A Programmable Laboratory Testbed in Support of Evaluation of Functional Brain Activation

• Near infrared spectroscopy (NIRS) and electroencephalography (EEG) • Complementary sensing technologies with desirable attributes: • Inherently compact form factor • Sensitivity to hemodynamic (NIRS) and bioelectric (EEG) phenomenologies associated with neuroactivation. • BUT, experimental phantom-based systems, analogous to those routinely used to evaluate structural imaging methods, currently are unavailable • Important for the development of functional imaging applications based on NIRS or EEG, or both in combination • Would be used to quantitatively assess the accuracy of derived functional information. • To address this need, we have undertaken a technology integration effort with the following aims: • Ability to initiate and recover complex macroscopic behaviors that, in general, are not directly observable • Implement the modeled behavior in a longitudinally stable, anthropomorphic head form that supports translation from laboratory-based to subject-based studies. • The first aim is addressed by manufacturing programmable dynamic phantoms for hemodynamic and bioelectric studies • Device has an anthropomorphic form similar to one we reported several years ago [1], but: • Important added feature is a hermitically sealed, conducting brain space that is stabilized against biological degradation. • Brain compartment contains programmable source elements—electrochromic cells (ECC) and electric dipoles—that can be precisely controlled electronically. • Manipulation of the voltage across ECC leads changes its opacity, as a way of mimicking time-varying blood volume or oxygen saturation. • The dipoles can be used similarly to model time-varying EEG sources. • The second objective is accomplished by employing the same sensing devices, headgear, and analysis resources used in humanor animal-subject studies to explore the programmable validating environment, or testbed.