Episodic Memory, Theta-Activity and Schizophrenia
Doidge, Amie
Date: 15 May 2018
Publisher
University of Exeter
Degree Title
DClinPsy
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Abstract
People with schizophrenia are known to have difficulties with episodic
memory (EM). The purpose of this investigation was to examine the relationship
between theta-power and: i) behavioural measures of EM performance, ii) event-
related potential (ERP) indices of recollection and, iii) measures of schizophrenia
symptomatology. ...
People with schizophrenia are known to have difficulties with episodic
memory (EM). The purpose of this investigation was to examine the relationship
between theta-power and: i) behavioural measures of EM performance, ii) event-
related potential (ERP) indices of recollection and, iii) measures of schizophrenia
symptomatology. In doing so, the aim was to gain a better understanding of the
basic neural mechanisms that contribute to successful EM performance, and how
these may differ for people with schizophrenia. The present investigation adopted
an endophenotypic approach and collected measures of schizotypy from student
participants to minimise patient factors that can confound interpretations. Fifty-
four participants were asked to complete a reality-monitoring exclusion EM
paradigm whilst electroencephalogram (EEG) data were collected. Measures of
theta-power and ERPs were time-locked to words presented during the retrieval
phase. There was a significant positive correlation between theta-power over Fz
between 600-1000ms post-stimulus presentation and estimates of recollection in
the imagine condition as well as a significant negative correlation between these
measures of theta-power for perceive items and ERP indices of recollection for
imagine items. There was also a significant positive correlation between
measures of frontal theta-power in the imagine condition and negative
schizotypy. The epoch employed means it is likely these measures of theta-
power reflect processes contributing to the content-specific retrieval of imagined
items, and post-retrieval processes acting in service of differentiating imagined
items in EM. Results are discussed in terms of suggestions for interventions and
directions for future research.
Doctoral Theses
Doctoral College
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