APA 3120 motor synchronicity

What is the first step in the neural pathway for voluntary muscle contraction?

Motor planning - determining what movement should occur.

What is the role of the primary motor cortex in muscle contraction?

It initiates the movement.

What follows the initiation of movement in the neural pathway?

Signal transmission through descending pathways.

Where does synapse occur in the neural pathway for muscle contraction?

In the spinal cord.

What is the final step in the neural pathway for muscle contraction?

Stimulation of the effector (muscle).

What does mental chronometry measure?

The interval between stimulus presentation and response initiation.

What are the three stages of mental chronometry?

Stimulus identification, response selection, and movement programming.

What is motor programming?

The process of organizing and preparing motor commands before movement execution.

Why is motor programming important?

It ensures movements are coordinated in time, space, and force.

What does motor time represent?

Muscular processes required to overcome inertia.

What does premotor time represent?

The central processing time before movement initiation.

What is the function of electromyography (EMG)?

To measure the electrical activity of muscles.

What are the modes of control in motor responses?

Reactive, predictive (anticipatory), and self-paced (projective).

What is the problem when making different limbs move simultaneously?

Limbs differ in mass, neural conduction time, and pathway lengths.

How does the brain compensate for different limb movements?

By activating the foot earlier to account for conduction delay.

What is an internal model in the context of movement?

The brain's prediction of the sensory consequences of movement.

What is an efference copy?

A copy of the motor command sent to the prediction system.

What happens if predicted sensory feedback matches actual sensory feedback?

The movement is considered correct.

What is the significance of anticipatory timing adjustments?

They allow for coordinated movements despite conduction delays.

What is the interval of time between stimulus presentation and response initiation called?

Reaction time.

What is movement time (MT)?

The interval of time between the initiation and completion of movement.

What does the foreperiod refer to in motor response?

The time between the warning signal and the 'go' signal.

What is the reactive condition in the experiment?

Participants react to a visual 'go' signal by lifting their heel and finger simultaneously.

What is the self-paced condition in the experiment?

Participants lift their heel and finger at their own pace, counting to 4 before completing the action.

How do pre-motor times compare in the reactive condition?

Pre-motor times are similar, but the hand may move slightly earlier than the foot.

What factors influence movement onset times in the reactive condition?

Length of motor pathways and mass of the limb to be moved.

What happens to central motor commands in the reactive condition?

They are co-activated simultaneously in response to the go signal.

In the self-paced condition, which movement activates earlier?

The foot activates earlier than the hand.

What is the significance of sensory feedback in the self-paced condition?

Sensory feedback signals indicate that movements were performed simultaneously.

What does the internal model in motor control involve?

It includes motor commands, spinal cord activity, and the comparator for predicted sensory consequences.

What is the role of the efference copy in motor control?

It predicts sensory consequences of movements to help in coordinating actions.

What characterizes responses in deafferented patients?

Responses are initiated at the same time for both tasks, with hand activation occurring earlier.

How do activation patterns in deafferented patients differ from normal subjects?

Deafferented patients adopt a reactive mode of control, while normal subjects change control modes based on the task.

What is the hypothesis confirmed by the behavior of deafferented patients?

Self-paced synchronous movements are planned according to anticipated sensory consequences.

What is the primary focus of the reactive task?

To prioritize simultaneous pre-motor activity.

What is the primary focus of the self-paced task?

To prioritize simultaneous responses.

What is the significance of command delays in the self-paced condition?

They account for nerve conduction time and limb mass.

What do both conditions (reactive and self-paced) suggest about motor control?

They highlight the differences in how central commands are activated and executed based on task type.

What is the relationship between pre-motor time and response time?

Pre-motor time occurs before response time and is influenced by the task conditions.

What does the term 'central executive' refer to in motor control?

It refers to the brain's processing center that receives afferent sensory information from the finger and heel.

What are the implications of the findings for understanding motor control?

They provide insights into how different tasks influence the timing and coordination of motor commands.

What is the expected outcome of the reactive condition regarding movement timing?

Both movements (heel and finger) are expected to occur simultaneously in response to the go signal.