Optogenetic perturbations reveal the dynamics of an oculomotor integrator

Many neural systems can store short-term information in persistently firing neurons. Such persistent activity is believed to be maintained by recurrent feedback among neurons. This hypothesis has been fleshed out in detail for the oculomotor integrator (OI) for which the so-called “line attractor” network model can explain a large set of observations. Here we show that there is a plethora of such models, distinguished by the relative strength of recurrent excitation and inhibition. In each model, the firing rates of the neurons relax toward the persistent activity states. The dynamics of relaxation can be quite different, however, and depend on the levels of recurrent excitation and inhibition. To identify the correct model, we directly measure these relaxation dynamics by performing optogenetic perturbations in the OI of zebrafish expressing halorhodopsin or channelrhodopsin. We show that instantaneous, inhibitory stimulations of the OI lead to persistent, centripetal eye position changes ipsilateral to the stimulation. Excitatory stimulations similarly cause centripetal eye position changes, yet only contralateral to the stimulation. These results show that the dynamics of the OI are organized around a central attractor state—the null position of the eyes—which stabilizes the system against random perturbations. Our results pose new constraints on the circuit connectivity of the system and provide new insights into the mechanisms underlying persistent activity

Hardware and Control Implementation of Electric Springs for Stabilizing Future Smart Grid with Intermittent Renewable Energy Sources

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Modeling of poling, piezoelectric, and pyroelectric properties of ferroelectric 0-3 composites

Author name used in this publication: Y. T. OrAuthor name used in this publication: C. K. WongAuthor name used in this publication: B. PlossAuthor name used in this publication: F. G. Shin2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Polarization behavior of ferroelectric multilayered composite structures

Author name used in this publication: Y. T. OrAuthor name used in this publication: C. K. WongAuthor name used in this publication: B. PlossAuthor name used in this publication: F. G. Shin2002-2003 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Droop Control of Distributed Electric Springs for Stabilizing Future Power Grid

published_or_final_versio

Energy loss of monoenergetic positrons passing through a thin carbon foil

In this paper, the measurements of energy loss and energy loss straggling for 1-10 keV monoenergetic positrons passing through thin carbon foils of different thicknesses ranging from 1.0 to 5.0 μg/cm 2 are presented. The stopping power dE/dx and positron transmission coefficient as a function of incident positron energy and foil thickness have also been investigated. Particularly, the experimental results obtained are compared with those from Monte Carlo simulation and theory with a view to providing a way to determine the actual thickness of a carbon foil. The ratio of the energy straggling to the foil thickness seems to have a linear relation with the beam energy. © 2011 Elsevier B.V. All rights reserved.postprin

A Composite Method for Human Foot Structural Modeling

© 2015 The Authors A novel method including range-sensing scanning with texture and foot anatomical structure morphing basing on OpenSim is proposed. Palpation of important anatomical landmarks on foot surface was conducted by a physical therapist, and a range-sensing device, Microsoft Kinect sensor, was adopted for the 3D textured model acquisition. 3D coordinate data of the landmarks were measured and harnessed in OpenSim for subject-specific skeletal scaling based on a generic foot musculoskeletal model. The muscle attachment point coordinates derived from an anatomy database basing on sampling from East Asia people were used for muscle modelling. Then the 3D textured foot surface was registered with the morphed anatomical structures so that an integrated foot model was generated. The surface landmark locations were then compared with the corresponding internal bony sites and the errors were calculated to evaluate the accuracy and validity of this method. The potential error sources such as soft tissue thickness and scaling error were also mentioned and discussed. This technique is useful to create individual anatomically accurate human digital models for product design and development

Perceptions of leadership in undergraduate pharmacy students through a mixed methods study

Poster abstract from Conference; Royal Pharmaceutical Society Winter Summit 2017

Use of Hooke's law for stabilizing future smart grid - the electric spring concept

Hooke's law for mechanical springs was developed in the 17th century. Recently, new power electronics devices named electric springs have been developed for providing voltage regulation for distribution networks and allowing the load demand to follow power generation. This paper summarizes recent R&D on electric springs and their potential functions for future smart grid. Electric springs can be associated with electric appliances, forming a new generation of smart loads which can adapt according to the availability of power from renewable energy sources. When massively distributed over the power grid, they could provide highly distributed and robust support for the smart grid, similar to the arrays of mechanical springs supporting a mattress. Thus, the 3-century old Hooke's law in fact provides a powerful solution to solving some key Smart Grid problems in the 21st Century. © 2013 IEEE.published_or_final_versio