Neuroscience
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Olfactory event-related potentials (OERPs) are widely used to study central odor processing. Only a few studies used this method in children and adolescents. Aim of the current study therefore was to measure OERP and the possible influences of age and sex on central odor processing in this age group. ⋯ OERP can be used to study central odor processing in children older than 6 years of age. Central odor processing changes from childhood to adolescents possibly reflecting maturation of the brain.
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An important challenge in olfaction research is to understand how percepts relate to the molecular structure of stimuli. Previous psychophysical studies showed that, whereas structurally simple odorant molecules evoked a more uniform qualitative perception as revealed by the use of a small number of labels to describe their olfactory quality, more complex odorants evoked a larger variety of olfactory qualities, reflecting a more heterogeneous qualitative perception. The present study examined how this influence of odorant molecular complexity on perception is reflected in the human brain. ⋯ Low- and high-complexity odorants were judged to have the same intensity, pleasantness and familiarity (p>0.05 in all cases), whereas complex odorants induced more quality labels than simple odorants (p<0.02) as expected. Imaging analysis of complex vs. simple odorants revealed significant activation in dorsal anterior cingulate gyrus, but not in primary olfactory areas. Taken together, these findings suggest dissociated neural representations of uniform and heterogeneous olfactory perception, highlighting for the first time the impact of odorant complexity on activity of the cingulate gyrus.
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Hearing function lost by degeneration of inner ear spiral ganglion neurons (SGNs) in the auditory nervous system could potentially be compensated by cellular replacement using suitable donor cells. Donor cell-derived neuronal development with functional synaptic formation with auditory neurons of the cochlear nucleus (CN) in the brainstem is a prerequisite for a successful transplantation. Here a rat auditory brainstem explant culture system was used as a screening platform for donor cells. ⋯ Difference between Y27632- and PD168393-treated HNPCs acquiring neuronal fate was significant, though not different from the fates acquired in control co-culture. Our data suggest the presence of inhibitory mechanisms in the graft-host environment of the auditory brainstem slice co-culture system with neurite growth arresting properties which can be modulated by administration of signaling pathways antagonists. Therefore the co-culture system can be utilized for screens of donor cells and compounds regulating neuronal fate determination.
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The development and maintenance of cocaine addiction depend heavily on learned reward-environment associations that can induce drug-seeking behavior and relapse. Understanding the mechanisms underlying these cue-induced conditioned responses is important for relapse prevention. To test whether intracellular responses measured after cocaine conditioned place preference (CPP) expression are context-dependent, we re-exposed cocaine-treated rats (drug-free) to an environment previously paired with cocaine or saline, 24h after the CPP test. ⋯ Conversely, the higher cocaine dose, independent of environment, resulted in increased NAc FosB, ΔFosB and phosphorylated CREB (pCREB) protein levels compared to those conditioned with 5mg/kg cocaine (non-CPP-expressing). Our results suggest that NAc ERK phosphorylation may be involved with retrieving the contextual information of a cocaine-association, without necessarily motivating the expression of CPP behavior. Additionally, we show distinct patterns of intracellular responses in the NAc and CPu indicating a region-specific role for pERK/pCREB/FosB intracellular signaling in the retrieval of cocaine-context associations.
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Gamma-aminobutyric acid (GABA) is a major inhibitory neurotransmitter of the retina and affects myopic development. Electroacupuncture (EA) is widely utilized to treat myopia in clinical settings. However, there are few reports on whether EA affects the level of retinal GABA during myopic development. ⋯ Moreover, these effects of EA show a positional specificity. While applying EA at a sham acupoint, no apparent change of myopic retinal GABA and its receptor subtypes was observed. Taken together, our findings suggest that LIM is effective to up-regulate the level of retinal GABA, GABAA and GABAC receptors in guinea pigs and the effect may be inhibited by EA stimulation at LI4 and EX-HN5 acupoints.