Postersession 2
Poster #: 11
Topic: Attention and distraction
Thursday, Sep 10, 2015
1st floor

Visual mismatch negativity, working memory load and processing mode

Kertu Saar1, Nele Põldver2, Mai Toom3, Annika Kask3, Madli Uutma3, Jüri Allik4, Risto Näätänen5, & Kairi Kreegipuu3

1Institute of Psychology, University of Tartu, Tartu, Estonia
2Department of Psychology, University of Tartu, Tartu, Estonia
3University of Tartu, Tartu, Estonia
4University of Tartu; Estonian Academy of Sciences, Estonia
5University of Tartu; University of Helsinki; University of Aarhus, Estonia

MMN is widely considered an attention-independent component of deviance detection. We are interested in how visual MMN to task-unrelated, unattended stimuli acts as a function of working memory occupancy and processing mode (visual or verbal). Our subjects performed several n-back tasks with different levels of working memory engagement (0-back – simply responding to a target, i.e. smaller cognitive load; or 2-back – continuously comparing the current stimulus to the one presented 2 steps back, i.e. bigger cognitive load) and varying stimulus types (schematic emotional faces or capital letters). Some letters were also simultaneously presented in the surrounding periphery with an oddball paradigm to elicit MMN. The deviant „T“ was chosen to differ from standard „B“ more visually and less verbally, the deviant „S“ to differ less visually and more verbally. Both letters evoked significant vMMNs during all tasks with insignificant differences between different working memory loads. The MMN was, however, slightly smaller while the subject was performing a more visual central n-back task with face-stimuli, as compared to the somewhat more verbal version with letter-stimuli. That indicates a potential dependence of vMMN on the availability of visual processing resources. As expected, „T“ (the visually more different deviant) also elicited a larger vMMN than „S“, independent of the central task type. Thus, our results indicate that the elicitation of vMMN depends more on processing mode, rather than plain task load. More questions regarding the behavioral results and individual n-back strategies (visual, verbal) will be further addressed on the poster.