國立虎尾科技大學 |

Computational analysis of pattern generation in reduced vertebrate motor circuit models.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Computational analysis of pattern generation in reduced vertebrate motor circuit models./
Author:	Snyder, Abigail.
Description:	1 online resource (157 pages)
Notes:	Source: Dissertation Abstracts International, Volume: 78-05(E), Section: B.
Contained By:	Dissertation Abstracts International78-05B(E).
Subject:	Applied mathematics. -
Online resource:	click for full text (PQDT)
ISBN:	9781369418675

Computational analysis of pattern generation in reduced vertebrate motor circuit models.
Snyder, Abigail.

Computational analysis of pattern generation in reduced vertebrate motor circuit models. - 1 online resource (157 pages)

Source: Dissertation Abstracts International, Volume: 78-05(E), Section: B.

Thesis (Ph.D.)

Includes bibliographical references

Rhythmic behaviors such as breathing, walking, and scratching are vital to many species. Such behaviors can emerge from groups of neurons, called central pattern generators (CPGs), in the absence of rhythmic inputs. In vertebrates, the identification of the cells that constitute the CPG for particular rhythmic behaviors is difficult, and often, its existence has only been inferred. In the second and third chapters of this thesis, we use two reduced mathematical models to investigate the capability of a proposed network to generate multiple scratch rhythms observed in turtles. Under experimental conditions, intact turtles generate several rhythmic scratch motor patterns corresponding to non-rhythmic stimulation of different body regions. These patterns feature alternating phases of motoneuron activation that occur repeatedly, with different patterns distinguished by the relative timing and duration of activity of hip extensor, hip flexor, and knee extensor motoneurons. We show through simulation that the proposed network can achieve the desired multi-functionality, even though it relies on hip unit generators to recruit appropriately timed knee extensor motoneuron activity. We develop a phase space representation which we use to derive sufficient conditions for the network to realize each rhythm and which illustrates the role of a saddle-node bifurcation in achieving the knee extensor delay. This framework is harnessed to consider bistability and to make predictions about the responses of the scratch rhythms to input changes for future experimental testing. We also consider a stochastic spiking model to reproduce firing rate changes observed in experiment, explore the relative contributions of different parameters in the model to the observed changes, support our collaborators' hypothesis regarding these changes, and provide our collaborators with predictions for future experiments. In the fourth chapter of this thesis, we present a theoretical study examining whether three mechanisms suggested by deletion experiments can operate in the same CPG for an extensor-flexor pair in the mammalian central nervous system during locomotion. We arrive at unique solution properties produced by each of the three mechanisms for use in future experiments. Our findings propose explanations for the coexistence of the three experimentally suggested yet seemingly contradictory mechanisms for rhythmogenesis.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9781369418675Subjects--Topical Terms:

1069907
Applied mathematics.
Index Terms--Genre/Form:

554714
Electronic books.

Computational analysis of pattern generation in reduced vertebrate motor circuit models.
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100 1 $a Snyder, Abigail. $3 1180788
245 1 0 $a Computational analysis of pattern generation in reduced vertebrate motor circuit models.
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300 $a 1 online resource (157 pages)
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500 $a Source: Dissertation Abstracts International, Volume: 78-05(E), Section: B.
500 $a Adviser: Jonathan E. Rubin.
502 $a Thesis (Ph.D.) $c University of Pittsburgh $d 2016.
504 $a Includes bibliographical references
520 $a Rhythmic behaviors such as breathing, walking, and scratching are vital to many species. Such behaviors can emerge from groups of neurons, called central pattern generators (CPGs), in the absence of rhythmic inputs. In vertebrates, the identification of the cells that constitute the CPG for particular rhythmic behaviors is difficult, and often, its existence has only been inferred. In the second and third chapters of this thesis, we use two reduced mathematical models to investigate the capability of a proposed network to generate multiple scratch rhythms observed in turtles. Under experimental conditions, intact turtles generate several rhythmic scratch motor patterns corresponding to non-rhythmic stimulation of different body regions. These patterns feature alternating phases of motoneuron activation that occur repeatedly, with different patterns distinguished by the relative timing and duration of activity of hip extensor, hip flexor, and knee extensor motoneurons. We show through simulation that the proposed network can achieve the desired multi-functionality, even though it relies on hip unit generators to recruit appropriately timed knee extensor motoneuron activity. We develop a phase space representation which we use to derive sufficient conditions for the network to realize each rhythm and which illustrates the role of a saddle-node bifurcation in achieving the knee extensor delay. This framework is harnessed to consider bistability and to make predictions about the responses of the scratch rhythms to input changes for future experimental testing. We also consider a stochastic spiking model to reproduce firing rate changes observed in experiment, explore the relative contributions of different parameters in the model to the observed changes, support our collaborators' hypothesis regarding these changes, and provide our collaborators with predictions for future experiments. In the fourth chapter of this thesis, we present a theoretical study examining whether three mechanisms suggested by deletion experiments can operate in the same CPG for an extensor-flexor pair in the mammalian central nervous system during locomotion. We arrive at unique solution properties produced by each of the three mechanisms for use in future experiments. Our findings propose explanations for the coexistence of the three experimentally suggested yet seemingly contradictory mechanisms for rhythmogenesis.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Applied mathematics. $3 1069907
650 4 $a Mathematics. $3 527692
655 7 $a Electronic books. $2 local $3 554714
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710 2 $a University of Pittsburgh. $3 1178873
773 0 $t Dissertation Abstracts International $g 78-05B(E).
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