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Granger causality analysis reveals distinct spatio-temporal connectivity patterns in motor and perceptual visuo-spatial working memory.

Protopapa F, Siettos CI, Evdokimidis I, Smyrnis N - Front Comput Neurosci (2014)

Bottom Line: We employed spectral Granger causality analysis on a full set of 56 electroencephalographic recordings acquired during the execution of either a 2D movement pointing or a perceptual (yes/no) change detection task with memory and non-memory conditions.On the basis of network characteristics across frequency bands, we provide evidence for the full dissociation of the corresponding cognitive processes.Our results favor the hypothesis which considers spatial working memory as a by-product of specific mental processes that engages common brain areas under different network organizations.

View Article: PubMed Central - PubMed

Affiliation: School of Applied Mathematics and Physical Sciences, National Technical University of Athens Athens, Greece.

ABSTRACT
We employed spectral Granger causality analysis on a full set of 56 electroencephalographic recordings acquired during the execution of either a 2D movement pointing or a perceptual (yes/no) change detection task with memory and non-memory conditions. On the basis of network characteristics across frequency bands, we provide evidence for the full dissociation of the corresponding cognitive processes. Movement-memory trial types exhibited higher degree nodes during the first 2 s of the delay period, mainly at central, left frontal and right-parietal areas. Change detection-memory trial types resulted in a three-peak temporal pattern of the total degree with higher degree nodes emerging mainly at central, right frontal, and occipital areas. Functional connectivity networks resulting from non-memory trial types were characterized by more sparse structures for both tasks. The movement-memory trial types encompassed an apparent coarse flow from frontal to parietal areas while the opposite flow from occipital, parietal to central and frontal areas was evident for the change detection-memory trial types. The differences among tasks and conditions were more profound in α (8-12 Hz) and β (12-30 Hz) and less in γ (30-45 Hz) band. Our results favor the hypothesis which considers spatial working memory as a by-product of specific mental processes that engages common brain areas under different network organizations.

No MeSH data available.


Related in: MedlinePlus

γ band (30–45 Hz). Top: Temporal evolution of the total degree of the networks whose connections represent statistically significant differences in the GC distributions for each pair of electrodes, across four planned comparisons, namely, M-M vs. M-NM, CD-M vs. CD-NM, M-M vs. CD-M and M-NM vs. CD-NM trial types. Four characteristic time intervals are marked with gray bars (1: [0.5, 0.75] s, 2: [0.9, 1.15] s, 3: [1.25, 1.5] s, 4: [2, 2.25] s). Bottom: Topographic maps of node degrees of the statistically different networks resulted from the four planned comparisons, within each one of the characteristic time intervals.
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Figure 7: γ band (30–45 Hz). Top: Temporal evolution of the total degree of the networks whose connections represent statistically significant differences in the GC distributions for each pair of electrodes, across four planned comparisons, namely, M-M vs. M-NM, CD-M vs. CD-NM, M-M vs. CD-M and M-NM vs. CD-NM trial types. Four characteristic time intervals are marked with gray bars (1: [0.5, 0.75] s, 2: [0.9, 1.15] s, 3: [1.25, 1.5] s, 4: [2, 2.25] s). Bottom: Topographic maps of node degrees of the statistically different networks resulted from the four planned comparisons, within each one of the characteristic time intervals.

Mentions: Quantitatively, compared to the lower frequency bands (δ and θ, Figures 3, 4), the differences in the networks were larger in α (Figure 5) and profoundly in β (Figure 6) band. At γ band, no profound differences were observed (Figure 7).


Granger causality analysis reveals distinct spatio-temporal connectivity patterns in motor and perceptual visuo-spatial working memory.

Protopapa F, Siettos CI, Evdokimidis I, Smyrnis N - Front Comput Neurosci (2014)

γ band (30–45 Hz). Top: Temporal evolution of the total degree of the networks whose connections represent statistically significant differences in the GC distributions for each pair of electrodes, across four planned comparisons, namely, M-M vs. M-NM, CD-M vs. CD-NM, M-M vs. CD-M and M-NM vs. CD-NM trial types. Four characteristic time intervals are marked with gray bars (1: [0.5, 0.75] s, 2: [0.9, 1.15] s, 3: [1.25, 1.5] s, 4: [2, 2.25] s). Bottom: Topographic maps of node degrees of the statistically different networks resulted from the four planned comparisons, within each one of the characteristic time intervals.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4230052&req=5

Figure 7: γ band (30–45 Hz). Top: Temporal evolution of the total degree of the networks whose connections represent statistically significant differences in the GC distributions for each pair of electrodes, across four planned comparisons, namely, M-M vs. M-NM, CD-M vs. CD-NM, M-M vs. CD-M and M-NM vs. CD-NM trial types. Four characteristic time intervals are marked with gray bars (1: [0.5, 0.75] s, 2: [0.9, 1.15] s, 3: [1.25, 1.5] s, 4: [2, 2.25] s). Bottom: Topographic maps of node degrees of the statistically different networks resulted from the four planned comparisons, within each one of the characteristic time intervals.
Mentions: Quantitatively, compared to the lower frequency bands (δ and θ, Figures 3, 4), the differences in the networks were larger in α (Figure 5) and profoundly in β (Figure 6) band. At γ band, no profound differences were observed (Figure 7).

Bottom Line: We employed spectral Granger causality analysis on a full set of 56 electroencephalographic recordings acquired during the execution of either a 2D movement pointing or a perceptual (yes/no) change detection task with memory and non-memory conditions.On the basis of network characteristics across frequency bands, we provide evidence for the full dissociation of the corresponding cognitive processes.Our results favor the hypothesis which considers spatial working memory as a by-product of specific mental processes that engages common brain areas under different network organizations.

View Article: PubMed Central - PubMed

Affiliation: School of Applied Mathematics and Physical Sciences, National Technical University of Athens Athens, Greece.

ABSTRACT
We employed spectral Granger causality analysis on a full set of 56 electroencephalographic recordings acquired during the execution of either a 2D movement pointing or a perceptual (yes/no) change detection task with memory and non-memory conditions. On the basis of network characteristics across frequency bands, we provide evidence for the full dissociation of the corresponding cognitive processes. Movement-memory trial types exhibited higher degree nodes during the first 2 s of the delay period, mainly at central, left frontal and right-parietal areas. Change detection-memory trial types resulted in a three-peak temporal pattern of the total degree with higher degree nodes emerging mainly at central, right frontal, and occipital areas. Functional connectivity networks resulting from non-memory trial types were characterized by more sparse structures for both tasks. The movement-memory trial types encompassed an apparent coarse flow from frontal to parietal areas while the opposite flow from occipital, parietal to central and frontal areas was evident for the change detection-memory trial types. The differences among tasks and conditions were more profound in α (8-12 Hz) and β (12-30 Hz) and less in γ (30-45 Hz) band. Our results favor the hypothesis which considers spatial working memory as a by-product of specific mental processes that engages common brain areas under different network organizations.

No MeSH data available.


Related in: MedlinePlus