scholarly journals Glutamine-to-glutamate ratio in the nucleus accumbens predicts effort-based motivated performance in humans

2020 ◽  
Vol 45 (12) ◽  
pp. 2048-2057
Author(s):  
Alina Strasser ◽  
Gediminas Luksys ◽  
Lijing Xin ◽  
Mathias Pessiglione ◽  
Rolf Gruetter ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Resonance Spectroscopy ◽  
Social Competition ◽  
Ultra High Field ◽  
Physiological Processes ◽  
Incentive Value ◽  
Best Fitting ◽  
Overall Performance ◽  
And Performance ◽  
Model Based Analysis

Abstract Substantial evidence implicates the nucleus accumbens in motivated performance, but very little is known about the neurochemical underpinnings of individual differences in motivation. Here, we applied 1H magnetic resonance spectroscopy (1H-MRS) at ultra-high-field in the nucleus accumbens and inquired whether levels of glutamate (Glu), glutamine (Gln), GABA or their ratios predict interindividual differences in effort-based motivated task performance. Given the incentive value of social competition, we also examined differences in performance under self-motivated or competition settings. Our results indicate that higher accumbal Gln-to-Glu ratio predicts better overall performance and reduced effort perception. As performance is the outcome of multiple cognitive, motor and physiological processes, we applied computational modeling to estimate best-fitting individual parameters related to specific processes modeled with utility, effort and performance functions. This model-based analysis revealed that accumbal Gln-to-Glu ratio specifically relates to stamina; i.e., the capacity to maintain performance over long periods. It also indicated that competition boosts performance from task onset, particularly for low Gln-to-Glu individuals. In conclusion, our findings provide novel insights implicating accumbal Gln and Glu balance on the prediction of specific computational components of motivated performance. This approach and findings can help developing therapeutic strategies based on targeting metabolism to ameliorate deficits in effort engagement.

scholarly journals Interactive effects of incentive value and valence on the performance of discrete action sequences

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tyler J. Adkins ◽  
Bradley S. Gary ◽  
Taraz G. Lee
Keyword(s):  
Motor Learning ◽  
Large Body ◽  
Interactive Effects ◽  
Motor Tasks ◽  
Skill Retention ◽  
Incentive Value ◽  
Discrete Action ◽  
On Line ◽  
And Performance ◽  
Gains And Losses

AbstractIncentives can be used to increase motivation, leading to better learning and performance on skilled motor tasks. Prior work has shown that monetary punishments enhance on-line performance while equivalent monetary rewards enhance off-line skill retention. However, a large body of literature on loss aversion has shown that losses are treated as larger than equivalent gains. The divergence between the effects of punishments and reward on motor learning could be due to perceived differences in incentive value rather than valence per se. We test this hypothesis by manipulating incentive value and valence while participants trained to perform motor sequences. Consistent with our hypothesis, we found that large reward enhanced on-line performance but impaired the ability to retain the level of performance achieved during training. However, we also found that on-line performance was better with reward than punishment and that the effect of increasing incentive value was more linear with reward (small, medium, large) while the effect of value was more binary with punishment (large vs not large). These results suggest that there are differential effects of punishment and reward on motor learning and that these effects of valence are unlikely to be driven by differences in the subjective magnitude of gains and losses.

Behavior and Performance of Refrigerant Mixture HFC125/HC290 in Heat Pumps

2013 ◽  
Author(s):  
Xiaowei Fan ◽  
Fang Wang ◽  
Huifan Zheng ◽  
Xianping Zhang ◽  
Di Xu
Keyword(s):  
Energy Consumption ◽  
Heat Pumps ◽  
Operating Conditions ◽  
Environment Friendly ◽  
Factors Affecting ◽  
Refrigerant Mixture ◽  
Important Direction ◽  
Overall Performance ◽  
And Performance ◽  
Binary Refrigerant

The refrigerant mixtures provide an important direction in selecting new environment-friendly alternative to match the desirable properties with the existing halogenated refrigerants or future use in the new devices, in which, HFCs refrigerants with zero ODP combined with HCs refrigerants with zero ODP and lower GWP are of important value in the fields of application. In the present work, research on HFC125/HC290 (25/75 by mass) binary refrigerant mixture used in heat pumps was carried out, and parameters, factors affecting the performance were investigated, and compared with that of HCFC22 under the same operating conditions. It has been found that the new mixture can improve the actual COP by 2 to 13% and hence it can reduce the energy consumption by 20 to 31.5%. The overall performance has proved that the new refrigerant mixture could be a promising substitute for HCFC22.

scholarly journals Ultra-High-Field Magnetic Resonance Spectroscopy in Psychiatry

2017 ◽  
Vol 8 ◽  
Author(s):  
Beata R. Godlewska ◽  
Stuart Clare ◽  
Philip J. Cowen ◽  
Uzay E. Emir
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
High Field ◽  
Resonance Spectroscopy ◽  
Ultra High Field

Caffeine counteracts the ergogenic action of muscle creatine loading

1996 ◽  
Vol 80 (2) ◽  
pp. 452-457 ◽  
Author(s):  
K. Vandenberghe ◽  
N. Gillis ◽  
M. Van Leemputte ◽  
P. Van Hecke ◽  
F. Vanstapel ◽  
...  
Keyword(s):  
Intermittent Exercise ◽  
Creatine Supplementation ◽  
Knee Extensors ◽  
Caffeine Intake ◽  
Resonance Spectroscopy ◽  
Experimental Conditions ◽  
Before And After ◽  
And Performance ◽  
Exercise Fatigue ◽  
Voluntary Contractions

This study aimed to compare the effects of oral creatine (Cr) supplementation with creatine supplementation in combination with caffeine (Cr+C) on muscle phosphocreatine (PCr) level and performance in healthy male volunteers (n = 9). Before and after 6 days of placebo, Cr (0.5 g x kg-1 x day-1), or Cr (0.5 g x kg-1 x day-1) + C (5 mg x kg-1 x day-1) supplementation, 31P-nuclear magnetic resonance spectroscopy of the gastrocnemius muscle and a maximal intermittent exercise fatigue test of the knee extensors on an isokinetic dynamometer were performed. The exercise consisted of three consecutive maximal isometric contractions and three interval series of 90, 80, and 50 maximal voluntary contractions performed with a rest interval of 2 min between the series. Muscle ATP concentration remained constant over the three experimental conditions. Cr and Cr+C increased (P < 0.05) muscle PCr concentration by 4-6%. Dynamic torque production, however, was increased by 10-23% (P < 0.05) by Cr but was not changed by Cr+C. Torque improvement during Cr was most prominent immediately after the 2-min rest between the exercise bouts. The data show that Cr supplementation elevates muscle PCr concentration and markedly improves performance during intense intermittent exercise. This ergogenic effect, however, is completely eliminated by caffeine intake.

scholarly journals Development and Performance of the Pepper Industry in Malaysia: A Critical Review

2021 ◽  
Vol 21 (3) ◽  
pp. 1402-1423
Author(s):  
Harry Entebang ◽  
Swee-Kiong Wong ◽  
Zehnder Jarroop Augustine Mercer
Keyword(s):  
Rural Community ◽  
Household Income ◽  
New Technology ◽  
Supply And Demand ◽  
National Income ◽  
Secondary Data ◽  
Commodity Export ◽  
Overall Performance ◽  
And Performance ◽  
Farm Inputs

The National Commodity Policy 2011-2020 was developed to increase the national income by harnessing the potential of commodity export revenues. Despite continuous efforts implemented by various related agencies, the overall performance of major commodities, particularly pepper, remains unsatisfactory. Regarded as a sought-after ‘king of spices’, pepper has become one of the most prized and important commodities traded globally. This paper highlights the development and performance of the pepper industry in Malaysia and discusses practical strategies and recommendations to transform the pepper industry. Besides conducting interviews with the industry experts to gain first-hand information, content and thematic analysis was employed based on secondary data research in this study. The findings of the study show that even though pepper is mostly used in food-related industries, its potential in pharmaceutical and cosmeceutical sectors remains underexplored. Globally, the overall supply and demand of pepper continue to increase, though the demand has recently exceeded supply. However, continuous new planting and farmexpansion initiatives by major producers caused the total global pepper supply to exceed consumption in 2018. In fact, pepper prices have declined more than 70% since 2015, which affected the overall household income of the rural community engaged in pepper farming. While experiencing low prices, smallholder pepper farmers and the industry continue to struggle with low domestic consumption, low production, higher cost of farm inputs, lack of extension services, low impact of research, development and innovation, ageing farming population, intense competition from other producing countries, low prices for quality pepper, limited subsidy to support continuous farming, pepper-related diseases, lack of new technology, and poor investment in downstream activities. Given this, the performance of the Malaysian pepper industry has fallen below expectations.

scholarly journals VLSI ARCHITECTURE OF PARALLEL MULTIPLIER– ACCUMULATOR BASED ON RADIX-2 MODIFIED BOOTH ALGORITHM

2012 ◽  
pp. 40-46
Author(s):  
Mr.M.V. Sathish ◽  
Mrs. Sailaja
Keyword(s):  
Signal Processing ◽  
High Speed ◽  
High Performance ◽  
Vlsi Architecture ◽  
Clock Frequency ◽  
Parallel Multiplier ◽  
Hybrid Type ◽  
Standard Design ◽  
Overall Performance ◽  
And Performance

A new architecture of multiplier-andaccumulator (MAC) for high-speed arithmetic. By combining multiplication with accumulation and devising a hybrid type of carry save adder (CSA), the performance was improved. Since the accumulator that has the largest delay in MAC was merged into CSA, the overall performance was elevated. The proposing method CSA tree uses 1’s-complement-based radix-2 modified Booth’s algorithm (MBA) and has the modified array for the sign extension in order to increase the bit density of the operands. The proposed MAC showed the superior properties to the standard design in many ways and performance twice as much as the previous research in the similar clock frequency. We expect that the proposed MAC can be adapted to various fields requiring high performance such as the signal processing areas.

scholarly journals Early Phonological Neural Specialization Predicts Later Growth in Word Reading Skills

2019 ◽  
Author(s):  
Brianna L. Yamasaki ◽  
Karla Kay McGregor ◽  
James R. Booth
Keyword(s):  
Phonological Processing ◽  
Semantic Processing ◽  
Reading Skills ◽  
Word Reading ◽  
Superior Temporal Gyrus ◽  
Preliminary Evidence ◽  
Reading Growth ◽  
Best Fitting ◽  
And Performance ◽  
Performance Results

According to the Interactive Specialization Theory, cognitive skill development is facilitated by a process of neural specialization. In line with this theory, the current study investigated whether neural specialization for phonological and semantic processing at 5-to-6 years old was predictive of growth in word reading skills from 5-to-8 years old. Specifically, four regression models were estimated in which reading growth was predicted from: (1) an intercept-only model, (2) measures of semantic and phonological neural specialization, (3) performance on semantic and phonological behavioral tasks, or (4) a combination of neural specialization and behavioral performance. Results from the preregistered analyses revealed little evidence in favor of the hypothesis that early semantic and phonological skills predict growth in reading. However, results from the exploratory analyses, which included a larger sample, focused exclusively on the phonological predictors, and investigated relative growth in reading, demonstrated strong evidence that variability in phonological processing is predictive of growth in word reading skills. Specifically, the best fitting model included both measures of phonological neural specialization within the posterior superior temporal gyrus and performance on a phonological behavioral task. This work provides important preliminary evidence in favor of the Interactive Specialization Theory and, more specifically, for the role of phonological neural specialization in the development of early word reading skills.

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