Temporal Map Formation in the Barn Owl’s Brain

Barn owls provide an experimentally well-specified example of a temporal map, a neuronal representation of the outside world in the brain by means of time. Their laminar nucleus exhibits a place code of interaural time differences, a cue which is used to determine the azimuthal location of a sound stimulus, e.g., prey. We analyze a model of synaptic plasticity that explains the formation of such a representation in the young bird and show how in a large parameter regime a combination of local and nonlocal synaptic plasticity yields the temporal map as found experimentally. Our analysis includes the effect of nonlinearities as well as the influence of neuronal noise

Population Differentiation In Daphnia Alters Community Assembly In Experimental Ponds

Most studies of community assembly ignore how genetic differentiation within species affects their colonization and extinction. However, genetic differentiation in ecologically relevant traits may be substantial enough to alter the colonization and extinction processes that drive community assembly. We measured significant molecular genetic and quantitative trait differentiation among three Daphnia pulex X pulicaria populations in southwestern Michigan ponds and investigated whether this differentiation could alter the assembly of pond zooplankton communities in experimental mesocosms. In this study, we monitored the invasion success of different D. pulex x pulicaria populations after their introduction into an established zooplankton community. We also monitored the invasion success of a diverse array of zooplankton species into different D. pulex x pulicaria populations. Zooplankton community composition depended on the D. pulex X pulicaria source population. Daphnia pulex X pulicaria from one population failed to invade zooplankton communities, while those from other populations successfully invaded similar communities. If population differentiation in other species plays a role in community assembly similar to that demonstrated in our study, assembly may be more sensitive to evolutionary processes than has been previously generally considered.Integrative Biolog

The role of the immune system in brain metastasis

Metastatic brain tumors are the most common brain tumors in adults. With numerous successful advancements in systemic treatment of most common cancer types, brain metastasis is becoming increasingly important in the overall prognosis of cancer patients. Brain metastasis of peripheral tumor is the result of complex interplay of primary tumor, immune system and central nervous system microenvironment. Once formed, brain metastases hide behind the blood brain barrier and become inaccessible to chemotherapies that are otherwise successful in targeting systemic cancer. The approval of immune checkpoint inhibitors for several common cancers such as advanced melanoma and lung cancers brings with it the opportunity and obligation to further understand the mechanisms of immunosuppression by tumors that spread to the brain as well as the interaction between the brain environment and tumor microenvironment. In this review paper we define the central role of the immune system in the development of brain metastases. We performed a comprehensive review of the literature to outline the molecular mechanisms of immunosuppression used by tumors and how the immune system interacts with the central nervous system to facilitate brain metastasis. In particular we discuss the tumor-type-specific mechanisms of metastasis of cancers that preferentially metastasize to the brain as well as the therapies that effectively modulate the immune response, such as immune checkpoint inhibitors and vaccines

Renewal theory of coupled neuronal pools

A theory is provided to analyze the dynamics of delay-coupled pools of spiking neurons based on stability analysis of stationary firing. Transitions between stable and unstable regimes can be predicted by bifurcation analysis of the underlying integral dynamics. Close to the bifurcation point the network exhibits slowly changingactivities and allows for slow collective phenomena like continuous attractors

Single-Trial Phase Precession in the Hippocampus

During the crossing of the place field of a pyramidal cell in the rat hippocampus, the firing phase of the cell decreases with respect to the local theta rhythm. This phase precession is usually studied on the basis of data in which many place field traversals are pooled together. Here we study properties of phase precession in single trials. We found that single-trial and pooled-trial phase precession were different with respect to phase-position correlation, phase-time correlation, and phase range. Whereas pooled-trial phase precession may span 360°, the most frequent single-trial phase range was only ∼180°. In pooled trials, the correlation between phase and position (r = −0.58) was stronger than the correlation between phase and time (r = −0.27), whereas in single trials these correlations (r = −0.61 for both) were not significantly different. Next, we demonstrated that phase precession exhibited a large trial-to-trial variability. Overall, only a small fraction of the trial-to-trial variability in measures of phase precession (e.g., slope or offset) could be explained by other single-trial properties (such as running speed or firing rate), whereas the larger part of the variability remains to be explained. Finally, we found that surrogate single trials, created by randomly drawing spikes from the pooled data, are not equivalent to experimental single trials: pooling over trials therefore changes basic measures of phase precession. These findings indicate that single trials may be better suited for encoding temporally structured events than is suggested by the pooled data

The Wheel of Business Model Reinvention: How to Reshape Your Business Model and Organizational Fitness to Leapfrog Competitors

In today's rapidly changing business landscapes, new sources of sustainable competitive advantage can often only be attained from business model reinvention, based on disruptive innovation and not incremental change or continuous improvement. Extant literature indicates that business models and their reinvention have recently been the focus of scholarly investigations in the field of strategic management, especially focusing on the search for new bases of building strategic competitive advantage, not only to outperform competitors but to especially leapfrog them into new areas of competitive advantage. While the available results indicate that progress is being made on clarifying the nature and key dimensions of business models, relatively little guidance of how to reshape business models and its organizational fitness dimensions have emerged. This article presents a systemic framework for business model reinvention, illustrates its key dimensions, and proposes a systemic operationalization process. Moreover, it provides a tool that helps organizations to evaluate both existing and proposed new business models.

La Sirena decolonial: Lia La Novia y sus interrupciones afectivas

Este artículo examina las implicaciones y los significados creados en una pieza de sirena de Lia La Novia en la Universidad Nacional Autónoma de México en 2014 como parte de su serie Cuerpo en construcción. La sirena, una figura de la transgresión, ha tenido muchas versiones y variaciones, y Lia la encarna para cuestionar y reconfigurar las relaciones actuales de poder. Su “encuentro afectivo” requiere un análisis profundo, por los potenciales descolonizalidores que brinda esta acción, especialmente por sus usos de la mirada, la voz y los afectos. Analizo la(s) sirena(s) de Lia en relación con otras apariencias de las sirenas para poder entender mejor la carga de significado de su pieza. Lia logra, a través de ella, interrumpir en las violencias normativas y proponer una perspectiva decolonial, que posibilita otras maneras de ser y de aliarnos.This article examines the implications and meanings created in Lia La Novia's mermaid piece in the National Autonomous University of Mexico in 2014, a part of her “Cuerpo en Construcción” series. The mermaid, a transgressive figure, has had many versions and variations, and Lia embodies this figure to question and reconfigure current power relations. Her “affective encounter” requires an extensive analysis, because of the decolonizing potential that this action provides, especially because of her uses of the gaze, the voice, and affect. I analyze Lia's mermaid[s] to better understand the weight of meaning in her piece. Lia manages in this piece to interrupt in normative violence and propose a decolonial perspective, making other ways of being and forms of solidarity possible

VeraSun Corn Suppliers Must Respond to Preference Demand Letter by Sept. 30

Iowans who received payment for corn or other services from VeraSun within 90 days of the company’s filing for bankruptcy on Oct. 30, 2008 received preference demand letters at the end of August. The letters came from one of two New York law firms and demand that the supplier return a percent of the payments received from VeraSun during that 90-day period

Adaptation of Binaural Processing in the Adult Brainstem Induced by Ambient Noise

Interaural differences in stimulus intensity and timing are major cues for sound localization. In mammals, these cues are first processed in the lateral and medial superior olive by interaction of excitatory and inhibitory synaptic inputs from ipsi- and contralateral cochlear nucleus neurons. To preserve sound localization acuity following changes in the acoustic environment, the processing of these binaural cues needs neuronal adaptation. Recent studies have shown that binaural sensitivity adapts to stimulation history within milliseconds, but the actual extent of binaural adaptation is unknown. In the current study, we investigated long-term effects on binaural sensitivity using extracellular in vivo recordings from single neurons in the dorsal nucleus of the lateral lemniscus that inherit their binaural properties directly from the lateral and medial superior olives. In contrast to most previous studies, we used a noninvasive approach to influence this processing. Adult gerbils were exposed for 2 weeks to moderate noise with no stable binaural cue. We found monaural response properties to be unaffected by this measure. However, neuronal sensitivity to binaural cues was reversibly altered for a few days. Computational models of sensitivity to interaural time and level differences suggest that upregulation of inhibition in the superior olivary complex can explain the electrophysiological data