Motor and Reflexive Behavior in the Aging Rat

Abstract

Four age groups of Fischer 344 rats (6-, 12-, 18-, and 24-months of age) were compared on a battery of reflexive and locomotor tasks. The simple reflexive tasks such as placing, hopping, negative geotaxis and surface and mid-air righting showed little or no change as a function of age. In contrast, tasks requiring more coordinated control of motor and reflexive responses such as suspension from a horizontal wire, descent of a wire mesh pole, traversal of an elevated platform and rotorod performance showed significant declines with age, with some declines noticeable early in the lifespan. When these results are compared with the results of tasks conducted with infant rats, it is noted that the reflexive and motor skills that emerge early in development are the least affected by the aging process. This observation suggests a first-in, last-out sequence for reflexive and motor behaviors.

Functional breakdown of the lipid bilayer of the myelin membrane in central and peripheral nervous system by disrupted galactocerebroside synthesis

“…In the open field test the homozygous cgt Ϫ/Ϫ mutant mouse showed only minute activity. Furthermore, homozygotes were unable to perform the horizontal wire test (22) due to an increasing weakness of their front and hind legs, which were severely paralyzed around day 21. Heterozygous mice showed no neurological symptoms.…”

“…Nerve conduction was measured by proximal stimulation of the sciatic nerve at the knee and distal close to the hip, using a Medelec electromyograph, model MS92. Gait pattern was recorded as described (21,22).…”

Assessment of Motor Balance and Coordination in Mice using the Balance Beam

“…The beam test can detect motor deficits due to age, central nervous syst`lesions, and genetic and pharmacological manipulations in young and older rodents 2,3,4 .…”

Motor uncoordination and neuropathology in a transgenic mouse model of Machado–Joseph disease lacking intranuclear inclusions and ataxin-3 cleavage products

“…In addition, we included the vertical pole test (Wallace et al, 1980), the footprint pattern test (Carter et al, 1999) and the counting of rears over 5 min in the viewing jar as a measure of spontaneous exploratory activity. The protocol was adjusted in order to minimize animal handling and to generate uniformity in waiting times between the tests (Rafael et al, 2000).…”