Cognitive processes and emotion cue processing in introvertive anhedonia

Abstract

Executive cognitive processes and emotion cue processing was explored in introvertive anhedonia, the O-LIFE’s negative schizotypal trait dimension, with the aim of identifying endophenotypes. The experimental work of the thesis was conducted in three distinct parts. The first two used reaction time tasks of selective attention to examine 1) the possibility of a general abnormality in executive cognitive functioning, and 2) the possibility of an emotion cue processing abnormality. Results from these two parts informed the development of the final experiment that used procedures adapted from animal associative learning to examine the interaction between executive cognitive processes and the processing of positive and negative emotional cues in 1) the learning of differentially reinforced biconditional discrimination and 2) the sensitivity to changes in the emotional valence of outcomes. Two experiments, presented in Chapter 2, established that introvertive anhedonia was associated with an executive functioning deficit that could be characterised as a deficiency in processing context. Chapter 3 presented a further three experiments indicating that introvertive anhedonia had blunted processing of negative and positive emotional cues, but under certain specific conditions a bias to the processing of negative stimuli. The final experiment, presented in Chapter 4, found that introvertive anhedonia was behaviourally insensitive to outcome valence changes of stimulus-outcome associations. The blunted processing of valenced stimuli seems to have influenced executive cognitive processes involved in both detecting the changes in outcome valence of associations and in forming new associations. An inability in introvertive anhedonia to adjust behaviour to changes in outcome valence might lead to perseveration, inappropriate responding and, in some situations, an over-exposure to aversive stimuli. The executive cognitive deficits observed in section two, and the emotion cue processing deficits observed in section three might therefore result form failures in common mechanisms.