Topic 4 Action pt 1

Question 1

What is action?

Answer 1

• change the environment
• somatic (skeletal mm moves limbs)
• autonomic
• internal to CNS

Question 2

What is an example of internal action to CNS

Answer 2

updating memory: holding a phone number in our minds and then updating it to change it to the right phone number
switching tasks: studying one subject then studying another subject right after

Question 3

What is the problem with action and why is this important?

Answer 3

problem: how to effect change in the world
importance: necessary to achieve goals (eat, drink, reproduce, survive)

Question 4

Action: inverse problems

Answer 4

planning which actions to take in order to achieve goals

Question 5

inverse model

Answer 5

• current position and desired position
• > motor command
• used to create motor plan

Question 6

used to create motor plan

Answer 6

inverse model

Question 7

forward model

Answer 7

• current position and motor command
• > predicted position
• used to evaluate motor plan and/or action

Question 8

Carson is playing the piano. Which part of the brain is he using the most to do these movements?

Answer 8

supplementary motor cortex

Question 9

feedforward control uses ______

Answer 9

feedforward model uses inverse model

Question 10

feedback model uses ______

Answer 10

feedback model uses both inverse model (because it has a feedforward controller) as well as the forward model (because it uses comparator)

Question 11

what part of the brain is responsible for initiation and termination of movement

Answer 11

basal ganglia

Question 12

actuator

Answer 12

to cause something to operate or to activate something (muscles)

Question 13

Which homunculus has bigger area for the hand? somatosensory or motor?

Answer 13

motor

Question 14

how does using top down and bottom up processing help?

Answer 14

probably helps speed things up

Question 15

function of brainstem centers

Answer 15

basic movements and postural control

Question 16

Supplementary motor cortex is ____ to primary motor cortex and ______ to premotor cortex

Answer 16

Supplementary motor cortex is rostral to primary motor cortex and dorsal to premotor cortex

Question 17

What is it called when we are able to write the same sentence despite using different mm groups?

Answer 17

motor equivalence

Question 18

current position and desired conditions

-> motor command

Answer 18

inverse model

Question 19

current position and motor command

-> predicted position

Answer 19

forward model

Question 20

efference copy

Answer 20

internal copy of a motor command

Question 21

Faster but less accurate (feedforward or feedback control?)

Answer 21

feedforward control

Question 22

feedback control (4 points)

Answer 22

• motor control sent to mm
• actual state compared to desired state
• adjustments made based on errors
• slower, but more accurate

Question 23

feedforward control (2 points)

Answer 23

• motor command sent to mm

- faster, but less accurate

Question 24

Quench thirst

Answer 24

goal

Question 25

drink from cup

Answer 25

conceptual level

Question 26

pick up cup from right hand

Answer 26

effector level

Question 27

activate appropriate mm in arm

Answer 27

implementation level (actuator is mm)

Question 28

supplementary motor cortex

Answer 28

- involved in selecting goals and planning actions at a conceptual level - particularly when plans involve internally generated sequence of actions - keeps track of where we are in the sequence

Question 29

peristimulus time histogram

Answer 29

shows action potentials during individual trials as well as histogram of action potential firings over time (recordings from SMA allows us to know that neurons fire in anticipation of a sequence of events)

Question 30

When do neurons fire in the SMA?

Answer 30

- some neurons fire in anticipation of a sequence - some neurons fire in anticipation of a particular action in a particular sequence - some neurons fire in anticipation of the next particular action (could be any action, such as the 3rd action of any sequence of movement)

Question 31

what does injecting muscimol do to the SMA?

Answer 31

- GABA agonist to manipulate SMA - animal trained to already do particular sequence of actions is injected with muscimol to SMA - injecting muscimol turns off this brain area temporarily

Question 32

What happened to the primates ability to do a learned sequence when their SMA was inhibited ?

Answer 32

Although the primates could still do cued sequences, the primates made a lot of mistakes when they were asked to do a learned sequence

Question 33

True or False: The motor cortex represents specific mm actions

Answer 33

false: the motor cortex represents directional movements of body parts, not the specific mm actions

Question 34

Signals from motor cortex travel directly to ____

Answer 34

signals from motor cortex travel directly to lower motor neurons and lower circuit in the brainstem and spinal cord

Question 35

motor cortex activity is related to ____

Answer 35

movement direction

Question 36

response rate as a function of direction of movement can be summarized by a

Answer 36

tuning curve

Question 37

In a population vector, what does the length of the arrow mean?

Answer 37

long arrow: relative rate of firing increases, increase intensity short arrow: relative rate of firing decreases, decrease intensity

Question 38

population vector

Answer 38

accurately represents actual movement direction

Question 39

do population vectors represent the action has been taken?

Answer 39

no, population vectors are plans of the movement. first we are given a cue, then neurons fire (population vector), then the "go" signal is given

Question 40

basal ganglia function

Answer 40

- help select, initiate, and inhibit movements through cortico-basal-ganglia-thalamocortical loops - dopamine based reinforcement learning - participate in motor control, cognitive control, and emotional control

Question 41

Direct pathway

Answer 41

- Cortex - striatum - GPi/SNr - Thalamus - Cortex

Question 42

Indirect pathway

Answer 42

- Cortex - Striatum - GPe - STN (subthalamic nucleus) - GPi/SNr - Thalamus - Cortex

Question 43

Hyperdirect pathway

Answer 43

- Motor cortex - STN - Thalamus - Cortex

Question 44

Where is the dopamine signal coming from?

Answer 44

substantia nigra pars compacta

Question 45

The _____ is activated by external stimuli whereas the _____ is moreso activated by internal stimuli (sequence)

Answer 45

The premotor cortex is more activated by external stimuli whereas the SMA is more activated by the internal stimuli

Question 46

what is reponsible for reflex coordination?

Answer 46

local circuit neurons (interneurons in the spinal cord)

Question 47

the striatum (inhibits, excites) _____ the _______ via the indirect pathway and (inhibits, Excites)_______ the ________ via the direct pathway

Answer 47

the striatum inhibits the GPe in the indirect pathway and inhibits the GPi/SNR via the direct pathway