There are many perceptual disorders but first we must cover what a perceptual disorder actually is. Perceptual disorders are cognitive disorders characterised by impaired ability to perceive objects through sense organs as a result of the brain or eye being damaged. In this essay I will compare and contrast a variety of perceptual disorders and provide insight as to how they are caused by deficits.
The first disorder that will be mentioned is Agnosia and the two types of Agnosia; Apperceptive Agnosia and Associative Agnosia. Agnosia in general is a failure of recognition which is not attributed to a sensory deficit. There is a visual specific Agnosia which interferes with visual stimuli recognition, in particular inability to recognise objects from visual information. As prior mentioned there are two forms one being, Apperceptive Agnosia. This is the inability to recognise objects and have impaired ability to draw objects. The second type of Agnosia is associative Agnosia, this is the inability to make meaningful associations between objects that are visually presented. While they can copy unlike Apperceptive they can recognise these drawings. In Associative damage is usually located in borders between optical and temporal lobes in both hemispheres but it can be limited to one. Damage in Apperceptive which not always in a fixed place usually has high correlation of damage caused to the occipital lobes usually in the left hemisphere which causes these recognition problems.
Lissauer (1890) made an important distinction between Apperceptive and Associative Agnosia. He found that Apperceptive recognition can occur without acuity or other sensory functions whereas associative cannot. Ettlinger (1956) can follow on with his research sh...
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...ioned that Blindsight may be a direct result of a scotoma it has also been noted that it is generally caused by lesions to their striate cortex or their primary visual cortex.
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The ultimate goal for a system of visual perception is representing visual scenes. It is generally assumed that this requires an initial ‘break-down’ of complex visual stimuli into some kind of “discrete subunits” (De Valois & De Valois, 1980, p.316) which can then be passed on and further processed by the brain. The task thus arises of identifying these subunits as well as the means by which the visual system interprets and processes sensory input. An approach to visual scene analysis that prevailed for many years was that of individual cortical cells being ‘feature detectors’ with particular response-criteria. Though not self-proclaimed, Hubel and Wiesel’s theory of a hierarchical visual system employs a form of such feature detectors. I will here discuss: the origins of the feature detection theory; Hubel and Wiesel’s hierarchical theory of visual perception; criticism of the hierarchical nature of the theory; an alternative theory of receptive-field cells as spatial frequency detectors; and the possibility of reconciling these two theories with reference to parallel processing.
The symptoms of a right-hemisphere stroke are very much similar like the symptoms Mr. Fix-it is experiencing. For example, both suggest that functions on the left side of the body are completely neglected; therefore, the left visual section of the body does not respond effectively to stimuli due to the neglect. Damage to the right occipital lobe is very likely. The patient may have experienced some damage to areas 18 and 19 of the occipital lobe. “Damage to these association areas resulted in the patient’s failure to recognize items even when they have been seen before”, such as Mr. Fix-it’s deficiency to recognize geometric shapes (Carlson, 2010). Moreover, the patient could have also experience damage in the frontal lobe, specifically on area 8, in which it could have r...
Understanding of Children with Congenital Profound Visual Impairment." British Journal of Developmental Psychology, 22.1 (2004): 1-17.
The ‘where visual pathway’ is concerned with constructing three dimensional representations of the environment and helps our brain to navigate where things are, independently of what they are, in space in relation to itself (Mishkin & Ungerleider & Macko, 1983).... ... middle of paper ... ... The 'Standard' of the 'Standard'.
Classical theories demonstrating the inattentional blindness paradigm are (1) the perceptual load, (2) inattentional amnesia and (3) expectation.
Sajda P. & Finkle, L.H. (1995) Intermediate Visual Representations and the Construction of Surface Perception. Journal of Cognitive Neuroscience, 7, 267-291.
[19]Tranel, D., Damasio, H., Damasio, A.R., 1995. Double dissociation between overt and covert recognition. Journal of Cognitive Neuroscience 7, 425–432.
Sensory Processing Disorder is a condition that exists when sensory signals don’t get controlled into proper responses. It prevents part of the brain from receiving information to understand everything correctly. Sensory processing is the way our nervous system receives messages from the senses and turns them into appropriate motor and behavioral responses. An individual with sensory processing disorder finds it complicated to process and operates from receiving information. Sensory Process Disorder develops when the child is in the womb and stays with the person throughout their life. Sensory Processing Disorder creates difficulty in interaction with others, daily routines, socially, behaviorally, emotionally and could have effects on
To test these hypotheses, we first collected a two point discriminator containing a variety of distances for two points. The point distances on the discriminator included values of.25 millimeters being the smallest, ...
Amblyopia is a condition in which visual acuity in one eye is greatly reduced. It is caused by lack of stimulation or disuse during visual development (Rose, 1998). Because the eye is not fully developed at birth (Jarvis, 1992, as cited in Rose, 1998), infants need stimulation to complete the visual neural pathway. When one or both eyes are inhibited, for example due to misalignment of one eye (strabismus) or a large difference in refractive power between two eyes (anisometropia), the neural pathway for the inhibited eye develops abnormally, or does not develop at all. At approximately six years of age eye development is complete (Stager, 1990, as cited in Rose, 1998). Before visual development is complete amblyopia can be treated. If it is caught and treated at an early age, normal vision can be preserved (Rose, 1998).
Broadbent’s (1958) filter theory of attention proposes that there is a filter device between sensory identification and short-term memory. This filter is used as a buffer that allows an individual to manage several different forms of simultaneous stimuli where one stimulus is processed in the filter whilst the second stimulus is kept in the buffer to be processed at a later time (Broadbent, 1958). The extent to which this theory of attention can provide an effective explanation of how we attend to objects is questionable due to the fact that Broadbent’s filter theory is designed to explain auditory attention as opposed to visual attention. In this sense, Broadbent’s filter theory cannot explain how we attend to objects and thus provides no useful information for such attention. An object was making a sound co...
Perception is defined as the awareness of the world through the use of the five senses, but the concept of perception is often used to isolate one person’s point of view, so how reliable can perception be if no one person’s is exactly the same? The word perception itself is riddled with different, well, perceptions of its meaning. When some hear the word, they might automatically think of it as something innately flawed, that can easily be fooled by illusions, while others may think of its usefulness when avoiding scalding a hand on a hot stove. I am here to agree with both and to argue that perception is something necessary and helpful, and something that should be scrutinized for its flaws. By looking at perception as a way of knowing in the context of memory and human sciences, it can be concluded that perception can contribute to the acquisition of knowledge by constructing a foundation on which incoming stimuli from the environment are able to be quickly interpreted and acted upon, but perception can also hinder the acquisition of knowledge by wrongly interpreting those stimuli, causing inappropriate reactions.
Each one of us lives in our own unique world of perception. As individuals, we may experience life in an entirely different way through our senses and life experiences. Therefore, perception can be tricky since it is very personal to each one of us. According to the Merriam-Webster online dictionary, perception has three meanings; (1) “the way you think about or understand someone or something,” (2) “the ability to understand or notice something easily,” and, (3) “the way that you notice or understand something using one of your senses” (2014, para. 1). C.S. Lewis said, “What you see and what you hear depends a great deal on where you are standing. It also depends on what sort of person you are” (n.d., para. 11). In other words,
The patient is a 43 year-old female insurance sale agent who came to the clinic for annual eye examination. She complained from symptoms of ocular irritation and burning when she wakes up in the morning. She felt ocular dryness in the afternoon and the eyes look red. She has also noted different height of her eyelids when putting make-up on. She denied significant problems with driving, TV watching, computer use or reading. She also denied flashes, floaters or diplopia. The patient was myopia with no prior eye surgeries, previous history of eye trauma, amblyopia or strabismus. She did not use any medication. The past ocular family history was negative. Social history was negative, too.
There are many different Visual Perception principles in perception. The main principles are Gestalt. Gestalt is a German word meaning 'form' or 'shape'. Gestalt psychologists formulated a series of principles that describe how t...