- #1
Eagle9
- 238
- 10
Hello people
I guess that this is quite fantastic question/idea, but perhaps some day it will be possible to do it
So, in brain we have got the cortex and the axons that leave one certain area in cortex and enter another area: cortico-cortical afferents/efferents. Some certain amount of time is needed to cover this distance and to propagate the signal/information between these two areas (from A to B). When the signal arrives at destination it will be processed and will be sent to another place. This is simple and clear.
But in brain we have a huge amount of neurons and especially synapses. So, the signal goes from area A to area B, but area B can receive many other signals as well from other neurons/nuclei/structures. But the time when certain signal arrives at area B depends on the length of the axon, right? Shorter axon, earlier the signal will arrive there. Longer the axon, later the signal will arrive there. So, brain’s overall performance highly depends on time when the signals arrive at certain areas.
It means that alongside brain’s other characteristics it is very important white matter’s length(es), more precisely ratio between their length(es). Perhaps we do not change neurons’ overall number in brain, but if we change axons’ length (some of them will become longer, some will become shorter) then brain’s overall performance will be drastically altered.
What these axons’ length depends on? It depends where these two areas are located in the brain, more precisely if these areas are located at the visible/upper part of the cortex or are they folded down into grooves. We know that more than two-thirds of this layer is folded into grooves.
Why this latter circumstance is so important?
Let’s imagine two areas in cortex, A1 and B1 and both are located down in grooves and hence they are invisible and they are connected by cortico-cortical connections and signal flows from A1 to B1. Image below:
Now let’s imagine that these two areas are located on the visible surface of the cortex and they are again connected by cortico-cortical connections and signal flows from A2 to B2. Image below:
What is the difference between these two situations? The difference is that in the first case the length of the connections is approximately twice less and hence twice less time is needed for transferring the signal.
Now let’s imagine (quite fantastic) situation where the whole cortex is “turned upside down” in the sense that the areas that originally were located on visible parts of the cortex they were sent downwards and they are invisible now, they are inside the grooves. And the areas that were originally invisible they were sent upwards and they are visible now. It means that length(es) of all cortico-cortical connections will be changed, some will become longer, some will become shorter. Therefore, the time needed for sending signals from one certain area to another area will be changed as well. The order of processing virtually all signals will be altered and brain’s whole performance will be very different.
I wonder to know what mechanisms determine which areas in cortex will be visible and which will go down in grooves? Can we artificially change them in monkeys for example? What do you think, their behavior will be really changed?
I guess that this is quite fantastic question/idea, but perhaps some day it will be possible to do it
So, in brain we have got the cortex and the axons that leave one certain area in cortex and enter another area: cortico-cortical afferents/efferents. Some certain amount of time is needed to cover this distance and to propagate the signal/information between these two areas (from A to B). When the signal arrives at destination it will be processed and will be sent to another place. This is simple and clear.
But in brain we have a huge amount of neurons and especially synapses. So, the signal goes from area A to area B, but area B can receive many other signals as well from other neurons/nuclei/structures. But the time when certain signal arrives at area B depends on the length of the axon, right? Shorter axon, earlier the signal will arrive there. Longer the axon, later the signal will arrive there. So, brain’s overall performance highly depends on time when the signals arrive at certain areas.
It means that alongside brain’s other characteristics it is very important white matter’s length(es), more precisely ratio between their length(es). Perhaps we do not change neurons’ overall number in brain, but if we change axons’ length (some of them will become longer, some will become shorter) then brain’s overall performance will be drastically altered.
What these axons’ length depends on? It depends where these two areas are located in the brain, more precisely if these areas are located at the visible/upper part of the cortex or are they folded down into grooves. We know that more than two-thirds of this layer is folded into grooves.
Why this latter circumstance is so important?
Let’s imagine two areas in cortex, A1 and B1 and both are located down in grooves and hence they are invisible and they are connected by cortico-cortical connections and signal flows from A1 to B1. Image below:
Now let’s imagine that these two areas are located on the visible surface of the cortex and they are again connected by cortico-cortical connections and signal flows from A2 to B2. Image below:
What is the difference between these two situations? The difference is that in the first case the length of the connections is approximately twice less and hence twice less time is needed for transferring the signal.
Now let’s imagine (quite fantastic) situation where the whole cortex is “turned upside down” in the sense that the areas that originally were located on visible parts of the cortex they were sent downwards and they are invisible now, they are inside the grooves. And the areas that were originally invisible they were sent upwards and they are visible now. It means that length(es) of all cortico-cortical connections will be changed, some will become longer, some will become shorter. Therefore, the time needed for sending signals from one certain area to another area will be changed as well. The order of processing virtually all signals will be altered and brain’s whole performance will be very different.
I wonder to know what mechanisms determine which areas in cortex will be visible and which will go down in grooves? Can we artificially change them in monkeys for example? What do you think, their behavior will be really changed?