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[[File:Molecular view of glutamatergic synapse.jpg|thumb|right|350px| Molecular illustration of a glutamatergic synapse, showing presynaptic vesicles containing glutamate (pink) and key membrane proteins involved in neuronal signalling. The structures are based on experimentally determined data from the Protein Data Bank, including voltage-gated , receptors, and transporters. Potassium (magenta), sodium (lime green), and calcium (cyan) ions highlight the electrochemical gradients central to neurophysics.]]
Neurophysics (or neurobiophysics) is the branch of biophysics dealing with the development and use of physical methods to gain information about the nervous system. Neurophysics is an interdisciplinary science using physics and combining it with other Neuroscience to better understand neural processes. The methods used include the techniques of experimental biophysics and other physical measurements such as EEG mostly to study Electromagnetism, mechanical or Fluidics properties, as well as theoretical and computational approaches. The term "neurophysics" is a portmanteau of "neuron" and "physics".
Among other examples, the theorisation of ectopic Action potential in neurons using a Kramers-Moyal expansion and the description of physical phenomena measured during an EEG using a dipole approximation use neurophysics to better understand neural activity.
Another quite distinct theoretical approach considers neurons as having Ising model energies of interaction and explores the physical consequences of this for various . In 1981, the exact solution for the closed Cayley tree (with loops) was derived by Peter Barth for an arbitrary branching ratio and found to exhibit an unusual phase transition behavior in its local-apex and long-range site-site correlations, suggesting that the emergence of structurally-determined and connectivity-influenced cooperative phenomena may play a significant role in large neural networks.
In the recent decades, physicists have come up with technologies and devices to image the brain and its activity. The Functional Magnetic Resonance Imaging (fMRI) technique, discovered by Seiji Ogawa in 1990, reveals blood flow changes inside the brain. Based on the existing medical imaging technique Magnetic Resonance Imaging (MRI) and on the link between the neural activity and the cerebral blood flow, this tool enables scientists to study brain activities when they are triggered by a controlled stimulation. Another technique, the Two Photons Microscopy (2P), invented by Winfried Denk (for which he has been awarded the Brain Prize in 2015), John H. Strickler and Watt W. Webb in 1990 at Cornell University, uses fluorescent proteins and dyes to image brain cells. This technique combines the two-photon absorption, first theorized by Maria Goeppert-Mayer in 1931, with lasers. Today, this technique is widely used in research and often coupled with genetic engineering to study the behavior of a specific type of neuron.
/ref> and were first introduced by Eugene Wigner.
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