John Clarke is Professor of the Graduate School in the Physics Department at the University of California, Berkeley. He received his BA in 1964 and MA and Ph.D in 1968, all from the University of Cambridge, England. He became a postdoctoral scholar at UC Berkeley in 1968, and has been a faculty member there since 1969.

Currently, he and his group are using SQUIDs (Superconducting QUantum Interference Devices) to obtain magnetic resonance images in magnetic fields four orders of magnitude lower than those used in conventional MRI machines. Their other research interests include the use of SQUIDs as amplifiers at frequencies around 1 GHz in a search for the axion, a candidate for cold dark matter, and understanding the origin of the ubiquitous “flux noise” that both gives rise to decoherence in superconducting qubits and limits the low frequency performance of SQUIDs.

Amongst his awards and honors he is a Fellow of the Royal Society, from which he received the Hughes Medal, a Foreign Associate of the National Academy of Sciences, from which he received the Comstock Prize in Physics, and a Fellow of the American Academy of Arts and Sciences. He received UC Berkeley’s Distinguished Teaching Award in 1983.

Ultralow field magnetic resonance imaging (ULF MRI) is performed in fields of typically 130 microtesla, four orders of magnitude lower than in conventional MRI. Imaging at such low fields is made possible first, by prepolarizing the protons with a much higher magnetic field and second, by detecting the signal from the precessing protons with a SQUID (Superconducting QUantum Interference Device). The high longitudinal relaxation time T₁-contrast intrinsic to ULF can be enhanced using a combination of inversion recovery and multiple echo sequences, as illustrated by in vivo images of the human brain showing brain tissue, blood, cerebrospinal fluid (CSF) and scalp fat. A study of 35 patients reveals a significant T₁-contrast between ex vivo normal prostate tissue and tumor tissue. Values of T₁r and ULF T₁ and T₂ in protein gels, post mortem pig brain and in vivo human brain reveal intriguing distinctions. In other institutions, an important development is the use of multiple SQUID systems to integrate ULF MRI with magnetoencephalography (MEG), improving both the co-registration of equivalent current dipoles with brain structure and the signal-to-noise ratio of the ULF-MRI signals. A portable ULF-MRI system, operated without a metallic shield, has been demonstrated. Efforts are in progress to perform neuronal current imaging by observing the shift of the ULF-MRI frequency by the magnetic fields generated by the currents, and to map the conductivity of the brain by imaging externally injected currents. Methods to enhance the signal-to-noise ratio of ULF-MRI signals and thus improve the spatial resolution and reduce the imaging time are discussed. In addition to ongoing studies, other potential clinical applications of ULF MRI include imagingcancer without the need for a contrast agent and imaging traumatic brain injury (TBI) caused by, for example, stroke, traffic accidents, high impact sports and combat-related explosions.

1983 Graduate Shinshu University, School of Medicine
1988-1989 Research fellow, Division of Neurosurgery, The Hospital for Sick Children
1989-1994 EEG Fellow, EEG & Clinical Neurophysiology, Laboratory, The Hospital for Sick Children
1994 – 2008 Assistant Professor, Department of Pediatrics, University of Toronto
1997 – present Director of Operations EEG & Clinical Neurophysiology and Epilepsy Monitoring Unit (EMU)
2008- present Associate professor, Department of Pediatrics, University of Toronto

MEG has been applied for epilepsy since 1985. The interictal epileptiform discharges were localized as spike dipoles/ spike sources on MRI by MEG. When the patient presents with focal onset seizures due to brain lesion, MEG often succeeds to localize asymmetric spike dipoles surrounding the lesion. The respective surgery of lesion and the clustered dipoles in theadjacent cortex achieves the seizure freedom. Recently MRI improves the spatial resolution to demonstrate epileptogenic neuronal migration disorders, such as focal cortical dysplasia (FCD). MEG favors to demonstrate the epileptogenic FCD on the brain surface. The complete resection of FCD cures the intractable seizures. Furthermore, MRI can identify the small and deep FCD at the bottom of sulcus (FCDB). FCDB frequently provoked the focal onset seizures which becomes refractory to multiple anti-epileptic medications despite of the small epileptogenic zone. The dipole analysis on MEG often fails to recognize the small and deep epileptic FCDB, since MEG needs at least 3cm2 neuronal bundle. FCDB is located at the bottom of the deep sulcus with closed field effects that can obscure the dipolar magnetic field. Then we have to develop advanced methods for MEG to improve the localization of various types of the epileptogenic zone. Furthermore, we are challenging patient with drug-resistant epilepsy with MRI invisible epileptogenic lesion. MEG wave forms from intracerebral epileptic discharges have millions of neurophysiological information. This presentation will present current and future collaborations between biomagnetism and epilepsy surgery for the improvement of diagnosis and treatment of epilepsy.

Lauri Parkkonen is Associate Professor (Medical Imaging) and director of Aalto Brain Center, Aalto University, Finland. His background is in physics and neuroscience, and he works at the intersection of neuroscience and neurotechnology by developing instrumentation and analysis methods for brain research as well as by applying these methods to study neural mechanisms of sensory processing, conscious perception, attention and recently also of social interaction.
He employs and develops primarily magneto¬encephalography as the brain measurement method and combines that with advanced signal-processing techniques, including real-time analysis that allows providing brain-activity-based feedback to the subject. He has also contributed to the design of commercial MEG systems at Neuromag Ltd (later Elekta Oy), to measuring and modeling neuromagnetic signals at the level of single cells and circuits, and to combining ultra-low-field MRI and MEG in the same device. He recently received a grant from European Research Council for developing a novel high-resolution MEG approach based on optically-pumped magnetometers.

MEG instrumentation and analysis approaches have developed remarkably during the almost 50-year-long history of MEG. The field has grown from single-channel measurements of alpha oscillations and evoked responses to e.g. assessing functional connectivity between brain regions and decoding subjective content of the mind. Yet, MEG still holds promise for further expansion in the way it can be applied in cognitive neuroscience and clinical practice. In this talk, I will discuss some of the current limits and future prospects of MEG. I will address instrumentation-relatedpotential and how that could change the way we can monitor cortical processing with MEG. I will also discuss and show examples on how recent progress in analysis approaches has enabled“closed-loop” experiments and successful use of contiguous naturalistic stimuli such as speech, music and movies in MEG. As an extreme along that line, I will describe why and how we study interacting subjects using a hyperscanning set-up comprising two interconnected MEG systems.

David Poeppel is a Professor of Psychology and Neural Science at NYU. From 2014 on, he is also the Director of the Neuroscience Department of the new Max-Planck-Institute in Frankfurt, Germany. Trained at MIT in cognitive science, linguistics, and neuroscience, Poeppel did his post-doctoral training at the University of California San Francisco, where he focused on functional brain imaging. Until 2008, he was a professor at the University of Maryland College Park, where he worked in the Cognitive Neuroscience of Language laboratory. He has been a Fellow at the Wissenschaftskolleg (Institute for Advanced Studies Berlin), the American Academy Berlin, and a guest professor at many institutions. He is a Fellow of the American Association for the Advancement of Science.

In the last twenty-five years, substantive progress has been made on the "where-is-language? question. Ever-finer maps of the functional anatomy underpinning language processing, based principally on different imaging techniques, reveal a widely distributed, bilateral arrangement of regions that, collectively, support the various functions that constitute language comprehension and production. Electrophysiological data from MEG, EEG, and ECoG have contributed in numerous ways to these map making endeavors. More importantly, however, research at the intersection of language and electrophysiology continues to provide significant insight into how? questions - an area of investigation in which more progress is possible. I discuss recent experiments on speech perception and language comprehension that aim to illuminate some of the neural mechanisms that are necessary for this foundational human ability

György Buzsáki is Biggs Professor of Neuroscience and Neurology at New York University. His primary interests are mechanisms of memory, sleep and associated diseases. His main focus is “neural syntax”, i.e., how segmentation of neural information is organized by the numerous brain rhythms to support cognitive functions. His recognition of the importance hierarchical organization of simultaneous oscillations of different frequencies and cross-frequency coupling has opened up tremendous opportunities for the dissection of cognitive mechanisms in health and disease.
 

His most influential work, the two-stage model of memory trace consolidation, demonstrates how the neocortex-mediated information during learning transiently modifies hippocampal networks, followed by reactivation and consolidation of these memory traces during sleep. He identified Sharp wave Ripples, a biomarker for transferring hippocampal information to neocortex. With more than 340 papers published on these topics, he is among the top 1% most-cited neuroscientists.
 

Buzsáki is a Fellow of the American Association for the Advancement of Science and the Academiae Europaeae and an honorary member of the Hungarian Academy of Sciences, and he sits on the editorial boards of several leading neuroscience journals, including Science and Neuron, and have received honoris causa from Université Aix-Marseille, France and University of Kaposvar, Hungary. He is a co-recipient of the 2011 Brain Prize.
(Book: G. Buzsáki, Rhythms of the Brain, Oxford University Press, 2006)