Quiz: Motor System

T/F: The firing of primary motor cortical neurons occurs precisely at the onset of a muscle contraction.

1. False

1. T/F: primary motor cortical neurons can be directionally selective.

1. True

1. T/F: the firing rate of a primary motor cortical neuron codes for or contributes to the force of a movement

1. True

1. T/F: The directional control of a movement is coded by the activity of a population of primary motor cortical neurons.

1. True

1. T/F: the directional responses of primary motor cortical pyramidal cells tend to be broadly tuned in that they respond over a somewhat broad range of movement directions

1. True

1. As the motor unit increases, which property of the alpha motor neuron decreases?

1. Excitability

1. As motor unit size increases, which property of the alpha motor neuron increases?

1. Cell body size

2. Axon diameter

3. Number of axonal branches

1. While helping a friend move, you hold out your arms to take a box from your friend. To ensure that you do not drop the box,  your _____ neurons send a signal to your ___ neurons to contract your biceps and relax your triceps

1. Group Ia afferent; alpha motor

1. Which proprioceptive sensory circuit prevents muscles from generating excessive tension and maintains steady muscle tone during muscle fatigue? 

1. Golgi tendon organs

The lateral corticospinal tract innervates α motor neurons that are important for which task?

1. Writing

The pyramidal cells of the primary motor cortex are located in which cortical layer?

5

1. Pacemaker neurons rhythmically and continuously fire bursts of action potentials because of.... 

1. Sodium leak channels

1. The brain areas highlighted orange and red, respectively, are the… 

1. Premotor cortex and primary motor cortex

The local circuits in the spinal cord that are fully capable of controlling the timing and coordination of complex locomotion are called... 

1. Central pattern generators

1. The area of the brain dedicated to speech production is ... 

1. Broca’s

1. Where are lower motor neurons located in the spinal cord?

1. D

1. _______ innervate striated muscle fibers, and _______ innervate specialized sensory muscle fibers called _______. 

1. α motor neurons; γ motor neurons; muscle spindles 

1. A person with damage to the direct motor pathway but an intact indirect motor pathway, would have the most difficulty .... 

1. tying their shoes