Brain anatomy 3

Question 1

By which 2 tracts is the voluntary movement governed?

Answer 1

the pyramidal tract and the extrapyramidal tract

Question 2

Which structures are involved in volitive movement behaviour?

Answer 2

-primary motor cortex
- association motor cortices
- basal ganglia
- cerebellum
- spinal cord

Question 3

Which cortices are involved in the descending pathway and which in the ascending pathway?

Answer 3

The primary motor M1 emerges into the descending pathway and from the primary somatic S1 the ascending (incoming) patway ends

Question 4

What is the role of M1, the primary motor cortex which resides in the pre-central gyrus?

Answer 4

its role is planning and initiating the voluntary motor behaviour.

Question 5

What does the PMC premotor cortex do?

Answer 5

It supports M1, sensory guidance of moving controlling most proximal and trunk muscles.

Question 6

What does PPT do? posteroparietal motor pathway

Answer 6

Transform visual info in motor commands

Question 7

What is the role of SMA (supplementary motor)?

Answer 7

Two-hanf coordination and complex motor planning

Question 8

What is the role of S2?

Answer 8

Remember difference between tactile shape and texture of an object

Question 9

How does M1 communicate to plan and initiate motor behaviour?

Answer 9

from M1 axons from pyramidal neurons
depart and never stop until they have reached the spinal cord associated to a particular part of the body! No extra synapses in between!! This ride toward the spinal cord is called cortical-spinal tract and usually, emerging from the M1, it firstly converges in the so-called corona radiata, to then walk through the internal capsule, all the way through the cerebral peduncles (the highways to the spinal cord) and to the pyramid in the myelencephalon.We have the decussation of the fibers, so that left hemisphere axons then will go to target the right part of the spinal cord and the other way around.

Question 10

How are the fibers called that do cross-over for the motor command from m1 and how are the fibers called that don’t?

Answer 10

The fibers that do cross-over form the so-called lateral corticospinal tract and the fibers that don’t cross-over are called the ventral corticospinal tract

Question 11

What is the difference between the lateral corticospinal tract and the ventral corticospinal tract?

Answer 11

The lateral corticospinal tract does cross-over and is used for more distal muscles and the ventral corticospinal tract does not cross-over and is used for the more proximal muscles

Question 12

Which tract is used for the movement of the head and the neck?

Answer 12

the corticobulbar tract, it goes from m1 to the pons and mesencephalon where we find many nuclei for cranial nerves.

Question 13

What is the difference between fine touch and the pain pathway?

Answer 13

In the fine touch pathway, the dorsal column-medial lemniscus pathway is used which travels from the spinal cord to the thalamus. In the pain pathway, the anterolateral pathway is used. This pathway decussates immediatly and goes all the way via the spinal cord to the thalamus. So, the first one decussated later on and the latter one will decussate immediatly.

Question 14

The basal ganglia does or does not project to the spinal cord?

Answer 14

The basal ganglia does not project to the spinal cord

Question 15

Who are the advisors of M1?

Answer 15

The basal ganglia

Question 16

Name the names of the basal ganglia in the telencephalon, diencephalon, and the mesencephalon.

Answer 16

telencephalon:
- dorsal striatum (caudate and putamen)
- globus pallidum (GP)
diencephalon:
- subthalamic nucleus (sub-thal)
mesencephalon:
-substantia nigra (SN)

Question 17

What are the 5 main functions of the basal ganglia?

Answer 17

• initiation of movement
• movement scaling
• movement sequencing
• switching movement
• selection/ inhibition of competing motor prog.

Question 18

What is the role of the basal ganglia in motor movement?

Answer 18

It supports the M1 to decide which movement is more appropiate: the switch between sensitive and pain

Question 19

Describe the difference between the direct and the indirect pathway of the basal ganglia and m1

Answer 19

The direct pathway goes directly to the thalamus and the indirect pathway stops at the subthalamic nucleus before going to the thalamus. The direct patway will disinhibit M1 and the indirect patway will inhibit M1

Question 20

Who decides which pathway is going to get activated (indirect or direct motor pathway)?

Answer 20

The SN par compacta, a nest of mesencephalic dopamine neurons which send projections to the putamen and due to the modulatory role of dopamine can stimulate the direct pathway and at the same time inhibit the indirect pathway. So, it is in favour of disinhibiting M1, so not inhibited

Question 21

What is the function of the cerebellum?

Answer 21

It is important for motor functions and is the master of fine coordiantion. It prevents us to fall and allows us to produce elaborate movements with grace. It is also involved in cognition and speech, attention and balance

Question 22

In which 3 functions is the cerebellum subdivided?

Answer 22

1. archicerebellum
2. paleocerebellum
3. cerebrocerebellum

Question 23

What are the functions of each of the parts of the cerebellum? archicerebellum, paleocerebellum, cerebrocerebellum

Answer 23

• archi: balance and coordination
• paleo: integrating sensory inputs with motot commands
• cerebro: cognitive functions such as spech coordination, attention)

Question 24

What is the role of the limbic system?

Answer 24

An important group of regions
that spans through a big part of the telencephalon and, to a certain extent also the mesencephalon, makes up the so-called limbic system. It is responsible for emotional expression and emotional control

Question 25

What is the role of the hippocampus?

Answer 25

It is the place for long-term memory consolidation.

Question 26

What are the regions called that add up to be the hippocampus?

Answer 26

• The Ammon’s horn
• dentate gyrus
• subiculum
• pre and parasubiculum
• entorhinal cortex
• parahippocampal gyrus

Question 27

Which regions in the hippocampus are directly involved in reinforcing of long-term memories?

Answer 27

The projections from the CA3 to the CA1

Question 28

How does the hippocampus communicate with the rest of the body?

Answer 28

Via the fornix, a white matter bundle of fibers that terminates in the mammalian bodies

Question 29

What is the role of the amygdala?

Answer 29

It is involved in emotion expression (the centro-medial amygdala) and fear (the basolateral amygdala)

Question 30

What happens when you don’t have a BLA (basolateral amygdala)?

Answer 30

You have no fear

Question 31

Where are procedural tasks stored? (riding your bike)

Answer 31

This is a cerebellar task. The hippocampus does not store memories, it makes them long-term viable.

Question 32

Describe the different roles of the cortices

Answer 32

The primary cortices sucha s m1 or s1 are involved in either motor or sensory functions on a very basic level (employees working in a call centre)
Areas in the neocortex associate only with one type of information (supervisors)
The heteromodal association cortices integrate information from different modules (big manager) often based on previous experience (memory)

Question 33

Name an example of a heteromodal cortex that integrate information from memories

Answer 33

the (pre) frontal cortex

Question 34

What is the role of the PFC (prefrontal cortex)?

Answer 34

It plays a crucial role in decision making, high cognitive functions and executive functions. (memories)