scholarly journals Neuronal Adaptation to the Value Range in the Macaque Orbitofrontal Cortex

2018 ◽  
Author(s):  
Katherine E. Conen ◽  
Camillo Padoa-Schioppa
Keyword(s):  
Orbitofrontal Cortex ◽  
Behavioral Context ◽  
Minimum Value ◽  
Economic Choice ◽  
Maximum Value ◽  
Baseline Activity ◽  
Subjective Value ◽  
Baseline Response ◽  
Value Range ◽  
Decision Circuit

AbstractEconomic choice involves computing and comparing the subjective values of different options. The magnitude of these values can vary immensely in different situations. To compensate for this variability, decision-making neural circuits adapt to the current behavioral context. In orbitofrontal cortex (OFC), neurons encode the subjective value of offered and chosen goods in a quasi-linear way. Previous work found that the gain of the encoding is lower when the value range is wider. However, previous studies did not disambiguate between neurons adapting to the value range or to the maximum value. Furthermore, they did not examine changes in baseline activity. Here we investigated how neurons in the macaque OFC adapt to changes in the value distribution. We found that neurons adapt to both the maximum and the minimum value, but only partially. Concurrently, the baseline response is higher when the minimum value is larger. Using a simulated decision circuit, we showed that higher baseline activity increases choice variability, and thus lowers the expected payoff in high value contexts.

scholarly journals Orbitofrontal cortex neurons code utility changes during natural reward consumption as correlates of relative reward-specific satiety

2020 ◽  
Author(s):  
Alexandre Pastor-Bernier ◽  
Arkadiusz Stasiak ◽  
Wolfram Schultz
Keyword(s):  
Orbitofrontal Cortex ◽  
Revealed Preference ◽  
Two Dimensional ◽  
Independent Manner ◽  
Preference Theory ◽  
Economic Choice ◽  
Subjective Value ◽  
Differential Reward ◽  
Specific Alteration ◽  
Differential Utility

AbstractNatural, on-going reward consumption can differentially reduce the subjective value (‘utility’) of specific rewards, which indicates relative, reward-specific satiety. Two-dimensional choice indifference curves (IC) represent the utility of choice options with two distinct reward components (‘bundles’) according to Revealed Preference Theory. We estimated two-dimensional ICs from stochastic choices and found that natural on-going consumption of two bundle rewards induced specific IC distortions that indicated differential reduction of reward utility indicative of relative reward-specific satiety. Licking changes confirmed satiety in a mechanism-independent manner. Neuronal signals in orbitofrontal cortex (OFC) that coded the value of the chosen option followed closely the consumption-induced IC distortions within recording periods of individual neurons. A neuronal classifier predicted well the changed utility inferred from the altered behavioral choices. Neuronal signals for more conventional single-reward choice options showed similar relationships to utility alterations from on-going consumption. These results demonstrate a neuronal substrate for the differential, reward-specific alteration of utility by on-going reward consumption reflecting reward-specific satiety.SignificanceRepeated delivery reduces the subjective value (‘utility’) of rewards to different degrees depending on their individual properties, a phenomenon commonly referred to as sensory-specific satiety. We tested monkeys during economic choice of two-component options. On-going consumption differentially reduced reward utility in a way that suggested relative reward-specific satiety between the two components. Neurons in the orbitofrontal cortex (OFC) changed their responses in close correspondence to the differential utility reduction, thus representing a neuronal correlate of relative reward-specific satiety. Control experiments with conventional single-component choice showed similar satiety-induced differential response reductions. These results are compatible with the notion of OFC neurons coding crucial decision variables robustly across different satiety levels.

scholarly journals Single-dimensional human brain signals for two-dimensional economic choice options

2020 ◽  
Author(s):  
Leo Chi U Seak ◽  
Konstantin Volkmann ◽  
Alexandre Pastor-Bernier ◽  
Fabian Grabenhorst ◽  
Wolfram Schultz
Keyword(s):  
Orbitofrontal Cortex ◽  
Brain Structures ◽  
Two Dimensional ◽  
Neural Signals ◽  
Economic Choice ◽  
Multiple Components ◽  
Brain Responses ◽  
Subjective Value ◽  
Behavioral Preferences ◽  
Value Coding

AbstractRewarding choice options typically contain multiple components, but neural signals in single brain voxels are scalar and primarily vary up or down. In a previous study, we had designed reward bundles that contained the same two milkshakes with independently set amounts; we had used psychophysics and rigorous economic concepts to estimate two-dimensional choice indifference curves (IC) that represented revealed stochastic preferences for these bundles in a systematic, integrated manner. All bundles on the same ICs were equally revealed preferred (and thus had same utility, as inferred from choice indifference); bundles on higher ICs (higher utility) were preferred to bundles on lower ICs (lower utility). In the current study, we used the established behavior for testing with functional magnetic resonance imaging (fMRI). We now demonstrate neural responses in reward-related brain structures of human female and male participants, including striatum, midbrain and medial orbitofrontal cortex that followed the characteristic pattern of ICs: similar responses along ICs (same utility despite different bundle composition), but monotonic change across ICs (different utility). Thus, these brain structures integrated multiple reward components into a scalar signal, well beyond the known subjective value coding of single-component rewards.Significance StatementRewards have several components, like the taste and size of an apple, but it is unclear how each component contributes to the overall value of the reward. While choice indifference curves of economic theory provide behavioural approaches to this question, it is unclear whether brain responses capture the preference and utility integrated from multiple components. We report activations in striatum, midbrain and orbitofrontal cortex that follow choice indifference curves representing behavioral preferences over and above variations of individual reward components. In addition, the concept-driven approach encourages future studies on natural, multi-component rewards that are prone to irrational choice of normal and brain-damaged individuals.

Physico-Chemical Characteristics of Sapota (Chikoo) Powder based Value Added Pasta Product using Semolina (Suji) and Maida

2020 ◽  
Vol 7 (04) ◽  
Author(s):  
SATYA NARAYAN SINGH ◽  
RAJESH G BURBADE ◽  
HITESH SANCHAVAT ◽  
P S PANDIT
Keyword(s):  
Bulk Density ◽  
Crude Protein ◽  
Water Solubility ◽  
Value Added ◽  
Absorption Capacity ◽  
Oil Absorption ◽  
Minimum Value ◽  
Maximum Value ◽  
Physico Chemical ◽  
Specific Length

The cereals of today are more nutritious and healthful than ever before. Cereals processing is one of the oldest and the most essential part of all food technologies. Pasta products and noodles have been staple foods since ancient times in many countries all over the world. In this study pasta formulation was substituted with blending sapota powder in different proportions (4 levels i.e. 0%, 10%, 20%, 30%) into semolina and maida flour separately. Pasta products were prepared using eight different formulations and adding water (approximately 31% of total weight) in DOLLY pasta extruder machine. All the samples were evaluated for physical properties: specific length (mm/g), bulk density (kg/m3), specific density (kg/m3) and porosity (%); functional properties: water absorption index (%), water solubility index (%) and oil absorption capacity (ml/g) and nutritional compositions: moisture (%), crude protein (%), fat (%) and carbohydrate (%). Highest specific length 36.20 mm/g was observed for T5 treatment, low bulk density 368.10 kg/m3 was observed for T5 and highest porosity 9.24% was found for T1 treatment. The maximum WAI, WSI values 325.83%, 17.33% respectively was observed for T1 treatment and minimum value of oil absorption capacity 1.06 ml/g for T8 treatment. The moisture content of dried pasta products was found in the range of 6 to 7%. The maximum value of crude protein 13.07% was found for T5 and minimum value 8.81% for T4 treatments. The fat contents were varied from 1.02% to 1.28 %. The maximum value of carbohydrate was 76.20% for T1 and minimum value 65.41% for T8.

scholarly journals Characteristic Variation of Ground Heat Flux and Net Radiation at Tropical Station in Ile-Ife, Osun State, Nigeria

2020 ◽  
pp. 35-42
Author(s):  
A. Usman ◽  
B. B. Ibrahim ◽  
L. A. Sunmonu
Keyword(s):  
Heat Flux ◽  
Research Work ◽  
Soil Heat Flux ◽  
Entire Period ◽  
Net Radiation ◽  
Sampled Data ◽  
Minimum Value ◽  
Maximum Value ◽  
Characteristic Variation ◽  
Ground Heat Flux

Characteristic variation of ground heat flux and net radiation enhances the understanding of the significance of indicated trends of variability to everyday life and factors that might be responsible for such variations. This research work critically analyses some specific days with field data over grass-covered surface at Ile-Ife, Nigeria between ground heat flux and net radiation. For the field observations, an instrumented meteorological mast was set up at an experimental site (7°33’N, 4°35’E) located at Obafemi Awolowo University campus, Ile-Ife, Nigeria for a period of two weeks (31st May-14th June, 2013). The soil heat flux, net radiation and soil temperature from the soil heat flux plate; an all-wave net radiometer, and soil thermometer were recorded every 10 seconds and averaged over 2 minutes interval. The sampled data was stored in the data logger (Campbell Scientific, Model CR10X) storage module. After the removal of spurious measurement values (Quality Assurance and Quality Control), the data stored was further reduced to 30 minutes averages using the Microcal Origin (version 7.0) data analysis software. The results showed that the measured ground heat flux, HGM during the daytime increases until 1400 hrs with maximum value of about 136.86 Wm-2 and minimum value of about -72.87 Wm-2 at 0830 hrs (DOY 156). The measured net radiation, Rn value of 649.65 Wm-2 observed at 1400 hrs (DOY 156), represented the maximum value for the entire period of the study. -10.75 Wm-2 value observed at1800 hrs (DOY 154), represented the minimum value for the entire period of the study due to the cloudy condition of the sky which reduces the amount of incoming solar radiation reaching the earth surface.

scholarly journals COMPARING THE FLEXURAL STRENGTH OF CONCRETE MADE WITH RIVER SAND WITH THAT MADE WITH QUARRY DUST AS FINE AGGREGATE

2018 ◽  
Vol 6 (6) ◽  
pp. 453-460
Author(s):  
Chijioke C ◽  
Nwaiwu ◽  
Aginam ◽  
Anyadiegwu
Keyword(s):  
Flexural Strength ◽  
Concrete Beams ◽  
Target Strength ◽  
Fine Aggregate ◽  
River Sand ◽  
Minimum Value ◽  
Maximum Value ◽  
Quarry Dust ◽  
Good Substitute

This work focuses on the 100% replacement of river sand with quarry dust in the production of concrete. Two types of concrete were produced (concrete made with river sand and that made with quarry dust as fine aggregate), the concretes produces were cast into beams and cured for 28 days. The flexural strengths of the concrete beams cast was determine at 28 day strength. At 28 days target strength the maximum flexural strength of concrete made with river sand as fine aggregate is 5.375111N/mm2 and minimum flexural strength is 2.2155N/mm2, for the concrete made with quarry dust as fine aggregate the maximum flexural strength is 2.567 N/mm2. The maximum value of 2.567 N/mm2 for concrete made with quarry dust as fine aggregate is higher than the minimum value of 2.2155N/mm2 for concrete made with river sand as fine aggregate. With this result it shows that quarry dust is a good substitute to river sand in the production of concrete.

scholarly journals THE EFFECT OF RECOMBINANT VASCULAR ENDOTHELIAL GROWTH FACTOR 121 ON NITRIDE OXIDE LEVEL IN MICE (Mus musculus) MODEL OF PREECLAMPSIA

2017 ◽  
Vol 53 (3) ◽  
pp. 191
Author(s):  
Soetrisno Soetrisno ◽  
Isharyadi Isharyadi ◽  
Sri Sulistyowati
Keyword(s):  
Nitric Oxide ◽  
Mus Musculus ◽  
P Value ◽  
Vascular Endothelial ◽  
The Third ◽  
Minimum Value ◽  
Maximum Value ◽  
Pregnant Mice ◽  
Endothelial Growth Factor ◽  
K2 Group

Preeclampsia is a multifactorial syndrome in pregnancy whose cause is still unknown. Several proangiogenic and antiangiogenic mediators such as Vascular Endothelial Growth Factor (VEGF) and Nitrite Oxide (NO) play important roles in preventing preeclampsia. VEGF can increase NO level that lowers maternal blood pressure, improves endothelial function and reduces placental hypoxia in preeclampsia. Recombinant VEGF 121 is expected to be an option in the prevention and treatment of preeclampsia. This experimental study used mice (Mus musculus) as the model. The objective of this study was to observe the effect of recombinant VEGF 121 in increasing the level of nitric oxide in mice (Mus musculus) model of preeclampsia. This was an experimental analytical study with Randomized Control Trial (RCT) design. The study enrolled 27 pregnant mice (Mus musculus) which met the restriction criteria divided into 3 groups. The first group (K1) were 9 normal pregnant mice. The second group (K2) were 9 pregnant mice of preeclampsia model without treatment. The third group (K3) were 9 pregnant mice of preeclampsia model receiving recombinant VEGF 121 therapy. The independent variable was the administration of recombinant VEGF 121 and the dependent variable was the serum NO level. Statistical analysis was performed by using anova statistics. NO level in the first group (K1) was 1.746±0.347, with minimum value of 1.00 µM, and maximum value of 2.28 µM, CI (1.479-2.013).  NO level in second group (K2) was 1.167±0.380, with minimum value of 0.64 µM, and maximum value of 1.94 µM, CI (0.875-1.460). NO level in the third group (K3) was 2.164±0.556, with minimum value of 1.56 µM, and maximum value of 5.96 µM, CI (1.842-2.486). With anova statistical test, there were significant differences between K1 group and K2 group (p value=0.004<0.05), K1 group and K3 group (p value=0.000<0.05) as well as K2 group and K3 group (p value=0.029<0.05). In conclusion, Recombinant VEGF 121 increased the level of nitric oxide in mice (Mus musculus) model of preeclampsia significantly.

Evolutionary Structural Optimization Using the Minor Value of Material Efficiency

2014 ◽  
Vol 945-949 ◽  
pp. 1223-1226
Author(s):  
Xing Guo Hu ◽  
He Ming Cheng
Keyword(s):  
Structural Optimization ◽  
Rejection Rate ◽  
Minimum Value ◽  
Optimization Result ◽  
Material Efficiency ◽  
Evolutionary Structural Optimization ◽  
Maximum Value ◽  
Two Factors

In the tradition Evolutionary Structural Optimization (ESO), the maximum value of inefficient material efficiency equates to the product of the rejection rate and the maximum value of all material efficiency. However, the rejection rate cannot be adjusted flexibly according to the trend of optimization, and the maximum value of all material efficiency may mutate abruptly (become larger or smaller). These two factors may cause that material may sometimes be removed less, sometimes too much. In view of the defect of the traditional evolutionary structural optimization, the Evolutionary Structural Optimization Using the Minor Value of Material Efficiency (ESO-MVME) is proposed in this paper. The maximum value of the inefficient material is close to the minimum value of material efficiency, and has nothing to do with the reject rate and the maximum value of material efficiency. The study finds that the ESO-MVME method has a better applicability than the traditional ESO, and can obtain a better optimization result.

ANALYSIS OF SURFACE ROUGHNESS AT OVERLAPPING LASER SHOCK PEENING

2016 ◽  
Vol 23 (03) ◽  
pp. 1650012 ◽  
Author(s):  
F. Z. DAI ◽  
Z. D. ZHANG ◽  
J. Z. ZHOU ◽  
J. Z. LU ◽  
Y. K. ZHANG
Keyword(s):  
Surface Roughness ◽  
Theoretical Analysis ◽  
Equilateral Triangle ◽  
Experimental Results ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Minimum Value ◽  
Maximum Value ◽  
Shock Peening ◽  
Iso 25178

The overlapping effects on surface roughness are studied when samples are treated by laser shock peening (LSP). Surface roughness of overlapped circular laser spot is calculated by ISO 25178 height parameters. The usually used overlapping styles namely isosceles-right-triangle-style (AAP) and equilateral-triangle-style (AAA) are carefully investigated when the overlapping degree in x-axis ([Formula: see text]) is below 50%. Surface roughness of isosceles-right-triangle-style attains its minimum value at [Formula: see text] of 29.3%, and attains its maximum value at [Formula: see text] of 43.6%. Surface roughness of equilateral-triangle-style attains its minimum value at [Formula: see text] of 42.3%, and attains its maximum value at [Formula: see text] of 32%. Experimental results are well consistent with theoretical analysis.

scholarly journals A vector loci method of treating coupled circuits

1928 ◽  
Vol 117 (777) ◽  
pp. 331-350 ◽  
Keyword(s):  
Electromotive Force ◽  
Complex Impedance ◽  
Variable Frequency ◽  
Constant Amplitude ◽  
Minimum Value ◽  
Maximum Value ◽  
Straight Line ◽  
Family Of Curves ◽  
Coupled Circuits ◽  
Zero Coupling

If in the first of two coupled circuits an electromotive force of constant amplitude and variable frequency is introduced, the currents in the primary and secondary respectively may be written i 1 = e /Z' and i 2 = e /Z" where Z' and Z" are complex impedance operators. The loci of these impedances ω as to is varied have definite geometrical forms. Z" is a parabola and Z' a cissoid family. If a parabola if y 2 = (— x ) p where p depends only on the inductances and resistances of the two circuits is drawn, and a pole O is taken a certain distance to the left of the vertex a , then OP represents the impedance Z" to a certain scale. The greater the coupling between the two circuits the longer is O a . As ω increases from a small value, P, starting on the lower arm of the parabola far to the left, moves counter clockwise round the parabola. If O is near a there will be a single minimum value of OP, and a single maximum value of the current i 2 . But if the coupling and therefore O a is larger, there will be two minimum values separated by a maximum value, corresponding to the well-known double hump i 2 /ω curve. The locus of Z' is the cissoid family of curves. The straight line of zero coupling bulges at the axis as the coupling is increased, and develops a loop as the coupling is still further increased. Here again a double minimum impedance appears, corresponding to the double hump resonance curves.

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