Age-related changes in orienting attention in time

Abstract

Temporal cues guide attentional resources toward relevant points in time, resulting in optimized behavioral performance. Although deficits in aspects of attention have been documented in older adults, it remains unknown whether the critical ability to orient attention in time is affected by normal aging. To address this, younger and older adults participated in a temporally cued target-response experiment while electroencephalographic data were recorded. Three conditions (one detection and two discrimination tasks) were used to manipulate task complexity. Response times show that younger adults, but not older adults, used temporal cues to enhance performance regardless of task complexity. Similarly, alpha band activity (8-12 Hz) and the contingent negative variation preceding targets indicated that only younger adults engaged prestimulus, anticipatory neural mechanisms associated with temporal cues. Overall, these results provide novel evidence that older adults do not use temporal cues to orient attention in time and support an expectation deficit in normal aging.

Figure 1.

Experimental paradigm. The cue and target were randomly selected for each trial from three different cue types and two different target types. S, Short foreperiod (600 ms); L, long foreperiod (1400 ms); N, neutral cue (600 or 1400 ms); ITI, intertrial interval. The meaning of the target (x or +) was contingent on the experimental condition (detection, go/no-go, or forced choice).

Figure 2.

Summary of age-related changes in response time benefits from predictive cues. Only younger adults benefit from predictive cues preceding a short foreperiod (PS). *p < 0.05.

Figure 3.

Age-dependent changes across conditions. A, Response times following a long foreperiod were not different between age groups for the easiest task (detection). However, age-related slowing was observed during tasks that required more cognitive processing (go/no-go and forced choice). B, Similar to response times, the latency of the P3 was delayed in older adults only during tasks that required more cognitive processing than detection. *p < 0.05.

Figure 4.

ERP to the cue from the left hemisphere ROI. Older adults show a delay at the N1 (∼170 ms following cue onset).

Figure 5.

ERPs from the central–posterior ROI. Vertical black lines indicate stimulus onset (cue, 0 ms; target, 700 or 1500 ms). Measures of the terminal CNV (gray box) were subject to analysis. A, Younger adults elicited a larger CNV following PS compared with NS. B, Older adults did not show any cue-related differences in their CNV (NS vs PS). C, D, Younger (C) and older (D) adults did not show cue-related differences in their CNV during the long foreperiods. *p < 0.001.

Figure 6.

Alpha (8–12 Hz) activity from the right posterior ROI. Vertical black lines indicate stimulus onset (cue, 0 ms; target, 700 or 1500 ms). Measures of alpha activity (gray box) were subject to analysis. A, Younger adults elicited more negative alpha activity following PS compared with NS. B, Older adults also showed more negative alpha activity following PS compared with NS, although the magnitude of modulation is less than younger adults. C, D, Younger (C) and older (D) adults did not show cue-related differences in their alpha activity during the long foreperiods. *p < 0.005.