Monthly Archives: April 2012

Can a neuroscientist read your mind?

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Are the contents of your mind really 'confidential' or will your thoughts one day be accessible to others?

Media reports into recent research have claimed that neuroscientists are now effectively able to perform ‘mind reading’. Such reporting inevitable raises ethical questions about what applications such research might eventually be put to, and, judging by some of the comments that the on-line versions of these articles have provoked, have alarmed some people regarding the eventual path that such research might take. But how accurate is the claim that neuroscientific techniques can read minds?

Early this year an article in the Guardian  ( http://www.guardian.co.uk/science/2012/jan/31/mind-reading-program-brain-words ) reported that:

‘Scientists have picked up fragments of people’s thoughts by decoding the brain activity caused by words that they hear.’

Reporting on the same experiment the Daily Mail ( http://www.dailymail.co.uk/sciencetech/article-2095214/As-scientists-discover-translate-brainwaves-words–Could-machine-read-innermost-thoughts.html ) claimed:

 ’It’s a staggering development that could have tremendous implications….judges could use mind-reading machines to find out if murder suspects are telling the truth….mind reading devices might be used to eavesdrop covertly on the most private thoughts and dreams.’

The experiment in question, conducted by Dr Brian Pasley and colleagues (1) involved the recruitment of patients who were to undergo brain surgery. The researchers placed electrodes upon the auditory areas of the brain during the period when the patients’ skulls were open and their cerebral cortex exposed. They then played the patients a sequence of different words and recorded the electrical activity generated by the auditory cortex in response to this speech. Using complex modeling procedures they were able to reconstruct the spoken words solely from the neural signals recorded by the electrodes. Furthermore they were able to successfully apply this model to the electrical responses generated by a separate set of words that had not been used in creation of the model (e.g. which were in effect ‘novel’ to the model) suggesting that the model could theoretically be applied to reconstruct any speech heard by the patient.

While these results are undoubtedly impressive, has the media coverage of them been accurate? In terms of the Guardian’s report, their claim that this represents a decoding of ‘fragments of thoughts’ seems to depend on a rather broad definition of the term ‘thoughts’. What the research did was to reconstruct auditory stimuli that the auditory cortex was in the process of analysing. What has been achieved therefore is the decoding, at a detailed level, of the perceptual process, NOT the reading of internally generated thoughts. This is a significant step away from ‘decoding thoughts’ as the  process being decoded is entirely dependent on the presentation of an external stimulus. This doesn’t therefore represent ‘mind reading’ because the same result could theoretically be achieved without reference to the brain, e.g. by taking measurements from the relevant sensory organ or by just observing the sensory stimulus itself (2). Even if the research did represent mind reading, there seems little justification for the Daily Mail’s claim that the research could lead to ‘covert eavesdropping’. It should be obvious that the methodology required not only the opening up of the participant’s skull, but also the co-operation of the participant in allowing data to be taken for the construction of the model. Furthermore what is not mentioned by either article is that the reconstructed words were not actually intelligible to a human listener, but had to be ‘recognised’ via a speech recognition algorithm (an example of the reconstructed speech can be heard here:  http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001251#s5).

Actual Mind Reading?

While the results of Dr Pasley’s study required the participant’s brains to be exposed, other neuroimaging methods are not so intrusive, and could therefore be considered closer to the covert mind-reading reported by the Mail. Magnetic Resonance Imaging (MRI) allows brain activity to be measured in a non-invasive way, so that no surgery of any kind is required (although lying down in a scanner which costs millions of pounds and is the size of a small boat, is still required, making it far from ‘covert’!). MRI studies have produced some equivalent results to that of Pasley’s study, but using visual stimuli; with images (3) and short movies (4) having been reconstructed purely from data obtained from MRI scans. Of course such results don’t represent mind reading any more than Dr Pasley’s study, since they reflect a reconstruction of external sensory information. However other MRI studies have produced results that have allowed scientists to predict processes occurring within a participant’s brain that are not directly tied to the characteristic of external stimuli. A couple of studies by Yukiyasu Kamitani and Frank Tong (5,6) have shown that models can be created that allow an observer to identify to which stimulus a participant is (covertly) attending to. In effect these studies, and others like them, use the output from the perceptual processing mechanisms of the brain to identify how ‘top-down’ influences (such as expectation and attention) are driving perception. Strictly speaking they represent mindreading as although the mental processes in question are still involved in analysing external stimuli, it is not necessarily possible to garner the information provided by the MRI data in any other way (short of asking the person themselves). This is because the ‘top-down influences’ in question arise internally from the brain, rather than being a function of the external stimulus. Neuroimaging has enabled the concept of mind reading to be taken further however, into the realms of decoding mental events that don’t rely on any external stimulation at all. Recent studies have found that it is possible to decode what broad categories of objects someone is imagining, in the absence of any coincident external stimulation (7) although the performance level of the model is reasonably modest (~ 50%). Similarly, it also appears that the results of basic decision making processes can be identified from brain activity, with decisions relating to which button to press and when to press it (8) and whether a participant in lying (9) being decipherable using models constructed in a similar way to those already described. Interestingly the neural information that allows these decisions to be decoded occurs many seconds BEFORE the decision has actually been made, highlighting how conscious actions are likely driven by brain processes that are outside conscious awareness, rather than being the result of conscious ‘free will’. Most recently such work has been extended to more complex scenarios, with MRI data being used to predict at what point in solving an algebraic problem a child is at, and whether they are performing the calculation correctly (10).

The possibility of covert mind reading?

Clearly the aforementioned examples reflect mind reading, but do they represent the top of a ‘slippery slope’ that will lead to technology that will allow the sort of covert eavesdropping envisioned by the Daily Mail? The first impediment to such technology is the process of neuroimaging itself. MRI scanners are far from being portable enough to allow forced or covert application of brain scanning. Furthermore MRI scanning involves the production of a large magnetic field and the firing of electromagnetic pulses towards the object being imaged, both functions that would be totally impractical outside a controlled, isolated environment. Other neuroimaging methods, such as EEG, function by recording the electrical remnants of brain activity from outside the skull, and are therefore cheaper and more portable than MRI. However they lack the spatial resolution that would be required for any sophisticated mind reading application, and in any case they are extremely sensitive to external noise, again making them unsuitable for use outside of controlled environments.

Even if we assume that future technological advances would allow systems to be developed that would enable covert collection brain activity data, would such technology enable your innermost thoughts to be deciphered? There are a number of reasons to doubt that this would be possible. Current mind reading models are only able to distinguish between very broad categories of thoughts, or between very coarse categories of decisions (e.g. lie/truth, attending to one or other stimulus). To be able to read the specific details of an individual’s thoughts you would need models that distinguished between the literally billions of different things that someone could be thinking about, and the multitude of different decisions that they could make. To even create such models would involve the co-operation of individuals in a data collection process that would take an incalculable length of time. Even if such data were collected, and the subsequent required level of computation to create accurate models were possible, the ability to generalize such models to the brain activity of other individuals would rely on an assumption that every person’s brain being identical in terms of where different individual thoughts and memories are stored. This seems extremely unlikely, and is in fact counter to what we know about individual differences in brain anatomy and function. Thus while it is possible to aggregate data across participant to produce mind-reading for coarse decisions, it would be impossible to replicate such a method to distinguish between more subtle categories of thought. Even in situations where co-operation of the participant is attained, and only a coarse distinction between different psychological states is required, such mind reading techniques are problematic. Taking the example of the mooted ‘MRI Lie detector’ such a system will always be somewhat unreliable because, just like the current physiological lie detectors, they could be easily deceived if the participant can train themselves to act as if the truth is a lie (or vice versa). This is because the brain activity which is associated with lying most likely relates to the emotional and cognitive processes involved in creating a false story, rather than to lying per se. It follows that simply engaging in these same emotional and cognitive processes while telling the truth should produce neural activity which mimics that produced by a lie. If even the decoding of simple decisions can be subverted easily, it would seem impossible that attempts at more subtle discriminations of different thoughts would not be subject to even greater uncertainty. Finally it is important to note that all the forms of mind reading reviewed here are the result of probabilistic calculations. The parts of the brain that are deemed active at a certain point in time are the result of statistical computations as to whether a small signal is reflective of task-related neural activity or noise. Likewise the classification of such activity as belonging to one category of thought/decision over another is also based off probabilistic inference. There is no certainty in such a process; in fact it is fraught with uncertainty.

To conclude it seems very unlikely that neuroimaging methods will ever be able to perform the sort of mind reading predicted by scare stories in the press. In some cases such methods may not even represent a particular improvement on the sort of mind reading applications that already exist. What the mind reading research discussed in this article does allow is a greater understanding of how the brain works, which in turn provides insight into how the brain achieves the myriad feats it performs so frequently with apparent ease. The most fruitful practical application of such knowledge is likely to be in the treatment of patients with brain damage. For example the limited mind reading functions possible from existing neuroimaging methods may allow technology to be developed that would allow patients who suffer from brain damage to the extent that they cannot communicate using their peripheral nervous system, some primitive form of communication through their brain activity. In contrast your private thought and memories are likely to remain safe from the prying eyes of neuroscientists!

Image (top right) courtesy of Idea Go:  http://www.freedigitalphotos.net/images/view_photog.php?photogid=809

References

(1) Pasley BN, David SV, Mesgarani N, Flinker A, Shamma SA, et al. (2012) Reconstructing Speech from Human Auditory Cortex. PLoS Biol 10(1): e1001251. doi:10.1371/journal.pbio.1001251 http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001251

(2) Tong, F. & Pratte, M.S. (2012) Decoding Patterns of Human Brain Activity. Annual Review of Psychology, 63: 483-509.  http://www.ncbi.nlm.nih.gov/pubmed/21943172

(3)  Miyawaki, Y. Uchida, H. et al (2008) Visual Image Reconstruction from Human Brain Activity using a Combination of Multi-scale Local Image Decoders.. Neuron 60, 915–929, http://iopscience.iop.org/1742-6596/197/1/012021

(4)  Nishimoto, S., Vu, A.T., et al (2011) Reconstructing Visual Experiences from Brain Activity Evoked by Natural Movies. Current Biology 21, 1641–1646 http://www.sciencedirect.com/science/article/pii/S0960982211009377

(5) Kamitani Y, Tong F. 2005. Decoding the visual and subjective contents of the human brain. Nat. Neurosci. 8:679–85  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1808230/

(6) Kamitani Y, Tong F. 2006. Decoding seen and attended motion directions from activity in the human visual cortex. Curr. Biol. 16:1096–102 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1635016/

(7) Reddy, L., Tsuchiya, N. & Serre, T. (2010). Reading the mind’s eye: Decoding category information during mental imagery. Neuroimage. 50(2) 818-825  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2823980/

(8) Soon CS, Brass M, Heinze HJ, Haynes JD. 2008. Unconscious determinants of free decisions in the human brain. Nat. Neurosci. 11:543–45  http://www.nature.com/neuro/journal/v11/n5/full/nn.2112.html

(9) Davatzikos C, Ruparel K, Fan Y, Shen DG, Acharyya M, et al. 2005. Classifying spatial patterns of brain activity with machine learning methods: application to lie detection. NeuroImage 28:663–68  http://www.sciencedirect.com/science/article/pii/S1053811905005914

(10) Anderson, J.R. (2012) Tracking Problem Solving by Multivariate Pattern Analysis and Hidden Markov Model algorithms. Neuropsychologia, 50(4) 487-498. http://www.sciencedirect.com/science/article/pii/S0028393211003605

 

Scientists Implant Biofuel Cell in Living Snail

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By Maria Panagiotidi

Researchers led by Evgeny Katz, the Milton Kerker Chaired Professor of Colloid Science at Clarkson University, have implanted a biofuel cell in a living snail. Their findings were published in the Journal of The American Chemical Society.

Researchers led by Evgeny Katz, the Milton Kerker Chaired Professor of Colloid Science at Clarkson University, have implanted a biofuel cell in a living snail. This is the first incidence of an implanted biofuel cell continuously operating in a snail and producing electrical power over a long period of time using the snail’s physiologically produced glucose as a fuel. (Credit: Image courtesy of Clarkson University)

The “implanted battery” can generate electrical power for several months driven by glucose, which is produced by the snail.

This is the first reported incident of an implanted biofuel cell operating in a snail and producing electrical power over a long period of time using as fuel the glucose that is physiologically generated by its host.

Implantable biofuel cells have been suggested as sustainable micropower sources operating in living organisms, but such systems are still very challenging to design. In the future, implanted fuel cells that are driven by glucose generated by their host could power medical devices in humans or environmental sensors in animals.

Evgeny Katz and his colleagues made the electrodes of their fuel cell out of densely packed carbon nanotubes, and attached glucose-oxidizing and oxygen-reducing enzymes to them. The authors then implanted the electrodes into a snail (Neohelix albolabris). After decreasing the rate of current extraction to match the snail’s slow glucose transport and metabolism, they got continuous electrical output for an hour. The amount of electricity produced was far below that of just one AAA battery, but the group of scientists aim to increase it in future experiments. The fuel cell remained functional in the snail for several months during which the animal was allowed to roam freely and live an almost normal life.

The aim of this research is creating insect cyborgs, an idea that has been funded by the U.S. Department of Defense.

 

Reference

Lenka Halámková, Jan Halámek, Vera Bocharova, Alon Szczupak, Lital Alfonta, Evgeny Katz. Implanted Biofuel Cell Operating in a Living Snail. Journal of the American Chemical Society, 2012; : 120308155036002 DOI:10.1021/ja211714w

You can find the article here:  http://pubs.acs.org/doi/abs/10.1021/ja211714w 

 

 

Greedy Black Holes Eat Two Meals at a Time

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By Stephen Sadler

Researchers at the University of Leicester may have solved a long-standing mystery in astrophysics, namely: how do black holes grow so massive? In a recent paper in the journal Notes of the Royal Astronomical Society, Christopher Nixon and Andrew King from the University of Leicester, along with their collaborator Daniel Price from Monash University in Australia, put forward a new theory of black hole growth in which the gluttonous space-time singularities are able to put on weight more than 100 times faster than their conventional diet allows.

Black holes are ubiquitous in the universe, but the real heavyweights reside at the centre of galaxies like our own Milky Way, and can weigh in anywhere up to 10 billion times the mass of the Sun. They grow by a process called accretion, gobbling up gas from a disc around their equator as it gradually loses angular momentum and spirals inwards, like water down a plug hole.

Except that this can’t possibly be correct, as Professor King explains: “These hugely massive black holes were already full-grown when the universe was very young, less than a tenth of its present age.”

“We needed a faster mechanism,” says Chris Nixon, also at Leicester, “so we wondered what would happen if gas came in from different directions.”

The team made a computer simulation of a black hole orbited by two accretion discs at different angles. At the points where the discs collide, the angular momentum keeping the gas in orbit cancels out, and the gas quickly falls into the central regions, either becoming the black hole’s next meal, or recircularising into a smaller disc, depending on how much angular momentum it managed to hold onto (see picture below).

Simulation of a black hole orbited by two accretion discs, after evolving for approximately 10 orbits. The structure of the two original discs can be seen in blue, whereas the white disc near the centre is formed of gas that has collided and fallen in, before restabilising at a smaller radius.

“If two guys ride motorbikes on a Wall of Death and they collide, they lose the centrifugal force holding them to the walls and fall,” says King. The same thing happens to the gas in these discs, and it falls in towards the hole.

The regions at the centre of young galaxies provide the chaotic conditions thought to give rise to such double-disc accretion systems, providing the greedy young black holes with all the gaseous sustainence they need to grow into the giants we observe today.

 

The group’s paper can be found at: http://www.astro.le.ac.uk/~cjn12/papers/twist.pdf

Eating smelly foods could aid weight loss

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By Holly Rogers

Strongly scented foods encourage people to take smaller bites, a method commonly thought to help dieters with portion control, say researchers from Wageningen University, Netherlands.

Participants in the study were given control of how much custard they were served by pushing a button, as they were repeatedly exposed to different scents. The study showed that people would eat as much as 10% less pudding when they were presented with stronger or more unfamiliar smells.

“Bite size was associated with the aroma presented for that bite, and also for subsequent bites (especially the second to last bite),” said Dr Rene A de Wijk, project leader.

Generally, people will take smaller bites if a food is unfamiliar or unpleasant, to keep the amount of flavour they are exposed to as small as possible.

“Perhaps [...] there is an unconscious feedback loop using bite size to regulate the amount of flavour experienced,” said Dr de Wijk.

Previous research has shown the brain associates smaller bites with food that needs to be chewed more thoroughly, and can reduce how much is eaten in a single meal.

Understanding how altering the smell of food could fool the brain into believing the stomach is full would be a bonus for those trying to reduce their fat intake. Combined with healthy eating, it could even be worked into a plausible diet plan.

The team’s research has been published in the newly launched, open access journal, Flavour.

Reference

R. A. De Wijk, I. A. Polet, W. Boek, S. Conraad and J. H. F. Bult, Food aroma affects bite size, Flavour  (in press)

You can download the article from here: http://www.flavourjournal.com/content/1/1/3