Seeing and controlling information flow through GTPase networks
Klaus Hahn (University of North Carolina, NC, USA)
Signaling proteins can produce essentially opposite cell behaviors depending on subtle differences in activation kinetics or transient localizations. To understand signaling controlled by spatio-temporal dynamics we have devised approaches to visualize and manipulate signaling networks in living cells and animals, including what we believe are broadly applicable methods to control proteins with light. The role of Rho family GTPase circuits in regulating motility is being probed using engineered allosteric switches to photoinhibit or photoactivate guanine exchange factors, kinases, and GTPases. Success with three different protein families leaves us optimistic that there is a simple way to identify and control allosteric networks with light or small molecules. LOVTRAP, a method for light-controlled sequestration and release of proteins, will also be described. LOVTRAP has been applied to modulate and dissect oscillating cellular circuits
Vendredi 9 septembre 2016 à 11h30, Salle de conférence.
Event-related brain potential (ERP) evidence for Immedicacy, Incrementality, prediction, and the role of context
Marta Kutas (University of California San Diego, CA, USA)
Significant neuro-cognitive work takes place at the language-memory interface that supports word and sentence processing. Both the content and the functional organization of our knowledge influence language comprehension in real time. Each cerebral hemisphere seems to be involved, albeit in different ways. The nature of the functional organization of our knowledge (associative, categorical, events, perceptuo-motor) and their use in predictive and/or integrative language processing have been revealed via investigations employing event-related brain potentials (ERPs). I will review some of our electrophysiological work supporting the idea that language processing is immediate and incremental, context-driven, sometimes predictive, multi-modal, and bi-hemispheric.
Vendredi 16 septembre 2016 à 11h30, Salle de conférence.
Probing Visual Perception Outside of Conscious Awareness
Randolph Blake (Vanderbilt University, TN, USA)
Conscious visual awareness seems to occupy center stage in our perceptual world, guiding our actions and channeling our thoughts. But is that impression a misleading illusion? To rephrase the question in a tractable form, what aspects of visual processing transpire outside of awareness? Psychologists have at their disposal an arsenal of techniques for dissociating optical input and visual awareness, and my talk will touch on the strengths and weaknesses of some of those techniques. But I’ll focus primarily on the beguiling phenomenon called binocular rivalry, wherein perceptual dominance fluctuates between conflicting visual images presented separately to the two eyes. I will highlight some surprising discoveries that have been made using rivalry to dissociate physical stimulation from perceptual awareness, including the impact of affective and semantic content on suppression of a stimulus from awareness. I will close by describing results illuminating possible neural concomitants of fluctuations in visual perception during rivalry and will offer some thoughts on the implications of those results for the larger question of neural correlates of consciousness
Vendredi 23 septembre 2016 à 11h30, Salle de conférence.
Programming the Cerebral Cortex: from Cortical Development to Cortex in the Dish
Paola Arlotta (Harvard Stem Cell Institute, MA, USA)
The neocortex contains an unparalleled diversity of neuronal subtypes, each defined by distinct traits that are developmentally acquired under the control of several neuron subtype-specific and pan-neuronal genes. The regulatory logic that orchestrates the coordinated expression of these unique combinations of genes is not known for any class of cortical neurons. I will discuss recent work on the identification of novel transcriptional dynamics underlying developmental generation of excitatory pyramidal neuron diversity in the cerebral cortex, and highlight some new governing principles that regulate interactions among pyramidal neuron classes, with a particular emphasis on oligodendrocytes and regulation of myelination. Finally, I will discuss new work aimed at modeling development and disease of the human cerebral cortex, in 3D cerebral organoids generated from human pluripotent stem cells
Vendredi 30 septembre 2016 à 11h30, Salle de conférence.
Unraveling the role of C-fibers in responding to inflammatory and nutritional challenges
Laurent Gautron (University of Texas Southwestern Medical Center, USA)
Physiological homeostasis is monitored and maintained by a complex system of neurons, including peripheral sensory neurons, which convey information from metabolic tissues to the brain. Of particular importance are Nav1.8-expressing afferents (C-fibers) which serve as a critical link between peripheral nutrient sensing and centrally mediated physiological responses. My laboratory is interested in the physiological requirements for Nav1.8-expressing neurons in regulating metabolic inflammation. Furthermore, we examine how inflammatory insults and high-fat feeding affects the anatomical integrity of Nav1.8-expressing neurons supplying the gastrointestinal tract, with a special emphasis on the role played by bacterial endotoxins and the Toll-like receptor 4. Together, these studies will increase our understanding of the biological control of energy balance, feeding and metabolic inflammation and will provide mechanistic insights to the pathophysiology of obesity-associated neuropathies
Vendredi 7 octobre 2016 à 11h30, Salle de conférence.
Putting sensory back into voluntary control
Stephen Scott (Queen’s University, Canada)
Optimal feedback control can explain many features of biological movement, such as success with variability, motor synergies and goal-directed behavior. The lecture will describe the use of optimal control to interpret motor performance, highlighting the importance of sensory feedback in this process. My talk will highlight how simple mechanical disturbances applied to the limb can uncover a range of sophisticated feedback processes, including knowledge of limb mechanics, scaling to spatial target location, avoidance of obstacles and selection of alternate goals. As well, I will highlight how sensory and motor cortices participate in this online control
Vendredi 4 novembre 2016 à 11h30, Salle de conférence.
titre à venir
Till Marquardt (European Neuroscience Institute Göttingen, Germany)
Vendredi 25 novembre 2016 à 11h30, Salle de conférence.
Is it time for immunopsychiatry?
Marion Leboyer (Institut Mondor, Créteil, France)
Vendredi 2 décembre 2016 à 11h30, Salle de conférence.
From exploration to fixation: how eye movements determine what we see
Susana Martinez-Conde (State University of New York, USA)
Vision depends on motion: we see things either because they move or because our eyes do. What may be more surprising is that large and miniature eye motions help us examine the world in similar ways - largely at the same time. In this presentation, I will discuss recent research from my lab and others suggesting that exploration and gaze-fixation are not all that different processes in the brain. Our eyes scan visual scenes with a same general strategy whether the images are huge or tiny, or even when we try to fix our gaze. These findings indicate that exploration and fixation are not fundamentally different behaviors, but rather two ends of the same visual scanning continuum. They also imply that the same brain systems control our eye movements when we explore and when we fixate - an insight that may ultimately offer clues to understanding both normal oculomotor function in the healthy brain, and oculomotor dysfunction in neurological disease
Vendredi 9 décembre 2016 à 11h30, Salle de conférence.