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Comparative Neuropsychology refers to an approach used for understanding human brain functions. It involves the direct evaluation of clinical neurological populations by employing experimental methods originally developed for use with nonhuman animals.
Over many decades of animal research, methods were perfected to study the effects of well-defined brain lesions on specific behaviors, and later the tasks were modified for human use. Generally the modifications involve changing the reward from food to money, but standard administration of the tasks in humans still involves minimal instructions, thus necessitating a degree of procedural learning in human and nonhuman animals alike.
Currently, comparative neuropsychology is used with neurological patients to link specific deficits with localized areas of the brain.
The comparative neuropsychological approach employs simple tasks that can be mastered without relying upon language skills. Precisely because these simple paradigms do not require linguistic strategies for solution, they are especially useful for working with patients whose language skills are compromised, or whose cognitive skills may be minimal.
Comparative neuropsychology contrasts with the traditional approach of using tasks that rely upon linguistic skills, and that were designed to study human cognition. Because important ambiguities about its heuristic value had not been addressed empirically, only recently has comparative neuropsychology become popular for implementation with brain-damaged patients.
Within the past decade, comparative neuropsychology has had prevalent use as a framework for comparing and contrasting the performances of disparate neurobehavioral populations on similar tasks.
Comparative neuropsychology involves the study of brain-behavior relationships by applying experimental paradigms, used extensively in animal laboratories, for testing human clinical populations.<1> Popular paradigms include delayed reaction tasks, discrimination and reversal learning tasks, and matching- and nonmatching-to-sample.<2> A paradigm is typical example of how these experiments are done. These task are used to test animals and relate them to human brain functioning. Such tasks were perfected on experimental animals having well defined brain lesions, and adapted for the sensory and motor capabilities of human neurological patients.<3> Researchers give lesions to animals in order to better understand what humans with the same condition are experiencing. An example of the application of comparative neuropsychology to clinical populations is given: patients with a history of long term alcohol abuse were tested on delayed reaction paradigms, and the findings have been useful in clarifying the contribution of damaged frontal cortical-subcortical brains systems to their cognitive impairments.<4> In this studies on animals were used to understand frontal cortex damage. It was comparing the brains of test animals like primates and mice to understand how people with damage resulting from alcohol abuse.
George Ettlinger was one of the few who actively combined human and animal research, and he did so consistently throughout his scientific career.<5> The importance of the inferior temporal neocortex in visual discrimination learning and remembering in macaque monkeys was established in the 1950s by several investigators, including George Ettlinger.<6> The importance of ventral temporal lobe vision was also established by George Ettlinger by comparative neuropsychology. Using primates to learn about human brain structure was used by Ettlinger Although the monkeys with inferotemporal or latero-ventral prestriate ablation were visually ‘agnosic’ their sensory status was resolutely normal, with the exception of chromatic discrimination, which is irrelevant to achromatic shape perception.<7> In 1966 George Ettlinger, together with the psychologist Colin Blakemore and the neurosurgeon Murray Falconer, described their investigation of whether any correlation exists between pre-operative intelligence and the severity of mesial temporal sclerosis in temporal lobe specimens excised to treat intractable epilepsy.<8> While this study is not very well known because it failed to draw conclusion or correlation it was still important. It is known as a forerunner of what has become one of the potentially most interesting techniques for exploring the relationship between certain aspects of human memory and temporal lobe structures.<9>
One of the reasons comparative neuropsychology is a relatively unknown field is because few people chose to study both the brains of animals and humans independently. One study in 1978 “Ability of Chimpanzees to Respond to Symbols of Quantity in Comparison with That of Children and of Monkeys” sought to better understand the differences between monkey, chimpanzees, and human children. The main purpose of this experiment was to assess the conceptual ability of chimpanzees. The researchers of this study were more surprise that the non-human animal subjects, and particular chimpanzees, were more variable both within and between subjects than were children in responding to the concept of some.<10> The study showed there was variability between subjects, but human children ages of four were better at conceptualizing quantities than monkeys and chimpanzees. This is one several comparative neuropsychology studies that has been used to better inform us about the brains of primates and humans. How are they alike and how are they different are questions neuropsychologists seek to be better understand. In addition to this comparative neuropsychology see to better understand how to use the information gained from the brains of animals to benefit human research.
<6.Cowey, Dean, & Weiskrantz, 1998>
<7.Cowey, Dean, & Weiskrantz, 1998>
<8.Oxbury & Oxbury, 1998>
<9.Oxbury & Oxbury, 1998>
<10.Brown, Lenneberg, & Ettlinger, 1978)>
<Oscar-Berman, M., & Bardenhagen, F. (1998). Nonhuman primate models of memory dysfunction in neurodegenerative disease: Contributions from Comparative Neuropsychology. In A. Tröster (Ed.), Memory in neurodegenerative disease (pp. 3-20). New York: Cambridge University Press.>
<Brown, D. P., Lenneberg, E. H., & Ettlinger, G. (1978). Ability of chimpanzees to respond to symbols of quantity in comparison with that of children and of monkeys. Journal Of Comparative and Physiological Psychology, 815-820.>
<Cowey, A., Dean, P., & Weiskrantz, L. (1998). Ettlinger at Bay: can visual agnosia be explained by low-level visual impairments? Chicago: Oxford University Chicago.>
<M., O.-B. (1994). A comparative neuropsychological approach to alcoholism and the brain. Retrieved from pubmed.gov: http://www.ncbi.nlm.nih.gov/pubmed/8974348>
<Milner, A. D. (1998). Introduction: Comparative Neuropsychology. Chicago: Oxford University Press. Oxbury, J. M., & Oxbury, S. (1998). Memory and the human temporal lobes. Chicago: Oxford University Press.>