Neurobiology and Brain Physiology

Neurobiology and Brain Physiology

  • Jonny Saunders added an answer:
    2
    Why the voltage-sensitive dye (VSD) is not effective anymore after a certain number of repeated staining of the same cortical area?

    I used to stain with VSD (RH1691 or RH1838) and record from a cortical area of the monkey brain two times a week (the monkey is behaving during the recording).

    After about three months from the first staining (and the moment the dura mater is first opened), even if the brain still looks in a good shape, I often fail to record any good signal.

    This problem persists even if I carefully remove the new transparent tissue layers that grow on the top of the cortex after the dura mater is chronically opened.

    Does anybody know why it happens and how to avoid or recover from this problem?

    Thank you!

    Jonny Saunders

    Maybe your dye is going bad? If it's been around for awhile the VSD could have bleached or otherwise denatured. You might test it by imaging it on some membrane that you can control the voltage across. If it's possible you could try to position an extracellular electrode near a cell you know is stained to compare its activity w/ fluorescence - test whether it's the dye or the cell. 

    I'm not sure about those dyes in particular, but VSD's are also commonly toxic - you might be killing cells even if the brain looks fine. If nothing else, repeatedly exposing the brain to light would result in phototoxicity. As far as I know much of the volume from lost neurons will be replaced with glia, which would dilute/degrade your signal. 

    Also, who knows! Depending on your task, the decrease in signal might just be a decrease in activity. If the monkey is mastering the task, one would expect to see less cortical activity.

  • Ricardo Salazar asked a question:
    New
    I am interested in developing/using a screening test for pre-clinical AD. What do you think about the Subjective Memory Decline Scale (SMDS)?

    " In MCI, specific aspects of SCD severity and quality are related to CSF biomarkers indicative of AD. This extends findings in pre-MCI samples and calls for an improved operational assessment of SCD in MCI. This might be useful for sample enrichment strategies for increased likelihood of AD pathology "

    Alexander Koppara et al. Neurology 84 March 24, 2015; 1261-1268

  • Rebeca Juárez asked a question:
    New
    What is the mechanism of action of BD1063 (antagonist of sigma 1 receptor)?

    Hello.

    I need know the mechanism of action BD1063. Is antagonist of sigma 1 receptor but I can't find a paper whit mechanism.

    Thanks for your time.

  • Renzo Bianchi added an answer:
    1
    May a hypothesis about engrams' structures be proved experimentally?

    I have arguments this structure is of nodal-setting kind. How much animal brain is accessible for such examination?

  • Robert Moss added an answer:
    12
    Is the role of the hippocampus in memory one of storage, facilitating cortical association networks, or both?

    AIMS Neuroscience is requesting paper submissions for our September issue. Manuscripts will need to be received by 29 August 2016, and decisions on acceptance will be completed by 29 September. The aim of this special issue is to explore the role of the hippocampus in memory. Research on the hippocampus and medial temporal cortex in memory has been extensive. The hippocampus has been proposed as both a storage location and as promoting the gradual integration of newly acquired information into cortical association networks via binding, reactivating, and strengthening connections. What are the current theories and how do these fit with long-term cortical memory storage? Please add your own answers here to stimulate interest and discussion.

    Robert Moss

    I have attached a new brief article explaining how our cortical column theory (Dimensional Systems Model) explains hippocampal involvement in memory that was described in the Moss et al. (2012) and Moss & Moss (2014a &b) journal articles.

  • Sweilem Baseem Al Rihani added an answer:
    4
    What is the best method of assessing the physical integrity and permeability of the blood brain barrier?

    I am trying to find the best way to measure the blood brain barrier permeability Invivo (Mice),I tried the Evans blue dye with High molecular weight dextran but I'm still looking for a better method to measure the changes in the blood brain barrier permeability with aging.

    Your help is much appreciated.

    Sweilem Baseem Al Rihani

    Hi Dr.Maller,

    Thank you very much and Looking forward for your review.

    Best wishes

    Sweilem

  • 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.

  • Sweilem Baseem Al Rihani added an answer:
    4
    What is the best way to wash-out the mouse brain capillaries from blood after injection of a dye for Immuno-histochemistry?

    I am trying to remove the blood from the brain capillaries after injection of a dye, I tried intracardial injection of Ice-cold heparinized PBS but I faced high resistance during the injection, so if anyone can help with a detailed protocol  to make sure that whole blood was removed from the brain capillaries this will help a lot.

    Your suggestions are much appreciated.

    Thanks

    Sweilem Baseem Al Rihani

    Thanks Dr.Gasis, 

    Yes you are right I will follow the same protocol.

    Thanks a lot

    Sweilem

  • Emmanuel Planel added an answer:
    3
    How to measure insulin resistence in rodents?

    I want to evaluate insulin resistence status in rodents,especially in the central nervous system,is there any measures I can adopt?

    Emmanuel Planel

    The hyperinsulinemic-euglycemic clamp, or insulin clamp, is the gold standard for assessing insulin action in vivo. You can see how it's done here:

    http://www.jove.com/video/3188/hyperinsulinemic-euglycemic-clamps-in-conscious-unrestrained-mice

    As this is quite complicated, another method would be to do an Insulin Tolerance Test (ITT) by injecting a bolus of insulin and recording blood glucose levels at different time points. Some authors who do not want or cannot do an ITT or insulin clamp use the HOMA-IR (Homeostatic model assessment Insulin Resistance), as it requires only a simple dosage of plasma glucose and insulin. But this test was developed for humans and there is controversy as whether it should be used in mice.

    In the CNS, it is not as straightforward, and would require analyzing the phosphorylation state of several proteins involved in the insulin signaling cascade. Plasma to CSF insulin ratio can also be an indicator. See below:

    http://www.ncbi.nlm.nih.gov/pubmed/19705099

  • Christina Ahrensmeier added an answer:
    19
    Selective astrocyte marker except GFAP?

    Hey there,

    I'm looking for a selective astrocyte marker which does not stains other glial cells, especially schwann cells. I usally use GFAP but I found at a paper, that it also labels schwann cells and a minor subpopulation of oligodendrocytes in SVZ. The same goes for the S100-Protein. I also looked up MANF (Mesencephalic Astrocyte-Derived Neurotrophic Factor) but it seems to be located to the ventral mid-brain and the substantia nigra. The astrocytes I like to stain come from the cochlear nucleus (brain stem).

    Any ideas?

    Christina Ahrensmeier

    Hey Serguei,

    thanks for the suggestions. Some are promising. It would be nice if you could provide more informations.

    best regards,

    Christina

  • Joachim Pimiskern added an answer:
    5
    What problems does the final integration of visual information present into our understanding of the brain?

    The problem of final integration has to do with how the brain binds visual information. What kinds of problems does the problem of final visual integration present in our understanding of how the brain works?

  • John Kealy added an answer:
    4
    Does anyone know which IEG activates faster in the brain? c-fos or zif 268?

    Does anyone know which IEG activates faster in the brain? c-fos or zif 268? Thank you!

    John Kealy

    I'd be wary to say there were no differences.

    It depends on the brain region and whether you are looking at mRNA or protein expression. Zangenehpour and Chaudhuri (2002) show that mRNA for both is induced along roughly the same time lines though c-fos reaches its maximal level after about 30 minutes compared to 60 minutes for zif268. However, protein translation for zif268 appears to occur faster and is more prolonged, reaching a maximum at around 90 minutes and remaining at a plateau for about 60 min. c-fos instead reaches a peak after approximately 120 min and rapidly declines from there.

    However, this data is related to light stimulation and measurements made in the visual cortex and judging from other papers out there, the time courses for different regions and different interventions vary: phencyclidine (non-competitive NMDA-R antagonist) treatment causes a phasic response in zif268 (increase after an hour followed by a suppression 1-2 days later) that was absent in c-fos yet CPP (competitive NMDA-R antagonist) caused similar changes in both zif268 and c-fos (Gao et al., 1998). Learning and memory tasks also show spatial and task-related variations in zif268 and c-fos expression (Barry and Commins, 2011) so you really need to look for any publications relating to the brain region/task you're interested in or to do some control experiments looking at fixed time points after your intervention to get an idea of the time course for certain.

    + 2 more attachments

  • Wilfried Musterle added an answer:
    32
    Why does music evoke emotions or feelings?
    Music has many bodily effects. This is not trivial.
    Wilfried Musterle

    Dear all,

    Merry Christmas to you and a happy new year.

  • Dirk Ulbricht added an answer:
    2
    Where is the primary sensory cortex for brain blood vessel smooth muscle innervation?

    It has long been argued that the brain has no sensory receptors, but the smooth muscle controlling blood flow of the intracerebral arteries clearly has sensory and motor innervation. 

    Robert A. Hill, Lei Tong, Peng Yuan, Sasidhar Murikinati, Shobhana Gupta, Jaime Grutzendler. Regional Blood Flow in the Normal and Ischemic Brain Is Controlled by Arteriolar Smooth Muscle Cell Contractility and Not by Capillary Pericytes. Neuron, 2015; DOI: 10.1016/j.neuron.2015.06.001

    Dirk Ulbricht

    I would like to highlight that the trigeminovascular reflex mediated via the tracts nucleus solitarii is essential for that, as implied in the current pathophysiological models of migraine. It may explain why a lot of patients receiving Metoprolol, beta-blocker which does penetrate in the brain, have a real benefice nervetheless.

  • Johannes Bohacek added an answer:
    3
    Which ELISA Kits are suitable for assaying dopamine and noradrenaline in rat brain sample?
    I need to assay dopamine, noradrenaline and serotonin of rat brain during my research project, but I couldn't find ELISA kits which are suitable for rat brain samples.
    Johannes Bohacek

     Hi Leila, did you ever get a useful answer? I'd also be curious to find a good ELISA to measure norepinephrine levels in different mouse brain regions. Would be thankful for any recommendations.

  • Ghulam Md Ashraf added an answer:
    5
    Is there any other specific technique to identify microglia from mice brain other than Flow cytometry?

    I usually look at microglia isolated from mice brain using the standard percol gradient method without using Collagenase/DNAse steps i.e. just meshing the brain with 10 ml syringe plunger and then layering 30% brain cell suspension on 70% percol. This is the way I look for infiltrating lymphocytes (CD45 Hi)  and microglia (CD45 Int CD11b+ cells) by Flow cytometry. The method works well for analyzing infiltrating lymphocytes but for microglia, I get the fluctuating data for the mice even within the same group. Is there any other clean and better way to isolate and characterize microglia from mice brain? Waiting for your suggestions.

    Ghulam Md Ashraf

    really nice suggestions, thanks eveyone

  • Luis Varela added an answer:
    4
    How many serotonergic neurons are there in the human brain? In how many locations/subsystems?

    By way of comparison, there are an estimated 22000 - 51000 noradrenergic neurons in the human brain - all in the locus coeruleus. How many serotonergic neurons are there in the human brain?  How many subvarients? And where can they be found? And in comparison, how many serotonergic neurons are present elsewhere in the body (eg., in the human gut)?

    Luis Varela

    Dear Prof. Schwartz:

    I attended, your lectures at the INPP Conference in Frutillar (I presented a poster on Contemporary Psychopathology Seminar for Residents)

    Regarding your question, I found this in an article by Horning JP. Journal of Chemical Neuroanatomy 26 (2003) 331–343

    The development of histological and imaging techniques has demonstrated the great homologies between the organizations of the serotonergic system in many mammalian species including human. With a total number of about half a million in the human raphe nuclei, serotonin neurons have a dense and divergent projection extending to all divisions of the brain, but still with a specific areal and cellular targeting in different circuits of the sensory, motor or limbic systems.

    Might you need further help, please do not hesitate to write (l.varela@uandresbello.edu)

    Best regards,

    Luis Varela

  • Chrystalleni Vassiliou asked a question:
    Open
    How can I choose between diphteria or different antibiotics to select monkey neurons in vivo?

    I am doing a project and I need a way to protect some cells and kill all the others in the temporal cortex of monkeys. We thought that we can use resistance to antibiotics or diphtheria toxin to do that and then inject the antibiotic/diphtheria on the area, but I am struggling to decide what is the best way to go. Could you please help me? or at least tell me what I need to consider when making my choice? Thank you

  • Sacha Bohler added an answer:
    4
    What is the average lipid content of the human brain?

    Concentrations of lipophylic chemicals in the brain are often expressed as g/g lipid. But for my experiments I need concentrations in M. In consequence, I require the lipid content of the human brain, or, more specifically, of the substantia nigra pars compacta, if available. I have been going through the literature but so far to no avail.

    If anybody could provide this information, I would be very thankful.

    Regards,

    Sacha

    Sacha Bohler

    Dear Saak,

    Thanks for the reference. I already checked it, and it did not provide me with the answer I am looking for. It is nevertheless what I have currently used as a close approximation for my calaculations.

  • Marianne Levon Shahsuvaryan added an answer:
    3
    Is there any advance in finding a validated target for sporadic Alzheimer's Disease (Not Familial or Prion related or other neurodegeneration)?

    It is a somber realization to those haven't as yet encountered and a grim fact to those who know the current and forecasted Alzheimer's Disease prevalance and impact.

    If the amyloid hypothesis is not causative but consequential, just as the cholinergic appears to be, and if no idea has been successfully translated into even a mediocre clinical benefit, how do we approach again the blank drawing board with a new hope?

    + 1 more attachment

    Marianne Levon Shahsuvaryan

    Recently due to its neuroprotective and antioxydative properties is used Minocycline - the second generation semisintethic antibiotic which penetrates blood-brain barrier

  • Luke Paul Crocker added an answer:
    15
    Is crowd funding a viable alternative now that research grant awards are at an all-time low?
    Crowd funding has been successfully used to launch many new inventions, musical and artistic projects. Will scientists now turn to crowd funding or is this merely a passing fad?
    Luke Paul Crocker

    Another platform is Patreon, at least for those that work with more artistic fields. There are many options for how to run your funding through that. I use this platform for my artistic research and practice-led research in Japanese rope bondage (shibari and kinbaku) instruction and performances.

    Basically, how I have it set up is for those that pay $10 a month, get some of the raw data (usually photographs and snippits of current data); $25 per month gets video updates including the interviews with my partners, Q&A on the current reserch and practice, etc; $50 per month gets all of the above as well as weekly writeups of current progress in the research.

    Like any crowed funding, some make it big (one example is $24,000/2 weeks), and some flounder.This, I dont think will work for just any reserch work, but for the arts, it seems to run well.

  • 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)

  • Boaz Barak added an answer:
    4
    How many inject sites for rat striatum AAV-shRNA injection?

    I am going to inject AAV-shRNA into rat striatum, cause it is relative larger brain area, do I need to inject more than one site? Thanks.

    Boaz Barak

    The volume of injection depends on your virus titration. Based on the volume and the consequent infection area you should decide how many injection sites per hole. Then choose these sites locations based on the diameter: if each injection site covers for example 1/2 of the dorsoventral axis of the striatum (and it is not. It is just for the example) then you need two injection sites, one in 1/4 of the axis length, from dorsal point of the striatum (you can measure from the corpus callosum), and the second at 3/4 of the axis

  • Anirudh Kumar Satsangi added an answer:
    4
    Are the benefits of meditation transitory or permanent? Do all types of meditation give same result?
    Yes, the benefits are permanent.
    No, the results are mostly different. There are, of course, some common results.
    Anirudh Kumar Satsangi

    Meditation results in the "conditioning" of nervous system particularly autonomic nervous syste.. 

  • Arne Brun added an answer:
    3
    Which approach is better to make Alzheimer's Disease mice model?

    I will be doing an experiment to make an AD mice model and can't figure which is better, changing the doses of AB injected, or changing the time in between the injection until tested?

    I will be using Morris Water Maze to do the testing on the mices

    Arne Brun

    dear Emma,

    recent findings conccrning differences between man and rat has disclosed basic fundamental dissimilarities between the two, e g in terms of  astrocyte organisation and relations to neurons in humans but not in rat in addition to other differences that would seem to reduce the relevance of a rat model, sorry to say. Good luck anyway, Arne Brun

  • 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. 

  • Béatrice Marianne Ewalds-Kvist added an answer:
    6
    Releasing agent vs. reuptake inhibitor?

    Selective norepinephrine and serotonin reuptake inhibitors (SNRI's) are commonly used in the treatment of cataplexy because cataplexy is the result of down dysregulated norepinephrine, itself the result of missing or greatly diminished orexinergic signaling.  

    However, cataplexy is also occasionally treated with Phentermine, which is a norepinephrine releasing agent.

    What happens when a person takes both a releasing agent and a reuptake inhibitor (not necessarily specific to this example, but generally)?  Is the result a greater concentration/availability of the protein you're after than you'd get with either individually?

    Béatrice Marianne Ewalds-Kvist

    All four are here on RG,

    R E Heikkila · H Orlansky · C Mytilineou · G Cohen,

    someone must answer you. I asked for their fulltext. 

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