On the Spectrum

From Chronnectivity To Chronnectopathy: Connectivity Dynamics of Typical Development
Statistical Analyses
Statistical analyses were carried out in Matlab (version R2011b) using the statistics toolbox
and linear model class. Multiple linear regression was used to examine associations with
connectivity metrics. Two separate models were used to investigate associations with sFNC,
dFNC and summary metrics from dFNC such as MDT and FT: first model where age, sex and
age-sex interaction were entered as independent (predictor) variables and main effects for
each were examined, and a second model where autistic traits (SRS) was entered as the
independent variable and age, sex and age-sex interaction were added as covariates. All of
the results reported correspond to a false discovery rate multiple comparison correction
threshold q < 0.05.
The following models were used for investigating associations with sFNC. We also checked
the effects of interaction between age-sex and SRS-sex (in Model-1: β I
age i
* sex i
; in Model-2:
β I
SRS i
* sex i
).
Model-1 sFNC
: sFNC i
~ β 0
+β 1
age i
+ β 2
sex i
+ε i
Model-2 sFNC
: sFNC i
~ β 0
+β 1
SRS i
+ β 2
age i
+ β 3
sex i
+ε i
For dFNC analyses, we computed a subject median (computed element-wise) for each
partition from the subject windows that were assigned to that partition as a representative
pattern of connectivity of the subject for that state. To investigate if the observed effects of
age, sex and SRS on sFNC are primarily driven by certain dynamic FNC states, we used these
subject medians for each state, as well as the summary matrices for each state, and evaluated
the associations using two separate models as mentioned above.
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The following models were used for investigating associations with dFNC. We also checked
the effects of interaction between age-sex and SRS-sex (in Model-3: β I
age i
* sex i
; in Model-4:
β I
SRS i
* sex i
).
Model-3 dFNC
: dFNC i state (k) ~ β 0
+β 1
age i
+ β 2
sex i
+ε i
Model-4 dFNC
: dFNC i
state (k)
~ β 0
+β 1
SRS i
+ β 2
age i
+ β 3
sex i
+ε i
The following models were used for investigating associations with summary matrices of
dFNC (MDT and FT). We also checked the effects of interaction between age-sex and SRS-sex
(in Model-5 and Model-7: β I
age i
* sex i
; in Model-6 and Model-8: β I
SRS i
* sex i
).
Model-5 MDT
: MDT i
~ β 0
+β 1
age i
+ β 2
sex i
+ε i
Model-6 MDT
: MDT i
~ β 0
+β 1
SRS i
+ β 2
age i
+ β 3
sex i
+ε i
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