Oculomotor System within human central system

Describes the Oculomotor system. It is a system specifically designed to control the varous eye movements.

1. Oculomotor System

2. What is the Oculomotor system
•Definition. The oculomotor system consists
of interconnected regions throughout the
central nervous system that interact to
control various eye movements. It includes
different brainstem nuclei, the superior
colliculus of the midbrain, and various
regions throughout the cerebral cortex

3. Oculomotor Nerve
•the third cranial nerve, which contains both
motor and sensory fibers and innervates
most of the muscles associated with
movement and accommodation of the eye
and constriction of the pupil (i.e., all the
muscles of the eye except the external
rectus and superior oblique muscles). Also
called cranial nerve III. (APA Directory )

4. What is the oculomotor nerve?
•The oculomotor nerve is one of 12 sets of
cranial nerves. Many of these nerves are part of
the autonomic nervous system. The autonomic
nervous system supplies (innervates) organs,
like your eyes
•The oculomotor nerve is the third cranial nerve
(CN III). It allows movement of the eye
muscles, constriction of the pupil, focusing the
eyes and the position of the upper eyelid.

5. •Cranial nerve III works with other cranial nerves
to control eye movements and support sensory
functioning.
i.Olfactory nerve (CN I) enables sense of smell.
ii.Optic nerve (CN II) enables vision.
iii.Trigeminal nerve (CN V) enables sensation in
your face.
iv.Vestibular and cochlear nerves (CN VII) enable
balance and hearing.

6. What is the function of the
oculomotor nerve?
•It controls four of the six muscles that enable
eye movement. CN III makes it possible to:
i.Elevate the upper eyelid.
ii.Focus the eyes.
iii.Respond to light by making the black center of
the eye (pupil) smaller.
iv.Move your eyes inward, outward, up and down
and control torsion.

7. How does CN III work?
•It coordinates eye movement with motions
that include:
i.Accommodation, focusing on an object
that’s moving closer to or further away from
you.
ii.Optokinetic reflex, changing eyes back to
their previous position after focusing on an
object.

8. i.Saccades, quick motions that shift your gaze
from one object to another.
ii.Smooth pursuit (visual tracking), which
enables you to hold your gaze on a moving
object.
iii.Vestibule-ocular reflex, which adjusts eye
positioning when your head is moving.
iv.Visual fixation, gazing at an object that is not
moving.

10. Oculomotor system and the
effluence of Emotions

11. Types of Eye Movements and
Their Functions
•There are four basic types of eye movements:
i. saccades, (Ballistic, conjugate eye
movements that change the point of foveal
fixation.)
ii.smooth pursuit movements

12. iii. Vergence movements (disjunctive
movements of the eyes (convergence or
divergence) that align the fovea of each eye
with targets located at different distances from
the observer)
iv. vestibulo-ocular movements

13. saccades,
•Saccades are rapid, ballistic movements of the
eyes that abruptly change the point of fixation.
They range in amplitude from the small
movements made while reading, for example,
to the much larger movements made while
gazing around a room. Saccades can be elicited
voluntarily, but occur reflexively whenever the
eyes are open, even when fixated on a target

14. Smooth pursuit movements
•are much slower tracking movements of the
eyes designed to keep a moving stimulus on
the fovea. Such movements are under
voluntary control in the sense that the
observer can choose whether or not to track
a moving stimulus

15. Eye Emotional responses lets
discuss

16. Researches on the Oculomoter
emotional responses
•Eye movement related brain responses to
emotional scenes during free viewing Jaana
Simola*, Jari Torniainen, Mona Moisala,
Markus Kivikangas and Christina M.
Krause (Cognitive Science/Cognitive Brain
Research Unit, Institute of Behavioural
Sciences, University of Helsinki, Helsinki,
Finland

17. •study investigated attention and emotion processes by measuring brain
responses related to eye movement events while 11 participants viewed
images selected from the International Affective Picture System (IAPS).
Brain responses to emotional stimuli were compared between serial and
parallel presentation. An “emotional” set included one image with high
positive or negative valence among neutral images. A “neutral” set
comprised four neutral images. The participants were asked to indicate
which picture—if any—was emotional and to rate that picture on valence
and arousal. In the serial condition, the event-related potentials (ERPs)
were time-locked to the stimulus onset. In the parallel condition, the
ERPs were time-locked to the first eye entry on an image. The eye
movement results showed facilitated processing of emotional, especially
unpleasant information. The EEG results in both presentation conditions
showed that the LPP (“late positive potential”) amplitudes at 400–500 ms
were enlarged for the unpleasant and pleasant pictures as compared to
neutral pictures.

18. •Moreover, the unpleasant scenes elicited stronger responses
than pleasant scenes. The ERP results did not support
parafoveal emotional processing, although the eye
movement results suggested faster attention capture by
emotional stimuli. findings, thus, suggested that emotional
processing depends on overt attentional resources engaged in
the processing of emotional content. The results also indicate
that brain responses to emotional images can be analyzed
time-locked to eye movement events, although the response
amplitudes were larger during serial presentation.

19. Covert attention and eye
movements
•Spatial attention can be allocated to a
stimulus with or without eye movements.
When attention is shifted to a location
without eye movements, we speak of covert
attention. When attention is shifted to a
location with eye movements, we speak of
overt attention (Posner, 1980).

20. •Behavioral studies on covert attention with manual
responses have shown inconsistent results regarding
the ability of emotional stimuli to capture attention
in healthy populations (see for reviews Bar-Haim et
al., 2007; Yiend, 2010).
• Specifically, early attention effects such as
enhanced attentional capture are not always found in
covert attention studies with manual responses (e.g.,
Koster, Crombez, Van Damme, Verschuere & De
Houwer, 2004; Notebaert, Crombez, De Houwer, &
Theeuwes, 2011; Mulckhuyse & Crombez, 2014).

21. Reference
•Becker, Hoehne, Iwase, & Kornhuber,
1972; Everling, Krappmann, & Flohr, 1997;
Moster & Goldberg, 1990; Thickbroom &
Mastaglia, 1985)