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Dissociation of category-learning systems via brain potentials.

Morrison RG, Reber PJ, Bharani KL, Paller KA - Front Hum Neurosci (2015)

Bottom Line: Categorization accuracy was similar for the two distributions.A stimulus-locked Late Positive Complex (LPC) associated with explicit memory updating was modulated by accuracy in the RB, but not the II task.These results provide additional evidence for distinct brain mechanisms supporting RB vs. implicit II category learning and use.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, Neuroscience Institute, Loyola University Chicago Chicago, IL, USA.

ABSTRACT
Behavioral, neuropsychological, and neuroimaging evidence has suggested that categories can often be learned via either an explicit rule-based (RB) mechanism critically dependent on medial temporal and prefrontal brain regions, or via an implicit information-integration (II) mechanism relying on the basal ganglia. In this study, participants viewed sine-wave gratings (Gabor patches) that varied on two dimensions and learned to categorize them via trial-by-trial feedback. Two different stimulus distributions were used; one was intended to encourage an explicit RB process and the other an implicit II process. We monitored brain activity with scalp electroencephalography (EEG) while each participant: (1) passively observed stimuli represented of both distributions; (2) categorized stimuli from one distribution, and, 1 week later; (3) categorized stimuli from the other distribution. Categorization accuracy was similar for the two distributions. Subtractions of Event-Related Potentials (ERPs) for correct and incorrect trials were used to identify neural differences in RB and II categorization processes. We identified an occipital brain potential that was differentially modulated by categorization condition accuracy at an early latency (150-250 ms), likely reflecting the degree of holistic processing. A stimulus-locked Late Positive Complex (LPC) associated with explicit memory updating was modulated by accuracy in the RB, but not the II task. Likewise, a feedback-locked P300 ERP associated with expectancy was correlated with performance only in the RB, but not the II condition. These results provide additional evidence for distinct brain mechanisms supporting RB vs. implicit II category learning and use.

No MeSH data available.


Related in: MedlinePlus

ERPs showing the LPC ERP for both (A) RB and (D) II conditions in a cluster of parietal electrodes (12 marked electrodes surrounding Pz; see Figure 3C for precise electrode locations). Topographic maps representing correct minus incorrect subtractions from 500–600 ms for (B) RB and (E) II ERPs. Scatterplots showing the relationship of accuracy to the correct minus incorrect mean amplitude ERP subtractions from 500–600 ms for three parietal electrodes near Pz (indicated on the corresponding topographic maps) for (C) RB and (F) II conditions.
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Figure 7: ERPs showing the LPC ERP for both (A) RB and (D) II conditions in a cluster of parietal electrodes (12 marked electrodes surrounding Pz; see Figure 3C for precise electrode locations). Topographic maps representing correct minus incorrect subtractions from 500–600 ms for (B) RB and (E) II ERPs. Scatterplots showing the relationship of accuracy to the correct minus incorrect mean amplitude ERP subtractions from 500–600 ms for three parietal electrodes near Pz (indicated on the corresponding topographic maps) for (C) RB and (F) II conditions.

Mentions: Based on our predictions, stimulus-locked analyses were focused on an early occipital N1 ERP (Figure 6) and a later parietal LPC ERP (Figure 7) in the Model-Conforming Group.


Dissociation of category-learning systems via brain potentials.

Morrison RG, Reber PJ, Bharani KL, Paller KA - Front Hum Neurosci (2015)

ERPs showing the LPC ERP for both (A) RB and (D) II conditions in a cluster of parietal electrodes (12 marked electrodes surrounding Pz; see Figure 3C for precise electrode locations). Topographic maps representing correct minus incorrect subtractions from 500–600 ms for (B) RB and (E) II ERPs. Scatterplots showing the relationship of accuracy to the correct minus incorrect mean amplitude ERP subtractions from 500–600 ms for three parietal electrodes near Pz (indicated on the corresponding topographic maps) for (C) RB and (F) II conditions.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493768&req=5

Figure 7: ERPs showing the LPC ERP for both (A) RB and (D) II conditions in a cluster of parietal electrodes (12 marked electrodes surrounding Pz; see Figure 3C for precise electrode locations). Topographic maps representing correct minus incorrect subtractions from 500–600 ms for (B) RB and (E) II ERPs. Scatterplots showing the relationship of accuracy to the correct minus incorrect mean amplitude ERP subtractions from 500–600 ms for three parietal electrodes near Pz (indicated on the corresponding topographic maps) for (C) RB and (F) II conditions.
Mentions: Based on our predictions, stimulus-locked analyses were focused on an early occipital N1 ERP (Figure 6) and a later parietal LPC ERP (Figure 7) in the Model-Conforming Group.

Bottom Line: Categorization accuracy was similar for the two distributions.A stimulus-locked Late Positive Complex (LPC) associated with explicit memory updating was modulated by accuracy in the RB, but not the II task.These results provide additional evidence for distinct brain mechanisms supporting RB vs. implicit II category learning and use.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, Neuroscience Institute, Loyola University Chicago Chicago, IL, USA.

ABSTRACT
Behavioral, neuropsychological, and neuroimaging evidence has suggested that categories can often be learned via either an explicit rule-based (RB) mechanism critically dependent on medial temporal and prefrontal brain regions, or via an implicit information-integration (II) mechanism relying on the basal ganglia. In this study, participants viewed sine-wave gratings (Gabor patches) that varied on two dimensions and learned to categorize them via trial-by-trial feedback. Two different stimulus distributions were used; one was intended to encourage an explicit RB process and the other an implicit II process. We monitored brain activity with scalp electroencephalography (EEG) while each participant: (1) passively observed stimuli represented of both distributions; (2) categorized stimuli from one distribution, and, 1 week later; (3) categorized stimuli from the other distribution. Categorization accuracy was similar for the two distributions. Subtractions of Event-Related Potentials (ERPs) for correct and incorrect trials were used to identify neural differences in RB and II categorization processes. We identified an occipital brain potential that was differentially modulated by categorization condition accuracy at an early latency (150-250 ms), likely reflecting the degree of holistic processing. A stimulus-locked Late Positive Complex (LPC) associated with explicit memory updating was modulated by accuracy in the RB, but not the II task. Likewise, a feedback-locked P300 ERP associated with expectancy was correlated with performance only in the RB, but not the II condition. These results provide additional evidence for distinct brain mechanisms supporting RB vs. implicit II category learning and use.

No MeSH data available.


Related in: MedlinePlus