Lecture 23: Kinesthesia

Question 1

Kinesthesia is the awareness of :

Answer 1

the position of the body segments in space and in relation to each other

Question 2

Kinesthesia allows us to :

Answer 2

perform movements without continuous visual control, to adjust patterns of control variables, and perform tasks requiring multi-limb coordination.

Question 3

_______ are the source of kinesthetic information.

Answer 3

Proprioceptors

Question 4

Problems with Kinesthesia: Under isometric conditions, an increase in the level of muscle activation leads to _____.

Answer 4

an increase in the activity of the gamma system and an increase in the firing level of muscle spindle sensory endings.

This may be interpreted by the central nervous system as a joint motion corresponding to an increase in muscle length.

Question 5

Problems with Kinesthesia: Under non-isometric conditions, an increase in the level of muscle activation leads to _____

Answer 5

muscle shortening, accompanied by an increase in the activity of the gamma system.

As a result, one may see the same average level of firing of muscle spindle sensory endings at different joint positions.

Question 6

Kinesthetic Perception Problems: Under isometric conditions, an increase in the level of muscle activation leads to _____.

Answer 6

an increase in the stiffness of muscle fibers.

This leads to a relative shortening of muscle fibers and a stretching of the tendon.

Question 7

Kinesthetic Perception Problems: Joint torque is the sum of ____.

Answer 7

products of muscle forces and corresponding lever arms

Question 8

Kinesthetic Perception Problems: Joint movement leads to a change in the lever arm. Therefore, joint torque is dependent on ____.

Answer 8

both muscle force and joint angle.

Question 9

If a system within the human body looks imperfectly designed, we have probably ________.

Answer 9

overlooked or misinterpreted something.

Question 10

Accurate kinesthetic perception is likely to emerge through participation of ______________.

Answer 10

signals from various sensors

Question 11

Kinesthesia has more ______ than _____.

Answer 11

positive features than problems

Question 12

_________ sense is still present with artificial joints.

Answer 12

Position

Question 13

An efferent copy represents _____.

Answer 13

a copy of a voluntary motor command

Question 14

Efferent copy participates in ______.

Answer 14

deciphering the mixed information from peripheral receptors, thus reducing the cognitive load.

Question 15

Spindle activity is dependent on ______.

Answer 15

gamma activity, which is dependent on the current descending motor command.

Question 16

According to the equilibrium point hypothesis, motor command to a muscle can be described as a ______.

Answer 16

fixed force-length characteristic (the tonic stretch reflex characteristic)

Question 17

Motor command to muscle allows only certain combinations of muscle force and length to occur in a static state and solves _____.

Answer 17

half the problem of muscle force and length perception.

Question 18

A motor command may be associated with_______.

Answer 18

two characteristics on the force-angle plane.

Question 19

The first characteristic that the motor command may be associated with corresponds to a ________.

Answer 19

chosen value of the central command (the efferent curve)

Question 20

The second characteristic that the motor command may be associated with corresponds to a ______.

Answer 20

certain level of activity of proprioceptors (the afferent curve)

Question 21

The intersection of the characteristics associated the motor command defines _________.

Answer 21

current values of muscle length and force.

Question 22

Kinesthetic perception is based on ____.

Answer 22

signals from proprioceptors.

Question 23

Each proprioceptor provides information that by itself is ______ to extract values of joint angles or torques.

Answer 23

insufficient

Question 24

the combined information is ______.

Answer 24

sufficient

Question 25

A copy of motor command signals (efferent copy) likely plays a key role in ______.

Answer 25

kinesthetic perception.