Limits...
Pushing the Limits: Chronotype and Time of Day Modulate Working Memory-Dependent Cerebral Activity.

Schmidt C, Collette F, Reichert CF, Maire M, Vandewalle G, Peigneux P, Cajochen C - Front Neurol (2015)

Bottom Line: At the behavioral level, increasing working memory load resulted in lower accuracy while chronotype and time of day only exerted a marginal impact on performance.Our data emphasize interindividual differences in time-of-day preferences and underlying cerebral activity, which should be taken into account when investigating vigilance state effects in task-related brain activity.These results support the hypothesis that higher task complexity leads to a chronotype-dependent increase in thalamic and frontal brain activity, permitting stabilization of working memory performance across the day.

View Article: PubMed Central - PubMed

Affiliation: Cyclotron Research Centre, University of Liège , Liège , Belgium ; Neuropsychology Unit, University of Liège , Liège , Belgium.

ABSTRACT
Morning-type individuals experience more difficulties to maintain optimal attentional performance throughout a normal waking day than evening types. However, time-of-day modulations may differ across cognitive domains. Using functional magnetic resonance imaging (fMRI), we investigated how chronotype and time of day interact with working memory at different levels of cognitive load/complexity in a N-back paradigm (N0-, N2-, and N3-back levels). Extreme morning- and evening-type individuals underwent two fMRI sessions during N-back performance, one 1.5 h (morning) and one 10.5 h (evening) after wake-up time scheduled according to their habitual sleep-wake preference. At the behavioral level, increasing working memory load resulted in lower accuracy while chronotype and time of day only exerted a marginal impact on performance. Analyses of neuroimaging data disclosed an interaction between chronotype, time of day, and the modulation of cerebral activity by working memory load in the thalamus and in the middle frontal cortex. In the subjective evening hours, evening types exhibited higher thalamic activity than morning types at the highest working memory load condition only (N3-back). Conversely, morning-type individuals exhibited higher activity than evening-type participants in the middle frontal gyrus during the morning session in the N3-back condition. Our data emphasize interindividual differences in time-of-day preferences and underlying cerebral activity, which should be taken into account when investigating vigilance state effects in task-related brain activity. These results support the hypothesis that higher task complexity leads to a chronotype-dependent increase in thalamic and frontal brain activity, permitting stabilization of working memory performance across the day.

No MeSH data available.


Related in: MedlinePlus

Accuracy scores (percentage of correct responses minus false alarms) in the N-back task according to the working memory load condition (0-, 2-, 3-back), the time of day (morning, evening), and the chronotype (morning type, evening type). Filled circles: morning types; open circles: evening types.
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Figure 1: Accuracy scores (percentage of correct responses minus false alarms) in the N-back task according to the working memory load condition (0-, 2-, 3-back), the time of day (morning, evening), and the chronotype (morning type, evening type). Filled circles: morning types; open circles: evening types.

Mentions: A repeated-measures ANOVA was conducted on accuracy scores (i.e., hits minus false alarms) with within-subject factors working memory condition and time of day and between-subjects factor chronotype (Figure 1). This analysis revealed a main effect of the working memory condition [F(2,52) = 83.48, p < 0.00001]. Participants performed better on the 0-back than on the 2-and 3-back conditions and better on the 2-back than on the 3-back condition (all ps < 0.001). There was also a main effect of chronotype [F(1,26) = 4.54, p < 0.05] with evening types performing better than morning types irrespective of the condition. The main effect of time of day was not significant [F(1,26) = 0.51, p = 0.48]. The interaction effects between chronotype and time of day [F(1,26) = 2.72, p = 0.11] and between chronotype, time of day, and task condition [F(2,52) = 2.34, p = 0.10] did not reach significance. If considering performance on the N3-back condition (vs. 0-back) separately, there was a significant interaction between chronotype and time of day [F(1,26) = 4.22, p = 0.05]. Evening types performed better than the morning types in the evening in the 3-back condition (p < 0.05). Interaction effects between chronotype and time of day failed to reach significance either considering 2-back vs. 0-back or 3-back vs. 0-back (all ps < 0.1).


Pushing the Limits: Chronotype and Time of Day Modulate Working Memory-Dependent Cerebral Activity.

Schmidt C, Collette F, Reichert CF, Maire M, Vandewalle G, Peigneux P, Cajochen C - Front Neurol (2015)

Accuracy scores (percentage of correct responses minus false alarms) in the N-back task according to the working memory load condition (0-, 2-, 3-back), the time of day (morning, evening), and the chronotype (morning type, evening type). Filled circles: morning types; open circles: evening types.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585243&req=5

Figure 1: Accuracy scores (percentage of correct responses minus false alarms) in the N-back task according to the working memory load condition (0-, 2-, 3-back), the time of day (morning, evening), and the chronotype (morning type, evening type). Filled circles: morning types; open circles: evening types.
Mentions: A repeated-measures ANOVA was conducted on accuracy scores (i.e., hits minus false alarms) with within-subject factors working memory condition and time of day and between-subjects factor chronotype (Figure 1). This analysis revealed a main effect of the working memory condition [F(2,52) = 83.48, p < 0.00001]. Participants performed better on the 0-back than on the 2-and 3-back conditions and better on the 2-back than on the 3-back condition (all ps < 0.001). There was also a main effect of chronotype [F(1,26) = 4.54, p < 0.05] with evening types performing better than morning types irrespective of the condition. The main effect of time of day was not significant [F(1,26) = 0.51, p = 0.48]. The interaction effects between chronotype and time of day [F(1,26) = 2.72, p = 0.11] and between chronotype, time of day, and task condition [F(2,52) = 2.34, p = 0.10] did not reach significance. If considering performance on the N3-back condition (vs. 0-back) separately, there was a significant interaction between chronotype and time of day [F(1,26) = 4.22, p = 0.05]. Evening types performed better than the morning types in the evening in the 3-back condition (p < 0.05). Interaction effects between chronotype and time of day failed to reach significance either considering 2-back vs. 0-back or 3-back vs. 0-back (all ps < 0.1).

Bottom Line: At the behavioral level, increasing working memory load resulted in lower accuracy while chronotype and time of day only exerted a marginal impact on performance.Our data emphasize interindividual differences in time-of-day preferences and underlying cerebral activity, which should be taken into account when investigating vigilance state effects in task-related brain activity.These results support the hypothesis that higher task complexity leads to a chronotype-dependent increase in thalamic and frontal brain activity, permitting stabilization of working memory performance across the day.

View Article: PubMed Central - PubMed

Affiliation: Cyclotron Research Centre, University of Liège , Liège , Belgium ; Neuropsychology Unit, University of Liège , Liège , Belgium.

ABSTRACT
Morning-type individuals experience more difficulties to maintain optimal attentional performance throughout a normal waking day than evening types. However, time-of-day modulations may differ across cognitive domains. Using functional magnetic resonance imaging (fMRI), we investigated how chronotype and time of day interact with working memory at different levels of cognitive load/complexity in a N-back paradigm (N0-, N2-, and N3-back levels). Extreme morning- and evening-type individuals underwent two fMRI sessions during N-back performance, one 1.5 h (morning) and one 10.5 h (evening) after wake-up time scheduled according to their habitual sleep-wake preference. At the behavioral level, increasing working memory load resulted in lower accuracy while chronotype and time of day only exerted a marginal impact on performance. Analyses of neuroimaging data disclosed an interaction between chronotype, time of day, and the modulation of cerebral activity by working memory load in the thalamus and in the middle frontal cortex. In the subjective evening hours, evening types exhibited higher thalamic activity than morning types at the highest working memory load condition only (N3-back). Conversely, morning-type individuals exhibited higher activity than evening-type participants in the middle frontal gyrus during the morning session in the N3-back condition. Our data emphasize interindividual differences in time-of-day preferences and underlying cerebral activity, which should be taken into account when investigating vigilance state effects in task-related brain activity. These results support the hypothesis that higher task complexity leads to a chronotype-dependent increase in thalamic and frontal brain activity, permitting stabilization of working memory performance across the day.

No MeSH data available.


Related in: MedlinePlus