So, I’m happy to stand up and say that I don’t really have a clue how Tim’s remarks were delivered, or what his intention was at the time. But, one thing I’m beginning to realise is that reporting of both his intention and, in some cases, his actual words has been far from accurate. One of the most damning examples of this type of shoddy journalism is the observation that many mainstream media sources state that Tim admitted to being a chauvinist during his speech – a statement I believe to be misleading.

Whilst researching this article I listened to the original broadcast of BBC’s Today show discussing Tim’s comments and I was intrigued to hear conference attendee Connie St Louie state that “Tim stood up and said ‘I hope the women have prepared the lunch, I’m a male chauvinist pig”. Was this the comment these articles were referring to? If so, they were without doubt way off the mark in reporting his chauvinistic confession. To my ears this comment was undoubtedly said in jest. Indeed, if I were at the luncheon listening to his speech he certainly would have got a laugh from me! Further to this, I noted that, on the same show, Tim was introduced as “the scientist who said that women are for loving not for science” – if this isn’t a case of twisting his words to better fit their intended portrayal of his character I don’t know what is?

It seems to me that a whole storm of media attention and twitter hashtagging has spawned from a few lines presented without any real context. Personally, I’m waiting for someone to report Tim’s speech in its entirety since, until this happens, I can do little more than watch what’s going on from a comfortable position on the fence.

2)  Zeitgeist

Science is in a state of transition. Gone are the days of the ‘gentleman’ scientist, acting on instinct and funding research into whatever takes his fancy. With the introduction of government funding and charitable contributions, the scientific career path is open to many more people – and this is great. But, one striking observation is that, despite similar achievement and engagement early on in the education system, women still make up a shockingly low proportion of academic scientists (for facts and figures see here). A debate currently rages as to why so few women pursue the scientific career path, is it nature, nurture, or stern looks from the patriarchy? The jury is still out, but one thing is certain, it’s an emotive and very personal topic for many women.

Enter Tim. Speaking at a luncheon for women scientists and engineers Tim was entering a heated emotive atmosphere. Amongst the audience you would likely find a number of women who felt confident and comfortable combining their femininity with an academic career but, undoubtedly many others felt persecuted and let down by a male-driven field. Perhaps he was nervous, perhaps he’d had a little too much complimentary Champagne or perhaps he was used to being surrounded by happy, confident female academics who enjoy the occasional jibe…Whatever the case, Tim missed the mark by a mile and left many believing that he was part of the problem.

3) Reasonable punishment.

So, considering what we know about Tim and about what he said, where does this leave us?

A basic background check on Tim comes up clean, he seems like a pretty reasonable guy and a number of eminent female scientists are happy to defend his character. But, he did make some thoughtless comments, which he later defended – in his statement to the BBC he says “It’s terribly important that you can criticise people’s ideas without criticising them and if they burst into tears you tend to hold back from getting at the absolute truth. Science is about nothing but getting at the truth and anything that gets in the way of that, in my experience, diminishes the science”. This statement certainly makes his comments seem less jocular and lends credence to the idea that there may indeed be a kernel of truth behind his ‘jokes’. But, where should we go from here?

This is where the debate becomes heated. I personally believe that the punishment doled out to Tim does not fit the crime. Alongside a good track record of facilitating and working with female academics, Tim is also an outstanding scientist who, as a whole, seems to be spending his post-research years promoting the scientific career path (to both men and women). Stripping him of his position at UCL and, as a result, also of his other academic positions and making him ‘toxic’ to the industry does not seem appropriate. I’m certainly not suggesting that punishment isn’t necessary, only that we have taken this too far.

I also wonder if this backlash is side-stepping some important questions? Does Tim’s comment about women ‘crying’ highlight a viewpoint held by other academics? If so, is it then pertinent to use this as a springboard into discussions about managing researchers with different personality types and how to get the best out of all employees? Perhaps we can even use this as an opportunity to build a better understanding of existing prejudices in the field and work towards addressing these?

One thing is certain, Tim’s comments and his subsequent treatment have divided opinions both within and outside the academic community. Although I personally believe he has been treated too harshly, I know colleagues who think differently – In a recent Facebook debate, two of my fellow female colleagues had this to say:

I still think it’s sad that he didn’t offer a genuine apology before he ruined his and his wife’s career. Women today might think that they don’t have to be feminist because they have it all, but they have no idea how precarious our position is and how little sexism needs to become rampant again. Mysogyny is an aggressive weed with deep roots and it needs to be stamped on as soon as it raises its head, even as a joke. So I agree that unfortunately there was nothing else UCL could have done.” – Quote: Jadwiga Nazimek

He isn’t being demonized as sexist, he said a sexist thing, followed by a ‘sorrynotsorry’, and therefore has been rightly called sexist. It’s not fair to generalise his personal experience to all women, or in fact to all men, by implying these are female-specific behaviours, and that ‘girls’ are impossible to work with because of them.” – Quote: Sarah Ryan

We’d love to hear your opinions on the topic, so please add your voice to the debate in the comments section below.

Post by: Sarah Fox

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The dolphins that lend a helping flipper

Interactions between humans and animals can happen on many levels, but it is rare for the human to feel to be the less intelligent half of the relationship. Yet, when humans and dolphins meet, this can often seem to be the case. Generally, humans feel to be the master race, in control and superior to other animals. However, our encounters with dolphins can often demonstrate how they may operate on a level more similar to ours than we realise.

 The Common Dolphin. Photo Credit: NOAA NMFS via Wikimedia Commons

The Common Dolphin.
Photo Credit: NOAA NMFS via Wikimedia Commons

Some pods of wild dolphins have very interesting interactions with small fishing villages, especially in Brazil. Each morning the fishermen lay out their nets ready for the fish and each morning the local dolphin pod arrives and proceeds to herd fish towards the fishermen. If this behaviour wasn’t unusual enough, the dolphins have even begun signalling to the fishermen to tell them when to throw their nets using a system of fin slaps against the surface of the water. This coordination ensures the fishermen have full nets after a very short time.

This behaviour wasn’t trained or instructed by mankind; it is completely natural. But what do the dolphins gain? This is where it becomes a little less clear. Some speculate that they benefit by having an easy time of catching the fish that are trying to escape, but this isn’t known for sure.

 Painting of dolphins from the Bronze Age in Crete.  Photo Credit: H-stt via Wikipedia

Painting of dolphins from the Bronze Age in Crete.
Photo Credit: H-stt via Wikipedia

All that is known is that this strange working relationship is a natural occurrence that will continue on. The fishermen will teach their sons to watch for the dolphins’ signals, and the dolphins will teach their calves to herd the fish.

When humans enter the sea we are, in a sense, invading the dolphins’ home. Yet, even when we place ourselves outside of our natural habitat and get into difficulty, instead of ignoring us or despising us for intruding on their world dolphins are well known for lending a flipper. Stories can be traced back to Ancient Greek legends of dolphins rescuing sailors. This isn’t just a myth though – more recent stories of dolphins staying with lost divers can be found from all around the world.

Here is an instance where the dolphins aren’t just interacting with humans freely but where they are also going out of their way to help us when we’re in distress. They have been witnessed attacking sharks that are threatening people in the water. But, again, why? Why are dolphins choosing to do this? They could be the first animal that has ever shown true altruism (besides humans).

Photo Credit: Claudia14 via Pixabay. Image used under Creative Commons Deed CC0

Photo Credit: Claudia14 via Pixabay. Image used under Creative Commons Deed CC0

The dolphins could drive fish into nets to gain an easy meal, but protecting humans doesn’t show a clear benefit for them. All other animals allow the ecosystem to flow as normal and will not interfere with its course. In these two examples, however, the dolphins have chosen not just to intervene but to intervene to help one species at the expense of another. They drive fish to their deaths so that we may catch them. They stop the sharks from having an easy meal to save the lives of humans.

We speculate about the degree of intelligence dolphins possess and it is well recognised that they are intelligent creatures; so perhaps they are intelligent enough to understand us better than we think. Perhaps, similarly to humans, there are both good and bad dolphins. We hear of dolphins rescuing people only from those that were rescued; we don’t hear about the people that drown because a pod of dolphins ignored them. Some speculate that they are acting more from choice rather than instinct, which would mean they have a higher level of awareness than we first realised.

Unless we can decipher the dolphins’ communication techniques, something we have been trying to do since the 1960’s, we may never know why these magnificent beings occasionally go out of their way to help us.

This post, by author Jennifer Rasal, was kindly donated by the Scouse Science Alliance and the original text can be found here.

References
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Room to breath

Recently, the UK Supreme Court ruled that the government must take immediate action to cut air pollution, ordering “that the Government must prepare and consult on new air quality plans for submission to the European Commission… no later than December 31 2015”. This was brought about when the UK was found to be in breach of its duty to achieve legally binding limits for nitrogen dioxide by an initial 2010 deadline. So what exactly is nitrogen dioxide, where does it come from, and why is it so bad for us?

Nitrogen dioxide, or NO2, is a molecule consisting of one nitrogen atom and two oxygen atoms. It is produced via the oxidation of nitric oxide (NO) in air – natural sources include; lightning, plants, soil and water. However, overall, only about 1% of the total amount of nitrogen dioxide found in urban environments comes from these natural processes. In urban areas, about 80% of atmospheric NO2 comes from motor vehicle exhausts with smaller amounts arising from other sources, include metal refining, and electricity generation from coal-fired power stations.

Lightning is a (small) natural source of nitrogen dioxide (Photo Credit: Diegojaf22 via Wikimedia Commons).

Lightning is a (small) natural source of nitrogen dioxide (Photo Credit: Diegojaf22 via Wikimedia Commons).

Nitrogen dioxide reacts with moisture, ammonia, and other compounds to form small particles. Inhaling nitrogen dioxide can be extremely harmful to humans, because these particles penetrate deeply into the body, damaging the lining of the lungs through abrasion. This can act to reduce immunity to lung infections, and cause problems such as wheezing, coughing, flu and bronchitis. Increased levels of nitrogen dioxide have even more significant impacts on people with asthma leading to fiercer, and more frequent attacks. However, the impacts of air pollution goes beyond asthma and other respiratory diseases, having been linked to heart attacks and strokes; the world health organisation has also formally classified outdoor air pollution as a carcinogen, causing both lung and bladder cancers.

Traffic in not just bad for our stress levels (Photo Credit: Stephen via Wikimedia Commons).

Traffic in not just bad for our stress levels (Photo Credit: Stephen via Wikimedia Commons).

Current figures place the number of deaths caused by air pollution in the UK somewhere between 29,000 and 30,000 a year – which is more than the number of deaths resulting from obesity and alcohol combined. Even more worryingly, a recent study found that these statistics do not factor in nitrogen dioxide, and only include deaths caused by particulate matter (i.e. particles suspended in the Earth’s atmosphere). The Committee on the Medical Effects of Air Pollutants is due to publish its findings later this year, where it is predicts that the premature death toll caused by road traffic pollution will be around twice as high as originally thought.

According to DEFRA the average roadside concentrations of nitrogen dioxide had fallen 15% since 2010.  In addition both nitrogen dioxide emissions and background concentrations had more than halved in the 20 years since the mid 90s. However, whilst nitrogen dioxide emissions from petrol cars have fallen significantly over past 20 years, the emissions from diesel cars have overall shown little change during the same period.

Greater Manchester residents can find out more about the air quality in their local area at the GreatAir Manchester website, which provides daily pollution indices, as well as host of useful resources and advice. The DEFRA air quality website is also a great resource, and provides daily pollution notifications, as well as five-day pollution forecasts. If you have any respiratory problems and are planning on being outside for a long time, then it is well worth checking these websites first, especially if you plan on doing any vigorous activities.

The DEFRA air quality index id based on measurements made by measurement stations like this one in Edinburgh (Photo Credit: David Monniaux via Wikimedia Commons).

The DEFRA air quality index id based on measurements made by measurement stations like this one in Edinburgh (Photo Credit: David Monniaux via Wikimedia Commons).

It is important to remember however, that this is not simply a straightforward problem. For example, because of the complex nature of the chemistry that is involved, a decrease in nitrogen dioxide levels can actually lead to an increase in surface level ozone, which is also a harmful pollutant, and which in Europe alone is responsible for approximately 20,000 premature deaths a year. You can read more about the relationship between ozone and nitrogen dioxide in this paper.

The Supreme Court’s ruling could be a watershed moment in the UK’s fight to improve air pollution in our urban areas, and with UN statistics showing that over 80 % of the UK’s population is currently living in urban environments, it is important that we act now, before it is too late.

Post by: Sam Illingworth

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Hearing voices: more common than you might think

I remember being woken up from one of my daily naps by the familiar melody of the ice cream van that comes round our estate every day in summer. True, it was slightly odd that I could hear it so vividly despite wearing ear plugs; nevertheless I leaped out of bed, grabbed my purse and ran outside. Imagine my disappointment when I realized that there was no ice cream van in sight!

Voices can be loud and clear, or barely distinguishable from thoughts.  Image courtesy of stockimages at FreeDigitalPhotos.net

Voices can be loud and clear, or barely distinguishable from thoughts.
Image courtesy of stockimages at FreeDigitalPhotos.net

Auditory hallucinations are more common that we might think, and they do not only happen to people with mental health problems. The example I described above is a form of hypnopompic hallucinations, i.e. those experienced upon awakening from sleep, and familiar to just over 12% of the population (Ohayon et al., 1996).

Let’s take a moment though to consider what we mean by a ‘hallucination’. The word itself comes from the Latin ‘allucinari’ meaning ‘to wander in the mind’, ‘to dream’ (Choong et al., 2007). It is a perception that occurs in the absence of an external stimulus, when we are fully or partially awake, and is not to be confused with an illusion, which is a misperception of a real stimulus. Hallucinations are one of the cardinal symptoms of schizophrenia; indeed, 70% of people with this illness hear voices. However, they are not the only ones. In some studies 10% of men and 15% of women in the general population described hearing voices at some point in their lives (Tien, 1991). It is not uncommon to experience hallucinations when we are drifting off to sleep (hypnagogic) or  when we are waking up (hypnopompic). Hearing voices might affect us even more after we lose a loved one; nearly half of recent widows and widowers hear the voice of their dead spouse (Carlsson and Nilsson, 2007).

What is it then that people hear? Hallucinations could be fragments of memories or stream of consciousness, often related to worries, and are more likely to occur in times of stress or tiredness.  The voices could be loud and clear, as if someone in the room has just spoken, or they could be barely distinguishable from our thoughts.

“I hear a mixture of men and women, but no children. They usually tell me to do things, but not dangerous things. Like they’ll tell me to take out the garbage or check the lock on the window or call someone. Sometimes they comment on what I’m doing and whether I’m doing a good job or what I could be doing better.” (Woods et al., 2015).

Since hallucinations affecting healthy people have a similar form to those that torment patients with schizophrenia, scientists think that they are on the continuum of normal perception. Where, then, is the line between ‘normal’ and ‘psychotic’ hallucinations and if we hear voices, does it mean we are at risk of a mental illness? Hallucinations that lead to, or are part of a disorder tend to be more negative and intrusive, and are associated with more anxiety and depression. For example, a healthy person might find spiritual or religious explanation for their voices and is more likely to ‘go along’ with them, whereas a person with psychosis is more likely to think that the voice belongs to a real person and try to resist it. The distress that the voices can cause might create a vicious cycle, where the more the individual fears and tries to avoid the voices, the more intrusive and frightening they become.

Voices in mental illness tend to be more negative and associated with more depression.  Image courtesy of David Castillo Dominici at FreeDigitalPhotos.net

Voices in mental illness tend to be more negative and associated with more depression.
Image courtesy of David Castillo Dominici at FreeDigitalPhotos.net

“Starting when I was about 20 years old, I heard the voices of demons screaming at me, telling me that I was damned, that God hated me, and that I was going to hell… The voices were so frightening and disruptive that much of the time I was unable to focus or concentrate on anything else.”

The physiological underpinnings of hallucinations are not clear. We know that hearing sounds and voices that are not there activates the auditory cortex in a similar way  to ‘real’ auditory stimuli. The content of hallucinations are probably best understood in the context of the individual’s life, personality and experiences. A simple melody produced by the auditory cortex in response to your craving for ice cream is harmless enough. Similarly, hearing the voice of a dead loved one might be comforting; their voice is imprinted on your brain – no wonder it can be reproduced when you long to hear it. Perhaps the derisive commentary is your internal critic that harnessed the auditory cortex to torment you? One thing is certain: whilst voices can be very distressing and coping with them often requires professional help, they are not always dangerous or a sign of mental illness.

Post by: Jadwiga Nazimek

References:

Carlsson, M. E. & Nilsson, I. M. (2007) Bereaved spouses’ adjustment after the patients’ death in palliative care. Palliative and Supportive Care, 5, 397-404.

Choong, C., Hunter, M. D. & Woodruff, P. W. (2007) Auditory hallucinations in those populations that do not suffer from schizophrenia. Current Psychiatry Reports, 9, 206-12.

Johns, L., Kompus, K., Connell, M. et al. (2014) Auditory Verbal Hallucinations in Persons With and Without a Need for Care. Schizophrenia Bulletin 40 (4): 255-264

http://schizophreniabulletin.oxfordjournals.org/content/40/Suppl_4/S255.full

Nayani, T. H. & David, A. S. (1996) The Auditory Hallucination: a Phenomenological Survey. Psychological Medicine, 26, 179-192.

Ohayon, M. M., Priest, R. G., Caulet, M. & Guilleminault, C. (1996) Hypnagogic and hypnopompic hallucinations: pathological phenomena? British Journal of Psychiatry, 169, 459-67.

Tien, A. Y. (1991) Distributions of hallucinations in the population. Social Psychiatry and Psychiatric Epidemiology, 26, 287-92.

Woods, A., Jones, N., Alderson-Day, B., Callard, F., fernyhough, C. (2015) Experiences of         hearing voices: analysis of a novel phenomenological survey. The Lancet. Psychiatry http://www.thelancet.com/journals/lanpsy/article/PIIS2215-0366%2815%2900006-1/fulltext

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