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Agnōsía
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 when shown a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psychiatry
Psychiatry is the medical specialty devoted to the diagnosis, treatment, and prevention of deleterious mental disorder, mental conditions. These include matters related to cognition, perceptions, Mood (psychology), mood, emotion, and behavior. Initial psychiatric assessment of a person begins with creating a Medical history, case history and conducting a mental status examination. Laboratory tests, physical examinations, and psychological tests may be conducted. On occasion, neuroimaging or neurophysiological studies are performed. Mental disorders are diagnosed in accordance with diagnostic manuals such as the ''International Classification of Diseases'' (ICD), edited by the World Health Organization (WHO), and the ''Diagnostic and Statistical Manual of Mental Disorders'' (DSM), published by the American Psychiatric Association (APA). The fifth edition of the DSM (DSM-5) was published in May 2013. Treatment may include psychotropics (psychiatric medicines), psychotherapy, su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Striate Cortex
The visual cortex of the brain is the area of the cerebral cortex that processes visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalamus and then reaches the visual cortex. The area of the visual cortex that receives the sensory input from the lateral geniculate nucleus is the primary visual cortex, also known as visual area 1 ( V1), Brodmann area 17, or the striate cortex. The extrastriate areas consist of visual areas 2, 3, 4, and 5 (also known as V2, V3, V4, and V5, or Brodmann area 18 and all Brodmann area 19). Both hemispheres of the brain include a visual cortex; the visual cortex in the left hemisphere receives signals from the right visual field, and the visual cortex in the right hemisphere receives signals from the left visual field. Introduction The primary visual cortex (V1) is located in and around the calcarine fissure in the occipital lobe. Each hemisphere' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Agnosia
Cerebral achromatopsia is a type of color blindness caused by damage to the cerebral cortex of the brain, rather than abnormalities in the cells of the eye's retina. It is often confused with congenital achromatopsia but the underlying physiological deficits of the disorders are completely distinct. A similar, but distinct, deficit called color agnosia exists in which a person has intact color perception (as measured by a matching task) but has deficits in color recognition, such as knowing which color they are looking at. Signs and symptoms Patients with cerebral achromatopsia deny having any experience of color when asked and fail standard clinical assessments like the Farnsworth-Munsell 100-hue test (a test of color ordering with no naming requirements). Patients may often not notice their loss of color vision and merely describe the world they see as being "drab". Most describe seeing the world in "shades of gray". This observation notes a key difference between cerebral and ... [...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] |
Lesion
A lesion is any damage or abnormal change in the tissue of an organism, usually caused by injury or diseases. The term ''Lesion'' is derived from the Latin meaning "injury". Lesions may occur in both plants and animals. Types There is no designated classification or naming convention for lesions. Because lesions can occur anywhere in the body and their definition is so broad, the varieties of lesions are virtually endless. Generally, lesions may be classified by their patterns, sizes, locations, or causes. They can also be named after the person who discovered them. For example, Ghon lesions, which are found in the lungs of those with tuberculosis, are named after the lesion's discoverer, Anton Ghon. The characteristic skin lesions of a varicella zoster virus infection are called '' chickenpox''. Lesions of the teeth are usually called dental caries, or "cavities". Location Lesions are often classified by their tissue types or locations. For example, "skin lesions" or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autotopagnosia
Autotopagnosia from the Greek ''a'' and ''gnosis,'' meaning "without knowledge", ''topos'' meaning "place", and ''auto'' meaning "oneself", autotopagnosia virtually translates to the "lack of knowledge about one's own space," and is clinically described as such. Autotopagnosia is a form of agnosia, characterized by an inability to localize and orient different parts of the body. The psychoneurological disorder has also been referred to as "body-image agnosia" or "somatotopagnosia." ''Somatotopagnosia'' has been argued to be a better suited term to describe the condition. While autotopagnosia emphasizes the deficiencies in localizing only one's own body parts and orientation, ''somatotopagnosia'' also considers the inability to orient and recognize the body parts of others or representations of the body (e.g., manikins, diagrams). Typically, the cause of autotopagnosia is a lesion found in the parietal lobe of the left hemisphere of the brain. However, it as also been noted that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auditory Verbal Agnosia
Auditory verbal agnosia (AVA), also known as pure word deafness, is the inability to comprehend speech. Individuals with this disorder lose the ability to understand language, repeat words, and write from dictation. Some patients with AVA describe hearing spoken language as meaningless noise, often as though the person speaking was doing so in a foreign language. However, spontaneous speaking, reading, and writing are preserved. The maintenance of the ability to process non-speech auditory information, including music, also remains relatively more intact than spoken language comprehension. Individuals who exhibit pure word deafness are also still able to recognize non-verbal sounds. The ability to interpret language via lip reading, hand gestures, and context clues is preserved as well. Sometimes, this agnosia is preceded by cortical deafness; however, this is not always the case. Researchers have documented that in most patients exhibiting auditory verbal agnosia, the discriminati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auditory Agnosia
Auditory agnosia is a form of agnosia that manifests itself primarily in the inability to recognize or differentiate between sounds. It is not a defect of the ear or "hearing", but rather a neurological inability of the brain to process sound meaning. While auditory agnosia impairs the understanding of sounds, other abilities such as reading, writing, and speaking are not hindered. It is caused by bilateral damage to the anterior superior temporal gyrus, which is part of the auditory pathway responsible for sound recognition, the auditory "what" pathway. Persons with auditory agnosia can physically hear the sounds and describe them using unrelated terms, but are unable to recognize them. They might describe the sound of some environmental sounds, such as a motor starting, as resembling a lion roaring, but would not be able to associate the sound with "car" or "engine", nor would they say that it ''was'' a lion creating the noise. All auditory agnosia patients read lips in order ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somatosensory Cortex
The somatosensory system, or somatic sensory system is a subset of the sensory nervous system. The main functions of the somatosensory system are the perception of external stimuli, the perception of internal stimuli, and the regulation of body position and balance (proprioception). It is believed to act as a pathway between the different sensory modalities within the body. As of 2024 debate continued on the underlying mechanisms, correctness and validity of the somatosensory system model, and whether it impacts emotions in the body. The somatosensory system has been thought of as having two subdivisions; *one for the detection of mechanosensory information related to touch. Mechanosensory information includes that of light touch, vibration, pressure and tension in the skin. Much of this information belongs to the sense of touch which is a general somatic sense in contrast to the special senses of sight, smell, taste, hearing, and balance. * one for the nociception detect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astereognosis
Astereognosis (or tactile agnosia if only one hand is affected) is the inability to identify an object by active touch of the hands without other sensory input, such as visual or sensory information. An individual with astereognosis is unable to identify objects by handling them, despite intact elementary tactile, proprioceptive, and thermal sensation. With the absence of vision (i.e. eyes closed), an individual with astereognosis is unable to identify what is placed in their hand based on cues such as texture, size, spatial properties, and temperature. As opposed to agnosia, when the object is observed visually, one should be able to successfully identify the object. Individuals with tactile agnosia may be able to identify the name, purpose, or origin of an object with their left hand but not their right, or vice versa, or both hands. Astereognosis refers specifically to those who lack tactile recognition in both hands. In the affected hand(s) they may be able to identify basic s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Associative Visual Agnosia
Associative visual agnosia is a form of visual agnosia. It is an impairment in Recall (memory), recognition or assigning meaning to a Stimulus (physiology), stimulus that is accurately perception, perceived and not associated with a generalized deficit in intelligence, memory, language or attention. The disorder appears to be very uncommon in a "pure" or uncomplicated form and is usually accompanied by other complex neuropsychological problems due to the nature of the etiology. Affected individuals can accurately distinguish the object, as demonstrated by the ability to draw a picture of it or categorize accurately, yet they are unable to identify the object, its features or its functions. Classification Agnosias are sensory modality specific, usually classified as Visual system, visual, Auditory system, auditory, or Somatosensory system, tactile. Associative visual agnosia refers to a subtype of visual agnosia, which was labeled by Lissauer (1890), as an inability to connect th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
