Learning and Circadian Behavior

Daan, Serge

doi:10.1177/074873000129001396

Cited by 22 publications

(15 citation statements)

References 20 publications

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“…During learning and the formation of memory, information may be stored in a time-stamped manner such that peak recall may occur in 24-h intervals after training or the time of day may become a contextual component of learning (29)(30)(31)(32). The rhythm of LTS is a case of modulation by the circadian clock and not a contextual time-stamping event, because animals trained in the subjective day exhibited LTS when tested either in the subjective day or night.…”

Section: Discussionmentioning

confidence: 99%

Circadian modulation of long-term sensitization in Aplysia

Fernandez

Lyons

Levenson

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

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As the mechanisms for learning and memory are elucidated, modulation of learning and memory becomes a central issue. We studied the modulation of learning and memory by investigating the circadian regulation of short-and long-term sensitization of the siphon withdrawal reflex in Aplysia. We found that Aplysia exhibited diurnal and circadian rhythms of long-term sensitization (LTS) with significantly greater LTS occurring when animals were trained and tested during the day relative to those trained and tested at night. In contrast to the modulation of LTS, short-term sensitization was not regulated by the circadian clock. Time of training rather than time of testing determined the circadian rhythm of LTS. Animals trained during the subjective day demonstrated LTS when tested during either the day or the night. Conversely, when animals were trained during the night, LTS was not observed when animals were tested either at night or during the day. Thus, the circadian rhythm of LTS is a rhythm in learning rather than a rhythm in recall. The threshold required to elicit siphon withdrawal and the duration of siphon withdrawal were not regulated by the circadian clock. These results indicate that the circadian oscillator exerts strong modulatory influences on one form of long-term memory in Aplysia.H ow organisms learn has been of interest for centuries as people seek to understand and improve learning and memory abilities. One aspect of understanding learning and memory is determining how these processes are normally modulated. What conditions modulate learning and memory, and how does regulation occur? General health, motivation, age, stress, sleep patterns, and time of day may modulate learning and memory. The circadian clock regulates many behavioral and physiological processes, making it likely that circadian modulation of learning and memory also occurs (1).Circadian modulation of learning and memory has been investigated with varied results. Some studies have indicated time of day influences memory in humans (2-4), whereas other studies have found little impact of time of day on memory (5). Researchers studying hippocampus-dependent learning found that rats trained at midday showed decreased retention compared with animals trained earlier or later (6). However, other researchers found no time-of-day effects on multiple learning tasks (7). Furthermore, two laboratories studying contextual fear conditioning in mice reported different effects of the circadian clock on learning and memory (8, 9). The issue of circadian modulation of learning and memory remains to be determined.Indirect evidence for circadian modulation of learning and memory comes from in vitro studies of long-term potentiation. Researchers have documented diurnal and circadian differences in long-term potentiation in the hippocampus (10, 11). Additional studies have also found that excitability of CA3 neurons is regulated diurnally (12). Thus, some mechanisms exist for learning and memory to be rhythmic. Experiments demonstrating that consolidation ...

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Section: Discussionmentioning

confidence: 99%

Circadian modulation of long-term sensitization in Aplysia

Fernandez

Lyons

Levenson

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

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“…Animals seem to recall events that happen at 24 h intervals more accurately in some experimental situations (e.g. Daan 2000; Pahl et al 2007; Prabhu and Cheng 2008a; Zhang et al 2006). Yet, models of tracking and adaptive memory do not incorporate these special intervals.…”

Section: Introductionmentioning

confidence: 99%

Tracking a changing environment: optimal sampling, adaptive memory and overnight effects

Dunlap

Stephens

2012

Behavioural Processes

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Foraging in a variable environment presents a classic problem of decision making with incomplete information. Animals must track the changing environment, remember the best options and make choices accordingly. While several experimental studies have explored the idea that sampling behavior reflects the amount of environmental change, we take the next logical step in asking how change influences memory. We explore the hypothesis that memory length should be tied to the ecological relevance and the value of the information learned, and that environmental change is a key determinant of the value of memory. We use a dynamic programming model to confirm our predictions and then test memory length in a factorial experiment. In our experimental situation we manipulate rates of change in a simple foraging task for blue jays over a 36 hour period. After jays experienced an experimentally determined change regime, we tested them at a range of retention intervals, from 1 to 72 hours. Manipulated rates of change influenced learning and sampling rates: subjects sampled more and learned more quickly in the high change condition. Tests of retention revealed significant interactions between retention interval and the experienced rate of change. We observed a striking and surprising difference between the high and low change treatments at the 24 hour retention interval. In agreement with earlier work we find that a circadian retention interval is special, but we find that the extent of this ‘specialness’ depends on the subject’s prior experience of environmental change. Specifically, experienced rates of change seem to influence how subjects balance recent information against past experience in a way that interacts with the passage of time.

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“…While much of the basic physiology under control of circadian pacemakers has been well-studied, the interactions between these processes and cognitive behavior have been relatively unexplored. Although there is evidence that performance and learning may be influenced by circadian processes (for reviews, see Daan 2000;Gerstner and Yin 2010), we have little information about how regularly timed cognitive processes impact circadian rhythms; in particular, can rhythms be modified by experience to optimize task acquisition or augment performance?…”

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confidence: 98%

Bidirectional interactions between circadian entrainment and cognitive performance

Gritton

Kantorowski

Sarter³

et al. 2012

Learn. Mem.

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Circadian rhythms influence a variety of physiological and behavioral processes; however, little is known about how circadian rhythms interact with the organisms' ability to acquire and retain information about their environment. These experiments tested whether rats trained outside their endogenous active period demonstrate the same rate of acquisition, daily performance, and remote memory ability as their nocturnally trained counterparts in tasks of sustained attention and spatial memory. Furthermore, we explored how daily task training influenced circadian patterns of activity. We found that rats demonstrate better acquisition and performance on an operant task requiring attentional effort when trained during the dark-phase. Time of day did not affect acquisition or performance on the Morris water maze; however, when animals were retested 2 wk after their last day of training, they showed better remote memory if training originally occurred during the dark-phase. Finally, attentional, but not spatial, task performance during the light-phase promotes a shift toward diurnality and the synchronization of activity to the time of daily training; this shift was most robust when the demands on the cognitive control of attention were highest. Our findings support a theory of bidirectional interactions between cognitive performance and circadian processes and are consistent with the view that the circadian abnormalities associated with shift-work, aging, and neuropsychiatric illnesses may contribute to the deleterious effects on cognition often present in these populations. Furthermore, these findings suggest that time of day should be an important consideration for a variety of cognitive tasks principally used in psychological and neuroscience research.

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Learning and Circadian Behavior

Cited by 22 publications

References 20 publications

Circadian modulation of long-term sensitization in Aplysia

Circadian modulation of long-term sensitization in Aplysia

Tracking a changing environment: optimal sampling, adaptive memory and overnight effects

Bidirectional interactions between circadian entrainment and cognitive performance

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