The overall goal of the proposed research is to examine how reflex inputs, common drive and recurrent inhibition interact to coordinate motor nuclei. Our approach is 'bottom-up', working from basic physiology rather than proving a preferred model. The first question is how Ia EPSPs and recurrent IPSPs interact in motoneuron dendritic trees. Changes in impedance can be used to estimate the electrotonic position of active synapses. Nonlinear summation of IPSPs and EPSPs will be compared to model predictions. Another issue is how ensemble motor unit activity reflects common drive (stretch or fictive locomotion). Spectral analysis will be used to examine relations between drive and rectified neurogram, or motoneuron PSPs when a Na+ blocker is used to prevent spike firings. A last project is to build a computer model of a two-muscle joint with recurrent inhibition and beta innervation. Published data suggests that the two phenomena may not appear together in distal motor nuclei. The model will be used to explore possible interactions, beneficial and not, of the two spinal circuits.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32NS010341-02
Application #
2546426
Study Section
Neurology B Subcommittee 2 (NEUB)
Program Officer
Heetderks, William J
Project Start
1997-09-30
Project End
Budget Start
1997-09-30
Budget End
1998-09-29
Support Year
2
Fiscal Year
1997
Total Cost
Indirect Cost
Name
St. Joseph's Hospital and Medical Center
Department
Type
DUNS #
131606022
City
Phoenix
State
AZ
Country
United States
Zip Code
85013