Cognitive demand modulates connectivity patterns of rostral inferior parietal cortex in cognitive control of language

Figures & data

Figure 1. Right and superior display of the IPC division to rostral (yellow-red), middle (cyan), and caudal (violet) parts

Table 1. Details of the participants included in the analysis

number of participants	male	female	average age	L2 proficiency level	means of measurement	mean score	SD
45	11	34	21.7	upper intermediate	placement test	44.17/60	2.23

Table 2. Summary of each variable that the stimuli were matched on in L1 & L2 with t-test statistics

Name of variable*	Mean L1	Mean L2	SD L1	SD L2	t	P Value
Number of letters	4.71	4.67	1.43	1.21	0.154	0.878
Number of syllables	1.3	1.33	0.46	0.52	−0.42	0.678
RT (mean)	885.51	849.04	93.81	102.39	1.82	0.072
H statistics	0.23	0.22	1.86	3.28	1.33	0.894
Initial fricative	0.1	0.06	0.31	0.245	7.33	0.465

*For a detailed description on the identification of variables see: https://crl.ucsd.edu/experiments/ipnp/method/getdata/uspnovariables.html

**.

Figure 2. L1 and L2 RTs in millisecond in the switch and non-switch contexts in both the by-participants and the by-item analyses. As shown in this figure, in both switch and non-switch contexts L2 lexical production is quicker than L1 lexical production, with symmetrical switch costs. The error bars represent SEs

Figure 3. Showing clusters with positive and negative functional association with the right IPC rostral cluster as a result of switching to L1. In this figure, the location of the right IPC rostral cluster, as the seed region, is shown in yellow-red. Clusters with negative functional associations with the seed region, localized in the precuneus cortex and the postcentral gyrus are shown in green. A cluster localized in the cerebellum, posterior lobe, declive with positive functional association with the seed region is displayed in blue

Table 3. Clusters exhibiting functional connectivity with the rostral IPC R/L seed as a result of switching to L1/L2

						Location (MNI)
Clusters	Switch L1/L2	Voxels	Coupling	Z-Max	R/L Seed	X	Y	Z
Cerebellum, posterior lobe	L1	125	Positive	4.19	R	15.8,	−60.8,	−20.4
Postcentral gyrus	L1	147	Negative	4.13	R	20.5,	−34.6,	76.5
Precuneus cortex	L1	254	Negative	5.18	R	15.8,	−55.1,	17.7
Superior frontal gyrusnegative	L1	120	Negative	4.05	L	2.44,	38.2,	48.3
Precuneus cortex	L1	475	Negative	4.6	L	4.28,	−48.1,	39.9
Cingulate gyrus, anterior division	L2	99	Positive	3.91	R	−2.01,	9.28,	40.7
Precentral gyrus	L2	118	Positive	4.3	R	−39.5,	−4.15,	63.7

Figure 4. Showing clusters with negative functional association with the left IPC rostral cluster as a result of switching to L1. In this figure, the location of the left IPC rostral cluster, as the seed region, is shown in yellow-red. Clusters with negative functional associations with the seed region, localized in the precuneus cortex and the superior frontal gyrus are shown in green

Figure 5. Showing clusters with positive functional association with the right IPC rostral cluster as a result of switching to L2. In this figure, the location of the right IPC rostral cluster, as the seed region, is shown in yellow-red. Clusters with positive functional associations with the seed region, localized in the cingulate gyrus anterior division, and localized in the precentral gyrus are shown in blue

Table

Name of variable**	Mean Set A	Mean Set B	SD Set A	SD Set B	t	P Value
Number of letters	4.71	4.71	1.27	1.6	0.00	1.00
Number of syllables	1.25	1.33	0.44	0.48	−0.62	0.54
RT (mean)	885.86	885.16	87.45	101.67	0.024	0.981
H statistics	0.23	0.23	0.17	0.2	0.004	0.997
Initial fricative	0.08	0.13	0.28	0.34	−0.44	0.664
Word frequency	1.5	1.6	0.54	0.63	−0.631	0.534
Visual complexity	17521.63	16,857.21	7320.9	8299.79	0.27	0.79
Conceptual complexity	1.17	1.25	0.48	0.61	−0.492	0.627
Word complexity	0.00	0.00	0.00	0.00	***	***

*Set A and set B refer to the two sets of twenty-four stimuli.

**Visual complexity and conceptual complexity were matched on set A and B with respect to characteristics of the images and independent of L1.

***These values could not be computed because the standard deviations of both groups are 0.

Table

Name of variable*	Mean Set A	Mean Set B	SD Set A	SD Set B	t	P Value
Number of letters	4.75	4.58	1.33	1.1	0.59	0.57
Number of syllables	1.38	1.3	0.58	0.46	0.62	0.54
RT (mean)	854.5	843.58	87.73	116.88	0.36	0.73
H statistics	0.27	0.18	0.4	0.23	0.93	0.36
Initial fricative	0.08	0.04	0.28	0.2	0.57	0.58
Word frequency	3.73	3.82	1.11	1.2	−0.24	0.81
Visual complexity	17,521.63	16,857.21	7320.9	8299.79	0.27	0.79
Conceptual complexity	1.17	1.25	0.48	0.61	−0.492	0.627
Word complexity	0.00	0.00	0.00	0.00	***	***

*Visual complexity and conceptual complexity were matched on set A and B with respect to characteristics of the images and independent of L2.

** These values could not be computed because the standard deviations of both groups are 0.