Table 2.
(a) Summary of the ABFs and the PERs for the pairwise model comparison. (b) Behavioural data as recorded during the fMRI experiment. (There was a significant (F3,76=16.91; p<0.05) difference in the word production rate between the four fluency conditions (given as mean±s.d.).) (c) Overview of the coupling parameters obtained from fitting the dynamic causal models to the empirical fMRI data. (The shown values represent the mean±s.d. across subjects.)
| (a) Bayesian model comparison results | ||||||
| 1 versus 2 | 1 versus 3 | 1 versus 4 | 2 versus 3 | 2 versus 4 | 3 versus 4 | |
| ABF | 113,372565 | 1005,67775 | 194,488871 | 605,4330648 | 100,0601845 | 0,20815038 |
| PER | 11 : 1 | 19 : 0 | 19 : 0 | 18 : 1 | 18 : 2 | 3 : 16 |
| (b) behavioural measurements | ||||||
| average number of words produced | ||||||
| semantic | syntactic | phonological | free | |||
| 48.65±5.77 | 42.7±8.07 | 46.7±7.52 | 56.85±3.6 | |||
| (c) coupling parameters | ||||||
| driving input into BA 44 by context (condition) | ||||||
| semantic | syntactic | phonological | free | |||
| 0.56±0.41 | 0.61±0.56 | 0.58±0.44 | 0.52±0.38 | |||
| intrinsic (context-independent) coupling | ||||||
| BA 44→insula | insula→caudate | insula→cerebellum | caudate→PMC | cerebellum→PMC | PMC→M1 | |
| 0.64±0.35 | 0.61±0.25 | 0.56±0.19 | 0.47±0.23 | 0.46±0.21 | 0.56±0.17 | |
| modulatory effects of verbal fluency | ||||||
| BA 44→ insula | insula→caudate | insula→cerebellum | caudate→PMC | cerebellum→PMC | PMC→M1 | |
| 0.148±0.10 | 0.149±0.08 | 0.138±0.08 | 0.120±0.07 | 0.117±0.06 | 0.139±0.06 | |