Anat

Front 1

what do lower motor neurons talk to?

Back 1

muscle fibres

Front 2

what are lower motor neurons innervated by?

Back 2

ventral horn of spinal cord

Front 3

where are most lower motor neurons located?

Back 3

lumbar and cervical

Front 4

what are the 2 types of lower motor neuron?

Back 4

alpha and gamma

Front 5

what is the motor system?

Back 5

muscles and neurons that control muscles

Front 6

what are the 2 parts of motor control and what do they do?

Back 6

1. spinal cord - coordinated muscle contraction
2. brain - motor programs in spinal cord

Front 7

what makes up the bulk of body muscle mass?

Back 7

skeletal muscle

Front 8

what structures does smooth muscle line?

Back 8

arteries, digestive tract, related structures

Front 9

what 3 muscles make up the somatic musculature?

Back 9

1. axial muscles - trunk movement
2. proximal muscles - shoulder, elbow, pelvis, knee movement
3. distal muscles - hands, feet, digits (fingers and toes) movement

Front 10

what does upper motor neuron do?

Back 10

supplies input to the spinal cord

Front 11

where are upper motor neurons located?

Back 11

brain

Front 12

where do upper motor neurons send signals?

Back 12

the spinal cord which contains the lower motor neurons

Front 13

from where do alpha motor neurons receive signals?

Back 13

-spinal interneurons
-senory input from muscle spindles
-upper motor neurons in brain

Front 14

what is the sensorimotor system?

Back 14

sensory information used by the motor system

Front 15

what is the hierarchy of (brain influenced, spinal cord movement) voluntary movement?

Back 15

highest level: strategy
middle level: tactics
lowest level: execution

Front 16

what are the two major pathways axon from the brain descend?

Back 16

-lateral pathways
-ventromedial pathways

Front 17

what are the 3 lateral pathways? are they voluntary or involuntary?

Back 17

corticospinal tract, rubrospinal tract and pyramidal tract. voluntary

Front 18

what are the 4 ventromedial pathways?

Back 18

tectospinal tract, vesibulospinal tract, pontine reticulospinal tract, medullary reticulospinal tract

Front 19

what are voluntary movements under control of?

Back 19

direct cortical control

Front 20

what is the effect of lesions on the corticospinal and rubrospinal tracts?

Back 20

fractioned movement of arms and hands

Front 21

what is the effect of damage to the corticospinal tract?

Back 21

paralysis on contralateral side

Front 22

what are the ventromedial pathways under control of?

Back 22

posture and locomotion - under brain stem control

Front 23

what does the motor cortex consist of?

Back 23

area 4 = primary motor cortex/M1 and area 6 = higher motor area consisting of the lateral region (premotor area (PMA)) and the medial region (supplementary motor area (SMA))

Front 24

which direction do lateral pathways travel?

Back 24

brain to spine

Front 25

how is movement initiated by the primary motor cortex? (3 ways)

Back 25

- electrical stimulation of area 4
- the input/output organisation of M1(2 sources of input to Betz cells (pyramidial cells in cortical layer 5) from the cortical areas and the thalamus)
-the coding of movement in M1 (activity from several neurons in M1encodes force and direction of movement)

Front 26

how many cortical layers/laminae are there?

Back 26

6

Front 27

the cortical layers are numbered 1-6 in which direction?

Back 27

outside (just deep to pial surface) to inside (layer 6 touches the underlying white matter)

Front 28

which cortical layer has the largest neurons?

Back 28

5 (Betz cells (neurons of pyramidal cells) - motor cortex)

Front 29

how many neurons does layer 1 have?

Back 29

few

Front 30

what size neurons do layers 2 and 3 have?

Back 30

medium sized. layers 2 and 3 are difficult to distinguish from each other

Front 31

what size neurons does layer 4 have?

Back 31

very small

Front 32

what size neurons does layer 5 have?

Back 32

very large

Front 33

what size neurons does layer 6 have?

Back 33

medium sized

Front 34

what is the corticospinal tract?

Back 34

travels cortex to peduncles to midline to pyramidal tract to corticospinal tract to spinal cord. if damaged, paralysis on contralateral (opposite) side

Front 35

what is the rubrospinal tract?

Back 35

o rubrospinal (red nucleus, if damaged lose drive to extensors) always considered with cerebrospinal tract – innervates lower motor neurons in same way. Only innervates upper limbs (mostly found in cats, humans, monkeys). Extensor muscles.

Front 36

what happens if lesions are formed on any of the corticospinal, rubrospinal or pyramidal tracts?

Back 36

fractioned movements of the arms and hands

Front 37

what happens is only lower motor neurons are damaged?

Back 37

flaccid paralysis (muscles lose neural drive and become floppy)

Front 38

what happens if only upper motor neurons are damaged?

Back 38

spastic paralysis (too many neurons fire = rigid)

Front 39

what is the vestibulospinal tract?

Back 39

balance - postural muscles get wrong signal is damaged

Front 40

what is the tectospinal tract?

Back 40

(tectum = dorsal part of midbrain(visual/auditory input-makes orienting movements – to and avoid)) - neck and eye muscles

Front 41

what do the pontine and medullary reticulo(big dendrites)spinal tracts control?

Back 41

sexual, excretion, blood vessels, heart (primitive)

Front 42

how is direction of movement in M1(primary motor cortex) decided?

Back 42

each cell represents a single 'vote' - direction of movement determined by a tally and averaging

Front 43

what does decoding M1 pathway acheive?

Back 43

helps patients with severe damage to their motor pathways

Front 44

in experiments on rats, microstimulation of M1 cortex normally elicits whisker movement, what happens if the nerve that supplies whisker movements is cut?

Back 44

microstimulation now causes forelimb movement

Front 45

how do the posterior parietal and prefrontal cortex contribute to motor control?

Back 45

they represent the highest level of motor control: decisions made about actions and their outcome.

Front 46

in the planning of movement by the cerebral cortex, where does area 5 (posterior parietal cortex) receive input from?

Back 46

areas 3, 1 and 2 (SI)

Front 47

in the planning of movement by the cerebral cortex, where does area 7 (posterior parietal cortex) receive input from?

Back 47

inputs from higher order visual cortical areas such as MT

Front 48

how do the anterior frontal lobes contribute to the planning of movement by the cerebral cortex?

Back 48

they control abstract thought,decision making and anticipating consequences of action

Front 49

how does area 6 contribute to motor control?

Back 49

actions converted into signals specifying how actions will be performed

Front 50

what is per roland?

Back 50

monitored cortical activation accompanying voluntary movement (PET). results supported view of higher order motor planning

Front 51

what are evarts?

Back 51

recorded activity in motor areas of awake, behaving animals.

Front 52

what have evarts demonstrated?

Back 52

the importance of area 6 in planning movement
-'ready' - parietal and frontal lobes
-'set' - supplementary and pre-motor areas
-'go' -areas 6/4

Front 53

where does the basal ganglia project?
where does it provide major input?

Back 53

ventral lateral (VLo) nucleus. basal ganglia provides major input to area 6

Front 54

what projects to the basal ganglia?

Back 54

the cortex (forms a loop)

Front 55

what is connected to the basal ganglia?

Back 55

substantia nigra

Front 56

what is the basal ganglia made of?

Back 56

caudate nucleus, putamen, globus pallidus, subthalamic nucleus

Front 57

what are the caudate nucleus and putamen collectively known as?

Back 57

striatum

Front 58

what is the direct path of the basal ganglia motor loop?

Back 58

excitatory connection from the cortex to cells in the putamen

Front 59

what does the basal ganglia motor loop control?

Back 59

selection and initiation of willed movements

Front 60

what does cortical activation (motor loop) cause? (3 things)

Back 60

-excites putamen neurons
-inhibits globus pallidus neurons
-release cells in VLo from inhibition (activity of VLo influences activity in SMA)

Front 61

what are some basal ganglia disorders?

Back 61

hypokinesia and hyperkinesia.
parkinsons, huntingtons, hemiballismus

Front 62

what are the symptoms, organic basis and DOPA-treatment for parkinson's disease?

Back 62

symptoms:
bradykinesia, akinesia, rigidity and tremors of hand and jaw
organic basis:
degeneration of substantia nigre inputs to striatum
DOPA-treatment:
facilitates production of dopamine to increase SMA activity

Front 63

what are the symptoms of huntington's disease?

Back 63

hyperkinesia, dyskinesia, dementia, impaired cognitive disability, personality disorder

Front 64

what are the symptoms of hemiballismus?

Back 64

violent, flinging movement on one side of body

Front 65

what is ataxia?

Back 65

uncoordinated and inaccurate movements caused by cerebellar lesions. the symptoms of which include dysnergia and dysmetric

Front 66

what does the deep cerebellar nuclei (cerebellum) do?

Back 66

relays cerebellar cortical output to brain stem structures

Front 67

what does the vermis (cerebellum) do?

Back 67

contributes to ventromedial pathway

Front 68

what do the cerebellar hemispheres (cerebellum) do?

Back 68

contribute to lateral pathways

Front 69

what does the motor loop through the lateral cerebellum pass through?

Back 69

-pontine nuclei (axons from layer 5 pyramidal cells in the sesorimotor cortex form massive projections to pons)
-corticopontocerebellar projection (20 times larger than pyramidal tract)

Front 70

what is the function of the lateral cerebellum motor loop?

Back 70

execution of planned, voluntary, multijoint movements

Front 71

in eg. baseball pitcher:
walking uses which pathway?

Back 71

ventromedial pathways

Front 72

eg bp:
ready to pitch?

Back 72

neocortex, ventromedial pathways

Front 73

eg bp:
pitch signs and strategy

Back 73

sensory information engages parietal and prefrontal cortex and area 6

Front 74

eg bp:
winds and throws

Back 74

-increased basal ganglia activity (initiation)
-SMA activity leads to M1 activation
-corticopontocerebellar pathways to cerebellum
-cortical input to reticular formation leads to release of antigravity muscles
-lateral pathway engages motor neurons leads to action.

Front 75

in development, what is the mechanism of axonal target-finding?

Back 75

-growth cones
-influence by matrix and growth factors
-temporary connections: immature and without target cells, decoy cells required, decoy cells die.

Front 76

what is the sensory pathway?

Back 76

sensory receptor to spinal cord or brain stem nuclei to thalamus to primary cortical area

Front 77

give the sensory pathway travelled for eg auditory receptor in cochlea

Back 77

auditory receptor in cochlea to brain stem nuclei to medial geniculate (part of the auditory thalamus) to auditory cortex

Front 78

give the sensory pathway travelled for photoreceptors in retina

Back 78

photoreceptors in retina to other retinal neurons to lateral geniculate to visual cortex

Front 79

what is sensory transduction?

Back 79

when environmental stimulus causes electrical response in receptor cell (somatosensory receptors)

Front 80

where are there somatosensory receptors in skin?

Back 80

merkel's disk, meissner's corpuscle, pacinian corpuscle, ruffini's ending, free nerve endings, hair follicle receptor

Front 81

where are there somatosensory receptors in muscle and joints?

Back 81

neuromuscular spindle (jerk reflex), golgi tendon organ (muscle tension)

Front 82

where are there somatosensory receptors in vision?

Back 82

all within CNS

Front 83

how does sensory reception work?

Back 83

-all sensory fibres carried by spinal nerves have cell bodies in dorsal root ganglia and a central process which enters the spinal cord via the dorsal root.
-second order fibres synapse in the thalamus on the contralateral side before projecting to the somatosensory cortex
-S1 cortex is mapped according to body plan; more sensitive regions occupy more cortex

Front 84

what are the exeptions to the general pathway of somatosensory reception?

Back 84

olfaction - smell doesn't synapse in the thalamus, goes directly to olfactory complex.
auditory/vestibular - terminates (synapses) in brainstem

Front 85

where are taste receptor cells?

Back 85

papillae (not neurons but synpase with afferent axons)

Front 86

what are the 5 tastes?

Back 86

salty, sweer, sour, bitter, umani

Front 87

how does 'salty' taste work?

Back 87

Na+ passes through channel

Front 88

how does 'sour' taste work?

Back 88

acidic H+ passes through Na+ channel and blocks K+ channel

Front 89

how do sweet, bitter and umani tastes work?

Back 89

g-coupled receptors

Front 90

what is the taste pathway?

Back 90

taste bud to primary gustatory area to brainstem to thalamus to cerebral cortex (G1)
taste terminates in subcortex: concious via thalamus unconcious vis hypothalamus

Front 91

what are the visual system 'language''s 4 basic features?

Back 91

-orientation (for form vision and perception of shapes)
-colour
-motion
-depth

Front 92

what are the 2 things the visual system requires?

Back 92

1. accurate representation of the visual field on the retina
2. point to point representation (mapping) of the retina in the primary 'visual nuclei' of the thalamus and primary visual cortex (V1) and associated cortex (V2-5)

Front 93

how do the eyes focus?

Back 93

cornea approx 3/4 of focussing
lens varies focus with ciliary muscle (lens relaxed for far, contracted for close)

Front 94

what do retinal ganglionic cells do?

Back 94

nerve fibres from ganglion layer assemble to form optic nerve

Front 95

what is the direction of light through the cells layers?

Back 95

-retinal ganglion cells
-amacrine cells
-bipolar cells
-horizontal cells
-photoreceptors (rods and cones)

Front 96

what do amacrine cells do?

Back 96

lateral inhibition at the level of the retinal ganglion cells

Front 97

what are bipolar cells?

Back 97

'on and off' cells.
connect photoreceptors to retinal ganglion cells

Front 98

what do horizontal cells do?

Back 98

lateral inhibition at the level of photoreceptors

Front 99

how much detail can the visual sytem resolve (visual acuity)?

Back 99

depends on density and type of cell present

Front 100

what is a receptive field?

Back 100

group of cells that a cell in the ganglionic layer receives signals from

Front 101

where is visual acuity optimal?

Back 101

foveal centralis (responsible for nearly all 'useful' vision, absence of inner retinal layes and local bv

Front 102

what is the ratio of receptors to ganglionic cells at the fovea?

Back 102

1:1
ganglionic cells mainly cones

Front 103

what is the ratio of receptors to ganglionic cells at periphery?

Back 103

1:1000 photoreceptors to ganglionic cells (mainly rods)

Front 104

what do rods detects?

Back 104

most sensitive to dim light, don't convey colour (low intesity vision - low acuity)

Front 105

when do cones work?

Back 105

work in bright light and are responsible for acute detail. black and white and colour.
high intensity vision - high acuity

Front 106

where do ganglionic cells project to?

Back 106

thalamus (LGN) visual perception
midbrain (superior colliculus) integrate visual and auditory info, reflexivly direct gaze to object of interest

Front 107

what does the suprachiasmic nuclei do?

Back 107

synchronises circadian rhythm with diurnal (day-night) cycle

Front 108

what does the pulvinar (thalamus) do?

Back 108

stabilises retinal image and maintains direction of gaze during head movement

Front 109

what are the connections of the retina to the CNS?

Back 109

-concious vision: to LGN to primary visual cortex to association visual cortex to association visual cortex
-unconcious vision: to suprachiasmatic nucleus to superior colliculus to pulvinar