Visual Form Agnosia

1572 Words4 Pages
bulb-icon

Recommended: Psychology dissertation on visual agnosia

Visual form agnosia is defined as the inability to recognize objects (Goldstein, 2010). To understand the basic concept of visual form agnosia, it is important to first understand that perception and recognition are separate processes. Perception is defined as the ability to become aware of something through our senses, and recognition is the ability to put an object in a group that gives the item meaning. When a person suffers from visual form agnosia, they are generally able to identify the item and distinguish parts of it, but are not able to perceptually accumulate every piece of the item in order to identify the item as complete (Goldstein, 2010). The following is a review of studies concerning the different aspects, theories, and characteristics in visual form agnosia.

The brain is divided into two visual streams, the ventral and the dorsal stream. Goodale and Milner (1998) have suggested that the ventral stream is dedicated to processing vision for perception, and the dorsal stream for vision and action. On the other hand, there is a possibility that the processes in the visuomotor stream can provoke perceptual processes. The propose of the visuomotor stream is that it provides signals, which enhances the person’s ability to distinguish the form of the object. This study illustrated that stimulated perceptual development vanishes if the intended objects only have a difference in respect to their shape, but not width (Goodale & Milner, 1998).

Emphasis has been placed on the disconnection of the dorsal and ventral streams, but there are also many associations between them, and the state of successful integration of their ‘complementary contributions’ can help humans with goal-directed adapted behavior (Goodale & Servos, ...

... middle of paper ...

...
Goodale, M.A., & Servos, P. (1995). Preserved visual imagery in visual form agnosia. Neuropsychologia, 33 (11), p. 1383-1394.

Goldstein, E.B. (2010). Sensation and perception: Eighth edition. California: Linda Schreiber.

McIntosh, R.D., Milner, A.D., Mon-Williams, M., & Tresilian, J.R. (2001). Monocular and binocular distance cues: Insights from visual form agnosia I (of III). Exp Brain Res, 139, p. 127-136

Milner, A. D., & Schenk, T. (2006). Concurrent visuomotor behaviour improves form discrimination in a patient with visual form agnosia. European journal of neuroscience, 24 (5), p. 1495-1503.

Vercera, S.P. (2001). Dissociating ‘what’ and ‘how’ in visual form agnosia: A computational investigation. Nueropsychologia, 40, p. 187-204.

Weiskrantz, L. (1997). Consciousness lost and found: A neuropsychological exploration. Oxford University Press, p. 294

Show More
Related

  • What is Visual Crowding?

    960 Words  | 2 Pages

    ...ical pathway. In Dorsal pathway, it provides visual information that detects movement of the objects while in Ventral pathway; it provides visual information about recognition of the object. The distinct properties of location (where) and shape (what) are estimates from very differently sized regions. (Majaj, M. J. & Palomares, M. & Pelli D.G.(2004)

    Read More

  • Character Analysis: The Man Who Mistook His Wife For A Hat

    1054 Words  | 3 Pages

    Agnosia is a rare disorder that revolves around the inability to recognize things, things differ from what type of agnosia is in question. Agnosia derived from the Greek word “agnosia.” The translated meaning is ignorance or without knowledge. On the norm, agnosia affects one single information pathway in the brain. The two most common forms of agnosia are visual and auditory. The senses themselves are still intact and there is no loss of memory. Intact, in this case, means that they are still there. Even though many have suffered from visual agnosia like Dr.P, they would still be able to use their eyesight. However, it would not be as accurate as an average person. These type of patients would usually attempt to pick up an object. Once the object is in their hands, they would use their sense of touch, or their tactile information pathway, to distinguish what the object truly is. The main cause for agnosia, is brain damage. This damage affects certain pathways. The pathways in the brain connects primary sensory processing areas to areas that store information and knowledge. Lesions, or damage in tissues or organs, in the parietal and temporal lobes is also served to cause agnosia. Lesions could be caused by strokes, head traumas, or encephalitis. Any additional conditions that can damage the brain may also be a result in agnosia. Examples of

    Read More

  • Mental Rotation Of Images

    1435 Words  | 3 Pages

    Although the objectives of the two experiments I discussed were different, result were the same regardless as to what the differences might have been. In all experiment including the one I did, results were concurrent. Findings supported the hypothesis that was set forth: As angular rotation increased, reaction time will also increase. Thus, showing reaction times do serve as an appropriate method for analyzing how quickly the brain reacts to mental rotations of images.

    Read More

  • Perceptions of Reality and False Reality

    1483 Words  | 3 Pages

    In “The Anatomy of Judgmen”t, M. L. J. Abercrombie discusses how information is gained through our perception. Abercrombie claims that interpretation is a very complicated task that people have been learning to exercise since birth. Each person has a different way of interpreting the objects or situations they see, because people often relate their own past experiences. She also explains two important concepts: schemata and context. She defines schemata as a way our mind functions by understanding new things perceived through sight, by relating it to an individual’s past experiences. Past experiences help interpret what is seen further, if the object fits one’s expectation or their schemata, and not something different from their past experiences. Her fundamental insight is that seeing is more complex than just passively registering what is seen, and consists of a form judgment for...

    Read More

  • Substance Abuse Counselor Career

    905 Words  | 2 Pages

    Renner, T., Feldman, R., Majors, M., Morrissey, J., & Mae, L. (2011). States of Consciousness. Psychsmart (pp. 99-107). New York: McGraw-Hill.

    Read More

  • What is Perceptual Agnosias?

    1884 Words  | 4 Pages

    Agnosia is a clinical condition characterized by disordered perception situated at an intermediate stage between primary sensory defect and general intellectual dysfunction (Hécaen & Albert, 1978; Mather, 2009). Agnosias are described as the loss of ability to recognize objects, persons, sounds, shapes, or smells while the specific sense is not impaired nor is there any significant memory loss (Mather, 2009) A person can have a deficit in the visual, auditory, olfactory, somatosensory system even the sense of hearing, smell, or touch functions normally (Gazzaniga, Ivry & Mangun, 2014). The term was coined by Sigmund Freud, who derived it from the Greek a – (“without”) and agnosis (“knowledge). According to Riddoch et al. (2008) agnosias were first described by Liassauer in 1890. Liassauer (1890) proposed the existence of apperceptive agnosia, Kussmaul (1877) first described a patient with pure word deafness, and Bernard (1889) noted an amusia. Since that time, many other cases have been reported (Mendez, & Geehan, 1988).

    Read More

  • Compare and Contrast the Different Perceptual Disorders that Disrupt Visual Perception

    708 Words  | 2 Pages

    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...

    Read More

  • Bonded Awareness Analysis

    648 Words  | 2 Pages

    A few of the forms are Intentional blindness, Change blindness, and focalism and the focusing illusion. Intentional blindness is our inability to notice certain obvious things about a situation. When we are told to

    Read More

  • Essay On Conscious Awareness

    969 Words  | 2 Pages

    ...I) to show activation in the dorsal cortex during unconscious perception. Therefore, if neuroimaging evidence demonstrates that dorsal stream is activated during unconscious processing, then this can strengthen the conclusions drawn from their experiment.

    Read More

  • What is Change Blindness?

    2072 Words  | 5 Pages

    ...erent factors may affect how, when, and to what extent change blindness occurs. In doing so, we are interested in the reaction times and accuracy of subjects in identifying a difference between an original and altered image. Other implications that we aim to replicate are the effects of the type of change including: how the changed object in question is positioned (centrally or peripherally), as well as which types of specific differences lend themselves to be better noticed or ignored (changing the color of an object, and the presence or absence of an object). We hypothesize that there will be a significant effect displayed in correspondence to color changes, in both accuracy and speed. Also, we hypothesize that changes made to the color or mere presence of an object will be significantly more noticeable when centrally viewed, as opposed to those in the periphery.

    Read More

  • Milner Face Perceptions

    921 Words  | 2 Pages

    The importance of properly recognizing faces has given rise to understanding the neurological mechanisms behind it. According to Milner, Kolb, and Taylor (2004), the right hemisphere plays a dominant role in facial recognition. The study that was done in this article was intended to compare the effects of circumscribed lesions of all the lobes except occipital regarding the perception of faces. There was a control group and then four groups of patients; each having undergone a unilateral brain operation. After the procedure, 19 pictures were shown, 9 male and 10 female. For 10 of the pictures, the face that was compared was shown in normal orientation and for the remaining 9 pictures, the face of comparison was the mirror image of the normal orientation. (Milner et al.,1983) found that the results supported the original statement that right temporal lobe lesions show multiple changes in face perception. The absence of a choice for the left visual field in patients with lesions in right temporal or right parieto-occipital lobes is evidence that both of those areas play a role in the normal processing of faces. This briefly describes the study that Milner conducted along with her colleagues. Milner’s contribution to understanding the perception of faces is still used today and other scientists continue to build on her

    Read More

  • Astereognotic Disorders: Stereognosis

    819 Words  | 2 Pages

    268). This disorder is often a result of damage to one or more of these areas, illustrating the complex, separate systems involved in perceiving, integrating, and making observations on this information, as well as the possibility for these systems to become altered or interrupted as a result of lesions, tumours, or other forms of damage. It is also worth noting that those suffering from Alzheimer’s or other forms of dementia show a reduction in their stereognosis ability, showing that some neurological diseases may impact these systems as well (Gerstmann, 2001, p. 271). Apart from the impact on making associations between previously perceived objects and immediate tactile sensory input, individuals with this disorder would rarely experience significant distress or impact to their quality of life as it does not directly affect interactions with others or their

    Read More

  • Finacial Orientation Theory

    664 Words  | 2 Pages

    These results reveal that in infants there is an orientation preference in newborns. It is believed that when adults provide stimuli to infants their faces will be recognized by infants in their original orientations and this in turns makes it possible that rapid learning when it comes to faces is orientation-specific. In conclusion to these findings, propose that this prototype, facial representation, includes information about faces that is orientation-specific. (Slater, Quinn, Hayes, & Brown,

    Read More

  • Neuroplasticity

    1643 Words  | 4 Pages

    S.A. Clark, T. A. (1988). Receptive fields in the body-surface map in adult cortex defined by temporally correlated inputs. Nature, 332.

    Read More

  • Understanding Perception: A Human and Animal Perspective

    1345 Words  | 3 Pages

    Patients with prosopagnosia have the inability to recognize the faces of familiar people in their life. It is quite tragic because they can’t quickly recognize loved ones such as family and friends. This is mainly caused by damage in the left upper quadrant which suggests a lesion on the right cerebral area. The impairment of the right cerebral area is rather devastating because the right side of the brain is commonly used for facial proccessing. Within the right hemisphere of the brain the fusiform gyrus and the lingual gyrus were negatively affected. The function of the fusiform gyrus is mainly used for facial recognition. In the article “What is Face Blindness?” by Julie Leibach, she observes a woman who has suffered from prosopagnosia since she was five. Leibach discovers that “[Lisa tried] to keep track of the brothers, she would usually memorize what color shirt each was wearing.” The inability to use the fusiform gyrus in perception will not allow a person to recall or remember details of another person’s face. Without the fusiform gyrus the only way prosopagnosia patients could recognize a person is through their hair, voice, or even clothes. The lingual gyrus also affects a prosopagnosia patient’s brain. The main function of the lingual gyrus is to proccess vision. It also plays a major role in proccessing very complex details of

    Read More

More about Visual Form Agnosia

Open Document