Week 2

Question 1

Status?

What is the Forward Dynamic Model?

Answer 1

What is the body’s current status

Position, Velocity, Joint angles

Question 2

Sensory info, Status

What is the sensory model?

Answer 2

While in that status, what sensory infk should the body sense

Tactile sensation, Gravity

Question 3

Sequence, 10 Speeds, Final arm config

What does the look up table do?

Answer 3

Stores a sequence of ten muscles forces when reaching ten different speeds, Finds the desired final arm configuration

If there were 7 joint angles and 10 points per joint, there would be 10 to the 7 configurations

Question 4

Acts as a spring to…

What does a stretch reflex do?

Answer 4

Keeps muscle at desired length

Question 5

M and MS

Where are the alpha and gamma motor neurons in relation to the stretch reflex?

Answer 5

Muscles and Muscle Spindles

Question 6

MC

What do alpha motor neurons cause in relation to the stretch reflex?

Answer 6

Muscle Contractions

Question 7

Adjust S

What do gamma motor neurons do in relation to the stretch reflex?

Answer 7

Adjust sensitivity to cause reflexes

Question 8

G MN

Which motor neurons cause movement from posture?

Answer 8

Gamma motor neurons

Generated by altering the set point of the posture control servo

Question 9

Min

What are muscle spindle discharges recorded using?

Answer 9

Microneuropgraphy

Question 10

Set Point = …, Assumes brain controls a v… e… p…

What is the Equilibrium Point Hypothesis?

Answer 10

Assumes that the brain controls a virtual equilibrium point (which controls the reaching movement)

Question 11

VT

In relation to the Equilibrium point hypothesis, what does the equilibrium point tend to move along?

Answer 11

Virtual trajectory

Question 12

Brain only cares…

What is the main assumption about the EPH?

Answer 12

Brain only cares about the final destination, not how you got there

Equifinality

Question 13

Rotating

What does Coriolis force apply to?

Answer 13

Movement on rotating objects

Question 14

La and Di (1994)

Which hypothesis is the opposite of the EPH?

Answer 14

Lackner and DiZio 1994, Reaching under velocity dependent force

Question 15

Brain also plans E… T…

What is the direct cortical control model?

Answer 15

Brain doesnt only specify equilibrium point, also plans entire trajectory

Question 16

Sm, To and En, Un

What are the properties that the brain tries to optimise?

Answer 16

Smoothness, Torques and Energy, Uncertainty

Question 17

Jerk

How does the brain optimise smoothness in relation to kinematics?

Answer 17

Minimises the jerk of the trajectory

Question 18

Change of…, Predicts KE

How does the brain optimise torques and energy in relation to kinetics?

Answer 18

Minimises the change of torque in the joint, Can predict kinetic effects (Inertia, Force)

Question 19

How does the brain optimise uncertainty?

Answer 19

Tries to minimise it

Probablistic

Question 20

Op o Un

What model is considered the most predominant model for reaching?

Answer 20

Optimisation of uncertainty

Question 21

Noise, Magnitude

What is signal dependent noise?

Answer 21

When the noise of the movement is dependent on the magnitude of the movement

Larger movements are loud, Small slower movements are quieter

Question 22

What do abrupt movements cause in relation to signal dependent noise?

Answer 22

Uncertainty

Question 23

Brain keeps… Fb P for MS

What is optimal feedback control?

Answer 23

Assumes that the brain keeps feedback policies for motor skills

Question 24

Selection, In, Out

What is the optimal control model of movement?

Answer 24

Selects the best input that minimises the output cost

Question 25

TT or EC

What is output cost?

Answer 25

Time taken or energy consumption

Question 26

Shape… Curve… Bead… Gravity… Start and End…Time

What is the brachistochrone problem in relation to the optimal control model of movement?

Answer 26

Find the shape of the curve along a bead which slides under gravity between fixed start and finish points in the shortest time