1-7 Flashcards
What are the 3 pre-requisites of motor skills?
- limb/head movement
- voluntary
- purpose/goal
How are degrees of freedom determined
by the number of joints within a rigid body
How are degrees of freedom reduced
- development of muscle synergies/coordination
- physical properties
- comfort
How does the development of muscle synergies reduce degrees of freedom
Body becomes rigid, reducing the DOF available (e.g linking upper and lower arm reduces uniqueness and DOF)
Gross vs Fine motor skill
large muscles - gross
small muscles - fine
Discrete vs Serial vs Continuous motor skills
discrete - not repetitive (e.g jumping)
serial - a series of discrete movements (e.g playing a piano)
continuous - a continuous cycle of movement (e.g rowing, running)
Closed vs Open motor skills
closed - no need to adapt to environment (e.g swimming in a lane)
open - adapting to the environment (e.g swimming in an ocean)
Study Gentiles 2 Dimensional Classification
lecture 2.1
Types of Reaction Time
Simple - only one option (e.g pressing a button)
Choice - given a choice based on stimulus (e.g pressing a button asap with the right hand for the right light and the left hand for the left light). Hicks Law
Discrimination - making a decision (e.g pressing a button asap when a certain coloured light is turned on, but not when others are displayed)
What is fractionated reaction time
Premotor Time + Motor Time = Reaction Time
What is premotor time?
The time taken for the brain to recruit muscle fibres in response to a stimulus (time taken from appearance of stimulus to the first visible EMG trace)
what is motor time?
movement hasn’t started but the muscle is already firing
What is the speed-accuracy trade off referred to as?
Fitts Law
What is a choice reaction time referred to as?
Hicks Law
What are some variables that influence reaction time?
- Response selection
- Response programming
- Response complexity
- Accuracy demands
- Genetic disorders
- Age
What is constant error?
average error of performance
a CE of -0.8 means they shot 0.8 units too short of the target
What is variable error?
how consistent their performance is
A VE of 0.8 means the results were on average 0.8m apart from one another
What is total error?
Constant error + variable error
Negatives don’t count. e.g CE of -1, VE 0.4, TE = 1.4
What are the 4 major paradigms in motor control research
- Ideomotor
- Behaviourism
- Cognitivism
- Holism
What is the ideomotor paradigm
movements are initatid without active intent and influenced by images and ideas
What is the behaviourism paradigm
behaviours are either a reflex or a consequence of history
What is the cognitivism paradigm
brain is seen as a computer with an input and output
What is the holism paradigm
everything works in tandem with one another
What are the 3 major theories in motor control research?
- reflex theories
- hierarchical theories
- dynamical/ecological theories
What are the main ideas of the reflex theory
- Muscle reflexes are the basis of all movement
- Use afferent information
- External stimulus leads to a movement, which leads to a new stimulus to trigger a new movement (response chaining hypothesis)
What are the main ideas of the hierarchical theory
Top down control. The cerebral cortex controls the systems below
What are the main ideas of the dynamical systems theory
The system is capable of self organisation and the brain doesn’t have to make a decision for every movement or behaviour, but creates patterns instead
What is the order of hierarchy within the body
- Premotor and supplementary motor control
- Motor cortex
- Brainstem
- Spinal cord
- Peripheral nerves
- Muscles
What is the difference between hierarchical and reflex theories
Reflex theory is where the body moves in response to stimuli
Hierarchical theory is where the brain is responsible for the planning and execution of movement
What are the main ideas of the ecological dynamics theory
Interaction between human and environment
What is self organisation
The body creates its own movement patterns
Does open loop control have feedback?
No
Does closed loop control have feedback?
Yes
What theory is motor programs a branch of?
hierarchical
How fast does a movement have to be to not apply feedback according to the motor program theory
Less than 150-200ms
What was Schmidt’s Generalised Motor Program?
all movement is stored as a generalised motor program. Some features were variable (absolute timing, absolute forces, muscle selection) and others were invariable (sequencing, relative timing, relative forces)
Limitations of Schmidt’s generalised motor program
cannot explain
- optical flow
- affordances (different possibilities for actions within the same environment)
- time to contact
- self organising systems
What are the 5 steps of motor planning and execution
- Input
- Deciding to act (limbic system)
- Response selection (association cortex)
- Scaling/fine tuning (projection system)
- Execution (spinal system)
- Feedback (spinal system)
What is the role of the Basal Ganglia in motor planning?
preparation and scaling
What are the 4 lobes of the cerebral cortex
- Motor cortex
- Pre-motor cortex
- Supplementary motor area
- Parietal cortex
What is the role of the spinal cord in motor control
carry efferent and afferent information
What is efferent
Away from the brain
What is afferent
To the brain
Why does the left side of the brain control the right side of the body (and vice versa)
75% of the neurons on the right side of the brain switch over to the left side in the medulla (and vice versa)
The other 25% don’t cross sides and control axial muscles (spine, core etc.)
Muscle spindle receptors
- Spindles fire when muscle stretched
- 1a afferent
- Gamma motor neurone carry neural impulse from CNS to muscle spindles
- When pre-planning a movement, spindles will become less sensitive as the body is already aware of a movement that is about to occur
Golgi Tendon Organs
- Give feedback to tendon stretch
- 1b afferent
- Allow us to estimate weights of objects and forces applied to objects
Joint receptors
- Sensory endings in the joints
- Provide information of the joint angle (e.g knowing the position of a joint when in the dark/can’t see)
Cutaneous receptors
- Receptors in the skin
- Mechanoreceptors measure deformation of skin e.g information about touch, pressure
- Homunculus. As the hands are overrepresented with cutaneous receptors
What are the 4 types of proprioceptors (peripheral nervous system)
- Muscle spindles
- Golgi Tendon Organs
- Joint receptors
- Cutaneous receptors
Is a muscle stretch reflex a short or long reflex loop
Short
What are the three main groups of sensory receptors
- Interoceptors
- Proprioceptors
- Exteroceptors
What type of information do exteroceptors provide
visual and audio
What is the role of the vestibular system in proprioception
Signal balance (position and movement of the head)
What is the pathway of sensory information
Spinal Nerves –> Spinal Column –> Thalamus –> Primary Somatosensory Cortex –> Association Areas
What does the primary somatosensory cortex do?
Signals generated from the proprioceptors are considered to be be ‘just a signal’. At the PSC, signals are translated to detect what the signal was.
What do association areas do?
They receive translated signals from the primary somatosensory cortex and create relevant motor responses from them
What are the 5 types of eye movement
- Vestibular-Occular Reflex
- Optokinetic Reflex
- Smooth Pursuit
- Saccades
- Vergence
What is the Vestibular-Ocular Reflex eye movement
stabilises eye when head moves
What is optokinetic reflex eye movement
maintains stable image on retina
What is smooth pursuit eye movement
track slow moving objects in space
What is saccades eye movement
eyes jump to track fast objects
What is vergence eye movement
brings objects at different depths of focus
What is event occlusion
A section of visual information is masked, and a participant has to predict the outcome of the movement. e.g masking a section of a tennis serve (masking the feet, racquet arm, non racquet arm etc.) and seeing if the receiver can predict where the ball is going to go
Why are 2 eyes better than one
depth perception
What is the 2 visual stream hypothesis?
light absorbed from the eyes are transferred into a visual signal which is sent to the primary cortex, and then sending the signal to the ventral and dorsal stream
What is the ventral stream in the 2 visual stream hypothesis
vision for perception. identifying objects
Wha is the dorsal stream in the 2 visual stream hypothesis
vision for action. spatial awareness and guided actions
What is Perception-Action Coupling
The ventral and dorsal streams are coupled and use open loop control instead of a closed loop (e.g gaming)
What is Tau
Time to contact
larger image on retina = closer
Who is effected by postural sway
everyone. no one has a postural sway of 0
Under what conditions does sway increase under
- Closing eyes
- Standing on narrow support
- Age and disorder
What are the three senses for postural stability
Vision
Proprioception
Vestibular
What is Fitt’s law
to maximise speed, accuracy must be reduced
What does a high index of difficulty mean
more difficult to complete a task within the same movement time
What are the 2 phases of motor control processes Related to the Speed-Accuracy Trade-off
Phase 1 - initial rapid limb movement
Phase 2 - homing in
What are the 3 phases in which visual information is used in the speed-accuracy trade-off
- Preparation phase
- Initial flight phase
- Termination phase
How does object manipulation affect prehension
Depending on how your planning on manipulating an object can impact the transport and grasp phases (e.g choosing to put a cup in the dishwasher vs choosing to drink out of it can impact transport and grasp)
What is a symmetrical motor skill?
a skill that requires both hands completing the same task e.g rowing
What is an asymmetrical motor skill
two hands completing two different tasks (e.g playing guitar)
require 2 different motor programs to be launched
What is Hicks law?
reaction time increases in a logarithmic relationship as the number of stimulus-response choices increases
What is priming/pre-cue
Reaction time decreases as the predictability of one of the possible choices increases
What is fore period predictability
the time between a warning signal and the word ‘go’ (e.g take your marks)
if the fore period is always the same length
Is a GTO reflex a short or long reflex loop
Short
What is the difference between a short and long reflex loop
Short - same spinal level
Long - across spinal levels, more complex movements
What are the two types of spinal reflexes?
Long and short reflex loops
What are spinal reflexes
the afferent signal from GTO reflex and muscle stretch reflex (short reflex loops) that project to the spinal cord
What does Fitts Law formula represnt
2D/W (D = movement distance, W = width of object)
What relationship does index of difficulty have
higher ID = more difficult task to complete within the same movement time
What are the 2 phases of fitts law
- initial rapid movement
- homing in
What is motor equivalence
adapting to the demands of the task (adjusting size, force, direction, and muscle involvement)
what is the filter attention theory
bottleneck. Can only do things one at a time. Doesn’t explain multitasking
What attention theory says you can only do one thing at a time
filter attention theory
What is the central resource capacity attention theory
All tasks are located within an attention bubble. By completing multiple activities at a time, it causes the attention bubble to fill up
What attention theory are all tasks located within an attention bubble
central resource capacity theory
What are the 4 types of performance curves
Linear
Negatively Accelerated
Positively Accelerated
Sigmoid Curve
What is a dual task procedure?
Simultaneous execution of two different tasks. Playing table tennis and having to do quick maths
What are methods to assist working memory
chunking, repetition
Difference between implicit and explicit knowledge
Implicit - info we are not aware of (relates to motor skills). Muscle memory
Explicit - info we are constantly aware of. Knowledge, previous experiences
Motor Learning Experiment testing order
- Pre test
- Practice
- Post test
- Retention Interval
- Retention Test
- Transfer test
Vertical Transfer
applying a skill to a more complex task
e.g indoor rock climbing -> free climbing
progressing the skill
Lateral/Horizontal transfer
Applying a skill to a different context
e.g climbing a ladder –> climbing a tree, badminton -> tennis
Types of Learning
Discovery learning
Explicit instructions
Analogy learning
Learning by task constraints
Observation and imitation
