The role of chronotype in the interaction between the alerting and the executive control networks

Abstract

Chronotype refers to the time of day preferred by individuals to perform daily activities according to their circadian rhythm. We asked whether synchrony effects, that is, the difference in performance between the optimal and non-optimal time of day as a function of chronotype, are observed in two tasks that differently involve the endogenous component of the alerting network, the psychomotor visual task (PVT) and the flanker task. From an initial sample of 132 students that filled in the Morningness–Eveningness Questionnaire (MEQ), 18 were classified as Morning-types and 16 as Evening-types. Evening-types showed synchrony effects in both tasks, whereas Morning-types failed to show synchrony effects in the flanker task and when the PVT was first performed at the non-optimal time of day. Thus, Morning-types might have seen increased their vigilant attention at their non-optimal time of day due to the cognitive demands of the flanker task and to the novelty with the PVT. Phasic alerting generated by alerting tones increased conflict score in the flanker task, but time of day did not modulate the congruence effect. Chronotype determines vigilant attention more decisively in Evening-types than in Morning-types individuals. Also, exogenous but not endogenous alerting exerts a deleterious effect on conflict resolution.

Propensity to intentional and unintentional mind-wandering differs in arousal and executive vigilance tasks

“…If intentional mind-wandering is mainly promoted in arousal-based vigilance tasks, we would predict that, in this type of tasks, intentional mind-wandering will be practically nonexistent when the individual is in circumstances that normally involve low levels of arousal. This is the case of sleep deprivation, or when the task is performed at the non-optimal time-of-day according to circadian rhythms [ 29 ]. In these situations, proper execution of the task will require greater cognitive effort, so it is to be expected that unintentional rather than intentional mind-wandering will be observed over time, as with tasks that require high levels of cognitive control.…”

“…Participants were randomly assigned to the order in which they performed the tasks, so that approximately half of the participants performed the SART in the first session and the PVT in the second session, and the other way around for the other half of the participants. The tasks were performed at a time interval from 10 am to 1 pm to prevent the performance from being influenced by participants’ chronotype and time of testing (see [ 29 ]).…”

Alpha and Theta Transcranial Alternating Current Stimulation Over the Right Dorsolateral Prefrontal Cortex Modulates Vigilance Performance, but Only When Arousal Levels Are Non-optimal

“…Due to the monotonous nature of some repetitive tasks that make scarce requirements of cognitive resources, it is expected that participants diminish their interest and lose the focus on the task. In previous research, we have observed that evening-types participants showed the synchrony effect, that is, they produced longer RTs when they performed the monotonous task (PVT) at their non-optimal time of day compared with when they performed the task at the optimal time of day [13]. Importantly, when the RT distribution was computed, the synchrony effect became larger at the slower end of the distribution, that is, when extreme uctuations of attention emerged at the non-optimal time of day.…”

“…Beside both time-on-task and type of task, vigilance is affected by two important factors that determine how e ciently people sustain attention in vigilance tasks, the individual differences in circadian rhythms (e.g., chronotype [13]) and the oscillatory nature of attention (e.g., cortical oscillations in the frontoparietal network [9]).…”

“…Martínez-Pérez et al [13] showed that evening-types performed better at their optimal time of day compared with their non-optimal time of day in both a task involving arousal vigilance (the PVT) and a con ict task that required executive vigilance (the anker task). Morning-types, however, only showed this kind of synchrony effect in the PVT, and this effect was, moreover, smaller in comparison with that found with evening-types.…”