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Summer 2010:

June (Summer)

Jun 25th

Cortical methylation maintains remote memory

Speaker: Justin Shobe

Summary of the talk:

Relevant Paper :

Paper 1



July


Jul 09th

Activity-dependent nuclear translocation from synapse to nucleus of the Transducer of Regulated CREB 1(TORC1)/CREB Regulated Transcriptional Co-activator 1 (CRTC1)

Speaker : Kelsey Martin

Summary of the talk :

Relevant Paper :

[Work from her lab]



Jul 30th

Metaplasticity at Single Synapses

Speaker: Adam Frank

Summary of the talk: Neuronal activity is known to modify NMDA receptor subunit composition; and, NMDAR subunit composition has significant effects on NMDAR synaptic currents. Given the importance of the NMDAR in the induction of LTP it is not surprising that altering NMDAR currents, by altering subunit composition, has demonstrated effects on the induction of LTP. Lee et al. now demonstrate these phenomena at the level of single synapses in cultured hippocampal neurons: altering spontaneous activity changes the ratio of NR2B to NR2A subunits and effects both NMDAR synaptic current as well as LTP induction threshold. These findings are presented in the context of metaplasticity, where prior activity at a synapse effects the subsequent ability of the synapse to undergo plasticity.

Relevant Paper :

Paper 1

Supplementary Info



August


Aug 06th

The reorganization and reactivation of hippocampal maps predict spatial memory performance

Speaker: Walt Babiec

Summary: The hippocampus has place cells that preferentially fire at a particular location of spatial arena. Dupret et al. report that place fields remapped as a result of goal-directed spatial learning and that sharp wave/ripple reactivation events seen during memory consolidation predicted the strength of subsequent spatial memory.

Relevant Paper :

News and Views

Paper

Supplementary Info


Aug 13th

Lateral and laminar flow of information in cortical circuits.


Speaker: Dean Buonomano

Summary: The basic flow of activity through cortical circuits is not understood, nor is the computational function of each step in the cortical circuit. It is known that lateral interactions play two critical roles: sharing information between neighboring areas and, conversely, competition through lateral inhibition. This paper from the Scanziani lab shows that both lateral competition and facilitation can be observed in vivo and in vitro.


Relevant Paper:

Paper



Aug 20th

BDNF substitutes for fear extinction


Speaker: Ravi Ponnusamy

Summary: Not provided


Relevant Paper:

Paper



Aug 27th

GABA is it purely inhibitory

Speaker : Shlomo Dellal

Summary: GABA is generally regarded as an inhibitory neurotransmitter in the adult CNS. However, in recent years, an excitatory role for GABA has been found in several brain regions. In this week’s LMP journal club, Shlomo Dellal will discuss a paper from the Rusakov and Kullman laboratories, in which they report that δ subunit containing GABAA receptors are expressed in presynaptic hippocampal mossy fiber boutons, where they enhance synaptic transmission and can facilitate LTP induction.

Relevant Paper:

Paper_1 Supp


September


Sep 03rd

Integrating dorsal and ventral hippocampus

Speaker : Gina Rinetti

Summary:Although the anatomical structure of the hippocampus is preserved along its septo-temporal axis, increasing evidence suggests that the septal (dorsal) and temporal (ventral) regions have different functions and project to different structures. Importantly, most studies focus on specific physiological aspects of the hippocampus such as learning and memory, LTP, space recognition (place cells, grid cells, etc), or emotion without integrating the findings within an anatomical context. Royer et al., J neuroscience 2010 (original paper) and Fanselow and Dong, Neuron 2010 (review), have been able to reconcile many of these functions in an elegant anatomical model.

My talk will focus mainly on the paper by Royer et al., in which the authors characterize the striking differences between place cells in dorsal and ventral CA3 areas. In general, dorsal pyramidal neurons are able to represent the environment better and display more precise temporal dynamics, compared to ventral pyramidal cells. An examination of these findings will be discussed in the context of hippocampal anatomy and integrative physiology. This discussion will be complemented with some examples from Fanselow and Dong.


Relevant Paper:

Paper 1 Paper 2



Sep 09th

The role of SIRT1 in memory formation and synaptic plasticity

Speaker: Marwan Maalouf

Summary:

The role of the histone deacetylase Sirt1 in brain aging and neurodegeneration has been widely documented but its involvement in cognitive functions is unknown. In the article entitled "A novel pathway regulates memory and plasticity ia SIRT1 and miR-134", Gao et al (2010) report that Sirt1 activation enhances memory formation and synaptic plasticity. The authors attribute the effects of Sirt1 to a microRNA-mediated mechanism. Specifically, they demonstrate that increased expression of the microRNA miR-134 in mice lacking Sirt1 catalytic activity downregulates the expression of CREB and BDNF, two factors that are critical for memory formation and synaptic plasticity.



Relevant Paper:

Paper 1 Supplement



Sep 17th

PKM zeta maintains memories by regulating GluR2-dependent AMPA receptor trafficking

Speaker: Michael Condro

Summary: PKMzeta is a PKC isoform that is both necessary and sufficient for late maintenance of LTP. Inactivation of this molecule can reverse LTP and abolish memory in some brain regions. This paper looks deeper into the mechanism by which PKMzeta maintains LTP.

Relevant Paper:

Paper 1


Sep 24th

Gilgamesh Is Required for Olfactory Conditioning in Drosophila

Speaker: Adam Roberts

Summary: Work on olfactory conditioning in Drosophila has succeeded in identifying several molecules, such as CREB, that have proved to be generally important in learning and memory (Davis, 2005). Recent work by Tan et al., 2010 has identified a novel mutant, gilgamesh (gish); the normal allele of the gish gene encodes casein kinase Ig and is required for olfactory conditioning. Memory impairments in the gish mutant appear to be independent of those previously observed in dunce and rutabaga mutants, which have deficits in cAMP signaling. This is the first paper demonstrating a role for casein kinase I in learning and memory.


Relevant Paper:

Paper 1


October


1stOct

Synaptic Estrogen Synthesis in the Hippocampus: a role in L and M

Speaker: Barney Schlinger

Summary: We have considerable evidence that estrogens are naturally formed at the synapse in many neural circuits, including in the hippocampus. Synaptic estrogen synthesis is rapidly modulated and formed estrogens in turn rapidly alter neuronal firing rates and behavior. I will review our studies using in vivo microdialysis and electrophysiological measures of auditory processing circuits in songbirds and discuss these findings in the context of the hippocampus of bird species that naturally perform hippocampal-based food caching and retrieval.


Relevant Information: Lab Webpage


8thOct

The role of PKM in maintaining long-term memory in Aplysia

Speaker: David Glanzman

Summary: Data from his lab


Oct 15th

Title :Role of secondary sensory cortices in emotional memory storage and retrieval in rats

Speaker: Thomas Rogerson

Summary: will be reviewing the paper “Role of secondary sensory cortices in emotional memory storage and retrieval in rats” (attached). This paper investigates the role of secondary sensory cortices in cued-fear memory and concludes that they are needed for remote but not recent memory. I will suggest that this dependence on cortical regions for the remote storage of cued-fear memory maybe partially analogous to systems consolidation of declarative memories from the hippocampus to the cortex. Also these findings implicate sensory cortices in more than perception thereby reaffirming the representational view of brain organization.


Relevant Information: Paper_1

Supp


Oct 29th

Title :

Speaker: Dr. Sandra Pena de Ortiz


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November

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Nov 5th

Title: “A Role for the Ubiquitin-Proteasome System in Activity-Dependent Presynaptic Silencing.”

Speaker: Kate Fehlhaber

Summary:The (re-)discovery of silent synapses took place amidst a debate over whether the locus of long-term potentiation (LTP) expression was a pre- or postsynaptic phenomenon. Results from subsequent research seemed contradictory, as different measures of quantal content seemed to yield opposite results. These observations were crucial to the realization that some unmeasured phenomenon must alter the perception of quantal content, namely silent (deaf) synapses! While their discovery did not quell the debate, their characterization has highlighted the role of AMPA receptor (AMPAR) trafficking in synaptic plasticity.

It has been shown that the proteasome regulates postsynaptic function, including AMPARs and PSD-95, but little is known about how the Ubiquitin-Proteasome System (UPS) affects presynaptic function. This paper by Jiang et al. explores the UPS in relation to presynaptic silencing (mute synapses), in which neurons exhibit reduced glutamate release after a period of increased spiking of tonic depolarization. Their findings demonstrate that modulation of the presynaptic proteasome complex by electrical activity governs glutamate release through control of key vesicle priming proteins. Their results represent one more clue into the debate over the exact mechanisms of LTP and provide further support for an important role of the UPS for synaptic plasticity.

Relevant Information: Paper_1


Previous Semesters

Spring 2010

Fall 2009