来る７月２２日水曜日の午後１時半より、下記の要領で、所長招聘セミナーと部門公開セミナーとして、４名の先生方に講演を連続でお願いしました。演者は、 IUPS2009や京都大学国際シンポジウムでの講演の為に来日されている先生方を初めとする最先端のお仕事をされている方々です。非常に興味深いお話をしていただけると思います。ご興味ある方は、ぜひ参加していただけますようよろしくお願いします。

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部門公開セミナー  13:30-14:20
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Glycoprotein-deficient rabies virus vector

Takuma Mori and Edward Callaway
Salk Institute for Biological Studies, La Jolla, U.S.A.

We have developed recombinant rabies viruses that can express various transgenes and are therefore useful for linking together cell types, connectivity, and function. By introducing the coding sequence for other genes (than GFP) into the genome of the glycoprotein-deleted rabies virus, we have created additional vectors with further utility. New recombinant rabies viruses include one encoding an epitope-tagged red fluorescent protein mCherry-myc (SAD-delta;G-mCherry-myc), and another encoding the troponin C based calcium biosensor TN-XL (SAD-delta;G-TN-XL). Both viruses can be used as described previously for GFP expressing virus, to label specific types of projection neurons. The SAD-ΔG-mCherry-myc virus has the additional advantage that it can be used in combination with GFP expressing transgenic mice or viral vectors. The SAD-delta;G-TN-XL virus can be used not only to visualize the morphology of neurons as finely as with SAD-delta;G-GFP, but it would also allow optical monitoring of the activity of specific projection neurons or interconnected populations. These new rabies viral vectors will therefore enable us to understand morphological and physiological aspects of neural circuits at a finer scale.
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所長招聘セミナー   14:20-15:20
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DENDRITIC LOCATION AFFECTS SYNAPTIC INTEGRATION AND PLASTICITY VIA MULTIPLE MECHANISMS IN HIPPOCAMPAL CA1 PYRAMIDAL NEURONS

Nelson Spruston, Dan Nicholson, Yael Katz, Vilas Menon, Jason Hardie
Dept. Neurobiology & Physiology, Northwestern University, Evanston, U.S.A

Excitatory synapses contact the dendrites of hippocampal CA1 pyramidal neurons at a variety of locations. We have used a combination of patch-clamp recording in hippocampal slices, serial-section electron microscopy, and immunogold localization of AMPA and NMDA receptors to study the properties of these synapses in different dendritic domains of CA1 neurons. We have also used computational modeling to develop testable predictions concerning how inputs onto these dendritic domains are integrated and converted to output (action potential firing in the axon) and used patch-clamp recording to understand the mechanisms responsible for dendritic integration and plasticity in these neurons. This lecture will describe the results of several studies that have led to a working model of synaptic integration and plasticity in CA1 pyramidal neurons. Specifically, we will present evidence that synaptic specializations and voltage-gated channels in CA1 dendrites are critical for ensuring that synapses on disparate dendritic domains can contribute to output via the axon and that some combinations of inputs are particularly effective for driving action potential firing or synaptic plasticity in these neurons.

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Coffee break            15:20-15:40
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所長招聘セミナー   15:40-16:40
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Dendritic processing in neocortical pyramidal neurons

Jackie Schiller
Dept. of Physiology, Bruce Rappaport Faculty of Medicine, The Technion, Israel

The layer-5 pyramidal neuron receives information from all cortical layers through its elaborated dendritic arborization and conveys the main output of the cortical hemisphere. Understanding the way this neuron is integrating its vast synaptic inputs is fundamental to understanding sensory-motor processing in the cortex. More than 80% of synapses contact the fine dendrites of the tree. In the past decade direct patch-clamp recordings were routinely performed from thicker portions of the dendritic tree. In this talk I will present data from our direct recordings in the fine dendrites of the tree. The integrative properties and plasticity rules will be presented with special emphasis on the importance of NMDA spikes.

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部門公開セミナー    16:40-17:30
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Top-down inputs drive large dendritic activity with animal behavior

Masanori Murayama
Institute of Physiology, Bern University, Bern, Switzerland

Very little is known about dendritic activity in awake animals and even less about its relationship to behavior. Anatomical and physiological studies have shown that top-down inputs, vital to awake behavior, projects to the upper layers of the cortex where it can synapse onto the tuft dendrites of pyramidal neurons. Here, we measured dendritic calcium activity in layer 5 (L5) pyramidal neurons in the sensorimotor cortex of awake and anesthetized rats following sensory stimulation by using a fiberoptics imaging method. Dendrites of L5 pyramidal cells were bolus-loaded with Oregon Green 488 BAPTA-1 AM. Bi-phasic dendritic responses evoked by hindlimb stimulation were extremely dependent on brain state. In the awake state, there was a prominent slow, delayed response whose integral was ~14 fold larger than in the anesthetized state. These changes were confined to L5 pyramidal dendrites and were not reflected in the activity of layer 2/3 neurons in general. Inacti  vating a higher cortical brain area, the supplementary motor area (SMA), with tetrodotoxin suppressed dendritic activity as did transecting the region between the two cortical areas. Conversely, stimulation of the same region resulted in increases in dendritic activity. Anterogradely labeling of L5 neurons with a neural tracer in the SMA showed corticocortical projections to primary sensory area. These physiological and anatomical findings demonstrate the SMA drives the large dendritic activity in sensory area. We conclude that during the awake state, top-down connections control the duration of dendritic activity which is functionally related to behavior.
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