Midterm 2 Flashcards
(87 cards)
1
Q
Proprioception (who came up with it, what is it, and 4 contributors)
A
perception of the body movement/orientation in space
- Sherrighton
1. sense of position and movement of limbs
2. sense of tension or force
3. sense of effort or heaviness
4. sensations of body image and posture
2
Q
kinesthesia vs proprioception
A
- kinesthesia: movement sense
- sense of movements
- behavioural
- conscious - proprioception: position sense
- sense of where the body is in space
- can be subconscious/reflexive
3
Q
types of proprioceptive afference and what is it
A
- signals generated by mechanoreceptors in response to stimulate that is produced as a consequence of the position and movements of body and tensions
1. ex-afference: generated from external source - unexpected
- external stimulation
2. re-afference: generated from own movements - ‘re-do’
- internally generated stimulation
4
Q
examples of matching tasks
A
- simultaneous:
- both limbs compared to each other
- target limb vs reference limb - successive:
- single limb compared to itself
- before vs after
5
Q
examples of discrimination tasks
A
- flexion vs extension
- was it moved? how far?
6
Q
what are the sources of proprioception
A
- muscle spindles: length/velocity of muscle
- GTO: tension/force of muscle
- joint: pressure, ligament force, point position
- cutaneous: length/velocity of skin stretch
- movement onset/offset
7
Q
what type of fibre does tendon vibrations activate
A
- type IA (IA = muscle lengthening, cutaneous = touching nose –> creates conflict)
- kinesthetic illusion
8
Q
pinocchio effect
A
- participant grabs their nose (cutaneous sensation)
- biceps brachii tendon is vibrated (sensation of arm extended)
- need to make sense of conflicting sensory info (nose is felt to grow bigger)
9
Q
sensory dominance (what are the soruces and an example)
A
conflict arises and brain chooses one sensation over other sensory information
1. muscle spindles
2. vision
- rubber hand illusion
10
Q
joint receptors (when it occurs and the types)
A
- occur after total joint replacement
1. lignocaine: joint receptor sensitivity decr (proprioception score decr)
2. dextran: joint receptor sensitivity incr (proprioception score incr)
11
Q
cutaneous receptors type SAII (what its role is within hand/finger proprioception)
A
- innervates ruffini receptors (detect sinstretch)
- SAII record on the back of hand during finger movements (flex/ext of fingers)
- SAII code for finger position:
- discharge rates corresponding with finger movements
- finger flex: SAII discharge rates incr
- finger ext: SAII discharges rates decr
12
Q
cutaneous receptors type FAI
A
- innervates meissner corpuscle (detect initial, rapid change in skin stretch)
- code for which joint is moving
13
Q
how is kinesthetic information obtained and what it requires
A
- signals are ambiguous from one proprioception alone
- combination of multiple inputs
1. all proprioceptors available
3. muscle receptors available
4. cutaneous, muscles, and joint receptors available
14
Q
what is efference role in proprioception
A
- motor command
15
Q
what are the three areas of the motor cortex
A
- premotor cortex
- supplementary motor area
- primary motor cortex (M1)
16
Q
what is the role of the premotor cortex and where does it relay info to
A
- selection of appropriate motor plans for voluntary movement
- preparing for tasks
- relays info to M1
17
Q
types of neurons in the premotor cortex
A
- motor-set neurons: some neurons signal preparation for movement (getting set)
- specific neurons for specific actions - mirror neurons: activated in response to sensory aspects associated with motor actions
- preparing for action
- respond to sight and sound of action performed
18
Q
what is the role of the supplementary motor area (SMA) and what does it respond to
A
- programming complex sequences of movements and coordinating bilateral movements
- based on remembered/previous sequence of movements
- responds to:
- sequence of movements
- mental rehearsal of sequences of movements
19
Q
what is the role of the primary motor cortex (M1) and another word for it
A
- motor homunculus: does not represent activity of indiv muscles
- elicits movements of indiv body parts involved in multiple muscles
1. force movement
2. direction of movement
3. speed of movement
20
Q
where does the M1 relay info to
A
- relays motor commands to the alpha MN via corticospinal MNs (corticospinal pathway)
21
Q
good spatial resolution vs good temporal resolutions
A
- spatial: high accuracy in determining WHERE something happens
- temporal: high accuracy in determining WHEN something happens
22
Q
recording techniques of the motor cortex
A
- electroencephalography (EEG)
- functional magnetic resonance imaging (FMRI)
- Transcranial magnetic stimulation (TMS)
23
Q
EEG (what it stands for, what it is, and the pros/cons)
A
- electroencephalography
- electrodes placed on the scalp, and record electrical activity underneath the electrode
- pro: excellent temporal resolution
- con: poor spatial resolution
24
Q
FMRI (what it stands for, what it is, and the pros/cons)
A
- functional magnetic resonance imaging
- measures blood flow within the cortex (compares deoxygenated blood vs oxygenated)
- neuronal activity involves metabolic demand (incr neuronal activity = incr metabolism = incr oxygen demand)
- pros: excellent spatial resolution
- cons: poor temporal resolution
25
TMS (what it stands for, what it is, and the pros/cons)
- transcranial magnetic stimulation
- selectively determines what region of the MC to investigate
- magnetic field causes depolarization of motor cortical neurons --> activation of muscles inn by those cortical neurons
26
tactile acuity ( and a test that will test this)
- ability to distinguish between two points
- small receptive fields permit high resolution of spatial detail.
- two-point discrimination test: minimum separation needed between two points to perceive them as two units (want the shorter distances)
- grating acuity test: placed a grooved stimulus on the skin and asking the participant to indicate the orientation of the grating
27
what cutaneous mechanoreceptor is responsible for tactile acuity
merkel cells (SA1)
28
what affects tactile acuity
- receptive fields (size)
- density of receptors
- representation within somatosensory cortex
29
where are the cutaneous receptor located in the hand
- tip of finger: high concentrations of SA1 (merkel) and FA1 (meissner)
- everywhere else: SAII (ruffini) and FAII (pacinian) are more equally distributed
30
____ field sizes correlate with ____ _____ acuity
receptive field sizes correlate with tactile spatial acuity
31
when does sensation and perception occur
- sensation: occurs when the peripheral receptors are stimulated
- perception: occurs when the brain interprets the sensory stimulation
32
role of the thalamus
- relay information from the sensory receptors to areas of the cortex
33
what are the two pathways that the peripheral nerve fibers travel in (where do they cross over and synapse then go where)
1. medial lemniscal: consist of large fibers that carry proprioceptive and touch information
2. spinothalamic: consists of smaller fibers that carry temp and pain information
- cross over the opposite side of the body, then synapse at the thalamus, then go to the somatosensory cortex (S1)
34
where does somatosensory information go
- ascends in the afferent tracts in the SC, then projects to primary S1 and parietal cortex
35
where is the primary somatosensory cortex located
located in a ridge of cortex (postcentral gyrus) which is found in the parietal lobe
36
somatosensory homunculus
- visualizes the proportional sensory perception mapping of the body surface in the brain
- amount of cortical tissue devoted to each body surface is proportional to the sensitivity of that part
37
tactile acuity in the fingers
- tactile acuity decr (threshold incr) from the index finger to the pinky, but the density of the merkel receptors are the same across fingers
38
basal ganglia role and structure
- subcortical 'structure': group of various distinct clusters
- modulate voluntary movement through facilitation or inhibition os signals descending from the motor cortex
39
what is the input and output of the basal ganglia
- input from the cortex (primary motor and frontal)
- output to pre-motor areas, SMA, PMC, FC all via the thalamus
40
what are the parts of the basal ganglia
- striatum
- globus pallidus (internal and external segment)
- subthalamic nucleus
- substantia nigra
all relay to the thalamus
41
how is the Basal ganglia organized
each nucleus is somatotopically organized
- neurons grouped by specificity of movemen
42
what are the BG neurotransmitters
1. GABA (gamma-aminobutyric acid) --> GABAergic neurons: are inhibitory
2. Glutamate --> glutamatergic neurons: are excitatory
3. Dopamine --> dopaminergic neurons: depends on the receptor it binds with (D1 receptors: excitatory --> involved in direct pathway, D2 receptors: inhibitory --> involved in indirect pathway)
43
types of pathways in the BG
1. direct pathway: neural pathway involving the BG to the initiation and facilitation of voluntary movement
2. indirect pathway: inhibits unwanted movement
44
draw the BG direct pathway
45
parkinsons disease
- progressive neurodegenerative disorder within the BG
- affects 1/100 adults >60yrs
- 1.5 x higher in males then females
- life expectancy: 10-20 yrs afte diagnosis
- no cure: treatments to target symptoms
46
what are the symptoms of parkinson's
4 main motor symptoms:
- resting tremors
- rigidity
- bradykinesia: slowness of movements
- parkinsonian gait
cannot initiate movement
47
what is responsible for parkinson's disease
- lewy bodies: abnormal aggregates of protein that displaces other cell components and disrupt cell function
- presented in the substantia nigra
- leads to death of neurons
48
pathophysiology for parkinson's disease (draw out pathway)
1. death of dopaminergic N in substantia nigra
2. reduced dopamine release
3. direct pathway cannot aid in initiation/facilitation of movement
4. parkinson's movement symptoms
49
cerebellum
- translates to little brain
- 10% of brain volume but 50% of brain neurons
- is our comparator: receives afferent (sensory) and efferent (motor) information, compares initiation vs what happened
50
functions of the cerebullum
1. maintenance of balance and posture
- making postural adjustments
- integrates sensory information relevant to balance and modulates information
2. coordination of voluntary movement
- coordinates timing and force of diff muscle groups
3. motor learning
- adapt and fine tuning motor commands
- trial and error
51
anatomy of the cerebellum
4 symmetyrical hemispheres:
1. hemisphere
2. vermis
3. intermediate zone
4. flocculonodular lobe
52
cerebellum pathways
1. spinocerebellar
2. cerebrocerebellar
3. vestibulocerebellar
53
spinocerebellar pathway (location, what it involves, and role)
- vermis and intermediate zone
- integrates sensory and motor information
- motor coordination
54
cerebrocerebellar pathway (location, what it involves, and role)
- lateral hemisphere
- involves cortical input
- planning and timing of movements
55
vestibulocerebellar pathway (location, what it involves, and role)
- flocculonodular lobe
- involves vestibular nuclei input
- posture and vestibular reflexes
56
how to tell if there is a dysfunction in the cerebellum and the symptoms
- decrease in size of the cerebellum
1. ataxia
2. dysmetria
3. hypotonia
4. large amounts of sway
57
ataxia
58
dysmetria
59
hypotonia
60
efference
motor command sent from MC to body
61
efference copy
copy of motor command used to update other brain regions on the action about to be performed
62
ex-afference
sensory information from an externally generated source
- unexpected
63
re-afference
sensory information from a self generated source
- expected
64
corollary discharge
- represents the re-afference we EXPECT to get from a self generated movement
- used to inhibit expected feedback from generated movement that may interfere with execution of task
- if there is unexpected afferent information it doesn't get inhibited and gets sent back to cortext to get updated
65
describe the steps of the feedforward model
1. movement goal is sent to MC and a plan is selected based on previous experience
2. efference (motor command) ent to the body to execute the plan based on previous experience
3. efference copy is sent to cerebellum to update on what is about to happen
4. corollary discharge is produced by the cerebellum to represent the excepted sensory feedback we should get
5. reafference is produced from the body to represent the actual sensory feedback we got from the expected movement
6. comparison of the corollary discharge occurs in the cerebellum
7. if doesn't match the cerebellum updates the motor cortex about the reafference information and adjusts the plan
66
what experiment shows evidence of corollary discharge
tit for tat experiment:
1. subject 1 has force exerted on their finger by motor
2. subject 1 now tries to replicate the same amount of force on subject 2's finger
3. alternating replicating force applied back and forth (force incr dramatically)
67
techniques used for cerebellum motor learning
- prism goggles: shift the visual field leftward
68
_____ is a limited cortical resource
attention is a limited cortical resource
69
divided attention
- multitasking
- ability to focus on multiple forms of sensory information
70
dual task paradigm
- given a primary task and a secondary task that they need to perform simultaneously
- performance of both tasks will be worse than if performed separate
71
selective attention and the types
ability to focus attention on one specific task
- exogenous: external, reflexive (focus on objects/stimuli that stands out)
- endogenous: internal,voluntary (incorporates intention, goal orientation, previous knowledge)
72
blindness and the types
due to attentional demand, can experience types of 'blindness' to your environment
- inattentional blindness: miss something completely
- change blindness: don't notice something has changed but aware of it originally
73
primary visual cortex (V1), and how is it arranged
- located in the occipital lobe
- arranged retinotopically: specific groups of neurons represent/respond to specific parts of our visual field
74
where does the V1 receive info and where does it project to
- receives visual signal from eyes
- passes through visual association areas
- relays info to two primary areas
75
where does visual information pass through
- visual information passes through the lateral geniculate nucleus (LGN) (within thalamus) and relayed to cortical areas
76
two stream hypothesis
1. secondary somatosensory cortex (involved in dorsal stream)
2. inferotemporal lobe (involved in ventral stream)
77
secondary somatosensory cortex
- located in post parietal lobe
- in complex movements: confirm what movements have already occured and decides what to come next
78
inferotemporal lobe
- involved in visual memory
- role in object recognition
- helps understand complex. stimuli like faces and sense
79
dorsal stream
- object location and motion
- detecting and analyzing movements
- spatial awareness and guidance in action
80
what disorder occurs in the dorsal stream
- apraxia
- damage to secondary somatosensory cortex
- movement disorder which impairs ability to perform task s or movements
- doesn't impair ability to plan or execute but disrupts how they are performed
81
ventral stream
- object recognition and form representation
82
what disorder occurs in the ventral stream
- visual agnosia
- damage to the inferotemporal lobe
- disorder which impairs the ability to recognize objects
- doesn't impair ability to see object but recognize what it is used for
83
where do the ventral and dorsal streams project to
the prefrontal cortex
84
prefrontal cortex
- decision making centre of the brain
- decides what response you want to have to your environment
85
where does the prefrontal cortex project to
the premotor cortex
86
premotor cortex
- help plan a movement
- project to the pother motor areas to carry out desired movement
- deciding on response and ability to carry out the response are influenced by the amount of attention you are paying to the task
87
draw out the pathway that would occur for seeing an object then wanting to pick it up
