Measurements Flashcards
(28 cards)
how are robotics used
(kinarm)
non invasive tool that can be used to monitor and perturb mvmts to examine sensory and motor function
- used for mvmts in the horizontal plane
what are the pros and cons of robotics (kinarm)
pros
- easy and non invasive
- useful to quantifying and perturbing body motion
- easy to integrate with other tools
cons
- expensive with long set up times
- doesn’t replicate how humans actually move (only horizontal plane)
what is microneurography
invasive technique used to record the activity of peripheral neurons
- tungsten electrode is inserted beside one nerve fibre
- guided by sound and signal properties
what type of AP signal is most common in microneurography
double hat AP
- electrode hits the myelin sheath
- reads the peak of AP at the nodes of ranvier on both sides of the myelin
what are the 5 steps of a microneurography experiment
- search for peripheral nerve fibre
- map out neurons receptive field - small probe to stimulate the skin
- characterise neuron
- position and calibrate stimulator rig
- record neurons reposne to sensory stimuli
what are the pros and cons of microneurography
pros
- recoridng from individual nerve fibre
- useful for understanding sensory feedback
- can be integrated with other tools
- useful for quantifying the response properties of sensory receptors and firing patterns of MNs
cons
- time consuming and highly invasive
- restricted to relatively small mvmts and simple tasks
what are neural recordings
very similar to microneurography but in the brain
- invasive technique used to record the activity of cortical neurons
what are single unit neural recordings
microelectrode placed beside the axon of a cell
EPSPs and IPSPs input via synapses on the cells dendrites
what does the rate at which the cell fires APs provide info about
the cells preference for certain tasks or stimuli
what are functional multi electrode arrays
record the activity of several neurons simultaneously
- can be chronically implanted
what is centre surround inhibition
neurons fire when a stimulus is in their receptive field but are otherwise silent
when is the firing rate of a neuron the highest
strongest when the stimulus is in line with receptive field of the visual neuron
- orientation and spatial location of stimulus that produces the strongest responses
what is a PSTH (post stimulus time histogram)
used to visualise the rate and timing of discharges in relation to some external stimulus
- formed by counting the number of APs in certain times
what are the pros and cons of neural recordings
pros
- recording from output neurosn in cerebral cortex
- useful for understanding neural processes involved in selection, planning, and control of motor actions
- can be integrated wtih other tools
cons
- time consuming and less invasive
- expensive and lose sensitivity over time (FMA)
what are the principles of motion capture
- cameras emit light in the infrared spectrum
- light is reflected by reflective markers
- cameras record at high frame rate
- force plates can be used to measure forces when interacting with the environment
what are the pros and cons of motion capture
pros
- easy to use and non invasive
- useful for describing body motion and underlying forces
- easy to integrate with other tools
cons
- difficult to tell whether deficits of impairments are caused by sensory or motion function
- difficult to manipulate and or perturb body motion
what is the main function of EMG and what are the two types
technique used to record the activity of skeletal muscle during motor tasks
- surface
- indwelling
what is the purpose of the ground electrode
used to eliminate environmental noise that contaiminates the EMG signal
- subtracted out of the surface EMG signals to get a clearer signal
what are the principles of surface EMG
non invasive technique used to record the activity of skeletal muscle from the skin
- records the potential difference or summated activity of active motor units between the recording surfaces of electrodes
what are the different types of surface EMG sensors
wired
- button (prone to picking up other muscle signals)
- fixed plate (can’t change distance between them)
wireless
- can be used in the real world
- can miss data over bluetooth (not as accurate as wired)
what are the pros and cons of surface EMG
pros
- easy to use and non invasive
cons
- restricted to superficial muscles
- signal quality related to depth of subcutaneous tissue at recording site
- suitable for large muscles (can have crosstalk between adjacent muscles if they are small)
what is indwelling EMG
invasive technique used to record activity of individual motor units in skeletal muscle
what are the two types of indwelling EMG
concentric needle EMG
fine wire EMG
how does needle EMG work
electrode inserted into the skeletal muscle with a ground electrode
not useful for mvmt (needle isn’t flexible)
records from a single motor unit (in theory - sometimes 2)
