The brain consists of cells called neurons, that are connected by axons, a wire-like projection from the cell body. Maybe one would expect each connection between two neurons to consist of an axon starting from one neuron and ending at the other neuron. It would take one axon for every existing connection, firing signals through it back and forth. However, this is not how it works. First of all, there is only one axon, one possibility for the cell to send a message to the outside world. That axon branches and branches and in doing so forms an arbor-like object. The axon usually stretches over some distance and then branches further away from the cell body. The branch ends of an axon usually don't attach directly to another neuron. Next to the axon each neuron has on its surface a lot of dendrites, also arbor-like projections from the cell body. The dendrites are able to receive messages. Dendrites usually branch near the cell body and do not extend further away. Dendrites, just like the axon, usually don't attach directly to another neuron. Usually dendrites attach to axons: two neurons connect by an axon branch end from one cell clicking on to a spot somewhere in a dendrite of the other cell. The clicking spot is the synaptic cleft. In every connection between two neurons there is precisely one synaptic cleft. So instead of wiring connections directly, neurons connect by clicking axon arbor branch ends onto spots in dendrite arbors. Connection of arbor on arbor, as to speak. Direct links are the exception. Each axon end clicks to one dendrite spot.

A brain part copying procedure

Within 100 up to 200 years millions of nanorobots will travel through the bloodstream to the human brain. Maybe they travel in adapted cells or otherwise come to agreement with the immune system. Their target is a chosen part of the brain. Arrived at the destination the nanorobots leave their transport cell (if they have) and enter a neuron, until every neuron of the chosen brain part contains one nanorobot. Each cell then measures its precise location, by a kind of nano-gps, and send this to the computer outside.

Maybe the robot consists, amongst other parts, of a grid that spreads itself out over the inner wall of the cell. Or maybe it looks like a squid, or spider, a central spherical core and long flexible arms reaching out from it, spreading out over the inner wall of the cell. The nanorobot seeks the places where the axon and all the dendrites grow out from the cell body and puts a thin flexible arm or something like that into it. The arm is able to let the axon fire and in a dendrite it measures the incoming signals and eventually blocks them.

Next the robots in different cells make contact with each other by using the axon. One nanorobot in a cell makes the axon to fire. The signal splits at each axon branch and passes the synaptic clefts and finally reaches several other neurons. The nanorobots in the receiving cells notice the signal's arrival and send this to the computer outside the human body. The computer concludes that apparently there is a connection between the emitting neuron and the receiving neurons and in what direction signal propagates.

One by one all nanorobots execute this procedure. Over time a map (map 1) is created of the precise neural network of the investigated brain part, all cell locations, all connections between them and the direction of each connection. The person in which all this is happening might die some day, but the map of the brain part will remain.

What's in there?

It is a healthy brain part, we know that. The person wherein this is happening, is chosen for that. Elsewhere is another person with this particular brain part being wrong, e.g. damaged by hemorrhage beyond repair by the human body itself. Nanorobots let the cells of the damaged brain part die and drain off the dead cells. Somewhere else in the patient growth of stem cells is initiated that have to migrate to the the died-off and drained-away brain part. As soon as a new stem cell is formed, one nanorobot enters it. The maturing from stem cells to brain cells must wait until the cells have arrived at destination because the axon and dendrites would hinder transport. This process goes on until at destination there is an overgrowth of stem cells. When arrived at destination the stem cells are allowed to mature into brain cells.

The nanorobots in the new cells measure their absolute position by nano-gps and the computer outside creates a map (map 2) of the locations of all new brain cells. Subsequently the computer searches for every registered neuron in map 1 of the healthy person the best corresponding neuron (e.g. nearest location) in map 2 of the new brain part of the patient. From map 1 the computer decides which cells from map 2 have to make contact with each other and which connections are not desired, and also whether there are too many or too little new cells. Too many, then note which cells have to disappear. Too little, then order for more new cells.

As soon as the new cells had arrived at location, each cell is incited to develop as much as possible dendrites near the brain cell, so the cell can receive messages. A real overgrowth of dendrite ends. The nanorobot also incite the cell it is in to develop the axon and the axon is incited to branch as much as possible and spread over as much as possible space. A real overgrowth of axon branch ends.

Now everywhere axon branch ends from one cell meet dendrite arbor spots of other cells and at those places a synaptic cleft is formed. This should be a natural process. There is meant to form as much connections as possible.

When this is ready, another army of nanorobots outside the brain cells search for the newly formed synaptic clefts. At each cleft is positioned one nanorobot. The nanorobot enters the cleft with one flexible arm that is able to see a signal passing through it.

Then the nanorobot in a newly wired neuron incites its axon to fire. The nanorobots in a number of other cells register the arrival of that signal. Also the nanorobot at the synaptic cleft of these connections registers the signal passing. The computer outside concludes that the connections between our signaling cell and the receiving cells exist and notices the direction of each signal. It also notes which synaptic clefts corresponds with the connections (although is unknown yet which synaptic cleft belongs to precisely what connection). This action is performed for each of the new cells.

Map 2 is nearly ready now. The computer outside compares the observed connections of map 2 (including their direction) with the known connections between the corresponding cells in map 1 and decides which connections in map 2 had to be prolonged, which had to be removed and which are still missing, in order to form a copy of map 1. These planned adaptions are noted in map 2. When a connection between two cells is present but in the wrong direction, this connection is noted as to be removed.

Then the axon in a cell is made to fire again. The nanorobot at the cleft of one of the axon arbor ends deliberately hinders the functioning of the cleft just enough so that the nanorobot in the receiving cell sees the receiving signal being hindered. Now the computer knows that this cleft belongs to the connection between that two cells. This is performed for all the clefts in all the new cells. Now map 2 is completed. The computer outside now knows from each synaptic cleft to which connection between two cells it belongs and uses the planned adaptions of map 2 to judge Yes, this connection must be continued or No, this connection should be removed. When Yes then the nanorobot at the cleft puts a yes-mark on the synaptic cleft. When No, the nanorobot at the cleft puts a no-mark on the synaptic cleft.

The computer has also registered a number of missing connections. It now has to judge whether the current situation will satisfy or that somehow (a number of) the missing connections yet have to be made. If the latter, then it will start a completion process.

The proper axon arbor of a missing connection (mind its direction) might have a number of no-clefts in it. Now the computer directs a nanorobot at such a no-cleft to break the no-connection by drawing the axon end apart from the dendrite spot by means of its flexible arms, and guides the axon open end toward a dendrite spot of the cell with which the connections is wanted. The axon end is incited to form a synaptic cleft at the dendrite spot, this should be a natural process. The robot at the cleft replaces the no-mark by a yes-mark.

When the proper axon of a missing connection has no no-clefts left to guide, then we have a problem. Maybe it will be possible for an unwanted connection elsewhere that is marked no, to clip it out and transport it to the place of the missing connection. I guess it will be possible to clip out only the axon part from an unwanted connection. The clipped axon part has to move to and grow on the axon of the wanted connection. The other open end of the axon part is guided to the proper place on the proper dendrite, is put onto it and should form there a synaptic cleft. I guess it is no option to clip the no axon part from where it branches off the axon and clip the dendrite part from where that branches off the dendrite, while maintaining the synaptic cleft in the clipped nerve segment. It may also be possible to clip out an axon part or dendrite part without a synaptic cleft from other no connections, that then can be inserted to elongate an axon or a dendrite. Maybe open end boxes can be used during transport. Open end boxes are small boxes put over axon and dendrite branch ends, see Open End Axons at page 6 of EXISTENCE.

When this is completed, the outside nanorobots are told to search for all residuent no-marks and clip off the synaptic cleft there in such a way that the open ends will not form a synaptic cleft elsewhere again.

If the computer judges Brain part copying process completed, then the axons of the newly made cells are incited to fire until the connections are strong enough. Prolonged firing strengthens the connection, especially the synaptic cleft, this is a natural process.

Then the new brain part, when it succesfully has grown in and all connections with other brain parts and organs etc. are made, will start to adapt to the older brain parts around it and vice versa. Using connections will strengthen them while prolonged blocking of a signal will make the connection to disappear over time. This is a natural process, the use it or lose it property. Or maybe the adaption can be guided more or less. You, or others around you, might experience your brain slowly changing over time until this natural adaption process has been completed, which may take days, weeks, months or years.

Wrong genes too

Suppose we have a brain disease in which not only the brain structure has grown wrong, but also quit a number of genes are doing a lot of wrong things. Let's suppose, in order to cure the disease, it turns out to be useful to replace a brain part in the patient by a healthy brain part structure. Then before the multiplication of stem cells is initiated that have to mature to the cells of the new brain part, the nanorobots first enter one (or some more) of those stem cells, one nanorobot per cell, and head for the nucleus. No spreading out over the cell's inner surface yet. They penetrate the nucleus with their long thin arms and intrude the DNA. One by one they manually replace wrong pieces of DNA by right pieces, handed over by nanorobots outside the cell that reach inside with an arm. Where necessary they synthesize DNA on the spot, until finally a proper functioning brain cell has been made. All this might take place somewhere else in the body, after which the new stem cells migrate through the blood vessels to their destination before they start to mature. The new brain part will be made of healthy cells.

Maybe there also are diseases where only the cells are wrong, not the already formed connections. Then the procedure is still the same, except for that there is copied onto itself with repaired cells, instead of a copy from somebody elses brain part.

When the repaired cells are more or less mature brain cells already, then the cells have to replicate before the axon and dendrite arbor development. I guess the arbors cannot be duplicated in a normal cell division process and it may be the arbors that form the main reason why brain cells in adults do not multiply anymore. I don't think dragging along complete arbors through blood vessels is an option and one cannot know at that faraway place the shape of the arbors on forehand, not mentioning how to connect the open ends of axons and dendrites at their proper places.

The key to reality. All of reality.

Up until March 2020 I didn't knew each neuron has only one axon. I thought each connection between two neurons always existed of an axon directly going from one cell body to the other. A brain cell would have as many axons as it has connections. The brain part copy was meant to be created by a real bunch of new brain cells and an overgrowth of connections between them as much as possible. Subsequently the unwanted connections would be cut away, leaving the structure of the original brain part.

It took me 5 years to formulate an answer to the single axon and the branching of axons and dendrites: not only one nanorobot in each neuron but also one nanorobot at each synaptic cleft.

June 2025

Previous attempt 1
If the axon is fired sufficiently long by the nanorobot in the cell, not only the wanted connections are strengthened but also all the unwanted connections that the axon arbor makes. If one blocks the connection from the other side, blocking the appropriate dendrite by the nanorobot in the cell with which the unwanted connection exists, then not only the unwanted connection is blocked but eventually also a number of wanted connections with other cells that ends in the same arbor of the blocked dendrite. That was after I realized there were axon arbors and dendrite arbors. But before the use of nanorobots at synaptic clefts.

Previous attempt 2
Maybe the target cells that are nearby can be incited by their nanorobots to release a chemical attractant that makes the mentioned axon to branch and grow towards that cells. To avoid intermixing of neighboring target cell attractants, leading to a lot of unwanted connections and a lot of missing wanted connections, maybe different types of attractants can be used for (all too) neighboring cells. However, for target cells further away this will not do, using attractants to seduce over long distances. Maybe then a nanorobot outside the cell releases the chemical attractant just in front of a developing axon branch and guide it towards the far away target cell. All this is very laborious and feels quite insecure.

Something is missing

So there seems to be no way for a neuron A to send a message to only one specific neuron B. If neuron A send a message to neuron B then via the branches of the axon of A the message also reaches other neurons C, D, etc. If, with the use of branching axons and branching dendrites, one wants to connect solely neurons A and B by one signal, one has to follow the signal from neuron A through the axon and at each branching somehow specify which direction to go and which not.

Another possibility would be that the synaptic clefts were adjustable so that neuron A can make all synaptic clefts at the end of all its axon branches to block the signal, except for the synaptic cleft that connects with neuron B. When arriving at the proper dendrite by passing the synaptic cleft, the signal certainly will end at the desired neuron B.

Maybe there is another system, used only for blocking synaptic clefts when necessary. Another system, next to the well known neuron system, that doesn't go from brain cell to brain cell, but from synaptic cleft to synaptic cleft. Synaptic clefts not only become larger when used often and become smaller when used less frequently, which is a kind of opening-or-blocking too. But the clefts might also be used as switches, in fact transistors, putting the connection between two neurons on or off at will, the will coming from e.g. another brain part. The clefts are used to immediately rewire the brain structure for special purposes.

Subsequently B wants to send an answering signal back to A and to A alone. Therefore one of B's axon branch ends has to end in a dendrite of A. Then B must know where A is, which branches of its axon must be blocked and which has to be used, in order to reach A. Maybe in the baby stage of the person neurons A and B fire to each other during a sufficient long time until the connection is strong enough to persist. Brain cells could be ordered in pairs.

I wonder how nanorobots will copy the extra system.

News

Investigations show that more than 200 neurotransmitters have been uniquely identified.

In 2023 an atlas has been published of brain cells. It distinguishes 3313 cell types, distributed over 461 categories. The map includes which gene set is linked to which cell type and where the cell types are located. Especially the brainstem contains a hugh number of brain cell types.

I didn't read the atlas yet, I don't follow the news on brain cells very well. As far as I understand there has been little investigation yet on how between different cell types synaptic clefts form and what neurotransmitters are involved then. If we only had those nanorobots.

Conclusions

1) The brain part copying procedure can start for the first time when nanorobots can enter a cell body without disturbing the functioning of its content. Brain cells and all other kind of cells. Not expected before the year 2200.

2) I would call the procedure elegant because a) It constructs the new brain part from cells of the own body, no inserting of cells of somebody else, no foreign cells; b) The procedure is independent from the location of the copied brain part, deep parts are just as approachable as surface parts; c) Nanorobots do the work and the new cells migrate to the new spot before they connect anyhow. There is no surgery needed into the brain to draw away old brain parts or insert new brain parts.

3) The copying of brain parts seems a routinely process, that can be carried out by a computer. One doesn't have to understand the brain part one wants to copy, one just copies its structure. The only demand is that the brain part is localizable. One must be able to decide which cells belong to the wanted part and which cells do not. A little is said in brain part overlap (between the two flower-like β-pictures at the previous page of THE DIRECTION OF TIME).

4) I guess in a lot of cases it will not be necessary to copy a whole brain part. In a lot of cases it will be sufficient to adjust brain properties, like number of axons, emitted amount of neurotransmitter, genes methylizing, and so on. The nanorobots have a lot to do and a lot to learn how.

5) With these two things together, the brain part copying procedure and the brain adjusting process, my guess is that it is possible to cure - if not prevent from occurrence - autism, depression, fear, psychosis, addiction and schizophrenia. In combination with the growth of new organs (see next page of EXISTENCE) mental ill institutions, nursing homes, hospitals and prisons will become quit empty. There will hardly be an opportunity left to study the illnesses in real life.

6) In whatever stage of your life you are in, when you're done with your own brain and like to have a new one for a while, it is just possible - although for this surface transmitter boxes might be more appropriate, see paragraph Open end axons at page 6 of this storyline. Whatever damage you do to your brain, when you carefully mapped its original structure you will be able to restore your old natural state, if you choose so.

7) We can choose the structure of our own brain, our existence. In my opinion this is an advantage, however it depends a little on what we choose then.

8) The brain part copying process is not the solution to everything. E.g. the process itself is not creative. It only copies. But if creativity is in a brain part and if you copy that brain part, you will still have copied creativity. We will see.

Discussion

1) How much time will a typical brain part copying process take? And how does the subsequent adaption process evolve in the course of time?

2) The process so far assumes that the location in dendrites where precisely the synaptic cleft is, plays no role. This assumption might be wrong, especially in the memory. We will have to wait until we see.

3) Different types of brain cells might need different brain copying procedures.

4) Does one (partially) think with its DNA?

5) How much of the brain's mind activity happens IN the cell body of the neuron (but outside the nucleus)?

6) If a brain part is altered just a little bit, e.g. at some location the number of existing neurons is enlarged, do the cell nuclei notice this and take measures and restore old condition?

7) Are all brain functions well separated? If so, what is the shape of the brain parts? Connected points, lines, planes (layers), lumps? See also Brainpart-overlap ... at the previous page in THE DIRECTION OF TIME storyline.

8) First I thought, they can make nanorobots in the way computer chips are made. But one needs flexible robots that can do things, not only rigid chips. Maybe printing will come to the rescue, printing nanorobot parts atom by atom. Will the nanorobot be made of carbon structures like buckyballs, will the grid be made of graphene?

9) Energy supply. For the nanorobots, carrying a battery along seems no option, just to massive. There is plenty of energy in the body, one only has to find a way how to use it.

10) Is such a robot able to send a signal to a computer outside, or will it use a relais-nanorobot nearby that amplifies the signal and then sends it to the computer?

11) The nano-gps is of course not a real gps transferred by satellites. There might be one gps signal source mounted on the skull, or something like that.