Articles in 2014

A study now suggests that tau-induced reactive oxygen species relax chromatin, which leads to expression of PIWIL1, cell cycle reentry and neurodegeneration.

A study finds that, during movement preparation, when motor cortex is active, but elicits no muscle output, firing of individual neurons in dorsal premotor and primary motor cortex cancels out at the level of population activity.

In this Perspective, the authors review the literature and suggest that the cognitive pathology that often accompanies preterm birth and/or very low birth weight may be a direct result of perinatal hypoxia that, in turn, leads to perturbations in the maturation and development of interneurons, oligodendrocytes and astrocytes.

Working memory is thought to be limited in capacity, holding a fixed, small number of items, but it has recently been proposed that working memory might be conceptualized as a limited resource that is distributed flexibly between all items to be maintained in memory. In this review, the authors consider emerging evidence for this proposal.

This study shows that activity-dependent palmitoylation of δ-catenin stabilizes the cell adhesion molecule N-cadherin at the excitatory synapse and that this post-translational modification is important for GluA1- and GluA2-mediated synaptic and structural plasticity.

In this study, the authors show that there are multiple forms of opioid-induced long-term depression (OP-LTD) in the dorsal striatum, each mediated by the mu, delta or kappa opioid receptor. The mu and delta OP-LTD are presynaptic and can summate, but only mu OP-LTD occludes endocannabinoid-induced LTD. Furthermore, mu OP-LTP, but not kappa or delta OP-LTP, is blocked by the analgesic oxycodone.

In this Technical Report, the authors describe a new technique for the unambiguous lineage tracing of specific Drosophila neuroblasts. This methodology involves the use of lineage-restricted drivers and a modification to GAL4 expression such that it is now permanent and heritable to all descendant cells, directing reporter expression based on neuroblast identity rather than terminal neuronal characteristics.

The authors examine magnetoencephalographic recordings during relevant- and irrelevant-feature processing in a visual attention task. As participants attend to stimulus color or motion, a temporal sequence of relevant followed by irrelevant feature activations may bind an attended object's features into a unitary percept.

Sparse coding is thought to facilitate pattern separation for associative memory, but behavioral evidence is scant. The authors show that in Drosophila, feedback inhibition enforces sparse odor coding in Kenyon cells, the neurons that store olfactory associations. Disrupting this sparsening mechanism impairs learned discrimination of similar, but not dissimilar, odors.

Here the author shows that an unstructured, sparsely connected network of model spiking neurons can display two different types of asynchronous activity: one in which an external input leads to a highly redundant response of different neurons that favors information transmission and another in which the firing rates of individual neurons fluctuate strongly in time and across neurons to provide a substrate for complex information processing.

In this study, the authors show that altering the photoperiod of mice results in reversible transcriptional and DNA methylation changes in the suprachiasmatic nucleus. Application of a methyltransferase inhibitor blocks the light-entrained changes in the circadian period, suggesting that these methylation changes directly mediate circadian plasticity.

To adaptively navigate their environments organisms need to predict and cancel out the sensory consequences of their actions. Here the authors show that granule cells within the cerebellum-like structure of weakly electric fish have delayed responses that closely match the timing of self-generated sensory inputs. This enables corollary discharges to be transformed into negative images that are well-tuned to the animal's own behavior.

This study shows that activation of cannabinoid type-1 (CB1) receptors in the olfactory bulb increases odor detection and food intake in hungry mice. The authors show that this function is mediated by CB1-dependent attenuation of excitatory corticofugal synaptic transmission onto inhibitory granule cells and disinhibition of mitral cells in the main olfactory bulb.

Decision-making research has often focused on decisions between two options. The authors adapted a decision-making model to account for a third, unavailable option, and they found that decision-making was more difficult with a poorer, and not better, third alternative. Ventromedial prefrontal cortex activity predicted individual variation in decision-making with multiple options.

Microglia are involved in synaptic pruning during development. Here the authors show that mice deficient in the fractalkine receptor Cx3cr1, which show a transient reduction in microglia, have reduced synaptic multiplicity in the hippocampus, decreased functional connectivity between the prefrontal cortex and hippocampus and altered social and repetitive behaviors.

Brain areas directly involved in driving movement are active well before movement begins. Muscle activity is some readout of this neural activity, yet remains largely unchanged during preparation. Here the authors find that during movement preparation, changes in motor cortical activity cancel out at the level of population activity within dorsal premotor and primary motor cortex.

The authors use monkey electrophysiology data to test a “bump attractor” computational model. Their findings reinforce persistent activity as a basis for spatial working memory, provide evidence for a continuous prefrontal representation of memorized space, and offer experimental support for bump attractor dynamics mediating cognitive tasks in the cortex.

The pedunculopontine nucleus (PPN) is a target for deep brain stimulation for the control of gait and postural disability, but its role in gait control is not understood. Here, using extracellular single-unit recordings in awake patients, the authors show that neurons in the PPN respond to limb movement and imagined gait by dynamically changing network activity and decreasing alpha phase locking.

In vitro evidence suggests that the tuft dendrites of pyramidal neurons can evoke local NMDA spikes. The authors find that these local NMDA spikes occur spontaneously and following sensory input, and influence the number of output action potentials.