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Unconscious processes are often assumed immune from attention influence. Recent behavioral studies suggest however that the processing of subliminal information can be influenced by temporal attention. To examine the neural mechanisms underlying these effects, we used a stringent masking paradigm together with fMRI to investigate how temporal attention modulates the processing of unseen (masked) faces. Participants performed a gender decision task on a visible neutral target face, preceded by a masked prime face that could vary in gender (same or different than target) and emotion expression (neutral or fearful). We manipulated temporal attention by instructing participants to expect targets to appear either early or late during the stimulus sequence. Orienting temporal attention to subliminal primes influenced response priming by masked faces, even when gender was incongruent. In addition, gender-congruent primes facilitated responses regardless of attention while gender-incongruent primes reduced accuracy when attended. Emotion produced no differential effects. At the neural level, incongruent and temporally unexpected primes increased brain response in regions of the fronto-parietal attention network, reflecting greater recruitment of executive control and reorienting processes. Congruent and expected primes produced higher activations in fusiform cortex, presumably reflecting facilitation of perceptual processing. These results indicate that temporal attention can influence subliminal processing of face features, and thus facilitate information integration according to task-relevance regardless of conscious awareness. They also suggest that task-congruent information between prime and target may facilitate response priming even when temporal attention is not selectively oriented to the prime onset time.

We investigated the neural mechanisms and the autonomic and cognitive responses associated with visual avoidance behavior in spider phobia. Spider phobic and control participants imagined visiting different forest locations with the possibility of encountering spiders snakes or birds (neutral reference category). In each experimental trial participants saw a picture of a forest location followed by a picture of a spider snake or bird and then rated their personal risk of encountering these animals in this context as well as their fear. The greater the visual avoidance of spiders that a phobic participant demonstrated (as measured by eye tracking) the higher were her autonomic arousal and neural activity in the amygdala orbitofrontal cortex (OFC) anterior cingulate cortex (ACC) and precuneus at picture onset. Visual avoidance of spiders in phobics also went hand in hand with subsequently reduced cognitive risk of encounters. Control participants in contrast displayed a positive relationship between gaze duration toward spiders on the one hand and autonomic responding as well as OFC ACC and precuneus activity on the other hand. In addition they showed reduced encounter risk estimates when they looked longer at the animal pictures. Our data are consistent with the idea that one reason for phobics to avoid phobic information may be grounded in heightened activity in the fear circuit which signals potential threat. Because of the absence of alternative efficient regulation strategies visual avoidance may then function to down regulate cognitive risk evaluations for threatening information about the phobic stimuli. Control participants in contrast may be characterized by a different coping style whereby paying visual attention to potentially threatening information may help them to actively down regulate cognitive evaluations of risk.