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Spinal cord injury (SCI) disrupts neuronal networks of ascending and descending tracts at the site of injury, leading to a loss of motor function. Restoration and new circuit formation are important components of the recovery process, which involves collateral sprouting of injured and uninjured fibers. The present study was conducted to determine cortical responses to antidromic stimulation of the corticospinal tracts, to compare changes in the reorganization of neural pathways within normal and spinal cord-injured rats, and to elucidate differences in spatiotemporal activity patterns of the natural progression and reorganization of neural pathways in normal and SCI animals using optical imaging. Optical signals were recorded from the motor cortex in response to electrical stimulation of the ventral horn of the L1 spinal cord. Motor evoked potentials (MEPs) were evaluated to demonstrate endogenous recovery of physiological functions after SCI. A significantly shorter N1 peak latency and broader activation in the MEP optical recordings were observed at 4 weeks after SCI, compared to 1 week after SCI. Spatiotemporal patterns in the cerebral cortex differed depending on functional recovery. In the present study, optical imaging was found to be useful in revealing functional changes and may reflect conditions of reorganization and/or changes in surviving neurons after SCI.

Kura clover (Trifolium ambiguum M. Bieb.) is known to develop an extensive rhizome system when grown in monoculture. However, there is no information about the effects that competition from companion grasses could have on its rhizome development. This study was conducted to determine the difference in rhizome development of kura clover planted in grass, grass plus nitrogen (grass + N) fertilizer, or killed‐grass plots, and to evaluate the effect of defoliation height on kura clover rhizome development. Using 1‐year‐old smooth bromegrass (Bromus inermis Leyss) and Kentucky bluegrass (Poa pratensis L.) swards, experiment 1 and 2 commenced in August 1991 and May 1992, respectively, at the University of Wisconsin Arlington Agricultural Research Station. Ten kura clover entries (populations started from seeds or from rhizomes started from clones) were transplanted into each sub‐plot. Two cutting height sub‐plots were superimposed on each of the three grass sward types. In each Exp., two plants from the same seed or rhizome source represented the experimental unit. Individual plants spread up to 1 m in diameter over a 2‐year period after transplanting when there was no grass competition. For both swards, the mean spread of kura clover by rhizome growth was highest in killed‐grass plots (85 cm diameter), least in the grass + N plots (29 cm diameter) and intermediate (57 cm diameter) in the grass only plots. The defoliation height (4 cm or 10 cm) of the swards did not significantly affect the spread of kura clover regardless of grass status (killed or + or −N) in either smooth bromegrass or Kentucky bluegrass. We conclude that reducing the competition from grasses is a management tool that can be used to maximize the colonizing ability of kura clover.