nsci 324* systems neuroscience
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NSCI 324* Systems Neuroscience. Doug Munoz Centre for Neuroscience Studies Botterell Hall, room 226 x32111 [email protected] Tutorial: Monday Jan 23, 2012 10:30am Botterell B147 TA: Jay Jantz ([email protected]). NSCI 324* Systems Neuroscience. - PowerPoint PPT PresentationTRANSCRIPT
NSCI 324*Systems Neuroscience
Doug MunozCentre for Neuroscience StudiesBotterell Hall, room [email protected]
Tutorial: Monday Jan 23, 2012 10:30amBotterell B147TA: Jay Jantz ([email protected])
NSCI 324*Systems Neuroscience
Vision and Oculomotor Control (Dr. Munoz)January 10 The retina January 13 Central Visual PathwaysJanuary 16 Dr. Munoz Tutorial: January 16 Higher Visual functions January 17 Oculomotor System I. Basic organization January 20 Oculomotor System II. Vestibulo-ocular reflexJanuary 23 Dr. Munoz tutorial:January 23 Oculomotor System III. SaccadesJanuary 24 Basal Ganglia for cognitive and motor controlJanuary 27 review of Dr. Munoz lecture materialJanuary 30 Dr. Munoz exam in tutorial period
Oculomotor system I.Basics
Movements that stabilize the eye when the head moves
Movements that align the fovea with a visual target
Movements that stabilize the eye when the head moves
Movements that align the fovea with a visual target
Vestibulo-ocular
Vestibulo-ocular Reflex
Movements that stabilize the eye when the head moves
Movements that align the fovea with a visual target
Vestibulo-ocular
Optokinetic
Movements that stabilize the eye when the head moves
Movements that align the fovea with a visual target
Vestibulo-ocular
Optokinetic
Saccade
Visual Fixation
Saccades allow us to scan the visual field and intermittently focus our attention on the parts of the scene that convey the most significant
information.
Saccade-Fixation Behaviour
Eye movements reveal a good deal about the strategies used to inspect a visual scene. Each scan reflects the current task.
Free examination
An Unexpected Visitor (I.E. Repin)
Gaze position
What do Saccades Accomplish?
Instruction: “Give the ages of the people.”
An Unexpected Visitor (I.E. Repin)
What do Saccades Accomplish?
Instruction: “Remember the clothes worn by the people.”
An Unexpected Visitor (I.E. Repin)
What do Saccades Accomplish?
Instructions: “Remember the position of the people and the objects in the room.”
An Unexpected Visitor (I.E. Repin)
What do Saccades Accomplish?
Instruction: “Estimate how long the unexpected visitor had been away from the family.”
An Unexpected Visitor (I.E. Repin)
What do Saccades Accomplish?
The human eyes voluntarily and involuntarily fixate on those elements of a visual scene that carry essential and useful information. The more
information is contained in an element, the longer the eyes stay on it.
The distribution of fixations on the elements of a scene changes depends on the purpose of the observer, i.e., it is determined by information to be
obtained and the thought process accompanying the analysis of this information.
Hence people who think differently also, to some extent, see differently.A.L. Yarbus (1967)
What do Saccades Accomplish?
Movements that stabilize the eye when the head moves
Movements that align the fovea with a visual target
Vestibulo-ocular
Optokinetic
Saccade
Visual Fixation
Smooth Pursuit
Movements that stabilize the eye when the head moves
Movements that align the fovea with a visual target
Vestibulo-ocular
Optokinetic
Saccade
Visual Fixation
Smooth Pursuit
Vergence
Vergence
Fixate far target Fixate near targetVergence: eyes move in opposite directionsConvergence: to fixate near objectsDivergence to fixate far objects
Retinal Disparity Drives Vergence Eye Movements
Retinal disparity: difference in location of image between the two eyes. Disparity signal is derived in extrastriate cortex (dorsal stream)
Extraocular Muscles
Extraocular Muscles
Extraocular Muscle Innervation
The Oculomotor and Trochlear
nerves originate from the midbrain.
The Abducens nerve originates from the pons.
Lateral view
Discharge Properties of Motoneurons
Properties of MotoneuronsF
iring
Fre
quen
cy
Eye Position (E)
Firi
ng F
requ
ency
Eye Velocity (E)
Extraocular Muscle Motoneurons
carry eye position and eye velocity
final common path for all eye movements
integrator located in reticular formation and vestibular complex of brainstem part of final common path
“Neural integrator” integrates E command to produce E command
muscleMNE + E
E
+
E +