LORETA Z Score Biofeedback

Today we are riding the crest of a wave of converging new neuroscience In the physics of source localization the forward solution is where a source inside a sphere determines the electrical potential on the surface as calculated using Maxwell's 1864 equations. In contrast, the inverse problem is where the sources are unknown and the location of the sources are estimated by measuring the electrical potential on the surface (Malmivuo and Plonsey, 1995). To solve the inverse equation one must apply physiological constraints such as used in cardiology in the early 1900s and quantitative EEG (QEEG) in the 1980s (Malmivuo and Plonsey, 1995). Low Resolution Electromagnetic Tomography (LORETA) uses physiological constraints related to the human electroencephalogram (EEG) including the use of distributed source smoothing (Pascual-Marqui et al, 1994). LORETA uses a 3D Laplacian spatial operator as a source smoothing constraint where simultaneously active sources distributed in space are used to solve the inverse equation. Importantly, the LORETA solution to the inverse problem was also linked to the standard co-registration used in all neuroimaging modalities including PET, SPEC and fMRI. The linkage to 7 mm cube electrical source volumes co-registered to the standard normative MRI allows for real-time millisecond biofeedback of electrical sources with a similar spatial resolution as fMRI and sufficient for larger volumes such as Brodmann areas that range from 1 to 6 square centimeters (Brodmann, 1909). High-speed computers are essential because the brain is organized in clusters of neurons called Modules and Hubs where groups of neurons are cross-frequency phase locked in re-enterant loops of bursting action potentials conducted by cortical white matter and temporally coordinated by the thalamus and brainstem-limbic systems These important brain dynamics are too fast for fMRI to measure directly. This is important because structure and function are linked in biology and functional localization in the brain e.g., visual cortex and blindness, deafness and temporal lobe damage, etc, when linked to the patient's symptoms aids in rendering a diagnosis and treatment for him or her. An advantage of LORETA EEG biofeedback is that one can target anatomical regions related to " loss of function " or " weak " function related to the patient's symptoms and complaints (Luria, 1973). This approach has been followed in both LORETA EEG biofeedback (Cannon et al, 2005; 2006) and with fMRI (de Charms, 2008).