Barrels XXIII: Barrels by the shore

The 23rd annual Barrels meeting was held on the University of California, San Diego campus and highlighted the latest advances in the whisker-to-barrel pathway and beyond. The annual meeting brought together investigators from a dozen countries to present their data in posters and short talks. The meeting focused on several themes, first the barrel system was used as a model to study the consequences that result from alterations in the normal pattern(s) of development. A second session focused on what happens to whisker information once it leaves the layer IV barrel. A third session addressed issues of coding within the barrel system and a final session highlighted the latest advances in the engineering of transgenic mouse lines. The meeting highlighted the utility of the barrel system to study cortical circuitry in the normal and pathological state.     

Barrels XXX meeting report: Barrels in Baltimore

The Barrels meeting annually brings together researchers focused on the rodent whisker to cortical barrel system prior to the Society for Neuroscience meeting. The 2017 meeting focused on the classification of cortical interneurons, the role interneurons have in shaping brain dynamics, and finally on the circuitry underlying oral sensations. The meeting highlighted the latest advancements in this rapidly advancing field.     

Barrels by the sea: Barrels XX meeting report

The 20th annual Barrels meeting brought together researchers who utilize behavioral, physiological, anatomical, and molecular techniques to understand the structure and function of the barrel system. Barrels XX featured talks on the role inhibition has in shaping cortical responses within the barrel system, the molecular cues that influence the development of the whisker-to-barrel system, and the synaptic plasticity that can shape responses within the system. The meeting highlighted why the whisker-to-barrel system is an ideal model to investigate the development of cortical circuitry and how its functioning can influence behavioral responses.     

Barrels XXII meeting report: Barrels blow into the Windy City

The 22nd Annual Barrels Meeting blew into Evanston, near the Windy City, in November 2009 as the meeting was hosted on the Evanston, IL campus of Northwestern University. The longest running satellite meeting to the Society for Neuroscience Meeting annually brings together researchers from around the world focused on the development, function, behavior, and physiology of the rodent whisker-to-barrel system and other associated cortical and subcortical areas. The 2009 edition of the meeting was focused on three central themes: the molecular development and developmental plasticity in barrel cortex, optical analysis of barrel cortex function, and the coding of touch. The main symposia were complemented by short talks, data blitz sessions, and a poster session.     

Shrew communities in Eastern Transbaikalia

In the paper the author reports literature data and his own on the shrew fauna and communities of the steppe and forest zones of Eastern Transbaikalia.     

Barrels XXXI comes to the inland empire

The 31st annual Barrels meeting was held on the campus of the University of California, Riverside on the first two days of November, 2018. The meeting focuses on the whisker to cortical barrel pathway and the systems it impacts. This year’s meeting focussed on the neural mechanisms of motor control, the functions of higher order thalamic nuclei and adaptable perception and decision-making.     

Geographical distribution and habitat occurrence of the Water Shrew (Neomys fodiens) in the Weald of South-East England

A survey of 96 sites in a range of riparian habitats in the catchments of five rivers during June–August 1998 used the bait tube method to investigate the geographical distribution and habitat occurrence of Water Shrews (Neomys fodiens) in the Weald of South‐East England. Water Shrews were found at 42% of sites, and were widely distributed in all river catchments except the Mole. They occurred in many riparian habitats, including rivers, streams, canals and ditches, with a range of physical and biotic characteristics. There were no signs of habitat avoidance in response to human disturbance but Water Shrews were absent from the river catchment with lowest water quality. Logistic regression analysis was used to model the effect of habitat variables on the presence of Water Shrews, with current speed, water depth, bank incline and bank‐side vegetation identified as important variables. Fast‐flowing shallow waters had a significant positive effect on their presence, whereas scarce herbaceous vegetation and a bank of low incline had a significant negative effect. These habitat variables appear to be reliable indicators of the probability of finding Water Shrews at a particular site, and have implications for habitat management and conservation.     

Barrels XXXII meeting report: whiskers in the windy city

Abstract

The 32nd Annual Barrels meeting was hosted at the Northwestern University Feinberg School of Medicine in Chicago, Illinois on October 17th and 18th, 2019. The annual meeting brings together researchers who utilize the rodent whisker-to-barrel system as a means to understand cortical function and development. This year’s meeting focussed on social behaviours, development and cerebellar functions within the barrel system and beyond.     

Proceedings of the Barrels II Workshop: cortical circuits

The second session of the Barrels II Workshop focused on the function of cortical circuitry in the rodent vibrissa-to-barrel system. The session began with talks by Asaf Keller (University of Maryland), Christopher Moore (MIT), and David Pinto (Brown University). These presentations were followed by shorter talks by Mark Andermann (MIT), Alison Barth (Carnegie-Mellon University), Dirk Feldmeyer (Max Planck Institute), Cathy Garabedian (UCSF), Garrett Stanley (Harvard University), and Simona Temereanca (University of Pittsburgh). Presentations covered several central themes, including the functional organization of cortical circuitry, thalamocortical response transformations, temporal response properties, and the role of vibrissa resonance in high frequency representations. For simplicity, this review is organized by these central themes and does not follow the order of presentations at the meeting.     

Neonatal Androgen Affects Copulatory Behavior in the Female Musk Shrew

The role of neonatal testosterone in the development of copulatory behavior was examined in an insectivore, the musk shrew (Suncus murinus). Female musk shrews were treated with testosterone propionate (TP) for the first 5 days of life and then tested in adulthood for either female or male-like copulatory behavior. Early TP had a masculinizing effect; neonatally treated animals mounted a stimulus female more frequently, and with shorter latencies, in response to adult testosterone treatment than did control females. Neonatally androgenized females also showed deficits in female sexual behavior; few received ejaculations from stud males. This difference was likely caused by increased aggression exhibited by the neonatally TP-treated females toward males. In turn, female aggression decreased efficiency of male partners' intromission attempts. Early TP treatments also caused structural abnormalities in the ovaries, but did not effect their capacity to ovulate in response to either gonadotropin-releasing hormone or human chorionic gonadotropin injection. In sum, exposure to TP during development augmented display of male-like behavior in females and had subtle deleterious effects on expression of feminine behavior.     

Proceedings of the Barrels II Workshop: sensorimotor loops

Rodents use their whiskers to explore their environment and to make very fine discriminations in textures and sizes of objects. Exploratory "whisking" movements consist of large amplitude, rhythmic whisker protractions that occur at characteristic frequencies of 5-10 Hz. Rodents likely whisk to move their receptor surface over the object they are touching. A fundamental understanding of this important motor behavior and the sensorimotor loops that control it were the focus of the final session of the Barrels Workshop. This session began with talks from David Kleinfeld (University of California San Diego), Miguel Nicolelis (Duke University), and Jonathan Rubin (University of Pittsburgh). These talks were followed by short presentations from Steven Leiser (Drexel University), Marcin Szwed (Weitzman Institute), Ford Ebner (Vanderbilt University), Charles Pluto (Medical College of Ohio), and Elisabeth Foeller (Washington University).     

Exfoliated MoS2 in Water without Additives

Many solution processing methods of exfoliation of layered materials have been studied during the last few years; most of them are based on organic solvents or rely on surfactants and other funtionalization agents. Pure water should be an ideal solvent, however, it is generally believed, based on solubility theories that stable dispersions of water could not be achieved and systematic studies are lacking. Here we describe the use of water as a solvent and the stabilization process involved therein. We introduce an exfoliation method of molybdenum disulfide (MoS₂) in pure water at high concentration (i.e., 0.14 ± 0.01 g L⁻¹). This was achieved by thinning the bulk MoS₂ by mechanical exfoliation between sand papers and dispersing it by liquid exfoliation through probe sonication in water. We observed thin MoS₂ nanosheets in water characterized by TEM, AFM and SEM images. The dimensions of the nanosheets were around 200 nm, the same range obtained in organic solvents. Electrophoretic mobility measurements indicated that electrical charges may be responsible for the stabilization of the dispersions. A probability decay equation was proposed to compare the stability of these dispersions with the ones reported in the literature. Water can be used as a solvent to disperse nanosheets and although the stability of the dispersions may not be as high as in organic solvents, the present method could be employed for a number of applications where the dispersions can be produced on site and organic solvents are not desirable.     

实验室繁育树鼩生理指标的检测分析

对实验室繁育的22只成年树鼩进行生理指标的检测,并与正常人参考值进行对比分析。结果显示,树鼩红细胞数8.19×1012/L,高于人参考值上限;白细胞数2.21×109/L,低于人参考值下限;肌酐16.63μmol/L,低于人参考值下限;丙氨酸氨基转移酶77.92U/L和天门冬氨酸氨基转移酶179.9U/L,都高于人参考值上限;HBsAg均为阴性0.022ng/ml±0.005。表明树鼩作为更接近人类的低等灵长类动物,适合应用于研究人类疾病的动物模型。     

树鼩在医学实验研究中的新进展

树鼩的许多生物学特性近似于人类,人们利用树鼩成功建立了多种人类病毒感染的动物模型,并在肿瘤、内分泌、神经、视觉等方面有相当广泛和深入的应用和研究。本文概述了树鼩在医学实验研究中的新进展。     

Subbarrel Patterns in Somatosensory Cortical Barrels Can Emerge from Local Dynamic Instabilities

Complex spatial patterning, common in the brain as well as in other biological systems, can emerge as a result of dynamic interactions that occur locally within developing structures. In the rodent somatosensory cortex, groups of neurons called “barrels” correspond to individual whiskers on the contralateral face. Barrels themselves often contain subbarrels organized into one of a few characteristic patterns. Here we demonstrate that similar patterns can be simulated by means of local growth-promoting and growth-retarding interactions within the circular domains of single barrels. The model correctly predicts that larger barrels contain more spatially complex subbarrel patterns, suggesting that the development of barrels and of the patterns within them may be understood in terms of some relatively simple dynamic processes. We also simulate the full nonlinear equations to demonstrate the predictive value of our linear analysis. Finally, we show that the pattern formation is robust with respect to the geometry of the barrel by simulating patterns on a realistically shaped barrel domain. This work shows how simple pattern forming mechanisms can explain neural wiring both qualitatively and quantitatively even in complex and irregular domains.     

树鼩在医学生物学中的应用

目的树鼩是一种新型实验动物,由于它的许多分子与细胞结构近似于人类,已成功建立了多种人类病毒感染的动物模型,并在神经生物学、生殖生物学、免疫学和社会心理学等方面有相当广泛和深入的应用和研究。     

Water Developments and Canids in Two North American Deserts: A Test of the Indirect Effect of Water Hypothesis

Anthropogenic modifications to landscapes intended to benefit wildlife may negatively influence wildlife communities. Anthropogenic provisioning of free water (water developments) to enhance abundance and distribution of wildlife is a common management practice in arid regions where water is limiting. Despite the long-term and widespread use of water developments, little is known about how they influence native species. Water developments may negatively influence arid-adapted species (e.g., kit fox, Vulpes macrotis) by enabling water-dependent competitors (e.g., coyote, Canis latrans) to expand distribution in arid landscapes (i.e., indirect effect of water hypothesis). We tested the two predictions of the indirect effect of water hypothesis (i.e., coyotes will visit areas with free water more frequently and kit foxes will spatially and temporally avoid coyotes) and evaluated relative use of free water by canids in the Great Basin and Mojave Deserts from 2010 to 2012. We established scent stations in areas with (wet) and without (dry) free water and monitored visitation by canids to these sites and visitation to water sources using infrared-triggered cameras. There was no difference in the proportions of visits to scent stations in wet or dry areas by coyotes or kit foxes at either study area. We did not detect spatial (no negative correlation between visits to scent stations) or temporal (no difference between times when stations were visited) segregation between coyotes and kit foxes. Visitation to water sources was not different for coyotes between study areas, but kit foxes visited water sources more in Mojave than Great Basin. Our results did not support the indirect effect of water hypothesis in the Great Basin or Mojave Deserts for these two canids.