Graduates of the Crook Lab Masters Program
Diana Neacsu - (graduated Spring 2024 - Diana is now a PhD student at KU Leuven in Belgium)
I am an international master’s student in the Physiology and Behavioral program at San Francisco State University. I completed my bachelor’s degree in Biology at the University of Waterloo in Canada. I am interested in visualizing the nervous system of cephalopod limbs to provide new insight and improve our understanding of how these limbs are able to move in sophisticated and complex ways.
My master’s thesis focuses on building a connectome of the nervous structures within the arm of the Pygmy octopus, Octopus bocki. A connectome is a 3-dimensional visualization of all of the neuronal processes involved in a system including cell bodies, axons, dendrites, and glial cells that may be present. The 3-dimensionality of this type of research allows us to not only view the system at various angles but also gives us the opportunity to find patterns of organization that might not be visible in a 2-dimensional image. By using the software program Reconstruct, I will focus on tracing the axonal tracts that run throughout the entirety of the arm and the cells that compromise the sucker ganglia which are responsible for controlling the musculature of the suckers. I will also participate in guiding undergrads to accurately trace cells found within the intramuscular nerve cords in a collaborative effort with WEBKNOSSOS.
After graduating from SFSU, I plan on pursuing a PhD in marine biology in order to continue researching cephalopods.
Diana is supported by an Allen Distinguished Investigator Grant from the Frontiers Group of the Allen Foundation, to investigate motor circuit organization in cephalopods.
Abbigale Koenigsmark (graduated Spring 2023 - Abbi is now a PhD student in the Neuroscience Program at the University of Oregon)
“I am a master’s student in the Physiology and Behavioral Biology Program at SFSU. I’m interested in the effect of injury on cephalopod mating behavior.
I completed my B.S. at University of Maryland where I majored in Ecology and Evolution and minored in Statistics. There I wrote my undergraduate thesis in Dr. Alexa Bely’s lab, researching the effect of sediment shifting from stream flooding on annelid injury and recovery.
My master’s thesis focuses on understanding how injury affects stumpy-spined cuttlefish (Sepia bandensis) mating behavior, specifically during male-male contests. To gain access to mates, male cuttlefish with engage in periods of signaling which may escalate to physical fighting. I aim to categorize the signaling behavior and any associated body patterns during these contests and assess how contests differ when one male has experienced an injury that would be common in the wild. Furthermore, I also aim to assess the role of nociceptive sensitization in mitigating any negative effects of injury on these male contests. Nociceptive sensitization has previously been shown to play a compensatory role by decreasing risk of predation after injury. My project is the first to ever assess the potentially beneficial effects of nociceptive sensitization on any reproductive behavior. I am also leading a team of undergraduates on a separate project assessing sex differences in the detection and nociceptive thresholds of the hummingbird bobtail squid (Euprymna berryi).
After graduation I’m planning on pursuing a PhD in biology and continue researching animal behavior.”
Abbi was supported by an NSF CAREER grant to the lab to study the ecological effects of injury and nociceptive sensitization
Abbi’s paper on sex differences in cuttlefish contests is coming soon!
Rachel Parsons - (graduated Spring 2023 - Rachel is applying for PhD admission in the 23/24 cycle).
“I am a master’s student in the Physiology and Behavioral Biology program at SFSU. I completed my bachelor’s degree in Marine Biology at the University of California San Diego. I am drawn towards sensory biology and the physiology of marine organisms.
In the Crook Lab, I have performed behavioral experiments on juvenile and senescent squid to understand the role of anesthesia on these animals at different life stages. Using Bobtail squid as the model organism allows us to better grasp the effects of anesthesia on invertebrates, specifically on a species that does not have extensive studies on the behavioral and neurological effects at different life stages.
My thesis project revolves around the neural organization for locomotion patterns of flamboyant cuttlefish. Specifically, the control of the ventral papillae which this genus uses to perform coordinated alternate stepping. This walking will be examined via DeepLabCut, a machine learning pose estimation software that can compare the relationships of the four limbs and allow analysis of gait patterns.
After graduation from San Francisco State University, I plan to obtain my PhD with my ultimate goal being to become a PI and run a lab in academia.”
Rachel was supported by an Allen Distinguished Investigator Grant from the Frontiers Group of the Allen Foundation, to investigate motor circuit organization in cephalopods
Rachel’s paper on locomotion in M. pfefferi is coming soon!
Meghan Holst, MS 2021
Meghan Holst (graduated Spring 2021 - Meghan is currently a PhD student in Ecology at UC Davis.
“I am a Masters student in the Physiology and Behavior program at San Francisco State University. I am also a biologist at Aquarium of the Bay in San Francisco. For my Master’s thesis, I am interested in studying the decline in Giant Pacific Octopus (GPO), Enteroctopus dofleini as they go through senescence (terminal reproduction). Similar to salmon's reproductive life cycle, cephalopods undergo major physical deterioration during this time. Senescent octopuses have a myriad of symptoms that vary from each individual, but always include anorexia, deterioration of the skin, sinking of the eyes, and stereotypic repetitive behaviors. As octopus slowly decline and deteriorate, facilities housing them question how ethical it is to allow animals to experience extended terminal decline. However, it is currently unknown how octopuses experience senescence physically and mentally.
I hypothesize that as GPO’s decline, their nervous system also declines. The nervous system is responsible for sensing stimuli from the environment and sending this message to the central brain. If the nervous system is degrading, I hypothesize that GPO’s ability to sense stimulus will decline. To test this, I am measuring how GPO’s respond to the same stimulus over time. I expect that GPO’s will have a decrease in stimulus response as they continue through senescence until eventual death. Understanding how GPO’s perceive their environment and translate stimulus will the be first step towards understanding how they experience senescence. This research will produce information critical for making ethical welfare decisions of octopus on display or in lab settings worldwide.
I am collaborating with multiple aquariums across the country to study captive GPO’s. It is my intention that through collaboration, our industry will have a better understanding of senescence in GPO’s and how their deterioration may influence their well-being.
Upon receiving my M.S. in Physiology and Behavior, I plan to complete a Ph.D. that will complement the research I conduct at Aquarium of the Bay. Research conducted with SFSU and a future Ph.D. program will contribute to Aquarium of the Bay’s mission to protect, restore, and inspire conservation.”
Meghan’s paper on senescence in GPOs was published in 2022 in Comp. Biochem & Physiol. A. Read it here.
Stephanie Bazarini, MS 2019.
Stephanie Bazarini (graduated Spring 2019 - Stephanie was previously a PhD student at UCSB and is now the assistant director of the Student Enrichment Office at SFSU).
“I’m a Masters student in the Physiology and Behavior program at SFSU.
I'm interested in the physiological factors that pre-dispose women to chronic pain, particularly how fluctuations in female reproductive hormones can affect neural sensitization. I am using the Hawaiian bobtail squid as a comparative model to examine whether estrogen influences nociceptive sensitivity after injury. The females of this species express estrogen receptors, but do not undergo estrous cycles like mammals do.
I am exposing groups of injured and uninjured squid to either no, chronic, or acute doses of estrogen in tank water and comparing neuroanatomy, behavior and neural excitability among the treatments. The estrogen exposures are designed to either replicate the effect of chronic environmental exposures throughout development or to mimic the interaction of an acute estrogen peak co-incident with inflammation. I hypothesize that estrogen exposure increases estrogen receptor and dendritic spine density in developing brains, and greater behavioral and neural sensitization after injury. However preliminary data suggests that estrogen-exposure reduces neural responses to injury.
My hope is that this work will increase our understanding of conserved mechanisms of estrogen/injury interactions and provide new insight into existing mammalian pain studies. Additionally, this work will improve our knowledge of the effects of environmental estrogens.
My goal is to earn a PhD in a Neuroscience program where I can continue to research the role that steroid hormones play in disease states that disproportionately affect women.
I have taught the BIOL 230 (Introductory Biology for Majors) Lab class for three semesters and really enjoy getting to share my love for biology with students at the beginning of their university careers. I have also worked as a GA for the Neural Systems (BIOL 642) and Hormones and Behavior (BIOL 622) classes. I am very honored to have been selected as and ARCS (Achievement Reward for College Scientists) scholar for the 2018 – 2019 academic year.”
Stephanie was funded by the ARCS Foundation Scholarship program.
Stephanie’s paper on estrogen and nociception in squid was published in J. Exp. Biol. in 2020; read it here
Ryan Howard, MS 2019
Ryan Howard (graduated Spring 2019 - Ryan is currently pursuing his PhD at Auckland University of Technology)
“I’m a Masters student in the Marine Biology program at SFSU.Research experiences in the Great Barrier Reef and along the Costa Rican coast introduced me to cephalopods and their breathtaking rapid adaptive camouflage. Pursuing research to understand this complex behavior led me to the Crook Lab where I study how minor tissue injury to their adaptive skin affects camouflage behaviors of Indo-Pacific octopuses.
Adaptive camouflage has evolved independently several times both in terrestrial and aquatic species, and though it’s a widespread defensive strategy, little research exists explaining how organisms compensate when superficial injuries disrupt camouflage patterns. Octopuses are phenomenal model organisms for studying this dynamic because of their ability to adjust their camouflage displays in less than a second.
My research is focused on determining the roles nociceptive sensitization and visual self-referencing play when octopuses make camouflage decisions after being superficially injured. By creating sham and true superficial injuries I can regulate which sensory input mechanism is accessible to the study subjects. I’m then able to quantify the camouflage components (e.g. color and luminance) and compare treatment groups with image analysis software. I hypothesize that octopuses utilize sensory input from both nociceptive sensitization and visual self-referencing to influence their camouflage behaviors.
This project is designed to provide insight into the sensory mechanisms utilized by octopuses for implementing their complex camouflage behavior. My hope is that this research will produce significant findings that will inspire researchers to ask similar questions in other model organisms that uses adaptive camouflage.
I’m honored to be a NIH MA-MS/Ph.D. Bridge to the Future Fellow while earning my M.S. degree from SFSU. After graduation, I’m committed to continuing my education in an Ecology and Evolutionary Biology Ph.D. program, where I plan to study cephalopod behavior and ecology. My ultimate goal is to actively support underrepresented groups achieve their dreams of becoming STEM researchers by partnering with organizations such as the Society for Advancement of Chicanos/Hispanics and Native Americans in Science (SACNAS).”
Ryan was supported by an NIH-Bridge Fellowship.
Ryan’s paper on early-life injury in squid was published in 2019 in Phil.. Trans. R. Soc. B.; read it here
Vivien Enriquez, MS 2019
Vivien Enriquez (graduated Spring 2019 - Vivien is currently the director of undergraduate research at University of Vermont).
“I am master's student in the Physiology and Behavior program at SFSU.
With a diverse background in biological anthropology, wildlife conservation, and animal behavior my graduate research explores questions related to how microorganisms influence characteristic animal host behavior and survival. Microorganisms, such as bacteria, viruses, and fungi dominate the natural world in terms
of sheer abundance and are consistently offering new insight into their role in animal development, health, and behavior.
Using the Hawaiian bobtail squid-Vibrio fischeri model, I am investigating how the bioluminescent, bacterial symbiont (Vibrio fischeri) impacts a suite of host behaviors, such as swimming and foraging, and survival throughout multiple stages of the squids' development. To examine these impacts, I am conducting behavioral observations through experiments that manipulate the colonization process by rearing squid in the presence or absence of V. fischeri.
Completing this research will add to our existing knowledge about this rigorously studied model system and will provide insight into how V. fischeri may offer more to its host than bioluminescence. I hope the completion of this study will serve as a jumping-off point for additional research questions which tackle the mechanisms behind why bacterial symbionts may be key for host survival.
Upon receiving my M.S. degree from SFSU, I plan to continue my studies in animal behavior and host-symbiont interactions by completing a Ph.D. program in Ecology and Evolutionary Biology. I am thrilled to have conducted my research in the Department of Biology at SFSU as an NIH Research Initiative for Scientific Enhancement (RISE) Fellow and California State University Sally Casanova Pre-Doctoral Scholar.”
Vivien was funded by the NIH-RISE fellowship program.