Neurobiophysics

Neurobiophysics

  • Dietmar Plenz added an answer:
    What is the difference Propagating waves and neuronal avalanches?

    does anyone has some Ideas about the relationship between these two phenomena?

    aren't they the same thing with different names?

    if they are not, what is their exact difference?

    Hi Abolfazl,

    neuronal avalanches are very different from waves.  You can imagine an avalanche as a single pulse that propagates through whatever medium iwith an equal likelihood to continue or die out in the next time step/generation.  This is best modeled by a critical branching process.  the resulting avalanches form distinct spatiotemporal patterns that selectively branch different points in space.  avalanches have in common with waves that most of their propagation is carried out by local interactions, like dominos that topple and the cascade of toppling dominoes bridges long distances.  The important general aspect of avalanches is that they indicate a particular, critical state of the system which has many advantages for information processing. 

    hope that helps,

    best

    dietmar plenz

  • Hossein Hassanpoor added an answer:
    Do hippocampal astrocytes have any effect on spatial memory formation and retrieval? If yes how?
    According the effects of astrocyte in synaptic plasticity and neural function, it's not out of mind that astrocyte may play an important roles in formation and retrieval of spatial memory. But I’m looking for the related mechanism(s).I'll be appreciate who help me to finding my answer.
    Hossein Hassanpoor · Amirkabir University of Technology

    Dear Shivendra

    Thanks a lot. I had it before. That is a nice paper. please see my paper too and let me know your comments about it.

    "Mechanisms of hippocampal astrocytes mediation of spatial memory and theta rhythm by gliotransmitters and growth factors"

  • Javad Mirnajafi-Zadeh added an answer:
    What is the role of Donnan membrane equilibrium in generation of resting membrane potential (RMP)?
    I am a bit confused after reading about Donnan membrane equilibrium. In neurons, we have semi permeable membrane and a mixture of permeable and impermeable charged ions/molecules, that could lead to steady state. The asymmetric ionic gradient as well as permeability leads to the driving force/voltage across the membrane. Then, role of Na+K+ATPase is to maintain the steady state level and balance the leak of Na+ and K+ (specialty due to action potential, leak or co-transporters). My question is if we block Na+K+ATPase pump, what would be the resting membrane potential of a NEURON? will it be ZERO? Of course, we have some permeability for Na+ and CL-. What is the more dominating factor to generate RMP? is it Donnan membrane equilibrium or Na+K+ATPase pump ?

    Thank you
    Javad Mirnajafi-Zadeh · Tarbiat Modares University
    I think you could get your response with a lot of interesting mentioned responses. However, for simplicity consider that there are 3 factors in determining the RMP: 1-the most important is difference in membrane permeability to different ions (you can guess the effect of chenges in permeability of each ion by the Goldman equation). 2- Donnan effect which can change the diffusion of anions and cations inside and outside the cell. Usually it can produce a -17 mV changes in RMP. 3- Na-K ATPase pump which have a Max effect of 10-15% in some (not all of the cells). If you like to understand the Donnan effect very precisely, I highly recommend you to study the following reference:
    Kutchai HC, Ion equilibria and resting membrane potential. In Physiology (Fifth Edition), Berne RM, Levy MN, Koeppen BM, Stanton BA (Eds), Mosby, 2004, pp. 22-30.
    Please note that in more recent edition of this book, these parts have been deleted, so please try to find the 5th edition of this book. I'm sure you will enjoy its study specially pages 24-26.

About Neurobiophysics

Neurobiophysics is the study of the structure and function of the nervous system from the perspectiv

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