Topic 4: Action

Question 1

Somatic action

Answer 1

skeletal muscles (like moving a limb)

Question 2

Autonomic action

Answer 2

smooth muscles, cardiac muscles, endocrine glands, and exocrine glands

Question 3

Action in CNS

Answer 3

update memory, switch tasks, etc.

Question 4

The inverse problem

Answer 4

determining what actions to take in order to achieve goals

Question 5

the supplementary motor cortex is more ____ than the premotor cortex (lateral/medial)

Answer 5

medial

Question 6

the primary motor cortex is more ____ to the supplementary motor cortex (rostral/dorsal)

Answer 6

dorsal

Question 7

Inverse vs. Forward models

Answer 7

Inverse: current position and desired position –> creating motor commands

Forward: current position and motor comments –> predicted position (evaluating motor plans)

Question 8

Efference copy

Answer 8

Internal copy of a motor command

Question 9

Feedforward control

Answer 9

motor command sent to muscle; faster but less accurate

Question 10

feedback control

Answer 10

motor command sent to muscle; actual state compared to desired state; adjustments based on errors; slower, but more accurate

Question 11

would a feedforward controller use a forward model or an inverse model

Answer 11

inverse

Question 12

How is the premotor cortex involved in motor planning?

Answer 12

selecting goals and planning actions at a conceptual level, particularly when plans are driven by external stimuli; happens before voluntary movement

Question 13

Monkey alternative actions study (what happened, what did it show?)

Answer 13

monkey is cued by two spatial cues of the two possible targets, they cues are removed, monkey is cued with actual target and prepares single action, go signal and monkey initiates action

premotor neurons for the arm were active and planning the movement before it happened

Question 14

mirror neurons

Answer 14

a neuron in the frontal or parietal cortex that shows similar electrophysiological responses to actions executed by oneself or to observation of the same actions being executed by another (conceptual level)

Question 15

Supplementary motor cortex (SMA)

Answer 15

selecting goals and planning actions at a conceptual level (especially with sequences)
- fire in anticipation of a particular sequence

Question 16

what happens to a monkey in a motor task when they have they supplementary motor cortex inhibited?

Answer 16

no longer perform well learned movements and must rely on external cues to tell them which movement should be performed

Question 17

when happens to those with lesions in the premotor cortex?

Answer 17

disrupted visually guided movements, but their ability to commit learned tasks is fine

Question 18

T/F

The motor cortex represents movements of specific muscle actions, not directional movements of body parts

Answer 18

False

• different neurons have different directional sensitivities

Question 19

Tuning Curve

Answer 19

shows the response rate of a neuron based on the direction of movement; can been determined through population vectors

Question 20

Population vectors

Answer 20

adding up all vectors for a neuron from its preferred direction and the length (firing rate)

• shows the actual movement direction
• direction of this predict the direction of a forthcoming movement

Question 21

Define all four Intraparital sulcus spaces (LIP, VIP, MIP, and AIP)

Answer 21

Lateral (LIP): space for eye movements

Ventral (VIP): space for facial movements

Medial (MIP): space for arm

Anterior (AIP): space for hand movements

Question 22

What do the IP areas do?

Answer 22

important role in guiding movements to correct location, orientation, and configuration

Question 23

What are three main things the basal ganglia helps with in motor action?

Answer 23

1. select, initiate, and inhibit movements through cortico-basal ganglia-thalamocortical loops
2. critical to dopamine-based reinforcement learning
3. participate in motor control, cognitive control, and emotional control

Question 24

What is the difference between the direct and indirect pathway of the basal ganglia

Answer 24

the direct pathway goes right from the striatum to the GPi/SNr through a single inhibition; whereas the indirect pathway goes from the striatum, to an inhibition of the GPe, inhibition of the subthalamic nucleus, and thn an activation of the GPi and SNr

Question 25

baseline activation in basal ganglia

Answer 25

inhibiting the thalamus

Question 26

action initiation in basal ganglia

Answer 26

direct pathway, aids in the selection and initiation of action

Question 27

action inhibition in basal ganglia

Answer 27

indirect pathway; closing gate inhibiting additional actions; more steps in indirect make it slower

Question 28

reinforcement learning in basal ganglia

Answer 28

unexpected rewards generate dopamine which excites the direct pathway, and inhibits the indirect, allows modification of behaviour based on reward

Question 29

what happens to coordination when you have a lesion in the cerebellum

Answer 29

can’t make accurate movements

Question 30

what two types of neurons are most prominent in the cerebellum?

Answer 30

granule cells (50 billion.. 75% of neurons in brain) and purkinji cells (~200 000 inputs per cell)

Question 31

Does the cerebellum use a forward or inverse model? Feedback or feedforward?

Answer 31

forward, to predict results of motor commands using the differences between actual results and predicted results; feedback

Question 32

what do axons from the primary motor cortex synapse on?

Answer 32

lower motor neurons and local circuit neurons (interneurons)

Question 33

Central pattern generators

Answer 33

local neurons in the spinal cord can control complex movements and respond to environmental changes even without higher-level input

Question 34

lower motor neurons synapse on…

Answer 34

muscle fibres

Question 35

what happens at a lower motor neuron-muscle fibre synapses?

Answer 35

the release of neurotransmitters cause the muscle fibres to contract, which is then detected by the spindles so they can be sent back to the spinal cord through the dorsal root ganglia

Question 36

areas that are ____ (more/less) specific with finer motor control needs have a smaller number of muscles that it sends its signals to

Answer 36

more

Question 37

brain machine interfaces

Answer 37

an array of microelectrodes is attached to the primary motor cortex that controls arm movement, and a calibration between the robot arm and the neurons allow for the person to control the robot by thinking