This application is a competitive renewal to study principles of neural organization and function within motor systems. For this purpose, we have focused on the organization of interneurons and motor neurons mediating escape swimming in the mollusc, Tritonia. During the last grant period, we showed that a single network of interneurons can be organized into different circuits, each of which subserves a different motor function, swimming and reflexive withdrawals.
Our specific aims for the next grant period are: (1) Although substantial portions of the neural circuitry mediating swimming are known, several important elements are missing. Using a combination of anatomical and electrophysiological approaches, we will identify the missing neurons and characterize their synaptic relationships to the known circuitry. (2) This information will be incorporated into a computer model of the swim system and will be used to evaluate the role of specific neural mechanisms in pattern generation. (3) The pattern of synaptic connectivity within the swim system is extremely complex involving many multi-action synapses. Little is known about what transmitters are involved or how they mediate their multiple actions. A combination of cell isolation and electrophysiology will be used to identify putative transmitters and to characterize their mechanisms of action. A new cell isolation technique will be used that allows direct access to receptors on the neuropilar processes. (4) The ability of the swim system to show behavioral plasticity (habituation and sensitization) will be assessed as the first steps towards a long-term study of cellular mechanisms of learning. Electrophysiological experiments are proposed to identify sites of plasticity and to characterize cellular and synaptic mechanisms.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS017328-09
Application #
3397498
Study Section
Physiology Study Section (PHY)
Project Start
1980-09-01
Project End
1990-08-31
Budget Start
1988-09-01
Budget End
1990-08-31
Support Year
9
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of Iowa
Department
Type
Schools of Medicine
DUNS #
041294109
City
Iowa City
State
IA
Country
United States
Zip Code
52242
Brown, G D (1998) Nonassociative learning processes affecting swimming probability in the seaslug Tritonia diomedea: habituation, sensitization and inhibition. Behav Brain Res 95:151-65
Frost, W N; Brown, G D; Getting, P A (1996) Parametric features of habituation of swim cycle number in the marine mollusc tritonia diomedea. Neurobiol Learn Mem 65:125-34
Brown, G D; Frost, W N; Getting, P A (1996) Habituation and iterative enhancement of multiple components of the Tritonia swim response. Behav Neurosci 110:478-85
McClellan, A D; Brown, G D; Getting, P A (1994) Modulation of swimming in Tritonia: excitatory and inhibitory effects of serotonin. J Comp Physiol A 174:257-66
Tourtellotte, W G; Lawrence, D T; Getting, P A et al. (1989) A graphics-oriented personal computer-based microscope charting system for neuroanatomical and neurochemical studies. J Neurosci Methods 29:43-57
Getting, P A (1989) Emerging principles governing the operation of neural networks. Annu Rev Neurosci 12:185-204
McClellan, A D (1988) Functional regeneration of descending brainstem command pathways for locomotion demonstrated in the in vitro lamprey CNS. Brain Res 448:339-45
McClellan, A D (1988) Brainstem command systems for locomotion in the lamprey: localization of descending pathways in the spinal cord. Brain Res 457:338-49
McClellan, A D; Sigvardt, K A (1988) Features of entrainment of spinal pattern generators for locomotor activity in the lamprey spinal cord. J Neurosci 8:133-45
McClellan, A D (1987) In vitro CNS preparations: unique approaches to the study of command and pattern generation systems in motor control. J Neurosci Methods 21:251-64

Showing the most recent 10 out of 11 publications