Measurements

Question 1

how are robotics used

Answer 1

(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

Question 2

what are the pros and cons of robotics (kinarm)

Answer 2

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)

Question 3

what is microneurography

Answer 3

invasive technique used to record the activity of peripheral neurons
- tungsten electrode is inserted beside one nerve fibre
- guided by sound and signal properties

Question 4

what type of AP signal is most common in microneurography

Answer 4

double hat AP
- electrode hits the myelin sheath
- reads the peak of AP at the nodes of ranvier on both sides of the myelin

Question 5

what are the 5 steps of a microneurography experiment

Answer 5

1. search for peripheral nerve fibre
2. map out neurons receptive field - small probe to stimulate the skin
3. characterise neuron
4. position and calibrate stimulator rig
5. record neurons reposne to sensory stimuli

Question 6

what are the pros and cons of microneurography

Answer 6

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

Question 7

what are neural recordings

Answer 7

very similar to microneurography but in the brain
- invasive technique used to record the activity of cortical neurons

Question 8

what are single unit neural recordings

Answer 8

microelectrode placed beside the axon of a cell
EPSPs and IPSPs input via synapses on the cells dendrites

Question 9

what does the rate at which the cell fires APs provide info about

Answer 9

the cells preference for certain tasks or stimuli

Question 10

what are functional multi electrode arrays

Answer 10

record the activity of several neurons simultaneously
- can be chronically implanted

Question 11

what is centre surround inhibition

Answer 11

neurons fire when a stimulus is in their receptive field but are otherwise silent

Question 12

when is the firing rate of a neuron the highest

Answer 12

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

Question 13

what is a PSTH (post stimulus time histogram)

Answer 13

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

Question 14

what are the pros and cons of neural recordings

Answer 14

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)

Question 15

what are the principles of motion capture

Answer 15

• 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

Question 16

what are the pros and cons of motion capture

Answer 16

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

Question 17

what is the main function of EMG and what are the two types

Answer 17

technique used to record the activity of skeletal muscle during motor tasks

1. surface
2. indwelling

Question 18

what is the purpose of the ground electrode

Answer 18

used to eliminate environmental noise that contaiminates the EMG signal
- subtracted out of the surface EMG signals to get a clearer signal

Question 19

what are the principles of surface EMG

Answer 19

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

Question 20

what are the different types of surface EMG sensors

Answer 20

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)

Question 21

what are the pros and cons of surface EMG

Answer 21

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)

Question 22

what is indwelling EMG

Answer 22

invasive technique used to record activity of individual motor units in skeletal muscle

Question 23

what are the two types of indwelling EMG

Answer 23

concentric needle EMG
fine wire EMG

Question 24

how does needle EMG work

Answer 24

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)

Question 25

what are the pros and cons of needle EMG

Answer 25

pros
- can record from deep muscles
- potential to record from single MUs
- can study basic mechanisms of muscle contraction

cons
- amount of mvmt is restricted
- invasive - won’t cause damage unless there is a lot of contraction while inserted

Question 26

what is fine wire EMG

Answer 26

uses a needle insterted into skeletal muscle and ground electrode
needle is retracted leaving the wires embedded in muscle
typically used to record from deep lying muscles

Question 27

what are the pros and cons of fine wire EMG

Answer 27

pros
- can record from deep muscles
- smaller recording surface emans better resolution than surface EMG
- allows recoridng from small/adjacent muscles
- doesn’t restrict motion as much as needle EMG

cons
- invasive
- not great resolution

Question 28

what is the order of resolution from good to poor for the types of EMG

Answer 28

poor - surface EMG
ok - fine wire EMG
good - needle EMG