The decoupling of structural and functional connectivity of auditory networks in individuals at clinical high-risk for psychosis

Figures & data

Figure 1. Study Protocol. DLPFC, PAC and dACC generate the auditory-evoked gamma-band response. CHR: Clinical High-Risk; -NP: Non-Psychosis; -P: Psychosis; dACC: dorsal Anterior Cingulate Cortex; DLPFC: Dorsolateral Prefrontal Cortex; HC: Healthy Controls; PAC: Primary Auditory Cortex.

Figure 2. Clustering results of the (a) AF, (b) CB and (c) SLF-II of a CHR subject. White matter fibre clustering was used to extract tracts for each subject. AF: Arcuate Fasciculus; CB: Cingulum Bundle; CHR: Clinical High-Risk; SLF-II: Superior Longitudinal Fasciculus II.

Table 1. Demographic and clinical characteristics.

Variable	HC (n = 13)	CHR (n = 26)	χ^2/t	p	CHR-NP (n = 15)	CHR-P (n = 7)	χ^2/t	p
Sex (m/f)	9/4	13/13	1.30	.25	7/8	5/2	1.18	.28
Age^†^,a	22.31 ± 4.50	21.08 ± 3.72	0.91	.37	21.33 ± 3.74	20.86 ± 4.38	−0.29	.77
Education^†^,a	14.35 ± 3.02	13.10 ± 3.02	1.22	.23	13.03 ± 2.88	13.79 ± 4.14	−0.50	.63
Handedness^b	1/12	2/24	0.00	1	1/14	1/6	0.34	.56
Antipsychotic Medication^†		n = 9			n = 6	n = 3	0.28	.60
CPZE^c (mg/day)		168.75 ± 148.92			180 ± 172.16	150 ± 132.29	0.26	.81
Duration^d		3.09 ± 3.30			4.38 ± 5.13	2.23 ± 2.42	0.66	.56
PANSS^†^,e
Positive		11.19 ± 2.87			11.20 ± 3.28	11.29 ± 2.50	−0.06	.95
Negative		9.58 ± 2.72			9.47 ± 3.11	10.14 ± 1.95	−0.53	.61
Global		25.27 ± 5.50			26.33 ± 6.41	24.14 ± 4.53	0.81	.43
SOPS^†^,f
Positive		5.58 ± 4.67			4.73 ± 4.54	7.86 ± 3.80	−1.57	.13
Negative		5.83 ± 5.33			5.43 ± 4.88	7.00 ± 6.39	−0.60	.55
Disorganisation		2.28 ± 2.37			1.93 ± 2.12	3.33 ± 3.27	−1.17	.26
Global		4.37 ± 3.29			4.54 ± 3.80	4.00 ± 2.00	0.27	.79

^†Values are M ± SD. CHR: Clinical High-Risk; -NP: Non-Psychosis; -P: Psychosis; HC: Healthy Controls; ^aYears; ^bLeft/Right; ^cChlorpromazine Equivalents; ^dMonths; ^ePositive and Negative Syndrome Scale; ^fScale of Prodromal Symptoms.

Figure 3. FA and LPS compared between CHR subjects and HC. CHR subjects exhibited significantly increased FA in the right AF compared to HC (CHR: .64 ± .02; HC: .61 ± .03; F(1, 34) = 12.41; p < .001, η² = .31). The LPS between right PAC and DLPFC, which are connected by the AF, was decreased in CHR subjects compared to HC (CHR: .69 ± .14; HC: .77 ± .12; F(1, 37) = 3.3; p = .078, η² = .08). AF: Arcuate Fasciculus; CHR: Clinical High-Risk; DLPFC: Dorsolateral Prefrontal Cortex; FA: free-water corrected Fractional Anisotropy; HC: Healthy Controls; LPS: Lagged Phase Synchronisation; PAC: Primary Auditory Cortex.

Table 2. ANCOVAs for group differences in each tract.

FA	CHR	HC	F(1, 34)	p	CHR-NP	CHR-P	F(1, 21)	p
Left AF^†	.63 ± .03	.62 ± .04	2.17	.15	.64 ± .02	.62 ± .02	2.19	.15
Right AF^†	.64 ± .02	.61 ± .03	15.19	< .001*	.64 ± .02	.65 ± .02	0.02	.89
Left CB^†	.51 ± .04	.50 ± .04	2.93	.10	.51 ± .05	.53 ± .05	0.00	.99
Right CB^†	.50 ± .04	.50 ± .02	0.03	.87	.51 ± .03	.51 ± .05	0.17	.68
Left SLF-II^†	.57 ± .03	.56 ± .03	1.68	.20	.57 ± .03	.58 ± .03	0.06	.80
Right SLF-II^†	.60 ± .03	.59 ± .04	0.69	.41	.59 ± .04	.61 ± .03	0.42	.52

^†Values are M ± SD. AF: Arcuate Fasciculus; CB: Cingulum Bundle; CHR: Clinical High-Risk; -NP: Non-Psychosis; -P: Psychosis; FA: free-water corrected Fractional Anisotropy; HC: Healthy Controls; SLF-II: Superior Longitudinal Fasciculus II. *Significant difference after Bonferroni correction with p ≤ .008.

Figure 4. Correlation of functional and structural connectivity measures. In HC, the FA of the right AF was positively correlated with the LPS between the respective regions, right PAC and DLPFC. This correlation was absent in CHR individuals. AF: Arcuate Fasciculus; CHR: Clinical High-Risk; DLPFC: Dorsolateral Prefrontal Cortex; FA: free-water corrected Fractional Anisotropy; HC: Healthy Controls; LPS: Lagged Phase Synchronisation; PAC: Primary Auditory Cortex.