Source reconstruction of sensory and cognitive evoked potentials

Abstract

Cortical activity reflected in auditory-evoked potentials (AEPs) is often evaluated using only a small subset of all the recorded data. Conclusions based on this approach can be misleading, with no utility in identifying the underlying neural generators of the scalp recorded activity. Techniques that make use of all of the AEP data range from relatively simple methods, such as global field power, to more advanced approaches including independent components analysis (ICA), dipole modeling, and current density reconstruction. The objective of this presentation is to describe analysis of the component-structure of AEPs using these advanced techniques. Results of the ICA analysis will be used to generate spatial filters characterizing the specific scalp distribution associated with each ICA pattern. The cortical origin of each ICA scalp distribution will then be determined using current density reconstruction. The analysis will be applied to standard AEPs as well as the mismatch negativity in normal hearing and cochlear implant users. The results will demonstrate the unique suitability of neuroimaging based on AEPs for understanding the effects of cochlear implant use on cortical activity associated with cognitive processing in children and in adults.