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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

BOLD responses in the thalamus (A) and middle frontal gyrus (B) in morning compared with evening types during subjective morning and evening sessions according to working memory load (N0, N2, N3). Contrasts are displayed at p < 0.001, uncorrected threshold, overlaid on the mean normalized structural MR image of the population (n = 28). Corresponding parameter estimates are plotted in the right (arbitrary units).
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Figure 2: BOLD responses in the thalamus (A) and middle frontal gyrus (B) in morning compared with evening types during subjective morning and evening sessions according to working memory load (N0, N2, N3). Contrasts are displayed at p < 0.001, uncorrected threshold, overlaid on the mean normalized structural MR image of the population (n = 28). Corresponding parameter estimates are plotted in the right (arbitrary units).

Mentions: There was no triple interaction effect (chronotype × time of day × N-back level) on BOLD responses in a priori defined areas using the N2>N0 comparison. However, task-related BOLD activity was significantly modulated by chronotype and time of day in the left middle frontal gyrus ([−24 48 10], Z-score = 4.71, psvc = 0.042) and in the thalamus ([−12 −10 4], Z-score = 3.21, psvc = 0.049) in the N3>N0 condition comparison as well in the N3>N2 condition comparison (Figure 2). Note that both regions were also more activated in the 3-back compared with the 0-back condition (p < 0.05, FWE corrected over the entire brain volume, included within the cluster of middle frontal gyrus and thalamus described in Table 1). Furthermore, both regions were previously reported as task load-sensitive brain areas in the literature (20). Overall, post hoc analyses disclosed significant differences between chronotypes during the subjective morning or the subjective evening at the highest working memory load condition (3-back) only. When compared with morning types, evening types exhibited higher thalamic BOLD responses in the N3 (vs. N2 or N0) condition in the evening hours, whereas morning types had higher BOLD responses than evening types in the morning hours in the middle frontal gyrus.


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)

BOLD responses in the thalamus (A) and middle frontal gyrus (B) in morning compared with evening types during subjective morning and evening sessions according to working memory load (N0, N2, N3). Contrasts are displayed at p < 0.001, uncorrected threshold, overlaid on the mean normalized structural MR image of the population (n = 28). Corresponding parameter estimates are plotted in the right (arbitrary units).
© Copyright Policy
Related In: Results  -  Collection

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

Figure 2: BOLD responses in the thalamus (A) and middle frontal gyrus (B) in morning compared with evening types during subjective morning and evening sessions according to working memory load (N0, N2, N3). Contrasts are displayed at p < 0.001, uncorrected threshold, overlaid on the mean normalized structural MR image of the population (n = 28). Corresponding parameter estimates are plotted in the right (arbitrary units).
Mentions: There was no triple interaction effect (chronotype × time of day × N-back level) on BOLD responses in a priori defined areas using the N2>N0 comparison. However, task-related BOLD activity was significantly modulated by chronotype and time of day in the left middle frontal gyrus ([−24 48 10], Z-score = 4.71, psvc = 0.042) and in the thalamus ([−12 −10 4], Z-score = 3.21, psvc = 0.049) in the N3>N0 condition comparison as well in the N3>N2 condition comparison (Figure 2). Note that both regions were also more activated in the 3-back compared with the 0-back condition (p < 0.05, FWE corrected over the entire brain volume, included within the cluster of middle frontal gyrus and thalamus described in Table 1). Furthermore, both regions were previously reported as task load-sensitive brain areas in the literature (20). Overall, post hoc analyses disclosed significant differences between chronotypes during the subjective morning or the subjective evening at the highest working memory load condition (3-back) only. When compared with morning types, evening types exhibited higher thalamic BOLD responses in the N3 (vs. N2 or N0) condition in the evening hours, whereas morning types had higher BOLD responses than evening types in the morning hours in the middle frontal gyrus.

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