Cortical origin of functional recovery in the somatosensory cortex of the adult mouse after thalamic lesion.
To study the degree and time course of the functional recovery in the somatosensory cortex (SI) after an excitotoxic lesion in the adult mouse thalamus, metabolic activity was determined in SI at various times points post-lesion. Immediately after the lesion, metabolic activity in the thalamically deafferented part of SI was at its lowest value but increased progressively at subsequent time points. This was seen in all cortical layers; however, layers I and Vb recovered more rapidly than layers II, III, IV, Va and VI. Removal of the mystacial whiskers corresponding to the deafferented area, 5 weeks after cortical recovery, produced a subsequent 32% drop in metabolic activity, demonstrating peripheral sensory activation of this part of the cortex. Tracing experiments revealed that the deafferented cortex did not receive a novel thalamic input but that cortico-cortical and contralateral barrel cortex projections to this area were reinforced. We conclude that the cortical functional recovery after a thalamic lesion is, at least partially, due to modified cortico-cortical and callosal projections to the deafferented cortical area.
Croquelois
Alexandre
A
Département de Biologie Cellulaire et de Morphologie, University of Lausanne, Rue du Bugnon 9, CH-1005 Lausanne, Switzerland. alexandre.croquelois@unil.ch
Bronchti
Gilles
G
Welker
Egbert
E
D000818:Animals; D001345:Autoradiography / Q000379:methods; D001710:Biotin / Q000031:analogs & derivatives* / Q000378:metabolism; D001927:Brain Diseases / Q000503:physiopathology; D001931:Brain Mapping; D003847:Deoxyglucose / Q000493:pharmacokinetics; D003911:Dextrans / Q000378:metabolism; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D051379:Mice; D016571:Neural Networks, Computer; D009434:Neural Pathways / Q000033:anatomy & histology / Q000378:metabolism; D020127:Recovery of Function / Q000502:physiology*; D013003:Somatosensory Cortex / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D013194:Staining and Labeling / Q000379:methods; D013788:Thalamus / Q000293:injuries / Q000502:physiology*; D013997:Time Factors; D014738:Vibrissae / Q000294:innervation / Q000502:physiology
D003911:Dextrans; C076397:biotinylated dextran amine; D001710:Biotin; D003847:Deoxyglucose