1.2 How are motion and perception processed in the brain?

Question 1

Neuroprothesen

Kolb & Wirshaw H9

Answer 1

Computer-geassisteerde apparaten ontwikkelt om biologisch functioneren te vervangen.

Question 2

Motor cortex

Kolb & Wirshaw H9

Answer 2

Gehele zenuwstelsel, bestaat uit verschillende delen:
1. Brainstem and spinal cord = movements
2. Basal ganglia = force
3. Motor neurons
4. Cerebellum = accuracy

(plaatje)

Question 3

Neocortex

Kolb & Wirshaw H9

Answer 3

Bewegingen initieren, bestaat uit 4 neocorticale gebieden:
1. Posterior cortex
2. prefrontal cortex (PFC)
3. premotorcortex
4. primary cortex

Question 4

Neocortex

Posterior cortex

Kolb & Wirshaw H9

Answer 4

Ligt achter central fissure (lijn).
- Specificeert bewegingsdoelen
- stuurt sensorische info naar frontale gebieden via verschillende routes.
* Directe route: gaan naar primaire motorcortex om bewegingen uit te voeren.
* Indirecte route: door de temporale en frontale cortex voor bewuste controle.

Question 5

Neocortex

Prefrontale cortex

Kolb & Wirshaw H9

Answer 5

Genereert plannen voor bewegingen die het doorgeeft aan de premotor- en motorcortex.

Question 6

neocortex

Premotorcortex

Kolb & Wirshaw H9

Answer 6

Herbergt een bewegingsreportoire (lexicon) die o.a. andermans bewegingen herkent en soortgelijke of andere acties selecteert. Het premotorgebied bevat een ventraal en dorsaal gebied genaamd de supplementaire motorcortex.

Question 7

Neocortex

Primaire motorcortex (M1)

Kolb & Wishaw H9

Answer 7

Bestaat uit meer elementaire bewegingen dan het premotorlexicon, zoals hand- en mondbewegingen.

Question 8

What are the 2 routes when a movement goals arises?

Kolb & Wishaw H9

Answer 8

If movement is simple= premotor and motor cortex.

If planning is required= temporal and prefrontal cortices make decisions –> and then the premotor and motor cortices execute the appropriate movements.

Question 9

Mapping motor cortex using electrical stimulation

Kolb & Wishaw H9

Answer 9

Penfield
We rely primarily on our hands for manipulating objects, but can do is also with other parts of the body if we have to.

Most movements were triggered by stimulation of the primary cortex, M1. Movements can result from stimulation of the dorsal part of the premotor cortex, sot his is the supplementary motor cortex.

Homonculus: rare kleine mens die door de grootte van elk lichaamsdeel laat zien hoeveel precieze motor control deze hebben. PLAATJE

Question 10

Multiple representations in the motor cortex

Kolb & Wishaw H9

Answer 10

A refinement showed many more homunculi, there may be 10 homunculi within the motor and premotor corticesm and parts of the homunculi are not arranged as simply as Penfield sketched them.
2 categories:
1. Natural movement categories
2. Visual-parietal-motor connections

Question 11

Multiple representations in the motor cortex

Natural movement categories

Kolb & Wishaw H9

Answer 11

Micheal Graziano
Electrical stimulation elicits actions that’s called “ethological categories of movement”: because these are the movements that the monkey uses in its everyday activities.

The primary motor, premotor cortex and PFC all have different movement categories. There are many cortical maps of the body, but each map reflects a different action, each area reflects 3 types of organization:
1. The body part that needs to move
2. The spatial location to which the movement is directed
3. The function of the movement

Question 12

What is the similarity between Penfield and Granziano?

Kolb & Wishaw H9

3 punten + extra ding :) en hij hoort niet geel te zijn want je kent m nog niet

Answer 12

That:
- Whole-body movements are located in the dorsal premotor cortex,
- hand movements of reaching are located more ventrally, and
- hand movements to the mouth are located in the most ventral part of premotor cortex.

Whole body movements are represented in the premotor cortex and more discrete movements in the motor cortex.

Question 13

Multiple representations in the motor cortex

Visual-parietal-motor connections

Kolb & Wishaw H9

Answer 13

Each cortical motor region makes a different contribution to movement:
- The visual cortex identifies the spatial location of the target and its shape
- The parietal cortex identifies the body part that will contact the object.
- The motor cortex represents the elements required to move the arm to the target and shape the digits to grasp it.

The connections from the visual cortex to the parietal cortex to the motor cortex form a dual pathway that causes the action of grasping the target.

Cortex identifies the target, brainstem and spinal cord orchestrate the movement.

Question 14

Movement lexicon

Kolb & Wishaw H9

Answer 14

Graziano’s mapping supports the view that humans have lexicon/reportoir of movement categories in the cortex.

Question 15

What is evidence for movement lexicon?

Kolb & Wishaw H9

Answer 15

1. To pick up small objects, humans adopt a pincer grip, often with the thumb and index finger. Most primate species use this same grip pattern.
2. After small lesion in which the pincer grip is lost, a person is likely to substituse a new movement, a whole-hand grip. Apparently then, the pincer grip and other skilled movements are not entirely learned but are part of the vocabulary in a prewired movement lexicon.

Question 16

How are lexicons encoded?

Kolb & Wishaw H9

Answer 16

Lexicons are encoded in the neural connections as basic movement patterns.

Premotor cortex plays a greater role in organizing whole body movements than M1(primary cortex), which controls specific acts.

VB: healthy monkey can pass a nut through a hole with one hand and catch with the other hand. Injury monkey to premotor cortex can still pass nut through hole and open palm of hand to catch, but can’t link these actions together.

Question 17

Mirror neurons

Kolb & Wishaw H9

Answer 17

Mirror neurons in the ventral premotor region discharge when someone makes a movement themselves, as well as when you see someone making the same movement.

Mirror neurons respond to actions that acquire target objects and can control Brain-Computer Interfaces (BCIs).

Question 18

Mirror neurons theory

Kolb & Wishaw H9

Answer 18

Suggests that we understand our own actions and those of others by internally replicating the movements we would use to produce that action.

The ability of mirror neurons to participate in self-action as well as in perceiving others’ actions suggests that they form the neural substrate for:
- self awareness
- social awareness
- awareness of intention and action in others

and they are likely important for gestural and verbal language.

Dysfunction in mirror neurons: could cause less empathy in a person.

Question 19

Motorcontrol

The brainstem

Kolb & Wishaw H9

Answer 19

There are about 26 pathways to the spinal cord that originate in various brainstem locations. These send info pertaining to posture and balance, and they control the autonomic nervous system.

Brainstem is also important in:
- Movements used in eating and drinking and sexual behaviour.
- Posure (stand upreight)
- Making coordinated movements of the limbs
- Swimming, walking
- Movements used in grooming and making nests

Question 20

Welke gebieden worden verbonden door de Basal Ganglia?

Kolb & Wishaw H9

Answer 20

Basal ganglia (collection of subcortical nuclei in the forebrain) connects the motor cortex with the midbrain

and connects the sensory regions of the neocortex with the motor cortex.

Question 21

Basal Ganglia

Caudate putamen

Kolb & Wishaw H9

Answer 21

Is a large cluster of nuclei located beneath the frontal cortex.

A part of the caudate extends as a tail into the temporal lobe and ends in the amygdala.

(Google: het doorgeven van allerlei sensorische info over de ruimtelijke positie van het lichaam)

Question 22

The basal ganglia receive inputs from two main sources:

Kolb & Wishaw H9

Answer 22

1. All areas of the neocortex and limbic cortex, including the motor cortex, project to the basal ganglia.
2. The nigrostriatal dopamine pathway extends into the basal ganglia from the substantia nigra, a cluster of darkly pigmented cells in the midbrain.

Question 23

What are the two types of movement disorders that come from injury to the basal ganglia?

Kolb & Wishaw H9

Answer 23

1. Huntington’s disease: the cells from the caudate putamen are damaged causing unwanted choreiform (involuntary and exaggerated) movements, dyskinesia. Involuntary movements occus in involuntary tics and voculizations as in Tourette’s.
2. Parkinson’s disease: is caused by the loss of dopamine cells from the substantia nigra and of their input into the basal ganglia via the nigrostriatal pathway. The cells of the basal ganglia are intact, but the input is damaged making movements difficult (hypokinetic)

These two opposing sets of symptoms (hyper- hypokinetic) that occur after basal ganglia damage suggest that one of its major functions is to modulate movement.

Question 24

Basal ganglia circuits affect motor cortex activity through two pathways

Kolb & Wishaw H9

Answer 24

1. Inhibitory pathway (direct) https://www.youtube.com/watch?v=c-mhDChCD4Y
2. Excitatory pathway (indirect) https://www.youtube.com/watch?v=RzcXkvxXKEQ

PLAATJE

The two pathways converge on an area of the basal ganglia called the internal part of the globus pallidus (GPi).
- The GPi projects to the thalamus, 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.

So if activity in the excitatory pathway is high compared to the inhibitory pathway, excitation of the GPi will predominate and inhibit the thalamus, reducing input to the cortex, and so will power. The same applies the other way around.

The technique of stimulating the GPi or other structures in the basal ganglia circuitry with deep brain stimulation is one treatment for the rigidity in pat’s with Parkinson’s disease.

Question 25

Cerebellum and motor learning

Kolb & Wishaw H9

Answer 25

Cerebellum seems to be the motor system component that participates in acquiring and maintaining motor skills. It sits atop the brainstem and is clearly visible just behind and beneath the cerebral cortex, it also has two hemispheres.

A small lobe calles the flocculus projects from its ventral surface.

Question 26

In which regions is the cerebellum divided?

Kolb & Wishaw H9

Answer 26

Medial areas = associated with the face and body’s midline.

More lateral areas = associated with movements of the limbs, hands, feet and digits.

Question 27

Damage in the cerebellum

Kolb & Wishaw H9

Answer 27

• Damage in midline areas: disrupt balance, eye movements, upright posture and walking, but don’t disrupt other movements.
• Damage to lateral parts: disrupts arm, finger, hand movements far more than movements of the body’s trunk.

Question 28

How the cerebellum controls movements center on two major ideas:

Kolb & Wishaw H9

Answer 28

1. It has a role in movement timing. The underlying impediment in cerebellar dysfunction is a loss of timing, both in movement and perception.
2. It helps maintain movement accuracy. Trial-and-error actions include the cerebellum.

In addition to its role in motor learning, the cerebellum participates in coupling movements, so the flow of action appears seemless.
VB: when we reach for an object, we seemlessly combine two movements, a reach and a grasp