Hypothalamic melanin-concentrating hormone (MCH) neurons are important regulators of multiple physiological processes, such as sleep, feeding, and memory. Despite the increasing interest in their neuronal functions, the molecular mechanism underlying MCH neuron development remains poorly understood. We report that a three-dimensional culture of mouse embryonic stem cells (mESCs) can generate hypothalamic-like tissues containing MCH-positive neurons, which reproduce morphologic maturation, neuronal connectivity, and neuropeptide/neurotransmitter phenotype of native MCH neurons. Using this in vitro system, we demonstrate that Hedgehog (Hh) signaling serves to produce major neurochemical subtypes of MCH neurons characterized by the presence or absence of cocaine- and amphetamine-regulated transcript (CART). Without exogenous Hh signals, mESCs initially differentiated into dorsal hypothalamic/prethalamic progenitors and finally into MCH+CART+ neurons through a specific intermediate progenitor state. Conversely...

Cortical GABAergic interneurons have been shown to fulfil important roles by inhibiting excitatory principal neurons. Recent transcriptomic studies have confirmed seminal discoveries that used anatomic and electrophysiological methods highlighting the existence of multiple different classes of GABAergic interneurons. Although some of these studies have emphasized that inter-regional differences may exist for a given class, the extent of such differences remains unknown. To address this problem, we used single-cell Patch-RNAseq to characterize neuropeptide Y (NPY)-positive GABAergic interneurons in superficial layers of the primary auditory cortex (AC) and in distal layers of area CA3 in mice. We found that more than 300 genes are differentially expressed in NPY-positive neurons between these two brain regions. For example, the AMPA receptor (AMPAR) auxiliary subunit Shisa9/CKAMP44 and the 5HT2a receptor (5HT2aR) are significantly higher expressed in auditory NPY-positive neurons. These findings guided us t...

In the article, “Automated Detection and Localization of Synaptic Vesicles in Electron Microscopy Images,” by Barbara Imbrosci, Dietmar …

We assessed similarities and differences in the electrographic signatures of local field potentials evoked by different pharmacological agents in zebrafish larvae. We then compared and contrasted these characteristics with what is known from electrophysiological studies of seizures and epilepsy in mammals, including humans. Ultimately, our aim was to phenotype neurophysiological features of drug-induced seizures in larval zebrafish for expanding knowledge on the translational potential of this valuable alternative to mammalian models. Local field potentials were recorded from the midbrain of 4-day old zebrafish larvae exposed to a pharmacologically diverse panel of seizurogenic compounds, and the outputs of these recordings were assessed using frequency domain analysis. This included analysis of changes occurring within various spectral frequency bands of relevance to mammalian CNS circuit pathophysiology. From these analyses, there were clear differences in the frequency spectra of drug-exposed local fiel...

The neural basis of attention is thought to involve the allocation of limited neural resources. However, the quantitative validation of this hypothesis remains challenging. Here, we provide quantitative evidence that the nonuniform allocation of neural resources across the whole cerebral gray matter reflects the broad-task process of sustained attention. We propose a neural measure for the nonuniformity of whole-cerebral allocation using functional magnetic resonance imaging. We found that this measure was significantly correlated with conventional indicators of attention level, such as task difficulty and pupil dilation. We further found that the broad-task neural correlates of the measure belong to fronto-parietal and dorsal attention networks. Finally, we found that patients with attention-deficit/hyperactivity disorder showed abnormal decreases in the level of the proposed measure reflecting the executive dysfunction. This study proposes a neuromarker suggesting that the nonuniform allocation of neural...

To better understand complex systems, such as the brain, studying the interactions between multiple brain regions is imperative. Such experiments often require delineation of multiple brain regions on microscopic images based on pre-existing brain atlases. Experiments examining the relationships of multiple regions across the brain have traditionally relied on manual plotting of regions. This process is very intensive and becomes untenable with a large number of regions of interest. To reduce the amount of time required to process multi-region datasets, several tools for atlas registration have been developed; however, these tools are often inflexible to tissue type, only supportive of a limited number of atlases and orientation, require considerable computational expertise, or are only compatible with certain types of microscopy. To address the need for a simple yet extensible atlas registration tool we have developed FASTMAP, a flexible atlas segmentation tool for multi-area processing. We demonstrate it...

Here we investigate stimulus generalization in a cerebellar learning paradigm, called eyeblink conditioning. Mice were conditioned to close their eyes in response to a 10 kHz tone by repeatedly pairing this tone with an air puff to the eye 250 ms after tone onset. After ten consecutive days of training, when mice showed reliable conditioned eyelid responses to the 10 kHz tone, we started to expose them to tones with other frequencies, ranging from 2 to 20 kHz. We found that mice had a strong generalization gradient, whereby the probability and amplitude of conditioned eyelid responses gradually decreases depending on the dissimilarity with the 10 kHz tone. Tones with frequencies closest to 10kHz evoked the most and largest conditioned eyelid responses and each step away from the 10 kHz tone resulted in fewer and smaller conditioned responses. In addition, we found that tones with lower frequencies resulted in conditioned responses that peaked earlier after tone onset compared to those to tones with higher ...

Modern molecular and biochemical neuroscience studies require analysis of specific cellular populations derived from brain tissue samples to disambiguate cell type-specific events. This is particularly true in the analysis of minority glial populations in the brain, such as microglia, which may be obscured in whole tissue analyses. Microglia have central functions in development, aging, and neurodegeneration and are a current focus of neuroscience research. A long-standing concern for glial biologists using in vivo models is whether cell isolation from CNS tissue could introduce ex vivo artifacts in microglia, which respond quickly to changes in the environment. Mouse microglia were purified by magnetic-activated cell sorting (MACS), as well as cytometer- and cartridge-based fluorescence-activated cell sorting (FACS) approaches to compare and contrast performance. The Cx3cr1-NuTRAP mouse model was used to provide an endogenous fluorescent microglial marker and a microglial-specific translatome profile as a...

Understanding the human brain is a ‘Grand Challenge’ for 21st century research. Computational approaches enable large and complex datasets to be addressed efficiently, supported by artificial neural networks, modeling and simulation. Dynamic generative multiscale models, which enable causation across scales and are guided by principles and theories of brain function, are instrumental to link brain structure and function. This integrated approach to neuroscientific discovery is framed within the BigBrain, which spatially anchors tissue models and data across different spatial scales and assures that multiscale models are supported by the data, making the bridge to both basic neuroscience and medicine. Research at the cross-over of neuroscience, computing and robotics has the potential to push neuro-inspired technologies, taking advantage of a growing body of insights into perception, plasticity and learning. To render data, tools and methods, theories, basic principles and concepts interoperable, the Human ...

Studying the temporal dynamics of perceptual decisions offers key insights into the cognitive processes contributing to it. Conducting such investigation in a genetically tractable animal model can facilitate the subsequent unpacking of the mechanistic basis of different stages in perceptual dynamics. Here, we investigated the time course as well as fundamental psychophysical constants governing visual perceptual decision-making in freely behaving mice. We did so by analyzing response accuracy against reaction time (i.e., conditional accuracy), in a series of 2-AFC orientation discrimination tasks in which we varied target size, luminance, duration, and presence of a foil. Our results quantified two distinct stages in the time course of mouse visual decision-making - a ‘sensory encoding’ stage, in which conditional accuracy exhibits a classic tradeoff with response speed, and a subsequent ‘short term memory (STM)-dependent’ stage in which conditional accuracy exhibits a classic asymptotic decay following s...