FAST PLASTICITY OF LONG-RANGE INTERACTIONS INDUCED BY TEMPORAL CUEING
Y. Tanaka and D. Sagi (2000) Investigative Ophthalmology and Visual Science (ARVO abstract) 41(4) pp49.

Purpose: To explore the relationship between attentional priming and plasticity in early vision. Methods: Detection thresholds were measured for a foveal Gabor Signal (GS; sigma=lambda=0.2°, C=0.3) with collinear GS flankers (distance, 0-16 lambda), with and without temporal cueing. In the temporal uncertainty (no cue) condition, each target interval (90 ms) was preceded by a random time delay (800-1300 ms). In the temporal cue condition, four peripheral crosses were inserted (90 ms) 270-450 ms (depending on observers) before target presentation, where enhanced detection was observed. Long-range interactions were tested with temporal uncertainty (3 sessions, no-cue condition), followed by time-locked cued presentations (3-10 sessions, cue condition), and a final no-cue condition (3-4 sessions). Results: In the first no-cue condition, threshold showed a typical enhancement at distances of 2-6 lambda, maximum at 3 lambda (0.24±0.09 log units, average±SE, 3 observers). Temporal cue produced an additional threshold reduction of 0.18±0.06 log units with flankers at distances of 4-16 lambda, without any noticeable change across sessions. Cued threshold without flankers decreased by 0.15±.03 log units. In the following no-cue condition, the improved thresholds in the range of 4-16 lambda distance was preserved (0.22±0.07 log units) while absolute threshold was the same as in the first no-cue sessions. This improvement persisted for months. No temporal cueing effects and learning were observed at the short-range (0-1 lambda) distances. A supplementary experiment showed that a few minutes of practice with temporal cueing can generate the enhanced long-range facilitation. Conclusions: The selective transfer of time-cued lateral facilitation to non cued conditions, indicates that an efficient application of attention to visual stimuli, via temporal cueing, can produce long term changes within early vision, here modifying long-range excitatory interactions. Time-cued learning is much faster (minutes) than observed before with similar stimuli (2 weeks, Polat and Sagi, 1994), yet long-term (months), suggesting that attention plays a critical role in memory consolidation.