Electrophysiological correlates of complex attentional selection

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Title: Electrophysiological correlates of complex attentional selection
Authors: Schöne, Benjamin
Thesis advisor: Prof. Dr. Thomas Gruber
Thesis referee: Prof. Dr. Roman Osinsky
Abstract: Attention is one of the pivotal research subjects in psychological science. Its major function is to select relevant information from the sensory streams and suppress distracting information. As the capacity of the brain is limited, a task-oriented selection of input is a crucial feature of cognition, promoting efficient behavior. Early approaches of attentional systems thus focused on this to a high degree passive perceptual filtering aspect of attention. Most influential is for example Broadbent's model (1958), assuming that relevant information is filtered out during early stages of the sensory stream, while ignored information is completely lost. This theory was quickly complemented by Deutsch and Deutsch (1963) with a mechanism for late selection, showing that information can be semantically processed without awareness and later selected according to situational demands. As a hybrid model of early and late selection, Lavie's load theory (1994) addressed two main questions arising from the initial approaches: At which stage of the sensory stream does selection occur and to which extent is ignored information processed. Lavie concluded that under high information load, irrelevant information is suppressed at early stages, whereas under low load, when the brain's capacity is not exhausted, it is processed in depth. Although widely accepted and believed to correspond to the functional properties of cognitive processes, even load-dependent theories do not account for all kinds of attentional phenomena. Especially the complex interactions of affect, memory as well as executive functions, which constitute the variety of attentional processes, make it difficult to develop an integrative framework of attention. This is particularly the case, since conventional approaches to attention still seem to be under the intermediate immersion of the attention solely as a perceptual filter. Inspired by more holistic and integrative approaches by Nelson Cowan and Eric Kandel, who regard attention as a constructive, even creative process this dissertation aims to illuminate the phenomenon of attention from several perspectives. The purpose is to gain insights, which go beyond the results obtained by conventional or so to say conservative 6 paradigms. Four electrophysiological studies are applied to investigate attentional mechanisms and structure along the visual information stream. Study 1 investigates the electrophysiological correlates (ERPs) of automatic allocation gain, reflected by the P1 component, in response to highly salient stimuli, making a case for motivational relevance in attentional processing. Study 2 takes a closer look at said gain processes, investigating frontal alpha asymmetries, which index modulation of striatal reward encoding. Further top-down modulations are the research subject of Study 3, which puts declarative memory into focus. Specifically, the effects of functional network properties of long-term memory encoding self-relevant information on attentional gain mechanism are investigated. As a result, self-referential processing is based on automatic retrieval of personal information as opposed to the processing of unknown persons, which requires voluntary, that is, strategic, attention-demanding processing as indexed by the N170 and the N400 component, respectively. Study 4 investigated the neural efficiency gains related to meditation practice combining multiple object tracking with steady-state visually evoked potentials. The results shed new light on the interaction of attentional focus and visual short- term memory, showing that enhanced distractor resistance profits from attentional de- automatization, thereby increasing capacity limits of visual short-term memory. In the general discussion of this thesis, Cowan's integrated framework of attention provides a reference for evaluating and relating the results in s structured manner in order to overcome the limitations of the perceptual filter approach. An updated version of Cowan’s framework is furthermore proposed, incorporating the new empirical data. Last but not least, new questions, concepts and predictions arising from the model are discussed.
URL: https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2018050817149
Subject Keywords: Attention; Memory
Issue Date: 8-May-2018
Type of publication: Dissertation oder Habilitation [doctoralThesis]
Appears in Collections:FB08 - E-Dissertationen

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