Articles in 2015

Research has revealed the molecular events that weaken connectivity in prefrontal cortical circuits during stress exposure. These events rapidly flip the brain from a reflective to reflexive state and may also contribute to degenerative changes in schizophrenia and Alzheimer's disease. This mechanistic understanding has translated to therapeutics for prefrontal disorders.

Environmental influences affect the brain and mental health and often are social or have social components, even the more complex societal or area-level exposures. This Review discusses the neural correlates of adverse and protective social influences and argues that innovative methods may provide ecologically more valid insights in social neuroscience.

In this review, Bale and Epperson discuss the importance of sex differences in stress found at all stages of life. As stress dysregulation is the most common feature across neuropsychiatric diseases, understanding sex differences in stress pathway development and maturation may predict disease risk and resilience factors across the lifespan.

Selective serotonin reuptake inhibitors (SSRIs) are widely used antidepressants, but the mechanisms by which they influence behavior are only partially resolved. Using a combination of different approaches, the authors demonstrate that serotonin 1A receptors expressed in mature dentate gyrus granule cells are critical mediators of the response to SSRIs.

The prevailing view for purinergic P2X receptor channels is that their ion conduction pores dilate upon prolonged activation. This study finds that the hallmark shift in equilibrium potential observed with prolonged channel activation does not result from pore dilation, but from time-dependent alterations in the concentration of intracellular ions.

New memory traces are believed to be reactivated and reorganized during sleep, mediated by the fine-tuned temporal interplay of neocortical slow oscillations, thalamo-cortical spindles and hippocampal ripples. The authors used intracranial recordings in humans to provide, for the first time, direct evidence for a systematic interaction of these oscillations in the human hippocampus.

ScaleS is a tissue clearing method for light and electron microscopy featuring stable tissue preservation for immunochemical and genetic labeling of tissue for 3D signal rendering. The technique enables quantitative and reproducible reconstructions of aged and diseased tissue in animal models and patients for high resolution optical pathology.

How does the brain stop a planned action that has suddenly become inappropriate? Here, Mayse et al. identify a novel subcortical mechanism of inhibitory control in the basal forebrain outside the canonical fronto-basal-ganglia circuit. Basal forebrain neuronal inhibition enables rapid behavioral stopping and also determines its speed.

Misfolded Aβ proteins can form proteopathic seeds that drive initiation, progression, and spreading of amyloidosis in the brain. Jucker and colleagues report that Aβ seeds can persist in mouse brain for months in the absence of host-derived Aβ and can then regain propagative and pathogenic activity in the presence of host Aβ.

The authors present a new observer model that combines efficient (en)coding and Bayesian decoding. The model makes the seemingly ‘anti-Bayesian’ prediction that perception can be biased away from an observer's prior expectations. Psychophysical data that previously were difficult to explain are well-matched by the model's prediction.

Based on the finding that the concentration of mRNA encoding olfactory chemoreceptors decreases after odorant stimulation, the authors developed a large-scale transcriptomic approach that allows the identification of ligand-chemoreceptor pairs in various species in vivo. This represents a critical step in our understanding of combinatorial coding of odors.

Dendrite arbor morphology is critical for neuron function. Yalgin and colleagues find that the activity of Centrosomin, used to build the mitotic spindle, is recycled after mitosis in dendrites. Centrosomin shapes the arbor by engaging microtubule nucleation at dendritic Golgi outposts to orient microtubule polarization in nascent branches.

Less is known about the role of amygdala circuits in anxiety than in acute fear responses. In this study, the authors demonstrate that aversive experience induces anxiety in mice by regulating the excitability of a defined subset of central amygdala neurons via extrasynaptic α₅ GABA_A receptors.

Using awake and freely behaving mice, this study employs a high-throughput in vivo RNA-seq approach to identify odorant receptor repertoires. The authors find sets of odorant receptors for two odorants encompassing 69 odorant receptor-odor pairs and develop models to predict receptor activation.

Dopamine loss in Parkinson's disease affects not only the basal ganglia, but also motor cortex, causing a surprising increase of spine turnover in the cortical dendritic tree and altering synaptic plasticity and memory retention.

Our internal states can color our memories just as powerfully as the external environment. A study finds that hippocampal GABA_A receptors and associated microRNAs are important for generating state-dependent contextual fear memories.

10 years ago, channelrhodopsin-2 was expressed in neurons and shown to control their activity. In this issue, we consider how the field has developed since these early optogenetic experiments.

How do individuals attribute dispositional properties, or traits, to others? A study suggests that associative learning processes underlie aspects of trait learning at both neural and behavioral levels.

Reflexes help us maintain a default posture and direction of locomotion. But what if we deliberately want to move differently? In Drosophila, the brain modifies a visually driven stabilization reflex to enable voluntary movements.