Abstract
The central pattern generator for heartbeat in the medicinal leech, Hirudo generates rhythmic activity conveyed by heart excitor motor neurons in segments 3–18 to coordinate the bilateral tubular hearts and side vessels. We focus on behavior and the influence of previously un-described peripheral nerve circuitry. Extracellular recordings from the valve junction (VJ) where afferent vessels join the heart tube were combined with optical recording of contractions. Action potential bursts at VJs occurred in advance of heart tube and afferent vessel contractions. Transections of nerves were performed to reduce the output of the central pattern generator reaching the heart tube. Muscle contractions persisted but with a less regular rhythm despite normal central pattern generator rhythmicity. With no connections between the central pattern generator and heart tube, a much slower rhythm became manifest. Heart excitor neuron recordings showed that peripheral activity might contribute to the disruption of centrally entrained contractions. In the model presented, peripheral activity would normally modify the activity actually reaching the muscle. We also propose that the fundamental efferent unit is not a single heart excitor neuron, but rather is a functionally defined unit of about three adjacent motor neurons and the peripheral assembly of coupled peripheral oscillators.
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Abbreviations
- AV:
-
Afferent vessel
- ANR:
-
Anterior nerve root
- CPG:
-
Central pattern generator
- FMRFamide:
-
Phenylalanine-methionine-arginine-phenylalanine-NH2
- HE:
-
Heart excitor
- HT:
-
Heart tube
- IPSP:
-
Inhibitory post-synaptic potential
- Lav:
-
Latero-abdominal vessel
- Ldv:
-
Latero-dorsal vessel
- Llv:
-
Latero-lateral vessel
- M:
-
Midbody segment
- VJ:
-
Valve junction
References
Arbas EA, Calabrese RL (1990) Leydig neuron activity modulates heartbeat in the medicinal leech. J Comp Physiol A 167:665–671
Brezina V, Orekhova IV, Weiss KR (2000) The neuromuscular transform: the dynamic, nonlinear link between motor neuron firing patterns and muscle contraction in rhythmic behaviors. J Neurophysiol 83:207–231
Calabrese RL, Maranto AR (1984) Neural control of the hearts in the leech, Hirudo medicinalis. III. Regulation of myogenicity and muscle tension by heart accessory neurons. J Comp Physiol A 154:393–406
Calabrese RL, Maranto AR (1986) Cholinergic action on the heart of the leech, Hirudo medicinalis. J Exp Biol 125:205–224
Calabrese RL, Norris BJ, Wenning A, Wright TM (2011) Coping with variability in small neuronal networks. Integr Comp Biol. doi:10.1093/icb/icr074
Cang J, Friesen WO (2000) Sensory modification of leech swimming: rhythmic activity of ventral stretch receptors can change intersegmental phase relationships. J Neurosci 20:7822–7829
Cang J, Friesen WO (2002) Model for intersegmental coordination of leech swimming: central and sensory mechanisms. J Neurophysiol 87:2760–2769
Chen J, Iwasaki T, Friesen WO (2011) Mechanisms underlying rhythmic locomotion: dynamics of muscle activation. J Exp Biol 214:1955–1964
Cohen AH, Wallen P (1980) The neuronal correlate of locomotion in fish: “fictive swimming” induced in an in vitro preparation of the lamprey spinal cord. Exp Brain Res 41:11–18
Delcomyn F (1980) Neural basis of rhythmic behavior in animals. Science 210:492–498
Deller SRT, MacMillan DL (1989) Entrainment of the swimmeret rhythm of the crayfish to controlled movements of some of the appendages. J Exp Biol 144:257–278
Dickinson PS, Nagy F, Moulins M (1988) Control of central pattern generators by an identified neurone in crustacean: activation of the gastric mill motor pattern by a neurone known to modulate the pyloric network. J Exp Biol 136:53–87
Garcia PS, Wright TM, Cunningham IR, Calabrese RL (2008) Using a model to assess the role of the spatiotemporal pattern of inhibitory input and intrasegmental electrical coupling in the intersegmental and side-to-side coordination of motor neurons by the leech heartbeat central pattern generator. J Neurophysiol 100:1354–1371
Goaillard JM, Taylor AL, Schulz DJ, Marder E (2009) Functional consequences of animal-to-animal variation in circuit parameters. Nat Neurosci 12:1424–1430
Grillner S, Parker D, Manira AE (1998) Vertebrate locomotion—a lamprey perspective. NY Acad Sci 860:1–18
Hammersen F, Staudte H-W, Möhring E (1976) Studies of the fine structure of invertebrate blood vessels. II. The valves of the lateral sinus of the leech Hirudo medicinalis L. Cell Tissue Res 172:405–423
Harik TM, Attaman J, Crowley A, Jellies J (1999) Developmentally regulated target-associated cues influence axon sprouting and outgrowth and may contribute to target specificity. Dev Biol 212:351–365
Heitler WJ (1986) Aspects of sensory integration in the crayfish swimmeret system. J Exp Biol 120:387–402
Hildebrandt JP (1988) Circulation in the leech, Hirudo medicinalis L. J Exp Biol 134:235–246
Hughes GM, Wiersma CAG (1960) The co-ordination of swimmeret movements in the crayfish, Procambarus clarkii (Girard). J Exp Biol 37:656–672
Ikeda K, Wiersma CAG (1964) Autogenic rhythmicity in the abdominal ganglia of the crayfish: the control of swimmeret movements. Comp Biochem Physiol 12:107–115
Jellies JA (1995) Cellular interactions in the development of Annelid neuromuscular systems. Am Zool 35:529–541
Jellies J, Kopp DM (1995) Sprouting and connectivity of embryonic leech heart excitor (HE) motor neurons in the absence of their peripheral target. Invert Neurosci 1:145–157
Jellies J, Kopp DM, Bledsoe JW (1992) Development of segment- and target-related neuronal identity in the medicinal leech. J Exp Biol 170:71–92
Jellies J, Kopp DM, Johansen K, Johansen J (1996) Initial formation and secondary condensation of nerve pathways in the medicinal leech. J Comp Neurol 373:1–10
Kiehn O, Butt SJB (2003) Physiological, anatomical and genetic identification of CPG neurons in the developing mammalian spinal cord. Prog Neurobiol 70:347–361
Krahl B, Zerbst-Boroffka I (1983) Blood pressure in the leech Hirudo medicinalis. J Exp Biol 107:163–168
Kristan WB, Calabrese RL (1976) Rhythmic swimming activity in neurons of the isolated nerve cord of the leech. J Exp Biol 65:643–668
Kueh D, Jellies JA (2012) Targeting of a neuropeptide to discrete regions of the motor arborizations of a single neuron. J Exp Biol (in press)
Kuhlman JR, Li C, Calabrese RL (1985a) FMRF-amide-like substances in the leech. I. Immunocytochemical localization. J Neurosci 5:2301–2309
Kuhlman JR, Li C, Calabrese RL (1985b) FMRF-amide-like substances in the leech. II. Bioactivity on the heartbeat system. J Neurosci 5:2310–2317
Li C, Calabrese RL (1987) FMRF-amide-like substances in the leech. III. Biochemical characterization and physiological effects. J Neurosci 7:595–603
Lund JP (2011) Chew before you swallow. In: Gossard JP, Dubuc R, Kolta A (eds) Progress in brain research. Breathe, walk and chew the neural challenge: Part II. Elsevier, Amsterdam, pp 219–251
Maranto AR, Calabrese RL (1984a) Neural control of the hearts in the leech Hirudo medicinalis. I. Anatomy, electrical coupling, and innervation of the hearts. J Comp Physiol A 154:367–380
Maranto AR, Calabrese RL (1984b) Neural control of the hearts in the leech, Hirudo medicinalis. II. Myogenic activity and its control by heart motor neurons. J Comp Physiol A 154:381–391
Marder E, Calabrese RL (1996) Principles of rhythmic motor pattern generation. Physiol Rev 76:687–717
Marzullo TC, Gage GJ (2012) The SpikerBox: a low cost, open-source bioamplifier for increasing public participation in neuroscience inquiry. PLoS ONE 7:e30837
Morgan PT, Perrins R, Lloyd PE, Weiss KR (2000) Intrinsic and extrinsic modulation of a single central pattern generating circuit. J Neurophysiol 84:1186–1193
Muller KJ, Nicholls JG, Stent GS (eds) (1981) Neurobiology of the leech. Cold Spring Harbor, NY
Norris BJ, Weaver AL, Morris LG, Wenning A, Garcia PA, Calabrese RL (2006) A central pattern generator producing alternative outputs: temporal pattern of premotor activity. J Neurophysiol 96:309–326
Norris BJ, Weaver AL, Wenning A, Garcia PS, Calabrese RL (2007a) A central pattern generator producing alternative outputs: pattern, strength, and dynamics of premotor synaptic input to leech heart motor neurons. J Neurophysiol 98:2992–3005
Norris BJ, Weaver AL, Wenning A, Garcia PS, Calabrese RL (2007b) A central pattern generator producing alternative outputs: phase relations of leech heart motor neurons with respect to premotor synaptic input. J Neurophysiol 98:2983–2991
Norris BJ, Baquet G, Weaver AL, Morris LG, Wenning A, Garcia PA, Calabrese AL (2009) A central pattern generator producing alternative outputs: Temporal pattern of premotor activity. J Neurophysiol 96:309–326. doi:10.1152/jn.00011.2006
Norris BJ, Wenning A, Wright TM, Calabrese RL (2011) Constancy and variability in the output of a central pattern generator. J Neurosci 31:4663–4674
Nusbaum MP, Beenhakker MP (2002) A small systems approach to motor pattern generation. Nature 417:343–350
Pickard RS, Mill PJ (1974) Ventilatory movements of the abdomen and branchial apparatus in dragonfly larvae (Odonata: Anisoptera). J Zool 174:23–40
Rybak IA, Shevtsova NA, Lafreniere-Roula M, McCrea DA (2006) Modelling spinal circuitry involved in locomotor pattern generation: insights from deletions during fictive locomotion. J Physiol 577(2):617–639
Saideman SR, Blitz DM, Nusbaum MP (2007) Convergent motor patterns from divergent circuits. J Neurosci 27:6664–6674
Siddall ME, Tronrelj P, Utevsky SY, Nkamany M, Macdonald KS III (2007) Diverse molecular data demonstrate that commercially available medicinal leeches are not all Hirudo medicinalis. Proc Roy Soc B. doi:10.1098/rspb.2007.0248
Smarandache C, Hall WM, Mulloney B (2009) Coordination of rhythmic activity by gradients of synaptic strength in a neural circuit that couples modular neural oscillators. J Neurosci 29:9351–9360
Stein PSG, Grillner S, Selverston AI, Stuart DG (1997) Neurons, networks, and behavior. MIT Press, Cambridge
Stent GS, Kristan WB, Friesen WO, Ort CA, Poon M, Calabrese RL (1978) Neuronal generation of the leech swimming movement. Science 200:1348–1357
Thirumalai V, Marder E (2002) Colocalized neuropeptides activate a central pattern generator by acting on different circuit targets. J Neurosci 22:1874–1882
Thompson WJ, Stent GS (1976a) Neuronal control of heartbeat in the medicinal leech. I. Generation of the vascular constriction rhythm by heart motor neurons. J Comp Physiol 111:261–279
Thompson WJ, Stent GS (1976b) Neuronal control of heartbeat in the medicinal leech. II. Intersegmental coordination of heart motor neuron activity by heart interneurons. J Comp Physiol 111:281–307
Thompson WJ, Stent GS (1976c) Neuronal control of heartbeat in the medicinal leech. III. Synaptic relations of the heart interneurons. J Comp Physiol 111:309–333
Wagenaar DA, Hamilton MS, Huang T, Kristan WB, French KA (2010) A hormone-activated central pattern generator for courtship. Curr Biol 20:487–495
Weeks JC (1981) Neuronal basis of leech swimming: separation of swim initiation, pattern generation, and intersegmental coordination by selective lesion. J Neurophysiol 45:698–723
Wenning A, Meyer EP (2007) Hemodynamics in the leech: blood flow in two hearts switching between two constriction patterns. J Exp Biol 210:2627–2636
Wenning A, Cymbalyuk GS, Calabrese RL (2004a) Heartbeat control in leeches. I. Constriction pattern and neural modulation of blood pressure in intact animals. J Neurophysiol 91:382–396
Wenning A, Hill AAV, Calabrese RL (2004b) Heartbeat control in leeches. II. Fictive motor pattern. J Neurophysiol 91:397–409
Acknowledgments
This work was funded in part by a Faculty Research and Creative Activities Award from Western Michigan University (J.J.) and a National Science Foundation REU award # DBI-1062883. We gratefully acknowledge the assistance of Michelle Alfert in helping gather and analyze preliminary data in intact animals and Wesley J. Thompson for his thoughtful insights on the data reported in this manuscript.
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Jellies, J., Kueh, D. Centrally patterned rhythmic activity integrated by a peripheral circuit linking multiple oscillators. J Comp Physiol A 198, 567–582 (2012). https://doi.org/10.1007/s00359-012-0730-5
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DOI: https://doi.org/10.1007/s00359-012-0730-5