Design and Fabrication of a Three-Dimensional Multi-Electrode Array for Neuron Electrophysiology

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Lei Zuo ◽  
Shifeng Yu ◽  
Clark A. Briggs ◽  
Stanislaw Kantor ◽  
Jeffery Y. Pan
Keyword(s):  
Brain Slice ◽  
Three Dimensional ◽  
Field Potential ◽  
Electrode Array ◽  
Nerve Fibers ◽  
Field Potentials ◽  
Electrical Field ◽  
Hippocampus Slice ◽  
Neuron Electrophysiology ◽  
The Individual

Neural recording and stimulation with high spatial and temporal resolution are highly desirable in the study of neurocommunication and diseases. Planar multiple microelectrode arrays (MEA) or quasi-three-dimensional (3D) MEA with fixed height have been proposed by many researchers and become commercially available. In this paper, we present the design, fabrication, and test of a novel true 3D multiple electrode array for brain slice stimulation and recording. This MEA is composed of 105 microelectrodes with 50 μm diameter and 125 μm center-to-center spacing integrated in a 1.2 × 1.2 mm2 area. This “true” 3D MEA allows us to precisely position the individual electrodes by piezoelectric-based actuators to penetrate the inactive tissue layer and to approach the active neurons so as to optimize the recording and stimulation of electrical field potential. The capability to stimulate nerve fibers and record postsynaptic field potentials was demonstrated in an experiment using mouse brain hippocampus slice.

Presynaptic calcium dynamics at the frog retinotectal synapse

1996 ◽  
Vol 76 (1) ◽  
pp. 381-400 ◽  
Author(s):  
M. B. Feller ◽  
K. R. Delaney ◽  
D. W. Tank
Keyword(s):  
Optic Nerve ◽  
Action Potential ◽  
Optic Tectum ◽  
Field Potential ◽  
Nerve Fibers ◽  
Saturation Effect ◽  
Tetraacetic Acid ◽  
Field Potentials ◽  
Fura 2 ◽  
Fluorescence Transients

1. We characterized the kinetics of presynaptic Ca2+ ion concentration in optic nerve fibers and terminals of the optic tectum in Rana pipiens with the use of microfluorimetry. Isolated frog brains were incubated with the membrane-permeant tetraacetoxymethyl ester (AM) of the Ca2+ indicator fura-2. An optic nerve shock caused a transient decrease in the 380-nm excited fluorescence in the optic tectum with a rise time of <15 ms and a recovery to prestimulus levels on a time scale of seconds. 2. In normal saline, the amplitude of the fluorescence transients was dependent on stimulus intensity and at all levels it was directly correlated with the amplitude of postsynaptic field potentials produced by activation of unmyelinated optic nerve fibers. In the presence of the non-N-methyl-D-aspartate glutamate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione, the amplitude and time course of fluorescence transients remained essentially unchanged while postsynaptic field potential amplitude was greatly reduced. Replacing extracellular Ca2+ with Ba2+ blocked unfacilitated postsynaptic field potentials while fluorescence transients remained significant. In reduced-Ca2+ salines (<1 mM), the amplitude of fluorescence transients increased approximately linearly with extracellular [Ca2+], whereas the amplitude the corresponding field potential was nonlinearly related to the fluorescent transient amplitude (approximately 2.5 power). In thin sections of labeled tecta, fluorescence labeling was localized to 1-micron puncta in the termination zone of optic nerve fibers in the superficial layers. Taken together, these results provide strong evidence that the fluorescence transients correspond to an increase in Ca2+ in presynaptic terminals of unmyelinated optic nerve fibers. 3. During trains of optic nerve stimulation, the amplitude of fluorescence transients to succeeding action potentials became smaller. The decrement of the amplitudes was not observed in mag-fura-5-labeled tecta, when the intracellular Ca2+ buffering capacity of fura-2-labeled terminals was increased by incubation with bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid (BAPTA)-AM or ethylene glycol-bis (beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA)-AM, or in low-Ca2+ saline. We conclude that the Ca2+ influx per action potential is constant during the train and that the reduced response was produced by saturation of the fura-2. We provide a mathematical analysis of this saturation effect and use it to estimate the Ca2+ change per action potential. 4. Both BAPTA-AM and EGTA-AM reduced the overall amplitude of fura-2-measured Ca2+ transients and reduced the saturation effect in action potential trains. However, there was a qualitative difference in their effects on the shape of the transient. Incubation with the fast buffer BAPTA prolonged the decay to baseline. In contrast, the slow buffer EGTA (or EDTA) produced an initial decay faster than the control condition while also producing the slower subsequent phase observed with BAPTA. We demonstrate that these results are consistent with numerical simulations of Ca2+ dynamics in a single-compartment model where the fast initial decay is produced by the forward rate of Ca2+ binding to EGTA. 5. Ca2+ influx into tectal presynaptic structures, and also into unmyelinated axons in the isolated optic nerve, was diminished (60-70%) in the presence of the voltage-activated Ca2+ channel blocker omega-conotoxin GVIA, but was only weakly affected (approximately 10%) by omega-agatoxin IVA. 6. After 10- to 50-Hz stimulus trains, synaptic enhancement of unmyelinated fibers decayed with a characteristic time similar to fura-2 fluorescence decays. Incubation with EDTA-AM or EGTA-AM produced little effect on evoked release but reduced both the amplitude of the fura-2-measured Ca2+ transient and the amplitude of short-term synaptic enhancement.

Semi-automated methods for 3-D reconstruction of macromolecular complexes

1995 ◽  
Vol 53 ◽  
pp. 42-43
Author(s):  
B. Carragher ◽  
M. Whittaker
Keyword(s):  
Three Dimensional ◽  
Time Saving ◽  
Macromolecular Complexes ◽  
Symmetry Properties ◽  
Dimensional Reconstruction ◽  
Experienced Operator ◽  
Projection Images ◽  
The Individual ◽  
Natural Symmetry

Techniques for three-dimensional reconstruction of macromolecular complexes from electron micrographs have been successfully used for many years. These include methods which take advantage of the natural symmetry properties of the structure (for example helical or icosahedral) as well as those that use single axis or other tilting geometries to reconstruct from a set of projection images. These techniques have traditionally relied on a very experienced operator to manually perform the often numerous and time consuming steps required to obtain the final reconstruction. While the guidance and oversight of an experienced and critical operator will always be an essential component of these techniques, recent advances in computer technology, microprocessor controlled microscopes and the availability of high quality CCD cameras have provided the means to automate many of the individual steps.During the acquisition of data automation provides benefits not only in terms of convenience and time saving but also in circumstances where manual procedures limit the quality of the final reconstruction.

Phonetic iconicity in the evaluative morphology of a sample of Indo-European, Niger-Congo and Austronesian languages

2010 ◽  
Vol 3 (2) ◽  
pp. 156-180 ◽  
Author(s):  
Renáta Gregová ◽  
Lívia Körtvélyessy ◽  
Július Zimmermann
Keyword(s):  
Three Dimensional ◽  
Sound Symbolism ◽  
Three Dimensional Model ◽  
Austronesian Languages ◽  
Place Of Articulation ◽  
European Languages ◽  
Phonetic Symbolism ◽  
The Individual ◽  
Core Vocabulary

Universals Archive (Universal #1926) indicates a universal tendency for sound symbolism in reference to the expression of diminutives and augmentatives. The research ( Štekauer et al. 2009 ) carried out on European languages has not proved the tendency at all. Therefore, our research was extended to cover three language families – Indo-European, Niger-Congo and Austronesian. A three-step analysis examining different aspects of phonetic symbolism was carried out on a core vocabulary of 35 lexical items. A research sample was selected out of 60 languages. The evaluative markers were analyzed according to both phonetic classification of vowels and consonants and Ultan's and Niewenhuis' conclusions on the dominance of palatal and post-alveolar consonants in diminutive markers. Finally, the data obtained in our sample languages was evaluated by means of a three-dimensional model illustrating the place of articulation of the individual segments.

scholarly journals Modelling Polycrystalline Materials: An Overview of Three-Dimensional Grain-Scale Mechanical Models

2013 ◽  
Vol 05 (01) ◽  
pp. 1350002 ◽  
Author(s):  
I. Benedetti ◽  
F. Barbe
Keyword(s):  
Three Dimensional ◽  
Constitutive Modelling ◽  
Polycrystalline Materials ◽  
High Fidelity ◽  
Computational Capability ◽  
Mechanical Models ◽  
Three Dimensional Models ◽  
The Individual ◽  
Individual Grains ◽  
Micro Structures

A survey of recent contributions on three-dimensional grain-scale mechanical modelling of polycrystalline materials is given in this work. The analysis of material micro-structures requires the generation of reliable micro-morphologies and affordable computational meshes as well as the description of the mechanical behavior of the elementary constituents and their interactions. The polycrystalline microstructure is characterized by the topology, morphology and crystallographic orientations of the individual grains and by the grain interfaces and microstructural defects, within the bulk grains and at the inter-granular interfaces. Their analysis has been until recently restricted to two-dimensional cases, due to high computational requirements. In the last decade, however, the wider affordability of increased computational capability has promoted the development of fully three-dimensional models. In this work, different aspects involved in the grain-scale analysis of polycrystalline materials are considered. Different techniques for generating artificial micro-structures, ranging from highly idealized to experimentally based high-fidelity representations, are briefly reviewed. Structured and unstructured meshes are discussed. The main strategies for constitutive modelling of individual bulk grains and inter-granular interfaces are introduced. Some attention has also been devoted to three-dimensional multiscale approaches and some established and emerging applications have been discussed.

Dynamic coupling among neocortical neurons during evoked and spontaneous spike-wave seizure activity

1994 ◽  
Vol 72 (5) ◽  
pp. 2051-2069 ◽  
Author(s):  
M. Steriade ◽  
F. Amzica
Keyword(s):  
Cortical Neurons ◽  
Time Course ◽  
Early Stage ◽  
Field Potential ◽  
Time Lags ◽  
Temporal Relations ◽  
Intracellular Recordings ◽  
Field Potentials ◽  
Thalamic Nuclei ◽  
Spike Wave

1. We investigated the development from patterns of electroencephalogram (EEG) synchronization to paroxysms consisting of spike-wave (SW) complexes at 2–4 Hz or to seizures at higher frequencies (7–15 Hz). We used multisite, simultaneous EEG, extracellular, and intracellular recordings from various neocortical areas and thalamic nuclei of anesthetized cats. 2. The seizures were observed in 25% of experimental animals, all maintained under ketamine and xylazine anesthesia, and were either induced by thalamocortical volleys and photic stimulation or occurred spontaneously. Out of unit and field potential recordings within 370 cortical and 65 thalamic sites, paroxysmal events occurred in 70 cortical and 8 thalamic sites (approximately 18% and 12%, respectively), within which a total of 181 neurons (143 extracellular and 38 intracellular) were simultaneously recorded in various combinations of cell groups. 3. Stimulus-elicited and spontaneous SW seizures at 2–4 Hz lasted for 15–35 s and consisted of barrages of action potentials related to the spiky depth-negative (surface-positive) field potentials, followed by neuronal silence during the depth-positive wave component of SW complexes. The duration of inhibitory periods progressively increased during the seizure, at the expense of the phasic excitatory phases. 4. Intracellular recordings showed that, during such paroxysms, cortical neurons displayed a tonic depolarization (approximately 10–20 mV), sculptured by rhythmic hyperpolarizations. 5. In all cases, measures of synchrony demonstrated time lags between discharges of simultaneously recorded cortical neurons, from as short as 3–10 ms up to 50 ms or even longer intervals. Synchrony was assessed by cross-correlograms, by a method termed first-spike-analysis designed to detect dynamic temporal relations between neurons and relying on the detection of the first action potential in a spike train, and by a method termed sequential-field-correlation that analyzed the time course of field potentials simultaneously recorded from different cortical areas. 6. The degree of synchrony progressively increased from preseizure sleep patterns to the early stage of the SW seizure and, further, to its late stage. In some cases the time relation between neurons during the early stages of seizures was inversed during late stages. 7. These data show that, although the common definition of SW seizures, regarded as suddenly generalized and bilaterally synchronous activities, may be valid at the macroscopic EEG level, cortical neurons display time lags between their rhythmic spike trains, progressively increased synchrony, and changes in the temporal relations between their discharges during the paroxysms.(ABSTRACT TRUNCATED AT 400 WORDS)

Research on Generation Rules of Chest Width Point Curve Based on 3D Female Mannequin

2013 ◽  
Vol 796 ◽  
pp. 513-518
Author(s):  
Rong Jin ◽  
Bing Fei Gu ◽  
Guo Lian Liu
Keyword(s):  
Point Cloud ◽  
Three Dimensional ◽  
Upper Body ◽  
Secondary Development ◽  
Linear Regression Method ◽  
Point Cloud Data ◽  
Body Type ◽  
Cloud Data ◽  
Engineering Software ◽  
The Individual

In this paper 110 female undergraduates in Soochow University are measured by using 3D non-contact measurement system and manual measurement. 3D point cloud data of human body is taken as research objects by using anti-engineering software, and secondary development of point cloud data is done on the basis of optimizing point cloud data. In accordance with the definition of the human chest width points and other feature points, and in the operability of the three-dimensional point cloud data, the width, thickness, and length dimensions of the curve through the chest width point are measured. Classification of body type is done by choosing the ratio values as classification index which is the ratio between thickness and width of the curve. The generation rules of the chest curve are determined for each type by using linear regression method. Human arm model could be established by the computer automatically. Thereby the individual model of the female upper body mannequin modeling can be improved effectively.

A Numerically Efficient Method for Analysis of Very Large Articulated Floating Structures

1998 ◽  
Vol 42 (03) ◽  
pp. 174-186
Author(s):  
C. J. Garrison
Keyword(s):  
Hydrodynamic Interaction ◽  
Near Field ◽  
Three Dimensional ◽  
Computational Effort ◽  
Floating Structure ◽  
Complete Structure ◽  
Field Interaction ◽  
Floating Structures ◽  
Computing Effort ◽  
The Individual

A method is presented for evaluation of the motion of long structures composed of interconnected barges, or modules, of arbitrary shape. Such structures are being proposed in the construction of offshore airports or other large offshore floating structures. It is known that the evaluation of the motion of jointed or otherwise interconnected modules which make up a long floating structure may be evaluated by three dimensional radiation/diffraction analysis. However, the computing effort increases rapidly as the complexity of the geometric shape of the individual modules and the total number of modules increases. This paper describes an approximate method which drastically reduces the computational effort without major effects on accuracy. The method relies on accounting for hydrodynamic interaction effects between only adjacent modules within the structure rather than between all of the modules since the near-field interaction is by far the more important. This approximation reduces the computational effort to that of solving the two-module problem regardless of the total number of modules in the complete structure.

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