The Center for Neuromagnetism
The Center for Neuromagnetism at the Department of Physiology and Neuroscience, New York University School of Medicine performs noninvasive functional brain imaging using magnetoencephalography (MEG). When MEG information is combined with structural imaging such as MRI, it is called magnetic source imaging (MSI).
This is a technique that measures the very small magnetic fields produced by the brain´s electrical current flow that generates synaptic and intrinsic neuronal activity. This method records brain activity with uniquely high spatial and temporal resolution. Our research encompasses both basic and clinical studies. We are interested in examining the spatial and temporal underpinnings of brain function during cognitive processes in different functional states (for example; sleeping, listening, watching a movie, relaxed with the eyes closed or open). The clinical studies examine changes in these processes in persons diagnosed with neurological or psychiatric disorders.
Several functional imaging techniques are now available which provide the possibility to study human brain function in a non-invasive manner. MEG is one such functional imaging technique, which, in addition to being truly non-invasive allows the localization of neuronal electrical activity, within the brain with mm accuracy and fast time resolution (~1 msec).
MEG recordings are obtained from the sitting position with the head surrounded by a helmet like recording sensor array as shown in the picture. This arrangement allows the sensors to be close to the head surface. The recording array consisting of a superconductive quantum interference sensors system (SQUIDS) fed by the recording coils. The MEG system is located in a magnetically shielded room and consists, in addition to the MEG devise, of a set of visual, tactile and sound stimulation systems.
The magnetic field generated by intracellular current flow along individual neurons is extremely small, too small to be detected outside the head. Thus co-activation of several thousand neurons are required to generate the field measured by the MEG. The brain magnetic fields being measured by the MEG are in the range of 50-1000 femtotesla (fT), that is about one billion times smaller than the earth's magnetic field. The MEG technology is actually supported by quite sophisticated technology with instrumentation sensitive enough to detect these weak signals, while simultaneously discriminating against interference from strong signals arising from the environment.