Professor Zouridakis Talks about Brain Research in the Basque Country

Dr. George Zouridakis is serving as Visiting Professor at Ikerbasque Basque Foundation for Science, in the Basque Center on Cognition, Brain, and Language (BCBL - Spain). Zouridakis is professor and director of the Biomedical Imaging Lab at the University of Houston.

His research emphasis area is biomedical engineering and the interdisciplinary fields of computational and cognitive neuroscience.

Following is a transcript from recent media interviews in Spain.

What is your research field here and on what projects are you working?

In general, my research is focused on the interplay between information processing in the brain and the neurophysiological signals recorded outside of the head, like the electroencephalography (EEG) and magnetoencephalography (MEG). I am intrigued by how different brain areas communicate with one another to form brain connectivity networks. I am particularly interested is the so-called default mode network, which is activated when the brain “switches” between “goal-directed” and “default mode” activity after completion of a task.

Activation patterns of brain networks are of paramount importance in cognitive neuroscience, because they can be related to various cognitive states of a person, such as alertness, fatigue, and stress, they can differentiate, for example, monolinguals from bilinguals, and they can characterize clinical conditions such as dyslexia and traumatic brain injury. In other words, they constitute unique biomarkers.

From the clinical point of view, biomarkers can play a significant role in the diagnosis and treatment of patients, and in assessing disease progression and treatment effectiveness.

What are the neuroimaging techniques used in neuroscience? What is the aim of each one of them?

In general, through neuroimaging we seek to characterize brain activation, that is, elucidate how the electrophysiological, biochemical, and hemodynamic events observed in the neural tissues correlate with specific brain functions, such as memory, language, learning, and perception. Each neuroimaging technique is designed to detect a particular aspect of activation. EEG, for instance, measures changes in the electrical activity of neurons and MEG the corresponding magnetic aspects of it. MRI is thought to represent oxygen level changes in tissues due to blood flow variations while PET detects changes in blood perfusion by estimating the relative concentration of radiolabeled compounds, such as water and glucose. NIRS measures oxygen concentration and hemoglobin content in the cortex by analyzing the properties of light scattered through the brain tissues.

All of these techniques provide complementary information about physical events that relate, either directly or indirectly, to a particular brain function.

Your main field of expertise is MEG. Please describe how this technique has evolved in the last few years.

The first MEG recording was obtained with a single channel device in 1968, marking the beginning of a new era in brain research. In the early 1980s, machines with a few channels started to appear, and by the mid-1990s, devices with more than 100 channels became commercially available. Today, typical MEG machines provide more that 300 channels, while the latest prototypes even combine MEG with MRI.

A similar progression has been followed by analysis techniques: due to the limitation of computational resources, early methods employed simplified mathematical models, focusing mostly on identifying the brain areas associated with certain brain functions. Today, however, several sophisticated methodologies allow the study of complex behavioral functions through the analysis of activation patterns of the whole brain simultaneously.

How would you describe BCBL´s equipment in neuroimaging?

Even though BCBL is a relatively new research center, under the leadership of Dr. Carreiras it already enjoys word recognition for the unique facilities and research opportunities it provides, as well as the quality of publications and expertise of the research team.

Why is neuroimaging important?

There are several neuroimaging techniques available today that can show brain anatomy in fine detail, but most importantly, they can visualize brain function in living humans, often in real time.

Thanks to recent technological developments in hardware, and contributions from advanced mathematics and innovative computer algorithms, we can now study how the healthy brain works, and the way that various disease states affect brain function at the molecular, cellular, and system levels.

On the clinical side, one may argue that neuroimaging has resulted in better patient diagnosis, more efficient and less invasive treatment procedures, shorter hospital stay, and improved overall outcome.

How has neuroimaging changed brain research?

In the last few years, we have been offered an unprecedented opportunity to expand our understanding of complex human behavior and the advanced mechanisms that underlie normal brain function. Neuroimaging is being used to study autism, dyslexia, attention deficit disorder, schizophrenia, depression and a variety of other neurological, psychiatric, and developmental conditions in an attempt to comprehend and possibly remedy their effects.

Imaging technology, experimental design, and data analysis techniques are all evolving so fast that we can now go beyond the early quests of linking brain areas to specific brain functions. We have now embarked on a journey to unravel the relationship between the human brain and the mind.