ICLM Journal Club
This Week
9 January 2015 YOUNG INVESTIGATOR SEMINAR
Time: 09:30 am
Place : Gonda 2nd Floor Conference Room
Title: Pronounced impact of out of phase food intake on learning and memory
Speaker: Dawn Loh (Colwell Lab)
The circadian system is a finely tuned network of central and peripheral oscillators headed by a master pacemaker, the suprachiasmatic nucleus (SCN), which governs daily rhythms in behavior and physiology, including cognition. Disruption of the circadian system by genetic mutations or environmental manipulations has severe consequences on learning and memory. In prior work, we established the negative impact of acute jet lag on cognition, demonstrating that acute misalignment of the network of circadian oscillators has pronounced effects on long term memory.
In this study, we sought to determine the effects of chronic and stable misalignment of the circadian network by scheduling access to food at an inappropriate phase of the daily cycle, which alters the phase of many peripheral circadian oscillators without affecting the SCN. Mice were allotted a six hour window in which food was made available either during their active phase (aligned), or during their inactive phase (misaligned). Crucially, in the central nervous system, we determined that misaligned feeding alters the phase of the hippocampal circadian oscillator.
Chronic misalignment of food access resulted in reduced performance on the novel object recognition test and had a severe impact on the recall of contextual fear conditioning, indicating deficits in hippocampal-dependent learning and memory. Critically, although the temporal pattern of sleep was altered, there was no difference in the amount of sleep between the aligned and misaligned groups, thus ruling out effects of sleep deprivation on memory. At the physiological level, misaligned feeding led to deficits in hippocampal long term potentiation, suggesting circadian disruption affects synaptic plasticity.
Our findings suggest that circadian misalignment of the hippocampal oscillator has far-reaching effects on not only hippocampal physiology, but also on the functional outcome of long term memory, and highlight the importance of circadian regulation on cognition.
About Us
Introduction
The Integrative Center for Learning and Memory (ICLM) is a multidisciplinary center of UCLA labs devoted to understanding the neural basis of learning and memory and its disorders. This will require a unified approach across different levels of analysis, including;
1. Elucidating the molecular cellular and systems mechanisms that allow neurons and synapses to undergo the long-term changes that ultimately correspond to 'neural memories'.
2. Understanding how functional dynamics and computations emerge from complex circuits of neurons, and how plasticity governs these processes.
3. Describing the neural systems in which different forms of learning and memory take place, and how these systems interact to ultimately generate behavior and cognition.
History of ICLM
The Integrative Center for Learning and Memory formally LMP started in its current form in 1998, and has served as a platform for many interactions and collaborations within UCLA. A key event organized by the group is the weekly ICLM Journal Club. For more than 10 years, graduate students, postdocs, principal investigators, and invited speakers have presented on topics ranging from the molecular mechanisms of synaptic plasticity, through computational models of learning, to behavior and cognition. Dean Buonomano oversees the ICLM journal club with help of student/post doctoral organizers. For other events organized by ICLM go to http://www.iclm.ucla.edu/Events.html.
Current Organizers:
Walt Babiec (O'Dell Lab) & Helen Motanis (Buonomano Lab)
Current Faculty Advisor:
Past Organizers:
i) Anna Matynia(Aug 2004 - Jun 2008) (Silva Lab)
ii) Robert Brown (Aug 2008 - Jun 2009) (Balleine Lab)
iii) Balaji Jayaprakash (Aug 2008 - Nov 2011) (Silva Lab)
iv) Justin Shobe & Thomas Rogerson (Dec 2011 - June 2013) (Silva Lab)
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