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Procedural-based category learning in patients with Parkinson's disease: impact of category number and category continuity.

Filoteo JV, Maddox WT - Front Syst Neurosci (2014)

Bottom Line: Previously we found that Parkinson's disease (PD) patients are impaired in procedural-based category learning when category membership is defined by a nonlinear relationship between stimulus dimensions, but these same patients are normal when the rule is defined by a linear relationship (Maddox and Filoteo, 2001; Filoteo et al., 2005a,b).In the present study, we further examined the nature of PD patients' procedural-based deficit in two experiments designed to examine the impact of (1) the number of categories, and (2) category discontinuity on learning.Theoretically, this deficit might be related to dysfunctional communication among medium spiny neurons within the striatum, particularly given that these are cholinergic neurons and a cholinergic deficiency could underlie some of PD patients' cognitive impairment.

View Article: PubMed Central - PubMed

Affiliation: Veterans Administration San Diego Healthcare System San Diego, CA, USA ; Department of Psychiatry, University of California San Diego, CA, USA.

ABSTRACT
Previously we found that Parkinson's disease (PD) patients are impaired in procedural-based category learning when category membership is defined by a nonlinear relationship between stimulus dimensions, but these same patients are normal when the rule is defined by a linear relationship (Maddox and Filoteo, 2001; Filoteo et al., 2005a,b). We suggested that PD patients' impairment was due to a deficit in recruiting "striatal units" to represent complex nonlinear rules. In the present study, we further examined the nature of PD patients' procedural-based deficit in two experiments designed to examine the impact of (1) the number of categories, and (2) category discontinuity on learning. Results indicated that PD patients were impaired only under discontinuous category conditions but were normal when the number of categories was increased from two to four. The lack of impairment in the four-category condition suggests normal integrity of striatal medium spiny cells involved in procedural-based category learning. In contrast, and consistent with our previous observation of a nonlinear deficit, the finding that PD patients were impaired in the discontinuous condition suggests that these patients are impaired when they have to associate perceptually distinct exemplars with the same category. Theoretically, this deficit might be related to dysfunctional communication among medium spiny neurons within the striatum, particularly given that these are cholinergic neurons and a cholinergic deficiency could underlie some of PD patients' cognitive impairment.

No MeSH data available.


Related in: MedlinePlus

Accuracy rates for PD patients and NC participants (A) Four Category and (B) Two Category conditions in Experiment 1. (Error bars are in standard error of the mean).
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Figure 5: Accuracy rates for PD patients and NC participants (A) Four Category and (B) Two Category conditions in Experiment 1. (Error bars are in standard error of the mean).

Mentions: Accuracy rates for the Four-Category condition of Experiment 1 are displayed in Figure 5A and were analyzed using a 2 (group: PD vs. NC) × 6 (blocks 1–6) mixed-design ANOVA. Results revealed a main effect of block, F(5, 110) = 37.02, p < 0.001, η2p = 0.63, with both PD and NC participants' performance improving across the trials. However, there was no main effect of group, F(1, 22) = 0.08, p = 0.78, η2p = 0.00, and no group by block interaction, F(5, 110) = 0.35, p = 0.88, η2p = 0.02. Accuracy rates for the Two-Category condition are displayed in Figure 5B and were analyzed using the same ANOVA design. Results indicated a main effect of block, F(5, 110) = 11.88, p < 0.001, η2p = 0.37, but no main effect of group, F(1, 22) = 0.21, p = 0.65, η2p = 0.00, and no group by block interaction, F(5, 110) = 1.23, p = 0.30, η2p = 0.06.


Procedural-based category learning in patients with Parkinson's disease: impact of category number and category continuity.

Filoteo JV, Maddox WT - Front Syst Neurosci (2014)

Accuracy rates for PD patients and NC participants (A) Four Category and (B) Two Category conditions in Experiment 1. (Error bars are in standard error of the mean).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3928591&req=5

Figure 5: Accuracy rates for PD patients and NC participants (A) Four Category and (B) Two Category conditions in Experiment 1. (Error bars are in standard error of the mean).
Mentions: Accuracy rates for the Four-Category condition of Experiment 1 are displayed in Figure 5A and were analyzed using a 2 (group: PD vs. NC) × 6 (blocks 1–6) mixed-design ANOVA. Results revealed a main effect of block, F(5, 110) = 37.02, p < 0.001, η2p = 0.63, with both PD and NC participants' performance improving across the trials. However, there was no main effect of group, F(1, 22) = 0.08, p = 0.78, η2p = 0.00, and no group by block interaction, F(5, 110) = 0.35, p = 0.88, η2p = 0.02. Accuracy rates for the Two-Category condition are displayed in Figure 5B and were analyzed using the same ANOVA design. Results indicated a main effect of block, F(5, 110) = 11.88, p < 0.001, η2p = 0.37, but no main effect of group, F(1, 22) = 0.21, p = 0.65, η2p = 0.00, and no group by block interaction, F(5, 110) = 1.23, p = 0.30, η2p = 0.06.

Bottom Line: Previously we found that Parkinson's disease (PD) patients are impaired in procedural-based category learning when category membership is defined by a nonlinear relationship between stimulus dimensions, but these same patients are normal when the rule is defined by a linear relationship (Maddox and Filoteo, 2001; Filoteo et al., 2005a,b).In the present study, we further examined the nature of PD patients' procedural-based deficit in two experiments designed to examine the impact of (1) the number of categories, and (2) category discontinuity on learning.Theoretically, this deficit might be related to dysfunctional communication among medium spiny neurons within the striatum, particularly given that these are cholinergic neurons and a cholinergic deficiency could underlie some of PD patients' cognitive impairment.

View Article: PubMed Central - PubMed

Affiliation: Veterans Administration San Diego Healthcare System San Diego, CA, USA ; Department of Psychiatry, University of California San Diego, CA, USA.

ABSTRACT
Previously we found that Parkinson's disease (PD) patients are impaired in procedural-based category learning when category membership is defined by a nonlinear relationship between stimulus dimensions, but these same patients are normal when the rule is defined by a linear relationship (Maddox and Filoteo, 2001; Filoteo et al., 2005a,b). We suggested that PD patients' impairment was due to a deficit in recruiting "striatal units" to represent complex nonlinear rules. In the present study, we further examined the nature of PD patients' procedural-based deficit in two experiments designed to examine the impact of (1) the number of categories, and (2) category discontinuity on learning. Results indicated that PD patients were impaired only under discontinuous category conditions but were normal when the number of categories was increased from two to four. The lack of impairment in the four-category condition suggests normal integrity of striatal medium spiny cells involved in procedural-based category learning. In contrast, and consistent with our previous observation of a nonlinear deficit, the finding that PD patients were impaired in the discontinuous condition suggests that these patients are impaired when they have to associate perceptually distinct exemplars with the same category. Theoretically, this deficit might be related to dysfunctional communication among medium spiny neurons within the striatum, particularly given that these are cholinergic neurons and a cholinergic deficiency could underlie some of PD patients' cognitive impairment.

No MeSH data available.


Related in: MedlinePlus