Manganese enhancement in posterior piriform cortex after unilateral bulbectomy in neonatal SD rats

Theme: Adapting MR in a Changing WorldTraditional Poster Session - Neuro B: Manganese Enhanced MRI (MEMRI): no. 0952The olfactory system plays an important role for survival in rodents and shows robust plasticity after injury. Biological studies have observed regeneration of olfactory axons and synapse formation in the frontal cortex after neonatal unilateral olfactory bulb ablation (OBA). In this study, we aim to investigate how the transneuronal transportation of manganese after OBA would change with time. The results demonstrated that the enhancement in the ipsilateral pPir after OBA decreased at P28 as compared with that at P12, indicating recovery of olfactory function till this time was not very likely, although olfactory neurons would reconstituted within 30 days and form glomeruli-like structures.link_to_OA_fulltextThe 20th Annual Meeting & Exihibition of the International Society of Magnetic Resonance in Medicine (ISMRM 2012), Melbourne, Australia, 5-11 May 2012. In Proceedings of the 20th ISMRM, 2012, no. 095

Metabolic changes in hippocampus and thalamus after sleep deprivation: an experimental proton MRS study

Electronic Poster Session - Neuro A - Animal Models of Brain Disease & Neurovascular: no. 3093 (computer no. 12)Theme: Adapting MR in a Changing WorldIn this study, in vivo 1H MRS was employed to investigate the metabolic changes induced by sleep deprivation (SD) in hippocampus and thalamus of a rat model. Reduced NAA:Cr was found in hippocampus, indicating neuronal loss and cellular dysfunction. The reduction of glutamate observed in hippocampus can reflect reduced cellular excitability. In thalamus, lactate was found to decrease in thalamus after SD, as a result of glucose metabolism decrease. Our finding of Glu:Cr increase in thalamus possibly arises from increased glutamine synthetase. The results of this study provide neurochemical evidence of the behavioral deficits associated with sleep deprivation.link_to_OA_fulltextThe 20th Annual Meeting & Exihibition of the International Society of Magnetic Resonance in Medicine (ISMRM 2012), Melbourne, Australia, 5-11 May 2012. In Proceedings of the 20th ISMRM, 2012, no. 309

DTI detection of microstructural changes induced by sleep deprivation

Theme: Adapting MR in a Changing WorldTraditional Poster Session - Neuro A: Animal Models of Brain Disease Other Than Stroke: no. 0910Rapid eye movement (REM) sleep is believed to be critical for memory consolidation. To probe the microstructural changes after sleep deprivation (SD) in vivo, REM-SD and DTI were employed in this study. Significant axial, radial and mean diffusivity decreases were found bilaterally in various locations in hippocampus, suggesting specific layers of hippocampus such as dentate gyrus and CA1 may be more susceptible to SD. Significant FA, axial and mean diffusivity decreases were also detected in cortex. Our results indicated that DTI is sensitive for probing microstructural changes, and can provide insights into the microstructural plasticity associated with sleep and memory.link_to_OA_fulltextThe 20th Annual Meeting & Exihibition of the International Society of Magnetic Resonance in Medicine (ISMRM 2012), Melbourne, Australia, 5-11 May 2012. In Proceedings of 20th ISMRM, 2012, no. 091

MEMRI reveals neuronal changes in specific hippocampal substructures following sleep deprivation

Theme: Adapting MR in a Changing WorldTraditional Poster Session - Neuro B: Manganese Enhanced MRI (MEMRI): no. 0943Sleep deprivation not only compromises alertness and cognitive performance, but also induces adverse effects in memory and emotional behaviors. In this study, we aim to employ high resolution MEMRI to probe in vivo neuronal changes following sleep deprivation. Significantly reduced Mn uptake was observed in the hippocampal region of the sleep deprived animals. In particular, the dentate gyrus exhibited the least Mn uptake, indicating its functional vulnerability to sleep deprivation.link_to_OA_fulltextThe 20th Annual Meeting & Exihibition of the International Society of Magnetic Resonance in Medicine (ISMRM 2012), Melbourne, Australia, 5-11 May 2012. In Proceedings of the 20th ISMRM, 2012, no. 094

Resting-state functional connectivity changes induced by sleep deprivation

Theme: Adapting MR in a Changing WorldElectronic Poster Session - Neuro A - Psychiatric Disorders: no. 3134 (computer no. 29)Sleep deprivation (SD) is known to diminish alertness and impair cognitive performance in humans. The intrinsic connectivity during resting-state may also be modified by SD. In this study, we used rsfMRI to examine the changes in functional connectivity induced by rapid eye movement SD in rat brains. After SD, interhemispheric correlations in hippocampus prominently diminished, indicating possible neuronal loss or/and neuronal dysfunction. Reduced intercortical connection in visual cortex was also observed, consistent with earlier studies showing decreased neuronal activity in this region after SD.link_to_OA_fulltextThe 20th Annual Meeting & Exihibition of the International Society of Magnetic Resonance in Medicine (ISMRM 2012), Melbourne, Australia, 5-11 May 2012. In Proceedings of the 20th ISMRM, 2012, no. 313

Profiling wallerian degeneration in ipsilateral pyramidal tract after experimental intracerebral hemorrhage

Theme: Adapting MR in a Changing WorldElectronic Poster Session - Neuro A - Animal Models of Brain Disease & Educational: no. 3062 (computer no. 3)Intracerebral hemorrhage (ICH) often produces severe neurological deficits in survivors, which is closely related with secondary corticospinal tract (CST) injury. Rodent models of ICH have greatly promoted the understanding of histopathology underlying brain injury and were employed widely for exploring therapeutic strategies. This study investigated WD in pyramidal tract, as part of CST, after experimental ICH using diffusion tensor imaging (DTI) and T2-weighted imaging as well as with histological correlations. The results demonstrated DTI as a valuable tool for detecting WD in early phase and for longitudinal monitoring of its progress at different stages with more accuracy than T2-weighted imaging.link_to_OA_fulltextThe 20th Annual Meeting & Exihibition of the International Society of Magnetic Resonance in Medicine (ISMRM 2012), Melbourne, Australia, 5-11 May 2012. In Proceedings of the 20th ISMRM, 2012, no. 306

The effect of pretreatment or combined treatment of quercetin on menadione toxicity in rat primary mixed glial cells in vitro

Neurons and glia are highly susceptible to reactive oxygen species that play a key role in various neurodegenerative diseases. Menadione, a synthetic derivative of vitamin K, induces reactive oxygen generation. Quercetin one of the most ubiquitous bioflavonoids in food of plant origin, has strong antioxidant activities on different cell types, however recent studies demonstrated that it has also prooxidant and cytotoxic potentials. We examined the action of pre- and co-treatment of quercetin on menadione induced glial toxicity. The primary mixed glial cells obtained from 1 to 3 day old rat brain were pretreated with 10, 25, 100 or 250 μM quercetin for 1 h, washed out and 10, 25, 50, 75 or 100 μM menadione was added for 6 h. The other group of cells was treated with respective doses of quercetin combined simultaneously with the same doses of menadione for 6 h. The cells were washed and incubated for additional 24 h for recovery period and the viability was measured by using MTT assay. Menadione was dose-dependently toxic to glia cells and pretreatment with respective quercetin doses for 1 h could not eliminate this toxicity. Although 10 and 25 μM quercetin combined with 10 and 25 μM menadione could not change, 100 and 250 μM quercetin together with 10 or 25 μM menadione for 6 h increased further the menadione induced toxicity. We conclude that when combined with menadione, quercetin at high doses could be toxic to primary rat glia cells in culture