Maladaptive fear and L-type voltage gated calcium channel subtypes by Stephanie AJ Temme

281 Pages·2015·5.23 MB·English

Maladaptive fear and L-type voltage gated calcium channel subtypes
by
Stephanie A. J. Temme

A dissertation submitted in partial fulfillment
of the requirements for the degree of
Doctor of Philosophy
(Neuroscience)
in the University of Michigan
2015

Doctoral Committee:
Associate Professor Geoffrey G. Murphy, chair
Professor Lori L. Isom
Professor Audrey F. Seasholtz
Professor Edward L. Stuenkel
Associate Professor Michael M. A. Sutton
“it is a truth very certain that, when it is not in our power to determine the most true
opinions we ought to follow the most probable.”
― René Descartes
© Stephanie A. J. Temme 2015
Dedication
This thesis is dedicated to the two loves of my life:
To my loving husband Jacob, your love and support made it all possible
and
To my beautiful daughter Catalina, may you never lose your spark of curiosity and your
sense of joy at every discovery
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Acknowledgements
The work in this thesis is not the sole effort of one person, but an
accomplishment made possible by the help, support, and effort of a myriad of
individuals. From faculty and mentors to friends and colleagues, this work would not
have been possible without their presence in my life.
Central to all of this is my thesis advisor and committee chair, Dr. Geoff
Murphy. His guidance throughout my time in graduate school has lead me to be the
independent scientist I am today and I am forever grateful. I also need to thank the rest
of my thesis committee: Dr. Lori Isom, Dr. Audrey Seasholtz, Dr. Mike Sutton, and Dr.
Ed Stuenkel for their time and wisdom throughout the years in helping to guide my
research and my training experience. I would like to thank the neuroscience program
and all of the amazing people involved in the program including my fellow students, in
particular the students in my cohort, the staff, Rachel Harbach and Valerie Smith, and
all of the amazing faculty who have taught me or advised me throughout my time in the
program.
None of this work would have been possible without the help and support of all
of those I have worked with on a daily basis and have had the pleasure of calling
friends. To all of the undergraduates who have helped me throughout the years in the
maintenance of mouse lines and data collection I owe a big thanks. In particular, Ryan
Bell, Grace Fisher, and Reciton Pahumi, who have been incredibly helpful in the
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collection and processing of data pertaining to the work published in this thesis. I also
would like to thank the ladies in the lab: Shannon Moore, Ali Althaus, and Rachel
Parent who helped with the proofing and editing of various thesis chapters and figures,
as well as all the other past and current members of the lab for their support and
guidance throughout my time in graduate school including: Jamie Slater, Ben Throesch,
Lisa Stackhouse, Kasia Glanowska, Aislinn Williams.
I need to thank the many friends in my life: my two best friends, Erin
Buffington and Caitlin Orsini, all of my friends I have made in the program, including
my entering cohort, and my many friends outside of the program.
To my parents, Pedro and Raelynn Jimenez, I owe a big thank you. Throughout
my life, as well as my graduate career my parents have always been my biggest
supporters. From a young age they encouraged my sense of curiosity and discovery and
always supported my determination to succeed. I also need to thank my mother-in-law,
Miriam, and father-in-law, Ken, for their continual support, and my brothers Andre and
Dan and all of my brothers-in-law and sisters-in-law, Karsten Temme, Lauren Temme,
Marliese Peltier, Dan Peltier, Andrew Temme, and Hanna Temme, for all their love and
support.
Finally, I need to thank the loves of my life: my husband and my daughter. My
amazing husband Jacob has known me and been with me from the beginning of my
research career. He has always been by my side to celebrate my victories and to support
me when things don’t work out. He is my rock and without him, I wouldn’t be as strong
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as I am. To my daughter Catalina, your unconditional love and laughter brighten my life
and keep me going.

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Table of Contents
Dedication ii
Acknowledgements iii
List of Figures xii
List of Tables xv
List of Appendices xvi
List of Abbreviations xvii
Abstract xxi
CHAPTER 1: Introduction 1
1.1 Adaptive and maladaptive emotional learning 1
1.1.1 Pavlovian Conditioning 2
1.1.2 Fear Extinction 4
1.1.3 Maladaptive Fear 5
1.2 Neurobiology of learning 6
1.2.1 The Hippocampus 6
1.2.2 The Amygdala 8
1.3 Neurophysiological Basis of Learning 9
1.3.1 Synaptic Plasticity 10
1.3.2 Intrinsic Plasticity 13
1.4 Calcium as a neuronal modulator 16
1.4.1 Voltage gated calcium channels 16
1.4.2 L-type voltage gated calcium channels in learning and
Neurobiology 20
1.4.2.1 L-type voltage gated calcium channels in neurophysiology 20
1.4.2.2 L-type voltage gated calcium channels in learning and
behavior 22
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1.4.2.3 L-type voltage gated calcium channels in gene regulation and
neurogenesis 23
1.4.3 CaV1.2 voltage gated calcium channels in disease states 24
1.5 Aims 25
References 28
CHAPTER 2: Comparison of inbred mouse substrains reveals segregation of
maladaptive fear phenotypes 45
2.1 Summary 45
2.2 Introduction 46
2.3 Materials and Methods 49
2.3.1 Mice 49
2.3.2 Behavioral Procedures 49
2.3.2.1 Conditioning Apparatus and Contexts 49
2.3.2.2 Protocols 51
2.4 Results 53
2.4.1 Similar acquisition and consolidation of fear memories in 129S6
and C57B6 strains 53
2.4.2 Mouse strain 129S6 shows significant deficits in cued and
contextual fear extinction compared to C57B6 mice 54
2.4.3 Mouse Strain 129S6 shows comparable/normal levels of fear
generalization as C57B6 mice 57
2.4.4 Unlike 129S1 mice, 129S6 can be trained to discriminate between
similar contexts 59
2.4.5 Despite deficits in 129S6 mice, hybrid 129S6/B6 mice exhibit
normal fear extinction to a conditioned context 61
2.5 Discussion 62
References 69
CHAPTER 3: Neuronal deletion of Ca 1.2, but not Ca 1.3 impairs dentate
V V
gyrus associated memory tasks and adult neurogenesis 82
3.1 Summary 82
3.2 Introduction 83
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3.3 Materials and Methods 87
3.3.1 Mice 87
3.3.1.1 CaV1.2 Conditional knockout mice 88
3.3.1.2 CaV1.3 Conditional knockout mice 88
3.3.2 Behavioral Paradigm 89
3.3.2.1 Pavlovian Fear Conditioning 89
3.3.2.2 Context Discrimination 89
3.3.2.3 Classic Morris water maze 90
3.3.2.4 Limited Cues water maze 91
3.3.3 Cell Labeling 92
3.3.3.1 BrdU 92
3.3.3.2 Doublecortin 93
3.3.3.3 BrdU and Doublecortin Cell Counting 94
3.3.3.4 Dentate gyrus granular cell layer measurements 94
3.3.4 Statistical Analysis 95
3.4 Results 95
3.4.1 Conditional deletion of Ca 1.2 does not affect simple
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hippocampal dependent learning 95
3.4.2 Neuronal deletion of Ca 1.2 produces deficits in neurogenesis
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associated learning tasks 98
3.4.3 Neurogenesis and Cell Division in the Dentate Gyrus 102
3.4.4 Deletion of Ca 1.3 does not alter dentate gyrus associated learning
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tasks 104
3.5 Discussion 105
References 114
CHAPTER 4: The L-type voltage gated calcium channel, Ca 1.2 mediates
V
fear extinction and synaptic regulation of the lateral amygdala 128
4.1 Summary 128
4.2 Introduction 129
4.3 Materials and Methods 132
4.3.1 Mice 132
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