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Impaired Early Attentional Processes in Parkinson's Disease: A High-Resolution Event-Related Potentials Study.

Bocquillon P, Bourriez JL, Palmero-Soler E, Defebvre L, Derambure P, Dujardin K - PLoS ONE (2015)

Bottom Line: PD patients displayed fewer N2 generators than HCs in both the DLPFC and the ACC, for all types of stimuli.In contrast to controls, PD patients did not show any differences between their generators for different N2 subcomponents.Our data suggest that impaired inhibition in PD results from dysfunction of the DLPFC and the ACC during the early stages of attentional processes.

View Article: PubMed Central - PubMed

Affiliation: Clinical Neurophysiology Department, Lille University Medical Center, Lille Cedex, France.

ABSTRACT

Introduction: The selection of task-relevant information requires both the focalization of attention on the task and resistance to interference from irrelevant stimuli. A previous study using the P3 component of the event-related potentials suggested that a reduced ability to resist interference could be responsible for attention disorders at early stages of Parkinson's disease (PD), with a possible role of the dorsolateral prefrontal cortex (DLPFC).

Methods: Our objective was to better determine the origin of this impairment, by studying an earlier ERP component, the N2, and its subcomponents, as they reflect early inhibition processes and as they are known to have sources in the anterior cingulate cortex (ACC), which is involved together with the DLPFC in inhibition processes. Fifteen early-stage PD patients and 15 healthy controls (HCs) performed a three-stimulus visual oddball paradigm, consisting in detecting target inputs amongst standard stimuli, while resisting interference from distracter ones. A 128-channel electroencephalogram was recorded during this task and the generators of the N2 subcomponents were identified using standardized weighted low-resolution electromagnetic tomography (swLORETA).

Results: PD patients displayed fewer N2 generators than HCs in both the DLPFC and the ACC, for all types of stimuli. In contrast to controls, PD patients did not show any differences between their generators for different N2 subcomponents.

Conclusion: Our data suggest that impaired inhibition in PD results from dysfunction of the DLPFC and the ACC during the early stages of attentional processes.

No MeSH data available.


Related in: MedlinePlus

A schematic representation of the three-stimulus visual oddball paradigm.The circle task is on the left and the square task on the right.
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pone.0131654.g001: A schematic representation of the three-stimulus visual oddball paradigm.The circle task is on the left and the square task on the right.

Mentions: Subjects were comfortably seated and watched a 17-inch computer monitor set 150 cm in front of them at head height. Event-related potentials were recorded as the subjects performed a three-stimulus visual oddball task similar to that used by Bledowski et al. [45]. A session included two different task types (a circle task with squares as distracters and a square task with circles as distracters) with 360 stimuli each. The order of the two task types was counterbalanced so that half the participants saw circles first and half saw squares first. Fig 1 depicts the experimental task: the stimuli were solid blue shapes displayed in a semi-random order for 75 ms each. The interstimulus interval varied from 1800 to 2200 ms. The stimuli were defined as standard shapes (40 mm diameter circles or 35 mm sided squares), distracters (a different shape: 35 mm sided squares or 40 mm diameter circles, respectively) or targets (smaller than the standard shape: 33 mm diameter circles or 30 mm sided squares) and were displayed with a probability of 0.84, 0.08, and 0.08, respectively. The subject was told to respond to presentation of a target stimulus by pressing a button with his/her right hand within 2000 ms. Before each task, all subjects had a practice run in the absence of distracter stimuli. The reaction time, omission rate and standard and distracter commission rates were recorded. The omission rate was defined as the number of misses divided by the total number of targets (i.e. 60) x 100. The overall commission rate was defined as the number of false alarms divided by the total number of non-target stimuli (distracter + standard stimuli, i.e. 660) x 100. The distracter commission rate corresponded to the number of false alarms after occurrence of a distracter divided by the total numbers of distracters (i.e. 60) x 100.


Impaired Early Attentional Processes in Parkinson's Disease: A High-Resolution Event-Related Potentials Study.

Bocquillon P, Bourriez JL, Palmero-Soler E, Defebvre L, Derambure P, Dujardin K - PLoS ONE (2015)

A schematic representation of the three-stimulus visual oddball paradigm.The circle task is on the left and the square task on the right.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4489862&req=5

pone.0131654.g001: A schematic representation of the three-stimulus visual oddball paradigm.The circle task is on the left and the square task on the right.
Mentions: Subjects were comfortably seated and watched a 17-inch computer monitor set 150 cm in front of them at head height. Event-related potentials were recorded as the subjects performed a three-stimulus visual oddball task similar to that used by Bledowski et al. [45]. A session included two different task types (a circle task with squares as distracters and a square task with circles as distracters) with 360 stimuli each. The order of the two task types was counterbalanced so that half the participants saw circles first and half saw squares first. Fig 1 depicts the experimental task: the stimuli were solid blue shapes displayed in a semi-random order for 75 ms each. The interstimulus interval varied from 1800 to 2200 ms. The stimuli were defined as standard shapes (40 mm diameter circles or 35 mm sided squares), distracters (a different shape: 35 mm sided squares or 40 mm diameter circles, respectively) or targets (smaller than the standard shape: 33 mm diameter circles or 30 mm sided squares) and were displayed with a probability of 0.84, 0.08, and 0.08, respectively. The subject was told to respond to presentation of a target stimulus by pressing a button with his/her right hand within 2000 ms. Before each task, all subjects had a practice run in the absence of distracter stimuli. The reaction time, omission rate and standard and distracter commission rates were recorded. The omission rate was defined as the number of misses divided by the total number of targets (i.e. 60) x 100. The overall commission rate was defined as the number of false alarms divided by the total number of non-target stimuli (distracter + standard stimuli, i.e. 660) x 100. The distracter commission rate corresponded to the number of false alarms after occurrence of a distracter divided by the total numbers of distracters (i.e. 60) x 100.

Bottom Line: PD patients displayed fewer N2 generators than HCs in both the DLPFC and the ACC, for all types of stimuli.In contrast to controls, PD patients did not show any differences between their generators for different N2 subcomponents.Our data suggest that impaired inhibition in PD results from dysfunction of the DLPFC and the ACC during the early stages of attentional processes.

View Article: PubMed Central - PubMed

Affiliation: Clinical Neurophysiology Department, Lille University Medical Center, Lille Cedex, France.

ABSTRACT

Introduction: The selection of task-relevant information requires both the focalization of attention on the task and resistance to interference from irrelevant stimuli. A previous study using the P3 component of the event-related potentials suggested that a reduced ability to resist interference could be responsible for attention disorders at early stages of Parkinson's disease (PD), with a possible role of the dorsolateral prefrontal cortex (DLPFC).

Methods: Our objective was to better determine the origin of this impairment, by studying an earlier ERP component, the N2, and its subcomponents, as they reflect early inhibition processes and as they are known to have sources in the anterior cingulate cortex (ACC), which is involved together with the DLPFC in inhibition processes. Fifteen early-stage PD patients and 15 healthy controls (HCs) performed a three-stimulus visual oddball paradigm, consisting in detecting target inputs amongst standard stimuli, while resisting interference from distracter ones. A 128-channel electroencephalogram was recorded during this task and the generators of the N2 subcomponents were identified using standardized weighted low-resolution electromagnetic tomography (swLORETA).

Results: PD patients displayed fewer N2 generators than HCs in both the DLPFC and the ACC, for all types of stimuli. In contrast to controls, PD patients did not show any differences between their generators for different N2 subcomponents.

Conclusion: Our data suggest that impaired inhibition in PD results from dysfunction of the DLPFC and the ACC during the early stages of attentional processes.

No MeSH data available.


Related in: MedlinePlus