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SPORT SCIENCE > CONTROL OF HUMAN MOVEMENT > Flashcards

CONTROL OF HUMAN MOVEMENT Flashcards

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1
Q

How many neurones are present in the brain

A

100 billion

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2
Q

How much % of total energy does the brain consume

A

20% of total energy

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3
Q

Why doesn’t the brain feel pain

A

It has no nerves

Therefore feels no pain

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4
Q

What type of relationship do curvature and velocity have

A

positive relationship

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5
Q

what is space

A

a set of points with some added structures

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6
Q

What does Fitts Law state

A

If you need accuracy you become slower

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7
Q

What are coordinates

A

A set of numbers that uniquely determine a point in space

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8
Q

Can one space have multiple coordinate systems

A

Yes

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9
Q

What can a coordinate frame also be called

A

A reference frame

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10
Q

Define egocentric

A

coordinate system attached to our body

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11
Q

Define allocentric

A

coordinate system attached to external world/ object

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12
Q

If you are trying to find kinetics is it inverse of forward dynamics

A

Inverse

you are trying to find kinetics so you go from
kinematics –> kinetics which is inverse

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13
Q

If you are trying to find kinematics it inverse of forward dynamics

A

Forward

you are trying to find kinematics so you go from
kinetics –> kinematics which is forward

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14
Q

What does kinetics refer to

A

forces & torques

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15
Q

What does kinematics refer to

A

distances & angles

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16
Q

What is newtons 2nd law

A

F=ma

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17
Q

What is feedforward control

A

You plan in advance

Pre determined actions

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18
Q

What type of loop is feedforward control

A

open loop

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19
Q

what are the pros of feedforward control/ open loop

A

Movement can be controlled without gathering/ processing any external info

good for fast movement

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20
Q

what are the cons of feedforward control/ open loop

A

Error made by controller accumulates over time
No flexibility to environmental changes
High cost of planning, no generalisation

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21
Q

what is feedback control

A

You have policies (rule/ strategy), controller is gathering/ processing sensory feedback

eg- tube tourist example: ask around then go there, then ask again

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22
Q

what type of loop is feedback control

A

closed

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23
Q

what are the pros of feedback control/ closed loop

A

Flexible- can deal with unexpected events

Robust- control error does not accumulate over time

General- control is invariant to starting or goal opposition

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24
Q

what are the cons of feedback control/ closed loop

A

Processing sensory feedbacks is time consuming- not good for fast movement

Controller can become unstable when sensory feedbacks are noisy and the feedback gain is high (how seriously one takes the answer)

Can also become unstable when feedbacks are delayed

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25
Q

What is variability

A

When the same movement is repeated, controller behaviours under uncertainties result in different movement patterns

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26
Q

What 2 problems does the brain solve

A

Localisation

Planning

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27
Q

What is localisation

A

representation of the location of the object

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28
Q

What is planning

A

plan of reaching based on the representation

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29
Q

What sensory info is needed for localisation & planning

A

Destination (target)
extrinsic info, spatial location of the target through visual info & auditory info

Where am I/ what am I doing?
intrinsic info, kinetic & kinematic info of the body
-Muscle spindle: length and velocity of each muscle
-Golgi tendon organs: force produced by each muscle
-Mechanoreceptors: force exerted/ received on skin

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30
Q

What level of cortical control do voluntary movements need

A

a higher level of cortical control

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31
Q

How do you grab the apple in a reaching movement

general plan –> motor commands

A

Multi-stage sensorimotor transformations are required

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32
Q

What is an intrinsic coordinate system

A

joint angle coordinate
Muscle lengths
Proprioreceptive info

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33
Q

What is an extrinsic coordinate system

A

Allocentric/ egocentric coordinates

Exteroceptive (sensory info); visual & auditory

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34
Q

What is the PRR

A

Parietal reach region

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35
Q

What is the PPC

A

Posterior Parietal cortex

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36
Q

What are the sources of variability

A
  1. input- estimation of location & target
  2. intrinsic- Sensors and motor neurons, fluctuations in membrane potentials , this limits the accuracy and precision of the control
  3. output- caused by motor neurons and muscles (increased excitability + more motor neurons) this is called signal dependent noise
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37
Q

What are the internal models split into

A

Inverse- used to plan movement for a given task goal

Forward- predict consequence of the movement without sensory feedback

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38
Q

What does the inverse model do

A

determines the motor commands that will produce a behavioural goal

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39
Q

what does the forward model do

A

stimulates the interaction of the motor system and the world
can therefore predict behaviours

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40
Q

What is the efference copy

A

Within the forward model a copy of motor commands is sent to the muscles
this is the efferenence copy

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41
Q

What is directional tuning

A

Neurons in the primary motor cortex have their own preferred directions

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42
Q

What is a saccade

A

A very quick movement

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43
Q

What section of the body are feedforward controls usually used for

A

eye movement

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44
Q

What is intermittency

A

pause until sensory feedback arrives and then resumes

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45
Q

What can prediction do?

A

Compensate for sensorimotor delays

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46
Q

What is the observer model

A

How to mix what we predicted and what was sensed

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47
Q

What is the forward dynamic model

A

What is my current status (position, velocity, joint angle etc)

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48
Q

What is the forward sensory model

A

in that status what sensory info am I supposed to sense

tactile, gravity etc

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49
Q

What are the 2 types of memory

A

explicit (declarative) and Implicit (procedural)

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50
Q

What is explicit (declarative) memory

A

eg- name/ address
able to explain what you’ve learnt
easily forgotten

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51
Q

what is Implicit (procedural) memory

A

eg- learning to ride a bike/ play piano

  • takes place without consciously thinking about it
  • unable to explain what you’ve learnt
  • can be retained for extended periods of time without practice
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52
Q

What type of memories are motor skills

A

implicit

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53
Q

How are internal models maintained

A

generalisation

retrieval

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54
Q

what is generalisation

A

when a skill is learned the brain needs to utilise it in a different scenario

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55
Q

what is retrieval

A

among the skills already learned the brain needs to select the appropriate skill to use depending on the scenario

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56
Q

what cues work well for retrieving internal models

A

state-related cues

  1. visual feedbacks of movement
  2. proprioreceptive feedbacks (hand position etc)
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57
Q

what cues DONT work well for retrieving internal models

A

State-unrelated cues

  1. static cues (background colours etc)
  2. visual motions not related to the movement
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58
Q

When getting sensory feedback what is the most important thing

A

PROPRIORECEPTION! More so than vision

patients who have lost proprioreception have particular difficulty controlling the dynamic properties of their limbs

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59
Q

What does the stretch reflex do

A

keep the muscle at desired length

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60
Q

What do alpha motor neurone do

A

cause contraction of muscle

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61
Q

what do gamma moto neurons do

A

adjust the sensitivity of the reflex and allow muscles to contact until they reach desired lengths

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62
Q

What was sherringtons reflex hypothesis

A

movement is generated by stretch reflexes - which is a sensory afferent

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63
Q

What was merlons servo reflex hypothesis

A

gamma motor neuron drive precedes the movement (alpha motor neurone drive)

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64
Q

how can muscle spindle discharges be recorded

A

microneurography

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65
Q

what does EPH stand for

A

Equilibrium point hypothesis

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66
Q

What is EPH

A

EPH assumes the brain controls a virtual equilibrium point to control the reaching movement

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67
Q

what is coriolos force

A

rotation force- think spinning room get pinned against wall trying to move arms

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68
Q

what is the optical control model of movement

A

assumes that the controller tries to minimise or maximise a certain benefit produced by resultant action

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69
Q

what is jerk

A

the rate of change of acceleration

related to smoothness of the movement

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70
Q

what are properties the brain optimises

A

smoothness
torque
uncertainty
signal dependant noise

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71
Q

what is the function of dendrites

A

receives information

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72
Q

what is the function of the cell body

A

processes and integrates the information received in the dendrite

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73
Q

what is the function of the axon

A

carries the information along long distances from one part of the neuron to the other

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74
Q

what is the function of the axon terminal

A

Transmits the information to next cell in the chain

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75
Q

what is a bundle of axons together called

A

a nerve

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76
Q

what is the value for resting membrane potential

A

-70mV

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77
Q

What is threshold for membrane potential

A

-55mV or higher

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78
Q

what happens when threshold is reached

A

an action potential is triggered

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79
Q

what is depolarisation

A

ions go into the cell membrane making it become more positive

makes action potential more likely

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80
Q

what is repolarization

A

due to the electrochemical gradient, ions flow back through the cell causing it to become more negative

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81
Q

what is hyper polarisation

A

if membrane potential becomes lower than -70mV

makes action potential less likely

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82
Q

what are the passive electrical properties of neurone

A

wires conduct current by electron flow in metal

neurons conduct current by ion flow in fluid

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83
Q

what is RL

A

longitudinal resistance

want this low

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84
Q

What is RM

A

medial resistance

want this high

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85
Q

what is space constant

A

how FAR voltage travels

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86
Q

what is time constant

A

how FAST voltage travels

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87
Q

what are the 2 factors decay is defined by

A

space constant

time constant

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88
Q

anything that increases medial resistance does what to space constant

A

increases space constant

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89
Q

anything that reduces longitudinal resistance does what to space constant

A

increases space constant

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90
Q

anything that increases space constant does what to conduction velocity

A

increase conduction velocity

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91
Q

anything that reduces time constant does what to conduction velocity

A

increase conduction velocity

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92
Q

what does RMP stand for

A

resting membrane potential

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93
Q

describe how an action potential is initiated

A
  1. Cell membrane becomes depolarized
  2. Once depolarization reaches threshold, Na+ channels open
  3. Resulting in an influx of Na+ leads to further depolarization
  4. Adjacent Na+ channels are opened, causing a chain reaction
  5. Meanwhile, K+ channels open more slowly causing an outflow of K+
  6. Resulting in outflow of K+, repolarizes membrane potential
  7. Na+ channels become closed, and temporarily deactivated
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94
Q

what are the 3 states of and Na channel

A

open/ closed/ deactivated

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95
Q

what are the 2 states of a K channel

A

open/closed

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96
Q

how fast do Na and K channels open and why

A

Na channels open quickly
K channels open more slowly

This is crucial for ensuring action potential only travels in one direction

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97
Q

What increases conduction velocity

A

increased neuron diameter
myelination
temperature

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98
Q

how does increases neurone diameter increase conduction velocity

A

diameter affects RL more than RM
therefore larger space constant
therefore faster conduction

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99
Q

why does myelination increase conduction velocity

A

myelin insulation increases space constant
space constant increases conduction velocity

action potential jumps at nodes of ranvier in salutary conduction

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100
Q

give 2 examples of diseases that are effects of demyelination

A

MS

Guillian-Barre syndrome

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101
Q

how to measure conduction velocity

A

stimulate motor neuron at 2 sites
measure latency of evoked responses
calculate velocity by speed = distance/ time

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102
Q

what is a reflex

A

An action that is performed without conscious thought as a response to a stimulus

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103
Q

what do all reflexes require

A

sensorimotor integration

  1. Sensory receptor
  2. Afferent pathway
  3. Synapse onto alpha motor neuron
  4. Neuromuscular junction
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104
Q

what does it mean that the stretch reflex is autogenic

A

Autogenic means same muscle that detects the stretch is the same muscle that will contract

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105
Q

what’s afferent

A

towards CNS

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106
Q

what’s efferent

A

away from CNS

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107
Q

how does a stretch reflex cause contraction

A
  • stretch of muscle spindles
  • afferent info from muscle spindle to spinal cord
  • sensory neuron syntheses with motor neuron in cord
  • efferent info from motor neuron to muscle
  • muscle contracts
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108
Q

what does EMG stand for

A

electromyography

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109
Q

what does EMG measure

A

measures muscles response or electrical activity in response to a nerves simulation of the muscle

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110
Q

what is the purpose of stretch reflex

A

acts as a negative feedback control system to maintain desired limb position

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111
Q

why does loss of supra spinal input cause hyper reflexia/ spasticity

A

 Descending input from the brain, normally acts to regulate (inhibit) reflex gain in the spinal cord
 Spinal cord injury, stroke, and other conditions that effect upper motor neurons can abolish this tonic inhibitory input
 This causes reflex gain to increase – ‘hyper-reflexia’
 Can result in severely increased muscle tone and spasticity

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112
Q

what type of reflex is a stretch reflex

A

monosynaptic & dysnaptic

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113
Q

flexion withdrawal reflex is what type of reflex

A

polysnaptic

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114
Q

describe how Hand is moved away from painful stimulus

A
  • painful stimulus
  • pain receptors in free nerve endings stimulated
  • afferent info to spinal cord via type 3 sensory neurons
  • sensory neurons synapse with spinal cord interneurons
  • interneurons synapse with spinal cord motor neurons
  • flexor muscles in affected limb contract
  • injured area removed from stimulus
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115
Q

what is crossed extension reflex

A

contralateral limb to stimulus

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116
Q

what type of reflex is crossed extension reflex

A

polysnaptic

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117
Q

too little movement in a reflex could be caused by

A

sensory nerve damage

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118
Q

to much movement in a reflex could be caused by

A

cereal palsy
stroke
brain injury
upper spinal cord injury

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119
Q

what is a motor unit

A

one alpha neuron and all of the muscle fibres it activated

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120
Q

describe the chain of events in a muscle contraction

A
  1. Action potential (AP) stimulates the release of a neurotransmitter across the neuromuscular junction
  2. AP spreads across the sarcolemma/ muscle membrane and into fiber along the T tubules (extensions of the membrane)
  3. Causes the release of calcium from the sarcoplasmic reticulum
  4. Calcium binds to muscle and causes cross bridge cycling
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121
Q

what does one action potential create

A

a single twitch

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122
Q

what do multiple action potentials create

A

generates continuous force

tetanic contraction

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123
Q

how do muscles generate extra force

A

increasing frequency of firing of motor units

recruiting more motor units

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124
Q

what is an innervation number

A

number of fibres per motor neuron

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125
Q

what does an innervation number mean

A

lower innervation number = more control

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126
Q

what does NMJ stand for

A

neuromuscular junction

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127
Q

How do u perform EMG

A

electrical signal can be recorded by inserting a needle electrode into the muscle
OR a surface electrode at skin level

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128
Q

What is a neuromuscular junction

A

a chemical synapse between a motor unit and a muscle

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129
Q

what is the relationship between muscle force and the EMG signal

A

the amplitude of EMG signal is proportional to force produced by muscle

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130
Q

how do we see the action potential on the EMG

A

action potentials from numerous motor units summate to produce EMG signal

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131
Q

factors that affects the relationship between force and muscle activity

A

type of muscle contraction
type of muscle fibres
joint angle

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132
Q

how does type of muscle contraction affect the relationship between force and muscle activity

A

concentric v eccentric

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133
Q

how does type of muscle fibres affect the relationship between force and muscle activity

A
  • Slow v fast

- Fast = higher resting membrane potential (RMP), greater density sodium channels, faster action potentials

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134
Q

how does joint angle affect the relationship between force and muscle activity

A
  • Maximum force at particular length

- When optimal cross bridge overlap

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135
Q

what does muscle fatigue due to the with duration

A

causes prolonged twitch duration meaning an increased relaxation time due to biochemical changes in muscle

frequency of motor units firing decreases therefore less force

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136
Q

how does the nervous system know when to reduce firing rate

A 
Peripheral detection (build up of metabolites like lactate)
spinal suppression of motor neuron firing rates
changes in voluntary activation
137
Q

why does the nervous system reduce firing rate

A

reduce the likelihood of neuronal fatigue

more likely to maintain fine motor control

138
Q

what is low frequency fatigue

A

caused by intense exercise
wobbly legs following day
takes hours/ days to recover
doesn’t change EMG signal

139
Q

what is high frequency fatigue

A

caused by continuous high frequency stimulation
recovers immediately when stimulation stopped
caused by failure of transmission of action potential along muscle membrane
reduces EMG signal

140
Q

what is the function of the basal ganglia

A

Initiating movements

141
Q

what is the function of the cerebellum

A

Sensory motor coordination of ongoing movement

142
Q

what is the function of the motor cortex

A

planning, initiating and directing voluntary movements

143
Q

what is the function of the brainstem centres

A

basic movements and postural control

144
Q

what is the hierarchy of motor control in the brain

A
  1. Spinal cord
    - Motor neurons are final motor output of nervous system
  2. Muscles
    - Combined action of motor units produces smooth tetanic muscle contraction
  3. Peripheral sensation
    - Feedback from proprioception etc used to guide ongoing movement, both in spinal and supraspinal loops
145
Q

what does grey matter contain

A

cell bodies of neurons

sensory, motor & interneurons

146
Q

what does white matter contain

A

axonal tracts

147
Q

what are the parts of the spinal cord top to bottom

A

cervical
thoracic
lumbar
sacral

148
Q

what root does sensory info enter via in spine

A

dorsal root

149
Q

what root do motor neurons exit via in spine

A

ventral root

150
Q

what are the 4 main tracts of spine

A

corticospinal
rubrospinal
vestibulospinal
reticulospinal

151
Q

what are the 2 lateral tracts of the spine

A

corticospinal

rubrospinal

152
Q

what are the 2 medial tracts of the spine

A

vestibulospinal
reticulospinal

minimal concious control

153
Q

where is corticospinal tracts and what is its function

A 
From motor cortex to spinal cord. 
Major pathway for voluntary movements
precise control of limbs
especially individual finger movements
90% crosses over (contralateral)
154
Q

where is rubrospinal tracts and what is its function

A

from red nucleus (in midbrain) to spinal cord. Upper limb control (small pathway in humans)
cross over straight after exiting red nucleus
compensate for damage to corticospinal tract

155
Q

where is vestibulospinal tracts and what is its function

A

from vestibular nuclei (in medulla) to spinal cord. Automatic balance reflexes

sensory system
spatial orientation for coordinating movement with balance
output mainly to eyes

156
Q

where is reticulospinal tracts and what is its function

A

from reticular formation (in the brainstem) to spinal cord.

Postural control and balance

157
Q

how to measure integrity of corticospinal tract

A 
TMS of motor cortex
Babinski reflex (extension of big toe)
158
Q

where do the motor neurons lie that allow flexion

A

more centrally

159
Q

where do the motor neurons lie that allow extension

A

on outside

160
Q

what does gray matter look like

A

H shape

161
Q

white matter ascending tracts contain what

A

sensory neurons

162
Q

white matter descending tracts contain what

A

axons of upper motor neurones

163
Q

what is the primary motor cortex also known as

A

M1 or Brodmanns area

164
Q

what is a motor homunculus

A

Shows what a persons body would look like if it grew in proportion to the area of the cortex concerned with its movement

165
Q

what is the function of the primary motor cortex

A

generates the nerve impulses initiating movements

166
Q

where is brocas area located

A

a circular dot in the premotor cortex

167
Q

what is the function of brocas area

A

involved in language expression

168
Q

What does kinematics relate to

A

direction
amplitude
speed
path

169
Q

what does kinetics relate to

A

force & muscle activity

170
Q

how do you extract movement info directly from cortical neurons in reaching movements

A

put a micro electrode array into motor cortex

single unit recordings made during reaching movements in multiple directions

171
Q

What is TMS

A

Non invasive brain stimulation technique
Uses electromagnetic induction to activate neurons
Stimulates M1 and records MEPs using EMG
Also records excitability of CS tract

172
Q

How does TMS stimulate cortical interneurons

A

Stimulate at sub threshold intensities
This targets inhibitory interneurons
Gets a decrease in CS tract activity leading to decreased MEP and decreased voluntary EMG

173
Q

Does MEP latency vary between people

A

yes

174
Q

does m1 excitability increase immediately before movement

A

yes

175
Q

what happens to MEPs if you have an injury along the corticomotor pathway

A

you may show abnormal MEPS

176
Q

what does a decrease in MEP from the same TMS intensity show

A

decreased corticomotor excitability

177
Q

What is the function of the basal ganglia

A

control the strategic aspects of movement

178
Q

does the basal ganglia connect to the spinal cord

A

no direct connection

179
Q

what does damage to the basal ganglia result in

A

problems initiating/ terminating movements

180
Q

what are the 5 nuclei in the basal ganglia

A 
caudate
putamen
globus pallidas
subthalamatic nucleus
substantia nigra
181
Q

how do you identify the caudate

A

looks like a C (and called caudate)

182
Q

which basal ganglia nuclei form the striatum

A

caudate

putamen

183
Q

What are the 2 parts to the globus pallidus nuclei

A

internal

external

184
Q

What are the input nuclei in basal ganglia

A

STRIATUM (caudate & putamen)

Receives connections from cortex

185
Q

What are the output nuclei in basal ganglia

A

globus pallidus internal (GPi)
Substantia nigra

provide tonic inhibitory output to thalamus
no output directly to spinal cord

186
Q

what does the direct pathway motor loop of basal ganglia do to movement

A

facilitates movement

187
Q

what does the indirect pathway motor loop of basal ganglia do to movement

A

inhibits movement

188
Q

what is the route of the direct pathway motor loop of basal ganglia

A 
motor cortex
striatum
GPi
thalamus
back to motor cortex
189
Q

what is the route of the indirect pathway motor loop of basal ganglia

A 
motor cortex
striatum
GPe
STN
Gpi
Thalamus
back to motor cortex
190
Q

what does the direct pathway motor loop of basal ganglia do to drive

A

increases drive/ movement initiation

191
Q

what does the indirect pathway motor loop of basal ganglia do to drive

A

decreases drive

movement termination

192
Q

What is Parkinson’s disease

A

degeneration of dopamine neurons
more indirect pathway,
less direct pathway
therefore movement suppressed

193
Q

what is Huntington’s disease

A

Movement facilitated-
rapid jerky motions
Caused by mutation of Huntingtin gene

Down regulation of indirect pathway, more direct pathway therefore movement facilitated

194
Q

what is hyperkinetic

A

increased/ too much movement

195
Q

What is hypokinetic

A

reduced movement

196
Q

medical treatment of basal ganglia pathology is aimed at what

A

restoring balance between indirect and direct pathway

197
Q

what is the function of cerebellum

A

modulates movement accuracy

receives afferent info from spinal cord

198
Q

what does damage to cerebellum cause

A

inaccurate/ poorly timed movement

199
Q

what are the 3 anatomical parts of the cerebellum

A

anterior lobe
posterior lobe
flocculonodular lobe

200
Q

what are the 5 cell types in the cerebellum

A 
purkinje cell
Golgi cell
granule cell
stellate cell
basket cell
201
Q

what are the 3 layers in the cerebellum

A

molecular layer
purkinje layer
granular layer

202
Q

what are the 2 inputs to the cerebellum (fibres)

A

climbing fibres

mossy fibres

203
Q

what is the output of the cerebellum

A

purkinje cells

204
Q

what are the 3 functional regions to the cerebellum

A

vestibulocerebellum
spinocerebellum
cerebrocerebellum

205
Q

describe vestibulocerebellum

A

regulates balance & eye movement
coordinates movements of head & eyes

the flocculondular lobe (bottom part)

206
Q

what are the inputs to vestibulocerebellum

A

vestibular system
visual system
somatosensory system (neck)

207
Q

what are the outputs of vestibulocerebellum

A

vestibular nuclei in the brainstem

208
Q

damage to vestibulocerebellum results in what

A

damage results in deficits in smooth eye movements and balance

209
Q

what are the inputs to spinocerebellum

A
  • Motor and sensory cortex
  • Somatosensory receptors (trunk & limbs) via spinal cord. Conveying info about touch pressure & limb position
  • Auditory and visual systems
210
Q

what are the outputs to spinocerebellum

A

Vestibular & retricular nuceli (movements of neck, proximal parts of arm), posture & balance

  • Red nucleus, direct control to distal parts of arm
  • Motor cortices (Via VL thalamus), control via corticospinal tract
211
Q

describe the spinocerebellum

A
  • Controls posture and locomotion as well as eye movements
  • Inactivation of spinocerebellum causes movements to become slower and more
  • consists of vermis and intermediate hemispheres (middle part)
212
Q

describe cerebrocerebellum

A

consists of lateral hemispheres (side parts)

  • Part of high-level internal feedback circuit that plans movement and regulates cortical motor programmes
  • Controls mental rehearsal of complex motor actions and measures movement
213
Q

what are the inputs to cerebrocerebellum

A

-Cerebral cortex (Sensorimotor & secondary visual regions)

214
Q

what are the outputs to cerebrocerebellum

A
  • Motor, pre motor, pre frontal & parietal cortices (via VL thalamus)
  • Inferior olive (via red nucleus)
215
Q

what does damage of cerebrocerebellum result in

A

-Damage results in irregularities in the timing of movement components

 Ataxic gait
 Impaired balance
 Slurred speech

216
Q

what is ataxia

A

abnormal execution of multi jointed voluntary movements, characterised by lack of coordination

ataxic gait is weird retarded walk

217
Q

what is dysmetria

A

inaccuracy in range and direction of movement

218
Q

what is dysdiadochokinesia (ddk)

A

Impaired ability to perform rapid alternating movements

219
Q

what are compressions of sound waves

A

compressions are regions of high pressure due to particles being close together

220
Q

what are rarefactions of sound waves

A

rarefactions are regions of low pressure due to particles being spread further apart.

221
Q

what is amplitude

A

a measure of loudness

222
Q

what is frequency

A

how many sound waves there are each second

223
Q

what is frequency measured in

A

Hertz

224
Q

what is the range of human hearing

A

20-20,000 Hz

225
Q

what is the range of human hearing

A

20-20,000 Hz

0-140decibels

226
Q

what happens to hearing with age

A

it deteriorates

227
Q

what are the 3 sections to the ear

A 
outer ear (air)
middle ear (air)
inner ear (fluid)
228
Q

what does the cochlea look like

A

spiral

229
Q

what’s the function of the middle ear

A

converts high amplitude at ear drum into low amplitude at oval window

230
Q

what is the function of strapedius reflex

A

protects ear against loud sound

231
Q

how does the strapedius reflex work

A

contraction of ‘tensor tympani’ and ‘stapedius’ pulls stapes away from oval window

decreases transmission of vibrational energy to cochlea

strapedius reflex occurs in response to very loud sound

232
Q

what happens to tympanic membrane & Eustachian tubes when flying at TAKE OFF

A

Pressure in middle ear is larger than ear canal

Therefore tympanic membrane moves outwards

If you swallow you open up the Eustachian tubes and equalise pressure allowing tympanic membrane to return to normal position

233
Q

what happens to tympanic membrane & Eustachian tubes when flying at LANDING

A

Pressure in middle ear is smaller than ear canal

Therefore tympanic membrane moves inwards

If you swallow you open up the Eustachian tubes and equalise pressure allowing tympanic membrane to return to normal position

234
Q

what are the 3 scale in cochlea

A

vestibuli
media
tympani

235
Q

what part of the ear is the cochlea in

A

inner ear

236
Q

where is the organ of corti found

A

embedded into basilar membrane

237
Q

how are hair cells in organ of corti activated

A

when hair cells moved in one direction = depolarisation

when hair cells moved in another direction = hyperpolarisation

238
Q

what are large hairs called

A

kinocillium

239
Q

what are small hairs called

A

stereocilia

240
Q

what happens when sound moves away from kinocillium

A

movement = inhibited

241
Q

what happens when sound moves towards kinocillium

A

movement = excited

242
Q

what is Fourier analysis of sound

A

any waveform can be decomposed into sine waves of various frequencies

decomposes time based sound signals into their frequency components

243
Q

what are otoacoustic emissions

A

echoes in response to clicks delivered to the ear

244
Q

what happens to outer hair cells in response to sound

A

they contract and relax in response to activation from sound. can be known as active undamping

245
Q

what is wernickes area of brain linked to

A

speech

246
Q

what type of frequency is human hearing most sensitive at

A

speech frequencies

247
Q

what is sound localisation split into

A

judging distance

judging direction

248
Q

what is inter aural time delay (ITD)

A

a click from the left will arrive at the left ear first, then right ear soon after

the bigger the animals head the bigger the ITD

249
Q

what size head is better for detecting HIGH frequency sounds

A

a smaller head is better for detecting high frequency sounds

250
Q

are sounds with a narrow band of frequencies hard or easy to localise

A

narrow band of frequency = hard to localise

251
Q

are there any photoreceptors in the optic nerve

A

NO

252
Q

where is the sclera

A

white jelly over eyeball

253
Q

where are zonular fibres

A

next to lens

254
Q

where are cilary muscles

A

after the zonular fibres

lens, zonular, ciliary

255
Q

how do you determine lens strength

A

difference in refractie index, combined with lens curvature

256
Q

what do relaxed ciliary muscles do to the lens

A

oval - long/ stretched

257
Q

what do contracted ciliary muscles do to the lens

A

circular/ round

258
Q

what is myopia

A

short sighted

259
Q

what is hypermetropia

A

long sighted

260
Q

how do you compensate for myopia

A

biconcave lens

261
Q

what lens compensates for hypermetropia

A

biconvex lens

262
Q

what is presbyopia

A

when the lens seizes up
the lens no longer bulges when ciliary muscles contract

happens with age - why older people need reading glasses

263
Q

what are the 2 muscles that control pupil diameter

A 
sphincter pupillae (around pupil)
dilator (on top of iris)
264
Q

why does the pupil change size

A

adapts to light levels

265
Q

what is an ophthalmoscope

A

shines light directly onto subjects retina
adjustable lens used to bring retina into focus

optician can work out what strength glasses to give based on the ophthalmoscope lens required to bring retina into focus

266
Q

what colour is the longest wavelength

A

red

267
Q

what colour is the shortest wavelength

A

purple

268
Q

what do ciliary muscles look like when they are contracted

A

thick

269
Q

what do ciliary muscles look like when they are relaxed

A

thin

270
Q

do rods, cones, horizontals and bipolars have action potentials

A

NO

271
Q

What part of eye contains highest % of photoreceptors

A

fovea

272
Q

in bright light can cone cells be used

A

YES

273
Q

in bright light can rod cells be used

A

NO

274
Q

Which one out of rods and cones is responsible for colour

A

cones

remember c for cones c for colour

275
Q

what protein in the eye needs to be constantly regenerated as it is bleached by light

A

rhodopsin

276
Q

what are the 3 stages of phototransduction

A
  1. photopigment bleaching
  2. cell membrane hyperpolarized via G protein
  3. Neural output of ganglion cell is modified
277
Q

describe stage 1 of phototransduction (photopigment bleaching)

A

 Two molecules (retinal & opsin) combine to form photopigment called rhodopsin (unbleached state)
 Light photon interacts with rhodopsin causing configurational change
 Retinal & opsin part company (bleached)

278
Q

describe stage 2 of phototransduction (cell membrane hyperpolarized via G protein)

A

 Released opsin activates enzyme phosphodiesterase (PDE) via transducing G protein
 PDE converts cGMP to GMP (cGMP normally opens Na+ channels)
 Closure of Na+ channels causes hyperpolarization of cell because K+ continues to leak out

279
Q

describe stage 3 of phototransduction (Neural output of ganglion cell is modified)

A

 Rod/ cone hyperpolarization results in LESS neurotransmitter release (glutamate)
 Modulates membrane potential of bipolar cell
 Changes firing rate of ganglion cell (bipolar can be excitatory or inhibitory)

280
Q

what is scotopic vision

A

low light vision
rods ONLY
High sensitivity

281
Q

what is photopic vision

A

high luminance
cones ONLY
Low sensitivity

282
Q

what is mesopic vision

A

medium light
rods and cones
medium sensitivity

283
Q

what is 0 visual acuity

A

a blind spot

284
Q

what is lateral inhibition of the eye

A

centre surrounded receptive field, edge detection, contrast illusions

285
Q

what are the 3 colours of cones

A

red
green
blue

286
Q

what is a monochromat

A

someone who is completely colour blind

287
Q

what is a dichromat

A

someone who can only see 2 colours

288
Q

what are the 3 main contributors to orientation

A 
vision (visual space)
vestibular system (inertial space)
proprioreception (internal space)
289
Q

what type of movement/ velocity do canals control

A

angular velocity/ rotation

290
Q

what type of movement/ velocity do otoliths (utricle & saccule) control

A

linear acceleration/ tilt

291
Q

what does movement towards stereocillium cause

A

depolarises receptor and increases firing rate of afferent

292
Q

what are otoconias in the ear

A

calcium carbonate deposits

293
Q

why do canals detect movement in any direction

A

the canals are perpendicular to each other

294
Q

what is positional alcohol nystagmus

A

caused by the cupola no longer being neutrally buoyant and therefore room feels like its spinning when you lie down after alcohol

295
Q

what is the vestibular ocular reflex (VOR)

A

stabilises gaze during head motion

rotates eyes to compensate for head movement

296
Q

what is caloric vestibular stimulation

A

method of modulating firing rate of the primary vestibular afferents of ear canal with warm or cold water

297
Q

what is GVS

A

galvanic vestibular stimulation

activates the nerves from all canals, causing a head roll sensation
causes locomotor and balance responses

298
Q

what is higher the utricle or saccule

A

utricle is on top of saccule

299
Q

define proprioreception

A

the sense of the relative position of neighbouring parts of the body

300
Q

what does gamma motor neuron do to muscle spindle

A

gamma motor neurons contract muscle spindle

301
Q

what are the 2 roles of the muscle spindle

A

detect static length of muscle (position)

detect rate of change of muscle stretch (velocity)

302
Q

what is alpha gamma coactivation

A

maintains sensitivity of spindle in the face of changing muscle length

303
Q

what do the primary endings in a muscle spindle react to

A

velocity and position

304
Q

what do the secondary endings in a muscle spindle react to

A

position ONLY

305
Q

what is GTO and what does it signal

A

Golgi tendon organ

signals force and heaviness

306
Q

what happens to ankle proprioception with age

A

ankle proprioception declines with age

307
Q

Define balance

A

maintaining centre of mass (COM) within the base of support (BOS)

308
Q

When swaying forwards what stops us from falling

A

constantly activating calf muscles

309
Q

what is motion parallax

A

objects appear to move relative to each other depending on focus point
eg- you may think your train is moving when actually the other train is moving

310
Q

describe beginning of walking stance

A

eccentric contraction of extensors provides braking action

311
Q

describe end of walking stance

A

concentric action of extensors provides push off power

312
Q

what happens when humans run around curves

A

we have to slow down due to anti gravity function

however dogs don’t have this and can therefore keep running at same speed

313
Q

when walking what % is swing and what % is stance

A

40% swing

60% stance

314
Q

what is locomotor CPG

A

A complex spinal neural network capable of producing functional locomotor muscle activation patterns without any contribution from afferent feedback

315
Q

why do we move our eyes

A

to bring points of interest over the fovea (foveating)

to prevent blurring of visual scene

316
Q

what are the 2 types of eye movement

A

fast

slow

317
Q

describe fast eye movement

A

saccades

318
Q

describe slow eye movement

A

vestibular ocular reflex
optokinetic reflex

These maintain stable image on retina
Smooth pursuit- tracks moving objects
Vergence- points eyes in same direction

319
Q

what are the 2 types of saccade

A

reflex (stimulus driven)

voluntary

320
Q

what are hypermetric saccades

A

eyes going too far and then having to readjust

321
Q

what are hypometric saccades

A

eyes severely undershoots, has to do lots of little adjustments to get eyes to look where he wants to look

322
Q

what part of brain is important for tuning saccadic eye movements

A

cerebellum

323
Q

when does the Vestibular ocular reflex (VOR) go wrong

A

vestibular loss
-viral infection, head injury (loss of balance/ disorientation

ageing
-vestibular hair cells lost with age

alcohol
-alcohol nystagmus causes changes in gravity of fluid in canals

324
Q

what is optokinetic reflex (OKR)

A

performs similar function to VOR

better for low frequency movements

325
Q

what is smooth pursuit

A

ability to track a moving object

must involve some prediction as visual feedback is too slow

326
Q

what is vergence

A

ability to direct eyes towards the same point

327
Q

what are the 4 methods of eye tracking

A

scleral coil

infrared reflectance

electrooculography (EOG)

Video-oculography

328
Q

what is scleral coil method of eye tracking

A

contact lens with embedded wire coils
very uncomfortable & invasive
can measure eye position very accurately in all 3 axes

329
Q

what is infrared reflectance method of eye tracking

A

Beam of infrared reflected from cornea onto sclera
As eye rotates the beam is reflected in a different direction
This change in position is detected by the IR detector

Can be used in dark

330
Q

what is electrooculography method of eye tracking

A

Retina produces measurable electric charge
Permenant electrical dipole between cornea and retina
As eye rotates, voltage between electrodes changes

Works with eyes closed
Can measure both horizontal & vertical movement
Cheap & easy

331
Q

what is video oculography method of eye tracking

A

use software to track pupil

332
Q

describe divergence

A

picture 2 eyeballs looking parallel

333
Q

describe convergence

A

picture 2 eyeballs with their gaze meeting in the distance

334
Q

What is the “after-effect” in force-field adaptation?

A

Error in opposite direction in early post-exposure

335
Q

what is a contextual cue

A

a piece of information that is related to a specific motor skill

336
Q

what is equifinality in EPH

A

Movement is independent of initial position, and only depends upon final position

337
Q

Why would you sometimes want to SUPPRESS reciprocal inhibition?

A

To simultaneously activate agonist and antagonist muscles surrounding a joint

338
Q

What is the evidence for prediction in smooth pursuit eye movement?

A

The eye movement continues briefly after the target disappears

SPORT SCIENCE (9 decks)

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