̽��ֱ�� of Cambridge - James S McDonnell Foundation

One in four patients in vegetative or minimally conscious state able to perform cognitive tasks, study finds

cjb250 — Wed, 14 Aug 2024 21:00:11 +0000

Severe brain injury can leave individuals unable to respond to commands physically, but in some cases they are still able to activate areas of the brain that would ordinarily play a role in movement. This phenomenon is known as ‘cognitive motor dissociation’.

To determine what proportion of patients in so-called ‘disorders of consciousness’ experience this phenomenon – and help inform clinical practice – researchers across Europe and North America recruited a total of 353 adults with disorders of consciousness, including the largest cohort of 100 patients studied at Cambridge ̽��ֱ�� Hospitals NHS Foundation Trust.

Participants had mostly sustained brain injury from severe trauma, strokes or interrupted oxygen supply to the brain after heart attacks. Most were living in specialised long-term care facilities and a few were living at home with extensive care packages. ̽��ֱ��median time from injury for the whole group was about eight months.

Researchers assessed patterns of brain activation among these patients using functional magnetic resonance imaging (fMRI) or electroencephalography (EEG). Subjects were asked to repeatedly imagine performing a motor activity (for example, “keep wiggling your toes”, “swinging your arm as if playing tennis”, “walking around your house from room to room”) for periods of 15 to 30 seconds separated by equal periods of rest. To be able to follow such instructions requires not only the understanding of and response to a simple spoken command, but also more complex thought processes including paying attention and remembering the command.

̽��ֱ��results of the study are published today in the New England Journal of Medicine.

Dr Emmanuel Stamatakis from the Department of Clinical Neurosciences at the ̽��ֱ�� of Cambridge said: “When a patient has sustained a severe brain injury, there are very important, and often difficult, decisions to be made by doctors and family members about their care. It’s vitally important that we are able to understand the extent to which their cognitive processes are still functioning by utilising all available technology.”

Among the 241 patients with a prolonged disorder of consciousness, who could not make any visible responses to bedside commands, one in four (25%) was able to perform cognitive tasks, producing the same patterns of brain activity recorded with EEG and/or fMRI that are seen in healthy subjects in response to the same instructions.

In the 112 patients who did demonstrate some motor responses to spoken commands at the bedside, 38% performed these complex cognitive tasks during fMRI or EEG. However, the majority of these patients (62%) did not demonstrate such brain activation. This counter-intuitive finding emphasises that the fMRI and EEG tasks require patients to have complex cognitive abilities such as short-term memory and sustained concentration, which are not required to the same extent for following bedside commands.

These findings are clinically very important for the assessment and management of the estimated 1,000 to 8,000 individuals in the UK in the vegetative state and 20,000 to 50,000 in a minimally conscious state. ̽��ֱ��detection of cognitive motor dissociation has been associated with more rapid recovery and better outcomes one year post injury, although the majority of such patients will remain significantly disabled, albeit with some making remarkable recoveries.

Dr Judith Allanson, Consultant in Neurorehabilitation, said: “A quarter of the patients who have been diagnosed as in a vegetative or minimally conscious state after detailed behavioural assessments by experienced clinicians, have been found to be able to imagine carrying out complex activities when specifically asked to. This sobering fact suggests that some seemingly unconscious patients may be aware and possibly capable of significant participation in rehabilitation and communication with the support of appropriate technology.

“Just knowing that a patient has this ability to respond cognitively is a game changer in terms of the degree of engagement of caregivers and family members, referrals for specialist rehabilitation and best interest discussions about the continuation of life sustaining treatments.”

̽��ֱ��researchers caution that care must be taken to ensure the findings are not misrepresented, pointing out, for example, that a negative fMRI/EEG result does not per se exclude cognitive motor dissociation as even some healthy volunteers do not show these responses.

Professor John Pickard, emeritus professorial Fellow of St Catharine's College, Cambridge, said: “Only positive results – in other words, where patients are able to perform complex cognitive processes – should be used to inform management of patients, which will require meticulous follow up involving specialist rehabilitation services.”

̽��ֱ��team is calling for a network of research platforms to be established in the UK to enable multicentre studies to examine mechanisms of recovery, develop easier methods of assessment than task-based fMRI/EEG, and to design novel interventions to enhance recovery including drugs, brain stimulation and brain-computer interfaces.

̽��ֱ��research reported here was primarily funded by the James S. McDonnell Foundation. ̽��ֱ��work in Cambridge was supported by the National Institute for Health and Care Research UK, MRC, Smith’s Charity, Evelyn Trust, CLAHRC ARC fellowship and the Stephen Erskine Fellowship (Queens’ College).

Reference
Bodien, YG et al. Cognitive Motor Dissociation in Disorders of Consciousness. NEJM; 14 Aug 2024; DOI: 10.1056/NEJMoa2400645

Adapted from a press release from Weill Cornell Medicine

Around one in four patients with severe brain injury who cannot move or speak – because they are in a prolonged coma, vegetative or minimally conscious state – is still able to perform complex mental tasks, a major international study has concluded in confirmation of much smaller previous studies.

When a patient has sustained a severe brain injury, there are very important, and often difficult, decisions to be made by doctors and family members about their care

Emmanuel Stamatakis

Witthaya Prasongsin (Getty Images)

Male patient in a hospital bed - stock image

Acknowledgements

̽��ֱ��multidisciplinary Cambridge Impaired Consciousness Research Group, led by Emeritus Professors John Pickard (Neurosurgery) & David Menon (Anaesthesia) and Drs Judith Allanson & Emmanuel A. Stamatakis (Lead, Cognition and Consciousness Imaging Group), started its research programme in 1997, partly in response to emerging concern over the misdiagnosis of the vegetative state. This pioneering work has only been possible by having access to the world class resources of the Wolfson Brain Imaging Centre, the NIHR/Wellcome Clinical Research Facility at Addenbrooke’s Hospital, the MRC Cognition and Brain Sciences Unit (Professors Barbara Wilson & Adrian Owen), the Royal Hospital for Neuro-disability (Putney) and the Central England Rehabilitation Unit (Royal Leamington Spa).

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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AI system self-organises to develop features of brains of complex organisms

cjb250 — Mon, 20 Nov 2023 16:00:47 +0000

As neural systems such as the brain organise themselves and make connections, they have to balance competing demands. For example, energy and resources are needed to grow and sustain the network in physical space, while at the same time optimising the network for information processing. This trade-off shapes all brains within and across species, which may help explain why many brains converge on similar organisational solutions.

Jascha Achterberg, a Gates Scholar from the Medical Research Council Cognition and Brain Sciences Unit (MRC CBU) at the ̽��ֱ�� of Cambridge said: “Not only is the brain great at solving complex problems, it does so while using very little energy. In our new work we show that considering the brain’s problem solving abilities alongside its goal of spending as few resources as possible can help us understand why brains look like they do.”

Co-lead author Dr Danyal Akarca, also from the MRC CBU, added: “This stems from a broad principle, which is that biological systems commonly evolve to make the most of what energetic resources they have available to them. ̽��ֱ��solutions they come to are often very elegant and reflect the trade-offs between various forces imposed on them.”

In a study published today in Nature Machine Intelligence, Achterberg, Akarca and colleagues created an artificial system intended to model a very simplified version of the brain and applied physical constraints. They found that their system went on to develop certain key characteristics and tactics similar to those found in human brains.

Instead of real neurons, the system used computational nodes. Neurons and nodes are similar in function, in that each takes an input, transforms it, and produces an output, and a single node or neuron might connect to multiple others, all inputting information to be computed.

In their system, however, the researchers applied a ‘physical’ constraint on the system. Each node was given a specific location in a virtual space, and the further away two nodes were, the more difficult it was for them to communicate. This is similar to how neurons in the human brain are organised.

̽��ֱ��researchers gave the system a simple task to complete – in this case a simplified version of a maze navigation task typically given to animals such as rats and macaques when studying the brain, where it has to combine multiple pieces of information to decide on the shortest route to get to the end point.

One of the reasons the team chose this particular task is because to complete it, the system needs to maintain a number of elements – start location, end location and intermediate steps – and once it has learned to do the task reliably, it is possible to observe, at different moments in a trial, which nodes are important. For example, one particular cluster of nodes may encode the finish locations, while others encode the available routes, and it is possible to track which nodes are active at different stages of the task.

Initially, the system does not know how to complete the task and makes mistakes. But when it is given feedback it gradually learns to get better at the task. It learns by changing the strength of the connections between its nodes, similar to how the strength of connections between brain cells changes as we learn. ̽��ֱ��system then repeats the task over and over again, until eventually it learns to perform it correctly.

With their system, however, the physical constraint meant that the further away two nodes were, the more difficult it was to build a connection between the two nodes in response to the feedback. In the human brain, connections that span a large physical distance are expensive to form and maintain.

When the system was asked to perform the task under these constraints, it used some of the same tricks used by real human brains to solve the task. For example, to get around the constraints, the artificial systems started to develop hubs – highly connected nodes that act as conduits for passing information across the network.

More surprising, however, was that the response profiles of individual nodes themselves began to change: in other words, rather than having a system where each node codes for one particular property of the maze task, like the goal location or the next choice, nodes developed a flexible coding scheme. This means that at different moments in time nodes might be firing for a mix of the properties of the maze. For instance, the same node might be able to encode multiple locations of a maze, rather than needing specialised nodes for encoding specific locations. This is another feature seen in the brains of complex organisms.

Co-author Professor Duncan Astle, from Cambridge’s Department of Psychiatry, said: “This simple constraint – it’s harder to wire nodes that are far apart – forces artificial systems to produce some quite complicated characteristics. Interestingly, they are characteristics shared by biological systems like the human brain. I think that tells us something fundamental about why our brains are organised the way they are.”

Understanding the human brain

̽��ֱ��team are hopeful that their AI system could begin to shed light on how these constraints, shape differences between people’s brains, and contribute to differences seen in those that experience cognitive or mental health difficulties.

Co-author Professor John Duncan from the MRC CBU said: “These artificial brains give us a way to understand the rich and bewildering data we see when the activity of real neurons is recorded in real brains.”

Achterberg added: “Artificial ‘brains’ allow us to ask questions that it would be impossible to look at in an actual biological system. We can train the system to perform tasks and then play around experimentally with the constraints we impose, to see if it begins to look more like the brains of particular individuals.”

Implications for designing future AI systems

̽��ֱ��findings are likely to be of interest to the AI community, too, where they could allow for the development of more efficient systems, particularly in situations where there are likely to be physical constraints.

Dr Akarca said: “AI researchers are constantly trying to work out how to make complex, neural systems that can encode and perform in a flexible way that is efficient. To achieve this, we think that neurobiology will give us a lot of inspiration. For example, the overall wiring cost of the system we've created is much lower than you would find in a typical AI system.”

Many modern AI solutions involve using architectures that only superficially resemble a brain. ̽��ֱ��researchers say their works shows that the type of problem the AI is solving will influence which architecture is the most powerful to use.

Achterberg said: “If you want to build an artificially-intelligent system that solves similar problems to humans, then ultimately the system will end up looking much closer to an actual brain than systems running on large compute cluster that specialise in very different tasks to those carried out by humans. ̽��ֱ��architecture and structure we see in our artificial ‘brain’ is there because it is beneficial for handling the specific brain-like challenges it faces.”

This means that robots that have to process a large amount of constantly changing information with finite energetic resources could benefit from having brain structures not dissimilar to ours.

Achterberg added: “Brains of robots that are deployed in the real physical world are probably going to look more like our brains because they might face the same challenges as us. They need to constantly process new information coming in through their sensors while controlling their bodies to move through space towards a goal. Many systems will need to run all their computations with a limited supply of electric energy and so, to balance these energetic constraints with the amount of information it needs to process, it will probably need a brain structure similar to ours.”

̽��ֱ��research was funded by the Medical Research Council, Gates Cambridge, the James S McDonnell Foundation, Templeton World Charity Foundation and Google DeepMind.

Reference
Achterberg, J & Akarca, D et al. Spatially embedded recurrent neural networks reveal widespread links between structural and functional neuroscience findings. Nature Machine Intelligence; 20 Nov 2023; DOI: 10.1038/s42256-023-00748-9

Cambridge scientists have shown that placing physical constraints on an artificially-intelligent system – in much the same way that the human brain has to develop and operate within physical and biological constraints – allows it to develop features of the brains of complex organisms in order to solve tasks.

Not only is the brain great at solving complex problems, it does so while using very little energy

Jascha Achterberg

DeltaWorks

Graphic representing an artificially intelligent brain

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Dementia patients struggle to cope with change because of damage to general intelligence brain networks

cjb250 — Tue, 08 Mar 2022 18:00:44 +0000

There are many different types of dementia, such as Alzheimer’s disease and frontotemporal dementia (FTD), which are characterised by the build-up of different toxic proteins in different parts of the brain. This means that the symptoms of dementia vary, and can include problems with memory, speech, behaviour or vision. But one symptom seen across every type of dementia is a difficulty in responding to unexpected situations.

Dr Thomas Cope from the MRC Cognition and Brain Science Unit and Department of Clinical Neurosciences at the ̽��ֱ�� of Cambridge said: “At the heart of all dementias is one core symptom, which is that when things change or go unexpectedly, people find it very difficult. If people are in their own environment and everything is going to plan, then they are OK. But as soon as the kettle’s broken or they go somewhere new, they can find it very hard to deal with.”

To understand why this happens, Dr Cope and colleagues analysed data from 75 patients, all of whom are affected by one of four types of dementia that affect different areas of the brain. ̽��ֱ��patients, together with 48 healthy controls, listened to changing sounds while their brain activity was recorded by a magnetoencephalography machine, which measures the tiny magnetic fields produced by electrical currents in the brain. Unlike traditional MRI scanners, these machines allow very precise timing of what is happening in the brain and when. ̽��ֱ��results of their experiment are published today in the Journal of Neuroscience.

During the scan, the volunteers watched a silent film – David Attenborough’s Planet Earth, but without its soundtrack – while listening to a series of beeps. ̽��ֱ��beeps occurred at a steady pattern, but occasionally a beep would be different, for example a higher pitch or different volume.

̽��ֱ��team found that the unusual beep triggered two responses in the brain: an immediate response followed by a second response around 200 milliseconds – a fifth of a second – a later.

̽��ֱ��initial response came from the basic auditory system, recognising that it had heard a beep. This response was the same in the patients and healthy volunteers.

̽��ֱ��second response, however, recognised that the beep was unusual. This response was much smaller among the people with dementia than among the healthy volunteers. In other words, in the healthy controls, the brain was better at recognising that something had changed.

̽��ֱ��researchers looked at which brain areas activated during the task and how they were connected up, and combined their data with that from MRI scans, which show the structure of the brain. They showed that damage to areas of the brain known as ‘multiple demand networks’ was associated with a reduction in the later response.

Multiple demand networks, which are found both at the front and rear of the brain, are areas of the brain that do not have a specific task, but instead are involved in general intelligence – for example problems solving. They are highly evolved, found only in humans, primates and more intelligent animals. It is these networks that allow us to be flexible in our environment.

In the healthy volunteers, the sound is picked up by the auditory system, which relays information to the multiple demand network to be processed and interpreted. ̽��ֱ��network then ‘reports back’ to the auditory system, instructing it whether to carry on or to attend to the sound.

“There's a lot of controversy about what exactly multiple demand networks do and how involved they are in our basic perception of the world,” said Dr Cope. “There's been an assumption that these intelligence networks work ‘above’ everything else, doing their own thing and just taking in information. But what we've shown is no, they're fundamental to how we perceive the world.

“That's why we can look at a picture and immediately pick out the faces and immediately pick out the relevant information, whereas somebody with dementia will look at that scene a bit more randomly and won't immediately pick out what’s important.”

While the research does not point to any treatments that may alleviate the symptom, it reinforces advice given to dementia patients and their families, said Dr Cope.

“ ̽��ֱ��advice I give in my clinics is that you can help people who are affected by dementia by taking a lot more time to signpost changes, flagging to them that you’re going to start talking about something different or you’re going to do something different. And then repeat yourself more when there's a change, and understand why it’s important to be patient as the brain recognises the new situation.”

Although their study only looked at patients with dementia, the findings may explain similar phenomena experienced by people living with conditions such as schizophrenia, where brain networks can become disrupted.

̽��ֱ��research was funded by the Medical Research Council and National Institute for Health Research, with additional support from Wellcome, the Biotechnology and Biological Sciences Research Council and the James S McDonnell Foundation.

Dr Cope is a fellow at Murray Edwards College, Cambridge.

Reference
Cope, TE at al. Causal Evidence for the Multiple Demand Network in Change Detection: Auditory Mismatch Magnetoencephalography across Focal Neurodegenerative Diseases. JNeuro; 8 March 2022; DOI: 10.1523/JNEUROSCI.1622-21.2022

People with dementia struggle to adapt to changes in their environment because of damage to areas of the brain known as ‘multiple demand networks’, highly-evolved areas of the brain that support general intelligence, say scientists at the ̽��ֱ�� of Cambridge.

At the heart of all dementias is one core symptom, which is that when things change or go unexpectedly, people find it very difficult

Thomas Cope

Visual Stories || Micheile

Elderly couple

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Report examines origins and nature of ‘maths anxiety’

cjb250 — Thu, 14 Mar 2019 00:01:45 +0000

̽��ֱ��report was funded by the Nuffield Foundation, with additional support from the James S McDonnell Foundation.

̽��ֱ��UK is facing a maths crisis: according to a 2014 report from National Numeracy, four out of five adults have low functional mathematics skills compared to fewer than half of UK adults having low functional literacy levels.

While mathematics is often considered a hard subject, not all difficulties with the subject result from cognitive difficulties. Many children and adults experience feelings of anxiety, apprehension, tension or discomfort when confronted by a maths problem.

A report published today by the Centre for Neuroscience in Education at the ̽��ֱ�� of Cambridge explores the nature and resolution of so-called ‘mathematics anxiety’.

Origins of maths anxiety

In a sample of 1,000 Italian students, the researchers found that girls in both primary and secondary school had higher levels of both maths anxiety and general anxiety.

More detailed investigation in 1,700 UK schoolchildren found that a general feeling that maths was more difficult than other subjects often contributed to maths anxiety, leading to a lack or loss of confidence. Students pointed to poor marks or test results, or negative comparisons to peers or siblings as reasons for feeling anxious.

“While every child’s maths anxiety may be different, with unique origins and triggers, we found several common issues among both the primary and secondary school students that we interviewed,” says Dr Denes Szucs from the Department of Psychology, the study’s lead author.

Students often discussed the role that their teachers and parents played in their development of maths anxiety. Primary-aged children referred to instances where they had been confused by different teaching methods, while secondary students commented on poor interpersonal relations.

Secondary students indicated that the transition from primary to secondary school had been a cause of maths anxiety, as the work seemed harder and they couldn’t cope. There was also greater pressure from tests – in particular, SATS – and an increased homework load.

Relationship between maths anxiety and performance

In a study published in 2018, the researchers showed that it is not only children with low maths ability who experience maths anxiety – more than three-quarters (77%) of children with high maths anxiety are normal to high achievers on curriculum maths tests.

“Because these children perform well at tests, their maths anxiety is at high risk of going unnoticed by their teachers and parents, who may only look at performance but not at emotional factors,” says Dr Amy Devine, the 2018 study’s first author, who now works for Cambridge Assessment English. “But their anxiety may keep these students away from STEM fields for life when in fact they would be perfectly able to perform well in these fields.”

However, it is almost certainly the case that in the long term, people with greater maths anxiety perform worse than their true maths ability. Today’s report includes a review of existing research literature that shows that this can lead to a vicious circle: maths anxiety leading to poorer performance and poorer performance increasing maths anxiety.

Recommendations

̽��ֱ��researchers set out a number of recommendations in the report. These include the need for teachers to be conscious that an individual’s maths anxiety likely affects their mathematics performance. Teachers and parents also need to be aware that their own maths anxiety might influence their students’ or child’s maths anxiety and that gendered stereotypes about mathematics suitability and ability might contribute to the gender gap in maths performance.

“Teachers, parents, brothers and sisters and classmates can all play a role in shaping a child’s maths anxiety,” adds co-author Dr Ros McLellan from the Faculty of Education. “Parents and teachers should also be mindful of how they may unwittingly contribute to a child’s maths anxiety. Tackling their own anxieties and belief systems in maths might be the first step to helping their children or students.”

̽��ֱ��researchers say that as maths anxiety is present from a young age but may develop as the child grows, further research should be focused on how maths anxiety can be best remediated before any strong link with performance begins to emerge.

“Our findings should be of real concern for educators. We should be tackling the problem of maths anxiety now to enable these young people to stop feeling anxious about learning mathematics and give them the opportunity to flourish,” says Dr Szucs. “If we can improve a student’s experience within their maths lessons, we can help lessen their maths anxiety, and in turn this may increase their overall maths performance.”

Josh Hillman, Director of Education at the Nuffield Foundation, said: “Mathematical achievement is valuable in its own right, as a foundation for many other subjects and as an important predictor of future academic outcomes, employment opportunities and even health. Maths anxiety can severely disrupt students’ performance in the subject in both primary and secondary school. But importantly - and surprisingly - this new research suggests that the majority of students experiencing maths anxiety have normal to high maths ability. We hope that the report’s recommendations will inform the design of school and home-based interventions and approaches to prevent maths anxiety developing in the first place.”

Background

Researchers worked with more than 2,700 primary and secondary students in the UK and Italy to examine both maths anxiety and general anxiety, and gain a measure of mathematics performance. They then worked one-to-one with the children to gain a deeper understanding of their cognitive abilities and feelings towards mathematics.

This is the first interview-based study of its kind to compare the mathematics learning experiences of a relatively large sample of students identified as mathematics anxious with similar children that are not mathematics anxious. Although further in-depth studies are needed to substantiate and expand upon this work, the findings indicate that the mathematics classroom is a very different world for children that are mathematics anxious compared to those that are not.

Reference
Understanding Mathematics Anxiety: Investigating the experiences of UK primary and secondary school students. 14 March 2019

A report out today examines the factors that influence ‘maths anxiety’ among primary and secondary school students, showing that teachers and parents may inadvertently play a role in a child’s development of the condition, and that girls tend to be more affected than boys.

While every child’s maths anxiety may be different, with unique origins and triggers, we found several common issues among both the primary and secondary school students

Denes Szucs

Pixapopz

Maths blackboard

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Being overweight linked to poorer memory

cjb250 — Thu, 25 Feb 2016 17:28:44 +0000

In a preliminary study published in ̽��ֱ��Quarterly Journal of Experimental Psychology, researchers from the Department of Psychology at Cambridge found an association between high body mass index (BMI) and poorer performance on a test of episodic memory.

Although only a small study, its results support existing findings that excess bodyweight may be associated with changes to the structure and function of the brain and its ability to perform certain cognitive tasks optimally. In particular, obesity has been linked with dysfunction of the hippocampus, an area of the brain involved in memory and learning, and of the frontal lobe, the part of the brain involved in decision making, problem solving and emotions, suggesting that it might also affect memory; however, evidence for memory impairment in obesity is currently limited.

Around 60% of UK adults are overweight or obese: this number is predicted to rise to approximately 70% by 2034. Obesity increases the risk of physical health problems, such as diabetes and heart disease, as well as psychological health problems, such as depression and anxiety.

“Understanding what drives our consumption and how we instinctively regulate our eating behaviour is becoming more and more important given the rise of obesity in society,” says Dr Lucy Cheke. “We know that to some extent hunger and satiety are driven by the balance of hormones in our bodies and brains, but psychological factors also play an important role – we tend to eat more when distracted by television or working, and perhaps to ‘comfort eat’ when we are sad, for example.

“Increasingly, we’re beginning to see that memory – especially episodic memory, the kind where you mentally relive a past event – is also important. How vividly we remember a recent meal, for example today’s lunch, can make a difference to how hungry we feel and how much we are likely to reach out for that tasty chocolate bar later on.”

̽��ֱ��researchers tested 50 participants aged 18-35, with body mass indexes (BMIs) ranging from 18 through to 51 – a BMI of 18-25 is considered healthy, 25-30 overweight, and over 30 obese. ̽��ֱ��participants took part in a memory test known as the ‘Treasure-Hunt Task’, where they were asked to hide items around complex scenes (for example, a desert with palm trees) across two ‘days’. They were then asked to remember which items they had hidden, where they had hidden them, and when they were hidden. Overall, the team found an association between higher BMI and poorer performance on the tasks.

̽��ֱ��researchers say that the results could suggest that the structural and functional changes in the brain previously found in those with higher BMI may be accompanied by a reduced ability to form and/or retrieve episodic memories. As the effect was shown in young adults, it adds to growing evidence that the cognitive impairments that accompany obesity may be present early in adult life.

This was a small, preliminary study and so the researchers caution that further research will be necessary to establish whether the results of this study can be generalised to overweight individuals in general, and to episodic memory in everyday life rather than in experimental conditions.

“We're not saying that overweight people are necessarily more forgetful," cautions Dr Cheke, “but if these results are generalizable to memory in everyday life, then it could be that overweight people are less able to vividly relive details of past events – such as their past meals. Research on the role of memory in eating suggests that this might impair their ability to use memory to help regulate consumption.

“In other words, it is possible that becoming overweight may make it harder to keep track of what and how much you have eaten, potentially making you more likely to overeat.”

Dr Cheke believes that this work is an important step in understanding the role of psychological factors in obesity. “ ̽��ֱ��possibility that there may be episodic memory deficits in overweight individuals is of concern, especially given the growing evidence that episodic memory may have a considerable influence on feeding behaviour and appetite regulation,” she says.

Co-author Dr Jon Simons adds: “By recognising and addressing these psychological factors head-on, not only can we come to understand obesity better, but we may enable the creation of interventions that can make a real difference to health and wellbeing.”

̽��ֱ��study was funded by the Medical Research Council and Girton College, ̽��ֱ�� of Cambridge, and the James S McDonnell Foundation.

Reference
Cheke, LG et al. Higher BMI is Associated with Episodic Memory Deficits in Young Adults. ̽��ֱ��Quarterly Journal of Experimental Psychology; 22 Feb 2016. DOI:10.1080/17470218.2015.1099163

Overweight young adults may have poorer episodic memory – the ability to recall past events – than their peers, suggests new research from the ̽��ֱ�� of Cambridge, adding to increasing evidence of a link between memory and overeating.

How vividly we remember a recent meal, for example today’s lunch, can make a difference to how hungry we feel

Lucy Cheke

Franck Mahon

Too many croissants yesterday... (cropped)

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Brain, body and mind: understanding consciousness

lw355 — Tue, 23 Feb 2016 10:27:50 +0000

In 10 minutes, Srivas Chennu can work out what’s going on inside your head.

With the help of an electrode-studded hairnet wired up to a box that measures patterns of electrical activity, he can monitor the firing of millions of neurons deep within the brain. A few minutes later, wheeling his trolley-held device away, he has enough information to tell how conscious you really are.

What Chennu is looking for with his electroencephalogram (EEG) is the brain’s electrical ‘signature’. At any one moment in the body’s most complex organ, networks of neurons are firing up and creating ‘brain waves’ of electrical activity that can be detected through the scalp net.

This isn’t new technology – the first animal EEG was published a century ago – but computational neuroscientist Chennu has come up with a way of combining its output with a branch of maths called graph theory to measure the level of a person’s consciousness. What’s more, he’s developing the technology as a bedside device for doctors to diagnose patients suffering from consciousness disorders (such as a vegetative state caused by injury or stroke) to work out the best course of action and to support family counselling.

“Being conscious not only means being awake, but also being able to notice and experience,” he explains. “When someone is conscious, there are patterns of synchronised neural activity arcing across the brain that can be detected using EEG and quantified with our software.”

So for a healthy brain, the brain’s signature might look like a raging scrawl of lines sweeping back and forth, as integrated groups of neurons perceive, process, understand and sort information. When we sleep, this diminishes to a squiggle of the faintest strokes as we lose consciousness, flaring occasionally if we dream.

“Understanding how consciousness arises from neural interactions is an elusive and fascinating question. But for patients diagnosed as vegetative and minimally conscious, and their families, this is far more than just an academic question – it takes on a very real significance.

“ ̽��ֱ��patient might be awake, but to what extent are they aware? Can they hear, see, feel? And if they are aware, does their level of awareness equate to their long-term prognosis?”

Chennu points to charts showing the brain signature of two vegetative patients. On one chart, just a few lines appear above the skull. In the other, the lines are so many they resemble, as Chennu describes, a multi-coloured mohican, almost indistinguishable from the signature one would see from a healthy person.

Did either of the patients wake up? “Yes, the second patient did, a year after this trace was taken. ̽��ֱ��point is, if you think that a patient will wake up, what would you do differently as a clinician, or as a family member?”

̽��ֱ��research is based on the finding that a patient in a vegetative state could respond to yes or no questions, as measured by distinct patterns of brain activity using functional magnetic resonance imaging. It was discovered by Chennu’s colleagues in the Department of Clinical Neurosciences and the Medical Research Council Cognition and Brain Sciences Unit (MRC CBSU), led by Dr Adrian Owen.

In 2011, the group found the same attention to commands could be measured using EEG – a less expensive and more widely available technology. Three years later, Chennu and Dr Tristan Bekinschtein from the CBSU, and now in the Department of Psychology, showed that their mathematical analysis of the EEG outputs was enough to measure the ambient amount of connectivity in a patient’s brain.

Chennu hopes that the machine will fill a technology gap: “Misdiagnosis of true levels of consciousness in vegetative patients continues to be around 40% and depends on behavioural examination. In part this is because there is no gold standard for the assessment of a patient’s awareness at the bedside.”

With funding from the Evelyn Trust, he will assess and follow the treatment and rehabilitation trajectory of 50 patients over a three-year period. This will be the first time that a study has linked diagnosis, treatment and outcome to regular real-time assessment of the activity of a patient’s brain.

Meanwhile he is continuing to develop the medical device with industry as part of the National Institute for Health Research Healthcare Technology Co-operative for Brain Injury, which is hosted within the Department of Clinical Neurosciences.

“Medical advances mean that we are identifying subtypes of brain injury and moving away from ‘one size fits all’ to more-targeted treatment specific for an individual’s needs,” adds Chennu, who is also funded by the James S. McDonnell Foundation and works as part of a team led by Professors John Pickard and David Menon.

Intriguingly the device could even offer a channel of communication, as Chennu speculates: “ ̽��ֱ��question that fascinates us is what type of consciousness do patients have? Perhaps we can create systems to translate neural activity into commands for simple communication – interfaces that could provide a basic but reliable communication channel from the ‘inbetween place’ in which some patients exist.

“Moreover, we think that the measurement of brain networks will provide clinically useful information that could help with therapeutics for a larger majority of patients, irrespective of whether they are able to demonstrate hidden consciousness.”

How conscious is my dog? Can robots become conscious? Are people in a vegetative state conscious? Don't miss Philosopher Professor Tim Crane and neuroscientist Dr Srivas Chennu at the Cambridge Science Festival, where they will look into our minds and wrestle with the meaning of what it is to be conscious. 'Brain, body and mind: new directions in the neuroscience and philosophy of consciousness', the Research Horizons Public Lecture, will be on Wednesday 16 March 2016, 8pm–9pm, Mill Lane Lecture Rooms, Mill Lane, Cambridge. Pre-booking required.

A bedside device that measures ‘brain signatures’ could help diagnose patients who have consciousness disorders – such as a vegetative state – to work out the best course of treatment and to support family counselling.

̽��ֱ��patient might be awake, but to what extent are they aware? Can they hear, see, feel? And if they are aware, does their level of awareness equate to their long-term prognosis?

Srivas Chennu

Electrical brain 'signatures'. ̽��ֱ��patient to the left is in a vegetative state; the patient in the middle is also in a vegetative state but their brain appears as conscious as the brain of the healthy individual at the right.

New directions in the study of the mind

We know a great deal about the brain but what does it actually mean to be conscious, asks a new research programme in the Faculty of Philosophy.

In what way are newborn babies, or animals, conscious? Why do some experiences become part of one’s consciousness yet others do not?

“It’s sometimes assumed that it’s obvious what consciousness is, and the only question is how it is embodied in the brain,” says Professor Tim Crane. “But many people now recognise that it’s not clear what it means to say that something has a mind, or is capable of thought or conscious experience. My view is that there are lots of assumptions that are being made in order to get to that conclusion and not all of the assumptions are correct.”

Crane leads a new research initiative in the Faculty of Philosophy supported by the John Templeton Foundation that aims to tackle the broad question of the essence of the mind. And to do this they are moving beyond the reductionist view that everything can be explained in terms of the nuts and bolts of neuroscience.

“That doesn’t mean we are interested in proving the existence of the immortal soul, or defending any religious doctrine – we are interested in the idea that the brain’s-eye view isn’t everything when it comes to understanding the mind.

“ ̽��ֱ��nervous system clearly provides the mechanism for thought and consciousness but learning about it doesn’t tell us everything we need to know about phenomena like the emotion of parental love, or ambition or desire. ̽��ֱ��mere fact that something goes on in your brain when you think does not explain what thinking essentially is.”

̽��ֱ��team in Cambridge are also distributing funds for smaller projects elsewhere in the world, each of which is tackling similar questions of consciousness in philosophy, neuroscience and psychology.

“Collectively we want to recognise ‘the reality of the psychological’ without saying that it’s really just brain chemicals,” adds Crane. “It’s important to face up to the fact that we are not just our neurons.”

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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