Electrophysiology of Attention

Abstract

This chapter describes how auditory and visual attention can be studied using event‐related potentials (ERPs). In audition, the mismatch negativity (MMN), a component of the ERP elicited by any discriminable change in an auditory stimulus stream, provides an excellent index of attention‐independent auditory processing: MMN data convincingly show that accurate central sound representations emerge even in the absence of attention. ERPs also index the two principal brain mechanisms that are involved in involuntary attention switch to unattended auditory stimulation, with the N1 component being related to attention switch to sound onset and the MMN as well as P3a components reflecting attention switch to sound change. Furthermore, the newly discovered reorienting negativity (RON) component seems to be related to the focusing of attention to task‐relevant aspects of stimulation following distraction. The processing negativity (PN), in turn, provides an on‐line index of auditory selective attention. In the visual modality, several ERP components are modulated by selective attention, the earliest effect being caused by visuo‐spatial attention which even affected the P1 generated in extrastriate cortex with a onset latency of about 70 ms post‐stimulus. The subsequent N1 component may also tap into attentional functions and, in addition, slow, PN‐type of selection negativities and positivities can be obtained, depending on the selection criteria (e.g., color or form) and the attentional demands.

Distraction and facilitation—two faces of the same coin?

“…However, it should be noted that new or salient events elicit an orienting response (Sokolov, 1963) and may activate two separate processes, an attention switch and an increase in unspecific arousal (Näätänen, 1992). Increased arousal can facilitate sensory and motor functions, their central integration, and the available capacity (e.g., Kahneman, 1973).…”

“…could improve perfonnance (Näätänen, 1992). Furthermore, environmental novel sounds are motivationally significant stimuli.…”

“…The novel-related facilitation effect could be explained in the context of arousal. New and unexpected events can elicit the orienting response (Näätänen, 1992;Sokolov, 1963). Whereas the attentional component of the orienting response is usually emphasized to explain distraction, the arousal component has often been neglected.…”

“…It can be explained within the classical involuntary attention account according to which deviant or novel sounds elicit a call for attention. As a consequence, less resources are available for performing the primary task, resulting in impaired performance (e.g., Escera et al, 2000;Näätänen, 1992). It is interesting, however, that the pattern of RTs in the uninformative condition reveals that neither novels nor deviants cause prolonged RTs relative to standards.…”

“…Nevertheless, distractor sounds result in behavioral impairment usually interpreted as distraction (e.g., Schröger & Wolff, 1998). The brain's automatic detection of novelty or deviancy is reflected by the NI and MMN components of the event-related potential (for a review, see Alho, 1995;Duncan et al, 2009;Garrido, Kilner, Stephan, & Friston, 2009;Kujala, Tervaniemi, & Schröger, 2007;Näätänen, 1992). Nl/MMN can be followed by an attentional orienting toward these distractors, which is reflected by the P3a or novelty P3 component (for a review, see Escera, Alho, Schröger, & Winkler, 2000;Friedman, Cycowicz, & Gaeta, 2001;Polich & Criado, 2006).…”