Research Digest post #2

My time in the BPS Research Digest hotseat continues. Today’s post is about a lovely study by Stuart Ritchie and colleagues which uses a unique dataset to look at the effect of alcohol on cognitive function across the lifespan. Here’s the intro:

The cognitive cost or benefit of booze depends on your genes, suggests a new study which uses a unique longitudinal data set.

Inside the laboratory psychologists use a control group to isolate the effects of specific variables. But many important real world problems can’t be captured in the lab. Ageing is a good example: if we want to know what predicts a healthy old age, running experiments is difficult, even if only for the reason that they take a lifetime to get the results. Questions about potentially harmful substances are another good example: if we suspect something may be harmful we can hardly give it to half of a group of volunteer participants. The question of the long-term effects of alcohol consumption on cognitive ability combines both of these difficulties.

You can read the rest here: Alcohol could have cognitive benefits – depending on your genes.

See also, Tuesday’s post: A self-fulfilling fallacy?

Detecting inner consciousness

CC Licensed photo by Flickr user hernán. Click for source.Mosaic has an excellent in-depth article on researchers who are trying to detect signs of consciousness in patients who have fallen into coma-like states.

The piece meshes the work of neuroscientists Adrian Owen, Nicholas Schiff and Steven Laureys who are independently looking at how to detect signs of consciousness in unresponsive brain-injured patients.

It’s an excellent piece and communicates the key difference between various states of poor response after brain injury that are crucial for making sense of the ‘consciousness in coma’ headlines.

One of the key concepts is the minimally conscious state which is where patients show signs of fleeting and impaired consciousness but which is nonetheless verifiably present.

However, MCS is still a very impaired state to be in and this is sometimes missed by news reports.

For example, lots of coverage of a recent Lancet study suggested that ‘one third of patients in persistent vegetative state (a state with no reliable signs of consciousness) may be conscious’ as if this meant they were fully conscious but trapped in their bodies, when actually they just reached criteria for minimally conscious state.

My only point of contention with the Mosaic article is that it’s a little too enthusiastic about sleeping pill zolpidem, which has been reported to lead to a ‘miraculous’ recovery in some case reports but where results from early systematic studies still look bleak.

Nevertheless, an excellent piece that’s probably one of the best accounts of this important and innovative area of research you’re likely to read for a long-time.
 

Link to Mosaic article ‘The Mind Readers’.

Coma alarm dreams

Intensive Care Medicine has published a wonderfully written and vivid account from a teenager who spent time brain injured and hallucinating in an intensive care unit.

The writer describes how he was admitted to intensive care at the age of 15 after suffering a head injury and had intense and bizarre hallucinations which are, as we know now, surprisingly common in critical care patients.

My experience of the time under sedation can be split into two. There was what I could perceive of the real world around me, and then there was my dream world.

In the real world, the most constant feature was sound. I could hear the nurses talking, understanding everything they said. They always spoke their names. They were always kind, conscious I think that I might hear them. They helped me to relax. I could hear the noises of the ward, tones of voices and alarms. The alarms made me tense. I can remember Mum talking to me a lot and Dad reading me ‘The Hobbit’, although I still can’t remember the names of all the dwarves. Mum and Dad’s voices always came from the left.

My other senses were not wholly switched off either. Things were put in my mouth: tubes, sucky things, wet watery pads and a toothbrush. Someone moved my hair about. I felt furry and silky toys placed under my fingers. My brother and sisters had brought a knitted tortoise and a horse for me. My feet were moved about and stretched, which felt really good. I remember that the rolled-up bed sheets were uncomfortable.

Other sensations were less good. The constant, repetitive shining of a bright light in my remaining eye really annoyed me – I am sure I can remember every single time.

Then there was my dreaming. I lived in the dream world nearly all the time and it went on and on. The dreams were vivid, terrifying and very disturbing. There were some good ones but unfortunately for me a lot of really bad ones. I can still remember most of them even now, more than a year since.

At the sound of an alarm, a giant monster appeared with a meat cleaver and pursued me around the sports hall. I had to protect a girl and prevent an army from crossing a river. The whole river and hall were aflame. I was burning from the heat.

In another I had to stop an alarm-driven colossal centipede from crossing a bridge. I could see the shadow of monsters looming towards me behind a curtain. I knew the monsters were there and about to consume me, but I lay transfixed, unable to move, and I remember feeling myself sweating with excruciating fear. I was then on the bridge of a nuclear submarine with maniacs trying to blow up the world, there was a huge explosion. Then it ended.

I was aboard a flying craft. I was there to stop green-coated aliens from creating human missiles. The aliens were forcing people into missile tubes. They were going to drop the human bombs from the aircraft.

Then there was a shape-shifter leopard beast chasing me and my friends. We were working in a fast-food place on a ship. It cornered us, and the Kentucky Fried Chicken sign burst into red lightning.

But I knew when something really nasty was going to happen. I could always hear the same alarm going off. It was a signal for the monsters to appear, for the centipede to attack, for bombs to be dropped, I would be sacrificed…I was very afraid. Tension would build to some hideous climax. Looking back, I suspect the pressure in my brain was causing both the nightmares and the alarm to go off.

I have made a great recovery from my injuries due in large part to the excellent care that was taken of my brain in intensive care. I have been into see the team a few times but I never stay too long. Those alarms still make me feel nervous!

As I noted in a recent article, these sorts of hallucinations were thought to be a distressing but ultimately irrelevant part of recovery but more recent studies suggests that have longer-term psychological impact that can be problematic in its own right.
 

Link to locked article ‘Coma alarm dreams on paediatric intensive care’

Bomb disposal for the brain

New Statesman has an excellent profile of the wise, funny and acerbic neurosurgeon Henry Marsh.

Marsh was the subject of the fantastic 2007 documentary The English Surgeon but he’s now one year away from retirement and has clearly decided that diplomatic responses are no longer a tactical necessity.

The piece also gives a vivid insight into the working life and daily challenges of a consultant neurosurgeon.

It’s also wonderfully written. This is pure joy:

When he finally went to medical school, at the Royal Free Hospital in London, he wasn’t sure about his choice. “I thought medicine was very boring,” he says bluntly. Henry is not a man to refrain from speaking his mind. “I didn’t like doctors. I didn’t like surgeons. It all seemed a bit dumb to me.” In Do No Harm he writes of his revulsion at what much surgery generally entails: “long bloody incisions and the handling of large and slippery body parts”.

But while working as a senior house officer, he observed a neurosurgeon use an operating microscope to clip off an aneurysm – a small, balloon-like blowout on the cerebral arteries that can cause catastrophic haemorrhages. It is intensely delicate work, using microscopic instruments to manipulate blood vessels just a few millimetres in diameter. It is also, as Henry says, like bomb disposal work, in that it can go very badly wrong – with the crucial difference that it is only the patient’s life at risk, not the surgeon’s. If this or any other kind of serious neurosurgery goes right, however, the doctor is a hero. “Neurosurgery,” he smiles, “appealed to my sense of glory and self-importance.”

Marsh has just written an autobiography called Do No Harm which I’ve just started reading. I’m only part way through but it’s already gripping and wonderfully indiscreet.
 

Link to New Statesman profile of Henry Marsh.

A balanced look at brain scanning

Bioethics think tank The Hastings Center have published an excellent open-access report on ‘Interpreting Neuroimages: The Technology and its Limits’ that takes a critical but balanced look at the use of brain scans for understanding the mind.

They’ve commissioned leading cognitive neuroscientists to write chapters including Geoffrey Aguirre, Martha Farah and Helen Mayberg, as well as having a chapter by some legal folks who discuss whether neuroimaging can teach us anything about moral and legal responsibility.

The chapter by the brilliant Martha Farah is particularly good and takes a level-headed look at the critiques of fMRI and is essential reading if you want to get up to speed on what brain scans are likely to tell us about the mind and brain.

The report is all in academic writing but if you’re a dedicated neuroscience fan, it probably won’t pose too much of a problem.

 

Link to ‘Interpreting Neuroimages: The Technology and its Limits’.

Frozen nightmares

The Devil in the Room is a fantastic short film about the experience of hallucinatory sleep paralysis – a common experience that has been widely mythologised around the world.

Sleep paralysis is the experience of being unable to move during the process of waking – when you have regained consciousness but you’re brain has not re-engaged your ability to control your muscles.

The reason the experience has been widely associated with mythological creatures is because in some people it can lead to intense emotions and hallucinations.

The name ‘sleep paralysis’ is a bit confusing because this also refers to normal sleep paralysis – where your brain disengages control of your muscles during REM sleep to stop you ‘acting out’ your dreams.

The film is part of the Sleep Paralysis Project, which has much more about the experience on their website.
 

Link to ‘Devil in the Room’ on vimeo.

Loving you is easy because you’re beautiful

Neuroscape Lab, we salute your next generation of brain visualisation, that looks like something out of a sci-fi film where the director is a bit obsessed with correctly representing the anatomy of the brain.

They describe the visualisation like this:

This is an anatomically-realistic 3D brain visualization depicting real-time source-localized activity (power and “effective” connectivity) from EEG (electroencephalographic) signals. Each color represents source power and connectivity in a different frequency band (theta, alpha, beta, gamma) and the golden lines are white matter anatomical fiber tracts. Estimated information transfer between brain regions is visualized as pulses of light flowing along the fiber tracts connecting the regions.

But honestly, who cares? It’s a glowing rotating brain with golden streaks of light flowing through it.

In fact, after 25 years, science has finally scanned the brain from The Orb’s ambient techno classic ‘A Huge Ever Growing Pulsating Brain That Rules from the Centre of the Ultraworld’.

It’s as if the rave generation stumbled out of life’s warehouse at 7am and ended up being neuroscientists.
 

Link to Neuroscape Lab’s awesome brain visualisation.
Link to the original Orb track (or the classic Orbital remix)