Eye movements, visual attention and reading

Question 1

what is the superior colliculus

Answer 1

A multi-layered structure that transforms sensory inputs into commands for directional movements.
It communicates with other regions of the brain involved in higher functions

Question 2

what is the reticular formation

Answer 2

a collection of neurons that is involved in many processes such as sleep, muscle tone or coordination of breathing

Question 3

what are conjugate eye movements and what muscles are used

Answer 3

movement of both eyes in the same direction to maintain binocular gaze.
lateral and medial rectus

Question 4

what are the agonist muscles and antagonist muscles when looking to the right

Answer 4

agonist - right lateral rectus and left medial rectus

antagonist - right medial rectus and left lateral rectus

Question 5

conjugate eye movements can be explained by which two laws

Answer 5

Herings law - states that innervation to the extraocular muscles is equal to both eyes. movement of two eyes are equal and symmetrical. (agonist muscles receive equal amounts of innervation so both eyes moved in same direction and same force)

Sherrington’s law - contraction of a muscle is accompanied by simultaneous and proportional relaxation of its antagonist muscles (antagonist muscles receive equal amounts of nerve signals to ensure they relax by the same amount to allow the eye movement to happen)

Question 6

What cranial nerve goes with what muscles

Answer 6

lateral rectus - cranial nerve 6 (abducens)
SO - cranial nerve 4 (trochlear)
medial rectus and all others - cranial nerve 3 (oculomotor nerve)

Question 7

what are all the types of conjugate eye movements and all the disjunctive eye movements

Answer 7

• Gaze stabilizing –> Vestibulo-ocular reflex and opto-kinetic reflex
• Gaze holding - slow –> fixation and pursuit
• Gaze holding - fast –> saccade

Disjunctive:
- Gaze shifting and holding in-depth, slow –> vergence and versions

Question 8

what is Vestibulo-ocular reflex

Answer 8

• Gaze stabilising reflex
• the eyes move in the opposite direction to the head rotation
• effective for fast head movements

Question 9

what is optokinetic reflex

Answer 9

• Gaze stabilising reflex
• Head stays in one position and eyes move with the surroundings then flip back and move again.
• effective for slow movements

Question 10

what is fixation

Answer 10

actively engaging in looking at an image of choice. a variety of small eye movements - the eye does not remain still

Question 11

what is a pursuit

Answer 11

follows a slowly moving target.

Question 12

what is a saccade

Answer 12

shift fixation from one target to another

Question 13

what are version eye movements

Answer 13

movements of two eyes in the same direction

Question 14

vergence eye movements

Answer 14

eyes moving in the opposite direction

Question 15

what are the three types of movements during fixation

Answer 15

tremors - aka physiological nystagmus, small movements at high frequencies

drifts - arcuate movements, low-frequency small movements but larger than tremors

microsaccades - sudden relocations, small fast movements

Question 16

what 3 types of visual attention are there

Answer 16

spatial attention - where
temporal attention - when
object attention - what

Question 17

what is the Troxler effect

Answer 17

the fading of a stable image on the retina

Question 18

yoked muscles are responsible for which type of eye movement

Answer 18

versions - the eyes move in the same direction

Question 19

what does salience mean

Answer 19

the ease with which an object or feature attracts our visual attention

Question 20

if the spotlight of visual attention tracks multiple objects how does this affect performance

Answer 20

error rate and response are both affected

Question 21

what was posners cuing trials

Answer 21

• A spatial attention utilised
• A target is presented after a time interval, cue or uncued
  -The task is to indicate the target location as quickly as possible

Question 22

what drives visual attention

Answer 22

knowledge driven - voluntary, overt control, slower response over time as it is a sustained response. essential to survive

stimulus driven - in an object or scene some element will catch our eye or pop out and will not require previous decision or knowledge to attend to it. Rapid and automatic

Question 23

what is the Gilchrist model for reading

Answer 23

select - reader selects and fixes on a word
decode - decoded to see whether it can be recognised as meaningful
refixate - saccadic eye movements bring about a change in fixation to select the next group of interest

Question 24

what are the three types of reading tests

Answer 24

1) international reading speed test (IREST) paragraph
2) Wilkins rate of reading test (WWRT) paragraph
3) Test of word reading efficiency (TOWRE) columns

Question 25

what do the reading tests measure

Answer 25

accuracy and rate