Abstract
Peripheral afferent denervation induces reorganization of somatotopic maps in primary somatosensory cortex. In the present study, we investigated somatotopic map plasticity after tail amputation using transcranial autofluorescence imaging of mouse cortical activities. Neonatal mice were anesthetized with ether, and the tail was cut at the base. Mice were anesthetized with urethane 8-13 weeks after tail amputation, and the skull were exposed and covered with clear acrylic resin for keeping the transparency of the skull. Cortical images of green autofluorescence in blue light were recorded through the skull. Neural activities in the primary somatosensory cortex were elicited by vibratory stimulation applied to the contralateral hindpaw or tail. In control mice, an activity-dependent autofluorescence increase was observed in the hindpaw; tail base and tail tip regions, which were adjacent to each other in the posterio-medial direction in the somatosensory cortex. In the tail-amputated group, the tail base region shifted toward the region corresponding to the tail tip in control mice. Furthermore, the tail base and hindpaw regions were expanded toward the border between them. Similar results were observed in mice, which received tail amputation at 8 weeks old. These results clearly indicate that somatotopic map was reorganized after tail amputation and the plastic changes were visualized using transcranial autofluorescence imaging of mouse cortical activities. [Jpn J Physiol 55 Suppl:S162 (2005)]
