The morphological dietary preferences of an outbreaking population of corallivorous crown-of-thorns sea stars (Acanthaster sp.) in the Gulf of Thailand.

The current study investigated the morphological dietary preferences of an outbreaking population of corallivorous crown-of-thorn sea stars (Acanthaster sp.) in Koh Tao, situated in the Gulf of Thailand. The local effects of such populations deemed to be in outbreak are currently poorly understood.

Premature cognitive decline in a mouse model of tuberous sclerosis.

Little is known about the influence of (impaired) neurodevelopment on cognitive aging. We here used a mouse model for tuberous sclerosis (TS) carrying a heterozygous deletion of the Tsc2 gene. Loss of Tsc2 function leads to mTOR hyperactivity in mice and patients.

Representational maps in the brain: concepts, approaches, and applications.

Neural systems have evolved to process sensory stimuli in a way that allows for efficient and adaptive behavior in a complex environment. Recent technological advances enable us to investigate sensory processing in animal models by simultaneously recording the activity of large populations of neurons with single-cell resolution, yielding high-dimensional datasets. In this review, we discuss concepts and approaches for assessing the population-level representation of sensory stimuli in the form of a representational map.

An unbiased AAV-STARR-seq screen revealing the enhancer activity map of genomic regions in the mouse brain in vivo.

Enhancers are important cis-regulatory elements controlling cell-type specific expression patterns of genes. Furthermore, combinations of enhancers and minimal promoters are utilized to construct small, artificial promoters for gene delivery vectors. Large-scale functional screening methodology to construct genomic maps of enhancer activities has been successfully established in cultured cell lines, however, not yet applied to terminally differentiated cells and tissues in a living animal.

A stable sensory map emerges from a dynamic equilibrium of neurons with unstable tuning properties.

Recent long-term measurements of neuronal activity have revealed that, despite stability in large-scale topographic maps, the tuning properties of individual cortical neurons can undergo substantial reformatting over days. To shed light on this apparent contradiction, we captured the sound response dynamics of auditory cortical neurons using repeated 2-photon calcium imaging in awake mice. We measured sound-evoked responses to a set of pure tone and complex sound stimuli in more than 20,000 auditory cortex neurons over several days.

Learning-induced biases in the ongoing dynamics of sensory representations predict stimulus generalization.

Sensory stimuli have long been thought to be represented in the brain as activity patterns of specific neuronal assemblies. However, we still know relatively little about the long-term dynamics of sensory representations. Using chronic in vivo calcium imaging in the mouse auditory cortex, we find that sensory representations undergo continuous recombination, even under behaviorally stable conditions.

Rapid nucleus-scale reorganization of chromatin in neurons enables transcriptional adaptation for memory consolidation.

The interphase nucleus is functionally organized in active and repressed territories defining the transcriptional status of the cell. However, it remains poorly understood how the nuclear architecture of neurons adapts in response to behaviorally relevant stimuli that trigger fast alterations in gene expression patterns. Imaging of fluorescently tagged nucleosomes revealed that pharmacological manipulation of neuronal activity in vitro and auditory cued fear conditioning in vivo induce nucleus-scale restructuring of chromatin within minutes.

The Sensory Neocortex and Associative Memory.

Most behaviors in mammals are directly or indirectly guided by prior experience and therefore depend on the ability of our brains to form memories. The ability to form an association between an initially possibly neutral sensory stimulus and its behavioral relevance is essential for our ability to navigate in a changing environment. The formation of a memory is a complex process involving many areas of the brain.

Measuring the functional organization of the neocortex at large and small scales.

Sensory cortices are commonly structured topographically; however, the extent to which this organization principle is preserved at the microcircuit level is debated. In this issue of Neuron, Issa et al. (2014) revisit this question by combining calcium imaging in awake mice at large scales encompassing the whole auditory cortex and small scales providing single-cell resolution.

Analysis of transduction efficiency, tropism and axonal transport of AAV serotypes 1, 2, 5, 6, 8 and 9 in the mouse brain.

Recombinant Adeno-associated virus vectors (rAAV) are widely used for gene delivery and multiple naturally occurring serotypes have been harnessed to target cells in different tissues and organs including the brain. Here, we provide a detailed and quantitative analysis of the transduction profiles of rAAV vectors based on six of the most commonly used serotypes (AAV1, AAV2, AAV5, AAV6, AAV8, AAV9) that allows systematic comparison and selection of the optimal vector for a specific application. In our studies we observed marked differences among serotypes in the efficiency to transduce three different brain regions namely the striatum, hippocampus and neocortex of the mouse.