Posts tagged consciousness
Articles and news from the latest research reports.
To recover consciousness, brain activity passes through newly detected states
Anesthesia makes otherwise painful procedures possible by derailing a conscious brain, rendering it incapable of sensing or responding to a surgeon’s knife. But little research exists on what happens when the drugs wear off.
(Image caption: Unconscious states. New findings suggest the anesthetized brain must pass through certain ‘way stations’ on the path back to consciousness. Above, the prevalence of particular clusters of brain activity states as recorded in rats that had been administered an anesthetic. The longest appear in red and the shortest in yellow and green.)
“I always found it remarkable that someone can recover from anesthesia, not only that you blink your eyes and can walk around, but you return to being yourself. So if you learned how to do something on Sunday and on Monday, you have surgery, and you wake up and you still know how to do it,” says Alexander Proekt, a visiting fellow in Don Pfaff’s Laboratory of Neurobiology and Behavior at Rockefeller University and an anesthesiologist at Weill Cornell Medical College. “It seemed like there ought to be some kind of guide or path for the system to follow.”
The obvious explanation is that as the anesthetic washes out of the body, electrical activity in the brain gradually returns to its conscious patterns. However, new research by Proekt and colleagues suggests the trip back is not so simple.
“Using statistical analysis, our research shows that the recovery from deep anesthesia is not a smooth, linear process. Instead, there are dynamic ‘way stations’ or states of activity the brain must temporarily occupy on the way to full recovery,” Pfaff says. “These results have implications for understanding how someone’s ability to recover consciousness can be disrupted by, for example, brain injury.”
Proekt, along with former postdoc Andrew Hudson, now an assistant professor in anesthesiology at the University of California, Los Angeles, and Diany Paola Calderon, a research associate in the lab, put rats “under” using the common medical and veterinary anesthetic isoflurane. As the rats recovered, the team monitored the electrical potential outside neurons, known as local field potentials (LFPs), in particular parts of the brain known, from previous elecrophysiological and pharmacological studies, to be associated with wakefulness and anesthesia. These recordings gave them a sensitive handle on the activities of whole groups of neurons in particular parts of the thalamus and cortex.
In the awake brain, of both humans and rats, neurons generate electrical voltage that oscillates. Many of these oscillations together form a signal that appears as a squiggly line on a recording of brain activity, such as an LFP. When someone is asleep, under anesthesia, or in a coma, these oscillations occur more slowly, or at a low frequency. When he or she is awake, they speed up. The researchers examined the recordings from the rats’ brains to figure out how the electrical activity in these regions changed as they moved from anesthetized to awake.
“Recordings from each animal wound up having particular features that spontaneously appeared, suggesting their brain activity was abruptly transitioning through particular states,” Hudson says. “We analyzed the probability of a brain jumping from one state to another, and we found that certain states act as hubs through which the brain must pass to continue on its way to consciousness.” While the electrical activity in all the rats’ brains passed through these hubs, the precise path back to consciousness was not the same each time, the team reports today in the Proceedings of the National Academy of Sciences.
“These results suggest there is indeed an intrinsic way in which the unconscious brain finds its way back to consciousness. The anesthetic is just a tool for severely reducing brain activity in a way in which we can control,” Hudson says.
In other scenarios, including coma caused by brain injury or neurological disease, the disruption to brain activity cannot be controlled, making these states much more difficult to study. However, the team’s results may help explain what is going on in these cases. “Maybe a pathway has shut down, or a brain structure that was key for full consciousness is no longer working. We don’t know yet, but our results suggest the possibility that under certain circumstances, someone may be theoretically capable of returning to consciousness but, due to the inability to transition through the hubs we have identified, his or her brain is unable to navigate the way back,” Calderon says.
(Source: newswire.rockefeller.edu)
Losing the left side of the world: Rightward shift in human spatial attention with sleep onset
Unilateral brain damage can lead to a striking deficit in awareness of stimuli on one side of space called Spatial Neglect. Patient studies show that neglect of the left is markedly more persistent than of the right and that its severity increases under states of low alertness. There have been suggestions that this alertness-spatial awareness link may be detectable in the general population. Here, healthy human volunteers performed an auditory spatial localisation task whilst transitioning in and out of sleep. We show, using independent electroencephalographic measures, that normal drowsiness is linked with a remarkable unidirectional tendency to mislocate left-sided stimuli to the right. The effect may form a useful healthy model of neglect and help in understanding why leftward inattention is disproportionately persistent after brain injury. The results also cast light on marked changes in conscious experience before full sleep onset.
(Image: ALAMY)
The claustrum’s proposed role in consciousness is supported by the effect and target localization of Salvia divinorum
This article brings together three findings and ideas relevant for the understanding of human consciousness: (I) Crick’s and Koch’s theory that the claustrum is a “conductor of consciousness” crucial for subjective conscious experience. (II) Subjective reports of the consciousness-altering effects the plant Salvia divinorum, whose primary active ingredient is salvinorin A, a κ-opioid receptor agonist. (III) The high density of κ-opioid receptors in the claustrum. Fact III suggests that the consciousness-altering effects of S. divinorum/salvinorin A (II) are due to a κ-opioid receptor mediated inhibition of primarily the claustrum and, additionally, the deep layers of the cortex, mainly in prefrontal areas. Consistent with Crick and Koch’s theory that the claustrum plays a key role in consciousness (I), the subjective effects of S. divinorum indicate that salvia disrupts certain facets of consciousness much more than the largely serotonergic hallucinogen lysergic acid diethylamide (LSD). Based on this data and on the relevant literature, we suggest that the claustrum does indeed serve as a conductor for certain aspects of higher-order integration of brain activity, while integration of auditory and visual signals relies more on coordination by other areas including parietal cortex and the pulvinar.
From the Phenomenology to the Mechanisms of Consciousness: Integrated Information Theory 3.0
This paper presents Integrated Information Theory (IIT) of consciousness 3.0, which incorporates several advances over previous formulations. IIT starts from phenomenological axioms: information says that each experience is specific – it is what it is by how it differs from alternative experiences; integration says that it is unified – irreducible to non-interdependent components; exclusion says that it has unique borders and a particular spatio-temporal grain. These axioms are formalized into postulates that prescribe how physical mechanisms, such as neurons or logic gates, must be configured to generate experience (phenomenology). The postulates are used to define intrinsic information as “differences that make a difference” within a system, and integrated information as information specified by a whole that cannot be reduced to that specified by its parts. By applying the postulates both at the level of individual mechanisms and at the level of systems of mechanisms, IIT arrives at an identity: an experience is a maximally irreducible conceptual structure (MICS, a constellation of concepts in qualia space), and the set of elements that generates it constitutes a complex. According to IIT, a MICS specifies the quality of an experience and integrated information ΦMax its quantity. From the theory follow several results, including: a system of mechanisms may condense into a major complex and non-overlapping minor complexes; the concepts that specify the quality of an experience are always about the complex itself and relate only indirectly to the external environment; anatomical connectivity influences complexes and associated MICS; a complex can generate a MICS even if its elements are inactive; simple systems can be minimally conscious; complicated systems can be unconscious; there can be true “zombies” – unconscious feed-forward systems that are functionally equivalent to conscious complexes.
Human consciousness is simply a state of matter, like a solid or liquid – but quantum
Thanks to the work of a small group neuroscientists and theoretical physicists over the last few years, we may finally have found a way of analyzing the mysterious, metaphysical realm of consciousness in a scientific manner. The latest breakthrough in this new field, published by Max Tegmark of MIT, postulates that consciousness is actually a state of matter. “Just as there are many types of liquids, there are many types of consciousness,” he says. With this new model, Tegmark says that consciousness can be described in terms of quantum mechanics and information theory, allowing us to scientifically tackle murky topics such as self awareness, and why we perceive the world in classical three-dimensional terms, rather than the infinite number of objective realities offered up by the many-worlds interpretation of quantum mechanics.
![Functional brain imaging reliably predicts which vegetative patients have potential to recover consciousness
A functional brain imaging technique known as positron emission tomography (PET) is a promising tool for determining which severely brain damaged individuals in vegetative states have the potential to recover consciousness, according to new research published in The Lancet.
It is the first time that researchers have tested the diagnostic accuracy of functional brain imaging techniques in clinical practice.
“Our findings suggest that PET imaging can reveal cognitive processes that aren’t visible through traditional bedside tests, and could substantially complement standard behavioural assessments to identify unresponsive or “vegetative” patients who have the potential for long-term recovery”, says study leader Professor Steven Laureys from the University of Liége in Belgium.
In severely brain-damaged individuals, judging the level of consciousness has proved challenging. Traditionally, bedside clinical examinations have been used to decide whether patients are in a minimally conscious state (MCS), in which there is some evidence of awareness and response to stimuli, or are in a vegetative state (VS) also known as unresponsive wakefulness syndrome, where there is neither, and the chance of recovery is much lower. But up to 40% of patients are misdiagnosed using these examinations.
“In patients with substantial cerebral oedema [swelling of the brain], prediction of outcome on the basis of standard clinical examination and structural brain imaging is probably little better than flipping a coin,” writes Jamie Sleigh from the University of Auckland, New Zealand, and Catherine Warnaby from the University of Oxford, UK, in a linked Comment.
The study assessed whether two new functional brain imaging techniques—PET with the imaging agent fluorodeoxyglucose (FDG) and functional MRI (fMRI) during mental imagery tasks—could distinguish between vegetative and MCS in 126 patients with severe brain injury (81 in a MCS, 41 in a VS, and four with locked-in syndrome—a behaviourally unresponsive but conscious control group) referred to the University Hospital of Liége, in Belgium, from across Europe. The researchers then compared their results with the well-established standardised Coma Recovery Scale–Revised (CSR-R) behavioural test, considered the most validated and sensitive method for discriminating very low awareness.
Overall, FDG-PET was better than fMRI in distinguishing conscious from unconscious patients. Mental imagery fMRI was less sensitive at diagnosis of a MCS than FDG-PET (45% vs 93%), and had less agreement with behavioural CRS-R scores than FDG-PET (63% vs 85%). FDG-PET was about 74% accurate in predicting the extent of recovery within the next year, compared with 56% for fMRI.
Importantly, a third of the 36 patients diagnosed as behaviourally unresponsive on the CSR-R test who were scanned with FDG-PET showed brain activity consistent with the presence of some consciousness. Nine patients in this group subsequently recovered a reasonable level of consciousness.
According to Professor Laureys, “We confirm that a small but substantial proportion of behaviourally unresponsive patients retain brain activity compatible with awareness. Repeated testing with the CRS–R complemented with a cerebral FDG-PET examination provides a simple and reliable diagnostic tool with high sensitivity towards unresponsive but aware patients. fMRI during mental tasks might complement the assessment with information about preserved cognitive capability, but should not be the main or sole diagnostic imaging method.”
The authors point out that the study was done in a specialist unit focusing on the diagnostic neuroimaging of disorders of consciousness and therefore roll out might be more challenging in less specialist units.
Commenting on the study Jamie Sleigh and Catherine Warnaby add, “From these data, it would be hard to sustain a confident diagnosis of unresponsive wakefulness syndrome solely on behavioural grounds, without PET imaging for confirmation…[This] work serves as a signpost for future studies. Functional brain imaging is expensive and technically challenging, but it will almost certainly become cheaper and easier. In the future, we will probably look back in amazement at how we were ever able to practise without it.”](http://40.media.tumblr.com/b5f14e9429e714b1dcc7b0bba537bce1/tumblr_n44a8uQ1p11rog5d1o1_500.jpg)
A functional brain imaging technique known as positron emission tomography (PET) is a promising tool for determining which severely brain damaged individuals in vegetative states have the potential to recover consciousness, according to new research published in The Lancet.
It is the first time that researchers have tested the diagnostic accuracy of functional brain imaging techniques in clinical practice.
“Our findings suggest that PET imaging can reveal cognitive processes that aren’t visible through traditional bedside tests, and could substantially complement standard behavioural assessments to identify unresponsive or “vegetative” patients who have the potential for long-term recovery”, says study leader Professor Steven Laureys from the University of Liége in Belgium.
In severely brain-damaged individuals, judging the level of consciousness has proved challenging. Traditionally, bedside clinical examinations have been used to decide whether patients are in a minimally conscious state (MCS), in which there is some evidence of awareness and response to stimuli, or are in a vegetative state (VS) also known as unresponsive wakefulness syndrome, where there is neither, and the chance of recovery is much lower. But up to 40% of patients are misdiagnosed using these examinations.
“In patients with substantial cerebral oedema [swelling of the brain], prediction of outcome on the basis of standard clinical examination and structural brain imaging is probably little better than flipping a coin,” writes Jamie Sleigh from the University of Auckland, New Zealand, and Catherine Warnaby from the University of Oxford, UK, in a linked Comment.
The study assessed whether two new functional brain imaging techniques—PET with the imaging agent fluorodeoxyglucose (FDG) and functional MRI (fMRI) during mental imagery tasks—could distinguish between vegetative and MCS in 126 patients with severe brain injury (81 in a MCS, 41 in a VS, and four with locked-in syndrome—a behaviourally unresponsive but conscious control group) referred to the University Hospital of Liége, in Belgium, from across Europe. The researchers then compared their results with the well-established standardised Coma Recovery Scale–Revised (CSR-R) behavioural test, considered the most validated and sensitive method for discriminating very low awareness.
Overall, FDG-PET was better than fMRI in distinguishing conscious from unconscious patients. Mental imagery fMRI was less sensitive at diagnosis of a MCS than FDG-PET (45% vs 93%), and had less agreement with behavioural CRS-R scores than FDG-PET (63% vs 85%). FDG-PET was about 74% accurate in predicting the extent of recovery within the next year, compared with 56% for fMRI.
Importantly, a third of the 36 patients diagnosed as behaviourally unresponsive on the CSR-R test who were scanned with FDG-PET showed brain activity consistent with the presence of some consciousness. Nine patients in this group subsequently recovered a reasonable level of consciousness.
According to Professor Laureys, “We confirm that a small but substantial proportion of behaviourally unresponsive patients retain brain activity compatible with awareness. Repeated testing with the CRS–R complemented with a cerebral FDG-PET examination provides a simple and reliable diagnostic tool with high sensitivity towards unresponsive but aware patients. fMRI during mental tasks might complement the assessment with information about preserved cognitive capability, but should not be the main or sole diagnostic imaging method.”
The authors point out that the study was done in a specialist unit focusing on the diagnostic neuroimaging of disorders of consciousness and therefore roll out might be more challenging in less specialist units.
Commenting on the study Jamie Sleigh and Catherine Warnaby add, “From these data, it would be hard to sustain a confident diagnosis of unresponsive wakefulness syndrome solely on behavioural grounds, without PET imaging for confirmation…[This] work serves as a signpost for future studies. Functional brain imaging is expensive and technically challenging, but it will almost certainly become cheaper and easier. In the future, we will probably look back in amazement at how we were ever able to practise without it.”
A single switch dictates severity of epileptic seizures
A switch in the brain of people with epilepsy dictates whether their seizures will be relatively mild or lead to a dangerous and debilitating loss of consciousness, Yale researchers have found.
The study published April 11 in the journal Neurology showed that there was no gradation of impairment during seizures — subjects were either alert or totally unaware of their surroundings.
The existence of an “all or none” switch for consciousness surprised researchers, who expected to find different levels of awareness among those who experience focal seizures, or those localized to particular brain areas.
“During seizures patients may report a funny, fearful feeling, tingling in their arm or some quirk in their vision but are able to answer all our questions,” said Dr. Hal Blumenfeld, professor of neurology, neurobiology, and neurosurgery, and senior author of the study. “At other times — boom — all of a sudden they are in a daze, unable to respond to their environment.”
Blumenfeld said previous studies have shown that this switch rests in areas of the brain stem that play a role in waking and in paying attention to your surroundings. The findings suggest that existing drugs that treat narcolepsy or therapies like deep brain stimulation might help patients with intractable epilepsy.
“Our goal is to prevent seizures, but in a fifth to a quarter of people have seizures no matter what we do,” Blumenfeld said. “For them, therapies that would prevent loss of consciousness would greatly improve quality of life.”
The study, part-funded by the Medical Research Council (MRC) and published online in PNAS, challenges the idea that suppressed memories remain fully preserved in the brain’s unconscious, allowing them to be inadvertently expressed in someone’s behaviour. The results of the study suggest instead that the act of suppressing intrusive memories helps to disrupt traces of the memories in the parts of the brain responsible for sensory processing.
The team at the MRC Cognition and Brain Sciences Unit and the University of Cambridge’s Behavioural and Clinical Neuroscience Institute (BCNI) have examined how suppression affects a memory’s unconscious influences in an experiment that focused on suppression of visual memories, as intrusive unwanted memories are often visual in nature.
After a trauma, most people report intrusive memories or images, and people will often try to push these intrusions from their mind, as a way to cope. Importantly, the frequency of intrusive memories decreases over time for most people. It is critical to understand how the healthy brain reduces these intrusions and prevents unwanted images from entering consciousness, so that researchers can better understand how these mechanisms may go awry in conditions such as post-traumatic stress disorder.
Participants were asked to learn a set of word-picture pairs so that, when presented with the word as a reminder, an image of the object would spring to mind. After learning these pairs, brain activity was recorded using functional magnetic resonance imaging (fMRI) while participants either thought of the object image when given its reminder word, or instead tried to stop the memory of the picture from entering their mind.
The researchers studied whether suppressing visual memories had altered people’s ability to see the content of those memories when they re-encountered it again in their visual worlds. Without asking participants to consciously remember, they simply asked people to identify very briefly displayed objects that were made difficult to see by visual distortion. In general, under these conditions, people are better at identifying objects they have seen recently, even if they do not remember seeing the object before—an unconscious influence of memory. Strikingly, they found that suppressing visual memories made it harder for people to later see the suppressed object compared to other recently seen objects.
Brain imaging showed that people’s difficulty seeing the suppressed object arose because suppressing the memory from conscious awareness in the earlier memory suppression phase had inhibited activity in visual areas of the brain, disrupting visual memories that usually help people to see better. In essence, suppressing something from the mind’s eye had made it harder to see in the world, because visual memories and seeing rely on the same brain areas: out of mind, out of sight.
Over the last decade, research has shown that suppressing unwanted memories reduces people’s ability to consciously remember the experiences. The researchers’ studies on memory suppression have been inspired, in part, by trying to understand how people adapt memory after psychological trauma. Although this may work as a coping mechanism to help people adapt to the trauma, there is the possibility that if the memory traces were able to exert an influence on unconscious behaviour, they could potentially exacerbate mental health problems. The idea that suppression leaves unconscious memories that undermine mental health has been influential for over a century, beginning with Sigmund Freud.
These findings challenge the assumption that, even when supressed, a memory remains fully intact, which can then be expressed unconsciously. Moreover, this discovery pinpoints the neurobiological mechanisms underlying how this suppression process happens, and could inform further research on uncontrolled ‘intrusive memories’, a classic characteristic of post-traumatic stress disorder.
Dr Michael Anderson, at the MRC Cognition and Brain Sciences Unit said: “While there has been a lot of research looking at how suppression affects conscious memory, few studies have examined the influence this process might have on unconscious expressions of memory in behaviour and thought. Surprisingly, the effects of suppression are not limited to conscious memory. Indeed, it is now clear, that the influence of suppression extends beyond areas of the brain associated with conscious memory, affecting perceptual traces that can influence us unconsciously. This may contribute to making unwanted visual memories less intrusive over time, and perhaps less vivid and detailed.”
Dr Pierre Gagnepain, lead author at INSERM in France said: “Our memories can be slippery and hard to pin down. Out of hand and uncontrolled, their remembrance can haunt us and cause psychological troubles, as we see in PTSD. We were interested whether the brain can genuinely suppress memories in healthy participants, even at the most unconscious level, and how it might achieve this. The answer is that it can, though not all people were equally good at this. The better understanding of the neural mechanisms underlying this process arising from this study may help to better explain differences in how well people adapt to intrusive memories after a trauma”
Unpacking the toolkit of human consciousness
No matter how different they seem — the learned and contemplative neuroscientist versus the toy orangutan with a penchant for off-color jokes — almost any adult who experiences them knows that Princeton University professor Michael Graziano is the voice behind his simian puppet Kevin. Yet to most listeners, Kevin — who acts as the comic relief when Graziano publicly presents his work — nonetheless has a distinct personality and consciousness — he seems aware of and comments on his surroundings in his own unique way.
While Kevin is not “real” in the sense of being an animate biological being, Graziano, a professor of psychology and the Princeton Neuroscience Institute, suggests that humans attribute consciousness to the puppet in the same way that we attribute consciousness to each other and to ourselves. Graziano has developed a new theory of consciousness he calls the “attention schema theory” that suggests that specialized systems in the human brain compute information about the things of which a person is aware, and project the property of consciousness onto ourselves and others. In that sense, the puppet’s consciousness is every bit as real as that of anyone wincingly laughing at his jokes about living atop Graziano’s hand.
For centuries, the brain was a mystery. Only in the last few decades have scientists begun to unravel its secrets. In recent years, using the latest technology and powerful computers further key discoveries have been made.
However, much remains to be understood about how the brain works. Here are five important areas of study attempting to unlock the last secrets of the brain.
How to fix it
When we think, move, speak, dream and even love - it all happens in the grey matter. But our brains are not simply one colour. White matter matters too.
Much of the research into dementia has focused on the tell-tale plaques of beta amyloid and tau protein tangles which occur in the grey matter.
But one British scientist, Dr Atticus Hainsworth says the white matter - and its blood supply - may be equally important.
The white colour results from fatty sheaths around the axons - which are extensions of the nerve cell bodies and help the cells to communicate.
He is using banks of donated brains, in Oxford and Sheffield, to analyse white matter for potential triggers such as leaking blood vessels.
"Some of the cases had an MRI or CT scan and that information can help give more clues about whether there was disease in the white matter - and what its basis might be," says Dr Hainsworth.
If leaking blood vessels in white matter do play a key role in the development of dementia then it may offer up a another potential route for new drug therapies.
How to make us all geniuses
For years caffeine was used to enhance alertness. But popping a pill to get straight-A’s may soon become the norm.
At Cambridge University neuroscientist Barbara Sahakian is investigating cognitive enhancers - drugs which make us smarter.
She studies how they can improve the performance of surgeons or pilots and asks if they could even be used to make us more entrepreneurial.
But she warns that there is no long-term safety information on these drugs and as a society we need to talk about their use.
She says the scientific and ethical challenges created by drugs which affect the production of brain chemicals like dopamine and noradrenaline - which induce pleasurable or “fight or flight” responses - need to be debated in order to decide whether drug-tests become routine before taking an exam.
Dr Sahakian adds: “I frequently talk to students about cognitive-enhancing drugs and a lot of students take them for studying and exams.
"But other students feel angry about this, they feel those students are cheating."
How can we harness our unconscious?
People need to be on top of their game when mastering skills like playing a musical instrument or detecting a bomb.
But research suggests that our unconscious can be harnessed to help us excel.
Repeatedly playing a tricky piece of music obviously helps develop a familiarity with the bits that are most difficult.
But cellist Tania Lisboa, who’s also a researcher in the Centre for Performance Science at London’s Royal College of Music, says it also helps to send the trickier parts of a piece from her conscious to the unconscious part of her brain.
After hours of practice, a fluent musician’s brain stores how to play the piece in an area at the back of the brain called the cerebellum - literally “the little brain”.
Neuroscientist Prof Anil Seth, of Sussex University, says: “It has more brain cells than the rest of the brain put together.
"It helps to promote fluid movements.. So the conscious effort of learning how to bow a cello is moved from the cortical areas which are involved when it’s new or difficult over to the cerebellum, which is very good at producing unconscious fluent behaviour on demand."
Music and defence may not appear to have much in common, but the unconscious can also help detect potential threats, whether it’s a suspicious person in a crowd or the presence of an improvised explosive device.
The unconscious brain is really good at spotting patterns - a skill which Paul Sajda at Colombia University in New York exploits - right at the boundary of the conscious/sub-conscious.
"I can flash 10 images a second and if one of those images has something out of the ordinary..that will essentially cause me to re-orient my brain to that image - but I’m not exactly aware of what that is."
Brain activity is monitored whilst the analyst looks at images so that researchers can later see which images triggered reactions.
What dreams are for
It’s just 60 years since scientists in Chicago first noted the tell-tale “rapid eye movement” or REM sleep which we now associate with dreaming.
But our fascination with dreams dates back at least 5,000 years to ancient Mesopotamia when people believed that the soul moved out of a sleeping body to visit the places they dreamed of.
REM sleep - which occurs every 90 minutes or so - begins with signals from the base of the brain which eventually reach the cerebral cortex - the outer layer of the brain which is responsible for learning and thought.
These nerve impulses are also directed to the spinal cord, inducing temporary paralysis of the limbs.
Prof Robert Stickgold, from the Beth Israel Deaconess Medical Center for Sleep and Cognition in Boston, believes that dreams are vital for processing memory associations.
He has asked the subjects of some of his sleep studies to play Tetris - and then noted their descriptions of how they floated amongst geometric shapes in their dreams.
He’s an admirer of Japanese scanning research where the scientists could “read” the dreams of subjects as they had MRI scans.
But he says it’s hard to get people to sleep in a noisy, expensive scanner.
And the future? “I would like to see research which reveals the rules for dream construction - and how it relates to the larger concept of memory processing during sleep.”
One even more elusive goal: how to dream just happy dreams and ditch the bad ones, especially nightmares.
Can we cure unreachable pain?
Excruciating chronic pain is one of medicine’s most difficult problems to solve.
Untouched by conventional treatments like painkilling drugs, surgeons are now testing their theory that deep brain stimulation could provide relief.
It is a brain surgery technique which involves electrodes being inserted to reach targets deep inside the brain.
The target areas are stimulated via the electrodes which are connected to a battery-powered pacemaker surgically placed under the patient’s collar bone.
One of the pioneers of this technique is Prof Tipu Aziz at the John Radcliffe Hospital in Oxford.
Deep brain stimulation has been used in the past for Parkinson’s disease and depression, and is now being trialled on obsessive compulsive disorder patients as well as those in chronic pain.
One of his patients, Clive, has suffered from terrible pain for nearly a decade after an operation to remove a disc in his neck.
"Sometimes I thought that if I had an axe, I’d chop my own arm off, if I thought it would get rid of the pain."
The doctors explained to him that his brain was getting signals from his arm to his brain confused and that the electrodes could help.
In Clive’s case this was an area of the brain called the anterior cingulate.
A week after his surgery he was one of the fortunate 70% of patients for whom the deep brain stimulation provides relief.
"It’s great to be out of that pain now. Since having the implant I can sit down for longer, I am able to walk further, everything is an improvement."
Prof Aziz is treating medical conditions. But he is aware of ethical dilemmas which could arise if the technique was applied to other areas.
"Putting electrodes in targets to improve memory.
"Or you could put electrodes into people to make them indifferent to danger and create the perfect soldier."