1. An ERP investigation of response inhibition in adults with DCD Elisabeth Hill Duncan Brown José van Velzen

2. Background Response inhibition - crucial for goal-directed behaviour in changing environment  Frontoparietal network implicated (behavioural / ERP) Mixed findings in children with DCD (e.g. Wilson et al., 1997; Mandich et al. 2002, 2003; Querne et al. 2009) Adults?

3. Aims Enhance understanding of response inhibition in DCD (Go/NoGo task) Identify neurological mechanisms involved (with benefits for theory and intervention?) Provide behavioural and neurophysiological evidence for continuation of coordination difficulty in adults with DCD

4. Movement battery: p<.001 Participants

5. MIDLINE CROSSING STRAIGHT Infra-red starting position Possible probe LED Target button Experimental set-up Go/NoGo (delayed response) paradigm

6. 1000 msec between trials Experimental set-up

7. 1000 msec between trials 900msec Hand cue: 200 msec

8. 1000 msec between trials 900msec Hand cue: 200 msec

9. 1000 msec between trials 900msec Probe flashed: 100 msec Hand cue: 200 msec

10. GO 1000 msec between trials 900msec 200msec Probe flashed: 100 msec STOP Hand cue: 200 msec **

11. GO 1000 msec between trials 900msec 200msec Response initiated or withheld Probe flashed: 100 msec STOP Hand cue: 200 msec ** N200 150-350 msec post STOP P300 250-450 msec post STOP

12. Dependent variables Compare:  Group (DCD vs. typical)  Movement type (straight vs. midline) Behavioural results:  Inhibitory errors (fail to STOP) ERPs:  N200; P300

13. ERP predictions N200 / P300:  increased in midline vs. straight movement (typicals)  decreased and delayed in DCD (vs. typical)

14. Behavioural results group p<.001; movement p.001 group x condition p<.05

15. N200 (150-350 msec post STOP) Frontal regions group.005; movement ns group x movement ns

16. P300 (250-450 msec post STOP, shown 300-600 msec ) Central regions group ns; movement ns group x movement ns

17. Summary More inhibitory errors in DCD vs. typical group N200:  Greater enhancement in typical vs. DCD group P300:  No differences between groups

18. Implications Inhibition (Go/No go) difficulties in adults with DCD Biological underpinning (electrophysiological correlates) Possible involvement of anterior cingulate cortex (ACC), prefrontal cortex (PFC) cf. N200? Lifespan development

20. –EEG was recorded continuously with Ag/AgCl electrodes via 64 channel Biosemi system with linked earlobe reference. –Signals were amplified with a bandpass width of 0.1- 100Hz and sampling rate was set at 512 Hz. –Data segments were epoched to 100 ms prior to onset of probe onset and 500 ms after probe onset for each movement condition. –Individual trials containing eye movement artifacts and errors were rejected before the averaging process. –Early visual-spatial potential N1(amplitude) was isolated (defined as negative going peak 100-300 ms post probe onset) and used for comparison of sensory gating of attended locations within visual perception EEG acquisition