Forelimb Use Restriction Experiment
Objective: To investigate whether lesion-induced asymmetries in motor behavior contribute to dendritic arborization changes by restricting ipsilateral forelimb movement during the dendritic overgrowth period using one-holed vests
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Materials1
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Protocol Steps
Perform unilateral cortical lesion
Create unilateral damage to the forelimb representation area of the sensorimotor cortex in adult rats
Note: This lesion precedes the behavioral restriction phase
View evidence from paper
“Unilateral damage to the forelimb representation area of the sensorimotor cortex in adult rats”
Identify dendritic overgrowth period
Monitor dendritic arborization to identify the period of maximum overgrowth, which occurs at approximately 18 days post-lesion
Note: Arbor size is maximum at approximately 18 days postlesion, followed by partial elimination or pruning
View evidence from paper
“Arbor size was maximum at approximately 18 d postlesion, following which there was a partial elimination, or pruning, of dendritic processes”
Apply one-holed vest restriction
Restrict movements of the forelimb ipsilateral to the lesion by fitting animals with one-holed vests during the dendritic overgrowth period
Note: This intervention interferes with the increase in dendritic arborization
View evidence from paper
“movements of the forelimb ipsilateral to the lesion were restricted during the period of dendritic overgrowth through the use of one-holed vests. This interfered with the increase in dendritic arborization”
Assess dendritic arborization changes
Measure dendritic arborization of layer V pyramidal neurons of the contralateral homotopic cortex to determine if restriction prevented expected increases
Note: Compare results to control groups: animals allowed to use both forelimbs, animals using only ipsilateral forelimb, and sham-operated rats forced to use only one forelimb
View evidence from paper
“In contrast, animals that were allowed to use both forelimbs, or only the forelimb ipsilateral to the lesion, showed the expected increases”
Evaluate sensorimotor function
Assess sensorimotor impairments in animals where dendritic growth was blocked compared to controls
Note: Greater sensorimotor impairments were found when dendritic growth was blocked
View evidence from paper
“greater sensorimotor impairments were found when the dendritic growth was blocked”
Perform pruning period immobilization experiment
In a second experiment, immobilize the impaired limb during the pruning period to determine if prevention of symmetrical forelimb use affects dendritic pruning
Note: Immobilization of the impaired limb during pruning period did not prevent elimination of processes
View evidence from paper
“in a second experiment, immobilization of the impaired limb during the pruning period did not prevent the elimination of processes”