לוח שנה משולב

This talk will consider the problem of sensorimotor co-ordination in mammals through the lens of vibrissal touch, and via the methodology of embodied computational neuroscience—using biomimetic robots to synthesize and investigate models of mammalian brain architecture. I will consider five major brain sub-systems from the perspective of their likely role in vibrissal system function—superior colliculus, basal ganglia, somatosensory cortex, cerebellum, and hippocampus. With respect to each of these sub-systems, the talk will illustrate how embodied modelling has helped elucidate their likely function in the brain of awake behaving animals, and will demonstrate how the appropriate co-ordination of these sub-systems, within a model of brain architecture, can give rise to integrated behaviour in life-like whiskered robots.

Race, Class and Affirmative Action, by Prof. Sigal Alon (The Russell Sage Foundation, 2015) evaluates the ability of class-based affirmative action to promote the social and economic mobility of disadvantaged populations and boost diversity at selective postsecondary institutions, as compared with race-based policy. The book draws from within- and between-country comparisons of several prototypes of affirmative action policy. It uses the United States as a case study of race-based preferences, and Israel as a case study of class-based preferences. For each country the model that has actually been implemented is compared to a simulated scenario of the alternative policy type. This develops new, and more global insights about the potential of race-neutral public policy to promote equality in higher education.

Voltage gated ion channels gate in response to changes in the electrical membrane potential by the coupling of a voltage sensitive paddle module with an ion-selective pore. Toxins that target these channels are traditionally classified as either pore-blockers or gating-modifiers, the former bind and physically occlude the channel pore, while the later bind the paddle module and restrict its movement in response to alterations in the membrane potential. During my talk, I would present a toxin derived from a cone-snail venom, exhibiting a novel allosteric action mechanism which seem to defy this traditional classification.

Animal ability to effectively locate and navigate towards food sources is central for survival. Here, using C. elegans nematodes, we revealed a previously unknown mechanism underlying efficient navigation in chemical gradients. This mechanism relies on the orchestrated dynamics of two types of chemosensory neurons: one coding gradients via stochastic pulsatile dynamics, and the second coding the gradients deterministically in a graded manner. The pulsatile dynamics obeys a novel principle where the activity adapts to the magnitude of the gradient derivative, allowing animals to take trajectories better oriented towards the target. The robust response of the second neuron to negative derivatives promotes immediate turns, thus alleviating costs of erroneous turns possibly incurred by the first neuron. This mechanism empowers an efficient navigation strategy which outperforms the classical biased-random walk strategy. Importantly, this mechanism is generalizable and other sensory modalities may use similar principles for efficient gradient-based navigation.

Proximal metallic and semiconductor nanocrystals can interact in various ways. Time-resolved photoluminescence allows to address interaction dependeces, which happen on picosecond timescales. We were able to reveal an unanticipated dependence on the gold nanoparticle size.
Looking deeper into the gold afterwards leads to the plasmon dynamics, for example hot-electron generation, which is happening faster than picoseconds. We found dependences of the hot electron generation on the excitation conditions which will allow more systematic studies of the plasmon-assisted catalysis