Poster D31, Wednesday, August 21, 2019, 5:15 – 7:00 pm, Restaurant Hall
Adaptation of a semantic picture-word interference paradigm to language mapping with transcranial magnetic stimulation
Magdalena Jonen1, Stefan Heim1,2, Marie Grünert1, Georg Neuloh1, Katrin Sakreida1;1RWTH Aachen University, 2Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Germany
Language mapping with neuro-navigated transcranial magnetic stimulation (TMS) helps to identify language-related cortical regions and is mostly applied for clinical purposes. A high spatial resolution approach was proposed to explore cortical sub-areas, such as Broca’s region. Functional imaging data suggested segregated semantic, syntactic and phonological processing in an anterior-to-posterior direction along the inferior frontal gyrus. As yet, in TMS language mapping studies qualitative aspects of language processing have been rated subjectively. We therefore recently introduced a reaction time based picture naming paradigm with phonological picture-word interference (PWI) for more objective TMS mapping, which enables to adress specifically and control the level of phonological processing within Broca´s region. The inhibitory effect of TMS on language processing reduced the behavioral phonological priming effect, which is characterized by accelerated naming responses to target pictures accompanied by auditory presented phonologically related distractor words. Here, we complementarily adapted a semantic PWI paradigm. Semantic relations, particularly categorical relations rather lead to a behavioural semantic interference effect in terms of inhibition of naming responses to target pictures accompanied by visually presented related distractor words. However, semantic priming has been shown for associative semantic relations with a stronger effect for part-whole than functional relations. We therefore chose part-whole relations so that our hypotheses related to TMS-induced inhibition can be transferred. In this study we aimed at the comparison of unimodal presentation, i.e. visual distractors, and multimodal presentation, i.e. auditory distractors, to test for efficiency of naming response acceleration. We used 30 target pictures from a standardized set and combined them with a related distractor and an unrelated distractor from the same set. The item set was controlled for numbers of syllables, phonemes and graphemes as well as low lexical frequency in spoken German language and semantic categories. According to the constraints given by the future TMS study, we created six blocks with 30 target-distractor pairs and a pseudo-randomized session for each participant. Importantly, each target noun was required to be presented with the related and the unrelated distractor at the same position within the block in two out of the six blocks. After familiarisation prior to the experiment, 15 healthy German native speakers were employed in both conditions each. The 2 × 2 ANOVA analysis with the factors RELATION and MODALITY yielded only a marginal significant main effects RELATION. The facilitatory effect, the difference unrelated minus related distractors, was, however, numerically higher in the unimodal condition as compared to the multimodal condition in which no facilitation effect was shown. In a post-hoc item analysis we selected the ten most facilitating target pictures. The restricted analysis of these items supported a stronger semantic facilitation effect in unimodal presentation with visual distractors as compared to multimodal presentation with auditory distractors. Aiming at the most effective design of a semantic PWI in TMS-setting we found a preference for visually presented part-whole distractors. The specific stimulus set showing a stronger semantic faciliation effect may build a basis for efficient TMS language mapping controlling the level of semantic processing directly by the task.
Themes: Meaning: Lexical Semantics, Methods
Method: Behavioral