Previous studies indicate that patients with damage to the striatum, such as patients with Parkinson's disease (PD) or Huntington's disease (HD), are impaired in certain categorization tasks, but show no impairment in other categorization tasks. These studies suggest that the striatum may be involved in category learning under some circumstances but not others. One possible role of the striatum in category learning is that these structures are involved in learning nonverbal rules, but only when learning is based on corrective feedback under supervised learning conditions. Such a hypothesis is consistent with current models of striatal functioning. However, it is difficult to draw strong conclusions regarding the proposed role of the striatum based on past work because most of these studies used very different categorization tasks that vary along a number of important dimensions. The proposed research remedies these problems by conducting highly systematic studies of category learning in patients with PD. Factors known to impact the verbalizability of categorization rules will be explored, including (1) whether the rule is linear or nonlinear, (2) whether the rule requires information integration across dimensions or selective attention, and (3) whether the stimulus dimensions are separable or integral. In addition, the nature of training (corrective feedback or observation) will also be examined. These factors likely determine the extent to which the striatum is involved in category learning. Each of these factors will be explored within the framework of a highly successful categorization paradigm that has been used extensively in studies of normal cognition, and recently has been extended to some patient populations and normal aging. The paradigm, called the perceptual categorization task, is rigid enough that strong controls can be placed on factors that vary widely across other tasks, but is flexible enough that each of the factors outlined above can be studied in isolation. Further, quantitative models will be applied to the data of PD patients and controls in order to determine more precisely the nature of any observed category learning deficits in the PD patients.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS041372-02
Application #
6621846
Study Section
Special Emphasis Panel (ZRG1-BBBP-4 (01))
Program Officer
Oliver, Eugene J
Project Start
2002-02-15
Project End
2006-01-31
Budget Start
2003-02-01
Budget End
2004-01-31
Support Year
2
Fiscal Year
2003
Total Cost
$180,005
Indirect Cost
Name
Veterans Medical Research Fdn/San Diego
Department
Type
DUNS #
933863508
City
San Diego
State
CA
Country
United States
Zip Code
92161
Maddox, W Todd; Filoteo, J Vincent (2011) Stimulus range and discontinuity effects on information-integration category learning and generalization. Atten Percept Psychophys 73:1279-95
Maddox, W Todd; Glass, Brian D; O'Brien, Jeffrey B et al. (2010) Category label and response location shifts in category learning. Psychol Res 74:219-36
Filoteo, J Vincent; Salmon, David P; Schiehser, Dawn M et al. (2009) Verbal learning and memory in patients with dementia with Lewy bodies or Parkinson's disease with dementia. J Clin Exp Neuropsychol 31:823-34
Possin, Katherine L; Filoteo, J Vincent; Song, David D et al. (2009) Space-based but not object-based inhibition of return is impaired in Parkinson's disease. Neuropsychologia 47:1694-700
Possin, Katherine L; Filoteo, J Vincent; Song, David D et al. (2008) Spatial and object working memory deficits in Parkinson's disease are due to impairment in different underlying processes. Neuropsychology 22:585-95
Maddox, W Todd; Love, Bradley C; Glass, Brian D et al. (2008) When more is less: feedback effects in perceptual category learning. Cognition 108:578-89
Cagigas, Xavier E; Vincent Filoteo, J; Stricker, John L et al. (2007) Flanker compatibility effects in patients with Parkinson's disease: impact of target onset delay and trial-by-trial stimulus variation. Brain Cogn 63:247-59
Davis, Jennifer D; Filoteo, J Vincent; Kesner, Raymond P (2007) Is short-term memory for discrete arm movements impaired in Huntington's disease? Cortex 43:255-63
Maddox, W Todd; Filoteo, J Vincent; Lauritzen, J Scott (2007) Within-category discontinuity interacts with verbal rule complexity in perceptual category learning. J Exp Psychol Learn Mem Cogn 33:197-218
Salmon, David P; Filoteo, J Vincent (2007) Neuropsychology of cortical versus subcortical dementia syndromes. Semin Neurol 27:7-21

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