Poster B65, Sunday, March 26, 8:00 – 10:00 am, Pacific Concourse
ERP Measures of Anodal Transcranial Direct Current Stimulation Effects on Second Language Vocabulary Acquisition
He Pu1, Sarah Perlo1, Katherine Gawlas1, Joshua Manning1, Marianna Eddy1,2, Katherine J. Midgley3, Phillip J. Holcomb1,3; 1Tufts University, 2U.S Army Natick Soldier Research, Development, and Engineering Center, 3San Diego State University
Anodal transcranial direct current stimulation (tDCS), which increases cortical excitability of the stimulated neural regions, has been used successfully during artificial word learning (Floel et al., 2008; Meinzer et al., 2014). These previous studies have shown anodal tDCS of Wernicke's area to positively impact word learning, improving translation and recall accuracy performance. In the present study, we tested whether such improvements could be seen during second language (L2) vocabulary acquisition as measured by both behavioral and ERP recordings. As ERP studies on L2 acquisition have shown N400 growth following learning (e.g. Yum et al., 2014), we anticipated larger N400 growth if anodal tDCS successfully facilitates acquisition. Using a double-blind, sham-controlled manipulation, 20 native English speakers (mean age = 21.3, SD = 3.1) learned 100 Spanish words in two sessions across one week. Participants received either active anodal (2 mA) or sham HD-tDCS to Wernicke's area for 20 minutes coinciding with each Spanish vocabulary learning session. Behaviorally, we found no effect of anodal tDCS on post-learning translation accuracy, failing to replicate the previous work on anodal tDCS effects on artificial vocabulary learning. ERP analysis of N400 amplitude growth showed that only the sham and not the active group produced a significant effect of learning (larger N400s to L2 words after learning). This apparent learning inhibition in the anodal group’s ERPs offers some evidence against the trend of anodal tDCS facilitation effects on learning. Possible explanations of these ERP results will be discussed.
Topic Area: LANGUAGE: Other