Name: optical recording of suprathreshold neural activity with single-cell and single-spike resolution
Uploaded: 2012-09-05T12:00:00
Description: Watch this Scientific Journal Video about Optical Recording of Suprathreshold Neural Activity with Single-cell and Single-spike Resolution at JoVE.com

Vi takker Dr. Randy Chitwood for kritisk læsning af manuskriptet. Dette arbejde blev støttet af Whitehall Foundation og Alfred P. Sloan Foundation tilskud til HJK.

1. Optiske opstilling (fig. 1) <ol><li> For to-foton excitering en infrarød pulseret laser system med femtosekund pulser anvendes. En høj laser udgangseffekt (i nogle tilfælde&gt; 2W ved 890 nm bølgelængde) er forpligtet til at udligne de store tab indført ved de optiske komponenter i systemet. </li><li> Et prechirper bestående af to prismer bibringer en negativ gruppehastighed dispersion (GVD) på de laserimpulser inden de akustooptiske deflektorer (AODs) for at kompensere for den tidsmæssige dispersion indf?...

<ol>
	<li>Iyer, V., Hoogland, T. M., Saggau, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fast+functional+imaging+of+single+neurons+using+random-access+multiphoton+(RAMP)+microscopy.">Fast functional imaging of single neurons using random-access multiphoton (RAMP) microscopy.</a> J. Neurophysiol. 95, 535-545 (2006).</li><li>Denk, W., Strickler, J. H., Webb, W. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-photon+laser+scanning+fluorescence+microscopy.">Two-photon laser scanning fluorescence microscopy.</a> Science. 248, 73 (1990).</li><li>Ranganathan, G. N., Koester, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optical+recording+of+neuronal+spiking+activity+from+unbiased+populations+of+neurons+with+high+spike+detection+efficiency+and+high+temporal+precision.">Optical recording of neuronal spiking activity from unbiased populations of neurons with high spike detection efficiency and high temporal precision.</a> J. Neurophysiol. 104, 1812-1824 (2010).</li><li>Grewe, B. F., Langer, D., Kasper, H., Kampa, B. M., Helmchen, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-speed+in+vivo+calcium+imaging+reveals+neuronal+network+activity+with+near-millisecond+precision.">High-speed in vivo calcium imaging reveals neuronal network activity with near-millisecond precision.</a> Nat. 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N., Greenberg, D., Helmchen, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+input+and+output+of+neocortical+networks+in+vivo.">Imaging input and output of neocortical networks in vivo.</a> Proc. Natl. Acad. Sci. U.S.A. 102, 14063-14068 (2005).</li><li>Lin, B. J., Chen, T. W., Schild, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+type-specific+relationships+between+spiking+and+[Ca2+]i+in+neurons+of+the+Xenopus+tadpole+olfactory+bulb.">Cell type-specific relationships between spiking and [Ca2+]i in neurons of the Xenopus tadpole olfactory bulb.</a> J. Physiol. 582, 163-175 (2007).</li><li>Zeng, S., Lv, X., Zhan, C., Chen, W. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+compensation+for+spatial+and+temporal+dispersion+of+acousto-optical+deflectors+for+two-dimensional+scanning+with+a+single+prism.">Simultaneous compensation for spatial and temporal dispersion of acousto-optical deflectors for two-dimensional scanning with a single prism.</a> Opt. Lett. 31, 1091-1093 (2006).</li><li>Otsu, Y., Bormuth, V., Wong, J., Mathieu, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optical+monitoring+of+neuronal+activity+at+high+frame+rate+with+a+digital+random-access+multiphoton+(RAMP)+microscope.">Optical monitoring of neuronal activity at high frame rate with a digital random-access multiphoton (RAMP) microscope.</a> J. Neurosci. Methods. 173, 259-270 (2008).</li><li>Vogelstein, J. T., Watson, B. O., Packer, A. M., Yuste, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spike+inference+from+calcium+imaging+using+sequential+Monte+Carlo+methods.">Spike inference from calcium imaging using sequential Monte Carlo methods.</a> Biophys. J. 97, 636-655 (2009).</li><li>Yaksi, E., Friedrich, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reconstruction+of+firing+rate+changes+across+neuronal+populations+by+temporally+deconvolved+Ca2++imaging.">Reconstruction of firing rate changes across neuronal populations by temporally deconvolved Ca2+ imaging.</a> Nat. Methods. 3, 377-383 (2006).</li><li>Hendel, T., Mank, M., Schnell, B., Griesbeck, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescence+changes+of+genetic+calcium+indicators+and+OGB-1+correlated+with+neural+activity+and+calcium+in+vivo+and+in+vitro.">Fluorescence changes of genetic calcium indicators and OGB-1 correlated with neural activity and calcium in vivo and in vitro.</a> J. Neurosci. 28, 7399-7411 (2008).</li><li>Ranganathan, G. N., Koester, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlations+decrease+with+propagation+of+spiking+activity+in+the+mouse+barrel+cortex.">Correlations decrease with propagation of spiking activity in the mouse barrel cortex.</a> Front Neural Circuits. 5, 8 (2011).</li></ol>

Dithered random-access-scanning indirekte registrerer suprathreshold spiking aktivitet fra stigningerne i intracellulær somatisk calcium forbundet med hver stigning i et neuron somata. De stigninger i intracellulært calcium påvises ved fluorescerende calcium farvestoffer. Begrænsningerne ved dithered random-access-scanning skyldes i stor udstrækning af den begrænsede signal-støj-forholdet for calcium-fluorescenssignaler. The signal-støj-forhold er igen begrænset af lysbeskadigelse, som ikke tillader anvendelse ...

<table border="1"><tbody><tr><td> Navn på reagenset </td><td> Firma </td><td> Katalognummer </td><td> Kommentarer (valgfrit) </td></tr><tr><td></td><td></td><td></td><td> Optiske komponenter er vist i rækkefølge, startende fra laseren </td></tr><tr><td> Titan: Sapphire Laser </td><td> Sammenhængende Inc. </td><td> Chameleon Ultra 2 </td><td> Høj udgangseffekt anbefales (&gt; 2 W ved 900 nm) </td></tr><tr><td> Akromatisk linse f = 30 mm </td><td> Thor labs </td><td> AC254-030-B </td><td> Anti-reflekterende (AR) belægning for 650-1050 nm </td></tr><tr><td> Akromatisk linse f = 100 mm </td><td> Thor labs </td><td> AC254-100-B </td><td> AR 650-1050 nm </td></tr><tr><td> Objektiv F = 75 mm </td><td> Thor labs </td><td> LA1608-B </td><td> AR 650-1050 nm </td></tr><tr><td> Objektiv F = 175 mm</td><td> Thor labs </td><td> LA1229-B </td><td> AR 650-1050 nm </td></tr><tr><td> Akromatisk linse f = 300 mm </td><td> Thor labs </td><td> AC254-300-B </td><td> AR 650-1050 nm </td></tr><tr><td> Akromatisk linse f = 100 mm </td><td> Thor labs </td><td> AC254-100-B </td><td> AR 650-1050 nm </td></tr><tr><td> Akromatisk linse f = 100 mm </td><td> Thor labs </td><td> AC254-100-B </td><td> AR 650-1050 nm </td></tr><tr><td> Akustooptiske deflektorer </td><td> Intraaction Corp </td><td> ATD 6510CD2 </td><td></td></tr><tr><td> Reflekterende diffraktionsgitter </td><td> Newport </td><td> 53-011R </td><td> 100 riller / mm til AODs med 65 MHz båndbredde og scan vinkel på 45 mrad </td></tr><tr><td> 21,6 mm Brewster prismer </td><td> Lambda Research Optics Inc. </td><td> IBP21.6SF10 </td><td></td></tr><tr><td> Farvet glas </td><td> Schott </td&gt; <td> BG-39 </td><td></td></tr><tr><td> Dichroisk spejl </td><td> Chroma Technology Corp </td><td> Z532RDC </td><td></td></tr><tr><td> Fotomultiplikatorrør moduler </td><td> Hamamatsu </td><td> H9305-03 </td><td></td></tr><tr><td> DAC-ADC board </td><td> National Instruments </td><td> PCI-6115 </td><td></td></tr><tr><td> Oregon Green 488 BAPTA-1:00 </td><td> Invitrogen </td><td> O-6807 </td><td></td></tr></tbody></table>

optical recording of suprathreshold neural activity with single-cell and single-spike resolution

Signalering af oplysninger i hvirveldyr centrale nervesystem er ofte båret af populationer af neuroner snarere end individuelle neuroner. Også udbredelsen af ​​suprathreshold spiking aktivitet indebærer populationer af neuroner. Empiriske undersøgelser vedrørende cortical funktion direkte derfor kræver optagelser fra populationer af neuroner med høj opløsning. Her beskriver vi en optisk metode og en dekonvolution algoritme til at optage neurale aktivitet fra op til 100 neuroner med enkelt-celle-og single-spike opløsning. Denne metode er baseret på påvisning af forbigående stigninger i intracellulær somatisk calciumkoncentration forbundet med suprathreshold elektriske pigge (aktionspotentialer) i kortikale neuroner. Høj tidsmæssig opløsning af de optiske optagelser opnås ved en hurtig random-access-scanning, hvor der anvendes akustooptiske deflektorer (AODs) 1. To-foton excitation af calcium-sensitive farvestof resulterer i høj rumlig opløsning i uigennemsigtige hjerne tissagsøge 2. Rekonstruktion af spidserne fra den fluorescens calcium optagelser opnås ved en maksimal sandsynlighed-metode. Samtidige elektrofysiologiske og optiske optagelser viser, at vores metode pålideligt detekterer spikes (&gt; 97% spike afsløring effektivitet), har en lav falsk positiv spike detektion (&lt;0,003 spikes / s), og en stor tidsmæssig præcision (ca. 3 ms) 3. Denne optiske fremgangsmåde til spike detektion kan anvendes til at registrere neurale aktivitet in vitro og in bedøvede dyr in vivo 3,4.

Watch this Scientific Journal Video about Optical Recording of Suprathreshold Neural Activity with Single-cell and Single-spike Resolution at JoVE.com

Optical Recording of Suprathreshold Neural Activity with Single-cell and Single-spike Resolution

Forstå funktionen af ​​hvirveldyr centralnervesystemet kræver optagelser fra mange neuroner, fordi cortical funktion opstår ved størrelsen af ​​populationer af neuroner. Her beskriver vi en optisk metode til at registrere suprathreshold neurale aktivitet med enkelt-celle-og single-spike opløsning, dithered random-access-scanning. Denne metode optegnelser somatiske fluorescens calcium-signaler fra op til 100 neuroner med høj tidsopløsning. En maksimal-sandsynlighed algoritme deconvolves den underliggende suprathreshold neurale aktivitet fra de somatiske fluorescens calcium signaler. Denne metode detekterer spikes med høj detektion effektivitet og en lav falsk positive og kan anvendes til at studere neurale populationer<em&gt; In vitro</em&gt; Og<em&gt; In vivo</em&gt;.

Optisk registrering af suprathreshold neurale aktivitet med enkelt-celle-og single-spike opløsning

Signaling of information in the vertebrate central nervous system is often carried by populations of neurons rather than individual neurons. Also ...

optical-recording-suprathreshold-neural-activity-with-single-cell

Research

JoVE Journal

Neuroscience

Surgical Implantation of Chronic Neural Electrodes for Recording Single Unit Activity and Electrocorticographic Signals

The success of long-term electrophysiological recordings often depends on the quality of the implantation surgery. Here we provide useful information for surgeons who are learning the process of implanting electrode systems. We demonstrate the implantation procedure of both a penetrating and a surface electrode. The surgical process is described from start to finish, including detailed descriptions of each step throughout the procedure. It should also be noted that this video guide is focused towards procedures conducted in rodent models and other small animal models. Modifications of the described procedures are feasible for other animal models.

We provide useful information for surgeons who are learning the process of implanting chronic neural recording electrodes. Techniques for both penetrating and surface electrode systems are described in a rodent animal model.

Kirurgisk implantation af Kroniske Neurale elektroder til Optagelse Single Unit Aktivitet og Electrocorticographic signaler

The success of long-term electrophysiological recordings often depends on the quality of the implantation surgery.  Here we provide useful information for ...

Multi-unit Recording Methods to Characterize Neural Activity in the Locust (Schistocerca Americana) Olfactory Circuits

Detection and interpretation of olfactory cues are critical for the survival of many organisms. Remarkably, species across phyla have strikingly similar olfactory systems suggesting that the biological approach to chemical sensing has been optimized over evolutionary time1. In the insect olfactory system, odorants are transduced by olfactory receptor neurons (ORN) in the antenna, which convert chemical stimuli into trains of action potentials. Sensory input from the ORNs is then relayed to the antennal lobe (AL; a structure analogous to the vertebrate olfactory bulb). In the AL, neural representations for odors take the form of spatiotemporal firing patterns distributed across ensembles of principal neurons (PNs; also referred to as projection neurons)2,3. The AL output is subsequently processed by Kenyon cells (KCs) in the downstream mushroom body (MB), a structure associated with olfactory memory and learning4,5. Here, we present electrophysiological recording techniques to monitor odor-evoked neural responses in these olfactory circuits.
First, we present a single sensillum recording method to study odor-evoked responses at the level of populations of ORNs6,7. We discuss the use of saline filled sharpened glass pipettes as electrodes to extracellularly monitor ORN responses. Next, we present a method to extracellularly monitor PN responses using a commercial 16-channel electrode3. A similar approach using a custom-made 8-channel twisted wire tetrode is demonstrated for Kenyon cell recordings8. We provide details of our experimental setup and present representative recording traces for each of these techniques.

Multi-unit Recording Methods to Characterize Neural Activity in the Locust Schistocerca Americana Olfactory Circuits

We demonstrate variations of the extracellular multi-unit recording technique to characterize odor-evoked responses in the first three stages of the invertebrate olfactory pathway. These techniques can easily be adapted to examine ensemble activity in other neural systems as well.

Multi-unit Optagelse metoder til karakterisering af neurale aktivitet i Locust (<em&gt; Schistocerca Americana</em&gt;) Lugtesansen Circuits

Detection and interpretation of olfactory cues are critical for the survival  of many organisms. Remarkably, species across phyla have strikingly similar ...

Optogenetic Perturbation of Neural Activity with Laser Illumination in Semi-intact Drosophila Larvae in Motion

Drosophila larval locomotion is a splendid model system in developmental and physiological neuroscience, by virtue of the genetic accessibility of the underlying neuronal components in the circuits1-6. Application of optogenetics7,8 in the larval neural circuit allows us to manipulate neuronal activity in spatially and temporally patterned ways9-13. Typically, specimens are broadly illuminated with a mercury lamp or LED, so specificity of the target neurons is controlled by binary gene expression systems such as the Gal4-UAS system14,15. In this work, to improve the spatial resolution to "sub-genetic resolution", we locally illuminated a subset of neurons in the ventral nerve cord using lasers implemented in a conventional confocal microscope. While monitoring the motion of the body wall of the semi-intact larvae, we interactively activated or inhibited neural activity with channelrhodopsin16,17 or halorhodopsin18-20, respectively. By spatially and temporally restricted illumination of the neural tissue, we can manipulate the activity of specific neurons in the circuit at a specific phase of behavior. This method is useful for studying the relationship between the activities of a local neural assembly in the ventral nerve cord and the spatiotemporal pattern of motor output.

Optogenetic Perturbation of Neural Activity with Laser Illumination in Semi-intact Drosophila Larvae in Motion

Here we describe a protocol for optogenetic manipulation of motoneuronal activity while monitoring changes in motor output (muscle contraction) in semi-intact Drosophila larvae using lasers within a conventional confocal microscope. This technique enables researchers to achieve local perturbation of neural activity in a few neuromeres to elucidate the dynamics of motor circuits.

Optogenetic forstyrrelse af neurale aktivitet med laserbelysning i Semi-intakt<em&gt; Drosophila</em&gt; Larver in Motion

Drosophila larval locomotion is a splendid model system in developmental and physiological neuroscience, by virtue of the genetic accessibility of the ...

Micron-scale Resolution Optical Tomography of Entire Mouse Brains with Confocal Light Sheet Microscopy

Understanding the architecture of mammalian brain at single-cell resolution is one of the key issues of neuroscience. However, mapping neuronal soma and projections throughout the whole brain is still challenging for imaging and data management technologies. Indeed, macroscopic volumes need to be reconstructed with high resolution and contrast in a reasonable time, producing datasets in the TeraByte range. We recently demonstrated an optical method (confocal light sheet microscopy, CLSM) capable of obtaining micron-scale reconstruction of entire mouse brains labeled with enhanced green fluorescent protein (EGFP). Combining light sheet illumination and confocal detection, CLSM allows deep imaging inside macroscopic cleared specimens with high contrast and speed. Here we describe the complete experimental pipeline to obtain comprehensive and human-readable images of entire mouse brains labeled with fluorescent proteins. The clearing and the mounting procedures are described, together with the steps to perform an optical tomography on its whole volume by acquiring many parallel adjacent stacks. We showed the usage of open-source custom-made software tools enabling stitching of the multiple stacks and multi-resolution data navigation. Finally, we illustrated some example of brain maps: the cerebellum from an L7-GFP transgenic mouse, in which all Purkinje cells are selectively labeled, and the whole brain from a thy1-GFP-M mouse, characterized by a random sparse neuronal labeling.

In this article we describe the full experimental procedure to reconstruct, with high resolution, the fine brain anatomy of fluorescently labeled mouse brains. The described protocol includes sample preparation and clearing, specimen mounting for imaging, data post-processing and multi-scale visualization.

Micron-skala Opløsning Optical Tomography af hele Mouse Brains med konfokal Light Sheet Microscopy

Understanding the architecture of mammalian  brain at single-cell resolution is one of the key issues of neuroscience.  However, mapping neuronal soma and ...

Neural Activity Propagation in an Unfolded Hippocampal Preparation with a Penetrating Micro-electrode Array

This protocol describes a method for preparing a new in vitro flat hippocampus preparation combined with a micro-machined array to map neural activity in the hippocampus. The transverse hippocampal slice preparation is the most common tissue preparation to study hippocampus electrophysiology. A longitudinal hippocampal slice was also developed in order to investigate longitudinal connections in the hippocampus. The intact mouse hippocampus can also be maintained in vitro because its thickness allows adequate oxygen diffusion. However, these three preparations do not provide direct access to neural propagation since some of the tissue is either missing or folded. The unfolded intact hippocampus provides both transverse and longitudinal connections in a flat configuration for direct access to the tissue to analyze the full extent of signal propagation in the hippocampus in vitro. In order to effectively monitor the neural activity from the cell layer, a custom made penetrating micro-electrode array (PMEA) was fabricated and applied to the unfolded hippocampus. The PMEA with 64 electrodes of 200 &#181;m in height could record neural activity deep inside the mouse hippocampus. The unique combination of an unfolded hippocampal preparation and the PMEA provides a new in-vitro tool to study the speed and direction of propagation of neural activity in the two-dimensional CA1-CA3 regions of the hippocampus with a high signal to noise ratio.

We have developed an in vitro unfolded hippocampus which preserves CA1-CA3 array of neurons. Combined with the penetrating micro-electrode array, neural activity can be monitored in both the longitudinal and transverse orientations. This method provides advantages over hippocampal slice preparations as the propagation in the entire hippocampus can be recorded simultaneously.

Neurale aktivitet Propagation i en udfoldet Hippocampal Forberedelse med en gennemtrængende Micro-elektrode Array

This protocol describes a method for preparing a new in vitro flat hippocampus preparation combined with a micro-machined array to map neural activity in ...

Extracellular Recording of Neuronal Activity Combined with Microiontophoretic Application of Neuroactive Substances in Awake Mice

Differences in the activity of neurotransmitters and neuromodulators, and consequently different neural responses, can be found between anesthetized and awake animals. Therefore, methods allowing the manipulation of synaptic systems in awake animals are required in order to determine the contribution of synaptic inputs to neuronal processing unaffected by anesthetics. Here, we present methodology for the construction of electrodes to simultaneously record extracellular neural activity and release multiple neuroactive substances at the vicinity of the recording sites in awake mice. By combining these procedures, we performed microiontophoretic injections of gabazine to selectively block GABAA receptors in neurons of the inferior colliculus of head-restrained mice. Gabazine successfully modified neural response properties such as the frequency response area and stimulus-specific adaptation. Thus, we demonstrate that our methods are suitable for recording single-unit activity and for dissecting the role of specific neurotransmitter receptors in auditory processing.
The main limitation of the described procedure is the relatively short recording time (~3 hr), which is determined by the level of habituation of the animal to the recording sessions. On the other hand, multiple recording sessions can be performed in the same animal. The advantage of this technique over other experimental procedures used to manipulate the level of neurotransmission or neuromodulation (such as systemic injections or the use of optogenetic models), is that the drug effect is confined to the local synaptic inputs to the target neuron. In addition, the custom-manufacture of electrodes allows adjustment of specific parameters according to the neural structure and type of neuron of interest (such as the tip resistance for improving the signal-to-noise ratio of the recordings).

We present methods for the construction of electrodes to simultaneously record extracellular neural activity and release multiple neuroactive substances at the vicinity of the recording sites in awake mice. This technique allows the detailed analysis of putative local synaptic inputs to the neuron of interest.

Ekstracellulær Registrering af neuronal aktivitet Kombineret med Microiontophoretic Anvendelse af Neuroaktive stoffer i Awake mus

Differences in the activity of neurotransmitters and neuromodulators, and consequently different neural responses, can be found between anesthetized and ...

Fabrication of High Contact-Density, Flat-Interface Nerve Electrodes for Recording and Stimulation Applications

Many attempts have been made to manufacture multi-contact nerve cuff electrodes that are safe, robust and reliable for long term neuroprosthetic applications. This protocol describes a fabrication technique of a modified cylindrical nerve cuff electrode to meet these criteria. Minimum computer-aided design and manufacturing (CAD and CAM) skills are necessary to consistently produce cuffs with high precision (contact placement 0.51 &#177; 0.04 mm) and various cuff sizes. The precision in spatially distributing the contacts and the ability to retain a predefined geometry accomplished with this design are two criteria essential to optimize the cuff&#39;s interface for selective recording and stimulation. The presented design also maximizes the flexibility in the longitudinal direction while maintaining sufficient rigidity in the transverse direction to reshape the nerve by using materials with different elasticities. The expansion of the cuff&#39;s cross sectional area as a result of increasing the pressure inside the cuff was observed to be 25% at 67 mm Hg. This test demonstrates the flexibility of the cuff and its response to nerve swelling post-implant. The stability of the contacts&#39; interface and recording quality were also examined with contacts&#39; impedance and signal-to-noise ratio metrics from a chronically implanted cuff (7.5 months), and observed to be 2.55 &#177; 0.25 k&#8486; and 5.10 &#177; 0.81 dB respectively.

This article provides a detailed description on the fabrication process of a high contact-density flat interface nerve electrode (FINE). This electrode is optimized for recording and stimulating neural activity selectively within peripheral nerves.

Fabrikation af High Kontakt-Density, Fladskærms-interface Nerve Elektroder til Optagelse og Stimulation Applications

Many attempts have been made to manufacture multi-contact nerve cuff electrodes that are safe, robust and reliable for long term neuroprosthetic ...

Single-cell Resolution Fluorescence Live Imaging of Drosophila Circadian Clocks in Larval Brain Culture

The circadian pacemaker circuit orchestrates rhythmic behavioral and physiological outputs coordinated with environmental cues, such as day/night cycles. The molecular clock within each pacemaker neuron generates circadian rhythms in gene expression, which underlie the rhythmic neuronal functions essential to the operation of the circuit. Investigation of the properties of the individual molecular oscillators in different subclasses of pacemaker neurons and their interaction with neuronal signaling yields a better understanding of the circadian pacemaker circuit. Here, we present a time-lapse fluorescent microscopy approach developed to monitor the molecular clockwork in clock neurons of cultured Drosophila larval brain. This method allows the multi-day recording of the rhythms of genetically encoded fluorescent circadian reporters at single-cell resolution. This setup can be combined with pharmacological manipulations to closely analyze real-time response of the molecular clock to various compounds. Beyond circadian rhythms, this multipurpose method in combination with powerful Drosophila genetic techniques offers the possibility to study diverse neuronal or molecular processes in live brain tissue.

Single-cell Resolution Fluorescence Live Imaging of Drosophila Circadian Clocks in Larval Brain Culture

The goal of this protocol is to establish ex vivo Drosophila larval brain culture optimized to monitor circadian molecular rhythms with long-term fluorescence time-lapse imaging. The application of this method to pharmacological assays is also discussed.

Encellede opløsning fluorescens Live Imaging af Drosophila døgnrytmen ure i larve hjernen kultur

The circadian pacemaker circuit orchestrates rhythmic behavioral and physiological outputs coordinated with environmental cues, such as day/night cycles. ...

Analyzing Neural Activity and Connectivity Using Intracranial EEG Data with SPM Software

Measuring neural activity and connectivity associated with cognitive functions at high spatial and temporal resolutions is an important goal in cognitive neuroscience. Intracranial electroencephalography (EEG) can directly record electrical neural activity and has the unique potential to accomplish this goal. Traditionally, averaging analysis has been applied to analyze intracranial EEG data; however, several new techniques are available for depicting neural activity and intra- and inter-regional connectivity. Here, we introduce two analytical protocols we recently applied to analyze intracranial EEG data using the Statistical Parametric Mapping (SPM) software: time-frequency SPM analysis for neural activity and dynamic causal modeling of induced responses for intra- and inter-regional connectivity. We report our analysis of intracranial EEG data during the observation of faces as representative results. The results revealed that the inferior occipital gyrus (IOG) showed gamma-band activity at very early stages (110 ms) in response to faces, and both the IOG and amygdala showed rapid intra- and inter-regional connectivity using various types of oscillations. These analytical protocols have the potential to identify the neural mechanisms underlying cognitive functions with high spatial and temporal profiles.

We present two analytical protocols that can be used to analyze intracranial electroencephalography data using the Statistical Parametric Mapping (SPM) software: time-frequency statistical parametric mapping analysis for neural activity, and dynamic causal modeling of induced responses for intra- and inter-regional connectivity.

Analysere neurale aktivitet og forbindelse med intrakraniel EEG Data med SPM Software

Measuring neural activity and connectivity associated with cognitive functions at high spatial and temporal resolutions is an important goal in cognitive ...

Wide-field Single-photon Optical Recording in Brain Slices Using Voltage-sensitive Dye

Wide-field single photon voltage-sensitive dye (VSD) imaging of brain slice preparations is a useful tool to assess the functional connectivity in neural circuits. Due to the fractional change in the light signal, it has been difficult to use this method as a quantitative assay. This article describes special optics and slice handling systems, which render this technique stable and reliable. The present article demonstrates the slice handling, staining, and recording of the VSD-stained hippocampal slices in detail. The system maintains physiological conditions for a long time, with good staining, and prevents mechanical movements of the slice during the recordings. Moreover, it enables staining of slices with a small amount of the dye. The optics achieve high numerical aperture at low magnification, which allows recording of the VSD signal at the maximum frame rate of 10 kHz, with 100 pixel x 100-pixel spatial resolution. Due to the high frame rate and spatial resolution, this technique allows application of the post-recording filters that provide sufficient signal-to-noise ratio to assess the changes in neural circuits.

We introduce a reproducible and stable optical recording method for brain slices using voltage-sensitive dye. The article describes voltage-sensitive dye staining and recording of optical signals using conventional hippocampal slice preparations.

Wide-felt enkelt-photon optisk optagelse i hjernen skiver ved hjælp af spændings følsom Dye

Wide-field single photon voltage-sensitive dye (VSD) imaging of brain slice preparations is a useful tool to assess the functional connectivity in neural ...