CHRONOMETRICS Processing time and movement control.

CHRONOMETRICSProcessing time and movement control

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?

Reflexes

The book balance task…

Ho-hum…Blindfold

Reflexes


Hey!!Blindfold

Reflexes


Hey!!Blindfold

What happens next?

Reflexes


Hey!!Blindfold

Reflexes


Whoa..Blindfold

Reflexes


Phew…Blindfold

Reflexes


Book added

EMG

Hand

Movement

M1 M2 M3

0 40 80 150Milliseconds

Reflexes

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

response

Wadman et al. 1979

Let’s ‘put the (time) pressure on’ these reflexes, and see what they do…

T1

T2

T3 T4

Normal EMG

EMG for blocked movement

Wadman et al. 1979

Biceps

0 (T1) T2 100(T3) T4 200 300

Triceps

EMG

UNDER THE SKINProcessing time for sensory information

Time Zero

Nothing is happening yet - everything is

connected, but there is no information flow about this movement

Time 2 - 50ms

Information about the first 10ms of

movement is available via M1 pathway.

M2, M3, TR pathways not yet

completed

Time 3 - 100ms

Information about the first 60ms of movement is

available via M1 pathway.


movement is available via M2

pathway.

Time 4 - 175ms


movement is available via M1 pathway.


movement is available via M2

pathway.

Information about the very beginning of movement is just becoming available via

M3 pathway.

So what?

Time delay between current state and feedback regarding current state

Need for forward models An old example…

So what?

And a newer one…

So what?

And another…

Is the “forward” model learned?

CHRONOMETRICS Processing time and movement control.

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