In vivo 3D MRI of insect brain:: cerebral development during metamorphosis of Manduca sexta

High-resolution 3D MRI of male pupae of Manduca sexta was performed at 2.35 T in order to evaluate its potential for an in vivo characterization of insect brain during metamorphosis. T1-weighted 3D FLASH (TR/TE = 20/7.8 ms, 25degrees flip angle) and T2-weighted 3D fast SE MRI data sets (TR/TEeff = 3000/100 ms) were acquired at different developmental stages with an isotropic resolution of 100 mum. Both T1- and T2-weighted 3D MRI allowed for the identification of cerebral structures such as the antermal nerve, antennal and optical lobe, and central brain. Pronounced developmental alterations of the morphology were observed during metamorphosis. The results demonstrate the feasibilitv of 3D MRI at nanoliter resolution to identifv major brain systems of M. sarta and respective changes during pupal development from caterpillar to sphinx moth. Together with the use of suitable contrast agents, this approach may provide new ways for studying the axonal connectivity and neural function of the developing insect brain. (C) 2004 Elsevier Inc. All rights reserved.