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neuronal circuits

Skyler L Jackman, Christopher H Chen, Selmaan N Chettih, Shay Q Neufeld, Iain R Drew, Chimuanya K Agba, Isabella Flaquer, Alexis N Stefano, Thomas J Kennedy, Justine E Belinsky, Keiramarie Roberston, Celia C Beron, Bernardo L Sabatini, Christopher D Harvey, Wade G Regehr
Optical methods of interrogating neural circuits have emerged as powerful tools for understanding how the brain drives behaviors. Optogenetic proteins are widely used to control neuronal activity, while genetically encoded fluorescent reporters are used to monitor activity. These proteins are often expressed by injecting viruses, which frequently leads to inconsistent experiments due to misalignment of expression and optical components. Here, we describe how silk fibroin films simplify optogenetic experiments by providing targeted delivery of viruses...
March 20, 2018: Cell Reports
Manami Yamashita, Shin-Ya Kawaguchi, Tetsuya Hori, Tomoyuki Takahashi
Synaptic efficacy plays crucial roles in neuronal circuit operation and synaptic plasticity. Presynaptic determinants of synaptic efficacy are neurotransmitter content in synaptic vesicles and the number of vesicles undergoing exocytosis at a time. Bursts of presynaptic firings depress synaptic efficacy, mainly due to depletion of releasable vesicles, whereas recovery from strong depression is initiated by endocytic vesicle retrieval followed by refilling of vesicles with neurotransmitter. We washed out presynaptic cytosolic GABA to induce a rundown of IPSCs at cerebellar inhibitory cell pairs in slices from rats and then allowed fast recovery by elevating GABA concentration using photo-uncaging...
March 20, 2018: Cell Reports
Andres Canales, Seongjun Park, Antje Kilias, Polina Anikeeva
Multifunctional devices for modulation and probing of neuronal activity during free behavior facilitate studies of functions and pathologies of the nervous system. Probes composed of stiff materials, such as metals and semiconductors, exhibit elastic and chemical mismatch with the neural tissue, which is hypothesized to contribute to sustained tissue damage and gliosis. Dense glial scars have been found to encapsulate implanted devices, corrode their surfaces, and often yield poor recording quality in long-term experiments...
March 21, 2018: Accounts of Chemical Research
Xiaoxiao Lin, Christy A Itoga, Sharif Taha, Ming H Li, Ryan Chen, Kirolos Sami, Fulvia Berton, Walter Francesconi, Xiangmin Xu
Real-world stressors are complex and multimodal, involving physical, psychological, and social dimensions. However, the brain networks that mediate stress responses to these stimuli need to be further studied. We used c-Fos mapping in mice to characterize brain circuits activated by exposure to a single episode of multimodal stress (MMS), and compared these to circuits activated by electric foot shocks (EFS). We focused on characterizing c-Fos activity in stress-relevant brain regions including the paraventricular nucleus (PVN) of the hypothalamus and the bed nucleus of the stria terminalis (BNST)...
February 2018: Neurobiology of Stress
Dhrubajyoti Chowdhury, Johannes W Hell
The ability of neurons and circuits to maintain their excitability and activity levels within the appropriate dynamic range by homeostatic mechanisms is fundamental for brain function. Neuronal hyperactivity, for instance, could cause seizures.  One such homeostatic process is synaptic scaling, also known as synaptic homeostasis. It involves a negative feedback process by which neurons adjust (scale) their postsynaptic strength over their whole synapse population to compensate for increased or decreased overall input thereby preventing neuronal hyper- or hypoactivity that could otherwise result in neuronal network dysfunction...
2018: F1000Research
Hector Zurita, Paul L C Feyen, Alfonso Junior Apicella
Previous studies have shown that parvalbumin-expressing neurons (CC-Parv neurons) connect the two hemispheres of motor and sensory areas via the corpus callosum, and are a functional part of the cortical circuit. Here we test the hypothesis that layer 5 CC-Parv neurons possess anatomical and molecular mechanisms which dampen excitability and modulate the gating of interhemispheric inhibition. In order to investigate this hypothesis we use viral tracing to determine the anatomical and electrophysiological properties of layer 5 CC-Parv and parvalbumin-expressing (Parv) neurons of the mouse auditory cortex (AC)...
2018: Frontiers in Cellular Neuroscience
Jörg Encke, Werner Hemmert
The mammalian auditory system is able to extract temporal and spectral features from sound signals at the two ears. One important cue for localization of low-frequency sound sources in the horizontal plane are inter-aural time differences (ITDs) which are first analyzed in the medial superior olive (MSO) in the brainstem. Neural recordings of ITD tuning curves at various stages along the auditory pathway suggest that ITDs in the mammalian brainstem are not represented in form of a Jeffress-type place code. An alternative is the hemispheric opponent-channel code, according to which ITDs are encoded as the difference in the responses of the MSO nuclei in the two hemispheres...
2018: Frontiers in Neuroscience
Xin Liu, Yichen Lu, Ege Iseri, Yuhan Shi, Duygu Kuzum
Electrophysiology is a decades-old technique widely used for monitoring activity of individual neurons and local field potentials. Optogenetics has revolutionized neuroscience studies by offering selective and fast control of targeted neurons and neuron populations. The combination of these two techniques is crucial for causal investigation of neural circuits and understanding their functional connectivity. However, electrical artifacts generated by light stimulation interfere with neural recordings and hinder the development of compact closed-loop systems for precise control of neural activity...
2018: Frontiers in Neuroscience
María Lázaro-Peña, Carlos Díaz-Balzac, Hannes Bülow, Scott Emmons
The nervous system regulates complex behaviors through a network of neurons interconnected by synapses. How specific synaptic connections are genetically determined is still unclear. Male mating is the most complex behavior in C. elegans It is composed of sequential steps that are governed by more than 3,000 chemical connections. Here we show that heparan sulfates (HS) play a role in the formation and function of the male neural network. HS, sulfated in position 3 by the HS modification enzyme HST-3.1 / HS 3- O -sulfotransferase and attached to the HSPG glypicans LON-2/glypican and GPN-1/glypican, functions cell-autonomously and non-autonomously for response to hermaphrodite contact during mating...
March 20, 2018: Genetics
Graziana Gatto, Martyn Goulding
Three new and closely complementary studies have defined the architecture of the circuits underlying the descending control of locomotion, identifying neurons that drive fast motor responses and those that seem to be specialised for exploratory behaviors.
March 19, 2018: Current Biology: CB
Sabato Santaniello, John T Gale, Sridevi V Sarma
Over the last 30 years, deep brain stimulation (DBS) has been used to treat chronic neurological diseases like dystonia, obsessive-compulsive disorders, essential tremor, Parkinson's disease, and more recently, dementias, depression, cognitive disorders, and epilepsy. Despite its wide use, DBS presents numerous challenges for both clinicians and engineers. One challenge is the design of novel, more efficient DBS therapies, which are hampered by the lack of complete understanding about the cellular mechanisms of therapeutic DBS...
March 20, 2018: Wiley Interdisciplinary Reviews. Systems Biology and Medicine
Yun-Ting Su, Meng-Yang Gu, Xi Chu, Xiang Feng, Yan-Qin Yu
The GABAergic neurons in the parafacial zone (PZ) play an important role in sleep-wake regulation and have been identified as part of a sleep-promoting center in the brainstem, but the long-range connections mediating this function remain poorly characterized. Here, we performed whole-brain mapping of both the inputs and outputs of the GABAergic neurons in the PZ of the mouse brain. We used the modified rabies virus EnvA-ΔG-DsRed combined with a Cre/loxP gene-expression strategy to map the direct monosynaptic inputs to the GABAergic neurons in the PZ, and found that they receive inputs mainly from the hypothalamic area, zona incerta, and parasubthalamic nucleus in the hypothalamus; the substantia nigra, pars reticulata and deep mesencephalic nucleus in the midbrain; and the intermediate reticular nucleus and medial vestibular nucleus (parvocellular part) in the pons and medulla...
March 20, 2018: Neuroscience Bulletin
Xing Chen, Wang Kang, Daoqian Zhu, Xichao Zhang, Na Lei, Youguang Zhang, Yan Zhou, Weisheng Zhao
Neuromorphic computing, which relies on a combination of a large number of neurons massively interconnected by an even larger number of synapses, has been actively studied for its characteristics such as energy efficiency, intelligence, and adaptability. To date, while the development of artificial synapses has shown great progress with the introduction of emerging nanoelectronic devices, e.g., memristive devices, the implementation of artificial neurons, however, depends mostly on semiconductor-based circuits via integrating many transistors, sacrificing energy efficiency and integration density...
March 20, 2018: Nanoscale
Jing Huang, Erika Polgár, Hans Jürgen Solinski, Santosh K Mishra, Pang-Yen Tseng, Noboru Iwagaki, Kieran A Boyle, Allen C Dickie, Mette C Kriegbaum, Hendrik Wildner, Hanns Ulrich Zeilhofer, Masahiko Watanabe, John S Riddell, Andrew J Todd, Mark A Hoon
Stimuli that elicit itch are detected by sensory neurons that innervate the skin. This information is processed by the spinal cord; however, the way in which this occurs is still poorly understood. Here we investigated the neuronal pathways for itch neurotransmission, particularly the contribution of the neuropeptide somatostatin. We find that in the periphery, somatostatin is exclusively expressed in Nppb+ neurons, and we demonstrate that Nppb+ somatostatin+ cells function as pruriceptors. Employing chemogenetics, pharmacology and cell-specific ablation methods, we demonstrate that somatostatin potentiates itch by inhibiting inhibitory dynorphin neurons, which results in disinhibition of GRPR+ neurons...
March 19, 2018: Nature Neuroscience
Leonie Asboth, Lucia Friedli, Janine Beauparlant, Cristina Martinez-Gonzalez, Selin Anil, Elodie Rey, Laetitia Baud, Galyna Pidpruzhnykova, Mark A Anderson, Polina Shkorbatova, Laura Batti, Stephane Pagès, Julie Kreider, Bernard L Schneider, Quentin Barraud, Gregoire Courtine
Severe spinal cord contusions interrupt nearly all brain projections to lumbar circuits producing leg movement. Failure of these projections to reorganize leads to permanent paralysis. Here we modeled these injuries in rodents. A severe contusion abolished all motor cortex projections below injury. However, the motor cortex immediately regained adaptive control over the paralyzed legs during electrochemical neuromodulation of lumbar circuits. Glutamatergic reticulospinal neurons with residual projections below the injury relayed the cortical command downstream...
March 19, 2018: Nature Neuroscience
Jun-Bin Yin, Ya-Cheng Lu, Ban Feng, Zhen-Yu Wu, Ying-Biao Chen, Ting Zhang, Zhen-Zhen Kou, Ming-Ming Zhang, Han Zhang, Jin-Lian Li, Hui Li, Tao Chen, Yu-Lin Dong, Yun-Qing Li
BACKGROUND/AIMS: Spinal dorsal horn (SDH) is one of the most important regions for analgesia produced by endomorphin-2 (EM2), which has a higher affinity and specificity for the µ-opioid receptor (MOR) than morphine. Many studies have focused on substantia gelatinosa (SG, lamina II) neurons to elucidate the cellular basis for its antinociceptive effects. However, the complicated types and local circuits of interneurons in the SG make it difficult to understand the real effects of EM2...
March 15, 2018: Neuro-Signals
Daniel Pensold, Geraldine Zimmer
The correct establishment of inhibitory circuits is crucial for cortical functionality and defects during the development of γ-aminobutyric acid-expressing cortical interneurons contribute to the pathophysiology of psychiatric disorders. A critical developmental step is the migration of cortical interneurons from their site of origin within the subpallium to the cerebral cortex, orchestrated by intrinsic and extrinsic signals. In addition to genetic networks, epigenetic mechanisms such as DNA methylation by DNA methyltransferases (DNMTs) are suggested to drive stage-specific gene expression underlying developmental processes...
2018: Journal of Experimental Neuroscience
Mateo Vélez-Fort, Edward F Bracey, Sepiedeh Keshavarzi, Charly V Rousseau, Lee Cossell, Stephen C Lenzi, Molly Strom, Troy W Margrie
To interpret visual-motion events, the underlying computation must involve internal reference to the motion status of the observer's head. We show here that layer 6 (L6) principal neurons in mouse primary visual cortex (V1) receive a diffuse, vestibular-mediated synaptic input that signals the angular velocity of horizontal rotation. Behavioral and theoretical experiments indicate that these inputs, distributed over a network of 100 L6 neurons, provide both a reliable estimate and, therefore, physiological separation of head-velocity signals...
March 8, 2018: Neuron
Larisa V Lysenko, Jeesun Kim, Francisco Madamba, Anna A Tyrtyshnaia, Aarti Ruparelia, Alexander M Kleschevnikov
Down syndrome (DS) is the most frequent genetic cause of developmental abnormalities leading to intellectual disability. One notable phenomenon affecting the formation of nascent neural circuits during late developmental periods is developmental switch of GABA action from depolarizing to hyperpolarizing mode. We examined properties of this switch in DS using primary cultures and acute hippocampal slices from Ts65Dn mice, a genetic model of DS. Cultures of DIV3-DIV13 Ts65Dn and control normosomic (2 N) neurons were loaded with FURA-2 AM, and GABA action was assessed using local applications...
March 14, 2018: Neurobiology of Disease
Dong-Oh Seo, Laura E Motard, Michael R Bruchas
Great efforts in clinical and basic research have shown progress in understanding the neurobiological mechanisms of neurodevelopmental disorders, such as autism, schizophrenia, and attention-deficit hyperactive disorders. Literature on this field have suggested that these disorders are affected by the complex interaction of genetic, biological, psychosocial and environmental risk factors. However, this complexity of interplaying risk factors during neurodevelopment has prevented a complete understanding of the causes of those neuropsychiatric symptoms...
March 14, 2018: Neurobiology of Learning and Memory
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