Lec 8-10 v 2 Flashcards
What are the peak events in a muscle contraction
- M1
- M2
- M3
what is the M1 wave?
the short latency/loop reflex AKA monosynaptic stretch reflex
How long does it take for the M1 wave to hit?
30ms
what is the M2 wave
the long latency reflex
How long does it take for the M2 wave to hit
50-80ms
which wave hits at 30ms
m1
which wave hits at 50-80ms
M2
what is the M3 wave
the voluntary response
how long does it take for the M3 wave to hit
120-150ms
what wave hits at 120-150ms
M3
Which waves are sensitive to goals
M2 and M3
describe the muscle spindle characteristics
- spindle shaped receptor
- parallel to muscle fibers
- hooks up to 1a afferents
- sensitive to changes in length and rate of change
what is the muscle spindle sensitive to
changes in the length of muscle and its rate of change
what receptor is sensitive to muscle length changes
muscle spindle
what structures are involved in the M1 wave
spindles and muscles
what structures are involved in the M2 wave
spindles, cortex/cerebellum, muscle
what structures are involved in the M3 wave
many receptors, brain centres, muscles
what wave(s) involve only the agonist muscle
M1 and M2
what wave(s) involve the antagonist muscle
M3
What are GTO?
GTO: golgi tendon organ
- located in between muscle and tendons
- detect changes in muscle tension
what receptor detects changes in muscle force/tension
GTO
describe the loop of proprioceptive reflexive closed loop control
what can we break down the effector component into
motor program, spinal cord and muscle
what do spindles act on?
motor program, spinal cord and muscle
what do GTOs act on
spinal cord, muscles?
what is the vestibular apparatus
it is the system in the inner ear important for balance and proprioception
what do the semicircular canals detect
angular accceleration
what do the otolith organs detect
linear acceleration
what are joint receptors
receptors within joint capsules that relay important information about joint range limits and pressure
how is vision conscious?
it can go from exteroceptive feedback straight to the input at higher brain centres
how is vision reflexive
vision can go from exteroceptive feedback to the motor program directly
what is the dorsal stream of consciousness
- non conscious, fast
- back of head to the top
- important for navigation
- involves the entire vision field
- important for minor adjustments
which visual stream of processing is fast
dorsal
which visual stream of processing involves the entire vision field
dorsal
which visual processing stream is important for navigation
dorsal
what are the problems associated with dorsal stream
optic ataxia
what is optic ataxia
a visual issue that results from a mismatch in what we see and what we do?? causes patients to miss objects when they move
Which visual problem goes away when you turn the lights off
optic ataxia
what is the ventral stream of processing like
-conscious and slow
- goes from back of head to down
- good for object/stimulus identification
what are the problems associated with ventral processing
visual form agnosia
what is visual form agnosia
it is the inability to identify an object, unless it is moving.
how do we know there are two streams of visual processing?
- dissociations in injuries
- dissociations in illusions
what is the ebbinghaus illusion
it is the illusion that the sizes of objects might appear different but are physically identical, dependent on the relative size next to other objects
what is some evidence for fast vision (dorsal) regulation of motor control
- avoidance/navigation
- balance control
how does avoidance and navigation offer evidence for dorsal processing
as an object approaches, its rate of expansion on the retina causes a reaction without going through the executive
describe how balance control is evidence for dorsal regulation
in the swinging room experiment, we end up counteracting perceived movements with our own, even though we are not aware of it.
what happens in the swinging room experiment if the room swings towards you
you fall bakcwards
what happens in the swinging room if the room moves away from the baby
they fall forwards
what is the mcgurk effect
the illusion where what you hear does not match what you see
what are the two types of closed loop control
- conscious
- nonconscious
describe conscious closed loop control
ventral vision
- conscious
- requires selective attention
- flexible
- slow
describe unconscious closed loop control
dorsal
- little to no conscious control
- reflexive
- inflexible
- rapid
How can someone like ian waterman make limb movements?
he uses open loop control to structure and plan movements in advance, since he wasn’t able to take in any feedback
what is a motor program
motor program: a pre-structured set of neural commands organized in advance, capable of producing movement without feedback
where are movement representations stored
memory
what kind of movements use open loop control
discrete, fast, gross and closed environments
where is the motor program sent to
effectors
what connects the executive and the effector systems
motor program
where is the motor program prepared in
LTM
what are the main pieces of supporting evidence for the existence of GMP
- Movement complexity
- Inhibiting anticipatory actions
- Triphasic EMG pattern + movement blocking
- Startle effect
describe how movement complexity is evidence for the existence of motor prorgams
RT increases with movement complexity?
describe how inhibiting anticipatory actions is evidence for motor programs
once sent, we can’t stop it. there is a point of no return where once the motor program is initiated, the action is carried out.
what do we mean by a prepackaged action/couple units
prepackaged action means that an entire action has smaller movements within it that appear together. coupled units are these small movements that always appear with each other, like a step and swing in baseball
how can we adjust the point of no return to be more accurate
add the CE
after the PONR, which loop is used for movement
open loop
describe how triphasic patterns are evidence for motor programs
i think the pattern remains the same, even if the movement is blocked.
describe how startle effects are evidence for motor programs
startle stimuli can result in a startle response that releases a prepared movement, with a reduced RT
how loud does an acoustic stimulus have to be for it to have a startle effect
90db
how early do we see a startle response
50-70ms
how does the startle effect alter premotor RT? compare it to normal
normal = 95ms, startle = 64ms
what are motor programs synonymous with
open loop control
what are the pros of motor programs
- good for fast actions, since you dont need to wait for feedback
- many degrees of freedom
define degree of freedom
how many degrees of freedom in shoulder joint, elbow joint, radio ulnar joint and wrist joint
shoulder joint = 3
elbow joint = 2
radio-ulnar joint = 1
wrist joint = 2
what are the cons of motor programs
- storage problem
- novelty problem
how do we solve the cons of motor programs
we use general motor programs
define GMP
GMP: memory of a class of actions that can be modified/tuned for a desired output
what are the components of GMP
- invariant feature
- parameter
what solves the storage problem of mp
invariant features
what solves the novelty problem of mp
parameters
what problem do invariant features solve
storage problem
what problem do parameters solve
novely problems
define invariant feature
invariant feature: fixed features that define the motor program
define parameter
parameter: flexible features that define how the motor program will be executed
what happens with invariant features and parameters in response selection
invariant features and parameters selected
what happens with invariant and parameters in response programming
parameters are assigned to the GMP
what is some evidence for GMP existence (class)
writing your signature with different hands/backwards etc - relatively similar but all slightly modified
how do we identify GMP
invariant features
1. relative timing
2. relative force
3. order of events
which identity of the GMP is the most critical
relative timing
what is relative timing
the internal rhythm of a skill - the relative timing of actions is invariant/fixed, and remains constant.
describe relative force as an identity of GMP
The force produced by muscles remains constant in proportion from movement to movement
describe how order of events is an identity of GMP
the order remains fixed, and is important for success of movement. muscle #1 will be active before #2
what are the types of parameters
- absolute duration
- absolute force
- muscle selection (effectors)
how is movement time a feature of parameters
absolute duration can change, but the relative timing remains the same
describe how movement amplitude is a type of parameter
the absolute force of movement can be altered, but the relative force will remain the same
what is schema
memory, or the relation between outcomes and parameters
describe how muscle selection is a factor of parameters
the muscle selection can vary - we can select different muscles for the same program depending on the context
