Baddeley’s Model Of Working Memory
In 1974 Baddeley and Hitch proposed an alternative theory of short-term memory: Baddeley’s model of working memory. According to this theory, short-term memory is divided into different slave systems for different types of input items, and there is an executive control supervising what items enter and exit those systems. The slave systems include the phonological loop, the visuo-spatial sketchpad, and the episodic buffer .
Ventricles And Cerebrospinal Fluid
The brain has hollow fluid-filled cavities called ventricles . Inside the ventricles is a ribbon-like structure called the choroid plexus that makes clear colorless cerebrospinal fluid . CSF flows within and around the brain and spinal cord to help cushion it from injury. This circulating fluid is constantly being absorbed and replenished.
There are two ventricles deep within the cerebral hemispheres called the lateral ventricles. They both connect with the third ventricle through a separate opening called the foramen of Monro. The third ventricle connects with the fourth ventricle through a long narrow tube called the aqueduct of Sylvius. From the fourth ventricle, CSF flows into the subarachnoid space where it bathes and cushions the brain. CSF is recycled by special structures in the superior sagittal sinus called arachnoid villi.
A balance is maintained between the amount of CSF that is absorbed and the amount that is produced. A disruption or blockage in the system can cause a build up of CSF, which can cause enlargement of the ventricles or cause a collection of fluid in the spinal cord .
Imaginary Worlds Real Memories
The past few decades have also seen more researchers using virtual reality technology in their work. In recent years, Nanthia Suthana, a neuroscientist at UCLA, became one of the first researchers to use virtual reality to study how someones brain stores and recalls memories as they navigate a simulated environment.
Historically, the large majority of have been done with rats and mice running through mazes, says Suthana. A lot of what we know about the brain comes from those studies. And, in order for us to translate those and see if theyre really true for humans, we need something to connect between the two.
In two studies currently under peer review, Suthana and her colleagues worked with patients with deep-brain implants for treating epileptic seizures. The researchers put virtual reality headsets on the patients, whose permanent implants enabled the scientists to record brain waves during the experiment. Once the participants donned goggles and motion-capture bodysuits studded with reflective dots to track their movements, they then performed a series of tests on learning, memory and navigation in a simulated environment.
The brain is electrical in its language, she says. So if we can communicate with the brain, electrically, maybe we can facilitate when things go wrong.
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What Part Of The Brain Controls Long Term Memory
The study of memory necessitates the study of the brain. Memories are created in, stored in, and affected by different parts of the brain:
- Neocortex. This is the brains wrinkly-looking outer layer. It stores memories.
- Hippocampus. This is involved in converting our perceptions into long-term memories. The right posterior section is involved in spatial navigation, which, as well see, is an important aspect of memory.
- Medial temporal lobe. This contains the hippocampus and is involved with long-term memory.
- Basil ganglia. This is involved in learning habits.
- Cerebellum. This is involved in learning motor skills.
- Frontal and parietal cortices. These are involved with recalling long-term memories.
When we use our brains, they physically changewe can form new neurons and rearrange connections. This is known as neuroplasticity. For example, neuroscientist Eleanor Maguire studied the brains of London cabbies-in-training. She found that their right posterior hippocampi were 7% larger than the average persons because they spent so much time memorizing the layout of the city. This is a fascinating insight into what part of the brain controls long term memory.
Memory And Traumatic Brain Injury
- Memory problems are very common in people with moderate to severe TBI.
- TBI can damage parts of the brain that handle learning and remembering.
- TBI affects short-term memory more than long-term memory.
- People with TBI may have a tough time remembering to remember. This means remembering to do things in the future, such as keeping appointments or calling someone back when youve promised to do so.
- People with moderate to severe TBI may not remember the incident surrounding the injury.
- With the help of certain strategies, people with TBI can learn to work around memory problems and get things done every day.
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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.
The Process Of Memory Consolidation
Memory consolidation is the brains ability to process events and turn them into memories.
When certain neurotransmitters are present in the brain, they enable the nerve cells to communicate with one another via synaptic connections. Once two neurons fire together more than once, they are more likely to fire together again . Once a message has been thoroughly communicated, you have memory consolidation.
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How Are Memories Formed
The brain simmers with activity. Different groups of neurons , responsible for different thoughts or perceptions, drift in and out of action.
Memory is the reactivation of a specific group of neurons, formed from persistent changes in the strength of connections between neurons. But what allows a specific combination of neurons to be reactivated over any other combination of neurons?
The answer is synaptic plasticity. This term describes the persistent changes in the strength of connections called synapses between brain cells. These connections can be made stronger or weaker depending on when and how often they have been activated in the past. Active connections tend to get stronger, whereas those that arent used get weaker and can eventually disappear entirely.
A connection between two neurons becomes stronger when neuron A consistently activates neuron B, making it fire an action potential , and the connection gets weaker if neuron A consistently fails to make neuron B fire a spike. Lasting increases and decreases in synaptic strength are called long-term potentiation and long-term depression .
Which Part Of The Brain Is Responsible For Memory And Intelligence
So, now you may be wondering, what part of the brain controls memory?
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The answer to this question may be a bit more complex than you think. The truth is, there is no one memory part of the brain. In fact, different memories are stored in different places all over the brain
Reversible Causes Of Memory Loss
Its important to remember that memory loss doesnt automatically mean that you have dementia. There are many other reasons why you may be experiencing cognitive problems, including stress, depression, and even vitamin deficiencies. Thats why its so important to go to a doctor to get an official diagnosis if youre experiencing problems.
Sometimes, even what looks like significant memory loss can be caused by treatable conditions and reversible external factors, such as:
Depression. Depression can mimic the signs of memory loss, making it hard for you to concentrate, stay organized, remember things, and get stuff done. Depression is a common problem in older adultsespecially if youre less social and active than you used to be or youve recently experienced a number of important losses or major life changes .
Vitamin B12 deficiency. Vitamin B12 protects neurons and is vital to healthy brain functioning. In fact, a lack of B12 can cause permanent damage to the brain. Older people have a slower nutritional absorption rate, which can make it difficult for you to get the B12 your mind and body need. If you smoke or drink, you may be at particular risk. If you address a vitamin B12 deficiency early, you can reverse the associated memory problems. Treatment is available in the form of a monthly injection.
Are you taking three or more drugs?
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A Molecular Account Of Long
Eric Kandel is best known for his work on the physical basis of learning and memory in the marine snail Aplysia. This animal, simple as its nervous system is , nevertheless provides an excellent model for the study of learning and memory, through its “gill withdrawal” reflex. When Aplysia perceives something touching its skin, it quickly withdraws both the siphon and the gill, much as a person withdraws a hand from a hot stove without thinking about it. Although this withdrawal is a reflex, it is not completely hard-wired but can be modified by various forms of learning. One such form is sensitization, in which the animal becomes aware of a threatening factor in the environment and to protect itself learns to augment its reflex. The augmented version of the withdrawal reflex can also be maintained in short-term or long-term memory, depending on whether researchers administer the noxious stimulus only once or twice, or many times within a short period. The two forms of memory can be distinguished not only by their durationthe difference between minutes and daysbut also at a molecular level, because it is possible to treat the snail with a chemical compound that interferes with long-term memory but leaves short-term memory unimpaired.
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Do Patients With Amnesia Lose Their Motor Skills
Motor skills are nondeclarative. People with amnesia dont lose learned motor skills skills that require coordinated movement of muscles. Just like riding a bike is an old saying that means the learned activity is second nature easy to remember and repeat. In fact, studies by neurologists have proven that people with amnesia learn motor skills at the same rate as healthy individuals.
Normal Forgetfulness Vs Dementia
For most people, occasional lapses in short-term memory are a normal part of the aging process, not a warning sign of serious mental deterioration or the onset of Alzheimers or another dementia.
The following types of memory lapses are normal among older adults and generally are not considered warning signs of dementia:
- Occasionally forgetting where you left things you use regularly, such as glasses or keys.
- Forgetting names of acquaintances or blocking one memory with a similar one, such as calling a grandson by your sons name.
- Occasionally forgetting an appointment or walking into a room and forgetting why you entered.
- Becoming easily distracted or having trouble remembering what youve just read, or the details of a conversation.
- Not quite being able to retrieve information you have on the tip of your tongue.
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Drugs That Cause Short
Sometimes its the drug treatment for a health condition, not the condition itself, that causes memory loss.
There are many prescription drugs that list short-term memory loss as a side effect.
A group of drugs called anticholinergics can trigger short-term memory loss by blocking the action of acetylcholine, the main neurotransmitter associated with learning and memory.
Acetylcholine is also essential for turning short-term memories into long-term ones.
The level of acetylcholine naturally declines with age which puts older adults at greater risk for memory loss induced by their medications.
Two of the worst kinds of medications for short-term memory loss are anti-anxiety drugs and narcotic painkillers .
And its not only prescription drugs that can affect your memory.
Some over-the-counter remedies such as the antihistamine Benadryl are anticholinergic and have been linked to dementia.
And as you might expect, recreational substances ranging from alcohol, nicotine, and marijuana to heroin and cocaine take a toll on short-term memory.
What Kind Of Computer Is This
The types of mental representation discussed above, such as the continuous monitoring of the spatial surround by the parietal lobes, illustrate a vital point that is often overlooked when comparisons are made between the human brain and the computer. The fact is that the human brainor the brain of many other animalsis solving quite difficult computational problems at every moment, just in seeing, recognizing a voice, or moving in a coordinated fashion on four limbs, or two limbs, or two wings. Most of these problems are so complex that they have yet to be formulated in explicit terms by computer scientists, which is why machines that can perceive and move and communicate as animals doand perform all these functions at onceare still largely the stuff of science fiction.
Of course, organization is crucial to managing such a vast resource, and the brain exhibits this feature at several levels, as discussed throughout this book. Research conducted on the simpler nervous system of invertebrates, as well as on nonhuman primates, other vertebrates, and humans, has indicated how learning brings about structural changes in nerve cells and how the neurons in turn form regions, which take part in networks. The networks are organized into distributed systems, which collaborate with other systems, both sensory and associative, to produce the total working effect.
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The Locus Of The Long
Overall, the results described to this point would seem to demonstrate conclusively that the cerebellum is necessary for learning, retention, and expression of classical conditioning of the eyeblink and other discrete responses. The next and more critical issue concerns the locus of the memory traces. Evidence summarized below would seem to demonstrate conclusively that the long-term memory traces for this type of learning are formed and stored in the cerebellum.
We and our associates have developed a new approach to the problem of localizing memory traces in the brain, namely the use of methods of reversible inactivation, together with recording of neuronal activity. Reversible inactivation methods ,per se, have existed for some time and have been used very effectively to produce temporary lesions . What we have done is to apply this method systematically to the major structures and pathways in the cerebellarbrain stem circuit we have identified as the essential circuit for classical conditioning of discrete responses , during performance and during acquisition of the CR .
Inactivation of the magnocellular red nucleus is indicated in Fig.b. Inactivation by low doses of muscimol for 6 days of training or cooling for 5 days completely prevented the expression of the CR. Yet animals showed asymptotic learned performance of the CR from the beginning of postinactivation training .
Which Part Of The Brian Is Affected During Memory Loss
We already mentioned that there is not one single part of the brain that is responsible for learning or memory, so there is not a single region responsible for memory loss either.
The frontal and temporal lobes, the limbic system, and parts of the brain stem that control alertness are all involved in memory and learning. So, if any of these parts get damaged, a person can suffer memory loss or amnesia.
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Memory Encoding And Its Types
Memory encoding refers to the changing of sensory stimuli or information so that it can be stored and retrieved. The information undergoes this process so that it can become a part of long-term storage. The properly encoded information is very easy to be recalled. There are three main types of memory encoding: visual, acoustic, and semantic.
Visual encoding is converting a visual stimulus to store the information in the brain. This information is first stored in the visuospatial sketchpad. Then, it is temporarily stored in working or iconic memory before its storage in long-term memory.
Acoustic encoding refers to the encoding of acoustic information to understand the acoustic aspects of an event. It is the processing of sounds, words, and other auditory information to store that information in long-term memory. An important part of acoustic information is the phonological loop.
Information that has a particular meaning or context is processed in a way that is called semantic encoding. Concepts, Ideas, and terms are some examples of semantic information. The semantically encoded information is relatively easy to be retrieved. There are also some other types of memory encoding which may include tactile encoding, etc.
Types Of Memory Loss: Temporary And Permanent
Memory loss can be either temporary or permanent.
- Temporary memory loss is a loss of information that, after a period time without remembering, it returns to normal. For example, if you are unable to remember an actors name in the afternoon, and then remember it later that night, or if you take medication that causes blackouts, you would be suffering from temporary memory loss.
- Permanent memory loss, is when you lose memories that you are unable to recover. If youre not able to remember where you left your house keys, even after being reminded, you would be experiencing permanent memory loss.
There are several different types of long-term memories stored in your brain. These include:
- Semantic Memory
- Semantic memories are part of the declarative memory and refer specifically to knowing the meaning of words and actions. An example of a semantic memory is understanding what the word memory means.