ICLM Journal Club
This Week - 20 December 2019 (9:30 a.m., Gonda 2nd Floor Conference Room)
Speaker: Claudio Villalobos
Title: “Control of mice orienting movement by optogenetic activation of the inhibitory nigrocollicular pathway”
Abstract: The current model controlling orienting movements in mammals indicates that bursting of iSC neurons leading to saccadic eye movement requires collicular disinhibition, coupled with excitatory inputs from cortical areas. This cascade of disinhibition from the basal ganglia (BG) to the colliculus is proposed to gate cortical excitatory inputs to the colliculus encoding the location of salient objects in the visual field to guide the change in the line of sight. Recent evidence, however, suggests that the inhibition arising from the basal ganglia may play an active rather than a permissive role or “gating” in the generation of the command bursts in target structures such as the colliculus. We propose the hypothesis that rather than providing permissive disinhibition, BG inhibition alone is sufficient to drive the pre-movement spiking. To test this hypothesis, we performed viral injections carrying opsins labeled with GFP into the BG of mice and implanted a fiber optic probe into the deep layers of the SC to stimulate BG terminals. Opposite to the current model, light pulses evoked a rotating movement contralateral to the stimulating site in mice during an open field behavioral test. Patch-clamp recording of the collicular output neurons revealed that these presented a rebound depolarization (RD) at the end of current-triggered hyperpolarizations and these RDs were capable of triggering spike trains. These results allowed us to propose a more active role of the nigrocollicular pathway in the generation of orienting movement in mice.
Relevant Paper(s): https://www.jneurosci.org/content/6/3/723.long
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:
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)
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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