ICLM Journal Club
This Week
Jason Moore
Title: 'Hippocampal Neural Activity in a Virtual Morris Water Maze'
Abstract: It is commonly believed that a stable cognitive map of space is necessary for the successful execution of any navigation task. Indeed, removal or impairment of the hippocampus, which contains place cells thought to underlie the cognitive map, impairs performance in the Morris Water Maze task, demonstrating a crucial role of hippocampal activity in this task. However, it is unclear if this also means that hippocampal spatial selectivity is required for successful execution of this landmark-based spatial navigation task. Using virtual reality equipment, rats can be trained to solve a virtual Morris Water Maze task, where they must pay attention to the visual cues. This holds a number of advantages, including decreased stress on the animal, and a dry recording condition facilitating electrophysiological recording. I will present results from measuring neural responses from the dorsal hippocampus while the rats executed this virtual navigation task. Surprisingly, we found weak allocentric spatial selectivity in pyramidal neurons of CA1, traditionally described as “place cells.” Instead, these cells showed strong tuning to the distance the rat had traveled, regardless of start position. We also observed directional tuning as well as temporal modulation around the time of reward. These results demonstrate that allocentric spatial selectivity is not necessary for successful landmark-based navigation. Instead, a representation of distance travelled combined with head direction information is sufficient to solve this task and generate an expectation of reward at the appropriate time.
Related Papers: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0080465 http://www.sciencedirect.com/science/article/pii/S0092867415016396
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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