Electrophysiology

Electrophysiology

  • Tae-Yong Choi added an answer:
    7
    What do you think about hiPSCs, electrophysiology and LTP induction?

    Hi people,

    I have a "little" question for you. I would to know if it is possible to induce long term potentiation in hiPSCs and, if yes, what kind of protocol i could use?

    In literature i did not find any information about this.

    Thanks in advance for your answers.

    Tae-Yong Choi

    Hi. I think your idea is interesting but I think there are some problems. Some electrophysiologists don't like to study using cultured neurons because this condition is quite different from in the 'real' brain. For example, neural circuit is not perfect in this environment than in brain slice or in brain tissue.

    I think there are some possible experiments. How about chemical LTP? Many researchers using cultured neurons do this experiments and there are many references about it .

  • Somayeh Mojard added an answer:
    12
    How do you dinstinguish between dendrites and axons in neurons in culture?
    Eg by immunocytochemistry, is there a marker you can stain for? Or by e-phys?
    Somayeh Mojard

    Hello,

    Is there anybody to have experience with staining of rat primary sympathetic cells?

    I need some specific dye for axon through sympathetic nerves. I used TH, but it stains the dendrite also.

  • Ezequiel Marron Fernandez de Velasco added an answer:
    7
    How is going with my mEPSC shape and leak current?

    Dear Colleagues,

    I am learning to record CA1 neuron mEPSC in ACSF(1uM TTX and 100um Picrotoxin). During recording, I have some questions. Such as I recorded a lot of strange shape events and the leak current decreased constantly.

    Is these situation normal? How to improve my recording?

    The figures of recording are attached.

    Any comments and suggestions are all welcome. I really appreciate your help.

    Ezequiel Marron Fernandez de Velasco

    Hi Jason,

    another easy test you could do is adding 2mM kynurenic acid to the bath solution after the recording to check if all the events you see are AMPA mediated.

    Ezequiel

  • Zei Mom added an answer:
    13
    Hippocampal field EPSP recordings?
    I'm trying to record field EPSP from CA3 hippocampal subregion but it seems very tricky compared to CA1 as well as dentate gyrus. I'm using coronal brain slices and I tried sagittal slices as well but nothing seems to work. The problem is that all the response are barely detectable (around 0.4 mV) and they are also difficult to find. Do anyone have a suggestion for me? Change some solution or apply some tricks in order to have good responses such as change the stimulating elecrode (I'm using a bipolar concentric one)? Thanks so much. G
    Zei Mom

    Hello Everyone,

    First I do apologize for posting my question here. I just signed up and am quite new. I just started recording fEPSP from hippocampal CA1 region and the problem is that the signal amplitude I get is very small (between 0.2-0.5 mV). I do sagittal sectioning (300 µm) in cold ASCF and incubate for 1-1:30 h at 30 degrees. I work with 2-4 month-old mice. When I put the slices under the microscope, all the layers can be easily distinguished. The fiber valley is very very small which I think can be good sign.

    I have been struggling with this problem for a couple of weeks and tried many things to get bigger signal but nothing seems to work. The last thing that recently came to my mind was that maybe there is something wrong with the stimulation protocol. This is my first recording experience and I have no idea about how to make a protocol. The one that I am currently using is the one used by one of the students in other lab for recording EPSP from cortex and is apparently working perfectly for him. 

    Can anyone explain what each of the following is:

    First level, delta level, first duration, delta duration, digital bit pattern (#3-0) & (#7-4), train rate...

    Maybe I will be able to make a protocol for hippocampal fEPSP if I have a better idea about each of the above term and the best possible range they can be within.

    Also, does anyone have any recommendations for the positioning of the stimulating and recording electrodes? Is there any particular area to get the best possible response?

    I do appreciate anyone's help in this regard. There is no one around me with hippocampal fEPSP experience and I am extremely frustrated and disappointed for not being able to make it work.

    Thank you all in advance

  • Ezequiel Marron Fernandez de Velasco added an answer:
    3
    Whats the difference between a postnatal day4 and day 5 in mice (elecrophysiology recordings)?

    I will need to do organotypic slices for electrophysiology recordings

    Ezequiel Marron Fernandez de Velasco

    Hi Anna,

    I have been working with hippocampal organotypic cultures for some time and, as Refik also mentioned, a 1 day difference in age did not have measurable effects in my recordings. A bigger difference both in the age of the pups or the amount of days of the slice "in vitro" did have a noticeable effect. I think that as long as you stay within the 1-2 days range it should be fine but of course it also depends on your particular study.

    Hope this helps,

    Ezequiel

  • Turgay Temel added an answer:
    4
    Is there a procedure to represent a multi-channel EEG in terms of neuro-spike time intervals?

    Is there a procedure to represent a multi-channel EEG in terms of neuro-spike time intervals? Any resemblance for encoding neuro spikes of brain waveforms measured via EEG?

    Thanks

    Turgay

    Turgay Temel

    Dear Francois,

    Sorry for answering or clarifying late. Yes, you are right. I wonder if there is any method to represent multi-channel EEG waveforms in terms of neuro-spike time intervals. Although it is much simpler in frequency domain when it comes to multi-channel temporal behavior is not well formulated as far as I know, for which I might be wrong too.

    Best

    Turgay

  • Robert Moss asked a question:
    Open
    In relation to neuroscience and interpersonal relationship patterns, or personality, what is the current status and where are we headed?

    AIMS Neuroscience is requesting paper submissions for our September issue. Manuscripts will need to be received by 30 July 2016, and decisions on acceptance will be completed by 30 August. The aim of this special issue is to establish the relation to neuroscience and interpersonal relationship patterns. Examples of research have involved the Big Five, brain structure, and neurotransmitter variations, as well as oxytocin and trust. Is our understanding of the brain at a point that it is possible to explain relationship behavior patterns and how to differentially deal with individuals based on that understanding? Please add your own answers here as well to stimulate discussion and interest.

  • Guillermo solis fernandez added an answer:
    3
    How can I calculate voltage for half-maximal activation of an ion channel, from the membrane potentials and amplitude current values?

    I want to calculate voltage for half-maximal activation and the slope factor from a series of membrane potential (voltage) and amplitudes currents for a given ionic channel.

    Guillermo solis fernandez

     Thanks Norbert, I am working with voltage gated-channels so I will try to apply the procedure that you explain. 

    Also thanks to Marcus for the protocol on measuring on whole cell and the software packages to do the fitting

  • Tianyang Ma added an answer:
    8
    How do I make the headstage and omnetics connect tight and how frequently should I turn down the tetrodes in chronic recording?

    I am doing tetrode recording in freely-moving rats with intan RHD 2000 amplifier. These days the amplifier and omnetics are frequently disconnected. I tried with the crocodile clamp and tape, but neither helped. And for the recording, we have a commutator which could guarantee there wasn't too much tension on the cable.

    The rat scratched a lot and sometimes even shaked the head fast, which made the connection even looser. Is there anyone who has the same experience and has some suggestions?

    Also, once I turned down the tetrodes after 5 days' recording, then I found I couldn't change the position of tetrodes, although at beginning I could. Is that because the dura grows back? Usually for chronic tetrode recording, how frequently should I adjust the position of tetrodes. Thanks!

    Tianyang Ma

    Hello Jonny,

    We don't use hex and phillips screws. We use the one suggested by open ephy. The shape is half top and half bottom. And one turn is around 260 um. I do prefer to look for other kinds of screws if possible.

    Best,

    Tianyang

  • Simon D Klapper added an answer:
    18
    What is the best way to detect spontaneous miniature currents using Clampfit9?
    I recorded spontaneous miniature currents from neurons in the brainstem at different time points (postnatal day 3 to day 18 in mice). The detection of these small currents (amplitudes ranging between 10pA and 100pA, most of them are between 10pA to 30pA in size) have been a nightmare. What I have been doing currently is to create a template using the trace I record at each age with about 10 typical currents then detect the number of current wavelets using the template with varying detection threshold (1 to 4). The trouble is, for different age groups, the signal to noise ratio is different e.g. at younger ages, the current amplitudes are small so the signal to noise ratio is low, and vice versa. So I have been using higher detection threshold (4) for young animals and low detection threshold (1 or 2) for older animals. However, sometimes there are still noise picked up and not all current wavelets can be detected. My noise level is around 10pA with 5kHz low pass filter, but I filter offline at 1kHz low pass and the noise level is around 5pA.
    Does anyone know a better way to detect these spontaneous miniature currents (ideally with softwares I have or free softwares I can easily obtain)? I have Clampfit9 and Origin Pro 8.2. The number of spontaneous currents in each trace is over 1000 so doing it manually would be impossible.
    Simon D Klapper

    Sorry for hijacking this old question, but I have an current issue that fits well to this discussion:

    It is interesting, that after all this time, MiniAnalysis by Synaptosoft is still popular, although, according to my experience, support has ceased long time ago. I also used this software until recently, but now I guess I have to switch, because the new ABF2.x files are not at all supported any more, and Molecular Devices is not offering a batch conversion tool to "downgrade" the files (reply from their support). A question to the Synaptosoft technical support concerning this did not produce any answer yet. And I have my doubts that there will be neither an answer nor an update, because there where no updates since a long time and content is not updated either. I also would hesitate spending money onto this company, because I am not sure whether it is actually still running?

    So I am considering doing the analysis in Clampfit, too, using the hints provided here, thanks. Although I know that high troughput and (semi) automated analysis is bit cumbersome there (even the guys from Molecular Devices admitted during a conference, that they can't beat Synaptosofts software).

    But my question is, why is there no competitive, fresh new software like MiniAnalysis? Is everyone using mostly ClampFit or are people using custom scripts (MatLab, for example)?

  • Peter Bayguinov added an answer:
    1
    Has anyone used the Thorlabs Two-Camera Mount for Microscopes? or used an alternative?

    The experimental set up requires two cameras to be fitted to an olympus scope, one for fluroescence imaging, one for IR-DIC. We have the two cameras in mind, but need to fit them both to the same scope. This looks like a useful approach from Thorlabs: http://www.thorlabs.de/newgrouppage9.cfm?objectgroup_id=9143

    Just wondering whether anyone has tried it? Tried something similar? could recommend anything else?

    Peter Bayguinov

    We use something a bit simpler, and likely way cheaper, from QIOptiq that allows us to use our IR-DIC camera along with an EMCCD camera. The advantage is that there aren't any optics that may reduce the emission (like there seems to be on the Thor mount). Here's a link. http://www.qioptiq.com/optem-multi-port-series.html

  • Stefan Weigel added an answer:
    6
    Is it possible to measure the membrane potential of live cells in a 96 well plate using voltage sensitive dyes such as oxonols?

    A protocol and any pointers to papers which show a protocol would be great.

    I want to alter the culture medium and measure the membrane potential as a result of this change in the culture medium. That is why I am looking for a protocol to measure the membrane potential of live cells in a 96 well plate. 

    Stefan Weigel

    Dear Shakil,

    we are also using so called hybrid voltage sensor imaging using DiO/DPA pairs as mentioned by Kristina. This gives you very good S/R and high fluorescence changes due to APs (in the range of 10-20%).

    You only need to label your cells with a yellow or cyan fluorescent dye (e.g. DiO) and apply DPA to the bath solution.

    We are applying this to brain slices. The toxicity is lower compared to RH795 or Di-8-ANNEPS.

    Best regards,

    Stefan

  • Safal Khanal asked a question:
    Open
    Are there any guidelines/codes on how to run slow flash and global flash mfERG paradigm on Reti-Scan?

    Especially concerned with the insertion of three dark frames for slow flash and two dark frames and a global flash for global flash mfERG in between the hexagonal binary on and off sequences...

  • Tim Blanche added an answer:
    4
    Any advice for a good stimulus isolator for electrolytic lesions?

    I want to buy a new stimulus isolator that generates current in the 10 uA range for electrolytic lesions following tetrode recordings. Does anyone know of one that they think works well and reliably? We've used the World Precision Instruments A360 in the past (now outdated). 

    Tim Blanche

    My company makes the nanoZ, a fully automated 64 channel impedance tester and electroplating device that can be used to make electrolytic lesions with tetrodes. It can deliver up to +/- 12uA (voltage compliance +/-5V). Please check out our website (www.white-matter.com) or contact us at info@white-matter.com if you are interested in a quote.

    Any advice for a good stimulus isolator for electrolytic lesions? - ResearchGate. Available from: https://www.researchgate.net/post/Any_advice_for_a_good_stimulus_isolator_for_electrolytic_lesions [accessed Jan 5, 2016].

  • Norfarah diana Aba asked a question:
    Open
    For a negatively charged membrane for RO application, how is overall salt rejection heavily dependent on anion rejections?

    Donnan potential is benefit in -vely charged membrane, where they can reject negatively charge ions (for example Cl-), and what happened to Na+ ions? Did it pass through?

    How about +vely charge membrane, and did Donnan potential is valid if the aim is to reject +ve ion, eg; Na+?

    I have serious confusion on this. Your help is much needed and appreciated. 

    many thanks!

  • Euan Robert Brown added an answer:
    3
    Can anybody tell me how to measure the extracellular concentration of sodium and potassium ion of nerve cells ?

    Can anybody tell how to measure the extracellular concentration of sodium and potassium ion of nerve cells ?

    Euan Robert Brown

    Hi,  question is  how  fast and how accurately you want to do this and what equipment you have to hand ?  There are now K+ dyes available  for extracellular recording but they are not very accurate if your extracellular space is less than the Abbe limit and can't be resolved (less than 250 nm). There are of course a few 'traditional methods to do this. Depending on what you have availably in terms of equipment:

    1. Extracellular ion sensitive micro electrodes. Pros good point accuracy measurement.  cons poor time resolution (response time slow)  and they tend to 'make' a several micron space so don't really reflect the real K concentration. Also there are iononophores availably for Na as well.

    2.  If your cell has well characterised K currents and you have good whole cell voltage clamp,  you can use the change in reversal potential of the K current to measure the resting and dynamic changes in extracellular K concentration.  this is very accurate and has good time resolution but requires a bit of nifty calculation.  If they have prominent Na currents you could use them as well to determine the extracellular Na concentration. 

    Hope that helps (I can send you refs for the 2nd option if you are interested.

    good luck!

    Euan

  • Xiao-hui Zhang added an answer:
    2
    Difference between phosphate and bicarbonate buffer in neuronal recording?

    The buffering range of PBS and BBS seems to be quite similar to me. However, from literature it seems that many of the neuronal recording (both electrophysiology and FRET) are done with BBS. Is there a specific reason for this?

    Many thanks in advance,

    Anu

    Xiao-hui Zhang

    Yes, it is correct.

    Xiaohui

  • Tharaka Darshana Wijerathne added an answer:
    13
    How do I Calculate/Plot a Conductance-Voltage Curve from Current-Voltage Data?

    Hi all

    I have Current Voltage data obtained from voltage clamp recordings. The data is from HEK293 cells over expressing BK(Slo1) channels.

    I used a step protocol (holding at -100mV  | +24mV steps (300ms Long) | from -124mV to +260mV [Total of 17 Steps])

    I plotted the Current at Each step against the step voltage to get the IV Curve (Attachment 1). The data pints I used to plot the IV Curve are in attachment 2

    Now, I want to get the GV Curve (Conductance-Voltage Curve). How can I do this?

    I followed the following method and I faced a problem which I cannot solve

    To get the GV Curve, I divided the current at each step voltage  by the diffidence between the step voltage & reversal potential (V-Vrev)

    e.g at +116mV the Conductance=1127.92pA/[116-(-56)]mV

    Reversal potential obtained by current clamp mode is -56mV (LJP corrected). Without the Liquid junction potential (LJP) correction, the reversal potential is around -43mV. 

    Then I plotted the new data points. (Attachment 3)

    The problem I have is the sudden spike at -52mV (Circled in Red in the plot). I understand this comes because I divide the current at-52mV by a very small value (-52-[-56]) compared to the values around that point [e.g at -76mV the V-Vrev is -76-(-56)=-20 which is a firly big value which results the I/(-20) a very small value]. 

    Have I done anything wrong? This is my first time working on Voltage gated channels. 

    Please advice me.

    Thank you all

    + 2 more attachments

    Tharaka Darshana Wijerathne

    Dear Warren. 

    Thank you so much for the clear explanation.

    I calculated the GV curve as you said from one of my reading from Slo3 (Voltage gated Potassium) ion channel (Image 1.1).  The point I used to obtain tail current is zoomed in the image 2 (Red arrow). I assume the blue arrow as capacitative current.

    So I plotted the normalized tail current at blue arrow together with the calculated slope from normal IV Curve (image 3).  The two plots seems different. Can you please suggest any reasons. 

    My step protocol is -100mV hold, +24mVx14 steps (300ms long). So the final step is +212mV. Gap between two steps is 4 seconds.

    Solutions used are internal- 130KAsp 7.3pH and external 140Na+5K (I assume having asymmetrical Potassium concentrations is not going to be a problem. )

    IV Curve calculated from STEP is at 4th image attached 

    Thank you again

    + 3 more attachments

  • Don Mann added an answer:
    3
    Is anyone doing research on the extraction of biological signals using atomic magnetometers positioned remotely (>10cm) from the body?

    Recent research has enabled EEG readings with a sensor 4mm away from the skin:

    https://www.osapublishing.org/boe/abstract.cfm?uri=boe-3-5-981

    In 2013, an extremely sensitive atomic magnetometer was designed that does not require stringent shielding from the Earth's own field:

    http://physicsworld.com/cws/article/news/2013/apr/24/atomic-magnetometer-is-most-sensitive-yet

    I have discovered super sensitive sensors that can be flown in airplanes and can detect submarines, their screws turning and inside machinery:

    https://www.youtube.com/watch?v=BTThA_PmF1k

    One would think that this would support the possibility of extracting EEG using this technology. 

    If one could remotely extract biological signals using non-invasive technologies that allow for a full range of mobility and free-ranging activities in an un-shielded open environment, then there are a tremendous number of opportunities that would become available in the rescue, policing, medical, commercial, and military arenas, such as; neuroprosthetics, exoskeletons, sleep/hibernation systems, pain reduction systems, threat detection systems, interrogation devices, dictation devices, secure/silent speech, games/simulations, advanced security devices, monitoring EKG/EEG readings of those in critical care units, increasing mobility of those suffering from limiting or confining ailments or seizures, etc.

    Don Mann

    What impedes the operation of a capacitance electrode beyond 4mm?  I suggest 4mm as the extraction of EEG readings at a distance of 4mm has already been done.

  • Barbara Niemeyer added an answer:
    1
    Could anybody give us any basic tips how to determine TEER with an Ussing Chamber?

    We just started to use a ussing chamber system with cell culture transwells in our laboratory (U9500 Warner Instruments) and do not really have any experience in that field so far. Is there anybody who could give us basic advise what is crucial for such experiments? Assembly of Chamber, Electrodes+Agar bridges etc is not the problem, but unfortunately we do not know if our results are plausible or not.

    I attached a picture of what we recorded in one of our last experiments. The lowest two Graphs are the calculated membrane resistance. Unfortunately we do not have any idea why the voltage traces look so different. It would be great if we could get some advice what could be our problem.

    Barbara Niemeyer

    Hi,

     I would suggest to contact Dr. Jens Leipziger at Aarhus University in Denmark, who has profound experience using hte Ussing chamber.

  • Saak V. Ovsepian added an answer:
    1
    How do I place the stimulating electrode in mouse contralateral dorsal hippocampus to activate commissural CA3 synapses on the ipsilateral CA1?

    Dear fellow researchers,

    In the mouse, to study in vivo Schaffer collateral - CA1 pathway LTP, I want to stimulate the Schaffer collateral pathway from the contralateral side and record field potential responses from the ipsilateral dorsal CA1 stratum radiatum (stereotaxic location: AP: -1.46, ML: 1.0). I considered two contralateral stimulating locations:

    1) the location homotopic to my recording location in CA1 (AP: -1.46, ML: -1.0, DV - at stratum radiatum) and

    2) the pyramidal cell layer of CA3 (AP: -1.46, ML: -1.5, DV - at CA3 pyramidal layer).

    Your input in choosing one of the two above is really appreciated because I think both options seem to have some issues.

    Option -1 (stim electrode in CA1 s. radiatum) - this likely activates two pathways - a) the Schaffer collateral path ipsilateral to the stimulating side, which then antidromically activates contralateral CA1 and also antidromically activates CA3 on the stimulating side which may then activate contralateral CA1. b) the CA1-CA1 associational pathway - this could happen because the electrode might stimulate the CA1 pyramidal cells too. My question is which of the two pathways (a & b) contribute more to the evoked responses? 

    Option-2 (stim electrode in CA3 pyramidal layer) - stimulating from this location will orthodromically activate CA1 cells on both hemispheres. Hence, this for sure will activate the Schaffer collateral I am interested in but will also activate CA1-CA1 associational pathway. Do you think the Schaffer collaterals will contribute more to the evoked responses in this case compared to option-1?

    Which option is better in general considering other things I haven't mentioned here?  

    Note that I do not want to place stimulating and recording electrode on the same hemisphere for technical reasons.

    Thanks

    Mani

    Saak V. Ovsepian

    Dear Mani:

    You managed to put a quite straightforward question in a complicated way - ) What you would like to do, as I understood, is to measure the LTP of commissural inputs to CA1 neurons of the dorsal hippocampus. And you want to know where to place your stimulation electrode.

    There are numerous papers on this topic and best will be for you to check them and read some of them as there are details that you need to be aware. As a starting point I would suggest to check the paper by Bliss, Lancaster and Wheal in JP (see below). I hope this will give you some background and will serve as a good starting point. 

     http://www.ncbi.nlm.nih.gov/pubmed/6620191. Hope this will set you on the right path. 

    Good luck,

    SV  

  • Refik Kanjhan added an answer:
    5
    Should I perform ACSF with MgSO4 or with MgCl2?

    Several authors working on spinal cord acute whole-mount prep (or acute slice prep) add c.a. 1.5 mM MgSO4 to their Standard ACSF . The use of 1.0-1.5 mM MgCl2 is instead mostly widespread amongst authors working on other parts of the CNS (and what I tipically used so far in cortex, hippocampus cerebellum, brainstem...).

    Given that in all other ingredients recipes are equal, is there a particular reason to add MgSO4 to spinal cord-ACSF rather than MgCl2... or is this just (as I guess) a sort of "founder effect" applied to ACSF recipes?

    Apart for Magnesium (see above), with Standard ACSF I mean c.a. 125 NaCl, 2.5 KCl, 2 CaCl2, 1.2 Na2HPO4, 10 Glucose 26 NaHCO3, c.a. 300 mOsm, pH7.4 with CO2/O2 (small variations  according to each author).

    Thanks in advance for your Kind suggestions and contributions!

    Refik Kanjhan

    I regularly cut spinal and brainstem sections with vibratome for electrophysiology. I have tried both and have not noticed any significant difference. I guess 2 mM difference in Cl- concentration will not make a significant difference. I personally prefer MgCl2.

    cheers, Refik

  • Gila Behzadi added an answer:
    5
    How to identify cortical layer boundaries in live brain slice?

    I am struggling to find cortical layer boundaries in mouse brain slice under differential interference contrast microscope. I typically use 400 um thick brain slice for my electrophysiology recording. Under 40x lens I kind of can see that the upper layers have smaller soma size and the soma is dense and in layer 5 the soma is bigger and sparse compared to upper layers.

    The best image I can find online is this one in somatosensory cortex (http://jn.physiology.org/content/92/4/2185), in which mouse barrels in layer 4 can be easily identified.

    Could anyone give me some links of good examples for identifying cortical boundaries in live brain slice?

    Thank you in advance!

    Gila Behzadi

    According to Paxinos & Watson atlas:

    Barrel cortex: 2.3 mm posterior to Bregma,Lat 4 mm, V 1.5-1.8 from cortical surface (layer 4)

    Motor cortex: 1.7-2 mm rostral to Bregma, Lat 1.5-1.8 mm, V 1.7 from cortical surface (layer 5)

  • Jonny Saunders added an answer:
    8
    Patch primary human coronary artery smooth muscle cell (HCASMC) - whole cell configuration (electrophysiology)

    Hello all,

    I am trying to patch primary HCASMC, it was working fine but all of the sudden everything upside down. I am wondering if anyone have any tricks / experience on patching HCASMC.

    Here is the details of condition: The cell was grown in recommended medium (contains 5% FBS) I usually plate the cell on coverslip 12h ahead of patching. The glass coverslip was treated with 100 uM NaOH and wash thoroughly then autoclave. I do not have a problem on getting giga ohm seal. I am using pipette around 2.5 to 4 mOhm.

    But recently I'm having trouble getting into the whole cell configuration, >50% of the time as soon as it breaks in it's lost the cell. Even when I got the whole cell configuration, I lost it within 10 min or as soon as I start to prefuse my compound, it lost the cell.  There was one weird case is the cell get to whole cell configuration automatically after it stays on giga ohm seal for couple mins.

    Besides, when I looked at the microscope, at the beginning, the pipette touch the middle of the cell then, as the time goes, the pipette moves/ the cell moves to the edge of the cell. My colleagues checked and told me she did not see the pipette moves for 30 min in bath solution so I guess the pipette holder is fine.

    Any advice and suggestion are appreciated and Thank you very much in advance for any suggestions

    Jonny Saunders

    How is your perfusion set up? If the flow is too high it could cause instability as well - this is especially important since you are doing a dose-response, rate of flow can affect things like binding constants.

  • Stephen Wilson added an answer:
    6
    Electrophysiology Recording in the Retrosplenial Cortex (RSC); is it normal to have short cell survival time compared with other brain regions?

    I have been trying to patch in the RSC of slices taken from two month old mice. i have been noticing that the cells don't survive for very long after the preparation compared with other brain regions such as the barrel cortex. Has anyone else experienced something similar? Do you have any recommendations on preserving the neurons in this area for longer?

    Stephen Wilson

    Hi Benjamin,

    We were removing the skull by cutting around the left and right hand side of the base of the skull from the back before peeling it up and removing the brain with a small spatula. We did this to try and avoid cutting near the RSC.

    Tohru,

    Thank you for your responses! They would certainly have been useful but I have now finished the data collection part of my project so I can't go back and change anything now. 

    Thanks both for your help,

    Stevie

  • Jeffrey G Edwards added an answer:
    4
    Do whole cell and field potential electrophysiology typically produce different findings?

    I have produced results contrary to previously published literature in a similar experiment. There are technical differences between these studies, one of which is field potential recordings versus whole cell recordings. Does anyone know if this technical difference is enough to explain the differences in results?

    Jeffrey G Edwards

    If slice health is not good that could also cause you not to see plasticity (LTD) in your preparation. Otherwise, in whole cell a washout effect can occur, but is less likely if they are still seeing an effect.

  • Andrea Moreno added an answer:
    3
    Has anyone separated (cut) the hippocampus in vivo whilst recording LFPs?

    Does anyone have experience in cutting the hippocampus (to separate dorsal from ventral hippocampus) in vivo (anesthetized rat) whilst stimulating and/or recording electrophysiology? If so, would you recommend me which coordinates and methods are less damaging? (scalpel, blade...?)

    Thank you so much in advance!

    Andrea

    Andrea Moreno

    Thank you for the answers! and sorry for the delay in replying.

    Konstantin, I contacted Victoria Talko as you suggested, but unfortunately they currently don't have those experiments running. But thank you very much for the contact!

    Robert, Certainly you're right! I had found this paper from the Mosers lab in 2002 (http://www.ncbi.nlm.nih.gov/pubmed/11867718) and this is the one I'm trying to replicate, but Im not sure if anyone has repeated this procedure afterwards using electrophysiology recordings (I guess the trickiest thing for me is to keep the ephys baseline stable when you cut through the cortex). 

    Andrea.

  • Benjamin Allitt added an answer:
    6
    Is there any model that tries to explain the short-term synaptic plasticity using only the spike trains?

    Lots of works is done using the intracellular recordings, but I'm more interested in doing the same using only the spike trains.

    Benjamin Allitt

    So everyone is linking you to papers. Do vector strength and entrainment analyses. You'll find your answer there. Short term calcium binding may give you a physiological explanation outside of electrophysiological responses. 

  • Toshio Murase added an answer:
    1
    Does anyone know how I can get precise data about ion pumps in cell membrane?

    I am searching for data about ion pumps in cell membrane to improve my model on my e-cell. My problem is lacking data of numbers of ion pumps(for instance, how many Na+ pumps in one cell) and their coefficient of ion diffusion. Would you please provide me some resources about these data,or just telling me the reference or database to search on?

    Toshio Murase

    I have no idea.

About Electrophysiology

The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organsims.

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