1. CHRONOMETRICS Processing time and movement control

2. Introduction  We are opportunistic…  We do as well as we can  Things take time  How much time do things take?  And what impact does this have on movement control  And what impact might this have on brain maturation/development?

3. Reflexes  The book balance task… Ho-hum… Blindfold

4. Reflexes  The book balance task… Hey!! Blindfold

5. Reflexes  The book balance task… Hey!! Blindfold What happens next?

6. Reflexes  The book balance task… Hey!! Blindfold

7. Reflexes  The book balance task… Whoa.. Blindfold

8. Reflexes  The book balance task… Phew… Blindfold

9. Reflexes  The book balance task… Book added EMG Hand Movement M1M2M3 04080150 Milliseconds

10. Reflexes  40ms (ish): M1 reflex  70ms (ish): M2 reflex  100ms (ish): triggered reaction  150ms ( big ish to this one): M3 – conscious response

11. Wadman et al. 1979  Let’s ‘put the (time) pressure on’ these reflexes, and see what they do… T1 T2 T3 T4

12. Normal EMG EMG for blocked movement Wadman et al. 1979 Biceps 0 (T1)T2100(T3)T4200300 Triceps EMG

13. UNDER THE SKIN Processing time for sensory information

14. Time Zero Nothing is happening yet - everything is connected, but there is no information flow about this movement

15. Time 2 - 50ms Information about the first 10ms of movement is available via M1 pathway. M2, M3, TR pathways not yet completed

16. Time 3 - 100ms Information about the first 60ms of movement is available via M1 pathway. Information about the first 30ms of movement is available via M2 pathway.

17. Time 4 - 175ms Information about the first 135ms of movement is available via M1 pathway. Information about the first 105ms of movement is available via M2 pathway. Information about the very beginning of movement is just becoming available via M3 pathway.

18. So what?  Time delay between current state and feedback regarding current state  Need for forward models  An old example…

19. So what?  And a newer one…

20. So what?  And another…

21. Is the “forward” model learned?