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Simultagnosia
Simultanagnosia (or simultagnosia) is a rare neurological disorder characterized by the inability of an individual to visually perceive more than a single object at a time. This type of visual attention problem is one of three major components (the others being optic ataxia and optic apraxia) of Bálint's syndrome, an uncommon and incompletely understood variety of severe neuropsychological impairments involving space representation ( visuospatial processing). The term "simultanagnosia" was first coined in 1924 by Wolpert to describe a condition where the affected individual could see individual details of a complex scene but failed to grasp the overall meaning of the image. Simultanagnosia can be divided into two different categories: dorsal and ventral. Ventral occipito- temporal lesions cause a mild form of the disorder, while dorsal occipito- parietal lesions cause a more severe form of the disorder. Description Patients with simultanagnosia, a component of Bálint's syn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agnosia
Agnosia is a neurological disorder characterized by an inability to process sensory information. Often there is a loss of ability to recognize objects, persons, sounds, shapes, or smells while the specific sense is neither defective nor is there any significant memory loss. It is usually associated with brain injury or neurological illness, particularly after damage to the occipitotemporal border, which is part of the ventral stream. Agnosia affects only a single modality, such as vision or hearing. More recently, a top-down interruption is considered to cause the disturbance of handling perceptual information. Types Visual agnosia Visual agnosia is a broad category that refers to a deficiency in the ability to recognize visual objects. Visual agnosia can be further subdivided into two different subtypes: apperceptive visual agnosia and associative visual agnosia. Individuals with apperceptive visual agnosia display the ability to see contours and outlines w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurological Disorder
Neurological disorders represent a complex array of medical conditions that fundamentally disrupt the functioning of the nervous system. These disorders affect the brain, spinal cord, and nerve networks, presenting unique diagnosis, treatment, and patient care challenges. At their core, they represent disruptions to the intricate communication systems within the nervous system, stemming from genetic predispositions, environmental factors, infections, structural abnormalities, or degenerative processes. The impact of neurological disorders is profound and far-reaching. Conditions like epilepsy create recurring seizures through abnormal electrical brain activity, while multiple sclerosis damages the protective myelin covering of nerve fibers, interrupting communication between the brain and body. Parkinson's disease progressively affects movement through the loss of dopamine-producing nerve cells, and strokes can cause immediate and potentially permanent neurological damage by inter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stroke
Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemorrhagic, due to bleeding. Both cause parts of the brain to stop functioning properly. Signs and symptoms of stroke may include an hemiplegia, inability to move or feel on one side of the body, receptive aphasia, problems understanding or expressive aphasia, speaking, dizziness, or homonymous hemianopsia, loss of vision to one side. Signs and symptoms often appear soon after the stroke has occurred. If symptoms last less than 24 hours, the stroke is a transient ischemic attack (TIA), also called a mini-stroke. subarachnoid hemorrhage, Hemorrhagic stroke may also be associated with a thunderclap headache, severe headache. The symptoms of stroke can be permanent. Long-term complications may include pneumonia and Urinary incontinence, loss of b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feature Integration Theory
Feature integration theory is a theory of attention developed in 1980 by Anne Treisman and Garry Gelade that suggests that when perceiving a stimulus, features are "registered early, automatically, and in parallel, while objects are identified separately" and at a later stage in processing. The theory has been one of the most influential psychological models of human visual attention Attention or focus, is the concentration of awareness on some phenomenon to the exclusion of other stimuli. It is the selective concentration on discrete information, either subjectively or objectively. William James (1890) wrote that "Atte .... Stages According to Treisman, the first stage of the feature integration theory is the preattentive stage. During this stage, different parts of the brain automatically gather information about basic features (colors, shape, movement) that are found in the visual field. The idea that features are automatically separated appears counterintuitive. Howev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Percept
Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous system, which in turn result from physical or chemical stimulation of the sensory system.Goldstein (2009) pp. 5–7 Vision involves light striking the retina of the eye; smell is mediated by odor molecules; and hearing involves pressure waves. Perception is not only the passive receipt of these signals, but it is also shaped by the recipient's learning, memory, expectation, and attention. Gregory, Richard. "Perception" in Gregory, Zangwill (1987) pp. 598–601. Sensory input is a process that transforms this low-level information to higher-level information (e.g., extracts shapes for object recognition). The following process connects a person's concepts and expectations (or knowledge) with restorative and selective mechanisms, suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ataxia
Ataxia (from Greek α- negative prefix+ -τάξις rder= "lack of order") is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements, that indicates dysfunction of parts of the nervous system that coordinate movement, such as the cerebellum. These nervous system dysfunctions occur in several different patterns, with different results and different possible causes. Ataxia can be limited to one side of the body, which is referred to as hemiataxia. Friedreich's ataxia has gait abnormality as the most commonly presented symptom. Dystaxia is a mild degree of ataxia. Types Cerebellar The term cerebellar ataxia is used to indicate ataxia due to dysfunction of the cerebellum. The cerebellum is responsible for integrating a significant amount of neural information that is used to coordinate smoothly ongoing movements and to participate in motor planning. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apraxia
Apraxia is a motor disorder caused by damage to the brain (specifically the posterior parietal cortex or corpus callosum), which causes difficulty with motor planning to perform tasks or movements. The nature of the damage determines the disorder's severity, and the absence of sensory loss or paralysis helps to explain the level of difficulty. Children may be born with apraxia; its cause is unknown, and symptoms are usually noticed in the early stages of development. Apraxia occurring later in life, known as ''acquired apraxia'', is typically caused by traumatic brain injury, stroke, dementia, Alzheimer's disease, brain tumor, or other neurodegenerative disorders. The multiple types of apraxia are categorized by the specific ability and/or body part affected. The term "apraxia" comes . Types The several types of apraxia include: * Apraxia of speech (AOS) is having difficulty planning and coordinating the movements necessary for speech (e.g. potato=totapo, topato).Heilma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Neuroscience
Visual neuroscience is a branch of neuroscience that focuses on the visual system of the human body, mainly located in the brain's visual cortex. The main goal of visual neuroscience is to understand how neural activity results in visual perception, as well as behaviors dependent on vision. In the past, visual neuroscience has focused primarily on how the brain (and in particular the visual cortex) responds to light rays projected from static images and onto the retina. While this provides a reasonable explanation for the visual perception of a static image, it does not provide an accurate explanation for how we perceive the world as it really is, an ever-changing, and ever-moving 3-D environment. The topics summarized below are representative of this area, but far from exhaustive. To be less topic specific, one can see this textbook for the computational link between neural activities and visual perception and behavior: "Understanding vision: theory, models, and data" , publishe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rezső Bálint (physician)
Rezső Bálint (October 22, 1874 – May 23, 1929) was a Hungarian neurologist and psychiatrist. He discovered Bálint's syndrome. He was born into a German-Jewish family that had settled in Budapest. Rezso Balint’s first writings, published while he was still a medical student, were case studies examining muscular atrophy in hemiplegia. He went on to study tabes dorsalis and the treatment of epilepsy. In 1907, Dr. Balint recorded his observations of a patient who suffered from a unique constellation of neurologic symptoms including fixation of gaze, neglect of objects in his periphery, and misreaching for target objects. The patient was noted to first experience these symptoms following damage to the posterior parietal lobes. This “triple-syndrome complex” was later named “Balint’s Syndrome.” Bálint studied medicine in Budapest, graduating in 1897. He habilitated in 1910, became extraordinary professor in 1914 and full professor in 1917. He died of thyroid cancer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Huntington's Disease
Huntington's disease (HD), also known as Huntington's chorea, is an incurable neurodegenerative disease that is mostly Genetic disorder#Autosomal dominant, inherited. It typically presents as a triad of progressive psychiatric, cognitive, and motor symptoms. The earliest symptoms are often subtle problems with mood or mental/psychiatric abilities, which precede the motor symptoms for many people. The definitive physical symptoms, including a general Ataxia, lack of coordination and an unsteady human gait, gait, eventually follow. Over time, the basal ganglia region of the brain gradually Basal ganglia disease#Huntington's disease, becomes damaged. The disease is primarily characterized by a distinctive hyperkinesia, hyperkinetic movement disorder known as ''chorea.'' Chorea classically presents as uncoordinated, involuntary, "dance-like" body movements that become more apparent as the disease advances. Physical abilities gradually worsen until Motor coordination, coordinated mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcortical Sensory Aphasia
Transcortical sensory aphasia (TSA) is a kind of aphasia that involves damage to specific areas of the temporal lobe of the brain, resulting in symptoms such as poor auditory comprehension, relatively intact repetition, and fluent speech with semantic paraphasias present. TSA is a fluent aphasia similar to Wernicke's aphasia (receptive aphasia), with the exception of a strong ability to repeat words and phrases. The person may repeat questions rather than answer them ("echolalia"). In all of these ways, TSA is very similar to a more commonly known language disorder, receptive aphasia. However, transcortical sensory aphasia differs from receptive aphasia in that patients still have intact repetition and exhibit echolalia, or the compulsive repetition of words. Transcortical sensory aphasia cannot be diagnosed through brain imaging techniques such as functional magnetic resonance imaging (fMRI), as the results are often difficult to interpret. Therefore, clinicians rely on language as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gerstmann Syndrome
Gerstmann syndrome is a neurological disorder that is characterized by a constellation of symptoms that suggests the presence of a lesion usually near the junction of the temporal and parietal lobes at or near the angular gyrus. Gerstmann syndrome is typically associated with damage to the inferior parietal lobule of the dominant hemisphere. It is classically considered a left-hemisphere disorder, although right-hemisphere damage has also been associated with components of the syndrome. It is named after Jewish Austrian-born American neurologist Josef Gerstmann. Symptoms Gerstmann syndrome is characterized by four primary symptoms, collectively referred to as a tetrad: # Dysgraphia/agraphia: deficiency in the ability to write # Dyscalculia/acalculia: difficulty in learning or comprehending mathematics # Finger agnosia: inability to distinguish the fingers on the hand # Left-right disorientation Causes This disorder is often associated with brain lesions in the dominant (us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
