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Electrophysiological Correlates of Subitizing in Healthy Aging.

Pagano S, Fait E, Monti A, Brignani D, Mazza V - PLoS ONE (2015)

Bottom Line: ERP results in old participants showed a suppression of N2pc amplitudes for all numerosities, and a decrease in CDA only for the largest set (4-6 targets).In contrast with the pattern for young adults, time/frequency results on older adults revealed neither a modulation of alpha oscillations as a function of target numerosity, nor an effect of ERD lateralization.These patterns indicate that both attention and working memory contribute to the age-related decline in enumeration, and point to an overall decrease in the activity of the visual areas responsible for the processing of the hemifield where the relevant objects are presented.

View Article: PubMed Central - PubMed

Affiliation: Center for Mind/Brain Sciences (CIMeC), University of Trento, Trento, Italy.

ABSTRACT
To understand the nature of age-related changes in enumeration abilities we measured two ERP responses -N2pc and CDA, associated respectively to attentive individuation and VWM- and posterior alpha band (8-15 Hz) event-related desynchronization (ERD), traditionally linked to enhanced target processing. Two groups of old and young participants enumerated a variable number (1-6) of targets presented among distractors. Older participants were less accurate in enumerating targets. ERP results in old participants showed a suppression of N2pc amplitudes for all numerosities, and a decrease in CDA only for the largest set (4-6 targets). In contrast with the pattern for young adults, time/frequency results on older adults revealed neither a modulation of alpha oscillations as a function of target numerosity, nor an effect of ERD lateralization. These patterns indicate that both attention and working memory contribute to the age-related decline in enumeration, and point to an overall decrease in the activity of the visual areas responsible for the processing of the hemifield where the relevant objects are presented.

No MeSH data available.


Related in: MedlinePlus

Time/frequency analysis results.(A) Left: Time-frequency plots for the old and young group averaged across numerosities and side at PO7/8. The white dotted squares indicate the time-frequency bins used to analyze ERS/ERD in the alpha band. Right: Topographical maps of the alpha band in the 300–600 ms post-stimulus window plotted separately for the old and young group and collapsed across numerosities. Contralateral side is plotted on the left. (B) Posterior (PO7/8) ipsilateral and contralateral ERS/ERD time course averaged across numerosities in the old and young group in the alpha band. The young group shows a significant alpha lateralization effect starting around 300 ms post stimulus. (C) Mean alpha ERD as a function of numerosity, laterality and age in the 300–600 time window.
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pone.0131063.g003: Time/frequency analysis results.(A) Left: Time-frequency plots for the old and young group averaged across numerosities and side at PO7/8. The white dotted squares indicate the time-frequency bins used to analyze ERS/ERD in the alpha band. Right: Topographical maps of the alpha band in the 300–600 ms post-stimulus window plotted separately for the old and young group and collapsed across numerosities. Contralateral side is plotted on the left. (B) Posterior (PO7/8) ipsilateral and contralateral ERS/ERD time course averaged across numerosities in the old and young group in the alpha band. The young group shows a significant alpha lateralization effect starting around 300 ms post stimulus. (C) Mean alpha ERD as a function of numerosity, laterality and age in the 300–600 time window.

Mentions: The results of the ANOVA on ERS/ERD using time, group, numerosity and laterality as factors showed significant effects of laterality, F(1,34) = 4.2, p <.05, time, F(1,34) = 92.6, p <.001, time X laterality F(1,34) = 4.1, p <.05, group X numerosity X time F(5,170) = 3.6, p <.01, and group X numerosity X time X laterality, F(5,170) = 2.2, p <.05. Separate ANOVAs were conducted separately for each time range. The ANOVA for the 0–300 ms time window showed no significant effects (all ps>.13). The ANOVA in the 300–600 ms time window indicated significant effects of laterality F(1,34) = 5,4, p <.05, group X numerosity F(5,170) = 2.4, p <.01, group X laterality F(1,34) = 3.4, p <.05, and group X laterality X numerosity, F(5,170) = 3.7, p <.01. Follow-up ANOVAs were conducted separately for each group. In the young group we found a significant main effect of laterality F(1,17) = 7.9, p <.01 and a significant interaction between laterality and numerosity F(5,85) = 2.6, p <.05. There was a significant effect of numerosity F(5,85) = 3.3, p <.01 with a significant linear trend F(1,17) = 11.1, p <.01 for the contralateral electrodes. No significant effect of numerosity was present for the ipsilateral electrodes (F<1, p = .56). Taken together, these results indicate a larger decrease in alpha power for contralateral than ipsilateral electrodes in young adults, and that this lateralized decrease was monotonically modulated by numerosity (see Fig 3). In contrast, no significant effects emerged for the old group (all ps>.10).


Electrophysiological Correlates of Subitizing in Healthy Aging.

Pagano S, Fait E, Monti A, Brignani D, Mazza V - PLoS ONE (2015)

Time/frequency analysis results.(A) Left: Time-frequency plots for the old and young group averaged across numerosities and side at PO7/8. The white dotted squares indicate the time-frequency bins used to analyze ERS/ERD in the alpha band. Right: Topographical maps of the alpha band in the 300–600 ms post-stimulus window plotted separately for the old and young group and collapsed across numerosities. Contralateral side is plotted on the left. (B) Posterior (PO7/8) ipsilateral and contralateral ERS/ERD time course averaged across numerosities in the old and young group in the alpha band. The young group shows a significant alpha lateralization effect starting around 300 ms post stimulus. (C) Mean alpha ERD as a function of numerosity, laterality and age in the 300–600 time window.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4476746&req=5

pone.0131063.g003: Time/frequency analysis results.(A) Left: Time-frequency plots for the old and young group averaged across numerosities and side at PO7/8. The white dotted squares indicate the time-frequency bins used to analyze ERS/ERD in the alpha band. Right: Topographical maps of the alpha band in the 300–600 ms post-stimulus window plotted separately for the old and young group and collapsed across numerosities. Contralateral side is plotted on the left. (B) Posterior (PO7/8) ipsilateral and contralateral ERS/ERD time course averaged across numerosities in the old and young group in the alpha band. The young group shows a significant alpha lateralization effect starting around 300 ms post stimulus. (C) Mean alpha ERD as a function of numerosity, laterality and age in the 300–600 time window.
Mentions: The results of the ANOVA on ERS/ERD using time, group, numerosity and laterality as factors showed significant effects of laterality, F(1,34) = 4.2, p <.05, time, F(1,34) = 92.6, p <.001, time X laterality F(1,34) = 4.1, p <.05, group X numerosity X time F(5,170) = 3.6, p <.01, and group X numerosity X time X laterality, F(5,170) = 2.2, p <.05. Separate ANOVAs were conducted separately for each time range. The ANOVA for the 0–300 ms time window showed no significant effects (all ps>.13). The ANOVA in the 300–600 ms time window indicated significant effects of laterality F(1,34) = 5,4, p <.05, group X numerosity F(5,170) = 2.4, p <.01, group X laterality F(1,34) = 3.4, p <.05, and group X laterality X numerosity, F(5,170) = 3.7, p <.01. Follow-up ANOVAs were conducted separately for each group. In the young group we found a significant main effect of laterality F(1,17) = 7.9, p <.01 and a significant interaction between laterality and numerosity F(5,85) = 2.6, p <.05. There was a significant effect of numerosity F(5,85) = 3.3, p <.01 with a significant linear trend F(1,17) = 11.1, p <.01 for the contralateral electrodes. No significant effect of numerosity was present for the ipsilateral electrodes (F<1, p = .56). Taken together, these results indicate a larger decrease in alpha power for contralateral than ipsilateral electrodes in young adults, and that this lateralized decrease was monotonically modulated by numerosity (see Fig 3). In contrast, no significant effects emerged for the old group (all ps>.10).

Bottom Line: ERP results in old participants showed a suppression of N2pc amplitudes for all numerosities, and a decrease in CDA only for the largest set (4-6 targets).In contrast with the pattern for young adults, time/frequency results on older adults revealed neither a modulation of alpha oscillations as a function of target numerosity, nor an effect of ERD lateralization.These patterns indicate that both attention and working memory contribute to the age-related decline in enumeration, and point to an overall decrease in the activity of the visual areas responsible for the processing of the hemifield where the relevant objects are presented.

View Article: PubMed Central - PubMed

Affiliation: Center for Mind/Brain Sciences (CIMeC), University of Trento, Trento, Italy.

ABSTRACT
To understand the nature of age-related changes in enumeration abilities we measured two ERP responses -N2pc and CDA, associated respectively to attentive individuation and VWM- and posterior alpha band (8-15 Hz) event-related desynchronization (ERD), traditionally linked to enhanced target processing. Two groups of old and young participants enumerated a variable number (1-6) of targets presented among distractors. Older participants were less accurate in enumerating targets. ERP results in old participants showed a suppression of N2pc amplitudes for all numerosities, and a decrease in CDA only for the largest set (4-6 targets). In contrast with the pattern for young adults, time/frequency results on older adults revealed neither a modulation of alpha oscillations as a function of target numerosity, nor an effect of ERD lateralization. These patterns indicate that both attention and working memory contribute to the age-related decline in enumeration, and point to an overall decrease in the activity of the visual areas responsible for the processing of the hemifield where the relevant objects are presented.

No MeSH data available.


Related in: MedlinePlus