Motor System

Question 1

Evidence suggests that the primary motor cortex is organized on the basis of_____.

Answer 1

Elemenatry lexicon of movements

Question 2

Disruption of movement sequences, in the absence of muscle weakness, would follow lesions of the_____.

Answer 2

Basal Ganglia

Question 3

Neurons that respond both when the subject performs an action and when the subject observes the action being performed are called_____ neurons.

Answer 3

Mirror Neurons

Question 4

The planning of motor movements seems to be the primary responsibility of neural circuits in the______.

Answer 4

Prefrontal Cortex

Question 5

motor system

Answer 5

usually reserved for those parts of
the nervous system that take part most directly in producing movement
and for the spinal cord neural circuits that issue commands to muscles
through the peripheral nerves

Question 6

posterior cortex

Answer 6

specifies movement goals and sends sensor information from vision, touch, and hearing
into the frontal regions via multiple routes

Question 7

prefrontal cortex

Answer 7

generates plans for movements that it passes along to the premotor and motor cortex

Question 8

premotor cortex

Answer 8

houses a movement repertoire, its own lexicon, that among other things recognizes
other’s movements and selects similar or different actions

Question 9

Difference between the M1 and premotor

Answer 9

The lexicon of the primary motor cortex M1, or also Brodmann’s area 4
consists of more elementary movements than premotor lexicon, including
hand and mouth movements.

Question 10

When a movement goal arises in the posterior cortex…….

Answer 10

there are two toutes for action. If a movement is relatively simple, then the
premotor and motor cortex execute the action. If planning is required,
the temporal and prefrontal cortices make decisions and then the
premotor and motor cortices execute the appropriate movements

Question 11

Motor Homunculus

Answer 11

In his work, Penfield summarized the results of his motor studies
using cartoons of body parts to represent the area of M1 and the
premotor cortex where stimulation caused those parts to move.

The motor Homunculus is upside down relative to the actual
body, with the feet located dorsally within the central fissure and
head located ventrally just above the lateral fissure.

Penfield located a secondary Homunculus in the supplementary motor
cortex.

There may be as many as 10 Homunculi within the motor and premotor cortices.

Question 12

Michael Graziano and Ethological Categories of Movement

Answer 12

In 2009, Michael Graziano used trains of electrical stimulation of 0.5
seconds in conscious monkeys. He found that stimulating elicits action
that he calls Ethological Categories of Movement, meaning that each
region represents three types of organizations: the body part to be
moved, the spatial location to which the movement is directed, and the
movement’s function.

Question 13

Why are Ethological Catergories of Movement important?

Answer 13

This motor representation shows that many
cortical maps of the body exist, but each map represents a different
action. The part of space in which an action is to take place and that
action’s intended function.

Question 14

TF: The motor cortex is not the only region from which movements can be
evoked

Answer 14

True. Similar functional movements can be elicited by electrically
stimulating the parietal cortex because parietal topography mirrors the motor homunculus and to
guide reaching to a target, the visual cortex has to identify both the location of an object and the object itself. Based on information about the object location, the visual cortex instructs the parietal arm region about the object’s location, and the hand region about how to shape the digits to grasp the object

Question 15

TF:A large part of learning to move entails learning how to use pre-organized
movement patterns to achieve both skill and strength.

Answer 15

True: Part of the role of the neocortex in movement must thus be to blend together motor
reflexes to form learned skilled actions.

Question 16

When, in perfoeming an action do motor neurons fire?

Answer 16

Before the action (planning)
During the action(executig)

Question 17

TF: Neurons will fire at an equal rate when lifting a 5 pound bell veruss lifting a 25 pound bell

Answer 17

False, The more force needed, the higher the firing rate

Question 18

TF:It is possible that the motor cortex calculates both the direction and the distance of
movements

Answer 18

True, For example, As a monkey’s arm moves in directions other than the one to which a particular cell maximally responds, this cell decreases its activity in proportion to
the displacement from the preferred direction.

Question 19

Mirror Neurons and Why theyre important

Answer 19

cells in the primary and premotor cortex fire when an individual observes a specific action taken by another individual

The flexible properties of mirror neurons underlie our inner ability to imagine movements. The
ability to understand the actions of others. Therefore, we understand our own actions and those of others by internally replicating the movements.

Question 20

Core Mirror Neuron v Distributive Mirror Neuron

Answer 20

The core mirror neuron system is transitive, responding to a wide range of
actions that might be used to obtain a goal.

The distributed mirror
neuron system responds to intransitive actions, movement in which a
goal is not present.

Question 21

How many pathways originate in the brainstem and connect to the spinal cord? Why are they important

Answer 21

26; These important pathways, send information
pertaining to posture and balance from the brainstem to the spinal
cord, and control the autonomic nervous system

Question 22

Movements governed by the brainstem tend to be…

Answer 22

whole body movements

Question 23

Why is Walter Hess important?

Answer 23

In 1957, Walter Hess developed the technique of implanting and cementing
electrodes into the brain of cats and other animals. When he
stimulated the brainstem of a freely moving animal, he was able to
elicit almost every innate movement that an animal of that species
might make. The animal’s emotional behavior also could be modulated.

Question 24

Besides motor control, what else does the brainstem do?

Answer 24

Other brainstem functions pertain to controlling movements used in
eating and drinking, and in sexual behavior. The brainstem is also
important for posture, for the ability to stand upright, and make
coordinated movements of the limbs for swimming and walking, and for
moments used in grooming and making nests.

Question 25

Basal Ganglia

Answer 25

a collection of sub-cortical nuclei in the forebrain, connect the motor cortex with
the midbrain, and connect the sensory regions of the neocortex with
the motor cortex.

Lesion studies show how elevant are the basal ganglia in the control of moment. Dyskinesias,
or unwanted movements, for example, twitching, that can result as a function of lesion to the caudate and putamen. The genetic disorder named Huntington’s disease destroys caudate and putamen cells, and is characterized by involuntary and exaggerated movements.

Question 26

Where does the basal ganglia recieve from ? Where does it project to?

Answer 26

The basal ganglia receives inputs from two main sources. One, all
areas of the neocortex and limbic cortex, including the motor cortex.

Two, the nigrostriatal dopamine pathway, extending into the basal
ganglia from the substantia nigra, a cluster of darkly pigmented cells
in the midbrain.

The basal ganglia sent projections back to both the
motor cortex and the substantia nigra.

Question 27

Parkinson’s disease

Question 28

Basal Ganglia Damage can cause which two opposing deficits

Answer 28

hyperkinetic and hypokinetic, that occur if the basal ganglia are damaged, suggest thatb one of its jobs is to modulate movement

Question 29

Basal Gangliaand its Pathways

Answer 29

One is inhibitory, and the other one is excitatory. The
two pathways converge in an area of the basal ganglia called the
internal part of the globus pallidus, GPI. The GPI, in turn, projects
to the thalamus, specifically to the anterior thalamic nucleus, and
the thalamus projects to the motor cortex. The GPI acts like a volume
control, because its output determines whether a movement will be weak
or strong.

Question 30

The Cerebellum

Answer 30

The cerebellum seems to be the motor system component that participates in
acquiring and maintaining motor skills

The cerebellum seems to be the motor system component that participates in
acquiring and maintaining motor skills

It has been shown that the cerebellum
has a role in movement timing, and helps maintaining movement
accuracy. In addition to its role in motor learning, the cerebellum
participates in copling movements so the flow of action appears
seamless.

Question 31

Describe the structures of the cerebellum

Answer 31

The flocculus receives projections
from the vestibular system, and so takes part in controlling balance.
Many of its projections go to the spinal cord and to the motor nuclei
that control eye movements.

The most medial areas of the cerebellum are associated with the face
and body’s midline.

Those more lateral are associated with movements
of the limbs, hands, feet, and digits

Question 32

Damage to the mid-cerebellum does what?

Answer 32

Tumors or damage in midline
areas of the cerebellum disrupt balance, eye movements, upright
posture, and walking, but do not substantially disrupt other movements
such as reaching, grasping, and using the fingers.

Question 33

Damage to the Lateral cerebellum does what?

Answer 33

amage to lateral parts, instead, disrupt arm, hand, and finger
movements far more than movements of the body’s trunk.