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Hoynoski J, Dohn J, Franzen AD, Burrell BD. Repetitive nociceptive stimulation elicits complex behavioral changes in Hirudo: evidence of arousal and motivational adaptations. J Exp Biol 2023; 226:jeb245895. [PMID: 37497630 PMCID: PMC10445732 DOI: 10.1242/jeb.245895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 07/20/2023] [Indexed: 07/28/2023]
Abstract
Appropriate responses to real or potential damaging stimuli to the body (nociception) are critical to an animal's short- and long-term survival. The initial goal of this study was to examine habituation of withdrawal reflexes (whole-body and local shortening) to repeated mechanical nociceptive stimuli (needle pokes) in the medicinal leech, Hirudo verbana, and assess whether injury altered habituation to these nociceptive stimuli. While repeated needle pokes did reduce shortening in H. verbana, a second set of behavior changes was observed. Specifically, animals began to evade subsequent stimuli by either hiding their posterior sucker underneath adjacent body segments or engaging in locomotion (crawling). Animals differed in terms of how quickly they adopted evasion behaviors during repeated stimulation, exhibiting a multi-modal distribution for early, intermediate and late evaders. Prior injury had a profound effect on this transition, decreasing the time frame in which animals began to carry out evasion and increasing the magnitude of these evasion behaviors (more locomotory evasion). The data indicate the presence in Hirudo of a complex and adaptive defensive arousal process to avoid noxious stimuli that is influenced by differences in internal states, prior experience with injury of the stimulated areas, and possibly learning-based processes.
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Affiliation(s)
- Jessica Hoynoski
- Division of Basic Biomedical Sciences, Center for Brain and Behavioral Research (CBBRe), Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - John Dohn
- Division of Basic Biomedical Sciences, Center for Brain and Behavioral Research (CBBRe), Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - Avery D. Franzen
- Division of Basic Biomedical Sciences, Center for Brain and Behavioral Research (CBBRe), Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - Brian D. Burrell
- Division of Basic Biomedical Sciences, Center for Brain and Behavioral Research (CBBRe), Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
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2
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Kaynezhad P, Tachtsidis I, Aboelnour A, Sivaprasad S, Jeffery G. Watching synchronous mitochondrial respiration in the retina and its instability in a mouse model of macular degeneration. Sci Rep 2021; 11:3274. [PMID: 33558624 PMCID: PMC7870852 DOI: 10.1038/s41598-021-82811-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 01/12/2021] [Indexed: 11/09/2022] Open
Abstract
Mitochondrial function declines with age and in some diseases, but we have been unable to analyze this in vivo. Here, we optically examine retinal mitochondrial function as well as choroidal oxygenation and hemodynamics in aging C57 and complement factor H (CFH-/-) mice, proposed models of macular degeneration which suffer early retinal mitochondrial decline. In young C57s mitochondrial populations respire in coupled oscillatory behavior in cycles of ~ 8 min, which is phase linked to choroidal oscillatory hemodynamics. In aging C57s, the oscillations are less regular being ~ 14 min and more dissociated from choroidal hemodynamics. The mitochondrial oscillatory cycles are extended in CFH-/- mice being ~ 16 min and are further dissociated from choroidal hemodynamics. Mitochondrial decline occurs before age-related changes to choroidal vasculature, hence, is the likely origin of oscillatory disruption in hemodynamics. This technology offers a non-invasive technique to detect early retinal disease and its relationship to blood oxygenation in vivo and in real time.
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Affiliation(s)
- Pardis Kaynezhad
- Institute of Ophthalmology, University College London, London, EC1V 9EL, UK
| | - Ilias Tachtsidis
- Department of Medical Physics and Biomedical Engineering, University College London, London, WC1E 6BT, UK
| | - Asmaa Aboelnour
- Histology and Cytology Department, Faculty of Veterinary Medicine, Damanhour University, Damanhour, Egypt
| | - Sobha Sivaprasad
- Institute of Ophthalmology, University College London, London, EC1V 9EL, UK
| | - Glen Jeffery
- Institute of Ophthalmology, University College London, London, EC1V 9EL, UK.
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3
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Berkowitz A. Expanding our horizons: central pattern generation in the context of complex activity sequences. J Exp Biol 2019; 222:222/20/jeb192054. [DOI: 10.1242/jeb.192054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
ABSTRACT
Central pattern generators (CPGs) are central nervous system (CNS) networks that can generate coordinated output in the absence of patterned sensory input. For decades, this concept was applied almost exclusively to simple, innate, rhythmic movements with essentially identical cycles that repeat continually (e.g. respiration) or episodically (e.g. locomotion). But many natural movement sequences are not simple rhythms, as they include different elements in a complex order, and some involve learning. The concepts and experimental approaches of CPG research have also been applied to the neural control of complex movement sequences, such as birdsong, though this is not widely appreciated. Experimental approaches to the investigation of CPG networks, both for simple rhythms and for complex activity sequences, have shown that: (1) brief activation of the CPG elicits a long-lasting naturalistic activity sequence; (2) electrical stimulation of CPG elements alters the timing of subsequent cycles or sequence elements; and (3) warming or cooling CPG elements respectively speeds up or slows down the rhythm or sequence rate. The CPG concept has also been applied to the activity rhythms of populations of mammalian cortical neurons. CPG concepts and methods might further be applied to a variety of fixed action patterns typically used in courtship, rivalry, nest building and prey capture. These complex movements could be generated by CPGs within CPGs (‘nested’ CPGs). Stereotypical, non-motor, non-rhythmic neuronal activity sequences may also be generated by CPGs. My goal here is to highlight previous applications of the CPG concept to complex but stereotypical activity sequences and to suggest additional possible applications, which might provoke new hypotheses and experiments.
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Affiliation(s)
- Ari Berkowitz
- Department of Biology and Cellular & Behavioral Neurobiology Graduate Program, University of Oklahoma, Norman, OK 73019, USA
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White RS, Spencer RM, Nusbaum MP, Blitz DM. State-dependent sensorimotor gating in a rhythmic motor system. J Neurophysiol 2017; 118:2806-2818. [PMID: 28814634 DOI: 10.1152/jn.00420.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/14/2017] [Accepted: 08/14/2017] [Indexed: 11/22/2022] Open
Abstract
Sensory feedback influences motor circuits and/or their projection neuron inputs to adjust ongoing motor activity, but its efficacy varies. Currently, less is known about regulation of sensory feedback onto projection neurons that control downstream motor circuits than about sensory regulation of the motor circuit neurons themselves. In this study, we tested whether sensory feedback onto projection neurons is sensitive only to activation of a motor system, or also to the modulatory state underlying that activation, using the crab Cancer borealis stomatogastric nervous system. We examined how proprioceptor neurons (gastropyloric receptors, GPRs) influence the gastric mill (chewing) circuit neurons and the projection neurons (MCN1, CPN2) that drive the gastric mill rhythm. During gastric mill rhythms triggered by the mechanosensory ventral cardiac neurons (VCNs), GPR was shown previously to influence gastric mill circuit neurons, but its excitation of MCN1/CPN2 was absent. In this study, we tested whether GPR effects on MCN1/CPN2 are also absent during gastric mill rhythms triggered by the peptidergic postoesophageal commissure (POC) neurons. The VCN and POC pathways both trigger lasting MCN1/CPN2 activation, but their distinct influence on circuit feedback to these neurons produces different gastric mill motor patterns. We show that GPR excites MCN1 and CPN2 during the POC-gastric mill rhythm, altering their firing rates and activity patterns. This action changes both phases of the POC-gastric mill rhythm, whereas GPR only alters one phase of the VCN-gastric mill rhythm. Thus sensory feedback to projection neurons can be gated as a function of the modulatory state of an active motor system, not simply switched on/off with the onset of motor activity.NEW & NOTEWORTHY Sensory feedback influences motor systems (i.e., motor circuits and their projection neuron inputs). However, whether regulation of sensory feedback to these projection neurons is consistent across different versions of the same motor pattern driven by the same motor system was not known. We found that gating of sensory feedback to projection neurons is determined by the modulatory state of the motor system, and not simply by whether the system is active or inactive.
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Affiliation(s)
- Rachel S White
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Michael P Nusbaum
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Dawn M Blitz
- Department of Biology, Miami University, Oxford, Ohio; and
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5
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Palmer CR, Barnett MN, Copado S, Gardezy F, Kristan WB. Multiplexed modulation of behavioral choice. J Exp Biol 2014; 217:2963-73. [PMID: 24902753 PMCID: PMC4132565 DOI: 10.1242/jeb.098749] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 06/01/2014] [Indexed: 11/20/2022]
Abstract
Stimuli in the environment, as well as internal states, influence behavioral choice. Of course, animals are often exposed to multiple external and internal factors simultaneously, which makes the ultimate determinants of behavior quite complex. We observed the behavioral responses of European leeches, Hirudo verbana, as we varied one external factor (surrounding water depth) with either another external factor (location of tactile stimulation along the body) or an internal factor (body distention following feeding). Stimulus location proved to be the primary indicator of behavioral response. In general, anterior stimulation produced shortening behavior, midbody stimulation produced local bending, and posterior stimulation usually produced either swimming or crawling but sometimes a hybrid of the two. By producing a systematically measured map of behavioral responses to body stimulation, we found wide areas of overlap between behaviors. When we varied the surrounding water depth, this map changed significantly, and a new feature - rotation of the body along its long axis prior to swimming - appeared. We found additional interactions between water depth and time since last feeding. A large blood meal initially made the animals crawl more and swim less, an effect that was attenuated as water depth increased. The behavioral map returned to its pre-feeding form after approximately 3 weeks as the leeches digested their blood meal. In summary, we found multiplexed impacts on behavioral choice, with the map of responses to tactile stimulation modified by water depth, which itself modulated the impact that feeding had on the decision to swim or crawl.
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Affiliation(s)
- Chris R Palmer
- Department of Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Megan N Barnett
- Department of Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Saul Copado
- Department of Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Fred Gardezy
- Department of Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - William B Kristan
- Department of Biology, University of California, San Diego, La Jolla, CA 92093, USA
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6
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Puhl JG, Masino MA, Mesce KA. Necessary, sufficient and permissive: a single locomotor command neuron important for intersegmental coordination. J Neurosci 2012; 32:17646-57. [PMID: 23223287 PMCID: PMC3538829 DOI: 10.1523/jneurosci.2249-12.2012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 10/10/2012] [Accepted: 10/13/2012] [Indexed: 11/21/2022] Open
Abstract
In this report we posed the overarching question: What multiple contributions can a single neuron have on controlling the behavior of an animal, especially within a given context? To address this timely question, we studied the neuron R3b-1 in the medicinal leech. This bilaterally paired neuron descends from the cephalic ganglion and projects uninterrupted through the segmental ganglia comprising the nerve cord; its terminal arbors invade each hemi-ganglion. We discovered that a single R3b-1 neuron functions as a command neuron in the strictest sense, as it was both necessary and sufficient for fictive crawling behavior. Aside from these command-related properties, we determined that R3b-1 modulates the cycle period of crawl motor activity. R3b-1 has previously been shown to activate swimming behavior, but when the CNS was exposed to dopamine (DA), crawling became the exclusive locomotor pattern produced by R3b-1. DA exposure also led to bursting in R3b-1 that matched periods observed during fictive crawling, even when potential ascending inputs from crawl oscillators were removed. Although the above attributes render R3b-1 an intriguing cell, it is its ability to permit the coordination of the segmentally distributed crawl oscillators that makes this multifunctional neuron so notable. To our knowledge, this cell provides the first biological example of a single command neuron that is also vital for the intersegmental coordination of a locomotor behavior. Furthermore, our study highlights the importance of DA as an internal contextual cue that can integrate functional layers of the nervous system for adaptive behavior.
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Affiliation(s)
| | - Mark A. Masino
- Graduate Program in Neuroscience, and
- Neuroscience, University of Minnesota, Saint Paul, Minnesota 55108
| | - Karen A. Mesce
- Graduate Program in Neuroscience, and
- Departments of Entomology and
- Neuroscience, University of Minnesota, Saint Paul, Minnesota 55108
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Mullins OJ, Friesen WO. The brain matters: effects of descending signals on motor control. J Neurophysiol 2012; 107:2730-41. [PMID: 22378172 DOI: 10.1152/jn.00107.2012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ability of nerve cords and spinal cords to exhibit fictive rhythmic locomotion in the absence of the brain is well-documented in numerous species. Although the brain is important for modulating the fictive motor output, it is broadly assumed that the functional properties of neuronal circuits identified in simplified preparations are conserved with the brain attached. We tested this assumption by examining the properties of a novel interneuron recently identified in the leech (Hirudo verbana) nerve cord. This neuron, cell E21, initiates and drives stereotyped fictive swimming activity in preparations of the isolated leech nerve cord deprived of the head brain. We report that, contrary to expectation, the motor output generated when cell E21 is stimulated in preparations with the brain attached is highly variable. Swim frequency and episode duration are increased in some of these preparations and decreased in others. Cell E21 controls swimming, in part, via excitatory synaptic interactions with cells 204, previously identified gating neurons that reliably initiate and strongly enhance leech swimming activity when the brain is absent. We found that in preparations with the brain present, the magnitude of the synaptic interaction from cell E21 to cell 204 is reduced by 50% and that cell 204-evoked responses also were highly variable. Intriguingly, most of this variability disappeared in semi-intact preparations. We conclude that neuronal circuit properties identified in reduced preparations might be fundamentally altered from those that occur in more physiological conditions.
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Affiliation(s)
- Olivia J Mullins
- Dept. of Biology, Univ. of Virginia, Charlottesville, VA 22904-4328, USA.
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8
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Mullins OJ, Brodfuehrer PD, Jusufović S, Hackett JT, Friesen WO. Specialized brain regions and sensory inputs that control locomotion in leeches. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2011; 198:97-108. [PMID: 22037913 DOI: 10.1007/s00359-011-0691-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 10/11/2011] [Accepted: 10/11/2011] [Indexed: 11/26/2022]
Abstract
Locomotor systems are often controlled by specialized cephalic neurons and undergo modulation by sensory inputs. In many species, dedicated brain regions initiate and maintain behavior and set the duration and frequency of the locomotor episode. In the leech, removing the entire head brain enhances swimming, but the individual roles of its components, the supra- and subesophageal ganglia, in the control of locomotion are unknown. Here we describe the influence of these two structures and that of the tail brain on rhythmic swimming in isolated nerve cord preparations and in nearly intact leeches suspended in an aqueous, "swim-enhancing" environment. We found that, in isolated preparations, swim episode duration and swim burst frequency are greatly increased when the supraesophageal ganglion is removed, but the subesophageal ganglion is intact. The prolonged swim durations observed with the anterior-most ganglion removed were abolished by removal of the tail ganglion. Experiments on the nearly intact leeches show that, in these preparations, the subesophageal ganglion acts to decrease cycle period but, unexpectedly, also decreases swim duration. These results suggest that the supraesophageal ganglion is the primary structure that constrains leech swimming; however, the control of swim duration in the leech is complex, especially in the intact animal.
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Affiliation(s)
- Olivia J Mullins
- Department of Biology, University of Virginia, P.O. Box 400328, Charlottesville, VA 22904-4328, USA
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9
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Lamb DG, Calabrese RL. Neural circuits controlling behavior and autonomic functions in medicinal leeches. NEURAL SYSTEMS & CIRCUITS 2011; 1:13. [PMID: 22329853 PMCID: PMC3278399 DOI: 10.1186/2042-1001-1-13] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 09/28/2011] [Indexed: 12/22/2022]
Abstract
In the study of the neural circuits underlying behavior and autonomic functions, the stereotyped and accessible nervous system of medicinal leeches, Hirudo sp., has been particularly informative. These leeches express well-defined behaviors and autonomic movements which are amenable to investigation at the circuit and neuronal levels. In this review, we discuss some of the best understood of these movements and the circuits which underlie them, focusing on swimming, crawling and heartbeat. We also discuss the rudiments of decision-making: the selection between generally mutually exclusive behaviors at the neuronal level.
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Affiliation(s)
- Damon G Lamb
- Department of Biology, Emory University, 1510 Clifton Road, Atlanta, GA 30322, USA
| | - Ronald L Calabrese
- Department of Biology, Emory University, 1510 Clifton Road, Atlanta, GA 30322, USA
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10
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Blitz DM, Nusbaum MP. Neural circuit flexibility in a small sensorimotor system. Curr Opin Neurobiol 2011; 21:544-52. [PMID: 21689926 DOI: 10.1016/j.conb.2011.05.019] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 05/02/2011] [Accepted: 05/24/2011] [Indexed: 01/06/2023]
Abstract
Neuronal circuits underlying rhythmic behaviors (central pattern generators: CPGs) can generate rhythmic motor output without sensory input. However, sensory input is pivotal for generating behaviorally relevant CPG output. Here we discuss recent work in the decapod crustacean stomatogastric nervous system (STNS) identifying cellular and synaptic mechanisms whereby sensory inputs select particular motor outputs from CPG circuits. This includes several examples in which sensory neurons regulate the impact of descending projection neurons on CPG circuits. This level of analysis is possible in the STNS due to the relatively unique access to identified circuit, projection, and sensory neurons. These studies are also revealing additional degrees of freedom in sensorimotor integration that underlie the extensive flexibility intrinsic to rhythmic motor systems.
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Affiliation(s)
- Dawn M Blitz
- 215 Stemmler Hall, Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, United States
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11
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Mullins OJ, Hackett JT, Buchanan JT, Friesen WO. Neuronal control of swimming behavior: comparison of vertebrate and invertebrate model systems. Prog Neurobiol 2011; 93:244-69. [PMID: 21093529 PMCID: PMC3034781 DOI: 10.1016/j.pneurobio.2010.11.001] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 11/01/2010] [Accepted: 11/08/2010] [Indexed: 01/26/2023]
Abstract
Swimming movements in the leech and lamprey are highly analogous, and lack homology. Thus, similarities in mechanisms must arise from convergent evolution rather than from common ancestry. Despite over 40 years of parallel investigations into this annelid and primitive vertebrate, a close comparison of the approaches and results of this research is lacking. The present review evaluates the neural mechanisms underlying swimming in these two animals and describes the many similarities that provide intriguing examples of convergent evolution. Specifically, we discuss swim initiation, maintenance and termination, isolated nervous system preparations, neural-circuitry, central oscillators, intersegmental coupling, phase lags, cycle periods and sensory feedback. Comparative studies between species highlight mechanisms that optimize behavior and allow us a broader understanding of nervous system function.
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Affiliation(s)
- Olivia J. Mullins
- Dept. of Biology University of Virginia Charlottesville, VA 22904-4328
- Neuroscience Graduate Program University of Virginia Charlottesville, VA 22904-4328
| | - John T. Hackett
- Neuroscience Graduate Program University of Virginia Charlottesville, VA 22904-4328
- Dept. of Molecular Physiology and Biological Physics University of Virginia Charlottesville, VA 22904-4328
| | - James T. Buchanan
- Dept. of Biological Sciences Marquette University Milwaukee, WI 53233
| | - W. Otto Friesen
- Dept. of Biology University of Virginia Charlottesville, VA 22904-4328
- Neuroscience Graduate Program University of Virginia Charlottesville, VA 22904-4328
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