Revision as of 18:11, 2 April 2015

This Week

03 April 2015 (YOUNG INVESTIGATOR SEMINAR)

Time: 09:30 am

Place : Gonda 2nd Floor Conference Room

Title: Rodent Hippocampal Activity in Real and Virtual Environments

Speaker: Zahra M. Aghajan (Mehta Lab)

The hippocampus is linked to our ability to form episodic memories by providing a spatial cognitive map together with the content of experiences. In rodents, the focus has largely been on the role of hippocampus in the representation of space but despite decades-long research, the underlying mechanisms remain unknown. It has been shown that multiple sensory and motor inputs reach the hippocampus and can modulate its activity. In real world (RW) environments however, the contributions of these inputs are confounded. Thus, to dissociate these contributions and thereby elucidate the mechanisms of spatial selectivity, we used a virtual reality (VR) setup.

We found comparable levels of hippocampal spatiotemporal selectivity on linear tracks in RW and VR. In contrast, during random foraging in two-dimensions, spatial selectivity was severely diminished in VR. Nevertheless, most spikes occurred within ~2-s-long hippocampal motifs—with similar structure to that in RW—within which hippocampal temporal code was intact, demonstrating a decoupling between the spatial and the temporal codes. Further, additional experiments and analysis revealed significant directional selectivity in the hippocampus in RW and VR. Notably, contrary to the impairment of spatial selectivity in VR, the degree of directional selectivity was identical in both worlds and determined by the angular information contained in the visual cues. Taken together, these results suggest that while visual cues alone are insufficient to generate a stable localized representation in the spatial domain, they are sufficient to elicit—and play a causal role in—hippocampal directional selectivity.

Relevant papers: http://www.sciencemag.org/content/340/6138/1342.full

http://www.nature.com/neuro/journal/v18/n1/full/nn.3884.html

http://biorxiv.org/content/early/2015/03/28/017210

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:

Dean Buonomano

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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