Abstract
Prolonged response times are observed with targets having been presented as distractors immediately before, called negative priming effect. Among others, inhibitory and retrieval processes have been suggested underlying this behavioral effect. As those processes would involve different neural activation patterns, a functional magnetic resonance imaging (fMRI) study including 28 subjects was conducted. Two tasks were used to investigate stimulus repetition effects. One task focused on target location, the other on target identity. Both tasks are known to elicit the expected response time effects. However, there is less agreement about the relationship of those tasks with the explanatory accounts under consideration. Based on within-subject comparisons we found clear differences between the experimental repetition conditions and the neutral control condition on neural level for both tasks. Hemodynamic fronto-striatal activation patterns occurred for the location-based task favoring the selective inhibition account. Hippocampal activation found for the identity-based task suggests an assignment to the retrieval account; however, this task lacked a behavioral effect.
Highlights
Selective attention helps us to achieve efficient goal directed behavior
The selected and attended information, unattended information is processed and influences processing of subsequent stimuli [2]. This was observed in experiments comparing response times for experimental conditions in which an ignored distractor was subsequently repeated as target with conditions of no repetition
Called negative priming (NP) response time effects give evidence for the existence of different processes underlying DT and control trials (C = trials without repetition)
Summary
Selective attention helps us to achieve efficient goal directed behavior. It describes the ability to focus on goal relevant attributes of our internal or external environment. In so called ignored repetition trials, the distractor of the current display (prime) becomes the target stimulus in the following display (probe) [5] This results in prolonged response times compared to conditions without identity repetition (behavioral NP effect) [6]. According to the feature mismatch account, location-based NP effects result from the occupation of one and the same visual location by different stimuli on prime and probe This causes feature mismatch in DT situations, wherefore they are processed less efficient compared to control trials. Discussed accounts are the inhibition and the episodic retrieval account It remained unclear until now whether or not location-based and identity-based paradigms are mediated by different processes. Activation in similar brain regions are expected for DT and DTTD compared to C trials for each of the two paradigms (location-based and identity-based) used in this study. The study was done in healthy subjects in order to establish the paradigm for further research
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