Impact of Number of Likert Alternatives: The Role of Response Variability on Composite Score Psychometrics

2011 ◽  
Author(s):  
Frances L. Chumney ◽  
James A. Bovaird
Keyword(s):  
Response Variability ◽  
Composite Score

scholarly journals Genetic disruption of the On visual pathway affects cortical orientation selectivity and contrast sensitivity in mice

2014 ◽  
Vol 111 (11) ◽  
pp. 2276-2286 ◽  
Author(s):  
Rashmi Sarnaik ◽  
Hui Chen ◽  
Xiaorong Liu ◽  
Jianhua Cang
Keyword(s):  
Contrast Sensitivity ◽  
Visual Pathway ◽  
Response Variability ◽  
Stimulus Contrast ◽  
Wild Type ◽  
Low Contrast ◽  
Pharmacological Blockade ◽  
Single Unit Recordings ◽  
On And Off Pathways

The retina signals stimulus contrast via parallel On and Off pathways and sends the information to higher visual centers. Here we study the role of the On pathway using mice that have null mutations in the On-specific GRM6 receptor in the retina (Pinto LH, Vitaterna MH, Shimomura K, Siepka SM, Balannik V, McDearmon EL, Omura C, Lumayag S, Invergo BM, Brandon M, Glawe B, Cantrell DR, Donald R, Inayat S, Olvera MA, Vessey KA, Kirstan A, McCall MA, Maddox D, Morgans CW, Young B, Pletcher MT, Mullins RF, Troy JB, Takahashi JS. Vis Neurosci 24: 111–123, 2007; Maddox DM, Vessey KA, Yarbrough GL, Invergo BM, Cantrell DR, Inayat S, Balannik V, Hicks WL, Hawes NL, Byers S, Smith RS, Hurd R, Howell D, Gregg RG, Chang B, Naggert JK, Troy JB, Pinto LH, Nishina PM, McCall MA. J Physiol 586: 4409–4424, 2008). In these “nob” mice, single unit recordings in the primary visual cortex (V1) reveal degraded selectivity for orientations due to an increased response at nonpreferred orientations. Contrast sensitivity in the nob mice is reduced with severe deficits at low contrast, consistent with the phenotype of night blindness in human patients with mutations in Grm6. These cortical deficits can be largely explained by reduced input drive and increased response variability seen in nob V1. Interestingly, increased variability is also observed in the superior colliculus of these mice but does not affect its tuning properties. Further, the increased response variability in the nob mice is traced to the retina, a result phenocopied by acute pharmacological blockade of the On pathway in wild-type retina. Together, our results suggest that the On and Off pathways normally interact to increase response reliability in the retina, which in turn propagates to various central visual targets and affects their functional properties.

scholarly journals Neuronal response variability as a product of divisive normalization; neurobiological implications at a macroscale level

2020 ◽  
Vol 3 ◽  
pp. 34
Author(s):  
Kathy L. Ruddy ◽  
David M. Cole ◽  
Colin Simon ◽  
Marc T. Bächinger
Keyword(s):  
Potential Role ◽  
Neuronal Response ◽  
Quantitative Model ◽  
Response Variability ◽  
Sensory Cortex ◽  
Neural Oscillations ◽  
Neural Encoding ◽  
Approach Response ◽  
Divisive Normalization

The occurrence of neuronal spikes recorded directly from sensory cortex is highly irregular within and between presentations of an invariant stimulus. The traditional solution has been to average responses across many trials. However, with this approach, response variability is downplayed as noise, so it is assumed that statistically controlling it will reveal the brain’s true response to a stimulus. A mounting body of evidence suggests that this approach is inadequate. For example, experiments show that response variability itself varies as a function of stimulus dimensions like contrast and state dimensions like attention. In other words, response variability has structure, is therefore potentially informative and should be incorporated into models which try to explain neural encoding. In this article we provide commentary on a recently published study by Coen-Cagli and Solomon that incorporates spike variability in a quantitative model, by explaining it as a function of divisive normalization. We consider the potential role of neural oscillations in this process as a potential bridge between the current microscale findings and response variability at the mesoscale/macroscale level.

scholarly journals Response variability and population coupling of cortical synaptic inputs are strongly influenced by network properties

2016 ◽  
Author(s):  
Nathaniel C. Wright ◽  
Mahmood Hoseini ◽  
Tansel Baran Yasar ◽  
Ralf Wessel
Keyword(s):  
Sensory Processing ◽  
Visual Stimulation ◽  
Ex Vivo ◽  
Fundamental Property ◽  
Small World ◽  
Response Variability ◽  
Network Properties ◽  
Coupling Dynamic ◽  
Evoked Activity

The highly variable spiking of a cortical neuron is “coupled” to that of other neurons in the network. This has implications for sensory coding, and appears to represent a fundamental property of cortical sensory processing. To date, most studies of population coupling have focused on recorded spiking activity, an approach that suffers from several confounding issues. Moreover, the contributions of various network properties to population coupling are largely unexplored. To this end, we recorded the membrane potential (V) and the nearby LFP in the visual cortex of the turtle ex vivo wholebrain preparation during ongoing and visually-evoked activity. We used an algorithm to infer the excitatory conductance (g) from V, and calculated the g-LFP coupling. We found that g-LFP coupling was highly variable across neurons, and increased following visual stimulation before relaxing to intermediate values. To investigate the role of the network, we implemented a driven small-world network of leaky integrate-and-fire neurons. This model reproduces the large across-trial response variability and g-LFP coupling dynamic, and suggests crucial roles for anatomical and emergent network properties.

The Role of Adherence in the Effects of a Mindfulness Intervention for Competitive Athletes: Changes in Mindfulness, Flow, Pessimism, and Anxiety

2016 ◽  
Vol 10 (2) ◽  
pp. 99-117 ◽  
Author(s):  
John Scott-Hamilton ◽  
Nicola S. Schutte
Keyword(s):  
Mindfulness Training ◽  
Composite Score ◽  
Mindfulness Practice ◽  
Somatic Anxiety ◽  
Mindfulness Intervention ◽  
Movement Training ◽  
Competitive Athletes ◽  
High Adherence

This study examined the role of degree of adherence in a mindfulness-based intervention on mindfulness, flow, sport anxiety, and sport-related pessimistic attributions in athletes. Twelve athletes participated in an 8-week mindfulness intervention which incorporated a mindfulness focus on movement training component. Participants completed baseline and posttest measures of mindfulness, flow, sport anxiety, and sport-related pessimistic attributions, and they filled out daily mindfulness-training logbooks documenting their frequency and duration of mindfulness practice. Participants were identified as either high adherence or low adherence with mindfulness-training based on a composite score of logbook practice records and workshop attendance. Athletes high in adherence, operationalized as following recommended practice of mindfulness exercises, showed significantly greater increases in mindfulness and aspects of flow, and significantly greater decreases in pessimism and anxiety than low adherence athletes. Greater increases in mindfulness from baseline to posttest were associated with greater increases in flow and greater decreases in pessimism. Increases in flow were associated with decreases in somatic anxiety and pessimism.

scholarly journals Author response: Variability in locomotor dynamics reveals the critical role of feedback in task control

2019 ◽  
Author(s):  
Ismail Uyanik ◽  
Shahin Sefati ◽  
Sarah A Stamper ◽  
Kyoung-A Cho ◽  
M Mert Ankarali ◽  
...  
Keyword(s):  
Critical Role ◽  
Response Variability ◽  
Author Response ◽  
Task Control

scholarly journals On the Relation Between Variability and Creativity: A Summary of Early Work and Advancements from Applied Research

2019 ◽  
Vol 21 (3) ◽  
pp. 289-302
Author(s):  
Joseph Dracobly
Keyword(s):  
Environmental Variables ◽  
Applied Research ◽  
Environmental Influence ◽  
Response Variability ◽  
Response Class ◽  
Lag Schedule ◽  
Behavior Analysts ◽  
Lag Schedules ◽  
Conceptual Work

Creativity, or the generation of previously unobserved behavior, is a topic of interest to scientists and the general public alike. Researchers outside behavior analysis have focused on creativity as a trait of individuals. Behavior analysts, however, have focused on the variables that give rise to novel responses. Initial conceptual work examined specific environmental variables that may promote creativity. Subsequent conceptual work examined the role of the response class and the selective nature of reinforcement. As this conceptual work progressed, researchers began evaluating variables that affect response variability, a potentially critical component of variability. Most basic researchers, and some applied researchers, have focused on response sequences. Although this work has proven fruitful in understanding response variability as an operant dimension, these limited response classes have prevented a more robust understanding of variability and novelty. Following the development of the lag schedule, applied researchers began using lag schedules to increase complex behavior behavior such as responses to questions, social skills, and martial arts skills. This applied work has provided intriguing evidence that variability, and environmental influence of variability, is a key contributor to novel responding, thus bringing creativity well into our scientific understanding of behavior.

Antiplatelet drug response variability and the role of platelet function testing: A practical guide for interventional cardiologists

2009 ◽  
Vol 73 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Dominick J. Angiolillo ◽  
Siva Suryadevara ◽  
Piera Capranzano ◽  
Martin Z. Zenni ◽  
Luis A. Guzman ◽  
...  
Keyword(s):  
Platelet Function ◽  
Drug Response ◽  
Response Variability ◽  
Antiplatelet Drug ◽  
Platelet Function Testing ◽  
Practical Guide ◽  
Function Testing

Central angiotensin II receptors mediate hemodynamic response variability to stressors

2006 ◽  
Vol 291 (3) ◽  
pp. R719-R727 ◽  
Author(s):  
Kayla D. Rowe ◽  
Julie A. Schwartz ◽  
Lance L. Lomax ◽  
Mark M. Knuepfer
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cardiac Output ◽  
Cold Water ◽  
Pressor Response ◽  
Response Variability ◽  
Angiotensin Ii Receptors ◽  
Ang Ii ◽  
The Central Nervous System

We examined whether ANG II receptors in the central nervous system mediate hemodynamic responses to pharmacological (cocaine) and behavioral (cold water) stressors. After administration of cocaine (5 mg/kg iv), rats were classified as vascular responders (VR) if their pressor response was due entirely to an increase in systemic vascular resistance (SVR) despite a decrease in cardiac output (CO). Cocaine elicited a pressor response in mixed responders (MR) that was dependent on small increases in both SVR and CO. ANG II (30 ng/5 μl icv, 5 min before cocaine) augmented the decrease in CO in VR and prevented the increase in CO in MR. Administration of [Sar1,Thr8]ANG II (20 μg/5 μl icv; sarthran) before cocaine attenuated the decrease in CO and the large increase in SVR in VR so that they were no longer different from MR. Losartan (20 μg icv) or captopril (50 μg icv) preceding cocaine administration also attenuated the decrease in CO and the large increase in SVR seen in VR only. The role of angiotensin was not specific for cocaine, because ANG II (icv) pretreatment before startle with cold water (1 cm deep) enhanced the decrease in CO and the increase in SVR in both MR and VR, whereas losartan (icv) pretreatment before startle attenuated the decrease in CO and the increase in SVR in VR so that they were no longer different from MR. These data suggest that central ANG II receptors mediate the greater vascular and cardiac responsiveness in vascular responders to acute pharmacological and behavioral stressors.

scholarly journals A Bidirectional Mendelian Randomization Study to evaluate the causal role of reduced blood vitamin D levels with type 2 diabetes risk in South Asians and Europeans

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Cynthia A. Bejar ◽  
Shiwali Goyal ◽  
Shoaib Afzal ◽  
Massimo Mangino ◽  
Ang Zhou ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Vitamin D ◽  
Mendelian Randomization ◽  
Composite Score ◽  
Causal Role ◽  
Z Score ◽  
Increased Risk ◽  
Vitamin D Levels

Abstract Context Multiple observational studies have reported an inverse relationship between 25-hydroxyvitamin D concentrations (25(OH)D) and type 2 diabetes (T2D). However, the results of short- and long-term interventional trials concerning the relationship between 25(OH)D and T2D risk have been inconsistent. Objectives and methods To evaluate the causal role of reduced blood 25(OH)D in T2D, here we have performed a bidirectional Mendelian randomization study using 59,890 individuals (5,862 T2D cases and 54,028 controls) from European and Asian Indian ancestries. We used six known SNPs, including three T2D SNPs and three vitamin D pathway SNPs, as a genetic instrument to evaluate the causality and direction of the association between T2D and circulating 25(OH)D concentration. Results Results of the combined meta-analysis of eight participating studies showed that a composite score of three T2D SNPs would significantly increase T2D risk by an odds ratio (OR) of 1.24, p = 1.82 × 10–32; Z score 11.86, which, however, had no significant association with 25(OH)D status (Beta -0.02nmol/L ± SE 0.01nmol/L; p = 0.83; Z score -0.21). Likewise, the genetically instrumented composite score of 25(OH)D lowering alleles significantly decreased 25(OH)D concentrations (-2.1nmol/L ± SE 0.1nmol/L, p = 7.92 × 10–78; Z score -18.68) but was not associated with increased risk for T2D (OR 1.00, p = 0.12; Z score 1.54). However, using 25(OH)D synthesis SNP (DHCR7; rs12785878) as an individual genetic instrument, a per allele reduction of 25(OH)D concentration (-4.2nmol/L ± SE 0.3nmol/L) was predicted to increase T2D risk by 5%, p = 0.004; Z score 2.84. This effect, however, was not seen in other 25(OH)D SNPs (GC rs2282679, CYP2R1 rs12794714) when used as an individual instrument. Conclusion Our new data on this bidirectional Mendelian randomization study suggests that genetically instrumented T2D risk does not cause changes in 25(OH)D levels. However, genetically regulated 25(OH)D deficiency due to vitamin D synthesis gene (DHCR7) may influence the risk of T2D.

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