Adaptive Robotic Control Driven by a Versatile Spiking Cerebellar Network

The cerebellum is involved in a large number of different neural processes, especially in associative learning and in fine motor control. To develop a comprehensive theory of sensorimotor learning and control, it is crucial to determine the neural basis of coding and plasticity embedded into the cerebellar neural circuit and how they are translated into behavioral outcomes in learning paradigms. Learning has to be inferred from the interaction of an embodied system with its real environment, and the same cerebellar principles derived from cell physiology have to be able to drive a variety of tasks of different nature, calling for complex timing and movement patterns. We have coupled a realistic cerebellar spiking neural network (SNN) with a real robot and challenged it in multiple diverse sensorimotor tasks. Encoding and decoding strategies based on neuronal firing rates were applied. Adaptive motor control protocols with acquisition and extinction phases have been designed and tested, including an associative Pavlovian task (Eye blinking classical conditioning), a vestibulo-ocular task and a perturbed arm reaching task operating in closed-loop. The SNN processed in real-time mossy fiber inputs as arbitrary contextual signals, irrespective of whether they conveyed a tone, a vestibular stimulus or the position of a limb. A bidirectional long-term plasticity rule implemented at parallel fibers-Purkinje cell synapses modulated the output activity in the deep cerebellar nuclei. In all tasks, the neurorobot learned to adjust timing and gain of the motor responses by tuning its output discharge. It succeeded in reproducing how human biological systems acquire, extinguish and express knowledge of a noisy and changing world. By varying stimuli and perturbations patterns, real-time control robustness and generalizability were validated. The implicit spiking dynamics of the cerebellar model fulfill timing, prediction and learning functions.European Union (Human Brain Project) REALNET FP7-ICT270434 CEREBNET FP7-ITN238686 HBP-60410

FLUORESCENCE SPECTROSCOPY AND RADIATIONLESS PROCESSES IN CF3NOCF_{3}NO

This work is supported by the National Science Foundation.Author Institution: Department of Chemistry, Northwestern UniversityThe $CF_{3}NO$ molecule is a blue gas with a weak absorption from 520 to 720 nm that occurs by the promotion of a nitrogen nonbonding electron to the NO antibonding orbital. We have measured the collision free fluorescence lifetime with a tunable mode-locked, cavity dumped dye laser and find lifetimes that range from 90 to 0.2 nsec as a function of vibrational level. The excited state is vibrationally relaxed by collision and our initial comparisons of high pressure excitation spectra with absorption spectra suggest that photodissociation is probably occurring by both a rapid predissociative channel and another channel such as internal conversion or intersystem crossing. We will present time and wavelength resolved fluorescence spectra, high resolution laser excitation spectra and photochemical evidence to refine the excited state vibrational assignments and mechanisms for excited state relaxation

ANALYSIS OF THE TORSIONAL LEVELS IN TWO STATES OF CF3NO∗CF_{3}NO^{*}

$^{*}$Supported by the National Science FoundationAuthor Institution:The $CF_{3}NO$ molecule is a blue gas with a weak absorption from 520 to 720 nm that occurs by the promotion of a nitrogen nonbonding electron to the No antibonding orbital. We report on analysis of the torsional levels of the ground state and first excited singlet state of $CF_{3}NO$. The energies of the torsional quanta and barrier heights were by analysis of laser excited fluorescence emission and fluorescence excitation spetra. The excited electronic state exists as a single conformer in the straggered configuration and the overall transition from the eclipsed ground state to staggered excited state yields extensive overlapping absorption structure that is analyzed by fluorescence. The fluorescence lifetimes depend on the torsional level because of a competing radiationless process and we comment on the torsional dependence of this process

The Effects of Japanese Exports on Wholesale Beef and Live Cattle Prices

Has the rapid growth in the exports of wholesale beef affected U.S. beef and cattle prices? The short-term impact of U. S. beef exports to Japan, the dominant export destination, is estimated via econometric analysis of the relationship between monthly wholesale beef prices and export volumes of wholesale cuts to Japan. Rib and loin prices were signifcantly affected by Japanese exports, and the multiplier effects on U.S. cattle prices were higher than anticipated