E y e Mo v em ent s (C ha pt er 8 ) a nd T he V es t ibul a r S y s t em (C ha pt er 1 2)
T wo B ig V is ua l Pr o c es s ing S t r ea m s : W ha t v s . W her e
• The Pa r v o - Ma g no s y s t em splits into:
o V entral stream ("What" pathway): Helps us recognize objects, form, and color. Goes towards
the t em po r a l l o be.
o D o rsal stream ("Where/ Ho w" pa t hwa y ) : Helps us understand motion, where things are in
space, and guides action. Goes towards the pa r iet a l l o be.
Example: Ventral = Recognizing a face. Dorsal = Reaching out to grab a cup.
Motion tells us how objects are in relation to us
W hy E y e Mo v em ent s Ma t t er
• The do r s a l s t r ea m tells us where things are and how they move. But:
o O ur eyes move, so we need to k no w where we are looking to understand where things are in
space.
o To track how things move, we also need to k no w ho w o ur hea d a nd ey es a r e m o v ing .
🎯 E y e Mo v em ent s Fo l l o w A t t ent io n
• T o o m uc h info comes into our eyes to process all at once.
• We focus attention on o ne part o f t he s c ene, and often m o v e o ur ey es to that place—this is called
o v er t a t t ent io n.
• Eyes jum p in small movements called s a c c a des , between fix a t io ns where we focus on one spot.
💡 Fix a t io ns a nd A t t ent io n
• We fix a t e on im po r t a nt pa r t s of what we look at.
• Our vision is s har pes t a t t he fo v ea , the center of gaze, which is why fix a t io ns help us see details.
E y e movement allows to s ee important parts of an image in detail bc our vision is the best at fixation (wher e
a r e we l o o k ing )
E y e Mo v em ent s in t he B r a in: Refl ex iv e a nd V o l unt a r y
1. Refl ex iv e (E x o g eno us ) :
, a. Attention and eye movements a utomatically go toward sudden events (like flashes or noises).
b. Controlled by the s uper io r c o l l ic ul us , which is a brain structure important for quic k ,
a ut o m a t ic ey e m o v em ent s .
i. Upper l a y er s : Process s ens o r y input (vision + sound). Spatial receptive fields for
auditory and visual information
ii. Middl e l a y er s : Generate m o t o r commands for eye movements.
2. Ho w It W o r k s :
a. A stimulus (flash, noise) is detected → processed in the upper l a y er s → sent to the m iddl e
l a y er s , which m o v e t he ey es toward it.
b. The s uperior colliculus motor map controls how big the eye movement is and where to move,
based on r et ino t o pic c o o r dina t es (relative to where the eyes are already looking).
✋ T o uc h a nd E y e Mo v em ent s
• We can also m o v e o ur ey es to where we feel something on our body. Again, an exogenous driven
movement.
• This involves:
o The po s t er io r pa r iet a l c o r t ex : Converts touch into a visual target.
o Then signals the s uper io r c o l l ic ul us to move the eyes toward that spot.
🧭 V o l unt a r y (E ndo g eno us ) E y e Mo v em ent s
• These are g o al-dr iv en—not triggered by external stimuli. We make eye movement in very voluntary
ways – when eye movements follow endogenous attention, the attention control system of the
parietal and frontal areas are really important, and they eventually interact with the frontal eye fields
(allows the brain to figure out which movement to make to reach the goal and the frontal eye field s
then give their input where we make the eyemovementnt.
• When eye-movement is completely voluntary (look up for no reason, there is nothing there) the
supplementary eye fields become activate
• Involve:
o Pa r iet a l l o be a t t ent io n s y s t em s : Control voluntary attention.
o Fr ontal Eye Fields (FE F) : Coordinate voluntary eye movements, part of pr em o t o r c o r t ex
(which plans actions, we make movements to interact with things).
o S upplementary Eye Fields (S E F) : Handle completely internal movements with no particular
goal – no input (deciding to look somewhere even if there’s no external reason).
Example: If I ask you to "look up" without anything drawing your attention, you use these areas.
• Regardless of how the movement starts (reflexive or voluntary), final eye movement commands pass
through the s uper io r c o l l ic ul us .
🎡 V es t ibul a r S y s t em C o nnec t io n (C ha pt er 1 2)
• Not covered in your notes here, but important:
o The v es t ibul a r s y s t em tells your brain about hea d m o v em ent and ba l a nc e.
o It works with the v isua l s y s t em to keep your eyes stable when you move your head. This is
part of the v es t ibul o - o c ul a r r efl ex (V O R) : when your head moves one way, your eyes
automatically move the other to keep your gaze steady.
,🧩 Put t ing It A l l T o g et her
• To per c eiv e where things are and how they move, your brain combines:
o Info about ey e po s it io n (where you’re looking).
o Info about hea d m o v em ent (vestibular system).
o The m o t io n and l o c a t io n of objects in space (dorsal stream).
• This integration helps with s pa t ia l a wa r enes s , c o o r dina t io n, and int er a c t ing with the world.
superior colliculus’s activity sets the end position of the saccade. But the eyes are moved by a specific set of
muscles. We need to activate the muscles The oculomotor nucleus, together with the abducens nucleus and
trochlear nucleus, converts the end location of the saccade to the muscle movements required to reach that
goal
If we want to make an eye movement – we need to know how to convert the location we want to make the eye
movement to in a set of muscle movement
Ho w E y e Mo v em ent s A r e C o nt r o l l ed - S a c c a des (Q uic k Jum ps )
• W ha t a r e s a c c a des ?
Fast, jerky eye movements that quickly jump your gaze from one point to another (like when you
read or scan a room).
• Go a l o f s a c c a des :
Move your eyes to a new po s it io n so you can focus on something important.
➡️ Ho w t he B ra i n Pl a ns a nd E xe c ut e s a S a c c a de
• The s uper io r c o l l ic ul us decides wher e the eyes should end up. This is the g o a l l o c a t io n.
• But that’s just a pl a n—the ey e m us c l es need to know ho w t o m o v e to get there.
, ➡️ Mus c l e Co nt ro l :
• The o c ulomotor nucleus, abducens nucleus, and t rochlear nucleus in the brainstem t ransla t e the goal
(where the eyes should look) into actual m us c l e m o v em ent s . -they get input from the supperior
colliculus
o These nuclei c o nt r o l differ ent m us c l es attached to the eyeball.
o They make sure the eyes move precisely to the new position and stop there.
🎯 S m o o t h Pur s uit E y e Mo v em ent s (T r a c k ing a Mo v ing O bjec t )
• W ha t a r e s m o o t h pur s uit m o v em ent s ?
Slow, controlled eye movements that fo l low a mo v ing o bjec t smoothly (like following a flying bird
with your gaze). Strong exogenous aim to follow something
• Ho w a r e t hey differ ent fr o m s a c c a des ?
o S a c c a des = quick jumps to a new spot.
o S m o o t h pur s uit = slow tracking of something that’s already moving.
• D r iv en by :
External motion (ex ogenous control ). You follow the object’s movement, matching your eye speed to
it.
➡️ Pe rc e pt i o n Di ffe re nc e s :
• If you stare at a s t ationary dot, and something moves past it, your brain knows t he object is m o v ing .
W e perceive it as moving bc our eyes are stationary – r et ina l m o t io n c a us ing by o bjec t m o t io n
• But if you fo l low a moving object with your eyes, and the background (dot) moves across your retina
in the same way, your brain k no ws the dot isn’t mov ing , because y o u a r e m o v ing y o ur ey es . W e
per ceive it as stationary bc our eyes are moving - r et ina no t m o t io n c a us ing fr o m ey e m o v ent
W e need to have info about the eye movement in order to tell us how something wa s m o v ing o r no t in t he
wo r l d
T wo B ig V is ua l Pr o c es s ing S t r ea m s : W ha t v s . W her e
• The Pa r v o - Ma g no s y s t em splits into:
o V entral stream ("What" pathway): Helps us recognize objects, form, and color. Goes towards
the t em po r a l l o be.
o D o rsal stream ("Where/ Ho w" pa t hwa y ) : Helps us understand motion, where things are in
space, and guides action. Goes towards the pa r iet a l l o be.
Example: Ventral = Recognizing a face. Dorsal = Reaching out to grab a cup.
Motion tells us how objects are in relation to us
W hy E y e Mo v em ent s Ma t t er
• The do r s a l s t r ea m tells us where things are and how they move. But:
o O ur eyes move, so we need to k no w where we are looking to understand where things are in
space.
o To track how things move, we also need to k no w ho w o ur hea d a nd ey es a r e m o v ing .
🎯 E y e Mo v em ent s Fo l l o w A t t ent io n
• T o o m uc h info comes into our eyes to process all at once.
• We focus attention on o ne part o f t he s c ene, and often m o v e o ur ey es to that place—this is called
o v er t a t t ent io n.
• Eyes jum p in small movements called s a c c a des , between fix a t io ns where we focus on one spot.
💡 Fix a t io ns a nd A t t ent io n
• We fix a t e on im po r t a nt pa r t s of what we look at.
• Our vision is s har pes t a t t he fo v ea , the center of gaze, which is why fix a t io ns help us see details.
E y e movement allows to s ee important parts of an image in detail bc our vision is the best at fixation (wher e
a r e we l o o k ing )
E y e Mo v em ent s in t he B r a in: Refl ex iv e a nd V o l unt a r y
1. Refl ex iv e (E x o g eno us ) :
, a. Attention and eye movements a utomatically go toward sudden events (like flashes or noises).
b. Controlled by the s uper io r c o l l ic ul us , which is a brain structure important for quic k ,
a ut o m a t ic ey e m o v em ent s .
i. Upper l a y er s : Process s ens o r y input (vision + sound). Spatial receptive fields for
auditory and visual information
ii. Middl e l a y er s : Generate m o t o r commands for eye movements.
2. Ho w It W o r k s :
a. A stimulus (flash, noise) is detected → processed in the upper l a y er s → sent to the m iddl e
l a y er s , which m o v e t he ey es toward it.
b. The s uperior colliculus motor map controls how big the eye movement is and where to move,
based on r et ino t o pic c o o r dina t es (relative to where the eyes are already looking).
✋ T o uc h a nd E y e Mo v em ent s
• We can also m o v e o ur ey es to where we feel something on our body. Again, an exogenous driven
movement.
• This involves:
o The po s t er io r pa r iet a l c o r t ex : Converts touch into a visual target.
o Then signals the s uper io r c o l l ic ul us to move the eyes toward that spot.
🧭 V o l unt a r y (E ndo g eno us ) E y e Mo v em ent s
• These are g o al-dr iv en—not triggered by external stimuli. We make eye movement in very voluntary
ways – when eye movements follow endogenous attention, the attention control system of the
parietal and frontal areas are really important, and they eventually interact with the frontal eye fields
(allows the brain to figure out which movement to make to reach the goal and the frontal eye field s
then give their input where we make the eyemovementnt.
• When eye-movement is completely voluntary (look up for no reason, there is nothing there) the
supplementary eye fields become activate
• Involve:
o Pa r iet a l l o be a t t ent io n s y s t em s : Control voluntary attention.
o Fr ontal Eye Fields (FE F) : Coordinate voluntary eye movements, part of pr em o t o r c o r t ex
(which plans actions, we make movements to interact with things).
o S upplementary Eye Fields (S E F) : Handle completely internal movements with no particular
goal – no input (deciding to look somewhere even if there’s no external reason).
Example: If I ask you to "look up" without anything drawing your attention, you use these areas.
• Regardless of how the movement starts (reflexive or voluntary), final eye movement commands pass
through the s uper io r c o l l ic ul us .
🎡 V es t ibul a r S y s t em C o nnec t io n (C ha pt er 1 2)
• Not covered in your notes here, but important:
o The v es t ibul a r s y s t em tells your brain about hea d m o v em ent and ba l a nc e.
o It works with the v isua l s y s t em to keep your eyes stable when you move your head. This is
part of the v es t ibul o - o c ul a r r efl ex (V O R) : when your head moves one way, your eyes
automatically move the other to keep your gaze steady.
,🧩 Put t ing It A l l T o g et her
• To per c eiv e where things are and how they move, your brain combines:
o Info about ey e po s it io n (where you’re looking).
o Info about hea d m o v em ent (vestibular system).
o The m o t io n and l o c a t io n of objects in space (dorsal stream).
• This integration helps with s pa t ia l a wa r enes s , c o o r dina t io n, and int er a c t ing with the world.
superior colliculus’s activity sets the end position of the saccade. But the eyes are moved by a specific set of
muscles. We need to activate the muscles The oculomotor nucleus, together with the abducens nucleus and
trochlear nucleus, converts the end location of the saccade to the muscle movements required to reach that
goal
If we want to make an eye movement – we need to know how to convert the location we want to make the eye
movement to in a set of muscle movement
Ho w E y e Mo v em ent s A r e C o nt r o l l ed - S a c c a des (Q uic k Jum ps )
• W ha t a r e s a c c a des ?
Fast, jerky eye movements that quickly jump your gaze from one point to another (like when you
read or scan a room).
• Go a l o f s a c c a des :
Move your eyes to a new po s it io n so you can focus on something important.
➡️ Ho w t he B ra i n Pl a ns a nd E xe c ut e s a S a c c a de
• The s uper io r c o l l ic ul us decides wher e the eyes should end up. This is the g o a l l o c a t io n.
• But that’s just a pl a n—the ey e m us c l es need to know ho w t o m o v e to get there.
, ➡️ Mus c l e Co nt ro l :
• The o c ulomotor nucleus, abducens nucleus, and t rochlear nucleus in the brainstem t ransla t e the goal
(where the eyes should look) into actual m us c l e m o v em ent s . -they get input from the supperior
colliculus
o These nuclei c o nt r o l differ ent m us c l es attached to the eyeball.
o They make sure the eyes move precisely to the new position and stop there.
🎯 S m o o t h Pur s uit E y e Mo v em ent s (T r a c k ing a Mo v ing O bjec t )
• W ha t a r e s m o o t h pur s uit m o v em ent s ?
Slow, controlled eye movements that fo l low a mo v ing o bjec t smoothly (like following a flying bird
with your gaze). Strong exogenous aim to follow something
• Ho w a r e t hey differ ent fr o m s a c c a des ?
o S a c c a des = quick jumps to a new spot.
o S m o o t h pur s uit = slow tracking of something that’s already moving.
• D r iv en by :
External motion (ex ogenous control ). You follow the object’s movement, matching your eye speed to
it.
➡️ Pe rc e pt i o n Di ffe re nc e s :
• If you stare at a s t ationary dot, and something moves past it, your brain knows t he object is m o v ing .
W e perceive it as moving bc our eyes are stationary – r et ina l m o t io n c a us ing by o bjec t m o t io n
• But if you fo l low a moving object with your eyes, and the background (dot) moves across your retina
in the same way, your brain k no ws the dot isn’t mov ing , because y o u a r e m o v ing y o ur ey es . W e
per ceive it as stationary bc our eyes are moving - r et ina no t m o t io n c a us ing fr o m ey e m o v ent
W e need to have info about the eye movement in order to tell us how something wa s m o v ing o r no t in t he
wo r l d
