Estimation of time-dependent input from neuronal membrane potential

The set of firing rates of the presynaptic excitatory and inhibitory neurons constitutes the input signal to the postsynaptic neuron. Estimation of the time-varying input rates from intracellularly recorded membrane potential is investigated here. For that purpose, the membrane potential dynamics must be specified. We consider the Ornstein-Uhlenbeck stochastic process, one of the most common single-neuron models, with time-dependent mean and variance. Assuming the slow variation of these two moments, it is possible to formulate the estimation problem by using a state-space model. We develop an algorithm that estimates the paths of the mean and variance of the input current by using the empirical Bayes approach. Then the input firing rates are directly available from the moments. The proposed method is applied to three simulated data examples: constant signal, sinusoidally modulated signal, and constant signal with a jump. For the constant signal, the estimation performance of the method is comparable to that of the traditionally applied maximum likelihood method. Further, the proposed method accurately estimates both continuous and discontinuous time-variable signals. In the case of the signal with a jump, which does not satisfy the assumption of slow variability, the robustness of the method is verified. It can be concluded that the method provides reliable estimates of the total input firing rates, which are not experimentally measurable.     

Paradoxic decreases in atherosclerotic plaque mass in insulin-treated diabetic patients

This study assessed the impact of diabetes mellitus on atherosclerotic lesion formation. Seventy insulin-treated diabetics, 150 non-insulin-treated diabetics, and 607 nondiabetics with chronic anginal syndromes and de novo native coronary stenoses were studied using (1) angiography, and (2) intravascular ultrasound (reference and lesion arterial, lumen, and plaque areas; area stenosis [reference-lesion/reference lumen area]; remodeling index [reference-lesion lumen area/lesion-reference plaque area]; and slope of the regression line relating lumen area to plaque burden [plaque/arterial area]). Despite being diabetic for longer and having similar lumen compromise, insulin-treated patients had (1) less reference plaque (8.3 +/- 3.4 vs 10.5 +/- 4.5 mm2, p = 0.0015), (2) less stenosis plaque (13.0 +/- 4.9 vs 16.9 mm2, p <0.0001), (3) smaller reference arterial areas (17.1 +/- 5.4 vs 19.7 +/- 6.2 mm2, p = 0.0063), and (4) smaller stenosis arterial areas (15.3 +/- 4.9 vs 19.5 +/- 6.5 mm2, p <0.0001) than non-insulin-treated diabetics. With use of multivariate linear regression analysis, insulin use was an independent (and negative) predictor of reference plaque and arterial areas (p = 0.0308 and p = 0.0179) and stenosis plaque and arterial areas (p = 0.0117 and p = 0.0066). This was also true when normalized for body surface area. The remodeling index showed that insulin treatment resulted in an exaggerated impact of plaque accumulation on lumen compromise. This was confirmed by the slope of the regression line relating lumen area to plaque burden. Patients with a longer duration of diabetes who were treated with insulin for > or = 1 year had (paradoxically) less reference segment and stenosis plaque accumulation. Possible explanations include impaired adaptive remodeling and/or arterial (and plaque) shrinkage.     

Alcohol, expectations, and sexual arousal in males: an information processing analysis

Using a balanced placebo drink administration procedure, 48 undergraduate male social drinkers were presented with erotic and nonerotic stimuli after completing the Mosher Forced-Choice Guilt Scale. Selective attention and recognition memory were measured in both visual and auditory modalities; penile tumescence was recorded continuously in reponse to auditory stimuli. The belief that alcohol had been consumed increased penile tumescence to both heterosexual and homosexual stimuli, but only in Ss high in sex guilt. Mild intoxication itself had no effect. Alcohol impaired memory for visual stimuli, while the belief that alcohol had been drunk facilitated memory for stimuli in the auditory modality. Correlational analysis did not support the hypothesis that alcohol expectation's impact on sexual responsiveness is mediated directly through its influence on selective attention and memory processes. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

School-based intervention for adolescent obesity: Analysis of treatment, randomly selected control, and self-selected control subjects.

55 junior high school students were assigned from stratified blocks of percentage overweight to a comprehensive behavioral program or to a no-treatment condition. The average S in treatment declined in percentage overweight 5.71%; controls gained 2.41%. Parental participation was correlated with weight change among Ss in the treatment group. Comparison of controls with a group of children who refused treatment revealed similar patterns of weight change, suggesting that self-selected controls may be appropriate in this kind of research. (5 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Blood alcohol level discrimination by alcoholics: The role of internal and external cues.

Two groups of 4 chronic alcoholics lived in Rutgers' Alcohol Behavior Research Laboratory for separate 2-wk periods. During that time, Ss were taught to attend either to internal or to external cues to blood alcohol level (BAL). Mean age of the internal group was 36.2 yrs, and that of the external was 35.7 yrs. Internal Ss completed the Body Sensation Checklist and the Mood Adjective Check List. During a single training session, Ss received feedback on actual BAL following each of their BAL estimates. During pretraining and posttraining sessions, assessments of BAL estimation accuracy were obtained in the absence of feedback. Prior to training, both groups were equally inaccurate in estimating BAL. During training, when accurate BAL feedback was provided, estimation accuracy increased significantly for both groups. Once feedback of actual BAL was removed during the posttraining test session, however, only externally trained Ss maintained the ability to estimate BAL accurately. It is concluded that unlike the nonalcoholic Ss studied by H. Huber, R. Karlin, and A. E. Nathan (1976), the alcoholic Ss of the present study did not learn to discriminate BAL on the basis of internal feelings and sensations nearly as adequately as they did when they referred to external cues. It is suggested that these findings may have important implications for the clinical application of BAL discrimination training. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Procedural results and late clinical outcomes after placement of three or more stents in single coronary lesions

BACKGROUND: Previous reports have suggested higher procedural and long-term complications among patients treated with multiple stents for diffuse lesions and/or long dissections. METHODS AND RESULTS: To evaluate procedural success, major complications, and clinical outcomes (> or = 1 year) in a consecutive series of patients treated with multiple (> or = 3) contiguous stents in single lesions, we evaluated in-hospital and long-term (1-year) clinical outcomes in 117 consecutive patients treated with > or = 3 coronary stents compared with a concurrent series of patients treated with 1 or 2 stents (n=1673) between January 1, 1994, and December 31, 1995. Multiple stents were implanted more often in larger vessels, in the right coronary artery or saphenous vein grafts, and for unfavorable lesion characteristics, including long (>20 mm), calcified, ulcerated, thrombotic, and/or flow-obstructing lesions. Overall procedural success was obtained in 97.4% of patients and was similar whether 1 or 2 versus > or = 3 stents were used. Non-Q-wave MI (CK-MB > or = 5 times normal) was more frequent after > or = 3 stents (22.8% versus 13.4%, P=.005). Target lesion revascularization (TLR) was 14.6% for 1 or 2 stents and 13.3% for > or = 3 stents (P=.70). There was no difference in death (2.2% versus 0.9%, P=.34) or Q-wave MI (1.4% versus 0.9%, P=.64) between the two groups (1 or 2 stents versus > or = 3 stents, respectively), and overall cardiac event-free survival was similar during follow-up (P=.70). CONCLUSIONS: Patients treated with multiple (> or = 3) contiguous stents compared with 1 or 2 stents have (1) similar in-hospital procedural success and major complications despite having more unfavorable lesion characteristics, (2) a higher rate of procedural non-Q-wave MI, and (3) similar TLR and overall major cardiac event rates during 1 year of follow-up.     

Localized event-based reasoning for multiagent domain1

This paper presents the GEM concurrency model and GEMPLAN, a multiagent planner based on this model. Unlike standard state-based AI representations, GEM is unique in its explicit emphasis on events and domain structure. In particular, a world domain is modeled as a set of regions composed of interrelated events. Event-based temporal-logic constraints are then associated with each region to delimit legal domain behavior. The GEMPLAN planner directly reflects this emphasis on domain structure and constraints. It can be viewed as a general-purpose constraint satisfaction facility which constructs a network of interrelated events (a “plan”) that is subdivided into regions (“subplans”), satisfies all applicable regional constraints, and also achieves some stated goal. GEMPLAN extends and generalizes previous planning architectures in the range of constraint forms it handles and in the flexibility of its constraint satisfaction search strategy. One critical aspect of our work has been an emphasis on localized reasoning—techniques that make explicit use of domain structure. For example, GEM localizes the applicability of domain constraints and imposes additional “locality constraints” on the basis of domain structure. Together, constraint localization and locality constraints provide semantic information that can be used to alleviate several aspects of the frame problem for multiagent domains. The GEMPLAN planner reflects the use of locality by subdividing its constraint satisfaction search space into regional planning search spaces. Utilizing constraint and property localization, GEMPLAN can pinpoint and rectify interactions among these regional search spaces, thus reducing the burden of “interaction analysis” ubiquitous to most planning systems. Because GEMPLAN is specifically geared towards parallel, multiagent domains, we believe that its natural application areas will include scheduling and other forms of organizational coordination.     

The widening scope of shame.

Review of book: Melvin R. Lansky and Andrew T. Morrison (Eds.) The Widening Scope of Shame. Hillsdale, NJ: The Analytic Press, 1997, xviii = 437 pp. Reviewed by Karen J. Maroda. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comment: Word Coding System.

Letter comments that Broadhurst (see record 1963-00108-001), in the article "Coordinate Indexing: A bibliographic Aid" in the American Psychologist, described his "Uniterm" system, a numerical code method, for handling references. The authors go on to explain that they have devised a system for storing and retrieval of social science references which differs from Broadhurst's in using edge-punched cards with a word coding system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Remodeling after directional coronary atherectomy (with and without adjunct percutaneous transluminal coronary angioplasty): a serial angiographic and intravascular ultrasound analysis from the Optimal Atherectomy Restenosis Study

Expression of DNA topoisomerase IIalpha protein varies through the cell cycle with its peak in G2/M. This cell-cycle-dependent expression depends on changes in topoisomerase IIalpha mRNA stability as well as promoter activity. We isolated the 3' genomic region of the mouse topoisomerase IIalpha gene and investigated whether or not the 3' untranslated region (UTR) of the topoisomerase IIalpha mRNA participates in the cell-cycle-dependent mRNA stability. Interestingly, genomic- and RT-PCR analyses revealed that the topoisomerase IIalpha 3' UTR is formed via splicing in mouse, but not in human and hamster. Comparison of the mouse 3' region with the human and hamster regions suggests that this mouse-specific splicing has resulted from an accidental acquisition of the consensus 5' splice site. The minority of the non-spliced topoisomerase IIalpha 3' UTR in mouse was confirmed by Northern blot analysis. We performed transient expression assays using luciferase constructs with the mouse topoisomerase IIalpha 3' genomic region, or the major spliced form of the 3' UTR. However, neither construct affected the cell-cycle-dependent expression of the reporter gene driven by the topoisomerase IIalpha promoter. Our results strongly suggest that the mouse topoisomerase IIalpha 3' UTR by itself is not involved in the cell-cycle-dependent mRNA stability.