University of Pennsylvania ScholarlyCommons Publicly Accessible Penn Dissertations 2018 Olfactory Inputs Modulate Respiration-Related Activity In The Prefrontal Cortex And Fear Behavior Andrew Henry Moberly University of Pennsylvania, [email protected] Follow this and additional works at: https://repository.upenn.edu/edissertations Part of the Neuroscience and Neurobiology Commons Recommended Citation Moberly, Andrew Henry, "Olfactory Inputs Modulate Respiration-Related Activity In The Prefrontal Cortex And Fear Behavior" (2018). Publicly Accessible Penn Dissertations. 3161. https://repository.upenn.edu/edissertations/3161 This paper is posted at ScholarlyCommons. https://repository.upenn.edu/edissertations/3161 For more information, please contact [email protected]. Olfactory Inputs Modulate Respiration-Related Activity In The Prefrontal Cortex And Fear Behavior Abstract Voluntary control of respiration, especially via rhythmic nasal breathing, alleviates negative feelings such as fear and is used clinically to manage certain types of panic attacks. However, the neural substrates that link nasal breathing to fear circuits remains unknown. Here we show that during conditioned fear- induced freezing behavior, mice breathe at a steady rate (~4 Hz) which is strongly correlated with a predominant 4 Hz oscillation observed in the olfactory bulb and the prelimbic prefrontal cortex (plPFC), a structure critical for the expression of conditioned fear behaviors. We demonstrate anatomical and functional connectivity between the olfactory pathway and plPFC via circuit tracing and optogenetic approaches. Disrupting olfactory inputs significantly educesr the 4 Hz oscillation in the plPFC suggesting that respiration-related signals from the olfactory system play a role in entraining this fear-related signal. Surprisingly, we find that without olfactory inputs, freezing times are significantly prolonged. Collectively, our results indicate that olfactory inputs modulate rhythmic activity in fear circuits and suggest a neural pathway that may underlie the behavioral benefits of espirr ation-entrained olfactory signals. Degree Type Dissertation Degree Name Doctor of Philosophy (PhD) Graduate Group Neuroscience First Advisor Minghong Ma Keywords Olfaction, Prefrontal Cortex, Respiration Subject Categories Neuroscience and Neurobiology This dissertation is available at ScholarlyCommons: https://repository.upenn.edu/edissertations/3161 OLFACTORY INPUTS MODULATE RESPIRATION-RELATED ACTIVITY IN THE PREFRONTAL CORTEX AND FEAR BEHAVIOR Andrew Henry Moberly A DISSERTATION in Neuroscience Presented to the Faculties of the University of Pennsylvania in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy 2018 Supervisor of Dissertation: _______________________ Minghong Ma Professor of Neuroscience Graduate Group Chairperson: ________________________ Joshua Gold Professor of Neuroscience Dissertation Committee: Marc F Schmidt, Professor of Biology (Committee Chair) Wenqin Luo, Associate Professor of Neuroscience Jay A Gottfried, Professor of Neurology ACKOWLEDGEMENTS My advisor, Dr. Minghong Ma, provided me with immeasurable support over the course of my doctoral studies. More than anyone, she has shaped how I think about the brain and the scientific questions we need to ask in our efforts to understand it. As a mentor, she valued independent, creative, critical thinking above all. She gave me the freedom to pursue interesting scientific questions and, with an incredible degree of patience, ensured that we learned as much from our failures as from our successes. I couldn’t ask for a better scientific role model and I would be happy to achieve even a modicum of the respect she garners from the entire neuroscience community. I would like to thank my thesis committee: Drs. Marc Schmidt, Diego Contreras, Jay Gottfried, and Wenqin Luo. Their intellectual input has been incredibly helpful and I am grateful for the support they provided over the course of my thesis work. Our collaboration with Wenqin deserves a special mention; I benefited greatly from Wenqin’s expertise thanks to the synergistic partnership between the Ma and Luo labs. I am deeply thankful to the past members of the Ma lab including Drs. Rosemary Challis and Yiqun Yu, and the visiting students Shaohau Zhao, Wenbin Yin, Liujing Zhuang, and Julia Mohrhardt. Without their contributions this work would not have been possible. The current members of the Ma lab were instrumental in generating and analyzing data that are presented here including Mary Schreck, Emma Janke, and Drs. Janardhan Bhattarai, and Yun-Feng Zhang. As I mentioned above, I was lucky to receive assistance from many members of the Luo lab and I would like to specifically thank Drs. Will Olsen, Kim Kridsada-Chu, Lian Ciu, and Ishmail Abdus-Saboor for ii their help and feedback over the years. I thank the veterinary staff and ULAR for providing the essential infrastructure for animal research at Penn. Thanks are also due to the experimental subjects for their contribution to this research. It was an incredible privilege to be part of the Neuroscience Graduate Group at the University of Pennsylvania. I thank the individuals that tirelessly ensure the program produces exceptional research scientists. This includes the program coordinators past and present: Jane Hoshi, Christine Clay, and Tom Hindman, the program chair Dr. Josh Gold, and the many faculty members who dedicate their time to teaching Cores II, and III. The program is strong because it attracts talented, hardworking, brilliant students – many of whom I am proud to call my friends. I thank Drs. Peter Dong, Greg Artiushin, Sarah Maguire, Kamesh Krishnamurthy, Chris Angelakos, and Preetika Gupta for sharing their companionship, rapport, and countless laughs with me throughout my time in the neuroscience program. I also have to thank my partner Jennifer Blackwell who has been my constant companion through grad school. When we first met I was in awe of how intelligent and true-to-herself she was. Later, I learned she compliments me well because she is willing to kill the bugs that make it into the apartment. My path to neuroscience research began when I signed up for a required undergraduate elective with the dubious placeholder title of: ‘Advanced Topics in Psychobiology’. Luckily, it turned out to be a course called ‘The Neuroscience of Smell’ taught by Dr. John McGann. As a new faculty member in the department of Behavioral Neuroscience John gave me the opportunity to work in his lab doing state-of-the-art brain research, for which I am forever grateful. John’s students were Drs. Lindsey Czarnecki and Marley Kass who became my first graduate student role models. Throughout iii graduate school I have strived to follow in their footsteps and use their work-ethic and passion for science to guide my own research. I thank them for everything they taught me. Of course, anything I have managed to achieve is entirely due to the love of my parents, Linh and Jim Moberly and sister Alyssa Moberly. Words do not suffice in thanking my family for their encouragement and support and I do my best to make them proud every day. Although it may be cliché, I’d like to invoke Newton’s expression, “If I have seen further it is by standing on the shoulders of giants”, and give my deepest thanks to all of the giants who have supported me. iv ABSTRACT OLFACTORY INPUTS MODULATE RESPIRATION-RELATED ACTIVITY IN THE PREFRONTAL CORTEX AND FEAR BEHAVIOR Andrew H Moberly Minghong Ma Voluntary control of respiration, especially via rhythmic nasal breathing, alleviates negative feelings such as fear and is used clinically to manage certain types of panic attacks. However, the neural substrates that link nasal breathing to fear circuits remains unknown. Here we show that during conditioned fear-induced freezing behavior, mice breathe at a steady rate (~4 Hz) which is strongly correlated with a predominant 4 Hz oscillation observed in the olfactory bulb and the prelimbic prefrontal cortex (plPFC), a structure critical for the expression of conditioned fear behaviors. We demonstrate anatomical and functional connectivity between the olfactory pathway and plPFC via circuit tracing and optogenetic approaches. Disrupting olfactory inputs significantly reduces the 4 Hz oscillation in the plPFC suggesting that respiration-related signals from the olfactory system play a role in entraining this fear-related signal. Surprisingly, we find that without olfactory inputs, freezing times are significantly prolonged. Collectively, our results indicate that olfactory inputs modulate rhythmic activity in fear circuits and suggest a neural pathway that may underlie the behavioral benefits of respiration-entrained olfactory signals. v TABLE OF CONTENTS ACKOWLEDGEMENTS ......................................................................................................... II ABSTRACT ................................................................................................................................ V LIST OF TABLES ................................................................................................................. VIII LIST OF FIGURES .................................................................................................................. IX CHAPTER 1: INTRODUCTION ............................................................................................ 1 The breathing rhythm .........................................................................................................................