Comparison of single-shot nebuliser protocol between dexmedetomidine and ketamine in children undergoing magnetic resonance imaging.

Background: Sedation for magnetic resonance imaging mandates deep sedation to ensure patient immobility. The nebulised route of drug delivery carries the advantage of good bioavailability and safety profile. We aimed to compare the efficacy and safety of nebulised dexmedetomidine and ketamine for sedation in children undergoing magnetic resonance imaging.

Copying and evolution of neuronal topology.

We propose a mechanism for copying of neuronal networks that is of considerable interest for neuroscience for it suggests a neuronal basis for causal inference, function copying, and natural selection within the human brain. To date, no model of neuronal topology copying exists. We present three increasingly sophisticated mechanisms to demonstrate how topographic map formation coupled with Spike-Time Dependent Plasticity (STDP) can copy neuronal topology motifs.

Differential amplification of intron-containing transcripts reveals long term potentiation-associated up-regulation of specific Pde10A phosphodiesterase splice variants.

We employed differential display of expressed mRNAs (Liang, P., and Pardee, A. B.

Dehydroepiandrosterone (DHEA) stimulates neurogenesis in the hippocampus of the rat, promotes survival of newly formed neurons and prevents corticosterone-induced suppression.

Treating adult male rats with subcutaneous pellets of dehydroepiandrosterone (DHEA) increased the number of newly formed cells in the dentate gyrus of the hippocampus, and also antagonized the suppressive of corticosterone (40 mg/kg body weight daily for 5 days). Neither pregnenolone (40 mg/kg/day), a precursor of DHEA, nor androstenediol (40 mg/kg/day), a major metabolite, replicated the effect of DHEA (40 mg/kg/day). Corticosterone reduced the number of cells labelled with a marker for neurons (NeuN) following a 28-day survival period, and this was also prevented by DHEA.