*2.4.1.3 Moderators*

*Ethnicity.* It was seen as a dichotomous variable and coded as Latino = 1 and non-Latino = 0.

#### *2.4.1.4 Confounders*

*Age*. It was seen as a continuous variable and was reported by the parents as months.

*Sex.* It was considered as a categorical variable with 0 for girls and 1 for boys.

*Race*. Race was reported by the parent. It was considered as a moderator and was treated as a nominal variable: Black, Asian, Other/Mixed, and White (reference group).

*Family structure.* It was a dichotomous variable self-reported by the parent interviewed and coded 1 vs. 0 for married and unmarried or other condition, respectively.

#### **2.5 Data analysis**

We used the Data Exploration and Analysis Portal (DEAP), a user-friendly online platform for multivariable analysis of the ABCD data. For multivariable analyses, two mixed-effects regression models were estimated (Supplementary Table). *Model 1* tested the additive effects of parental education, ethnicity, and covariates, without interaction terms. *Model 2* also included interaction between parental education and ethnicity on functional connectivity (FC) between the NAcc and FPN. Moreover, we checked the normal distribution of our outcome (Appendix). In all models, the NAcc resting-state functional connectivity with FPN was the outcome. Similar models were performed for the right and left NAcc as well. In total, we ran four models. Also, regression coefficient (b), standard error (SE), and *p*-value were reported.

#### **2.6 Ethical aspect**

The original ABCD research protocol received Institutional Review Board (IRB) approval in several institutions, including the University of California, San Diego (UCSD). Additionally, we received the ABCD data through an agreement between Charles R. Drew University and NIH/NDA. As the ABCD data were fully deidentified, our study was considered to be a nonhuman subject research. This exempted our study from a full review. Besides, all children in the ABCD study provided verbal assent to the protocol approved by the IRB, and all parents/caregivers signed the written informed consent form [80].

#### **3. Result**

#### **3.1 Sample descriptive data**

The present study used data from a large sample of 10,840 preadolescents between 9 and 10 years old (*MAge* = 119 months, SD = 7.5, 5194 females). Most participants (n = 8690; 80.2%) were non-Latino and 2150 (19.8%) were Latino. In terms of race, the study included 7071 White, 1654 Black, 256 Asian American, and 1859 other/mixed race. Latino children showed lower parental education in comparison to non-Latino children (**Table 1**).

The fit of the mixed-effects regression model is summarized in **Table 2**. Models with the interaction effects between parental education and ethnicity showed a better fit when compared with main effect models that only included ethnicity and parental education. This shows that interaction between parental education and ethnicity contributes more to explaining the variance of the outcome for both the right and left NAcc with FPN connectivity.

### **3.2 Right**

#### *3.2.1 Main effect model*

As shown by **Table 3** and **Figure 1**, parental education showed a positive association with the functional connectivity between the right and left NAcc with FPN.


#### **Table 1.**

*Descriptive characteristics overall and by ethnicity (n = 10,840).*

*Parental Education, Ethnicity, and Functional Connectivity between Nucleus Accumbens… DOI: http://dx.doi.org/10.5772/intechopen.101335*


#### **Table 2.**

*Effect sizes and % variance explained by models.*


*Notes: Source: ABCD Study; Mixed-effects regression model is used; all covariates such as race, ethnicity, age, sex, family, and site were controlled.*

*#* p *< 0.1.*

*\**p *< 0.05.*

*\*\**p *< 0.01.*

#### **Table 3.**

*Mixed-effects regressions on the effects of parental education and ethnicity on the functional connectivity between the frontoparietal network and nucleus accumbens (right).*

This positive correlation suggests that children with higher parental education have a stronger rsFC between the right NAcc and FPN.

#### *Parenting - Challenges of Child Rearing in a Changing Society*

#### **Figure 1.**

*Association between parental education and functional connectivity between the right NAcc and FPN overall and by ethnicity.*

#### *3.2.2 Interactive effects model*

**Table 4** and **Figure 1** show that parental education had a stronger positive association between parental education and the right FPN resting-state functional connectivity in Hispanic children than non-Hispanic children.

#### **3.3 Left**

#### *3.3.1 Main effects model*

As shown by **Table 4** and **Figure 2**, parental education showed a positive association with the functional connectivity between the right and left NAcc with FPN. This positive correlation suggests that children with higher parental education have stronger rsFC between left NAcc and FPN.

#### *3.3.2 Interactive effects model*

**Table 4** and **Figure 2** show that parental education had a negative interaction with ethnicity on the functional connectivity between the FPN and the left NAcc. This interaction was indicative of a weaker positive association between parental education and the left FPN-NAcc resting-state functional connectivity in Hispanic children than non-Hispanic children.

#### **4. Discussion**

Our first aim showed a positive correlation between parental education and the NAcc resting-state functional connectivity with the FPN. Our second aim showed ethnic variation in the association between parental education and the right and left NAcc resting-state functional connectivity with the FPN. That is laterality,


**Table 4.** *Mixed-effectsregressionsontheeffectsofparentaleducationandethnicityonthefunctionalconnectivitybetweenthefrontoparietalnetworkandnucleusaccumbens(left).*

*\*\**p *< 0.01.*

*\*\*\**p *< 0.001.*
