A time to think: Circadian rhythms in human cognition

• Published in: Cognitive neuropsychology Vol. 24; no. 7; pp. 755 - 789
• Main Authors: Schmidt, Christina, Collette, Fabienne, Cajochen, Christian, Peigneux, Philippe
• Format: Journal Article
• Language: English
• Published: Basingstoke Psychology Press 01.10.2007; Taylor and Francis
• Subjects: Adult; Aged; Ageing; Aging - psychology; Arousal; Attention; Biological and medical sciences; Chronotype; Circadian; Circadian Rhythm; Cognition; Cognition. Intelligence; Cognitive performance; Fundamental and applied biological sciences. Psychology; Humans; Individuality; Inhibition (Psychology); Memory; Middle Aged; Miscellaneous; Neuropsychological Tests; Problem Solving; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Psychomotor Performance; Sleep; Thinking; Time of day; Wakefulness; Human; Senescence; Daily variation; Biological rhythm; Cognition; Review; Circadian rhythm
• ISSN: 0264-3294; 1464-0627; 1464-0627
• DOI: 10.1080/02643290701754158

Although peaks and troughs in cognitive performance characterize our daily functioning, time-of-day fluctuations remain marginally considered in the domain of cognitive psychology and neuropsychology. Here, we attempt to summarize studies looking at the effects of sleep pressure, circadian variations, and chronotype on cognitive functioning in healthy subjects. The picture that emerges from this assessment is that beyond physiological variables, time-of-day modulations affect performance on a wide range of cognitive tasks measuring attentional capacities, executive functioning, and memory. These performance fluctuations are also contingent upon the chronotype, which reflects interindividual differences in circadian preference, and particularly upon the synchronicity between the individuals' peak periods of circadian arousal and the time of the day at which testing occurs. In themselves, these conclusions should direct both the clinician's and the researcher's attention towards the utmost importance to account for time-of-day parameters when assessing cognitive performance in patients and healthy volunteers.