Posts Tagged ‘El cervell’

Ruth de Diego: “Previously we were trying to discover which part of the brain carried out such and such a function, but now we think about networks”

March 26th, 2014 No Comments

The ICREA-CCCB debates on “The Brain” end on Tuesday 1 April with the lecture titled “Lessons from Brain Lesions”, which is to be given by the University of Barcelona researcher Ruth de Diego. We have asked her to explain in advance why study of behaviour patterns and deficits caused by these lesions is useful in neuroscientific research.

The ICREA researcher Ruth de Diego

You are a specialist in psycholinguistics and cognitive neuroscience. Could you tell us what is studied in these two disciplines?

First of all, I am interested in psycholinguistics, by which I mean knowing how we come to understand language. While I was writing my thesis I was attracted to the neurobiological aspects of language and, in particular, how brain lesions can affect our understanding and speaking skills. When we come into contact with a new language, our brain gets to work to extract the regularities of that language, even if we don’t understand a word of it. If we land in Japan, for example, and start hearing this strange language, our brain will start to derive all kinds of statistical information, for example which sounds are most frequent, which ones tend to make sequences, and so on. Studying language is interesting because this is what most identifies us as human beings and because language governs our social relations. Hence, a brain lesion that affects one’s ability to speak greatly limits one’s quality of life.

What is the present situation of brain research?

In the past ten years there has been a second big spike in research and the amount of information we have acquired, in this case with a lot of studies on the brain’s structure and connectedness. Previously, in the more traditional approach, the brain was studied in a way that strongly emphasised localisation so efforts were made to discover which part of the brain carried out such and such a function. However, we realised that we couldn’t talk about isolated zones of the brain performing specific functions but, rather, we had to think about networks of different parts of the brain functioning synchronically, or working together and in a coordinated fashion to perform a certain function. Moreover, we now know that the brain is much more adaptable than we previously thought and that when there is a lesion it has an incredible capacity to reorganise itself and restore connections.

Why is studying patients with brain lesions useful?

It is useful because, by comparing different situations, we can discover a lot about the brain and its functions. Imagine a person who has a brain tumour that has taken a year to develop. In that brain the functioning is not exactly the same as that in a person who has not suffered a lesion because of this adaptability I just mentioned: the patient’s brain has been undergoing a process of restructuration in order to adapt to the pathology.

We use transcranial magnetic stimulation with a device that is brought up close to the outside of the head and, by means of a very powerful magnetic field, it changes the functioning of the neurones in the region it is nearest to by inhibiting or stimulating them. This stimulation induces a lesion virtually. This only lasts a certain time, from a few seconds to a quarter of an hour and, during that time, the healthy person acts as if he or she is suffering from a lesion in that part of the brain. Comparing a simulated lesion in a healthy person, whose brain structure is maintained without alterations, with someone else who has a long-term brain lesion, and who therefore does have alterations, makes it possible for us to discover many things about brain structure and function as well as about specific disorders.

Magnetic resonance of a Huntington patient

What kinds of brain lesions have you studied?

One of the illnesses we have studied is Huntington’s disease, which is quite a rare genetic disorder with a low incidence among the population. In its early stages, Huntington’s disease quite specifically affects a particular subcortical structure, a key area of the brain that has many connections with different parts of the cortex and, accordingly, many associated functions. We also study aphasia, a disorder that affects language comprehension because of a brain lesion. People with aphasia can see the image of a pear and say “banana” for example.

What is the use of studying these diseases?

Studying the whys and wherefores of such behaviour has many uses such as the rehabilitation of patients. Imagine that there are two zones of the brain connected in two ways. As a result of the adaptability I mentioned, if you have a lesion that affects one of them the other one, the intact one, will work to recover its function as much as possible. If we know that one way is obstructed but that the other neuronal network is operating, we can use and reinforce this latter way and design a particular kind of rehabilitation. I’ll give you an example. We have a study showing that there are two main zones of language processing, one of which is more concerned with motor functions like production and speech while the other is more concerned with perception and understanding of language, which is to say it’s more auditory. These two areas are joined by a bundle of connections and it seems that this connection, this ability to transform what we are listening to into a motor sequence, is very important with regard to learning new words. By this I mean that this process of repeating new words, listening to them, hearing them and pronouncing them ourselves – or this loop – enables us to learn. If a patient’s bundle of connections is broken and he or she can’t repeat the words in order to assimilate them, we can help him or her to learn words by turning to another connection that exists, this time a more semantic one. If this other path is taken it’s not possible to repeat words in order to assimilate them but we can accede to the word by giving it sense, connecting the motor and auditory parts of the brain through the structures of meaning. If I train the patient using this method there is a better chance that he or she will understand the word this way than through the obstructed path of repetition.

Would this be similar to mnemonics or the acronyms that are used for studying purposes to assimilate concepts on the basis of unrelated ideas of phrases?

Yes, it would be similar to that. Moreover, all of this has specific uses in the treatment of these disorders because knowing about the alterations in brain structure and functions in patients with Huntington’s disease, for example, enables us to detect and understand individual differences in patients suffering from this disorder. In the case of a clinical trial, we can divide the patients up according to the connections that are affected in each one of them and, by thus grouping them, a much more specific and effective treatment can be offered than if we didn’t distinguish between the different degrees of brain lesions affecting patients.

Mavi Sánchez-Vives: “In 20 seconds we can produce the illusion of ownership of a third arm”

March 19th, 2014 No Comments

On Tuesday 25 March Mavi Sánchez-Vives, ICREA research professor at the August Pi i Sunyer Biomedical Research Institute (IDIBAPS) will give a lecture titled “Brain and Virtual Reality“, the third in the ICREA-CCCB series of debates on “The Brain”. We have interviewed her in order to learn more about how the neurosciences use this cutting-edge technology.

La professora d’investigació ICREA Mavi Sánchez-Vives

What is your field of research?
I’m a neuroscientist and I use virtual reality as a tool for understanding brain functions. I’ll be speaking at the CCCB about a phenomenon that illustrates very well how expressive the brain is, and our great capacity for transforming the inner representation of our body in very short periods of time. We have different ways of knowing that the representation of our own body is in the brain, one of which is through bodily illusions, which are relatively easy to evoke, for example assigning ownership to a rubber arm. There are also numerous illusions of body transformations described in the literature, some of them known to be caused by certain brain lesions which bring about strange or bizarre alterations, as happens with people who believe they have a third arm, or have out-of-body experiences, or with the cases described by Oliver Sacks, for example the man who thinks that a leg in the bed isn’t his and he wants to be rid of it, and other such extreme cases. By means of virtual reality we can study the limits of representation of our own body by re-creating these illusions without needing to turn to people with brain lesions.

How do you use virtual reality?
Through virtual reality, we can bring about the illusion of ownership of an external body and achieve other such illusions by inducing a series of correlated stimuli which produce these illusions of transformation in very brief periods of time. In twenty or thirty seconds we can produce the illusion of ownership of a third arm by means of virtual reality, for example. The fact that these illusions can be produced so quickly leads us to think that the brain has this enormous expressiveness, and that virtual transformations pave the way for very different kinds of applications.

When you speak of virtual reality, do you mean a headset with a screen?
We speak of immersive virtual reality, with a headset, when the user sees an avatar instead of his or her normal body. These experiments have potential in many areas such as rehabilitation, training, physiotherapy and leisure activities.

What have you discovered, for example?
In the case of rehabilitation, we’re studying treatment of pain. For instance, we have published several papers showing that the colour in which a virtual arm appears to you can affect your pain threshold. If your virtual arm is red, you’re going to be more sensitive to a painful or hot stimulus, while if it’s another colour, blue for example, you’ll be less sensitive to a painful or hot stimulus. This means that the pain threshold is not stable and it can be modified depending on the visual information you receive.

These transformations can be brought about in a virtual environment but also by giving life to a robot.
Yes, body transformations can also happen if, instead of having a virtual body, one incorporates a robot body, and this robot body can be situated some distance away. I can use a virtual environment in Barcelona and see through the eyes of a robot in London, and interact and speak in that environment, so that I have a body in the place of destination. If this becomes general, such practice will have to be legislated, with new laws being passed to stipulate who is responsible in the other place, which might be on the other side of the world.

In this video from the TV programme Quèquicom you can see how a Barcelona-based journalist uses virtual reality to “beam” herself into an office in London in the guise of a robot in order to interview the scientist Mel Slater.

Albert Costa: “In bilingual people brain deterioration is slower”

March 12th, 2014 No Comments

The third series of ICREA-CCCB debates, «The Brain», continues on Tuesday 18th March with the lecture “The Bilingual Brain” by the ICREA research professor Albert Costa, one of the world’s leading scientists working in neurolinguistics. We have spoken with him and asked him to tell us in advance about some of the key areas of his research.

ICREA research professor Albert Costa

Your area of research is concerned with the way in which languages are installed in the brain in the case of bilingual speakers. Does this mean that you have identified the parts that store verbs and those that store nouns, for example?

One needs to think of the brain as being made up of circuits and not as isolated areas. By means of neuro-images we can tell which circuits are activated with speech. In the case of verbs and nouns, there are brain-damaged patients who are suddenly able to pronounce many more verbs than nouns, and other patients who start using more nouns than verbs. Hence, we see that there are some brain circuits that are more concerned with verbs and others with nouns. Starting from here, we look at bilingual speakers to see if the same circuits operate with the second language and the extent to which the organisation in the brain of the second language follows the same principles.

What should we understand by “bilingual speaker”?

Bilingualism doesn’t have a single definition as it consists of a wide range of cases. I lived in the United States for four years, for example, and I speak English with my son. Does that make me bilingual in English? Or aren’t I? Or, in the case of Catalan and Spanish, who is bilingual? The person who speaks both languages? Or only the one who speaks Catalan with his father and Spanish with his mother and must therefore have learned both languages at the same time? Every time we try to define bilingualism we leave out groups of people, so what we must do is to add adjectives to the concept of bilingualism: proficient bilingualism, of simultaneous acquisition, of successive acquisition, non-proficient, and so on.

What problems are entailed in being bilingual?

Bilingual people know fewer words in each language than monolingual people, for example. If you add up the total of all the words they know in both languages it will be greater, of course. However, a monolingual person might know 60,000 words in her language in contrast with the 40,000 a bilingual person knows in each of the two languages. If you play four hours of squash and four hours of tennis every day and I play only tennis for eight hours, I’ll play tennis better than you. Other disadvantages: it is more difficult for the bilingual person to find the precise word he needs. He experiences the “tip of the tongue” situation more often because he’s constantly changing languages, using them at ratios of 50:50 or 30:70 perhaps, while the monolingual person is 100% concentrated on just one language, so it’s not so difficult to come up with the more unusual words. Finally, there’s the matter of energy consumption. When you speak Catalan, you can’t switch off Spanish. You have to focus on one language and set aside the other. A monolingual person doesn’t have to do this. Bilingualism means devoting more resources and using more energy in this linguistic monitoring. It’s like when you go to England and you end up getting tired because of the effort of speaking English and your attempts to sideline Catalan and Spanish in order to speak English. Nevertheless, this outlay is only in terms of energy. It doesn’t use up neurones. In fact, quite the opposite happens.

What about the advantages of bilingualism?

Well we find that this linguistic obstacle course of managing two languages and switching the focus from one to the other is beneficial, and that it affects other brain structures and cognitive processes apart from language. We see that bilingual people can focus their attention better on stimuli, that they control attention better, have more grey matter and more neural connections in certain areas, and this means that they have a larger cognitive reserve when they are old. In bilingual people brain deterioration is slower. For example, we have seen studies showing that, among patients with Alzheimer’s disease, bilingual people come to the doctor complaining of symptoms later than monolingual people. This doesn’t mean they don’t have Alzheimer’s. In fact they show the same brain damage but they have compensatory strategies as a result of the obstacle course they’ve been managing for sixty years.

What are the practical applications of all these studies?

A better understanding of cortical representation of language can help us with a lot of things, for example, to decide whether to operate on a person or not. In the case of brain tumours we can know how the patient will end up, whether he or she will lose language or not. Or in bilingual patients who’ve had a stroke, we need to think about which language we should use for the rehabilitation. The one that’s least affected? Or the one that’s more affected? Or the one that’s more useful? These studies also help in language learning, to the extent that we can discover which techniques are best for language acquisition, or what predisposition each person has for languages. With small children we can find out which ones are more sensitive to phonological contrasts, and hence which children have more ability in learning languages, and so on.

Contemporary Museum of Calligraphy

Here’s another question people must always ask you: is it true that the earlier you start to learn a language the better?

The cliché says the earlier you start the better but this depends on certain other things. We know that sounds and accents should be learned very early. It is true that there is variation among individuals and that some people are good at capturing accents well but, in general, accent is picked up in the first year of life. Syntax should also be learned young but acquiring new words, for example, has no age limit. You can do this all your life. You’re learning new words in Catalan every day. This issue is always the cause of great controversy because, in Catalonia, we want the children to learn English, and the earlier the better, but we give them native speakers in the more advanced classes while the small children get non-native speakers! We need to give children teachers who are native speakers from the very beginning. This question always stirs people up and, every time I talk about it, I get complaints in emails from primary school teachers.

In Spain, your research has always been highly politicised.

It certainly has. When the Catalan radio stations phone me I know they want me to talk about the advantages of bilingualism and, in Madrid, they always ask me about the disadvantages … But, besides what goes on in the brain, bilingualism is a social decision. We decide whether to be bilingual or not, independently of what happens in the brain.

In the world in general bilingualism is the norm and monolingualism the exception.

Yes, monolingualism isn’t so common. In Europe it is relatively uncommon. Most European citizens speak more than one language. Another matter is whether you’ve been bilingual from the cradle. This isn’t so common, but there are a great many contacts between languages and this happens all around the world.

Alternatives to evolution

March 5th, 2014 No Comments

The challenges and new discoveries in brain research are the subject of «The Brain», the ICREA-CCCB debate which, over the coming four Thursdays, will make known the work of some of the country’s leading researchers in the neurosciences. The cycle begins with a lecture by Ricard Solé, ICREA research professor at the Pompeu Fabra University, who will give the lecture Brain(s): automatons, accidents and sinthetic evolution on 11 March about synthetic life and the possibilities now being opened up for shaping and finding alternatives to Darwinian evolution.

Ricard Solé

What can we understand by synthetic evolution?

We work with complex systems and synthetic biology is part of our research in which we examine how far it is possible to go in construction and design on the basis of biological components, and whether we can create some kind of system that might carry out computations or make decisions, systems that might learn and that can imitate and that would therefore be comparable with the brain or neuronal systems. In my department we inquire into what can be done and what can’t be done. Evolution has created a series of structures like the brain, which is a great innovation, but we are asking, “would there be alternatives?” or “is this the only possible solution?” If some day we manage to develop the technology that would make it possible to imitate something like the brain, with intelligence, awareness, cognition or empathy, would this system necessarily have to imitate life? Or are there other alternatives? Starting from here, we formulate the question on many different scales.

What is the role of the brain in your research?

We can’t create brains in the laboratory but we’re working with cells that are normally individualist and only know how to look for food, and we’re managing to get them to communicate and make decisions as a group, like ants, so they can learn and make decisions, et cetera. Evolution invented that but we have the chance to change the process and introduce into it things that were not envisaged in evolution. And synthetic biology is making us reconsider things that once seemed clear, for instance aging or death. We all believed that aging was an inevitable process, pure thermodynamics, but this is false. Aging can be stopped. In fact, evolution has brought us to this point because the natural way is to live long enough to reproduce and that’s that. However, in the laboratory we have found that you can manipulate the ends of chromosomes and put one of the aging enzymes out of action. Mice that live three times longer than the usual lifespan have been produced and others have been made to die young. We can therefore skip this law, this “design principle”. We wonder how far we can go with these possibilities and if there are any alternatives to aging, or if we can design systems wherein aging doesn’t have to be one of the basic rules. This generates more questions and makes us think that there are many such things that we have taken for granted but, now, we should perhaps be calling them into question.>

The brain, for example, works optimally in many regards but is a disaster in many others. It’s able to function at very low levels of metabolic outlay, and we scientists are unable to reproduce this. Yet there are many very inefficient things. The brain has been building on what there was before so, within the human brain, there is the brain of the reptile, the brain of the rat, and so on, and this creates a lot of conflicts in the way we think and when it comes to having stupid beliefs. If we want to construct a machine, is it important to bear that in mind? Or how important is the fact that we have been children? We learn the language in a process of acquiring knowledge that begins in early childhood and have seen that, maybe because certain things happen in that process, we need to be children. There are people who are working on “child” robots and perhaps the design of complex systems has to go through a process of growth.

In any case, yours is research without immediate practical results…

Yes, it’s pure theory. We’ve always been theoreticians and it’s only in the last few years that we’ve had a laboratory in which to carry out experiments. The goal of our work is to try to understand the origins of complexity and part of it is related with cognition, with how you learn, how you incorporate information, how you adapt to an external world with the ability to predict or being unable to predict. Time is very important for the human being and, for example, time clearly distinguishes us from any machine. You know that there’s a past and a future but machines live in the present. How can we do this, endow a machine with this? Our job is to raise such questions even if we are a long way from knowing the answers.

Nevertheless, we have some laboratory results. Imagine that we can get some bacteria to behave like ants, so they can learn and collectively resolve problems. We’re trying to re-create in the laboratory how cooperation appeared millions of years ago. If we can do this, we’ll be opening up interesting horizons. We’d be able to design cells that could go to tissue and do what we want it to do – reconstruct it, for example.


How do you work? With powerful computers? With simulators?

You can approach the problem in many ways, from mathematics, to making theoretical models in which you approach the question in a very general way, through to computers where you can bring about evolution in circuits and artificial machines using Darwinian evolution. In other words, we don’t design them in the same way as an engineer would consciously go about it, but by trying to prompt their re-creation in the way that nature has evolved. Part of our inspiration also comes from science fiction when we read works that were written in the 1940s and 1950s, before the information revolution began. There are some very diverting things from that period. For example, the robot that cleaned the house wasn’t a Roomba but a robot in human shape with a vacuum cleaner in its hand. However, going beyond that, some science fiction is very interesting and it really transcends present-day technology. Science fiction also speculated on the brain-machine interface that might enable the brain to expand using technology but, from what we know about the brain at present, I very much doubt that this would be feasible.