Speaker: Alex Chubykin

Title: Impaired Visual Familiarity Circuit in Fmr1 KO Mice

Abstract: The brain differentially processes information, depending on its familiarity. To differentiate between familiar and novel stimuli, the brain needs to be able to recognize familiar stimuli or their prominent physical features. However, there has been a poor understanding of how this process occurs at the mechanistic level. We have recently discovered a new mechanism encoding visual familiarity via persistent low-frequency oscillations in the mouse primary visual cortex (V1). We then determined that the familiarity-evoked oscillations are attenuated in the Fmr1 KO mice, the mouse model of Fragile X syndrome, the most common inherited form of autism and intellectual disability. To identify the neuronal circuit involved in the generation of these oscillations, we have performed channelrhodopsin-assisted circuit mapping (CRACM). We have discovered that following visual experience, there was an increase in the strength of the excitatory connections formed by the pyramidal neurons in layer 5 onto the fast-spiking interneurons in layer 4. Interestingly, this connection was weaker in the Fmr1 KO mice, which correlated with the weaker familiarity-evoked oscillations in vivo. Our findings suggest the critical role of the intracortical excitatory connections onto fast-spiking interneurons for the visual familiarity in V1.

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:

Shonali Dhingra

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)

v) Walt Babiec (O'Dell Lab) (2013-2014)

vi) Walt Babiec (O'Dell Lab) & Helen Motanis (Buonomano Lab) (2014-2017)

vii) Helen Motanis (Buonomano Lab) & Shonali Dhingra (Mehta Lab) (2017-2018)

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