Pattern Filtering for Detection of Neural Activity, with Examples from HVc Activity During Sleep in Zebra Finches

2003 ◽  
Vol 15 (10) ◽  
pp. 2307-2337 ◽  
Author(s):  
Zhiyi Chi ◽  
Peter L. Rauske ◽  
Daniel Margoliash
Keyword(s):  
Neural Coding ◽  
Point Processes ◽  
Statistical Significance ◽  
Test Procedure ◽  
Surrogate Data ◽  
Likelihood Ratios ◽  
Alignment Procedure ◽  
Auditory Evoked Response ◽  
The Individual ◽  
Spiking Activity

The detection of patterned spiking activity is important in the study of neural coding. A pattern filtering approach is developed for pattern detection under the framework of point processes, which offers flexibility in combining temporal details and firing rates. The detection combines multiple steps of filtering in a coarse-to-fine manner. Under some conditional Poisson assumptions on the spiking activity, each filtering step is equivalent to classifying by likelihood ratios all the data segments as targets or as background sequences. Unlike previous studies, where global surrogate data were used to evaluate the statistical significance of the detected patterns, a localizedp-test procedure is developed, which better accounts for firing modulation and nonstationarity in spiking activity. Common temporal structures of patterned activity are learned using an entropy-based alignment procedure, without relying on metrics or pair-wise alignment. Applications of pattern filtering to single, presumptive interneurons recorded in the nucleus HVc of zebra finch are illustrated. These demonstrate a match between the auditory-evoked response to playback of the individual bird's own song and spontaneous activity during sleep. Small temporal compression or expansion, or both, is required for optimal matching of spontaneous patterns to stimulus-evoked activity.

Statistical Method for Detection of Phase-Locking Episodes in Neural Oscillations

2004 ◽  
Vol 91 (4) ◽  
pp. 1883-1898 ◽  
Author(s):  
Jose M. Hurtado ◽  
Leonid L. Rubchinsky ◽  
Karen A. Sigvardt
Keyword(s):  
Phase Locking ◽  
Temporal Structure ◽  
Statistical Significance ◽  
Surrogate Data ◽  
Alternative Methods ◽  
Phase Variable ◽  
Amplitude Fluctuations ◽  
Narrow Frequency Band ◽  
Neural Interactions ◽  
The Individual

In many networks of oscillatory neurons, synaptic interactions can promote the entrainment of units into phase-coupled groups. The detection of synchrony in experimental data, especially if the data consist of single-trial runs, can be problematic when, for example, phase entrainment is of short duration, buried in noise, or masked by amplitude fluctuations that are uncorrelated among the oscillating units. In the present study, we tackle the problem of detecting neural interactions from pairs of oscillatory signals in a narrow frequency band. To avoid the interference of amplitude fluctuations in the detection of synchrony, we extract a phase variable from the data and utilize statistical indices to measure phase locking. We use three different phase-locking indices based on coherence, entropy, and mutual information between the phase variables. Phase-locking indices are calculated over time using sliding analysis windows. By varying the duration of the analysis windows, we were able to inspect the data at different levels of temporal resolution and statistical reliability. The statistical significance of high index values was evaluated using four different surrogate data methods. We determined phase-locking indices using alternative methods for generating surrogate data and found that results are sensitive to the particular method selected. Surrogate methods that preserve the temporal structure of the individual phase time series decrease substantially the number of false positives when tested on a pair of independent signals.

scholarly journals Composite Tests under Corrupted Data

Entropy ◽  
2019 ◽  
Vol 21 (1) ◽  
pp. 63 ◽  
Author(s):  
Michel Broniatowski ◽  
Jana Jurečková ◽  
Ashok Moses ◽  
Emilie Miranda
Keyword(s):  
Likelihood Ratio ◽  
Measurement Errors ◽  
Test Procedure ◽  
Random Variable ◽  
Finite Sample ◽  
Likelihood Ratios ◽  
Test Procedures ◽  
Leibler Divergence ◽  
Definition Of ◽  
The Individual

This paper focuses on test procedures under corrupted data. We assume that the observations Z i are mismeasured, due to the presence of measurement errors. Thus, instead of Z i for i = 1 , … , n, we observe X i = Z i + δ V i, with an unknown parameter δ and an unobservable random variable V i. It is assumed that the random variables Z i are i.i.d., as are the X i and the V i. The test procedure aims at deciding between two simple hyptheses pertaining to the density of the variable Z i, namely f 0 and g 0. In this setting, the density of the V i is supposed to be known. The procedure which we propose aggregates likelihood ratios for a collection of values of δ. A new definition of least-favorable hypotheses for the aggregate family of tests is presented, and a relation with the Kullback-Leibler divergence between the sets f δ δ and g δ δ is presented. Finite-sample lower bounds for the power of these tests are presented, both through analytical inequalities and through simulation under the least-favorable hypotheses. Since no optimality holds for the aggregation of likelihood ratio tests, a similar procedure is proposed, replacing the individual likelihood ratio by some divergence based test statistics. It is shown and discussed that the resulting aggregated test may perform better than the aggregate likelihood ratio procedure.

The Subjective Present and Its Modulation in Clinical Contexts

2013 ◽  
Vol 1 (2) ◽  
pp. 239-259 ◽  
Author(s):  
Wolfgang Tschacher ◽  
Fabian Ramseyer ◽  
Claudia Bergomi
Keyword(s):  
Perceptual Grouping ◽  
Statistical Significance ◽  
Temporal Distribution ◽  
Future Research ◽  
Implicit Processes ◽  
The Social ◽  
Gestalt Perception ◽  
Psychotherapeutic Techniques ◽  
The Mean ◽  
The Individual

Time is a basic dimension in psychology, underlying behavior and experience. Timing and time perception constitute implicit processes that are often inaccessible to the individual person. Research in this field has shown that timing is involved in many areas of clinical significance. In the projects presented here, we combine timing with seemingly different fields of research, such as psychopathology, perceptual grouping, and embodied cognition. Focusing on the time scale of the subjective present, we report findings from three different clinical studies: (1) We studied perceived causality in schizophrenia patients, finding that perceptual grouping (‘binding’, ‘Gestalt formation’), which leads to visual causality perceptions, did not distinguish between patients and healthy controls. Patients however did integrate context (provided by the temporal distribution of auditory context stimuli) less into perceptions, in significant contrast to controls. This is consistent with reports of higher inaccuracy in schizophrenia patients’ temporal processing. (2) In a project on auditory Gestalt perception we investigated auditory perceptual grouping in schizophrenia patients. The mean dwell time was positively related to how much patients were prone to auditory hallucinations. Dwell times of auditory Gestalts may be regarded as operationalizations of the subjective present; findings thus suggested that patients with hallucinations had a shorter present. (3) The movement correlations of interacting individuals were used to study the non-verbal synchrony between therapist and patient in psychotherapy sessions. We operationalized the duration of an embodied ‘social present’ by the statistical significance of such associations, finding a window of roughly 5.7 seconds in conversing dyads. We discuss that temporal scales of nowness may be modifiable, e.g., by mindfulness. This yields promising goals for future research on timing in the clinical context: psychotherapeutic techniques may alter binding processes, hence the subjective present of individuals, and may affect the social present in therapeutic interactions.

Stability in Waking-Sleep States in Neonates as a Predictor of Long-Term Neurologic Outcome

PEDIATRICS ◽  
1985 ◽  
Vol 76 (1) ◽  
pp. 52-63
Author(s):  
Cesare T. Lombroso ◽  
Yoichi Matsumiya
Keyword(s):  
Statistical Significance ◽  
Observation Time ◽  
Long Term Outcomes ◽  
Newborn Period ◽  
Waking And Sleep ◽  
Total Observation Time ◽  
Total Observation ◽  
The Individual

Thirty-three full-term neonates were ranked blindly on a scale ranging from the least to the highest "risk" for future neurologic complications on the basis of available perinatal biographies, tests, and examinations performed during the newborn period. Four prolonged polygraphic-behavioral recordings were obtained one week apart beginning at ten days after birth. Five waking and sleep states were scored in each session as percentages of total observation time, giving a total of 20 scores for each baby to be subjected to analysis of variance. These measures also provided individual profile consistency or variability in maintaining waking-sleep states over the selected period of postnatal time. The whole cohort, except three infants who could not be followed adequately, was then reexamined periodically over a period ranging from 3 to 4 years (±6 months) for neurologic and developmental assessments. Except for two scores that produced a low level of statistical significance (P < .05), the other 18 scores were found to be not associated with long-term outcomes. Even the first two scores were not satisfactory discriminators for the outcome of the individual babies. However, when coefficients of concordance (W) were computed from each individual baby profile, significant statistics (P < .001) emerged to indicate good correlations between high or low W values in the newborn period and long-term outcomes. All 17 newborns who had W scores greater than 0.9 were found to be normal at follow-up regardless of the poor ranking given several of them during the newborn period. Among the 13 newborns who had W scores less than 0.9, 11 had a poor clinical outcome at follow-up, though several had been ranked initially as falling within the least "risk" group.

scholarly journals Synthesis and Characterization of a Bioartificial Polymeric System with Potential Antibacterial Activity: Chitosan-Polyvinyl Alcohol-Ampicillin

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3109 ◽  
Author(s):  
Andres Bernal-Ballen ◽  
Jorge Lopez-Garcia ◽  
Martha-Andrea Merchan-Merchan ◽  
Marian Lehocky
Keyword(s):  
Antibacterial Activity ◽  
Polyvinyl Alcohol ◽  
Statistical Significance ◽  
Antibacterial Properties ◽  
Intermolecular Forces ◽  
Polymeric System ◽  
Bacterial Strains ◽  
Natural Polymers ◽  
The Matrix ◽  
The Individual

Bio-artificial polymeric systems are a new class of polymeric constituents based on blends of synthetic and natural polymers, designed with the purpose of producing new materials that exhibit enhanced properties with respect to the individual components. In this frame, a combination of polyvinyl alcohol (PVA) and chitosan, blended with a widely used antibiotic, sodium ampicillin, has been developed showing a moderate behavior in terms of antibacterial properties. Thus, aqueous solutions of PVA at 1 wt.% were mixed with acid solutions of chitosan at 1 wt.%, followed by adding ampicillin ranging from 0.3 to 1.0 wt.% related to the total amount of the polymers. The prepared bio-artificial polymeric system was characterized by FTIR, SEM, DSC, contact angle measurements, antibacterial activity against Staphylococcus aureus and Escherichia coli and antibiotic release studies. The statistical significance of the antibacterial activity was determined using a multifactorial analysis of variance with ρ < 0.05 (ANOVA). The characterization techniques did not show alterations in the ampicillin structure and the interactions with polymers were limited to intermolecular forces. Therefore, the antibiotic was efficiently released from the matrix and its antibacterial activity was preserved. The system disclosed moderate antibacterial activity against bacterial strains without adding a high antibiotic concentration. The findings of this study suggest that the system may be effective against healthcare-associated infections, a promising view in the design of novel antimicrobial biomaterials potentially suitable for tissue engineering applications.

scholarly journals A cross-sectional study of the use and effectiveness of the Individual Development Plan among doctoral students

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 722 ◽  
Author(s):  
Nathan L. Vanderford ◽  
Teresa M. Evans ◽  
L. Todd Weiss ◽  
Lindsay Bira ◽  
Jazmin Beltran-Gastelum
Keyword(s):  
Career Development ◽  
Doctoral Students ◽  
Online Survey ◽  
Career Planning ◽  
Statistical Significance ◽  
Development Plan ◽  
Individual Development ◽  
Negative Consequences ◽  
Cross Sectional ◽  
The Individual

Background: The Individual Development Plan (IDP) was introduced as a tool to aid in career planning for doctoral trainees. Despite the National Institutes of Health and academic institutions creating policies that mandate the use of IDPs, little information exists regarding the use and effectiveness of the career planning tool. Methods: We conducted a multi-institutional, online survey to measure IDP use and effectiveness. The survey was distributed to potential respondents via social media and direct email. IDP survey questions were formatted using a five-point Likert scale (strongly agree, agree, neutral, disagree and strongly disagree). For data analysis purposes, responses were grouped into two categories (agree versus does not agree/disagree). The data were summarized as one-way frequencies and the Pearson chi-square test was used to determine the statistical significance of univariate associations between the survey variables and an outcome measure of the effectiveness of the IDP. Results: Among all respondents, fifty-three percent reported that they are required to complete an IDP while thirty-three percent reported that the tool is helpful to their career development. Further, our data suggests that the IDP is most effective when doctoral students complete the tool with faculty mentors with whom they have a positive relationship. Respondents who are confident about their career plans and who take advantage of career development resources at their institution are also more likely to perceive that the IDP is useful for their career development. Conclusion: Given the nuanced use and effectiveness of the IDP, we call for additional research to characterize the overall use and effectiveness of the IDP and to determine whether there are unintended negative consequences created through the use of the tool. Furthermore, we recommend an enhancement of career development infrastructure that would include mentorship training for faculty in order to provide substantially more career planning support to trainees.

scholarly journals Associations between Modifiable Health-Risk Behaviors and Personality Types

2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Jon C. Schommer ◽  
Paul D. Tieger ◽  
Anthony W. Olson ◽  
Lawrence M. Brown
Keyword(s):  
Health Risk ◽  
Risk Behaviors ◽  
Statistical Significance ◽  
Personality Type ◽  
Health Risk Behaviors ◽  
Personality Types ◽  
Chi Square ◽  
Related Stress ◽  
The Individual ◽  
Chi Square Analysis

Objectives: The first objective for this study was to explore if characteristics of personality type (using the Preferred Communication Style Questionnaire) are associated with the following modifiable health-risk behaviors: smoking, exercise, alcohol consumption, nutrition, sleep, depression-related stress, anxiety-related stress, healthcare professional usage, and self-discipline. The second objective for this study was to explore if characteristics of personality type are associated with (1) the quality of patient-physician relationships, (2) patient-physician communication, and (3) preferred method for receiving information. Methods: Data were collected from 10,500 adult individuals residing in the United States via an on-line, self-administered survey coordinated by Qualtrics Panels from March 14-30, 2016. Chi-square analysis was used for making comparisons between categories of personality types and items related to health-risk behaviors. Statistical significance was set at p < 0.05. However, chi-square analysis with large sample sizes (e.g. 10,500 in this study) readily yields statistical significance. Practical significance was set at four or more percentage points above or below the overall mean. Results: Regarding objective 1, personality type was associated with all nine health-risk behaviors studied. Personality types within the Experiencer temperament (17% of the U.S. population) accounted for 46% of the undesirable scores we computed for health-risk behaviors. The Idealist temperament (17% of population) accounted for 32% of the undesirable scores. Conceptualizers (10% of population) accounted for 17% of the undesirable scores and Traditionalists (46% of population) accounted for 5% of the undesirable scores. Regarding objective 2, the findings showed that personality type was associated with (1) the importance people place on the patient-physician relationship, (2) which characteristics of that relationship are most desirable, (3) desire for more communication with their physician, and (4) the preferred method for receiving information. Discussion and Conclusions: Precision medicine has been proposed as a way to create a new taxonomy of disease that uses individual specific data to develop accurate diagnosis, targeted treatment, and improved health outcomes. Based on the findings of this study, we propose that inclusion of personality type is an important component of these efforts so that the health care system can conform more to the individual patient in order to increase engagement and adherence, reduce errors, minimize ineffective treatment and waste, and can be cost effective. Conflict of Interest Co-author, Paul Tieger is CEO of SpeedReading People, LLC which holds copyright for the Individual Wellness Plan and Adherence Predictive Index tools that are mentioned in this manuscript.   Type: Original Research

Idiom variation and decomposability Part II: Variation in the noun phrase

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Attila Cserép
Keyword(s):  
Noun Phrase ◽  
American English ◽  
Statistical Significance ◽  
Dependence Relation ◽  
Number Variation ◽  
The Individual

AbstractVariant forms of idioms have been extracted from an American English corpus of 450 million words to test the idiom decomposition hypothesis, which proposes a dependence relation between the degree of idiom decomposability and the extent to which expressions are variable. The more decomposable the idiom is, the more flexibility it is expected to exhibit. In this second part of the study, morphological flexibility (number and determiner) as well as lexico- syntactic flexibility (the addition of various pre- and postmodifiers) of the noun have been assessed and related to three decomposability rankings. The results provide some support for the hypothesis. Of the individual flexibility dimensions, only number variation has been found to be significantly dependent on scalar decomposability. Of the overall measures, noun morphology and overall noun variation are significantly correlated. The relation between overall modifier variation and scalar decomposability is close to statistical significance, although premodifier and postmodifier variations taken separately do not show any dependence. None of the variation measures appear to be related to categorical decomposability.

The null-hypothesis significance-test procedure is still warranted

1998 ◽  
Vol 21 (2) ◽  
pp. 228-235 ◽  
Author(s):  
Siu L. Chow
Keyword(s):  
Null Hypothesis ◽  
Statistical Power ◽  
Meta Analysis ◽  
Statistical Significance ◽  
Test Procedure ◽  
Significance Test ◽  
Null Hypothesis Significance Test ◽  
Wide Range ◽  
Statistical Hypotheses ◽  
Alternative Hypotheses

Entertaining diverse assumptions about empirical research, commentators give a wide range of verdicts on the NHSTP defence in Statistical significance. The null-hypothesis significance-test procedure (NHSTP) is defended in a framework in which deductive and inductive rules are deployed in theory corroboration in the spirit of Popper's Conjectures and refutations (1968b). The defensible hypothetico-deductive structure of the framework is used to make explicit the distinctions between (1) substantive and statistical hypotheses, (2) statistical alternative and conceptual alternative hypotheses, and (3) making statistical decisions and drawing theoretical conclusions. These distinctions make it easier to show that (1) H0 can be true, (2) the effect size is irrelevant to theory corroboration, and (3) “strong” hypotheses make no difference to NHSTP. Reservations about statistical power, meta-analysis, and the Bayesian approach are still warranted.

scholarly journals MIENTURNET: an interactive web tool for microRNA-target enrichment and network-based analysis

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Valerio Licursi ◽  
Federica Conte ◽  
Giulia Fiscon ◽  
Paola Paci
Keyword(s):  
Web Application ◽  
Mirna Target ◽  
Statistical Significance ◽  
Holistic Approach ◽  
Emergent Properties ◽  
Mirna Regulation ◽  
Microrna Target ◽  
Web Tool ◽  
The Individual ◽  
Downstream Analysis

Abstract Background miRNAs regulate the expression of several genes with one miRNA able to target multiple genes and with one gene able to be simultaneously targeted by more than one miRNA. Therefore, it has become indispensable to shorten the long list of miRNA-target interactions to put in the spotlight in order to gain insight into understanding the regulatory mechanism orchestrated by miRNAs in various cellular processes. A reasonable solution is certainly to prioritize miRNA-target interactions to maximize the effectiveness of the downstream analysis. Results We propose a new and easy-to-use web tool MIENTURNET (MicroRNA ENrichment TURned NETwork) that receives in input a list of miRNAs or mRNAs and tackles the problem of prioritizing miRNA-target interactions by performing a statistical analysis followed by a fully featured network-based visualization and analysis. The statistics is used to assess the significance of an over-representation of miRNA-target interactions and then MIENTURNET filters based on the statistical significance associated with each miRNA-target interaction. In addition, the holistic approach of the network theory is used to infer possible evidences of miRNA regulation by capturing emergent properties of the miRNA-target regulatory network that would be not evident through a pairwise analysis of the individual components. Conclusion MIENTURNET offers the possibility to consistently perform both statistical and network-based analyses by using only a single tool leading to a more effective prioritization of the miRNA-target interactions. This has the potential to avoid researchers without computational and informatics skills to navigate multiple websites and thus to independently investigate miRNA activity in every cellular process of interest in an easy and at the same time exhaustive way thanks to the intuitive web interface. The web application along with a well-documented and comprehensive user guide are freely available at http://userver.bio.uniroma1.it/apps/mienturnet/ without any login requirement.

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