Nothing! The little bit that I searched on this year's Nobels in Physiology or Medicine identified several other blogs with similar questions. While I don't disagree that this is extremely novel work, the impact it will have on the clinic is minimal.

While the work of O'Keefe and the Mosers was powerful and novel, there is a bit of a "so what" factor to this. I mean, we encode the environment we live in, with cells that fire action potentials in space. We perceive sounds, we see, we feel and touch with cells that encode the environment. So it was no surprise that those types of cells would be there. In fact this is the demonstration, yes, those cells are there. Is this revolutionary? Not really.

What I find difficult to comprehend is why others did not get considered (Buzaski; McNaughton; Barnes; and others)? These guys  have identified age-dependent changes (size tightness of the cells'  perceptive field, etc...loose maps,.. etc) in these cells and that I think, is more therapeutic and clinically relevant (for a Nobel in Medicine).

I hope to offend no one with these comments, as I know there are probably many computational neuroscientists here that live and breath place cells.

Finding different types of neurons for which the increase of firing activity has meaning for us is well known in neuroscience.

In 1948 Konorski found single units that responded selectively to a specific image of a familiar object and  called them “gnostic” neurons. Based on temporal patterns (firing rate) other types of neurons were found: place cells, grid cells, mirror neurons , concept cells, expert neurons ....Buzaski; McNaughton; Barnes; Graybiel, Koch and others

In the late sixties Jerry Lettvin a brilliant scientist from MIT suggested that one neuron- one concept makes little sense. As a criticism he coined the term grandmother cell.

By chance, ten years ago we found that action potentials recorded from the same neuron are not stereotyped signals   which proves that Lettvin was right

http://dx.doi.org./10.1016/j.jneumeth.2005.05.006

http://dx.doi.org./10.1016/j.jneumeth.2006.05.003

Importantly,  the existence of place cells does not prove temporal coding. The same temporal pattern can encode different things, different behavioral semantics, see the example of going either left or right on the T-maze http://precedings.nature.com/documents/61/version/1%29

This simple example proves logical inconsistency of firing rate or interspike interval as a measure of semantics. 

Later, we found a similar phenomenon in medial temporal lobe (human brain http://www.sciencedirect.com/science/article/pii/S0165027012001021?v=s5 ) It shows that in the brain information is electrically integrated from many cells which store fragments of information for different presented objects

In addition to non-stereotyped electrical wave propagation  the diffusion of molecules should be also non-stereotyped.Modern microscopes can be used to probe such behavior . I’m confident that new measurements in vivo will soon detect that such non-stereotypy plays an important role also in hippocampus where the recorded unit (neuron) should store just a fragment of  the "place" engram. 

With stereotyped action potentials computational neuroscience developed a mathematical model of spherical chickens in a vacuum http://www.youtube.com/watch?v=StHMKdvuHN0  

Like in physics we need a different theory to understand how the brain works it will  also show us what kind of experiments are required.

In fact we all recognize that such neurons (place cells, grid cells, mirror neurons , concept cells, expert neurons...) store information, however they store only fragments of the engram.Since spikes are not stereotyped signals Lettvin was right all along.

I was pleased to see a Nobel Prize go to Neuroscientists once again, but was a bit surprised with this year's selection. For example, among many, is not the discovery of plasticity in the Hippocampus at least an equally seminal discovery? In any case, I would like Dorian to expand on his ideas of 'spikes are not stereotyped signals' and 'neurons only store fragments'... What are you saying? That these so called place cells don't  really code for place, or they do only partially (rather obvious), or that they can in other circumstances also code for something else. Please explain... This is actually one of the best potential discussions I have fallen upon on this site :) Thanks

Place cells : What does it prove?

Of course it proves nothing, as no scientific finding ever proves something. However this is a seminal finding that has revolutionized the field of Neuroscience. Moreover, together with grid cells it is very much worthy of the Nobel Prize.

Why is it worth the Nobel? As Olivier writes above "the impact it will have on the clinic is minimal". I don't completely understand how he could speculate that far into the future - we are many times unaware of the impact of a scientific finding. Did Einstein know that E=MC2 will subsequently lead to the atomic bomb? Thus talking the way Olivier talks about the finding smells to me as journalism, and not as a scientific estimate.

Some people have noted here that there were larger achievements, such as LTP. I am sorry to say that LTP is a nice idea however there is still very little proof about how much is it really connected to most types of  learning. Thus I do not think Bliss and Lomo are more worthy of the prize than O'Keefe, Moser & Moser.

We are living in an era where methods dominate over science. No one argues why someone should get a Nobel prize for inventing the Fluorescence microscope, or for inventing the Blue LED. However when basic science is at stake, people have much more to say. I am quite sure Karl Desseroth would  win the Nobel prize one day for Optogenetics and Clarity, however this does not mean that Systems Neuroscience should not get some prizes on rare occasions.

Olivier writes: "We perceive sounds, we see, we feel and touch with cells that encode the environment. So it was no surprise that those types of cells would be there. ". But this IS revolutionary. The point is that sounds and sights are directly related to the senses. Here we talk about an internal representation of place, unrelated directly to the different sensory modalities. Thus there seems to be an abstract concept which is coded here, not just shapes and colors.

The prize in not usually given to systems Neuroscience - actually looking at the list of previous winners in Neuroscience, the prize has previously been given to systems Neuroscience in 1981, when Hubel, Wiesel and Sperry were awarded for their seminal discoveries. Thus the prize has not been given to this field in the last 30 years !

It is easier to say something on the level of behavior, and it is easier to say something at the level of single cells, however connecting between levels, managing to say something meaningful at the level of the neural network, in connection with behavior is extremely hard.

So what makes the grid cells and place cells outstanding?  They are a system of cells, with a very rich phenomenology, allowing us to look at this region of the brain in a quantitative manner. The wealth of related phenomena (theta, phase precession, replay, prospective coding, remapping, layer-organization, to state some), allows us to research this system at a level of details never before possible in the mammalian brain. The discoveries of Hubel and Wiesel in V1 were great, but were done in an anesthetized cat, without any strong proof till this day that things are completely similar in the awake animal.

To sum up:

(1) The achievement is in the wealth of the phenomena

(2) The amount of new detail allows a description of the neural network, which is much more detailed than possible in any other mammalian higher brain system (retina and olfactory bulb are peripheral - so I am not counting them here)

(3) The discovery sets grounds for demonstrating the neural correlates of a cognitive map in the brain.

(4) prizes in Systems Neuroscience are very rare - because it is hard to achieve systematic discoveries, similar to those achieved at the single-cell level.

(5) Grid cells and place cells are basic science - applications are less important in this context. It is hard, though, to predict whether there will be applications derived from this research. I personally believe there will.

You have made some good points. However, temper your writing, as I never claimed that Bliss and Lomo's discovery was superior to O'keefe's et al. I merely posed a question. In any case your assertion that LTP or more generally synaptic plasticity has not been shown to be of functional consequence in learning is overstated. Kandel pretty much got the Nobel for this... and his classic work on Aplysia, for which apparently he did not get the Nobel, does make a near 1:1 link between synaptic plasticity and simple forms of learning...

Charles, I apologize of mis-citing you above. Although LTP is controversial (I don't think you will argue with that), it is a very important finding, and I believe it is a good candidate for Nobel. No need to ask the question who deserves more, really, as both are deserving. Perhaps Tim Bliss will get the prize some day.

Thanks Dori. I genuinely posed the question for discussion... On a different note and for the record, Hubel and Wiesel did not get the Nobel prize for their discovery of orientation selectivity. It was for their work on critical periods, plasticity... And Importantly the great experimentalist Roger Sperry was co-recipient that year for his long standing work on plasticity, adaptation etc. Lastly, perhaps the Nobel committee was also wrong to attribute the prize to Kandel a few years ago

Indeed, in addition to many other fragments of information it's more likely that such cells store only a part of information about “the place” .

Even though in electrophysiology (neuroscience) action potentials are described as a change in the membrane potential, in physics, electrical engineering they will always be (non-stereotyped) electrical waves. Information encoded (written) within neurons/ synapses at a molecular level is “exported“ synaptically and non-synaptically (wirelessly in both cases) during action potential propagation and all this information is electrically integrated in the brain (see neuroelectrodynamics)

In addition, one can predict that a certain place cell can become a mirror neuron in only a few days of training. Plasticity  is a very useful process. So it make no sense at all to store the entire information about “the place” in a single unit . The place cell doesn’t tell “ I’m here” it tells only the first “h” from “here” http://neuroscience.technion.ac.il/researcher/17

In order words one cell doesn't provide the entire engram.

A good theory can always save time, money and experimental effort. Lettvin solved everything with a simple thought experiment, so did Einstein and completely reshaped physics

It’s sad to find that after fifty years of research  in neuroscience Lettvin was not understood.   That's a sign that we need  a  new theory and honest scientists with vision  and  more importantly courage to reshape the field.

The  mathematical model of spherical chickens in a vacuum   http://www.youtube.com/watch?v=StHMKdvuHN0 was not random choice  

Sorry for moving back up a little bit in the discussion to points raised by Dori. Let me apologize for commenting, perhaps, rapidly on a subject I am not that familiar with. And by the way, none of us is arguing that the work of O'Keefe and the Mosers is non other than exciting and brilliant. It has provided impetus and movement in the field for computational neuroscience.

Perhaps, that's just it though, a series of rules about neurons firing in response to the space around us. In my opinion, this is not revolutionizing, because it was always expected. Neurons fire in space and certain areas respond to salient cues around us. The internal representation of place is dependent on the outside world. I do not see how this is unrelated to sensory input. Can you get place cells firing if an animal is stationary and in a completely dark maze?

I might have emphasized the Medicine part a little much when I commented on the lack of clinical application. I guess this year, the Nobel was for the Physiology component only. Still, I find it hard to believe that new pharmacological approaches will be derived from the work of O'Keefe and Moser and Moser. It is a little like the fMRI grant that is very cool technically, but has no hypothesis. We'll learn about the connections between x and y. Can we deliver a bio-available drug specifically to the prefrontal cortex and the insula to help the elderly and Alzheimer's patients? Nope.

Again, the stuff is cool, and the discussion is engaging. I will let Dorian go back to his ideas because I think they are really great. Imagine that, the action potential in one cell may encode fragments of the engram across an array of cells.

This makes me think of holographic memory...

BTW, Dorian the spherical chickens in a vacuum is funny.

Olivier, je pense que tu fait allusion au fait que cette découverte est dépourvu de 'mechanismes' dans le sens mechanismes physiologique... et je suis d'accord c'est plutot phénomologique comme découverte, mais c'en est bien une. I will continue in English as is appropriate for the wider audience. What I told Olivier in the language of Moliere is that he rightly points out that the discovery, and it is a discovery, is phenomenological in nature and not mechanistic, id este no physiological mechanisms were unraveled to explain the phenomenon... By contrast take, as another example, the work of D.A. Robinson, the man single handedly established oculomotor neurophysiology. He invented a method to measure eye movements with magnetic coils, determined and quantified oculomotor muscle properties and the main forces the muscles have to deal with in moving the eyes, developed a linear model of the plant (the system that is controlled) from which sensible predictions about single neuron discharge properties could be made, in particular  for the motoneurons, developed methods for recording from the CNS, etc. It is too bad that the Nobel society still does not recognize lifetime achievement as much as punctual discoveries. Lastly, and this is my last word on this topic, might Kandel have something to do with this year's  Nobel prize - rumor has it that he had much to do with his own award - and more importantly why was Jonathan Dostrovsky co-discoverer of the place cells with O'keefe not awarded the prize?

"Can you get place cells firing if an animal is stationary and in a completely dark maze?"

Yes, sure you can.

In some case you can get the same grid cells and place cells that fire in light to fire exactly the same in the same dark room.

The idea is that memory is involved - we pattern complete, using the hippocampus, the cues for where we are in space according to partial information from the senses. However some of the information, received from the entorhinal cortex, is geometrical in nature (i.e. the system of hexagonal grid cells).

"it was always expected" - to some extent I agree, being a neo-Kantian myself.

However - there is a difference in science between expecting something and actually proving it. Moreover, I do not think the hexagonal form of the grid cell firing patterns was ever expected.

Dori’s last answer and the idea that memory is involved gives me a good access to the topic. I appreciate that grid cells and place cells fire exactly the same if the animal is stationary and in a completely dark maze.

Place and grid cells are most interesting phenomenon. They fascinate me since I realized the surprising similarity between the hexagonal ‘grid’ in the hippocampus and the ‘grid’ of the horizontal cells in the retina. (See: The Mosaic of Nerve Cells in the Mammalian Retina, H. Wässle and H.J. Riemann Proc. R. Soc. Lond. B 1978 200, 441-461 doi: 10.1098/rspb.1978.0026)

Accordingly, my personal attempt to explain this similarity is that the place and grid cells might act as resonant participants in some kind of ‘ultimate map’ (the last step) of the retinotopic path situated in the hippocampus. This means that grid and place cells may be responsible for something like an unconscious (unaware) point-to-point duplicate of our ’seeing’. In that case, the firing of the grid cells and place cells might have similar or at least comparable bio-chemical and electrophysiological effects on the formation and reconstruction of visual memory as the firing of the retinal cells. In our thoughts and dreams they should be able then to resonate to endogenous waves and oscillations and reconstruct stored ‘pictures’ without involving the retina. What do you think about this idea?

Ursula

Dori, thanks for correcting me on that. So, if you can see that sometimes, some of the cells continue to fire in darkness while an animal is stationary, this means 2 things to me.

1) cells that continue to fire (probably at different frequency) in darkness and immobility are not mapping the environment and are just part of the noise, or, as Dorian would say, they are part of the engram, of the moment, of the "h" in the "I'm here".

2) at the instant of recording these spikes in darkness with a stationary animal, the animal was using prior stored information to map the previously learned space and was remembering where it was. Still given the massive entorhinal input from the olfactory bulb, you'd have to prove the animal wasn't making an olfactory map.

Look, we all agree, we make maps, small maps, large maps, parts of maps and as Ursula just mentioned, retinal maps. (Hi Ursula, and thanks for bringing your physics background of waves and resonance to the table). It's great!

I think Dorian is on to something with the part of the map being stored across an array of communicating neurons (and by the way, I totally agree with that premise). How could one single neuron encode an episode in our life. That's not possible. I predict that grid cell maps (physical size) change in size with an increase in frequency of firing through the network. Anybody modeled that?

Thanks Olivier for taking my retinal-map idea into friendly consideration! How about both! The retinal map in addition to the ultimate olfactory map (downstream of the bulb) in the hippocampus! Why should the animal’s brain not construct an olfactory map if each corner of the maze smells different? There might be some cheese corners and some fresh fruit corners.

As we know, all our senses have topographic maps. Maybe they all end in, or at least cross, the hippocampus? For the olfactory system we know this is the case. I would even like to believe in an auditory map in the hippocampus as ultimate stage of the tonotopic path – the basilar membrane’s point-to-point duplicate – in the hippocampus. I don’t know if such an ultimate auditory map has been already described in the literature. (Unfortunately, I am not very familiar with the hippocampus.)

The entorhinal cortex as the ‘end of the flagpole’? I think this would make ‘sense’. There all senses can ‘sum up’ their ‘information’, add the endogenous wave, and then construct and endogenously re-construct a nice holographic memory!

Once I could smell smell cigars in a nightmare. And I am living in a non-smokers home. (It is an unpleasant reminiscence of my childhood.) When I now close my eyes, while being aware of my senses, I can see a cigar with my ‘inner eyes’, but I cannot smell it. But in my nightmares I could smell AND see it simultaneously. There must be some resonance in my brain which even exceeds my conscious imagination. And in this resonance very many of synchronously firing cells from more than once sense are involved.

I am fully convinced that one single cell will not even encode an ‘h’. But the assembly of many cells might be able to tell me ‘I’m here’. One single neuron doesn’t show grandfather. But may be an array of cooperating point-to-point ‘duplicates’ of retina cells in the hippocampus (place cells ???) can, perhaps in combination with the smell of a cigar?! I am convinced that we always need more that one ‘sensory duplicate’ to resonate for recalling memory. Why should they not meet or get ‘woken up’ in the hippocampus before they emanate through the brain? Then we only need the endogenous waves and oscillations – maybe coming from the brain stem – to induce resonance, construct and re-construct holograms. But this exceeds the scope of our discussion here.

Dori wrote “retina and olfactory bulb are peripheral - so I am not counting them here”. But how about their (possible) point-to-point duplicates in the hippocampus? These are not longer ‘peripheral’! This point-to-point duplicates in the hippocampus do not necessarily have to produce identically the same kind of waves. It is sufficient if they produces the same impact to the brain.

Now I take the risk to open a new barrel: Any ‘information’ that enters the brain from the outside world can be described as waves and oscillations. They are further processed within the brain as waves and oscillations. All these waves do not ‘encode’ information – neither Shannon- nor von-Weizsäcker- nor any other information –, THEY ARE THE INFORMATION. If the brain is able to endogenously reconstruct the waves and oscillations from the outside world in a reasonably similar way then the reconstructions can be ‘perceived’ as coming from the memory. And holograms are not more and not less as stored waves and oscillations. Why not brain waves and oscillations?

Any ‘information’ entering a camera to get stored on a photographic film or on a CCD array is light waves. Any information entering a device for producing optical holograms is coherent light waves. So optical holography as an analogy to describe the memory in the brain is much more than ‘spherical chickens in the vacuum’. And the best news: there is no esoteric required!

Ursula

Since I’m embarked on the greatest challenge in neurosciences I'll start this time with a joke http://www.youtube.com/watch?v=AEIn3T6nDAo

Even one records  only  the envelope of  an action potential, every action potential carries “imperceptible endogenous waves and oscillations” and resonances  generated by molecular structures (see Ursula)  .Indeed, for us  they are imperceptible however such waves are not so imperceptible for surrounding neurons and synapses.

Since during an action potential the structure inside the neuron vibrates (resonates) information embedded within molecular structure (e.g. proteins) is carried by electrical waves. A similar phenomenon occurs during synaptic activities, vibration (resonances), electric waves and a flow of ions is generated.

The fact that a part of a neuron “vibrates” stronger than other parts during an action potential is extremely important. Such process can explain how different information can be read out from the same cell. A meaningful change in spike directivity proves this phenomenon http://en.wikipedia.org/wiki/Spike_directivity. http://precedings.nature.com/documents/61/version/1

Many things can be explained in terms of energy efficiency in the brain (again physics !) Oliver your prediction is likely to be correct, the first part should be an increase of firing rate and "God is in details" it's a dynamic process

A) Searching Phase.

An increase in frequency of firing corresponds to  neuronal recruiting when the rat moves in a novel place. Recruiting new cells is required to gather together new pieces (fragments) of information from different neurons. The searching phase is  in space http://precedings.nature.com/documents/61/version/1

Firing action potentials is energy- consuming and part of this energy will shape the molecular structure inside recruited cells and synapses . The recruited cells will become place cells. During this searching phase spike directivity points randomly in space and different parts of the neuron are activated 

see a similar dynamic process in ‘expert neurons’ (fig 4.)

http://precedings.nature.com/documents/61/version/1/files/npre200761-1.pdf

B) Specialized place cell

Once these recruited cells become place cells their firing rate will slightly drop leading to sparse firing . Less firing, less energy is needed, an efficient process, adaptation. Probably with a single spike a part of the engram can be read out . Importantly,  in this case spike directivity points in a clear direction , a certain zone of the neuron becomes more active since it carries the required fragment of information e.g. "h"  from "I'm here" (see Fig 4 http://precedings.nature.com/documents/61/version/1)

or  a similar process in the MTL http://www.sciencedirect.com/science/article/pii/S0165027012001021?v=s5

Dori can probably check this change of firing rate however, Dori cannot discriminate what parts of an engram is stored in a place cell. Such information is embedded in spatial modulation of action potentials (waves) not in firing rate changes (e.g spike directivity http://en.wikipedia.org/wiki/Spike_directivity) 

In other words, matter within the neuron and synapses is represented by their meaningful waves and these waves carry information (see Ursula).What we have called matter inside neurons (e.g. proteins) is energy, “whose vibration has been so lowered as to be perceptible to the senses” -Einstein.

@Charles indeed, sadly “no physiological mechanisms were unraveled to explain place cells” and we all know from Mircea Steriade the importance of the whole (intact) brain. An underlying physical mechanism in terms of vibrations, waves from physics  offers plausible simple explanations for place cells, grid cells, mirror neurons....Again, it seems that Einstein got it right.

However, probably the most interesting/intriguing (less studied phenomenon) is when neurons do not fire action potentials. Prior to seizure generation for about 2 min cells in the epileptogenic foci do not fire action potentials http://www.sciencedirect.com/science/article/pii/S0165027011003335 (contrary to common belief and several claims of heterogeneity in neuronal activity prior seizure generation). Unraveling “physiological mechanisms” that make cells not to fire for about 2min will be probably rewarded one day with a Nobel prize.

I liked  for this phenomenon another simple explanation from physics. 

Kolmogorov Arnold Moser (KAM) theory and its extensions can explain the presence of resonances and persistent chaotic dynamics during about 2min in the epileptogenic foci. Such simple ‘mechanistic’ explanation for local dysfunctional regulation of neuronal activity can 'bring disgrace' on a team (see Daniel Shechtman) however I still feel that it is the right kind of wrong we may need today in neuroscience until “physiological mechanisms will be unraveled”.

Physics offers simple explanations, always felt unbiased – not a physicist myself, just learnt physics from Dr Cooper..... http://www.youtube.com/watch?v=n38eAO3ne8M

We need to back up a little as I feel a bit like Penny (thanks for the funny links - great show).

I am stuck on spike directivity. You need a tetrode or several tetrodes?. What is the distance between surface recording areas on the tetrode? I understand why single electrode won't get you more than a 1 or a 0 but how do you derive direction?

You get a vector for each spike. This represents the direction the action potential traveled in 3D?

You need a tetrode or several tetrodes?.

You need a single tetrode (four recorded waves) to compute spike directivity, http://neuroelectrodynamics.blogspot.com/p/spike-directivity.html however from ten implanted tetrodes probably only one tetrode will be with all four tips close enough near a cell and have less "noise" in the recordings

What is the distance between surface recording areas on the tetrode?

Between tips about 20 micrometers, it works even in the human brain if the electrodes are close together

How do you derive direction?

Using triangulation and a singular value decomposition algorithm, one tip is the reference everything is explained , see http://www.sciencedirect.com/science/article/pii/S0165027005001743 even better in Neuroelectrodynamics http://www.iospress.nl/book/neuroelectrodynamics/

You get a vector for each spike.

Yes, in general for each spike one will get a single vector

This represents the direction the action potential traveled in 3D?

The direction is in 3D, however it is over the selected reference which is a point

Importantly it can work also with electrodes implanted in the human brain if they are close together, that's how I found that the same cell responds differently for Jennifer Aniston and differently for the spider (meaningful information is not stored only in synapses!) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3636996/

Many scientists still enjoy a casual relation with the truth and I completely understand that this technique can "bring disgrace" in neuroscience where single electrodes get only 1 or a 0.

If a few scientists start to research further this issue I predict this part

http://www.youtube.com/watch?v=tbFYokpA2ho

 it will change neuroscience forever.

A simple explanation for spike directivity 

We hypothesized that during an action potential a charge moves in space (it generates a wave see Ursula). Since this movement induces a current in each wire using triangulation one can determine the position of the charge. For each recorded quadruple (V1, V2,V3,V4) a position in space (x, y,z) is determined. Singular value decomposition is used to find a line in space that better approximates the position of these   'charges'  obtained during the propagation of an action potential.

Having a reference in space ( one tetrode tip)  is extremely useful, one can perceive that action potentials are not alike, that the spike is not 1 or 0

Good stuff, thanks for the links, I am slowly catching up.

So why assume the change in charge motion is mediated by proteins and perhaps intracellular waves?

I think if you consider the anatomy, the axon won't move between the Jennifer Aniston picture and the cat picture, however, the backpropagating action potential might divert through the dendritic tree in a direction that is dependent on the input.

Could spike directivity be dependent on that?

The charge motion is just a model (a metaphor ) which is useful to detect the change of the waves in space. 

We record only low frequencies with our devices (e.g. many filters and 30 KHz the sampling frequency) . In reality the electromagnetic spectrum generated by a neuron is large far beyond what we are recording.Higher frequencies are generated by smaller structures (Again, thanks Dr. Cooper!)

see

Fraser, A., & Frey, A. H. (1968). Electromagnetic emission at micron wavelengths from active nerves. Biophysical journal, 8(6), 731-734.

Cifra, M., Fields, J. Z., & Farhadi, A. (2011). Electromagnetic cellular interactions. Progress in biophysics and molecular biology, 105(3), 223-246.

Only two waves are included in their model (forward and backward) in reality the action potential is composed from an infinite number of waves with smaller amplitudes than those two.

Since meaningful information is electrically (wirelessly) transmitted  in the brain it makes sense to see different parts of the neuron vibrating strongly,  they embed fragments of information needed to form the  engram

That high frequency reference is super important because Ursula and I were wondering what frequencies could be used to put the engram down into space.https://www.researchgate.net/post/What_frequency_would_be_best_to_get_high_spatial_resolution_in_the_brain_structure_to_detect_the_waves_and_coincidences_using_electrophysiology

Since after all, a cell is part of a circuit, and as you know, part of more than one circuit.

Space (inside the brain) is important to consider if the holography theory of Landfield is right. https://www.researchgate.net/publication/263888839_A_neuroholographic_model_of_memory_Theta_rhythms_facilitation_and_calcium_channels

Chapter A neuroholographic model of memory: Theta rhythms, facilitat...

I completely agree,  that high frequency reference is super important, that's the main reason we can see a meaningful change in spike directivity

Landfield is right as many others  Lettvin, Shechtman....  The experimental proof  using spike directivity  was presented in http://www.ncbi.nlm.nih.gov/pubmed/22480985

Meaningful information is electrically  (wirelessly) inferred at the network level in the brain  to generate a better discrimination of presented images.

I really like Ursula Ehrfield's comment that the waves are the information: though I'd replace information by percept. But I have to try to clarify Dorian's comments:

(i) It's certainly true that we can't detect signals at frequencies about about 15KHz because we're sampling at 30Khz: but to state "the action potential is composed from an infinite number of waves" sounds a bit like Fourier analysis. Yes, there's higher frequencies present, primarily because the high speed of Na+ and K+ ion transport at the axon hillock and nodes of Ranvier. But it's not infinite.

(ii) And yes, I'm quite sure there's much more going on in neurons than spiking (there's lots of non-linear summation on dendrites - and anyway synapses are not simply electrical, but a mix of ionic movement, and chemical reactions). And the inter-molecular reactions (which is what's really happening at the molecular level is undoubtedly a whole lot faster.

But: where does that leave the original question, which was about what place cells prove? The big difficulty is getting one's head round the relationship between the ionic/electrical/chemical (or even quantum) reactions that certainly take place in neurons/synapses/dendrites *and* the first-person (or even first-rat) percepts. Place cells show that there are certainly clear connections between firing behaviour and some relatively high-level environmental information.

But I'd note that we detect firing because we can - we can detect summative electrical signals (summative over the actual ionic movements) between about 0 and 15Khz. But the question about the relationship between what's the relevant phenomena for percepts, and what we actually measure remains open.

Meaningful information in this case can be considered percept,  no issue .

Theoretically,  the idea of a large number of waves with smaller amplitudes

is supported by a continuous Fourier analysis (not by FFT) and it serves the purpose here (not one wave, not two waves....).

There is strong experimental evidence for THz vibrations during AP generation (Fraser & Frey 1968; Cifra et al., 2011).Importantly, the terahertz vibrations reflect what happens at a molecular (protein) level where meaningful information is stored in neurons and synapses (Tonouchi, 2007;  Heyden & Havenith,  2010)

Tonouchi, M. (2007). Cutting-edge terahertz technology. Nature photonics, 1(2), 97-105.

Heyden, M., & Havenith, M. (2010). Combining THz spectroscopy and MD simulations to study protein-hydration coupling. Methods, 52(1), 74-83.

In addition, it is unlikely that a cell can generate vibrations in KHz and THz bands and nothing between. If we are not able to record such vibrations it doesn't mean they do not exist.

Indeed, “lots of non-linear summation on dendrites, neurotransmitters ionic/electrical/chemical (or even quantum) “ however action potentials were considered stereotyped signals since 1914 (see lord Adrian, 1914) .

Contrary, to this general belief action potentials are non-stereotyped events. During an action potentials some parts of the cell exhibit stronger vibrations. Such phenomenon revealed by computing spike directivity reflects changes in behavioral semantics http://dx.doi.org/10.1038/npre.2007.61.1 or a meaningful object recognition http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3636996 .

The occurrence of such electrical patterns within the cell http://neuroelectrodynamics.blogspot.com/p/spike-directivity.html during an action potential generation can be easily explained as a physical process of wave interference in which at least two waves superpose (Again, thanks Dr Cooper!) 

And I really like Oliver's comment that “a cell is part of a circuit “ that “space inside the brain is important” it finally shows that Landfield was right all along.

It is very sad that after a century in brain research  one can ignore everything reinforce (Adrian’s view) digital dogma  of 1 and 0 and safely play Pennyhttp://www.youtube.com/watch?v=n38eAO3ne8M

I like to respond to Leslie Samuel Smith’s answer as well as to Dorian’s and Olivier’s by introducing my recent essay that I published on RG a couple of minutes ago. It’s quite long, sorry! But Olivier and Dorian know it quite well. By the way, I am suprised that nobody who might follow our discussion complained to my crazy observation that place cells may remind to retina cells. Is it too silly? Ursula

I agree with Leslie that we are now far removed from the original question, but we have morphed into a new blend of fields between Neuroscience and Physics. Somebody organize a meeting...

Ursula, here is a link to your document: https://www.researchgate.net/publication/268035659_An_Attempt_to_Describe_Memory_as_a_Hologram_of_Brain_Waves_and_Oscillations_Essay

I think that retinal maps and environmental maps and auditory maps probably all use similar architecture. So no, it is not silly.

Article An Attempt to Describe Memory as a Hologram of Brain Waves a...