Articles in 2011

Immediate early genes are rapidly transcribed in response to neuronal activity, but the underlying mechanism is unclear. The authors show that this rapid transcription is mediated by a stalled RNA polymerase II, poised just downstream of the transcription start site. RNAi-depletion of negative elongation factor compromises the rapid transcription.

This paper demonstrates that orientation maps, as found in the cortex of higher mammals, are likely to arise from the spatial layout of retinal ganglion cell receptive fields in the retina. The predictions of this model are borne out in four different species.

The mammalian cochlea can detect near-threshold sound signals by mechanically amplifying sub-nanometer vibrations of the basilar membrane. This study describes vibration enhancement in the hearing organ opposite the basilar membrane, at the reticular lamina.

SK2-containing channels are expressed on dendritic spines of mouse CA1 pyramidal neurons and influence synaptic responses, plasticity and learning. Allen et al. find that the long isoform of SK2 directs synaptic SK2-containing channel expression, mediating synaptic and behavioral effects.

Johnson and colleagues investigate spiking activity in developing inner hair cells (IHCs), showing that apical IHCs fire spontaneous action potentials in a burst-like pattern, whereas basal IHCs fire randomly. The burst-like firing of apical IHCs depends on acetylcholine. Extracellular ATP affects the resting potential of IHCs by activating SK2 channels.

The divisive normalization model has been influential in understanding the response properties of neurons in the visual system. Here the authors show that this computational framework can also provide a simple unifying account of the key features of multisensory integration by neurons, a research area that has traditionally been characterized by empirical principles.

Perceptual learning typically improves discrimination thresholds. Here the authors find that aversive learning actually increased discrimination thresholds, resulting in stimulus generalization. The authors suggest that less specificity could be a benefit in this kind of situation, as it could speed responses in dangerous situations.

This study uses magnetoencephalography to identify neural oscillations associated with the propagation of top-down, predictive information and bottom-up error information.

When making a decision, we have to take into account not only the information that is available, but also the reliability of this information. This behavioral study finds that, while searching for a visual target, people weigh up cue reliability in an almost identical fashion to a mathematical ideal observer, and a neural network model can explain how this behavior is produced.

Using a mouse model of Alzheimer's disease and in vivo microdialysis, this study shows that neuronal activity drives the level of interstitial fluid amyloid-β and subsequent amyloid-β plaque deposition.

Neuroligins are important for synaptogenesis and are thought to influence postsynaptic assembly via binding to PSD-95. In rat organotypic hippocampal slices treated to reduce endogenous neuroligin, the authors find that the C-terminal tail of neuroligin is critical for its function.

The authors show that NMDA receptor activation induces a rapid protein phosphatase 1–dependent dephosphorylation and downregulation of the neuron-specific potassium-chloride co-transporter KCC2. Deficits in KCC2 activity have been observed in disease states associated with pathophysiological glutamate release. Blocking dephosphorylation reduces the glutamate-induced degradation of KCC2 and maintains hyperpolarizing GABAergic inhibition.

Calcium-activated chloride currents are thought to amplify the olfactory signal during the transduction process. Here the authors identify Ano2 as the critical channel in both main olfactory epithelium and in the vomeronasal organ. Surprisingly, disruption of Ano2 did not reduce performance in an olfactory behavioral task, suggesting that olfaction does not actually depend on these channels.

The authors find that the gustatory pheromone detection system in Drosophila can control male-male aggression and that it acts independently of the olfactory pheromone detection system to modulate both aggression and courtship behaviors.

CaMKII phosphorylates the GluA1 AMPA subunit at Ser831 to increase single channel conductance. Here, the authors show that coexpression of TARPs is required for phospho-Ser831 to increase conductance of GluA1/GluA2 receptors. Ser831 phosphorylation increases the efficiency with which each subunit can activate, increasing the likelihood of simultaneous subunit activation during gating.

The authors report that Reelin, the Rap1 GTPase, and N-cadherin are important for multipolar neurons to polarize their migration towards the cortical plate. Their data suggest that Reelin activates Rap1, which in turn upregulates N-cadherin, which is essential for orienting cell migration.

Kisspeptin-releasing neurons, affecting gonadotropin releasing hormone secretion, are thought to coordinate puberty onset. The authors generated mice lacking kisspeptin-expressing cells and found that puberty onset in female mice was unaffected. These animals were also fertile, despite having smaller ovaries.

This study presents a new assay for investigating alcohol reward in Drosophila. Flies learned to associate cues with ethanol intoxication and developed a long-lasting attraction for the ethanol-paired cue. Dopamine neurons were necessary for expression of this conditioned preference. Mutations in a regulator of Notch signaling disrupted the formation of this memory.

The use of brain machine interfaces for neuroprosthetic control is known to change the tuning properties of neurons directly projecting the interface. Here the authors report that there are also tuning changes to indirectly projecting neurons, which are stable, but relatively small when compared with changes in the directly projecting neurons.

Midbrain dopaminergic neuron activity is associated with reward signaling and aversive stimuli. Using genetic models in which excitatory response of dopaminergic neurons are reduced, the authors find that the imbalance of dopaminergic neuronal response following aversive stimuli is manifested in generalized anxiety.