The mammal brain can largely reorganize after lesion at peripheral or central level. Several studies focused on the modifications occurring in sensorymotor cortex after central excitotoxic and ischemic lesion in adult rat. In newborn rat the somatotopic organization of motor cortex (M1) go to remodelling both after motor or sensory peripheral disconnection. Remain unknown the effect of central lesion on the development of motor cortex. The aim of this experiment is to study the development of vibrissae motor cortex (VMC) after ischemic lesion of vibrissae barrel cortex (VBC) in newborn rat. Five 7-day-old Wistar rat (P7 group) underwent parietal branch of middle cerebral artery occlusion to induce a small lesion of vibrissae barrel cortex. At P90 rats underwent intracortical microstimulation (ICMS) for mapping VMC ipsilateral to lesioned BFC. Moreover, VMC was investigated in Control (n=5) and Sham group (n=5). Under ketamine anaesthesia (50mg\Kg i.p.) the ICMS (30 ms trains of 0.2 ms cathodal pulses at 300 Hz, stimulation current *60 microA) was delivered at a depth of 1.5mm from the pial surface using glass-insulated tungsten microelectrodes (impedance:0.6-1.2MOhm). ICMS experiments demonstrated that, in the ipsilateral VMC there was a decrease in the size of vibrissa representation compared to Control- and Sham-groups (p<0.05 ANOVA). In all experimental hemispheres the eye movement representation expands in the medial part of the disconnected vibrissae area. The forelimb representation expands in the lateral part of the vibrissa representation. There was a significant increase in the percentage of eye and forelimb sites (p<0.05 ANOVA). The ischemic lesion of the vibrissae barrel cortex in newborn rat induce a large rearrangement of the vibrissae motor cortex in adult life. The development of VMC is strongly dependent from sensory cortico-cortical pathway.
Long-lasting vibrissae motor cortex modifications following vibrissae barrel cortex ischemic lesion in newborn rat
VERONESI, Carlo;
2010
Abstract
The mammal brain can largely reorganize after lesion at peripheral or central level. Several studies focused on the modifications occurring in sensorymotor cortex after central excitotoxic and ischemic lesion in adult rat. In newborn rat the somatotopic organization of motor cortex (M1) go to remodelling both after motor or sensory peripheral disconnection. Remain unknown the effect of central lesion on the development of motor cortex. The aim of this experiment is to study the development of vibrissae motor cortex (VMC) after ischemic lesion of vibrissae barrel cortex (VBC) in newborn rat. Five 7-day-old Wistar rat (P7 group) underwent parietal branch of middle cerebral artery occlusion to induce a small lesion of vibrissae barrel cortex. At P90 rats underwent intracortical microstimulation (ICMS) for mapping VMC ipsilateral to lesioned BFC. Moreover, VMC was investigated in Control (n=5) and Sham group (n=5). Under ketamine anaesthesia (50mg\Kg i.p.) the ICMS (30 ms trains of 0.2 ms cathodal pulses at 300 Hz, stimulation current *60 microA) was delivered at a depth of 1.5mm from the pial surface using glass-insulated tungsten microelectrodes (impedance:0.6-1.2MOhm). ICMS experiments demonstrated that, in the ipsilateral VMC there was a decrease in the size of vibrissa representation compared to Control- and Sham-groups (p<0.05 ANOVA). In all experimental hemispheres the eye movement representation expands in the medial part of the disconnected vibrissae area. The forelimb representation expands in the lateral part of the vibrissa representation. There was a significant increase in the percentage of eye and forelimb sites (p<0.05 ANOVA). The ischemic lesion of the vibrissae barrel cortex in newborn rat induce a large rearrangement of the vibrissae motor cortex in adult life. The development of VMC is strongly dependent from sensory cortico-cortical pathway.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
