Differences in Discounting Behavior and Brain Responses for Food and Money Reward.

Most neuroeconomic research seeks to understand how value influences decision-making. The influence of reward type is less well understood. We used functional magnetic resonance imaging (fMRI) to investigate delay discounting of primary (i.e., food) and secondary rewards (i.e., money) in 28 healthy, normal-weighted participants (mean age = 26.77; 18 females). To decipher differences in discounting behavior between reward types, we compared how well-different option-based statistical models (exponential, hyperbolic discounting) and attribute-wise heuristic choice models (intertemporal choice heuristic, dual reasoning and implicit framework theory, trade-off model) captured the reward-specific discounting behavior. Contrary to our hypothesis of different strategies for different rewards, we observed comparable discounting behavior for money and food (i.e., exponential discounting). Higher k values for food discounting suggest that individuals decide more impulsive if confronted with food. The fMRI revealed that money discounting was associated with enhanced activity in the right dorsolateral prefrontal cortex, involved in executive control; the right dorsal striatum, associated with reward processing; and the left hippocampus, involved in memory encoding/retrieval. Food discounting, instead, was associated with higher activity in the left temporoparietal junction suggesting social reinforcement of food decisions. Although our findings do not confirm our hypothesis of different discounting strategies for different reward types, they are in line with the notion that reward types have a significant influence on impulsivity with primary rewards leading to more impulsive choices.

[Associated factors of intraoperative hemodynamic instability in patients with incidental pheochromocytomas].

Objective: To analyze the associated factors of intraoperative hemodynamic instability (HI) in patients with incidental pheochromocytomas. Methods: The data of 104 patients with a pathological diagnosis of pheochromocytoma at Chinese PLA General Hospital between January 2011 and December 2016 was retrospectively analyzed. The patients were divided into hemodynamic stability (HS) group (n=56) and HI group (n=48) according to hemodynamic characteristics. The clinical features, biochemical test, preoperative and intraoperative hemodynamics were analyzed. Multivariate logistic regression analysis was used to explore the associated factors of HI. Results: The age [(44.7±12.7) years vs (52.1±12.8) years], tumor diameter [(47.9±16.3) mm vs (57.9±21.6) mm], preoperative blood pressure [(121.3±11.5) mmHg vs (127.2±13.3) mmHg] in HS group were less than those in HI group (all P<0.05). The proportion of age ≥ 50 years (28.6% vs 64.6%), tumor diameter ≥ 45 mm (48.2% vs 68.8%) and hematocrit < 0.38 (25.0% vs 51.3%) in HS group were less than that in HI group (all P<0.05). Multivariate logistic regression analysis indicated that age ≥ 50 years (OR=7.940, 95% CI: 2.480-25.417, P<0.001), tumor diameter ≥ 45 mm (OR=5.042, 95% CI: 1.482-17.156, P=0.010), blood pressure ≥ 130/80 mmHg (OR=3.127, 95% CI: 1.034-9.463, P=0.044) and hematocrit < 0.38 (OR=6.273, 95% CI: 1.893-20.788, P=0.003) were independent associated factors of HI. The proportion of HI ( χ(2)=9.033, P=0.003) and intensive care unit (ICU) admission ( χ(2)=16.641, P<0.001) increased along with increasing associated factors. Conclusion: Adequate preoperative medical preparation and volume expansion for appropriate blood pressure are important for elder patients with large tumor to prevent HI in patients with incidental pheochromocytomas.

Movement-related phase locking in the delta-theta frequency band.

Movements result from a complex interplay of multiple brain regions. These regions are assembled into distinct functional networks depending on the specific properties of the action. However, the nature and details of the dynamics of this complex assembly process are unknown. In this study, we sought to identify key markers of the neural processes underlying the preparation and execution of motor actions that always occur irrespective of differences in movement initiation, hence the specific neural processes and functional networks involved. To this end, EEG activity was continuously recorded from 18 right-handed healthy participants while they performed a simple motor task consisting of button presses with the left or right index finger. The movement was performed either in response to a visual cue or at a self-chosen, i.e., non-cued point in time. Despite these substantial differences in movement initiation, dynamic properties of the EEG signals common to both conditions could be identified using time-frequency and phase locking analysis of the EEG data. In both conditions, a significant phase locking effect was observed that started prior to the movement onset in the δ-θ frequency band (2-7Hz), and that was strongest at the electrodes nearest to the contralateral motor region (M1). This phase locking effect did not have a counterpart in the corresponding power spectra (i.e., amplitudes), or in the event-related potentials. Our finding suggests that phase locking in the δ-θ frequency band is a ubiquitous movement-related signal independent of how the actual movement has been initiated. We therefore suggest that phase-locked neural oscillations in the motor cortex are a prerequisite for the preparation and execution of motor actions.

[Timed dose-response relationship analysis of pressor and hypotensive action of drugs].

The graded and timed dose-response relationship (TDRR) of pressor and hypotensive action by i.v. norepinephrine (NE) and sodium nitroprusside (SNP) respectively were studied in 13 male rabbits. The arterial blood pressure was dose-dependently raised by NE 0.98-125 micrograms.kg-1 and lowered by SNP 7.81-500 micrograms.kg-1 (F test, P < 0.01). The comparisons between dose groups showed that the latency and duration of both NE and SNP action were dose-dependent (P < 0.01), and the data were nonlinear least-square fit to the hyperbolic 4-parameter model II (HFPM): Y = cs + 1/(magnitude of ln X - a)s + b, weighting the square error inversely with the square of Sx. In duration data, the regression equation was Y = 462.9906/(6.6924 - ln X) 0.9701 - 24.3335 for NE and Y = 374935.1632/(12.8573 - ln X)3.3975 - 3.139 for SNP action, while in latency, Y = 345.5548/(ln X + 7.8428)2.4056 + 3.9809 and Y = 17.9595/(ln X - 0.4898)0.5763 + 1.4768 for NE and SNP, respectively. Moreover, the positive correlation was found between the peak-reaching time or average rising rate of the drug actions and the dose groups (P < 0.01). The results proved that the hyperbolic type of TDRR existed in the pressor and hypotensive action by iv drugs, and the HFPM was the common mathematical model to fit different TDRR data.

Differences in the membrane skeleton proteins of RBC of AMoL patients.

We report here the different components of erythrocyte membrane skeleton proteins between acute monocytic leukemic (AMoL) patients and normal people. The bands in the 2 region of ghost membrane from AMoL patients exhibited significant differences on SDS gel electrophoresis. Band 2.2 was found to be missing and a "new" band with molecular weight (MW) 161,000 appeared. Also band 4.9 was missing, and the amounts of spectrin, actin, and band 4.8 of AMoL patients were decreased markedly. No such alterations can be seen in normal individuals, even in acute myeloid leukemic (AML) and chronic myeloid leukemic (CML) patients.

Clonal characteristics of fibrous plaques and fatty streaks from human aortas.

Using isoenzymes of glucose-6-phosphate dehydrogenase (G-6-PD) as cellular markers, a study was made of atherosclerotic fibrous plaques and fatty streaks in aortas of black women heterozygous for G-6-PD. Of 29 fibrous plaques, 26 (89.7%) contained only one isoenzyme (17, A; 9, B), the other three containing both A and B. Of 28 fatty streaks, five (17.8%) contained only one isoenzyme (2, A; 3, B), the remaining 23 containing both A and B. Normal uninvolved aorta contained both A and B isoenzymes in 99 of 101 samples. These results confirm the monoclonal character of atherosclerotic fibrous plaques; this strands in contrast to the fatty streaks which most commonly contain the two isoenzymes. The studies on the fatty streaks are inconclusive at this stage in determining whether the streak is the forerunner of the fibrous plaque.