Effects of verbal working memory load on corticocortical connectivity modeled by path analysis of functional magnetic resonance imaging data

TY - JOUR

T1 - Effects of verbal working memory load on corticocortical connectivity modeled by path analysis of functional magnetic resonance imaging data

AU - Honey, G. D.

AU - Fu, C. H. Y.

AU - Kim, J.

AU - Brammer, M. J.

AU - Croudace, T. J.

AU - Suckling, J.

AU - Pich, E. M.

AU - Williams, S. C. R.

AU - Bullmore, E. T.

N1 - M1 - Article

PY - 2002/10

Y1 - 2002/10

N2 - We investigated the hypothesis that there are load-related changes in the integrated function of frontoparietal working memory networks. Functional magnetic resonance imaging time-series data from 10 healthy volunteers performing a graded n-back verbal working memory task were modeled using path analysis. Seven generically activated regions were included in the model: left/right middle frontal gyri (L/R MFG), left/right inferior frontal gyri (L/R IFG), left/right posterior parietal cortex (L/R PPC), and supplementary motor area (SMA). The model provided a good fit to the 1-back (χ2 = 7.04, df = 8, P = 0.53) and 2-back conditions (χ2 = 9.35, df = 8, P = 0.31) but not for the 3-back condition (χ2 = 20.60, df = 8, P = 0.008). Model parameter estimates were compared overall among conditions: there was a significant difference overall between 1-back and 2-back conditions (χ2diff = 74.77, df = 20, P <0.001) and also between 2-back and 3-back conditions (χ2diff = 96.28, df = 20, P <0.001). Path coefficients between LIFG and LPPC were significantly different from zero in both 1-back and 2-back conditions; in the 2-back condition, additional paths from LIFG to LPPC via SMA and to RMFG from LMFG and LPPC were also nonzero. This study demonstrated a significant change in functional integration of a neurocognitive network for working memory as a correlate of increased load. Enhanced inferior frontoparietal and prefrontoprefrontal connectivity was observed as a correlate of increasing memory load, which may reflect greater demand for maintenance and executive processes, respectively.

AB - We investigated the hypothesis that there are load-related changes in the integrated function of frontoparietal working memory networks. Functional magnetic resonance imaging time-series data from 10 healthy volunteers performing a graded n-back verbal working memory task were modeled using path analysis. Seven generically activated regions were included in the model: left/right middle frontal gyri (L/R MFG), left/right inferior frontal gyri (L/R IFG), left/right posterior parietal cortex (L/R PPC), and supplementary motor area (SMA). The model provided a good fit to the 1-back (χ2 = 7.04, df = 8, P = 0.53) and 2-back conditions (χ2 = 9.35, df = 8, P = 0.31) but not for the 3-back condition (χ2 = 20.60, df = 8, P = 0.008). Model parameter estimates were compared overall among conditions: there was a significant difference overall between 1-back and 2-back conditions (χ2diff = 74.77, df = 20, P <0.001) and also between 2-back and 3-back conditions (χ2diff = 96.28, df = 20, P <0.001). Path coefficients between LIFG and LPPC were significantly different from zero in both 1-back and 2-back conditions; in the 2-back condition, additional paths from LIFG to LPPC via SMA and to RMFG from LMFG and LPPC were also nonzero. This study demonstrated a significant change in functional integration of a neurocognitive network for working memory as a correlate of increased load. Enhanced inferior frontoparietal and prefrontoprefrontal connectivity was observed as a correlate of increasing memory load, which may reflect greater demand for maintenance and executive processes, respectively.

UR - https://www.scopus.com/pages/publications/0036428319

U2 - 10.1006/nimg.2002.1193

DO - 10.1006/nimg.2002.1193

M3 - Article

SN - 1053-8119

VL - 17

SP - 573

EP - 582

JO - NeuroImage

JF - NeuroImage

IS - 2

ER -