Neurophysiology - Science topic

Hello dear professor.

I am currently a PhD student in physiology in Iran and I am accepting my thesis papers. I am interested in studying in the post-doctoral course. If you are familiar with the conditions of my country, we are facing severe sanctions and hard research work. I also barely finished the thesis. I need to get financial aid to be able to enter this course. And how good that your Ph.D. course is 3 years, Iran we finish this course in 4 years, but under the strict conditions of 5 years of experience. Your number one project is exciting.

Thank you very much

When using a Gaussian kernel to smooth neuronal firing rates, the choice of σ (sigma) determines the spatial extent of the smoothing. A larger value of σ results in a wider Gaussian kernel and a smoother firing rate estimate, while a smaller value of σ results in a narrower Gaussian kernel and a more localized estimate.

The choice of σ depends on several factors, including the desired level of smoothing, the noise level in the data, and the spatial scale of the phenomena being studied. In general, there is no one "correct" value of σ that works best for all cases, and it is often necessary to choose a value that balances the need for smoothing with the desire to preserve important features in the data.

One approach to choosing σ is to perform a sensitivity analysis in which different values of σ are tested and the results are compared. For example, one could plot the smoothed firing rate estimates for a range of σ values and visually inspect the results to determine the level of smoothing that best preserves the relevant features of the data.

Another approach is to use cross-validation, in which the data is divided into training and testing sets and different σ values are tested on the training set to determine the value that produces the best predictive performance on the testing set.

Ultimately, the choice of σ will depend on the specific data being analyzed and the goals of the analysis. It is important to consider the potential trade-offs between smoothing and preserving important features in the data, and to choose a value of σ that produces a balance between these factors.

Zeeshan Mushtaq Thanks for your answer. I also think that is the adapter. Maybe A-M sytems have the original cable, but I doubt it. I will try it anyway. Thanks a lot

Depends on your situation and time availabilities, but summer schools are great opportunities for hands-on training and they typically cover accommodation and food (although that does mean they are very competitive). There are many of these, just search for summer schools in neuroscience online, but the first that come to mind for 2023 are the Transylvanian Experimental Neuroscience Summer School (https://tenss.ro/) and the Amgen Scholars Program (https://amgenscholars.com/).

There are also many courses offered, but these often charge fees, although may also offer financial support, e.g. courses at the MBL (https://www.mbl.edu/neuroscience).

Hope that helps!

Dear Jelena, I'm interested in evaluating the activity of different natural compounds on EEG changes in mouse brain. However, I do not have a person equipped with instruments to perform EEG on mice.

Thank you, Nicolas, I think Pulsepal will help my experiments.

Thank you so much Mr Fouad Lemtiri-Chlieh. Thank you for your attension and information.

Hi Claire,

In what aspects did your surgery technique improved?

Here are some articles you might find useful...

Hi,

You can go to pubmed and type your keywords and get the desired articles.

There are journals like and many more

J.of Neurophysiology

Cognitive neurosciences

We use a micro drill from cell point scientific:

May I ask if you continue your experiment and find a good agent? I am also thinking about fixing my cells on a coverglass right after treating with Fura-2 AM and I am wondering if fixation processes by 4% PFA may effect the membrane permeability and cause Ca2+ fluorescence to be lost.

Here's an application, from a covid paper to be published in journal of biological rhythms. I'll attach a circannual figure on the immune system, taken from birds.

I would call it a quasi experiment with intervention. Diabetes compared with non diabetes.

outcome in each group measured by difference post-pre intervention, then difference in outcomes between groups assessed

also could be called a non randomised clinical trial.

We do a lot of single-cell electroporation and routinely include one of the non-Dextran Alexa dyes - 488 or 564 usually. Never seemed to have any problem with the fluorophore. Probably the Dextran dye also won't cause any problems but I never tried it...

Hi there, does anyone have issues with getting the right resistance before even getting experiments started? We've had a few batched where the resistances were all in the giga ohm range but was apparently due to issues at production and now having the same issues with a new batch! Any help or advice would be greatly appreciated!!

Kindly read this article this might help in answering your questions.

Nice Contribution Michael A. Hunter

I Agree With Wei-Peng Teo

Dear Dr. Ebada,

We know very little about COVID-19 at this moment and its effects on the developing and/or mature brain. In general viral infections can impair charnolophagy (CB autophagy) which is the basic molecular mechanism of intra-cellular detoxification (ICD) for normal function to remain healthy. By attacking the most sensitive neural progenitor cells in the brain, the virus can alter their pluripotency and induce charnolosome (CS) destabilization implicated in inflammasome (particularly NRLP-3) activation to induce hypercytokinemia and charnoptosis (CB apoptosis) implicated in pyroptosis, apoptosis, and necrosis of sensitive hippocampal and other CNS neurons by releasing Panx-1, Viroporine, and gasdermins to cause Charnoly Body Molecular Pathogenesis (CBMP) implicated in early morbidity and mortality through its general (Viral) lytic cycle.

For more details, you may please refer to my books " The Zika Virus Disease: Prevention and Cure" The Charnoly Body: A Novel Biomarker of Mitochondrial Bioenergetics" Fetal Alcohol Spectrum Disorder; and Nicotinism and Emerging Role of E-Cigarettes. I wish I could write more about it.

Dr. Ebada, It is all about Environmental Sanitation, our own Life-Style, Immunity, Mitochondrial Bio-energetics and intracellular detoxification through charnolophagy (CB autophagy), which is compromised by COVID-19 through CS destabilization to cause early morbidity and mortality by infecting the CNS. Thanks.

With Warm regards,

Sushil Sharma, Ph.D; D.M.R.I.T

Academic Dean

American International School of Medicine

Guyana, South America

.

Please see the links below.

Pain management education course

Andrew Chao no the project we were working on this for is currently stalled but will likely pick back up come May/June so if you figure this out it would be greatly appreciated. Likewise if we figure it out I'll send what ever we end up doing over your way.

@Enrico We assume the physical framework built up by the baseline of upper teeth is the physical correlation to grid, HD, cells. Krupic et al. 2015 showed the grid cell symmetry shaped by environmental symmetry ("Grid cell symmetry is shaped by environmental geometry"). This supports a direct connection to the environment, the body and the brain. Various pathways supporting the connection between the baseline of upper teeth/ C0-C2 and grid cells have been found in principle qualification (see quotes in the article), however they have not been applied for this yet unknown aspect so far.

For those still following - I have revisited this problem and solved it by using the NVIDIA compiler instead of visual studio.

But the Neuropil is not a chorus, as we once thought it might be. Standing back it seems more like a cacophony of noise rather than information. Myelination is at least somewhat like insulation, but what gain to get the message clearly from one station to another in some logical form when at the latter a kind reply: "thank you, but what to do? What to do indeed.... .Looking at a dendritic tree, for example, what are its contributions to moving forward the message of the contacting neurons past the hillock and synapsing on the contacted neuron, before the hillock? Can we grab inputs from a couple neurons and subsequent outputs onto other neurons and assume veridic messaging transmission? What of the spreading depolarizations connecting through synapses to cell A, cell B, cell C.....etc, what does a signal distorted and spread over three neurons (A.B,C) mean to someone with a complex cognitive bend? What is information, what is destabilization, either in a muffling of or the screeching of a message? One makes it too poor to be informative, the other too rich to be so. So far, most modeling uses statistics to elucidate propensity, but survival goes to the swift and sure footed and such a model is neither. Does experience delegate attributes to the final common path so that we can effectively define motor circuits by the action of the effector organ? And what of all the ionic flux in areas where it perturbs the outcome. Is there a system on the line that proclaims: no, no,no,no, your flux is disruptive so you shall not pass? Which are the synapses that instruct and which the ones that shape the response? Can anyone find a code in a brain stem neuron that's reflected in a spinal motoneuron and a muscle cause change at a joint? Is it easier to repeat that movement? Why? Do we still believe that it's all in an instructional code? If so, that would be most baffling. We used to speak of all-or-none axons, but what about the stuff at the front and at the back ends of a neuron, where conduction is compounded? Is it all a common code translated into the language of the local setting? Who are these brilliant translators in wetware that can be amazing as those in hardware?Blood flow is so regular as to make graded endocrine messaging somewhat reliable. But neuronal transmission rarely occurs in media that are reliable transmitters time after time as are seen in the effect at the neuromuscular junctions.....and we haven't even talked about the many things we think inhibitory neurons do!

But in the final analysis we know rich cognitive experiences. So all this has some coin of the realm that leads to a message e can clearly hear as that "voice from within." By contrast neuroendocrine neurons seem like child's play in their reliability. What makes them so, as neuroendocrine activity needs strict parameters to function?

Madam you can sent your atrtical at Euro J Applied. Physiology, American J physiology, J Exercise&metabolism, many more. Thank you with kind regards

I am a Biomedical scientist and a Biochemist

Oh, the phase-locking between spikes and theta LFP change with the moving speed. I get it, thank you!

Mehr - I assume with qEEG, you mean spectral / time-frequency analyses? I think there is no general answer to your question, it highly depends on the specific neural process that you are interested in. qEEG is more flexible, in that it can be applied to resting-state data and a variety of experimental tasks, whereas ERP analyses depend on a precisely timed and thoroughly prepared experimental paradigm. qEEG is a bit more complex in terms of analyses, but with modern analysis software, it's still quite convenient to do. But as I said, your choice is highly dependent on what exactly you are interested in.

HTH, Marius

I completely agree @Stephen Politzer-Ahles. You should have an idea at least what kind of brain activity will be of interest. With respect to technical aspects: It doesn't make a big difference to investigate ERP or qEEG because the data acquisition is nearly the same - you need skalp electrodes, pre-amplification, filters, amplification and a data digitization and recording unit. For ERP you probably have to acquire something like a trigger trace in addition. Focussing on one of the methods means to perform different ways of post-processing of your data.

Can one use N2a cells s.c. injection to study tumor growth in other mice strain then AJ?!

Dear Matthijs, just a quick follow-up since you mention "air drying and mounting in moviol":

My approach is to keep the slices always submerged, as much as possible. During some washes / rinses I might remove almost all the solution, but this is just for an instant before the new solution is added, and the slice itself still retains a fine layer of solution on it during the swap. For mounting I have used DAKO mounting medium, and also Prolong Gold or Diamond. For sealing I use Biotium Covergrip.

When mounting: place a clean coverslip onto a work surface (I find it useful to elevate the coverslip slightly, for example by placing it onto an upside-down cap from a 50 ml Falcon tube). Use a transfer pipette to carefully place the slice upside-down on the coverslip. This ensures that the slice lies flat against the underside of the coverslip during imaging. The slice will be floating slightly in a drop of PBS (or similar). Use a Pasteur pipette to siphon off most of the solution without generating bubbles. Work rapidly to avoid drying out the slice. Use the edge of a fresh Kimwipe tissue to suck away remaining moisture at the edges of the slice (never touching the surface of the slice). It's okay if a bit of moisture remains, don't spend too long on this. Then add several drops of mounting medium onto the slice (how much is a matter of practice and preference - for DAKO I'd say 4-5 drops). Put spacers at the left and right edges of the coverslip: for a 300 um tissue section, I use 4 small square coverslips of #1 thickness (each 150 um thick, two on each side). Place the glass slide down onto this assembly - to avoid air bubbles, it may help to "roll" the slide down from e.g. the lower edge to the top edge (the idea is that air bubbles will be forced towards the edge this way). Cover from light and let it cure in this position (1 hour might suffice), then flip it right-side-up and store it at room temperature overnight to allow adequate curing. For Prolong Diamond, it may take up to 1 week to fully cure. Then seal the edges with Biotium CoverGrip. Once the Biotium is dry, you may optionally re-seal with nail polish. Nail polish alone should be avoided as it can bleach GFP (and perhaps other fluorophores?). Store at 4C in the dark, in a slide box that keeps the slides horizontal.

Some of these details are in the Methods of my papers:

That said, plenty of people use Mowiol, so I doubt that is an issue.

You might search for "spatiotemporal receptive field" (or "STRF") on Pubmed or Google. There have been a variety of attempts to characterize visual receptive fields in terms of both space and time. These attempts are closely related to the study of STRFs in the auditory system. (In the auditory context, STRF stands for "spectrotemporal response field".)

I'm not a visual neuroscientist and so I won't attempt to offer a good review paper (perhaps somebody more knowledgeable than I can). But definitely temporal properties of visually-responsive neurons have been a major subject of study for many years.

It turns out that the statistical analysis of any binary decision (choice between two options) can be reduced to a model based on a single decision variable (a scalar variable) crossing a threshold. This is true no matter how the decision making is actually carried out. As I recall (I might be mistaken), a proof of this is given by Jaynes in his text "Probability Theory: The Logic of Science".

The strength of the signal detection theory in psychology is that it can be applied no matter what is taking place in the brain. The theory gives a good way of studying decision performance, as viewed by the external objective observer.

It is wrong to think that the signal detection theory requires or implies that there necessarily or actually exists a single biophysical or neural level of some kind in the brain of a subject, that crosses a threshold of some kind, causing them to make a decision about signal detection. The theory applies even for very complex processes, possibly involving countless unknown levels and thresholds for instance, conscious or unconscious.

The theory organizes and enlightens observed decision behaviour, but it does not explain the underlying decision process in any way.

I am familiar with this matter from automatic target detection, where the outcome of any expert system or AI deciding whether a target is present or absent can be -- ultimately must be -- studied using the signal detection theory. And then also, together with psychologists, from assessing human target detection performance versus AI, which requires the signal detection theory to be uniformly uniformly to people and to AI, regardless of their internal functioning.

The point of signal detection theory is not that an actual single decision-determining internal decision variable exists in the decision maker. The theory does not require this. The point is, as I believe Jaynes proves, that the decisions made can always be treated as if this were the case. Signal detection theory says nothing about how the decision is actually arrived at in the subject's brain.

Hi Joseph

You are doing the right things and also getting good advise as above (Miroslav N Nenov).

But... I would suggest that if you have a bridge amplifier in the lab (eg. Axoclamp 2B) that you use that instead of the 200B. Patch clamp amplifiers have the potential to introduce some distortions to fast waveforms, so if you have a bridge amplifier you will probably be better off.

see this paper:

And I think that with Multiclamp this is not a problem anymore.

All the best

Because activation of centra diencephalic structures (centrencphalic region).

I am assuming from this question that you are using the newtimef function in EEGLAB to perform a time-frequency analysis (either within the study interface or outside it). This function performs baseline correction and then averages over trials before log transforming the data for conversion into decibels. In terms of reporting a baseline, because the ERSPs that you report are output in dB it seems to me that your baseline should also be reported in dB to be comparable.

You should be able to extract these baseline values via the 'powbase' output that is returned by the newtimef function. Or in case you are interested how these values are calculated, you can also calculate them by modifying this basic script, which takes the raw output of the newtimef function (in uV) and step-by-step transforms it into the dB converted baseline:

%% Perform TFA

ScalpElecs = [13]; %% Electrodes to extract in TFA

BaselineOnset = -400; %% Onset time of baseline (in ms) relative to stimulus onset

BaselineOffset = 0; %% Offset time of baseline (in ms) relative to stimulus onset

for y = ScalpElecs %% Loop over each electrode of interest

[ersp,itc,powbase,times,freqs,erspboot,itcboot,tfdata] = newtimef(EEG.data(y,:,:), EEG.pnts, [EEG.xmin*1000 EEG.xmax*1000], EEG.srate, [3 0.8] , 'topovec', 1, 'elocs', EEG.chanlocs, 'chaninfo', EEG.chaninfo, 'baseline',[-400 0], 'freqs', [.5 20], 'plotersp', 'off', 'plotitc' , 'off', 'plotphase', 'off', 'timesout', 400, 'padratio', 8, 'freqscale', 'log');

freqIdx = find(freqs>8 & freqs<13); %% Set frequency range to extract

ERSPBaseTimes = find(times> BaselineOnset & times< BaselineOffset); %% Get baseline times to extract

Powertrialcalc = abs(tfdata).^2; %% Convert function output to (uV^2/Hz)

Powertrialcalcavg = mean(Powertrialcalc,3); %% Average data over each trial

Basetrialcalc = mean(Powertrialcalcavg(:,ERSPBaseTimes),2); %% Get averaged baseline times

PowerBaseTotal = 10 * log10(Basetrialcalc); %% Convert averaged baselines to dB

PowerBaseFinal = mean(PowerBaseTotal(freqIdx, :)); %% Average over frequencies/times in baseline

end

I use both! Check my publication list (it's not that long) on my profile page.

For reconstructions from 3D image stacks, we have been quite satisfied with the Neuromantic freeware:

https://www.reading.ac.uk/neuromantic/body_index.php

It does what it is supposed to, with no bells and whistle that complicate matters more than they help. With Neuromantic, I have put dozens of undergraduate students on the manual reconstruction work, they get their lab experience, we get our reconstructions, everybody's happy. We've done >150 reconstructions in the lab this way. Works great, but support is nil and updates rare.

I have heard good things about Fiji/Simple Neurite Tracer but never tried it. There is also Herman Cuntz's TREES toolbox (http://www.treestoolbox.org), which is more advanced. Finally, you might benefit from the option not to reconstruct at all (Ferreira et al: Neuronal morphometry directly from bitmap images. Nature Methods 2014 DOI:10.1038/nmeth.3125.).

All of this requires 3D image stacks though, so you do not work "live" like people often do with Neurolucida. However, working offline comes with advantages too.

For our work with Neuromantic, see below, in particular Blackman et al:

Blackman AV, Grabuschnig S, Legenstein R, & Sjöström PJ: A comparison of manual neuronal reconstruction from biocytin histology or 2-photon imaging: morphometry and computer modeling. Frontiers in Neuroanatomy (2014) 8:65, DOI: 10.3389/fnana.2014.00065.

Lalanne T, Abrahamsson T, & Sjöström PJ: Using Multiple Whole-Cell Recordings to Study Spike-Timing-Dependent Plasticity in Acute Neocortical Slices. Cold Spring Harb Protoc (2016) 10.1101/pdb.prot091306

Buchanan KA, Blackman AV, Moreau AW, Elgar D, Costa RP, Lalanne T, Tudor Jones AA, Oyrer J, & Sjöström PJ: Target-Specific Expression of Presynaptic NMDA Receptors in Neocortical Microcircuits. Neuron (2012) 75:451-466.

Lalanne T, Oyrer J, Mancino A, Gregor E, Chung A, Huynh L, Burwell S, Maheux J, Farrant M, and Sjöström PJ: Synapse-specific expression of calcium-permeable AMPA receptors in neocortical layer 5. The Journal of Physiology (2016) 594(4):837-861.

See this link of article

Hello!

For voltage-clamp recordings the Cs-Methanesulfonate based solution is used in our lab.

127 CsMeS, 10 NaCl, 5 EGTA, 10 HEPES, 6 QX314, 4 ATP-Mg, and 0.3 GTP; pH adjusted to 7.25 with CsOH

It allows to record synaptic currents in pyramidal neurons in slices for prolonged period of time. As it contains the blockers of potassium and sodium channels, the input resistance in whole-cell configuration is rather high (about 250-400 MOhm). I would recommend to voltage-clamp the cell at -50 - -20 mV most of the time during the experiment. Prolonged recordings at more negative voltages decrease the cell viability during the recording. This solution can't be used for current-clamp recordings.

For current-clamp recordings the K-Gluconate based solution is used:

135 K-gluconate, 10 NaCl, 5 EGTA, 10 HEPES, 4 ATP-Mg, and 0.3 GTP (with pH adjusted to 7.25 with KOH)

It allows to record membrane voltage and action potentials in pyramidal neurons in slices. However it does not perform too well in voltage-clamp mode, as the input resistance in whole-cell configuration is quite low (60-180 MOhm depending on cell type). If you use it in voltage-clamp recordings I would recommend to clamp the cell at -90 - -60 mV most of the time during the experiment.

Both of the solutions are prepared in the same manner. First we dissolve all the components in water, except ATP and GTP. After that we rougly adjust pH. Then we rapidly add ATP and GTP, make a final adjustment of pH (ATP decreases the pH) and freeze the solution in 1 ml tubes. The osmolarity of the resulting solutions is about 300 mOsm (for better patching it should be a little lower than the osmolarity of the extracellular solution).

Good luck with your experiments.

Two further, related, thoughts on this:

In relation to noise, is your study adequately powered to detect individual differences? You could do a sensitivity analysis to find out what kind of effect size you had a good chance of detecting, even though post-hoc power analysis isn't informative.

Sometimes a null finding, if the study was well powered, might be telling you that the behavioural measure and the ERP effect aren't related as you thought. You might find this paper (out shortly from David Donaldson's lab) interesting, soon out in Frontiers, although the authors don't yet know why an expected effect wasn't found, this was informative:

cheers

Alexa

Except when the symptom picture looks like celiac disease and yes taste is a sensory function, which is impaired in most autistics. If so many systems are involved then one would imagine that there was something central to all of it and labyrinthine mechanisms are not it - but part of something underneath it all. But, back to my original question which was not about autistics but all of us. What neurophysiological changes are associated with the emergence of self-identity, if any? Does body image à la Henry Head have anything to do with this?

Hi Matthew,

There is a wonderful new online metasource of rodent hippocampus-related information: http://hippocampome.org/php/index.php. There you can find tables of markers expressed in each neuron type and much more.

Enjoy!

Elena

Are you asking "what is the relationship  between brain activity and muscle activity"?  As in how do they interact, e.g. central governing model? If so, this new paper discusses some of those aspects. 

Dear Robert,

Many thanks for your reply.

I am really afraid about the work we may do together if you are available in the lab for only 1 day a week..

but anyway thanks for your interest.

Regards, manish

Thanks everybody for your responses. I found adequate methods and I thought it may help to share it.

In the case of actual EEG data, the true morphology of the clean ERP is unknown. Hence, it is not possible to rigorously evaluate the efficacy of a denoising methods with the MSE or the SNR metrics. So I used two SNR estimators to quantify the performance of the methods.

You may check this link for more details about the two SNR estimators and the results they give:

Hi!

I think the best way to normalize is to take the fft both on baseline and on the trials.

Then, you should whiten the power spectra to avoid pink-noise of the brain. (whitening means that you multiply the power value in the given frequency with the given frequency).

After that you can divide your power-spectra of the trials and the baseline into chossen frequency bands. Althought it's not compulsory, if you would like to interpret your results in each frequency, it's ok.

So, you have the whitened power spectra in the given frequency (or frequency band) of trials (Pt) and the baseline (Pb). You can then normalize them in each frequency in two ways: logarythmic and percentile-way. I will show you the percentle-way:

N=100+100*(mean(Pb)-mean(Pt)/mean(Pb))

This will give you the percentile-changes compared to the baseline. N=100 means that Pb was equal to Pt (no changes occured, N=200 means that Pt was 2*Pb.

Also, make sure that the length of baseline and the trilas are equal in order to avoid mismatches of the frequency resolution of the power-spectra. (If they aren't equal, make sure that you calculated the frequency resolution properly) 

You can find pretty good lecturelets here: http://mikexcohen.com/lectures.html, and I reccomend Cohen's book (https://www.amazon.com/Analyzing-Neural-Time-Series-Data/dp/0262019876/)  if you would like to work with EEG-analysis.

Hope I helped!

András Puszta MD

Inn addition to blocking all non-sodium currents, shorten your test pulse to 10 ms. 100 ms is too long and is suitable for calcium and/or potassium currents.

Hello everyone.

Finally our rebuttal comment has been accepted for publication in Physical Review X, almost 2 years after our first submission. We could not reproduce the observation of penetration of action potentials by the Heimburg group. Instead we consistently observed annihilation of colliding action potentials.

Further we show that their measurements of action potential velocity was flawed and indicate that their measurement electrodes were so close to the stimulation electrodes, that 1) they could not contain two action potentials 2) passive propagation may explain part of their observations. 

Also, they did not demonstrate the All-or-none property of action potentials, which again suggest that they observe either activation of multiple nerves, or they generate passive electric signals. Attached is preprints and supplementary information.

Cheers!

Rune

Essentially paired-pulse stimulus measures the short term plasticity characteristics of neurons. It is a characteristic of the probability of release of the presynaptic neuron and the type of receptors present at the postsynaptic neuron. PPR can be in both directions (facilitation or depression) and there are various explanations for what that means (as Bryan Krause mentioned).

A nice paper that goes over mechanisms for short term plasticity is: Fioravante & Regehr Current Opinion in Neurobiology 2011, 21:269–274

The postsynaptic receptor population should not have time to change during a paired pulse stimulation and if the treatment causes an effect by binding to the post-synaptic receptors, then the PPR should remain stable. While the amplitude of individual currents may be inhibited or enhanced by the treatment, the release of NT should be stable during the pulse and NT interactions with receptors should be equally effected by the postsynaptic change - thus the PPR is unchanged.

However, if the drug was interacting at the presynaptic site and changing the way the presynaptic neuron acts when it receives an action potential - its probability of release - then the way the presynaptic terminal responds to a paired pulse stimulus should also change - and the receptors see something different from before  - and PPR changes.

Its not conclusive, but a change in PPR after a drug treatment, indicates that the drug may be acting at the presynaptic side of the terminal.

In my opinion this is a good base to get an idea.

You might also look at the following article:

Versatile 3D-printed headstage implant for group housing of rodents.

J Neurosci Methods. 2016 Jan 15;257:134-8. doi: 10.1016/j.jneumeth.2015.09.027. Epub 2015 Oct 9.

I would say telemetry is for sure better

It has been my experience (see Minematsu et al, Neurology 42:235-240, 1992) that 4-0 nylon, with the proposed distal tip rounded by near-flame heating, introduced via the CCA reliably occludes the ipsilateral MCA due to size match and produces a consistent infarct size in Sprague-Dawley rats weighing 280-350 grams.

Dear Giacomo,

I have attached one of our papers on quantitative histological estimates of RGC receptive fields in the human retina. I hope you will find it useful.

Zoran

Dear Ali,

Electrical stimulation of oesophagus will likely activate both sensory and motor pathways  (axons) and therefore may not be a good model for visceral pain studies (see below). Mechanical stimulation may therefore be more relevant.

best wishes, Refik

In which case do you mean. WIth my Normal Ringer Perfusion or with the DY loding Hepes buffer oder With the K+ / D-Aspartat solution that i am using ???????

Thanks for you Answer

EthoVision® XT is a state-of-the-art video tracking system for automatically recording animal activity and movement. More information ia available here :  https://mazeengineers.com/portfolio/noldus-ethovisionxt/

Dear Vladimir! Thank you very much for your words and reference suggestions. I will read the papers and then I'll give a feedback.

Best regards,

Amilcar

Hi Mrs. Scarduzio,

we have not tested AFDX 384 but AFDX 116 at 2 µM in neocortical neurones (with various other compounds) to delineate M1, M2, M4 mACh receptor effects in neocortical neurones. We noted that the antagonistic efficacy in some cases depends upon the sequence of application. For instance, AFDX 116 prevented a CCh-induced depression of EPSPs when applied before CCh addition. Yet,  pirenzepine reversed the depression of EPSPs by CCh but failed in preventing the depression when applied before CCh. (For details see Gigout et al., 2012, Neuroscience 223, 399-.411).

good luck

R. Deisz

Mathematical Psychology if adopted to this research case that could generate some data from consumer neurophysiological decisions in some experimental or data collection means correlating to the consumer action/activity there by the generated data then could be processed using different physical/statistical methods to extract underlying pattern hence forecasting techniques could be adopted to find potential/likely judgement from consumer. Such decisions in aggregation present in cloud server helps better forecasting when a new consumer data sets arrives. It could help online the marketing guy thru information on their mobile devices about consumers mood/decision from the data processed in a could based algorithm.

A novel approach could be developed based on this theme. We have a researcher in our center working on psychological experiments and from the data we collaborate to process data & develop model to find information. We are open for collaboration if such experiment could be established so that we analyze the collected data for model development.

Regards,

Dr. Mayukha Pal

From the point of my view  important is very quick excision of brain from skull and short cooling of prepared hippocampus in ice-cold aCSF solution before cutting (cca 1 min).  McIllwain tissue chopper is quite sufficient for cuting slices for electrophysiology, we use it also. Try to set it to such speed that you can gently take each slice separately with wet brush from the blade. I also argee with the most previous suggestions and I would added that temperature of aCSF solution is suitable up to 33-34 oC during the rest of slices and  recordings in the measuring chamber.  Good luck.

Hi Yu,

Everything depends on what you call abnormal increase of calcium. That is too little information. 

I personally use 5 mM BAPTA (salt), using, of course, programs (i.e. maxchelator) to calculate the total calcium you need to use to have a constant [Ca2+]cyto, when voltage clamping skeletal muscle fibers. I generally don't like AMs  because they go everywhere inside your cells (not only the cytosol). If AM is your only possible choice, I would look for methods with concentrations and "times" for this type of loading. Be aware that BAPTA-AM could be drastic lowering not only Ca but Mg as well. 

Hi Cassey,

the short answer is yes, AAVs are able to infect axon terminals and produce retrograde transport (towards the cell body). The slightly longer answer is that this process is highly biased based on the seropype you are using. There are a number of papers reporting AAV6 (and maybe AAV6.2) is the main serotype to produce retrograde transport. There are however reports of many other serotypes producing retrograde transport with a much smaller rate. Keep in mind that there are many other considerations related to your experimental design that will help you minimize the consequences of this possible off target effect. One of the most obvious, since you talk about a cre line, is that if the axons that get infected are from a Cre- cell then the expression of your gene of interest won't take place; for example if you use a Dat Cre of a Gad Cre mouse line, terminals from pyramidal cells could be infected but they won't be able to express. Moreover, if you are interested in activate a specific cell population in many cases you apply the light stimulation (in the case of optogenetics) in the area where the neurons you infect project, and not in the area of injection itself since this approach increases the specificity of the manipulation. Finally retrograde transport, with AAV, HSV or CAV2, can be used to your advantage as it allows you to be much more selective in your manipulations. There are numerous recent papers taking advantage of this approach.

Hope this helps,

Ezequiel

Hi Aashish,

As Pieter mentioned, more information on the specific setup and issues that you are having would allow the community to give you more targeted responses. That said, one resource that I have commonly made use of when having issues with calcium imaging in a cell culture context is a methods paper from Amy Palmer when she worked with Roger Tsien (RIP).

I've attached a link. Best of luck with your experiments.

Joey

Dear Han,

beside what Refik already said about the distribution and nature of gap junctions, you seem to be confused about "inhibitory neurons acting excitatory". 

Just think about what makes a neuron inhibitory: It is the action of the transmitter at the postsynaptic receptor. Even an inhibitory neuron shows action potential, calcium influx and transmitter release. There is no difference between excitatory neurons or inhibitory neurons beside their transmitter. What is important is, which kind of ion flux is generated in the postsynaptic neurons. 

So, if you have electrically-coupled neurons (via gap junctions), action potentials or even subthreshold voltage fluctuations are "transmitted" to the connected neurons.

Regards,

Stefan

Please see the article from my e-library on the subject. Sorry. This is all what I can to help.

Hi Jan - please take a look here: http://www.cambridgeneurotech.com/wireless.htm - I can provide you with a complete solution including high-channel count wireless and a far better alternative to tetrodes too, if you're interested! Please let me know if you're interested and we can set-up a Skype call to go in to the details.

I think it is not motor shaping or self-experiencing input. Rather a delicate EPSP/IPSP dance goes on between ascending and descending inputs to insure reproduction of successful movement and not failed ones. We found that partial deafferentation by dorsal column or dorsal column nuclei lesion causes causes a permanent lose of fine finger actions. However dorsal rhizotomy from C2 to T5 results in full recovery of hand movement. This may show that unblocked sensory input becomes motor disduptive noise. Eliminate the noise and forelimb manipulative control of the hand returns to the monkey