1. Investigating Occipito-Temporal Contributions to Reading with TMS Keith J. Duncan, Chotiga Pattamadilok & Joseph T. Devlin Cognitive, Perceptual and Brain Sciences University College London, UK

2. Background vOTC lesion causing reading impairment Left ventral occipito-temporal cortex (vOTC) R R

3. Lexical VWFA representation of visual words Pre-lexical VWFA representation of letter bigrams Visual Word Form Area Hypotheses of vOTC

4. General Methods & Depth Task: Visual Lexical Decision fMRI-guided TMS Task: Visual Lexical Decision fMRI-guided TMS vOTC M1 Mean Depth 26 (  0.9)mm27 (  0.9)mm M1

5. * CPWLFHF Experiment 1 (n=14) 400 500 600 RT (msec) CPWLFHFCPWLFHF TMS slowed LF word responses (+34msecs) vOTC General intersensory facilitation Vertex Similar pattern to vOTC LOC WordsNonwordsWordsNonwordsWordsNonwords

6. Experiment 2 (n=26) Slowed RTs for LF words ◦ vOTC stimulation No significant effect ◦ LOC stimulation

7. Experiment 1 & 2 TMS of vOTC interferes with LF word reading Not a general effect of ventral stimulation o No effect of LOC stimulation o No effect on pseudo- or HF-word reading Summary

8. Paired-pulse TMS 0-40, 40-80, 80-120, 120-160, 160-200 msecs post-stimulus Method Experiment 3 (n=24) Investigate time-course of vOTC involvement in reading Paired-pulse TMS 0-40, 40-80, 80-120, 120-160, 160-200 msecs post-stimulus Method

9. Experiment 3: Results ◦ 80-120msecs (+24msec) ◦ 120-160msecs (+25msec) ◦ 160-200msecs (+34msec) ◦ vOTC TMS significantly slowed RTs at: 530 550 570 590 0-4040-8080-120120-160160-200 Vertex RT (msec) Time of ppTMS (msec) vOTC ** * *

10.  TMS of vOTC is possible  Provides novel information  Theories Prelexical VWFA Lexical VWFA TMS of Ventral Occipito-Temporal Cortex Conclusion Other?

11. TMS of Ventral Occipito-Temporal Cortex Maurer et al. Behavioral and Brain Functions 2005 1:13 Chen et al. Cerebral Cortex 2007: 17