1. T HE EFFECT OF SYMBOLIC AND NON - SYMBOLIC FORMATS ON ARITHMETIC IN CHILDREN : A DEVELOPMENTAL F MRI STUDY Lien Peters, Hans Op de Beeck & Bert De Smedt 14/03/2015 – ICPS Conference, Amsterdam

2. B ACK TO BASICS Numerical magnitudes in different formats  Non-Symbolic  Symbolic

3. B ACK TO BASICS Neural model of number processing & arithmetic: Triple Code Model Dehaene & Cohen, 1995, 1997

4. B ACK TO BASICS Arithmetic  Direct route Solution is retrieved from semantic memory (= arithmetic facts  verbal code)  Indirect route Procedural manipulation need to be performed (  magnitude code) ?

5. B ACK TO BASICS Number processing  Number comparison task Kaufmann et al., 2011

6. B ACK TO BASICS Arithmetic  Whole brain activation  Activation ~ task complexity and math ability  All studies used Arabic digits as stimuli Kaufmann et al., 2011

7. C URRENT S TUDY ? The neural correlates of arithmetic in symbolic and non-symbolic formats in children

8. W HO ? 23 children (9 – 12 years old)  12 males  Mean age = 10.67 years old  One discarded in analyses of imaging data, due to excessive movement in the scanner

9. H OW ? Session 1  Behavioral measures  Dummy scanner: practice round Session 2  Real scanner

10. H OW ? – S ESSION 1 Arithmetic ability  Tempo Test Calculation Reading ability  One-Minute Test  Klepel Intelligence  WISC-III subscales block design & vocabulary

11. H OW ? – S ESSION 2 Subtraction task  Number domain up to 10  Dot patterns, Arabic digits, number words  = or ≠ reference magnitude (4 or 5)

12. H OW ? – S ESSION 2 Subtraction task  Block design  255 seconds per run, 4 runs per participant

13. B EHAVIORAL RESULTS MSDMinMax Tempo Test Calculation 108.5521.2664138 One-Minute Test 62.8613.414394 Klepel 61.8614.284198 Block Design 13.092.65918 Vocabulary 11.452.94319 General measures

14. B EHAVIORAL RESULTS Behavioral results: subtraction task RT (in s) Accurac y

15. I MAGING RESULTS Digits – Words No significant activation Words – Digits Primary visual cortex

16. I MAGING RESULTS Dots – Digits/Words Parietal lobule, frontal and occipital areas Digits/Words – Dots Angular gyrus & Superior temporal gyrus

17. I MAGING RESULTS Dots – Digits/Words Parietal lobule, frontal and occipital areas Digits/Words – Dots Angular gyrus & Superior temporal gyrus Retrieval?Manipulation?

18. C ONCLUSIONS Digits ≈ Words  Words > Digits in primary visual cortex probably due to more visual information

19. C ONCLUSIONS Symbolic (Digits & Words)  Superior temporal gyrus & angular gyrus ~ verbal arithmetic fact retrieval? Non-symbolic (Dots)  Superior parietal lobule (≈ intraparietal sulcus) ~ manipulation of quantities?

20. C ONCLUSIONS Difference in neural activation between symbolic and non-symbolic formats might reflect a difference in strategy use (fact retrieval vs. manipulation of quantities)

21. C OMING UP NEXT SEASON Expand subject sample  Children with dyslexia & dyscalculia  Compare neural activation during calculation in different formats with typically developing children

22. T HANKS TO … Research unit Biological Psychology, KU Leuven Research unit Parenting & Special Education, KU Leuven Prof. Bert De Smedt Prof. Hans Op de Beeck All children & parents

23. T HANK YOU FOR YOUR ATTENTION ! Questions?