Multi-Voxel Pattern Analysis of fMRI Reveals Brain Behind the Scenes

The research measured activity in a brain area known as the object-selective cortex (OSC) while participants were preparing to find a wide range of representational images of cars or people within briefly-displayed (100 ms) naturalistic scenes which they had not previously viewed. The subjects were first given visual cues that specified the category of objects (i.e., cars or people) to be located within the scenes. The key finding was that the cue alone – that is, even when no scene was subsequently shown – generated OSC responses determined through multivoxel pattern analysis (MVPA) that were strikingly similar to those that occurred when looking at actual examples of the cued category. Moreover, when looking at scenes, this neural activity pattern reliably predicted the subjects’ performance in detecting the cued visual target. (Unlike fMRI analysis, which focuses on individual brain voxels (volumetric pixels), MVPA enhances fMRI interpretation by identifying the information in broader patterns of brain activity.) _medXpress

medxpress
New tools of brain imaging are opening new windows into the brain's basic works. The study (PNAS, doi:10.1073/pnas.1101042108) described at the link breaks new ground in understanding "top-down" mechanisms used by the brain to identify objects -- when the brain has been pre-cued as to the nature of the sought object. This type of research builds general knowledge of brain function. As the tools are refined, it will become possible to better distinguish between brain responses of different individuals. The tools will then move into a clinical setting for diagnostic and screening (learning disorders, dementia, etc.) purposes.

While the technology used was already established, and so did not present significant challenges, Peelen notes that it takes six seconds to measure a neural signature – so it was needed to overcome the way neural measurements had previously been confounded with visual activity. “We came up with a clever design in which we showed the visual cue without subsequently displaying a scene,” he adds. “Since we primary gathered data using this technique, the measured signal reflected brain activity in the absence of visual input.”

Given the brain’s ability to perceive the world using various senses, and the fact that the research relied on symbolic (rather than visually-specific) cues invoked OSC activity, Peelen says that he expects that his results would be similar with different types of symbolic cues, whether these are spoken or textual. “Indeed, if we search for something in our daily life environment, the trigger to search can come from multiple sources – that is, a thought, but also an external demand – and it is unlikely that the brain has developed different mechanisms for each of these different cues. A very interesting question is how the brain transforms a symbolic cue, such as a word, a thought, or spoken text, to a visual ‘search template’ that effectively guides visual search. Very little is known about this transformation process.” _MedXpress

Different brains are wired differently. Early brain research finds ways in which brains work alike. More refined research discovers and delineates differences. As brain imaging tools grow ever more sophisticated, the powerful drive to learn more about the human brain will run head-on into the obstinate and entrenched forces of political correctness.

Which do you think will win, ultimately?

Consciousness and Frontiers in Brain Imaging:

The machine itself is a portable, light-weight monitor, which can fit on a small trolley. It has 32 electrodes that are fitted around the patient's head. A small, high-frequency electric current (too small to be felt or have any effect) is passed between two of the electrodes, and the voltages between other pairs of electrodes are measured in a process that takes less than one thousandth of a second.

An "electronic scan" is thus carried out and the machine does this whole procedure 100 times a second. By measuring the resistance to current flow (electrical impedance), a cross sectional image of the changing electrical conductivity within the brain is constructed. This is thought to reflect the amount of electrical activity in different parts of the brain. The speed of the response of fEITER is such that the evoked response of the brain to external stimuli, such as an anaesthetic drug, can be captured in rapid succession as different parts of the brain respond, thus tracking the brain's processing activity. _SD

EIT Images in Six Subjects
Researchers at the University of Manchester have created 3-D images of the brain in the act of losing consciousness. They were using a relatively new brain imaging technique called functional Electrical Impedance Tomography (fEIT). fEIT can measure brain electrical activity directly with a rapid time resolution in milliseconds.

More on the study from U. of Manchester:

Brian Pollard, Professor of Anaesthesia at The University of Manchester (UK), will tell the European Anaesthesiology Congress in Amsterdam that the real-time 3-D images seemed to show that losing consciousness involves a change in electrical activity deep within the brain, changing the activity of certain groups of nerve cells (neurons) and hindering communication between different parts of the brain.

He said the findings appear to support a hypothesis put forward by Professor Susan Greenfield, of the University of Oxford, about the nature of consciousness itself. Prof Greenfield suggests consciousness is formed by different groups of brain cells (neural assemblies), which work efficiently together, or not, depending on the available sensory stimulations, and that consciousness is not an all-or-none state but more like a dimmer switch, changing according to growth, mood or drugs. When someone is anaesthetised it appears that small neural assemblies either work less well together or inhibit communication with other neural assemblies.
"Our findings suggest that unconsciousness may be the increase of inhibitory assemblies across the brain's cortex. These findings lend support to Greenfield's hypothesis of neural assemblies forming consciousness," said Prof Pollard.

..."We have been able to see a real time loss of consciousness in anatomically distinct regions of the brain for the first time. We are currently working on trying to interpret the changes that we have observed. We still do not know exactly what happens within the brain as unconsciousness occurs, but this is another step in the direction of understanding the brain and its functions."

The team at Manchester is one of many worldwide teams investigating electrical impedance tomography (EIT), but this is its first application to anaesthesia. Prof Pollard said that a huge amount of research still needed to be done to fully understand the role EIT could play in medicine.

"If its power can be harnessed, then it has the potential to make a huge impact on many areas of imaging in medicine. It should help us to better understand anaesthesia, sedation and unconsciousness, although its place in medicine is more likely to be in diagnosing changes to the brain that occur as a result of, for example, head injury, stroke and dementia _SD

This new functional brain imaging technology has the potential for scaling to rather small, portable machines, suitable for use in a wide range of locations and situations. While temporal resolution is excellent, spatial resolution will require a lot of improvement if the tool is to be used as a diagnostic or screening device, beyond the current role in research.

From Wellcome.ac.uk: "Functional brain imaging is now an essential tool, and is well established in medicine.

The need for brain imaging is increasing with growing concern over neurodegenerative diseases, such as Alzheimer's; hence there are larger numbers of patients to be routinely scanned than ever before. Current scanners are not available in every hospital due to their high cost. Where they are available they are large, noisy, fixed installations that are not portable. Professor Hugh McCann and Dr Chris Pomfrett from the University of Manchester have been awarded translational funding to develop a newly discovered technique called 'functional electrical impedance tomography of evoked responses' (fEITER), which is directly sensitive to the brains electrical operation. This tool will enable screening of large populations, and prompt action to be taken in emergencies. The scans could be performed wherever the patient is, even at home. _Wellcome.ac.uk"

With the rapid aging of populations in the more developed world and in emerging nations, the need for such a portable screening tool for dementia and other neurodegenerative diseases should be obvious. In the lab, it is very likely that exciting new research tools of this type will make large numbers of startling discoveries about what makes our brains tick. In the ICU and Emergency Department, rapid screening for acute catastrophic brain events will prove life-saving. Once perfected, even ambulance crews may carry future generations of such devices.

As for the main story above: the brain being caught in the act of losing consciousness by fEIT? To make the most of such research, better spatial resolution will be needed.

Sublime Ecstasy and Exquisite Agony

SciAm
Love is a delicate but compelling medley of dynamic brain networks. Swept by a torrent of hormones and neurotransmitters, the brain-in-love is released from many ordinary worries and concerns -- and firmly compelled by others.

When one gives themselves up to their feelings of love -- when she let's herself go -- she can experience one of the ultimate pleasures of life: the beautiful agony.

... researcher Janniko Georgiadis said the OFC may be the basis for 'sexual control', and that by 'letting go' women can induce orgasm.

He said: 'I don't think orgasm turns off consciousness but it changes it.

'When you ask people how they perceive their orgasm, they describe a feeling of a loss of control.' _DailyMail

Beautiful agony - Watch more Funny Videos
The pleasures of love -- both orgasmic and non-orgasmic -- are addictive just as surely as any drug of pleasure. Withdrawal is a painful and disorienting experience, leading many to try to grasp the fading remnants in an iron grip.

But it is the letting go that opens the floodgates of the love experience. That is the hardest to learn.

Cross-posted to Al Fin, You Sexy Thing!
More:

Female Orgasm MRI DailyMail

To create the scans, Dutch researchers stripped strapped the women into an MRI scanner and then allowed their partners to pleasure them to orgasm, all the while taking snapshots of their brain activity.

It is hoped that by comparing the brain scans of women having an orgasm with those who cannot, scientists will be able to 'coach' those with anorgasmia into truly 'letting go'.

Kenneth Casey at the University of Michigan explained that people who suffer from chronic pain conditions can be coached to relieve some of their symptoms by altering how they thought.

Experiments proved that when people watched real-time video of their rostral anterior cingulate cortex - the site of their 'pain' - they were able to reduce their symptoms by mentally adjusting it and watching the results on screen. _DailyMail

Such real-time MRI neurofeedback as described above can be used for far more than the control of physical pain. Pleasure can be enhanced, as can cognitive skills and memory. Unpleasant memories can likewise be minimised.

We are entering a brave new world of understanding, with regard to brain states and networks. What we do with this new understanding is up to us.

More on the neuroscience of love and lust

Enlightening Video on Nerves into Brains

Starting with how neuroscientists mapped the brains of roundworms, the video moves ahead to the 3D mapping of a mouse retina and visual cortex. Finishing with the human brain connectome project, the video presents a useful introduction to how nerves fit together to make brains, for the curious.

Having a detailed 3D image of the static brain is just the beginning, of course. What you need is a dynamic 3D image of brain structure at all scales, superimposed by dynamic electromagnetic and blood flow data. In addition one would need dynamic detail at the molecular level for arterial, venous, lymphatic, CSF, intracellular and extracellular fluids and structures of the brain. Finally, one would need to know what was happening to the individual in real time -- both inside the body and outside the body.

At that point, one might begin to understand what was happening in the brain -- and perhaps take educated guesses about the mind. First person reports from the subject herself could refine one's approach.

From that preliminary position, you just take it from there, like in a jazz improvisation.

Video H/T neuropsychological.blogspot.com

Diffusion Tensor Imaging Becoming Super Brain Assessment Tool

“While particular brain regions are important for specific functions, the capacity of information flow within and between regions is also crucial,” said study leader Scientia Professor Perminder Sachdev from UNSW’s School of Psychiatry.

“We all know what happens when road or phone networks get clogged or interrupted. It’s much the same in the brain.

“With age, the brain network deteriorates and this leads to slowing of the speed of information processing, which has the potential to impact on other cognitive functions.” _Science Alert

University of New South Wales researchers have utilised advanced diffusion tensor imaging (PDF research article) along with powerful computational tools to assess the efficiency of the total brain network of white matter, and watched overall brain processing speeds as they slow due to ageing.

The research team, led by Scientia Professor Perminder Sachdev from the UNSW School of Psychiatry, has mapped the network of fibres or ‘white matter’ for the first time, allowing them to examine the strength of connections between different cortical regions, or ‘grey matter’, which are responsible for specific functions. In the past, most research has focused on the more complicated grey matter without looking at how information flows between separate regions.

A new type of magnetic resonance imaging (MRI) called diffusion tensor imaging (DTI) combined with powerful computers allowed the team to create the map and see the whole network in great detail.

“Using a mathematical theory you can see how strongly the different regions are connected to each other,” Professor Sachdev said. “You can basically look at the efficiency of the network and with ageing, we can see a reduction in the efficiency of these networks.”

“What we wanted to see is how this relates to cognitive function, and we found that the best relationship was with processing speed, which makes sense because we’re talking about strength of information connections.”

Other areas strongly affected by the efficiency of neural networks were executive functions that manage other brain processes and the ability to navigate in space, known as visuospatial function.

Sachdev said the findings could help to some extent with dementia research, by offering another way of looking at the condition, but had already helped explain what happens in the brain when physical reaction time slows down in older people.

“It’s not that they can’t do the task, it just takes longer, and we have shown that this is related to structural changes in the brain, in terms of its neural networks.”

“The next step is looking at what determines the efficiency of these networks. We want to see if they are flexible or plastic, and whether maybe we can intervene.”

...The results of the study, which was based on a sample of 342 healthy people aged between 72 and 92, have been published in the January edition of the Journal of Neuroscience. _AustralianAgeingAgenda

Here is more from science alert Australia:

In the study, the researchers performed magnetic resonance imaging (MRI) scans on 342 healthy individuals aged 72 to 92, using a new imaging technique called diffusion tensor imaging (DTI).

Using a mathematical technique called graph theory, they plotted and measured the properties of the neural connectivity they observed.

“We found that the efficiency of the whole brain network of cortical fibre connections had an influence on processing speed, visuospatial function – the ability to navigate in space – and executive function,” said study first author Dr Wei Wen.

“In particular greater processing speed was significantly correlated with better connectivity of nearly all the cortical regions of the brain.”

Professor Sachdev said the findings help explain how cognitive functions are organised in the brain, and the more highly distributed nature of some functions over others. _Science Alert

It is important to stress the difference between speed of nerve transmission and speed of information processing for the brain. The two are related, and both are measurable (or calculable) using the DTI computational techniques, but information processing is a much higher order process than mere nerve conduction velocities. Knowing processing speeds -- particularly being able to compare whole brain processing and subsystem processing speeds and efficiencies -- provides more information.

Diffusion Tensor Imaging (DTI) can be used to assess several aspects of brain functioning, including general intelligence and executive function. It can also be used to assess multiple types of brain pathology, including schizophrenia.

Better brain imaging techniques provide clinicians and researchers with better information with which to form theories and plan therapies. As brain ageing comes to be seen more as a reversible pathology, more advanced diagnostic tools and therapeutic methods will be made available more widely.

Cross-posted from an earlier Al Fin Longevity posting

Beware the Spying Optical Needle: It Can See Your Thoughts

Dubbed the optical needle, it is 500 to 1,000 microns in diameter at its tip—about half the width of a grain of rice. While the device resembles a scaled-down version of the endoscopes now commonly used for surgery, the tiny lens is slightly different. The small size of the device means that a curved lens, typical in most microscopes, is impractical. Instead, its lens is made from a material that has internal variations in its refractive profile to guide rays of light.

...In the new study, published online this month in Nature Medicine, researchers demonstrate that they can use the micro-endoscope to observe the same spot in the brain over time. _TechnologyReview

Brain_Probe
Brain probes are becoming smaller and more clever. The "optical needle" is a micro-endoscopic probe from Stanford, which is capable of long-term direct observation of local brain circuits, deep inside the brain.

A new type of micro-endoscope lets scientists watch nerve cells and blood vessels deep inside the brain of a living animal over days, weeks, or even months. A team led by Mark Schnitzer, associate professor of biology and applied physics at Stanford University, developed the endoscope—an optical instrument used to peer into the body—along with a system to insert it into the same spot time after time. This feature allowed scientists to track changes in minute features, such as the connections between cells in the brain.

"I think it will be a potent tool for tracking properties of cells over long periods of time in response to changes in the environment, over the course of learning, during aging or the progression of disease," says Schnitzer. Some developmental and neurodegenerative diseases, for example, damage connections between neurons deep in the brain.

Of particular interest to neuroscientists is the hippocampus, an area deep in the brain that is crucial to memory. Previously, scientists had been able to look at regions such as this one in detail only with highly invasive methods and at a single point in time. "But a lot of brain disorders occur slowly," says Schnitzer. "We don't just want a snapshot, we want a time-lapse [movie] on a time scale that is relevant to the progression of the disease." _TechnologyReview

The researchers first insert a tiny indwelling guide tube, then pass the optical needle through the tube for optical micro-imaging. Since the tube remains in the same location, the researchers can come back time and again to image the same location -- providing an ongoing time-lapse record of changes in cellular structure at that spot. The tool should provide many opportunities for study, and eventual clinical application.

By placing guide tubes in strategic locations around a brain tumour, for example, clinicians might be able to monitor the effects of experimental treatments.

But what about seeing your thoughts? Be patient, grasshoppers. Current optical needle technology can observe changes in the micro-structure of local brain circuits. As the technology improves, distributed observers will be able to watch a brain learning with experience. Combined with sophisticated deep brain stimulation and advanced neurofeedback, a sufficiently motivated mad scientist could learn to play any human brain like a piccolo.

fMRI Neurofeedback Opening Windows into the Brain

TechnologyReviewWhen most psychologists think of neurofeedback, they think of EEG feedback. Certainly EEG feedback has accomplished some amazing clinical and scientific results, and is even beginning to show up in mainstream gaming applications. But the state of the art in neurofeedback and brain-machine interfacing is shifting to fMRI, due to a superior spatial resolution over the entire brain. (the actual state of the art may be combined EEG plus fMRI, but let's just look at fMRI for now)

U Penn researchers recently used fMRI neurofeedback in an attempt to discover if they could teach cocaine addicts to control certain brain functions.

Childress asked 11 healthy controls and three cocaine addicts to watch a feedback screen while alternately envisioning two 30-second scenarios: Repeatedly swatting a tennis ball to someone, and navigating from room to room in a familiar place. By analyzing whole-brain activity, researchers found that a part of the brain called the supplementary motor area was most active during an imagined game of tennis. They then linked this pattern to an upward movement of a computer cursor. They did the same with the navigation task, linking it to downward movement of the cursor. After four cycles or fewer—less than five minutes of training—the subjects had learned to alternate between the two states of mind, as well as associate each one with its corresponding cursor position. From there onward, they could move the cursor up or down with their thoughts.

...The researchers found that both addicts and healthy people could control their state of mind equally well, something Childress says is encouraging for future studies. "The patients who have trouble controlling their craving could still demonstrate control over this sort of non-emotional test," she says. That confirms what earlier studies had suggested: Addicts' cognitive control issues are not linked to more general thinking, but instead limited to more emotionally charged thoughts, like cravings.

However, Childress's team will need to develop specialized tasks to figure out how to apply this to addiction and other disorders. For therapy, "You really need feedback from localized regions that have to do with their disease, and have people learn to control them," says Rainer Goebel, a professor of psychology at the University of Maastricht in the Netherlands who has done similar work with depression patients. _TechnologyReview

As mentioned parenthetically above, the combination of EEG plus fMRI neurofeedback offers a superior tool, in that both spatial and time resolutions are optimised. When using neurofeedback to facilitate a brain-machine interface, one wants to optimise time resolution. When using neurofeedback to train in controlling brain responses, one would want optimal spatial resolution. As training programs become more specialised, each small improvement in spatial and temporal resolution will be treasured by researchers.

Powerful EEG neurofeedback tools have been used for assisting in brain rehabilitation after brain trauma or infarct, in treating severe autism, for treating depression, and in other neuro-psychiatric conditions. Clinicians are typically more daring than researchers when using such relatively safe tools, given the difference between the clinical environment and the research culture. Researchers are quite cautious, and appear almost plodding in their careful step by step approach to scientific knowledge. Clinicians, on the other hand, are often desperate to help in cases which seem hopeless. They are willing to take intuitive leaps, and work with what they find.

The difference between attempting to build a structure of knowledge from the bottom up, brick by brick, vs. the sudden achievement of disconnected but profound findings when taking a leap of faith, contributes to the wall of incomprehension which often grows between the research and the applied branches of a given science.

As fMRI neurofeedback tools (and combined fMRI-EEG tools) eventually move from the hospital and lab into the outpatient clinical setting, the possibilities of sophisticated feedback tools combined with VR techniques in normal brains, should be astounding. Non-invasive, non-toxic tools such as neurofeedback, offer little risk in comparison with surgical, pharmaceutical, invasive electrical, and radiologic tools that might be used in a clinical setting. Clinicians typically feel free to try new and unconventional approaches when there is little to lose and much to gain.

Al Fin Futurists place the transformative potential of advanced neurofeedback technologies at the highest setting.

IQ and HBD Deniers Being Backed Into a Corner

The project is novel in its size; most brain-imaging studies have looked at tens to hundreds of brains. Scanning so many people will shed light on the normal variability within the brain structure of healthy adults, which will in turn provide a basis for examining how neural "wiring" differs in such disorders as autism and schizophrenia.

The researchers also plan to collect genetic and behavioral data, testing participants' sensory and motor skills, memory, and other cognitive functions, and deposit this information along with brain scans in a public database (although the patients' personal information will be stripped out). Scientists around the world can then use the database to search for the genetic and environmental factors that influence the structure of the brain. _TR

Technology Review provides more information on the Human Connectome Project, sponsored by NIH. The ambitious project aims to do far more than to build more accurate maps of the human brain connectome. This project aims to do some genuine cognitive science. And that is likely to make a lot of HBD (human biodiversity) deniers very nervous.

"We want to learn as much as we can, not only about the typical patterns of brain connectivity, but also about the differences in wiring that make each of us a unique individual," says David Van Essen, a neuroscientist at Washington University in St. Louis, who is one of the project leaders. "If you're good at math, and I'm better at certain types of memory, can we identify some of the wiring characteristics that account for those differences?"

The most detailed studies to date of the neural circuits that connect one brain cell to another have focused on animal brains, because scientists can examine the animals' living tissue cells and their networks under a microscope. "We don't know how our species specifically is wired up," says Michael Huerta, associate director of the Division of Neuroscience and Basic Behavioral Science at the National Institute of Mental Health, and director of the Connectome project. "There is an entire class of data that is missing from neuroscience that is fundamentally important for how the brain works and how it breaks down in different disorders." And because researchers will be scanning only identical and fraternal twins and their siblings, the scientists can get a sense of the role that genetics and environment play in shaping brain structure. Structures of the brain that are highly dictated by genes will be more similar in identical twins than in fraternal twins, for example. _TR

There are more technical details at the link above. It promises to be a fascinating project on many levels.

Perhaps the scientists involved in the huge project have not yet taken the pledge of strict political correctness. Perhaps they have not gotten the memo directing them to avoid any research which might be used to explain cognitive or behavioural differences on the basis of genetics.

All issues of political correctness aside, the modern tools of science and computation are giving us the potential to finally understand many aspects of ourselves which had been closed to us. Some of these things may prove unsavoury, but in order to wisely move into the future we must be honest about our past and present.