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Oculomotor system II. VOR (vestibulo-ocular reflex)
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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 II.VOR (vestibulo-ocular reflex)
Properties of MotoneuronsFi
ring
Freq
uenc
y
Eye Position (E)
Firin
g Fr
eque
ncy
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 +
Vestibulo-ocular Reflex
Vestibulo-Ocular Reflex
CNS
H E
H (-1) = E
Semicircular canals3 semicircular canals (horizontal, anterior, posterior) on each side of headThe canals are orthogonal to each other to represent complete 3-d rotations
Vestibulo-ocular Reflex
Hea
d m
o tio
n
nose
LR
MR
LR
MR
Horizontal canal
VestibularNucleus
AbducensNucleus
OculomotorNucleus
LR = lateral rectusMR = medial rectus
midline
(midbrain) (pons) (pons-medulla)
Horizontal VOR
Vestibular hair cell and afferent response
Hair cell (generator potential)
Primary vestibular afferent(action potentials to cns via 8th nerve)
Opponent processing: afferent has resting discharge and can therefore signal both directions of head motion via increase or decrease in activity
Hea
d m
o tio
n
nose
LR
MR
LR
MR
Horizontal canal
VestibularNucleus
AbducensNucleus
OculomotorNucleus
LR = lateral rectusMR = medial rectus
midline
(midbrain) (pons) (pons-medulla)
(-)
Horizontal VOR
Hea
d m
o tio
n
nose
LR
MR
LR
MR
Horizontal canal
VestibularNucleus
AbducensNucleus
OculomotorNucleus
LR = lateral rectusMR = medial rectus
midline
(midbrain) (pons) (pons-medulla)
Horizontal VOR
Hea
d m
o tio
n
nose
LR
MR
LR
MR
Horizontal canal
VestibularNucleus
AbducensNucleus
OculomotorNucleus
LR = lateral rectusMR = medial rectus
midline
(midbrain) (pons) (pons-medulla)
Horizontal VOR
Vestibulo-ocular Reflex
Canals organized into 3 orthogonal planes
Muscles organized into 3 orthogonal pairs
3-D organization of VOR