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Richness in Functional Connectivity Depends on the Neuronal Integrity within the Posterior Cingulate Cortex

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ABSTRACT

The brain's connectivity skeleton—a rich club of strongly interconnected members—was initially shown to exist in human structural networks, but recent evidence suggests a functional counterpart. This rich club typically includes key regions (or hubs) from multiple canonical networks, reducing the cost of inter-network communication. The posterior cingulate cortex (PCC), a hub node embedded within the default mode network, is known to facilitate communication between brain networks and is a key member of the “rich club.” Here, we assessed how metabolic signatures of neuronal integrity and cortical thickness influence the global extent of a functional rich club as measured using the functional rich club coefficient (fRCC). Rich club estimation was performed on functional connectivity of resting state brain signals acquired at 3T in 48 healthy adult subjects. Magnetic resonance spectroscopy was measured in the same session using a point resolved spectroscopy sequence. We confirmed convergence of functional rich club with a previously established structural rich club. N-acetyl aspartate (NAA) in the PCC is significantly correlated with age (p = 0.001), while the rich club coefficient showed no effect of age (p = 0.106). In addition, we found a significant quadratic relationship between fRCC and NAA concentration in PCC (p = 0.009). Furthermore, cortical thinning in the PCC was correlated with a reduced rich club coefficient after accounting for age and NAA. In conclusion, we found that the fRCC is related to a marker of neuronal integrity in a key region of the cingulate cortex. Furthermore, cortical thinning in the same area was observed, suggesting that both cortical thinning and neuronal integrity in the hub regions influence functional integration of at a whole brain level.

No MeSH data available.


Partial correlation between the rich club coefficient and mean cortical thickness in the PCC (r = 0.339, p = 0.015, t = 2.519).
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Figure 6: Partial correlation between the rich club coefficient and mean cortical thickness in the PCC (r = 0.339, p = 0.015, t = 2.519).

Mentions: Cortical thickness in the PCC positively correlated with the rich club coefficient after accounting for age and NAA/Cr as covariates (Figure 5, FDR corrected). Although extensive parts of the cortex showed reduced CT as a factor of age (Figure S5), this did not overlap with the previous finding. CT was also positively correlated with NAA/Cr, predominantly in the mid cingulate cortex, but did not overlap with the fRCC correlation with CT in the PCC (Figure S6). After accounting for age as a covariate, fRCC and mean CTh in the PCC was positively correlated (r = 0.339, p = 0.015, t = 2.519, Figure 6). When considering only age as a covariate, a cluster of vertices in the same location is observed at an uncorrected threshold only (Figure S7).


Richness in Functional Connectivity Depends on the Neuronal Integrity within the Posterior Cingulate Cortex
Partial correlation between the rich club coefficient and mean cortical thickness in the PCC (r = 0.339, p = 0.015, t = 2.519).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384321&req=5

Figure 6: Partial correlation between the rich club coefficient and mean cortical thickness in the PCC (r = 0.339, p = 0.015, t = 2.519).
Mentions: Cortical thickness in the PCC positively correlated with the rich club coefficient after accounting for age and NAA/Cr as covariates (Figure 5, FDR corrected). Although extensive parts of the cortex showed reduced CT as a factor of age (Figure S5), this did not overlap with the previous finding. CT was also positively correlated with NAA/Cr, predominantly in the mid cingulate cortex, but did not overlap with the fRCC correlation with CT in the PCC (Figure S6). After accounting for age as a covariate, fRCC and mean CTh in the PCC was positively correlated (r = 0.339, p = 0.015, t = 2.519, Figure 6). When considering only age as a covariate, a cluster of vertices in the same location is observed at an uncorrected threshold only (Figure S7).

View Article: PubMed Central - PubMed

ABSTRACT

The brain's connectivity skeleton—a rich club of strongly interconnected members—was initially shown to exist in human structural networks, but recent evidence suggests a functional counterpart. This rich club typically includes key regions (or hubs) from multiple canonical networks, reducing the cost of inter-network communication. The posterior cingulate cortex (PCC), a hub node embedded within the default mode network, is known to facilitate communication between brain networks and is a key member of the “rich club.” Here, we assessed how metabolic signatures of neuronal integrity and cortical thickness influence the global extent of a functional rich club as measured using the functional rich club coefficient (fRCC). Rich club estimation was performed on functional connectivity of resting state brain signals acquired at 3T in 48 healthy adult subjects. Magnetic resonance spectroscopy was measured in the same session using a point resolved spectroscopy sequence. We confirmed convergence of functional rich club with a previously established structural rich club. N-acetyl aspartate (NAA) in the PCC is significantly correlated with age (p = 0.001), while the rich club coefficient showed no effect of age (p = 0.106). In addition, we found a significant quadratic relationship between fRCC and NAA concentration in PCC (p = 0.009). Furthermore, cortical thinning in the PCC was correlated with a reduced rich club coefficient after accounting for age and NAA. In conclusion, we found that the fRCC is related to a marker of neuronal integrity in a key region of the cingulate cortex. Furthermore, cortical thinning in the same area was observed, suggesting that both cortical thinning and neuronal integrity in the hub regions influence functional integration of at a whole brain level.

No MeSH data available.