Large-scale changes in cortical dynamics triggered by repetitive somatosensory electrical stimulation.

BackgroundRepetitive somatosensory electrical stimulation (SES) of forelimb peripheral nerves is a promising therapy; studies have shown that SES can improve motor function in stroke subjects with chronic deficits. However, little is known about how SES can directly modulate neural dynamics. Past studies using SES have primarily used noninvasive methods in human subjects. Here we used electrophysiological recordings from the rodent primary motor cortex (M1) to assess how SES affects neural dynamics at the level of single neurons as well as at the level of mesoscale dynamics.MethodsWe performed acute extracellular recordings in 7 intact adult Long Evans rats under ketamine-xylazine anesthesia while they received transcutaneous SES. We recorded single unit spiking and local field potentials (LFP) in the M1 contralateral to the stimulated arm. We then compared neural firing rate, spike-field coherence (SFC), and power spectral density (PSD) before and after stimulation.ResultsFollowing SES, the firing rate of a majority of neurons changed significantly from their respective baseline values. There was, however, a diversity of responses; some neurons increased while others decreased their firing rates. Interestingly, SFC, a measure of how a neuron's firing is coupled to mesoscale oscillatory dynamics, increased specifically in the δ-band, also known as the low frequency band (0.3- 4 Hz). This increase appeared to be driven by a change in the phase-locking of broad-spiking, putative pyramidal neurons. These changes in the low frequency range occurred without a significant change in the overall PSD.ConclusionsRepetitive SES significantly and persistently altered the local cortical dynamics of M1 neurons, changing both firing rates as well as the SFC magnitude in the δ-band. Thus, SES altered the neural firing and coupling to ongoing mesoscale dynamics. Our study provides evidence that SES can directly modulate cortical dynamics

S and Q Matrices Reloaded: applications to open, inhomogeneous, and complex cavities

We present a versatile numerical algorithm for computing resonances of open dielectric cavities. The emphasis is on the generality of the system's configuration, i.e. the geometry of the (main) cavity (and possible inclusions) and the internal and external dielectric media (homogeneous and inhomogeneous). The method is based on a scattering formalism to obtain the position and width of the (quasi)-eigenmodes. The core of the method lies in the scattering S-matrix and its associated delay Q-matrix which contain all the relevant information of the corresponding scattering experiment. For instance, the electromagnetic near- and far-fields are readily extracted. The flexibility of the propagation method is displayed for a selected system.Comment: 15th International Conference on Transparent Optical Networks (2013

Phase Space Engineering in Optical Microcavities I: Preserving near-field uniformity while inducing far-field directionality

Optical microcavities have received much attention over the last decade from different research fields ranging from fundamental issues of cavity QED to specific applications such as microlasers and bio-sensors. A major issue in the latter applications is the difficulty to obtain directional emission of light in the far-field while keeping high energy densities inside the cavity (i.e. high quality factor). To improve our understanding of these systems, we have studied the annular cavity (a dielectric disk with a circular hole), where the distance cavity-hole centers, d, is used as a parameter to alter the properties of cavity resonances. We present results showing how one can affect the directionality of the far-field while preserving the uniformity (hence the quality factor) of the near-field simply by increasing the value of d. Interestingly, the transition between a uniform near- and far-field to a uniform near- and directional far-field is rather abrupt. We can explain this behavior quite nicely with a simple model, supported by full numerical calculations, and we predict that the effect will also be found in a large class of eigenmodes of the cavity.Comment: 12th International Conference on Transparent Optical Network

Ameiva corax

Number of Pages: 2Integrative BiologyGeological Science

Complexity Measures of Music

We present a technique to search for the presence of crucial events in music, based on the analysis of the music volume. Earlier work on this issue was based on the assumption that crucial events correspond to the change of music notes, with the interesting result that the complexity index of the crucial events is mu ~ 2, which is the same inverse power-law index of the dynamics of the brain. The search technique analyzes music volume and confirms the results of the earlier work, thereby contributing to the explanation as to why the brain is sensitive to music, through the phenomenon of complexity matching. Complexity matching has recently been interpreted as the transfer of multifractality from one complex network to another. For this reason we also examine the mulifractality of music, with the observation that the multifractal spectrum of a computer performance is significantly narrower than the multifractal spectrum of a human performance of the same musical score. We conjecture that although crucial events are demonstrably important for information transmission, they alone are not suficient to define musicality, which is more adequately measured by the multifractality spectrum

EFFECTS OF CHIGGER MITE (ACARI: TROMBICULIDAE) INFECTIONS ON AMEIVA (SQUAMATA: TEIIDAE) FROM THE ANGUILLA BANK

We examined 152 Ameiva plei from four sites on Anguilla and from Scrub Island, a nearby satellite, and 12 A. corax from Little Scrub Island, another Anguillian satellite, generated indices of condition by dividing mass (g) by SVL (mm), and quantified degrees of eutrombiculid chigger mite infections by measuring the total areas (mm2) of each lizard covered by one or more clusters of mites. Prevalence in infected A. plei (N = 77) varied significantly by site, but frequencies of infected males and females within sites did not differ signifi cantly. Indices of condition of infected and mite-free lizards did not differ significantly, nor was area covered by mites significantly correlated with condition, suggesting that mite infections are relatively asymptomatic. All Ameiva corax were infected, and area covered by mites was not significantly correlated with condition. Indices of condition for A. corax were signifi cantly lower than for infected A. plei, probably refl ecting the poorer condition of lizards occupying a food-deficient habitat

NASA Ames Institutional Scientific Collection (ISC)

NASA's current human space flight research is directed towards enabling human space exploration beyond Low Earth Orbit (LEO). The Space Flight Payload Projects; Rodent Research, Cell Science, and Microbial Labs, flown on the International Space Station (ISS), benefit both the global life sciences and commercial space communities. Verified data sets, science results, peer-reviewed publications, and returned biospecimens, collected and analyzed for flight and ground investigations, are all part of the knowledge base within NASAs Human Exploration and Operations Mission Directorates Space Life and Physical Sciences Research and Applications (SLPSRA) Division, specifically the Human Research and Space Biology Programs. These data and biospecimens are made available through the public LSDA website. The Ames Institutional Scientific Collection (ISC), or ARC Biobank, stores flight and ground biospecimens from Space Shuttle and ISS programs. These specimens are curated and managed by the Ames Life Sciences Data Archive (ALSDA), an internal node of NASA's Life Sciences Data Archive (LSDA). The ARC Biolbank stores over 15,000 specimens from experiments dating from 1984 to present. Currently available specimens include tissues from the circulatory, digestive, endocrine, excretory, integumentary, muscular, neurosensory, reproductive, respiratory and skeletal systems. The most recent contributions include RNA, DNA and protein extracts from Rodent Research 1 and tissues from Rodent Research 4. NASA's biospecimen collection represents a unique and limited resource. The use of these biospecimens maximizes utilization and scientific return from these unique spaceflight payload and ground control research subjects. These biospecimens are harvested following complex, costly NASA research activities to meet primary scientific objectives. Once the primary scientific objectives have been met, the remaining specimens are made available to provide secondary opportunities for complementary studies or new investigations to broaden research without large expenditures of time or resources. Innovative ways of sharing this information ultimately advances the frontiers of human space exploration as well as scientific understanding of the effects of gravity on life on earth

Practical and Theoretical Underpinnings of INFFER (Investment Framework For Environmental Resources)

INFFER (Investment Framework for Environmental Resources) was developed to help investors of public funds to improve the delivery of outcomes from environmental programs. It assists environmental managers to design projects, to select delivery mechanisms, and to rank competing projects on the basis of benefits and costs. The design of INFFER and the activities of the INFFER projects are based on extensive experience of working with environmental managers and policy makers. This experience has highlighted a number of important practical lessons, that have strongly influenced the design and implementation of INFFER. These lessons include the need for simplicity, training and support of users, trusting relationships with users, transparency, flexibility, compatibility with the needs and contexts of users, and supportive institutional arrangements. In additions, the developers have paid close attention to the need for processes that are theoretically rigorous, resulting in a tool that deals appropriately and consistently with projects for different assets types, of different scales and durations, consistent with Benefit: Cost Analysis. The paper outlines theoretical considerations underpinning the way that INFFER deals with asset valuation, time lags, uncertainty, and the design of the metric used to rank projects.Environmental Economics and Policy,

Lessons from implementing INFFER with regional catchment management organisations

Investment in natural resource management (NRM) by regional organisations in Australia has been widely criticised for failing to achieve substantial environmental outcomes. The Investment Framework for Environmental Resources (INFFER) is a tool for developing and prioritising projects to address environmental issues such as water quality and biodiversity decline, environmental pest impacts and land degradation. It aims to achieve the most valuable environmental outcomes with the available resources. During 2008 and 2009 INFFER has been implemented with a number of catchment management organisations (CMOs) throughout Australia. In this paper, we report on lessons from and implications of this experience. Data on implementation were collected in formal and informal ways from staff of organisations that were using INFFER and state agencies, including: an on-line survey, benchmarking questions at training workshops, a formal on-going monitoring and evaluation process tracking the use of INFFER by CMOs, and comments made in correspondence and informal feedback to the INFFER team. In this paper we describe issues that arise when implementing INFFER with regions and organisations, and how the INFFER team has attempted to address these. Key issues include a desire to consider the community as an asset and emphasise capacity building, a rejection of the need for targeted investment, and various difficulties associated with specific aspects of the Framework. Existing institutional arrangements, and the legacy of past institutional arrangements, remain serious barriers to the adoption of methods to improve environmental outcomes from NRM investment. A lack of rigour in investment planning has become accepted as the norm, and resistance to processes to improve rigour is common. However, many CMOs want to achieve better environmental outcomes with their limited funds, and we report on our efforts to work with them to achieve this by using INFFER.Research and Development/Tech Change/Emerging Technologies,