Symposiums

"And the Beat Goes On: A Short Symposium Celebrating the Career of Professor Patsy Dickinson"

Saturday, April 1, 2023
2:00 pm, Kresge, VAC

Patsy Dickinson, Josiah Little Professor of Natural Sciences is a noted scientist studying the ability of the nervous system to generate flexibility in patterned movements. Originally from New Mexico, she earned her BA from Pomona College in 1973, a MS and PhD from the University of Washington in 1976 and 1979. She completed her postdoctoral research at the Laboratoire de Neurobiologie Comparée, Centre National de la Recherche Scientifique and Université de Bordeaux I, Arcachon, France from 1979-1981. She was a Visiting Assistant Professor at the University of Kentucky from 1981 to 1983, and arrived at Bowdoin in the fall of 1983. She has taught courses ranging from introductory biology to upper level seminars in neuroscience. Her teaching specialties are at the organismal level, where she teaches Neurophysiology and Comparative Physiology courses. 

While an Assistant Professor, Patsy was awarded a Mary Ingraham Bunting Institute Science Fellowship from Radcliffe College to spend a year doing research at Brandeis University and the Radcliffe Institute. She was awarded an NIH Fogarty Senior Fellowship and a fellowship from the John Simon Guggenheim Memorial Foundation to enable her to spend a year conducting research in Bordeaux , France in 1999-2000. Other awards include being named Educator of the Year by the Faculty for Undergraduate Neuroscience in 2012, and being invited to join the Dana Alliance for Brain Initiatives in 2015.

During the time she was at Bowdoin, Patsy’s research was supported by grants from a number of sources. She was awarded 9 research grants from the National Science Foundation, as well as one from the Whitehall Foundation. She was also a collaborator or co-PI on two other NSF grants and 2 grants from the Human Frontier Science Project.  In addition to grants funding her research, she was involved in grant support for teaching and supporting undergraduate research at Bowdoin. For example, she was awarded an NSF Instrumentation and Laboratory Improvement grant, and headed two grants for undergraduate education from the Howard Hughes Medical Institute, as well as leading the Bowdoin component of a statewide grant from the National Institutes of Health (the Idea Network for Biological Research Excellence, INBRE) from 2004-2022.

During the time she has been at Bowdoin, over 150 students have conducted research in Patsy’s lab, either in the summer or during the academic year, and often both. Students participating in research in her lab have made major contributions to the ongoing research in the lab, often generating data that have been published in major peer-reviewed journals. Of the 76 papers that Patsy has published during her time at Bowdoin, 54 include one or more students as co-authors. Many of these students have gone on to pursue careers in health-related fields or have earned PhDs in the biological sciences.

Patsy’s research has contributed to our understanding of the mechanisms by which rhythmic movements can be altered.  She and her collaborators were the first to identify and record from a single modulatory neuron, which, when activated, altered the output of a defined neuronal network (the stomatogastric system in the lobster).  She was also one of the first to elucidate some of the mechanisms that underlie the coordination of multiple rhythmic movement patterns.  Additionally, she made major contributions to our understanding of mechanisms by which and the extent to which neuronal circuits are modulated by neuropeptides. Her collaborations with other neurophysiologists, molecular biologists, biomechanics, and analytical chemists were crucial in enabling this array of discoveries.  

Guest Speakers

Dr. Eve Marder
Victor and Gwendolyn Beinfield Professor of Biology
Brandeis University

Title
From Modulation of Small Degenerate Circuits to Climate Change

Abstract
The crustacean stomatogastric nervous system houses two important central pattern generating circuits that generate the fast pyloric rhythm and the slower gastric mill rhythm.  Numerous studies have demonstrated that individual neurons and these small circuits are degenerate, that is, different sets of underlying intrinsic and synaptic currents can produce very similar motor patterns.  This raises the question of whether these degenerate solutions can respond robustly and reliably to perturbations. Consequently, we have been studying a number of global perturbations, including temperature, pH, and high extracellular potassium concentrations.  While both the pyloric and gastric mill rhythms can operate over a range of temperatures, analysis of data collected over many years shows that ocean temperatures are correlated with the range over which these rhythms can function reliably.  Moreover, many long-term perturbations produce "cryptic" changes that are not visible in the absence of perturbation, but are only revealed when the systems are challenged.  These data give potential insight into how prior history can produce hidden changes in circuit function that change the reliance of circuits to future perturbations.   

Dr Michael Nusbaum
Professor of Neuroscience
Perelman School of Medicine
University of Pennsylvania

Title

Hormonal Tuning of Specific Circuit States

Abstract
Rhythmically active neural circuits are multifunctional constructs (i.e. the same circuit is configured into different circuit states, which often generate different activity patterns, due to neuromodulator-mediated changes in the electrophysiological properties of the circuit neurons). Thus far, studies in the isolated nervous system of how different circuit states respond to perturbations have primarily evaluated the impact of individual influences using arbitrary parameters, such as applying single hormones at specific concentrations. However, neural circuits in vivo likely receive parallel influences with varying parameters. Further, parallel influences can have non-linear actions that are distinct from their individual actions. 

Here, we are determining how different neural circuit states respond to a complete, natural source of circulating hormones. Specifically, we are applying hemolymph (blood), via which hormones gain access to the nervous system, from an unfed Cancer borealis crab ('unfed hemolymph') onto the isolated stomatogastric ganglion from a different unfed crab to determine the hemolymph influence on different gastric mill (chewing) and pyloric (passage of chewed food) circuit states. Subsequently, we will use mass spectrometry to identify the hormone(s) responsible for these hemolymph actions. Thus far, the different gastric mill circuit states configured by two unrelated neuropeptide modulators (Gly1-SIFamide, CabTRP Ia) continued to generate their circuit state-specific gastric mill rhythms in unfed hemolymph, but each of these rhythms was substantially strengthened and prolonged. The circuit state-specific pyloric rhythms elicited by these peptides were also enhanced, but only modestly, without a pattern change by unfed hemolymph. The hemolymph ability to strengthen the rhythms without changing their patterns suggests that one or more hormones in the hemolymph are increasing the effectiveness of Gly1-SIFamide and CabTRP Ia either directly or by having equivalent actions on the same circuit neurons. 

The ability to study how the complete population of hormones, at their behaviorally-relevant concentrations, from a particular behavioral state influences distinct circuit states in the isolated nervous system extends the value of the isolated nervous system preparation for discerning cellular, synaptic and circuit-level events underlying neural circuit operation. 

Dr. Alex Williams
Assistant Professor of Neural Science
NYU

Title
Variability in neural circuits: from crustaceans to mammalian cortex

Abstract
Individual variability is a core principle of biology, but studying this principle in neural circuits is challenging. Over the past several decades, crustacean neurobiologists played a central role in demonstrating the pervasiveness of variability in neural circuits and its profound implications for theories of neural computation. Crustacean central pattern generators (CPGs) are ideally suited to this subject for several reasons. Perhaps most critically, many neurons can be functionally identified and matched on a one-to-one basis across experimental subjects. Patsy and her colleagues have convincingly shown that neurons of the same type can exhibit variable (even opposite) responses to the same experimental perturbation. This is a fundamental result, but how can we quantify and study it in larger circuits where neurons are not one-to-one matched across preparations? My talk will describe a nascent literature on this question and a possible path to rigorously study variability in experiments involving hundreds to thousands of extracellularly recorded neurons.

Evyn Dickinson (PhD Candidate)
Yale University

Title
Balancing sensory inputs: olfactory and thermosensory guided behaviors in fruit flies

Abstract
Organisms are constantly bombarded with environmental information across multiple sensory streams. Determining which information to retain, which information to combine, and which information to keep separate is a nontrivial task for the brain. However, it is poorly understood how the brain implements integrations of relevant sensory information across modalities. The fruit fly, Drosophila melanogaster, offers a unique opportunity to study flexible interactions of two sensory modalities – temperature and olfaction – that interact to optimize an essential behavior: feeding. Flies rely heavily on their olfactory system to locate and select appropriate food sources. In general, flies sample the concentration of attractive food related chemicals that have been volatized into the air and use changes in these concentration gradients to navigate to their food source. Additionally, as small poikilotherms, they are highly susceptible to environmental changes in temperature while navigating the world. We are investigating when and how temperature modulates olfactory guided feeding in flies using novel behavioral assays, genetic screening, and physiological approaches. We have found that temperature robustly modulates flies’ behavioral attraction to food odors. Specifically, attraction decreases linearly as temperatures move away from the preferred temperature range of Drosophila (~24-27⁰C); conversely, attraction increases nonlinearly as temperatures approach the preferred temperature range. Taken together, our results show that flies employ a behavioral strategy which maximizes feeding opportunities in dynamic and fluctuating temperature environments.

Reception immediately following at 5:15 p.m. in Main Lounge, Moulton Union. Please RSVP here.

Sponsored by the Departments of Biology, Neuroscience Program and the Moulton Fund

FMI, please contact Rebecca Banks at rbanks@bowdoin.edu.