A time to remember: The role of circadian clocks in learning and memory.

Abstract

The circadian system has pronounced influence on learning and memory, manifesting as marked changes in memory acquisition and recall across the day. From a mechanistic level, the majority of studies have investigated mammalian hippocampal dependent learning and memory, as this system is highly tractable. The hippocampus plays a major role in learning and memory and has the potential to integrate circadian information in many ways, including information from local, independent oscillators, and through circadian modulation of neurogenesis, synaptic remodeling, intracellular cascades, and epigenetic regulation of gene expression. These local processes are combined with input from other oscillatory systems to synergistically augment hippocampal rhythmic function. This overview presents an account of the current state of knowledge on circadian interactions with learning and memory circuitry and provides a framework for those interested in further exploring these interactions.

The primate seahorse rhythm

“…The circadian system can also influence the acquisition and recall of learned behaviors (Chaudhury and Colwell, 2002;Eckel-Mahan et al, 2008;Fernandez et al, 2003;Lyons et al, 2006) both in rodents (Chaudhury and Colwell, 2002;Hauber and Bareiss, 2001;Lyons et al, 2005) and humans, in which time of day influences memory (Maury and Queinnec, 1992;Nesca and Koulack, 1994). These observations suggest a fundamental interaction between the functions and processing of the hippocampus and the circadian system (Hauber and Bareiss, 2001;Martin-Fairey and Nunez, 2014;Nesca and Koulack, 1994;Smarr et al, 2014).…”

“…Furthermore, it may participate in a variety of autonomic, neuroendocrine, defensive, ingestion-related and reproductive control systems (Bannerman et al, 2004;Kjelstrup et al, 2008). Many of these features are interlinked and are responsive to environmental changes (Hauber and Bareiss, 2001;MartinFairey and Nunez, 2014;Smarr et al, 2014). The light/dark cycle is the most striking of the environmental variations that are able to exert a potent synchronizer role in the biological rhythms (Moore-Ede et al, 1982;Mrosovsky and Salmon, 1987;Rea, 1998).…”

“…This is reflected in behaviors such as sleep-wake behavior, body temperature, the regulation of hormone secretion, and the acquisition and processing of memory (Chaudhury and Colwell, 2002;Gerstner et al, 2009;Nesca and Koulack, 1994;Ruby et al, 2008Ruby et al, , 2013. Different models in rodents and humans have highlighted remarkable changes in cognitive functions, memory acquisition and recall across the day as well as the circadian modulation of neurogenesis, synaptic remodeling, intracellular cascades, and the epigenetic regulation of gene expression (Hauber and Bareiss, 2001;Martin-Fairey and Nunez, 2014;Smarr et al, 2014). Furthermore, functions such as processing and learning in the hippocampal memory have been described as important to integrate the circadian information of independent oscillators (Garren et al, 2013;Maury and Queinnec, 1992;Nesca and Koulack, 1994;Smarr et al, 2014).…”

“…Different models in rodents and humans have highlighted remarkable changes in cognitive functions, memory acquisition and recall across the day as well as the circadian modulation of neurogenesis, synaptic remodeling, intracellular cascades, and the epigenetic regulation of gene expression (Hauber and Bareiss, 2001;Martin-Fairey and Nunez, 2014;Smarr et al, 2014). Furthermore, functions such as processing and learning in the hippocampal memory have been described as important to integrate the circadian information of independent oscillators (Garren et al, 2013;Maury and Queinnec, 1992;Nesca and Koulack, 1994;Smarr et al, 2014). Some of these models have shown evidence of the rhythmic expression of clock genes in the hippocampus (Duncan et al, 2013;Lamont et al, 2005;Otalora et al, 2013;Verwey et al, 2007).…”

Fragmentation of Rapid Eye Movement and Nonrapid Eye Movement Sleep without Total Sleep Loss Impairs Hippocampus-Dependent Fear Memory Consolidation

“…24,25 Prior studies showed that circadian desynchrony disrupts learning and memory. 26 Circadian disruption through constant light exposure impairs hippocampus-dependent memory. 27,28 In Siberian hamsters, a one-time photic treatment that results in circadian arrhythmicity impairs novel-object recognition.…”