Table 1.
Summary of performance measures (group means ± SD) on the stop-signal task (SST) in young (YA) and older (OA) adults
| YA (n = 25) | OA (n = 26) | t(49) | P | ||
|---|---|---|---|---|---|
| Primary measures | |||||
| GoRT (ms)a | 815.5 (9.5) | 821.6 (20.6) | -1.333 | 0.1888 | |
| GoRT40–20 (ms) | Proactive inhibitionb | 10.26 (6.14) | 13.01 (16.77) | -0.770 | 0.4450 |
| SSRT (ms) | Reactive inhibitionc | 193.1 (12.5) | 206.1 (18.0) | −2.989 | 0.0044 |
| Secondary measures | |||||
| RTSF (ms) | 796.7 (10.0) | 785.4 (26.6) | 1.987 | 0.0525 | |
| SSD (ms) | 616.5 (13.9) | 608.4 (24.5) | 1.442 | 0.1557 | |
| P(inhibit) (%) | 52.60 (1.02) | 52.50 (1.12) | 0.334 | 0.7398 | |
Notes: GoRT, go response time in SST trials with no stop signal (0% SSP); GoRT40–20, difference in Go RTs between SST trials in the 40% and 20% stop-signal probability (SSP) conditions; SSRT, stop-signal reaction time; RTSF, response time on failed stop trials; SSD, stop-signal delay. Performance measures showing significant group differences (P values < 0.05) are indicated in bold. All included participants had a complete dataset of MRI and performance measures.
aTarget GoRT = 800 ms.
bHigher values represent better proactive inhibition.
cHigher values represent poorer reactive inhibition.