Motor pattern selection - sensory and neuromodulatory influences
Final Report Abstract
Handling an overwhelming amount of sensory input and responding adequately to the situation at hand is the most fascinating ability of the nervous system, because it serves to adapt the animal's behavior to the changing requirements of the body and the environment. The flexibility of motor responses often results from a dynamic adaptation of existing motor networks via the actions of neuromodulators that are released from descending pathways originating in higher centers of the nervous system. This project investigates the contribution of descending modulatory neurons to sensorimotor processing, the subsequent selection of adequate motor responses, and the stability of the generated behavior. For this, we are studying the interactions between sensory and modulatory neurons and the representation of proprioceptive and exteroceptive sensory information within the population of modulatory neurons. We are using the well-characterized pattern-generating networks of the stomatogastric nervous system of the crab for our experiments. Sensory, modulatory and motor neurons are available in manageable numbers in this system and intrinsic and synaptic properties have been identified. We find that descending modulation affects the earliest stage of information processing in the nervous system: Action potential initiation and thus information encoding in sensory axons is dependent on modulatory influences, allowing the central nervous system to modulate its own input, making this input task- and state-dependent. On the motor side, neuromodulators elicit distinct behaviors from multifunctional motor circuits. Once these behaviors are active, we find that with in vivo modulatory conditions, behaviors are stabilized by the actions of neuromodulators. Finally, together with our collaborators, we have provided the first de-novo genome sequence of a decapod crustacean. We are currently establishing marbled crayfish as a new genetic model organism. Our data demonstrate that all animals of this parthenogenetic species are clones and genetically identical. We have annotated first neuronal genes of interest and generated primers to quantify modulator actions in identified neurons.
Publications
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(2012) Simultaneous measurement of membrane potential changes in multiple pattern generating neurons using voltage sensitive dye imaging. J. Neurosci. Methods, 203(1): 78-88
Städele, C., Andras, P. & Stein, W.
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(2013) Comparison of Two Voltage-Sensitive Dyes and Their Suitability for Long-Term Imaging of Neuronal Activity. PLoS One. 2013 Oct 4;8(10):e75678
Preuss S. & Stein W.
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(2013) Motor Circuit-Specific Burst Patterns Drive Different Muscle and Behavior Patterns. J. Neurosci., 33(29): 12013-12029
Diehl, F., Stein, W., White, R.S., Stein,W. & Nusbaum, M.P.
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(2014) Optical imaging of neuronal activity and visualization of fine neural structures in non-desheathed nervous systems. PLoS One. 2014 Jul 25;9(7):e103459
Goldsmith, C.J., Städele C. & Stein , W.
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(2014) Phase maintenance in a rhythmic motor pattern during temperature changes in vivo. J. Neurophys., 111(12):2603-2613
Soofi, W., Göritz, M., Kispersky, T.J., Prinz, A.A., Marder, E. & Stein, W.
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(2015) Neuromodulation to the rescue: compensation of temperature-induced breakdown of rhythmic motor patterns via extrinsic neuromodulatory input. PLoS Biology. 13(9):e1002265
Städele C., Heigele, S. & Stein, W.
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(2015) Sources and range of long-term variability of rhythmic motor patterns in vivo. .J Exp Biol. 218, 3950-3961
Yarger, A.M. & Stein W.
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(2016) The Site of Spontaneous Ectopic Spike Initiation Facilitates Signal Integration in a Sensory Neuron. J Neurosci. 36(25): 6718-6731
Städele, C. & Stein, W.
