Chapter 11: motor skills and action

Question 1

Muscle movement

Answer 1

Motor neurons in the spinal cord send signals to the muscles. They send the upper muscle the message to contract and the under muscles the message to stretch. These motor neurons orgiginate in the spinal cord and receive information from the muscle spindles inside the muscle that tell them how much the muscle is stretched.

Question 2

Basal ganglia

Answer 2

Consists of the caudate nucleus, putamen, globus pallidus, substantia nigra and the subthalamic nucleaus. The caudate nucleus and the putamen also form the striatum. Information in the basal ganglia is processed via the direct and indirect route:
- Direct route: has an activating effect.
- Indirect route: has an inhibitory effect.

Question 3

Parkinson’s

Answer 3

In Parkinsons there is a degeneration of dopamine-producing neurons in the sunstantia nigra, which results in a deficiency of dopamine in the striatum. This causes the direct pathway to be less active and the indirect pathway to be more active, thus inhibiting more movements (hypokinesia).

Question 4

Hypokinesia

Answer 4

Lack of movement.

Question 5

Huntington’s

Answer 5

Involves loss of neuron in the striatum, which results in an underactive indirect pathway, which causes more movements to occur (hyperkinesia).

Question 6

Hyperkinesia

Answer 6

An excess of involuntary movements.

Question 7

Cerebellum

Answer 7

Mainly involved in fine-tuning movements and predicting movements. Not the generation of movements.
Consists of several parts:
- Vestibulocerebellum: receives input about head position and changes the head position and eye focus in movement.
- Spinocerebellum: receives sensory and motor information about the libs. Can help with balance in the trunk and limbs via projections to the thalamus and motor cortex.
- Neocerebellum: has projections to and from the cortex, thalamus, frontal brain areas and the motor cortex (for planning and executive momvements).

Question 8

Cerebellar ataxia

Answer 8

Uncoordinated movements

Question 9

Dysmetria

Answer 9

When making eye and hand movements, people overshoot their target or stop too early.

Question 10

3 aspects for smooth muscle control

Answer 10

1. Movements in the central nervous system must be represented in motor programs.
2. Sensory information must be used during movement.
3. Agency: the feeling that you are the one who causes the movement.

Question 11

Mirror neurons

Answer 11

Active when performing a movement and seeing someone else perform this movement. The posterior parietal cortex is seen as part of the mirror neuron system. Mirror neurons are part of the system that creates empathy.

Question 12

Forward model

Answer 12

Predictions of the consequences of an action can be bade of the basis of an internal model of the motor system. This can explain why we don’t feel ticklish when we touch ourselves, but we do when someone else touches us.

Question 13

Body schema

Answer 13

A representation of the body that is used in controlling movements. This is not consciously accessible.

Question 14

Body image

Answer 14

A body representation that is stable of time and consciously avialable.

Question 15

Peripersonal space

Answer 15

The space around the body, used in trying to avoid something that is thrown at you or just not standing too close to another person.

Question 16

Apraxia

Answer 16

The inability to perform specific predifined acitons or to carry out learned and purposeful movements. Caused by damage to the left parietal lobe, right parietal regions, temproal and frontal cortex.

Question 17

Ideomotor apraxia

Answer 17

People form a concept of the action to be performed, allowing them to recognize the function of certain tools, but not to use them correctly.

Question 18

Ideational apraxia

Answer 18

People show impairments in making meaningful motor sequences and using tools, while the imitation of movement is relatively intact.

Question 19

Damage implications

Answer 19

• Frontal areas: disruption of movement production.
• Dorsal brain regions/superior parietal lobe: impairments in the imitation of meaningful gestures.
• Inferior parital cortex: disruption in mimicking of object use.
• Temporal lobe/ventral pathway: severe apraxia.

Question 20

Alien hand syndrome

Answer 20

Involuntary, seemingly autonomic movements of the affected hand that go against the patients verbally reported intention.