Midterm/Final - 5309

Describe the methods and findings of Bridgeman et al.'s study on disconnection b/t verbal and memory reports

*METHODS* - screen shows stationary X, frame moves left, giving impression X moved right - display taken away, asked subject where target was *FINDINGS* - subjects would still point where target was/is - would verbally report 'X appears to move right', but still accurately point to remembered location

What are the 3 types of interference when performing 2 tasks?

1. Peripheral: eg. need to look in 2 directions @once; need to use same hand for diff tasks 2. Similarity: 2 tasks both need overlapping mental resources (eg. both audiovisual tasks) 3. General attn capacity limit: less anticipation and prob-solving; switch costs when alternate

What is a process model under the context of Schmidt's Law? (see packet for graphs)

• People use a stereotypic force pattern w/adjustable force magnitude and duration parameters (ie. a generalized motor program) • Variation in force magnitude and duration leads to spatial endpoint variability (We) • There are no corrective submovements for these very brief movements

What are Propioceptors? Name the five types discussed in class

• Position, mvmt, and force sensing of our bodies 1. vestibular system 2. muscle spindles 3. golgi tendon organs 4. joint receptors 5. cutaneous receptors

What are triggered reactions? Autogenic or not? Time-scale? What are they similar to? What do they bypass?

• Pre-structured, coordinated reactions made up of coordination of different muscles - rapid responses to propioceptive perturbations (eg. wine glass slipping while going to take a drink) • Non-autogenic, 80 - 120 ms latencies • Similar to a fast rxn time, w/o some of the stages of info-processing - bypasses delay of cortical, deliberate rxn time

Describe myotatic reflexes: autogenetic or not? How long is the loop time? What structures are involved? Can they be modified by instructions? (Give eg.) Can they be affected by the number of choices?

• Single synapse, spinal cord to motor neuron single reflexes • Autogenetic • Loop time: 30-50 ms • Structures involved: spindles, gamma loop, same muscles • CANNOT be modified by instructions - eg. patellar reaction, no way to inhibit this • CANNOT be affected by # of choices

What does the Spring model of control imply, and what does this model not require? Which model of control does this differ from and how?

• Spring model implies co-activation of agonist and antagonist as opposing springs - doesn't require feedback • Different from model of control suggested by Schmidt's law, which modeled the arm as a mass moved by accelerating and decelerating forces

What kinds of changes did Goodale & Servos (1996) find to affect reaching and grasping?

• Sudden changes in location of object affect both • Sudden changes in size and orientation affect both

How do you estimate time to contact (Tc) as a function of retinal image size (A) and rate of change of A (Å)?

• Tc is inversely related to (Å/A), which itself is the relative rate of change of A • see last pg. of 1/15 packet for visual info

What were the findings of Allard et al.'s and Starkes & Deaken's studies on whether the pattern of expert-novice difference generalize to other contexts?

*Allard et al. - Basketball recall* - structured situations: set plays - unstructured situations: pursuing loose ball - varsity > intramural players @ reconstructing set plays, no diff. in recons.g unstructured *Starkes & Deaken - Field Hockey recall* - same just w/field hockey pm

Describe the findings of both Bourne & Archer's and Baddeley & Longman's studies on distributed practice

*Bourne & Archer's pursuit rotor task* - 60s rest group > 45s > 30s > 15s > no rest during transfer trials - could be due to physical or mental (preventing learning) fatigue *Baddeley & Longman's postal keyboard* - 1hr/day, 1sesh/day (1 x 1) > 2 x 1 > 1 x 2 >>> 2 x 2 - basically massed practice condition did worst during retention (others distributed

Describe the methods and findings of Shea & Upton's study on interpolated activities during KR intervals for a linear positioning task

*METHODS* - 2 groups: 1. filled KR-delay: do some other mvmt during 30s delay 2. unfilled KR-delay *FINDINGS* - @end of prac: unfilled >> filled - transfer trials: unfilled >> filled - unfilled 30s allows for rehearsal/enhanced acquisition of task peformance

Describe the methods and findings of Howell's 1956 study on augmented KP of force patterns (kinetics) at the start of a sprint

*METHODS* - 2 groups: experimental (given augmented fdbk) and control - ideal force pattern maintains high constant force until push off blocks (rect.r r-ship b/t front foot pressure and time on blocks) *FINDINGS* - experimental improves faster than control, and eventually shows rectangular mvmt pattern, unlike control which doesn't learn this by trial 10

Describe the methods & findings of Hird et al.'s study on mental and physical practice

*METHODS* - 2 tasks: pegboard (insert diff pegs into corr.g holes) and pursuit rotor (tracking target on circ.r track like record) - 6 groups: 100% phys., 100% ment., 75P:25M, 50:50, 25P:75M, no practice control *FINDINGS* - pegboard: 100P > 75P:25M > 50:50 > 25P:75M > 100M > control - pursuit: 75P:25M > 100P > 50:50 > 25P:75M > 100M > control - physical prac generally leads to greater chg than mental or mixed - still some benefit to mental prac tho

Describe the methods and findings of Fleishman & Rich's study on how different abilities may limit performance @ difft stages of learning

*METHODS* - 2-hand coordination task: turn 2 cranks to following a moving target, circular pattern - Kinesthetic sensitivity groups: high and low - Spatial measure groups: high and low *FINDINGS* - by end of trials, KH > KL, but no difference seen b/t SH and SL - relative influence of kinesthetic sensitivity seem to increase as fcn of prac (more haptic reliance later in prac); opposite seen for spatial measure

Describe the methods and findings of Armstrong's study on physical guidance vs knowledge of performance in producing a back-and-forth mvmt

*METHODS* - 3 groups: 1. Terminal KP: KP given @end of trial; shown correct pattern after every 15th trial 2. Concurrent KP: visual display of where target was & where mvmt was in real time to error correct 3. Guidance: system physically corrected mvmts proportional to size of error *FINDINGS* - guidance did best during practice, but during transfer terminal >> concurrent > guidance - concurrent and guidance never really learned entire pattern due to instantaneous fdbk, so when fdbk removed had no pattern to transfer

Methods and findings of Shea & Kohl's study on the variability of practice in a force production task

*METHODS* - 3 groups: 1. criterion + variable: exp. forces both stronger + weaker than criterion 2. criterion + criterion 3. criterion only *RESULTS* - criterion and criterion+criterion better throughout practice, but in retention (1 day delay) criterion + variable much better bc have built up range of possible forces while others only practiced one

Describe the methods and findings of Lavery's study on summary vs immediate KR in propelling a ball up a track to a target

*METHODS* - 3 groups: summary KR, immediate KR, and both *FINDINGS* - immediate and both conditions acquired skill quicker and performed much better during learning - summary outperformed immediate and both during transfer however - S built up own ability to self-critique - B showed that even when receiving S fdbk, also receiving I fdbk brings performance down to level of I in transfer trials

Describe the methods and findings of Klapp et al.'s study on whole-task vs part-task training of a 3:2 bimanual polyrhythm

*METHODS* - 4 groups did 4 diff.t polyrhythms: 1. 3:1 (separate) 2. 2:1 (separate) 3. 1:1 (separate) 4. 3:2 (integrated) *FINDINGS* - only integrated-taught group actually performed the 3:2 rhythm, separate-taught could only perform simpler rhythms

Describe the methods and findings of Schmidt et al.'s study on summary KP for diff. #s of trials in an anticipation timing task

*METHODS* - 4 groups of varying summary length: 1 trial, 5 trials, 10 trials, and 15 trials *FINDINGS* - at end of prac: 1T > 5T > 10T > 15T - immediate transfer: 5T > 1T > 10T > 15T - delayed transfer: 5T >> 1T > 10T > 15T - 15T doesn't overcorrect, but not enough info for adequate correction - 1T overcorrects, too much noise - 5T: happy medium, adequate correction

Describe the methods and findings of Bilodeau et al.'s study on augmented KR in a blindfolded linear positioning task

*METHODS* - 4 groups: No KR; KR every 2 trials; KR-6; KR-19 - 20 prac trials, then five transfer trials where all groups receive KR *FINDINGS* - No KR didn;t improve performance and also didn't seem to learn anything - KR seems essential to this task

Describe the methods and findings of Yao et al.'s study on average vs summary KR in an anticipation timing task

*METHODS* - 5 groups: 15T avg, 15T sum, 5T avg, 5T sum, KR on each trial *FINDINGS* - @end prac: ea. > 5-avg/sum > 15-sum > 15-avg - after 10 min: 5-avg/sum >> 15T-avg/sum > ea. - after 2 days: 5-avg/sum > 15-avg > 15-sum > ea. - 5T > 15T, average barely better than summary (tendency to attend to central tendencies more than variability)

Describe the methods & findings of MacKay & Bowman's studies on mental and physical practice in bilingual transfer

*METHODS* - German-English bilinguals repeatedly practice a sentence in one lang., then transfer to sentence in other lang - practice either overt(P) or covert(M), words either scrambled or in sentences *FINDINGS* - mental > physical in overt transfer, possibly due to fatigue from overt prac. - having practiced scrambled is like retaining no practice, but sentence group showed marked improvement - scrambled lack well-developed, conceptual organization that aids in transfer

Describe the methods and findings of Jagacinski & Hah's study on tracking a repeated pattern w/ and w/o a secondary task

*METHODS* - Primary task: manually tracking visual signal - Secondary task: vocally report an auditory set of #s after finishing tacking *FINDINGS* - avg tracking error kept same shape (r.ly same as velocity) throughout practice, just got smaller - secondary task increased error again on day 10 due to cognitive interference

What were the methods and findings of Lee & Magill's study on blocked vs random vs serial practice schedules for a discrete mvmt task?

*METHODS* - Procedure: 3 lights come on, knock over 3 out of 6 blocks that correspond to the lights - 3 groups: 1. Blocked: blocks of same trial, know what's coming in ea. block 2. Serial: repeating sequence of lights 3. Random *RESULTS* - all improved w/practice - no diff. b/t random & serial, but blocked better during practice (knew what coming) - blocked did much worse than others after break, showed poor retention

Describe the methods & findings of Kernodel & Carlton's study on augmented KP with videotapes

*METHODS* - Task: throwing w/nondominant arm, close eyes on release of ball; 5 test sessions - 4 groups: 1. video + correction cues: compared to standard, eg. shown correct hip mvmt 2. video + attn cues: eg. look @ your hips 3. video: shown self throwing 4. KR: told distance thrown *FINDINGS* - by fifth test session: video + correct > video + attn > video & KR

Describe the methods and findings of Huttermann et al.'s study on attention and sports

*METHODS* - control: one target position - experimental: two positions w/various degree of spatial (H or V) separation - receive pre-cues (1000ms), then cue(s) (1400ms), then answer how many certain shape @either position *FINDINGS* - experts in horizontal sports better attn. when cues had more horizontal separation - experts in vertical sports better attn. when cues had more vertical separation

Describe Decety & Jeannerod's test of Fitts' Law in imagined mvmt of walking through gates of varying width and distance away

*METHODS* - gates of varying dist/width presented in VR, then blanked away, then subjects told to imagine walking through the gate then signal once done *FINDINGS* - mental mvmt time and ID of gate dist/width showed Fitts-like r-ship - when using mental imagery, one is using some aspects of processes used in mvmt generation to generate the imagery; overlap in mental imagery and mvmt generation processes

Describe the methods and findings of the reaction time keyboard task used to test Ackerman's theory

*METHODS* - given stimuli either compatible w/keyboard (#s) or incompatible/difficult to map (UL,LR) - given comp. during training, incomp. during transfer - measured correlation b/t RT and ability *FINDINGS* - during training, higher correlation b/t perceptual speed ability and RT than cognitive ability and RT bc task too easy don't need eval. - in transfer, reverse to higher correlation b/t cognitive ability & RT at first for eval., then correlation b/t perceptual speed ability and RT catches up w/practice

Methods & Findings of McCracken & Stelmach's study on variability of practice in hitting a barrier in 200 ms

*METHODS* - had to move some distance to knock over a barrier, test distance = 50 cm; 2 groups: - constant dist.: 15 or 35 or 60 or 65 cm - variable dist.: 15 and 35 and 60 and 65 cm *RESULTS* - constant > variable during 30 prac trials, but variable > constant both during immediate and delayed transfer tests

Methods and findings of Landin & Hebert's study on short blocks of repeated trials of basketball shooting

*METHODS* - nocontest shots from 5 diff positions, 3 groups: 1. Blocked - 6 cons. shots from one position 2. Short blocks - 3 cons. shots from 1 position 3. Serial - change position after each shot - 3 days prac, posttests of blocked, serial, and free throw *RESULTS* - 'short blocks' did better than both serial and blocked in posttests bc SB allows for more error correction than serial, and more variation than 'blocked' during practice

Describe the methods and findings of McCullagh & Caird's study on expert vs learning models in a timing task

*METHODS* - perform some mvmt, 3 groups 1. Correct model - just watching correct model performed by an expert 2. Learning model (no KR) - no critique/KR 3. Learning model (w/KR) - get fdbk from person doing task in video *FINDINGS* - LM w/KR >> LM w/o KR >> Correct model - watching someone learn task & correct mistakes led to better performance than watching someone do task perfectly - learn more from watching someone struggle w/task and get feedback

Describe the methods and findings of Pew & Wickens' study on learning to track a repeating segment

*METHODS* - pursuit tracking task, first 1/3 randomly generated, second 1/3 always the same, last 1/3 random from trial to trial - ppl get better at middle 1/3? if can verbalize what pattern was (recog. repeating middle)? *FINDINGS* - no one verbalized middle segment repeated, but still improved on middle segment faster than other segments - implicitly learned something about pattern

Describe the methods and findings of Lee & Carnahan's follow-up of Sherwood's study of the 200 ms elbow flexion task (asked if bandwidth effect due to omission of fdbk serving as implied fdbk or no)

*METHODS* - same task as Sherwood, now 2 subjects: 1. Subject 1 - only gets KR when outside BW 2. Subject 2 - only gets KR when S1 gets KR - both get KR on same % of trials, decreasing w/practice *FINDINGS* - S1 > S2, so effects not due only to gradual reduction of fdbk - Therefore findings from Sherwood not due to lack of KR serving as implicit fdbk, but rather overload of KR in 0% BW condition

Describe the methods and findings of Boyce's study on goal setting in a shooting task

*METHODS* - shooting task, 3 groups: 1. participant-set goals 2. experimenter-set goals 3. "do-your-best" goals *FINDINGS* - participant- and experimenter-set goals > do-your-best goals during retention test - better to set concrete, numerical goals r/t than just "do my best"

Describe the methods and findings of Todorov et al.'s study on augmented KP of kinematics in a ping pong task

*METHODS* - task: ball comes down chute, need try to hit it over 1st net, through 2nd net, and onto platform - 3 training conditions: 1. standard coaching (control) - coach tells person how to adjust, swing better, etc. 2. simulator w/invisible ball - see racket of expert, try to match paddle to this mvmt; own paddle mvmt also uploaded to show deviation 3. simulator w/ball visible - same but see ball *FINDINGS* - in terms of improvement, simulator w/ball > standard coach > simulator w/o ball

Describe the methods and findings of Chen et al.'s study on muscle exertions (bicep curls) in VR

*METHODS* - task: mimic bicep curls in VR - displayed either as vertically moving line (2D) or something that looked like your hand grasping a dumbbell (3D) - actual physical lifts served as control *FINDINGS* - higher tricep activity to resist bicep activity in both VR conditions -- creating mental sim of lifting actual weight - tricep activity much higher in 2D than in 3D

Describe the methods and findings of Schmidt & White's study on error detection in a 150 ms ballistic timing task

*METHODS* - task: move past a marker in 150 ms - measured correlation b/t objective error and subjective estimation of error *FINDINGS* - gradual increase in correlation across acquisition, then sharp increase during transfer - building up r-ship b/t what mvmt 'feels like' and what's actually happening - strengthening of recognition schema w/practice

Describe the methods and findings of Sherwood's study on the bandwidth of KR in a 200 ms elbow flexion task

*METHODS* - task: need to flex elbow to specified position in exactly 200 ms - 3 conditions: 1. 0% BW: KR always given (unless do perfect) 2. 5% BW: KR only given if +/- 10ms off 3. 10% BW: KR only given if +/- 20ms off *FINDINGS* - all perform equally by end of prac trials, but in retention (where no KR given) 10% > 5% > 0% - 0% became overly dependent on fdbk, never actually learned the skill, outsourced this to expr - 5% and 10% build up intrinsic fdbk that's used to perform skill; create self-critique/internal rep.n of what good performance is

What were the methods and findings of Hall et al.'s study on blocked vs random batting practice for college baseball players?

*METHODS* - three conditions: 1. Random: don't know what the pitch will be 2. Blocked: 15 fb's, 15 curves, 15 change-ups; know what pitch will be 3. Control *RESULTS* - random did worse than blocked during practice session, but random > blocked during testing, both when pitches were random and blocked

What are the 3 phases of Ackerman's 1988 theory of stages of learning?

*Phase 1: Cognitive phase* - evaluate difft strategies; figure out what to do - general cognitive ability, early in practice *Phase 2: Associate phase* - refine selected perceptual and motor patterns - match perceptual to motor patterns *Phase 3: Autonomous phase* - less interference from other activities - highly correlated later in practice, once have evaluated cog. strat.s and refined perceptual-motor patterns

What is the Power law of practice? (express equation in 2 ways, and explain it w/in context of practice over time)

*RT = a / P^b* *Log(RT) = Log(a) - b(Log P)* - where RT = rxn time; a = RT on trial 1; P = trial #; b = learning rate - reflects v.quick improvement early in practice, and v.slight/gradual improvement later in practice

What did Vereijken et al. find in their ski simulator study? In relation to this, what is the Bernstein perspective?

*Vereijken et al.* - person prac.d skiing on track, horizontal B&F - frequency and amplitude poor at first, then gradually/continuously improve - range of joint angles (knee, hip, ankle) all increase across practice *Bernstein perspective* - keep degrees of freedom low when first learning/training, then increase them with more practice

How are performance limits on pattern generation and tracking different? What does this suggest about the interplay of perceptual, cognitive, and motor functioning?

- *Pattern generation:* drawing circle and square simultaneously shows strong interference (competing patterns to guide mvmt of ea hand) - *Tracking:* haptically tracking circle and square simult.ly shows little interference - we can do the mvmt (see tracking), but can't generate the pattern -- therefore difficulty lies in cognitive/perceptual domain r/t motor domain

How do the stance and swing phases change when an animal goes from a walk to a run/trot?

- *stance*: big change -- much shorter for run/gallop than walk, increases at constant rate as cycle time increases - *swing*: little change -- slightly shorter for run/gallop

What did Strayer et al. find in their study of driving w/a hands-free cell w/high traffic density?

- 3 vs 0 accidents - 179 ms longer to onset braking - 510 ms longer to slow down - follow lead car 11.5 ft further back - 11.5ft/179ms only = 44 mph, which is slower than "highway speed", so not lagging enough to compensate for later braking

Define knowledge of results (KR) vs knowledge of performance (KP)

- KR: post-mvmt info about the outcome of the mvmt in the environment - KP: post-mvmt info about the nature of the mvmt pattern

What are some properties of motor programs according to Wright (1990)?

- Plans for generating movement (existing prior to start of mvmt) - Mental rep.ns that bridge the processes of planning and control (and may incorp. fdbk) - Analogous to computer programs - Not available to introspection - Possibly hierarchical

What is the Progression-Regression hypothesis?

- Practice leads to greater use of velocity &/or acceleration cues -- more anticipation - Stress results in lesser use of velocity &/or acceleration cue -- less anticipation - lead to mvmt pattern that looks like binary threshold fcn

What time do Woodworth, Posner & Keele, and Zelaznik et al. respectively say it takes to process visual feedback?

- Woodworth: about 250 ms - Posner & Keele: 190 - 260 ms - Zelaznik et al.: ~150 ms

What is schema theory?

- akin to schema, empirically derive rules that generalize motor program parameters, initial conditions of limbs, and mvmt outcomes - like fitting a regression line to estimate/generalize multiple, weighted individual mvmts

What is a possible design for a spinal pattern generator proposed by Schmidt et al. (2019)?

- alternation b/t flexors and extensors builds up a cyclic movement/pattern - higher centers input a motor plan, coupling among different oscillators generate different patterns which are adaptive based on speed

What is an efference copy? What is the time-scale?

- copy of action command sent to higher centers to evaluate relative to mvmt intention and/or subsequent fdbk - very rapid correction of ongoing mvmt (90 ms)

What did Jones find when he measured the performance of a large # of subjects and correlated every trial w/every other trial across individuals?

- correlations become higher w/practice - may be experimenting w/use of variety of abilities @first, then when figure things out settle on a few useful abilities/skills

Describe the findings of William James' 1980 study on peripherally triggered chains of responses

- during initial learning, successive responses are controlled by environmental stimuli (ie. ES1→R1→KS1; ES2→R2→KS2; etc) - as learning progresses, responses become conditioned to the kinesthetic fdbk from the preceding response (ES1→R1→KS1→R2→KS2→R3→KS3→etc.)

What are recognition schema, and for what two purposes are they used?

- empirically derived rules relating sensory consequences, initial conditions of limbs, and mvmt outcomes 1. used for terminating slow mvmts 2. used for evaluating fast mvmts

When one makes a rapid lane change from R to L, how does the steering wheel rotate? What trajectory does this follow, and what's being manipulated?

- first to left, then right, then back to left - circular trajectory, basically manipulating lateral acceleration (commanding rate of change of heading)

Describe Schmidt & Lee's study on mvmt responses to noxious stimuli in spinal frogs. What did they find, and what does this suggest?

- frog still raises limb to try and knock/wipe off noxious stimuli - either lowerbrain/spinal cord is responding reflexively to stimuli, still taking into account the position of the elbow -- levels of intercommunication exist within the spinal cord

Describe the findings of Crespo & Reinkensmeyer's study on physical guidance in learning to steer a simulated wheelchair

- guidance-as-needed and fixed guidance both improved more quickly than no guidance - FG showed sharp regression when guidance removed at trial 20, but then gradually improved again

How can anticipation overcome time delays in responding and thus produce a shorter "effective time delay"?

- if one's moving quickly, would need to anticipate target position to be further out in front of them, accordingly - like aiming projectile at moving target

What argument did MacKay and Keele make regarding mental and physical practice of language?

- mental practice is practicing conceptual level - physical is practicing phonological aspect

How can a timing parameter be conceptualized as a function of practice?

- parameter estimation is a "filtering problem" - averaging over N trials to get a reliable estimate - ignoring earlier trials that no longer reflect the current parameter value

What are the Golgi tendon organs?

- sensory receptors that respond to changes in tension - prevent injury from excessive contraction

Describe Rack & Westbury's (1969) study on spring-like r-ships b/t muscle tension and length

- set muscle length (or angle of ankle) by electronically stimulating anesthetized cats and measuring muscle tension - found Hooke-like behavior b/t muscle length and tension

What is the function of gamma motor neurons?

- set reference level of position and velocity that muscle should expect - adjust the sensory element

What kind of a relationship can a spring be described as? What does tension increase with, and what does the slope of tension vs length indicate?

- spring can be described as r-ship b/t tension and length - tension increases w/length (amt of stretch away from the spring's resting position) - for linear springs, the slope indicates the stiffness of the spring

What type of reflex is seen when a light touch to the top of the foot is made during either the stance or swing phase? What does this show about reflex modulation?

- stance: increased flexion - swing: increased extension or no change - reflex is modulated by what phase of the pattern agent is currently in in an effort to protect the overall pattern -- where sensory fdbk factors into cyclical models

What are submovements? When are more submovements required?

- submovements are a strategy for dealing w/perceptual-motor noise - more submovements are required for very precise movements

How may the power law of practice result from chunking?

- successive chunking of multiple stimuli-response options, gradually down to one unit, decreases how times each pattern is practiced accg. to power law - eg. 10 1-light -> 1-finger patterns each prac.d on 1/2 of trials in a block, next chunk 1/4, then 1/16, etc.

What is part-task training beneficial and not beneficial for?

- tasks w/long serial structure - tasks w/a natural pause - NOT w/very brief tasks governed by single motor program

How does proportional variability in force magnitude and duration underlie schmidt's lie?

- the standard deviation of duration is proportional to the mean duration - the standard deviation of force is proportional to the mean force magnitude - idek man look at the packet i guess

How do the varying functions of the dorsal and ventral visual streams put the findings of Bridgeman et al. (disconnect b/t verbal and memory) into a neuroscientific context?

- visual info splits off 2 ways: to parietal lobe via DVS, and to temporal lobe via VVS - *DVS:* "Where is it?", more connected w/mvmt (pointing to where target was, spatio-temporal info) - *VVS*: "What is it?", conscious, verbal description of target location (object recognition) - Back to Bridgeman et al.: tricked VVS, DVS separate so not tricked in same way

How do horses group their legs when walking vs trotting and galloping?

- walking: diagonal grouping - trotting/galloping: front-back galloping

What occurs during an Alpha-Gamma coactivation and to what end?

- when an alpha motor neuron fires, the muscles contracts and shortens - the gamma motor neuron will also fire to maintain the stretch of the spindle

What is the "closed-loop" system of motion? Define each step and component of it. (5)

1. System goal feeds input into reference mechanism - reference mechanism is the target trying to reach 2. Reference mechanism feeds error into the executive level - executive level contains the commands to be carried out by the muscles 3. Exec. level feeds instructions into the effector level (the muscles/actuators) 4. Effector level sends output to environment 5. Environment provides visual feedback back to reference mechanism

When is relative independence more prevalent in 3-part tapping (4 v 3 v 2) in drummers?

1. at faster speeds 2. for hand-foot than hand-hand (larger spatial separation)

What are the two components of driving/steering a car in terms of the visual cues?

1. error correction - matching the curvature of the car's path to the curvature of the upcoming roadway 2. planning - project the car's heading into the future (look-ahead distance) to predict and correct lateral position error

What part of the target width (W) does the effective target width (We) comprise?

Approximately 4 standard deviations

Describe the information processing models of responding to discrete stimuli (look at 1/24 packet for more on this, as well as ch.6 of text)

Stimulus presentation → stimulus identification → response selection → response programming of sequence and timing

What is the theoretical speed limit of walking?

V2max = rg, where r = leg length, g = gravitational constant

How do generalized motor programs work? (look at 1/29 packet for more on this, as well as relevent part of textbook -- hard to put into this)

have adjustable parameters for - speed (duration) - size and/or force - limb (muscles) - sometimes the adjustment is uniform across the whole mvmt pattern, sometimes not

What is the golgi tendon reflex?

inhibitory, protective mechanism causing relaxation reflex to prevent pulling muscles from excessive contraction

What is the general finding of studies of sensory interfered movements due to deafferentation? (see 1/22 packet and ch.6 of textbook)

response is about what one would expect from normal person -- see 1/22 packet for more info on these studies in general

What are muscle spindles?

sensors embedded in muscle

What type of control device did Epps (1986) find was best for text editing?

trackball, which slightly edged out the standard mouse in terms of MT vs ID

What is the range of time needed to use ball trajectory info to adjust hitting performance in table tennis, tennis, and cricket? In effect, the time to process visual feedback in sports. What may longer times be influenced by?

• 105 - 190 ms • longer estimates may be influenced by weight of bat/racquet

What does the visual image of a ball moving directly toward you look like when it's accelerating, rising at a constant velocity, and decelerating?

• Acceleration: ball rises vertically at accelerating rate • Constant velocity: ball appears to rise at a constant velocity • Deceleration: ball appears to rise at a decelerating rate

Describe long-loop reflexes: autogenetic or not? How long is the loop time? What structures are involved? Can they be modified by instructions? Can they be affected by the number of choices?

• Autogenetic • Loop time: 50 - 80 ms • Structures involved: spindles, cortex or cerebellum, same muscles • CAN be modified by instructions • CANNOT be affected by # of choices

Describe the findings of Hartzell et al.'s 1982 study on evaluating different displays for helicopter control?

• Discrete change in altitude rate on the right display, and moving the collective with the left hand, had much lower MT vs ID than discrete change in airspeed on left display, with moving cyclic w/right hand • i have no idea what i'm talking about, look at the packet i dont know

Describe Dewhurst's 1967 study on the multi-component response to an external force. What three phases are seen, and what time scale is each on? What is the important takeaway from this study?

• Dropped a weight into P's palm, P was to return hand to position from before, measured EMG activity in biceps over span of this movement • Three components seen: 1. Initial myotatic reflex (30 - 50 ms) - autogenic, irresistable due to quickness 2. Long-loop reflex (50 - 80 ms) - autogenic, functional stretch reflex - spindle info going up to higher levels then coming down w/minimal processing - resistable, greater EMG activity than myotatic 3. Reaction time component (120+ ms) - highly modifiable, intentional movements - more info processing at cortical levels - non-autogenic • Key point: shows simple mvmts are composed of diff.t reflexes on diff.t time-scales

Describe the mass-spring (equilibrium-point) model of limb movement

• Equilibrium occurs when the torque (tension x distance from joint) in the flexor is equal and opposite to the torque in the extensor • A change in the flexor muscle activation changes its springiness: - a change in the resting length - an increase in the stiffness of the muscle • The limb comes to rest at a new equilibrium pt.

What are the 3 functions of reflexes, and the underlying structure?

• Functions 1. Protect mvmt pattern against small perturbations (enhance stability) 2. Provide very rapid response 3. Maintain the springiness of a muscle • Structure - represented as Stimulus-Response at high level of simplification, underlying physiology reveals feedback loops

What evidence is there for integrated coordination of a 3 vs 2 polyrhythm?

• Holistic training is better than part-task training - better to learn 3+2 r/t 3 & 2 separately then combine • Lack of general skill transfer to other polyrhythms - can't easily transfer capability of 3+2 to 4+5, etc.

What are the effects of the springiness of the running surface, and how then is running speed defined?

• Increasing stiffness (hard surface) lowers contact time (Tc) and step length (L) • Decreasing stiffness (soft surface) increases the contact time (Tc) and step length (L) • Running speed = V = L/Tc

Describe Li et al.'s 1966 study on the roll axis control of an aircraft. What were there findings/takeaways?

• Method: akin to a "rotating room", see how quickly pilot can sense vertical deviations and make adjustments in different conditions (visual vs vestibular vs combined fdbk) • Results: as task increased in difficulty (divergence frequency increased), visual-only condition did much worse than both vestibular-only and combined conditions, which themselves did about equally well

Describe Woodworth's 1899 study on visual feedback in movements. Under what conditions did he find that visual feedback aided in movements?

• Method: metronome, paper moved under pen? - two conditions: eyes open and eyes closed • Found that eyes open condition only benefitted from visual feedback for movements of 250 ms or more - movements of 215 ms or less did not benefit from visual fdbk

Describe the study on deafferented monkeys as evidence for the equilibrium point model

• Method: monkey in the dark, w/no vestibular sense turns its head twd a target light that is darkened as soon as movement begins - kinesthesis surgically removed -- no sensory fdbk to indicate head position • Results: Target position is achieved after a force perturbation, as well as when a weight is added to the head • Argument: commanded a certain characteristic to the muscles, competing forces bring muscles back to equilibrium point

Describe Lee & Aronson's Moving room experiment. What did this show about vision's role in balance in both adults and children?

• Method: move walls of an experimental room w/a fixed floor • Results: - induces sway in adults - induces enough sway in children to induce falling - fall toward the wall if it moves away from them, fall away from the way if it moves twd them • Takeaways: - regulating posture by visual deviations of the wall - visual input is more important than mechanical when just learning to balance (children)

What mixture of skills are involved in reaching for something? What two signals are involved? (Arbib, 1990)

• Mixture of perceptual skill and motor skill • Activation signals and control signals

Describe Reaction time: autogenetic or not? How long is the loop time? What structures are involved? Can they be modified by instructions? Can they be affected by the number of choices?

• NOT autogenic • Loop time: 120 - 180 ms • Structures involved: various receptors, higher centers, any musculature • CAN be modified by instructions • CAN be affected by # of choices

Describe Triggered reactions: autogenetic or not? How long is the loop time? What structures are involved? Can they be modified by instructions? Can they be affected by the number of choices?

• NOT autogenic • Loop time: 80 - 120 ms • Structures involved: various receptors, higher centers, and associated musculature • CAN be modified by instructions • CAN be affected by # of choices

What are the respective functions of the otolith organs and the semicircular canals of the vestibular system? What are the 2 otolith organs?

• Otolith organs: provide info about orientation w/respect to gravity - also sensitive to overall direction and rate of spin - utricle and saccule • Semicircular canals: 3 fluid-filled half circles that sense particular directions of mvmt as well as rotation - also sensitive to force and acceleration, both internal and external

What is the Proportional Duration model? How can one test it?

• PDM: as movement becomes faster/slower, all aspects/components of movement become faster/slower at proportional rates • Test it by looking at video of the movement in slow motion -- if looks same just slower, PDM holds, but if mvmt looks irregular, mvmt doesn;t follow PDM

Describe Posner & Keele's 1968 study on visual feedback and movements. What movement times did they estimate benefitted from visual feedback?

• Participants had to make single discrete movements to some target, lights would go out on some trials • Estimated movement time to benefit from visual feedback was 190 - 260 ms

How do people deal w/the complexity of tapping polyrhythms (ie. 3 vs 2)?

• People mostly integrate the two rhythms into 1 coordinative unit (ie. not-di-fi-cult) • Perform the 2 rhythms relatively independently, (2 coordinative units), for very fast tapping (by concert-level pianists)

What are the three visual cues used for altitude control in helicopters? What is each sensitive to?

• The optic array: 1. *Global optical density*: the sparseness of texture elements w/in the field-of-view - the texture is denser when the height is high - sensitive to altitude disturbances 2. *Optical depression angle*: dashed line, closer to horizon for lower altitudes - sensitive to fore-aft (rotational) and altitude disturbances 3. *Optical splay angle*: more spread out at lower altitudes (hard to explain, see 1/17 packet for visual expl.n) - sensitive to lateral and altitude disturbances

What is Schmidt's Law? What are the IVs and DVs?

• We = a + b(A/MT) • Independent Variables - A = movement distance - MT = movement time goal set by expr - A/MT = Average movement velocity • Dependent variable - We = Effective target width = standard deviation of movement endpoints

What coordination structures are seen in golfers of different ages?

• Younger golfers primarily use 2 coordinative units in parallel • Older golfers have greater use of 1 integrated coordinative unit

What were the findings from putting a midbrain cat on a treadmill? What does this imply about coordination of gait transitions?

• possible to get gait transitions (walk -> trot -> gallop) just by speeding up the treadmill • implies cortex not important in coordinating gait transitions - suspicion is that the spinal cord is responsible for generating these patterns -- one working hypothesis

What transition is seen in bimanual finger oscillations across speeds?

• sudden transition from anti-phase to in-phase at high rates