Research articles

Persistent activity can mediate working memory during behavior. Here, the authors report persistent activity during sleep, occurring spontaneously in medial entorhinal cortex layer III (MECIII) neurons' membrane potential. This persistent activity excited hippocampal CA1 neurons. Thus, persistent activity in MECIII contributes to cortico-hippocampal interaction, which could serve several important mnemonic functions.

The authors selectively target a population of hippocampal interneurons called oriens lacunosum-moleculare (OLM) cells with the Chrna2 promoter to demonstrate that these cells differentially modulate CA3 and entorhinal inputs to CA1 pyramidal cells. They also find that OLM cells receive fast cholinergic inputs, providing a plausible explanation for how nicotine affects hippocampal plasticity.

Moving objects generate motion information at different scales, but it is not known how the brain pools all of this information to reconstruct object speed and whether pooling depends on the purpose for which the information will be used. Here the authors find task-dependent differences in pooling that can be explained by an adaptive gain control mechanism.

In this study, the authors compare the RNA binding patterns of FUS/TLS and TDP-43. Although these proteins regulate the processing of mostly distinct gene products, they do show concurrent regulation of a subset of neuronal transcripts that all have exceptionally long introns.

The authors previously showed that a minority of nucleus accumbens neurons, which show strong cocaine-induced activation of the immediate early gene Fos, are necessary for cocaine-induced psychomotor sensitization. Here they find that these cocaine-activated neurons have increased numbers of silent synapses following cocaine sensitization.

The authors show, for human observers, that glossy surfaces can generate both bright specular highlights and dark specular 'lowlights' and that the presence of either is sufficient to generate compelling percepts of gloss. These results suggest that the image structure generated by specular highlights and lowlights is used to construct our experience of surface gloss.

The authors attempt to improve existing retinal models by incorporating measurements of the physiological properties and connectivity of only the primary excitatory circuitry of the retina. The resulting model predicts ganglion cell responses to a variety of spatial patterns and provides a direct correspondence between circuit connectivity and retinal output.

Excitatory connections in cortex are clustered into groups of highly connected neurons. Here the authors examine the effect this clustering has on the dynamics of neuronal networks with balanced excitation and inhibition. Their model suggests that the reported variability in spontaneous and evoked spiking activity may result from clustered cortical architecture.

This study shows that a mouse's trial-and-error learning in the Morris water maze is mediated by a stereotyped sequence of hippocampus activation along its ventral-to-dorsal axis. Using anatomical or molecular lesions and a previously validated morphological readout of mossy fiber circuit refinement, the authors show that the ventral hippocampus in mice has an early role in goal-oriented learning and searching.

This paper reports that there are substantial differences in DNA methylation patterns between nurses and forager caste phenotypes in honeybees, and that reverting foragers back to nurses reestablishes methylation levels for a majority of genes.

Path integration allows animals to track their body position in planar space by relying on both external cues and internal cues. For monitoring internal cues, head direction cells in the anterodorsal thalamic nucleus are one of the best candidates for the neural mechanism underlying path integration. This study shows that head-direction cells in rats act as a mediator of path integration such that their firing matches the level of movement trajectory heading errors in a cumulative manner, and that head-direction cells correct their firing when internal error is corrected by external cues.

Here the authors test the proposal that premotor circuits participate in sensory learning for imitation using convergent approaches in the juvenile zebra finch, including optogenetic disruption and in vivo multiphoton imaging. Their findings provide evidence that premotor circuits help to encode sensory information prior to shaping and executing imitative behaviors.

This work shows that ephrin-B2 from astrocytes provides a critical niche signal for cell fate determination in adult mouse hippocampus, in part by directing neuronal differentiation of adult neural stem cells through EphB4-dependent juxtacrine signaling.

Neurons in the parietal cortex have been shown to encode position in external reference frames. This work demonstrates that parietal cortex neurons can simultaneously register spatial information in multiple external reference frames. The form this takes suggests a mechanism for encoding relationships between parts and the whole that they compose.

Noise-induced sensorineural hearing loss selectively worsens peripheral temporal coding in noisy compared with quiet conditions reports this study in chinchillas. This may explain why noisy conditions are particularly difficult for hearing-impaired people.

Dentate mossy cells in hippocampal slice can temporarily store stimulus information from the perforant path with persistent up-state–like activity. Here, Hyde and Strowbridge show that hippocampal dentate hilar cells can store several distinct patterns of information simultaneously for several seconds and that the activity of the local network in the dentate gyrus can predict which input conveyed the stimulus information and what temporal sequence of stimuli was presented.

Expression of GluN2 subunit of NMDA receptor (NMDAR) in rodents is developmentally regulated such that GluN2B expression is high during early postnatal period but is replaced by GluN2A in adulthood, thus conferring different NMDAR channel properties and kinetics. This study identifies a molecular mechanism for GluN2A/B switch that is mediated by the transcriptional repressor REST. This process is also shown to be affected by postnatal stress induced by maternal deprivation, leading to long-lasting effects on NMDAR-subunit composition in the hippocampus.

Alcoholism and post-traumatic stress disorder are frequently co-morbid. The authors show that chronic intermittent exposure to ethanol impairs extinction of fear conditioning in mice. In vivo recordings showed that extinction encoding was impaired in infralimbic medial prefrontal cortical (mPFC) neurons, which are associated with downregulation of the NMDA receptor subunit GluN1 in mPFC.

Optogenetic manipulations of behavior in primates have largely been unsuccessful. Here, the authors report that monkeys reliably shift their gaze toward the receptive field of optically driven channelrhodopsin-2–expressing V1 neurons.

The authors report that, during sleep, a task-related auditory cue biases hippocampal reactivation events towards replaying the spatial memory associated with that cue. These results indicate that sleep replay can be manipulated by external stimulation, and provide further evidence for the role of hippocampal replay in memory consolidation.