Introduction (What is the Hippocampus?)
I. Development and Structure of Hippocampus
A. Hippocampal Ways
B. Physiology and Chemistry
E. Diseases – Dementia and Alzheimer
Hippocampus is a layer of gray matter, which lies along the floor of the inferior horn of lateral ventricle. Phylogenetically, it is one of the most ancient portions of the brain.
Hippocampus receives a lot of afferent fibers, directly or indirectly related to all senses. These sensorial fibers leave the hippocampus via the fornix. Fornix, which is consisted of myelinised fibers, terminates in the thalamus, hypothalamus and septal area. This implies that there are various cycles between the hippocampus and subcortical areas. Additionally, hippocampus is in connection with a lot of distinct parts of the brain via subcortical areas. Presence of these ample connections implies that hippocampus takes place in many brain functions despite the believed restricted role only in odor, till about fifty years ago.
Limbic system, has an important role in transformation of actions to the behavioral form, and receives a great deal of signals from the hippocampus. Additionally, hippocampus has an important role in memory, especially short-term memory and it is impossible to keep verbal and symbolic memories when its functions are impaired.
While many questions are still awaiting for answers in human history, hippocampus functions represent an important subject that cannot be ignored. Perhaps, each brain component may have a function related to hippocampus.
I. DEVELOPMENT AND STRUCTURE of HIPPOCAMPUS
The hippocampus, part of the choroid fissure cavsis develops in the outer. This process; a pioneer in the area of neurons (neural progenitörler) begins with the proliferation and migration to. Thus, on the one hand, it thickens the wall, on the other hand, the hemisphere of the ventrik makes a bulge toward the medial edge of the ülün. This bulge in the hippocampus. The Hippocampus; the lower lateral ventricle along the base of the Horn, about 5-8 cm long, with a layer of gray matter. At the lower part of the face facing the ventricle convex, the Minister’s face is konkav. It is wide and flat-front “pes hippocampi” takes its name. This section contains two or three similar superficial no bulge. These ridges are called digitationes hippocampi. All aksons from your own cells formed by the ventricular surface of the hippocampus alveus is covered with. These fibers are in the form of a flat band medially approached the fimbria hippocampi, Fimbria hippocampi’s White the front end of the uncus gyri hippocampi ore. If the rear end with the crus fornicis alveus. The fibers to come from inferior FORNIX Alveus marks the beginning of the fimbria.
Cornu Ammonis representing the initials of the CA can be expressed as the hippocampus, CA1 CA2 CA3 cell structure changes due to different areas, such as the CA4, and divided. One of them is a gyrus dentatus subiculum to CA1 to CA4 closest to the field.
Histologically; starting from the surface deep into the layers of ventricular okay sorted now:
1- Alveus: Subikulum and includes the pyramidal cell aksonlarını belonging to okay.
2- Stratum oriens: With the pyramidal cells of the basal interneurons settled mainly on the dendritleri layer. Here most of the neuron axons alveus fibers. Most other cell axons located deep in the molecular layer.
3- Stratum pyramidalis: The characteristic of this layer as a large pyramidal and Golgi type II cells are. The base of the pyramidal cells in the hippocampus is directed towards the ventricular surface and basal-apical dendritleri extends to the adjacent layers. Axons from the stratum oriens is through alveus fibers. It is an array of the pyramidal cells here that the actual shape, okay. Link to yosunsu fibers. According to other primates is more pronounced in humans is not available in the fields of CA1 and CA2.5- Stratum radiatum
6- Stratum lacunosum
7- Stratum moleculare: Thin nerve fibers and a very small number of neuron that contains 5. 6. And 7. layers of the stratum moleculare by some authors as a single under the name of the layer, while some sources state 6. and 7. layers of the stratum lacunosum moleculare in the name.
A. Hippocampal Ways
The Hippocampus; -indirect, though-all sensory alerts containing afferentlere. The entorhinal area will be forwarded to the following four ways of the senses from the okay:
1. Perforant ways: Entorhinal cortex along the gyrus dentatus advances to subikulum, and the axons CA4 field except all okay.
2. Mossy fibers: Gyrus dentatus CA3 area from expenses.
3. Schaffer collaterals: CA3 and CA1 pyramidal cell extensions from extending the CA2.
4. Alvear fibers: Okay this subcortical areas from fibers of hippocampus CA1 and from switches and alveus subikulumun inner layer disintegrates. The hippocampus, parahippocampal gyrus and warnings and alerts hormons which FORNIX via corpus Reuben-l, the area septalis, and some of the hypothalamic nukleuslara posts.
Also the hippocampus via the FORNIX differentiated keratinocytes devoid anteriores thalami, area hypothalamica posterior, corpus septalis, the substantia innominata mamillare, area, the ventral tegmentum area and raphe nucleus receives fibers from the differentiated keratinocytes devoid parabrachialis.
The FORNIX is the largest efferent hippocampus. The hippocampus is approximately 1.2 million, and the beginning and subikulumdan myelinated fibers, passes to the fimbria hippocampi from the alveus. These fibers under crus fornicis splenium corporis callosi,, thalamus, corpus fornicis continues as the behind of. A cross between the fibers of two crus commissura hippocampi (Lyra Davidis, psalterium) is called. Corpus fornicis extending axons, columna fornicis name after, in front of the foramen interventriculare curve by making differentiated keratinocytes devoid anteriores thalami nucleus lateralis dorsalis thalami to fibers (postkomissural fiber).
Most of the fibers extending from the corpus of the hypothalamus and ventromedial hypothalamus in mamillare nukleusunda ends. Columna fornicis fibers of the anterior fornix of the allocated to commissura from (prekomissural fibers) is the area septalis, the substantia innominata and area hypothalamica rostralis to pass.
Refers to external links is usually the Papez circuit circuit of the hippocampus. Classic Papez circuit Circuit respectively; hippocampus, fornix, tractus thalamicus anterior corpus mamillare, gyrus cinguli, mamillothalamicus, parahippocampalis, differentiated keratinocytes devoid gyrus and hippocampus neurons that links back to the covers.
Papez circuit Circuit in the alerts, such as billiard balls, a feeling that we live traces each other repeatedly hit by increasingly severe and causes him to sign. Emotional reactions to this circuit must be intact.
Both the hippocampus; komissural means connection. In addition, studies on the degeneration method, neokortekse direct routes were identified in hippocampus
Physiology and Chemistry
Hippocampus monoaminerjik, cholinergic, GABAerjik afferentler. For example: Glutamate and aspartate, hippocampus is known as the excitatory transmitter is secreted. Somatostatin-immünoreaktif fibers, stratum lacunosum and stratum oriens. Glutamate decarboxylase (GAD)-immünoreaktif fibers, stratum radiatum, and stratum oriens pyramidalis, in the stratum; colesistokin (CCK)-immünoreaktif fibers is shown especially in the stratum pyramidalis. Besides; CP mossy to within an opoid
peptides of the dinorfin, many hippocampal areas VIP (vasoactive intestinal polypeptide) are common.
The consolidation of the information held as close to the memory of sleep REM phase occurs. In this phase, okay, pointing to the serotonergic rafe nukleusları active. Asleep while the regular rhythm of the EEG recordings and shows neokorteksteki, the hippocampal EEG records desenkronize.. In the case of neokortikal records desenkronize although alertness; the hippocampus shows a slow and regular rhythm. Hippocampus EEG waves are sinusoidal waves of rhythmic theta. This condition is associated with spontaneous activity and the structure shows different circuits of consciousness.
The Hippocampus; the type of the relationship is a long-term synaptic LTP (long term potentiation) and ischemia is a quite notable issues such as selective sensitivity. Another feature is also the hippocampus hipereksitabilite. For example, the mild electrical impulses, the hippocampus regions of the warning will cause local seizures lasting seconds after. This also indicates that it was emitting a long, even under normal circumstances, signals from the hippocampus.
Hippocampus and the complexity of the structure, as well as the close relationship with many in the brain region, function, make more difficult. Therefore, instead of defining the functions of the hippocampus alone in order for his stand on the role of the complex will be correct.
Hippocampus, until 1948, was about the only scent. But then some people developed normal hippocampus, olfactory pathways developed. Anatomist their studies on this subject, the hippocampus is not parallel with the development of olfactory bulbusun development. Almost every kind of sensory stimulation (sight, hearing, smell, touch, internal organs, senses, etc.), even if a small area, it will activate the hippocampus. The hippocampus and ventral to the thalamus, the hypothalamus sends signals to other parts of the limbic system. Thus, the transactions affecting the limbic system and hippocampus, before going to the behavior, contributed to shape behavior.
For this reason, in addition to the sensory signals from the hippocampus, a channel can be considered the role played in the inside. Hippocampus memory, especially short-term memory is known to be associated with. Short term memory refers to the capacity of the new information is stored. Therefore, regardless of the mechanism, without the left and right hippocampus, verbal or symbolic, it is not possible to have permanent long-term memories. On the other hand, in the right hippocampus visually, left hippocampus is verbal memory and more functions related to the activities of these regions is evolving the creators of lost related lesions.
The endocrine function of the hippocampus. For Example; Hippocampus neurons that concentrate on the front area of the östradiolü. The stimulation of the hippocampus in rat experiments with ovulasion inhibition occurred. The disorder has been identified with the truncation of ACTH also reduced inferior fornix.
Hippocampus is considered that functions also attended: sensational reactions, or the regulation of the activity of internal organs and control the thrill, the cerebral cortex is the reticular setting for an activity.
In General, stimulation of the hippocampus with anger, calm, or hiperseksualite any one of them is raised. Even after a couple of seconds the light stimulating the stimulation of an epileptic seizure. These seizures during individual smell, vision, hearing, touch, and similar style defines the hallucinations. The individual is conscious and knows it’s not true hallucinations.
In 1939, Klüver Bucy, a large part of the temporal lobe and the monkey as studied by behavioral changes to bilaterally. In 1950, in the human medial temporal lobe into parts of hippocampus two-sided with similar findings, after the removal of a significant memory loss. Klüver-Bucy Syndrome, the symptoms of this table, called in general are as follows:
1. Pliability. Horror-a sense of resentment.
2. Changes in nutritional habits. After checking the food for a long time in the polls and can work to eat non-food objects, too.
3. Psychic blindness condition occurs. That cannot be the meaning of objects.
4. Hiperseksüalite (and sometimes vice versa). Genus, species, without distinction between the sexual activity, often live, lifeless.
5. They can’t obtain new skills and new things memories.
Metabolic (alcoholism, chronic malnutrition, or thiamine deficiency) or mechanical (myocardial infarction, bleeding or surgery) as a result of the new two-sided lesion hippocampus, for reasons related to a State of amnesia memories that would make it has Korsakow Syndrom (Dismnezik Syndrome). These patients got sick before he learned ” complex jobs. But it’s much more simple, but cannot apply the learned new skills. Also called imagination or confusion regarding the history of confabulasion tells the answer, or even absurd experiences, the style that they believe in themselves or.
Until recently, the process of aging, the number of cells in hippocampus was significantly reduced, which in turn was thought to be caused by dementia in old age. However, recent studies as a result of hippocampal cell loss with aging, there is a statistically significant correlation was found. Just, Alzheimer’s disease hippocampal CA1 people, CA2, and CA3 pyramidal cell reduction in the number of areas have been identified.
Changes in behavior resulting from lesions of the hippocampus and cortical sensory stimuli are responsible for the information being interpreted.
GABAerjik the inhibitory neurons causes the decrease in the death of inhibision. This reduction, especially in CA3 pyramidal and dentate granule cells leads to pathological hipereksitabilite. Also the hippocampus seizures, depending on the underlying molecular mechanism of cell deaths, glutamate receptor subtype type NMDA (N-methyl-D-aspartate) and intracellular communication with neurons in the eksitotoksik mechanism is likely the most powerful mechanism caused the death, but the death of neurons, though fully elucidated. Seizures, many hippocampal neuron c-fos (cellular oncogenic genes) as one of the early gene expression of c-fos and recurrent severe, causing seizures, delayed some hippocampal neurons dying is stimulated. This last opinion, c-fos gene expression in neurons can contribute to his death.
Some studies of vitamin B deficiency and alcohol, damage to the neurons has shown that in hippocampus. In addition, formaldehyde-induced neurotoxicity caused by being exposed to the gas is formaldehite irreversible death reasons for investigating employee as a result of an excess of brain cancer deaths in epidemiological studies, the effects of formaldehyde obtained raises curiosity about the process, okay.
Diseases – Dementia and Alzheimer
Geriatric international literature available to people age 65 and older. Those of the general population over the age of 65% compared to the 2000 data, Turkey ratio from 5.2 to 4 million over 60 years old is about 5 million (1). These figures are for the year 2000 12% of the United states of the European Union for the year 2001 12% 18. 45-60 of middle age, young or old, 60-74, 75-84 in middle-aged elderly aged 85 and above is defined as the elderly
Geriatric age group population in developed countries, is an important part of the population. This ratio is expected to increase in the coming years. Applications will geriatric hospital patients, regardless of health problems, health spending is increasing exponentially due to co-morbid diseases in geriatric patients with this condition present in
the early diagnosis of diseases, and increases the importance of preventive medicine.
Evaluation of the patient is a geriatric age group time. Therefore, overall health, neurological or psychiatric assessments, internal controls, except for the diagnosis of certain diseases or symptoms, but also by the medical staff that can be applied to help, as short as possible, standard and sensitive evaluation tools are needed.
Dementia is a general name for many diseases beaten at the forefront of forgetfulness. Dementia is one of the common diseases in the elderly. Alzheimer’s is the most common type of dementia is Alzheimer’s disease as defined by the German scientist. Advanced stage Alzheimer disease or dementia in advanced dementia in our country, which is wrong and unpleasant words are used in a definition. Hacettepe University, Department of Internal Medicine Geriatrics Unit assessed in 2003 to 1255 in the elderly, clinical geriatric assessment, Geriatric Depression Scale, MMSE (score Minimental review), time plotting test activities of daily living, instrumental activities of daily living, 14% as a result of laboratory and radiological investigations , 4 dementia (Alzheimer-type dementia which 80%) and 21.8% of patients were determined in depression. There are 34% of the association of depression with Alzheimer’s disease. Hospital results in line with world data. 10-15% of the incidence of dementia in people aged 65 and over, 80 years and 30% over 50. 4 million in the United States, 15 million around the world, and there are an estimated 500,000 dementia patient in 250-Turkey. In addition, a clinical dementia, mild cognitive impairment, which is on the table for the country’s estimated figure of 500,000-1,000,000 ages disease. However, the number of dementia patients registered and known ten thousand. These patients? Where is the mistake? What should be the responsibility of physicians working in primary health care services? What should be the responsibility of a naturopathic physician of internal medicine? Questions such as what should be the responsibility of pharmacists. Why Turkey looking at very low numbers of dementia in the elderly, among the reasons he went to go to the doctor less, and also at the forefront of cardiovascular and musculoskeletal problems, dementia, old-family-physician-pharmacist by unknown enough and ignoring the and forgetfulness is located in old age as a natural result of the adoption.
Dementia is caused by the person to serious morbidity, increased mortality, and people looking at the patient as well as the economic burden imposed due to the heavy load, and insurance systems is an important public health problem. Memory problems by patients and their relatives are often considered as a natural consequence of aging, so we overlooked the early stages. Cognitive function in elderly patients admitted for any reason, the questioning is important to capture the early stages of dementia. Dementia is a chronic brain disease, or encephalopathy, cognitive and behavioral disorders caused by a clinical entity. Dementia is a progressive degenerative brain syndromes is a result of diseases and vascular diseases. In the differential diagnosis of trauma, hypoxia and metabolic causes should be considered a chronic encephalopathy. Dementia is a decline in cognitive functioning for the definition should be based on the patient’s previous state, must have influenced everyday life as well as multiple cognitive disorders and memory space (aphasia, agnosia, apraxia, executive dysfunction) should disorder. Alzheimer’s disease with mild-to-moderate-to-severe memory impairment language, management, decision-making functions, alertness, orientation, and personality disorders, intellectual skills acquired in a progressive and fatal progressive neurodegenerative disorder characterized by loss.
Memory and cognitive functions in a variety of progressive decline in daily living activities, impairment, neuropsychiatric symptoms and behavioral disturbances. Progressive, severe morbidity and mortality, daily life is a disease that causes deterioration, behavioral symptoms in the early stage of treatment quality of life and cognitive functions in areas protected for a long time due to the early stage of the disease than the recognition, not importance. To start the active treatment in the early stage of Alzheimer’s disease recognized as true, that can cause early stage detection of reasons, can be treated with demansa dementia is recognized to the exclusion of.
The average annual cost of Alzheimer’s disease in the United States brought in $ 100 billion. When looking at these results and oftens, early diagnosis and treatment of Alzheimer’s disease and the importance of other dementia. The incidence of dementia is increasing with age, especially in the early stages of the disease, despite the fact that a disease diagnosis indicted. To MCI and dementia can be treated as early as possible in the stage of the disease to diagnose secondary, it is important to eliminate the detected and can be removed. Cure for the disease start early medication also increases the quality of life of the patient, the patient’s is relatively self enough to make coming of continuous maintenance functions requires added delays and manages, in total health spending in this direction is very important to reduce. Alzheimer’s disease increases with age and life expectancy increases, the frequency of Alzheimer’s disease is thought to increase in frequency. Incidence of Alzheimer’s disease doubles every five years. 50% to 70 percent of all cases of dementia are Alzheimer’s disease. The remaining 10-25% 5-10% of vascular dementia often there were other less frequently encountered causes. Dementia classification are shown in table 2.
Table-2: Classification of Dementia
1 Alzheimer’s disease
2 Vascular dementia
I. Multi-infarct dementia
II. Situated in a strategic infarcts
III. Multiple subcortical lacunar infarcts
IV. Binswanger’in subcortical arteriosclerotic leukoencephalopathy
V. Combination of Type 1,2 and 3
VI. Single or multiple hemorrhagic cerebral lesions
VII. subcortical dementias
VIII. Combined form of Alzheimer type dementia and vascular dementia
3 Parkinson’s disease
4 Huntington’s dementia
5 Pick’s disease
6 Frontotemporal dementia
7 Progressive multifocal leukoencephalopathy
8 Progressive supranuclear palsy
9 Depression and pseudodementia
10 Dementia with Lewy bodies
12 Normal pressure hydrocephalus
13 Subdural hematoma
Difficulty in learning and remembering the typical triad of AD, visuospasyal problems and language problems. Insight into the planning and organizational capabilities of the patient is usually not aware of these problems has lost. Sürdürebilse social relations in the early stages of the disease, the difficulty and decisions in the complex. Usually as a result of old age, current findings are considered by the relatives of the patient, diagnosis may be delayed for 1-2 years.
AH which is typical for people, time and place orientasion corruption. Difficulty remembering the words of the patient initially, loss of speech fluency breakdown and even goes back to the conversation completely. As well as other cognitive functions of speech continues the slow but steady loss. Ah can be seen in many psychiatric and behavioral disorders. With the advancement of the disease, especially agitation, hallucinations, and paranoid symptoms are monitored frequently.
Vascular dementia (VAD) in the diagnosis of dementia in a patient with clinical cerebrovascular event is placed in the presence of clinical or radiological findings. Following the findings of a cerebrovascular event demansiyal patient suddenly develops step by step. Unlike AH’den VaD’da less severe memory loss. Vascular dementia, depression in contrast to the more severe AD via slowing.
Dementia with Lewy bodies (LCD) is a classic triad of parkinsonism, cognitive impairment and visual hallucinations fluctuations. Dementia with parkinsonism is typical to begin with. Visuospasyal AH’den in the early stages of different skills, problem-solving rate decreased very significantly. All of these findings in more than half of the patients with visual hallucinations and typically will worsen with the use of neuroleptics.
Frontotemporal dementia is a change in behavior, poor personal and social judgment, perseveration, and stereotyped behaviors, lack of awareness of, planning to be at the forefront of the deterioration is a type of dementia. Occurs at a younger age. In the early stages of the disease MMSE (Mini-Mental Status Examination-MMSE) may be normal, but personality changes, speech fluency is at an early stage than AH’ına reduction. Interestingly, the memory functions may be relatively preserved.
Parkinson’s disease (PD), Huntington’s disease, HIV, and the development of cognitive impairment and dementia associated with alcoholism. PH may develop during the course of dementia by up to 30%. HIV (+) patients, 2/3 thirds dementia available, but only symptom of dementia occurrence as <10% of cases are seen. This is attributed to destruction of antiretroviral therapy consisting of the central nervous system.
…a kind of communication system. This sends messages to the outside world and the communication system, the individual commands from the brain’s normal output paths of the environment and the muscles.
According to the definition above, is perceived and interpreted by the brain as long as this type of activity may be called a system, and for that BBA electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), positron emission tomography (PET), and so on. techniques can be used, but so far have been used extensively technical studies EEG to BBA.
Judging historical perspective, “brain computer interface” is one of those who used the term first Jacques J. Vidal. Vidal, in 1973, the study analyzed the EEG signals to detect, analyze and locate them in a certain pre-defined patterns in a complex computer system developed to review the motion commands. “Dependent BBA is defined as” the ability to control the system based on the user’s eye movements (BBA dependent described below).
What makes it possible to ICA? As can be seen from the above example and the definition, ICA, enabling them to record the signals produced by the brain to retain our sense of pattern analysis and classification is needed. Recording signals from the brain and what they mean? The short answer is: two types of communication takes place in the brain, electrical and chemical. Both types of communication in the “visible” effects and some of the devices is possible to identify them. BBA is important for the brain’s electrical communication. Triggering action potentials in the brain and can be detected on the surface of their axons communicated in the skull leads to physical activity.
BBA is the most widely used mode of communication in the field of electrical communication some space for it to be there. Without EEG practical, working hard to build a BCI system.
Electroencephalography (EEG) for the first time the term was used by Berger. Berger, can be determined, and can be read brain waves showed that the surface of the human skull.
According to Vidal skull just below the skull surface is the main source of electrical potentials that make up the outer shell of the brain’s electrical activity in the cerebral cortex. The cerebral cortex, nerve cells (neurons) in a thin layer of gray matter contains. Some of these cells (pyramidal cells), and laterally extends towards the surface of the brain that has a dendrite apik extracting. As a result, a thin “white matter” consists of the surface, where the thin heavily intertwined other neighboring dendrites and dendritic extensions establish a connection. The center of the dendrites of neurons that transmit electrical field electrolytic connection tools. Electrical signal to the center of the cell, depolarizing the cell membrane and thus triggers cell excretion intercellular signaling a kind of re-fitting the other moves out of the axon. Apical dendrites of pyramidal cells, and the cell in the center of the observed surface potentials (body, somma) is produced. This corresponds to the potential inside the cell polarization and depolarization (electrical potential changes in the postsynaptic (after synapses) between neurons, synapses, because it is considered as the interaction takes place). Intercellular space vertically, the electrical currents of the cells is also a kind of dendrites deep to provide feedback connection are also envisioned. Deep regions recorded positive change in the surface of a depolarization (higher excitability) corresponds to (and of course vice versa). correspond to a region of depolarization (greater excitability) in the deeper regions and vice versa.
Table 3 shows how the pyramidal cells lie on the upper part of the brain and EEG signal detection and for recording are located close to the electrodes is shown schematically.
There are two types BBA, dependent and independent. This distinction is related to the dependence on ways out of the brain. The differences between the two types described below.
Dependent on the brain’s normal output channels use a BCI system. Therefore, one way or another this kind of BBA requires a fully functional nervous system. To give an example of a popular BBA, a large portion of the body of a patient with a paralyzed individual letters will be shown on the screen. Select the desired letter appears on the display if you concentrate on the patient looks at the letter. This situation leads to visually triggered potential (visual evoked potentials – GTP) and can be detected by EEG equipment. The reason is that it is possible to concentrate the patient looks at a certain time, look at the letter that the state is higher than the other letters creates a GTP.
Although helpful, though in some cases such BBA systems (e.g. user-friendliness and smooth learning curve), the system relies on
the presence of the nervous system is a very undamaged. Something that is being used in the production of the EEG signal eye muscles and cranial nerve cells that control them.
BCI system does not require a solid peripheral nervous system independent. Such a BBA only the user “trends” based on what.
Going back to the example above, select the letter, the letter you want to do is to think independently of the user’s ICA is used. In this mechanism, the movement of the eye, there is nothing about or control. In this case detected by the EEG of P300 (P300 described below).
BCI system can be divided into five sub-system is a modern:
• Signal acquisition
• Signal processing: feature extraction
• Signal processing: conversion algorithm
• Output device
• Management Protocol
Tablo-3; seems to be essential components of a BCI system
Signal acquisition is the first step in the process of a BBA. To record the signals from the brain, the most widely used method to detect and EEGs. EEG is a non-intrusive method, but also communicate with the exception of electrical communication takes place in the brain functional magnetic resonance imaging (functional magnetic resonance imaging – fMRI) will be consulted as to the methods. In a study in 2004, the use of fMRI to detect brain signals Weiskopf’un mentioned.
Another method used to record brain signals intrusive techniques. Kennedy, in 2004 a study on the surface of the brain and the brain surface of the implant a neural signals are then detected and used to control a computer cursor discloses BBA system.
Signal processing: feature extraction
After recording electrical signals using EEG to identify the features in them, must be removed. This process can be considered as a preprocessing before the pattern recognition and classification.
In this process, the raw data of the digital signal is received and are summarized in some respects. Spatial filtering, spectral analysis and measurement of the severity of the voltage of the techniques used to extract features.
Signal processing: conversion algorithm
Some features of the digital signal to the brain summarization data storage, these scanning and recognizing the patterns in the information required. BCI system which commands need to be performed only in this way “understand”.
Characteristics of the collected data will be used to analyze the various algorithms. There are two broad categories: linear equations based on non-linear statistical analysis and artificial neural networks and other pattern classifiers.
These algorithms must be adaptable and resistant to errors in the BBA’s because every time the “same thing” While considering the various deviations from brain signals, will surely be minor fluctuations. The adaptability and flexibility of the algorithm “learn” in terms of importance. I also think as a speech or image processing application. These applications are trained to commit the data, and often commit some respects, it is user-specific characteristics of the data. Beyond that, the flexibility of the algorithm, and the ability to learn another situation in which there are also important: People do not stay the same in the process. A wisp of metabolic changes, diseases, and even the time of day that seasonal changes in one’s body and thus the functioning of the brain changes in some respects. The brain of a mammal, but not during the day, eg. a certain chemical in the morning to take a certain dose of a rat fell asleep in the afternoon the same dose of the same chemical, stay up all night to see if you might be surprised. That pattern classification and conversion algorithms to overcome these changes can be seen as variations on the same theme have to come to them to be tolerant.
The third level is a highly sophisticated information processing algorithms require adaptability. BCI system at this stage adaptation of the brain that have adapted to the system “to realize” requires. What does this mean? Learning how to use the system to change and BBA BBA’s brain, trying to be adapted to suit the work in harmony with the brain gives feedback to the brain properly, the user is given the award with the right timing, the machine consists of a strong connection between the user.
BBA is a modern system, but often these devices are computers that can be output to any device or computer controlled robots. Research and experiments to provide feedback to the user, and it is usually on a computer monitor, cursors, icons and characters used in elections.
The behavior of the system in general, and the use of the operating protocol is a set of rules that determine. What kind of system is a communication protocol to use, what kind of signals from the brain to analyze the interaction between the user and the system determines the way.
BBA Expert researchers and technicians are ready to help the patient in a laboratory environment, or whether the user of this protocol may not be important or very detailed. But if the real-life environment of a BCI system is to be used by the patient, and the patient himself alone device on or off, you have to give the command of the details of the protocol extreme importance.
A microcontroller (MCU, and also referred to as μC), a micro-processor, CPU, memory, and input – output, crystal oscillator, timers (timers), serial and analog inputs and outputs, programmable memory (NOR Flash, OTP-ROM) components, such as a single produced on an integrated circuit state.
Although limited amount, enough memory units, and input – output terminals can work alone, as they have with the hardware circuitry may contact other electronic forms, perform the functions required by the application. Hosting of integrated circuits, such as analog-to-digital converter with them all kinds of sensors can be used in data collection and processing. Allows applications to be preferred to be buried in a small and cost-effective.
Also listed below are four main advantages compared to microprocessors microcontrollers with ordinary electronic industry nowadays have quite a large range of applications:
• Very small size,
• Very low power consumption,
• Low cost,
• High performance.
For example, the simple electronic watches automatic washing machines, robots cameras, LCD monitors, biomedical devices, and industrial automation applications, electronic tickets until they are used in many electronic applications microcontrollers.
The hippocampus is required for replacement of electronic units, the chip is a combination of the two. Brain-computer interface chip micro-controller units and merged with the ability to serve the purpose of the project will have reached a chip.
Placing the upper side of the hippocampus chip with open brain surgery. Each micro-controller receives the electromagnetic wave and keep the other related to the brain lobes of the brain-computer interface will communicate with. To do this, the brain computer interface by double output will transfer through the right and left hemispheres conductive element. Is no longer going to be a two-way one-way information. In the way of information to the hippocampus, the brain computer interface arranged to login forgotten prevent that information from. To avoid conflict with the micro-controller will be activated. Operation of the project will be
displayed in the slide show.
The aim of this project will lead to the treatment of dementia in the front know. Because no information to the hippocampus and / or do not have the idea that will be prevented. At all other dementias, including Alzheimer’s patients in science as a method of input will make a new treatment.
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