Movement Neuroscience 2

A corticospinal neuron in primary motor cortex can do all of the following EXCEPT

• Project to multiple motor neuron pools in the spinal cord.

• Participate in the initiation of movement.

• Code for the amount of force of individual muscles.

• Code for the direction of movement.

• Code for the extent of movement.

Which statement accurately describes the relationship between muscle fiber length and force production?

• Muscle fibers generate less force when they are elongated due to reduced passive tension.

• Muscle fibers produce greater force when they are stretched due to increased passive tension.

• Muscle fiber length has no impact on force production.

• Shortened muscle fibers generate more force due to increased active tension.

What is the primary function of muscle spindles?

• Sensing tension and tendon pull in muscles

• Signaling the length and rate of change of length (velocity) of the muscle

• Providing information about the load or force applied to a muscle

• Contracting to generate force during muscle movements

How do Golgi tendon organs contribute to muscle function?

• Sensing the length and rate of change of length of the muscle

• Providing information about the load or force applied to a muscle

• Contracting to generate force during muscle movements

• Assisting in muscle relaxation by inhibiting muscle contraction

Which statement is false regarding the relationship between force and velocity in muscles?

• Muscle velocity generally decreases as force increases.

• Muscle velocity increases non-linearly as the force decreases from a high value.

• The force reduces faster in short fibers than long fibers as the muscle velocity increases.

• None of the statements are false.

Which of the following statements accurately describes the function of a Renshaw cell?

• Renshaw cells are excitatory interneurons that enhance the firing rate of motor neurons.

• Renshaw cells innervate and inhibit the motor neurons that activated them, forming a negative feedback loop.

• Renshaw cells are specialized sensory receptors responsible for detecting muscle tension.

• Renshaw cells regulate the production of neurotransmitters in the motor neurons.

Which statement accurately describes the influence of the volume conductor on motor unit action potentials (MUAPs)?

• The amplitude of MUAPs is always directly proportional to the size of the motor unit.

• The volume conductor has no effect on the amplitude of MUAPs.

• MUAP amplitude can vary due to factors like the distance between the electrode and the motor unit and the conductivity of surrounding tissues.

• MUAP amplitude is solely determined by the strength of the neural drive.

What does the non-linearity between the strength of neural drive to the muscle and EMG amplitude imply?

• EMG amplitude is directly proportional to the strength of neural drive.

• There is no relationship between neural drive and EMG amplitude.

• The relationship between neural drive and EMG amplitude is not always linear and may depend on various factors.

• EMG amplitude decreases as neural drive increases.

How is neural drive to muscles typically estimated?

• By directly measuring the force exerted by the muscles.

• Through visual observation of muscle contractions.

• From the discharge times of motor units.

• By analyzing the color changes in the muscle tissue.

Which statement about HD-EMG decomposition is false?

• HD-EMG decomposition involves blind source separation (BSS) procedures.

• The optimization of motor unit separation filters is based on a measure of sparseness for the motor unit spike train within a predefined time interval.

• BSS procedures usually estimate one motor unit spike train at a time by iteratively optimizing the motor unit separation filter and applying it to the recorded EMG signals.

• HD-EMG decomposition relies solely on visual inspection to separate sources (motor units).