ch 1: sensorimotor cntrl intro Flashcards
motor behaviour
includes individual movements and motor skills
motor skill
goal-directed task, voluntary head/limb/body movements, made up of a series of movements
movement
make up components of a motor skill
how are movements different than skills?
skills= related to the outcome
movement= relate to specific characteristics
motor behaviour is a combination of ____ and ____ control
feedforward, feedback
feedforward control
Uses sensory information prior to the execution of movement rather than during the
movement, rapid, planned
ex. swatting a mosquito
feedback control
uses sensory feedback during movement
ex. catching a ball
4 sensorimotor problems associated with control of movement
- degrees of freedom
- serial-order problem
- sensorimotor integration problem
- motor learning problem
What problems do DOF solve?
avoid injury by limiting extreme joint angles
serial order problem
movements must be sequences by nervous system. must form a “motor plan”. can use co-articulation (simultaneous motion of different effectors/limbs over a period of time)
sensorimotor integration problem
sensory info is captured by many different types of receptors- which to use? which spatial coordinates? (body-centered, world-centered, etc.)
Motor learning problem
which motor skills are we born with and which need to be learned?
postural stability (balance)
ability to keep the body’s COM within BOS
standing balance has a small amount of
postural sway
factors affecting postural sway
1) Physical characteristics of the individual (age, fatigue)
2) Stance Posture (BOS)
3) Support surface characteristics (compliant terrain incr. sway)
4) Availability of sensory information/systems
5) Psychological Factors (fear, multitasking)
3 sensory systems
visual, vestibular, somatosensory
anticipatory postural adjustments (APAs)
postural mechanisms that occur prior to or during postural disturbance due to self movement
purpose of APAs?
- to maintain postural stability (equilibrium)
- to stabilize the position of relevant body segments
reaching/grasping- what needs to be known?
-location of target
-characteristics of target
-initial shoulder/arm configuration
3 components of reaching
-transport hand to object
-align hand w object
-pre-shaping of fingers to grab object
Saccades
Rapid voluntary movements of the eyes. too fast for sensory feedback
smooth pursuit
a type of voluntary eye movement in which the eyes move smoothly to follow a moving object
why are they called “APAs’ if they sometimes happen at the same time as the primary movement?
delays in both sensory processing and motor action. Even if APA happens at same time as primary movement, it is still anticipatory because the brain had to plan that adjustment before the movement occured
What are the first muscles to activate during and arm raise while standing?
posterior leg muscles (gastrocnemius and hamstring) activate first to counteract the COM disturbance caused by raising your arm
Why do you first need to shift your weight to the leg that will be raised?
need to shift weight to the “support” side but to do that you need to push your COM towards the support side using the leg that will eventually be raised
where is the COM? how is it changed?
-the point that is the centre of the total body mass
-roughly at belly button
-nervous system attempts to control the position of this through activation of different muscles
BOS
-base of support
-area of the body that is in contact with the support surface + space on the ground between these contact points
COP
centre of distribution of total force applied to supporting surface
where is COP when standing on one foot?
edge of supporting foot
where is COP when standing on two feet?
somewhere in between both feet (depending on which side you are leaning on more)
If you move, you are disturbing your —
COM. which you must control. APAs minimize potential disturbance that the movement may cause
WALKING:
goal-directed walking relies on —-
multiple sensory systems, relies heavily on spinal cord integration
Phases of walking
- stance phase
- swing phase
think of walking as —
a series of controlled falls
gaze shifts involve coordination between
the eyes and the head
neuromechanical limit
the largest eye movements are no greater than about 40-45 degrees in either direction from the central orbital position
how can we extend the neuromechanical limit?
head movements accompany eye movements.
how do eyes and head work together?
eyes move first, then head moves while gaze remains on target
3 factors of motor behaviour (the framework diagram)
- the environment
- the individual
- the task
Individual- subcategories
- cognitive: attention, motivation, emotional
- sensory: sensory info
- motor: accuracy of movement, coordinates muscles and joints
Task- subcategories
- object interaction (carrying, hitting it, manipulating it?)
- stability constraints (relates to BOS) as each requires different level of control
–> stationary BOS=sitting ,standing
–> moving BOS=walking
Environment: what are the relevant environmental features that affect motor behaviour?
- size, shape and speed of objects
- terrain
- weather
- ambient lighting
3 categories of motor behaviour
- reflexive: involuntary patterns of muscle contraction and relaxation
- rhythmic: repetitive (chewing, swallowing, scratching, walking)
- voluntary: goal-directed
3 one-dimensional classification systems for motor behaviour
- size of primary musculature required (gross vs. fine)
- specificity (continuous vs. discrete)
- stability of environment (open; changing envt vs. closed; stable envt)
discrete, continuous or serial?
kicking a ball
discrete
discrete, continuous or serial?
swimming
continuous
discrete, continuous or serial?
gymnastics routine
serial
continuous movements can be divided into types of tracking tasks:
- pursuit tracking
- compensatory tracking
- step tracking
pursuit tracking
eyes track a moving object
compensatory tracking
maintain target value at a set location
–> example: turbulence may affect aircraft instruments, pilot returns it to “normal”
step tracking
ex. an object suddenly shifts to a new location and you must quickly shift gaze to follow
