Table 3.
Posttraumatic stress symptoms averaged across 24 years and bilateral cortical, anterior cingulate, and subcortical brain volumetrics in late midlife.
| Model 1 (predictive) | Model 2 (Full) | |||
|---|---|---|---|---|
| Brain ROI (Time 2) | β | P | β | p |
| Subcortical Structures | ||||
| Hippocampal Volume | −0.17 (.07) | 0.01 | −0.21 (.09) | 0.02 |
| Hippocampal Occupancy | −0.13 (.06) | 0.05 | −0.15 (.09) | 0.08 |
| Amygdala | −0.17 (.06) | 0.01 | −0.12 (09) | 0.17 |
| Anterior Cingulate (ACC) Volumes | ||||
| Rostral ACC | 0.02 (.07) | 0.72 | 0.01 (.09) | 0.87 |
| Caudal ACC | 0.08 (.06) | 0.19 | 0.10 (.08) | 0.24 |
| Prefrontal Cortex (PFC) Volumes (Exploratory) | ||||
| Caudal Middle Frontal Gyrus | −0.11 (.06) | 0.09 | −0.12 (.08) | 0.13 |
| Rostral Middle Frontal Gyrus | −0.20 (.06) | <0.001 | −0.23 (.08) | 0.01 |
| Superior Frontal Gyrus | −0.12 (.06) | 0.05 | −0.16 (.08) | 0.05 |
| Pars Orbitalis | −0.06 (.07) | 0.37 | −0.05 (.09) | 0.55 |
| Pars Opercularis | −0.05 (.07) | 0.41 | −0.08 (.09) | 0.35 |
| Pars Triangularis | −0.11 (.07) | 0.11 | −0.23 (.09) | 0.01 |
| Medial Orbitofrontal Cortex | −0.15 (.06) | 0.01 | −0.16 (.08) | 0.05 |
| Lateral Orbitofrontal Cortex | −0.05 (.07) | 0.42 | −0.02 (.09) | 0.84 |
| Frontal Pole | −0.13 (.07) | 0.07 | −0.15 (.09) | 0.10 |
ROI=Region of interest. Numbers in the table are parameter estimates (β coefficients), standard errors (SE), and p-values from mixed models that account for non-independence of observations within twin pairs. Model 1 (predictive; N=247 df=60) uses the average of time 1 and time 2 PTS symptoms as the independent variable as well as ethnicity (non-Hispanic white vs other), early adult cognitive ability, apolipoprotein epsilon 4 (APOE) status (presence of any ε4 allele [ε4+] versus none [ε4-]), head injury (yes, no), number of combat exposures, number of severe childhood traumas and age as covariates; Model 2 additionally includes time 2 covariates for smoking (yes, no), alcohol consumption, chronic health conditions, Centers for Disease Control Depression Scale (CES-D), and life events. ROI measures are residuals of brain structure volume adjusted for scanner/site and intracranial volume. Bolded exploratory PFC values are those significant following correction for multiple comparisons.