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It has been repeatedly shown that temporal task features are reflected in eye blink dynamics during attention tasks. Eye blinks occur with increased likeliness particularly when demands on external attention allocation are low. Both predictive, top-down and reactive, bottom-up processes were shown to be involved in blink regulation. However, whether temporal stimulus prediction is a generally active component of the attention system or rather specific to the visual domain has not been fully elaborated yet. By monitoring eye blinking of 99 students during an auditory attention task and analyzing particularly the dynamics of eye blink onsets relative to stimuli timings, we show here that prediction does, in principle, not require visual stimulation, and is also not merely a consequence of the involvement of manual responses during the task. We further show that both the inclusion of manual response to stimuli and elevated task predictability enhance the prediction component reflected in eye blink dynamics, whereas for the latter we experimentally manipulate objective task predictability by adjusting the frequency dependence of the power spectral densities of the series of inter-stimulus time intervals. This allows us finally to explain why, for specific choices of experimental conditions, the generally active and present prediction component involved in attention can become difficult to detect in non-visual, auditory tasks. Conversely, this comes with the important implication that, if tasks aim for elaborating particularly temporal prediction, distributing stimuli over time such that inter-stimulus-intervals conform to a sample of Gaussian noise represents a specifically unfavorable choice. • The dynamics of eye blinking reflects temporal stimulus prediction. • Prediction and blinking are associated also in purely auditory attention tasks. • The association between blinking and prediction is not mediated by manual response. • Enhancing objective task predictability enhances the association. • Tasks probing temporal prediction should consider the dependence on predictability. [ABSTRACT FROM AUTHOR]

Despite of the crucial role of eye region in nonverbal communication, how and when the brain responds to affective signals projected from this region remains unclear. This study explored the temporal dynamics in the processing of emotionally valenced eye regions (happy, neutral, and fearful) and the influence of attentional resources using a dual-target rapid serial visual presentation task and event-related potential (ERP) technique. Behaviorally, the recognition accuracy of happy and fearful eye regions was higher than that for neutral eye regions in the deficient attentional resources condition (lag2), indicating reduced attentional blink for emotional eye regions. The ERP findings denote that fearful and happy eye regions modulated the N170. The early posterior negativity (EPN) was influenced by the interaction between lag and emotional valence, which was reflected by larger amplitudes for fearful rather than neutral eye regions in the lag2 condition. The amplitude of the late positive potential (LPP) also increased for the happy and fearful eye regions. These outcomes suggest that the human brain is highly sensitive to isolated eye regions. Moreover, fearful signals emitted from the eye region are processed automatically and are unaffected by attentional resource availability. • Human brain is highly sensitive to emotional signals projected from eye region. • Fearful and happy eye regions can attenuate the attentional blink (AB). • P1 and N170 components are affected by attentional resources. • Emotional eye regions differently modulate the amplitudes of N170, EPN and LPP. • Fearful eye regions are processed automatically and preferentially. [ABSTRACT FROM AUTHOR]