Estimating Distributed Representations of Evoked Responses and Oscillatory Brain Activity

This chapter discusses the relative advantages and disadvantages of distributed representations of source activity. After covering some theoretical considerations, it discusses how to apply the technique to event related fields and oscillatory activity in practice. The chapter makes the following points: (i) distributed representations of electrophysiological activity are typically done using current estimates and beam-forming techniques; (ii) distributed representations allow for spatial normalization and group averages; (iii) minimization constraints are applied when calculating distributed current estimates resulting in spatially smooth solutions; (iv) both event-related responses and oscillatory brain activity can be modeled by distributed current estimates; and (v) beam-forming approaches are best suited for longer lasting brain responses such as modulations of oscillatory activity.