Experience-dependent amelioration of motor impairments in adulthood following neonatal medial frontal cortex injury in rats is accompanied by motor map expansion.
One of the most common, and disruptive, neurological symptoms following neonatal brain injury is a motor impairment. Neonatal medial frontal cortical lesions in rats produce enduring motor impairments, and it is thought that lesion-induced abnormal cortical morphology and connectivity may underlie the motor deficits. In order to investigate the functional consequences of the lesion-induced anatomical abnormalities in adulthood, we used intracortical microstimulation to determine the neurophysiologic organization of motor maps within the lesion hemisphere. In addition, groups of neonatal lesion rats were given reach training or complex housing rehabilitation in adulthood and then mapped with intracortical microstimulation. The results demonstrate that neonatal medial frontal cortex lesions produce motor deficits in adulthood that are associated with abnormal motor maps. Further, adult behavioral treatment promoted partial recovery that was supported by reorganization of the motor maps whereby there were increases in the size of the forelimb motor maps. The experience-induced expansion of the forelimb motor maps in adulthood provides a neural mechanism for the experience-dependent improvements in motor performance.
Williams
P T J
PT
Canadian Centre for Behavioural Neuroscience, Department of Psychology and Neuroscience, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, Canada T1K 3M4. preston.williams@uleth.ca
Gharbawie
O A
OA
Kolb
B
B
Kleim
J A
JA
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal / Q000502:physiology / Q000528:radiation effects; D001930:Brain Injuries / Q000150:complications*; D001931:Brain Mapping; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D005552:Forelimb / Q000294:innervation / Q000503:physiopathology; D005625:Frontal Lobe / Q000473:pathology*; D007839:Functional Laterality / Q000502:physiology; D008297:Male; D009069:Movement Disorders / Q000209:etiology* / Q000628:therapy*; D010805:Physical Conditioning, Animal / Q000379:methods*; D011597:Psychomotor Performance / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D012737:Sex Factors; D018709:Statistics, Nonparametric