Alzheimer's disease in the context of Intravital microscopy

In philosophy, the self is an individual's own being, knowledge, and values, and the relationship between these attributes.

The first-person perspective distinguishes selfhood from personal identity. Whereas "identity" is (literally) sameness and may involve categorization and labeling,selfhood implies a first-person perspective and suggests potential uniqueness. Conversely, "person" is used as a third-person reference. Personal identity can be impaired in late-stage Alzheimer's disease and in other neurodegenerative diseases. Finally, the self is distinguishable from "others". Including the distinction between sameness and otherness, the self versus other is a research topic in contemporary philosophy and contemporary phenomenology (see also psychological phenomenology), psychology, psychiatry, neurology, and neuroscience.

Neurology (from Greek: νεῦρον (neûron), "string, nerve" and the suffix -logia, "study of") is the branch of medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the nervous system, which comprises the brain, the spinal cord and the peripheral nerves. Neurological practice relies heavily on the field of neuroscience, the scientific study of the nervous system, using various techniques of neurotherapy.

A neurologist is a physician specializing in neurology and trained to investigate, diagnose and treat neurological disorders. Neurologists diagnose and treat myriad neurologic conditions, including stroke, epilepsy, movement disorders such as Parkinson's disease, brain infections, autoimmune neurologic disorders such as multiple sclerosis, sleep disorders, brain injury, headache disorders like migraine, tumors of the brain and dementias such as Alzheimer's disease. Neurologists may also have roles in clinical research, clinical trials, and basic or translational research. Neurology is a nonsurgical specialty, its corresponding surgical specialty is neurosurgery.

Abdominal obesity, also known as central obesity and truncal obesity, is the human condition of an excessive concentration of visceral fat around the stomach and abdomen to such an extent that it is likely to harm its bearer's health. Abdominal obesity has been strongly linked to cardiovascular disease, Alzheimer's disease, and other metabolic and vascular diseases.

Visceral fat, central abdominal fat, and waist circumference show a strong association with type 2 diabetes.

A neurodegenerative disease is caused by the progressive loss of neurons, in the process known as neurodegeneration. Neuronal damage may also ultimately result in their death. Neurodegenerative diseases include amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease, Alzheimer's disease, Huntington's disease, multiple system atrophy, tauopathies, and prion diseases. Neurodegeneration can be found in the brain at many different levels of neuronal circuitry, ranging from molecular to systemic. Because there is no known way to reverse the progressive degeneration of neurons, these diseases are considered to be incurable; however research has shown that the two major contributing factors to neurodegeneration are oxidative stress and inflammation. Biomedical research has revealed many similarities between these diseases at the subcellular level, including atypical protein assemblies (like proteinopathy) and induced cell death. These similarities suggest that therapeutic advances against one neurodegenerative disease might ameliorate other diseases as well.

Within neurodegenerative diseases, it is estimated that 55 million people worldwide had dementia in 2019, and that by 2050 this figure will increase to 139 million people.

Awareness ribbons are symbols meant to show support or raise consciousness for a cause. Different colors and patterns are associated with different issues. Awareness ribbons can be worn on clothing like pins, they can be appear on bumper stickers in vehicles, or they can be on arm wristbands, among many other ways. The ribbon is a symbol of awareness and support.

Of the uses of ribbons to draw awareness to health issues, perhaps the best-known is the pink ribbon for support of those with breast cancer. Other health and social concerns which have adopted colored ribbons include Alzheimer's disease and pancreatic cancer (purple), HIV/AIDS (red), mental health and mental illness (green), suicide prevention and for brain disorder or disability (silver).

Human behaviour genetics is an interdisciplinary subfield of behaviour genetics that studies the role of genetic and environmental influences on human behaviour. Classically, human behavioural geneticists have studied the inheritance of behavioural traits. The field was originally focused on determining the importance of genetic influences on human behaviour (for e.g., do genes regulate human behavioural attributes). It has evolved to address more complex questions such as: how important are genetic and/or environmental influences on various human behavioural traits; to what extent do the same genetic and/or environmental influences impact the overlap between human behavioural traits; how do genetic and/or environmental influences on behaviour change across development; and what environmental factors moderate the importance of genetic effects on human behaviour (gene-environment interaction). The field is interdisciplinary, and draws from genetics, psychology, and statistics. Most recently, the field has moved into the area of statistical genetics, with many behavioural geneticists also involved in efforts to identify the specific genes involved in human behaviour, and to understand how the effects associated with these genes changes across time, and in conjunction with the environment.

Traditionally, the human behavioural genetics were a psychology and phenotype based studies including intelligence, personality and grasping ability. During the years, the study developed beyond the classical traits of human behaviour and included more genetically associated traits like genetic disorders (such as fragile X syndrome, Alzheimer's disease and obesity). The traditional methods of behavioural-genetic analysis provide a quantitative evaluation of genetic and non-genetic influences on human behaviour. The family, twin and adoption studies marks the huge contribution for laying down the foundation for current molecular genetic studies to study human behaviour.

Dementia is a syndrome associated with many neurodegenerative diseases, characterized by a general decline in cognitive abilities that affects a person's ability to perform everyday activities. This typically involves problems with memory, thinking, behavior, and motor control. Aside from memory impairment and a disruption in thought patterns, the most common symptoms of dementia include emotional problems, difficulties with language, and decreased motivation. The symptoms may be described as occurring in a continuum over several stages. Dementia is a life-limiting condition, having a significant effect on the individual, their caregivers, and their social relationships in general. A diagnosis of dementia requires the observation of a change from a person's usual mental functioning and a greater cognitive decline than might be caused by the normal aging process.

Several diseases and injuries to the brain, such as a stroke, can give rise to dementia. However, the most common cause is Alzheimer's disease, a neurodegenerative disorder. Dementia is a neurocognitive disorder with varying degrees of severity (mild to major) and many forms or subtypes. Dementia is an acquired brain syndrome, marked by a decline in cognitive function, and is contrasted with neurodevelopmental disorders. It has also been described as a spectrum of disorders with subtypes of dementia based on which known disorder caused its development, such as Parkinson's disease for Parkinson's disease dementia, Huntington's disease for Huntington's disease dementia, vascular disease for vascular dementia, HIV infection causing HIV dementia, frontotemporal lobar degeneration for frontotemporal dementia, Lewy body disease for dementia with Lewy bodies, and prion diseases. Subtypes of neurodegenerative dementias may also be based on the underlying pathology of misfolded proteins, such as synucleinopathies and tauopathies. The coexistence of more than one type of dementia is known as mixed dementia.

Degenerative disease is the result of a continuous process based on degenerative cell changes, affecting tissues or organs, which will increasingly deteriorate over time.

In neurodegenerative diseases, cells of the central nervous system stop working or die via neurodegeneration. An example of this is Alzheimer's disease. The other two common groups of degenerative diseases are those that affect circulatory system (e.g. coronary artery disease) and neoplastic diseases (e.g. cancers).

A non-communicable disease (NCD) is a disease that is not transmissible directly from one person to another. NCDs include Parkinson's disease, autoimmune diseases, strokes, heart diseases, cancers, diabetes, chronic kidney disease, osteoarthritis, osteoporosis, Alzheimer's disease, cataracts, and others. NCDs may be chronic or acute. Most are non-infectious, although there are some non-communicable infectious diseases, such as parasitic diseases in which the parasite's life cycle does not include direct host-to-host transmission.

The four main NCDs that are the leading causes of death globally are cardiovascular disease, cancer, chronic respiratory diseases, and diabetes. NCDs account for seven out of the ten leading causes of death worldwide. Figures given for 2019 are 41 million deaths due to NCDs worldwide. Of these 17.9 million were due to cardiovascular disease; 9.3 million due to cancer; 4.1 million to chronic respiratory diseases, and 2.0 million to diabetes. Over 80% of the deaths from these four groups were premature, not reaching the age of 70.

Lifestyle diseases can be defined as the diseases linked to the manner in which a person lives their life. These diseases are non-communicable, and can be caused by lack of physical activity, unhealthy eating, alcohol, substance use disorders and smoking tobacco, which can lead to heart disease, stroke, obesity, type II diabetes and lung cancer. The diseases that appear to increase in frequency as countries become more industrialized and people live longer include Alzheimer's disease, arthritis, atherosclerosis, asthma, cancer, chronic liver disease or cirrhosis, chronic obstructive pulmonary disease, colitis, irritable bowel syndrome, type 2 diabetes, heart disease, hypertension, metabolic syndrome, chronic kidney failure, osteoporosis, PCOD, stroke, depression, obesity and vascular dementia.

Concerns were raised in 2011 that lifestyle diseases could soon have an impact on the workforce and the cost of health care. Treating these non-communicable diseases can be expensive. It can be critical for the patient's health to receive primary prevention and identify early symptoms of these non-communicable diseases. These lifestyle diseases are expected to increase throughout the years if people do not improve their lifestyle choices.

Olfactory memory refers to the recollection of odors. Studies have found various characteristics of common memories of odor memory including persistence and high resistance to interference. Explicit memory is typically the form focused on in the studies of olfactory memory, though implicit forms of memory certainly supply distinct contributions to the understanding of odors and memories of them. Research has demonstrated that the changes to the olfactory bulb and main olfactory system following birth are extremely important and influential for maternal behavior. Mammalian olfactory cues play an important role in the coordination of the mother infant bond, and the following normal development of the offspring. Maternal breast odors are individually distinctive, and provide a basis for recognition of the mother by her offspring.

Throughout evolutionary history, olfaction has served various purposes related to the survival of the species, such as the development of communication. Even in humans and other animals today, these survival and communication aspects are still functioning. There is also evidence suggesting that there are deficits in olfactory memory in individuals with brain degenerative diseases such as Parkinson's disease, Alzheimer's disease and dementia. These individuals lose the ability to distinguish smells as their disease worsens. There is also research showing that deficits in olfactory memory can act as a base in assessing certain types of mental disorders such as depression as each mental disorder has its own distinct pattern of olfactory deficits.

The hippocampus (pl.: hippocampi; via Latin from Greek ἱππόκαμπος, 'seahorse'), also hippocampus proper, is a major component of the brain of humans and many other vertebrates. In the human brain the hippocampus, the dentate gyrus, and the subiculum are components of the hippocampal formation located in the limbic system. The hippocampus plays important roles in the consolidation of information from short-term memory to long-term memory, and in spatial memory that enables navigation. In humans and other primates the hippocampus is located in the archicortex, one of the three regions of allocortex, in each hemisphere with direct neural projections to, and reciprocal indirect projections from the neocortex. The hippocampus, as the medial pallium, is a structure found in all vertebrates.

In Alzheimer's disease (and other forms of dementia), the hippocampus is one of the first regions of the brain to be damaged; short-term memory loss and disorientation are included among the early symptoms. Damage to the hippocampus can also result from oxygen starvation (hypoxia), encephalitis, or medial temporal lobe epilepsy. People with extensive, bilateral hippocampal damage may experience anterograde amnesia: the inability to form and retain new memories.

Processed meat is considered to be any meat that has been modified in order to either improve its taste or to extend its shelf life. Methods of meat processing include salting, curing, fermentation, smoking, and the addition of chemical preservatives. Processed meat is frequently made from pork or beef, but also poultry and others. It can contain meat by-products such as blood. Processed meat products include bacon, ham, sausages, salami, corned beef, jerky, hot dogs, lunch meat, canned meat, chicken nuggets, and meat-based sauces. Meat processing includes all the processes that change fresh meat, with the exception of simple mechanical processes such as cutting, grinding or mixing.

Meat processing began as soon as people realized that cooking and salting helps to preserve fresh meat. It is not known when this took place; however, the process of salting and sun-drying was recorded in Ancient Egypt, while using ice and snow is credited to early Romans, and canning was developed by Nicolas Appert who in 1810 received a prize for his invention from the French government. Medical health organizations advise people to limit processed meat consumption as it increases risk of some forms of cancer, cardiovascular disease, and Alzheimer's disease.

The Indiana University School of Medicine (IUSM) is a major, multi-campus medical school located throughout the U.S. state of Indiana and is both the undergraduate and graduate medical school of Indiana University. There are nine campuses throughout the state; the principal research, educational, and medical center is located on the campus of Indiana University Indianapolis. With 1,448 MD students, 191 PhD students, and 1,438 residents and fellows in the 2024–25 academic year, IUSM is the largest medical school in the United States. The school offers many joint degree programs including an MD/PhD Medical Scientist Training Program. It has partnerships with Purdue University's Weldon School of Biomedical Engineering, other Indiana University system schools, and various in-state external institutions. It is the medical school with the largest number of graduates licensed in the United States per a 2018 Federation of State Medical Boards survey with 11,828 licensed physicians.

The school has pioneered research in multiple specialties, including oncology, immunology, substance use, neuroscience, and endocrinology. Research discoveries include a curative therapy for testicular cancer, the development of echocardiography, the identification of several genes linked to Alzheimer's disease, and the creation of inner ear sensory cells from pluripotent stem cells.

In excitotoxicity, nerve cells suffer damage or death when the levels of otherwise necessary and safe neurotransmitters such as glutamate become pathologically high, resulting in excessive stimulation of receptors. For example, when glutamate receptors such as NMDA receptors or AMPA receptors encounter excessive levels of the excitatory neurotransmitter, glutamate, significant neuronal damage might ensue. Different mechanisms might lead to increased extracellular glutamate concentrations, e.g. reduced uptake by glutamate transporters (EAATs), synaptic hyperactivity, or abnormal release from different neural cell types. Excess glutamate allows high levels of calcium ions (Ca) to enter the cell. Ca influx into cells activates a number of enzymes, including phospholipases, endonucleases, and proteases such as calpain. These enzymes go on to damage cell structures such as components of the cytoskeleton, membrane, and DNA. In evolved, complex adaptive systems such as biological life it must be understood that mechanisms are rarely, if ever, simplistically direct. For example, NMDA, in subtoxic amounts, can block glutamate toxicity and induce neuronal survival. In addition to abnormally high neurotransmitter concentrations, also elevation of the extracellular potassium concentration, acidification and other mechanisms may contribute to excitotoxicity.

Excitotoxicity may be involved in cancers, spinal cord injury, stroke, traumatic brain injury, hearing loss (through noise overexposure or ototoxicity), and in neurodegenerative diseases of the central nervous system such as multiple sclerosis, Alzheimer's disease, amyotrophic lateral sclerosis (ALS), Parkinson's disease, alcoholism, alcohol withdrawal or hyperammonemia and especially over-rapid benzodiazepine withdrawal, and also Huntington's disease. Other common conditions that cause excessive glutamate concentrations around neurons are hypoglycemia. Blood sugars are the primary energy source for glutamate removal from inter-synaptic spaces at the NMDA and AMPA receptor site. Persons in excitotoxic shock must never fall into hypoglycemia. Patients should be given 5% glucose (dextrose) IV drip during excitotoxic shock to avoid a dangerous build up of glutamate. When 5% glucose (dextrose) IV drip is not available high levels of fructose are given orally. Treatment is administered during the acute stages of excitotoxic shock along with glutamate receptor antagonists. Dehydration should be avoided as this also contributes to the concentrations of glutamate in the inter-synaptic cleft and "status epilepticus can also be triggered by a build up of glutamate around inter-synaptic neurons."

Nasal sprays are used to deliver medications locally in the nasal cavities or systemically. They are used locally for conditions such as nasal congestion and allergic rhinitis. In some situations, the nasal delivery route is preferred for systemic therapy because it provides an agreeable alternative to injection or pills. Substances can be assimilated extremely quickly and directly through the nose. Many pharmaceutical drugs exist as nasal sprays for systemic administration (e.g. sedative-analgesics, treatments for migraine, osteoporosis and nausea). Other applications include hormone replacement therapy, treatment of Alzheimer's disease and Parkinson's disease. Nasal sprays are seen as a more efficient way of transporting drugs with potential use in crossing the blood–brain barrier.