Table 1.
Demographic and descriptive statistics.
| Younger Adults (n = 90) Mean (SD) | Middle-Aged (n = 127) | Older Adults (n = 244) | |
|---|---|---|---|
| Age (y) | 29.19 (5.62) | 51.61 (5.45) | 72.48 (7.65) |
| Age Range (y) | 20–39 | 40–59 | 60–89 |
| Male/Female (% Female) | 34/56 (62.2%) | 47/80 (63.0%) | 95/149 (61.1%) |
| PFC Laterality, low demand2 | 0.43 (0.37) | 0.36 (0.37) | 0.28 (0.40) |
| PFC Laterality, high demand | 0.45 (0.33) | 0.43 (0.33) | 0.37 (0.36) |
| VLPFC Laterality, low demand2 | 0.51 (0.37) | 0.49 (0.36) | 0.40 (0.40) |
| VLPFC Laterality, high demand | 0.54 (0.31) | 0.56 (0.30) | 0.49 (0.35) |
| DLPFC Laterality, low demand2 | 0.29 (0.42) | 0.19 (0.43) | 0.15 (0.41) |
| DLPFC Laterality, high demand | 0.29 (0.38) | 0.27 (0.38) | 0.24 (0.39) |
| Fluid Ability (Z-score)1,2,3 | 0.98 (0.63) | 0.37 (0.92) | −0.55 (0.76) |
| Processing Speed (Z-score)1,2,3 | 1.04 (0.76) | 0.30 (0.78) | −0.54 (0.79) |
| Working Memory (Z-score)1,2,3 | 0.66 (0.90) | 0.31 (1.09) | −0.41 (0.78) |
| Reasoning (Z-score)1,2,3 | 0.81 (0.62) | 0.32 (0.91) | −0.47 (0.89) |
| Crystalized Ability (Z-score)1,2 | −0.50 (0.92) | −0.02 (1.11) | 0.19 (0.90) |
| Episodic Memory (Z-score)1,2,3 | 0.59 (0.99) | 0.23 (0.96) | −0.33 (0.89) |
| Judgment RT (low demand)2,3 | 929 (125) | 940 (143) | 1007 (142) |
| Judgment RT (high demand)3 | 1207 (192) | 1207 (174) | 1268 (178) |
| L VLPFC/DLPFC Thickness1,2,3 | 2.63 (0.20) | 2.53 (0.21) | 2.36 (0.20) |
| R VLPFC/DLPFC Thickness1,2,3, | 2.67 (0.18) | 2.51 (0.22) | 2.34 (0.20) |
Note. Laterality index scores closer to 1 indicate stronger left-lateralization and scores closer to 0 reflect more bilateral recruitment; scores were reported for both levels of semantic judgment demand for the combined ventrolateral/dorsolateral prefrontal mask (PFC), as well as individual regions. Z-scores computed from full sample. Between-subjects ANOVAs revealed a main effect of age group for all cognition measures, laterality for the low demand condition, median RTs for both conditions, and cortical thickness in both the left and right prefrontal ROIs (all p’s < 0.01). Abbreviations: DLPFC, dorsolateral prefrontal cortex; VLPFC, ventrolateral prefrontal cortex; RT, response time. Significant differences from Tukey’s HSD test are reported between.
younger and middle-aged adults,
younger and older adults,
middle-aged and older adults.