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http://hdl.handle.net/1956/2509
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| Tittel: | Electrophysiological and Hemodynamic Correlates of Expectancy in Target Processing |
| Forfattere: | Eichele, Tom |
| Dato: | 20-Nov-2007 |
| Forlag: | The University of Bergen |
| Sammendrag: | Identifying patterns of recurrent events is central to human perception, cognition
and behavior. By extracting patterns from the environment, individuals can make
efficient predictions about future events. By and large, the detection of these
contingencies is the core faculty to respond to, interact with, and ultimately make
sense of the world. The aim of this thesis was to investigate how the brain treats
temporal patterns and generates expectancies from regular event sequences.
A variant of an auditory oddball paradigm was developed in which predictability
was modulated with sequences of random and regular targets. In order to assess
both the temporal and spatial implementation of these effects, single trial event
related potentials and functional magnetic resonance imaging were employed.
In the first paper, the effect of predictability on brain activity was studied with
single trial ERPs, yielding sigmoid-shaped learning curves on CNV, N2 and P3.
The second paper described a method for integration of single-trial ERP with
fMRI data, and reported three spatiotemporal activation patterns during the P2,
N2, and P3 in addition to the generic activation elicited by target stimuli. An
additional modulation beginning during the N1 was extracted in the third paper
that employed a method for parallel unmixing of concurrent EEG-fMRI data.
The results of the thesis have implications for the understanding of ERP
components, the concepts of how a standard representation is formed and how
context is updated need to take into account the effects of predictability observed
here. Furthermore, the thesis presents straightforward methods for single-trial
ERP, and concurrent EEG-fMRI analysis that afford comprehensive spatiotemporal
mapping of event-related processes in the brain. |
| URI: | http://hdl.handle.net/1956/2509 |
| ISBN: | 978-82-308-0452-0 (print version) |
| Vises i samlingene: | Department of Biological and Medical Psychology
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