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Posterior Cortical Atrophy
Posterior cortical atrophy (PCA), also called Benson's syndrome, is a rare form of dementia which is considered a visual variant or an atypical variant of Alzheimer's disease (AD). The disease causes atrophy of the posterior part of the cerebral cortex, resulting in the progressive disruption of complex visual processing. PCA was first described by D. Frank Benson in 1988. PCA usually affects people at an earlier age than typical cases of Alzheimer's disease, with initial symptoms often experienced in people in their mid-fifties or early sixties. This was the case with writer Terry Pratchett (1948–2015), who went public in 2007 about being diagnosed with PCA. In rare cases, PCA can be caused by dementia with Lewy bodies and Creutzfeldt–Jakob disease. Symptoms The main symptom resulting from posterior cortical atrophy is a decrease in visuospatial and visuoperceptual capabilities, since the area of atrophy involves the occipital lobe responsible for visual processing. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dementia
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 activities of daily living, everyday activities. This typically involves problems with memory, thinking, behavior, and motor control. Aside from memory impairment and a thought disorder, 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 (measurement), 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, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Agnosia
Visual agnosia is an impairment in recognition of visually presented objects. It is not due to a deficit in vision (acuity, visual field, and scanning), language, memory, or intellect. While cortical blindness results from lesions to primary visual cortex, visual agnosia is often due to damage to more anterior cortex such as the posterior occipital and/or temporal lobe(s) in the brain. /sup> There are two types of visual agnosia, apperceptive and associative. Recognition of visual objects occurs at two levels. At an apperceptive level, the features of the visual information from the retina are put together to form a perceptual representation of an object. At an associative level, the meaning of an object is attached to the perceptual representation and the object is identified. If a person is unable to recognize objects because they cannot perceive correct forms of the objects, although their knowledge of the objects is intact (i.e. they do not have anomia), they have appercepti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grey Matter
Grey matter, or gray matter in American English, is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil ( dendrites and unmyelinated axons), glial cells ( astrocytes and oligodendrocytes), synapses, and capillaries. Grey matter is distinguished from white matter in that it contains numerous cell bodies and relatively few myelinated axons, while white matter contains relatively few cell bodies and is composed chiefly of long-range myelinated axons. The colour difference arises mainly from the whiteness of myelin. In living tissue, grey matter actually has a very light grey colour with yellowish or pinkish hues, which come from capillary blood vessels and neuronal cell bodies. Structure Grey matter refers to unmyelinated neurons and other cells of the central nervous system. It is present in the brain, brainstem and cerebellum, and present throughout the spinal cord. Grey matter is distributed at the surface of the cerebral hemisp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Senile Plaques
Amyloid plaques (also known as neuritic plaques, amyloid beta plaques or senile plaques) are extracellular deposits of amyloid beta (Aβ) protein that present mainly in the grey matter of the brain. Degeneration (medical), Degenerative neuronal elements and an abundance of microglia and astrocytes can be associated with amyloid plaques. Some plaques occur in the brain as a result of Aging brain, aging, but large numbers of plaques and neurofibrillary tangles are characteristic features of Alzheimer's disease. The plaques are highly variable in shape and size; in tissue sections immunohistochemistry, immunostained for Aβ, they comprise a log-normal size distribution curve, with an average plaque area of 400–450 square micrometers (μm2). The smallest plaques (less than 200 μm2), which often consist of diffuse deposits of Aβ, are particularly numerous. Plaques form when Aβ misfolds and aggregates into oligomers and longer polymers, the latter of which are characteristic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurofibrillary Tangle
Neurofibrillary tangles (NFTs) are intracellular aggregates of hyperphosphorylated tau protein that are most commonly known as a primary Biomarker (medicine), biomarker of Alzheimer's disease. Their presence is also found in numerous other diseases known as Tauopathy, tauopathies. Little is known about their exact relationship to the different pathologies. Formation Neurofibrillary tangles are formed by phosphorylation, hyperphosphorylation of a microtubule-associated protein known as tau (protein), tau, causing it to aggregate, or group, in an insoluble form. (These aggregations of hyperphosphorylated tau protein are also referred to as PHF, or "paired helical filaments"). The precise mechanism of tangle formation is not completely understood, though it is typically recognized that tangles are a primary causative factor in neurodegenerative disease. Cytoskeletal changes Three different maturation states of NFT have been defined using anti-tau and anti-ubiquitin immunostaining. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depression (mood)
Depression is a mental state of low Mood (psychology), mood and aversion to activity. It affects about 3.5% of the global population, or about 280 million people worldwide, as of 2020. Depression affects a person's thoughts, behavior, feelings, and subjective well-being, sense of well-being. The pleasure or joy that a person gets from certain experiences is reduced, and the afflicted person often experiences a loss of motivation or interest in those activities. People with depression may experience sadness, feelings of dejection or hopelessness, difficulty in thinking and concentration, or a significant change in appetite or time spent sleeping; Suicidal ideation, suicidal thoughts can also be experienced. Depression can have multiple, sometimes overlapping, origins. Depression can be a symptom of some mood disorders, some of which are also commonly called ''depression'', such as major depressive disorder, bipolar disorder and dysthymia. Additionally, depression can be a norm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anxiety
Anxiety is an emotion characterised by an unpleasant state of inner wikt:turmoil, turmoil and includes feelings of dread over Anticipation, anticipated events. Anxiety is different from fear in that fear is defined as the emotional response to a present threat, whereas anxiety is the anticipation of a future one. It is often accompanied by nervous behavior such as pacing back and forth, Somatic anxiety, somatic complaints, and Rumination (psychology), rumination. Anxiety is a feeling of uneasiness and worry, usually generalized and unfocused as an overreaction to a situation that is only subjectively seen as menacing. It is often accompanied by muscular tension, restlessness, Fatigue (medical), fatigue, inability to catch one's breath, tightness in the abdominal region, nausea, and problems in concentration. Anxiety is closely related to fear, which is a response to a real or perceived immediate threat (fight-or-flight response); anxiety involves the expectation of a future t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemispatial Neglect
Hemispatial neglect is a neuropsychological condition in which, after damage to one hemisphere of the brain (e.g. after a stroke), a deficit in attention and awareness towards the side of space opposite brain damage (contralesional space) is observed. It is defined by the inability of a person to process and perceive stimuli towards the contralesional side of the body or environment. Hemispatial neglect is very commonly contralateral to the damaged hemisphere, but instances of ipsilesional neglect (on the same side as the lesion) have been reported. Presentation Hemispatial neglect results most commonly from strokes and brain unilateral injury to the right cerebral hemisphere, with rates in the critical stage of up to 80% causing visual neglect of the left-hand side of space. Neglect is often produced by massive strokes in the middle cerebral artery region and is variegated, so that most sufferers do not exhibit all of the syndrome's traits. Right-sided spatial neglect is rare ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurodegeneration
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 cell death, death. Neurodegenerative diseases include amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease, Alzheimer's disease, Huntington's disease, multiple system atrophy, Tauopathy, 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 su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parietal Lobe
The parietal lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus. The parietal lobe integrates sensory information among various sensory modality, modalities, including spatial sense and navigation (proprioception), the main sensory receptive area for the sense of touch in the somatosensory cortex which is just posterior to the central sulcus in the postcentral gyrus, and the two-streams hypothesis#Dorsal stream, dorsal stream of the visual system. The major sensory inputs from the skin (mechanoreceptor, touch, thermoreceptor, temperature, and nociceptor, pain receptors), relay through the thalamus to the parietal lobe. Several areas of the parietal lobe are important in language processing in the brain, language processing. The somatosensory cortex can be illustrated as a distorted figure – the cortical homunculus (Latin: "li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Lobe
The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobe is involved in processing sensory input into derived meanings for the appropriate retention of visual memory, language comprehension, and emotion association. ''Temporal'' refers to the head's temples. Structure The temporal lobe consists of structures that are vital for declarative or long-term memory. Declarative (denotative) or explicit memory is conscious memory divided into semantic memory (facts) and episodic memory (events). The medial temporal lobe structures are critical for long-term memory, and include the hippocampal formation, perirhinal cortex, parahippocampal, and entorhinal neocortical regions. The hippocampus is critical for memory formation, and the surrounding medial temporal cortex is currently theorized to be critical f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
