Oc Motility Final

Front 1

Saccadic eye movement allows for? relative eye speed versus others?

Back 1

rapid change of eye position. fastest in terms of speed, eye movement.

Front 2

Classifications of saccades

Back 2

1. volitional saccades, voluntary saccades.
2. reflexive saccades
3. Spontaneous saccades
4. Quick phase of nystagmus
5. rapid eye movement sleep

Front 3

Overview of saccades generation

Back 3

Cortex - command to make saccade
Brainstem - generates pulse and steps signals
EOMS - make the actual movement

Front 4

Main sequence is the ____ portion of the data/curve

Back 4

linear portion

Front 5

velocity amplitude relationship

Back 5

saccadic speed must be faster with longer duration

Front 6

Duration amplitude relationship

Back 6

larger saccades require more time.

Front 7

Static hypometria

Back 7

step size error, static undershoot, corrected by a corrective saccade, occurs more in periphery.

Front 8

Static hypermetria

Back 8

step size error, signal is too large, static overshoot. occurs more often in central.

Front 9

glassadic hypometria

Back 9

error in pulse signal, glassadic undershoot, corrected by glissade

Front 10

glassadic hypermetria

Back 10

error in pulse signal, glassadic overshoot, corrected by glissade.

Front 11

Combined dysmetria

Back 11

pulse and step problem

Front 12

If step size error then corrected by a?

Back 12

corrective saccade

Front 13

If pulse size error then corrected by a?

Back 13

Glassadie

Front 14

Sampled data model

Back 14

Once programmed saccade, saccade cannot be modified

Front 15

Continuous sampling model

Back 15

saccade can be modified up to 70 msec before saccade occurs.

Front 16

Saccadic omission

Back 16

intervention to prevent blurring of vision during a saccade

Front 17

Saccadic suppression

Back 17

reduction in visual sensitivity during saccadic eye movement.

Front 18

Saccadic masking

Back 18

reduction in ability to detect blur during saccadic eye movements.

Front 19

Higher visual levels of saccades include?

Back 19

frontal cortex, parietal cortex, thalamus, superior colliculus and basal ganglia.

Front 20

Premotor neurons generate?

Back 20

pulse and step.
From burst neurons 2 classes
excitatory burst neurons, generate pulse signal.
inhibitory burst neurons, inhibit antagonist EOMs.

Front 21

excitatory burst neurons for horizontal saccades are located in the?

Back 21

PPRF, paramedian pontine reticular formation

Front 22

inhibitory burst neurons for horizontal saccades are located in the?

Back 22

rostral medulla

Front 23

Burst neurons for vertical and torsional saccades are in the

Back 23

riMLF,

Front 24

Tonic neurons for horizontal saccades

Back 24

carry the step signal, and are the neural integrates which integrate burst signals to step signals. Nucleus prepositus hypoglossi (NPH) and medial vestibular nucleus (MVN).

Front 25

Tonic neurons for vertical or torsional saccades

Back 25

INC or interstitial nucleus of cajal, integrates burst signal from excitatory burst neurons in the riMLF to step signals.

Front 26

Pause neurons

Back 26

discharge in the absence of saccades but stop discharging before and during saccades. pause to allow saccades to occur. Also stop firing during blinks. located in the nucleus raphe interpositus.

Front 27

Cerebellum plays a role in saccades?

Back 27

control of saccadic accuracy.
Dorsal vermis and fastigial nucleus - saccadic amplitude.
flocculus calibrates the saccadic pulse-step match.

Front 28

Pursuits are generated to? And are evolved from?

Back 28

follow or track a moving target. evolved from OKN.

Front 29

Pursuit latency

Back 29

100-150 msec

Front 30

OKN latency

Back 30

70 msec

Front 31

VOR latency

Back 31

16 msec

Front 32

Saccadic latency

Back 32

200 msec

Front 33

Ramp target stimulus of pursuits?

Back 33

100 msec latency, as eye begins to move there is a pursuit that lags behind and is corrected by a catch up saccade. The pursuit then become accurate.

Front 34

Step-ramp target stimulus of pursuits?

Back 34

150 msec latency, as eye begins to move there is a pursuit that becomes increasingly accurate as the target and eye movments coincide.

Front 35

Initial stage of pursuits are considered?

Back 35

open loop, first 100 msec of pursuits, does not recieve feedback to modify its performance, this is the intrinsic property of the pursuit system.

Front 36

2nd stage of pursuits are considered?

Back 36

closed loop, remainder of pursuits, able to receive feedback and modify its performance.

Front 37

Pursuit gain, up to 40 deg/sec

Back 37

nice and smooth

Front 38

pursuit gain, 40-100 deg/sec

Back 38

saccadic intrusion, target moving too fast or in unpredictable path.

Front 39

Pursuit gain, above 100 deg/sec

Back 39

jerky saccadic pursuit

Front 40

Neurophysiology of pursuits

Back 40

retina -> LGN ->(motion info) Middle temporal, Medial superior temporal, and posterior parietal -> Dorsolateral pontine nuclei, accesory optic system, nucleus of optic tract, cerebellum, flocculus and dorsal vermis synthesis pursuit signal -> neural integrators -> final pathways.

Front 41

Lesions on horizontal pursuits, Primary visual cortex

Back 41

Contralateral field defect, no vision or pursuit occurs

Front 42

Lesions on horizontal pursuits, Middle temporal

Back 42

contralateral field, does not see or percieve motion well.

Front 43

lesions on horizontal pursuits, medial superior temporal

Back 43

impairs pursuits for targets moving toward size of lesion, ipsilateral.

Front 44

lesions on horizontal pursuits, posterior parietal

Back 44

contralateral inattention

Front 45

lesions on horizontal pursuits, frontal eye frield

Back 45

ipsilateral defect

Front 46

lesions on horizontal pursuits, dorsolateral pontine nucleus

Back 46

ipsilateral defect

Front 47

lesions on horizontal pursuits, cerebellum

Back 47

ipsilateral defect.

Front 48

Center for horizontal conjugate eye movements is?

Back 48

abducens nucleus. recieves information from PPRF (excitatory burst neurons), NPH, MVN (step signal) and sends information via MLF to contralateral ocularmotor nucleus.

Front 49

ultimate cerebellum ensure that?

Back 49

all classes of eye movement are calibrated.