11. Motor Control of Body Movement

Question 1

Answer 1

Types of Movement

Question 2

Answer 2

For voluntary, most important are the coordination between the cerebral cortex, cerebellum and basal ganglia

Question 3

Voluntary Movement

Answer 3

# Choose to move
able to train to improve movement

Question 4

Reflex

Answer 4

Afferent neuron to joint to muscle, stretches to spinal cord and this sends signal in a negative feedback loop. No message to brain.

Question 5

Answer 5

Voluntary Movement

• Step: Decision making & planning
• Location of action: Cerebral Cortex and Cerebellum
• Step: Initiating the movement
• Location of action: Cerebral Cortex
• Step: Executing the movement
• Location of action: Cerebellum & cerebral cortex (sensory feedback and motor cortex)

Question 6

Motor Areas in the Cerebral Cortex

Primary motor cortex:

Answer 6

SENDS Commands
– Triggers discrete patterns of muscle activation (e.g. finger movements). – Direct connections to motor neurons in the spinal cord.

Question 7

Motor Areas in the Cerebral Cortex

Supplementary motor area:

Answer 7

– Body-wide adjustments to provide the“background” for the more specific movement plans in the premotor and primary motor cortex (e.g. coordination of both hands for bilateral grasping movement, position head and eyes).

– Like premotor area, this region is involved in the planning of movement but does not itself send out direct commands to the motor neurons.

Question 8

Motor Areas in the Cerebral Cortex

Premotor area:

Answer 8

– Plans more complex patterns of movement (e.g. position shoulder and arms so that the hands are properly positioned to perform a task).

– Sends these patterns to the primary motor cortex for execution, either directly or via other brain regions (e.g. basal ganglia).

Question 9

The Cerebellum

Answer 9

• Compares motor signals sent out and sensory information received to monitor and adjusts the execution of movement.
• Major role in the timing of motor activities, and in executing rapid and smooth transitions between successive movements.
• No direct ability to cause muscle contractions; exerts its effects via connections to the other motor areas.

Question 10

Answer 10

Diagram of the cerebellum

3 types

1. maintenance of balance, control of eye movements
2. regulation of muscle tone, coordination of skilled voluntary movement
3. planning and initiation of voluntary activity, storage of procedural memories

Question 11

The Basal Ganglia

Answer 11

• Important in learned, subconscious complex patterns of activity, such as writing, throwing a ball, aspects of speech, etc.
• Part of the neural circuit involved in the cognitive control of motor activity (i.e., linking conscious thoughts to actions).

Question 12

Sensory Input

Answer 12

• Muscles act simultaneously or alternately at different joints to shift the body’s location and position to keep balance
• Continuous input about the body’s position with respect to the surrounding environment, & position of body parts to be received by the brain.
• This information is necessary to establish a neuronal pattern of activity to perform movement
• Peripheral receptors provide this information: proprioceptive input from the skin and muscles themselves combines with visual, auditory and vestibular input to describe body position in space.

Question 13

Control of Voluntary Movements

Answer 13

• The sensory information has been received and the planning and decision making (cerebral cortex and basal ganglia) has been made.
• The cerebellum continually receives and integrates information from the peripheral sensory receptors.
• The motor cortex now takes charge of organising the execution of the throwing motion.

Question 14

Execution of Voluntary Movements

Answer 14

Based on this integrated information, motor output is issued :

• The motor cortex via the corticospinal tracts (in the spinal cord) to the skeletal muscles for execution of the throw.
• The brain stem (reflexes involved in equilibrium and posture).

Question 15

Corticospinal Tracts

Answer 15

A group of interneurons that runs form the motor cortex to the spinal cord.

These tracts cross to the opposite side of the body in the brain stem area known as the pyramids.

They synapse directly with the somatic motor neurons, which innervate the muscles to produce movement.

Question 16

Brain stem

Answer 16

Responsible for several specialized motor tasks (including respiration, cardiovascular, eye movements).

Pathway between higher motor areas and the spinal cord.

Sends out direct connections to motor neurons in the spinal cord, which are important for whole-body movements related to posture and equilibrium > not part of voluntary movement

Question 17

Feedforward Postural Adjustments

Answer 17

As the pitcher begins the pitch, feedforward postural control adjusts body position, shifting weight slightly in anticipation of the changes about to occur.

Each movement activates sensory receptors that feed information back to the spinal cord, brain stem and cerebellum, activating postural reflexes.

These reflexes adjust his body position so that he doesn’t lose his balance and fall as he releases the ball.

Both systems allow for surprising or an impact from the external environment to be compensated for

Question 18

Functions of the ear

Answer 18

Vestibular system - important for balance

• detecting acceleration in different directions

Question 19

Answer 19

Vestibular Apparatus

Question 20

Answer 20

Activation of hair cells in the semicircular canals

Question 21

The utricle

Answer 21

• Together with the Saccule make up the Otolith Organs found in the inner ear
• Located between the Cochlea and the Semicircular Canals

1. position of the head relative to gravity (i.e., static head tilt)
2. Changes in the rate of linear motion (moving in a straight line)