Understanding the genesis and control of movement is a major goal of neuroscience because of movement's role in behavior and the tragic consequences of diseases that impair movement. Rhythmic patterned movements (e.g., walking) have often been used to investigate these issues because of their importance, ubiquity, inducibility, and stereotypy. We now know that the basic rhythmicity and patterning of almost all such movements arise from the activity of relatively small, endogenously rhythmic central neural networks (central pattern generators) that can continue to cycle in the absence of patterned input. These networks thus not only generate patterned rhythmic movements, but are also simple examples of the nervous system's ability to spontaneously create. Their study thus sheds light not only on movement generation, but possibly also on the mechanisms underlying more complex abilities of nervous systems. Rhythmic neural networks have therefore been extensively studied. This work has revealed that these networks generally contain both complex, non-hierarchical, distributed synaptic connectivity patterns, and neurons with complex, non-linear, active cellular properties. This complexity presumably underlies a third surprising result of this research - these networks produce multiple outputs. This research has dramatically increased our understanding of (and appreciation for) the capabilities of these networks, but we still have relatively little understanding of the mechanisms that give rise to these multiple activity modes, or of their functional consequences (i.e., the motor patterns they produce). A common example of this """"""""multiple activity"""""""" capability is that many of these networks produce phase constant outputs as cycle period is altered (e.g., the network proportionally alters all burst durations and inter-neuronal delays so as to produce the """"""""same"""""""" pattern at all cycle periods). This proposal outlines a combination of neuron and muscle experiments on, and computer simulations of, the well described pyloric neuromuscular system of the lobster, Panulirus interruptus, aimed at elucidating how this system maintains phase. The experimental advantages of this preparation allow all the network's neurons to be individually characterized, and the system to be studied on all levels from membrane conductances to muscle contraction.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Project (R01)
Project #
5R01MH057832-04
Application #
6363698
Study Section
Cognitive Functional Neuroscience Review Committee (CFN)
Program Officer
Glanzman, Dennis L
Project Start
1998-03-10
Project End
2003-02-28
Budget Start
2001-03-01
Budget End
2002-02-28
Support Year
4
Fiscal Year
2001
Total Cost
$144,736
Indirect Cost
Name
Ohio University Athens
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
City
Athens
State
OH
Country
United States
Zip Code
45701
Hooper, Scott L; Buchman, Einat; Weaver, Adam L et al. (2009) Slow conductances could underlie intrinsic phase-maintaining properties of isolated lobster (Panulirus interruptus) pyloric neurons. J Neurosci 29:1834-45
Hobbs, Kevin H; Hooper, Scott L (2009) High-resolution computed tomography of lobster (Panulirus interruptus) stomach. J Morphol 270:1029-41
Thuma, Jeffrey B; White, William E; Hobbs, Kevin H et al. (2009) Pyloric neuron morphology in the stomatogastric ganglion of the lobster, Panulirus interruptus. Brain Behav Evol 73:26-42
Hooper, Scott L; Hobbs, Kevin H; Thuma, Jeffrey B (2008) Invertebrate muscles: thin and thick filament structure;molecular basis of contraction and its regulation, catch and asynchronous muscle. Prog Neurobiol 86:72-127
Hobbs, Kevin H; Hooper, Scott L (2008) Using complicated, wide dynamic range driving to develop models of single neurons in single recording sessions. J Neurophysiol 99:1871-83
Weaver, Adam L; Hooper, Scott L (2003) Follower neurons in lobster (Panulirus interruptus) pyloric network regulate pacemaker period in complementary ways. J Neurophysiol 89:1327-38
Weaver, Adam L; Hooper, Scott L (2003) Relating network synaptic connectivity and network activity in the lobster (Panulirus interruptus) pyloric network. J Neurophysiol 90:2378-86
Hoover, Neil J; Weaver, Adam L; Harness, Patricia I et al. (2002) Combinatorial and cross-fiber averaging transform muscle electrical responses with a large stochastic component into deterministic contractions. J Neurosci 22:1895-904