Doctoral theses
Current Record: 2066 of 2438
|
Identifier |
000365658 |
Title |
Principles of eye-head coordination |
Alternative Title |
Αρχές συντεταγμένης κίνησης οφθαλμού-κεφαλής |
Author
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Καρδαμάκης, Αντώνης-Ανδρέας
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Thesis advisor
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Μοσχοβάκης, Α
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Reviewer
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Αργυρός, Α
Τσακίρης, Δ
Αναστασόπουλος, Δ
Σαββάκη, Ε
Χριστάκος, Κ
Αθανασίου, Γ
|
Abstract |
To explore the visible world, humans and other animals rapidly shift their line of sight to potential
targets. These voluntary movements are executed by the eyes either alone, in which case they
are called saccades, or in coordination with the head in which case they are called gaze shifts.
Both of these movements serve the same goal reliably, accurately and fast while displaying highly
stereotypical metrics and kinematics during movement execution. The strategy and mechanisms that
are employed by the nervous system when planning gaze shifts are gleaned from two computational
models that were formulated in this thesis and address the phenomenon of eyehead
coordination
at two different levels of abstraction.The first model used optimal control theory to discover the
crucial variables and constraints that are important during motor planning of gaze shifts. This model
accounts for the stereotypy that is observed in the psychophysics of headfixed
saccades and headfree
gaze shifts. Results from these simulations suggest that the organization principle that guides these
movements exploits a balance between effort and movement duration, thus implying that extraocular
muscle tension and energy dissipation due to inertial effects of the head and movement duration
are parameters that are collectively taken into consideration and minimized at the neural level. The
second computational model simulates the neural circuitry that generates eyehead
gaze shifts. The
goal of these neural network simulations is to model the relevant neural processes starting from
the spatial representation of the target (a neural map found in the superior colliculus) and ending
with the set of requisite neuromuscular commands that drive the eyes and head. A controltheoretic
systems approach is used to explore the computational repertory of the connectivity established by
the model units and to explore if it generates results consistent with the experimental data obtained
from neurophysiology, electrical stimulations, neuroanatomy, neurology and psychophysics. We
conclude that minimumeffort
is the movement organization principle of eyehead
coordination which
is implemented by the brain using a crosstalk mechanism between independently controlled head
and eye motor pattern generators.
vii
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Language |
Greek |
Subject |
Computational neuroscience |
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Motor control |
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Saccades |
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Κινητικός έλεγχος |
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Σακκάδικες |
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Υπολογιστικές νευροεπιστήμες |
Issue date |
2006-03-22 |
Collection
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School/Department--School of Medicine--Department of Medicine--Doctoral theses
|
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Type of Work--Doctoral theses
|
Permanent Link |
https://elocus.lib.uoc.gr//dlib/b/f/1/metadata-dlib-cc11f46c80570b9c168fe30ad99ea9c2_1304666315.tkl
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Views |
306 |