OHBM 2019 Talairach Lecture: Professor Riitta Hari

BY Jessica Turner

This year’s OHBM Talairach awardee, Professor Riitta Hari, has had a momentous impact in magnetoencephalography (MEG) research. A professor emerita and Academician of Science and member of the US National Academy of Sciences, she has led the Brain Research Unit of the Low Temperature Laboratory at Aalto University in Finland since 1982. Her work has been critical in understanding how MEG sheds light on brain activity, and how that dynamical activity contributes to cognitive functions including action observation.
Here, Jessica Turner found out about Riitta’s background, her current work with artists and the remarkable, undistorted, window into the brain offered by MEG.

Professor Riitta Hari

Jessica Turner (JT): If you were speaking to a non-scientist, how would you describe your research and what you do for a living?
Riitta Hari (RH): I’ve been emerita now for three years, but I would describe it as working in systems neuroscience, focusing on brain dynamics across a range of time scales.  The time scales of neurons and behaviors are very different, and how to relate them is a big part of the research.

JT: How did you get started in your research?
RH: I started using EEG in physiological studies and was trained as a clinical neurophysiologist, which means a physician who in the hospital tries to record various electrical signals from brain, muscles and nerves, to help with diagnosis of neurological and orthopedic patients. And there, of course, very small time lags make a big difference, and can be very informative.

JT: How did you get from clinical EEG to research?
RH: I started with research before clinical work. I was interested in understanding  how the human brain works, and thought I could get my PhD while I was still getting my training in medicine. I thought I would work with sensory responses in EEG, but then I landed almost by accident in MEG—magnetoencephalography, which has been my main working area for almost over 40 years. The reason was, I recorded slow EEG shifts which were easily distorted, for example by eye movements. But then I heard in the literature that maybe if you make magnetic recordings, eyes don’t produce any artifacts. I knew that some people here in Finland were recording magnetic fields of the human heart; so I contacted them, and we started to see if we could record magnetic fields from the human brain. It soon turned out that published paper, that led me to this idea of magnetic recordings, was totally wrong but I was hooked. And then I continued with this.

JT: You are a world expert in MEG, and most OHBM attendees are not as familiar with those methods as they may be with MRI; can you say something about MEG relative to EEG, in terms of its advantages?
RH: In many ways, MEG is like the other side of the coin – or rather, EEG and MEG are two sides of the same coin, they are both temporally very accurate measures that tell about the timecourses of synchronized neural populations’ activity.  But for MEG, the skull is totally transparent! It’s like the opposite method to transcranial magnetic stimulation—in TMS, you apply some magnetic pulses from outside the head, and it affects the brain. But here we have the activity in the brain, and our sensors that are outside; thus the physics of MEG is kind of inverse of that of TMS. But the important thing is that we get much less distorted signals because the skull does not distort.

JT: Your upcoming Talairach lecture is titled “Timing matters” –can you say something about the talk without giving away the punchline? Can you give us a teaser?
RH: Yeah, I think maybe the teaser would be that a very interesting feature of human brain function is that the brain is, at the same time, very accurate,and very sluggish. So we can discriminate some really tiny, tiny differences, like during directional hearing, we can find differences within the timescale of less than a tenth of millisecond. But then on the other hand, our percepts can be sluggish in the order of several hundreds of milliseconds.  We are predicting the future, but we are also lagging behind the physical events-. Sometimes we are ahead, and sometimes we are behind.

JT: What do you see as the most important developments in your field (however you would describe it) at the moment; or what do you see as the most urgent needs?
RH: In thinking about the developments that have already taken place, one is of course, the technical development, that they have built up these multichannel devices. It took some 15 years to go from single-channel devices to devices covering the whole scalp, and almost 20 years these large sensor arrays have been around. And then there's been some very important developments in artifact rejection, allowing MEG to be  used in patients, who are moving, or very small children. Of course, we are still expecting new developments in the instrumentation - that there will be devices that we could put closer to the brain. This is necessary because between the brain and our sensors there is too much space! If the sensor is attached to the scalp then the spatial resolution of MEG will be much improved.
I think it's extremely important that people working with different methods like with EEG and MEG, will be well aware of what is happening in the other field; because sometimes MEG people ignore what is happening in EEG and vice versa, or many fMRI people don't think about the timing. But things are improving a lot.  Even if we know that many parts of the brain are active at a certain time, or in a certain task, it doesn't tell us enough about brain function unless we also know the timing. One might even say that the brain is a timing machine in a way, because we predict the future on the basis of the past and the present. So timing is extremely central to brain function.

JT: OHBM is largely made up of trainees at many different levels. They look up to people like you and would like your advice. What advice would you like communicated to our large trainee audience?
RH: That’s an interesting question. Motivation is the key—Science should be and is fun, if you are working in an area you are interested in. Also, learn the methods well and early. And cultivate smart friends, so you have people to talk to.
An old Japanese poet from 1600, Matsuo Basho, said, “Do not seek the footsteps of the wise; seek what they sought.”  Try to see what has motivated the older scientists, rather than doing what they have done.
And also, if I may, try to form a solid sense of what you know, so you can recognize anomalies in your data, what doesn’t fit.  Sometimes the whole direction of science changes when something doesn’t fit.
Read old books, in addition to the new ones, because there you can learn a lot. You may realize how wrong good old scientists were when they wrote their book, as they did not known so much as at present but you can still appreciate their thinking..

JT: When you say “cultivate smart friends”, would you say that collaborations have been important to you?
Yes, that’s true. It’s really important to not work with assholes. It’s better to work with people you appreciate and enjoy talking to, because many new ideas come up when you’re talking about the topics you are interested in.

JT: What should the non-expert be wary about when reading about research in your field, particularly communication with the public and with press releases?
RH: I think it’s more or less similar to any brain imaging data and electrophysiology. think for the general audience, maybe the important thing is to emphasize that this kind of research is pretty technical. Many researchers thus may make mistakes and it is good to wait for confirmation.  I would say, don’t immediately trust the beautiful images and visualizations—they are very tempting, but it is really quite challenging to find out what is reliable.

JT: Any other pieces of advice?
RH: Well if you find this interesting: for the past three years, I have been working with the Department of Art here at our university. I’ve been trying to bridge between the understanding of neuroscience and how artists think, how people generate or produce art, and how artists view the world. There is a life outside of science and this is one interesting area, art.  People are very interested, I’ve gotten a good reception and have some interesting collaborations, but the gap is very big between art and neuroscience. During development each individual forms rigid habits of perception, and artists have to learn to break these automatized habits to see the world in new ways, Scientists need to be able to do that too.

JT: Thank you so much for your time!