Neural Mechanisms of Intermodal Sustained Selective Attention with Concurrently Presented Auditory and Visual Stimuli

We investigated intermodal attention effects on the auditory steady-state response (ASSR) and the steady-state visual evoked potential (SSVEP). For this purpose, 40-Hz amplitude-modulated tones and a stream of flickering (7.5 Hz) random letters were presented concurrently. By means of an auditory or visual target detection task, participants’ attention was directed to the respective modality for several seconds. Attention to the auditory stream led to a significant enhancement of the ASSR compared to when the visual stream was attended. This attentional modulation was located mainly in the right superior temporal gyrus. Vice versa, attention to the visual stream especially increased the second harmonic response of the SSVEP. This modulation was focused in the inferior occipital and lateral occipitotemporal gyrus of both hemispheres. To the best of our knowledge, this is the first demonstration of amplitude modulation of the ASSR and the SSVEP by intermodal sustained attention. Our results open a new avenue of research to understand the basic neural mechanisms of intermodal attention in the human brain

"Akademische" Zeitgeschichte - Texte und Kontexte: Vorwort

Die Deutung der jüngeren und jüngsten Vergangenheit liegt nicht allein in der Hand professioneller Zeithistorikerinnen und Zeithistoriker, sondern ist ein hart umkämpftes Feld mit verschiedensten Akteuren. Das vorliegende Heft widmet sich diesem breiteren Feld der "populären" Geschichtsschreibung aus unterschiedlichen Perspektiven. Welche Rolle spielt die "akademische" Zeitgeschichte nun bei der Konstituierung von Geschichtsbildern und Geschichtserzählungen? "Akademisch" mag wie ein abwertendes Signum klingen - unverständlich, im System Wissenschaft verfangen, vorbei am Publikum -, während es für den praktizierenden Akademiker eine Quelle seines Berufsethos sein dürfte (oder vielleicht der letzte Rettungsanker der Selbstlegitimierung). Strittig bleibt indes, was das "Fachwissenschaftliche" genau ausmacht: Sind es bestimmte Mindeststandards, die ein Geschichtswerk erfüllen muss, um als „wissenschaftlich“ anerkannt zu werden, oder ist die "akademische" Geschichtsschreibung im Wesentlichen durch eine (nicht allein fachspezifische) Forschungspraxis gekennzeichnet, die an strukturelle Bedingungen von Drittmittel- und "Exzellenz"-Projekten und akademische Moden gebunden ist sowie zu guter Letzt als "Abschlussbericht" in Darstellung überführt werden muss

Automatic detection of lexical change: an auditory event-related potential study

We investigated the detection of rare task-irrelevant changes in the lexical status of speech stimuli. Participants performed a non-linguistic task on word and pseudoword stimuli that occurred, in separate conditions, rarely or frequently. Task performance for pseudowords was deteriorated relative to words, suggesting unintentional lexical analysis. Furthermore, rare word and pseudoword changes had a similar effect on the event-related potentials, starting as early as 165 ms. This is the first demonstration of the automatic detection of change in lexical status that is not based on a co-occurring acoustic change. We propose that, following lexical analysis of the incoming stimuli, a mental representation of the lexical regularity is formed and used as a template against which lexical change can be detected. (C) 2007 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins

The N1-suppression effect for self-initiated sounds is independent of attention

<p>Abstract</p> <p>Background</p> <p>If we initiate a sound by our own motor behavior, the N1 component of the auditory event-related brain potential (ERP) that the sound elicits is attenuated compared to the N1 elicited by the same sound when it is initiated externally. It has been suggested that this N1 suppression results from an internal predictive mechanism that is in the service of discriminating the sensory consequences of one’s own actions from other sensory input. As the N1-suppression effect is becoming a popular approach to investigate predictive processing in cognitive and social neuroscience, it is important to exclude an alternative interpretation not related to prediction. According to the attentional account, the N1 suppression is due to a difference in the allocation of attention between self- and externally-initiated sounds. To test this hypothesis, we manipulated the allocation of attention to the sounds in different blocks: Attention was directed either to the sounds, to the own motor acts or to visual stimuli. If attention causes the N1-suppression effect, then manipulating attention should affect the effect for self-initiated sounds.</p> <p>Results</p> <p>We found N1 suppression in all conditions. The N1 per se was affected by attention, but there was no interaction between attention and self-initiation effects. This implies that self-initiation N1 effects are not caused by attention.</p> <p>Conclusions</p> <p>The present results support the assumption that the N1-suppression effect for self-initiated sounds indicates the operation of an internal predictive mechanism. Furthermore, while attention had an influence on the N1a, N1b, and N1c components, the N1-suppression effect was confined to the N1b and N1c subcomponents suggesting that the major contribution to the auditory N1-suppression effect is circumscribed to late N1 components.</p