Fasting-induced Neural Activities Detected By Manganese-enhanced Magnetic Resonance Imaging(MRI) In Mice/Construction Of Anatomical MRI Templates Of Tree Shrew Brain

This thesis is composed two independent parts. In Part I, neural activities in fasted Kuming (KM) mice were measured with manganese enhanced magnetic resonance imaging (MEMRI). Part II describes the construction of anatomical magnetic resonance image templates of tree shrew (Tupaia belangeri chinensis) brain, and volumetric measurement of representative anatomical structures.Food intake is a physiological activity which requires complex yet delicate coordination of the different parts of the central nervous system. In the work described in Part I of this thesis, we set out to measure accumulative neural activities in KM mice during a24-hour fasting period using MEMRI. The animals were given by intraperitoneal injection of MnCl2solution before the removal of food. T1-weighted images of the whole brain were acquired24hours after MnCl2injection. Compared to the non-fasted animals, the fasted animals showed increased neural activities in the insular cortex, cingulate cortex, somatosensory cortex, motor cortex and cerebellum; while many structures in the middle brain (i.e., thalamus, pretectal nucleus, visual and auditory cortex) showed deactivation. Activation of the limbic structure probably for one thing indicates that hunger might cause the brain to launch the so-called danger-monitoring mode and for the other thing might display the desire for food. Meanwhile deactivation of middle brain structures may be related to preferentially reduced physiological functions in these region due to restricted supply of energy substrate—glucose.The tree shrews are special relatives of primates, whose CNS is well-developed and possesses many homologies with that of primates. Tree shrews are increasingly used in neuroscience research. However, the neuroimage data on tree shrew are scarce in the literature, in comparison to those of human and rodents. In the work described in Part II of this thesis, high-resolution anatomical magnetic resonance images and diffusion tensor images of tree shrew brain were acquired in vivo and ex vivo. A set of population-based image templates of tree shrew brain was constructed, all in a reference space. Grey matter/white matter/cerebrospinal fluid probability maps were generated at an isotropic resolution of0.12mm×0.12mm×0.12mm. Masks of representative anatomical structures, such as hippocampus and amygdala were generated in the reference space. Also the volumes of hippocampus and amygdala were measured The magnetic resonance image templates of tree shrew brain generated are useful for statistical parametric analysis/volumetric analysis of neuroimage data of tree shrew brain.