Assembling A Brain In The Laboratory
Hebbian synapses have also been demonstrated in another kind of laboratory, where computer scientists and engineers have built them into a computer chip. The device is a simple one, with only 16 synapses, but it performs Hebbian learning quite efficiently, at the rate of a million times per second. Newer chips have already been developed to represent more realistic neurons, with many thousands of synapses and technology to represent the connections between such neurons will make the assembly of something more nearly resembling a working brain a little easier to envision. Such a device will have to combine analog signals, like those propagated within neurons, and digital signals, the off or on impulses transmitted from one neuron to another. It will not be simply a larger, or even an unbelievably faster, version of today’s familiar computer.
The field of artificial perception already boasts chips developed at the California Institute of Technology that are capable of much of the sensory processing performed just outside the brain by the retina, for example, and by the cochlea, the spiral passage of the inner ear whose hair cells respond to vibrations by sending impulses to the auditory nerve. Now in development as well are chips to simulate some of the functions of the visual cortex others, with some of the memory-storing capacity of the hippocampus, are being scaled up, closer to the dimensions of a living system.
False Memory And Memory Implantation
As much as we can trust our brain in keeping the record of everything, it can go through specific alterations. Our memories, especially the episodic ones, are reconstructed and can be falsely stored. One pop culture representation of false memory we have seen is in the movie “Inception.” Tit revolves around going into someone’s subconscious and planting the idea or memory that was not there.
Progress in psychology has proven that memory implantation is indeed possible. With therapy, the memories can be manipulated, and new memories can be implanted. We see the phenomenon of memory implant going on in ‘Westworld where AIs are given false human memories to mask their reality and purpose.
The World In The Front Of The Brain
Short-term and long-term memory are not the only forms in which the brain stores information. All the time that the five senses are operating, the brain is assembling and sorting perceptions of the outside world, directing some to conscious attention and collecting others into a set of perpetually updated mental representations. Although we may seldom be aware of the full extent of these mental representations, or examine them directly, nevertheless, they hold great importance for our thought processes and our ability to carry out the simplest planned action or predictive step, even something as elementary as following a fast-moving target with our eyes. These mental representations are the data on which we base cognitionour thoughts, ideas, and abstract mental processes.
Animals, too, form complex mental representations of the world, which are shaped by their own brain structure and ecological requirements. For instance, information gathered through the sense of smell undoubtedly plays a much larger role in the mental representations of a dog than in those of a bird, which relies much more on its excellent vision to help it recognize its kin, observe the territories of its rivals, and seek out food and mates. With such differences taken into account, the study of mental representation in animals can help scientists explain similar processes in humans, particularly if the neurobiology of the animal is also under study or is well known from earlier research.
Memories Shape Our Perception And Reality
Everything we are and everything we will ever be is all dependent on memory. Human belief systems, perceptions, and learning are all memory related. Our consciousness is the ultimate reality of us as people with personality and preferences. Memories define actions, and actions are what we become.
Suppose you think racism was not real. But you came across literature contradicting the idea. Your perception said that it was right. So, you committed the new information to your memory. Based on which you acted differently than before. Had it not because of the mind, you might have stuck to your old beliefs.
Reasons Behind Forgetting Things
The brain can store a large sum of data in it, but some things are lost. Forgetting is as essential as retaining something. It helps make new memories and move on. Otherwise, we will never progress into the future and cling on everything traumatic we remember. Sometimes we even forget the memories we cherish because this is how the brain works. It lets go of memories so future memories can be made. This is the reason why we even forget our most heartbreaking break up after a while or even our most cherished birthdays.
Here are the three ways it can happen.
This is the process of losing memory when the neuron connection weakens over time. With aging or when we do not actively recall a memory, the neuron’s link is lost. It can also happen when we lose the stimulus to the mind. The memory might still be there, but we are not able to access it.
This happens when our brain actively prunes and discard certain details of a memory. For example, when we learn a new piece of information that contradicts the previous one, the pleasant memory is retained. The conflicted one is dismissed. With target forgetting, we also eliminate our conflicted believes and welcome new perceptions.
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The Cerebellum And Prefrontal Cortex
Although the hippocampus seems to be more of a processing area for explicit memories, you could still lose it and be able to create implicit memories , thanks to your cerebellum . For example, one classical conditioning experiment is to accustom subjects to blink when they are given a puff of air. When researchers damaged the cerebellums of rabbits, they discovered that the rabbits were not able to learn the conditioned eye-blink response .
Other researchers have used brain scans, including positron emission tomography scans, to learn how people process and retain information. From these studies, it seems the prefrontal cortex is involved. In one study, participants had to complete two different tasks: either looking for the letter a in words or categorizing a noun as either living or non-living . Participants were then asked which words they had previously seen. Recall was much better for the semantic task than for the perceptual task. According to PET scans, there was much more activation in the left inferior prefrontal cortex in the semantic task. In another study, encoding was associated with left frontal activity, while retrieval of information was associated with the right frontal region .
S Of Brain Involved In Memory Processes
Technically our brain has many different compartments and they work differently to do certain functions. Not all of the brain is involved in memory. Hippocampus is the main region of the brain involved in memory processes.
When it comes to storing or making a memory Hippocampus is involved. It is the primary regulator of the process of memory retention. It is a seahorse-shaped part of the temporal lobe. It acts as a bridge in engaging all the parts of the brain required to keep a memory. Although it is not involved in retrieving, formation and consolidation are highly dependent on Hippocampus. Consolidation is the fixing or storing a memory permanently.
Suppose due to a dire turn of event someone you know had most of the part of his Hippocampus removed. This person will not be able to remember anything new. Thus, memories will not be retained. However, the ability to recall older memories that happened before removing the Hippocampus will remain unaffected.
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Neurons That Fire Together Wire Together
Back in 1906, Camillo Golgi and Santiago Ramón y Cajal had been jointly awarded a Nobel Prize for advances in cell-staining techniques that demonstrated the anatomy of a neuron.
Thanks to their work, scientists knew there were millions of neurons in the brain that pass messages to each other in the form of electrical impulses. When an impulse reaches the end of one neuron, it causes the release of chemical messengers called neurotransmitters, which pass across the gap, or synapse, and latch onto a neighbouring neuron.
This makes the second neuron more or less likely to fire its own impulse. But how these neurons formed long-term memories was still a mystery
Read more about the brain and memory:
That remained the case until 1949, when Donald Hebb published one of the most influential theories of neuroscience in the last century. He wrote that any two brain cells that are repeatedly active at the same time will tend to become associated.
Their anatomy and physiology will change so that they form new connections or strengthen existing ones. The activity in one, he said, will subsequently facilitate activity in the other. Youll often find this summarised as neurons that fire together, wire together.
Simply put, if two concepts, say the smell of a rose and its name, repeatedly stimulate their respecting neurons in the brain at the same time, those neurons will change shape and strengthen that connection.
Motor Representations Are Important For Sports
How do you learn a new sport? What would your parents or coach say? Practice, practice, practice! And as you practice, scientists think that you develop something called motor representations in your brain, which are like motor memories. Motor representations are created by groups of brain cells that interact to help you perform a movement you have learned. These representations allow you to perform better. They allow you to make the basket, slam the tennis ball, or play a violin concerto. Based upon what is happening on the soccer field, the star player can select the best response based upon her experience and the motor representations that have been developed and stored in her brain through practice. Check out this video for concrete examples of the increased speed and agility that comes with practice in cup stacking, a new Junior Olympics event .
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How Do Musical Memories Differ From Other Long
In order to form and retrieve long-term memories , multiple regions of the brain work together to form a coordinated network that transmits information from one brain region to another. For instance, when you remember what something you saw earlier that day looked like, you are using your occipital lobe, which is involved in vision. When you remember what you were thinking about earlier, or wonder how something that happened may have instead happened differently, you are using your frontal lobe . When you remember other moments in time, such as your own past , you use multiple brain regions, including both the temporal and frontal lobes . All of these different representations are put together in a specific region of the brain called the hippocampus, located within the temporal lobes, to form a memory.
Mr. Wearings brain infection destroyed his hippocampus and other nearby brain regions, causing amnesia. The famous patient Henry Molaison, known by his initials as H.M., also suffered severe memory loss after doctors surgically removed his hippocampus and the tips of both temporal lobes . By studying the cases of Mr. Wearing, H.M., and other individuals with amnesia, we can conclude that the hippocampus and neighboring regions of the temporal lobe are crucial for creating and accessing long-term memories.
What Happens In The Brain Biologically Speaking
The biochemistry of memory.
The answer to question 1 has the following important points:
We now enter the idea of Engrams. This is the theoretical construct that describes the storage of memory at a biological level. We are still searching for engrams which represent specific memories.
Engrams are interesting because they are a proposed solution and an abstraction for many problems in memory. When we look at memory from different angles such as the brains organization, neural activity, mental components, etc., we can converge onto something we can observe and measure. This is an engram. As far as we know, engrams are a little mysterious there may be dedicated engram cells in the brain or existing neurons may function as engrams.
The most surprising aspect of engrams is that there might not be a precise way to conceptualize them at the moment. Some experiments have shown that a memory can be destroyed by virtually switching of any neurons within a relevant region. So it is hard to pinpoint where the components of memory are stored. As per our current understanding, memory of single events is highly distributed instead of having a fixed place.
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Procedural Vs Declarative Memory
Procedural memory refers to our knowledge of skills and how to perform tasks, and is something we mostly remember automatically. We generally dont need to consciously think about how to ride a bike or play an instrument: we simply go through the motions once weve learned how to do it.
Multiple parts of the brain are involved in the formation of procedural memories. Once a skill has been learned, a key part of the brain called the basal ganglia is responsible for processing and coordinating the muscle movements and habitual actions required to achieve a goal.
Imagine theres a ball zooming towards your head: do you raise your hands to catch it, or do you run away from it to avoid being hit? Quickly deciding which action to take is a decision for the basal ganglia. The cerebellum, located towards the back of the brain, is also responsible for coordinating those movements.
are facts or memories of past events that can be declared rather than performed. Examples might include an important life event, who came to dinner last night, or the date of your mothers birthday, as well as information about the world. Declarative memories can be further broken down into other sub-types of memories:
From Flies To Rodents
A few years later, Hardt found something similar in rats. He was investigating what happens at the synapses of neurons that are involved in long-term memory storage. Researchers know that memories are encoded in the mammalian brain when the strength of the connection between neurons increases. That connection strength is determined by the amount of a particular type of receptor found at the synapse. Known as AMPA receptors, the presence of these structures must be maintained for a memory to remain intact. The problem, Hardt says, is that none of these receptors are stable. They are moved in and out of the synapse constantly and turn over in hours or days.
Hardts lab showed that a dedicated mechanism continuously promotes the expression of AMPA receptors at synapses. Yet some memories are still forgotten. Hardt proposed that AMPA receptors can also be removed, which suggests that forgetting is an active process. If that were true, then preventing the removal of AMPA receptors should prevent forgetting. When Hardt and his colleagues blocked the mechanism behind AMPA-receptor removal in the hippocampi of rats, as expected, they found that the rats were prevented from forgetting the locations of objects. To forget certain things, it seemed that the rat brain had to proactively destroy connections at the synapse. Forgetting, Hardt says, is not a failure of memory, but a function of it.
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How Does Replacing Cells Help Retain Memory
When a brain cell replaces another dead brain cell, what it is essentially helping us achieve is to sustain the original pattern of arrangement of the entire group of cells.
This in turn enables us to retain our memories without any issues. As an analogy, consider a computer keyboard. At first, we have a keyboard.
Lets say that at some point the enter key breaks due to over usage. Now we have a keyboard with a broken key . If we get a new enter key and replace the broken enter key, we havent altered the fact that it is a keyboard.
In fact, we have a fully functional keyboard once again. The enter key by itself does not represent the keyboard. But together as a set of keys, all the keys together represent the keyboard.
The Benefits Of An Artificial Brain
Of course, the brain cannot ever be completely characterized in terms of a computer because in addition to all its computing faculties it possesses the properties of a biological organ in a living system. But, points out Gerald Edelman of the Neurosciences Institute at Rockefeller University, computers can indeed do something that, until recently, only a brain could do: they can carry out logical functions. Today, a computer can address any challenge or problem that can be described in a logical formula. This still leaves unexplored vast areas of human experience, such as perception but as described earlier in this chapter, computer and mathematical modeling on one side, and more detailed neurobiological examination on the other side, are making inroads in this area too.
An important principle of Darwin IIIâs nervous system is that the strength of the synaptic connections can increase selectively with greater activity when that activity leads to an adaptive end. What is âadaptiveâ for Darwin III is defined by arbitrary values built into its programming. For example, the built-in principle that light is âbetterâ than no light serves to direct and refine the systemâs eye movements toward a target. Just as in living neurons, the enhanced connection provides a stronger response the next time that particular neural pathway is active.
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