Long-term memory (LTM) is stored as functional modifications of relevant neural circuits in the brain. A large body of evidence indicates that the initial establishment of such modifications through the process known as memory consolidation requires learning-dependent transcriptional activation and protein synthesis. However, it remains poorly understood how the consolidated memory is maintained for a long period in the brain, despite constant turnover of molecular substrates. Using the courtship conditioning assay of adult males as a memory paradigm, here, we show that in , environmental light plays a critical role in LTM maintenance. LTM is impaired when flies are kept in constant darkness (DD) during the memory maintenance phase. Because light activates the brain neurons expressing the neuropeptide pigment-dispersing factor (Pdf), we examined the possible involvement of Pdf neurons in LTM maintenance. Temporal activation of Pdf neurons compensated for the DD-dependent LTM impairment, whereas temporal knockdown of Pdf during the memory maintenance phase impaired LTM in light/dark cycles. Furthermore, we demonstrated that the transcription factor cAMP response element-binding protein (CREB) is required in the memory center, namely, the mushroom bodies (MBs), for LTM maintenance, and Pdf signaling regulates light-dependent transcription via CREB. Our results demonstrate for the first time that universally available environmental light plays a critical role in LTM maintenance by activating the evolutionarily conserved memory modulator CREB in MBs via the Pdf signaling pathway. Temporary memory can be consolidated into long-term memory (LTM) through protein synthesis and functional modifications of neuronal circuits in the brain. Once established, LTM requires continual maintenance so that it is kept for an extended period against molecular turnover and cellular reorganization that may disrupt memory traces. How is LTM maintained mechanistically? Despite the critical importance of LTM maintenance, its molecular and cellular underpinnings remain elusive. This study using is significant because it revealed for the first time in any organism that universally available environmental light plays an essential role in LTM maintenance. Interestingly, light does so by activating the evolutionarily conserved transcription factor cAMP response element-binding protein via peptidergic signaling.
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http://dx.doi.org/10.1523/JNEUROSCI.1282-19.2019 | DOI Listing |
Neuron
December 2024
Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Center for Neural Science and Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA. Electronic address:
Working memory (WM) and long-term memory (LTM) are often viewed as separate cognitive systems. Little is known about how these systems interact when forming memories. We recorded single neurons in the human medial temporal lobe while patients maintained novel items in WM and completed a subsequent recognition memory test for the same items.
View Article and Find Full Text PDFBiophys Physicobiol
January 2024
Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
Identification of the neural circuits in the brain regulating animal behavior and physiology is critical for understanding brain functions and is one of the most challenging goals in neuroscience research. The fruitfly has often been used to identify the neural circuits involved in the regulation of specific behaviors because of the many neurogenetic tools available to express target genes in particular neurons. Neurons controlling sexual behavior, feeding behavior, and circadian rhythms have been identified, and the number of neurons responsible for controlling these phenomena is small.
View Article and Find Full Text PDFCognition
November 2024
Département de Psychologie, Université de Fribourg, Switzerland. Electronic address:
There is growing evidence that false memories can occur in working memory (WM) tasks with only a few semantically related words and seconds between study and test. Abadie and Camos (2019) proposed a new model to explain the formation of false memories by describing the role of articulatory rehearsal and attentional refreshing, the two main mechanisms for actively maintaining information in WM. However, this model has only been tested in recognition tasks.
View Article and Find Full Text PDFMem Cognit
November 2024
Laboratoire de Psychologie et Neurocognition (LPNC, CNRS 5105), Université Grenoble Alpes, Université Savoie Mont Blanc, 1251 Rue des Universités, 38400, Grenoble, Saint-Martin-d'Hères, France.
Elaboration has emerged as a potential maintenance mechanism involved in the substantial contribution of long-term memory (LTM) to working memory (WM) performance. The objective of the current study was to determine whether elaborative strategies could be spontaneously implemented under favorable conditions. Across four experiments, the distribution of free-time periods was manipulated in a complex span task, while keeping the total amount of free time and cognitive load constant.
View Article and Find Full Text PDFbioRxiv
July 2024
Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA.
Working Memory (WM) and Long-Term Memory (LTM) are often viewed as separate cognitive systems. Little is known about how these systems interact when forming memories. We recorded single neurons in the human medial temporal lobe while patients maintained novel items in WM and a subsequent recognition memory test for the same items.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!