The clinical circumstance of invasive electrode implantation for the purposes of mapping function and pathology in patients with intractable focal epilepsy provides an unparalleled access to human brain physiology. The comprehensive epilepsy center at Northwell Health performs approximately 50-75 epilepsy surgery procedures annually involving implantation of electrodes for seizure monitoring and neurostimulation, extraoperative functional electrical stimulation mapping and therapeutic removal of epileptic brain tissue by surgical resection or ablation. Our lab uses this as an opportunity to study properties of brain networks, cognitive neurophysiology, validation of noninvasive neuroimaging with invasive electrophysiology and the effects of cortical stimulation on cognition and behavior. In this capacity, our lab is uniquely situated with the access to carry out research involving some of the most direct observations of in vivo human brain physiology.
One focus of the lab involves intraindividual, multimodal comparisons of networks using noninvasive intrinsic functional connectivity analysis applied to MRI and invasive electrocorticography. We have shown consistent intraindividual correspondence of network measures. Furthermore, we have developed databases of patients who have undergone invasive electrode monitoring with multiple intraindividual measures of brain connectivity including DTI, resting fMRI, electrocorticography, and cortico-cortical evoked potentials. We have also collected and archived data with regard to localization of functional areas using electrical stimulation mapping and task-related electrocorticography/fMRI as well as clinical measures including localization of the seizure onset zones, extent of resection and surgical outcome. We believe that these datasets will not only provide a more detailed understanding of brain networks, but because epilepsy is a network disease, these studies may ultimately improve epilepsy surgery outcome.
Another area of interest involves the neurophysiological basis of perception, cognition and action. With such direct access to human electrophysiology, we have studied the neurophysiological basis of a number of cognitive phenomena including language, visual object identification, attention, memory and motor planning. Furthermore, with direct cortical stimulation, we have begun to unravel how neuromodulation may be used to improve these various aspects of cognitive function.
The Laboratory for Multimodal Human Brain Mapping uses multiple methods for measuring brain structure and function to advance our understanding of human brain function and the treatment of epilepsy. The methods used include magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI), diffusion tensor imaging (DTI), electrocorticography (ECoG), and direct electrical cortical stimulation. The main goals of the lab are the following:
Successfully treating epilepsy requires understanding what regions of the brain are responsible for seizure activity and what regions are critical to cognitive functions such as language and memory. fMRI is a promising method for doing this since it can non-invasively measure the function of the entire brain with millimeter spatial resolution. The lab is investigating the utility of fMRI for identifying regions involved in language function and for identifying networks of areas responsible for epileptic activity.
As our understanding of epilepsy has grown, it has become increasingly clear that epilepsy is often caused by abnormal interactions between different parts of the brain. In other words epilepsy is often caused by a pathological network rather than a single epileptogenic area. The lab researches the use of fMRI, DTI, ECoG, and cortical stimulation for identifying these pathological networks and is attempting to uncover how their interactions produce seizures.
Different measures of human brain function have complementary strengths and weaknesses. For example, in contrast to ECoG, fMRI provides much more complete coverage of the entire brain but has much lower temporal resolution. Consequently, understanding the function of the human brain in much detail requires combining the findings from these different measures. However, doing so is complicated by the fact that the relationship between these measures is somewhat ambiguous (e.g., activity measured by ECoG might be invisible to fMRI). By obtaining these multiple measures of brain function in the same individuals, we are able to better understand how these measures relate and what inferences can be made from each measure alone.
The neuronal basis for visual and auditory perception, language, memory, motor function and attention are studied using invasive electrodes in patients undergoing seizure monitoring for epilepsy surgery. Results from fMRI, EEG and cortical stimulation mapping are used to define areas and networks of areas involved in physiological function.
Jose Herrero, PhD
Simon Khuvis, BSE
Erin Yeagle, BA
Rafael Malach, PhD
Charles E. Schroeder, PhD
Michael Milham, MD, PhD
Cameron Craddock, PhD
Fred Lado, MD, PhD
Elana Zion-Golumbic, PhD
Stephan Bickel, MD, PhD
Manuel Mercier, PhD
Corey J. Keller, PhD
Lucia Melloni, PhD
Ido Davidesco, PhD
University of Rochester, Rochester, NY
Field of study: Biology, Neuroscience
Albert Einstein College of Medicine, Bronx, NY
Field of study: Medicine/Neuroscience