Henri Temianka Correspondence; (miscellaneous)

This collection contains material pertaining to the life, career, and activities of Henri Temianka, violin virtuoso, conductor, music teacher, and author. Materials include correspondence, concert programs and flyers, music scores, photographs, and books.https://digitalcommons.chapman.edu/temianka_correspondence/3253/thumbnail.jp

The Neural Encoding of Reward in the Striatal-Pallidal Circuitry

Humans and animals are constantly exposed to external stimuli. The ability to process reward value of a stimulus is critical to guiding appropriate behavior and essential for survival. These processes are regulated by neuronal activity and neurochemical signaling in the reward circuitry, particularly in the nucleus accumbens (NAc). The NAc receives dopaminergic inputs from the midbrain ventral tegmental area (VTA) and sends GABAergic projections to the ventral pallidum (VP). Electrophysiological studies have characterized phasic neuronal responses in the NAc that differential encode appetitive and aversive taste stimuli. Exposure to an appetitive taste stimulus evoked predominantly phasic inhibitory responses in the NAc whereas a majority of responses to an aversive taste was excitation. The work presented here focused on investigating how activity in the NAc modulate reward encoding in downstream VP, and the role of dopamine signaling in regulating neuronal responses to reward in the NAc. Using electrophysiological recording techniques, we present evidence of neural encoding of reward information in the VP. VP neurons responded to appetitive and aversive taste stimuli with primarily inhibitory and excitatory responses, respectively. Furthermore, devaluation of the appetitive stimulus resulted from cocaine-induced taste aversion conditioning revealed that the encoding of sucrose shifted from inhibition to excitation, resembling that of an aversion response. These data suggest that the VP, similar to the NAc, also encode reward information neuronally. In a subsequent study, the influence of NAc on VP reward encoding was tested by pharmacologically manipulating activity in the NAc while monitoring the neuronal activity in the VP. We demonstrate that by inhibiting activity in the NAc with a GABAergic agonist, the neural encoding to sucrose in the VP was augmented, followed by increased sucrose consumption. These findings support the notion that at least some aspect of reward information processed in VP is modulated by NAc activity. In the final study, we show that chemogenetically suppressing activity of VTA dopamine neurons inverted the response profile to sucrose from inhibition to excitation in the NAc. This elimination of inhibitory reward encoding in the NAc was accompanied by a dampened motivational state, demonstrated by subjects terminating leverpress behavior for sucrose reward quicker in a progressive ratio test on day that dopamine signaling was chemogenetically suppressed but not in control condition. Taken together, results from these studies provide insights into how reward information is represented by physiological events in the reward circuitry. We demonstrate that neuronal responses in both the NAc and the VP encode reward and correlate strongly to reward-driven motivated behavior. Furthermore, we used a chemogenetic approach to show that suppressed NAc dopamine signaling models a low motivational state that is represented by altered neuronal responses in the NAc. This endeavor to better understand the neural representation of reward may help us better understand the physiology of both normal and diseased motivational and affective states

The Neural Encoding of Cocaine-Induced Devaluation in The Ventral Pallidum

Cocaine experience affects motivation structures such as the nucleus accumbens (NAc) and its major output target, the ventral pallidum (VP). Previous studies demonstrated that both NAc activity and hedonic responses change reliably as a taste cue comes to predict cocaine availability. Here we extended this investigation to examine drug-experience induced changes in hedonic encoding in the VP. VP activity was first characterized in adult male Sprague–Dawley rats in response to intraoral infusions of palatable saccharin and unpalatable quinine solutions. Next, rats received 7 daily pairings of saccharin that predicted either a cocaine (20 mg/kg, ip) or saline injection. Finally, the responses to saccharin and quinine were again assessed. Of 109 units recorded in 11 rats that received saccharin–cocaine pairings, 71% of responsive units significantly reduced firing rate during saccharin infusions and 64% increased firing rate during quinine exposure. However, as saccharin came to predict cocaine, and elicited aversive taste reactivity, VP responses changed to resemble quinine. After conditioning, 70% of saccharin-responsive units increased firing rate. Most units that encoded the palatable taste (predominantly reduced firing rate) were located in the anterior VP, while most units that were responsive to aversive tastes were located in the posterior VP. This study reveals an anatomical complexity to the nature of hedonic encoding in the VP

Interview by Chan Lung Kui Danny

Mr Wong is comes from an ordinary family in China, but something difference is that Mr Wong reads a lot of book at his early age. He read book because his mother teach him when he was not understand all things. Because his mother studied a lot of book from her parents, this is very unique that a woman can study at his mother\u27s century, something sorrowed in his father die when he is sever years old. So, he just live with his mother, grandmother and one elder sister, he said that his relationship between all his family members are very good. All concern with each other without many arguement, this also make him much influenced by his mother more than his father. Before his father die, his occupation is a doctor. Mr Wong also wishes to be a doctor when he was young, but when he grew up with experience the battle of Japanese, he change his wishes to be a soldier

Reduced Uncertainties in the Flutter Analysis of the Aerostructures Test Wing

Tuning the finite element model using measured data to minimize the model uncertainties is a challenging task in the area of structural dynamics. A test validated finite element model can provide a reliable flutter analysis to define the flutter placard speed to which the aircraft can be flown prior to flight flutter testing. Minimizing the difference between numerical and experimental results is a type of optimization problem. Through the use of the National Aeronautics and Space Administration Dryden Flight Research Center s (Edwards, California, USA) multidisciplinary design, analysis, and optimization tool to optimize the objective function and constraints; the mass properties, the natural frequencies, and the mode shapes are matched to the target data and the mass matrix orthogonality is retained. The approach in this study has been applied to minimize the model uncertainties for the structural dynamic model of the aerostructures test wing, which was designed, built, and tested at the National Aeronautics and Space Administration Dryden Flight Research Center. A 25-percent change in flutter speed has been shown after reducing the uncertaintie

Subspace Iteration Method for Complex Eigenvalue Problems with Nonsymmetric Matrices in Aeroelastic System

Modern airplane design is a multidisciplinary task which combines several disciplines such as structures, aerodynamics, flight controls, and sometimes heat transfer. Historically, analytical and experimental investigations concerning the interaction of the elastic airframe with aerodynamic and in retia loads have been conducted during the design phase to determine the existence of aeroelastic instabilities, so called flutter .With the advent and increased usage of flight control systems, there is also a likelihood of instabilities caused by the interaction of the flight control system and the aeroelastic response of the airplane, known as aeroservoelastic instabilities. An in -house code MPASES (Ref. 1), modified from PASES (Ref. 2), is a general purpose digital computer program for the analysis of the closed-loop stability problem. This program used subroutines given in the International Mathematical and Statistical Library (IMSL) (Ref. 3) to compute all of the real and/or complex conjugate pairs of eigenvalues of the Hessenberg matrix. For high fidelity configuration, these aeroelastic system matrices are large and compute all eigenvalues will be time consuming. A subspace iteration method (Ref. 4) for complex eigenvalues problems with nonsymmetric matrices has been formulated and incorporated into the modified program for aeroservoelastic stability (MPASES code). Subspace iteration method only solve for the lowest p eigenvalues and corresponding eigenvectors for aeroelastic and aeroservoelastic analysis. In general, the selection of p is ranging from 10 for wing flutter analysis to 50 for an entire aircraft flutter analysis. The application of this newly incorporated code is an experiment known as the Aerostructures Test Wing (ATW) which was designed by the National Aeronautic and Space Administration (NASA) Dryden Flight Research Center, Edwards, California to research aeroelastic instabilities. Specifically, this experiment was used to study an instability known as flutter. ATW was a small-scale airplane wing comprised of an airfoil and wing tip boom. This wing was formulated based on a NACA-65A004 airfoil shape with a 3.28 aspect ratio. The wing had a span of 18 inch with root chord length of 13.2 inch and tip chord length of 8.7 inch. The total area of this wing was 197 square inch. The wing tip boom was a 1 inch diameter hollow tube of length 21.5 inch. The total weight of the wing was 2.66 lbs

Properties of beta-propeller phytase expressed in transgenic tobacco

Phytases are enzymes that liberate inorganic phosphates from phytate. In a previous study, a beta-propeller phytase (168phyA) from Bacillus subtilis was introduced into transgenic tobacco, which resulted in certain phenotypic changes. In the study described herein, the recombinant phytase (t168phyA) was purified from transgenic tobacco to near homogeneity by a three-step purification scheme. The biochemical properties and kinetic parameters of t168phyA were compared with those of its counterpart from B. subtilis. t168phyA was glycosylated, and it showed a 4 kDa increase in molecular size in SDS-PAGE (44 kDa vs. 40 kDa). Although its thermostability remained unchanged, its temperature optimum shifted from 60°C to 45-50°C and its pH optimum shifted from pH 5.5 to 6.0. Kinetic data showed that the t168phyA had a lower Kcat, but a higher Km than the native enzyme. Despite these changes, t168phyA remained catalytically active and has a specific activity of 2.3 U/mg protein. These results verify the activity of recombinant Bacillus phytase that is expressed in plants. © 2005 Elsevier Inc. All rights reserved.postprin