Lecture 23: Kinesthesia Flashcards
Kinesthesia is the awareness of :
the position of the body segments in space and in relation to each other
Kinesthesia allows us to :
perform movements without continuous visual control, to adjust patterns of control variables, and perform tasks requiring multi-limb coordination.
_______ are the source of kinesthetic information.
Proprioceptors
Problems with Kinesthesia: Under isometric conditions, an increase in the level of muscle activation leads to _____.
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.
Problems with Kinesthesia: Under non-isometric conditions, an increase in the level of muscle activation leads to _____
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.
Kinesthetic Perception Problems: Under isometric conditions, an increase in the level of muscle activation leads to _____.
an increase in the stiffness of muscle fibers.
This leads to a relative shortening of muscle fibers and a stretching of the tendon.
Kinesthetic Perception Problems: Joint torque is the sum of ____.
products of muscle forces and corresponding lever arms
Kinesthetic Perception Problems: Joint movement leads to a change in the lever arm. Therefore, joint torque is dependent on ____.
both muscle force and joint angle.
If a system within the human body looks imperfectly designed, we have probably ________.
overlooked or misinterpreted something.
Accurate kinesthetic perception is likely to emerge through participation of ______________.
signals from various sensors
Kinesthesia has more ______ than _____.
positive features than problems
_________ sense is still present with artificial joints.
Position
An efferent copy represents _____.
a copy of a voluntary motor command
Efferent copy participates in ______.
deciphering the mixed information from peripheral receptors, thus reducing the cognitive load.
Spindle activity is dependent on ______.
gamma activity, which is dependent on the current descending motor command.
According to the equilibrium point hypothesis, motor command to a muscle can be described as a ______.
fixed force-length characteristic (the tonic stretch reflex characteristic)
Motor command to muscle allows only certain combinations of muscle force and length to occur in a static state and solves _____.
half the problem of muscle force and length perception.
A motor command may be associated with_______.
two characteristics on the force-angle plane.
The first characteristic that the motor command may be associated with corresponds to a ________.
chosen value of the central command (the efferent curve)
The second characteristic that the motor command may be associated with corresponds to a ______.
certain level of activity of proprioceptors (the afferent curve)
The intersection of the characteristics associated the motor command defines _________.
current values of muscle length and force.
Kinesthetic perception is based on ____.
signals from proprioceptors.
Each proprioceptor provides information that by itself is ______ to extract values of joint angles or torques.
insufficient
the combined information is ______.
sufficient
A copy of motor command signals (efferent copy) likely plays a key role in ______.
kinesthetic perception.
