WorldWideScience

Sample records for previously learned associations

  1. Stimuli previously associated with reinforcement mitigate resurgence.

    Science.gov (United States)

    Craig, Andrew R; Browning, Kaitlyn O; Shahan, Timothy A

    2017-09-01

    Resurgence refers to the recurrence of an extinguished target behavior following subsequent suspension of alternative reinforcement. Delivery of reinforcers during extinction of alternative behavior has been shown to mitigate resurgence. The present experiment aimed to determine whether delivering stimuli associated with reinforcers during resurgence testing similarly mitigates resurgence. Three groups of rats pressed target levers for food according to variable-interval 15-s schedules during Phase 1. In Phase 2, lever pressing was extinguished, and an alternative nose-poke response produced alternative reinforcement according to a variable-interval 15-s schedule. Food reinforcement was always associated with illumination of the food aperture and an audible click from the pellet dispenser during Phases 1 and 2. Phase 3 treatments differed between groups. For one group, nose poking continued to produce food and food-correlated stimuli. Both of these consequences were suspended for a second group. Finally, nose poking produced food-correlated stimuli but not food for a third group. Target-lever pressing resurged in the group that received no consequences and in the group that received only food-correlated stimuli for nose poking. Resurgence, however, was smaller for the group that received food-correlated stimuli than for the group that received no consequences for nose poking. Target-lever pressing did not increase between phases in the group that continued to receive food and associated stimuli. Thus, delivery of stimuli associated with food reinforcement after suspension of food reduced but did not eliminate resurgence of extinguished lever pressing. These findings contribute to potential methodologies for preventing relapse of extinguished problem behavior in clinical settings. © 2017 Society for the Experimental Analysis of Behavior.

  2. Secondary recurrent miscarriage is associated with previous male birth.

    LENUS (Irish Health Repository)

    Ooi, Poh Veh

    2011-01-01

    Secondary recurrent miscarriage (RM) is defined as three or more consecutive pregnancy losses after delivery of a viable infant. Previous reports suggest that a firstborn male child is associated with less favourable subsequent reproductive potential, possibly due to maternal immunisation against male-specific minor histocompatibility antigens. In a retrospective cohort study of 85 cases of secondary RM we aimed to determine if secondary RM was associated with (i) gender of previous child, maternal age, or duration of miscarriage history, and (ii) increased risk of pregnancy complications. Fifty-three women (62.0%; 53\\/85) gave birth to a male child prior to RM compared to 32 (38.0%; 32\\/85) who gave birth to a female child (p=0.002). The majority (91.7%; 78\\/85) had uncomplicated, term deliveries and normal birth weight neonates, with one quarter of the women previously delivered by Caesarean section. All had routine RM investigations and 19.0% (16\\/85) had an abnormal result. Fifty-seven women conceived again and 33.3% (19\\/57) miscarried, but there was no significant difference in failure rates between those with a previous male or female child (13\\/32 vs. 6\\/25, p=0.2). When patients with abnormal results were excluded, or when women with only one previous child were considered, there was still no difference in these rates. A previous male birth may be associated with an increased risk of secondary RM but numbers preclude concluding whether this increases recurrence risk. The suggested association with previous male birth provides a basis for further investigations at a molecular level.

  3. Secondary recurrent miscarriage is associated with previous male birth.

    LENUS (Irish Health Repository)

    Ooi, Poh Veh

    2012-01-31

    Secondary recurrent miscarriage (RM) is defined as three or more consecutive pregnancy losses after delivery of a viable infant. Previous reports suggest that a firstborn male child is associated with less favourable subsequent reproductive potential, possibly due to maternal immunisation against male-specific minor histocompatibility antigens. In a retrospective cohort study of 85 cases of secondary RM we aimed to determine if secondary RM was associated with (i) gender of previous child, maternal age, or duration of miscarriage history, and (ii) increased risk of pregnancy complications. Fifty-three women (62.0%; 53\\/85) gave birth to a male child prior to RM compared to 32 (38.0%; 32\\/85) who gave birth to a female child (p=0.002). The majority (91.7%; 78\\/85) had uncomplicated, term deliveries and normal birth weight neonates, with one quarter of the women previously delivered by Caesarean section. All had routine RM investigations and 19.0% (16\\/85) had an abnormal result. Fifty-seven women conceived again and 33.3% (19\\/57) miscarried, but there was no significant difference in failure rates between those with a previous male or female child (13\\/32 vs. 6\\/25, p=0.2). When patients with abnormal results were excluded, or when women with only one previous child were considered, there was still no difference in these rates. A previous male birth may be associated with an increased risk of secondary RM but numbers preclude concluding whether this increases recurrence risk. The suggested association with previous male birth provides a basis for further investigations at a molecular level.

  4. Is previous hyperthyroidism associated with long-term cognitive dysfunction?

    DEFF Research Database (Denmark)

    Lillevang-Johansen, Mads; Petersen, Inge; Christensen, Kaare

    2014-01-01

    OBJECTIVE: Hyperthyroidism has been suggested to adversely affect cognitive function. However, this association could also be caused by genetic and environmental factors affecting both the development of hyperthyroidism and cognitive functioning. By investigating twin pairs discordant...... for hyperthyroidism, this potential confounding can be minimized. The aim of the study was to examine if hyperthyroidism is associated with long-term cognitive dysfunction. DESIGN: Twin case-control study. PATIENTS: Twin pairs discordant for hyperthyroidism were identified by record-linkage between The Danish...... National Patient Registry and 3036 twin pairs from The Danish Twin Registry, who had participated in nationwide surveys on health conditions. MEASUREMENTS: Among other investigations, survey participants had carried out cognitive tests including a Mini-Mental State Exam (MMSE) and six separate cognitive...

  5. Pertussis-associated persistent cough in previously vaccinated children.

    Science.gov (United States)

    Principi, Nicola; Litt, David; Terranova, Leonardo; Picca, Marina; Malvaso, Concetta; Vitale, Cettina; Fry, Norman K; Esposito, Susanna

    2017-11-01

    To evaluate the role of Bordetella pertussis infection, 96 otherwise healthy 7- to 17-year-old subjects who were suffering from a cough lasting from 2 to 8 weeks were prospectively recruited. At enrolment, a nasopharyngeal swab and an oral fluid sample were obtained to search for pertussis infection by the detection of B. pertussis DNA and/or an elevated titre of anti-pertussis toxin IgG. Evidence of pertussis infection was found in 18 (18.7 %; 95 % confidence interval, 11.5-28.0) cases. In 15 cases, the disease occurred despite booster administration. In two cases, pertussis was diagnosed less than 2 years after the booster injection, whereas in the other cases it was diagnosed between 2 and 9 years after the booster dose. This study used non-invasive testing to show that pertussis is one of the most important causes of long-lasting cough in school-age subjects. Moreover, the protection offered by acellular pertussis vaccines currently wanes more rapidly than previously thought.

  6. Chronic impairments in spatial learning and memory in rats previously exposed to chlorpyrfos or diisopropylfluorophosphate.

    Science.gov (United States)

    Terry, A V; Beck, W D; Warner, S; Vandenhuerk, L; Callahan, P M

    2012-01-01

    The acute toxicity of organophosphates (OPs) has been studied extensively; however, much less attention has been given to the subject of repeated exposures that are not associated with overt signs of toxicity (i.e., subthreshold exposures). The objective of this study was to determine if the protracted spatial learning impairments we have observed previously after repeated subthreshold exposures to the insecticide chlorpyrifos (CPF) or the alkylphosphate OP, diisopropylfluorophosphate (DFP) persisted for longer periods after exposure. Male Wistar rats (beginning at two months of age) were initially injected subcutaneously with CPF (10.0 or 18.0mg/kg) or DFP (0.25 or 0.75 mg/kg) every other day for 30 days. After an extended OP-free washout period (behavioral testing begun 50 days after the last OP exposure), rats previously exposed to CPF, but not DFP, were impaired in a radial arm maze (RAM) win-shift task as well as a delayed non-match to position procedure. Later experiments (i.e., beginning 140 days after the last OP exposure) revealed impairments in the acquisition of a water maze hidden platform task associated with both OPs. However, only rats previously exposed to DFP were impaired in a second phase of testing when the platform location was changed (indicative of deficits of cognitive flexibility). These results indicate, therefore, that repeated, subthreshold exposures to CPF and DFP may lead to chronic deficits in spatial learning and memory (i.e., long after cholinesterase inhibition has abated) and that insecticide and alkylphosphate-based OPs may have differential effects depending on the cognitive domain evaluated. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Analysis of previous perceptual and motor experience in breaststroke kick learning

    Directory of Open Access Journals (Sweden)

    Ried Bettina

    2015-12-01

    Full Text Available One of the variables that influence motor learning is the learner’s previous experience, which may provide perceptual and motor elements to be transferred to a novel motor skill. For swimming skills, several motor experiences may prove effective. Purpose. The aim was to analyse the influence of previous experience in playing in water, swimming lessons, and music or dance lessons on learning the breaststroke kick. Methods. The study involved 39 Physical Education students possessing basic swimming skills, but not the breaststroke, who performed 400 acquisition trials followed by 50 retention and 50 transfer trials, during which stroke index as well as rhythmic and spatial configuration indices were mapped, and answered a yes/no questionnaire regarding previous experience. Data were analysed by ANOVA (p = 0.05 and the effect size (Cohen’s d ≥0.8 indicating large effect size. Results. The whole sample improved their stroke index and spatial configuration index, but not their rhythmic configuration index. Although differences between groups were not significant, two types of experience showed large practical effects on learning: childhood water playing experience only showed major practically relevant positive effects, and no experience in any of the three fields hampered the learning process. Conclusions. The results point towards diverse impact of previous experience regarding rhythmic activities, swimming lessons, and especially with playing in water during childhood, on learning the breaststroke kick.

  8. "My math and me": Nursing students' previous experiences in learning mathematics.

    Science.gov (United States)

    Røykenes, Kari

    2016-01-01

    In this paper, 11 narratives about former experiences in learning of mathematics written by nursing students are thematically analyzed. Most students had a positive relationship with the subject in primary school, when they found mathematics fun and were able to master the subject. For some, a change occurred in the transition to lower secondary school. The reasons for this change was found in the subject (increased difficulty), the teachers (movement of teachers, numerous substitute teachers), the class environment and size (many pupils, noise), and the student him- or herself (silent and anonymous pupil). This change was also found in the transition from lower to higher secondary school. By contrast, some students had experienced changes that were positive, and their mathematics teacher was a significant factor in this positive change. The paper emphasizes the importance of previous experiences in learning mathematics to nursing students when learning about drug calculation. Copyright © 2015. Published by Elsevier Ltd.

  9. Associative Learning Should Go Deep.

    Science.gov (United States)

    Mondragón, Esther; Alonso, Eduardo; Kokkola, Niklas

    2017-11-01

    Conditioning, how animals learn to associate two or more events, is one of the most influential paradigms in learning theory. It is nevertheless unclear how current models of associative learning can accommodate complex phenomena without ad hoc representational assumptions. We propose to embrace deep neural networks to negotiate this problem. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. TU-CD-BRD-01: Making Incident Learning Practical and Useful: Challenges and Previous Experiences

    International Nuclear Information System (INIS)

    Ezzell, G.

    2015-01-01

    aside for audience members to contribute to the discussion. Learning Objectives: Learn how to promote the use of an incident learning system in a clinic. Learn how to convert “event reporting” into “incident learning”. See examples of practice changes that have come out of learning systems. Learn how the RO-ILS system can be used as a primary internal learning system. Learn how to create succinct, meaningful reports useful to outside readers. Gary Ezzell chairs the AAPM committee overseeing RO-ILS and has received an honorarium from ASTRO for working on the committee reviewing RO-ILS reports. Derek Brown is a director of http://TreatSafely.org . Brett Miller has previously received travel expenses and an honorarium from Varian. Phillip Beron has nothing to report

  11. National Rates of Uterine Rupture are not Associated with Rates of Previous Caesarean Delivery

    DEFF Research Database (Denmark)

    Colmorn, Lotte B.; Langhoff-Roos, Jens; Jakobsson, Maija

    2017-01-01

    BACKGROUND: Previous caesarean delivery and intended mode of delivery after caesarean are well-known individual risk factors for uterine rupture. We examined if different national rates of uterine rupture are associated with differences in national rates of previous caesarean delivery and intende...

  12. High prevalence of genetic variants previously associated with LQT syndrome in new exome data

    DEFF Research Database (Denmark)

    Refsgaard, Lena; Holst, Anders G; Sadjadieh, Golnaz

    2012-01-01

    Exome Sequencing Project (ESP) has provided important knowledge on this topic. We aimed to investigate the prevalence of previously LQTS-associated variants in ESP (5400 individuals), in order to identify possible false-positive LQTS variants. With this aim, we performed a search for previously...... published LQTS-associated variants in ESP. In addition, a PolyPhen-2 prediction was conducted, and the four most prevalent LQTS-associated variants with significant functional effects present in ESP were genotyped in a second control population. We identified 33 missense variants previously associated...... with LQTS in ESP. These 33 variants affected 173 alleles and this corresponded to a LQTS prevalence of 1:31 in the ESP population. PolyPhen-2 predicted 30% of the 33 variants present in ESP to be benign compared with 13% among LQTS-associated variants not present in ESP (P=0.019). Genotyping of the four...

  13. Previous miscarriages and GLI2 are associated with anorectal malformations in offspring

    NARCIS (Netherlands)

    van de Putte, Romy; Wijers, Charlotte H. W.; de Blaauw, Ivo; Marcelis, Carlo L. M.; Sloots, Cornelius E. J.; Brooks, Alice S.; Broens, Paul M. A.; Roeleveld, Nel; van der Zanden, Loes F. M.; van Rooij, Iris A. L. M.

    2017-01-01

    STUDY QUESTION: Are anorectal malformations (ARMs) associated with previous miscarriages or single nucleotide polymorphisms (SNPs) in the Bone Morphogenetic Protein 4 (BMP4) and GLI family zinc finger 2 (GLI2) genes? SUMMARY ANSWER: The SNP rs3738880 in GLI2 and miscarriages were associated with

  14. The pathogenicity of genetic variants previously associated with left ventricular non-compaction

    DEFF Research Database (Denmark)

    Abbasi, Yeganeh; Jabbari, Javad; Jabbari, Reza

    2016-01-01

    an updated list of previously reported LVNC-associated variants with biologic description and investigate the prevalence of LVNC variants in healthy general population to find false-positive LVNC-associated variants. METHODS AND RESULTS: The Human Gene Mutation Database and PubMed were systematically...... searched to identify all previously reported LVNC-associated variants. Thereafter, the Exome Sequencing Project (ESP) and the Exome Aggregation Consortium (ExAC), that both represent the background population, was searched for all variants. Four in silico prediction tools were assessed to determine...

  15. The association between previous single first trimester abortion and pregnancy outcome in nulliparous women.

    Science.gov (United States)

    Hiersch, Liran; Ashwal, Eran; Aviram, Amir; Rayman, Shlomi; Wiznitzer, Arnon; Yogev, Yariv

    2016-01-01

    To determine the association between single previous abortion and pregnancy outcome in nulliparous women. A retrospective cohort study of all nulliparous women who delivered in a university-affiliated tertiary hospital (2009-2014). Pregnancy outcome of women with single previous first trimester abortion (study group) was compared to those of primigravida (control group). Of the 44 371 deliveries during the study period, 14 498 (32.6%) were of nulliparous women, of them 1501 (10.3%) had single previous abortion (abortion was independently associated with induction of labor (OR = 1.31, 95%C.I 1.04-1.63, p = 0.01), cesarean section (OR = 1.38, 95%C.I 1.18-1.60, p abortion no difference in pregnancy outcome was observed between those with previous induced termination of pregnancy and spontaneous abortion, except for increased risk for retained placenta in those with previous spontaneous abortion. Single early previous abortion in nulliparous women was associated with higher rate of induction of labor, cesarean section and retained placenta compared to primigravida women.

  16. Adolescents' physical activity is associated with previous and current physical activity practice by their parents.

    Science.gov (United States)

    Christofaro, Diego Giulliano Destro; Andersen, Lars Bo; Andrade, Selma Maffei de; Barros, Mauro Virgílio Gomes de; Saraiva, Bruna Thamyres Ciccotti; Fernandes, Rômulo Araújo; Ritti-Dias, Raphael Mendes

    The purpose of this study was to determine whether parents' current and previous physical activity practice is associated with adolescents' physical activity. The sample was composed of 1231 adolescents (14-17 years), and 1202 mothers and 871 fathers were interviewed. Weight and height of the adolescents were measured. Self-reported parents' weight and height were obtained. The current and previous physical activity levels (Baecke's questionnaire) of parents (during childhood and adolescence) and adolescents' physical activity levels were obtained using a questionnaire. The magnitude of the associations between parent and adolescent physical activity levels was determined by binary logistic regression (adjusted by sex, age, and socioeconomic level of adolescents and education level of parents). The current physical activity practice by parents was associated with adolescents' physical activity (pparents in their childhood and adolescence were also associated with higher physical activity levels among adolescents. Adolescents whose parents were both physically active in the past and present were six times (OR=6.67 [CI=1.94-22.79]) more likely to be physically active compared to adolescents with no parents who were physically active in the past. The current and previous physical activities of parents were associated with higher levels of physical activity in adolescents, even after controlling for confounding factors. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  17. Adolescents' physical activity is associated with previous and current physical activity practice by their parents

    Directory of Open Access Journals (Sweden)

    Diego Giulliano Destro Christofaro

    Full Text Available Abstract Objective: The purpose of this study was to determine whether parents' current and previous physical activity practice is associated with adolescents' physical activity. Methods: The sample was composed of 1231 adolescents (14-17 years, and 1202 mothers and 871 fathers were interviewed. Weight and height of the adolescents were measured. Self-reported parents' weight and height were obtained. The current and previous physical activity levels (Baecke's questionnaire of parents (during childhood and adolescence and adolescents' physical activity levels were obtained using a questionnaire. The magnitude of the associations between parent and adolescent physical activity levels was determined by binary logistic regression (adjusted by sex, age, and socioeconomic level of adolescents and education level of parents. Results: The current physical activity practice by parents was associated with adolescents' physical activity (p < 0.001. The physical activities reported by parents in their childhood and adolescence were also associated with higher physical activity levels among adolescents. Adolescents whose parents were both physically active in the past and present were six times (OR = 6.67 [CI = 1.94-22.79] more likely to be physically active compared to adolescents with no parents who were physically active in the past. Conclusions: The current and previous physical activities of parents were associated with higher levels of physical activity in adolescents, even after controlling for confounding factors.

  18. Association between previous splenectomy and gastric dilatation-volvulus in dogs: 453 cases (2004-2009).

    Science.gov (United States)

    Sartor, Angela J; Bentley, Adrienne M; Brown, Dorothy C

    2013-05-15

    To evaluate the association between previous splenectomy and gastric dilatation-volvulus (GDV) in dogs. Multi-institutional retrospective case-control study. Animals-151 dogs treated surgically for GDV and 302 control dogs with no history of GDV. Computerized records of dogs evaluated via exploratory laparotomy or abdominal ultrasonography were searched, and dogs with GDV and dogs without GDV (control dogs) were identified. Two control dogs were matched with respect to age, body weight, sex, neuter status, and breed to each dog with GDV. Data were collected on the presence or absence of the spleen for both dogs with GDV and control dogs. Conditional logistic regression analysis was used to investigate the association of previous splenectomy with GDV. 6 (4%) dogs in the GDV group and 3 (1%) dogs in the control group had a history of previous splenectomy. The odds of GDV in dogs with a history of previous splenectomy in this population of dogs were 5.3 times those of dogs without a history of previous splenectomy (95% confidence interval, 1.1 to 26.8). For the patients in the present study, there was an increased odds of GDV in dogs with a history of splenectomy. Prophylactic gastropexy may be considered in dogs undergoing a splenectomy, particularly if other risk factors for GDV are present.

  19. ERP correlates of associative learning.

    Science.gov (United States)

    Rose, M; Verleger, R; Wascher, E

    2001-05-01

    We examined changes of event-related potentials (ERPs) while participants learned stimulus-to-stimulus relations in an S1-S2 task. The design allowed for separating processes of associative learning from nonspecific effects. Participants had to respond to S2 by a left or right key-press dependent on S2 identity (letter W or M). Preparation for S2 could be improved by using the associative information given by S1. The S1 was an arrow pointing to the left or right. In combination with its color, arrow direction was informative about location and identity of S2, but participants were not informed about the relevance of color. Arrows in two of the colors were fully predictive for the S2 whereas the third color gave no valid information. This third stimulus controlled for habituation and procedural learning. Six blocks with 200 trials each and all three S1 colors in random order were presented. Behavioral and ERP differences in each block between "learning" and control trials were used to identify processes of associative learning. Several effects of associative learning were identified indicating the involvement of specific stages of information processing: a continuous increase of P3 amplitude evoked by S1 was accompanied by a decrease of P3 evoked by S2. These changes reflected the modifications of stimulus weights for response selection and the strengthened association between the two stimulus complexes in the time course of learning. The related motor preparation benefited from learning too, expressed in a decrease of CNV amplitude and an increase of LRP amplitude. Finally a decrease of N1 amplitude evoked by S2 indicated the reduced need to allocate spatial attention to the S2 location according to the learned meaning of S1.

  20. Association between obstetric complications & previous pregnancy outcomes with current pregnancy outcomes in Uttar Pradesh, India.

    Science.gov (United States)

    Singh, Deepti; Goli, Srinivas; Parsuraman, Sulabha

    2014-01-01

    A substantial proportion of pregnant women in India are at the risk of serious obstetric complications and reliable information on obstetric morbidity is scanty, particularly in socio-economically disadvantaged society. We studied the association between the obstetric complications in women in their current pregnancy and adverse pregnancy outcomes in previous pregnancies in Uttar Pradesh, India. Data from District Level Household Survey (2007-2008) were used for empirical assessment. Bivariate, trivariate and Cox proportional hazard regression model analyses were applied to examine the effect of obstetric complications and previous pregnancy outcome on current pregnancy outcome among currently married women (age group 15-49 yr) in Uttar Pradesh, India. The results of this study showed that the obstetric complications in the current pregnancy and adverse pregnancy outcomes in previous pregnancies were associated with the outcome of the current pregnancy. Cox proportional hazard regression model estimates revealed that the hazard ratio of having stillbirths were significantly higher among women with any obstetric complications compared to women with no obstetric complications. The adverse pregnancy outcome in a previous pregnancy was the largest risk factor for likelihood of developing similar type of adverse pregnancy outcome in the current pregnancy. The findings provided key insights for health policy interventions in terms of prevention of obstetric complications to avoid the adverse pregnancy outcome in women.

  1. Association of Aortic Valve Sclerosis with Previous Coronary Artery Disease and Risk Factors

    Directory of Open Access Journals (Sweden)

    Filipe Carvalho Marmelo

    2014-11-01

    Full Text Available Background: Aortic valve sclerosis (AVS is characterized by increased thickness, calcification and stiffness of the aortic leaflets without fusion of the commissures. Several studies show an association between AVS and presence of coronary artery disease. Objective: The aim of this study is to investigate the association between presence of AVS with occurrence of previous coronary artery disease and classical risk factors. Methods: The sample was composed of 2,493 individuals who underwent transthoracic echocardiography between August 2011 and December 2012. The mean age of the cohort was 67.5 ± 15.9 years, and 50.7% were female. Results: The most frequent clinical indication for Doppler echocardiography was the presence of stroke (28.8%, and the most common risk factor was hypertension (60.8%. The most prevalent pathological findings on Doppler echocardiography were mitral valve sclerosis (37.1% and AVS (36.7%. There was a statistically significant association between AVS with hypertension (p < 0.001, myocardial infarction (p = 0.007, diabetes (p = 0.006 and compromised left ventricular systolic function (p < 0.001. Conclusion: Patients with AVS have higher prevalences of hypertension, stroke, hypercholesterolemia, myocardial infarction, diabetes and compromised left ventricular systolic function when compared with patients without AVS. We conclude that there is an association between presence of AVS with previous coronary artery disease and classical risk factors.

  2. Muir-Torre syndrome-associated pleomorphic liposarcoma arising in a previous radiation field.

    Science.gov (United States)

    Yozu, Masato; Symmans, Pennie; Dray, Michael; Griffin, Jennifer; Han, Catherine; Ng, Daniel; Parry, Susan; Wong, Kp

    2013-03-01

    Muir-Torre syndrome is a variant of Lynch syndrome, characterised by sebaceous neoplasia and/or keratoacanthomas associated with visceral malignancies. Muir-Torre syndrome is caused by germline mutations of one of the mismatch repair genes, frequently MSH2 and less frequently MLH1 and MSH6. Visceral malignancies associated with Muir-Torre syndrome and Lynch syndrome include colorectal, endometrial and other gastrointestinal, urological and gynaecological malignancies. Small numbers of Lynch syndrome-associated soft tissue sarcomas have been reported, but there are no reported cases of soft tissue sarcomas in Muir-Torre syndrome. In this study, we report a 74-year-old man with known Muir-Torre syndrome with confirmed MSH2 germline mutation, diagnosed with pleomorphic liposarcoma of the right buttock in a previous radiation field. The tumour showed loss of expression of MSH2 and MSH6 on immunohistochemistry. Immunohistochemistry on another pleomorphic liposarcoma in a different patient with no previous history of Muir-Torre syndrome or Lynch syndrome showed no loss of expression of mismatch repair proteins. This is the first report of Muir-Torre syndrome-associated sarcoma and the first case of post-radiation sarcoma in Lynch syndrome.

  3. Association between previous spontaneous abortion and pre-eclampsia during a subsequent pregnancy.

    Science.gov (United States)

    Sepidarkish, Mahdi; Almasi-Hashiani, Amir; Maroufizadeh, Saman; Vesali, Samira; Pirjani, Reihaneh; Samani, Reza O

    2017-01-01

    To determine the impact of a history of spontaneous abortion on pre-eclampsia during a subsequent pregnancy. A cross-sectional study enrolled pregnant women admitted to obstetrics and gynecology wards at 103 hospitals in Tehran, Iran for delivery between July 6 and July 21, 2015. Consenting participants were interviewed by midwives; data were collected using a five-part questionnaire and patients' medical records were retrieved. Patient data were analyzed by multiple logistic regression to identify variables associated with increased odds of pre-eclampsia. In total, 5170 patients were interviewed and 252 had experienced pre-eclampsia. The number of previous spontaneous abortions was found to be associated with pre-eclampsia, and a higher number of previous spontaneous abortions was associated with increased odds of patients having experienced pre-eclampsia (adjusted odds ratio 1.28, 95% confidence interval 1.03-1.59; P=0.025). A history of spontaneous abortion was associated with increased odds of pre-eclampsia during a subsequent pregnancy. © 2016 International Federation of Gynecology and Obstetrics.

  4. The Founding of the Learning Communities Association

    Science.gov (United States)

    Huerta, Juan Carlos

    2017-01-01

    Learning communities have reached the point in their growth that we now need a professional association to allow for more opportunities for participation in advancing learning communities. This is the story of the founding of the new Learning Communities Association.

  5. Unsupervised learning of complex associations in an animal model.

    Science.gov (United States)

    Castro, Leyre; Wasserman, Edward A; Lauffer, Marisol

    2018-04-01

    Supervised learning results from explicit corrective feedback, whereas unsupervised learning results from statistical co-occurrence. In an initial training phase, we gave pigeons an unsupervised learning task to see if mere pairing could establish associations between multiple pairs of visual images. To assess learning, we administered occasional testing trials in which pigeons were shown an object and had to choose between previously paired and unpaired tokens. Learning was evidenced by preferential choice of the previously unpaired token. In a subsequent supervised training phase, learning was facilitated if the object and token had previously been paired. These results document unsupervised learning in pigeons and resemble statistical learning in infants, suggesting an important parallel between human and animal cognition. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. A Latin Functionalist Dictionary as a Self-Learning Language Device: Previous Experiences to Digitalization

    Science.gov (United States)

    Márquez, Manuel; Chaves, Beatriz

    2016-01-01

    The application of a methodology based on S.C. Dik's Functionalist Grammar linguistic principles, which is addressed to the teaching of Latin to secondary students, has resulted in a quantitative improvement in students' acquisition process of knowledge. To do so, we have used a self-learning tool, an ad hoc dictionary, of which the use in…

  7. Rising frequency of placenta previa and associated morbidity in women with previous casearean section

    International Nuclear Information System (INIS)

    Akhter, F.; Nawaz, Q.; Mushtaq, Q.U.A.

    2015-01-01

    To determine rising frequency of placenta previa and its associated morbidity in women with previous caesarean section. Study Design: Cross sectional study. Place and Duration of Study: This study was conducted in the Department of Obstetrics and Gynecology at CMH Kohat from Jul 2010 to Jun 2011. Patients and Methods: This study included all pregnant women undergoing repeat caesarean sections. Of these, total 74 patients were admitted with placenta previa. The frequency and associated morbidity were determined. Results: In our study 74 patients with placenta previa were included. 71.62% were less than 35 yrs of age, while 28.38% were equal to or more than 35 years. The gestational age at presentation was 24-36 weeks in 74.3% and 37 + weeks in 5.7% at presentation, 89% patients were symptomatic and 11% were asympyomatic. The morbidities observed were placenta accrete 47%, urinary tract trauma in 63.51%, caesarean hysterectomy in 62.16%, post operative febrile morbidity in 77.03%, maternal mortality was nil, paralytic ileus in 28.38%, PPH in 82.43%, surgical site infection in 16.21%. Conclusion: Frequency of placenta previa and its associated morbidity was raised due to repeated caesarean section rate which must be reduced to decrease maternal morbidity and mortality. (author)

  8. A Latin Functionalist Dictionary as a Self-Learning Language Device: Previous Experiences to Digitalization

    Directory of Open Access Journals (Sweden)

    Cruz Manuel Márquez

    2016-07-01

    Full Text Available The application of a methodology based on S.C. Dik’s Functionalist Grammar linguistic principles, which is addressed to the teaching of Latin to secondary students, has resulted in a quantitative improvement in students’ acquisition process of knowledge. To do so, we have used a self-learning tool, an ad hoc dictionary, of which the use in different practices has made students understand, at a basic level, the functioning of this language.

  9. Understanding infants' and children's social learning about foods: previous research and new prospects.

    Science.gov (United States)

    Shutts, Kristin; Kinzler, Katherine D; DeJesus, Jasmine M

    2013-03-01

    Developmental psychologists have devoted significant attention to investigating how children learn from others' actions, emotions, and testimony. Yet most of this research has examined children's socially guided learning about artifacts. The present article focuses on a domain that has received limited attention from those interested in the development of social cognition: food. We begin by reviewing the available literature on infants' and children's development in the food domain and identify situations in which children evidence both successes and failures in their interactions with foods. We focus specifically on the role that other people play in guiding what children eat and argue that understanding patterns of successes and failures in the food domain requires an appreciation of eating as a social phenomenon. We next propose a series of questions for future research and suggest that examining food selection as a social phenomenon can shed light on mechanisms underlying children's learning from others and provide ideas for promoting healthy social relationships and eating behaviors early in development.

  10. Association between urinary incontinence in women and a previous history of surgery

    DEFF Research Database (Denmark)

    Mommsen, S.; Foldspang, Anders; Elving, L.

    1993-01-01

    In a cross-sectional study, 85% of 3114 women responded to a questionnaire on urinary incontinence and a history of abdominal, gynaecological and urological surgery. In 1987 the prevalence of urinary incontinence was 17%; 63% had undergone surgery, mainly gynaecological, and almost one-third of t......In a cross-sectional study, 85% of 3114 women responded to a questionnaire on urinary incontinence and a history of abdominal, gynaecological and urological surgery. In 1987 the prevalence of urinary incontinence was 17%; 63% had undergone surgery, mainly gynaecological, and almost one......-third of the respondents had had more than one operation. Bivariate and multivariate analysis showed stress urinary incontinence to be associated with previous exposure to surgery....

  11. Previous PICC placement may be associated with catheter-related infections in hemodialysis patients.

    Science.gov (United States)

    Butler, Philip J; Sood, Shreya; Mojibian, Hamid; Tal, Michael G

    2011-02-01

    Catheter-related infections (CRIs) are a significant source of morbidity and mortality in hemodialysis patients. The identification of novel, modifiable risk factors for CRIs may lead to improved outcomes in this population. Peripherally inserted central catheters (PICCs) have been hypothesized to compromise vascular access due to vascular damage and venous thrombosis, whereas venous thrombosis has been linked to the development of CRIs. Here we examine the association between PICC placement and CRIs. A retrospective review was performed of all chronic hemodialysis catheter placements and exchanges performed at a large university hospital from September 2003 to September 2008. History of PICC line use was determined by examining hospital radiologic records from December 1993 to September 2008. Catheter-related complications were assessed and correlated with PICC line history. One hundred eighty-five patients with 713 chronic tunneled hemodialysis catheter placements were identified. Thirty-eight of those patients (20.5%) had a history of PICC placement; these patients were more likely to have CRIs (odds ratio = 2.46, 95% confidence interval = 1.71-3.53, p PICC placement. There was no difference between the two groups in age or number of catheters placed. Previous PICC placement may be associated with catheter-related infections in hemodialysis patients.

  12. Previous PICC Placement May Be Associated With Catheter-Related Infections in Hemodialysis Patients

    International Nuclear Information System (INIS)

    Butler, Philip J.; Sood, Shreya; Mojibian, Hamid; Tal, Michael G.

    2011-01-01

    Background: Catheter-related infections (CRIs) are a significant source of morbidity and mortality in hemodialysis patients. The identification of novel, modifiable risk factors for CRIs may lead to improved outcomes in this population. Peripherally inserted central catheters (PICCs) have been hypothesized to compromise vascular access due to vascular damage and venous thrombosis, whereas venous thrombosis has been linked to the development of CRIs. Here we examine the association between PICC placement and CRIs. Methods: A retrospective review was performed of all chronic hemodialysis catheter placements and exchanges performed at a large university hospital from September 2003 to September 2008. History of PICC line use was determined by examining hospital radiologic records from December 1993 to September 2008. Catheter-related complications were assessed and correlated with PICC line history. Results: One hundred eighty-five patients with 713 chronic tunneled hemodialysis catheter placements were identified. Thirty-eight of those patients (20.5%) had a history of PICC placement; these patients were more likely to have CRIs (odds ratio = 2.46, 95% confidence interval = 1.71–3.53, p < .001) compared with patients without a history of PICC placement. There was no difference between the two groups in age or number of catheters placed. Conclusion: Previous PICC placement may be associated with catheter-related infections in hemodialysis patients.

  13. Molecular characterization of previously elusive badnaviruses associated with symptomatic cacao in the New World.

    Science.gov (United States)

    Chingandu, Nomatter; Zia-Ur-Rehman, Muhammad; Sreenivasan, Thyail N; Surujdeo-Maharaj, Surendra; Umaharan, Pathmanathan; Gutierrez, Osman A; Brown, Judith K

    2017-05-01

    Suspected virus-like symptoms were observed in cacao plants in Trinidad during 1943, and the viruses associated with these symptoms were designated as strains A and B of cacao Trinidad virus (CTV). However, viral etiology has not been demonstrated for either phenotype. Total DNA was isolated from symptomatic cacao leaves exhibiting the CTV A and B phenotypes and subjected to Illumina HiSeq and Sanger DNA sequencing. Based on de novo assembly, two apparently full-length badnavirus genomes of 7,533 and 7,454 nucleotides (nt) were associated with CTV strain A and B, respectively. The Trinidad badnaviral genomes contained four open reading frames, three of which are characteristic of other known badnaviruses, and a fourth that is present in only some badnaviruses. Both badnaviral genomes harbored hallmark caulimovirus-like features, including a tRNA Met priming site, a TATA box, and a polyadenylation-like signal. Pairwise comparisons of the RT-RNase H region indicated that the Trinidad isolates share 57-71% nt sequence identity with other known badnaviruses. Based on the system for badnavirus species demarcation in which viruses with less than 80% nt sequence identity in the RT-RNase gene are considered members of separate species, these isolates represent two previously unidentified badnaviruses, herein named cacao mild mosaic virus and cacao yellow vein banding virus, making them the first cacao-infecting badnaviruses identified thus far in the Western Hemisphere.

  14. Learning in rich networks involves both positive and negative associations.

    Science.gov (United States)

    Roembke, Tanja C; Wasserman, Edward A; McMurray, Bob

    2016-08-01

    Adaptive behaviors are believed to be shaped by both positive (the strengthening of correct associations) and negative (the pruning of incorrect associations or the building of inhibitory associations) forms of associative learning. However, there has been little direct documentation of how these basic processes participate in the learning of rich associative networks that support cognitive behaviors like categorization. Although negative associative learning is an important component of theories of development, it is not clear whether it involves acquiring specific (experience-dependent) content or represents a more general aspect of (experience-expectant) development. The authors thus trained pigeons on a complex many-to-many learning paradigm previously established as an analog to human word learning. Pigeons learned to map 16 objects onto 16 distinct report tokens; the authors manipulated the amount of negative associative learning that could occur by restricting which tokens were available as incorrect options. In testing, accuracy was lower on trials with foils that had not been presented with a target than on trials with previously experienced foils. Moreover, when the correct token was withheld, pigeons preferred foils novel to the target object over previously experienced foils. A second experiment replicated these results and further found that these effects only emerged after some positive associations had been acquired. Findings indicate that the learning of rich associative networks does not depend solely on positive associative learning, but also on negative associative learning; this conclusion has important implications for basic learning theories in both animals and humans, as well as for theories of development. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  15. Risk Communication Strategies: Lessons Learned from Previous Disasters with a Focus on the Fukushima Radiation Accident.

    Science.gov (United States)

    Svendsen, Erik R; Yamaguchi, Ichiro; Tsuda, Toshihide; Guimaraes, Jean Remy Davee; Tondel, Martin

    2016-12-01

    It has been difficult to both mitigate the health consequences and effectively provide health risk information to the public affected by the Fukushima radiological disaster. Often, there are contrasting public health ethics within these activities which complicate risk communication. Although no risk communication strategy is perfect in such disasters, the ethical principles of risk communication provide good practical guidance. These discussions will be made in the context of similar lessons learned after radiation exposures in Goiania, Brazil, in 1987; the Chernobyl nuclear power plant accident, Ukraine, in 1986; and the attack at the World Trade Center, New York, USA, in 2001. Neither of the two strategies is perfect nor fatally flawed. Yet, this discussion and lessons from prior events should assist decision makers with navigating difficult risk communication strategies in similar environmental health disasters.

  16. Mirror Neurons from Associative Learning

    OpenAIRE

    Catmur, Caroline; Press, Clare; Heyes, Cecilia

    2016-01-01

    Mirror neurons fire both when executing actions and observing others perform similar actions. Their sensorimotor matching properties have generally been considered a genetic adaptation for social cognition; however, in the present chapter we argue that the evidence in favor of this account is not compelling. Instead we present evidence supporting an alternative account: that mirror neurons’ matching properties arise from associative learning during individual development. Notably, this proces...

  17. Visual associative learning in wood ants.

    Science.gov (United States)

    Fernandes, A Sofia D; Buckley, Christopher L; Niven, Jeremy E

    2018-02-07

    Wood ants are a model system for studying visual learning and navigation. They can forage for food and navigate to their nests effectively by forming memories of visual features in their surrounding environment. Previous studies of freely behaving ants have revealed many of the behavioural strategies and environmental features necessary for successful navigation. However, little is known about the exact visual properties of the environment that animals learn or the neural mechanisms that allow them to achieve this. As a first step towards addressing this, we developed a classical conditioning paradigm for visual learning in harnessed wood ants that allows us to control precisely the learned visual cues. In this paradigm, ants are fixed and presented with a visual cue paired with an appetitive sugar reward. Using this paradigm, we found that visual cues learnt by wood ants through Pavlovian conditioning are retained for at least 1 h. Furthermore, we found that memory retention is dependent upon the ants' performance during training. Our study provides the first evidence that wood ants can form visual associative memories when restrained. This classical conditioning paradigm has the potential to permit detailed analysis of the dynamics of memory formation and retention, and the neural basis of learning in wood ants. © 2018. Published by The Company of Biologists Ltd.

  18. Toothbrushing procedure in schoolchildren with no previous formal instruction: variables associated to dental biofilm removal.

    Science.gov (United States)

    Rossi, Glenda N; Sorazabal, Ana L; Salgado, Pablo A; Squassi, Aldo F; Klemonskis, Graciela L

    2016-04-01

    The aim of this study was to establish the association between features regarding brushing procedure performed by schoolchildren without previous formal training and the effectiveness of biofilm removal. Out of a population of 8900 6- and 7-year-old schoolchildren in Buenos Aires City, 600 children were selected from schools located in homogeneous risk areas. Informed consent was requested from parents or guardians and formal assent was obtained from children themselves. The final sample consisted of 316 subjects. The following tooth brushing variables were analyzed: toothbrush-gripping, orientation of active part of bristles with respect to the tooth, type of movement applied, brushing both jaws together or separately, including all 6 sextants and duration of brushing. The level of dental biofilm after brushing was determined by O'Leary's index, acceptable cut-off point = 20%. Four calibrated dentists performed observations and clinical examinations. Frequency distribution, central tendency and dispersion measures were calculated. Cluster analyses were performed; proportions of variables for each cluster were compared with Bonferroni's correction and OR was obtained. The most frequent categories were: palm gripping (71.51%); perpendicular orientation (85.8%); horizontal movement (95.6%); separate addressing of jaws (68%) and inclusion of all 6 sextants (50.6%). Mean duration of brushing was 48.78 ± 27.36 seconds. 42.7% of the children achieved an acceptable biofilm level. The cluster with the highest proportion of subjects with acceptable post-brushing biofilm levels (p<0.05) differed significantly from the rest for the variable "inclusion of all 6 sextants in brushing procedure". OR was 2.538 (CI 95% 1.603 - 4.017). Inclusion of all six sextants could be a determinant variable for the removal of biofilm by brushing in schoolchildren, and should be systematized as a component in oral hygiene education. Sociedad Argentina de Investigación Odontológica.

  19. Definitions of Sarcopenia: Associations with Previous Falls and Fracture in a Population Sample.

    Science.gov (United States)

    Clynes, M A; Edwards, M H; Buehring, B; Dennison, E M; Binkley, N; Cooper, C

    2015-11-01

    Sarcopenia is common in later life and may be associated with adverse health outcomes such as disability, falls and fracture. There is no consensus definition for its diagnosis although diagnostic algorithms have been proposed by the European Working Group for Sarcopenia in Older People (EWGSOP), the International Working Group on Sarcopenia (IWGS) and the Foundation for the National Institutes of Health Sarcopenia Project (FNIH). More recently, Binkley and colleagues devised a score-based system for the diagnosis of "dysmobility syndrome" in an attempt to combine adverse musculoskeletal phenotypes, including sarcopenia and osteoporosis, in order to identify older individuals at particular risk. We applied these criteria to participants from the Hertfordshire Cohort Study to define their prevalence in an unselected cohort of UK community-dwelling older adults and assess their relationships with previous falls and fracture. Body composition and areal bone mineral density were measured using dual-energy X-ray absorptiometry, gait speed was determined by a 3-m walk test and grip strength was assessed with a Jamar hand-held dynamometer. Researcher-administered questionnaires were completed detailing falls and fracture history. The prevalence of sarcopenia in this cohort was 3.3, 8.3 and 2.0% using the EWGSOP, IWGS and related definition of FNIH, respectively; 24.8% of individuals had dysmobility syndrome. Individuals with dysmobility reported significantly higher number of falls (last year and since the age of 45 years) (p definition was applied. The IWGS definition of sarcopenia appears to be an effective means of identifying individuals at risk of prevalent adverse musculoskeletal events.

  20. Prevention of Tetanus Outbreak Following Natural Disaster in Indonesia: Lessons Learned from Previous Disasters.

    Science.gov (United States)

    Pascapurnama, Dyshelly Nurkartika; Murakami, Aya; Chagan-Yasutan, Haorile; Hattori, Toshio; Sasaki, Hiroyuki; Egawa, Shinichi

    2016-03-01

    In Indonesia, the Aceh earthquake and tsunami in 2004 killed 127,000 people and caused half a million injuries, while the Yogyakarta earthquake in 2006 caused 5,700 deaths and 37,000 injuries. Because disaster-affected areas are vulnerable to epidemic-prone diseases and tetanus is one such disease that is preventable, we systematically reviewed the literature related to tetanus outbreaks following previous two natural disasters in Indonesia. Based on our findings, recommendations for proper vaccination and education can be made for future countermeasures. Using specified keywords related to tetanus and disasters, relevant documents were screened from PubMed, the WHO website, and books. Reports offering limited data and those released before 2004 were excluded. In all, 16 publications were reviewed systematically. Results show that 106 cases of tetanus occurred in Aceh, with a case fatality ratio (CFR) of 18.9%; 71 cases occurred in Yogyakarta, with CFR of 36.6%. For both outbreaks, most patients had been wounded during scavenging or evacuation after the disaster occurred. Poor access to health care because of limited transportation or hospital facilities, and low vaccination coverage and lack of awareness of tetanus risk contributed to delayed treatment and case severity. Tetanus outbreaks after disasters are preventable by increasing vaccination coverage, improving wound care treatment, and establishing a regular surveillance system, in addition to good practices of disaster management and supportive care following national guidelines. Furthermore, health education for communities should be provided to raise awareness of tetanus risk reduction.

  1. Learning Disabilities Association of America

    Science.gov (United States)

    ... for information on learning disabilities. Learn more about: Auditory Processing Disorder Dyscalculia Dysgraphia Dyslexia Dyspraxia Language Processing Disorder Non-Verbal Learning Disabilities Visual Perceptual/Visual Motor Deficit Memory ADHD Executive Functioning Parents LD/ADHD Basics Assessment & ...

  2. Knee Osteoarthritis Is Associated With Previous Meniscus and Anterior Cruciate Ligament Surgery Among Elite College American Football Athletes

    OpenAIRE

    Smith, Matthew V.; Nepple, Jeffrey J.; Wright, Rick W.; Matava, Matthew J.; Brophy, Robert H.

    2016-01-01

    Background: Football puts athletes at risk for knee injuries such meniscus and anterior cruciate ligament (ACL) tears, which are associated with the development of osteoarthritis (OA). Previous knee surgery, player position, and body mass index (BMI) may be associated with knee OA. Hypothesis: In elite football players undergoing knee magnetic resonance imaging at the National Football League’s Invitational Combine, the prevalence of knee OA is associated with previous knee surgery and BMI. S...

  3. Orchidopexy in late childhood often associated with previously normal testicular position.

    Science.gov (United States)

    van der Plas, Evelyn; Zijp, Gerda; Froeling, Frank; de Wilde, Jeroen; van der Voort, Laszla; Hack, Wilfried

    2013-08-01

    The aim of this study was to determine retrospectively, the prevalence of acquired undescended testis (UDT) in boys who underwent late orchidopexies, that is, performed after the age of 2 years. We included all patients who were 2 years or older when they underwent orchidopexy (ORP) for UDT at the Juliana Children's Hospital during 1996 to 2009. Previous testis position from birth until the date of ORP was obtained from youth health care records. We identified 660 boys who underwent ORP after the age of 2 years for undescended testis. For 421 of these 660 boys, the previous testicular position could be retrieved from the health records. In 143 of these 421 boys (34%), the operated testis had never been scrotal (congenital UDT), whereas in the other 278 boys (66%), a previous scrotal position had been documented twice or more (acquired UDT). Our results show that two-thirds of the boys that underwent ORP after the age of 2 had previously normal descended testes. This finding may offer an additional explanation for the discrepancy between the incidence of congenital UDT and the high rate of ORP in mid and late childhood. Georg Thieme Verlag KG Stuttgart · New York.

  4. Active Learning Not Associated with Student Learning in a Random Sample of College Biology Courses

    Science.gov (United States)

    Andrews, T. M.; Leonard, M. J.; Colgrove, C. A.; Kalinowski, S. T.

    2011-01-01

    Previous research has suggested that adding active learning to traditional college science lectures substantially improves student learning. However, this research predominantly studied courses taught by science education researchers, who are likely to have exceptional teaching expertise. The present study investigated introductory biology courses randomly selected from a list of prominent colleges and universities to include instructors representing a broader population. We examined the relationship between active learning and student learning in the subject area of natural selection. We found no association between student learning gains and the use of active-learning instruction. Although active learning has the potential to substantially improve student learning, this research suggests that active learning, as used by typical college biology instructors, is not associated with greater learning gains. We contend that most instructors lack the rich and nuanced understanding of teaching and learning that science education researchers have developed. Therefore, active learning as designed and implemented by typical college biology instructors may superficially resemble active learning used by education researchers, but lacks the constructivist elements necessary for improving learning. PMID:22135373

  5. Active learning not associated with student learning in a random sample of college biology courses.

    Science.gov (United States)

    Andrews, T M; Leonard, M J; Colgrove, C A; Kalinowski, S T

    2011-01-01

    Previous research has suggested that adding active learning to traditional college science lectures substantially improves student learning. However, this research predominantly studied courses taught by science education researchers, who are likely to have exceptional teaching expertise. The present study investigated introductory biology courses randomly selected from a list of prominent colleges and universities to include instructors representing a broader population. We examined the relationship between active learning and student learning in the subject area of natural selection. We found no association between student learning gains and the use of active-learning instruction. Although active learning has the potential to substantially improve student learning, this research suggests that active learning, as used by typical college biology instructors, is not associated with greater learning gains. We contend that most instructors lack the rich and nuanced understanding of teaching and learning that science education researchers have developed. Therefore, active learning as designed and implemented by typical college biology instructors may superficially resemble active learning used by education researchers, but lacks the constructivist elements necessary for improving learning.

  6. Transfer of dimensional associability in human contingency learning.

    Science.gov (United States)

    Kattner, Florian; Green, C Shawn

    2016-01-01

    Several studies have demonstrated processing advantages for stimuli that were experienced to be reliable predictors of an outcome relative to other stimuli. The present study tested whether such increases in associability apply at the level of entire stimulus dimensions (as suggested by Sutherland & Mackintosh, 1971). In 4 experiments, participants had to learn associations between Gabor gratings and particular responses. In a first experiment, some gratings were more predictive of the response than other gratings, whereas in 3 subsequent experiments, one stimulus dimension (i.e., either the orientation or spatial frequency of the grating) was more predictive than the other dimension. In contrast to the learned predictiveness of individual gratings (Experiment 1), dimensional predictiveness did not affect the subsequent rate of learning (Experiments 2 and 3), suggesting changes in the associability of specific stimuli, but not of stimulus dimensions. Moreover, greater transfer of predictiveness was found in all experiments when particular stimulus values of the test discrimination did not lie between the previously relevant stimuli. In Experiment 4, an increased learning rate was found for discriminations along the previously predictive dimension compared with a dimension that was indicative of uncertainty, but again the transfer was more pronounced for specific stimuli that were compatible with the previously learned discrimination. Taken together, the results imply that a transfer of associability typically applies to individual stimuli and depends on how the transfer stimuli relate to those stimuli that individuals previously learned to attend. (c) 2016 APA, all rights reserved).

  7. Thyroid disease awareness is associated with high rates of identifying subjects with previously undiagnosed thyroid dysfunction.

    Science.gov (United States)

    Canaris, Gay J; Tape, Thomas G; Wigton, Robert S

    2013-04-16

    Conventional screening for hypothyroidism is controversial. Although hypothyroidism is underdiagnosed, many organizations do not recommend screening, citing low disease prevalence in unselected populations. We studied attendees at a thyroid health fair, hypothesizing that certain patient characteristics would enhance the yield of testing. We carried out an observational study of participants at a Michigan health fair that focused on thyroid disease. We collected patient-reported symptoms and demographics by questionnaire, and correlated these with the TSH values obtained through the health fair. 794 of 858 health fair attendees participated. Most were women, and over 40% reported a family history of thyroid disease. We identified 97 (12.2%) participants with previously unknown thyroid dysfunction. No symptom or combination of symptoms discriminated between hypothyroid and euthyroid individuals. Hypothyroid and euthyroid participants in the health fair reported each symptom with a similar prevalence (p > 0.01), a prevalence which was very high. In fact, when compared with a previously published case-control study that reported symptoms, the euthyroid health fair participants reported a higher symptom prevalence (range 3.9% to 66.3%, mean 31.5%), than the euthyroid individuals from the case-control study (range 2% to 54%, mean 17.4%). A high proportion of previously undiagnosed thyroid disease was identified at this health fair. We initially hypothesized symptoms would distinguish between thyroid function states. However, this was not the case in this health fair screening population. The prevalence of reported symptoms was similar and high in both euthyroid and hypothyroid participants. Because attendees were self-selected, it is possible that this health fair that focused on thyroid disease attracted participants specifically concerned about thyroid health. Despite the lack of symptom discrimination, the much higher prevalence of hypothyroidism in this study

  8. Association Between Previous Meniscal Surgery and the Incidence of Chondral Lesions at Revision Anterior Cruciate Ligament Reconstruction

    Science.gov (United States)

    Brophy, Robert H.; Wright, Rick W.; David, Tal S.; McCormack, Robert G.; Sekiya, Jon K.; Svoboda, Steven J.; Huston, Laura J.; Haas, Amanda K.; Steger-May, Karen

    2013-01-01

    Background Knees undergoing revision anterior cruciate ligament (ACL) reconstruction typically have more intra-articular injuries than do knees undergoing primary reconstruction. Hypothesis Previous partial meniscectomy (PM) is associated with a higher rate of chondral lesions at revision ACL reconstruction, whereas previous meniscal repair (MR) is not associated with a higher rate of chondral lesions at revision ACL reconstruction, compared with knees undergoing revision ACL with no previous meniscal surgery. Study design Cohort study (Prevalence); Level of evidence, 2. Methods Data from a multicenter cohort was reviewed to determine the history of prior meniscal surgery (PM/MR) and the presence of grade II/III/IV chondral lesions at revision ACL reconstruction. The association between previous meniscal surgery and the incidence of chondral lesions was examined. Patient age was included as a covariate to determine if surgery type contributes predictive information independent of patient age. Results The cohort included 725 ACL revision surgeries. Chondrosis was associated with patient age (P meniscal surgery (P meniscal surgery (P meniscal surgery and knees with previous MR (P = .7). Previous partial meniscectomy was associated with a higher rate of chondrosis in the same compartment compared with knees without previous meniscal surgery (P meniscal surgery independent of the effect of patient age. Previous partial meniscectomy is associated with a higher incidence of articular cartilage lesions, whereas previous meniscal repair is not. Although this association may reflect underlying differences in the knee at the time of prior surgery, it does suggest that meniscal repair is preferable when possible at the time of ACL reconstruction. PMID:22374942

  9. Colistin Heteroresistance in Acinetobacter and Its Association with Previous Colistin Therapy▿

    OpenAIRE

    Hawley, Joshua S.; Murray, Clinton K.; Jorgensen, James H.

    2007-01-01

    Colistin heteroresistance has been reported among Acinetobacter isolates; however, its association with prior colistin therapy has not been not described. A population analysis profile identified resistant Acinetobacter subpopulations from colistin-susceptible clinical isolates. The proportion of cells exhibiting heteroresistance was significantly higher among isolates recovered from patients treated with colistin.

  10. Association of lipoprotein levels with mortality in subjects aged 50 + without previous diabetes or cardiovascular disease

    DEFF Research Database (Denmark)

    Bathum, Lise; Depont Christensen, René; Engers Pedersen, Lars

    2013-01-01

    This study aimed to investigate the association of lipoprotein and triglyceride levels with all-cause mortality in a population free from diabetes and cardiovascular disease (CVD) at baseline. The European Guidelines on cardiovascular disease prevention state that in general total cholesterol (TC...

  11. Implicit associative learning in synesthetes and nonsynesthetes.

    Science.gov (United States)

    Bankieris, Kaitlyn R; Aslin, Richard N

    2017-06-01

    Although cross-modal neural connections and genetic underpinnings are prominent in most current theories regarding the development of synesthesia, the potential role of associative learning in the formation of synesthetic associations has recently been revitalized. In this study, we investigated implicit associative learning in synesthetes and nonsynesthetes by recording reaction times to a target whose color was probabilistically correlated with its shape. A continuous measure of target detection at multiple time points during learning revealed that synesthetes and nonsynesthetes learn associations differently. Specifically, our results demonstrated a "fast-facilitation" learning effect for nonsynesthetes and a "fast-interference, slow-facilitation" learning effect for synesthetes. Additionally, synesthetes exhibited superior long-term memory for the learned associations in a surprise delayed retest. After this retest, participants implicitly learned new (shuffled) shape-color associations. We found that synesthetes experienced greater interference while learning these new shape-color associations. These results detail ways in which implicit associative learning and memory differ between synesthetes and nonsynesthetes.

  12. A previously unreported association between Nance-Horan syndrome and spontaneous dental abscesses.

    Science.gov (United States)

    Hibbert, Sally

    2005-02-01

    Atypical dentofacial structures may be the first indicator of other anomalies linked to a syndrome. This case describes the management of a 9-year-old girl referred for the routine management of supernumerary teeth. The anomalous form of her teeth, together with multiple supernumerary units and a history of congenital cataracts, were suggestive of a diagnosis of Nance-Horan syndrome. This is an X-linked disorder, in which females usually demonstrate mild expression; this case was unusual in respect to the marked phenotype expressed. Unusually, the girl developed 2 spontaneous abscesses of her noncarious upper incisor teeth; a feature never previously described in this syndrome. This report details the patient's dental management and discusses the possible pathogenesis of the dental abscesses, together with the genetic implications of this syndrome.

  13. Cochlear Implant Associated Labyrinthitis: A Previously Unrecognized Phenomenon With a Distinct Clinical and Electrophysiological Impedance Pattern.

    Science.gov (United States)

    Itayem, Deeyar A; Sladen, Douglas; Driscoll, Colin L; Neff, Brian A; Beatty, Charles W; Carlson, Matthew L

    2017-12-01

    To report a unique clinical entity "cochlear implant associated labyrinthitis," characterized by a distinct constellation of clinical symptoms and pattern of electrode impedance fluctuations. Retrospective chart review. All patients that underwent cochlear implantation between January 2014 and December 2016 were retrospectively reviewed. All subjects with acute onset dizziness, device performance decline, and characteristic erratic pattern of electrode impedances occurring after an asymptotic postoperative interval were identified and reported. Five patients with the above criteria were identified, representing 1.4% of all implant surgeries performed during this time. The median age at time of implantation was 71 years, and the median time interval between implantation and onset of symptoms was 126 days. All patients exhibited acute onset dizziness, subjective performance deterioration, erratic impedance pattern, and two experienced worsening tinnitus. Two of five patients underwent subsequent CT imaging, where good electrode placement was confirmed without cochlear ossification. Two of five patients received oral prednisone therapy. All patients reported a subjective improvement in symptoms and stabilization of electrode impedances. Three patients subsequently received vestibular testing, where significantly reduced peripheral vestibular function was identified. We describe a unique clinical entity, "cochlear implant associated labyrinthitis," characterized by a distinct constellation of clinical symptoms and corresponding electrode impedance anomalies. The exact cause for this event remains unknown, but may be related to viral illness, delayed foreign body reaction to the electrode, or a reaction to electrical stimulation. Future studies characterizing this unique clinical entity are needed to further elucidate cause and optimal management.

  14. Previously Undescribed Antibacterial Polyketides from Heterotrophic Bacillus amyloliquefaciens Associated with Seaweed Padina gymnospora.

    Science.gov (United States)

    Chakraborty, Kajal; Thilakan, Bini; Raola, Vamshi Krishna

    2018-02-01

    A heterotrophic marine bacterium Bacillus amyloliquefaciens isolated from seaweed Padina gymnospora exhibited broad spectra of antibacterial activities against pathogenic bacteria Aeromonas hydrophila, Vibrio harveyi, Vibrio vulnificus, and Vibrio parahaemolyticus. The seaweed-associated B. amyloliquefaciens was recognized to possess functional type I polyketide synthase-1 (pks-1) gene, and was used to isolate four homologous compounds with polyketide frameworks. The compounds were characterized as 11-(15-butyl-13-ethyl-tetrahydro-12-oxo-2H-pyran-13-yl) propyl-2-methylbenzoate (1), 9-(tetrahydro-12-isopropyl-11-oxofuran-10-yl)-ethyl-4-ethoxy-2-hydroxybenzoate (2), 12-(aminomethyl)-11-hydroxyhexanyl-10-phenylpropanoate (3), and 7-(14-hydroxypropan-13-yl)-8-isobutyl-7,8-dihydrobenzo[c]oxepin-1(3H)-one (4) by comprehensive nuclear magnetic resonance and mass spectroscopic experiments. The compounds 1-4 displayed significant antibacterial activities against clinically important pathogens V. parahaemolyticus and V. vulnificus (inhibitory zone diameter of ≥15 mm, 100 mcg on disk). The electronic and hydrophobic parameters appeared to hold a conspicuous part in directing the antibacterial properties of the compounds. This study revealed seaweed-associated B. amyloliquefaciens as potential source of antimicrobial polyketides for pharmaceutical applications.

  15. High prevalence of genetic variants previously associated with Brugada syndrome in new exome data

    DEFF Research Database (Denmark)

    Risgaard, B; Jabbari, R; Refsgaard, L

    2013-01-01

    to a surprisingly high genotype prevalence of 1:23 (274:6258). Genotyping the four common ESP-derived variants CACNA2D1 S709N, SCN5A F2004L, CACNB2 S143F, and CACNB2 T450I in the Danish controls, we found a genotype prevalence comparable with that found in ESP. We suggest that exome data are used in research......More than 300 variants in 12 genes have been associated with Brugada syndrome (BrS) which has a prevalence ranging between 1:2000 and 1:100,000. Until recently, there has been little knowledge regarding the distribution of genetic variations in the general population. This problem was partly solved...

  16. Association Between Previous Injury and Risk Factors for Future Injury in Preprofessional Ballet and Contemporary Dancers.

    Science.gov (United States)

    Kenny, Sarah J; Palacios-Derflingher, Luz; Shi, Qian; Whittaker, Jackie L; Emery, Carolyn A

    2017-10-20

    To determine the prevalence of self-reported 1-year injury history and examine its association with preparticipation evaluation components aimed at predicting future injury risk (PPE-IP) among preprofessional ballet and contemporary dancers. Cross-sectional study. Preprofessional ballet school, university contemporary dance program. Full-time preprofessional ballet and contemporary dancers. Preparticipation evaluation consisted of the Athletic Coping Skills Inventory-28, body mass index, total bone mineral density, ankle range of motion, active standing turnout, lumbopelvic control, unipedal dynamic balance, and Y-Balance test. Self-reported 1-year history of dance-related medical attention and/or time-loss injury. A total of 155 ballet [n = 90, 80 females, median age 15 years (range 11-19)] and contemporary [n = 65, 63 females, median age 20 years (range 17-30)] dancers participated. Forty-six percent (95% confidence interval (CI), 38.4-54.6) reported a 1-year injury history. Self-reported injury history was not associated with any PPE-IP, however, an influence of age and psychological coping skills on the relationship between 1-year injury history and PPE-IP was identified. Multivariable analyses revealed that prevalence of 1-year injury history did not differ by age [referent group 18 years: OR 0.69 (95% CI, 0.30-1.56)], or level of psychological coping skills [OR 1.35 (95% CI, 0.61-2.94)]. The prevalence of self-reported 1-year injury history among preprofessional ballet and contemporary dancers is high. Although measures of PPE-IP did not differ based on injury history, it is important that age and psychological coping skills are considered in future dance injury prevention and prediction research. Level 3 evidence.

  17. Seat belt associated central line fracture--a previously unreported complication in cystic fibrosis.

    Science.gov (United States)

    Ghayyda, Salim N S; Roland, Damian; Cade, Alan

    2008-09-01

    seatbelt worn to prevent injury in the sudden deceleration involved during a motor vehicle accident (MVA) has not been described previously in the CF literature We report the case of an 8 year old child who fractured her Vascuport(R) line secondary to seatbelt trauma following a road traffic accident (RTA). Children and adults with CF should be advised to sit in the car on the side that places the shoulder strap of the seatbelt on the opposite side to the TIVAD line.

  18. Two previously unknown Phytophthora species associated with brown rot of Pomelo (Citrus grandis fruits in Vietnam.

    Directory of Open Access Journals (Sweden)

    Ivana Puglisi

    Full Text Available Two distinct Phytophthora taxa were found to be associated with brown rot of pomelo (Citrus grandis, a new disease of this ancestral Citrus species, in the Vinh Long province, Mekong River Delta area, southern Vietnam. On the basis of morphological characters and using the ITS1-5.8S-ITS2 region of the rDNA and the cytochrome oxidase subunit 1 (COI as barcode genes, one of the two taxa was provisionally named as Phytophthora sp. prodigiosa, being closely related to but distinct from P. insolita, a species in Phytophthora Clade 9, while the other one, was closely related to but distinct from the Clade 2 species P. meadii and was informally designated as Phytophthora sp. mekongensis. Isolates of P. sp. prodigiosa and P. sp. mekongensis were also obtained from necrotic fibrous roots of Volkamer lemon (C. volkameriana rootstocks grafted with 'King' mandarin (Citrus nobilis and from trees of pomelo, respectively, in other provinces of the Mekong River Delta, indicating a widespread occurrence of both Phytophthora species in this citrus-growing area. Koch's postulates were fulfilled via pathogenicity tests on fruits of various Citrus species, including pomelo, grapefruit (Citrus x paradisi, sweet orange (Citrus x sinensis and bergamot (Citrus x bergamia as well as on the rootstock of 2-year-old trees of pomelo and sweet orange on 'Carrizo' citrange (C. sinensis 'Washington Navel' x Poncirus trifoliata. This is the first report of a Phytophthora species from Clade 2 other than P. citricola and P. citrophthora as causal agent of fruit brown rot of Citrus worldwide and the first report of P. insolita complex in Vietnam. Results indicate that likely Vietnam is still an unexplored reservoir of Phytophthora diversity.

  19. Two previously unknown Phytophthora species associated with brown rot of Pomelo (Citrus grandis) fruits in Vietnam.

    Science.gov (United States)

    Puglisi, Ivana; De Patrizio, Alessandro; Schena, Leonardo; Jung, Thomas; Evoli, Maria; Pane, Antonella; Van Hoa, Nguyen; Van Tri, Mai; Wright, Sandra; Ramstedt, Mauritz; Olsson, Christer; Faedda, Roberto; Magnano di San Lio, Gaetano; Cacciola, Santa Olga

    2017-01-01

    Two distinct Phytophthora taxa were found to be associated with brown rot of pomelo (Citrus grandis), a new disease of this ancestral Citrus species, in the Vinh Long province, Mekong River Delta area, southern Vietnam. On the basis of morphological characters and using the ITS1-5.8S-ITS2 region of the rDNA and the cytochrome oxidase subunit 1 (COI) as barcode genes, one of the two taxa was provisionally named as Phytophthora sp. prodigiosa, being closely related to but distinct from P. insolita, a species in Phytophthora Clade 9, while the other one, was closely related to but distinct from the Clade 2 species P. meadii and was informally designated as Phytophthora sp. mekongensis. Isolates of P. sp. prodigiosa and P. sp. mekongensis were also obtained from necrotic fibrous roots of Volkamer lemon (C. volkameriana) rootstocks grafted with 'King' mandarin (Citrus nobilis) and from trees of pomelo, respectively, in other provinces of the Mekong River Delta, indicating a widespread occurrence of both Phytophthora species in this citrus-growing area. Koch's postulates were fulfilled via pathogenicity tests on fruits of various Citrus species, including pomelo, grapefruit (Citrus x paradisi), sweet orange (Citrus x sinensis) and bergamot (Citrus x bergamia) as well as on the rootstock of 2-year-old trees of pomelo and sweet orange on 'Carrizo' citrange (C. sinensis 'Washington Navel' x Poncirus trifoliata). This is the first report of a Phytophthora species from Clade 2 other than P. citricola and P. citrophthora as causal agent of fruit brown rot of Citrus worldwide and the first report of P. insolita complex in Vietnam. Results indicate that likely Vietnam is still an unexplored reservoir of Phytophthora diversity.

  20. Learning rules for aversive associative memory formation.

    Science.gov (United States)

    Ozawa, Takaaki; Johansen, Joshua P

    2018-03-05

    For survival, organisms need the ability to flexibly modify their behavior. To achieve this, the brain is equipped with instructive brain circuits which trigger changes in neural connectivity and adaptive changes in behavior in response to environmental/internal challenges. Recent studies using a form of aversive associative learning termed fear conditioning have shed light on the neural mechanisms of instructive signaling. These studies demonstrate that fear learning is engaged through multiple, parallel aversive signaling pathways to the amygdala. Consistent with theoretical accounts of learning, activity in these circuits and behavioral learning is tightly regulated by the predictability of the aversive experience. However, in more complex learning conditions, these emotion circuits use a form of inference to approximate the appropriate reaction to danger. This suggests a revised view of how emotional learning systems represent aversive associations and how changes in these representations are instructed during learning. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Associations of obesity with newly diagnosed and previously known atopic diseases in Chinese adults: a case-control study

    OpenAIRE

    Xie, Biao; Wang, Zhiqiang; Wang, Yupeng; Liu, Meina; Wang, Yongchen

    2017-01-01

    To assess the associations of obesity with newly diagnosed and previously known atopic disorders in Chinese adults. 4,629 adults aged 18 years or older were recruited in Harbin, China. Among them, 1,114 were previously diagnosed atopic cases, 1,298 were newly diagnosed cases, and 2,217 non-atopic controls. Obesity and overweight are defined according to the criteria established by the Working Group on Obesity in China. The associations of obesity with known and newly diagnosed atopic disorder...

  2. Factors associated with successful self-directed learning using individualized learning plans during pediatric residency.

    Science.gov (United States)

    Li, Su-Ting T; Tancredi, Daniel J; Co, John Patrick T; West, Daniel C

    2010-01-01

    The aim of this study was to determine whether resident or program characteristics are associated with effective self-directed learning of residents. A cross-sectional survey of pediatric and medicine/pediatric residents and program directors from a nationally representative sample of residency programs was conducted. Self-directed learning efficacy was measured by resident-reported progress on learning goals from their most recent individualized learning plan (ILP). Multilevel linear regression models were used to analyze the relationship between learner and program characteristics and self-directed learning efficacy of residents. All program directors of participating programs (N = 46) completed the survey; the response rate from residents was 57% (992/1739). At the time of the survey, 78% of residents had previously written an ILP. Most residents achieved moderate self-directed learning efficacy. The most important factors associated with greater self-directed learning efficacy included using a system to track one's own progress in achieving learning goals, higher score on a propensity toward lifelong learning scale, and reporting greater confidence in self-directed learning abilities. Program characteristics, including program-level support for ILPs, had little or mixed association with resident self-directed learning efficacy. The most important factors associated with effective self-directed learning were resident characteristics. Our findings imply that residency programs should invest their limited resources in curricula that help residents develop measurable goals and systems for tracking progress toward goal attainment. Since propensity toward lifelong learning was an important factor, medical schools and residency training programs should enhance their efforts to develop this characteristic in learners. Copyright 2010 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

  3. No trade-off between learning speed and associative flexibility in bumblebees: a reversal learning test with multiple colonies.

    Directory of Open Access Journals (Sweden)

    Nigel E Raine

    Full Text Available Potential trade-offs between learning speed and memory-related performance could be important factors in the evolution of learning. Here, we test whether rapid learning interferes with the acquisition of new information using a reversal learning paradigm. Bumblebees (Bombus terrestris were trained to associate yellow with a floral reward. Subsequently the association between colour and reward was reversed, meaning bees then had to learn to visit blue flowers. We demonstrate that individuals that were fast to learn yellow as a predictor of reward were also quick to reverse this association. Furthermore, overnight memory retention tests suggest that faster learning individuals are also better at retaining previously learned information. There is also an effect of relatedness: colonies whose workers were fast to learn the association between yellow and reward also reversed this association rapidly. These results are inconsistent with a trade-off between learning speed and the reversal of a previously made association. On the contrary, they suggest that differences in learning performance and cognitive (behavioural flexibility could reflect more general differences in colony learning ability. Hence, this study provides additional evidence to support the idea that rapid learning and behavioural flexibility have adaptive value.

  4. New population-based exome data are questioning the pathogenicity of previously cardiomyopathy-associated genetic variants

    DEFF Research Database (Denmark)

    Andreasen, Charlotte Hartig; Nielsen, Jonas B; Refsgaard, Lena

    2013-01-01

    variants in the NHLBI-Go Exome Sequencing Project (ESP) containing exome data from 6500 individuals. In ESP, we identified 94 variants out of 687 (14%) variants previously associated with HCM, 58 out of 337 (17%) variants associated with DCM, and 38 variants out of 209 (18%) associated with ARVC...... with these cardiomyopathies, but the disease-causing effect of reported variants is often dubious. In order to identify possible false-positive variants, we investigated the prevalence of previously reported cardiomyopathy-associated variants in recently published exome data. We searched for reported missense and nonsense...... times higher than expected from the phenotype prevalences in the general population (HCM 1:500, DCM 1:2500, and ARVC 1:5000) and our data suggest that a high number of these variants are not monogenic causes of cardiomyopathy....

  5. Knee Osteoarthritis Is Associated With Previous Meniscus and Anterior Cruciate Ligament Surgery Among Elite College American Football Athletes

    Science.gov (United States)

    Smith, Matthew V.; Nepple, Jeffrey J.; Wright, Rick W.; Matava, Matthew J.; Brophy, Robert H.

    2016-01-01

    Background: Football puts athletes at risk for knee injuries such meniscus and anterior cruciate ligament (ACL) tears, which are associated with the development of osteoarthritis (OA). Previous knee surgery, player position, and body mass index (BMI) may be associated with knee OA. Hypothesis: In elite football players undergoing knee magnetic resonance imaging at the National Football League’s Invitational Combine, the prevalence of knee OA is associated with previous knee surgery and BMI. Study Design: Retrospective cohort. Level of Evidence: Level 4. Methods: A retrospective review was performed of all participants of the National Football League Combine from 2005 to 2009 who underwent magnetic resonance imaging of the knee because of prior knee injury, surgery, or knee-related symptoms or concerning examination findings. Imaging studies were reviewed for evidence of OA. History of previous knee surgery—including ACL reconstruction, meniscal procedures, and articular cartilage surgery—and position were recorded for each athlete. BMI was calculated based on height and weight. Results: There was a higher prevalence of OA in knees with a history of previous knee surgery (23% vs 4.0%, P 30 kg/m2 was also associated with a higher risk of OA (P = 0.007) but player position was not associated with knee OA. Conclusions: Previous knee surgery, particularly ACL reconstruction and partial meniscectomy, and elevated BMI are associated with knee OA in elite football players. Future research should investigate ways to minimize the risk of OA after knee surgery in these athletes. Clinical Relevance: Treatment of knee injuries in football athletes should consider chondroprotection, including meniscal preservation and cartilage repair, when possible. PMID:27940573

  6. Knee Osteoarthritis Is Associated With Previous Meniscus and Anterior Cruciate Ligament Surgery Among Elite College American Football Athletes.

    Science.gov (United States)

    Smith, Matthew V; Nepple, Jeffrey J; Wright, Rick W; Matava, Matthew J; Brophy, Robert H

    Football puts athletes at risk for knee injuries such meniscus and anterior cruciate ligament (ACL) tears, which are associated with the development of osteoarthritis (OA). Previous knee surgery, player position, and body mass index (BMI) may be associated with knee OA. In elite football players undergoing knee magnetic resonance imaging at the National Football League's Invitational Combine, the prevalence of knee OA is associated with previous knee surgery and BMI. Retrospective cohort. Level 4. A retrospective review was performed of all participants of the National Football League Combine from 2005 to 2009 who underwent magnetic resonance imaging of the knee because of prior knee injury, surgery, or knee-related symptoms or concerning examination findings. Imaging studies were reviewed for evidence of OA. History of previous knee surgery-including ACL reconstruction, meniscal procedures, and articular cartilage surgery-and position were recorded for each athlete. BMI was calculated based on height and weight. There was a higher prevalence of OA in knees with a history of previous knee surgery (23% vs 4.0%, P 30 kg/m 2 was also associated with a higher risk of OA ( P = 0.007) but player position was not associated with knee OA. Previous knee surgery, particularly ACL reconstruction and partial meniscectomy, and elevated BMI are associated with knee OA in elite football players. Future research should investigate ways to minimize the risk of OA after knee surgery in these athletes. Treatment of knee injuries in football athletes should consider chondroprotection, including meniscal preservation and cartilage repair, when possible.

  7. Associations of obesity with newly diagnosed and previously known atopic diseases in Chinese adults: a case-control study.

    Science.gov (United States)

    Xie, Biao; Wang, Zhiqiang; Wang, Yupeng; Liu, Meina; Wang, Yongchen

    2017-03-02

    To assess the associations of obesity with newly diagnosed and previously known atopic disorders in Chinese adults. 4,629 adults aged 18 years or older were recruited in Harbin, China. Among them, 1,114 were previously diagnosed atopic cases, 1,298 were newly diagnosed cases, and 2,217 non-atopic controls. Obesity and overweight are defined according to the criteria established by the Working Group on Obesity in China. The associations of obesity with known and newly diagnosed atopic disorders were assessed using logistic regressions. Obesity was significantly associated with known atopic disorders (adjusted OR = 2.41 (95% CI: 1.81, 3.22)). The association of obesity with newly diagnosed atopic cases was not as strong as that with known cases, and was not statistically significant (adjusted OR = 1.27 (95% CI: 0.94, 1.72)). The similar pattern was observed in different allergic diseases, gender and age stratifications. The association between overweight and atopic diseases were not significant. Obesity is strongly associated with previously diagnosed atopic cases but not so with newly diagnosed atopic cases in Chinese adults. It is likely that people with atopic disorders have a higher risk of developing obesity. Our findings are important for the management of atopic disorders and chronic disease prevention among atopic disease patients.

  8. New population-based exome data question the pathogenicity of some genetic variants previously associated with Marfan syndrome

    DEFF Research Database (Denmark)

    Yang, Ren-Qiang; Jabbari, Javad; Cheng, Xiao-Shu

    2014-01-01

    BACKGROUND: Marfan syndrome (MFS) is a rare autosomal dominantly inherited connective tissue disorder with an estimated prevalence of 1:5,000. More than 1000 variants have been previously reported to be associated with MFS. However, the disease-causing effect of these variants may be questionable...

  9. Analysis of over 10,000 Cases finds no association between previously reported candidate polymorphisms and ovarian cancer outcome

    DEFF Research Database (Denmark)

    White, Kristin L; Vierkant, Robert A; Fogarty, Zachary C

    2013-01-01

    Ovarian cancer is a leading cause of cancer-related death among women. In an effort to understand contributors to disease outcome, we evaluated single-nucleotide polymorphisms (SNP) previously associated with ovarian cancer recurrence or survival, specifically in angiogenesis, inflammation, mitosis...

  10. Animal social learning: associations and adaptations.

    Science.gov (United States)

    Reader, Simon M

    2016-01-01

    Social learning, learning from others, is a powerful process known to impact the success and survival of humans and non-human animals alike. Yet we understand little about the neurocognitive and other processes that underpin social learning. Social learning has often been assumed to involve specialized, derived cognitive processes that evolve and develop independently from other processes. However, this assumption is increasingly questioned, and evidence from a variety of organisms demonstrates that current, recent, and early life experience all predict the reliance on social information and thus can potentially explain variation in social learning as a result of experiential effects rather than evolved differences. General associative learning processes, rather than adaptive specializations, may underpin much social learning, as well as social learning strategies. Uncovering these distinctions is important to a variety of fields, for example by widening current views of the possible breadth and adaptive flexibility of social learning. Nonetheless, just like adaptationist evolutionary explanations, associationist explanations for social learning cannot be assumed, and empirical work is required to uncover the mechanisms involved and their impact on the efficacy of social learning. This work is being done, but more is needed. Current evidence suggests that much social learning may be based on 'ordinary' processes but with extraordinary consequences.

  11. Prefrontal Dopamine in Associative Learning and Memory

    Science.gov (United States)

    Puig, M. Victoria; Antzoulatos, Evan G.; Miller, Earl K.

    2014-01-01

    Learning to associate specific objects or actions with rewards and remembering the associations are everyday tasks crucial for our flexible adaptation to the environment. These higher-order cognitive processes depend on the prefrontal cortex (PFC) and frontostriatal circuits that connect areas in the frontal lobe with the striatum in the basal ganglia. Both structures are densely innervated by dopamine (DA) afferents that originate in the midbrain. Although the activity of DA neurons is thought to be important for learning, the exact role of DA transmission in frontostriatal circuits during learning-related tasks is still unresolved. Moreover, the neural substrates of this modulation are poorly understood. Here, we review our recent work in monkeys utilizing local pharmacology of DA agents in the PFC to investigate the cellular mechanisms of DA modulation of associative learning and memory. We show that blocking both D1 and D2 receptors in the lateral PFC impairs learning of new stimulus-response associations and cognitive flexibility, but not the memory of highly familiar associations. In addition, D2 receptors may also contribute to motivation. The learning deficits correlated with reductions of neural information about the associations in PFC neurons, alterations in global excitability and spike synchronization, and exaggerated alpha and beta neural oscillations. Our findings provide new insights into how DA transmission modulate associative learning and memory processes in frontostriatal systems. PMID:25241063

  12. Analysis of Over 10,000 Cases Finds No Association between Previously-Reported Candidate Polymorphisms and Ovarian Cancer Outcome

    Science.gov (United States)

    White, Kristin L.; Vierkant, Robert A.; Fogarty, Zachary C.; Charbonneau, Bridget; Block, Matthew S.; Pharoah, Paul D.P.; Chenevix-Trench, Georgia; Rossing, Mary Anne; Cramer, Daniel W.; Pearce, C. Leigh; Schildkraut, Joellen M.; Menon, Usha; Kjaer, Susanne Kruger; Levine, Douglas A.; Gronwald, Jacek; Culver, Hoda Anton; Whittemore, Alice S.; Karlan, Beth Y.; Lambrechts, Diether; Wentzensen, Nicolas; Kupryjanczyk, Jolanta; Chang-Claude, Jenny; Bandera, Elisa V.; Hogdall, Estrid; Heitz, Florian; Kaye, Stanley B.; Fasching, Peter A.; Campbell, Ian; Goodman, Marc T.; Pejovic, Tanja; Bean, Yukie; Lurie, Galina; Eccles, Diana; Hein, Alexander; Beckmann, Matthias W.; Ekici, Arif B.; Paul, James; Brown, Robert; Flanagan, James; Harter, Philipp; du Bois, Andreas; Schwaab, Ira; Hogdall, Claus K.; Lundvall, Lene; Olson, Sara H.; Orlow, Irene; Paddock, Lisa E.; Rudolph, Anja; Eilber, Ursula; Dansonka-Mieszkowska, Agnieszka; Rzepecka, Iwona K.; Ziolkowska-Seta, Izabela; Brinton, Louise; Yang, Hannah; Garcia-Closas, Montserrat; Despierre, Evelyn; Lambrechts, Sandrina; Vergote, Ignace; Walsh, Christine; Lester, Jenny; Sieh, Weiva; McGuire, Valerie; Rothstein, Joseph H.; Ziogas, Argyrios; Lubiński, Jan; Cybulski, Cezary; Menkiszak, Janusz; Jensen, Allan; Gayther, Simon A.; Ramus, Susan J.; Gentry-Maharaj, Aleksandra; Berchuck, Andrew; Wu, Anna H.; Pike, Malcolm C.; Van Den Berg, David; Terry, Kathryn L.; Vitonis, Allison F.; Doherty, Jennifer A.; Johnatty, Sharon; deFazio, Anna; Song, Honglin; Tyrer, Jonathan; Sellers, Thomas A.; Phelan, Catherine M.; Kalli, Kimberly R.; Cunningham, Julie M.; Fridley, Brooke L.; Goode, Ellen L.

    2013-01-01

    Background Ovarian cancer is a leading cause of cancer-related death among women. In an effort to understand contributors to disease outcome, we evaluated single-nucleotide polymorphisms (SNPs) previously associated with ovarian cancer recurrence or survival, specifically in angiogenesis, inflammation, mitosis, and drug disposition genes. Methods Twenty-seven SNPs in VHL, HGF, IL18, PRKACB, ABCB1, CYP2C8, ERCC2, and ERCC1 previously associated with ovarian cancer outcome were genotyped in 10,084 invasive cases from 28 studies from the Ovarian Cancer Association Consortium with over 37,000 observed person-years and 4,478 deaths. Cox proportional hazards models were used to examine the association between candidate SNPs and ovarian cancer recurrence or survival with and without adjustment for key covariates. Results We observed no association between genotype and ovarian cancer recurrence or survival for any of the SNPs examined. Conclusions These results refute prior associations between these SNPs and ovarian cancer outcome and underscore the importance of maximally powered genetic association studies. Impact These variants should not be used in prognostic models. Alternate approaches to uncovering inherited prognostic factors, if they exist, are needed. PMID:23513043

  13. Analysis of over 10,000 Cases finds no association between previously reported candidate polymorphisms and ovarian cancer outcome.

    Science.gov (United States)

    White, Kristin L; Vierkant, Robert A; Fogarty, Zachary C; Charbonneau, Bridget; Block, Matthew S; Pharoah, Paul D P; Chenevix-Trench, Georgia; Rossing, Mary Anne; Cramer, Daniel W; Pearce, Celeste Leigh; Schildkraut, Joellen M; Menon, Usha; Kjaer, Susanne Kruger; Levine, Douglas A; Gronwald, Jacek; Culver, Hoda Anton; Whittemore, Alice S; Karlan, Beth Y; Lambrechts, Diether; Wentzensen, Nicolas; Kupryjanczyk, Jolanta; Chang-Claude, Jenny; Bandera, Elisa V; Hogdall, Estrid; Heitz, Florian; Kaye, Stanley B; Fasching, Peter A; Campbell, Ian; Goodman, Marc T; Pejovic, Tanja; Bean, Yukie; Lurie, Galina; Eccles, Diana; Hein, Alexander; Beckmann, Matthias W; Ekici, Arif B; Paul, James; Brown, Robert; Flanagan, James M; Harter, Philipp; du Bois, Andreas; Schwaab, Ira; Hogdall, Claus K; Lundvall, Lene; Olson, Sara H; Orlow, Irene; Paddock, Lisa E; Rudolph, Anja; Eilber, Ursula; Dansonka-Mieszkowska, Agnieszka; Rzepecka, Iwona K; Ziolkowska-Seta, Izabela; Brinton, Louise; Yang, Hannah; Garcia-Closas, Montserrat; Despierre, Evelyn; Lambrechts, Sandrina; Vergote, Ignace; Walsh, Christine; Lester, Jenny; Sieh, Weiva; McGuire, Valerie; Rothstein, Joseph H; Ziogas, Argyrios; Lubinski, Jan; Cybulski, Cezary; Menkiszak, Janusz; Jensen, Allan; Gayther, Simon A; Ramus, Susan J; Gentry-Maharaj, Aleksandra; Berchuck, Andrew; Wu, Anna H; Pike, Malcolm C; Van Denberg, David; Terry, Kathryn L; Vitonis, Allison F; Doherty, Jennifer A; Johnatty, Sharon E; Defazio, Anna; Song, Honglin; Tyrer, Jonathan; Sellers, Thomas A; Phelan, Catherine M; Kalli, Kimberly R; Cunningham, Julie M; Fridley, Brooke L; Goode, Ellen L

    2013-05-01

    Ovarian cancer is a leading cause of cancer-related death among women. In an effort to understand contributors to disease outcome, we evaluated single-nucleotide polymorphisms (SNP) previously associated with ovarian cancer recurrence or survival, specifically in angiogenesis, inflammation, mitosis, and drug disposition genes. Twenty-seven SNPs in VHL, HGF, IL18, PRKACB, ABCB1, CYP2C8, ERCC2, and ERCC1 previously associated with ovarian cancer outcome were genotyped in 10,084 invasive cases from 28 studies from the Ovarian Cancer Association Consortium with over 37,000-observed person-years and 4,478 deaths. Cox proportional hazards models were used to examine the association between candidate SNPs and ovarian cancer recurrence or survival with and without adjustment for key covariates. We observed no association between genotype and ovarian cancer recurrence or survival for any of the SNPs examined. These results refute prior associations between these SNPs and ovarian cancer outcome and underscore the importance of maximally powered genetic association studies. These variants should not be used in prognostic models. Alternate approaches to uncovering inherited prognostic factors, if they exist, are needed.

  14. Changes in association between previous therapeutic abortion and preterm birth in Scotland, 1980 to 2008: a historical cohort study.

    Directory of Open Access Journals (Sweden)

    Clare Oliver-Williams

    Full Text Available Numerous studies have demonstrated that therapeutic termination of pregnancy (abortion is associated with an increased risk of subsequent preterm birth. However, the literature is inconsistent, and methods of abortion have changed dramatically over the last 30 years. We hypothesized that the association between previous abortion and the risk of preterm first birth changed in Scotland between 1 January 1980 and 31 December 2008.We studied linked Scottish national databases of births and perinatal deaths. We analysed the risk of preterm birth in relation to the number of previous abortions in 732,719 first births (≥24 wk, adjusting for maternal characteristics. The risk (adjusted odds ratio [95% CI] of preterm birth was modelled using logistic regression, and associations were expressed for a one-unit increase in the number of previous abortions. Previous abortion was associated with an increased risk of preterm birth (1.12 [1.09-1.16]. When analysed by year of delivery, the association was strongest in 1980-1983 (1.32 [1.21-1.43], progressively declined between 1984 and 1999, and was no longer apparent in 2000-2003 (0.98 [0.91-1.05] or 2004-2008 (1.02 [0.95-1.09]. A statistical test for interaction between previous abortion and year was highly statistically significant (p<0.001. Analysis of data for abortions among nulliparous women in Scotland 1992-2008 demonstrated that the proportion that were surgical without use of cervical pre-treatment decreased from 31% to 0.4%, and that the proportion of medical abortions increased from 18% to 68%.Previous abortion was a risk factor for spontaneous preterm birth in Scotland in the 1980s and 1990s, but the association progressively weakened and disappeared altogether by 2000. These changes were paralleled by increasing use of medical abortion and cervical pre-treatment prior to surgical abortion. Although it is plausible that the two trends were related, we could not test this directly as the data on

  15. Associative learning for a robot intelligence

    CERN Document Server

    Andreae, John H

    1998-01-01

    The explanation of brain functioning in terms of the association of ideas has been popular since the 17th century. Recently, however, the process of association has been dismissed as computationally inadequate by prominent cognitive scientists. In this book, a sharper definition of the term "association" is used to revive the process by showing that associative learning can indeed be computationally powerful. Within an appropriate organization, associative learning can be embodied in a robot to realize a human-like intelligence, which sets its own goals, exhibits unique unformalizable behaviou

  16. The association between previous and future severe exacerbations of chronic obstructive pulmonary disease: Updating the literature using robust statistical methodology.

    Science.gov (United States)

    Sadatsafavi, Mohsen; Xie, Hui; Etminan, Mahyar; Johnson, Kate; FitzGerald, J Mark

    2018-01-01

    There is minimal evidence on the extent to which the occurrence of a severe acute exacerbation of COPD that results in hospitalization affects the subsequent disease course. Previous studies on this topic did not generate causally-interpretable estimates. Our aim was to use corrected methodology to update previously reported estimates of the associations between previous and future exacerbations in these patients. Using administrative health data in British Columbia, Canada (1997-2012), we constructed a cohort of patients with at least one severe exacerbation, defined as an episode of inpatient care with the main diagnosis of COPD based on international classification of diseases (ICD) codes. We applied a random-effects 'joint frailty' survival model that is particularly developed for the analysis of recurrent events in the presence of competing risk of death and heterogeneity among individuals in their rate of events. Previous severe exacerbations entered the model as dummy-coded time-dependent covariates, and the model was adjusted for several observable patient and disease characteristics. 35,994 individuals (mean age at baseline 73.7, 49.8% female, average follow-up 3.21 years) contributed 34,271 severe exacerbations during follow-up. The first event was associated with a hazard ratio (HR) of 1.75 (95%CI 1.69-1.82) for the risk of future severe exacerbations. This risk decreased to HR = 1.36 (95%CI 1.30-1.42) for the second event and to 1.18 (95%CI 1.12-1.25) for the third event. The first two severe exacerbations that occurred during follow-up were also significantly associated with increased risk of all-cause mortality. There was substantial heterogeneity in the individual-specific rate of severe exacerbations. Even after adjusting for observable characteristics, individuals in the 97.5th percentile of exacerbation rate had 5.6 times higher rate of severe exacerbations than those in the 2.5th percentile. Using robust statistical methodology that controlled

  17. The association between subjective memory complaint and objective cognitive function in older people with previous major depression.

    Directory of Open Access Journals (Sweden)

    Chung-Shiang Chu

    Full Text Available The goal of this study is to investigate associations between subjective memory complaint and objective cognitive performance in older people with previous major depression-a high-risk sample for cognitive impairment and later dementia. A cross-sectional study was carried out in people aged 60 or over with previous major depression but not fulfilling current major depression criteria according to DSM-IV-TR. People with dementia or Mini-Mental State Examination score less than 17 were excluded. Subjective memory complaint was defined on the basis of a score ≧4 on the subscale of Geriatric Mental State schedule, a maximum score of 8. Older people aged equal or over 60 without any psychiatric diagnosis were enrolled as healthy controls. Cognitive function was evaluated using a series of cognitive tests assessing verbal memory, attention/speed, visuospatial function, verbal fluency, and cognitive flexibility in all participants. One hundred and thirteen older people with previous major depression and forty-six healthy controls were enrolled. Subjective memory complaint was present in more than half of the participants with depression history (55.8%. Among those with major depression history, subjective memory complaint was associated with lower total immediate recall and delayed verbal recall scores after adjustment. The associations between subjective memory complaint and worse memory performance were stronger in participants with lower depressive symptoms (Hamilton Depression Rating Scale score<7. The results suggest subjective memory complaint may be a valid appraisal of memory performance in older people with previous major depression and consideration should be given to more proactive assessment and follow-up in these clinical samples.

  18. Individual-level factors associated with variation in mycobacterial-specific immune response: Gender and previous BCG vaccination status.

    Science.gov (United States)

    Rhodes, Sophie J; Knight, Gwenan M; Fielding, Katherine; Scriba, Thomas J; Pathan, Ansar A; McShane, Helen; Fletcher, Helen; White, Richard G

    2016-01-01

    A more effective tuberculosis (TB) vaccine is needed to eliminate TB disease. Many new vaccine candidates enhance the immunogenicity of the existing vaccine, Bacillus Calmette-Guérin (BCG). Understanding BCG induced immune variation is key to developing a new vaccine. We aimed to establish if individual-level covariates were associated with cell-mediated immune response (interferon gamma (IFN-γ)) at vaccine trial enrolment (baseline) in a long-term retrospective analysis (LTR) and after BCG vaccination in a short-term prospective analysis (STP). Four covariates were analysed: gender, country, BCG vaccination history and monocyte/lymphocyte cell count ratio. Univariable and multivariable linear regression were conducted on IFN-γ response at baseline for LTR, and area under the curve (AUC), 24 week and peak IFN-γ response for STP. Previous BCG vaccination was strongly associated with higher IFN-γ response at baseline (LTR analysis) (p-values response (p-value = 0.1). BCG revaccination was strongly associated with a larger response increase than primary-vaccination (AUC & peak p-values 0.1). This analysis suggests that previous BCG vaccination and gender are associated with durable IFN-γ responses. Vaccine trials may need to stratify by BCG vaccination history and gender. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Visual attention to features by associative learning.

    Science.gov (United States)

    Gozli, Davood G; Moskowitz, Joshua B; Pratt, Jay

    2014-11-01

    Expecting a particular stimulus can facilitate processing of that stimulus over others, but what is the fate of other stimuli that are known to co-occur with the expected stimulus? This study examined the impact of learned association on feature-based attention. The findings show that the effectiveness of an uninformative color transient in orienting attention can change by learned associations between colors and the expected target shape. In an initial acquisition phase, participants learned two distinct sequences of stimulus-response-outcome, where stimuli were defined by shape ('S' vs. 'H'), responses were localized key-presses (left vs. right), and outcomes were colors (red vs. green). Next, in a test phase, while expecting a target shape (80% probable), participants showed reliable attentional orienting to the color transient associated with the target shape, and showed no attentional orienting with the color associated with the alternative target shape. This bias seemed to be driven by learned association between shapes and colors, and not modulated by the response. In addition, the bias seemed to depend on observing target-color conjunctions, since encountering the two features disjunctively (without spatiotemporal overlap) did not replicate the findings. We conclude that associative learning - likely mediated by mechanisms underlying visual object representation - can extend the impact of goal-driven attention to features associated with a target stimulus. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Critical evidence for the prediction error theory in associative learning.

    Science.gov (United States)

    Terao, Kanta; Matsumoto, Yukihisa; Mizunami, Makoto

    2015-03-10

    In associative learning in mammals, it is widely accepted that the discrepancy, or error, between actual and predicted reward determines whether learning occurs. Complete evidence for the prediction error theory, however, has not been obtained in any learning systems: Prediction error theory stems from the finding of a blocking phenomenon, but blocking can also be accounted for by other theories, such as the attentional theory. We demonstrated blocking in classical conditioning in crickets and obtained evidence to reject the attentional theory. To obtain further evidence supporting the prediction error theory and rejecting alternative theories, we constructed a neural model to match the prediction error theory, by modifying our previous model of learning in crickets, and we tested a prediction from the model: the model predicts that pharmacological intervention of octopaminergic transmission during appetitive conditioning impairs learning but not formation of reward prediction itself, and it thus predicts no learning in subsequent training. We observed such an "auto-blocking", which could be accounted for by the prediction error theory but not by other competitive theories to account for blocking. This study unambiguously demonstrates validity of the prediction error theory in associative learning.

  1. Previously Unidentified Single Nucleotide Polymorphisms in HIV/AIDS Cases Associate with Clinical Parameters and Disease Progression

    Directory of Open Access Journals (Sweden)

    Vladimir V. Anokhin

    2016-01-01

    Full Text Available The genetic background of an individual plays an important role in the progression of HIV infection to AIDS. Identifying previously unknown or uncharacterized single nucleotide polymorphisms (SNPs that associate with disease progression may reveal important therapeutic targets and provide a greater understanding of disease pathogenesis. In the present study, we employed ultra-high multiplex PCR on an Ion Torrent next-generation sequencing platform to sequence 23 innate immune genes from 94 individuals with HIV/AIDS. This data was used to identify potential associations of SNPs with clinical parameters and disease progression. SNPs that associated with an increased viral load were identified in the genes for the interleukin 15 receptor (IL15RA, toll-like receptor 7 (TLR7, tripartite motif-containing protein 5 (TRIM5, and two killer-cell immunoglobulin-like receptors (KIR2DL1 and KIR2DL3. Additionally, SNPs that associated with progression from HIV infection to AIDS were identified in two 2′-5′-oligoadenylate synthetase genes (OAS2 and OAS3. In contrast, other SNPs identified in OAS2 and OAS3 genes, as well as in the TRIM5 and KIR2DS4 genes, were associated with a slower progression of disease. Taken together, our data demonstrates the utility of ultra-high multiplex PCR in identifying polymorphisms of potential clinical significance and further,identifies SNPs that may play a role in HIV pathogenesis.

  2. Current suicidality and previous suicidal attempts in patients with schizophrenia are associated with different dimensions of temperament and character.

    Science.gov (United States)

    Aukst Margetić, Branka; Jakovljević, Miro; Ivanec, Dragutin; Marčinko, Darko; Margetić, Branimir; Jakšić, Nenad

    2012-12-30

    Suicide is a major public health problem and the leading cause of premature death in patients with schizophrenia. Information about the patient's personality is helpful for assessing the risk of suicide attempts and suicidal ideation. The sample consisted of 120 outpatients with a diagnosis of schizophrenia, 29 of whom had previously attempted suicide. We used the Temperament and Character Inventory to assess personality differences between patients who had previously attempted and had not previously attempted suicide and between patients who had and did not have current suicidal ideation. Current suicidal ideation was assessed using the four-point severity scale, which is item nine from the Beck Depression Inventory. The character dimension Self-transcendence was shown by logistic regression to be a predictor of lifetime suicide attempts. Low Self-directedness was shown to be a predictor of current suicidal ideation. To prevent suicidal behaviour, it is important to better understand the personality traits associated with suicidal ideation and suicide attempts. Suicide attempts and suicidal ideation in schizophrenia may not represent the same phenomenon ranging on a single continuum. The importance of these results suggests that further study is needed. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. Grounding cognitive control in associative learning.

    Science.gov (United States)

    Abrahamse, Elger; Braem, Senne; Notebaert, Wim; Verguts, Tom

    2016-07-01

    Cognitive control covers a broad range of cognitive functions, but its research and theories typically remain tied to a single domain. Here we outline and review an associative learning perspective on cognitive control in which control emerges from associative networks containing perceptual, motor, and goal representations. Our review identifies 3 trending research themes that are shared between the domains of conflict adaptation, task switching, response inhibition, and attentional control: Cognitive control is context-specific, can operate in the absence of awareness, and is modulated by reward. As these research themes can be envisaged as key characteristics of learning, we propose that their joint emergence across domains is not coincidental but rather reflects a (latent) growth of interest in learning-based control. Associative learning has the potential for providing broad-scaled integration to cognitive control theory, and offers a promising avenue for understanding cognitive control as a self-regulating system without postulating an ill-defined set of homunculi. We discuss novel predictions, theoretical implications, and immediate challenges that accompany an associative learning perspective on cognitive control. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  4. Evolution of associative learning in chemical networks.

    Directory of Open Access Journals (Sweden)

    Simon McGregor

    Full Text Available Organisms that can learn about their environment and modify their behaviour appropriately during their lifetime are more likely to survive and reproduce than organisms that do not. While associative learning - the ability to detect correlated features of the environment - has been studied extensively in nervous systems, where the underlying mechanisms are reasonably well understood, mechanisms within single cells that could allow associative learning have received little attention. Here, using in silico evolution of chemical networks, we show that there exists a diversity of remarkably simple and plausible chemical solutions to the associative learning problem, the simplest of which uses only one core chemical reaction. We then asked to what extent a linear combination of chemical concentrations in the network could approximate the ideal Bayesian posterior of an environment given the stimulus history so far? This Bayesian analysis revealed the 'memory traces' of the chemical network. The implication of this paper is that there is little reason to believe that a lack of suitable phenotypic variation would prevent associative learning from evolving in cell signalling, metabolic, gene regulatory, or a mixture of these networks in cells.

  5. Word learning emerges from the interaction of online referent selection and slow associative learning

    Science.gov (United States)

    McMurray, Bob; Horst, Jessica S.; Samuelson, Larissa K.

    2013-01-01

    Classic approaches to word learning emphasize the problem of referential ambiguity: in any naming situation the referent of a novel word must be selected from many possible objects, properties, actions, etc. To solve this problem, researchers have posited numerous constraints, and inference strategies, but assume that determining the referent of a novel word is isomorphic to learning. We present an alternative model in which referent selection is an online process that is independent of long-term learning. This two timescale approach creates significant power in the developing system. We illustrate this with a dynamic associative model in which referent selection is simulated as dynamic competition between competing referents, and learning is simulated using associative (Hebbian) learning. This model can account for a range of findings including the delay in expressive vocabulary relative to receptive vocabulary, learning under high degrees of referential ambiguity using cross-situational statistics, accelerating (vocabulary explosion) and decelerating (power-law) learning rates, fast-mapping by mutual exclusivity (and differences in bilinguals), improvements in familiar word recognition with development, and correlations between individual differences in speed of processing and learning. Five theoretical points are illustrated. 1) Word learning does not require specialized processes – general association learning buttressed by dynamic competition can account for much of the literature. 2) The processes of recognizing familiar words are not different than those that support novel words (e.g., fast-mapping). 3) Online competition may allow the network (or child) to leverage information available in the task to augment performance or behavior despite what might be relatively slow learning or poor representations. 4) Even associative learning is more complex than previously thought – a major contributor to performance is the pruning of incorrect associations

  6. Association of Previous Clinical Breast Examination With Reduced Delays and Earlier-Stage Breast Cancer Diagnosis Among Women in Peru.

    Science.gov (United States)

    Romanoff, Anya; Constant, Tara Hayes; Johnson, Kay M; Guadiamos, Manuel Cedano; Vega, Ana María Burga; Zunt, Joseph; Anderson, Benjamin O

    2017-11-01

    Mammographic screening is impractical in most of the world where breast cancers are first identified based on clinical signs and symptoms. Clinical breast examination may improve early diagnosis directly by finding breast cancers at earlier stages or indirectly by heightening women's awareness of breast health concerns. To investigate factors that influence time to presentation and stage at diagnosis among patients with breast cancer to determine whether history of previous clinical breast examination is associated with earlier presentation and/or earlier cancer stage at diagnosis. In this cross-sectional analysis of individual patient interviews using a validated Breast Cancer Delay Questionnaire, 113 (71.1%) of 159 women with breast cancer treated at a federally funded tertiary care referral cancer center in Trujillo, Peru, from February 1 through May 31, 2015, were studied. Method of breast cancer detection and factors that influence time to and stage at diagnosis. Of 113 women with diagnosed cancer (mean [SD] age, 54 [10.8] years; age range, 32-82 years), 105 (92.9%) had self-detected disease. Of the 93 women for whom stage was documented, 45 (48.4%) were diagnosed with early-stage disease (American Joint Committee on Cancer [AJCC] stage 0, I, or II), and 48 (51.6%) were diagnosed with late-stage disease (AJCC stage III or IV). Mean (SD) total delay from symptom onset to initiation of treatment was 407 (665) days because of patient (mean [SD], 198 [449] days) and health care system (mean [SD], 241 [556] days) delay. Fifty-two women (46.0%) had a history of clinical breast examination, and 23 (20.4%) had undergone previous mammography. Women who underwent a previous clinical breast examination were more likely to have shorter delays from symptom development to presentation compared with women who had never undergone a previous clinical breast examination (odds ratio, 2.92; 95% CI, 1.30-6.60; P = .01). Women diagnosed with shorter patient delay were more

  7. Neuroimaging of Fear-Associated Learning

    Science.gov (United States)

    Greco, John A; Liberzon, Israel

    2016-01-01

    Fear conditioning has been commonly used as a model of emotional learning in animals and, with the introduction of functional neuroimaging techniques, has proven useful in establishing the neurocircuitry of emotional learning in humans. Studies of fear acquisition suggest that regions such as amygdala, insula, anterior cingulate cortex, and hippocampus play an important role in acquisition of fear, whereas studies of fear extinction suggest that the amygdala is also crucial for safety learning. Extinction retention testing points to the ventromedial prefrontal cortex as an essential region in the recall of the safety trace, and explicit learning of fear and safety associations recruits additional cortical and subcortical regions. Importantly, many of these findings have implications in our understanding of the pathophysiology of psychiatric disease. Recent studies using clinical populations have lent insight into the changes in regional activity in specific disorders, and treatment studies have shown how pharmaceutical and other therapeutic interventions modulate brain activation during emotional learning. Finally, research investigating individual differences in neurotransmitter receptor genotypes has highlighted the contribution of these systems in fear-associated learning. PMID:26294108

  8. No interactions between previously associated 2-hour glucose gene variants and physical activity or BMI on 2-hour glucose levels

    DEFF Research Database (Denmark)

    Scott, Robert A; Chu, Audrey Y; Grarup, Niels

    2012-01-01

    to determine 2-h glucose levels is unknown. We meta-analyzed single nucleotide polymorphism (SNP) × BMI and SNP × physical activity (PA) interaction regression models for five SNPs previously associated with 2-h glucose levels from up to 22 studies comprising 54,884 individuals without diabetes. PA levels were...... dichotomized, with individuals below the first quintile classified as inactive (20%) and the remainder as active (80%). BMI was considered a continuous trait. Inactive individuals had higher 2-h glucose levels than active individuals (ß = 0.22 mmol/L [95% CI 0.13-0.31], P = 1.63 × 10(-6)). All SNPs were...... associated with 2-h glucose (ß = 0.06-0.12 mmol/allele, P = 1.53 × 10(-7)), but no significant interactions were found with PA (P > 0.18) or BMI (P = 0.04). In this large study of gene-lifestyle interaction, we observed no interactions between genetic and lifestyle factors, both of which were associated...

  9. Prevalence of Depression and Associated Factors in Non-institutionalized Older Adults With a Previous History of Falling.

    Science.gov (United States)

    Pellicer-García, Begoña; Antón-Solanas, Isabel; Moreno-González, Sergio; Castro-Sánchez, Enrique; Juárez-Vela, Raúl

    2017-10-01

    The purpose of this paper was to estimate the prevalence of depression and associated factors in people aged 65 or older with a history of falling in the last 12months. A cross-sectional descriptive study was performed involving a random sample of 213 participants from two social centers for older adults in the city of Zaragoza (Spain). The mean age of the participants was 77.3years (SD±7.0). Our findings reveal a prevalence of depression of 28.2% in the study sample, with older adults who were at a high risk of falling being more susceptible to developing depression. In conclusion, one in three elderly people who were at risk of suffering a fall in the 12months prior to data collection had symptoms of depression. This is in agreement with the results from previous studies, which confirm that there is a high prevalence of depression in elderly patients with a previous history of falls. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Orbital cellulitis caused by community-associated methicillin-resistant Staphylococcus aureus in a previously healthy neonate.

    Science.gov (United States)

    Lei, Tzu-Hui; Huang, Yhu-Chering; Chu, Yen-Chang; Lee, Chien-Yu; Lien, Reyin

    2013-04-01

    A 30-day-old, previously healthy, near-term neonate presented with fever and swelling of the left eye. Orbital cellulitis of the left eye was diagnosed by computed tomography. Both blood culture and pus that was drained from the orbital abscess were positive for methicillin-resistant Staphylococcus aureus (MRSA), which was found to be a strain indigenous to the local community by a molecular method. Using vancomycin therapy and surgical drainage, the infant recovered uneventfully. Orbital cellulitis in neonates may rapidly progress to abscess formation, even to sepsis, and S. aureus is the most common pathogen. With the increasing prevalence of community-associated MRSA, empiric antibiotics effective against MRSA should be first considered in endemic areas. Copyright © 2012. Published by Elsevier B.V.

  11. Diabetic ketoacidosis and diabetes associated with antipsychotic exposure among a previously diabetes-naive population with schizophrenia

    DEFF Research Database (Denmark)

    Polcwiartek, Christoffer; Kragholm, Kristian; Rohde, Christopher

    2017-01-01

    AIMS/HYPOTHESIS: Diabetic ketoacidosis (DKA) is a potentially fatal metabolic emergency of both type 1 and type 2 diabetes. Although there is a reduced risk of type 1 diabetes in schizophrenia, the incidence of DKA is tenfold higher than that of the general population. Thus, we aimed to investigate...... associations between exposure to antipsychotic medication (within 3 months prior to event) and DKA, type 1 diabetes and type 2 diabetes. We also reported related, clinically relevant outcomes. METHODS: Using a nested case-control study design, we identified cases of DKA, type 1 diabetes and type 2 diabetes...... in a previously diabetes-naive population with schizophrenia in Denmark from 1995 to 2014. Cases were matched (by age, sex and year of schizophrenia onset) 1:5 to schizophrenic control individuals who were alive and had not emigrated prior to event. Conditional logistic regression was used to compute ORs with 95...

  12. Sodium Valproate, a Histone Deacetylase Inhibitor, Is Associated With Reduced Stroke Risk After Previous Ischemic Stroke or Transient Ischemic Attack.

    Science.gov (United States)

    Brookes, Rebecca L; Crichton, Siobhan; Wolfe, Charles D A; Yi, Qilong; Li, Linxin; Hankey, Graeme J; Rothwell, Peter M; Markus, Hugh S

    2018-01-01

    A variant in the histone deacetylase 9 ( HDAC9 ) gene is associated with large artery stroke. Therefore, inhibiting HDAC9 might offer a novel secondary preventative treatment for ischemic stroke. The antiepileptic drug sodium valproate (SVA) is a nonspecific inhibitor of HDAC9. We tested whether SVA therapy given after ischemic stroke was associated with reduced recurrent stroke rate. Data were pooled from 3 prospective studies recruiting patients with previous stroke or transient ischemic attack and long-term follow-up: the South London Stroke Register, The Vitamins to Prevent Stroke Study, and the Oxford Vascular Study. Patients receiving SVA were compared with patients who received antiepileptic drugs other than SVA using survival analysis and Cox Regression. A total of 11 949 patients with confirmed ischemic event were included. Recurrent stroke rate was lower in patient taking SVA (17 of 168) than other antiepileptic drugs (105 of 530; log-rank survival analysis P =0.002). On Cox regression, controlling for potential cofounders, SVA remained associated with reduced stroke (hazard ratio=0.44; 95% confidence interval: 0.3-0.7; P =0.002). A similar result was obtained when patients taking SVA were compared with all cases not taking SVA (Cox regression, hazard ratio=0.47; 95% confidence interval: 0.29-0.77; P =0.003). These results suggest that exposure to SVA, an inhibitor of HDAC, may be associated with a lower recurrent stroke risk although we cannot exclude residual confounding in this study design. This supports the hypothesis that HDAC9 is important in the ischemic stroke pathogenesis and that its inhibition, by SVA or a more specific HDAC9 inhibitor, is worthy of evaluation as a treatment to prevent recurrent ischemic stroke. © 2017 The Authors.

  13. Neural dynamics of learning sound-action associations.

    Directory of Open Access Journals (Sweden)

    Adam McNamara

    Full Text Available A motor component is pre-requisite to any communicative act as one must inherently move to communicate. To learn to make a communicative act, the brain must be able to dynamically associate arbitrary percepts to the neural substrate underlying the pre-requisite motor activity. We aimed to investigate whether brain regions involved in complex gestures (ventral pre-motor cortex, Brodmann Area 44 were involved in mediating association between novel abstract auditory stimuli and novel gestural movements. In a functional resonance imaging (fMRI study we asked participants to learn associations between previously unrelated novel sounds and meaningless gestures inside the scanner. We use functional connectivity analysis to eliminate the often present confound of 'strategic covert naming' when dealing with BA44 and to rule out effects of non-specific reductions in signal. Brodmann Area 44, a region incorporating Broca's region showed strong, bilateral, negative correlation of BOLD (blood oxygen level dependent response with learning of sound-action associations during data acquisition. Left-inferior-parietal-lobule (l-IPL and bilateral loci in and around visual area V5, right-orbital-frontal-gyrus, right-hippocampus, left-para-hippocampus, right-head-of-caudate, right-insula and left-lingual-gyrus also showed decreases in BOLD response with learning. Concurrent with these decreases in BOLD response, an increasing connectivity between areas of the imaged network as well as the right-middle-frontal-gyrus with rising learning performance was revealed by a psychophysiological interaction (PPI analysis. The increasing connectivity therefore occurs within an increasingly energy efficient network as learning proceeds. Strongest learning related connectivity between regions was found when analysing BA44 and l-IPL seeds. The results clearly show that BA44 and l-IPL is dynamically involved in linking gesture and sound and therefore provides evidence that one of

  14. Awake, Offline Processing during Associative Learning.

    Science.gov (United States)

    Bursley, James K; Nestor, Adrian; Tarr, Michael J; Creswell, J David

    2016-01-01

    Offline processing has been shown to strengthen memory traces and enhance learning in the absence of conscious rehearsal or awareness. Here we evaluate whether a brief, two-minute offline processing period can boost associative learning and test a memory reactivation account for these offline processing effects. After encoding paired associates, subjects either completed a distractor task for two minutes or were immediately tested for memory of the pairs in a counterbalanced, within-subjects functional magnetic resonance imaging study. Results showed that brief, awake, offline processing improves memory for associate pairs. Moreover, multi-voxel pattern analysis of the neuroimaging data suggested reactivation of encoded memory representations in dorsolateral prefrontal cortex during offline processing. These results signify the first demonstration of awake, active, offline enhancement of associative memory and suggest that such enhancement is accompanied by the offline reactivation of encoded memory representations.

  15. Awake, Offline Processing during Associative Learning.

    Directory of Open Access Journals (Sweden)

    James K Bursley

    Full Text Available Offline processing has been shown to strengthen memory traces and enhance learning in the absence of conscious rehearsal or awareness. Here we evaluate whether a brief, two-minute offline processing period can boost associative learning and test a memory reactivation account for these offline processing effects. After encoding paired associates, subjects either completed a distractor task for two minutes or were immediately tested for memory of the pairs in a counterbalanced, within-subjects functional magnetic resonance imaging study. Results showed that brief, awake, offline processing improves memory for associate pairs. Moreover, multi-voxel pattern analysis of the neuroimaging data suggested reactivation of encoded memory representations in dorsolateral prefrontal cortex during offline processing. These results signify the first demonstration of awake, active, offline enhancement of associative memory and suggest that such enhancement is accompanied by the offline reactivation of encoded memory representations.

  16. Ontology Learning - Suggesting Associations from Text

    OpenAIRE

    Kvarv, Gøran Sveia

    2007-01-01

    In many applications, large-scale ontologies have to be constructed and maintained. A manual construction of an ontology is a time consuming and resource demanding process, often involving some domain experts. It would therefore be beneficial to support this process with tools that automates the construction of an ontology. This master thesis has examined the use of association rules for suggesting associations between words in text. In ontology learning, concepts are often extracted from d...

  17. Chitin-Like Molecules Associate with Cryptococcus neoformans Glucuronoxylomannan To Form a Glycan Complex with Previously Unknown Properties

    Science.gov (United States)

    Ramos, Caroline L.; Fonseca, Fernanda L.; Rodrigues, Jessica; Guimarães, Allan J.; Cinelli, Leonardo P.; Miranda, Kildare; Nimrichter, Leonardo; Casadevall, Arturo; Travassos, Luiz R.

    2012-01-01

    In prior studies, we demonstrated that glucuronoxylomannan (GXM), the major capsular polysaccharide of the fungal pathogen Cryptococcus neoformans, interacts with chitin oligomers at the cell wall-capsule interface. The structural determinants regulating these carbohydrate-carbohydrate interactions, as well as the functions of these structures, have remained unknown. In this study, we demonstrate that glycan complexes composed of chitooligomers and GXM are formed during fungal growth and macrophage infection by C. neoformans. To investigate the required determinants for the assembly of chitin-GXM complexes, we developed a quantitative scanning electron microscopy-based method using different polysaccharide samples as inhibitors of the interaction of chitin with GXM. This assay revealed that chitin-GXM association involves noncovalent bonds and large GXM fibers and depends on the N-acetyl amino group of chitin. Carboxyl and O-acetyl groups of GXM are not required for polysaccharide-polysaccharide interactions. Glycan complex structures composed of cryptococcal GXM and chitin-derived oligomers were tested for their ability to induce pulmonary cytokines in mice. They were significantly more efficient than either GXM or chitin oligomers alone in inducing the production of lung interleukin 10 (IL-10), IL-17, and tumor necrosis factor alpha (TNF-α). These results indicate that association of chitin-derived structures with GXM through their N-acetyl amino groups generates glycan complexes with previously unknown properties. PMID:22562469

  18. A model of olfactory associative learning

    Science.gov (United States)

    Tavoni, Gaia; Balasubramanian, Vijay

    We propose a mechanism, rooted in the known anatomy and physiology of the vertebrate olfactory system, by which presentations of rewarded and unrewarded odors lead to formation of odor-valence associations between piriform cortex (PC) and anterior olfactory nucleus (AON) which, in concert with neuromodulators release in the bulb, entrains a direct feedback from the AON representation of valence to a group of mitral cells (MCs). The model makes several predictions concerning MC activity during and after associative learning: (a) AON feedback produces synchronous divergent responses in a localized subset of MCs; (b) such divergence propagates to other MCs by lateral inhibition; (c) after learning, MC responses reconverge; (d) recall of the newly formed associations in the PC increases feedback inhibition in the MCs. These predictions have been confirmed in disparate experiments which we now explain in a unified framework. For cortex, our model further predicts that the response divergence developed during learning reshapes odor representations in the PC, with the effects of (a) decorrelating PC representations of odors with different valences, (b) increasing the size and reliability of those representations, and enabling recall correction and redundancy reduction after learning. Simons Foundation for Mathematical Modeling of Living Systems.

  19. Association between previously identified loci affecting telomere length and coronary heart disease (CHD in Han Chinese population

    Directory of Open Access Journals (Sweden)

    Ding H

    2014-05-01

    7675998. By one-way analysis of variance test, rs7675998 was associated with the onset age of CHD. CHD patients with the AA genotype of rs7675998 had significantly lower onset age (P<0.05.Conclusion: In a Chinese Han population, NAF1 gene encoding proteins with known function in telomere biology may influence both the possibility of and the age at onset of CHD, as previously reported in European studies.Keywords: coronary heart disease, gene, leucocyte telomere length

  20. Improvement of Self-regulated Learning in Mathematics through a Hypermedia Application: Differences based on Academic Performance and Previous Knowledge.

    Science.gov (United States)

    Cueli, Marisol; Rodríguez, Celestino; Areces, Débora; García, Trinidad; González-Castro, Paloma

    2017-12-04

    Self-regulation on behalf of the student is crucial in learning Mathematics through hypermedia applications and is an even greater challenge in these IT environments. Two aims are formulated. First, to analyze the effectiveness of a hypermedia tool in improving perceived knowledge of self-regulatory strategies and the perceived usage of the planning, executing and assessment strategy on behalf of students with low, medium and high levels of academic performance. Second, to analyze the effectiveness of the hypermedia tool in improving perceived usage of the strategy for planning, monitoring and evaluating on behalf of students with a perceived knowledge (low, medium and high). Participants were 624 students (aged 10-13), classified into a treatment group (TG; 391) and a comparative group (CG; 233). They completed a questionnaire on perceived knowledge (Perceived Knowledge of Self-Regulatory Strategies) and another one on perceived usage of the strategy for planning, performing and evaluating (Inventory of Self-regulatory Learning Processes). Univariate covariance analyses (ANCOVAs) and Student-t tests were used. ANCOVA results were not statistically significant. However, the linear contrast indicated a significant improvement in perceived knowledge of strategies among the TG with low, medium and high academic performance (p ≤ .001). Results are discussed in the light of past and future research.

  1. Cytogenetic Evolution in Myeloid Neoplasms at Relapse after Allogeneic Hematopoietic Cell Transplantation: Association with Previous Chemotherapy and Effect on Survival.

    Science.gov (United States)

    Ertz-Archambault, Natalie; Kosiorek, Heidi; Slack, James L; Lonzo, Melissa L; Greipp, Patricia T; Khera, Nandita; Kelemen, Katalin

    2017-05-01

    Cytogenetic evolution (CGE) in patients with myeloid neoplasms who relapsed after an allogeneic (allo) hematopoietic cell transplantation (HCT) has been evaluated by only few studies. The effect of the CGE on survival of relapsed allo-HCT recipients is not clear. The effect of previously received chemotherapy to induce CGE in this patient population has not been studied. The aims of our study are to (1) characterize the patterns of cytogenetic change in patients with myeloid neoplasms who relapsed after an allo-HCT, (2) evaluate the effect of CGE on survival, and (3) explore the association of CGE with previous chemotherapy (including the lines of salvage therapy, type of induction, and conditioning therapy). Of 49 patients with a myeloid malignancy (27 acute myeloid leukemia [AML], 19 myelodysplastic syndrome [MDS]/myeloproliferative neoplasm [MPN], and 3 chronic myelogenous leukemia) who relapsed after an allo-HCT, CGE was observed in 25 (51%), whereas 24 patients had unchanged cytogenetic findings at relapse. The CGE group carried more cytogenetic abnormalities at original diagnosis. The most frequent cytogenetic change was the acquisition of 3 or more new chromosomal abnormalities followed by acquisition of unbalanced abnormalities, aneuploidy, and emergence of apparently new clones unrelated to the original clone. The CGE cohort had higher proportion of MDS and MPN and fewer patients with de novo AML. Disease risk assessment category showed a trend to higher frequency of high-risk patients in the CGE group, though the difference was not statistically significant. Time from diagnosis to transplantation and time from transplantation to relapse were not different between the CGE and non-CGE groups. CGE and non-CGE cohorts had similar exposures to salvage therapy and to induction chemotherapy, as well as similar conditioning regimens; thus, no particular type of chemotherapy emerged as a predisposing factor to CGE. CGE was associated with significantly shortened

  2. The genes of the sulphoquinovose catabolism in Escherichia coli are also associated with a previously unknown pathway of lactose degradation.

    Science.gov (United States)

    Kaznadzey, Anna; Shelyakin, Pavel; Belousova, Evgeniya; Eremina, Aleksandra; Shvyreva, Uliana; Bykova, Darya; Emelianenko, Vera; Korosteleva, Anastasiya; Tutukina, Maria; Gelfand, Mikhail S

    2018-02-16

    Comparative genomics analysis of conserved gene cassettes demonstrated resemblance between a recently described cassette of genes involved in sulphoquinovose degradation in Escherichia coli K-12 MG1655 and a Bacilli cassette linked with lactose degradation. Six genes from both cassettes had similar functions related to carbohydrate metabolism, namely, hydrolase, aldolase, kinase, isomerase, transporter, and transcription factor. The Escherichia coli sulphoglycolysis cassette was thus predicted to be associated with lactose degradation. This prediction was confirmed experimentally: expression of genes coding for aldolase (yihT), isomerase (yihS), and kinase (yihV) was dramatically increased during growth on lactose. These genes were previously shown to be activated during growth on sulphoquinovose, so our observation may indicate multi-functional capabilities of the respective proteins. Transcription starts for yihT, yihV and yihW were mapped in silico, in vitro and in vivo. Out of three promoters for yihT, one was active only during growth on lactose. We further showed that switches in yihT transcription are controlled by YihW, a DeoR-family transcription factor in the Escherichia coli cassette. YihW acted as a carbon source-dependent dual regulator involved in sustaining the baseline growth in the absence of lac-operon, with function either complementary, or opposite to a global regulator of carbohydrate metabolism, cAMP-CRP.

  3. Screening of 134 single nucleotide polymorphisms (SNPs) previously associated with type 2 diabetes replicates association with 12 SNPs in nine genes.

    Science.gov (United States)

    Willer, Cristen J; Bonnycastle, Lori L; Conneely, Karen N; Duren, William L; Jackson, Anne U; Scott, Laura J; Narisu, Narisu; Chines, Peter S; Skol, Andrew; Stringham, Heather M; Petrie, John; Erdos, Michael R; Swift, Amy J; Enloe, Sareena T; Sprau, Andrew G; Smith, Eboni; Tong, Maurine; Doheny, Kimberly F; Pugh, Elizabeth W; Watanabe, Richard M; Buchanan, Thomas A; Valle, Timo T; Bergman, Richard N; Tuomilehto, Jaakko; Mohlke, Karen L; Collins, Francis S; Boehnke, Michael

    2007-01-01

    More than 120 published reports have described associations between single nucleotide polymorphisms (SNPs) and type 2 diabetes. However, multiple studies of the same variant have often been discordant. From a literature search, we identified previously reported type 2 diabetes-associated SNPs. We initially genotyped 134 SNPs on 786 index case subjects from type 2 diabetes families and 617 control subjects with normal glucose tolerance from Finland and excluded from analysis 20 SNPs in strong linkage disequilibrium (r(2) > 0.8) with another typed SNP. Of the 114 SNPs examined, we followed up the 20 most significant SNPs (P < 0.10) on an additional 384 case subjects and 366 control subjects from a population-based study in Finland. In the combined data, we replicated association (P < 0.05) for 12 SNPs: PPARG Pro12Ala and His447, KCNJ11 Glu23Lys and rs5210, TNF -857, SLC2A2 Ile110Thr, HNF1A/TCF1 rs2701175 and GE117881_360, PCK1 -232, NEUROD1 Thr45Ala, IL6 -598, and ENPP1 Lys121Gln. The replication of 12 SNPs of 114 tested was significantly greater than expected by chance under the null hypothesis of no association (P = 0.012). We observed that SNPs from genes that had three or more previous reports of association were significantly more likely to be replicated in our sample (P = 0.03), although we also replicated 4 of 58 SNPs from genes that had only one previous report of association.

  4. The reliability of the Associate Platinum digital foot scanner in measuring previously developed footprint characteristics: a technical note.

    Science.gov (United States)

    Papuga, M Owen; Burke, Jeanmarie R

    2011-02-01

    An ink pad and paper, pressure-sensitive platforms, and photography have previously been used to collect footprint data used in clinical assessment. Digital scanners have been widely used more recently to collect such data. The purpose of this study was to evaluate the intra- and interrater reliability of a flatbed digital image scanning technology to capture footprint data. This study used a repeated-measures design on 32 (16 male 16 female) healthy subjects. The following measured indices of footprint were recorded from 2-dimensional images of the plantar surface of the foot recorded with an Associate Platinum (Foot Levelers Inc, Roanoke, VA) digital foot scanner: Staheli index, Chippaux-Smirak index, arch angle, and arch index. Intraclass correlation coefficient (ICC) values were calculated to evaluate intrarater, interday, and interclinician reliability. The ICC values for intrarater reliability were greater than or equal to .817, indicating an excellent level of reproducibility in assessing the collected images. Analyses of variance revealed that there were no significant differences between raters for each index (P > .05). The ICC values also indicated excellent reliability (.881-.971) between days and clinicians in all but one of the indices of footprint, arch angle (.689), with good reliability between clinicians. The full-factorial analysis of variance model did not reveal any interaction effects (P > .05), which indicated that indices of footprint were not changing across days and clinicians. Scanning technology used in this study demonstrated good intra- and interrater reliability measurements of footprint indices, as demonstrated by high ICC values. Copyright © 2011 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

  5. Learned reward association improves visual working memory.

    Science.gov (United States)

    Gong, Mengyuan; Li, Sheng

    2014-04-01

    Statistical regularities in the natural environment play a central role in adaptive behavior. Among other regularities, reward association is potentially the most prominent factor that influences our daily life. Recent studies have suggested that pre-established reward association yields strong influence on the spatial allocation of attention. Here we show that reward association can also improve visual working memory (VWM) performance when the reward-associated feature is task-irrelevant. We established the reward association during a visual search training session, and investigated the representation of reward-associated features in VWM by the application of a change detection task before and after the training. The results showed that the improvement in VWM was significantly greater for items in the color associated with high reward than for those in low reward-associated or nonrewarded colors. In particular, the results from control experiments demonstrate that the observed reward effect in VWM could not be sufficiently accounted for by attentional capture toward the high reward-associated item. This was further confirmed when the effect of attentional capture was minimized by presenting the items in the sample and test displays of the change detection task with the same color. The results showed significantly larger improvement in VWM performance when the items in a display were in the high reward-associated color than those in the low reward-associated or nonrewarded colors. Our findings suggest that, apart from inducing space-based attentional capture, the learned reward association could also facilitate the perceptual representation of high reward-associated items through feature-based attentional modulation.

  6. Accounting for Individual Differences in Human Associative Learning.

    Directory of Open Access Journals (Sweden)

    Nicola C Byrom

    2013-09-01

    Full Text Available Associative learning has provided fundamental insights to understanding psychopathology. However, psychopathology occurs along a continuum and as such, identification of disruptions in processes of associative learning associated with aspects of psychopathology illustrates a general flexibility in human associative learning. A handful of studies have looked specifically at individual differences in human associative learning, but while much work has concentrated on accounting for flexibility in learning caused by external factors, there has been limited work considering how to model the influence of dispositional factors. This review looks at the range of individual differences in human associative learning that have been explored and the attempts to account for, and model, this flexibility. To fully understand human associative learning, further research needs to attend to the causes of variation in human learning.

  7. Exploration of Learning Strategies Associated With Aha Learning Moments.

    Science.gov (United States)

    Pilcher, Jobeth W

    2016-01-01

    Educators recognize aha moments as powerful aspects of learning. Yet limited research has been performed regarding how to promote these learning moments. This article describes an exploratory study of aha learning moments as experienced and described by participants. Findings showed use of visuals, scenarios, storytelling, Socratic questions, and expert explanation led to aha learning moments. The findings provide guidance regarding the types of learning strategies that can be used to promote aha moments.

  8. The clinical associate curriculum . the learning theory underpinning ...

    African Journals Online (AJOL)

    Drawing on the theories and practices of authentic learning, self-directed learning, whole-brain learning and collaborative learning, the curriculum has been transformed. The potential of this curriculum extends beyond the formal education part of the programme . into clinical associate practice, healthcare practice and, ...

  9. You see what you have learned. Evidence for an interrelation of associative learning and visual selective attention.

    Science.gov (United States)

    Feldmann-Wüstefeld, Tobias; Uengoer, Metin; Schubö, Anna

    2015-11-01

    Besides visual salience and observers' current intention, prior learning experience may influence deployment of visual attention. Associative learning models postulate that observers pay more attention to stimuli previously experienced as reliable predictors of specific outcomes. To investigate the impact of learning experience on deployment of attention, we combined an associative learning task with a visual search task and measured event-related potentials of the EEG as neural markers of attention deployment. In the learning task, participants categorized stimuli varying in color/shape with only one dimension being predictive of category membership. In the search task, participants searched a shape target while disregarding irrelevant color distractors. Behavioral results showed that color distractors impaired performance to a greater degree when color rather than shape was predictive in the learning task. Neurophysiological results show that the amplified distraction was due to differential attention deployment (N2pc). Experiment 2 showed that when color was predictive for learning, color distractors captured more attention in the search task (ND component) and more suppression of color distractor was required (PD component). The present results thus demonstrate that priority in visual attention is biased toward predictive stimuli, which allows learning experience to shape selection. We also show that learning experience can overrule strong top-down control (blocked tasks, Experiment 3) and that learning experience has a longer-term effect on attention deployment (tasks on two successive days, Experiment 4). © 2015 Society for Psychophysiological Research.

  10. Acute psychophysiological stress impairs human associative learning.

    Science.gov (United States)

    Ehlers, M R; Todd, R M

    2017-11-01

    Addiction is increasingly discussed asa disorder of associative learning processes, with both operant and classical conditioning contributing to the development of maladaptive habits. Stress has long been known to promote drug taking and relapse and has further been shown to shift behavior from goal-directed actions towards more habitual ones. However, it remains to be investigated how acute stress may influence simple associative learning processes that occur before a habit can be established. In the present study, healthy young adults were exposed to either acute stress or a control condition half an hour before performing simple classical and operant conditioning tasks. Psychophysiological measures confirmed successful stress induction. Results of the operant conditioning task revealed reduced instrumental responding under delayed acute stress that resembled behavioral responses to lower levels of reward. The classical conditioning experiment revealed successful conditioning in both experimental groups; however, explicit knowledge of conditioning as indicated by stimulus ratings differentiated the stress and control groups. These findings suggest that operant and classical conditioning are differentially influenced by the delayed effects of acute stress with important implications for the understanding of how new habitual behaviors are initially established. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. A Functional Genomic Analysis of NF1-Associated Learning Disabilities

    National Research Council Canada - National Science Library

    Tang, Shao-Jun

    2008-01-01

    Learning disabilities severely deteriorate the life of many NF1 patients. However, the pathogenic process for NF1-associated learning disabilities has not been fully understood and an effective therapy is not available...

  12. A Functional Genomic Analysis of NF1-Associated Learning Disabilities

    National Research Council Canada - National Science Library

    Tang, Shao-Jun

    2006-01-01

    Learning disabilities severely deteriorate the life of many NFI patients. However, the pathogenic process for NFI-associated learning disabilities has not been fully understood and an effective therapy is not available...

  13. A Functional Genomic Analysis of NF1-Associated Learning Disabilities

    National Research Council Canada - National Science Library

    Tang, Shao-Jun

    2007-01-01

    Learning disabilities severely deteriorate the life of many NF1 patients. However, the pathogenic process for NF1-associated learning disabilities has not been fully understood and an effective therapy is not available...

  14. The association between psychopathology of first-episode psychosis patients within the schizophrenia spectrum and previous offending

    DEFF Research Database (Denmark)

    Munkner, Runa; Haastrup, Soeren; Joergensen, Torben

    2009-01-01

    Patients with schizophrenia have been shown to have an increased risk of criminality. The aim was to describe possible psychopathological differences between schizophrenia spectrum patients with and without a criminal career before first-episode psychosis. In a multi-centre study, 16 psychiatric...... were linked with data concerning criminal and psychiatric history. No key characteristics were found to assist the early detection of criminal persons before first psychiatric hospital contact for a psychotic incident. However, when adjusted for sex, age, abuse, living conditions, marital status......, employment status and education, a primarily positive symptomatology was associated with a prior criminal career. The premorbid level of functioning and several function parameters were also significantly associated with criminal history. There are significant differences in psychopathology between...

  15. The association between psychopathology of first-episode psychosis patients within the schizophrenia spectrum and previous offending

    DEFF Research Database (Denmark)

    Munkner, Runa; Haastrup, Soeren; Joergensen, Torben

    2008-01-01

    treatment centres included and rated 477 patients with first-episode psychosis over a 2-year period on socio-demography, the Positive and Negative Syndrome Scale, OPerational CRITeria checklist, Global Assessment of Functioning, Premorbid Adjustment Scale and Self-report Insight Scale for psychosis. Data...... were linked with data concerning criminal and psychiatric history. No key characteristics were found to assist the early detection of criminal persons before first psychiatric hospital contact for a psychotic incident. However, when adjusted for sex, age, abuse, living conditions, marital status......, employment status and education, a primarily positive symptomatology was associated with a prior criminal career. The premorbid level of functioning and several function parameters were also significantly associated with criminal history. There are significant differences in psychopathology between...

  16. A genome-wide association study confirms previously reported loci for type 2 diabetes in Han Chinese.

    Directory of Open Access Journals (Sweden)

    Bin Cui

    Full Text Available BACKGROUND: Genome-wide association study (GWAS has identified more than 30 loci associated with type 2 diabetes (T2D in Caucasians. However, genomic understanding of T2D in Asians, especially Han Chinese, is still limited. METHODS AND PRINCIPAL FINDINGS: A two-stage GWAS was performed in Han Chinese from Mainland China. The discovery stage included 793 T2D cases and 806 healthy controls genotyped using Illumina Human 660- and 610-Quad BeadChips; and the replication stage included two independent case-control populations (a total of 4445 T2D cases and 4458 controls genotyped using TaqMan assay. We validated the associations of KCNQ1 (rs163182, p = 2.085×10(-17, OR 1.28 and C2CD4A/B (rs1370176, p = 3.677×10(-4, OR 1.124; rs1436953, p = 7.753×10(-6, OR 1.141; rs7172432, p = 4.001×10(-5, OR 1.134 in Han Chinese. CONCLUSIONS AND SIGNIFICANCE: Our study represents the first GWAS of T2D with both discovery and replication sample sets recruited from Han Chinese men and women residing in Mainland China. We confirmed the associations of KCNQ1 and C2CD4A/B with T2D, with the latter for the first time being examined in Han Chinese. Arguably, eight more independent loci were replicated in our GWAS.

  17. Reduced autobiographical memory specificity is associated with impaired discrimination learning in anxiety disorder patients

    Science.gov (United States)

    Lenaert, Bert; Boddez, Yannick; Vervliet, Bram; Schruers, Koen; Hermans, Dirk

    2015-01-01

    Associative learning plays an important role in the development of anxiety disorders, but a thorough understanding of the variables that impact such learning is still lacking. We investigated whether individual differences in autobiographical memory specificity are related to discrimination learning and generalization. In an associative learning task, participants learned the association between two pictures of female faces and a non-aversive outcome. Subsequently, six morphed pictures functioning as generalization stimuli (GSs) were introduced. In a sample of healthy participants (Study 1), we did not find evidence for differences in discrimination learning as a function of memory specificity. In a sample of anxiety disorder patients (Study 2), individuals who were characterized by low memory specificity showed deficient discrimination learning relative to high specific individuals. In contrast to previous findings, results revealed no effect of memory specificity on generalization. These results indicate that impaired discrimination learning, previously shown in patients suffering from an anxiety disorder, may be—in part—due to limited memory specificity. Together, these studies emphasize the importance of incorporating cognitive variables in associative learning theories and their implications for the development of anxiety disorders. In addition, re-analyses of the data (Study 3) showed that patients suffering from panic disorder showed higher outcome expectancies in the presence of the stimulus that was never followed by an outcome during discrimination training, relative to patients suffering from other anxiety disorders and healthy participants. Because we used a neutral, non-aversive outcome (i.e., drawing of a lightning bolt), these data suggest that learning abnormalities in panic disorder may not be restricted to fear learning, but rather reflect a more general associative learning deficit that also manifests in fear irrelevant contexts. PMID

  18. Reduced autobiographical memory specificity is associated with impaired discrimination learning in anxiety disorder patients

    Directory of Open Access Journals (Sweden)

    Bert eLenaert

    2015-07-01

    Full Text Available Associative learning plays an important role in the development of anxiety disorders, but a thorough understanding of the variables that impact such learning is still lacking. We investigated whether individual differences in autobiographical memory specificity are related to discrimination learning and generalization. In an associative learning task, participants learned the association between two pictures of female faces and a non-aversive outcome. Subsequently, six morphed pictures functioning as generalization stimuli (GSs were introduced. In a sample of healthy participants (Study 1, we did not find evidence for differences in discrimination learning as a function of memory specificity. In a sample of anxiety disorder patients (Study 2, individuals who were characterized by low memory specificity showed deficient discrimination learning relative to high specific individuals. In contrast to previous findings, results revealed no effect of memory specificity on generalization. These results indicate that impaired discrimination learning, previously shown in patients suffering from an anxiety disorder, may be – in part – due to limited memory specificity. Together, these studies emphasize the importance of incorporating cognitive variables in associative learning theories and their implications for the development of anxiety disorders. In addition, re-analyses of the data (Study 3 showed that patients suffering from panic disorder showed higher outcome expectancies in the presence of the stimulus that was never followed by an outcome during discrimination training, relative to patients suffering from other anxiety disorders and healthy participants. Because we used a neutral, non-aversive outcome (i.e., drawing of a lightning bolt, these data suggest that learning abnormalities in panic disorder may not be restricted to fear learning, but rather reflect a more general associative learning deficit that also manifests in fear irrelevant

  19. Choline acetyltransferase in the hippocampus is associated with learning strategy preference in adult male rats.

    Science.gov (United States)

    Hawley, Wayne R; Witty, Christine F; Daniel, Jill M; Dohanich, Gary P

    2015-08-01

    One principle of the multiple memory systems hypothesis posits that the hippocampus-based and striatum-based memory systems compete for control over learning. Consistent with this notion, previous research indicates that the cholinergic system of the hippocampus plays a role in modulating the preference for a hippocampus-based place learning strategy over a striatum-based stimulus--response learning strategy. Interestingly, in the hippocampus, greater activity and higher protein levels of choline acetyltransferase (ChAT), the enzyme that synthesizes acetylcholine, are associated with better performance on hippocampus-based learning and memory tasks. With this in mind, the primary aim of the current study was to determine if higher levels of ChAT and the high-affinity choline uptake transporter (CHT) in the hippocampus were associated with a preference for a hippocampus-based place learning strategy on a task that also could be solved by relying on a striatum-based stimulus--response learning strategy. Results confirmed that levels of ChAT in the dorsal region of the hippocampus were associated with a preference for a place learning strategy on a water maze task that could also be solved by adopting a stimulus-response learning strategy. Consistent with previous studies, the current results support the hypothesis that the cholinergic system of the hippocampus plays a role in balancing competition between memory systems that modulate learning strategy preference. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Computed tomography in the evaluation of abdominal fat distribution associated with a hyperlipidic diet in previously undernourished rats

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Carlos Alberto Soares da [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Faculdade de Ciencias Medicas. Program of Post-graduation in Clinical and Experimental Physiopathology; Alves, Erika Gomes; Gonzalez, Gabriele Paula; Barbosa, Thais Barcellos Cortez; Lima, Veronica Demarco; Nascimento, Renata; Moura, Egberto Gaspar de; Saba, Celly Cristina Alves do Nascimento [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Inst. de Biologia Roberto Alcantara Gomes. Dept. of Physiological Sciences]. E-mail: cellysaba@terra.com.br; Monteiro, Alexandra Maria Vieira [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Faculdade de Ciencias Medicas

    2007-09-15

    Objective: To study, by means of computed tomography, the repercussion of post-weaning dietary supplementation with soy oil or canola oil on the abdominal fat distribution in previously undernourished rats. Materials and methods: Dams submitted to 50% food restriction (FR) compared with dams receiving a standard diet (C). After weaning, undernourished rats received a diet supplemented with 19% soy oil (19% FR-soy) or 19% canola oil (19% FR-canola). Rats in the control group received a diet with 7% soy oil (7% C-soy) until the end of the experimental period. At the age of 60 days old, the rats were submitted to computed tomography for evaluation of total abdominal and visceral fat area. The rats' length and body mass were evaluated and, after their sacrifice, the abdominal fat depots were excised weighted. The data are reported as mean {+-} mean standard error, with p < 0.05 considered as significance level. Results: Rats in the group 19% FR presented similar length, body weight and visceral fat mass. As a whole, the evaluations have shower results significantly lower in relation to the control group (7% C-soy). However, computed tomography has found significant differences in abdominal fat distribution for the groups 19% FR-soy and 19% FR-canola. Conclusion: Computed tomography has demonstrated that the abdominal fat distribution may be dependent on the type of vegetable oil included in the diet. (author)

  1. Partial extinction of a conditioned context enhances preference for elements previously associated with cocaine but not with chocolate.

    Science.gov (United States)

    Orsini, C; Bonito-Oliva, A; Montanari, C; Conversi, D; Cabib, S

    2013-08-15

    Drug-associated stimuli are crucial to reinstatement of drug-seeking after periods of abstinence, representing a central problem in treatment of addiction. The present study investigated the influence of partial extinction of the conditioned context on the expression of conditioned place preference (CPP). Mice of the inbred DBA/2J strain were conditioned with cocaine or chocolate in a context identified by multiple elements (A+B) and subsequently CPP expression was evaluated in a context containing only one element (A or B) or both (A+B). Cocaine- and chocolate-conditioned mice showed CPP in presence of the original compound stimulus. However, cocaine-conditioned mice did not show CPP when tested in A or B context, while chocolate-conditioned mice did show CPP to single element context. After conditioning mice were exposed to extinction training of the context A or B and then tested for CPP 1 and 9 days after the end of the extinction (days 9 and 18). Cocaine-conditioned mice showed CPP 9 days after extinction while chocolate-conditioned mice were relatively insensitive to the extinction procedure on day 1 after extinction, but they did not show CPP for the partial or the original compound 9 days after extinction. Cocaine-conditioned mice not submitted to the extinction training (simple passage of time) or submitted to a Sham-extinction procedure (saline injections and confinement in a new environment) did not show CPP on day 9 or 18. Cocaine-conditioned mice exposed to extinction training showed increased c-Fos expression in several brain areas in comparison to mice exposed to Sham-extinction. The extinction procedure did not specifically reduce behavioral sensitization. The results suggest that extinction training involving only elements of a drug-associated context can result in increased associative strength of those elements. © 2013.

  2. Easy to Learn, Hard to Suppress: The Impact of Learned Stimulus-Outcome Associations on Subsequent Action Control

    Science.gov (United States)

    Van Wouwe, N.C.; van den Wildenberg, W.P.M.; Ridderinkhof, K. R.; Claassen, D.O.; Neimat, J.S.; Wylie, S.A.

    2015-01-01

    The inhibition of impulsive response tendencies that conflict with goal-directed action is a key component of executive control. An emerging literature reveals that the proficiency of inhibitory control is modulated by expected or unexpected opportunities to earn reward or avoid punishment. However, less is known about how inhibitory control is impacted by the processing of task-irrelevant stimulus information that has been associated previously with particular outcomes (reward or punishment) or response tendencies (action or inaction). We hypothesized that stimulus features associated with particular action-valence tendencies, even though task irrelevant, would modulate inhibitory control processes. Participants first learned associations between stimulus features (color), actions, and outcomes using an action-valence learning task that orthogonalizes action (action, inaction) and valence (reward, punishment). Next, these stimulus features were embedded in a Simon task as a task-irrelevant stimulus attribute. We analyzed the effects of action-valence associations on the Simon task by means of distributional analysis to reveal the temporal dynamics. Learning patterns replicated previously reported biases; inherent, Pavlovian-like mappings (action-reward, inaction-punishment avoidance) were easier to learn than mappings conflicting with these biases (action-punishment avoidance, inaction-reward). More importantly, results from two experiments demonstrated that the easier to learn, Pavlovian-like action-valence associations interfered with the proficiency of inhibiting impulsive actions in the Simon task. Processing conflicting associations led to more proficient inhibitory control of impulsive actions, similar to Simon trials without any association. Fast impulsive errors were reduced for trials associated with punishment in comparison to reward trials or trials without any valence association. These findings provide insight into the temporal dynamics of task

  3. Associative learning and the control of human dietary behavior.

    Science.gov (United States)

    Brunstrom, Jeffrey M

    2007-07-01

    Most of our food likes and disliked are learned. Relevant forms of associative learning have been identified in animals. However, observations of the same associative processes are relatively scarce in humans. The first section of this paper outlines reasons why this might be the case. Emphasis is placed on recent research exploring individual differences and the importance or otherwise of hunger and contingency awareness. The second section briefly considers the effect of learning on meal size, and the author revisits the question of how learned associations might come to influence energy intake in humans.

  4. The development of associate learning in school age children.

    Directory of Open Access Journals (Sweden)

    Brian T Harel

    Full Text Available Associate learning is fundamental to the acquisition of knowledge and plays a critical role in the everyday functioning of the developing child, though the developmental course is still unclear. This study investigated the development of visual associate learning in 125 school age children using the Continuous Paired Associate Learning task. As hypothesized, younger children made more errors than older children across all memory loads and evidenced decreased learning efficiency as memory load increased. Results suggest that age-related differences in performance largely reflect continued development of executive function in the context of relatively developed memory processes.

  5. Effect of student emotion-associations on architectural color design of educational spaces in 3D Virtual Learning Environments

    OpenAIRE

    Saleeb, Noha; Dafoulas, George

    2010-01-01

    Research has been previously dedicated to investigating effects of traditional classroom colors on students’ enjoyment, interactions and learning experiences. Students’ emotional reactions towards different colors were also depicted and analyzed. However sparse research has been conducted representing analogous studies of students’ color-emotional associations towards e-learning spaces in 3D virtual learning environments. This study investigates positive and negative emotional associations ex...

  6. Guidance of spatial attention during associative learning: Contributions of predictability and intention to learn.

    Science.gov (United States)

    Do Carmo Blanco, Noelia; Allen, John J B

    2018-03-23

    Expectations of an event can facilitate its neural processing. One of the ways we build expectations is through associative learning. Interestingly, the learning of contingencies between events can also occur without intention. Here, we study feature-based attention during associative learning, by asking how a learned association between a cue and a target outcome impacts the attention allocated to this outcome. Moreover, we investigate attention in learning depending on the intention to learn the association. We used an associative learning paradigm where we manipulated outcome predictability and intention to learn an association within streams of cue-target outcome visual stimuli, while stimulus characteristics and probability were held constant. In order to measure the event-related component N2pc, widely recognized to reflect allocation of spatial attention, every outcome was embedded among distractors. Importantly, the location of the target outcome could not be anticipated. We found that predictable target outcomes showed an increased spatial attention as indexed by a greater N2pc component. A later component, the P300, was sensitive to the intention to learn the association between the cue and the target outcome. The current study confirms the remarkable ability of the brain to extract and update predictive information, in accordance with a predictive-coding model of brain function. Associative learning can guide a visual search and shape covert attentional selection in our rich environments. © 2018 Society for Psychophysiological Research.

  7. Commentary: the truth and value of theories of associative learning

    NARCIS (Netherlands)

    Beckers, T.; Vervliet, B.

    2009-01-01

    In this commentary, we assess the propositional approach to associative learning not only in terms of veridicality and falsifiability, but also in heuristic value. We remark that it has furthered our knowledge and understanding of human, as well as animal, associative learning. At the same time, we

  8. The Association between Learning Styles and Perception of Teaching Quality

    Science.gov (United States)

    Jepsen, Denise M.; Varhegyi, Melinda M.; Teo, Stephen T. T.

    2015-01-01

    Purpose: Although learning styles and teaching quality have been studied separately, the association between the association between the two has yet to be identified. The purpose of this paper is to establish the relationship between students' learning styles with students' perceptions of teaching quality. Design/methodology/approach: The study…

  9. Two Ways of Learning Brand Associations

    NARCIS (Netherlands)

    S.M.J. van Osselaer (Stijn); C. Janiszewski (Chris)

    2001-01-01

    textabstractFour studies show that consumers have not one but two distinct learning processes that allow them to use brand names and other product features to predict consumption benefits. The first learning process is a relatively unfocused process in which all stimulus elements get

  10. The endocannabinoid system and associative learning and memory in zebrafish.

    Science.gov (United States)

    Ruhl, Tim; Moesbauer, Kirstin; Oellers, Nadine; von der Emde, Gerhard

    2015-09-01

    In zebrafish the medial pallium of the dorsal telencephalon represents an amygdala homolog structure, which is crucially involved in emotional associative learning and memory. Similar to the mammalian amygdala, the medial pallium contains a high density of endocannabinoid receptor CB1. To elucidate the role of the zebrafish endocannabinoid system in associative learning, we tested the influence of acute and chronic administration of receptor agonists (THC, WIN55,212-2) and antagonists (Rimonabant, AM-281) on two different learning paradigms. In an appetitively motivated two-alternative choice paradigm, animals learned to associate a certain color with a food reward. In a second set-up, a fish shuttle-box, animals associated the onset of a light stimulus with the occurrence of a subsequent electric shock (avoidance conditioning). Once fish successfully had learned to solve these behavioral tasks, acute receptor activation or inactivation had no effect on memory retrieval, suggesting that established associative memories were stable and not alterable by the endocannabinoid system. In both learning tasks, chronic treatment with receptor antagonists improved acquisition learning, and additionally facilitated reversal learning during color discrimination. In contrast, chronic CB1 activation prevented aversively motivated acquisition learning, while different effects were found on appetitively motivated acquisition learning. While THC significantly improved behavioral performance, WIN55,212-2 significantly impaired color association. Our findings suggest that the zebrafish endocannabinoid system can modulate associative learning and memory. Stimulation of the CB1 receptor might play a more specific role in acquisition and storage of aversive learning and memory, while CB1 blocking induces general enhancement of cognitive functions. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. The role of association in early word-learning

    Directory of Open Access Journals (Sweden)

    Scott P Johnson

    2012-08-01

    Full Text Available Word-learning likely involves a multiplicity of components, some domain-general, others domain-specific. Against the background of recent studies that suggest that word-learning is domain-specific, we investigated the associative component of word-learning. Seven- and 14-month-old infants viewed a pair of events in which a monkey or a truck moved back and forth, accompanied by a sung syllable or a tone, matched for pitch. Following habituation, infants were presented with displays in which the visual-auditory pairings were preserved or switched, and looked longer at the switch events when exposure time was sufficient to learn the intermodal association. At 7 months, performance on speech and tones conditions was statistically identical; at 14 months, infants had begun to favor speech. Thus, the associative component of word-learning does not appear (in contrast to rule-learning, Marcus et al., 2007 to initially privilege speech.

  12. Comfort and experience with online learning: trends over nine years and associations with knowledge.

    Science.gov (United States)

    Cook, David A; Thompson, Warren G

    2014-07-01

    Some evidence suggests that attitude toward computer-based instruction is an important determinant of success in online learning. We sought to determine how comfort using computers and perceptions of prior online learning experiences have changed over the past decade, and how these associate with learning outcomes. Each year from 2003-2011 we conducted a prospective trial of online learning. As part of each year's study, we asked medicine residents about their comfort using computers and if their previous experiences with online learning were favorable. We assessed knowledge using a multiple-choice test. We used regression to analyze associations and changes over time. 371 internal medicine and family medicine residents participated. Neither comfort with computers nor perceptions of prior online learning experiences showed a significant change across years (p > 0.61), with mean comfort rating 3.96 (maximum 5 = very comfortable) and mean experience rating 4.42 (maximum 6 = strongly agree [favorable]). Comfort showed no significant association with knowledge scores (p = 0.39) but perceptions of prior experiences did, with a 1.56% rise in knowledge score for a 1-point rise in experience score (p = 0.02). Correlations among comfort, perceptions of prior experiences, and number of prior experiences were all small and not statistically significant. Comfort with computers and perceptions of prior experience with online learning remained stable over nine years. Prior good experiences (but not comfort with computers) demonstrated a modest association with knowledge outcomes, suggesting that prior course satisfaction may influence subsequent learning.

  13. Working memory and reward association learning impairments in obesity.

    Science.gov (United States)

    Coppin, Géraldine; Nolan-Poupart, Sarah; Jones-Gotman, Marilyn; Small, Dana M

    2014-12-01

    Obesity has been associated with impaired executive functions including working memory. Less explored is the influence of obesity on learning and memory. In the current study we assessed stimulus reward association learning, explicit learning and memory and working memory in healthy weight, overweight and obese individuals. Explicit learning and memory did not differ as a function of group. In contrast, working memory was significantly and similarly impaired in both overweight and obese individuals compared to the healthy weight group. In the first reward association learning task the obese, but not healthy weight or overweight participants consistently formed paradoxical preferences for a pattern associated with a negative outcome (fewer food rewards). To determine if the deficit was specific to food reward a second experiment was conducted using money. Consistent with Experiment 1, obese individuals selected the pattern associated with a negative outcome (fewer monetary rewards) more frequently than healthy weight individuals and thus failed to develop a significant preference for the most rewarded patterns as was observed in the healthy weight group. Finally, on a probabilistic learning task, obese compared to healthy weight individuals showed deficits in negative, but not positive outcome learning. Taken together, our results demonstrate deficits in working memory and stimulus reward learning in obesity and suggest that obese individuals are impaired in learning to avoid negative outcomes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Chronological age and its impact on associative learning proficiency and brain structure in middle adulthood.

    Science.gov (United States)

    Diwadkar, Vaibhav A; Bellani, Marcella; Ahmed, Rizwan; Dusi, Nicola; Rambaldelli, Gianluca; Perlini, Cinzia; Marinelli, Veronica; Ramaseshan, Karthik; Ruggeri, Mirella; Bambilla, Paolo

    2016-01-15

    The rate of biological change in middle-adulthood is relatively under-studied. Here, we used behavioral testing in conjunction with structural magnetic resonance imaging to examine the effects of chronological age on associative learning proficiency and on brain regions that previous functional MRI studies have closely related to the domain of associative learning. Participants (n=66) completed a previously established associative learning paradigm, and consented to be scanned using structural magnetic resonance imaging. Age-related effects were investigated both across sub-groups in the sample (younger vs. older) and across the entire sample (using regression approaches). Chronological age had substantial effects on learning proficiency (independent of IQ and Education Level), with older adults showing a decrement compared to younger adults. In addition, decreases in estimated gray matter volume were observed in multiple brain regions including the hippocampus and the dorsal prefrontal cortex, both of which are strongly implicated in associative learning. The results suggest that middle adulthood may be a more dynamic period of life-span change than previously believed. The conjunctive application of narrowly focused tasks, with conjointly acquired structural MRI data may allow us to enrich the search for, and the interpretation of, age-related changes in cross-sectional samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Active Learning "Not" Associated with Student Learning in a Random Sample of College Biology Courses

    Science.gov (United States)

    Andrews, T. M.; Leonard, M. J.; Colgrove, C. A.; Kalinowski, S. T.

    2011-01-01

    Previous research has suggested that adding active learning to traditional college science lectures substantially improves student learning. However, this research predominantly studied courses taught by science education researchers, who are likely to have exceptional teaching expertise. The present study investigated introductory biology courses…

  16. Novel associative-memory-based self-learning neurocontrol model

    Science.gov (United States)

    Chen, Ke

    1992-09-01

    Intelligent control is an important field of AI application, which is closely related to machine learning, and the neurocontrol is a kind of intelligent control that controls actions of a physical system or a plant. Linear associative memory model is a good analytic tool for artificial neural networks. In this paper, we present a novel self-learning neurocontrol on the basis of the linear associative memory model to support intelligent control. Using our self-learning neurocontrol model, the learning process is viewed as an extension of one of J. Piaget's developmental stages. After a particular linear associative model developed by us is presented, a brief introduction to J. Piaget's cognitive theory is described as the basis of our self-learning style control. It follows that the neurocontrol model is presented, which usually includes two learning stages, viz. primary learning and high-level learning. As a demonstration of our neurocontrol model, an example is also presented with simulation techniques, called that `bird' catches an aim. The tentative experimental results show that the learning and controlling performance of this approach is surprisingly good. In conclusion, future research is pointed out to improve our self-learning neurocontrol model and explore other areas of application.

  17. Associations among Sleep Problems, Learning Difficulties and Substance Use in Adolescence

    Science.gov (United States)

    Fakier, Nuraan; Wild, Lauren G.

    2011-01-01

    This study investigated the relationships among sleep problems, learning difficulties and substance use in adolescence. Previous research suggests that these variables share an association with executive functioning deficits, and are intertwined. The sample comprised 427 adolescents (M age = 16 years) attending remedial schools and 276 adolescents…

  18. Pigeons acquire multiple categories in parallel via associative learning: a parallel to human word learning?

    Science.gov (United States)

    Wasserman, Edward A; Brooks, Daniel I; McMurray, Bob

    2015-03-01

    Might there be parallels between category learning in animals and word learning in children? To examine this possibility, we devised a new associative learning technique for teaching pigeons to sort 128 photographs of objects into 16 human language categories. We found that pigeons learned all 16 categories in parallel, they perceived the perceptual coherence of the different object categories, and they generalized their categorization behavior to novel photographs from the training categories. More detailed analyses of the factors that predict trial-by-trial learning implicated a number of factors that may shape learning. First, we found considerable trial-by-trial dependency of pigeons' categorization responses, consistent with several recent studies that invoke this dependency to claim that humans acquire words via symbolic or inferential mechanisms; this finding suggests that such dependencies may also arise in associative systems. Second, our trial-by-trial analyses divulged seemingly irrelevant aspects of the categorization task, like the spatial location of the report responses, which influenced learning. Third, those trial-by-trial analyses also supported the possibility that learning may be determined both by strengthening correct stimulus-response associations and by weakening incorrect stimulus-response associations. The parallel between all these findings and important aspects of human word learning suggests that associative learning mechanisms may play a much stronger part in complex human behavior than is commonly believed. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. A meta-analysis of drug resistant tuberculosis in Sub-Saharan Africa: how strongly associated with previous treatment and HIV co-infection?

    Science.gov (United States)

    Berhan, Asres; Berhan, Yifru; Yizengaw, Desalegn

    2013-11-01

    In Sub-Saharan Africa, the fight against tuberculosis (TB) has encountered a great challenge because of the emergence of drug resistant TB strains and the high prevalence of HIV infection. The aim of this meta-analysis was to determine the association of drug-resistant TB with anti-TB drug treatment history and HIV co-infection. After electronic based literature search in the databases of Medline, HINARI, EMBASE and the Cochrane library, article selection and data extraction were carried out. HIV co-infection and previous history of TB treatment were used as predictors for the occurrence of any anti-TB drug resistant or multiple drug resistant TB (MDR-TB). The risk ratios for each included study and for the pooled sample were computed using the random-effects model. Heterogeneity test, sensitivity analyses and funnel plots were also done. The pooled analysis showed that the risk of developing drug-resistant TB to at least one anti-TB drug was about 3 times higher in individuals who had a previous history of anti-TB treatment than new TB cases. The risk of having MDR-TB in previously anti-TB treated TB cases was more than 5-fold higher than that of new TB cases. Resistance to Ethambutol and Rifampicin was more than fivefold higher among the previously treated with anti-TB drugs. However, HIV infection was not associated with drug-resistant TB. There was a strong association of previous anti-TB treatment with MDR-TB. Primary treatment warrants special emphasis, and screening for anti-TB drugs sensitivity has to be strengthened.

  20. Mortality and cardiovascular risk associated with different insulin secretagogues compared with metformin in type 2 diabetes, with or without a previous myocardial infarction: a nationwide study

    DEFF Research Database (Denmark)

    Schramm, Tina Ken; Gislason, Gunnar Hilmar; Vaag, Allan

    2011-01-01

    Aims The impact of insulin secretagogues (ISs) on long-term major clinical outcomes in type 2 diabetes remains unclear. We examined mortality and cardiovascular risk associated with all available ISs compared with metformin in a nationwide study. Methods and results All Danish residents >20 years......, initiating single-agent ISs or metformin between 1997 and 2006 were followed for up to 9 years (median 3.3 years) by individual-level linkage of nationwide registers. All-cause mortality, cardiovascular mortality, and the composite of myocardial infarction (MI), stroke, and cardiovascular mortality...... associated with individual ISs were investigated in patients with or without previous MI by multivariable Cox proportional-hazard analyses including propensity analyses. A total of 107 806 subjects were included, of whom 9607 had previous MI. Compared with metformin, glimepiride (hazard ratios and 95...

  1. [Factors associated with self-directed learning among medical students].

    Science.gov (United States)

    Spormann R, Camila; Pérez V, Cristhian; Fasce H, Eduardo; Ortega B, Javiera; Bastías V, Nancy; Bustamante D, Carolina; Ibáñez G, Pilar

    2015-03-01

    Self-directed learning is a skill that must be taught and evaluated in future physicians. To analyze the association between self-directed learning, self-esteem, self-efficacy, time management and academic commitment among medical students. The self-directed learning, Rosemberg self-esteem, general self- efficacy, time management and Utrecht work engagement scales were applied to 297 first year medical students. A multiple regression analysis showed a significant association between self-efficacy, time management and academic commitment with self-directed learning. Self-esteem and satisfaction with studies did not enter in the model. self-esteem, academic commitment and a good time management were associated with self-directed learning in these students.

  2. An associative account of the development of word learning.

    Science.gov (United States)

    Sloutsky, Vladimir M; Yim, Hyungwook; Yao, Xin; Dennis, Simon

    2017-09-01

    Word learning is a notoriously difficult induction problem because meaning is underdetermined by positive examples. How do children solve this problem? Some have argued that word learning is achieved by means of inference: young word learners rely on a number of assumptions that reduce the overall hypothesis space by favoring some meanings over others. However, these approaches have difficulty explaining how words are learned from conversations or text, without pointing or explicit instruction. In this research, we propose an associative mechanism that can account for such learning. In a series of experiments, 4-year-olds and adults were presented with sets of words that included a single nonsense word (e.g. dax). Some lists were taxonomic (i.,e., all items were members of a given category), some were associative (i.e., all items were associates of a given category, but not members), and some were mixed. Participants were asked to indicate whether the nonsense word was an animal or an artifact. Adults exhibited evidence of learning when lists consisted of either associatively or taxonomically related items. In contrast, children exhibited evidence of word learning only when lists consisted of associatively related items. These results present challenges to several extant models of word learning, and a new model based on the distinction between syntagmatic and paradigmatic associations is proposed. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. [Associative Learning between Orientation and Color in Early Visual Areas].

    Science.gov (United States)

    Amano, Kaoru; Shibata, Kazuhisa; Kawato, Mitsuo; Sasaki, Yuka; Watanabe, Takeo

    2017-08-01

    Associative learning is an essential neural phenomenon where the contingency of different items increases after training. Although associative learning has been found to occur in many brain regions, there is no clear evidence that associative learning of visual features occurs in early visual areas. Here, we developed an associative decoded functional magnetic resonance imaging (fMRI) neurofeedback (A-DecNef) to determine whether associative learning of color and orientation can be induced in early visual areas. During the three days' training, A-DecNef induced fMRI signal patterns that corresponded to a specific target color (red) mostly in early visual areas while a vertical achromatic grating was simultaneously, physically presented to participants. Consequently, participants' perception of "red" was significantly more frequently than that of "green" in an achromatic vertical grating. This effect was also observed 3 to 5 months after training. These results suggest that long-term associative learning of two different visual features such as color and orientation, was induced most likely in early visual areas. This newly extended technique that induces associative learning may be used as an important tool for understanding and modifying brain function, since associations are fundamental and ubiquitous with respect to brain function.

  4. I. P. PAVLOV: 100 YEARS OF RESERACH ON ASSOCIATIVE LEARNING

    Directory of Open Access Journals (Sweden)

    GERMÁN GUTIÉRREZ

    2005-07-01

    Full Text Available A biographical summary of Ivan Pavlov is presented, emphasizing his academic formation and achievements, and hiscontributions to general science and psychology. His main findings on associative learning are described and three areasof current development in this area are discussed: the study of behavioral mechanisms, the study of neurobiologicalmechanisms and the functional role of learning.

  5. Differential Recruitment of Distinct Amygdalar Nuclei across Appetitive Associative Learning

    Science.gov (United States)

    Cole, Sindy; Powell, Daniel J.; Petrovich, Gorica D.

    2013-01-01

    The amygdala is important for reward-associated learning, but how distinct cell groups within this heterogeneous structure are recruited during appetitive learning is unclear. Here we used Fos induction to map the functional amygdalar circuitry recruited during early and late training sessions of Pavlovian appetitive conditioning. We found that a…

  6. Associative Learning Improves Visual Working Memory Performance

    Science.gov (United States)

    Olson, Ingrid R.; Jiang, Yuhong; Moore, Katherine Sledge

    2005-01-01

    The ability to remember visual stimuli over a short delay period is limited by the small capacity of visual working memory (VWM). Here the authors investigate the role of learning in enhancing VWM. Participants saw 2 spatial arrays separated by a 1-s interval. The 2 arrays were identical except for 1 location. Participants had to detect the…

  7. Associative Learning of Social Value in Dynamic Groups.

    Science.gov (United States)

    FeldmanHall, Oriel; Dunsmoor, Joseph E; Kroes, Marijn C W; Lackovic, Sandra; Phelps, Elizabeth A

    2017-08-01

    Although humans live in societies that regularly demand engaging with multiple people simultaneously, little is known about social learning in group settings. In two experiments, we combined a Pavlovian learning framework with dyadic economic games to test whether blocking mechanisms support value-based social learning in the gain (altruistic dictators) and loss (greedy robbers) domains. Subjects first learned about an altruistic dictator, who subsequently made altruistic splits collectively with a partner. Results revealed that because the presence of the dictator already predicted the outcome, subjects did not learn to associate value with the partner. This social blocking effect was not observed in the loss domain: A kind robber's partner, who could steal all the subjects' money but stole little, acquired highly positive value-which biased subjects' subsequent behavior. These findings reveal how Pavlovian mechanisms support efficient social learning, while also demonstrating that violations of social expectations can attenuate how readily these mechanisms are recruited.

  8. Lack of association of variants previously associated with anti-TNF medication response in rheumatoid arthritis patients: results from a homogeneous Greek population.

    Directory of Open Access Journals (Sweden)

    Maria I Zervou

    Full Text Available Treatment strategies blocking tumor necrosis factor (anti-TNF have proven very successful in patients with rheumatoid arthritis (RA, showing beneficial effects in approximately 50-60% of the patients. However, a significant subset of patients does not respond to anti-TNF agents, for reasons that are still unknown. The aim of this study was to validate five single nucleotide polymorphisms (SNPs of PTPRC, CD226, AFF3, MyD88 and CHUK gene loci that have previously been reported to predict anti-TNF outcome. In addition, two markers of RA susceptibility, namely TRAF1/C5 and STAT4 were assessed, in a cohort of anti-TNF-treated RA patients, from the homogeneous Greek island of Crete, Greece. The RA patient cohort consisted of 183 patients treated with either of 3 anti-TNF biologic agents (infliximab, adalimumab and etanercept from the Clinic of Rheumatology of the University Hospital of Crete. The SNPs were genotyped by TaqMan assays or following the Restriction Fragments Length Polymorphisms (RFLPs approach. Disease activity score in 28 joints (DAS28 at baseline and after 6 months were available for all patients and analysis of good versus poor response at 6 months was performed for each SNP. None of the 7 genetic markers correlated with treatment response. We conclude that the gene polymorphisms under investigation are not strongly predictive of anti-TNF response in RA patients from Greece.

  9. Lack of association of variants previously associated with anti-TNF medication response in rheumatoid arthritis patients: results from a homogeneous Greek population.

    Science.gov (United States)

    Zervou, Maria I; Myrthianou, Efsevia; Flouri, Irene; Plant, Darren; Chlouverakis, Gregory; Castro-Giner, Francesc; Rapsomaniki, Panayiota; Barton, Anne; Boumpas, Dimitrios T; Sidiropoulos, Prodromos; Goulielmos, George N

    2013-01-01

    Treatment strategies blocking tumor necrosis factor (anti-TNF) have proven very successful in patients with rheumatoid arthritis (RA), showing beneficial effects in approximately 50-60% of the patients. However, a significant subset of patients does not respond to anti-TNF agents, for reasons that are still unknown. The aim of this study was to validate five single nucleotide polymorphisms (SNPs) of PTPRC, CD226, AFF3, MyD88 and CHUK gene loci that have previously been reported to predict anti-TNF outcome. In addition, two markers of RA susceptibility, namely TRAF1/C5 and STAT4 were assessed, in a cohort of anti-TNF-treated RA patients, from the homogeneous Greek island of Crete, Greece. The RA patient cohort consisted of 183 patients treated with either of 3 anti-TNF biologic agents (infliximab, adalimumab and etanercept) from the Clinic of Rheumatology of the University Hospital of Crete. The SNPs were genotyped by TaqMan assays or following the Restriction Fragments Length Polymorphisms (RFLPs) approach. Disease activity score in 28 joints (DAS28) at baseline and after 6 months were available for all patients and analysis of good versus poor response at 6 months was performed for each SNP. None of the 7 genetic markers correlated with treatment response. We conclude that the gene polymorphisms under investigation are not strongly predictive of anti-TNF response in RA patients from Greece.

  10. Optical implementations of associative networks with versatile adaptive learning capabilities.

    Science.gov (United States)

    Fisher, A D; Lippincott, W L; Lee, J N

    1987-12-01

    Optical associative, parallel-processing architectures are being developed using a multimodule approach, where a number of smaller, adaptive, associative modules are nonlinearly interconnected and cascaded under the guidance of a variety of organizational principles to structure larger architectures for solving specific problems. A number of novel optical implementations with versatile adaptive learning capabilities are presented for the individual associative modules, including holographic configurations and five specific electrooptic configurations. The practical issues involved in real optical architectures are analyzed, and actual laboratory optical implementations of associative modules based on Hebbian and Widrow-Hoff learning rules are discussed, including successful experimental demonstrations of their operation.

  11. Effect of intracervical anesthesia on pain associated with the insertion of the levonorgestrel-releasing intrauterine system in women without previous vaginal delivery: a RCT.

    Science.gov (United States)

    Castro, T V B; Franceschini, S A; Poli-Neto, O; Ferriani, R A; Silva de Sá, M F; Vieira, C S

    2014-11-01

    Is the pain associated with levonorgestrel-releasing intrauterine system (LNG-IUS) insertion reduced by intracervical anesthesia in women without previous vaginal birth? Intracervical anesthesia was not associated with reduced pain in women without previous vaginal birth. The pain associated with the insertion of intrauterine contraceptives (IUCs) is a limiting factor for the use of these contraceptives by some women. No prophylactic pharmacological intervention has proven efficacy in relieving pain during or after the insertion of IUCs. However, previous studies included women with previous vaginal delivery, and injectable intracervical anesthesia was not evaluated in any of these studies. This was a randomized, open, parallel-group clinical trial that evaluated 100 women without previous vaginal delivery who wished to use the LNG-IUS for the first time. These women were evaluated immediately after LNG-IUS insertion and then 2 h and 6 h later. The 100 women were randomized into two groups: (i) use of a non-steroidal anti-inflammatory drug (NSAID) (ibuprofen, 400 mg) 1 h prior to LNG-IUS insertion; or (ii) 2% lidocaine intracervical injection 5 min prior to LNG-IUS insertion. The women were evaluated immediately after LNG-IUS insertion and then 2 h and 6 h after insertion. Two pain scales were used (the visual analogue scale and the facial pain scale) in addition to assessing the ease of insertion (as rated by the provider) and the level of discomfort during the procedure (as rated by the patient). Multivariate logistic regression was performed to analyze the predictors associated with moderate/severe pain. The pain and discomfort associated with LNG-IUS insertion, and the ease of insertion of the LNG-IUS did not differ between the groups. Nulliparity was more associated with moderate/severe pain [adjusted odds ratio (OR): 3.1 (95% confidence interval (CI): 1.3-7.80]. Injectable intracervical anesthesia use reduced the risk of moderate/severe pain by 40% [adjusted

  12. Breastfeeding, previous Epstein-Barr virus infection, Enterovirus 71 infection, and rural residence are associated with the severity of hand, foot, and mouth disease.

    Science.gov (United States)

    Li, Yaping; Dang, Shuangsuo; Deng, Huiling; Wang, Wenjun; Jia, Xiaoli; Gao, Ning; Li, Mei; Wang, Jun

    2013-05-01

    Severe hand, foot, and mouth disease (HFMD) is likely to develop critical complications such as brainstem encephalitis, acute pulmonary edema, and circulatory failure, which cause child mortality during outbreaks. This study aims to investigate factors that predict the severity of HFMD. One hundred sixteen in-patient children with severe HFMD and 202 with mild HFMD were retrospectively enrolled. Potential factors were collected for each child including sex, age, residence, modes of delivery, birth weight, virus types causing HFMD, and virus exposure history. Univariate and multivariable logistic regression were used to determine which factors were associated with HFMD severity. In the univariate analysis, breastfeeding (OR 0.514, 95 % CI 0.309-0.856), rural residence (OR 1.971, 95 % CI 1.239-3.137), current Enterovirus 71 (EV71) infection (OR 2.539, 95 % CI 1.504-4.287), and previous Epstein-Barr virus (EBV) exposure (OR 3.136, 95 % CI 1.863-5.278) were each associated with the severity of HFMD. In the multivariate model, breastfeeding (OR 0.570, 95 % CI 0.332-0.980), rural residence (OR 1.973, 95 % CI 1.202-3.237), current EV71 infection (OR 2.290, 95 % CI 1.315-3.987), and previous EBV exposure (OR 2.550, 95 % CI 1.470-4.422) remained independently associated with the severity of HFMD. In conclusion, previous EBV exposure, EV71 infection, and rural residence are risk factors for severe HFMD; breastfeeding is a protective factor.

  13. Association of single nucleotide polymorphisms in candidate genes previously related to genetic variation in fertility with phenotypic measurements of reproductive function in Holstein cows.

    Science.gov (United States)

    Ortega, M Sofia; Denicol, Anna C; Cole, John B; Null, Daniel J; Taylor, Jeremy F; Schnabel, Robert D; Hansen, Peter J

    2017-05-01

    Many genetic markers related to health or production traits are not evaluated in populations independent of the discovery population or related to phenotype. Here we evaluated 68 single nucleotide polymorphisms (SNP) in candidate genes previously associated with genetic merit for fertility and production traits for association with phenotypic measurements of fertility in a population of Holstein cows that was selected based on predicted transmitting ability (PTA) for daughter pregnancy rate (DPR; high, ≥1, n = 989; low, ≤ -1.0, n = 1,285). Cows with a high PTA for DPR had higher pregnancy rate at first service, fewer services per conception, and fewer days open than cows with a low PTA for DPR. Of the 68 SNP, 11 were associated with pregnancy rate at first service, 16 with services per conception, and 19 with days open. Single nucleotide polymorphisms in 12 genes (BDH2, BSP3, CAST, CD2, CD14, FUT1, FYB, GCNT3, HSD17B7, IBSP, OCLN, and PCCB) had significant associations with 2 fertility traits, and SNP in 4 genes (CSPP1, FCER1G, PMM2, and TBC1D24) had significant associations with each of the 3 traits. Results from this experiment were compared with results from 2 earlier studies in which the SNP were associated with genetic estimates of fertility. One study involved the same animals as used here, and the other study was of an independent population of bulls. A total of 13 SNP associated with 1 or more phenotypic estimates of fertility were directionally associated with genetic estimates of fertility in the same cow population. Moreover, 14 SNP associated with reproductive phenotype were directionally associated with genetic estimates of fertility in the bull population. Nine SNP (located in BCAS, BSP3, CAST, FUT1, HSD17B7, OCLN, PCCB, PMM2, and TBC1D24) had a directional association with fertility in all 3 studies. Examination of the function of the genes with SNP associated with reproduction in more than one study indicates the importance of steroid hormones

  14. Incidental Learning of Rewarded Associations Bolsters Learning on an Associative Task

    Science.gov (United States)

    Freedberg, Michael; Schacherer, Jonathan; Hazeltine, Eliot

    2016-01-01

    Reward has been shown to change behavior as a result of incentive learning (by motivating the individual to increase their effort) and instrumental learning (by increasing the frequency of a particular behavior). However, Palminteri et al. (2011) demonstrated that reward can also improve the incidental learning of a motor skill even when…

  15. Fuzzy OLAP association rules mining-based modular reinforcement learning approach for multiagent systems.

    Science.gov (United States)

    Kaya, Mehmet; Alhajj, Reda

    2005-04-01

    Multiagent systems and data mining have recently attracted considerable attention in the field of computing. Reinforcement learning is the most commonly used learning process for multiagent systems. However, it still has some drawbacks, including modeling other learning agents present in the domain as part of the state of the environment, and some states are experienced much less than others, or some state-action pairs are never visited during the learning phase. Further, before completing the learning process, an agent cannot exhibit a certain behavior in some states that may be experienced sufficiently. In this study, we propose a novel multiagent learning approach to handle these problems. Our approach is based on utilizing the mining process for modular cooperative learning systems. It incorporates fuzziness and online analytical processing (OLAP) based mining to effectively process the information reported by agents. First, we describe a fuzzy data cube OLAP architecture which facilitates effective storage and processing of the state information reported by agents. This way, the action of the other agent, not even in the visual environment. of the agent under consideration, can simply be predicted by extracting online association rules, a well-known data mining technique, from the constructed data cube. Second, we present a new action selection model, which is also based on association rules mining. Finally, we generalize not sufficiently experienced states, by mining multilevel association rules from the proposed fuzzy data cube. Experimental results obtained on two different versions of a well-known pursuit domain show the robustness and effectiveness of the proposed fuzzy OLAP mining based modular learning approach. Finally, we tested the scalability of the approach presented in this paper and compared it with our previous work on modular-fuzzy Q-learning and ordinary Q-learning.

  16. Olfactory Perceptual Learning Requires Action of Noradrenaline in the Olfactory Bulb: Comparison with Olfactory Associative Learning

    Science.gov (United States)

    Vinera, Jennifer; Kermen, Florence; Sacquet, Joëlle; Didier, Anne; Mandairon, Nathalie; Richard, Marion

    2015-01-01

    Noradrenaline contributes to olfactory-guided behaviors but its role in olfactory learning during adulthood is poorly documented. We investigated its implication in olfactory associative and perceptual learning using local infusion of mixed a1-ß adrenergic receptor antagonist (labetalol) in the adult mouse olfactory bulb. We reported that…

  17. A cross-sectional survey assessing factors associated with reading cancer screening information: previous screening behaviour, demographics and decision-making style.

    Science.gov (United States)

    Ghanouni, Alex; Renzi, Cristina; Waller, Jo

    2017-04-18

    There is broad agreement that cancer screening invitees should know the risks and benefits of testing before deciding whether to participate. In organised screening programmes, a primary method of relaying this information is via leaflets provided at the time of invitation. Little is known about why individuals do not engage with this information. This study assessed factors associated with reading information leaflets provided by the three cancer screening programmes in England. A cross-sectional survey asked screening-eligible members of the general population in England about the following predictor variables: uptake of previous screening invitations, demographic characteristics, and 'decision-making styles' (i.e. the extent to which participants tended to make decisions in a way that was avoidant, rational, intuitive, spontaneous, or dependent). The primary outcome measures were the amount of the leaflet that participants reported having read at their most recent invitation, for any of the three programmes for which they were eligible. Associations between these outcomes and predictor variables were assessed using binary or ordinal logistic regression. After exclusions, data from 275, 309, and 556 participants were analysed in relation to the breast, cervical, and bowel screening programmes, respectively. Notable relationships included associations between regularity of screening uptake and reading (more of) the information leaflets for all programmes (e.g. odds ratio: 0.16 for participants who never/very rarely attended breast screening vs. those who always attended previously; p = .009). Higher rational decision-making scores were associated with reading more of the cervical and bowel screening leaflets (OR: 1.13, p screening uptake may also increase subsequent engagement with information. Future research could investigate how to improve engagement at initial invitations. There may also be scope to reduce barriers to accessing non-English information and

  18. Functional Specialization within the Striatum along Both the Dorsal/Ventral and Anterior/Posterior Axes during Associative Learning via Reward and Punishment

    Science.gov (United States)

    Mattfeld, Aaron T.; Gluck, Mark A.; Stark, Craig E. L.

    2011-01-01

    The goal of the present study was to elucidate the role of the human striatum in learning via reward and punishment during an associative learning task. Previous studies have identified the striatum as a critical component in the neural circuitry of reward-related learning. It remains unclear, however, under what task conditions, and to what…

  19. Observational Word Learning: Beyond Propose-But-Verify and Associative Bean Counting.

    Science.gov (United States)

    Roembke, Tanja; McMurray, Bob

    2016-04-01

    Learning new words is difficult. In any naming situation, there are multiple possible interpretations of a novel word. Recent approaches suggest that learners may solve this problem by tracking co-occurrence statistics between words and referents across multiple naming situations (e.g. Yu & Smith, 2007), overcoming the ambiguity in any one situation. Yet, there remains debate around the underlying mechanisms. We conducted two experiments in which learners acquired eight word-object mappings using cross-situational statistics while eye-movements were tracked. These addressed four unresolved questions regarding the learning mechanism. First, eye-movements during learning showed evidence that listeners maintain multiple hypotheses for a given word and bring them all to bear in the moment of naming. Second, trial-by-trial analyses of accuracy suggested that listeners accumulate continuous statistics about word/object mappings, over and above prior hypotheses they have about a word. Third, consistent, probabilistic context can impede learning, as false associations between words and highly co-occurring referents are formed. Finally, a number of factors not previously considered in prior analysis impact observational word learning: knowledge of the foils, spatial consistency of the target object, and the number of trials between presentations of the same word. This evidence suggests that observational word learning may derive from a combination of gradual statistical or associative learning mechanisms and more rapid real-time processes such as competition, mutual exclusivity and even inference or hypothesis testing.

  20. Semantic and associative factors in probability learning with words.

    Science.gov (United States)

    Schipper, L M; Hanson, B L; Taylor, G; Thorpe, J A

    1973-09-01

    Using a probability-learning technique with a single word as the cue and with the probability of a given event following this word fixed at .80, it was found (1) that neither high nor low associates to the original word and (2) that neither synonyms nor antonyms showed differential learning curves subsequent to original learning when the probability for the following event was shifted to .20. In a second study when feedback, in the form of knowledge of results, was withheld, there was a clear-cut similarity of predictions to the originally trained word and the synonyms of both high and low association value and a dissimilarity of these words to a set of antonyms of both high and low association value. Two additional studies confirmed the importance of the semantic dimension as compared with association value as traditionally measured.

  1. Machine Learning Identifies Stemness Features Associated with Oncogenic Dedifferentiation.

    Science.gov (United States)

    Malta, Tathiane M; Sokolov, Artem; Gentles, Andrew J; Burzykowski, Tomasz; Poisson, Laila; Weinstein, John N; Kamińska, Bożena; Huelsken, Joerg; Omberg, Larsson; Gevaert, Olivier; Colaprico, Antonio; Czerwińska, Patrycja; Mazurek, Sylwia; Mishra, Lopa; Heyn, Holger; Krasnitz, Alex; Godwin, Andrew K; Lazar, Alexander J; Stuart, Joshua M; Hoadley, Katherine A; Laird, Peter W; Noushmehr, Houtan; Wiznerowicz, Maciej

    2018-04-05

    Cancer progression involves the gradual loss of a differentiated phenotype and acquisition of progenitor and stem-cell-like features. Here, we provide novel stemness indices for assessing the degree of oncogenic dedifferentiation. We used an innovative one-class logistic regression (OCLR) machine-learning algorithm to extract transcriptomic and epigenetic feature sets derived from non-transformed pluripotent stem cells and their differentiated progeny. Using OCLR, we were able to identify previously undiscovered biological mechanisms associated with the dedifferentiated oncogenic state. Analyses of the tumor microenvironment revealed unanticipated correlation of cancer stemness with immune checkpoint expression and infiltrating immune cells. We found that the dedifferentiated oncogenic phenotype was generally most prominent in metastatic tumors. Application of our stemness indices to single-cell data revealed patterns of intra-tumor molecular heterogeneity. Finally, the indices allowed for the identification of novel targets and possible targeted therapies aimed at tumor differentiation. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  2. Associative learning, acquired equivalence, and flexible generalization of knowledge in mild Alzheimer disease.

    Science.gov (United States)

    Bódi, Nikoletta; Csibri, Eva; Myers, Catherine E; Gluck, Mark A; Kéri, Szabolcs

    2009-06-01

    Acquired equivalence is a phenomenon in which prior training to treat 2 stimuli as equivalent increases generalization between them. Previous studies demonstrated that the hippocampal complex might play an important role in acquired equivalence associative learning. In this study, we tested the possibility that acquired equivalence learning is a sensitive marker of mild Alzheimer disease (AD). In the associative learning test, antecedent stimuli were cartoon faces and consequent stimuli were different colored cartoon fishes. Each cartoon character had some pet fish and the task was to learn these face-fish associations using feedback provided after each decision. In the transfer phase, knowledge about face-fish pairs had to be generalized to new associations. AD patients exhibited mild impairments in the training phase, whereas they were profoundly impaired on the acquired equivalence test. Associative knowledge could not be transferred to a more flexible retrieval condition. These results suggest that acquired equivalence learning is specifically impaired in early AD, which may indicate the pathology of the hippocampal complex.

  3. Factors associated with learning outcome of BSN in a blended learning environment.

    Science.gov (United States)

    Hsu, Li-Ling; Hsieh, Suh-Ing

    2011-01-01

    This paper is a report of a study to examine the influence of demographic, learning behavior and learning performance variables on learning outcomes of baccalaureate nursing students within a blended learning environment. A cross-sectional survey was conducted using the self-structured demographic questionnaire, case analysis attitude scale (CAAS), the case analysis self-evaluation scales (CASES), the metacognition scale (MS) and blended learning satisfaction scale (BLSS) to measure learning outcomes after the blended learning course. A total of 99 senior undergraduate nursing students currently studying at a public nursing college in Taiwan were eligible to participate in the study in 2008. Data were analyzed by descriptive statistics and multiple linear regression. Univariate analysis showed significant associations between frequency of online dialogues, time spent on the internet, CAAS, and MS and scores on the ethical course. However, frequency of online dialogues, time spent on the internet, and the CAAS were significantly independent predictors for scores on the ethical course in the final model of multivariate analysis. The final model of the data analysis could account for 78% variances scores of ethical course (R(2) = 0.78 and adjusted R(2) = 0.77). It can be concluded from this study that frequency of online dialogue, time spent on internet, and the CAAS score are all useful predictors for learning outcome. In addition, blended learning was found to have contributed to learners' learning outcome by facilitating their metacognitive development and self-regulatory development. In blended learning courses, students have more responsibilities placed upon them than in traditional face-to-face learning environments. The first step of constructing a working blended learning model is to develop student-oriented teaching pedagogies that include face-to-face and online instruction, rather than just focusing on the provision of technical skills.

  4. Comfort and experience with online learning: trends over nine years and associations with knowledge

    Science.gov (United States)

    2014-01-01

    Background Some evidence suggests that attitude toward computer-based instruction is an important determinant of success in online learning. We sought to determine how comfort using computers and perceptions of prior online learning experiences have changed over the past decade, and how these associate with learning outcomes. Methods Each year from 2003–2011 we conducted a prospective trial of online learning. As part of each year’s study, we asked medicine residents about their comfort using computers and if their previous experiences with online learning were favorable. We assessed knowledge using a multiple-choice test. We used regression to analyze associations and changes over time. Results 371 internal medicine and family medicine residents participated. Neither comfort with computers nor perceptions of prior online learning experiences showed a significant change across years (p > 0.61), with mean comfort rating 3.96 (maximum 5 = very comfortable) and mean experience rating 4.42 (maximum 6 = strongly agree [favorable]). Comfort showed no significant association with knowledge scores (p = 0.39) but perceptions of prior experiences did, with a 1.56% rise in knowledge score for a 1-point rise in experience score (p = 0.02). Correlations among comfort, perceptions of prior experiences, and number of prior experiences were all small and not statistically significant. Conclusions Comfort with computers and perceptions of prior experience with online learning remained stable over nine years. Prior good experiences (but not comfort with computers) demonstrated a modest association with knowledge outcomes, suggesting that prior course satisfaction may influence subsequent learning. PMID:24985690

  5. Towards a New Study on Associative Learning in Human Fetuses: Fetal Associative Learning in Primates

    Science.gov (United States)

    Kawai, Nobuyuki

    2010-01-01

    Research has revealed that fetuses can learn from events in their environment. The most convincing evidence for fetal learning is habituation to vibroacoustic stimulation (VAS) in human fetuses and classical conditioning in rat fetuses. However, these two research areas have been independent of each other. There have been few attempts at classical…

  6. Examining rare and low-frequency genetic variants previously associated with lone or familial forms of atrial fibrillation in an electronic medical record system

    DEFF Research Database (Denmark)

    Weeke, Peter; Denny, Joshua C; Basterache, Lisa

    2015-01-01

    of European or African ancestry with electronic medical records and exome chip data to compare the frequency of AF among carriers and noncarriers of these rare variants. METHODS AND RESULTS: The exome chip included 19 of 115 rare variants, in 9 genes, previously associated with lone or familial AF. Using......BACKGROUND: Studies in individuals or small kindreds have implicated rare variants in 25 different genes in lone and familial atrial fibrillation (AF) using linkage and segregation analysis, functional characterization, and rarity in public databases. Here, we used a cohort of 20 204 patients...... validated algorithms querying a combination of clinical notes, structured billing codes, ECG reports, and procedure codes, we identified 1056 AF cases (>18 years) and 19 148 non-AF controls (>50 years) with available genotype data on the Illumina HumanExome BeadChip v.1.0 in the Vanderbilt electronic...

  7. Haplotype association between haptoglobin (Hp2 and Hp promoter SNP (A-61C may explain previous controversy of haptoglobin and malaria protection.

    Directory of Open Access Journals (Sweden)

    Sharon E Cox

    2007-04-01

    Full Text Available Malaria is one of the strongest recent selective pressures on the human genome, as evidenced by the high levels of varying haemoglobinopathies in human populations-despite the increased risk of mortality in the homozygous states. Previously, functional polymorphisms of Hp, coded by the co-dominant alleles Hp1 and Hp2, have been variously associated with several infectious diseases, including malaria susceptibility.Risk of a clinical malarial episode over the course of a malarial transmission season was assessed using active surveillance in a cohort of Gambian children aged 10-72 months. We report for the first time that the major haplotype for the A-61C mutant allele in the promoter of haptoglobin (Hp-an acute phase protein that clears haemoglobin released from haemolysis of red cells-is associated with protection from malarial infection in older children, (children aged >or=36 months, >500 parasites/ul and temperature >37.5 degrees C; OR = 0.42; [95% CI 0.24-0.73] p = 0.002 (lr test for interaction, or=36 months, p = 0.014. Protection was also observed using two other definitions, including temperature >37.5 degrees C, dipstick positive, plus clinical judgement of malaria blinded to dipstick result (all ages, OR = 0.48, [95% CI 0.30-0.78] p = 0.003; >or=36 months, OR = 0.31, [95% CI 0.15-0.62] p = 0.001. A similar level of protection was observed for the known protective genetic variant, sickle cell trait (HbAS.We propose that previous conflicting results between Hp phenotypes/genotypes and malaria susceptibility may be explained by differing prevalence of the A-61C SNP in the populations studied, which we found to be highly associated with the Hp2 allele. We report the -61C allele to be associated with decreased Hp protein levels (independent of Hp phenotype, confirming in vitro studies. Decreased Hp expression may lead to increased oxidant stress and increased red cell turnover, and facilitate the development of acquired immunity, similar to

  8. A cross-sectional survey assessing factors associated with reading cancer screening information: previous screening behaviour, demographics and decision-making style

    Directory of Open Access Journals (Sweden)

    Alex Ghanouni

    2017-04-01

    Full Text Available Abstract Background There is broad agreement that cancer screening invitees should know the risks and benefits of testing before deciding whether to participate. In organised screening programmes, a primary method of relaying this information is via leaflets provided at the time of invitation. Little is known about why individuals do not engage with this information. This study assessed factors associated with reading information leaflets provided by the three cancer screening programmes in England. Methods A cross-sectional survey asked screening-eligible members of the general population in England about the following predictor variables: uptake of previous screening invitations, demographic characteristics, and ‘decision-making styles’ (i.e. the extent to which participants tended to make decisions in a way that was avoidant, rational, intuitive, spontaneous, or dependent. The primary outcome measures were the amount of the leaflet that participants reported having read at their most recent invitation, for any of the three programmes for which they were eligible. Associations between these outcomes and predictor variables were assessed using binary or ordinal logistic regression. Results After exclusions, data from 275, 309, and 556 participants were analysed in relation to the breast, cervical, and bowel screening programmes, respectively. Notable relationships included associations between regularity of screening uptake and reading (more of the information leaflets for all programmes (e.g. odds ratio: 0.16 for participants who never/very rarely attended breast screening vs. those who always attended previously; p = .009. Higher rational decision-making scores were associated with reading more of the cervical and bowel screening leaflets (OR: 1.13, p < .0005 and OR: 1.11, p = .045, respectively. Information engagement was also higher for White British participants compared with other ethnic groups for breast (OR: 3.28, p = .008

  9. Learning to associate orientation with color in early visual areas by associative decoded fMRI neurofeedback

    OpenAIRE

    Amano, Kaoru; Shibata, Kazuhisa; Kawato, Mitsuo; Sasaki, Yuka; Watanabe, Takeo

    2016-01-01

    Associative learning is an essential brain process where the contingency of different items increases after training. Associative learning has been found to occur in many brain regions [1-4]. However, there is no clear evidence that associative learning of visual features occurs in early visual areas, although a number of studies have indicated that learning of a single visual feature (perceptual learning) involves early visual areas [5-8]. Here, via decoded functional magnetic resonance imag...

  10. Conceptual aspects: analyses law, ethical, human, technical, social factors of development ICT, e-learning and intercultural development in different countries setting out the previous new theoretical model and preliminary findings

    NARCIS (Netherlands)

    Kommers, Petrus A.M.; Smyrnova-Trybulska, Eugenia; Morze, Natalia; Issa, Tomayess; Issa, Theodora

    2015-01-01

    This paper, prepared by an international team of authors focuses on the conceptual aspects: analyses law, ethical, human, technical, social factors of ICT development, e-learning and intercultural development in different countries, setting out the previous and new theoretical model and preliminary

  11. Powerful Tests for Multi-Marker Association Analysis Using Ensemble Learning.

    Directory of Open Access Journals (Sweden)

    Badri Padhukasahasram

    Full Text Available Multi-marker approaches have received a lot of attention recently in genome wide association studies and can enhance power to detect new associations under certain conditions. Gene-, gene-set- and pathway-based association tests are increasingly being viewed as useful supplements to the more widely used single marker association analysis which have successfully uncovered numerous disease variants. A major drawback of single-marker based methods is that they do not look at the joint effects of multiple genetic variants which individually may have weak or moderate signals. Here, we describe novel tests for multi-marker association analyses that are based on phenotype predictions obtained from machine learning algorithms. Instead of assuming a linear or logistic regression model, we propose the use of ensembles of diverse machine learning algorithms for prediction. We show that phenotype predictions obtained from ensemble learning algorithms provide a new framework for multi-marker association analysis. They can be used for constructing tests for the joint association of multiple variants, adjusting for covariates and testing for the presence of interactions. To demonstrate the power and utility of this new approach, we first apply our method to simulated SNP datasets. We show that the proposed method has the correct Type-1 error rates and can be considerably more powerful than alternative approaches in some situations. Then, we apply our method to previously studied asthma-related genes in 2 independent asthma cohorts to conduct association tests.

  12. Paired Associate Learning in Chinese Children with Dyslexia

    Science.gov (United States)

    Li, Hong; Shu, Hua; McBride-Chang, Catherine; Liu, Hong Yun; Xue, Jin

    2009-01-01

    A total of 82 Chinese 11- and 12-year-olds with and without dyslexia were tested on four paired associate learning (PAL) tasks, phonological awareness, morphological awareness, rapid naming, and verbal short-term memory in three different experiments. Experiment 1 demonstrated that children with dyslexia were significantly poorer in visual-verbal…

  13. Remodeling of Hippocampal Synapses After Hippocampus-Dependent Associative Learning

    NARCIS (Netherlands)

    Geinisman, Yuri; Disterhoft, John F.; Gundersen, Hans Jørgen G.; McEchron, Matthew D.; Persina, Inna S.; Power, John M.; Zee, Eddy A. van der; West, Mark J.

    2000-01-01

    The aim of this study was to determine whether hippocampus-dependent associative learning involves changes in the number and/or structure of hippocampal synapses. A behavioral paradigm of trace eyeblink conditioning was used. Young adult rabbits were given daily 80 trial sessions to a criterion of

  14. Challenges Associated with Teaching and Learning of English ...

    African Journals Online (AJOL)

    This paper discussed the challenges which are associated with the teaching and learning of English Grammar in Nigeria secondary schools. Grammar is the spinal cord of any language and the user's mastery of it determines his competence and performance in the language. Furthermore, the factors which make teaching ...

  15. Visual paired-associate learning: in search of material-specific effects in adult patients who have undergone temporal lobectomy.

    Science.gov (United States)

    Smith, Mary Lou; Bigel, Marla; Miller, Laurie A

    2011-02-01

    The mesial temporal lobes are important for learning arbitrary associations. It has previously been demonstrated that left mesial temporal structures are involved in learning word pairs, but it is not yet known whether comparable lesions in the right temporal lobe impair visually mediated associative learning. Patients who had undergone left (n=16) or right (n=18) temporal lobectomy for relief of intractable epilepsy and healthy controls (n=13) were administered two paired-associate learning tasks assessing their learning and memory of pairs of abstract designs or pairs of symbols in unique locations. Both patient groups had deficits in learning the designs, but only the right temporal group was impaired in recognition. For the symbol location task, differences were not found in learning, but again a recognition deficit was found for the right temporal group. The findings implicate the mesial temporal structures in relational learning. They support a material-specific effect for recognition but not for learning and recall of arbitrary visual and visual-spatial associative information. Copyright © 2010 Elsevier Inc. All rights reserved.

  16. Association of previous severe low birth weight with adverse perinatal outcomes in a subsequent pregnancy among HIV-prevalent urban African women.

    Science.gov (United States)

    Smid, Marcela C; Ahmed, Yusuf; Stoner, Marie C D; Vwalika, Bellington; Stringer, Elizabeth M; Stringer, Jeffrey S A

    2017-02-01

    To evaluate the association between severity of prior low birth weight (LBW) delivery and adverse perinatal outcomes in the subsequent delivery among an HIV-prevalent urban African population. A retrospective cohort study was conducted among 41 109 women who had undergone two deliveries in Lusaka, Zambia, between February 1, 2006, and May 31, 2013. The relationship between prior LBW delivery (<2500 g) and a composite measure of adverse perinatal outcome in the second pregnancy was assessed using multivariate logistic regression. Women with prior LBW delivery (n=4259) had an increased risk of LBW in the second delivery versus those without prior LBW delivery (n=37 642). Such risk correlated with the severity of first delivery LBW. The adjusted odds ratio (AOR) was 2.89 (95% confidence interval [CI] 2.05-4.09) for a birth weight of 1000-1499 g, 3.05 (95% CI 2.42-3.86) for a birth weight of 1500-1999 g, and 2.02 (95% CI 1.81-2.27) for a birth weight of 2000-2499 g. Previous LBW delivery also increased the risk of adverse perinatal outcome, with an AOR of 1.4 (95% CI 1.2-1.7). Severe prior LBW delivery conferred substantial risk for adverse perinatal outcomes in a subsequent pregnancy. © 2016 International Federation of Gynecology and Obstetrics.

  17. Neural Pattern Similarity in the Left IFG and Fusiform Is Associated with Novel Word Learning

    Science.gov (United States)

    Qu, Jing; Qian, Liu; Chen, Chuansheng; Xue, Gui; Li, Huiling; Xie, Peng; Mei, Leilei

    2017-01-01

    Previous studies have revealed that greater neural pattern similarity across repetitions is associated with better subsequent memory. In this study, we used an artificial language training paradigm and representational similarity analysis to examine whether neural pattern similarity across repetitions before training was associated with post-training behavioral performance. Twenty-four native Chinese speakers were trained to learn a logographic artificial language for 12 days and behavioral performance was recorded using the word naming and picture naming tasks. Participants were scanned while performing a passive viewing task before training, after 4-day training and after 12-day training. Results showed that pattern similarity in the left pars opercularis (PO) and fusiform gyrus (FG) before training was negatively associated with reaction time (RT) in both word naming and picture naming tasks after training. These results suggest that neural pattern similarity is an effective neurofunctional predictor of novel word learning in addition to word memory. PMID:28878640

  18. Neural Pattern Similarity in the Left IFG and Fusiform Is Associated with Novel Word Learning

    Directory of Open Access Journals (Sweden)

    Jing Qu

    2017-08-01

    Full Text Available Previous studies have revealed that greater neural pattern similarity across repetitions is associated with better subsequent memory. In this study, we used an artificial language training paradigm and representational similarity analysis to examine whether neural pattern similarity across repetitions before training was associated with post-training behavioral performance. Twenty-four native Chinese speakers were trained to learn a logographic artificial language for 12 days and behavioral performance was recorded using the word naming and picture naming tasks. Participants were scanned while performing a passive viewing task before training, after 4-day training and after 12-day training. Results showed that pattern similarity in the left pars opercularis (PO and fusiform gyrus (FG before training was negatively associated with reaction time (RT in both word naming and picture naming tasks after training. These results suggest that neural pattern similarity is an effective neurofunctional predictor of novel word learning in addition to word memory.

  19. Analysis of current research addressing complementary use of life-cycle assessment and risk assessment for engineered nanomaterials: have lessons been learned from previous experience with chemicals?

    DEFF Research Database (Denmark)

    Grieger, Khara Deanne; Laurent, Alexis; Miseljic, Mirko

    2012-01-01

    While it is generally agreed that successful strategies to address the health and environmental impacts of engineered nanomaterials (NM) should consider the well-established frameworks for conducting life-cycle assessment (LCA) and risk assessment (RA), scientific research, and specific guidance...... on how to practically apply these methods are still very much under development. This paper evaluates how research efforts have applied LCA and RA together for NM, particularly reflecting on previous experiences with applying these methods to chemicals. Through a literature review and a separate analysis...... of research focused on applying LCA and RA together for NM, it appears that current research efforts have taken into account some key ‘‘lessons learned’’ from previous experience with chemicals while many key challenges remain for practically applying these methods to NM. We identified two main approaches...

  20. Adaptive memory: animacy effects persist in paired-associate learning.

    Science.gov (United States)

    VanArsdall, Joshua E; Nairne, James S; Pandeirada, Josefa N S; Cogdill, Mindi

    2015-01-01

    Recent evidence suggests that animate stimuli are remembered better than matched inanimate stimuli. Two experiments tested whether this animacy effect persists in paired-associate learning of foreign words. Experiment 1 randomly paired Swahili words with matched animate and inanimate English words. Participants were told simply to learn the English "translations" for a later test. Replicating earlier findings using free recall, a strong animacy advantage was found in this cued-recall task. Concerned that the effect might be due to enhanced accessibility of the individual responses (e.g., animates represent a more accessible category), Experiment 2 selected animate and inanimate English words from two more constrained categories (four-legged animals and furniture). Once again, an advantage was found for pairs using animate targets. These results argue against organisational accounts of the animacy effect and potentially have implications for foreign language vocabulary learning.

  1. Analysis of current research addressing complementary use of life-cycle assessment and risk assessment for engineered nanomaterials: have lessons been learned from previous experience with chemicals?

    International Nuclear Information System (INIS)

    Grieger, Khara D.; Laurent, Alexis; Miseljic, Mirko; Christensen, Frans; Baun, Anders; Olsen, Stig I.

    2012-01-01

    While it is generally agreed that successful strategies to address the health and environmental impacts of engineered nanomaterials (NM) should consider the well-established frameworks for conducting life-cycle assessment (LCA) and risk assessment (RA), scientific research, and specific guidance on how to practically apply these methods are still very much under development. This paper evaluates how research efforts have applied LCA and RA together for NM, particularly reflecting on previous experiences with applying these methods to chemicals. Through a literature review and a separate analysis of research focused on applying LCA and RA together for NM, it appears that current research efforts have taken into account some key “lessons learned” from previous experience with chemicals while many key challenges remain for practically applying these methods to NM. We identified two main approaches for using these methods together for NM: “LC-based RA” (traditional RA applied in a life-cycle perspective) and “RA-complemented LCA” (conventional LCA supplemented by RA in specific life-cycle steps). Hence, the latter is the only identified approach which genuinely combines LC- and RA-based methods for NM-risk research efforts to date as the former is rather a continuation of normal RA according to standard assessment procedures (e.g., REACH). Both these approaches along with recommendations for using LCA and RA together for NM are similar to those made previously for chemicals, and thus, there does not appear to be much progress made specific for NM. We have identified one issue in particular that may be specific for NM when applying LCA and RA at this time: the need to establish proper dose metrics within both methods.

  2. Circulating levels of endocannabinoids and oxylipins altered by dietary lipids in older women are likely associated with previously identified gene targets.

    Science.gov (United States)

    Watkins, Bruce A; Kim, Jeffrey; Kenny, Anne; Pedersen, Theresa L; Pappan, Kirk L; Newman, John W

    2016-11-01

    Postmenopausal women (PMW) report marginal n-3 PUFA intakes and are at risk of chronic diseases associated with the skeletal, muscular, neuroendocrine, and cardiovascular systems. How n-3 PUFA affect the amounts of endocannabinoids (ECs) and oxylipins (OLs) of metabolic and physiologic importance in PMW is not clear. Based on our recent findings that dietary n-3 PUFA alter gene targets of the EC system and lower pro-inflammatory OL we proceeded to characterize these actions in blood of PMW. Our aim was to determine levels of the ECs, OLs, and global metabolites (GM) in white PMW (75±7y), randomized in a double-masked manner, from baseline to 6mo after receiving a fish oil supplement of n-3 PUFA (720mg 20:5n3+480mg 22:6n3/d, n=20) or placebo (1.8g oleic acid/d, n=20). ECs and OLs in serum were determined by UPLC-MS/MS and GM by GC-MS and LC-MS/MS. Plasma 20:5n3 and 22:6n3 levels increased in PMW given fish oil. EC n-6 acyl-ethanolamides, arachidonate-derived diols were decreased and 20:5n3 and 22:6n3 diols, epoxides, and alcohols were increased in PMW given fish oil. GM analysis revealed that n-3 PUFA supplementation increased renal steroid hormone and proteolytic metabolite levels in PMW. Herein, we confirm that gene targets of the EC system, previously found as modifiable by n-3 PUFA result in changes in the levels of ECs and OLs in PMW. This study shows phenotypic responses (in levels) to n-3 PUFA supplementation in PMW and increases of n-3 acyl-ethanolamide and n-3-derived OL of clinical considerations in aging. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. The Adult Learning Open University Determinants (ALOUD) study: Biological and psychological factors associated with learning performance in adult distance education

    NARCIS (Netherlands)

    Neroni, Joyce; Gijselaers, Jérôme; Kirschner, Paul A.; De Groot, Renate

    2017-01-01

    Learning is crucial for everyone. The association between biological (eg, sleep, nutrition) and psychological factors (eg, test anxiety, goal orientation) and learning performance has been well established for children, adolescents and college students in traditional education. Evidence for these

  4. PREVIOUS SECOND TRIMESTER ABORTION

    African Journals Online (AJOL)

    PNLC

    PREVIOUS SECOND TRIMESTER ABORTION: A risk factor for third trimester uterine rupture in three ... for accurate diagnosis of uterine rupture. KEY WORDS: Induced second trimester abortion - Previous uterine surgery - Uterine rupture. ..... scarred uterus during second trimester misoprostol- induced labour for a missed ...

  5. Cerebellar associative sensory learning defects in five mouse autism models

    Science.gov (United States)

    Kloth, Alexander D; Badura, Aleksandra; Li, Amy; Cherskov, Adriana; Connolly, Sara G; Giovannucci, Andrea; Bangash, M Ali; Grasselli, Giorgio; Peñagarikano, Olga; Piochon, Claire; Tsai, Peter T; Geschwind, Daniel H; Hansel, Christian; Sahin, Mustafa; Takumi, Toru; Worley, Paul F; Wang, Samuel S-H

    2015-01-01

    Sensory integration difficulties have been reported in autism, but their underlying brain-circuit mechanisms are underexplored. Using five autism-related mouse models, Shank3+/ΔC, Mecp2R308/Y, Cntnap2−/−, L7-Tsc1 (L7/Pcp2Cre::Tsc1flox/+), and patDp(15q11-13)/+, we report specific perturbations in delay eyeblink conditioning, a form of associative sensory learning requiring cerebellar plasticity. By distinguishing perturbations in the probability and characteristics of learned responses, we found that probability was reduced in Cntnap2−/−, patDp(15q11-13)/+, and L7/Pcp2Cre::Tsc1flox/+, which are associated with Purkinje-cell/deep-nuclear gene expression, along with Shank3+/ΔC. Amplitudes were smaller in L7/Pcp2Cre::Tsc1flox/+ as well as Shank3+/ΔC and Mecp2R308/Y, which are associated with granule cell pathway expression. Shank3+/ΔC and Mecp2R308/Y also showed aberrant response timing and reduced Purkinje-cell dendritic spine density. Overall, our observations are potentially accounted for by defects in instructed learning in the olivocerebellar loop and response representation in the granule cell pathway. Our findings indicate that defects in associative temporal binding of sensory events are widespread in autism mouse models. DOI: http://dx.doi.org/10.7554/eLife.06085.001 PMID:26158416

  6. Implicit versus explicit associative learning and experimentally induced placebo hypoalgesia

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    Andrea L Martin-Pichora

    2011-03-01

    Full Text Available Andrea L Martin-Pichora1,2, Tsipora D. Mankovsky-Arnold3, Joel Katz11Department of Psychology, York University, Toronto, ON, Canada; 2Centre for Student Development and Counseling, Ryerson University, Toronto, ON, Canada; 3Department of Psychology, McGill University, Montreal, QC, CanadaAbstract: The present study examined whether 1 placebo hypoalgesia can be generated through implicit associative learning (ie, conditioning in the absence of conscious awareness and 2 the magnitude of placebo hypoalgesia changes when expectations about pain are made explicit. The temperature of heat pain stimuli was surreptitiously lowered during conditioning trials for the placebo cream and the magnitude of the placebo effect was assessed during a subsequent set of trials when the temperature was the same for both placebo and control conditions. To assess whether placebo hypoalgesia could be generated from an implicit tactile stimulus, a 2 × 2 design was used with direction of cream application as one factor and verbal information about which cream was being applied as the second factor. A significant placebo effect was observed when participants received verbal information about which cream was being applied but not following implicit conditioning alone. However, 87.5% of those who showed a placebo response as the result of implicit conditioning were able to accurately guess the order of cream application during the final trial, despite a lack of awareness about the sensory manipulation and low confidence in their ratings, suggesting implicit learning in some participants. In summary, implicit associative learning was evident in some participants but it was not sufficient to produce a placebo effect suggesting some level of explicit expectation or cognitive mediation may be necessary. Notably, the placebo response was abolished when expectations were made explicit, suggesting a delicate interplay between attention and expectation.Keywords: placebo hypoalgesia

  7. Explaining Research Utilization Among 4-H Faculty, Staff, and Volunteers: The Role of Self-Efficacy, Learning Goal Orientation, Training, and Previous Experience

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    Julianne Tillman

    2014-06-01

    Full Text Available An investigation of factors that facilitate the utilization of research evidence among faculty, staff, and volunteers in the 4-H Youth Development Program is presented in this paper. Participants (N= 368; 86 4-H faculty, 153 staff, and 129 volunteers represented 35 states; structural equation modeling was utilized in the analyses. Results of the path analysis explained 56% of variance in research utilization and 28% in research utilization self-efficacy. Among the factors impacting research utilization, self-efficacy played the most important role. In turn, self-efficacy for research utilization was positively influenced by participants’ learning goal orientation, frequency of 4-H training during the last 12 months, education in research-related areas, and investigative career interests. In addition, 4-H staff who were exposed to research at higher levels reported higher research utilization self-efficacy. The findings reinforce the importance of fostering research utilization self-efficacy among 4-H faculty, staff, and volunteers. Among the suggestions presented are regular 4-H training opportunities and on-going exposure to program evaluation and program improvement experiences.

  8. Rapid Plasticity in the Prefrontal Cortex during Affective Associative Learning

    Science.gov (United States)

    Rehbein, Maimu A.; Steinberg, Christian; Wessing, Ida; Pastor, María Carmen; Zwitserlood, Pienie; Keuper, Kati; Junghöfer, Markus

    2014-01-01

    MultiCS conditioning is an affective associative learning paradigm, in which affective categories consist of many similar and complex stimuli. Comparing visual processing before and after learning, recent MultiCS conditioning studies using time-sensitive magnetoencephalography (MEG) revealed enhanced activation of prefrontal cortex (PFC) regions towards emotionally paired versus neutral stimuli already during short-latency processing stages (i.e., 50 to 80 ms after stimulus onset). The present study aimed at showing that this rapid differential activation develops as a function of the acquisition and not the extinction of the emotional meaning associated with affectively paired stimuli. MEG data of a MultiCS conditioning study were analyzed with respect to rapid changes in PFC activation towards aversively (electric shock) paired and unpaired faces that occurred during the learning of stimulus-reinforcer contingencies. Analyses revealed an increased PFC activation towards paired stimuli during 50 to 80 ms already during the acquisition of contingencies, which emerged after a single pairing with the electric shock. Corresponding changes in stimulus valence could be observed in ratings of hedonic valence, although participants did not seem to be aware of contingencies. These results suggest rapid formation and access of emotional stimulus meaning in the PFC as well as a great capacity for adaptive and highly resolving learning in the brain under challenging circumstances. PMID:25333631

  9. Reconciling genetic evolution and the associative learning account of mirror neurons through data-acquisition mechanisms.

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    Lotem, Arnon; Kolodny, Oren

    2014-04-01

    An associative learning account of mirror neurons should not preclude genetic evolution of its underlying mechanisms. On the contrary, an associative learning framework for cognitive development should seek heritable variation in the learning rules and in the data-acquisition mechanisms that construct associative networks, demonstrating how small genetic modifications of associative elements can give rise to the evolution of complex cognition.

  10. Foreign language learning difficulties in Italian children: are they associated with other learning difficulties?

    Science.gov (United States)

    Ferrari, Marcella; Palladino, Paola

    2007-01-01

    A group of seventh- and eighth-grade Italian students with low achievement (LA) in learning English as a foreign language (FL) was selected and compared to a group with high achievement (HA) in FL learning. The two groups were matched for age and nonverbal intelligence. Two experiments were conducted to examine the participants' verbal and nonverbal learning skills, such as native language reading accuracy, speed and comprehension, calculation, and attention and self-regulation. Both experiments showed that the LA group seemed at risk for reading comprehension difficulties, but its reading speed and accuracy were within the average range according to Italian norms. The results also excluded the possibility that FL learning difficulties of LA participants could be associated with a deficit in calculation. Furthermore, according to teachers' ratings, children with LA appeared at risk for attention-deficit disorder (ADD). The pattern of learning difficulties of seventh- and eighth-grade participants with LA appeared to be not completely comparable with that of high school students at risk of FL learning difficulties as described in the literature.

  11. Deciphering mirror neurons: rational decision versus associative learning.

    Science.gov (United States)

    Khalil, Elias L

    2014-04-01

    The rational-decision approach is superior to the associative-learning approach of Cook et al. at explaining why mirror neurons fire or do not fire - even when the stimulus is the same. The rational-decision approach is superior because it starts with the analysis of the intention of the organism, that is, with the identification of the specific objective or goal that the organism is trying to maximize.

  12. Finding Influential Users in Social Media Using Association Rule Learning

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    Fredrik Erlandsson

    2016-04-01

    Full Text Available Influential users play an important role in online social networks since users tend to have an impact on one other. Therefore, the proposed work analyzes users and their behavior in order to identify influential users and predict user participation. Normally, the success of a social media site is dependent on the activity level of the participating users. For both online social networking sites and individual users, it is of interest to find out if a topic will be interesting or not. In this article, we propose association learning to detect relationships between users. In order to verify the findings, several experiments were executed based on social network analysis, in which the most influential users identified from association rule learning were compared to the results from Degree Centrality and Page Rank Centrality. The results clearly indicate that it is possible to identify the most influential users using association rule learning. In addition, the results also indicate a lower execution time compared to state-of-the-art methods.

  13. Associative learning during early adulthood enhances later memory retention in honeybees.

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    Andrés Arenas

    Full Text Available BACKGROUND: Cognitive experiences during the early stages of life play an important role in shaping the future behavior in mammals but also in insects, in which precocious learning can directly modify behaviors later in life depending on both the timing and the rearing environment. However, whether olfactory associative learning acquired early in the adult stage of insects affect memorizing of new learning events has not been studied yet. METHODOLOGY: Groups of adult honeybee workers that experienced an odor paired with a sucrose solution 5 to 8 days or 9 to 12 days after emergence were previously exposed to (i a rewarded experience through the offering of scented food, or (ii a non-rewarded experience with a pure volatile compound in the rearing environment. PRINCIPAL FINDINGS: Early rewarded experiences (either at 1-4 or 5-8 days of adult age enhanced retention performance in 9-12-day-conditioned bees when they were tested at 17 days of age. The highest retention levels at this age, which could not be improved with prior rewarded experiences, were found for memories established at 5-8 days of adult age. Associative memories acquired at 9-12 days of age showed a weak effect on retention for some pure pre-exposed volatile compounds; whereas the sole exposure of an odor at any younger age did not promote long-term effects on learning performance. CONCLUSIONS: The associative learning events that occurred a few days after adult emergence improved memorizing in middle-aged bees. In addition, both the timing and the nature of early sensory inputs interact to enhance retention of new learning events acquired later in life, an important matter in the social life of honeybees.

  14. Genetic dissection of memory for associative and non-associative learning in Caenorhabditis elegans.

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    Lau, H L; Timbers, T A; Mahmoud, R; Rankin, C H

    2013-03-01

    The distinction between non-associative and associative forms of learning has historically been based on the behavioral training paradigm. Through discovering the molecular mechanisms that mediate learning, we can develop a deeper understanding of the relationships between different forms of learning. Here, we genetically dissect short- and long-term memory for a non-associative form of learning, habituation and an associative form of learning, context conditioning for habituation, in the nematode Caenorhabditis elegans. In short-term chemosensory context conditioning for habituation, worms trained and tested in the presence of either a taste (sodium acetate) or smell (diacetyl) context cue show greater retention of habituation to tap stimuli when compared with animals trained and tested without a salient cue. Long-term memory for olfactory context conditioning was observed 24 h after a training procedure that does not normally induce 24 h memory. Like long-term habituation, this long-term memory was dependent on the transcription factor cyclic AMP-response element-binding protein. Worms with mutations in glr-1 [a non-N-methyl-d-aspartate (NMDA)-type glutamate receptor subunit] showed short-term but not long-term habituation or short- or long-term context conditioning. Worms with mutations in nmr-1 (an NMDA-receptor subunit) showed normal short- and long-term memory for habituation but did not show either short- or long-term context conditioning. Rescue of nmr-1 in the RIM interneurons rescued short- and long-term olfactory context conditioning leading to the hypothesis that these interneurons function to integrate information from chemosensory and mechanosensory systems for associative learning. © 2012 The Authors. Genes, Brain and Behavior © 2012 Blackwell Publishing Ltd and International Behavioural and Neural Genetics Society.

  15. Fear conditioning with film clips: a complex associative learning paradigm.

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    Kunze, Anna E; Arntz, Arnoud; Kindt, Merel

    2015-06-01

    We argue that the stimuli used in traditional fear conditioning paradigms are too simple to model the learning and unlearning of complex fear memories. We therefore developed and tested an adapted fear conditioning paradigm, specifically designed for the study of complex associative memories. Second, we explored whether manipulating the meaning and complexity of the CS-UCS association strengthened the learned fear association. In a two-day differential fear conditioning study, participants were randomly assigned to two experimental conditions. All participants were subjected to the same CSs (i.e., pictures) and UCS (i.e., 3 s film clip) during fear conditioning. However, in one of the conditions (negative-relevant context), the reinforced CS and UCS were meaningfully connected to each other by a 12 min aversive film clip presented prior to fear acquisition. Participants in the other condition (neutral context) were not able to make such meaningful connection between these stimuli, as they viewed a neutral film clip. Fear learning and unlearning were observed on fear-potentiated startle data and distress ratings within the adapted paradigm. Moreover, several group differences on these measures indicated increased UCS valence and enhanced associative memory strength in the negative-relevant context condition compared to the neutral context condition. Due to technical equipment failure, skin conductance data could not be interpreted. The fear conditioning paradigm as presented in the negative-relevant context condition holds considerable promise for the study of complex associative fear memories and therapeutic interventions for such memories. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Function's evaluation, perfusion and metabolism by positron emission tomography associated with multislice tomography (PET/CT) in patient with previous diagnosis to myocardial necrosis

    International Nuclear Information System (INIS)

    Campisi, Roxana; Aramayo, Natalia; Osorio, Amilcar

    2010-01-01

    A 64-years-old male patient with previous diagnosis of myocardial necrosis as assessed by myocardial perfusion gated single photon emission computed tomography (gSPECT) with 3-vessel-disease, left ventricular dysfunction and symptomatic by epigastric pain. The patient was referred for myocardial viability assessment by positron emission tomography (PET) to define clinical management decision. (authors) [es

  17. Perturbation of lipids and glucose metabolism associated with previous 2,4-D exposure: a cross-sectional study of NHANES III data, 1988-1994

    Science.gov (United States)

    Background Results from previous population studies showed that mortality rates from acute myocardial infarction and type-2 diabetes during the 1980s and 1990s in rural, agricultural counties of Minnesota, Montana, North and South Dakota, were higher in counties with a higher le...

  18. Differential effects of BDNF val(66)met in repetitive associative learning paradigms.

    Science.gov (United States)

    Freundlieb, Nils; Backhaus, Winifried; Brüggemann, Norbert; Gerloff, Christian; Klein, Christine; Pinnschmidt, Hans O; Hummel, Friedhelm C

    2015-09-01

    In healthy young subjects, the brain derived neurotropic factor (BDNF) val(66)met polymorphism negatively affects behavioural outcome in short-term motor cortex or hippocampus-based learning paradigms. In repetitive training paradigms over several days this effect can be overcome, in tests involving other brain areas even positive effects were found. To further specify the role of this polymorphism in cognitive processes, we used an associative vocabulary learning paradigm over four consecutive days and tested 38 young healthy subjects and 29 healthy elderly subjects. As a control paradigm, we designed a nonverbal haptic Braille letter-learning paradigm based on the same principles. Behavioural outcome was then associated with the BDNF-genotype. In the vocabulary learning task, met carrier (met/val and met/met) benefitted more from the repetitive training than val/val subjects. This was paralleled by a higher reduction of delayed answers during the course of the study, an effect that was also present in the haptic paradigm. However, in a group of healthy elderly subjects, no similar tendency was found. We conclude that the BDNF val(66)met polymorphism alters highly circumscribed answer behaviours in young healthy subjects. This might partly explain the high variability of previously published results. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Corticosterone impairs flexible adjustment of spatial navigation in an associative place-reward learning task.

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    Rusu, Silviu I; Lankelma, Jan V; Jackson, Jadin C; Van Mourik-Donga, Laura A; Joëls, Marian; Pennartz, Cyriel M A

    2018-02-14

    Cognitive challenges are often accompanied by a discharge of stress hormones, which in turn modulate multiple brain areas. Among these, the medial temporal lobe and the prefrontal cortex are critically involved in high-order cognitive functions such as learning, memory, and decision-making. Previous studies assessing the effects of corticosterone on spatial memory found an increase or a decrease in performance depending on the timing of stress hormone discharge relative to the behavioral task. Most of these studies, however, made use of aversively motivated behaviors, whereas less is known about corticosteroid effects on flexible learning during reward-driven spatial navigation. To study how corticosterone modulates flexible spatial learning, we tested rats on a place-reward association task where hormone treatment was administered immediately after a session presenting a change in reward locations. The corticosterone-treated group showed delayed learning during the initial sessions and suboptimal memory consolidation throughout testing. Repeated training on the novel reward positions improved performance and eliminated differences from the control group. We conclude that a marked increase in plasma corticosterone levels immediately after training impairs the flexible formation of new place-reward associations.

  20. Mini-review: Prediction errors, attention and associative learning.

    Science.gov (United States)

    Holland, Peter C; Schiffino, Felipe L

    2016-05-01

    Most modern theories of associative learning emphasize a critical role for prediction error (PE, the difference between received and expected events). One class of theories, exemplified by the Rescorla-Wagner (1972) model, asserts that PE determines the effectiveness of the reinforcer or unconditioned stimulus (US): surprising reinforcers are more effective than expected ones. A second class, represented by the Pearce-Hall (1980) model, argues that PE determines the associability of conditioned stimuli (CSs), the rate at which they may enter into new learning: the surprising delivery or omission of a reinforcer enhances subsequent processing of the CSs that were present when PE was induced. In this mini-review we describe evidence, mostly from our laboratory, for PE-induced changes in the associability of both CSs and USs, and the brain systems involved in the coding, storage and retrieval of these altered associability values. This evidence favors a number of modifications to behavioral models of how PE influences event processing, and suggests the involvement of widespread brain systems in animals' responses to PE. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Adolescent changes in dopamine D1 receptor expression in orbitofrontal cortex and piriform cortex accompany an associative learning deficit.

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    Anna K Garske

    Full Text Available The orbitofrontal cortex (OFC and piriform cortex are involved in encoding the predictive value of olfactory stimuli in rats, and neural responses to olfactory stimuli in these areas change as associations are learned. This experience-dependent plasticity mirrors task-related changes previously observed in mesocortical dopamine neurons, which have been implicated in learning the predictive value of cues. Although forms of associative learning can be found at all ages, cortical dopamine projections do not mature until after postnatal day 35 in the rat. We hypothesized that these changes in dopamine circuitry during the juvenile and adolescent periods would result in age-dependent differences in learning the predictive value of environmental cues. Using an odor-guided associative learning task, we found that adolescent rats learn the association between an odor and a palatable reward significantly more slowly than either juvenile or adult rats. Further, adolescent rats displayed greater distractibility during the task than either juvenile or adult rats. Using real-time quantitative PCR and immunohistochemical methods, we observed that the behavioral deficit in adolescence coincides with a significant increase in D1 dopamine receptor expression compared to juvenile rats in both the OFC and piriform cortex. Further, we found that both the slower learning and increased distractibility exhibited in adolescence could be alleviated by experience with the association task as a juvenile, or by an acute administration of a low dose of either the dopamine D1 receptor agonist SKF-38393 or the D2 receptor antagonist eticlopride. These results suggest that dopaminergic modulation of cortical function may be important for learning the predictive value of environmental stimuli, and that developmental changes in cortical dopaminergic circuitry may underlie age-related differences in associative learning.

  2. Associative Mechanisms Allow for Social Learning and Cultural Transmission of String Pulling in an Insect.

    Science.gov (United States)

    Alem, Sylvain; Perry, Clint J; Zhu, Xingfu; Loukola, Olli J; Ingraham, Thomas; Søvik, Eirik; Chittka, Lars

    2016-10-01

    Social insects make elaborate use of simple mechanisms to achieve seemingly complex behavior and may thus provide a unique resource to discover the basic cognitive elements required for culture, i.e., group-specific behaviors that spread from "innovators" to others in the group via social learning. We first explored whether bumblebees can learn a nonnatural object manipulation task by using string pulling to access a reward that was presented out of reach. Only a small minority "innovated" and solved the task spontaneously, but most bees were able to learn to pull a string when trained in a stepwise manner. In addition, naïve bees learnt the task by observing a trained demonstrator from a distance. Learning the behavior relied on a combination of simple associative mechanisms and trial-and-error learning and did not require "insight": naïve bees failed a "coiled-string experiment," in which they did not receive instant visual feedback of the target moving closer when tugging on the string. In cultural diffusion experiments, the skill spread rapidly from a single knowledgeable individual to the majority of a colony's foragers. We observed that there were several sequential sets ("generations") of learners, so that previously naïve observers could first acquire the technique by interacting with skilled individuals and, subsequently, themselves become demonstrators for the next "generation" of learners, so that the longevity of the skill in the population could outlast the lives of informed foragers. This suggests that, so long as animals have a basic toolkit of associative and motor learning processes, the key ingredients for the cultural spread of unusual skills are already in place and do not require sophisticated cognition.

  3. Laparoscopy After Previous Laparotomy

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    Zulfo Godinjak

    2006-11-01

    Full Text Available Following the abdominal surgery, extensive adhesions often occur and they can cause difficulties during laparoscopic operations. However, previous laparotomy is not considered to be a contraindication for laparoscopy. The aim of this study is to present that an insertion of Veres needle in the region of umbilicus is a safe method for creating a pneumoperitoneum for laparoscopic operations after previous laparotomy. In the last three years, we have performed 144 laparoscopic operations in patients that previously underwent one or two laparotomies. Pathology of digestive system, genital organs, Cesarean Section or abdominal war injuries were the most common causes of previouslaparotomy. During those operations or during entering into abdominal cavity we have not experienced any complications, while in 7 patients we performed conversion to laparotomy following the diagnostic laparoscopy. In all patients an insertion of Veres needle and trocar insertion in the umbilical region was performed, namely a technique of closed laparoscopy. Not even in one patient adhesions in the region of umbilicus were found, and no abdominal organs were injured.

  4. Age-related changes in contextual associative learning.

    Science.gov (United States)

    Luu, Trinh T; Pirogovsky, Eva; Gilbert, Paul E

    2008-01-01

    The hippocampus plays a critical role in processing contextual information. Although age-related changes in the hippocampus are well documented in humans, nonhuman primates, and rodents, few studies have examined contextual learning deficits in old rats. The present study investigated age-related differences in contextual associative learning in young (6 mo) and old (24 mo) rats using olfactory stimuli. Stimuli consisted of common odors mixed in sand and placed in clear plastic cups. Testing was conducted in two boxes that represented two different contexts (Context 1 and Context 2). The contexts varied based on environmental features of the box such as color (black vs. white), visual cues on the walls of the box, and flooring texture. Each rat was simultaneously presented with two cups, one filled with Odor A and one filled with Odor B in each context. In Context 1, the rat received a food reward for digging in the cup containing Odor A, but did not receive a food reward for digging in the cup containing Odor B. In Context 2, the rat was rewarded for digging in the cup containing Odor B, but did receive a reward for digging in the cup containing Odor A. Therefore, the rat learned to associate Context 1 with Odor A and Context 2 with Odor B. The rat was tested for eight days using the same odor problem throughout all days of testing. The results showed no significant difference between young and old rats on the first two days of testing; however, young rats significantly outperformed old rats on Day 3. Young rats continued to maintain superior performance compared to old rats on Days 4-8. The results suggest that aging results in functional impairments in brain regions that support memory for associations between specific cues and their respective context.

  5. Evidence for multiple processes contributing to the Perruchet effect: Response priming and associative learning.

    Science.gov (United States)

    Weidemann, Gabrielle; McAndrew, Amy; Livesey, Evan J; McLaren, Ian P L

    2016-10-01

    The Perruchet effect constitutes a robust demonstration that it is possible to dissociate conditioned responding and expectancy in a random partial reinforcement design across a variety of human associative learning paradigms. This dissociation has been interpreted as providing evidence for multiple processes supporting learning, with expectancy driven by cognitive processes that lead to a Gambler's fallacy, and the pattern of conditioned responding (CRs) the result of an associative learning process. An alternative explanation is that the pattern of CRs is the result of exposure to the unconditioned stimulus (US). In 3 human eyeblink conditioning experiments we examined these competing explanations of the Perruchet effect by employing a differential conditioning design and varying the degree to which the 2 conditioned stimuli (CS) were discriminable. Across all of these experiments there was evidence for a component of the CRs being strongly influenced by recent reinforcement, in a way that was not demonstrably influenced by manipulations of CS discriminability, which suggests a response priming mechanism contributes to the Perruchet effect. However, the complete pattern of results and an analysis of the results from previously published studies are also consistent with there being an associative contribution to the effect. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  6. A case of cutaneous squamous cell carcinoma associated with small cell carcinoma of lung developing a skin metastasis on previously irradiated area

    International Nuclear Information System (INIS)

    Kohda, Mamoru; Takei, Yoji; Ueki, Hiroaki

    1983-01-01

    Squamous cell carcinoma which occurred in the penis of a 61-year-old male patient was treated surgically and by Linac (a total of 10,400 rad). However, it was not cured. Abnormal shadows in the lung and multiple liver tumor was noted one month before death. Autopsy revealed generalized metastases of pulmonary small-cell carcinoma, and persistent squamous cell carcinoma of the penis with no metastases. Skin metastasis of lung carcinoma occurred only in the area previously irradiated. (Ueda, J.)

  7. The Relationship between Associative Learning, Transfer Generalization, and Homocysteine Levels in Mild Cognitive Impairment

    Science.gov (United States)

    Moustafa, Ahmed A.; Hewedi, Doaa H.; Eissa, Abeer M.; Myers, Catherine E.; Sadek, Hisham A.

    2012-01-01

    Previous studies have shown that high total homocysteine levels are associated with Alzheimer's disease (AD) and mild cognitive impairment (MCI). In this study, we test the relationship between cognitive function and total homocysteine levels in healthy subjects (Global Dementia Rating, CDR = 0) and individuals with MCI (CDR = 0.5). We have used a cognitive task that tests learning and generalization of rules, processes that have been previously shown to rely on the integrity of the striatal and hippocampal regions, respectively. We found that total homocysteine levels are higher in MCI individuals than in healthy controls. Unlike what we expected, we found no difference between MCI subjects and healthy controls in learning and generalization. We conducted further analysis after diving MCI subjects in two groups, depending on their Global Deterioration Scale (GDS) scores: individuals with very mild cognitive decline (vMCD, GDS = 2) and mild cognitive decline (MCD, GDS = 3). There was no difference among the two MCI and healthy control groups in learning performance. However, we found that individuals with MCD make more generalization errors than healthy controls and individuals with vMCD. We found no difference in the number of generalization errors between healthy controls and MCI individuals with vMCD. In addition, interestingly, we found that total homocysteine levels correlate positively with generalization errors, but not with learning errors. Our results are in agreement with prior results showing a link between hippocampal function, generalization performance, and total homocysteine levels. Importantly, our study is perhaps among the first to test the relationship between learning (and generalization) of rules and homocysteine levels in healthy controls and individuals with MCI. PMID:23029537

  8. Expression of c-Fos in the rat retrosplenial cortex during instrumental re-learning of appetitive bar-pressing depends on the number of stages of previous training

    Directory of Open Access Journals (Sweden)

    Olga E. Svarnik

    2013-07-01

    Full Text Available Learning is known to be accompanied by induction of c-Fos expression in cortical neurons. However, not all neurons are involved in this process. What the c-Fos expression pattern depends on is still unknown. In the present work we studied whether and to what degree previous animal experience about Task 1 influenced neuronal c-Fos expression in the retrosplenial cortex during acquisition of Task 2. Animals were progressively shaped across days to bar-press for food at the left side of the experimental chamber (Task 1. This appetitive bar-pressing behavior was shaped by nine stages ("9 stages" group, five stages ("5 stages" group or one intermediate stage ("1 stage" group. After all animals acquired the first skill and practiced it for five days, the bar and feeder on the left, familiar side of the chamber were inactivated, and the animals were allowed to learn a similar instrumental task at the opposite side of the chamber using another pair of a bar and a feeder (Task 2. The highest number of c-Fos positive neurons was found in the retrosplenial cortex of "1 stage" animals as compared to the other groups. The number of c-Fos positive neurons in "5 stages" group animals was significantly lower than in "1 stage" animals and significantly higher than in "9 stages" animals. The number of c-Fos positive neurons in the cortex of "9 stages" animals was significantly higher than in home caged control animals. At the same time, there were no significant differences between groups in such behavioral variables as the number of entrees into the feeder or bar zones during Task 2 learning. Our results suggest that c-Fos expression in the retrosplenial cortex during Task 2 acquisition was influenced by the previous learning history.

  9. Associative learning phenomena in the snail (Helix aspersa): conditioned inhibition.

    Science.gov (United States)

    Acebes, Félix; Solar, Patricia; Moris, Joaquín; Loy, Ignacio

    2012-03-01

    Two experiments using garden snails (Helix aspersa) showed conditioned inhibition using both retardation and summation tests. Conditioned inhibition is a procedure by which a stimulus becomes a predictor of the absence of a relevant event--the unconditioned stimulus (US). Typically, conditioned inhibition consists of pairings between an initially neutral conditioned stimulus, CS(2), and an effective excitatory conditioned stimulus, CS(1), in the absence of the US. Retardation and summation tests are required in order to confirm that CS(2) has acquired inhibitory properties. Conditioned inhibition has previously been found in invertebrates; however, these demonstrations did not use the retardation and summation tests required for an unambiguous demonstration of inhibition, allowing for alternative explanations. The implications of our results for the fields of comparative cognition and invertebrate physiological models of learning are discussed.

  10. The Adult Learning Open University Determinants (ALOUD) Study: Biological and Psychological Factors Associated with Learning Performance in Adult Distance Education

    Science.gov (United States)

    Neroni, Joyce; Gijselaers, Hieronymus J. M.; Kirschner, Paul A.; Groot, Renate H. M.

    2015-01-01

    Learning is crucial for everyone. The association between biological (eg, sleep, nutrition) and psychological factors (eg, test anxiety, goal orientation) and learning performance has been well established for children, adolescents and college students in traditional education. Evidence for these associations for adult distance students is lacking…

  11. tDCS Over the Motor Cortex Shows Differential Effects on Action and Object Words in Associative Word Learning in Healthy Aging

    Directory of Open Access Journals (Sweden)

    Meret Branscheidt

    2017-05-01

    Full Text Available Healthy aging is accompanied by a continuous decline in cognitive functions. For example, the ability to learn languages decreases with age, while the neurobiological underpinnings for the decline in learning abilities are not known exactly. Transcranial direct current stimulation (tDCS, in combination with appropriate experimental paradigms, is a well-established technique to investigate the mechanisms of learning. Based on previous results in young adults, we tested the suitability of an associative learning paradigm for the acquisition of action- and object-related words in a cohort of older participants. We applied tDCS to the motor cortex (MC and hypothesized an involvement of the MC in learning action-related words. To test this, a cohort of 18 healthy, older participants (mean age 71 engaged in a computer-assisted associative word-learning paradigm, while tDCS stimulation (anodal, cathodal, sham was applied to the left MC. Participants’ task performance was quantified in a randomized, cross-over experimental design. Participants successfully learned novel words, correctly translating 39.22% of the words after 1 h of training under sham stimulation. Task performance correlated with scores for declarative verbal learning and logical reasoning. Overall, tDCS did not influence associative word learning, but a specific influence was observed of cathodal tDCS on learning of action-related words during the NMDA-dependent stimulation period. Successful learning of a novel lexicon with associative learning in older participants can only be achieved when the learning procedure is changed in several aspects, relative to young subjects. Learning success showed large inter-individual variance which was dependent on non-linguistic as well as linguistic cognitive functions. Intriguingly, cathodal tDCS influenced the acquisition of action-related words in the NMDA-dependent stimulation period. However, the effect was not specific for the associative

  12. The proposed new species, cacao red vein virus, and three previously recognized badnavirus species are associated with cacao swollen shoot disease.

    Science.gov (United States)

    Chingandu, Nomatter; Kouakou, Koffie; Aka, Romain; Ameyaw, George; Gutierrez, Osman A; Herrmann, Hans-Werner; Brown, Judith K

    2017-10-19

    Cacao swollen shoot virus (CSSV), Cacao swollen shoot CD virus (CSSCDV), and Cacao swollen shoot Togo A virus (CSSTAV) cause cacao swollen shoot disease (CSSD) in West Africa. During 2000-2003, leaf and shoot-swelling symptoms and rapid tree death were observed in cacao in Cote d'Ivoire and Ghana. Molecular tests showed positive infection in only ~50-60% of symptomatic trees, suggesting the possible emergence of an unknown badnavirus. The DNA virome was determined from symptomatic cacao samples using Illumina-Hi Seq, and sequence accuracy was verified by Sanger sequencing. The resultant 14, and seven previously known, full-length badnaviral genomic and RT-RNase H sequences were analyzed by pairwise distance analysis to resolve species relationships, and by Maximum likelihood (ML) to reconstruct phylogenetic relationships. The viral coding and non-coding sequences, genome organization, and predicted conserved protein domains (CPDs) were identified and characterized at the species level. The 21 CSSD-badnaviral genomes and RT-RNase H sequences shared 70-100% and 72-100% identity, respectively. The RT-RNase H analysis predicted four species, based on an ≥80% species cutoff. The ML genome sequence tree resolved three well-supported clades, with ≥70% bootstrap, whereas, the RT-RNase H phylogeny was poorly resolved, however, both trees grouped CSSD isolates within one large clade, including the newly discovered Cacao red vein virus (CRVV) proposed species. The genome arrangement of the four species consists of four, five, or six predicted open reading frames (ORFs), and the CPDs have similar architectures. By comparison, two New World cacao-infecting badnaviruses encode four ORFs, and harbor CPDs like the West African species. Three previously recognized West African cacao-infecting badnaviral species were identified, and a fourth, previously unidentified species, CRVV, is described for the first time. The CRVV is a suspect causal agent of the rapid decline phenotype

  13. Mutations in Genes Encoding Cardiac Ion Channels Previously Associated With Sudden Infant Death Syndrome (SIDS) Are Present With High Frequency in New Exome Data

    DEFF Research Database (Denmark)

    Andreasen, Charlotte Hartig; Refsgaard, Lena; Nielsen, Jonas B

    2013-01-01

    Sudden infant death syndrome (SIDS) is the leading cause of death in the first 6 months after birth in the industrialized world. The genetic contribution to SIDS has been investigated intensively and to date, 14 cardiac channelopathy genes have been associated with SIDS. Newly published data from...

  14. Circulating levels of endocannabinoids and oxylipins altered by dietary lipids in older women are likely associated with previously identified gene targets

    Science.gov (United States)

    Postmenopausal women (PMW) report marginal n-3 PUFA intakes and are at risk of chronic diseases associated with the skeletal, muscular, and cardiovascular systems. Our investigation characterized the endocannabinoids (EC), oxylipins (OL), and global metabolites (GM) in white PMW (75 ± 7 y), randomiz...

  15. Synaptic neurotransmission depression in ventral tegmental dopamine neurons and cannabinoid-associated addictive learning.

    Science.gov (United States)

    Liu, Zhiqiang; Han, Jing; Jia, Lintao; Maillet, Jean-Christian; Bai, Guang; Xu, Lin; Jia, Zhengping; Zheng, Qiaohua; Zhang, Wandong; Monette, Robert; Merali, Zul; Zhu, Zhou; Wang, Wei; Ren, Wei; Zhang, Xia

    2010-12-20

    Drug addiction is an association of compulsive drug use with long-term associative learning/memory. Multiple forms of learning/memory are primarily subserved by activity- or experience-dependent synaptic long-term potentiation (LTP) and long-term depression (LTD). Recent studies suggest LTP expression in locally activated glutamate synapses onto dopamine neurons (local Glu-DA synapses) of the midbrain ventral tegmental area (VTA) following a single or chronic exposure to many drugs of abuse, whereas a single exposure to cannabinoid did not significantly affect synaptic plasticity at these synapses. It is unknown whether chronic exposure of cannabis (marijuana or cannabinoids), the most commonly used illicit drug worldwide, induce LTP or LTD at these synapses. More importantly, whether such alterations in VTA synaptic plasticity causatively contribute to drug addictive behavior has not previously been addressed. Here we show in rats that chronic cannabinoid exposure activates VTA cannabinoid CB1 receptors to induce transient neurotransmission depression at VTA local Glu-DA synapses through activation of NMDA receptors and subsequent endocytosis of AMPA receptor GluR2 subunits. A GluR2-derived peptide blocks cannabinoid-induced VTA synaptic depression and conditioned place preference, i.e., learning to associate drug exposure with environmental cues. These data not only provide the first evidence, to our knowledge, that NMDA receptor-dependent synaptic depression at VTA dopamine circuitry requires GluR2 endocytosis, but also suggest an essential contribution of such synaptic depression to cannabinoid-associated addictive learning, in addition to pointing to novel pharmacological strategies for the treatment of cannabis addiction.

  16. Synaptic Neurotransmission Depression in Ventral Tegmental Dopamine Neurons and Cannabinoid-Associated Addictive Learning

    Science.gov (United States)

    Liu, Zhiqiang; Han, Jing; Jia, Lintao; Maillet, Jean-Christian; Bai, Guang; Xu, Lin; Jia, Zhengping; Zheng, Qiaohua; Zhang, Wandong; Monette, Robert; Merali, Zul; Zhu, Zhou; Wang, Wei; Ren, Wei; Zhang, Xia

    2010-01-01

    Drug addiction is an association of compulsive drug use with long-term associative learning/memory. Multiple forms of learning/memory are primarily subserved by activity- or experience-dependent synaptic long-term potentiation (LTP) and long-term depression (LTD). Recent studies suggest LTP expression in locally activated glutamate synapses onto dopamine neurons (local Glu-DA synapses) of the midbrain ventral tegmental area (VTA) following a single or chronic exposure to many drugs of abuse, whereas a single exposure to cannabinoid did not significantly affect synaptic plasticity at these synapses. It is unknown whether chronic exposure of cannabis (marijuana or cannabinoids), the most commonly used illicit drug worldwide, induce LTP or LTD at these synapses. More importantly, whether such alterations in VTA synaptic plasticity causatively contribute to drug addictive behavior has not previously been addressed. Here we show in rats that chronic cannabinoid exposure activates VTA cannabinoid CB1 receptors to induce transient neurotransmission depression at VTA local Glu-DA synapses through activation of NMDA receptors and subsequent endocytosis of AMPA receptor GluR2 subunits. A GluR2-derived peptide blocks cannabinoid-induced VTA synaptic depression and conditioned place preference, i.e., learning to associate drug exposure with environmental cues. These data not only provide the first evidence, to our knowledge, that NMDA receptor-dependent synaptic depression at VTA dopamine circuitry requires GluR2 endocytosis, but also suggest an essential contribution of such synaptic depression to cannabinoid-associated addictive learning, in addition to pointing to novel pharmacological strategies for the treatment of cannabis addiction. PMID:21187978

  17. Synaptic neurotransmission depression in ventral tegmental dopamine neurons and cannabinoid-associated addictive learning.

    Directory of Open Access Journals (Sweden)

    Zhiqiang Liu

    2010-12-01

    Full Text Available Drug addiction is an association of compulsive drug use with long-term associative learning/memory. Multiple forms of learning/memory are primarily subserved by activity- or experience-dependent synaptic long-term potentiation (LTP and long-term depression (LTD. Recent studies suggest LTP expression in locally activated glutamate synapses onto dopamine neurons (local Glu-DA synapses of the midbrain ventral tegmental area (VTA following a single or chronic exposure to many drugs of abuse, whereas a single exposure to cannabinoid did not significantly affect synaptic plasticity at these synapses. It is unknown whether chronic exposure of cannabis (marijuana or cannabinoids, the most commonly used illicit drug worldwide, induce LTP or LTD at these synapses. More importantly, whether such alterations in VTA synaptic plasticity causatively contribute to drug addictive behavior has not previously been addressed. Here we show in rats that chronic cannabinoid exposure activates VTA cannabinoid CB1 receptors to induce transient neurotransmission depression at VTA local Glu-DA synapses through activation of NMDA receptors and subsequent endocytosis of AMPA receptor GluR2 subunits. A GluR2-derived peptide blocks cannabinoid-induced VTA synaptic depression and conditioned place preference, i.e., learning to associate drug exposure with environmental cues. These data not only provide the first evidence, to our knowledge, that NMDA receptor-dependent synaptic depression at VTA dopamine circuitry requires GluR2 endocytosis, but also suggest an essential contribution of such synaptic depression to cannabinoid-associated addictive learning, in addition to pointing to novel pharmacological strategies for the treatment of cannabis addiction.

  18. Pavlovian reward learning elicits attentional capture by reward-associated stimuli.

    Science.gov (United States)

    Mine, Chisato; Saiki, Jun

    2018-03-14

    Feature-reward association elicits value-driven attentional capture (VDAC) regardless of the task relevance of associated features. What are the necessary conditions for feature-reward associations in VDAC? Recent studies claim that VDAC is based on Pavlovian conditioning. In this study, we manipulated the temporal relationships among feature, response, and reward in reward learning to elucidate the necessary components of VDAC. We presented reward-associated features in a variety of locations in a flanker task to form a color-reward association (training phase) and then tested VDAC in a subsequent visual search task (test phase). In Experiment 1, we showed reward-associated features in a task display requiring response selection and observed VDAC, consistent with most previous studies. In Experiment 2, features presented at a fixation display before a task display also induced VDAC. Moreover, in Experiment 3, we reduced the time interval between features and rewards so that features appeared after a task display and we obtained marginally significant VDAC. However, no VDAC was observed when features and rewards were simultaneously presented in a feedback display in Experiments 4 and 5, suggesting that a direct association between feature and reward is not sufficient for VDAC. These results are in favor of the idea that response selection does not mediate feature-reward association in VDAC. Moreover, the evidence suggests that the time interval of feature and reward is flexible with some restriction in the learning of feature-reward association. The present study supports the hypothesis that theories of Pavlovian conditioning can account for feature-reward association in VDAC.

  19. Prediction and uncertainty in associative learning: examining controlled and automatic components of learned attentional biases.

    Science.gov (United States)

    Luque, David; Vadillo, Miguel A; Le Pelley, Mike E; Beesley, Tom

    2017-08-01

    It has been suggested that attention is guided by two factors that operate during associative learning: a predictiveness principle, by which attention is allocated to the best predictors of outcomes, and an uncertainty principle, by which attention is allocated to learn about the less known features of the environment. Recent studies have shown that predictiveness-driven attention can operate rapidly and in an automatic way to exploit known relationships. The corresponding characteristics of uncertainty-driven attention, on the other hand, remain unexplored. In two experiments we examined whether both predictiveness and uncertainty modulate attentional processing in an adaptation of the dot probe task. This task provides a measure of automatic orientation to cues during associative learning. The stimulus onset asynchrony of the probe display was manipulated in order to explore temporal characteristics of predictiveness- and uncertainty-driven attentional effects. Results showed that the predictive status of cues determined selective attention, with faster attentional capture to predictive than to non-predictive cues. In contrast, the level of uncertainty slowed down responses to the probe regardless of the predictive status of the cues. Both predictiveness- and uncertainty-driven attentional effects were very rapid (at 250 ms from cue onset) and were automatically activated.

  20. Low-dose aspirin-associated upper gastric and duodenal ulcers in Japanese patients with no previous history of peptic ulcers

    OpenAIRE

    Kawamura, Naohiko; Ito, Yoshitsugu; Sasaki, Makoto; Iida, Akihito; Mizuno, Mari; Ogasawara, Naotaka; Funaki, Yasushi; Kasugai, Kunio

    2013-01-01

    Background Long-term administration of low-dose aspirin (LDA) is associated with a greater risk of adverse events, including gastroduodenal ulcers. The purpose of this study was to identify the risk factors for and assess the role of medication use in the development of peptic ulcer disease in Japanese patients with no history of peptic ulcers. Methods Consecutive outpatients receiving LDA (75?mg/day) who underwent esophagogastroduodenoscopy between January and December 2010 were enrolled. Cl...

  1. Word, nonword and visual paired associate learning in Dutch dyslexic children

    NARCIS (Netherlands)

    Messbauer, V.C.S.; de Jong, P.F.

    2003-01-01

    Verbal and non-verbal learning were investigated in 21 8-11-year-old dyslexic children and chronological-age controls, and in 21 7-9-year-old reading-age controls. Tasks involved the paired associate learning of words, nonwords, or symbols with pictures. Both learning and retention of associations

  2. Neural compensation in adulthood following very preterm birth demonstrated during a visual paired associates learning task.

    Science.gov (United States)

    Brittain, Philip J; Froudist Walsh, Sean; Nam, Kie-Woo; Giampietro, Vincent; Karolis, Vyacheslav; Murray, Robin M; Bhattacharyya, Sagnik; Kalpakidou, Anastasia; Nosarti, Chiara

    2014-01-01

    Very preterm birth (VPT; brain insult; however, adaptive neuroplastic processes may subsequently occur in the developing preterm brain which ameliorate, to an extent, the potential sequelae of altered neurophysiology. Here, we used functional magnetic resonance imaging (fMRI) to compare neuronal activation in 24 VPT individuals and 22 controls (CT) in young adulthood during a learning task consisting of the encoding and subsequent recognition of repeated visual paired associates. Structural MRI data were also collected and analysed in order to explore possible structure-function associations. Whilst the two groups did not differ in their learning ability, as demonstrated by their capacity to recognize previously-seen and previously-unseen visual pairs, between-group differences in linear patterns of Blood Oxygenation Level Dependant (BOLD) activity were observed across the four repeated blocks of the task for both the encoding and recognition conditions, suggesting that the way learning takes place differs between the two groups. During encoding, significant between-group differences in patterns of BOLD activity were seen in clusters centred on the cerebellum, the anterior cingulate gyrus, the midbrain/substantia nigra, medial temporal (including parahippocampal) gyrus and inferior and superior frontal gyri. During the recognition condition, significant between-group differences in patterns of BOLD activity were seen in clusters centred on the claustrum and the posterior cerebellum. Structural analysis revealed smaller grey matter volume in right middle temporal gyrus in VPT individuals compared to controls, however volume in this region was not significantly associated with functional activation. These results demonstrate that although cognitive task performance between VPT individuals and controls may be comparable on certain measures, differences in BOLD signal may also be evident, some of which could represent compensatory neural processes following VPT

  3. Low-dose aspirin-associated upper gastric and duodenal ulcers in Japanese patients with no previous history of peptic ulcers.

    Science.gov (United States)

    Kawamura, Naohiko; Ito, Yoshitsugu; Sasaki, Makoto; Iida, Akihito; Mizuno, Mari; Ogasawara, Naotaka; Funaki, Yasushi; Kasugai, Kunio

    2013-11-12

    Long-term administration of low-dose aspirin (LDA) is associated with a greater risk of adverse events, including gastroduodenal ulcers. The purpose of this study was to identify the risk factors for and assess the role of medication use in the development of peptic ulcer disease in Japanese patients with no history of peptic ulcers. Consecutive outpatients receiving LDA (75 mg/day) who underwent esophagogastroduodenoscopy between January and December 2010 were enrolled. Clinical parameters, peptic ulcer history, concomitant drugs, the presence of Helicobacter pylori infection, reason for endoscopy, and endoscopic findings were analysed. Of 226 total patients, 14 (6.2%) were endoscopically diagnosed with peptic ulcer. Age, sex, current smoking status, current alcohol consumption, endoscopic gastric mucosal atrophy, and abdominal symptoms were not significantly associated with peptic ulcers. Diabetes mellitus was more frequent (42.9% vs. 16.5%; P = 0.024) in patients with peptic ulcers than in those without peptic ulcers. Using multiple logistic regression analysis, co-treatment with anticoagulants or proton pump inhibitors (PPIs) was significantly associated with increased and decreased risk for peptic ulcer, respectively (odds ratio [OR], 5.88; 95% confidence interval [CI], 1.19 - 28.99; P = 0.03 and OR, 0.13; 95% CI, 0.02 - 0.73; P = 0.02, respectively). Co-treatment with additional antiplatelet agents, H2-receptor antagonists, angiotensin II Type 1 receptor blockers, angiotensin-converting enzyme inhibitor, 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor, or nonsteroidal anti-inflammatory drugs was not associated with peptic ulcer development. The use of PPIs reduces the risk of developing gastric or duodenal ulcers in Japanese patients taking LDA without pre-existing gastroduodenal ulcers. However, this risk is significantly increased in both patients ingesting anticoagulants and patients with diabetes. These results may help identify

  4. Perception of collaborative learning in associate degree students in Hong Kong.

    Science.gov (United States)

    Shek, Daniel T L; Shek, Moses M W

    2013-01-01

    Although collaborative learning has been widely researched in Western contexts, no study has been carried out to understand how associate degree students look at collaborative learning in Hong Kong. In this study, perceptions of and attitudes to collaborative learning among associate degree students were studied. A total of 44 associate degree students completed an online questionnaire including measures of perceived benefits and attitudes to collaborative learning, and social-emotional competence. Results showed that there were no significant differences between male and female students on perceived benefits of and attitudes towards collaborative learning. Social-emotional competence was related to perceived benefits of and attitudes to collaborative learning. Attitudes were also related to perceived benefits of collaborative learning. This paper is the first known study looking at the relationships among perceived benefits and attitudes to collaborative learning and social-emotional competence in Chinese associate degree students in different Chinese contexts.

  5. The power of associative learning and the ontogeny of optimal behaviour

    Science.gov (United States)

    Enquist, Magnus; Lind, Johan

    2016-01-01

    Behaving efficiently (optimally or near-optimally) is central to animals' adaptation to their environment. Much evolutionary biology assumes, implicitly or explicitly, that optimal behavioural strategies are genetically inherited, yet the behaviour of many animals depends crucially on learning. The question of how learning contributes to optimal behaviour is largely open. Here we propose an associative learning model that can learn optimal behaviour in a wide variety of ecologically relevant circumstances. The model learns through chaining, a term introduced by Skinner to indicate learning of behaviour sequences by linking together shorter sequences or single behaviours. Our model formalizes the concept of conditioned reinforcement (the learning process that underlies chaining) and is closely related to optimization algorithms from machine learning. Our analysis dispels the common belief that associative learning is too limited to produce ‘intelligent’ behaviour such as tool use, social learning, self-control or expectations of the future. Furthermore, the model readily accounts for both instinctual and learned aspects of behaviour, clarifying how genetic evolution and individual learning complement each other, and bridging a long-standing divide between ethology and psychology. We conclude that associative learning, supported by genetic predispositions and including the oft-neglected phenomenon of conditioned reinforcement, may suffice to explain the ontogeny of optimal behaviour in most, if not all, non-human animals. Our results establish associative learning as a more powerful optimizing mechanism than acknowledged by current opinion. PMID:28018662

  6. Advanced Parkinson’s disease effect on goal-directed and habitual processes involved in visuomotor associative learning

    Directory of Open Access Journals (Sweden)

    Fadila eHadj-Bouziane

    2013-01-01

    Full Text Available The present behavioral study readdresses the question of habit learning in Parkinson's disease. Patients were early onset, non-demented, dopa-responsive, candidates for surgical treatment, similar to those we found earlier as suffering greater dopamine depletion in the putamen than in the caudate nucleus. The task was the same conditional associative learning task as that used previously in monkeys and healthy humans to unveil the striatum involvement in habit learning. Sixteen patients and 20 age- and education-matched healthy control subjects learned sets of 3 visuo-motor associations between complex patterns and joystick displacements during two testing sessions separated by a few hours. We distinguished errors preceding versus following the first correct response to compare patients' performance during the earliest phase of learning dominated by goal-directed actions with that observed later on, when responses start to become habitual. The disease significantly retarded both learning phases, especially in patients under sixty years of age. However, only the late phase deficit was disease severity-dependent and persisted on the second testing session. These findings provide the first corroboration in Parkinson patients of two ideas well-established in the animal literature. The first is the idea that associating visual stimuli to motor acts is a form of habit learning that engages the striatum. It is confirmed here by the global impairment in visuo-motor learning induced by Parkinson's disease. The second idea is that goal-directed behaviors are predominantly caudate-dependent whereas habitual responses are primarily putamen-dependent. At the advanced Parkinson's disease stages tested here, dopamine depletion is greater in the putamen than in the caudate nucleus. Accordingly, the late phase of learning corresponding to the emergence of habitual responses was more vulnerable to the disease than the early phase dominated by goal

  7. Position of the American Dietetic Association: dietetics professionals can implement practices to conserve natural resources and protect the environment. (Previously titled "natural resource conservation and waste management").

    Science.gov (United States)

    2001-10-01

    It is the position of the American Dietetic Association to encourage environmentally responsible practices that conserve natural resources, minimize the quantity of waste that is generated, and have the least adverse affect on the health of all living organisms and the environment. All components of the food system, from farmer to consumer, are affected by the availability and cost of energy and the availability and quality of water. Outdoor and indoor air quality significantly impacts the health of all living organisms. Decisions that dietetics professionals make as practitioners and consumers can affect the quantity and type of solid waste generated. The demand for natural resources should be evaluated when selecting the most cost-effective, environmentally sensitive approach to the management of solid waste. Special precautions are needed when using and disposing of hazardous and medical waste to protect the safety of our clients and employees. This position paper provides information and resources for dietetics professionals for addressing the complexity of the environmental issue presented. Conservation strategies are identified that dietetics professionals can use in their worksites and at home. These conservation practices may reduce cost and decrease the environmental impact we have on our communities and the world.

  8. Molecular diagnosis of a previously unreported predator-prey association in coffee: Karnyothrips flavipes Jones (Thysanoptera: Phlaeothripidae) predation on the coffee berry borer

    Science.gov (United States)

    Jaramillo, Juliana; Chapman, Eric G.; Vega, Fernando E.; Harwood, James D.

    2010-03-01

    The coffee berry borer, Hypothenemus hampei, is the most important pest of coffee throughout the world, causing losses estimated at US 500 million/year. The thrips Karnyothrips flavipes was observed for the first time feeding on immature stages of H. hampei in April 2008 from samples collected in the Kisii area of Western Kenya. Since the trophic interactions between H. hampei and K. flavipes are carried out entirely within the coffee berry, and because thrips feed by liquid ingestion, we used molecular gut-content analysis to confirm the potential role of K. flavipes as a predator of H. hampei in an organic coffee production system. Species-specific COI primers designed for H. hampei were shown to have a high degree of specificity for H. hampei DNA and did not produce any PCR product from DNA templates of the other insects associated with the coffee agroecosystems. In total, 3,327 K. flavipes emerged from 17,792 H. hampei-infested berries collected from the field between April and September 2008. Throughout the season, 8.3% of K. flavipes tested positive for H. hampei DNA, although at times this figure approached 50%. Prey availability was significantly correlated with prey consumption, thus indicating the potential impact on H. hampei populations.

  9. [The association between iron deficiency and learning disorders in preschoolers].

    Science.gov (United States)

    Gutiérrez Sigler, D; Colomer Revuelta, J; Barona, C; Momparler, P; Colomer Revuelta, C

    1992-01-01

    With the aim preventing future problems of underachievement at school, we studied the possible relationship between learning difficulties and iron deficiency in nursery-school children. To do this, we determined the prevalence of iron deficiency and the prevalence or learning difficulties in the different areas of mental development in a sample of 136 nursery school children coming from the Alaquàs public school (Valencia), aged between four and five years. Their nutritional state and ferric state, socioeconomic and cultural level, and psychomotor development were evaluated. All the children were in a good nutritional state, coming from homogeneous families as regards their socio-cultural level and being divided into two groups as regards their economic situation. The iron deficiency prevalence was 17.6% in stage I (ferritina sérica < 12 ng/l) and 22.8% in stage III (anemia ferropénica). The coefficient for overall development was 85.95, the lowest marks being in the speech area. A positive association (prevalence ratio = 2; IC 95% = 1.1-8.3) between iron deficiency in its III stage and changes in the specific area of analysis and synthesis.

  10. Analysis of 24-h Rhythm in Ventricular Repolarization Identifies QT Diurnality As a Novel Clinical Parameter Associated with Previous Ventricular Arrhythmias in Heart Failure Patients

    Directory of Open Access Journals (Sweden)

    Bastiaan C. Du Pre

    2017-08-01

    Full Text Available Introduction: Cardiac repolarization abnormalities are among the major causes of ventricular arrhythmias and sudden cardiac death. In humans, cardiac repolarization duration has a 24-h rhythm. Animal studies show that this rhythm is regulated by 24-h rhythms in ion channel function and that disruption of this rhythm leads to ventricular arrhythmias. We hypothesized that 24-h rhythms in QT duration can be used as a predictor for sudden cardiac death and are associated with ventricular arrhythmias. Secondly, we assessed a possible mechanistic explanation by studying the putative role of hERG channel dysfunction.Materials and Methods: In 2 retrospective studies, measures of the 24-h variation in the QT and QTc intervals (QT and QTc diurnality, QTd and QTcd, respectively have been derived from Holter analyses and compared between groups: 1 39 post-infarct patients with systolic heart failure (CHF: EF < 35%, of which 14 with, and 25 without a history of ventricular arrhythmias and 2 five patients with proven (LQTS2 and 16 with potential (Sotalol-induced hERG channel dysfunction vs. 22 controls.Results: QTd was two-fold higher in CHF patients with a history of ventricular arrhythmias (38 ± 15 ms compared to CHF patients without VT (16 ± 9 ms, p = 0.001. QTd was significantly increased in LQT2 patients (43 ± 24 ms or those treated with Sotalol (30 ± 10 ms compared to controls (21 ± 8 ms, p < 0.05 for both.Discussion: QT diurnality presents a novel clinical parameter of repolarization that can be derived from Holter registrations and may be useful for identification of patients at risk for ventricular arrhythmias.

  11. Clinical and Economic Outcomes Associated With the Timing of Initiation of Basal Insulin in Patients With Type 2 Diabetes Mellitus Previously Treated With Oral Antidiabetes Drugs.

    Science.gov (United States)

    Levin, Philip; Zhou, Steve; Durden, Emily; Farr, Amanda M; Gill, Jasvinder; Wei, Wenhui

    2016-01-01

    In patients with type 2 diabetes mellitus (T2DM) not achieving glycemic targets using oral antidiabetes drugs (OADs), studies suggest that timely insulin initiation has clinical benefits. Insulin initiation at the early versus late stage of disease progression has not been explored in detail. This retrospective database analysis investigated clinical and economic outcomes associated with the timing of insulin initiation in patients with T2DM treated with ≥1 OAD in a real-world US setting. This study linked data from the Truven Health MarketScan(®) Commercial database, Medicare Supplemental database, and Quintiles Electronic Medical Records database. A total of 1830 patients with T2DM were included. Patients were grouped according to their OAD use before basal insulin initiation (1, 2, or ≥3 OADs) as a proxy for the timing of insulin initiation. Clinical and economic outcomes were evaluated over 1 year of follow-up. During follow-up the 1 OAD group, compared with the 2 and ≥3 OADs groups, had a greater reduction in glycosylated hemoglobin A1c (-1.7% vs -1.0% vs -0.9%, respectively; P health care costs ($21,167 vs $21,060 vs $20,133, respectively). This study shows that early insulin initiation (represented by the 1 OAD group) may be clinically beneficial to patients with T2DM not controlled with OADs, without adding to costs. This supports the call for timely initiation of individualized insulin therapy in this population. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  12. Solution of the comparator theory of associative learning.

    Science.gov (United States)

    Ghirlanda, Stefano; Ibadullayev, Ismet

    2015-04-01

    We derive an analytical solution of the comparator theory of associative learning, as formalized by Stout and Miller (2007). The solution enables us to calculate exactly the predicted responding to stimuli in any experimental design and for any choice of model parameters. We illustrate its utility by calculating the predictions of comparator theory in some paradigmatic designs: acquisition of conditioned responses, compound conditioning, blocking, unovershadowing, and backward blocking. We consider several versions of the theory: first-order comparator theory (close to the original ideas of Miller & Matzel, 1988), second-order comparator theory (Denniston, Savastano, & Miller, 2001), and sometimes-competing retrieval (Stout & Miller, 2007). We show that all versions of comparator theory make a number of surprising predictions, some of which appear hard to reconcile with empirical data. Our solution paves the way for a fuller understanding of the theory and for its empirical evaluation. (c) 2015 APA, all rights reserved).

  13. Honeybee associative learning performance and metabolic stress resilience are positively associated.

    Directory of Open Access Journals (Sweden)

    Gro V Amdam

    2010-03-01

    Full Text Available Social-environmental influences can affect animal cognition and health. Also, human socio-economic status is a covariate factor connecting psychometric test-performance (a measure of cognitive ability, educational achievement, lifetime health, and survival. The complimentary hypothesis, that mechanisms in physiology can explain some covariance between the same traits, is disputed. Possible mechanisms involve metabolic biology affecting integrity and stability of physiological systems during development and ageing. Knowledge of these relationships is incomplete, and underlying processes are challenging to reveal in people. Model animals, however, can provide insights into connections between metabolic biology and physiological stability that may aid efforts to reduce human health and longevity disparities.We document a positive correlation between a measure of associative learning performance and the metabolic stress resilience of honeybees. This relationship is independent of social factors, and may provide basic insights into how central nervous system (CNS function and metabolic biology can be associated. Controlling for social environment, age, and learning motivation in each bee, we establish that learning in Pavlovian conditioning to an odour is positively correlated with individual survival time in hyperoxia. Hyperoxia induces oxidative metabolic damage, and provides a measure of metabolic stress resistance that is often related to overall lifespan in laboratory animals. The positive relationship between Pavlovian learning ability and stress resilience in the bee is not equally established in other model organisms so far, and contrasts with a genetic cost of improved associative learning found in Drosophila melanogaster.Similarities in the performances of different animals need not reflect common functional principles. A correlation of honeybee Pavlovian learning and metabolic stress resilience, thereby, is not evidence of a shared biology

  14. Learning to Associate Orientation with Color in Early Visual Areas by Associative Decoded fMRI Neurofeedback.

    Science.gov (United States)

    Amano, Kaoru; Shibata, Kazuhisa; Kawato, Mitsuo; Sasaki, Yuka; Watanabe, Takeo

    2016-07-25

    Associative learning is an essential brain process where the contingency of different items increases after training. Associative learning has been found to occur in many brain regions [1-4]. However, there is no clear evidence that associative learning of visual features occurs in early visual areas, although a number of studies have indicated that learning of a single visual feature (perceptual learning) involves early visual areas [5-8]. Here, via decoded fMRI neurofeedback termed "DecNef" [9], we tested whether associative learning of orientation and color can be created in early visual areas. During 3 days of training, DecNef induced fMRI signal patterns that corresponded to a specific target color (red) mostly in early visual areas while a vertical achromatic grating was physically presented to participants. As a result, participants came to perceive "red" significantly more frequently than "green" in an achromatic vertical grating. This effect was also observed 3-5 months after the training. These results suggest that long-term associative learning of two different visual features such as orientation and color was created, most likely in early visual areas. This newly extended technique that induces associative learning is called "A-DecNef," and it may be used as an important tool for understanding and modifying brain functions because associations are fundamental and ubiquitous functions in the brain. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Neural compensation in adulthood following very preterm birth demonstrated during a visual paired associates learning task

    Directory of Open Access Journals (Sweden)

    Philip J. Brittain

    2014-01-01

    Full Text Available Very preterm birth (VPT; < 33 weeks of gestation is associated with an increased risk of learning disability, which contributes to more VPT-born children repeating grades and underachieving in school. Learning problems associated with VPT birth may be caused by pathophysiological alterations in neurodevelopment resulting from perinatal brain insult; however, adaptive neuroplastic processes may subsequently occur in the developing preterm brain which ameliorate, to an extent, the potential sequelae of altered neurophysiology. Here, we used functional magnetic resonance imaging (fMRI to compare neuronal activation in 24 VPT individuals and 22 controls (CT in young adulthood during a learning task consisting of the encoding and subsequent recognition of repeated visual paired associates. Structural MRI data were also collected and analysed in order to explore possible structure-function associations. Whilst the two groups did not differ in their learning ability, as demonstrated by their capacity to recognize previously-seen and previously–unseen visual pairs, between-group differences in linear patterns of Blood Oxygenation Level Dependant (BOLD activity were observed across the four repeated blocks of the task for both the encoding and recognition conditions, suggesting that the way learning takes place differs between the two groups. During encoding, significant between-group differences in patterns of BOLD activity were seen in clusters centred on the cerebellum, the anterior cingulate gyrus, the midbrain/substantia nigra, medial temporal (including parahippocampal gyrus and inferior and superior frontal gyri. During the recognition condition, significant between-group differences in patterns of BOLD activity were seen in clusters centred on the claustrum and the posterior cerebellum. Structural analysis revealed smaller grey matter volume in right middle temporal gyrus in VPT individuals compared to controls, however volume in this region

  16. Protein kinase C activation induces conductance changes in Hermissenda photoreceptors like those seen in associative learning.

    Science.gov (United States)

    Farley, J; Auerbach, S

    Phosphorylation of ion channels has been suggested as one molecular mechanism responsible for learning-produced long-term changes in neuronal excitability. Persistent training-produced changes in two distinct K+ currents (IA (ref. 2), IK-Ca (refs 3,4)) and a voltage-dependent calcium current (ICa; refs 3,4) have previously been shown to occur in type B photoreceptors of Hermissenda, as a result of associative learning. But the identity of the phosphorylation pathway(s) responsible for these changes has not as yet been determined. Injections of cyclic AMP-dependent protein kinase reduce a K+ current (IK) in B cells which is different from those changed by training, but fails to reduce IA and IK-Ca. Phosphorylase b kinase (an exogenous calcium/calmodulin-dependent kinase) reduces IA, but whether IK-Ca and ICa are changed in the manner of associative training is not yet known. Another protein kinase present in high concentrations in both mammalian brain and molluscan nervous systems is protein kinase C, which is both calcium- and phospholipid-sensitive. We now present evidence that activation of protein kinase C by the tumour promoter phorbol ester (PDB) and intracellular injection of the enzyme induce conductance changes similar to those caused by associative training in Hermissenda B cells (that is a reduction of IA and IK-Ca, and enhancement of ICa). These results represent the first direct demonstration that protein kinase C affects membrane K+ ion conductance mechanisms.

  17. Learning during Processing: Word Learning Doesn't Wait for Word Recognition to Finish

    Science.gov (United States)

    Apfelbaum, Keith S.; McMurray, Bob

    2017-01-01

    Previous research on associative learning has uncovered detailed aspects of the process, including what types of things are learned, how they are learned, and where in the brain such learning occurs. However, perceptual processes, such as stimulus recognition and identification, take time to unfold. Previous studies of learning have not addressed…

  18. Effect of Phonetic Association on Learning Vocabulary in Foreign Language

    Science.gov (United States)

    Bozavli, Ebubekir

    2017-01-01

    Word is one of the most important components of a natural language. Speech is meaningful because of the meanings of words. Vocabulary acquired in one's mother tongue is learned consciously in a foreign language in non-native settings. Learning vocabulary in a system based on grammar is generally neglected or learned in conventional ways. This…

  19. Challenges Associated with Teaching and Learning of English ...

    African Journals Online (AJOL)

    Nekky Umera

    structures. Challenges in the Teaching and Learning of Grammar. Learners' errors and deviant forms in the use of English are a major challenge in the teaching and learning of English in Nigerian. Secondary Schools. However, Kisparsky (1972) Akinbode (2006) have classified errors in second language learning into two.

  20. Group social rank is associated with performance on a spatial learning task.

    Science.gov (United States)

    Langley, Ellis J G; van Horik, Jayden O; Whiteside, Mark A; Madden, Joah R

    2018-02-01

    Dominant individuals differ from subordinates in their performances on cognitive tasks across a suite of taxa. Previous studies often only consider dyadic relationships, rather than the more ecologically relevant social hierarchies or networks, hence failing to account for how dyadic relationships may be adjusted within larger social groups. We used a novel statistical method: randomized Elo-ratings, to infer the social hierarchy of 18 male pheasants, Phasianus colchicus , while in a captive, mixed-sex group with a linear hierarchy. We assayed individual learning performance of these males on a binary spatial discrimination task to investigate whether inter-individual variation in performance is associated with group social rank. Task performance improved with increasing trial number and was positively related to social rank, with higher ranking males showing greater levels of success. Motivation to participate in the task was not related to social rank or task performance, thus indicating that these rank-related differences are not a consequence of differences in motivation to complete the task. Our results provide important information about how variation in cognitive performance relates to an individual's social rank within a group. Whether the social environment causes differences in learning performance or instead, inherent differences in learning ability predetermine rank remains to be tested.

  1. Associations between polygenic risk for schizophrenia and brain function during probabilistic learning in healthy individuals.

    Science.gov (United States)

    Lancaster, Thomas M; Ihssen, Niklas; Brindley, Lisa M; Tansey, Katherine E; Mantripragada, Kiran; O'Donovan, Michael C; Owen, Michael J; Linden, David E J

    2016-02-01

    A substantial proportion of schizophrenia liability can be explained by additive genetic factors. Risk profile scores (RPS) directly index risk using a summated total of common risk variants weighted by their effect. Previous studies suggest that schizophrenia RPS predict alterations to neural networks that support working memory and verbal fluency. In this study, we apply schizophrenia RPS to fMRI data to elucidate the effects of polygenic risk on functional brain networks during a probabilistic-learning neuroimaging paradigm. The neural networks recruited during this paradigm have previously been shown to be altered to unmedicated schizophrenia patients and relatives of schizophrenia patients, which may reflect genetic susceptibility. We created schizophrenia RPS using summary data from the Psychiatric Genetic Consortium (Schizophrenia Working Group) for 83 healthy individuals and explore associations between schizophrenia RPS and blood oxygen level dependency (BOLD) during periods of choice behavior (switch-stay) and reflection upon choice outcome (reward-punishment). We show that schizophrenia RPS is associated with alterations in the frontal pole (PWHOLE-BRAIN-CORRECTED  = 0.048) and the ventral striatum (PROI-CORRECTED  = 0.036), during choice behavior, but not choice outcome. We suggest that the common risk variants that increase susceptibility to schizophrenia can be associated with alterations in the neural circuitry that support the processing of changing reward contingencies. Hum Brain Mapp 37:491-500, 2016. © 2015 Wiley Periodicals, Inc. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

  2. Nicotine Withdrawal Disrupts Contextual Learning but Not Recall of Prior Contextual Associations: Implications for Nicotine Addiction

    OpenAIRE

    Portugal, George S.; Gould, Thomas J.

    2008-01-01

    Interactions between nicotine and learning could contribute to nicotine addiction. Although previous research indicates that nicotine withdrawal disrupts contextual learning, the effects of nicotine withdrawal on contextual memories acquired before withdrawal are unknown. The present study investigated whether nicotine withdrawal disrupted recall of prior contextual memories by examining the effects of nicotine withdrawal on recall of nicotine conditioned place preference (CPP) and contextual...

  3. Plasticity of left perisylvian white-matter tracts is associated with individual differences in math learning.

    Science.gov (United States)

    Jolles, Dietsje; Wassermann, Demian; Chokhani, Ritika; Richardson, Jennifer; Tenison, Caitlin; Bammer, Roland; Fuchs, Lynn; Supekar, Kaustubh; Menon, Vinod

    2016-04-01

    Plasticity of white matter tracts is thought to be essential for cognitive development and academic skill acquisition in children. However, a dearth of high-quality diffusion tensor imaging (DTI) data measuring longitudinal changes with learning, as well as methodological difficulties in multi-time point tract identification have limited our ability to investigate plasticity of specific white matter tracts. Here, we examine learning-related changes of white matter tracts innervating inferior parietal, prefrontal and temporal regions following an intense 2-month math tutoring program. DTI data were acquired from 18 third grade children, both before and after tutoring. A novel fiber tracking algorithm based on a White Matter Query Language (WMQL) was used to identify three sections of the superior longitudinal fasciculus (SLF) linking frontal and parietal (SLF-FP), parietal and temporal (SLF-PT) and frontal and temporal (SLF-FT) cortices, from which we created child-specific probabilistic maps. The SLF-FP, SLF-FT, and SLF-PT tracts identified with the WMQL method were highly reliable across the two time points and showed close correspondence to tracts previously described in adults. Notably, individual differences in behavioral gains after 2 months of tutoring were specifically correlated with plasticity in the left SLF-FT tract. Our results extend previous findings of individual differences in white matter integrity, and provide important new insights into white matter plasticity related to math learning in childhood. More generally, our quantitative approach will be useful for future studies examining longitudinal changes in white matter integrity associated with cognitive skill development.

  4. Subjective learning discounts test type: evidence from an associative learning and transfer task.

    Science.gov (United States)

    Touron, Dayna R; Hertzog, Christopher; Speagle, James Z

    2010-01-01

    We evaluated the extent to which memory test format and test transfer influence the dynamics of metacognitive judgments. Participants completed two study-test phases for paired-associates, with or without transferring test type, in one of four conditions: (1) recognition then recall, (2) recall then recognition, (3) recognition throughout, or (4) recall throughout. Global judgments were made prestudy, poststudy, and posttest for each phase; judgments of learning (JOLs) following item study were also collected. Results suggest that metacognitive judgment accuracy varies substantially by memory test type. Whereas underconfidence in JOLs and global predictions increases with recall practice (Koriat's underconfidence-with-practice effect), underconfidence decreases with recognition practice. Moreover, performance changes when transferring test type were not fully anticipated by pretest judgments.

  5. Factors associated with learning management in Mexican micro-entrepreneurs

    Directory of Open Access Journals (Sweden)

    Alejandro Mungaray Lagarda

    2016-10-01

    Full Text Available The learning capacity of social based Mexican micro-entrepreneurs to generate new knowledge and incorporate it to its products and services is evaluated. The above is done through a confirmatory factor analysis and structural linear equation system, and the presence of static and dynamic dimensions in learning capacity, which are represented by individual stocks and flows of knowledge. The positive relationship between them demonstrates the presence of learning processes that impact positively their economic performance.

  6. Predicting Protein-protein Association Rates using Coarse-grained Simulation and Machine Learning

    Science.gov (United States)

    Xie, Zhong-Ru; Chen, Jiawen; Wu, Yinghao

    2017-04-01

    Protein-protein interactions dominate all major biological processes in living cells. We have developed a new Monte Carlo-based simulation algorithm to study the kinetic process of protein association. We tested our method on a previously used large benchmark set of 49 protein complexes. The predicted rate was overestimated in the benchmark test compared to the experimental results for a group of protein complexes. We hypothesized that this resulted from molecular flexibility at the interface regions of the interacting proteins. After applying a machine learning algorithm with input variables that accounted for both the conformational flexibility and the energetic factor of binding, we successfully identified most of the protein complexes with overestimated association rates and improved our final prediction by using a cross-validation test. This method was then applied to a new independent test set and resulted in a similar prediction accuracy to that obtained using the training set. It has been thought that diffusion-limited protein association is dominated by long-range interactions. Our results provide strong evidence that the conformational flexibility also plays an important role in regulating protein association. Our studies provide new insights into the mechanism of protein association and offer a computationally efficient tool for predicting its rate.

  7. Associative and sensorimotor learning for parenting involves mirror neurons under the influence of oxytocin.

    Science.gov (United States)

    Ho, S Shaun; Macdonald, Adam; Swain, James E

    2014-04-01

    Mirror neuron-based associative learning may be understood according to associative learning theories, in addition to sensorimotor learning theories. This is important for a comprehensive understanding of the role of mirror neurons and related hormone modulators, such as oxytocin, in complex social interactions such as among parent-infant dyads and in examples of mirror neuron function that involve abnormal motor systems such as depression.

  8. Associative and sensorimotor learning for parenting involves mirror neurons under the influence of oxytocin

    OpenAIRE

    Ho, S. Shaun; MacDonald, Adam; Swain, James E.

    2014-01-01

    Mirror neuron–based associative learning may be understood according to associative learning theories, in addition to sensorimotor learning theories. This is important for a comprehensive understanding of the role of mirror neurons and related hormone modulators, such as oxytocin, in complex social interactions such as among parent–infant dyads and in examples of mirror neuron function that involve abnormal motor systems such as depression.

  9. Contingencies: Learning Numerical and Emotional Associations in an Uncertain World

    NARCIS (Netherlands)

    B. de Langhe (Bart)

    2011-01-01

    textabstractThe ability to learn about the relation or covariation between events happening in the world is probably the most critical aspect of human cognition. This dissertation examines how the human mind learns numerical and emotional relations and explores consequences for managerial and

  10. Can zebrafish learn spatial tasks? An empirical analysis of place and single CS-US associative learning.

    Science.gov (United States)

    Karnik, Indraneel; Gerlai, Robert

    2012-08-01

    The zebrafish may be an ideal tool with which genes underlying learning and memory can be identified and functionally investigated. From a translational viewpoint, relational learning and episodic memory are particularly important as their impairment is the hallmark of prevalent human neurodegenerative diseases. Recent reports suggest that zebrafish are capable of solving complex relational-type associative learning tasks, namely spatial learning tasks. However, it is not known whether good performance in these tasks was truly based upon relational learning or upon a single CS-US association. Here we study whether zebrafish can find a rewarding stimulus (sight of conspecifics) based upon a single associative cue or/and upon the location of the reward using a method conceptually similar to 'context and cue dependent fear conditioning' employed with rodents. Our results confirm that zebrafish can form an association between a salient visual cue and the rewarding stimulus and at the same time they can also learn where the reward is presented. Although our results do not prove that zebrafish form a dynamic spatial map of their surroundings and use this map to locate their reward, they do show that these fish perform similarly to rodents whose hippocampal function is unimpaired. These results further strengthen the notion that complex cognitive abilities exist in the zebrafish and thus they may be analyzed using the excellent genetic tool set developed for this simple vertebrate. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Using variability to guide dimensional weighting: Associative mechanisms in early word learning

    Science.gov (United States)

    Apfelbaum, Keith S.; McMurray, Bob

    2013-01-01

    At 14 months, children appear to struggle to apply their fairly well developed speech perception abilities to learning similar sounding words (e.g. bih/dih; Stager & Werker, 1997). However, variability in non-phonetic aspects of the training stimuli seems to aid word learning at this age. Extant theories of early word learning cannot account for this benefit of variability. We offer a simple explanation for this range of effects based on associative learning. Simulations suggest that if infants encode both non-contrastive information (e.g. cues to speaker voice) and meaningful linguistic cues (e.g. place of articulation or voicing), then associative learning mechanisms predict these variability effects in early word learning. Crucially, this means that despite the importance of task variables in predicting performance, this body of work shows that phonological categories are still developing in this age, and that the structure of non-informative cues has critical influences on word learning abilities. PMID:21609356

  12. The Association between Students' Style of Learning Preferences, Social Presence, Collaborative Learning and Learning Outcomes

    Science.gov (United States)

    Chen, Clement; Jones, Keith T.; Xu, Shawn

    2018-01-01

    Differences in styles of learning have become important considerations at all levels of education over the last several years. Examining college students' preferred style of learning is useful for course design and effective instructional methods. Using the Felder-Silverman Index of Learning Styles (ILS), we investigate how students' styles of…

  13. The effects of aging on the neural basis of implicit associative learning in a probabilistic triplets learning task.

    Science.gov (United States)

    Simon, Jessica R; Vaidya, Chandan J; Howard, James H; Howard, Darlene V

    2012-02-01

    Few studies have investigated how aging influences the neural basis of implicit associative learning, and available evidence is inconclusive. One emerging behavioral pattern is that age differences increase with practice, perhaps reflecting the involvement of different brain regions with training. Many studies report hippocampal involvement early on with learning becoming increasingly dependent on the caudate with practice. We tested the hypothesis that the contribution of these regions to learning changes with age because of differential age-related declines in the striatum and hippocampi. We assessed age-related differences in brain activation during implicit associative learning using the Triplets Learning Task. Over three event-related fMRI runs, 11 younger and 12 healthy older adults responded to only the third (target) stimulus in sequences of three stimuli ("triplets") by corresponding key press. Unbeknown to participants, the first stimulus' location predicted one target location for 80% of trials and another target location for 20% of trials. Both age groups learned associative regularities but differences in favor of the younger adults emerged with practice. The neural basis of learning (response to predictability) was examined by identifying regions that showed a greater response to triplets that occurred more frequently. Both age groups recruited the hippocampus early, but with training, the younger adults recruited their caudate whereas the older adults continued to rely on their hippocampus. This pattern enables older adults to maintain near-young levels of performance early in training, but not later, and adds to evidence that implicit associative learning is supported by different brain networks in younger and older adults.

  14. Multivoxel Object Representations in Adult Human Visual Cortex Are Flexible: An Associative Learning Study.

    Science.gov (United States)

    Senoussi, Mehdi; Berry, Isabelle; VanRullen, Rufin; Reddy, Leila

    2016-06-01

    Learning associations between co-occurring events enables us to extract structure from our environment. Medial-temporal lobe structures are critical for associative learning. However, the role of the ventral visual pathway (VVP) in associative learning is not clear. Do multivoxel object representations in the VVP reflect newly formed associations? We show that VVP multivoxel representations become more similar to each other after human participants learn arbitrary new associations between pairs of unrelated objects (faces, houses, cars, chairs). Participants were scanned before and after 15 days of associative learning. To evaluate how object representations changed, a classifier was trained on discriminating two nonassociated categories (e.g., faces/houses) and tested on discriminating their paired associates (e.g., cars/chairs). Because the associations were arbitrary and counterbalanced across participants, there was initially no particular reason for this cross-classification decision to tend toward either alternative. Nonetheless, after learning, cross-classification performance increased in the VVP (but not hippocampus), on average by 3.3%, with some voxels showing increases of up to 10%. For example, a chair multivoxel representation that initially resembled neither face nor house representations was, after learning, classified as more similar to that of faces for participants who associated chairs with faces and to that of houses for participants who associated chairs with houses. Additionally, learning produced long-lasting perceptual consequences. In a behavioral priming experiment performed several months later, the change in cross-classification performance was correlated with the degree of priming. Thus, VVP multivoxel representations are not static but become more similar to each other after associative learning.

  15. Multiple target tracking by learning-based hierarchical association of detection responses.

    Science.gov (United States)

    Huang, Chang; Li, Yuan; Nevatia, Ramakant

    2013-04-01

    We propose a hierarchical association approach to multiple target tracking from a single camera by progressively linking detection responses into longer track fragments (i.e., tracklets). Given frame-by-frame detection results, a conservative dual-threshold method that only links very similar detection responses between consecutive frames is adopted to generate initial tracklets with minimum identity switches. Further association of these highly fragmented tracklets at each level of the hierarchy is formulated as a Maximum A Posteriori (MAP) problem that considers initialization, termination, and transition of tracklets as well as the possibility of them being false alarms, which can be efficiently computed by the Hungarian algorithm. The tracklet affinity model, which measures the likelihood of two tracklets belonging to the same target, is a linear combination of automatically learned weak nonparametric models upon various features, which is distinct from most of previous work that relies on heuristic selection of parametric models and manual tuning of their parameters. For this purpose, we develop a novel bag ranking method and train the crucial tracklet affinity models by the boosting algorithm. This bag ranking method utilizes the soft max function to relax the oversufficient objective function used by the conventional instance ranking method. It provides a tighter upper bound of empirical errors in distinguishing correct associations from the incorrect ones, and thus yields more accurate tracklet affinity models for the tracklet association problem. We apply this approach to the challenging multiple pedestrian tracking task. Systematic experiments conducted on two real-life datasets show that the proposed approach outperforms previous state-of-the-art algorithms in terms of tracking accuracy, in particular, considerably reducing fragmentations and identity switches.

  16. Associative vocabulary learning: development and testing of two paradigms for the (re-) acquisition of action- and object-related words.

    Science.gov (United States)

    Freundlieb, Nils; Ridder, Volker; Dobel, Christian; Enriquez-Geppert, Stefanie; Baumgaertner, Annette; Zwitserlood, Pienie; Gerloff, Christian; Hummel, Friedhelm C; Liuzzi, Gianpiero

    2012-01-01

    Despite a growing number of studies, the neurophysiology of adult vocabulary acquisition is still poorly understood. One reason is that paradigms that can easily be combined with neuroscientfic methods are rare. Here, we tested the efficiency of two paradigms for vocabulary (re-) acquisition, and compared the learning of novel words for actions and objects. Cortical networks involved in adult native-language word processing are widespread, with differences postulated between words for objects and actions. Words and what they stand for are supposed to be grounded in perceptual and sensorimotor brain circuits depending on their meaning. If there are specific brain representations for different word categories, we hypothesized behavioural differences in the learning of action-related and object-related words. Paradigm A, with the learning of novel words for body-related actions spread out over a number of days, revealed fast learning of these new action words, and stable retention up to 4 weeks after training. The single-session Paradigm B employed objects and actions. Performance during acquisition did not differ between action-related and object-related words (time*word category: p = 0.01), but the translation rate was clearly better for object-related (79%) than for action-related words (53%, p = 0.002). Both paradigms yielded robust associative learning of novel action-related words, as previously demonstrated for object-related words. Translation success differed for action- and object-related words, which may indicate different neural mechanisms. The paradigms tested here are well suited to investigate such differences with neuroscientific means. Given the stable retention and minimal requirements for conscious effort, these learning paradigms are promising for vocabulary re-learning in brain-lesioned people. In combination with neuroimaging, neuro-stimulation or pharmacological intervention, they may well advance the understanding of language learning

  17. A genome wide association study of mathematical ability reveals an association at chromosome 3q29, a locus associated with autism and learning difficulties: a preliminary study.

    Directory of Open Access Journals (Sweden)

    Simon Baron-Cohen

    Full Text Available Mathematical ability is heritable, but few studies have directly investigated its molecular genetic basis. Here we aimed to identify specific genetic contributions to variation in mathematical ability. We carried out a genome wide association scan using pooled DNA in two groups of U.K. samples, based on end of secondary/high school national academic exam achievement: high (n = 419 versus low (n = 183 mathematical ability while controlling for their verbal ability. Significant differences in allele frequencies between these groups were searched for in 906,600 SNPs using the Affymetrix GeneChip Human Mapping version 6.0 array. After meeting a threshold of p<1.5×10(-5, 12 SNPs from the pooled association analysis were individually genotyped in 542 of the participants and analyzed to validate the initial associations (lowest p-value 1.14 ×10(-6. In this analysis, one of the SNPs (rs789859 showed significant association after Bonferroni correction, and four (rs10873824, rs4144887, rs12130910 rs2809115 were nominally significant (lowest p-value 3.278 × 10(-4. Three of the SNPs of interest are located within, or near to, known genes (FAM43A, SFT2D1, C14orf64. The SNP that showed the strongest association, rs789859, is located in a region on chromosome 3q29 that has been previously linked to learning difficulties and autism. rs789859 lies 1.3 kbp downstream of LSG1, and 700 bp upstream of FAM43A, mapping within the potential promoter/regulatory region of the latter. To our knowledge, this is only the second study to investigate the association of genetic variants with mathematical ability, and it highlights a number of interesting markers for future study.

  18. Attention Cueing and Activity Equally Reduce False Alarm Rate in Visual-Auditory Associative Learning through Improving Memory.

    Science.gov (United States)

    Nikouei Mahani, Mohammad-Ali; Haghgoo, Hojjat Allah; Azizi, Solmaz; Nili Ahmadabadi, Majid

    2016-01-01

    In our daily life, we continually exploit already learned multisensory associations and form new ones when facing novel situations. Improving our associative learning results in higher cognitive capabilities. We experimentally and computationally studied the learning performance of healthy subjects in a visual-auditory sensory associative learning task across active learning, attention cueing learning, and passive learning modes. According to our results, the learning mode had no significant effect on learning association of congruent pairs. In addition, subjects' performance in learning congruent samples was not correlated with their vigilance score. Nevertheless, vigilance score was significantly correlated with the learning performance of the non-congruent pairs. Moreover, in the last block of the passive learning mode, subjects significantly made more mistakes in taking non-congruent pairs as associated and consciously reported lower confidence. These results indicate that attention and activity equally enhanced visual-auditory associative learning for non-congruent pairs, while false alarm rate in the passive learning mode did not decrease after the second block. We investigated the cause of higher false alarm rate in the passive learning mode by using a computational model, composed of a reinforcement learning module and a memory-decay module. The results suggest that the higher rate of memory decay is the source of making more mistakes and reporting lower confidence in non-congruent pairs in the passive learning mode.

  19. Use of the Learning together technique associated to the theory of significative learning

    Directory of Open Access Journals (Sweden)

    Ester López Donoso

    2008-09-01

    Full Text Available This article deals with an experimental research, regarding a qualitative and quantitative design, applied to a group of students of General Physics course during the first semester of the university career of Engineering. Historically, students of this course present learning difficulties that directly affect their performance, conceptualization and permanence in the university. The present methodology integrates the collaborative learning, denominated Learning Together", with the theory of significant learning to avoid the above-written difficulties. Results of this research show that the proposed methodology works properly, especially to improve the conceptualization.

  20. Visual and olfactory associative learning in the malaria vector Anopheles gambiae sensu stricto

    Directory of Open Access Journals (Sweden)

    Chilaka Nora

    2012-01-01

    Full Text Available Abstract Background Memory and learning are critical aspects of the ecology of insect vectors of human pathogens because of their potential effects on contacts between vectors and their hosts. Despite this epidemiological importance, there have been only a limited number of studies investigating associative learning in insect vector species and none on Anopheline mosquitoes. Methods A simple behavioural assays was developed to study visual and olfactory associative learning in Anopheles gambiae, the main vector of malaria in Africa. Two contrasted membrane qualities or levels of blood palatability were used as reinforcing stimuli for bi-directional conditioning during blood feeding. Results Under such experimental conditions An. gambiae females learned very rapidly to associate visual (chequered and white patterns and olfactory cues (presence and absence of cheese or Citronella smell with the reinforcing stimuli (bloodmeal quality and remembered the association for up to three days. Associative learning significantly increased with the strength of the conditioning stimuli used. Importantly, learning sometimes occurred faster when a positive reinforcing stimulus (palatable blood was associated with an innately preferred cue (such as a darker visual pattern. However, the use of too attractive a cue (e.g. Shropshire cheese smell was counter-productive and decreased learning success. Conclusions The results address an important knowledge gap in mosquito ecology and emphasize the role of associative memory for An. gambiae's host finding and blood-feeding behaviour with important potential implications for vector control.

  1. Does academic performance or personal growth share a stronger association with learning environment perception?

    OpenAIRE

    Colbert-Getz, Jorie M.; Tackett, Sean; Wright, Scott M.; Shochet, Robert S.

    2016-01-01

    Objectives This study was conducted to characterize the relative strength of associations of learning environment perception with academic performance and with personal growth. Methods In 2012-2014 second and third year students at Johns Hopkins University School of Medicine completed a learning environment survey and personal growth scale. Hierarchical linear regression analysis was employed to determine if the proportion of variance in learning environment scores accounted for by personal g...

  2. Respective Role of the Dorsal Hippocampus and the Entorhinal Cortex during the Recombination of Previously Learned Olfactory-Tactile Associations in the Rat

    Science.gov (United States)

    Boisselier, Lise; Ferry, Barbara; Gervais, Rémi

    2017-01-01

    The hippocampal formation has been extensively described as a key component for object recognition in conjunction with place and context. The present study aimed at describing neural mechanisms in the hippocampal formation that support olfactory-tactile (OT) object discrimination in a task where space and context were not taken into account. The…

  3. Object associations of early-learned light and heavy English verbs.

    Science.gov (United States)

    Maouene, Josita; Laakso, Aarre; Smith, Linda B

    2011-02-01

    Many of the verbs that young children learn early have been characterized as 'light.' However, there is no agreed upon definition of 'lightness' and no useable metric that could be applied to a wide array of verbs. This article provides evidence for one metric by which the 'lightness' of early-learned verbs might be measured: the number of objects with which they are associated (in adult judgment) or co-occur (in speech to and by children). The results suggest that early-learned light verbs and heavy verbs differ in the breadth of the objects they are associated with: light verbs have weak associations with specific objects, whereas heavy verbs are strongly associated with specific objects. However, there is an indication that verbs have narrower associations to objects in speech to children. The methodological usefulness of this metric is discussed as are the implications of the patterns of distributions for children's learning of common verbs.

  4. [Association between self-directed learning behaviors, socio-demographic and academic variables among medical students].

    Science.gov (United States)

    Fasce H, Eduardo; Ortega B, Javiera; Pérez V, Cristhian; Márquez U, Carolina; Parra P, Paula; Ortiz M, Liliana; Matus, Olga

    2013-09-01

    Medical education must encourage autonomous learning behaviors among students. However the great income profile disparity among university students may influence their capacity to acquire such skills. To assess the association between self-directed learning, socio-demographic and academic variables. The self-directed learning readiness scale was applied to 202 medical students aged between 17 and 25 years (64% males). Simultaneously information about each surveyed participant was obtained from the databases of the medical school. There is an association between socio-demographic and academic variables with the general scale of self-directed learning and the subscales learning planning and willingness to learn. Participants coming from municipal schools have a greater willingness to learn than their counterparts coming from subsidized and private schools. High school grades are related to self-directed learning and the subscales learning planning and self-assessment. Among the surveyed medical students, there is a relationship between self-directed learning behaviors, the type of school where they come from and the grades that they obtained during high school.

  5. Probabilistic Category Learning in Developmental Dyslexia: Evidence from Feedback and Paired-Associate Weather Prediction Tasks

    Science.gov (United States)

    Gabay, Yafit; Vakil, Eli; Schiff, Rachel; Holt, Lori L.

    2015-01-01

    Objective Developmental dyslexia is presumed to arise from specific phonological impairments. However, an emerging theoretical framework suggests that phonological impairments may be symptoms stemming from an underlying dysfunction of procedural learning. Method We tested procedural learning in adults with dyslexia (n=15) and matched-controls (n=15) using two versions of the Weather Prediction Task: Feedback (FB) and Paired-associate (PA). In the FB-based task, participants learned associations between cues and outcomes initially by guessing and subsequently through feedback indicating the correctness of response. In the PA-based learning task, participants viewed the cue and its associated outcome simultaneously without overt response or feedback. In both versions, participants trained across 150 trials. Learning was assessed in a subsequent test without presentation of the outcome, or corrective feedback. Results The Dyslexia group exhibited impaired learning compared with the Control group on both the FB and PA versions of the weather prediction task. Conclusions The results indicate that the ability to learn by feedback is not selectively impaired in dyslexia. Rather it seems that the probabilistic nature of the task, shared by the FB and PA versions of the weather prediction task, hampers learning in those with dyslexia. Results are discussed in light of procedural learning impairments among participants with dyslexia. PMID:25730732

  6. The study of associative learning: mapping from psychological to neural levels of analysis.

    Science.gov (United States)

    Delamater, Andrew R; Lattal, K Matthew

    2014-02-01

    One of the major achievements of the last century of research in experimental psychology is the identification of a coherent set of theories and principles to characterize the nature of simple forms of associative learning. Major advances are also currently being made at a rapid pace in the neurobiology of associative learning, and, interestingly, we are beginning to see how a mapping from a psychological level of analysis to underlying neurobiological mechanisms is possible. This collection of papers honors the illustrative careers of four major learning theorists from the experimental psychology tradition (Robert Rescorla, Allan Wagner, Nicholas Mackintosh, Anthony Dickinson) who have helped shape our understanding of behavioral principles. The collection of works in this special issue reflects common interests among researchers working at both psychological and neurobiological levels of analysis towards a more comprehensive understanding of basic associative learning processes as they relate to several key issues identified and intensively studied by these influential learning theorists. These consist of the questions regarding (1) the critical conditions enabling learning, (2) the contents of learning, and (3) the rules that translate learning into performance. In one way or another, the separate contributions in this issue address these fundamental questions as they relate to a wide variety of currently exciting topics in the study of the neurobiology of learning and memory. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Examining the nature of impairment in visual paired associate learning in amnestic mild cognitive impairment.

    Science.gov (United States)

    Harel, Brian T; Darby, David; Pietrzak, Robert H; Ellis, Kathryn A; Snyder, Peter J; Maruff, Paul

    2011-11-01

    Visual spatial learning is impaired in mild cognitive impairment (MCI) although the nature of this impairment is not clear. This study investigated the nature and magnitude of errors made by adults with amnestic MCI (aMCI) when learning pattern-location paired associations in a continuous manner. Visual associate learning was measured using the Continuous Paired Associate Learning (CPAL) task in which 30 adults who met clinical criteria for aMCI and 30 matched controls were required to learn a set of associations between patterns and locations across increasing memory loads (two, four, six, and eight). As hypothesized, the aMCI group made more total errors than controls for all memory loads above two. However, the rate of increase in errors with memory load in the aMCI group was approximately twice that for controls. In controls, errors on the CPAL task reflected almost exclusively difficulty in memory. In the aMCI group, errors on the CPAL reflected limitations in associative learning but also in short-term memory and response monitoring. These results suggest that impairments in specific aspects of executive function and working memory might contribute to poor performance on visual paired associate learning in aMCI.

  8. Tailor-made memory: natural differences in associative olfactory learning in two closely related wasp species

    NARCIS (Netherlands)

    Berg, van den M.

    2009-01-01

    Learning and memory formation are often seen as traits that are purely beneficial, but they are associated with metabolic costs as well. Since costs and gains of learning and memory are expected to vary between species, the ease and speed with which stable (consolidated) long-term memory (LTM) is

  9. University of Central Florida and the American Association of State Colleges and Universities: Blended Learning Toolkit

    Science.gov (United States)

    EDUCAUSE, 2014

    2014-01-01

    The Blended Learning Toolkit supports the course redesign approach, and interest in its openly available clearinghouse of online tools, strategies, curricula, and other materials to support the adoption of blended learning continues to grow. When the resource originally launched in July 2011, 20 AASCU [American Association of State Colleges and…

  10. Effects of Learning Experience on Forgetting Rates of Item and Associative Memories

    Science.gov (United States)

    Yang, Jiongjiong; Zhan, Lexia; Wang, Yingying; Du, Xiaoya; Zhou, Wenxi; Ning, Xueling; Sun, Qing; Moscovitch, Morris

    2016-01-01

    Are associative memories forgotten more quickly than item memories, and does the level of original learning differentially influence forgetting rates? In this study, we addressed these questions by having participants learn single words and word pairs once (Experiment 1), three times (Experiment 2), and six times (Experiment 3) in a massed…

  11. Cognitive specialization for learning faces is associated with shifts in the brain transcriptome of a social wasp.

    Science.gov (United States)

    Berens, Ali J; Tibbetts, Elizabeth A; Toth, Amy L

    2017-06-15

    The specialized ability to learn and recall individuals based on distinct facial features is known in only a few, large-brained social taxa. Social paper wasps in the genus Polistes are the only insects known to possess this form of cognitive specialization. We analyzed genome-wide brain gene expression during facial and pattern training for two species of paper wasps ( P. fuscatus , which has face recognition, and P. metricus , which does not) using RNA sequencing. We identified 237 transcripts associated with face specialization in P. fuscatus , including some transcripts involved in neuronal signaling (serotonin receptor and tachykinin). Polistes metricus that learned faces (without specialized learning) and P. fuscatus in social interactions with familiar partners (from a previous study) showed distinct sets of brain differentially expressed transcripts. These data suggest face specialization in P. fuscatus is related to shifts in the brain transcriptome associated with genes distinct from those related to general visual learning and social interactions. © 2017. Published by The Company of Biologists Ltd.

  12. 9. Challenges Associated with Learning Oral Diagnostic Sciences, A ...

    African Journals Online (AJOL)

    user

    categorize specified challenges of learning ODS in. Nigeria. METHODS. This was a cross sectional survey of undergraduate dental students (UDS) and resident doctors (RDS) in dental surgery in five institutions in Nigeria. (University of Ibadan and the University College. Hospital, University of Lagos and Lagos University.

  13. Greater mindful eating practice is associated with better reversal learning

    NARCIS (Netherlands)

    Janssen, Lieneke K.; Duif, Iris; Loon, Van Ilke; Vries, De Jeanne H.M.; Speckens, Anne E.M.; Cools, Roshan; Aarts, Esther

    2018-01-01

    Mindfulness-based interventions are thought to reduce compulsive behavior such as overeating by promoting behavioral flexibility. Here the main aim was to provide support for mindfulness-mediated improvements in reversal learning, a direct measure of behavioral flexibility. We investigated

  14. Business Models Associated with Distance Learning in Higher Education

    Science.gov (United States)

    Wang, Shouhong; Wang, Hai

    2017-01-01

    Textbook prices are continuously rising in higher education. This paper analyzes a business model which makes commercial textbooks more expensive, and explains why this issue tends to be more severe in the field of distance learning in higher education. It reports a case of adoption of open educational resources (OER) textbook for an online course…

  15. Motivated strategies for learning and their association with academic ...

    African Journals Online (AJOL)

    Students with prior educational experience and those who attended peermentoring sessions had significantly higher learning strategy scores. Significant but moderate relationships were found between academic performance and the motivation strategies subsumed within the categories 'task value' and 'self-efficacy for ...

  16. Protein dynamics associated with failed and rescued learning in the Ts65Dn mouse model of Down syndrome.

    Directory of Open Access Journals (Sweden)

    Md Mahiuddin Ahmed

    Full Text Available Down syndrome (DS is caused by an extra copy of human chromosome 21 (Hsa21. Although it is the most common genetic cause of intellectual disability (ID, there are, as yet, no effective pharmacotherapies. The Ts65Dn mouse model of DS is trisomic for orthologs of ∼55% of Hsa21 classical protein coding genes. These mice display many features relevant to those seen in DS, including deficits in learning and memory (L/M tasks requiring a functional hippocampus. Recently, the N-methyl-D-aspartate (NMDA receptor antagonist, memantine, was shown to rescue performance of the Ts65Dn in several L/M tasks. These studies, however, have not been accompanied by molecular analyses. In previous work, we described changes in protein expression induced in hippocampus and cortex in control mice after exposure to context fear conditioning (CFC, with and without memantine treatment. Here, we extend this analysis to Ts65Dn mice, measuring levels of 85 proteins/protein modifications, including components of MAP kinase and MTOR pathways, and subunits of NMDA receptors, in cortex and hippocampus of Ts65Dn mice after failed learning in CFC and after learning was rescued by memantine. We show that, compared with wild type littermate controls, (i of the dynamic responses seen in control mice in normal learning, >40% also occur in Ts65Dn in failed learning or are compensated by baseline abnormalities, and thus are considered necessary but not sufficient for successful learning, and (ii treatment with memantine does not in general normalize the initial protein levels but instead induces direct and indirect responses in approximately half the proteins measured and results in normalization of the endpoint protein levels. Together, these datasets provide a first view of the complexities associated with pharmacological rescue of learning in the Ts65Dn. Extending such studies to additional drugs and mouse models of DS will aid in identifying pharmacotherapies for effective

  17. Cortico-hippocampal interaction and adaptive stimulus representation: A neurocomputational theory of associative learning and memory.

    NARCIS (Netherlands)

    Gluck, M.A.; Myers, C.E; Meeter, M.

    2005-01-01

    Computational models of the hippocampal region link psychological theories of associative learning with their underlying physiological and anatomical substrates. Our approach to theory development began with a broad description of the computations that depend on the hippocampal region in classical

  18. A high-capacity model for one shot association learning in the brain

    Directory of Open Access Journals (Sweden)

    Hafsteinn eEinarsson

    2014-11-01

    Full Text Available We present a high-capacity model for one-shot association learning(hetero-associative memory in sparse networks. We assume that basic patternsare pre-learned in networks and associations between two patterns are presentedonly once and have to be learned immediately. The model is a combination of anAmit-Fusi like network sparsely connected to a Willshaw type network. Thelearning procedure is palimpsest and comes from earlier work on one-shotpattern learning. However, in our setup we can enhance the capacity of thenetwork by iterative retrieval. This yields a model for sparse brain-likenetworks in which populations of a few thousand neurons are capable of learninghundreds of associations even if they are presented only once. The analysis ofthe model is based on a novel result by Janson et. al. on bootstrappercolation in random graphs.

  19. BDNF val66met genotype and schizotypal personality traits interact to influence probabilistic association learning.

    Science.gov (United States)

    Skilleter, Ashley Jayne; Weickert, Cynthia Shannon; Moustafa, Ahmed Abdelhalim; Gendy, Rasha; Chan, Mico; Arifin, Nur; Mitchell, Philip Bowden; Weickert, Thomas Wesley

    2014-11-01

    The brain derived neurotrophic factor (BDNF) val66met polymorphism rs6265 influences learning and may represent a risk factor for schizophrenia. Healthy people with high schizotypal personality traits display cognitive deficits that are similar to but not as severe as those observed in schizophrenia and they can be studied without confounds of antipsychotics or chronic illness. How genetic variation in BDNF may impact learning in individuals falling along the schizophrenia spectrum is unknown. We predicted that schizotypal personality traits would influence learning and that schizotypal personality-based differences in learning would vary depending on the BDNF val66met genotype. Eighty-nine healthy adults completed the Schizotypal Personality Questionnaire (SPQ) and a probabilistic association learning test. Blood samples were genotyped for the BDNF val66met polymorphism. An ANOVA was performed with BDNF genotype (val homozygotes and met-carriers) and SPQ score (high/low) as grouping variables and probabilistic association learning as the dependent variable. Participants with low SPQ scores (fewer schizotypal personality traits) showed significantly better learning than those with high SPQ scores. BDNF met-carriers displaying few schizotypal personality traits performed best, whereas BDNF met-carriers displaying high schizotypal personality traits performed worst. Thus, the BDNF val66met polymorphism appears to influence probabilistic association learning differently depending on the extent of schizotypal personality traits displayed. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  20. The Learning Healthcare System and Cardiovascular Care: A Scientific Statement From the American Heart Association.

    Science.gov (United States)

    Maddox, Thomas M; Albert, Nancy M; Borden, William B; Curtis, Lesley H; Ferguson, T Bruce; Kao, David P; Marcus, Gregory M; Peterson, Eric D; Redberg, Rita; Rumsfeld, John S; Shah, Nilay D; Tcheng, James E

    2017-04-04

    The learning healthcare system uses health information technology and the health data infrastructure to apply scientific evidence at the point of clinical care while simultaneously collecting insights from that care to promote innovation in optimal healthcare delivery and to fuel new scientific discovery. To achieve these goals, the learning healthcare system requires systematic redesign of the current healthcare system, focusing on 4 major domains: science and informatics, patient-clinician partnerships, incentives, and development of a continuous learning culture. This scientific statement provides an overview of how these learning healthcare system domains can be realized in cardiovascular disease care. Current cardiovascular disease care innovations in informatics, data uses, patient engagement, continuous learning culture, and incentives are profiled. In addition, recommendations for next steps for the development of a learning healthcare system in cardiovascular care are presented. © 2017 American Heart Association, Inc.

  1. Early student outcomes associated with a virtual community for learning.

    Science.gov (United States)

    Giddens, Jean Foret; Shuster, Geoff; Roehrig, Nicole

    2010-06-01

    Virtual communities represent a new and innovative approach to learning within nursing education. Because this is an emerging trend, little is known about the use of virtual communities and the impact on students and their learning. This article reports the results of a study designed to assess the initial perceived benefits of using a virtual community known as The Neighborhood in a single undergraduate baccalaureate nursing program during the first few years following development. Results showed greater benefits reported among underrepresented minority students and students who expected to receive lower than a course grade of A. In addition, findings suggest the strength of perceived benefits increases over time among all learners. These findings merely scratch the surface of additional work needed in this area. Copyright 2010, SLACK Incorporated.

  2. Associability-modulated loss learning is increased in posttraumatic stress disorder

    Science.gov (United States)

    Brown, Vanessa M; Zhu, Lusha; Wang, John M; Frueh, B Christopher

    2018-01-01

    Disproportionate reactions to unexpected stimuli in the environment are a cardinal symptom of posttraumatic stress disorder (PTSD). Here, we test whether these heightened responses are associated with disruptions in distinct components of reinforcement learning. Specifically, using functional neuroimaging, a loss-learning task, and a computational model-based approach, we assessed the mechanistic hypothesis that overreactions to stimuli in PTSD arise from anomalous gating of attention during learning (i.e., associability). Behavioral choices of combat-deployed veterans with and without PTSD were fit to a reinforcement learning model, generating trial-by-trial prediction errors (signaling unexpected outcomes) and associability values (signaling attention allocation to the unexpected outcomes). Neural substrates of associability value and behavioral parameter estimates of associability updating, but not prediction error, increased with PTSD during loss learning. Moreover, the interaction of PTSD severity with neural markers of associability value predicted behavioral choices. These results indicate that increased attention-based learning may underlie aspects of PTSD and suggest potential neuromechanistic treatment targets. PMID:29313489

  3. The role of prefrontal dopamine D1 receptors in the neural mechanisms of associative learning.

    Science.gov (United States)

    Puig, M Victoria; Miller, Earl K

    2012-06-07

    Dopamine is thought to play a major role in learning. However, while dopamine D1 receptors (D1Rs) in the prefrontal cortex (PFC) have been shown to modulate working memory-related neural activity, their role in the cellular basis of learning is unknown. We recorded activity from multiple electrodes while injecting the D1R antagonist SCH23390 in the lateral PFC as monkeys learned visuomotor associations. Blocking D1Rs impaired learning of novel associations and decreased cognitive flexibility but spared performance of already familiar associations. This suggests a greater role for prefrontal D1Rs in learning new, rather than performing familiar, associations. There was a corresponding greater decrease in neural selectivity and increase in alpha and beta oscillations in local field potentials for novel than for familiar associations. Our results suggest that weak stimulation of D1Rs observed in aging and psychiatric disorders may impair learning and PFC function by reducing neural selectivity and exacerbating neural oscillations associated with inattention and cognitive deficits. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. The amygdala complex: multiple roles in associative learning and attention.

    OpenAIRE

    Gallagher, M; Holland, P C

    1994-01-01

    Although certain neurophysiological functions of the amygdala complex in learning seem well established, the purpose of this review is to propose that an additional conceptualization of amygdala function is now needed. The research we review provides evidence that a subsystem within the amygdala provides a coordinated regulation of attentional processes. An important aspect of this additional neuropsychology of the amygdala is that it may aid in understanding the importance of connections bet...

  5. Psychosocial and Adaptive Deficits Associated With Learning Disability Subtypes.

    Science.gov (United States)

    Backenson, Erica M; Holland, Sara C; Kubas, Hanna A; Fitzer, Kim R; Wilcox, Gabrielle; Carmichael, Jessica A; Fraccaro, Rebecca L; Smith, Amanda D; Macoun, Sarah J; Harrison, Gina L; Hale, James B

    2015-01-01

    Children with specific learning disabilities (SLD) have deficits in the basic psychological processes that interfere with learning and academic achievement, and for some SLD subtypes, these deficits can also lead to emotional and/or behavior problems. This study examined psychosocial functioning in 123 students, aged 6 to 11, who underwent comprehensive evaluations for learning and/or behavior problems in two Pacific Northwest school districts. Using concordance-discordance model (C-DM) processing strengths and weaknesses SLD identification criteria, results revealed working memory SLD (n = 20), processing speed SLD (n = 30), executive SLD (n = 32), and no disability groups (n = 41). Of the SLD subtypes, repeated measures MANOVA results revealed the processing speed SLD subtype exhibited the greatest psychosocial and adaptive impairment according to teacher behavior ratings. Findings suggest processing speed deficits may be behind the cognitive and psychosocial disturbances found in what has been termed "nonverbal" SLD. Limitations, implications, and future research needs are addressed. © Hammill Institute on Disabilities 2013.

  6. The movement kinematics and learning strategies associated with adopting different foci of attention during both acquisition and anxious performance.

    Directory of Open Access Journals (Sweden)

    Gavin Peter Lawrence

    2012-11-01

    Full Text Available Research suggests that implicit strategies adopted during learning help prevent breakdown of automatic processes and subsequent performance decrements associated with the presence of pressure. According to the Constrained Action Hypothesis, automaticity of movement is promoted when adopting an external focus of attention. The purpose of the current experiment was to investigate if learning with an external focus of attention can enhance performance under subsequent pressure situations through promoting implicit learning and automaticity. Since previous research has generally used outcome measures of performance, the current study adopted measures of movement production. Specifically, we calculated within subject variability in trajectory velocity and distance travelled every 10% of movement time. This detailed kinematic analysis allowed investigation into some of the previously unexplored mechanisms responsible for the benefits of adopting an external focus of attention. Novice participants performed a 2.5m golf putt. Following a pre-test, participants were randomly assigned to one of three focus groups (internal, external, control. Participants then completed 400 acquisition trials over two consecutive days before being subjected to both a low-anxiety and high-anxiety transfer test. Dependent variables included variability, number of successful putts and mean radial error. Results revealed that variability was greater in the internal compared to the external and control groups. Putting performance revealed that all groups increased performance following acquisition. However, only the control group demonstrated a decrement in performance in the high-anxiety transfer test. These findings suggest that adopting an appropriate focus of attention during learning can prevent choking; with an external focus inhibiting the breakdown of automatic processes and an internal focus acting as a self-focus learning strategy and thus desensitizing individuals

  7. Associative learning of odor with food- or blood-meal by Culex quinquefasciatus Say (Diptera: Culicidae)

    Science.gov (United States)

    Tomberlin, Jeffery K.; Rains, Glen C.; Allan, Sandy A.; Sanford, Michelle R.; Lewis, W. Joe

    2006-11-01

    The ability of many insects to learn has been documented. However, a limited number of studies examining associative learning in medically important arthropods has been published. Investigations into the associative learning capabilities of Culex quinquefasciatus Say were conducted by adapting methods commonly used in experiments involving Hymenoptera. Male and female mosquitoes were able to learn a conditioned stimulus that consisted of an odor not normally encountered in nature (synthetic strawberry or vanilla extracts) in association with an unconditioned stimulus consisting of either a sugar (males and females) or blood (females) meal. Such information could lead to a better understanding of the ability of mosquitoes to locate and select host and food resources in nature.

  8. The acquisition of simple associations as observed in color-word contingency learning.

    Science.gov (United States)

    Lin, Olivia Y-H; MacLeod, Colin M

    2018-01-01

    Three experiments investigated the learning of simple associations in a color-word contingency task. Participants responded manually to the print colors of 3 words, with each word associated strongly to 1 of the 3 colors and weakly to the other 2 colors. Despite the words being irrelevant, response times to high-contingency stimuli and to low-contingency stimuli quickly diverged. This high-low difference remained quite constant over successive blocks of trials, evidence of stable contingency learning. Inclusion of a baseline condition-an item having no color-word contingency-permitted separation of the contingency learning effect into 2 components: a cost due to low contingency and a benefit due to high contingency. Both cost and benefit were quick to acquire, quick to extinguish, and quick to reacquire. The color-word contingency task provides a simple way to directly study the learning of associations. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  9. Is learning mindfulness associated with improved affect after mindfulness-based cognitive therapy?

    NARCIS (Netherlands)

    Schroevers, Maya J.; Brandsma, R.

    2010-01-01

    The increased popularity of mindfulness-based interventions and the growing body of empirical evidence confirming the positive effects of these interventions on well-being warrant more research to determine if the effects are indeed related to learning mindfulness. The present study extends previous

  10. Neuronal representations of stimulus associations develop in the temporal lobe during learning.

    Science.gov (United States)

    Messinger, A; Squire, L R; Zola, S M; Albright, T D

    2001-10-09

    Visual stimuli that are frequently seen together become associated in long-term memory, such that the sight of one stimulus readily brings to mind the thought or image of the other. It has been hypothesized that acquisition of such long-term associative memories proceeds via the strengthening of connections between neurons representing the associated stimuli, such that a neuron initially responding only to one stimulus of an associated pair eventually comes to respond to both. Consistent with this hypothesis, studies have demonstrated that individual neurons in the primate inferior temporal cortex tend to exhibit similar responses to pairs of visual stimuli that have become behaviorally associated. In the present study, we investigated the role of these areas in the formation of conditional visual associations by monitoring the responses of individual neurons during the learning of new stimulus pairs. We found that many neurons in both area TE and perirhinal cortex came to elicit more similar neuronal responses to paired stimuli as learning proceeded. Moreover, these neuronal response changes were learning-dependent and proceeded with an average time course that paralleled learning. This experience-dependent plasticity of sensory representations in the cerebral cortex may underlie the learning of associations between objects.

  11. Learning the association between a context and a target location in infancy.

    Science.gov (United States)

    Bertels, Julie; San Anton, Estibaliz; Gebuis, Titia; Destrebecqz, Arnaud

    2017-07-01

    Extracting the statistical regularities present in the environment is a central learning mechanism in infancy. For instance, infants are able to learn the associations between simultaneously or successively presented visual objects (Fiser & Aslin, ; Kirkham, Slemmer & Johnson, ). The present study extends these results by investigating whether infants can learn the association between a target location and the context in which it is presented. With this aim, we used a visual associative learning procedure inspired by the contextual cuing paradigm, with infants from 8 to 12 months of age. In two experiments, in which we varied the complexity of the stimuli, we first habituated infants to several scenes where the location of a target (a cartoon character) was consistently associated with a context, namely a specific configuration of geometrical shapes. Second, we examined whether infants learned the covariation between the target location and the context by measuring looking times at scenes that either respected or violated the association. In both experiments, results showed that infants learned the target-context associations, as they looked longer at the familiar scenes than at the novel ones. In particular, infants selected clusters of co-occurring contextual shapes and learned the covariation between the target location and this subset. These results support the existence of a powerful and versatile statistical learning mechanism that may influence the orientation of infants' visual attention toward areas of interest in their environment during early developmental stages. A video abstract of this article can be viewed at: https://www.youtube.com/watch?v=9Hm1unyLBn0. © 2016 John Wiley & Sons Ltd.

  12. Modeling the behavioral substrates of associate learning and memory - Adaptive neural models

    Science.gov (United States)

    Lee, Chuen-Chien

    1991-01-01

    Three adaptive single-neuron models based on neural analogies of behavior modification episodes are proposed, which attempt to bridge the gap between psychology and neurophysiology. The proposed models capture the predictive nature of Pavlovian conditioning, which is essential to the theory of adaptive/learning systems. The models learn to anticipate the occurrence of a conditioned response before the presence of a reinforcing stimulus when training is complete. Furthermore, each model can find the most nonredundant and earliest predictor of reinforcement. The behavior of the models accounts for several aspects of basic animal learning phenomena in Pavlovian conditioning beyond previous related models. Computer simulations show how well the models fit empirical data from various animal learning paradigms.

  13. Failing to learn from negative prediction errors: Obesity is associated with alterations in a fundamental neural learning mechanism.

    Science.gov (United States)

    Mathar, David; Neumann, Jane; Villringer, Arno; Horstmann, Annette

    2017-10-01

    Prediction errors (PEs) encode the difference between expected and actual action outcomes in the brain via dopaminergic modulation. Integration of these learning signals ensures efficient behavioral adaptation. Obesity has recently been linked to altered dopaminergic fronto-striatal circuits, thus implying impairments in cognitive domains that rely on its integrity. 28 obese and 30 lean human participants performed an implicit stimulus-response learning paradigm inside an fMRI scanner. Computational modeling and psycho-physiological interaction (PPI) analysis was utilized for assessing PE-related learning and associated functional connectivity. We show that human obesity is associated with insufficient incorporation of negative PEs into behavioral adaptation even in a non-food context, suggesting differences in a fundamental neural learning mechanism. Obese subjects were less efficient in using negative PEs to improve implicit learning performance, despite proper coding of PEs in striatum. We further observed lower functional coupling between ventral striatum and supplementary motor area in obese subjects subsequent to negative PEs. Importantly, strength of functional coupling predicted task performance and negative PE utilization. These findings show that obesity is linked to insufficient behavioral adaptation specifically in response to negative PEs, and to associated alterations in function and connectivity within the fronto-striatal system. Recognition of neural differences as a central characteristic of obesity hopefully paves the way to rethink established intervention strategies: Differential behavioral sensitivity to negative and positive PEs should be considered when designing intervention programs. Measures relying on penalization of unwanted behavior may prove less effective in obese subjects than alternative approaches. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Motor learning in a complex balance task and associated neuroplasticity: a comparison between endurance athletes and nonathletes.

    Science.gov (United States)

    Seidel, Oliver; Carius, Daniel; Kenville, Rouven; Ragert, Patrick

    2017-09-01

    Studies suggested that motor expertise is associated with functional and structural brain alterations, which positively affect sensorimotor performance and learning capabilities. The purpose of the present study was to unravel differences in motor skill learning and associated functional neuroplasticity between endurance athletes (EA) and nonathletes (NA). For this purpose, participants had to perform a multimodal balance task (MBT) training on 2 sessions, which were separated by 1 wk. Before and after MBT training, a static balance task (SBT) had to be performed. MBT-induced functional neuroplasticity and neuromuscular alterations were assessed by means of functional near-infrared spectroscopy (fNIRS) and electromyography (EMG) during SBT performance. We hypothesized that EA would showed superior initial SBT performance and stronger MBT-induced improvements in SBT learning rates compared with NA. On a cortical level, we hypothesized that MBT training would lead to differential learning-dependent functional changes in motor-related brain regions [such as primary motor cortex (M1)] during SBT performance. In fact, EA showed superior initial SBT performance, whereas learning rates did not differ between groups. On a cortical level, fNIRS recordings (time × group interaction) revealed a stronger MBT-induced decrease in left M1 and inferior parietal lobe (IPL) for deoxygenated hemoglobin in EA. Even more interesting, learning rates were correlated with fNIRS changes in right M1/IPL. On the basis of these findings, we provide novel evidence for superior MBT training-induced functional neuroplasticity in highly trained athletes. Future studies should investigate these effects in different sports disciplines to strengthen previous work on experience-dependent neuroplasticity. NEW & NOTEWORTHY Motor expertise is associated with functional/structural brain plasticity. How such neuroplastic reorganization translates into altered motor learning processes remains elusive. We

  15. Strategies to associate memories by unsupervised learning in neural networks

    Science.gov (United States)

    Agnes, E. J.; Mizusaki, B. E. P.; Erichsen, R., Jr.; Brunnet, L. G.

    2013-01-01

    In this work we study the effects of three different strategies to associate memories in a neural network composed by both excitatory and inhibitory spiking neurons, which are randomly connected through recurrent excitatory and inhibitory synapses. The system is intended to store a number of memories, associated to spatial external inputs. The strategies consist in the presentation of the input patterns through trials in: i) ordered sequence; ii) random sequence; iii) clustered sequences. In addition, an order parameter indicating the correlation between the trials' activities is introduced to compute associative memory capacities and the quality of memory retrieval.

  16. Is problem-based learning associated with students’ motivation? A quantitative and qualitative study

    NARCIS (Netherlands)

    M. Wijnen (Marit); S.M.M. Loyens (Sofie); L. Wijnia (Lisette); G. Smeets (Guus); M.J. Kroeze (Maarten); H.T. van der Molen (Henk)

    2017-01-01

    textabstractIn this study, a mixed-method design was employed to investigate the association between a student-centred, problem-based learning (PBL) method and law students’ motivation. Self-determination theory (SDT) states that autonomous motivation, which is associated with higher academic

  17. The Acquisition of Simple Associations as Observed in Color-Word Contingency Learning

    Science.gov (United States)

    Lin, Olivia Y.-H.; MacLeod, Colin M.

    2018-01-01

    Three experiments investigated the learning of simple associations in a color-word contingency task. Participants responded manually to the print colors of 3 words, with each word associated strongly to 1 of the 3 colors and weakly to the other 2 colors. Despite the words being irrelevant, response times to high-contingency stimuli and to…

  18. Learning Curve Characteristics for Caesarean Section Among Associate Clinicians : A Prospective Study from Sierra Leone

    NARCIS (Netherlands)

    Waalewijn, B.P.; van Duinen, A.; Koroma, A. P.; Rijken, M. J.; Elhassein, M.; Bolkan, H. A.

    2017-01-01

    Background: In response to the high maternal mortality ratio, Sierra Leone has adopted an associate clinician postgraduate surgical task-sharing training programme. Little is known about learning curve characteristics for caesarean sections among associate clinicians. The aim of this study is to

  19. Efficient learning of microbial genotype-phenotype association rules.

    Science.gov (United States)

    MacDonald, Norman J; Beiko, Robert G

    2010-08-01

    Finding biologically causative genotype-phenotype associations from whole-genome data is difficult due to the large gene feature space to mine, the potential for interactions among genes and phylogenetic correlations between genomes. Associations within phylogenetically distinct organisms with unusual molecular mechanisms underlying their phenotype may be particularly difficult to assess. We have developed a new genotype-phenotype association approach that uses Classification based on Predictive Association Rules (CPAR), and compare it with NETCAR, a recently published association algorithm. Our implementation of CPAR gave on average slightly higher classification accuracy, with approximately 100 time faster running times. Given the influence of phylogenetic correlations in the extraction of genotype-phenotype association rules, we furthermore propose a novel measure for downweighting the dependence among samples by modeling shared ancestry using conditional mutual information, and demonstrate its complementary nature to traditional mining approaches. Software implemented for this study is available under the Creative Commons Attribution 3.0 license from the author at http://kiwi.cs.dal.ca/Software/PICA

  20. The "proactive" model of learning: Integrative framework for model-free and model-based reinforcement learning utilizing the associative learning-based proactive brain concept.

    Science.gov (United States)

    Zsuga, Judit; Biro, Klara; Papp, Csaba; Tajti, Gabor; Gesztelyi, Rudolf

    2016-02-01

    Reinforcement learning (RL) is a powerful concept underlying forms of associative learning governed by the use of a scalar reward signal, with learning taking place if expectations are violated. RL may be assessed using model-based and model-free approaches. Model-based reinforcement learning involves the amygdala, the hippocampus, and the orbitofrontal cortex (OFC). The model-free system involves the pedunculopontine-tegmental nucleus (PPTgN), the ventral tegmental area (VTA) and the ventral striatum (VS). Based on the functional connectivity of VS, model-free and model based RL systems center on the VS that by integrating model-free signals (received as reward prediction error) and model-based reward related input computes value. Using the concept of reinforcement learning agent we propose that the VS serves as the value function component of the RL agent. Regarding the model utilized for model-based computations we turned to the proactive brain concept, which offers an ubiquitous function for the default network based on its great functional overlap with contextual associative areas. Hence, by means of the default network the brain continuously organizes its environment into context frames enabling the formulation of analogy-based association that are turned into predictions of what to expect. The OFC integrates reward-related information into context frames upon computing reward expectation by compiling stimulus-reward and context-reward information offered by the amygdala and hippocampus, respectively. Furthermore we suggest that the integration of model-based expectations regarding reward into the value signal is further supported by the efferent of the OFC that reach structures canonical for model-free learning (e.g., the PPTgN, VTA, and VS). (c) 2016 APA, all rights reserved).

  1. Reorganization and plastic changes of the human brain associated with skill learning and expertise

    Directory of Open Access Journals (Sweden)

    Yongmin eChang

    2014-02-01

    Full Text Available Novel experience and learning new skills are known as modulators of brain function. Advances in non-invasive brain imaging have provided new insight into structural and functional reorganization associated with skill learning and expertise. Especially, significant imaging evidences come from the domains of sports and music. Data from in vivo imaging studies in sports and music have provided vital information on plausible neural substrates contributing to brain reorganization underlying skill acquisition in humans. This mini review will attempt to take a narrow snapshot of imaging findings demonstrating functional and structural plasticity that mediate skill learning and expertise while identifying converging areas of interest and possible avenues for future research.

  2. SPAN: spike pattern association neuron for learning spatio-temporal sequences

    OpenAIRE

    Mohemmed, A; Schliebs, S; Matsuda, S; Kasabov, N

    2012-01-01

    Spiking Neural Networks (SNN) were shown to be suitable tools for the processing of spatio-temporal information. However, due to their inherent complexity, the formulation of efficient supervised learning algorithms for SNN is difficult and remains an important problem in the research area. This article presents SPAN — a spiking neuron that is able to learn associations of arbitrary spike trains in a supervised fashion allowing the processing of spatio-temporal information encoded in the prec...

  3. Nicotine disrupts safety learning by enhancing fear associated with a safety cue via the dorsal hippocampus.

    Science.gov (United States)

    Connor, David A; Kutlu, Munir G; Gould, Thomas J

    2017-07-01

    Learned safety, a learning process in which a cue becomes associated with the absence of threat, is disrupted in individuals with post-traumatic stress disorder (PTSD). A bi-directional relationship exists between smoking and PTSD and one potential explanation is that nicotine-associated changes in cognition facilitate PTSD emotional dysregulation by disrupting safety associations. Therefore, we investigated whether nicotine would disrupt learned safety by enhancing fear associated with a safety cue. In the present study, C57BL/6 mice were administered acute or chronic nicotine and trained over three days in a differential backward trace conditioning paradigm consisting of five trials of a forward conditioned stimulus (CS)+ (Light) co-terminating with a footshock unconditioned stimulus followed by a backward CS- (Tone) presented 20 s after cessation of the unconditioned stimulus. Summation testing found that acute nicotine disrupted learned safety, but chronic nicotine had no effect. Another group of animals administered acute nicotine showed fear when presented with the backward CS (Light) alone, indicating the formation of a maladaptive fear association with the backward CS. Finally, we investigated the brain regions involved by administering nicotine directly into the dorsal hippocampus, ventral hippocampus, and prelimbic cortex. Infusion of nicotine into the dorsal hippocampus disrupted safety learning.

  4. Fast but fleeting: adaptive motor learning processes associated with aging and cognitive decline.

    Science.gov (United States)

    Trewartha, Kevin M; Garcia, Angeles; Wolpert, Daniel M; Flanagan, J Randall

    2014-10-01

    Motor learning has been shown to depend on multiple interacting learning processes. For example, learning to adapt when moving grasped objects with novel dynamics involves a fast process that adapts and decays quickly-and that has been linked to explicit memory-and a slower process that adapts and decays more gradually. Each process is characterized by a learning rate that controls how strongly motor memory is updated based on experienced errors and a retention factor determining the movement-to-movement decay in motor memory. Here we examined whether fast and slow motor learning processes involved in learning novel dynamics differ between younger and older adults. In addition, we investigated how age-related decline in explicit memory performance influences learning and retention parameters. Although the groups adapted equally well, they did so with markedly different underlying processes. Whereas the groups had similar fast processes, they had different slow processes. Specifically, the older adults exhibited decreased retention in their slow process compared with younger adults. Within the older group, who exhibited considerable variation in explicit memory performance, we found that poor explicit memory was associated with reduced retention in the fast process, as well as the slow process. These findings suggest that explicit memory resources are a determining factor in impairments in the both the fast and slow processes for motor learning but that aging effects on the slow process are independent of explicit memory declines. Copyright © 2014 the authors 0270-6474/14/3413411-11$15.00/0.

  5. Does academic performance or personal growth share a stronger association with learning environment perception?

    Science.gov (United States)

    Colbert-Getz, Jorie M; Tackett, Sean; Wright, Scott M; Shochet, Robert S

    2016-08-28

    This study was conducted to characterize the relative strength of associations of learning environment perception with academic performance and with personal growth. In 2012-2014 second and third year students at Johns Hopkins University School of Medicine completed a learning environment survey and personal growth scale. Hierarchical linear regression analysis was employed to determine if the proportion of variance in learning environment scores accounted for by personal growth was significantly larger than the proportion accounted for by academic performance (course/clerkship grades). The proportion of variance in learning environment scores accounted for by personal growth was larger than the proportion accounted for by academic performance in year 2 [R(2)Δ of 0.09, F(1,175) = 14.99,  p Learning environment scores shared a small amount of variance with academic performance in years 2 and 3.  The amount of variance between learning environment scores and personal growth was small in year 2 and large in year 3. Since supportive learning environments are essential for medical education, future work must determine if enhancing personal growth prior to and during the clerkship year will increase learning environment perception.

  6. Good night, sleep tight: The effects of sleep deprivation on spatial associative learning in zebrafish.

    Science.gov (United States)

    Pinheiro-da-Silva, Jaquelinne; Tran, Steven; Silva, Priscila Fernandes; Luchiari, Ana Carolina

    2017-08-01

    Learning and memory are vital to an animal's survival, and numerous factors can disrupt cognitive performance. Sleep is an evolutionarily conserved physiological process known to be important for the consolidation of learning and memory. The zebrafish has emerged as a powerful model organism sharing organizational and functional characteristics with other vertebrates, providing great translational relevance. In our study, we used a simple spatial associative learning task to quantify the effects of sleep deprivation (partial vs. total) on learning performance in zebrafish, using an animated conspecific shoal image as a reward. Control animals maintained on a regular light:dark cycle were able to acquire the association between the unconditioned and conditioned stimulus, reinforcing zebrafish as a valid and reliable model for appetitive conditioning tasks. Notably, sleep deprivation did not alter the perception of and response to the conspecific image. In contrast, although partial sleep deprivation did not impair cognitive performance, total sleep deprivation significantly impaired performance on the associative learning task. Our results suggest that sleep is important for learning and memory, and that the effects of sleep deprivation on these processes can be investigated in zebrafish. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Addressing the Learning Outcomes and Assessment Methods Associated with Participation in Student Government Associations: A Qualitative Study of California Community Colleges

    Science.gov (United States)

    Nevin, Miles J.

    2017-01-01

    This document analysis synthesized student learning outcomes (SLOs) and assessment methods from a sample of 36 student government associations in the California Community College system. Student learning outcomes were grouped according to "governance, ethical and civic behavior", and "experiential learning functions." Using…

  8. Sleep directly following learning benefits consolidation of spatial associative memory

    NARCIS (Netherlands)

    Talamini, L.M.; Nieuwenhuis, I.L.C.; Takashima, A.

    2008-01-01

    The last decade has brought forth convincing evidence for a role of sleep in non-declarative memory. A similar function of sleep in episodic memory is supported by various correlational studies, but direct evidence is limited. Here we show that cued recall of face–location associations is

  9. Sleep directly following learning benefits consolidation of spatial associative memory

    NARCIS (Netherlands)

    Talamini, L.M.; Nieuwenhuis, I.L.C.; Takashima, A.; Jensen, O.

    2008-01-01

    The last decade has brought forth convincing evidence for a role of sleep in non-declarative memory. A similar function of sleep in episodic memory is supported by various correlational studies, but direct evidence is limited. Here we show that cued recall of face-location associations is

  10. Elemental representation and configural mappings: combining elemental and configural theories of associative learning.

    Science.gov (United States)

    McLaren, I P L; Forrest, C L; McLaren, R P

    2012-09-01

    In this article, we present our first attempt at combining an elemental theory designed to model representation development in an associative system (based on McLaren, Kaye, & Mackintosh, 1989) with a configural theory that models associative learning and memory (McLaren, 1993). After considering the possible advantages of such a combination (and some possible pitfalls), we offer a hybrid model that allows both components to produce the phenomena that they are capable of without introducing unwanted interactions. We then successfully apply the model to a range of phenomena, including latent inhibition, perceptual learning, the Espinet effect, and first- and second-order retrospective revaluation. In some cases, we present new data for comparison with our model's predictions. In all cases, the model replicates the pattern observed in our experimental results. We conclude that this line of development is a promising one for arriving at general theories of associative learning and memory.

  11. Storage and recall capabilities of fuzzy morphological associative memories with adjunction-based learning.

    Science.gov (United States)

    Valle, Marcos Eduardo; Sussner, Peter

    2011-01-01

    We recently employed concepts of mathematical morphology to introduce fuzzy morphological associative memories (FMAMs), a broad class of fuzzy associative memories (FAMs). We observed that many well-known FAM models can be classified as belonging to the class of FMAMs. Moreover, we developed a general learning strategy for FMAMs using the concept of adjunction of mathematical morphology. In this paper, we describe the properties of FMAMs with adjunction-based learning. In particular, we characterize the recall phase of these models. Furthermore, we prove several theorems concerning the storage capacity, noise tolerance, fixed points, and convergence of auto-associative FMAMs. These theorems are corroborated by experimental results concerning the reconstruction of noisy images. Finally, we successfully employ FMAMs with adjunction-based learning in order to implement fuzzy rule-based systems in an application to a time-series prediction problem in industry. Copyright © 2010 Elsevier Ltd. All rights reserved.

  12. Literature mining of protein-residue associations with graph rules learned through distant supervision

    Directory of Open Access Journals (Sweden)

    Ravikumar KE

    2012-10-01

    Full Text Available Abstract Background We propose a method for automatic extraction of protein-specific residue mentions from the biomedical literature. The method searches text for mentions of amino acids at specific sequence positions and attempts to correctly associate each mention with a protein also named in the text. The methods presented in this work will enable improved protein functional site extraction from articles, ultimately supporting protein function prediction. Our method made use of linguistic patterns for identifying the amino acid residue mentions in text. Further, we applied an automated graph-based method to learn syntactic patterns corresponding to protein-residue pairs mentioned in the text. We finally present an approach to automated construction of relevant training and test data using the distant supervision model. Results The performance of the method was assessed by extracting protein-residue relations from a new automatically generated test set of sentences containing high confidence examples found using distant supervision. It achieved a F-measure of 0.84 on automatically created silver corpus and 0.79 on a manually annotated gold data set for this task, outperforming previous methods. Conclusions The primary contributions of this work are to (1 demonstrate the effectiveness of distant supervision for automatic creation of training data for protein-residue relation extraction, substantially reducing the effort and time involved in manual annotation of a data set and (2 show that the graph-based relation extraction approach we used generalizes well to the problem of protein-residue association extraction. This work paves the way towards effective extraction of protein functional residues from the literature.

  13. Literature mining of protein-residue associations with graph rules learned through distant supervision.

    Science.gov (United States)

    Ravikumar, Ke; Liu, Haibin; Cohn, Judith D; Wall, Michael E; Verspoor, Karin

    2012-10-05

    We propose a method for automatic extraction of protein-specific residue mentions from the biomedical literature. The method searches text for mentions of amino acids at specific sequence positions and attempts to correctly associate each mention with a protein also named in the text. The methods presented in this work will enable improved protein functional site extraction from articles, ultimately supporting protein function prediction. Our method made use of linguistic patterns for identifying the amino acid residue mentions in text. Further, we applied an automated graph-based method to learn syntactic patterns corresponding to protein-residue pairs mentioned in the text. We finally present an approach to automated construction of relevant training and test data using the distant supervision model. The performance of the method was assessed by extracting protein-residue relations from a new automatically generated test set of sentences containing high confidence examples found using distant supervision. It achieved a F-measure of 0.84 on automatically created silver corpus and 0.79 on a manually annotated gold data set for this task, outperforming previous methods. The primary contributions of this work are to (1) demonstrate the effectiveness of distant supervision for automatic creation of training data for protein-residue relation extraction, substantially reducing the effort and time involved in manual annotation of a data set and (2) show that the graph-based relation extraction approach we used generalizes well to the problem of protein-residue association extraction. This work paves the way towards effective extraction of protein functional residues from the literature.

  14. BDNF Val66Met Polymorphism Influences Visuomotor Associative Learning and the Sensitivity to Action Observation

    Science.gov (United States)

    Taschereau-Dumouchel, Vincent; Hétu, Sébastien; Michon, Pierre-Emmanuel; Vachon-Presseau, Etienne; Massicotte, Elsa; De Beaumont, Louis; Fecteau, Shirley; Poirier, Judes; Mercier, Catherine; Chagnon, Yvon C.; Jackson, Philip L.

    2016-01-01

    Motor representations in the human mirror neuron system are tuned to respond to specific observed actions. This ability is widely believed to be influenced by genetic factors, but no study has reported a genetic variant affecting this system so far. One possibility is that genetic variants might interact with visuomotor associative learning to configure the system to respond to novel observed actions. In this perspective, we conducted a candidate gene study on the Brain-derived neurotrophic factor (BDNF) Val66Met polymorphism, a genetic variant linked to motor learning in regions of the mirror neuron system, and tested the effect of this polymorphism on motor facilitation and visuomotor associative learning. In a single-pulse TMS study carried on 16 Met (Val/Met and Met/Met) and 16 Val/Val participants selected from a large pool of healthy volunteers, Met participants showed significantly less muscle-specific corticospinal sensitivity during action observation, as well as reduced visuomotor associative learning, compared to Val homozygotes. These results are the first evidence of a genetic variant tuning sensitivity to action observation and bring to light the importance of considering the intricate relation between genetics and associative learning in order to further understand the origin and function of the human mirror neuron system. PMID:27703276

  15. Role of the plasticity-associated transcription factor zif268 in the early phase of instrumental learning.

    Directory of Open Access Journals (Sweden)

    Matthieu Maroteaux

    Full Text Available Gene transcription is essential for learning, but the precise role of transcription factors that control expression of many other genes in specific learning paradigms is yet poorly understood. Zif268 (Krox24/Egr-1 is a transcription factor and an immediate-early gene associated with memory consolidation and reconsolidation, and induced in the striatum after addictive drugs exposure. In contrast, very little is known about its physiological role at early stages of operant learning. We investigated the role of Zif268 in operant conditioning for food. Zif268 expression was increased in all regions of the dorsal striatum and nucleus accumbens in mice subjected to the first session of operant conditioning. In contrast, Zif268 increase in the dorsomedial caudate-putamen and nucleus accumbens core was not detected in yoked mice passively receiving the food reward. This indicates that Zif268 induction in these structures is linked to experiencing or learning contingency, but not to reward delivery. When the task was learned (5 sessions, Zif268 induction disappeared in the nucleus accumbens and decreased in the medial caudate-putamen, whereas it remained high in the lateral caudate-putamen, previously implicated in habit formation. In transgenic mice expressing green fluorescent protein (GFP in the striatonigral neurons, Zif268 induction occured after the first training session in both GFP-positive and negative neurons indicating an enhanced Zif268 expression in both striatonigral and striatopallidal neurons. Mutant mice lacking Zif268 expression obtained less rewards, but displayed a normal discrimination between reinforced and non-reinforced targets, and an unaltered approach to food delivery box. In addition, their motivation to obtain food rewards, evaluated in a progressive ratio schedule, was blunted. In conclusion, Zif268 participates in the processes underlying performance and motivation to execute food-conditioned instrumental task.

  16. Associative learning changes cross-modal representations in the gustatory cortex.

    Science.gov (United States)

    Vincis, Roberto; Fontanini, Alfredo

    2016-08-30

    A growing body of literature has demonstrated that primary sensory cortices are not exclusively unimodal, but can respond to stimuli of different sensory modalities. However, several questions concerning the neural representation of cross-modal stimuli remain open. Indeed, it is poorly understood if cross-modal stimuli evoke unique or overlapping representations in a primary sensory cortex and whether learning can modulate these representations. Here we recorded single unit responses to auditory, visual, somatosensory, and olfactory stimuli in the gustatory cortex (GC) of alert rats before and after associative learning. We found that, in untrained rats, the majority of GC neurons were modulated by a single modality. Upon learning, both prevalence of cross-modal responsive neurons and their breadth of tuning increased, leading to a greater overlap of representations. Altogether, our results show that the gustatory cortex represents cross-modal stimuli according to their sensory identity, and that learning changes the overlap of cross-modal representations.

  17. Memory and learning sequelae in long-term survivors of acute lymphoblastic leukemia: Association with attention deficits

    International Nuclear Information System (INIS)

    Brouwers, P.; Poplack, D.

    1990-01-01

    A systematic study of verbal and nonverbal memory and learning was undertaken in long-term survivors of acute lymphoblastic leukemia to assess the incidence and pattern of impairments and to determine the relationship between these deficits and computed tomography (CT) brain scan abnormalities. Twenty-three children who had received cranial irradiation (2,400 cGy) and intrathecal chemotherapy as central nervous system (CNS) preventive therapy and who were off all therapy for at least 4 years were evaluated. On the basis of their CT brain scan findings, patients were divided into three groups: those with intracerebral calcifications (n = 5), those with cortical atrophy (n = 8), and those with normal CT findings (n = 10). Significant deficits in verbal memory (p less than 0.025) and verbal learning (p less than 0.05) were observed that were associated with the presence and type of CT brain scan abnormalities; the greatest impairments were observed in patients with calcifications. No significant differences between CT scan groups were found for nonverbal memory and learning. Previous evaluation of attentional processing in these patients using reaction time tests had revealed the presence of deficits primarily in the ability to sustain attention. Combining those data with findings from the present study showed that memory impairments, particularly those in short-term memory, were primarily attributable to an underlying attentional defect that affect the encoding stage of memory processing

  18. The declarative system in children with specific language impairment: a comparison of meaningful and meaningless auditory-visual paired associate learning.

    Science.gov (United States)

    Bishop, Dorothy V M; Hsu, Hsinjen Julie

    2015-01-01

    It has been proposed that children with Specific Language Impairment (SLI) have a selective deficit in procedural learning, with relatively spared declarative learning. In previous studies we and others confirmed deficits in procedural learning of sequences, using both verbal and nonverbal materials. Here we studied the same children using a task that implicates the declarative system, auditory-visual paired associate learning. There were parallel tasks for verbal materials (vocabulary learning) and nonverbal materials (meaningless patterns and sounds). Participants were 28 children with SLI aged 7-11 years, 28 younger typically-developing children matched for raw scores on a test of receptive grammar, and 20 typically-developing children matched on chronological age. Children were given four sessions of paired-associate training using a computer game adopting an errorless learning procedure, during which they had to select a picture from an array of four to match a heard stimulus. In each session they did both vocabulary training, where the items were eight names and pictures of rare animals, and nonverbal training, where stimuli were eight visual patterns paired with complex nonverbal sounds. A total of 96 trials of each type was presented over four days. In all groups, accuracy improved across the four sessions for both types of material. For the vocabulary task, the age-matched control group outperformed the other two groups in the starting level of performance, whereas for the nonverbal paired-associate task, there were no reliable differences between groups. In both tasks, rate of learning was comparable for all three groups. These results are consistent with the Procedural Deficit Hypothesis of SLI, in finding spared declarative learning on a nonverbal auditory-visual paired associate task. On the verbal version of the task, the SLI group had a deficit in learning relative to age-matched controls, which was evident on the first block in the first session

  19. Multi-label Learning for Detection of CME-Associated Phenomena

    Science.gov (United States)

    Yang, Y. H.; Tian, H. M.; Peng, B.; Li, T. R.; Xie, Z. X.

    2017-09-01

    Coronal mass ejections (CMEs) are considered as one of the driving sources of space weather. They are usually associated with many physical phenomena, e.g. flares, coronal dimmings, and sigmoids. To detect these phenomena, traditional supervised-learning methods assumed that at most one event occurred in a CME; therefore each CME instance is associated with a single label and the phenomenon is processed in isolation. This simplifying assumption does not fit well, as CMEs might have multiple events simultaneously. We propose to detect multiple CME-associated events by multi-label learning methods. With the data available from the Atmospheric Imaging Assembly (AIA) and the Large Angle and Spectrometric Coronagraph (LASCO), texture features representing the events are extracted from all of the associated and not-associated CMEs and converted into feature vectors for multi-label learning use. Then a function is learned to predict the proper label sets for CMEs, such that eight events, i.e. coronal dimming, coronal hole, coronal jet, coronal wave, filament, filament eruption, flare, and sigmoid, are detected explicitly. To test the proposed detection algorithm, we adopt the four-fold cross-validation strategy on a set of 551 labeled CMEs from AIA. Experimental results demonstrate the good performance of the multi-label classification methods in terms of test error.

  20. Bayesian methods for addressing long-standing problems in associative learning: The case of PREE.

    Science.gov (United States)

    Blanco, Fernando; Moris, Joaquín

    2017-07-20

    Most associative models typically assume that learning can be understood as a gradual change in associative strength that captures the situation into one single parameter, or representational state. We will call this view single-state learning. However, there is ample evidence showing that under many circumstances different relationships that share features can be learned independently, and animals can quickly switch between expressing one or another. We will call this multiple-state learning. Theoretically, it is understudied because it needs a different data analysis approach from those usually employed. In this paper, we present a Bayesian model of the Partial Reinforcement Extinction Effect (PREE) that can test the predictions of the multiple-state view. This implies estimating the moment of change in the responses (from the acquisition to the extinction performance), both at the individual and at the group levels. We used this model to analyze data from a PREE experiment with three levels of reinforcement during acquisition (100%, 75% and 50%). We found differences in the estimated moment of switch between states during extinction, so that it was delayed after leaner partial reinforcement schedules. The finding is compatible with the multiple-state view. It is the first time, to our knowledge, that the predictions from the multiple-state view are tested directly. The paper also aims to show the benefits that Bayesian methods can bring to the associative learning field.

  1. Distinct roles of the RasGAP family proteins in C. elegans associative learning and memory.

    Science.gov (United States)

    Gyurkó, M Dávid; Csermely, Péter; Sőti, Csaba; Steták, Attila

    2015-10-15

    The Ras GTPase activating proteins (RasGAPs) are regulators of the conserved Ras/MAPK pathway. Various roles of some of the RasGAPs in learning and memory have been reported in different model systems, yet, there is no comprehensive study to characterize all gap genes in any organism. Here, using reverse genetics and neurobehavioural tests, we studied the role of all known genes of the rasgap family in C. elegans in associative learning and memory. We demonstrated that their proteins are implicated in different parts of the learning and memory processes. We show that gap-1 contribute redundantly with gap-3 to the chemosensation of volatile compounds, gap-1 plays a major role in associative learning, while gap-2 and gap-3 are predominantly required for short- and long-term associative memory. Our results also suggest that the C. elegans Ras orthologue let-60 is involved in multiple processes during learning and memory. Thus, we show that the different classes of RasGAP proteins are all involved in cognitive function and their complex interplay ensures the proper formation and storage of novel information in C. elegans.

  2. Differential contribution of hippocampal subfields to components of associative taste learning.

    Science.gov (United States)

    Chinnakkaruppan, Adaikkan; Wintzer, Marie E; McHugh, Thomas J; Rosenblum, Kobi

    2014-08-13

    The ability to associate the consumption of a taste with its positive or negative consequences is fundamental to survival and influences the behavior of species ranging from invertebrate to human. As a result, for both research and clinical reasons, there has been a great effort to understand the neuronal circuits, as well as the cellular and molecular mechanisms, underlying taste learning. From a neuroanatomical perspective, the contributions of the cortex and amygdala are well documented; however, the literature is riddled with conflicting results regarding the role of the hippocampus in different facets of taste learning. Here, we use conditional genetics in mice to block NMDA receptor-dependent plasticity individually in each of the three major hippocampal subfields, CA1, CA3, and the dentate gyrus, via deletion of the NR1 subunit. Across the CA1, CA3, and dentate gyrus NR1 knock-out lines, we uncover a pattern of differential deficits that establish the dispensability of hippocampal plasticity in incidental taste learning, the requirement of CA1 plasticity for associative taste learning, and a specific requirement for plasticity in the dentate gyrus when there is a long temporal gap between the taste and its outcome. Together, these data establish that the hippocampus is involved in associative taste learning and suggest an episodic component to this type of memory. Copyright © 2014 the authors 0270-6474/14/3411007-09$15.00/0.

  3. Adult Hippocampal Neurogenesis Modulates Fear Learning through Associative and Nonassociative Mechanisms

    Science.gov (United States)

    Seo, Dong-oh; Carillo, Mary Ann; Chih-Hsiung Lim, Sean; Tanaka, Kenji F.

    2015-01-01

    Adult hippocampal neurogenesis is believed to support hippocampus-dependent learning and emotional regulation. These putative functions of adult neurogenesis have typically been studied in isolation, and little is known about how they interact to produce adaptive behavior. We used trace fear conditioning as a model system to elucidate mechanisms through which adult hippocampal neurogenesis modulates processing of aversive experience. To achieve a specific ablation of neurogenesis, we generated transgenic mice that express herpes simplex virus thymidine kinase specifically in neural progenitors and immature neurons. Intracerebroventricular injection of the prodrug ganciclovir caused a robust suppression of neurogenesis without suppressing gliogenesis. Neurogenesis ablation via this method or targeted x-irradiation caused an increase in context conditioning in trace but not delay fear conditioning. Data suggest that this phenotype represents opposing effects of neurogenesis ablation on associative and nonassociative components of fear learning. Arrest of neurogenesis sensitizes mice to nonassociative effects of fear conditioning, as evidenced by increased anxiety-like behavior in the open field after (but not in the absence of) fear conditioning. In addition, arrest of neurogenesis impairs associative trace conditioning, but this impairment can be masked by nonassociative fear. The results suggest that adult neurogenesis modulates emotional learning via two distinct but opposing mechanisms: it supports associative trace conditioning while also buffering against the generalized fear and anxiety caused by fear conditioning. SIGNIFICANCE STATEMENT The role of adult hippocampal neurogenesis in fear learning is controversial, with some studies suggesting neurogenesis is needed for aspects of fear learning and others suggesting it is dispensable. We generated transgenic mice in which neural progenitors can be selectively and inducibly ablated. Our data suggest that adult

  4. Dental Students' Study Habits in Flipped/Blended Classrooms and Their Association with Active Learning Practices.

    Science.gov (United States)

    Gadbury-Amyot, Cynthia C; Redford, Gloria J; Bohaty, Brenda S

    2017-12-01

    In recognition of the importance for dental education programs to take a student-centered approach in which students are encouraged to take responsibility for their learning, a pediatric dentistry course redesign aimed at promoting greater active and self-directed learning was implemented at one U.S. dental school. The aim of this study was to examine the association between the students' self-reported study habits and active learning practices necessary for meaningful learning in the flipped/blended classroom. A convenience sample of two classes of second-year dental students in spring 2014 (SP14, n=106) and spring 2015 (SP15, n=106) was invited to participate in the study. Of the SP14 students, 84 participated, for a response rate of 79%; of the SP15 students, 94 participated, for a response rate of 87%. Students' self-reported responses to questions about study strategies with the prerecorded lecture materials and assigned reading materials were examined. Non-parametric analyses resulted in a cohort effect, so data are reported by class. In the SP15 class, 72% reported watching all/more than half of the prerecorded lectures versus 62% of the SP14 class, with a majority watching more than one lecture per week. In the SP15 cohort, 68% used active learning strategies when watching the lectures versus 58.3% of the SP14 cohort. The time of day preferred by the majority of both cohorts for interacting with course materials was 7-11 pm. Both SP14 and SP15 students reported being unlikely to read assigned materials prior to coming to class. Overall, the course redesign appeared to engage students in self-directed active learning. However, the degree to which active learning practices were taking place to achieve meaningful learning was questionable given students' self-reported study strategies. More work is needed to examine strategies for promoting study practices that will lead to meaningful learning.

  5. Quantum-Inspired Multidirectional Associative Memory With a Self-Convergent Iterative Learning.

    Science.gov (United States)

    Masuyama, Naoki; Loo, Chu Kiong; Seera, Manjeevan; Kubota, Naoyuki

    2018-04-01

    Quantum-inspired computing is an emerging research area, which has significantly improved the capabilities of conventional algorithms. In general, quantum-inspired hopfield associative memory (QHAM) has demonstrated quantum information processing in neural structures. This has resulted in an exponential increase in storage capacity while explaining the extensive memory, and it has the potential to illustrate the dynamics of neurons in the human brain when viewed from quantum mechanics perspective although the application of QHAM is limited as an autoassociation. We introduce a quantum-inspired multidirectional associative memory (QMAM) with a one-shot learning model, and QMAM with a self-convergent iterative learning model (IQMAM) based on QHAM in this paper. The self-convergent iterative learning enables the network to progressively develop a resonance state, from inputs to outputs. The simulation experiments demonstrate the advantages of QMAM and IQMAM, especially the stability to recall reliability.

  6. Electrophysiological CNS-processes related to associative learning in humans.

    Science.gov (United States)

    Christoffersen, Gert R J; Schachtman, Todd R

    2016-01-01

    The neurophysiology of human associative memory has been studied with electroencephalographic techniques since the 1930s. This research has revealed that different types of electrophysiological processes in the human brain can be modified by conditioning: sensory evoked potentials, sensory induced gamma-band activity, periods of frequency-specific waves (alpha and beta waves, the sensorimotor rhythm and the mu-rhythm) and slow cortical potentials. Conditioning of these processes has been studied in experiments that either use operant conditioning or repeated contingent pairings of conditioned and unconditioned stimuli (classical conditioning). In operant conditioning, the appearance of a specific brain process is paired with an external stimulus (neurofeedback) and the feedback enables subjects to obtain varying degrees of control of the CNS-process. Such acquired self-regulation of brain activity has found practical uses for instance in the amelioration of epileptic seizures, Autism Spectrum Disorders (ASD) and Attention Deficit Hyperactivity Disorder (ADHD). It has also provided communicative means of assistance for tetraplegic patients through the use of brain computer interfaces. Both extra and intracortically recorded signals have been coupled with contingent external feedback. It is the aim for this review to summarize essential results on all types of electromagnetic brain processes that have been modified by classical or operant conditioning. The results are organized according to type of conditioned EEG-process, type of conditioning, and sensory modalities of the conditioning stimuli. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Coordinating associative and ecological accounts of learning in the garden snail Cornu aspersum.

    Science.gov (United States)

    Loy, I; Álvarez, B; Strempler-Rubio, E C; Rodríguez, M

    2017-06-01

    Pavlovian conditioning of tentacle lowering in the snail, Cornu aspersum, as an instance of associative learning, has proven effective to show evidence of paradigmatic associative phenomena (e.g., blocking) explained by current models of conditioning. Nevertheless, the available literature questions the biological function of the conditioned response (i.e., tentacle lowering) in snails since no advantages in terms of food finding had been observed. Ecological accounts of learning claim that learning abilities contribute to the adaptation to the environmental demands, and there is experimental evidence supporting this in several species (e.g., grasshoppers, fish, or antlions). However, there is a lack of evidence in snails, which is surprising given that the conditioned response of tentacle lowering is a robust finding that fits in with several predictions of associative learning theory (e.g., blocking or conditioned inhibition). The goal of this manuscript was to test whether food detection is affected by prior experience with the food, distance, and conditioning. We found that prior experience with a food source is necessary for snails to locate the same food item; that the optimal distance to test for food detection is between 5 and 7cm and that snails seem to use different food searching strategies after conditioning depending on the stimuli that are present. The data provided constitute a small contribution to the vindication of a greater coordination between the fruitful research tool provided by the associative account of learning and the evolutionary vocation of the ecological approach of learning. Copyright © 2017. Published by Elsevier B.V.

  8. Fatores Associados à Realização de Cesárea em Primíparas com uma Cesárea Anterior Factors Associated with Cesarean Section in Primipara Women with One Previous Cesarean Section

    Directory of Open Access Journals (Sweden)

    José Guilherme Cecatti

    2000-04-01

    Full Text Available Objetivo: avaliar a via de parto em um grupo de gestantes primíparas de baixa renda com uma cesárea anterior e os fatores associados à repetição da cesárea no segundo parto. Pacientes e Métodos: realizou-se um estudo caso-controle com 356 gestantes atendidas de janeiro de 1993 a janeiro de 1996 na Maternidade do CAISM/UNICAMP. Constituíram os casos as 153 gestantes que tiveram o segundo parto por cesárea, e os controles, as 203 que tiveram o segundo parto vaginal. Para a análise utilizaram-se médias, desvio padrão, teste t de Student, teste de Mann-Whitney, chi² e "odds ratio" (OR e IC 95% para cada possível fator associado à realização de cesárea no segundo parto. Resultados: a via do segundo parto foi vaginal em 57% das vezes. Dentre as diversas variáveis estudadas, as que mostraram estar significativamente associadas à realização de cesárea no segundo parto foram: maior idade materna (para mulheres com 35 anos ou mais, OR = 16,4, antecedente de abortamento (OR = 2,09, indução do trabalho de parto (OR = 3,83, rotura prematura de membranas (OR = 2 ,83, a não-realização de analgesia durante o período de dilatação (OR = 5,3, o diagnóstico de algum sinal de vitalidade fetal alterada (OR = 2,7 e a ocorrência do parto à tarde (OR = 1,92. Conclusões: os resultados indicam que os fatores associados à repetição de cesárea em mulheres com uma cicatriz de cesárea nesta população são predominantemente médicos, mas há a possibilidade de se proporem intervenções dirigidas a diminuir o índice de repetição de cesáreas.Purpose: to evaluate the route of delivery in a group of low-income primipara pregnant women with a previous cesarean section, and the factors associated with the repetition of the cesarean section on the second delivery. Patients and Methods: it was a case-control study including 356 women who were assisted at the Maternity of CAISM/UNICAMP during the period between January 1993 and January

  9. Foundational Aspects of Classroom Relations: Associations between Teachers' Immediacy Behaviours, Classroom Democracy, Class Identification and Learning

    Science.gov (United States)

    Kwitonda, Jean Claude

    2017-01-01

    This study focused on foundational aspects of classroom relations. Specifically, relationships between teachers' immediacy (interpersonal) behaviours, classroom democracy, identification and learning were considered. Previous work suggests that these variables can be used as a foundation to shape classroom climate, culture and learning outcomes…

  10. Functional contributions and interactions between the human hippocampus and subregions of the striatum during arbitrary associative learning and memory

    Science.gov (United States)

    Mattfeld, Aaron T.; Stark, Craig E. L.

    2015-01-01

    The hippocampus and striatum are thought to have different functional roles in learning and memory. It is unknown under what experimental conditions their contributions are dissimilar or converge, and the extent to which they interact over the course of learning. In order to evaluate both the functional contributions of as well as the interactions between the human hippocampus and striatum, the present study used high-resolution functional magnetic resonance imaging (fMRI) and variations of a conditional visuomotor associative learning task that either taxed arbitrary associative learning (Experiment 1) or stimulus-response learning (Experiment 2). In the first experiment we observed changes in activity in the hippocampus and anterior caudate that reflect differences between the two regions consistent with distinct computational principles. In the second experiment we observed activity in the putamen that reflected content specific representations during the learning of arbitrary conditional visuomotor associations. In both experiments the hippocampus and ventral striatum demonstrated dynamic functional coupling during the learning of new arbitrary associations, but not during retrieval of well-learned arbitrary associations using control variants of the tasks that did not preferentially tax one system versus the other. These findings suggest that both the hippocampus and subregions of the dorsal striatum contribute uniquely to the learning of arbitrary associations while the hippocampus and ventral striatum interact over the course of learning. PMID:25560298

  11. Team learning and its association with the implementation of competence-based education

    NARCIS (Netherlands)

    Wijnia, L.; Kunst, E.M.; van Woerkom, M.; Poell, R.F.

    2016-01-01

    Competence-based education (CBE) is the leading paradigm for education reform of Vocational Education and Training in European countries. This study addresses the association of collective team identification, task interdependence, team learning, and team size, with the implementation of CBE (N =

  12. Learning Outcomes Associated with Classroom Implementation of a Biotechnology-Themed Video Game

    Science.gov (United States)

    Barko, Tim; Sadler, Troy D.

    2013-01-01

    The educational video game Mission Biotech provides a virtual experience for students in learning biotechnology materials and tools. This study explores the use of Mission Biotech and the associated curriculum by three high school teachers and their students. All three classes demonstrated gains on a curriculum-aligned test of science content.…

  13. Do Psychology Department Mission Statements Reflect the American Psychological Association Undergraduate Learning Goals?

    Science.gov (United States)

    Warchal, Judith R.; Ruiz, Ana I.; You, Di

    2017-01-01

    This study focuses on the inclusion of the American Psychological Association's learning goals in the mission statements of undergraduate psychology programs across the US. We reviewed the mission statements available on websites for 1336 psychology programs listed in the Carnegie classification. Results of a content analysis revealed that of the…

  14. Are Approaches to Learning in Kindergarten Associated with Academic and Social Competence Similarly?

    Science.gov (United States)

    Razza, Rachel A.; Martin, Anne; Brooks-Gunn, Jeanne

    2015-01-01

    Background: Approaches to learning (ATL) is a key domain of school readiness with important implications for children's academic trajectories. Interestingly, however, the impact of early ATL on children's social competence has not been examined. Objective: This study examines associations between children's ATL at age 5 and academic achievement…

  15. Children Learn Spurious Associations in Their Math Textbooks: Examples from Fraction Arithmetic

    Science.gov (United States)

    Braithwaite, David W.; Siegler, Robert S.

    2018-01-01

    Fraction arithmetic is among the most important and difficult topics children encounter in elementary and middle school mathematics. Braithwaite, Pyke, and Siegler (2017) hypothesized that difficulties learning fraction arithmetic often reflect reliance on associative knowledge--rather than understanding of mathematical concepts and procedures--to…

  16. History and Culture of Alara--The Action Learning and Action Research Association

    Science.gov (United States)

    Zuber-Skerritt, Ortrun; Passfield, Ron

    2016-01-01

    As co-founders of the Action Learning and Action Research Association (ALARA), we tell the story of this international network organisation through our personal experience. Our history traces the evolution of ALARA from origins at the first World Congress in 1990 in Brisbane, Australia, through development over two and a half decades, to its…

  17. Association of prenatal alcohol exposure with behavioral and learning problems in early adolescence.

    Science.gov (United States)

    Olson, H C; Streissguth, A P; Sampson, P D; Barr, H M; Bookstein, F L; Thiede, K

    1997-09-01

    To examine the association of moderate levels of prenatal alcohol exposure with learning and behavior in early adolescence. A population-based cohort of 464 children were followed longitudinally from birth to age 14 years. Alcohol exposure was assessed via in-depth maternal self-report in the fifth month of pregnancy. At age 14, learning and behavior were assessed with multiple measures, tapping parent, teenager, and psychologist viewpoints, drawn from adolescent laboratory examination and parent phone interview. The underlying pattern of association between prenatal alcohol and adolescent outcome was detected using partial least-squares statistical techniques; confounding factors were dealt with by regression methods. Analyses revealed a statistically significant, subtle relationship between greater prenatal alcohol use and increased behavior/learning difficulties during adolescence, even after accounting for other developmental influences. "Binge" maternal drinking and exposure early in pregnancy were associated with a profile of adolescent antisocial behavior, school problems, and self-perceived learning difficulties. Fetal alcohol exposure (even at "social drinking" levels) is associated with developmental difficulties in adolescence that are consistent with problems seen earlier in life. Clinicians should understand the potential role prenatal alcohol exposure plays in behavioral and cognitive problems.

  18. Associative Learning Predicts Intelligence above and beyond Working Memory and Processing Speed

    Science.gov (United States)

    Kaufman, Scott Barry; DeYoung, Colin G; Gray, Jeremy R.; Brown, Jamie; Mackintosh, Nicholas

    2009-01-01

    Recent evidence suggests the existence of multiple cognitive mechanisms that support the general cognitive ability factor (g). Working memory and processing speed are the two best established candidate mechanisms. Relatively little attention has been given to the possibility that associative learning is an additional mechanism contributing to g.…

  19. Learning Processes Associated with Panic-Related Symptoms in Families with and without Panic Disordered Mothers

    Science.gov (United States)

    de Albuquerque, Jiske E. G.; Munsch, Simone; Margraf, Jurgen; Schneider, Silvia

    2013-01-01

    The present study compared learning processes associated with panic-related symptoms in families with and without panic disordered mothers. Using a multi-informant approach, 86 mothers [of whom 58 had a primary diagnosis of panic disorder (PD)], their partners and teenage children (mean age, 16.67 years) reported about parents' behavior (modeling…

  20. A World of Learning: Practical Manual. Enhancing the Multiplier Effect of the Associated Schools Project.

    Science.gov (United States)

    United Nations Educational, Scientific, and Cultural Organization, Paris (France).

    This manual presents the major lessons learned about how national authorities, individual institutions, and individual educators can work to increase the impact of the Associated Schools Project (ASP) schools and spread it to other parts of the educational system. ASP is a project of the United Nations Educational, Scientific and Cultural…

  1. Falling into LINE: School Strategies for Overcoming Challenges Associated with Learning in Natural Environments (LINE)

    Science.gov (United States)

    Edwards-Jones, Andrew; Waite, Sue; Passy, Rowena

    2018-01-01

    As the benefits of outdoor learning have become of increasing interest to the education sector, so the importance of understanding and overcoming challenges associated with this pedagogy has gained greater significance. The Natural Connections Demonstration Project recruited primary, secondary, and special schools across south-west England with a…

  2. Physical activity and sedentary behavior associated with learning outcomes and cognition in adult distance learners

    NARCIS (Netherlands)

    Gijselaers, Jérôme; De Groot, Renate; Kirschner, Paul A.

    2013-01-01

    Gijselaers, H. J. M., De Groot, R. H. M., & Kirschner, P. A. (2013, 7 November). Physical activity and sedentary behavior associated with learning outcomes and cognition in adult distance learners. Paper presentation at the ICO [Interuniversity Center for Educational Research] National Fall School,

  3. Rapid Associative Learning and Stable Long-Term Memory in the Squid Euprymna scolopes.

    Science.gov (United States)

    Zepeda, Emily A; Veline, Robert J; Crook, Robyn J

    2017-06-01

    Learning and memory in cephalopod molluscs have received intensive study because of cephalopods' complex behavioral repertoire and relatively accessible nervous systems. While most of this research has been conducted using octopus and cuttlefish species, there has been relatively little work on squid. Euprymna scolopes Berry, 1913, a sepiolid squid, is a promising model for further exploration of cephalopod cognition. These small squid have been studied in detail for their symbiotic relationship with bioluminescent bacteria, and their short generation time and successful captive breeding through multiple generations make them appealing models for neurobiological research. However, little is known about their behavior or cognitive ability. Using the well-established "prawn-in-the-tube" assay of learning and memory, we show that within a single 10-min trial E. scolopes learns to inhibit its predatory behavior, and after three trials it can retain this memory for at least 12 d. Rapid learning and very long-term retention were apparent under two different training schedules. To our knowledge, this study is the first demonstration of learning and memory in this species as well as the first demonstration of associative learning in any squid.

  4. Nicotinic modulation of hippocampal cell signaling and associated effects on learning and memory.

    Science.gov (United States)

    Kutlu, Munir Gunes; Gould, Thomas J

    2016-03-01

    The hippocampus is a key brain structure involved in synaptic plasticity associated with long-term declarative memory formation. Importantly, nicotine and activation of nicotinic acetylcholine receptors (nAChRs) can alter hippocampal plasticity and these changes may occur through modulation of hippocampal kinases and transcription factors. Hippocampal kinases such as cAMP-dependent protein kinase (PKA), calcium/calmodulin-dependent protein kinases (CAMKs), extracellular signal-regulated kinases 1 and 2 (ERK1/2), and c-jun N-terminal kinase 1 (JNK1), and the transcription factor cAMP-response element-binding protein (CREB) that are activated either directly or indirectly by nicotine may modulate hippocampal plasticity and in parallel hippocampus-dependent learning and memory. Evidence suggests that nicotine may alter hippocampus-dependent learning by changing the time and magnitude of activation of kinases and transcription factors normally involved in learning and by recruiting additional cell signaling molecules. Understanding how nicotine alters learning and memory will advance basic understanding of the neural substrates of learning and aid in understanding mental disorders that involve cognitive and learning deficits. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Finding patterns and learning words: Infant phonotactic knowledge is associated with vocabulary size.

    Science.gov (United States)

    Graf Estes, Katharine; Gluck, Stephanie Chen-Wu; Grimm, Kevin J

    2016-06-01

    Native language statistical regularities about allowable phoneme combinations (i.e., phonotactic patterns) may provide learners with cues to support word learning. The current research investigated the association between infants' native language phonotactic knowledge and their word learning progress, as measured by vocabulary size. In the experiment, 19-month-old infants listened to a corpus of nonce words that contained novel phonotactic patterns. All words began with "illegal" consonant clusters that cannot occur in native (English) words. The rationale for the task was that infants with fragile phonotactic knowledge should exhibit stronger learning of the novel illegal phonotactic patterns than infants with robust phonotactic knowledge. We found that infants with smaller vocabularies showed stronger phonotactic learning than infants with larger vocabularies even after accounting for general cognition. We propose that learning about native language structure may promote vocabulary development by providing a foundation for word learning; infants with smaller vocabularies may have weaker support from phonotactics than infants with larger vocabularies. Furthermore, stored vocabulary knowledge may promote the detection of phonotactic patterns even during infancy. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Association of Medical School Pediatric Department Chairs Principles of Lifelong Learning in Pediatric Medicine.

    Science.gov (United States)

    Opipari, Valerie P; Daniels, Stephen R; Wilmott, Robert W; Jacobs, Richard F

    2016-11-01

    Pediatric general and subspecialty care requires continuous effort to maintain knowledge and competencies in clinical practice. Equally important are efforts by investigators and educators to maintain knowledge and competencies in the conduct of research and training. The Association of Medical School Pediatric Department Chairs initiated a survey in July 2015 to define principles of lifelong learning in pediatric medicine and determine the approaches and strategies used by chairs to assess knowledge and competence across the care, research, and teaching missions. A total of 101 of 142 chairs (71%) completed the survey. Six of 7 proposed principles were endorsed by 84% to 96% of Association of Medical School Pediatric Department Chairs members. The focus areas included individual accountability, individually relevant activities, use of evidence-based guidelines/national standards, gaining cognitive expertise, learning as a continuous effort, affordability, and focus on individual understanding. The chairs endorsed a requirement for evidence of lifelong learning, competence, and compliance by all faculty members in clinical (n = 89 [88%]), research (n = 63 [62%]), and educational (n = 85 [84%]) practice. The survey identified the strategies to assess lifelong learning and faculty competence and compliance in clinical, research, and educational roles. Across missions, chairs endorsed an expectation for individual responsibility supplemented by formal evaluation practices and institutional and regulatory office oversight. While chairs endorsed an important role for the American Board of Pediatrics in assessing and verifying lifelong learning, knowledge, and competence in general and specialty certification, most (n = 91 [90%]) endorsed a need to revise current board requirements to better emphasize closing gaps in knowledge and using approaches that are evidence-based. This study provides the perspectives of pediatric department chairs on principles

  7. Retrospective analysis of the learning curve associated with laparoscopic ovariectomy in dogs and associated perioperative complication rates.

    Science.gov (United States)

    Pope, Juliet Frances Anne; Knowles, Toby Grahame

    2014-08-01

    To assess the learning curve associated with laparoscopic ovariectomy (LOE) in 618 dogs and to report perioperative complication rates. Case series. Dogs (n = 618). Data retrieved from the medical records of bitches admitted for LOE over 42 months included date of surgery, breed, weight (kg), age (months), surgeon, suture material used, intraoperative complications and postoperative complications. Each LOE was defined as "successful" or "unsuccessful" by the absence or presence of an intraoperative complication and "failure" rate described using a CUSUM technique. Follow-up time ranged from 152 to 1,435 days (median, 737 days). Intraoperative complications occurred in 10 dogs (1.6%) and included: splenic laceration (6 dogs; 1%), urinary bladder perforation (3 dogs; 0.5%), and subcutaneous emphysema (1 dog; 0.2%). Postoperative complications occurred in 99 dogs (16%) and included: incisional inflammation treated with antibiotics (87 dogs [14%]; 96/1,854 incisions; 5.1%), incisional seroma (5 dogs [0.8%]; 5/1,854 incisions, 0.3%), incisional hernia (4 dogs [0.6%]; 4/1,854 incisions, 0.2%), and ovarian remnant syndrome (3 dogs; 0.5%). CUSUM charts indicated an initial "learning curve" of ∼80 LOE. LOE is a technique with an initial learning curve but once surgical proficiency is reached after ∼80 procedures then intraoperative complication rates associated with the procedure can be low. © Copyright 2014 by The American College of Veterinary Surgeons.

  8. Positive and negative feedback learning and associated dopamine and serotonin transporter binding after methamphetamine.

    Science.gov (United States)

    Stolyarova, Alexandra; O'Dell, Steve J; Marshall, John F; Izquierdo, Alicia

    2014-09-01

    Learning from mistakes and prospectively adjusting behavior in response to reward feedback is an important facet of performance monitoring. Dopamine (DA) pathways play an important role in feedback learning and a growing literature has also emerged on the importance of serotonin (5HT) in reward learning, particularly during punishment or reward omission (negative feedback). Cognitive impairments resulting from psychostimulant exposure may arise from altered patterns in feedback learning, which in turn may be modulated by DA and 5HT transmission. We analyzed long-term, off-drug changes in learning from positive and negative feedback and associated striatal DA transporter (DAT) and frontocortical 5HT transporter (SERT) binding in rats pretreated with methamphetamine (mAMPH). Specifically, we assessed the reversal phase of pairwise visual discrimination learning in rats receiving single dose- (mAMPHsingle) vs. escalating-dose exposure (mAMPHescal). Using fine-grained trial-by-trial analyses, we found increased sensitivity to and reliance on positive feedback in mAMPH-pretreated animals, with the mAMPHsingle group showing more pronounced use of this type of feedback. In contrast, overall negative feedback sensitivity was not altered following any mAMPH treatment. In addition to validating the enduring effects of mAMPH on early reversal learning, we found more consecutive error commissions before the first correct response in mAMPH-pretreated rats. This behavioral rigidity was negatively correlated with subregional frontocortical SERT whereas positive feedback sensitivity negatively correlated with striatal DAT binding. These results provide new evidence for the overlapping, yet dissociable roles of DA and 5HT systems in overcoming perseveration and in learning new reward rules. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Factors associated with vaginal birth after previous cesarean section in Brazilian women Factores relacionados con el parto vaginal en mujeres brasileñas con cesárea anterior

    Directory of Open Access Journals (Sweden)

    José Guilherme Cecatti

    2005-08-01

    Full Text Available OBJECTIVE: To identify factors associated with a vaginal second delivery in women who had one previous cesarean section. METHODS: A nested case-control study was carried out as a secondary data analysis of an original retrospective, population-based cohort study of women who delivered their first child during 1985 in the city of Campinas, São Paulo, Brazil, and who were interviewed 10 years later in 1995. The study population consisted of 1 352 women who had their first delivery by cesarean section and who had also had at least one subsequent delivery. The group of cases (150 women, around 11% of the sample consisted of women who had a vaginal second delivery, and the control group was made up of 1 202 women who had a cesarean section at second delivery. For each possible associated factor we calculated the odds ratio and 95% confidence interval. For ordered categorical variables the c² test for trend was used. Unconditional multivariate regression analysis was used to estimate the adjusted odds ratio for each associated factor. RESULTS: The factors significantly associated with vaginal delivery were monthly family income below 5-fold the Brazilian minimum monthly wage, reliance on the Brazilian national health system for healthcare, low maternal age, and first cesarean section indicated because of fetal breech or transverse presentation, or twin pregnancy. Among those women who also had a cesarean section at their second delivery, only 11% had undergone a trial of labor. CONCLUSIONS: The main determining factors for a vaginal second delivery in women with a previous cesarean section were unfavorable social and economic factors.OBJETIVO: Determinar qué factores se asocian con el parto vaginal en mujeres que han tenido una cesárea. MÉTODOS: Un estudio anidado de casos y testigos se llevó a cabo en forma de un análisis de datos secundarios procedentes de un estudio de cohorte -original, retrospectivo y de carácter poblacional- en mujeres

  10. Characteristics of health care organizations associated with learning and development: lessons from a pilot study.

    Science.gov (United States)

    Nyström, Monica

    2009-01-01

    Characteristics of health care organizations associated with an ability to learn from experiences and to develop and manage change were explored in this study. Understanding of these characteristics is necessary to identify factors influencing success in learning from the past and achieving future health care quality objectives. A literature review of the quality improvement, strategic organizational development and change management, organizational learning, and microsystems fields identified 20 organizational characteristics, grouped under (a) organizational systems, (b) key actors, and (c) change management processes. Qualitative methods, using interviews, focus group reports, and archival records, were applied to find associations between identified characteristics and 6 Swedish health care units externally evaluated as delivering high-quality care. Strong support for a characteristic was defined as units having more than 4 sources describing the characteristic as an important success factor. Eighteen characteristics had strong support from at least 2 units. The strongest evidence was found for the following: (i) key actors have long-term commitment, provide support, and make sense of ambiguous situations; (ii) organizational systems encourage employee commitment, participation, and involvement; and (iii) change management processes are employed systematically. Based on the results, a new model of "characteristics associated with learning and development in health care organizations" is proposed.

  11. Dissociating Crossmodal and Verbal Demands in Paired Associate Learning (PAL): What Drives the PAL-Reading Relationship?

    Science.gov (United States)

    Litt, Robin A.; de Jong, Peter F.; van Bergen, Elsje; Nation, Kate

    2013-01-01

    Recent research suggests that visual-verbal paired associate learning (PAL) may tap a crossmodal associative learning mechanism that plays a distinct role in reading development. However, evidence from children with dyslexia indicates that deficits in visual-verbal PAL are strongly linked to the verbal demands of the task. The primary aim of this…

  12. Hyper-Binding across Time: Age Differences in the Effect of Temporal Proximity on Paired-Associate Learning

    Science.gov (United States)

    Campbell, Karen L.; Trelle, Alexandra; Hasher, Lynn

    2014-01-01

    Older adults show hyper- (or excessive) binding effects for simultaneously and sequentially presented distraction. Here, we addressed the potential role of hyper-binding in paired-associate learning. Older and younger adults learned a list of word pairs and then received an associative recognition task in which rearranged pairs were formed from…

  13. Framework and catalogue of tools for Participatory monitoring for Farmer Family Learning Groups and Marketing Associations

    DEFF Research Database (Denmark)

    Vaarst, Mette; Nalunga, Jane; Tibasiima, Thaddeo

    2016-01-01

    external facilitators of FFLGs, four FFLG officers from the four organisations in ECOSAF, 21 Marketing Association officers, and staff members and volunteers from NOGAMU, SATNET and Organic Denmark. In the process we have worked together from each our context, and exchanged ideas on farmer group...... of this project (2013-2015) was Farmer Family Learning Groups (FFLG) as a method for developing long-term food security through social capital building. Furthermore, another project based on the FFLG approach but focusing on the formation of Marketing Associations (MAs) contributed to this booklet. This project...... development, participation and monitoring. Participatory monitoring in Farmer Family Learning Groups and Marketing Associations is for the people and the groups who have set goals for themselves and need to monitor themselves whether they are getting closer to the goals which they have set. These groups...

  14. Medical Student Perceptions of the Learning Environment: Learning Communities Are Associated With a More Positive Learning Environment in a Multi-Institutional Medical School Study.

    Science.gov (United States)

    Smith, Sunny D; Dunham, Lisette; Dekhtyar, Michael; Dinh, An; Lanken, Paul N; Moynahan, Kevin F; Stuber, Margaret L; Skochelak, Susan E

    2016-09-01

    Many medical schools have implemented learning communities (LCs) to improve the learning environment (LE) for students. The authors conducted this study to determine whether a relationship exists between medical student perceptions of the LE and presence of LCs during the preclerkship years. Students from 24 schools participating in the American Medical Association Learning Environment Study completed the 17-item Medical Student Learning Environment Survey (MSLES) at the end of their first and second years of medical school between 2011 and 2013. Mean total MSLES scores and individual item scores at the end of the first and second years in schools with and without LCs were compared with t tests, and effect sizes were calculated. Mixed-effects longitudinal models were used to control for student demographics and random school and student effects on the relationship between LC status and MSLES score. A total of 4,980 students (81% of 6,148 matriculants) from 18 schools with LCs and 6 without LCs participated. Mean [SD] MSLES scores were significantly higher in LC schools compared with non-LC schools at the end of year one (3.72 [0.44] versus 3.57 [0.43], P < .001) and year two (3.69 [0.49] versus 3.42 [0.54], P < .001). The effect size increased from 0.35 (small) at the end of year one to 0.53 (medium) at the end of year two. This large multi-institutional cohort study found that LCs at medical schools were associated with more positive perceptions of the LE by preclerkship students.

  15. Larger error signals in major depression are associated with better avoidance learning

    Directory of Open Access Journals (Sweden)

    James F eCavanagh

    2011-11-01

    Full Text Available The medial prefrontal cortex (mPFC is particularly reactive to signals of error, punishment, and conflict in the service of behavioral adaptation and it is consistently implicated in the etiology of Major Depressive Disorder (MDD. This association makes conceptual sense, given that MDD has been associated with hyper-reactivity in neural systems associated with punishment processing. Yet in practice, depression-related variance in measures of mPFC functioning often fails to relate to performance. For example, neuroelectric reflections of mediofrontal error signals are often found to be larger in MDD, but a deficit in post-error performance suggests that these error signals are not being used to rapidly adapt behavior. Thus, it remains unknown if depression-related variance in error signals reflects a meaningful alteration in the use of error or punishment information. However, larger mediofrontal error signals have also been related to another behavioral tendency: increased accuracy in avoidance learning. The integrity of this error-avoidance system remains untested in MDD. In this study, EEG was recorded as 21 symptomatic, drug-free participants with current or past MDD and 24 control participants performed a probabilistic reinforcement learning task. Depressed participants had larger mPFC EEG responses to error feedback than controls. The direct relationship between error signal amplitudes and avoidance learning accuracy was replicated. Crucially, this relationship was stronger in depressed participants for high conflict lose-lose situations, demonstrating a selective alteration of avoidance learning. This investigation provided evidence that larger error signal amplitudes in depression are associated with increased avoidance learning, identifying a candidate mechanistic model for hypersensitivity to negative outcomes in depression.

  16. Selectivity in associative learning: A cognitive stage framework for blocking and cue competition phenomena

    Directory of Open Access Journals (Sweden)

    Yannick eBoddez

    2014-11-01

    Full Text Available Blocking is the most important phenomenon in the history of associative learning theory: For over 40 years, blocking has inspired a whole generation of learning models. Blocking is part of a family of effects that are typically termed cue competition effects. Common amongst all cue competition effects is that a cue-outcome relation is poorly learned or poorly expressed because the cue is trained in the presence of an alternative predictor or cause of the outcome. We provide an overview of the cognitive processes involved in cue competition effects in humans and propose a stage framework that brings these processes together. The framework contends that the behavioral display of cue competition is cognitively construed following three stages that include (1 an encoding stage, (2 a retention stage, and (3 a performance stage. We argue that the stage framework supports a comprehensive understanding of cue competition effects.

  17. The real-time learning mechanism of the Scientific Research Associates Advanced Robotic System (SRAARS)

    Science.gov (United States)

    Chen, Alexander Y.

    1990-01-01

    Scientific research associates advanced robotic system (SRAARS) is an intelligent robotic system which has autonomous learning capability in geometric reasoning. The system is equipped with one global intelligence center (GIC) and eight local intelligence centers (LICs). It controls mainly sixteen links with fourteen active joints, which constitute two articulated arms, an extensible lower body, a vision system with two CCD cameras and a mobile base. The on-board knowledge-based system supports the learning controller with model representations of both the robot and the working environment. By consecutive verifying and planning procedures, hypothesis-and-test routines and learning-by-analogy paradigm, the system would autonomously build up its own understanding of the relationship between itself (i.e., the robot) and the focused environment for the purposes of collision avoidance, motion analysis and object manipulation. The intelligence of SRAARS presents a valuable technical advantage to implement robotic systems for space exploration and space station operations.

  18. Associations and propositions: the case for a dual-process account of learning in humans.

    Science.gov (United States)

    McLaren, I P L; Forrest, C L D; McLaren, R P; Jones, F W; Aitken, M R F; Mackintosh, N J

    2014-02-01

    We review evidence that supports the conclusion that people can and do learn in two distinct ways - one associative, the other propositional. No one disputes that we solve problems by testing hypotheses and inducing underlying rules, so the issue amounts to deciding whether there is evidence that we (and other animals) also rely on a simpler, associative system, that detects the frequency of occurrence of different events in our environment and the contingencies between them. There is neuroscientific evidence that associative learning occurs in at least some animals (e.g., Aplysia californica), so it must be the case that associative learning has evolved. Since both associative and propositional theories can in principle account for many instances of successful learning, the problem is then to show that there are at least some cases where the two classes of theory predict different outcomes. We offer a demonstration of cue competition effects in humans under incidental conditions as evidence against the argument that all such effects are based on cognitive inference. The latter supposition would imply that if the necessary information is unavailable to inference then no cue competition should occur. We then discuss the case of unblocking by reinforcer omission, where associative theory predicts an irrational solution to the problem, and consider the phenomenon of the Perruchet effect, in which conscious expectancy and conditioned response dissociate. Further discussion makes use of evidence that people will sometimes provide one solution to a problem when it is presented to them in summary form, and another when they are presented in rapid succession with trial-by trial information. We also demonstrate that people trained on a discrimination may show a peak shift (predicted by associative theory), but given the time and opportunity to detect the relationships between S+ and S-, show rule-based behavior instead. Finally, we conclude by presenting evidence that

  19. Precise-Spike-Driven Synaptic Plasticity: Learning Hetero-Association of Spatiotemporal Spike Patterns

    Science.gov (United States)

    Yu, Qiang; Tang, Huajin; Tan, Kay Chen; Li, Haizhou

    2013-01-01

    A new learning rule (Precise-Spike-Driven (PSD) Synaptic Plasticity) is proposed for processing and memorizing spatiotemporal patterns. PSD is a supervised learning rule that is analytically derived from the traditional Widrow-Hoff rule and can be used to train neurons to associate an input spatiotemporal spike pattern with a desired spike train. Synaptic adaptation is driven by the error between the desired and the actual output spikes, with positive errors causing long-term potentiation and negative errors causing long-term depression. The amount of modification is proportional to an eligibility trace that is triggered by afferent spikes. The PSD rule is both computationally efficient and biologically plausible. The properties of this learning rule are investigated extensively through experimental simulations, including its learning performance, its generality to different neuron models, its robustness against noisy conditions, its memory capacity, and the effects of its learning parameters. Experimental results show that the PSD rule is capable of spatiotemporal pattern classification, and can even outperform a well studied benchmark algorithm with the proposed relative confidence criterion. The PSD rule is further validated on a practical example of an optical character recognition problem. The results again show that it can achieve a good recognition performance with a proper encoding. Finally, a detailed discussion is provided about the PSD rule and several related algorithms including tempotron, SPAN, Chronotron and ReSuMe. PMID:24223789

  20. Distinct patterns of functional and structural neuroplasticity associated with learning Morse code.

    Science.gov (United States)

    Schmidt-Wilcke, T; Rosengarth, K; Luerding, R; Bogdahn, U; Greenlee, M W

    2010-07-01

    Learning is based on neuroplasticity, i.e. on the capability of the brain to adapt to new experiences. Different mechanisms of neuroplasticity have been described, ranging from synaptic remodeling to changes in complex neural circuitry. To further study the relationship between changes in neural activity and changes in gray matter density associated with learning, we performed a combined longitudinal functional and morphometric magnetic resonance imaging (MRI) study on healthy volunteers who learned to decipher Morse code. We investigated 16 healthy subjects using functional MR imaging (fMRI) and voxel-based morphometry (VBM) before and after they had learned to decipher Morse code. The same set of Morse-code signals was presented to participants pre- and post-training. We found an increase in task-specific neural activity in brain regions known to be critically involved in language perception and memory, such as the inferior parietal cortex bilaterally and the medial parietal cortex during Morse code deciphering. Furthermore we found an increase in gray matter density in the left occipitotemporal region, extending into the fusiform gyrus. Anatomically neighboring sites of functional and structural neuroplasticity were revealed in the left occipitotemporal/inferior temporal cortex, but these regions only marginally overlapped. Implications of this morpho-functional dissociation for learning concepts are discussed. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  1. Precise-spike-driven synaptic plasticity: learning hetero-association of spatiotemporal spike patterns.

    Directory of Open Access Journals (Sweden)

    Qiang Yu

    Full Text Available A new learning rule (Precise-Spike-Driven (PSD Synaptic Plasticity is proposed for processing and memorizing spatiotemporal patterns. PSD is a supervised learning rule that is analytically derived from the traditional Widrow-Hoff rule and can be used to train neurons to associate an input spatiotemporal spike pattern with a desired spike train. Synaptic adaptation is driven by the error between the desired and the actual output spikes, with positive errors causing long-term potentiation and negative errors causing long-term depression. The amount of modification is proportional to an eligibility trace that is triggered by afferent spikes. The PSD rule is both computationally efficient and biologically plausible. The properties of this learning rule are investigated extensively through experimental simulations, including its learning performance, its generality to different neuron models, its robustness against noisy conditions, its memory capacity, and the effects of its learning parameters. Experimental results show that the PSD rule is capable of spatiotemporal pattern classification, and can even outperform a well studied benchmark algorithm with the proposed relative confidence criterion. The PSD rule is further validated on a practical example of an optical character recognition problem. The results again show that it can achieve a good recognition performance with a proper encoding. Finally, a detailed discussion is provided about the PSD rule and several related algorithms including tempotron, SPAN, Chronotron and ReSuMe.

  2. Span: spike pattern association neuron for learning spatio-temporal spike patterns.

    Science.gov (United States)

    Mohemmed, Ammar; Schliebs, Stefan; Matsuda, Satoshi; Kasabov, Nikola

    2012-08-01

    Spiking Neural Networks (SNN) were shown to be suitable tools for the processing of spatio-temporal information. However, due to their inherent complexity, the formulation of efficient supervised learning algorithms for SNN is difficult and remains an important problem in the research area. This article presents SPAN - a spiking neuron that is able to learn associations of arbitrary spike trains in a supervised fashion allowing the processing of spatio-temporal information encoded in the precise timing of spikes. The idea of the proposed algorithm is to transform spike trains during the learning phase into analog signals so that common mathematical operations can be performed on them. Using this conversion, it is possible to apply the well-known Widrow-Hoff rule directly to the transformed spike trains in order to adjust the synaptic weights and to achieve a desired input/output spike behavior of the neuron. In the presented experimental analysis, the proposed learning algorithm is evaluated regarding its learning capabilities, its memory capacity, its robustness to noisy stimuli and its classification performance. Differences and similarities of SPAN regarding two related algorithms, ReSuMe and Chronotron, are discussed.

  3. Precise-spike-driven synaptic plasticity: learning hetero-association of spatiotemporal spike patterns.

    Science.gov (United States)

    Yu, Qiang; Tang, Huajin; Tan, Kay Chen; Li, Haizhou

    2013-01-01

    A new learning rule (Precise-Spike-Driven (PSD) Synaptic Plasticity) is proposed for processing and memorizing spatiotemporal patterns. PSD is a supervised learning rule that is analytically derived from the traditional Widrow-Hoff rule and can be used to train neurons to associate an input spatiotemporal spike pattern with a desired spike train. Synaptic adaptation is driven by the error between the desired and the actual output spikes, with positive errors causing long-term potentiation and negative errors causing long-term depression. The amount of modification is proportional to an eligibility trace that is triggered by afferent spikes. The PSD rule is both computationally efficient and biologically plausible. The properties of this learning rule are investigated extensively through experimental simulations, including its learning performance, its generality to different neuron models, its robustness against noisy conditions, its memory capacity, and the effects of its learning parameters. Experimental results show that the PSD rule is capable of spatiotemporal pattern classification, and can even outperform a well studied benchmark algorithm with the proposed relative confidence criterion. The PSD rule is further validated on a practical example of an optical character recognition problem. The results again show that it can achieve a good recognition performance with a proper encoding. Finally, a detailed discussion is provided about the PSD rule and several related algorithms including tempotron, SPAN, Chronotron and ReSuMe.

  4. Factores socioacadémicos, estilo de aprendizaje, nivel intelectual y su relación con el rendimiento académico previo de médicos internos de pregrado Socioacademic factors, style of learning, intellectual level and their relationship with the previous academic yield of medical students

    Directory of Open Access Journals (Sweden)

    J.L. Padierna-Luna

    2009-06-01

    descriptive statistic and multiple regression to look for associations between the variables. Results and conclusions. The feminine sex with the 59.2% predominated (n = 103 on the masculine one, 40.8% (n = 71. The average of age was of 23.63 years with a rank from 21 to 33. There were no significant differences of gender in the previous yield ((8.21 vs 8.25. The relation between the socioacademic factors, styles of learning and intellectual level with the academic yield was evaluated, with an interval of confidence of 95%. Of the socioacademic factor, only the age is related inversely to the yield, with r = 0.2 and p < 0.001. The SL does not bear any relation to the yield. IL it is related significantly to the yield (p < 0.001.

  5. Disruption of paired-associate learning in rat offspring perinatally exposed to dioxins.

    Science.gov (United States)

    Kakeyama, Masaki; Endo, Toshihiro; Zhang, Yan; Miyazaki, Wataru; Tohyama, Chiharu

    2014-03-01

    The prevalence of cognitive abnormalities in children has partly been ascribed to environmental chemical exposure. Appropriate animal models and tools for evaluating higher brain function are required to examine this problem. A recently developed behavioral test in which rats learn six unique flavor-location pairs in a test arena was used to evaluate paired-associate learning, a hallmark of the higher cognitive function that is essential to language learning in humans. Pregnant Long-Evans rats were dosed by gavage with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or 2,3,7,8-tetrabromodibenzo-p-dioxin (TBDD) at a dose of 0, 200, or 800 ng/kg (referred as Control, TCDD-200, TCDD-800, TBDD-200, or TBDD-800, hereafter) on gestational day 15, and the offspring was tested during adulthood. Paired-associate learning was found to be impaired in the TCDD-200 and TBDD-200 groups, but not in either group exposed to 800 ng/kg, the observations of which were ensured by non-cued trials. As for the emotional aspect, during habituation, the TCDD-200 and TBDD-200 groups showed significantly longer latencies to enter the test arena from a start box than the Control, TCDD-800, and TBDD-800 groups, suggesting that the TCDD-200 and TBDD-200 groups manifested anxiety-like behavior. Thus, both the chlorinated dioxin and its brominated congener affected higher brain function to a similar extent in a nearly identical manner. Use of the behavioral test that can evaluate paired-associate learning in rats demonstrated that in utero and lactational exposure to not only TCDD but also TBDD perturbed higher brain function in rat offspring in a nonmonotonic manner.

  6. Event timing in associative learning: from biochemical reaction dynamics to behavioural observations.

    Directory of Open Access Journals (Sweden)

    Ayse Yarali

    Full Text Available Associative learning relies on event timing. Fruit flies for example, once trained with an odour that precedes electric shock, subsequently avoid this odour (punishment learning; if, on the other hand the odour follows the shock during training, it is approached later on (relief learning. During training, an odour-induced Ca(++ signal and a shock-induced dopaminergic signal converge in the Kenyon cells, synergistically activating a Ca(++-calmodulin-sensitive adenylate cyclase, which likely leads to the synaptic plasticity underlying the conditioned avoidance of the odour. In Aplysia, the effect of serotonin on the corresponding adenylate cyclase is bi-directionally modulated by Ca(++, depending on the relative timing of the two inputs. Using a computational approach, we quantitatively explore this biochemical property of the adenylate cyclase and show that it can generate the effect of event timing on associative learning. We overcome the shortage of behavioural data in Aplysia and biochemical data in Drosophila by combining findings from both systems.

  7. Comparing elemental and configural associative theories in human causal learning: a case for attention.

    Science.gov (United States)

    Lachnit, Harald; Schultheis, Holger; König, Stephan; Ungör, Metin; Melchers, Klaus

    2008-04-01

    In two causal learning experiments with human participants, the authors compared various associative theories that assumed either elemental (unique cue, modified unique cue, replaced elements model, and Harris' model) or configural processing of stimuli (Pearce's theory and a modification of it). The authors used modified patterning problems initially suggested by Redhead and Pearce (1995). Predictions for all theories were generated by computer simulations. Both configural theories and the unique cue approach failed to account for the observations. The replaced elements model was able to account for part of the data, but only if the replacement parameters could vary across discrimination problems. The Harris model and the modified unique cue approach, assuming that the salience of stimuli decreases with an increasing number of stimuli in a compound, successfully accounted for all of our data. This success implies that attentional factors should be explicitly taken into account in associative learning theory.

  8. Networks of Learning : Professional Association and the Continuing Education of Teachers of Mathematics in Pakistan

    DEFF Research Database (Denmark)

    Baber, Sikunder Ali

    Importance of the professional development of teachers has been recognized and research has contributed greatly in terms of proposing variety of approaches for the development of teachers,both pre-service and in-service. Among them, networking among teachers, teacher educators,curriculum developers...... and policy makers have been recently receiving attention an innovative and flexible professional development forum for creating ownership among these stakeholders' regarding implementing change and reforms in educational landscape in different countries. The paper draws on the notion of "networking......" and shows how a number of professional associations have become as networks of learning to encourage the continuing professional education of both pre-service and in-service teachers in the context of Pakistan. A case of the Mathematics Association of Pakistan (MAP) as a Network of Learning is presented...

  9. Fusing Data Mining, Machine Learning and Traditional Statistics to Detect Biomarkers Associated with Depression.

    Directory of Open Access Journals (Sweden)

    Joanna F Dipnall

    Full Text Available Atheoretical large-scale data mining techniques using machine learning algorithms have promise in the analysis of large epidemiological datasets. This study illustrates the use of a hybrid methodology for variable selection that took account of missing data and complex survey design to identify key biomarkers associated with depression from a large epidemiological study.The study used a three-step methodology amalgamating multiple imputation, a machine learning boosted regression algorithm and logistic regression, to identify key biomarkers associated with depression in the National Health and Nutrition Examination Study (2009-2010. Depression was measured using the Patient Health Questionnaire-9 and 67 biomarkers were analysed. Covariates in this study included gender, age, race, smoking, food security, Poverty Income Ratio, Body Mass Index, physical activity, alcohol use, medical conditions and medications. The final imputed weighted multiple logistic regression model included possible confounders and moderators.After the creation of 20 imputation data sets from multiple chained regression sequences, machine learning boosted regression initially identified 21 biomarkers associated with depression. Using traditional logistic regression methods, including controlling for possible confounders and moderators, a final set of three biomarkers were selected. The final three biomarkers from the novel hybrid variable selection methodology were red cell distribution width (OR 1.15; 95% CI 1.01, 1.30, serum glucose (OR 1.01; 95% CI 1.00, 1.01 and total bilirubin (OR 0.12; 95% CI 0.05, 0.28. Significant interactions were found between total bilirubin with Mexican American/Hispanic group (p = 0.016, and current smokers (p<0.001.The systematic use of a hybrid methodology for variable selection, fusing data mining techniques using a machine learning algorithm with traditional statistical modelling, accounted for missing data and complex survey sampling

  10. The speed of learning instructed stimulus-response association rules in human: experimental data and model.

    Science.gov (United States)

    Bugmann, Guido; Goslin, Jeremy; Duchamp-Viret, Patricia

    2013-11-06

    Humans can learn associations between visual stimuli and motor responses from just a single instruction. This is known to be a fast process, but how fast is it? To answer this question, we asked participants to learn a briefly presented (200ms) stimulus-response rule, which they then had to rapidly apply after a variable delay of between 50 and 1300ms. Participants showed a longer response time with increased variability for short delays. The error rate was low and did not vary with the delay, showing that participants were able to encode the rule correctly in less than 250ms. This time is close to the fastest synaptic learning speed deemed possible by diffusive influx of AMPA receptors. Learning continued at a slower pace in the delay period and was fully completed in average 900ms after rule presentation onset, when response latencies dropped to levels consistent with basic reaction times. A neural model was proposed that explains the reduction of response times and of their variability with the delay by (i) a random synaptic learning process that generates weights of average values increasing with the learning time, followed by (ii) random crossing of the firing threshold by a leaky integrate-and-fire neuron model, and (iii) assuming that the behavioural response is initiated when all neurons in a pool of m neurons have fired their first spike after input onset. Values of m=2 or 3 were consistent with the experimental data. The proposed model is the simplest solution consistent with neurophysiological knowledge. Additional experiments are suggested to test the hypothesis underlying the model and also to explore forgetting effects for which there were indications for the longer delay conditions. This article is part of a Special Issue entitled Neural Coding 2012. © 2013 Elsevier B.V. All rights reserved.

  11. Associative learning as higher order cognition: Learning in human and nonhuman animals from the perspective of propositional theories and relational frame theory.

    Science.gov (United States)

    De Houwer, Jan; Hughes, Sean; Barnes-Holmes, Dermot

    2016-08-01

    We aim to provide a new perspective on the old debate about whether evidence for higher order cognition in nonhuman animals can be reinterpreted in terms of associative learning. Our starting point is the idea that associative learning is best thought of as an effect (i.e., the impact of paired events on behavior) rather than a specific mental process (e.g., the formation of associations). This idea allows us to consider (a) propositional theories according to which associative learning is mediated by higher order mental processes akin to problem solving and (b) relational frame theory that allows one to think of seemingly simple associative learning effects as instances of a complex phenomenon known as arbitrarily applicable relational responding. Based on these 2 theories, we argue that (a) higher order cognition and associative learning are not necessarily mutually exclusive and (b) a more sophisticated conceptualization of higher order cognition is warranted. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  12. Appetitive Olfactory Learning and Long-Term Associative Memory in Caenorhabditis elegans

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    Ichiro N. Maruyama

    2017-05-01

    Full Text Available Because of the relative simplicity of its nervous system, Caenorhabditis elegans is a useful model organism to study learning and memory at cellular and molecular levels. For appetitive conditioning in C. elegans, food has exclusively been used as an unconditioned stimulus (US. It may be difficult to analyze neuronal circuits for associative memory since food is a multimodal combination of olfactory, gustatory, and mechanical stimuli. Here, we report classical appetitive conditioning and associative memory in C. elegans, using 1-nonanol as a conditioned stimulus (CS, and potassium chloride (KCl as a US. Before conditioning, C. elegans innately avoided 1-nonanol, an aversive olfactory stimulus, and was attracted by KCl, an appetitive gustatory stimulus, on assay agar plates. Both massed training without an intertrial interval (ITI and spaced training with a 10-min ITI induced significant levels of memory of association regarding the two chemicals. Memory induced by massed training decayed within 6 h, while that induced by spaced training was retained for more than 6 h. Animals treated with inhibitors of transcription or translation formed the memory induced by spaced training less efficiently than untreated animals, whereas the memory induced by massed training was not significantly affected by such treatments. By definition, therefore, memories induced by massed training and spaced training are classified as short-term memory (STM and long-term memory (LTM, respectively. When animals conditioned by spaced training were exposed to 1-nonanol alone, their learning index was lower than that of untreated animals, suggesting that extinction learning occurs in C. elegans. In support of these results, C. elegans mutants defective in nmr-1, encoding an NMDA receptor subunit, formed both STM and LTM less efficiently than wild-type animals, while mutations in crh-1, encoding a ubiquitous transcription factor CREB required for memory consolidation, affected

  13. Presynaptic GABAB Receptors Regulate Hippocampal Synapses during Associative Learning in Behaving Mice.

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    M Teresa Jurado-Parras

    Full Text Available GABAB receptors are the G-protein-coupled receptors for GABA, the main inhibitory neurotransmitter in the central nervous system. Pharmacological activation of GABAB receptors regulates neurotransmission and neuronal excitability at pre- and postsynaptic sites. Electrophysiological activation of GABAB receptors in brain slices generally requires strong stimulus intensities. This raises the question as to whether behavioral stimuli are strong enough to activate GABAB receptors. Here we show that GABAB1a-/- mice, which constitutively lack presynaptic GABAB receptors at glutamatergic synapses, are impaired in their ability to acquire an operant learning task. In vivo recordings during the operant conditioning reveal a deficit in learning-dependent increases in synaptic strength at CA3-CA1 synapses. Moreover, GABAB1a-/- mice fail to synchronize neuronal activity in the CA1 area during the acquisition process. Our results support that activation of presynaptic hippocampal GABAB receptors is important for acquisition of a learning task and for learning-associated synaptic changes and network dynamics.

  14. Evolution of social learning when high expected payoffs are associated with high risk of failure

    Science.gov (United States)

    Arbilly, Michal; Motro, Uzi; Feldman, Marcus W.; Lotem, Arnon

    2011-01-01

    In an environment where the availability of resources sought by a forager varies greatly, individual foraging is likely to be associated with a high risk of failure. Foragers that learn where the best sources of food are located are likely to develop risk aversion, causing them to avoid the patches that are in fact the best; the result is sub-optimal behaviour. Yet, foragers living in a group may not only learn by themselves, but also by observing others. Using evolutionary agent-based computer simulations of a social foraging game, we show that in an environment where the most productive resources occur with the lowest probability, socially acquired information is strongly favoured over individual experience. While social learning is usually regarded as beneficial because it filters out maladaptive behaviours, the advantage of social learning in a risky environment stems from the fact that it allows risk aversion to be circumvented and the best food source to be revisited despite repeated failures. Our results demonstrate that the consequences of individual risk aversion may be better understood within a social context and suggest one possible explanation for the strong preference for social information over individual experience often observed in both humans and animals. PMID:21508013

  15. Individual differences in task-specific paired associates learning in older adults: the role of processing speed and working memory.

    Science.gov (United States)

    Kurtz, Tanja; Mogle, Jacqueline; Sliwinski, Martin J; Hofer, Scott M

    2013-01-01

    BACKGROUND/STUDY CONTEXT: The role of processing speed and working memory was investigated in terms of individual differences in task-specific paired associates learning in a sample of older adults. Task-specific learning, as distinct from content-oriented item-specific learning, refers to gains in performance due to repeated practice on a learning task in which the to-be-learned material changes over trials. Learning trajectories were modeled within an intensive repeated-measures design based on participants obtained from an opt-in Internet-based sampling service (M(age) = 65.3, SD = 4.81). Participants completed an eight-item paired associates task daily over a 7-day period. Results indicated that a three-parameter hyperbolic model (i.e., initial level, learning rate, and asymptotic performance) best described learning trajectory. After controlling for age-related effects, both higher working memory and higher processing speed had a positive effect on all three learning parameters. These results emphasize the role of cognitive abilities for individual differences in task-specific learning of older adults.

  16. Can convict Cichlids (Amatitlania siquia socially learn the degree of predation risk associated with novel visual cues in their environment?

    Directory of Open Access Journals (Sweden)

    Patrick M Barks

    Full Text Available For many animals, the ability to distinguish cues indicative of predation risk from cues unrelated to predation risk is not entirely innate, but rather is learned and improved with experience. Two pathways to such learning are possible. First, an animal could initially express antipredator behaviour toward a wide range of cues and subsequently learn which of those cues are non-threatening. Alternatively, it could initially express no antipredator behaviour toward a wide range of cues and subsequently learn which of them are threatening. While the learned recognition of threatening cues may occur either through personal interaction with a cue (asocial learning or through observation of the behaviour of social companions toward a cue (social learning, the learned recognition of non-threatening cues seems to occur exclusively through habituation, a form of asocial learning. Here, we tested whether convict cichlid fish (Amatitlaniasiquia can socially learn to recognize visual cues in their environment as either threatening or non-threatening. We exposed juvenile convict cichlids simultaneously to a novel visual cue and one of three (visual social cues: a social cue indicative of non-risk (the sight of conspecifics that had previously been habituated to the novel cue, a social cue indicative of predation risk (the sight of conspecifics trained to fear the novel cue, or a control treatment with no social cue. The subsequent response of focal fish, when presented with the novel cue alone, was not influenced by the social cue that they had previously witnessed. We therefore did not find evidence that convict cichlids in our study could use social learning to recognize novel visual cues as either threatening or non-threatening. We consider alternative explanations for our findings.

  17. ALOUD biological: Adult Learning Open University Determinants study - Association of biological determinants with study success in formal lifelong learners

    NARCIS (Netherlands)

    Gijselaers, Jérôme; De Groot, Renate; Kirschner, Paul A.

    2012-01-01

    Gijselaers, H. J. M., De Groot, R. H. M., & Kirschner, P. A. (2012, 15 March). ALOUD biological: Adult Learning Open University Determinants study - Association of biological determinants with study success in formal lifelong learners. Presentation given at the plenary meeting of Learning &

  18. Beliefs Associated with Support for Child-Centred Learning Environment among Hong Kong Pre-Service Early Childhood Teachers

    Science.gov (United States)

    Cheung, Sum Kwing; Ling, Elsa Ka-wei; Leung, Suzannie Kit Ying

    2017-01-01

    The physical, social and temporal dimensions of the classroom environment have an important role in children's learning. This study examines the level of support for child-centred learning, and its associated beliefs, that is provided by Hong Kong's pre-service early childhood teachers. Two hundred and seventy-five students from a pre-service…

  19. Learning-Dependent Changes of Associations between Unfamiliar Words and Perceptual Features: A 15-Day Longitudinal Study

    Science.gov (United States)

    Kambara, Toshimune; Tsukiura, Takashi; Shigemune, Yayoi; Kanno, Akitake; Nouchi, Rui; Yomogida, Yukihito; Kawashima, Ryuta

    2013-01-01

    This study examined behavioral changes in 15-day learning of word-picture (WP) and word-sound (WS) associations, using meaningless stimuli. Subjects performed a learning task and two recognition tasks under the WP and WS conditions every day for 15 days. Two main findings emerged from this study. First, behavioral data of recognition accuracy and…

  20. Dreaming of a learning task is associated with enhanced sleep-dependent memory consolidation.

    Science.gov (United States)

    Wamsley, Erin J; Tucker, Matthew; Payne, Jessica D; Benavides, Joseph A; Stickgold, Robert

    2010-05-11

    It is now well established that postlearning sleep is beneficial for human memory performance. Meanwhile, human and animal studies have demonstrated that learning-related neural activity is re-expressed during posttraining nonrapid eye movement (NREM) sleep. NREM sleep processes appear to be particularly beneficial for hippocampus-dependent forms of memory. These observations suggest that learning triggers the reactivation and reorganization of memory traces during sleep, a systems-level process that in turn enhances behavioral performance. Here, we hypothesized that dreaming about a learning experience during NREM sleep would be associated with improved performance on a hippocampus-dependent spatial memory task. Subjects were trained on a virtual navigation task and then retested on the same task 5 hr after initial training. Improved performance at retest was strongly associated with task-related dream imagery during an intervening afternoon nap. Task-related thoughts during wakefulness, in contrast, did not predict improved performance. These observations suggest that sleep-dependent memory consolidation in humans is facilitated by the offline reactivation of recently formed memories, and furthermore that dream experiences reflect this memory processing. That similar effects were not observed during wakefulness suggests that these mnemonic processes are specific to the sleep state. (c) 2010 Elsevier Ltd. All rights reserved.

  1. Early exposure to volatile anesthetics impairs long-term associative learning and recognition memory.

    Science.gov (United States)

    Lee, Bradley H; Chan, John Thomas; Hazarika, Obhi; Vutskits, Laszlo; Sall, Jeffrey W

    2014-01-01

    Anesthetic exposure early in life affects neural development and long-term cognitive function, but our understanding of the types of memory that are altered is incomplete. Specific cognitive tests in rodents that isolate different memory processes provide a useful approach for gaining insight into this issue. Postnatal day 7 (P7) rats were exposed to either desflurane or isoflurane at 1 Minimum Alveolar Concentration for 4 h. Acute neuronal death was assessed 12 h later in the thalamus, CA1-3 regions of hippocampus, and dentate gyrus. In separate behavioral experiments, beginning at P48, subjects were evaluated in a series of object recognition tests relying on associative learning, as well as social recognition. Exposure to either anesthetic led to a significant increase in neuroapoptosis in each brain region. The extent of neuronal death did not differ between groups. Subjects were unaffected in simple tasks of novel object and object-location recognition. However, anesthetized animals from both groups were impaired in allocentric object-location memory and a more complex task requiring subjects to associate an object with its location and contextual setting. Isoflurane exposure led to additional impairment in object-context association and social memory. Isoflurane and desflurane exposure during development result in deficits in tasks relying on associative learning and recognition memory. Isoflurane may potentially cause worse impairment than desflurane.

  2. Early exposure to volatile anesthetics impairs long-term associative learning and recognition memory.

    Directory of Open Access Journals (Sweden)

    Bradley H Lee

    Full Text Available Anesthetic exposure early in life affects neural development and long-term cognitive function, but our understanding of the types of memory that are altered is incomplete. Specific cognitive tests in rodents that isolate different memory processes provide a useful approach for gaining insight into this issue.Postnatal day 7 (P7 rats were exposed to either desflurane or isoflurane at 1 Minimum Alveolar Concentration for 4 h. Acute neuronal death was assessed 12 h later in the thalamus, CA1-3 regions of hippocampus, and dentate gyrus. In separate behavioral experiments, beginning at P48, subjects were evaluated in a series of object recognition tests relying on associative learning, as well as social recognition.Exposure to either anesthetic led to a significant increase in neuroapoptosis in each brain region. The extent of neuronal death did not differ between groups. Subjects were unaffected in simple tasks of novel object and object-location recognition. However, anesthetized animals from both groups were impaired in allocentric object-location memory and a more complex task requiring subjects to associate an object with its location and contextual setting. Isoflurane exposure led to additional impairment in object-context association and social memory.Isoflurane and desflurane exposure during development result in deficits in tasks relying on associative learning and recognition memory. Isoflurane may potentially cause worse impairment than desflurane.

  3. Not so close but still extremely loud: recollection of the World Trade Center terror attack and previous hurricanes moderates the association between exposure to hurricane Sandy and posttraumatic stress symptoms.

    Science.gov (United States)

    Palgi, Yuval; Shrira, Amit; Hamama-Raz, Yaira; Palgi, Sharon; Goodwin, Robin; Ben-Ezra, Menachem

    2014-05-01

    The present study examined whether recollections of the World Trade Center (WTC) terror attack and previous hurricanes moderated the relationship between exposure to Hurricane Sandy and related posttraumatic stress disorder (PTSD) symptoms. An online sample of 1000 participants from affected areas completed self-report questionnaires a month after Hurricane Sandy hit the East Coast of the United States. Participants reported their exposure to Hurricane Sandy, their PTSD symptoms, and recollections of the WTC terror attack and previous hurricanes elicited due to Hurricane Sandy. Exposure to Hurricane Sandy was related to PTSD symptoms among those with high level of recollections of the WTC terror attack and past hurricanes, but not among those with low level of recollections. The aftermath of exposure to Hurricane Sandy is related not only to exposure, but also to its interaction with recollections of past traumas. These findings have theoretical and practical implications for practitioners and health policy makers in evaluating and interpreting the impact of past memories on future natural disasters. This may help in intervention plans of social and psychological services. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. The Transition to Minimal Consciousness through the Evolution of Associative Learning

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    Bronfman, Zohar Z.; Ginsburg, Simona; Jablonka, Eva

    2016-01-01

    The minimal state of consciousness is sentience. This includes any phenomenal sensory experience – exteroceptive, such as vision and olfaction; interoceptive, such as pain and hunger; or proprioceptive, such as the sense of bodily position and movement. We propose unlimited associative learning (UAL) as the marker of the evolutionary transition to minimal consciousness (or sentience), its phylogenetically earliest sustainable manifestation and the driver of its evolution. We define and describe UAL at the behavioral and functional level and argue that the structural-anatomical implementations of this mode of learning in different taxa entail subjective feelings (sentience). We end with a discussion of the implications of our proposal for the distribution of consciousness in the animal kingdom, suggesting testable predictions, and revisiting the ongoing debate about the function of minimal consciousness in light of our approach. PMID:28066282

  5. The Transition to Minimal Consciousness through the Evolution of Associative Learning.

    Science.gov (United States)

    Bronfman, Zohar Z; Ginsburg, Simona; Jablonka, Eva

    2016-01-01

    The minimal state of consciousness is sentience. This includes any phenomenal sensory experience - exteroceptive, such as vision and olfaction; interoceptive, such as pain and hunger; or proprioceptive, such as the sense of bodily position and movement. We propose unlimited associative learning (UAL) as the marker of the evolutionary transition to minimal consciousness (or sentience) , its phylogenetically earliest sustainable manifestation and the driver of its evolution. We define and describe UAL at the behavioral and functional level and argue that the structural-anatomical implementations of this mode of learning in different taxa entail subjective feelings (sentience). We end with a discussion of the implications of our proposal for the distribution of consciousness in the animal kingdom, suggesting testable predictions, and revisiting the ongoing debate about the function of minimal consciousness in light of our approach.

  6. Learning of arbitrary association between visual and auditory novel stimuli in adults: the "bond effect" of haptic exploration.

    Directory of Open Access Journals (Sweden)

    Benjamin Fredembach

    Full Text Available BACKGROUND: It is well-known that human beings are able to associate stimuli (novel or not perceived in their environment. For example, this ability is used by children in reading acquisition when arbitrary associations between visual and auditory stimuli must be learned. The studies tend to consider it as an "implicit" process triggered by the learning of letter/sound correspondences. The study described in this paper examined whether the addition of the visuo-haptic exploration would help adults to learn more effectively the arbitrary association between visual and auditory novel stimuli. METHODOLOGY/PRINCIPAL FINDINGS: Adults were asked to learn 15 new arbitrary associations between visual stimuli and their corresponding sounds using two learning methods which differed according to the perceptual modalities involved in the exploration of the visual stimuli. Adults used their visual modality in the "classic" learning method and both their visual and haptic modalities in the "multisensory" learning one. After both learning methods, participants showed a similar above-chance ability to recognize the visual and auditory stimuli and the audio-visual associations. However, the ability to recognize the visual-auditory associations was better after the multisensory method than after the classic one. CONCLUSION/SIGNIFICANCE: This study revealed that adults learned more efficiently the arbitrary association between visual and auditory novel stimuli when the visual stimuli were explored with both vision and touch. The results are discussed from the perspective of how they relate to the functional differences of the manual haptic modality and the hypothesis of a "haptic bond" between visual and auditory stimuli.

  7. The association between dopamine receptor (DRD4) gene polymorphisms and second language learning style and behavioral variability in undergraduate students in Turkey.

    Science.gov (United States)

    Maras Atabay, Meltem; Safi Oz, Zehra; Kurtman, Elvan

    2014-08-01

    The dopamine D4 receptor gene (DRD4) encodes a receptor for dopamine, a chemical messenger used in the brain. One variant of the DRD4 gene, the 7R allele, is believed to be associated with attention deficit hyperactivity disorder (ADHD). The aim of this study was to investigate the relationships between repeat polymorphisms in dopamine DRD4 and second language learning styles such as visual (seeing), tactile (touching), auditory (hearing), kinesthetic (moving) and group/individual learning styles, as well as the relationships among DRD4 gene polymorphisms and ADHD in undergraduate students. A total of 227 students between the ages of 17-21 years were evaluated using the Wender Utah rating scale and DSM-IV diagnostic criteria for ADHD. Additionally, Reid's perceptual learning style questionnaire for second language learning style was applied. In addition, these students were evaluated for social distress factors using the list of Threatening Events (TLE); having had no TLE, having had just one TLE or having had two or more TLEs within the previous 6 months before the interview. For DRD4 gene polymorphisms, DNA was extracted from whole blood using the standard phenol/chloroform method and genotyped using polymerase chain reaction. Second language learners with the DRD4.7+ repeats showed kinaesthetic and auditory learning styles, while students with DRD4.7-repeats showed visual, tactile and group learning, and also preferred the more visual learning styles [Formula: see text]. We also demonstrated that the DRD4 polymorphism significantly affected the risk effect conferred by an increasing level of exposure to TLE.

  8. Factors associated with pharmacy students' attitudes towards learning communication skills - A study among Nordic pharmacy students.

    Science.gov (United States)

    Svensberg, Karin; Brandlistuen, Ragnhild Eek; Björnsdottir, Ingunn; Sporrong, Sofia Kälvemark

    2018-03-01

    Good communication skills are essential for pharmacy students to help patients with their medicines. Students' attitudes towards communication skills learning will influence their willingness to engage in communication training, and their skills when dealing with patients later on in their professional life. The aim of this study was to explore Nordic pharmacy students' attitudes to communication skills learning, and the associations between those attitudes and various student characteristics. A cross-sectional questionnaire-based study was conducted in 11 Nordic pharmacy schools between April 2015 and January 2016. The overall response rate for the final study population was 77% (367 out of 479 students). Pharmacy students who had fulfilled all mandatory communication training and most of their pharmacy practical experience periods were included. The communication skills attitudes scale was the main outcome. Linear regression models were fitted with the outcome variable and various student characteristics as the predictors, using generalized estimating equations to account for clustering within pharmacy schools. Nordic pharmacy students in general have moderately positive attitudes towards learning communication skills. Positive attitudes towards learning communication skills among pharmacy students were associated with being female (β adjusted 0.42, 95% CI 0.20 to 0.63, p communication skills improvement (β adjusted 0.50, 95% CI 0.30 to 0.71, pcommunication skills are not the result of personality (β adjusted  -0.24, 95% CI -0.44 to -0.04, p=0.017). The study provides important information for faculty members responsible for curriculum improvements and teachers to refine their teaching of communication skills. From this, the teaching can be better tailored to suit different students. The students' chances of being able to effectively help patients in the future will be increased by that. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Low Cognitive Impulsivity Is Associated with Better Gain and Loss Learning in a Probabilistic Decision-Making Task

    Science.gov (United States)

    Cáceres, Pablo; San Martín, René

    2017-01-01

    Many advances have been made over the last decades in describing, on the one hand, the link between reward-based learning and decision-making, and on the other hand, the link between impulsivity and decision-making. However, the association between reward-based learning and impulsivity remains poorly understood. In this study, we evaluated the association between individual differences in loss-minimizing and gain-maximizing behavior in a learning-based probabilistic decision-making task and individual differences in cognitive impulsivity. We found that low cognitive impulsivity was associated both with a better performance minimizing losses and maximizing gains during the task. These associations remained significant after controlling for mathematical skills and gender as potential confounders. We discuss potential mechanisms through which cognitive impulsivity might interact with reward-based learning and decision-making. PMID:28261137

  10. Learning from the learning curve: factors associated with successful endoscopic correction of vesicoureteral reflux using dextranomer/hyaluronic acid copolymer.

    Science.gov (United States)

    Dave, Sumit; Lorenzo, Armando J; Khoury, Antoine E; Braga, Luis H P; Skeldon, Sean J; Suoub, Mohammed; Farhat, Walid; Pippi Salle, João L; Bägli, Darius J

    2008-10-01

    Conflicting reports exist regarding the parameters guiding successful correction of vesicoureteral reflux using dextranomer/hyaluronic acid copolymer. We performed logistic regression analysis to evaluate the effect of injected volume while adjusting for other factors potentially associated with success following dextranomer/hyaluronic acid copolymer injection. Between July 2003 and June 2006, 126 consecutive patients (34 boys and 92 girls) with a mean +/- SD age of 6.5 +/- 3.7 years with primary vesicoureteral reflux (196 refluxing ureters) underwent injection for febrile urinary tract infections. Success was defined as complete reflux resolution. Age, gender, laterality, preoperative vesicoureteral reflux grade, surgeon experience, dextranomer/hyaluronic acid copolymer volume, time to surgery from initial presentation and preoperative treatment for lower urinary tract symptoms were analyzed. Vesicoureteral reflux grade was I to V in 7 (3.5%), 53 (27%), 91 (46.4%), 30 (15.3%) and 15 renal units (7.6%), respectively. The success rate after 1 injection was 50% by patient and 59.2% by ureter. Mean injected volume was 0.9 +/- 0.27 ml in those who had a successful injection vs 0.67 +/- 0.24 ml in those in whom injection failed (p hyaluronic acid copolymer compared to 31.7% with less than 0.8 ml. Multivariate analysis confirmed that higher dextranomer/hyaluronic acid copolymer volume (p = 0.001), lower preoperative grade (p = 0.013), surgeon experience (p = 0.025) and treatment for lower urinary tract symptoms (p = 0.009) were associated with successful correction of vesicoureteral reflux. Our analysis strengthens the previously reported association of surgeon experience and vesicoureteral reflux grade with successful endoscopic vesicoureteral reflux correction. The data also revealed an association between injected volume and vesicoureteral reflux correction even while controlling for other variables, highlighting its importance as a true success modifier.

  11. Decomposing experience-driven attention: opposite attentional effects of previously predictive cues

    Science.gov (United States)

    Lin, Zhicheng; Lu, Zhong-Lin; He, Sheng

    2016-01-01

    A central function of the brain is to track the dynamic statistical regularities in the environment—such as what predicts what over time. How does this statistical learning process alter sensory and attentional processes? Drawing upon animal conditioning and predictive coding, we developed a learning procedure that revealed two distinct components through which prior learning-experience controls attention. During learning, a visual search task was used in which the target randomly appeared at one of several locations but always inside an encloser of a particular color—the learned color served to direct attention to the target location. During test, the color no longer predicted the target location. When the same search task was used in the subsequent test, we found that the learned color continued to attract attention despite the behavior being counterproductive for the task and despite the presence of a completely predictive cue. However, when tested with a flanker task that had minimal location uncertainty—the target was at the fixation surrounded by a distractor—participants were better at ignoring distractors in the learned color than other colors. Evidently, previously predictive cues capture attention in the same search task but can be better suppressed in a flanker task. These results demonstrate opposing components—capture and inhibition—in experience-driven attention, with their manifestations crucially dependent on task context. We conclude that associative learning enhances context-sensitive top-down modulation while reduces bottom-up sensory drive and facilitates suppression, supporting a learning-based predictive coding account. PMID:27068051

  12. Rapid learning of associations between sound and action through observed movement. A TMS study.

    Science.gov (United States)

    Launay, Jacques; Dean, Roger T; Bailes, Freya

    2016-03-01

    Research has established that there is a cognitive link between perception and production of the same movement. However, there has been relatively little research into the relevance of this for non-expert perceivers, such as music listeners who do not play instruments themselves. In two experiments we tested whether participants can quickly learn new associations between sounds and observed movement without performing those movements themselves. We measured motor evoked potentials (MEPs) in the first dorsal interosseous muscle of participants' right hands while test tones were heard and single transcranial magnetic stimulation (TMS) pulses were used to trigger motor activity. In Experiment 1 participants in a 'human' condition (n=4) learnt to associate the test tone with finger movement of the experimenter, while participants in a 'computer' condition (n=4) learnt that the test tone was triggered by a computer. Participants in the human condition showed a larger increase in MEPs compared with those in the computer condition. In a second experiment pairing between sounds and movement occurred without participants repeatedly observing the movement and we found no such difference between the human (n=4) and computer (n=4) conditions. These results suggest that observers can quickly learn to associate sound with movement, so it should not be necessary to have played an instrument to experience some motor resonance when hearing that instrument.

  13. [Optogenetic activation of dorsal hippocampal astrocytic Rac1 blocks the learning of associative memory].

    Science.gov (United States)

    Guo, Xiao-Mu; Liao, Zhao-Hui; Tao, Ye-Zheng; Wang, Fei-Fei; Ma, Lan

    2017-06-25

    Rac1 belongs to the family of Rho GTPases, and plays important roles in the brain function. It affects the cell migration and axon guidance via regulating the cytoskeleton and cellular morphology. However, the effect of its dynamic activation in regulating physiological function remains unclear. Recently, a photoactivatable analogue of Rac1 (PA-Rac1) has been developed, allowing the activation of Rac1 by the specific wavelength of light in living cells. Thus, we constructed recombinant adeno-associated virus (AAV) of PA-Rac1 and its light-insensitive mutant PA-Rac1-C450A under the control of the mouse glial fibrillary acidic protein (mGFAP) promoter to manipulate Rac1 activity in astrocytes by optical stimulation. Primary culture of hippocampal astrocytes was infected with the recombinant AAV-PA-Rac1 or AAV-PA-Rac1-C450A. Real-time fluorescence imaging showed that the cell membrane of the astrocyte expressing PA-Rac1 protruded near the light spot, while the astrocyte expressing PA-Rac1-C450A did not. We injected AAV-PA-Rac1 and AAV-PA-Rac1-C450A into dorsal hippocampus to investigate the role of the activation of Rac1 in regulating the associative learning. With optical stimulation, the PA-Rac1 group, rather than the PA-Rac1-C450A group, showed slower learning curve during the fear conditioning compared with the control group, indicating that activating astrocytic Rac1 blocks the formation of contextual memory. Our data suggest that the activation of Rac1 in dorsal hippocampal astrocyte plays an important role in the associative learning.

  14. Individual personality differences in goats predict their performance in visual learning and non-associative cognitive tasks.

    Science.gov (United States)

    Nawroth, Christian; Prentice, Pamela M; McElligott, Alan G

    2017-01-01

    Variation in common personality traits, such as boldness or exploration, is often associated with risk-reward trade-offs and behavioural flexibility. To date, only a few studies have examined the effects of consistent behavioural traits on both learning and cognition. We investigated whether certain personality traits ('exploration' and 'sociability') of individuals were related to cognitive performance, learning flexibility and learning style in a social ungulate species, the goat (Capra hircus). We also investigated whether a preference for feature cues rather than impaired learning abilities can explain performance variation in a visual discrimination task. We found that personality scores were consistent across time and context. Less explorative goats performed better in a non-associative cognitive task, in which subjects had to follow the trajectory of a hidden object (i.e. testing their ability for object permanence). We also found that less sociable subjects performed better compared to more sociable goats in a visual discrimination task. Good visual learning performance was associated with a preference for feature cues, indicating personality-dependent learning strategies in goats. Our results suggest that personality traits predict the outcome in visual discrimination and non-associative cognitive tasks in goats and that impaired performance in a visual discrimination tasks does not necessarily imply impaired learning capacities, but rather can be explained by a varying preference for feature cues. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Fusing Data Mining, Machine Learning and Traditional Statistics to Detect Biomarkers Associated with Depression

    Science.gov (United States)

    Dipnall, Joanna F.

    2016-01-01

    Background Atheoretical large-scale data mining techniques using machine learning algorithms have promise in the analysis of large epidemiological datasets. This study illustrates the use of a hybrid methodology for variable selection that took account of missing data and complex survey design to identify key biomarkers associated with depression from a large epidemiological study. Methods The study used a three-step methodology amalgamating multiple imputation, a machine learning boosted regression algorithm and logistic regression, to identify key biomarkers associated with depression in the National Health and Nutrition Examination Study (2009–2010). Depression was measured using the Patient Health Questionnaire-9 and 67 biomarkers were analysed. Covariates in this study included gender, age, race, smoking, food security, Poverty Income Ratio, Body Mass Index, physical activity, alcohol use, medical conditions and medications. The final imputed weighted multiple logistic regression model included possible confounders and moderators. Results After the creation of 20 imputation data sets from multiple chained regression sequences, machine learning boosted regression initially identified 21 biomarkers associated with depression. Using traditional logistic regression methods, including controlling for possible confounders and moderators, a final set of three biomarkers were selected. The final three biomarkers from the novel hybrid variable selection methodology were red cell distribution width (OR 1.15; 95% CI 1.01, 1.30), serum glucose (OR 1.01; 95% CI 1.00, 1.01) and total bilirubin (OR 0.12; 95% CI 0.05, 0.28). Significant interactions were found between total bilirubin with Mexican American/Hispanic group (p = 0.016), and current smokers (p<0.001). Conclusion The systematic use of a hybrid methodology for variable selection, fusing data mining techniques using a machine learning algorithm with traditional statistical modelling, accounted for missing data and

  16. Global hypoxia induced impairment in learning and spatial memory is associated with precocious hippocampal aging.

    Science.gov (United States)

    Biswal, Suryanarayan; Sharma, Deepti; Kumar, Kushal; Nag, Tapas Chandra; Barhwal, Kalpana; Hota, Sunil Kumar; Kumar, Bhuvnesh

    2016-09-01

    Both chronological aging and chronic hypoxia stress have been reported to cause degeneration of hippocampal CA3 neurons and spatial memory impairment through independent pathways. However, the possible occurrence of precocious biological aging on exposure to single episode of global hypoxia resulting in impairment of learning and memory remains to be established. The present study thus aimed at bridging this gap in existing literature on hypoxia induced biological aging. Male Sprague Dawley rats were exposed to simulated hypobaric hypoxia (25,000ft) for different durations and were compared with aged rats. Behavioral studies in Morris Water Maze showed decline in learning abilities of both chronologically aged as well as hypoxic rats as evident from increased latency and pathlength to reach target platform. These behavioral changes in rats exposed to global hypoxia were associated with deposition of lipofuscin and ultrastructural changes in the mitochondria of hippocampal neurons that serve as hallmarks of aging. A single episode of chronic hypobaric hypoxia exposure also resulted in the up-regulation of pro-aging protein, S100A9 and down regulation of Tau, SNAP25, APOE and Sod2 in the hippocampus similar to that in aged rats indicating hypoxia induced accelerated aging. The present study therefore provides evidence for role of biological aging of hippocampal neurons in hypoxia induced impairment of learning and memory. Copyright © 2016. Published by Elsevier Inc.

  17. Long-term associative learning predicts verbal short-term memory performance.

    Science.gov (United States)

    Jones, Gary; Macken, Bill

    2018-02-01

    Studies using tests such as digit span and nonword repetition have implicated short-term memory across a range of developmental domains. Such tests ostensibly assess specialized processes for the short-term manipulation and maintenance of information that are often argued to enable long-term learning. However, there is considerable evidence for an influence of long-term linguistic learning on performance in short-term memory tasks that brings into question the role of a specialized short-term memory system separate from long-term knowledge. Using natural language corpora, we show experimentally and computationally that performance on three widely used measures of short-term memory (digit span, nonword repetition, and sentence recall) can be predicted from simple associative learning operating on the linguistic environment to which a typical child may have been exposed. The findings support the broad view that short-term verbal memory performance reflects the application of long-term language knowledge to the experimental setting.

  18. Dopamine Regulates Aversive Contextual Learning and Associated In Vivo Synaptic Plasticity in the Hippocampus

    Directory of Open Access Journals (Sweden)

    John I. Broussard

    2016-03-01

    Full Text Available Dopamine release during reward-driven behaviors influences synaptic plasticity. However, dopamine innervation and release in the hippocampus and its role during aversive behaviors are controversial. Here, we show that in vivo hippocampal synaptic plasticity in the CA3-CA1 circuit underlies contextual learning during inhibitory avoidance (IA training. Immunohistochemistry and molecular techniques verified sparse dopaminergic innervation of the hippocampus from the midbrain. The long-term synaptic potentiation (LTP underlying the learning of IA was assessed with a D1-like dopamine receptor agonist or antagonist in ex vivo hippocampal slices and in vivo in freely moving mice. Inhibition of D1-like dopamine receptors impaired memory of the IA task and prevented the training-induced enhancement of both ex vivo and in vivo LTP induction. The results indicate that dopamine-receptor signaling during an aversive contextual task regulates aversive memory retention and regulates associated synaptic mechanisms in the hippocampus that likely underlie learning.

  19. Distinct effects of dopamine vs STN stimulation therapies in associative learning and retention in Parkinson disease.

    Science.gov (United States)

    Ventre-Dominey, Jocelyne; Mollion, Hélène; Thobois, Stephane; Broussolle, Emmanuel

    2016-04-01

    Evidence has been provided in Parkinson's disease patients of cognitive impairments including visual memory and learning which can be partially compensated by dopamine medication or subthalamic nucleus stimulation. The effects of these two therapies can differ according to the learning processes involving the dorsal vs ventral part of the striatum. Here we aimed to investigate and compare the outcomes of dopamine vs stimulation treatment in Parkinson patient's ability to acquire and maintain over successive days their performance in visual working memory. Parkinson patients performed conditional associative learning embedded in visual (spatial and non spatial) working memory tasks over two consecutive days either ON or OFF dopaminergic drugs or STN stimulation depending on the group of patients studied. While Parkinson patients were more accurate and faster in memory tasks ON vs OFF stimulation independent of the day of testing, performance in medicated patients differed depending on the medication status during the initial task acquisition. Patients who learnt the task ON medication the first day were able to maintain or even improve their memory performance both OFF and ON medication on the second day after consolidation. These effects were observed only in patients with dopamine replacement with or without motor fluctuations. This enhancement in memory performance after having learnt under dopamine medication and not under STN stimulation was mostly significant in visuo-spatial working memory tasks suggesting that dopamine replacement in the depleted dorsal striatum is essential for retention and consolidation of learnt skill. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Explaining Compound Generalization in Associative and Causal Learning Through Rational Principles of Dimensional Generalization

    Science.gov (United States)

    Soto, Fabian A.; Gershman, Samuel J.; Niv, Yael

    2014-01-01

    How do we apply learning from one situation to a similar, but not identical, situation? The principles governing the extent to which animals and humans generalize what they have learned about certain stimuli to novel compounds containing those stimuli vary depending on a number of factors. Perhaps the best studied among these factors is the type of stimuli used to generate compounds. One prominent hypothesis is that different generalization principles apply depending on whether the stimuli in a compound are similar or dissimilar to each other. However, the results of many experiments cannot be explained by this hypothesis. Here we propose a rational Bayesian theory of compound generalization that uses the notion of consequential regions, first developed in the context of rational theories of multidimensional generalization, to explain the effects of stimulus factors on compound generalization. The model explains a large number of results from the compound generalization literature, including the influence of stimulus modality and spatial contiguity on the summation effect, the lack of influence of stimulus factors on summation with a recovered inhibitor, the effect of spatial position of stimuli on the blocking effect, the asymmetrical generalization decrement in overshadowing and external inhibition, and the conditions leading to a reliable external inhibition effect. By integrating rational theories of compound and dimensional generalization, our model provides the first comprehensive computational account of the effects of stimulus factors on compound generalization, including spatial and temporal contiguity between components, which have posed longstanding problems for rational theories of associative and causal learning. PMID:25090430

  1. Reversal learning strategy in adolescence is associated with prefrontal cortex activation.

    Science.gov (United States)

    Boehme, Rebecca; Lorenz, Robert C; Gleich, Tobias; Romund, Lydia; Pelz, Patricia; Golde, Sabrina; Flemming, Eva; Wold, Andrew; Deserno, Lorenz; Behr, Joachim; Raufelder, Diana; Heinz, Andreas; Beck, Anne

    2017-01-01

    Adolescence is a critical maturation period for human cognitive control and executive function. In this study, a large sample of adolescents (n = 85) performed a reversal learning task during functional magnetic resonance imaging. We analyzed behavioral data using a reinforcement learning model to provide individually fitted parameters and imaging data with regard to reward prediction errors (PE). Following a model-based approach, we formed two groups depending on whether individuals tended to update expectations predominantly for the chosen stimulus or also for the unchosen one. These groups significantly differed in their problem behavior score obtained using the child behavior checklist (CBCL) and in a measure of their developmental stage. Imaging results showed that dorsolateral striatal areas covaried with PE. Participants who relied less on learning based on task structure showed less prefrontal activation compared with participants who relied more on task structure. An exploratory analysis revealed that PE-related activity was associated with pubertal development in prefrontal areas, insula and anterior cingulate. These findings support the hypothesis that the prefrontal cortex is implicated in mediating flexible goal-directed behavioral control. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  2. Predicting central line-associated bloodstream infections and mortality using supervised machine learning.

    Science.gov (United States)

    Parreco, Joshua P; Hidalgo, Antonio E; Badilla, Alejandro D; Ilyas, Omar; Rattan, Rishi

    2018-02-21

    The purpose of this study was to compare machine learning techniques for predicting central line-associated bloodstream infection (CLABSI). The Multiparameter Intelligent Monitoring in Intensive Care III database was queried for all ICU admissions. The variables included six different severities of illness scores calculated on the first day of ICU admission with their components and comorbidities. The outcomes of interest were in-hospital mortality, central line placement, and CLABSI. Predictive models were created for these outcomes using classifiers with different algorithms: logistic regression, gradient boosted trees, and deep learning. There were 57,786 total hospital admissions and the mortality rate was 10.1%. There were 38.4% patients with a central line and the rate of CLABSI was 1.5%. The classifiers using deep learning performed with the highest AUC for mortality, 0.885±0.010 (p<0.01) and central line placement, 0.816±0.006 (p<0.01). The classifier using logistic regression for predicting CLABSI performed with an AUC of 0.722±0.048 (p<0.01). This study demonstrates models for identifying patients who will develop CLABSI. Early identification of these patients has implications for quality, cost, and outcome improvements. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Considerations for automated machine learning in clinical metabolic profiling: Altered homocysteine plasma concentration associated with metformin exposure.

    Science.gov (United States)

    Orlenko, Alena; Moore, Jason H; Orzechowski, Patryk; Olson, Randal S; Cairns, Junmei; Caraballo, Pedro J; Weinshilboum, Richard M; Wang, Liewei; Breitenstein, Matthew K

    2018-01-01

    With the maturation of metabolomics science and proliferation of biobanks, clinical metabolic profiling is an increasingly opportunistic frontier for advancing translational clinical research. Automated Machine Learning (AutoML) approaches provide exciting opportunity to guide feature selection in agnostic metabolic profiling endeavors, where potentially thousands of independent data points must be evaluated. In previous research, AutoML using high-dimensional data of varying types has been demonstrably robust, outperforming traditional approaches. However, considerations for application in clinical metabolic profiling remain to be evaluated. Particularly, regarding the robustness of AutoML to identify and adjust for common clinical confounders. In this study, we present a focused case study regarding AutoML considerations for using the Tree-Based Optimization Tool (TPOT) in metabolic profiling of exposure to metformin in a biobank cohort. First, we propose a tandem rank-accuracy measure to guide agnostic feature selection and corresponding threshold determination in clinical metabolic profiling endeavors. Second, while AutoML, using default parameters, demonstrated potential to lack sensitivity to low-effect confounding clinical covariates, we demonstrated residual training and adjustment of metabolite features as an easily applicable approach to ensure AutoML adjustment for potential confounding characteristics. Finally, we present increased homocysteine with long-term exposure to metformin as a potentially novel, non-replicated metabolite association suggested by TPOT; an association not identified in parallel clinical metabolic profiling endeavors. While warranting independent replication, our tandem rank-accuracy measure suggests homocysteine to be the metabolite feature with largest effect, and corresponding priority for further translational clinical research. Residual training and adjustment for a potential confounding effect by BMI only slightly modified

  4. COMT Val158Met genotype is associated with reward learning: A replication study and meta-analysis

    Science.gov (United States)

    Corral-Frías, Nadia S.; Pizzagalli, Diego A.; Carré, Justin; Michalski, Lindsay J; Nikolova, Yuliya S.; Perlis, Roy H.; Fagerness, Jesen; Lee, Mary R.; Conley, Emily Drabant; Lancaster, Thomas M.; Haddad, Stephen; Wolf, Aaron; Smoller, Jordan W.; Hariri, Ahmad R.; Bogdan, Ryan

    2016-01-01

    Identifying mechanisms through which individual differences in reward learning emerge offers an opportunity to understand both a fundamental form of adaptive responding as well as etiological pathways through which aberrant reward learning may contribute to maladaptive behaviors and psychopathology. One candidate mechanism through which individual differences in reward learning may emerge is variability in dopaminergic reinforcement signaling. A common functional polymorphism within the catechol-O-methyl transferase gene (COMT; rs4680, Val158Met) has been linked to reward learning where homozygosity for the Met allele (associated with heightened prefrontal dopamine function and decreased dopamine synthesis in the midbrain) has been associated with relatively increased reward learning. Here, we used a probabilistic reward learning task to asses response bias, a behavioral form of reward learning, across 3 separate samples that were combined for analyses (age: 21.80 ± 3.95; n=392; 268 female; European-American, n=208). We replicate prior reports that COMT rs4680 Met allele homozygosity is associated with increased reward learning in European-American participants (β=0.20, t= 2.75, p< 0.01; ΔR2= 0.04). Moreover, a meta-analysis of 4 studies, including the current one, confirmed the association between COMT rs4680 genotype and reward learning (95% CI −0.11 to −0.03; z=3.2; p<0.01). These results suggest that variability in dopamine signaling associated with COMT rs4680 influences individual differences in reward which may potentially contribute to psychopathology characterized by reward dysfunction. PMID:27138112

  5. Associations between otitis media and child behavioural and learning difficulties: Results from a Danish cohort.

    Science.gov (United States)

    Niclasen, J; Obel, C; Homøe, P; Kørvel-Hanquist, A; Dammeyer, J

    2016-05-01

    Findings from studies investigating early childhood episodes of otitis media (OM) and developmental outcomes are inconclusive. This may in part be because large-scale prospective studies controlling for relevant confounding factors are sparse. The present study investigates associations between OM in early childhood and later behavioural and learning difficulties controlling for relevant confounding factors. The study applied data from the Aarhus Birth Cohort's 10-12-year-old follow-up (N=7578). Associations between retrospective parent-reported OM (no OM; 1-3 episodes of OM with/without tympanostomy tubes; 4+ OM episodes without tympanostomy tubes and; 4+ OM episodes with tympanostomy tubes) one the one hand, and parent- and teacher-reported scores on the Strengths and Difficulties Questionnaire (SDQ) and parent-reported academic difficulties on the other hand, were investigated. The following variables were controlled for: parental educational level, maternal and paternal school problems, parental post-natal smoking, breastfeeding, and age at which the child started walking. All analyses were stratified by gender. Large differences in background characteristics were observed for the group of children with 4+ OM episodes with tympanostomy tubes compared to the no OM group. After controlling for relevant confounders, negative associations were consistently observed for the group of children with 4+ episodes of OM with tympanostomy tubes compared to the group of children without OM. This was particularly so for girls. The findings suggest an association between 4+ episodes of early OM with tympanostomy tubes and behavioural and learning difficulties later in childhood. The large inter-group differences, i.e. impact of residual and unmeasured confounding factors, may in part explain the observed associations and underline the need to include these in future studies. Copyright © 2016. Published by Elsevier Ireland Ltd.

  6. A Comparison Between Denaturing Gradient Gel Electrophoresis and Denaturing High Performance Liquid Chromatography in Detecting Mutations in Genes Associated with Hereditary Non-Polyposis Colorectal Cancer (HNPCC and the Identification of 9 New Mutations Previously Unidentified by DGGE

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    Meldrum Cliff J

    2003-12-01

    Full Text Available Abstract Denaturing high performance liquid chromatography is a relatively new method by which heteroduplex structures formed during the PCR amplification of heterozygote samples can be rapidly identified. The use of this technology for mutation detection in hereditary non-polyposis colorectal cancer (HNPCC has the potential to appreciably shorten the time it takes to analyze genes associated with this disorder. Prior to acceptance of this method for screening genes associated with HNPCC, assessment of the reliability of this method should be performed. In this report we have compared mutation and polymorphism detection by denaturing gradient gel electrophoresis (DGGE with denaturing high performance liquid chromatography (DHPLC in a set of 130 families. All mutations/polymorphisms representing base substitutions, deletions, insertions and a 23 base pair inversion were detected by DHPLC whereas DGGE failed to identify four single base substitutions and a single base pair deletion. In addition, we show that DHPLC has been used for the identification of 5 different mutations in exon 7 of hMSH2 that could not be detected by DGGE. From this study we conclude that DHPLC is a more effective and rapid alternative to the detection of mutations in hMSH2 and hMLH1 with the same or better accuracy than DGGE. Furthermore, this technique offers opportunities for automation, which have not been realised for the majority of other methods of gene analysis.

  7. Soil transmitted helminth infections are not associated with compromised antibody responses to previously administered measles and tetanus vaccines among HIV-1 infected, ART naïve Kenyan adults

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    Helen L. Storey

    2017-02-01

    Full Text Available In many regions of sub-Saharan Africa, both HIV and helminth infections are prevalent. HIV-1 (human immunodeficiency virus type 1 and helminth infections can both compromise immune responses in humans. To determine whether the presence of helminth infection or the treatment of helminth infection alters unstimulated vaccine responses among HIV-1 infected individuals, we conducted two nested serologic studies. Blood samples were collected for HIV disease monitoring and vaccine-specific serologic assays, while stool was evaluated by direct microscopy methods. We compared antibody responses to measles and tetanus vaccines in helminth-infected (Ascaris, Trichuris, hookworm and/or Schistosoma mansoni and uninfected adults 18 years and older (n = 100. We also compared measles and tetanus antibody responses in Ascaris only-infected adults receiving 400 mg albendazole daily for 3 days (n = 16 vs. placebo (n = 19 in a separate study. In both cohorts, over 70% of participants had measles and tetanus responses above the protective threshold. Prevalence of measles responses were similar between helminth-infected and uninfected individuals (82%, 95% CI: 71–93% vs 72%, 95% CI: 59–85%, as well as log10 tetanus antibody levels (−0.133 IU/mL vs −0.190 IU/mL, p > 0.05, and did not differ by helminth species. In the Ascaris-infected cohort, changes in measles responses and tetanus responses did not differ between those who received anthelminthic vs. placebo (p > 0.05 for both. In these studies, neither helminth infection, nor deworming, appeared to affect previously administered vaccine responsiveness in HIV-1 infected, ART naïve, adults in Kenya.

  8. Individual differences in personality in laying hens are related to learning a colour cue association.

    Science.gov (United States)

    de Haas, Elske N; Lee, Caroline; Hernandez, Carlos E; Naguib, Marc; Rodenburg, T Bas

    2017-01-01

    Personality can influence how animals perceive and learn cues. The behaviour and physiological responses animals show during stressful events is indicative of their personality. Acute induced stress prior to a cognitive test are known to affect the judgement of a stimulus, but personality of an individual could also affect learning of a specific cognitive paradigm. Here, we assessed if adult laying hens' behaviour and physiological responses, as indicators of their personality, were related to their cognitive performance. We assessed their behavioural responses to a tonic immobility test, an open field test, and a manual restraint test, and measured plasma corticosterone levels after manual restraint. After that, hens (n=20) were trained in a pre-set training schedule to associate a colour-cue with a reward. In a two-choice go-go test, hens needed to choose between a baited or non-baited food container displayed randomly on the left or right side of an arena. Success in learning was related to personality, with better performance of hens which showed a reactive personality type by a long latency to walk, struggle or vocalize during the tests. Only eight out of 20 hens reached the training criteria. The non-learners showed a strong side preference during all training days. Side preferences were strong in hens with high levels of plasma corticosterone and with a long duration of tonic immobility, indicating that fearful, stress-sensitive hens are more prone to develop side biases. Our results show that learning can be hindered by side biases, and fearful animals with a more proactive personality type are more sensitive to develop such biases. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Health Professions Students’ Lifelong Learning Orientation: Associations with Information Skills and Self Efficacy

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    Misa Mi

    2016-04-01

    Full Text Available Objective – This study aimed to investigate the relationships among health professions students’ lifelong learning orientation, self-assessed information skills, and information self-efficacy. Methods – This was a descriptive study with a cross-sectional research design. Participants included 850 nursing students and 325 medical students. A total of 419 students responded to a survey questionnaire that was comprised of 3 parts: demographic information, the Jefferson Scale of Lifelong Learning (JeffSLL-HPS, and an information self-efficacy scale. Results – Findings of the study show a significant correlation between students’ lifelong learning orientation and information self-efficacy. Average JeffSLL-HPS total scores for undergraduate nursing students (M = 41.84 were significantly lower than the scores for graduate nursing students (M = 46.20. Average information self-efficacy total scores were significantly lower for undergraduate nursing students (M = 63.34 than the scores for graduate nursing students (M = 65.97. There were no significant differences among cohorts of medical students for JeffSLL-HPS total scores. However, for information self-efficacy, first year medical students (M = 55.62 and second year medical students (M = 58.00 had significantly lower scores than third/fourth year students (M = 64.42. Conclusion – Findings from the study suggest implications for librarians seeking ways to advance the value and utility of information literacy instruction in educational curricula. As such instruction has the potential to lead to high levels of information self-efficacy associated with lifelong learning; various strategies could be developed and incorporated into the instruction to cultivate students’ information self-efficacy.

  10. The effects of vitamin C on hypothyroidism-associated learning and memory impairment in juvenile rats.

    Science.gov (United States)

    Beheshti, Farimah; Karimi, Sareh; Vafaee, Farzaneh; Shafei, Mohammad Naser; Sadeghnia, Hamid Reza; Hadjzadeh, Mosa Al Reza; Hosseini, Mahmoud

    2017-06-01

    In this study the effects of Vitamin C (Vit C) on hypothyroidism-associated learning and memory impairment in juvenile rats was investigated. The pregnant rats were kept in separate cages. After delivery, they were randomly divided into six groups and treated: (1) Control; (2) Propylthiouracil (PTU) which 0.005% PTU in their drinking; (3-5) Propylthiouracil- Vit C groups; besides PTU, dams in these groups received 10, 100 and 500 mg/kg Vit C respectively, (6) one group as a positive control; the intact rats received an effective dose, 100 mg/kg Vit. C. After delivery, the pups were continued to receive the experimental treatments in their drinking water up to 56th day of their life. Ten male offspring of each group were randomly selected and tested in the Morris water maze (MWM) and passive avoidance (PA) which were started at 63th day (one week after stopping of the treatments). Brains were then removed for biochemical measurements. PTU increased time latency and traveled distance during 5 days in MWM while, reduced the spent time in target quadrant in MWM and step-trough latency (STL) in PA. PTU decreased thiol content, superoxide dismutase (SOD) and catalase (CAT) activities in the brain while, increased molondialdehyde (MDA). In MWM test, 10, 100 and 500 mg/kg Vit C reduced time latency and traveled distance without affecting the traveling speed during 5 days. All doses of Vit C increased the spent time in target quadrant in probe trail of MWM and also increased STL in PA test. Vit C increased thiol, SOD and CAT in the brain tissues while, reduced MDA. Results of present study confirmed the beneficial effects of Vit C on learning and memory. It also demonstrated that Vit C has protective effects on hypothyroidism-associated learning and memory impairment in juvenile rats which might be elucidated by the antioxidative effects.

  11. Motor imagery-based implicit sequence learning depends on the formation of stimulus-response associations.

    Science.gov (United States)

    Kraeutner, Sarah N; Gaughan, Theresa C; Eppler, Sarah N; Boe, Shaun G

    2017-07-01

    Implicit sequence learning (ISL) occurs without conscious awareness and is critical for skill acquisition. The extent to which ISL occurs is a function of exposure (i.e., total training time and/or sequence to noise ratio) to a repeated sequence, and thus the cognitive mechanism underlying ISL is the formation of stimulus-response associations. As the majority of ISL studies employ paradigms whereby individuals unknowingly physically practice a repeated sequence, the cognitive mechanism underlying ISL through motor imagery (MI), the mental rehearsal of movement, remains unknown. This study examined the cognitive mechanisms of MI-based ISL by probing the link between exposure and the resultant ISL. Seventy-two participants underwent MI-based practice of an ISL task following randomization to one of four conditions: 4 training blocks with a high (4-High) or low (4-Low) sequence to noise ratio, or 2 training blocks with a high (2-High) or low (2-Low) sequence to noise ratio. Reaction time differences (dRT) and effect sizes between repeated and random sequences assessed the extent of learning. All groups showed a degree of ISL, yet effect sizes indicated a greater degree of learning in groups with higher exposure (4-Low and 4-High). Findings indicate that the extent to which ISL occurs through MI is impacted by manipulations to total training time and the sequence to noise ratio. Overall, we show that the extent of ISL occurring through MI is a function of exposure, indicating that like physical practice, the cognitive mechanisms of MI-based ISL rely on the formation of stimulus response associations. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Information processing in illness representation: Implications from an associative-learning framework.

    Science.gov (United States)

    Lowe, Rob; Norman, Paul

    2017-03-01

    The common-sense model (Leventhal, Meyer, & Nerenz, 1980) outlines how illness representations are important for understanding adjustment to health threats. However, psychological processes giving rise to these representations are little understood. To address this, an associative-learning framework was used to model low-level process mechanics of illness representation and coping-related decision making. Associative learning was modeled within a connectionist network simulation. Two types of information were paired: Illness identities (indigestion, heart attack, cancer) were paired with illness-belief profiles (cause, timeline, consequences, control/cure), and specific illness beliefs were paired with coping procedures (family doctor, emergency services, self-treatment). To emulate past experience, the network was trained with these pairings. As an analogue of a current illness event, the trained network was exposed to partial information (illness identity or select representation beliefs) and its response recorded. The network (a) produced the appropriate representation profile (beliefs) for a given illness identity, (b) prioritized expected coping procedures, and (c) highlighted circumstances in which activated representation profiles could include self-generated or counterfactual beliefs. Encoding and activation of illness beliefs can occur spontaneously and automatically; conventional questionnaire measurement may be insensitive to these automatic representations. Furthermore, illness representations may comprise a coherent set of nonindependent beliefs (a schema) rather than a collective of independent beliefs. Incoming information may generate a "tipping point," dramatically changing the active schema as a new illness-knowledge set is invoked. Finally, automatic activation of well-learned information can lead to the erroneous interpretation of illness events, with implications for [inappropriate] coping efforts. (PsycINFO Database Record (c) 2017 APA, all

  13. Learning-enhanced coupling between ripple oscillations in association cortices and hippocampus.

    Science.gov (United States)

    Khodagholy, Dion; Gelinas, Jennifer N; Buzsáki, György

    2017-10-20

    Consolidation of declarative memories requires hippocampal-neocortical communication. Although experimental evidence supports the role of sharp-wave ripples in transferring hippocampal information to the neocortex, the exact cortical destinations and the physiological mechanisms of such transfer are not known. We used a conducting polymer-based conformable microelectrode array (NeuroGrid) to record local field potentials and neural spiking across the dorsal cortical surface of the rat brain, combined with silicon probe recordings in the hippocampus, to identify candidate physiological patterns. Parietal, midline, and prefrontal, but not primary cortical areas, displayed localized ripple (100 to 150 hertz) oscillations during sleep, concurrent with hippocampal ripples. Coupling between hippocampal and neocortical ripples was strengthened during sleep following learning. These findings suggest that ripple-ripple coupling supports hippocampal-association cortical transfer of memory traces. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  14. Mild maternal stress disrupts associative learning and increases aggression in offspring.

    Science.gov (United States)

    Eaton, L; Edmonds, E J; Henry, T B; Snellgrove, D L; Sloman, K A

    2015-05-01

    Maternal stress has been shown to affect behaviour of offspring in a wide range of animals, but this evidence has come from studies that exposed gestating mothers to acute or severe stressors, such as restraint or exposure to synthetic stress hormones. Here we show that exposure of mothers to even a mild stressor reduces associative learning and increases aggression in offspring. Female guppies were exposed to routine husbandry procedures that produced only a minimal, non-significant, elevation of the stress hormone cortisol. In contrast to controls, offspring from mothers that experienced this mild stress failed to learn to associate a colour cue and food reward, and showed a greater amount of inter-individual variation in behaviour compared with control offspring. This mild stress also resulted in offspring that were more aggressive towards their own mirror image than controls. While it is possible that these results could represent the transmission of beneficial maternal characteristics to offspring born into unpredictable environments, the potential for mild maternal stress to affect offspring performance also has important implications for research into the trans-generational effects of stress. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Brain-like associative learning using a nanoscale non-volatile phase change synaptic device array

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    Sukru Burc Eryilmaz

    2014-07-01

    Full Text Available Recent advances in neuroscience together with nanoscale electronic device technology have resulted in huge interests in realizing brain-like computing hardwares using emerging nanoscale memory devices as synaptic elements. Although there has been experimental work that demonstrated the operation of nanoscale synaptic element at the single device level, network level studies have been limited to simulations. In this work, we demonstrate, using experiments, array level associative learning using phase change synaptic devices connected in a grid like configuration similar to the organization of the biological brain. Implementing Hebbian learning with phase change memory cells, the synaptic grid was able to store presented patterns and recall missing patterns in an associative brain-like fashion. We found that the system is robust to device variations, and large variations in cell resistance states can be accommodated by increasing the number of training epochs. We illustrated the tradeoff between variation tolerance of the network and the overall energy consumption, and found that energy consumption is decreased significantly for lower variation tolerance.

  16. Pathological gamblers are more vulnerable to the illusion of control in a standard associative learning task

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    Cristina eOrgaz

    2013-06-01

    Full Text Available An illusion of control is said to occur when a person believes that he or she controls an outcome that is uncontrollable. Pathological gambling has often been related to an illusion of control, but the assessment of the illusion has generally used introspective methods in domain-specific (i.e., gambling situations. The illusion of control of pathological gamblers, however, could be a more general problem, affecting other aspects of their daily life. Thus, we tested them using a standard associative learning task which is known to produce illusions of control in most people under certain conditions. The results showed that the illusion was significantly stronger in pathological gamblers than in a control undiagnosed sample. This suggests (a that the experimental tasks used in basic associative learning research could be used to detect illusions of control in gamblers in a more indirect way, as compared to introspective and domain-specific questionnaires; and (b, that in addition to gambling-specific problems, pathological gamblers may have a higher-than-normal illusion of control in their daily life.

  17. Automatic association of chats and video tracks for activity learning and recognition in aerial video surveillance.

    Science.gov (United States)

    Hammoud, Riad I; Sahin, Cem S; Blasch, Erik P; Rhodes, Bradley J; Wang, Tao

    2014-10-22

    We describe two advanced video analysis techniques, including video-indexed by voice annotations (VIVA) and multi-media indexing and explorer (MINER). VIVA utilizes analyst call-outs (ACOs) in the form of chat messages (voice-to-text) to associate labels with video target tracks, to designate spatial-temporal activity boundaries and to augment video tracking in challenging scenarios. Challenging scenarios include low-resolution sensors, moving targets and target trajectories obscured by natural and man-made clutter. MINER includes: (1) a fusion of graphical track and text data using probabilistic methods; (2) an activity pattern learning framework to support querying an index of activities of interest (AOIs) and targets of interest (TOIs) by movement type and geolocation; and (3) a user interface to support streaming multi-intelligence data processing. We also present an activity pattern learning framework that uses the multi-source associated data as training to index a large archive of full-motion videos (FMV). VIVA and MINER examples are demonstrated for wide aerial/overhead imagery over common data sets affording an improvement in tracking from video data alone, leading to 84% detection with modest misdetection/false alarm results due to the complexity of the scenario. The novel use of ACOs and chat Sensors 2014, 14 19844 messages in video tracking paves the way for user interaction, correction and preparation of situation awareness reports.

  18. Automatic Association of Chats and Video Tracks for Activity Learning and Recognition in Aerial Video Surveillance

    Directory of Open Access Journals (Sweden)

    Riad I. Hammoud

    2014-10-01

    Full Text Available We describe two advanced video analysis techniques, including video-indexed by voice annotations (VIVA and multi-media indexing and explorer (MINER. VIVA utilizes analyst call-outs (ACOs in the form of chat messages (voice-to-text to associate labels with video target tracks, to designate spatial-temporal activity boundaries and to augment video tracking in challenging scenarios. Challenging scenarios include low-resolution sensors, moving targets and target trajectories obscured by natural and man-made clutter. MINER includes: (1 a fusion of graphical track and text data using probabilistic methods; (2 an activity pattern learning framework to support querying an index of activities of interest (AOIs and targets of interest (TOIs by movement type and geolocation; and (3 a user interface to support streaming multi-intelligence data processing. We also present an activity pattern learning framework that uses the multi-source associated data as training to index a large archive of full-motion videos (FMV. VIVA and MINER examples are demonstrated for wide aerial/overhead imagery over common data sets affording an improvement in tracking from video data alone, leading to 84% detection with modest misdetection/false alarm results due to the complexity of the scenario. The novel use of ACOs and chat Sensors 2014, 14 19844 messages in video tracking paves the way for user interaction, correction and preparation of situation awareness reports.

  19. Selective activation of M4 muscarinic acetylcholine receptors reverses MK-801-induced behavioral impairments and enhances associative learning in rodents.

    Science.gov (United States)

    Bubser, Michael; Bridges, Thomas M; Dencker, Ditte; Gould, Robert W; Grannan, Michael; Noetzel, Meredith J; Lamsal, Atin; Niswender, Colleen M; Daniels, J Scott; Poslusney, Michael S; Melancon, Bruce J; Tarr, James C; Byers, Frank W; Wess, Jürgen; Duggan, Mark E; Dunlop, John; Wood, Michael W; Brandon, Nicholas J; Wood, Michael R; Lindsley, Craig W; Conn, P Jeffrey; Jones, Carrie K

    2014-10-15

    Positive allosteric modulators (PAMs) of the M4 muscarinic acetylcholine receptor (mAChR) represent a novel approach for the treatment of psychotic symptoms associated with schizophrenia and other neuropsychiatric disorders. We recently reported that the selective M4 PAM VU0152100 produced an antipsychotic drug-like profile in rodents after amphetamine challenge. Previous studies suggest that enhanced cholinergic activity may also improve cognitive function and reverse deficits observed with reduced signaling through the N-methyl-d-aspartate subtype of the glutamate receptor (NMDAR) in the central nervous system. Prior to this study, the M1 mAChR subtype was viewed as the primary candidate for these actions relative to the other mAChR subtypes. Here we describe the discovery of a novel M4 PAM, VU0467154, with enhanced in vitro potency and improved pharmacokinetic properties relative to other M4 PAMs, enabling a more extensive characterization of M4 actions in rodent models. We used VU0467154 to test the hypothesis that selective potentiation of M4 receptor signaling could ameliorate the behavioral, cognitive, and neurochemical impairments induced by the noncompetitive NMDAR antagonist MK-801. VU0467154 produced a robust dose-dependent reversal of MK-801-induced hyperlocomotion and deficits in preclinical models of associative learning and memory functions, including the touchscreen pairwise visual discrimination task in wild-type mice, but failed to reverse these stimulant-induced deficits in M4 KO mice. VU0467154 also enhanced the acquisition of both contextual and cue-mediated fear conditioning when administered alone in wild-type mice. These novel findings suggest that M4 PAMs may provide a strategy for addressing the more complex affective and cognitive disruptions associated with schizophrenia and other neuropsychiatric disorders.

  20. Arts and Learning Research, 1991. The Journal of the Arts and Learning Special Interest Group of the American Educational Research Association (Chicago, Illinois, April 1991).

    Science.gov (United States)

    Stuhr, Patricia L., Ed.

    1991-01-01

    The papers gathered in this volume were presented at the 1991 meeting of the American Educational Research Association. All the papers were presented as part of the Arts and Learning Special Interest Group (SIG) or were cosponsored by the arts SIG. Following an editorial, papers in this volume are: "Four Types of Women's History and How They…

  1. A positive association between active lifestyle and hemispheric lateralization for motor control and learning in older adults.

    Science.gov (United States)

    Wang, Jinsung; D'Amato, Arthur; Bambrough, Jennifer; Swartz, Ann M; Miller, Nora E

    2016-11-01

    Physical activity (PA) is well known to have general health benefits for older adults, but it is unclear whether it can also positively affect brain function involved in motor control and learning. We have previously shown that interlimb transfer of visuomotor adaptation occurs asymmetrically in young adults, while that occurs symmetrically in older adults, which suggests that the lateralized function of each hemisphere during motor tasks is diminished with aging. Here, we investigated the association between the level of PA and hemispheric motor lateralization by comparing the pattern of interlimb transfer following visuomotor adaptation between physically active and inactive older adults. Subjects were divided into two groups based on their PA level (active, inactive). They were further divided into two groups, such that a half of the subjects in each group adapted to a 30° rotation during targeted reaching movements with the left arm first, then with the right arm; and the other half with the right arm first, then with the left arm. Results indicated asymmetrical transfer (from left to right only) in the active subjects, whereas symmetrical transfer (from left to right, and vice versa) was observed in the inactive subjects. These findings suggest that older adults who maintain active lifestyle have a central nervous system that is more intact in terms of its lateralized motor function as compared with those who are inactive. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Equine Assisted Psychotherapy: The Equine Assisted Growth and Learning Association's Model Overview of Equine-Based Modalities

    Science.gov (United States)

    Notgrass, Clayton G.; Pettinelli, J. Douglas

    2015-01-01

    This article describes the Equine Assisted Growth and Learning Association's (EAGALA) experiential model called "Equine Assisted Psychotherapy" (EAP). EAGALA's model is based on the Association for Experiential Education's (AEE) tenets and is focused on the learner's experience with horses. Drawing on the historical use of equines in the…

  3. Learning democracy in a Swedish gamers’ association: Representative democracy as experiential knowledge in a liquid civil society

    Directory of Open Access Journals (Sweden)

    Tobias Harding

    2011-10-01

    Full Text Available To explore the role of civil society organizations in learning democracy this articlecombines the concept of democracy as 'phronesis' with neo-institutional theory, as well as with Hannah Pitkin's concepts of representation. It presents a case study (based on qualitative research of how democracy is learned in SVEROK, a Swedish youth organization focusing on activities such as computer and role-playing games, activities often associated with informal organization. In SVEROK they are organized in an organization sharing many features with established Swedish organizations, including hierarchic formal representative democracy. The norm in SVEROK is a pragmatic organizational knowledge focusing on substantive and formal representation. Organized education plays only a limited role. Learning is typically informal and experience-based. An organization similar to earlier national organizations is createdby self-organized and self-governing associations in government-supported cooperation. The case study supports Theda Skocpol's argument that organizationalstructure is vital to democratic learning.

  4. Grapheme learning and grapheme-color synesthesia: Toward a comprehensive model of grapheme-color association

    Directory of Open Access Journals (Sweden)

    Michiko eAsano

    2013-11-01

    Full Text Available Recent progress in grapheme-color synesthesia research has revealed that certain regularities, as well as individual differences, figure into grapheme-color associations. Although several factors are known to regulate grapheme-color associations, the impact of factors, including their interrelationships, on synesthesia remains unclear. We investigated determinants of synesthetic color for graphemes (characters, letters of Hiragana, a phonetic script in the Japanese language, and the English alphabet. Results revealed that grapheme ordinality was the strongest predictor of synesthetic colors for Hiragana characters, followed by character sound, and visual shape. Ordinality and visual shapes also significantly predicted synesthetic colors for English alphabet letters, however, sounds did not. The relative impact of grapheme properties on grapheme-color associations and the differences between these two writing systems are accounted for by considering the way graphemes are processed in the brain and introduced during an individual's development. A new model is proposed which takes into account the developmental process of grapheme learning. The model provides comprehensive explanation of synesthetic grapheme-color association determination processes, including the differences across writing systems.

  5. Agnostic Active Learning Without Constraints

    OpenAIRE

    Beygelzimer, Alina; Hsu, Daniel; Langford, John; Zhang, Tong

    2010-01-01

    We present and analyze an agnostic active learning algorithm that works without keeping a version space. This is unlike all previous approaches where a restricted set of candidate hypotheses is maintained throughout learning, and only hypotheses from this set are ever returned. By avoiding this version space approach, our algorithm sheds the computational burden and brittleness associated with maintaining version spaces, yet still allows for substantial improvements over supervised learning f...

  6. The relationship between visitor characteristics and learning-associated behaviors in a science museum discovery space

    Science.gov (United States)

    Lozowski Boisvert, Dorothy; Jochums Slez, Brenda

    As informal educational institutions, science museums must do more than entertain and amaze visitors. Museum educators must design exhibits that attract and hold the attention of visitors long enough so that the visitors become engaged with the exhibits and learn from them. In order for museum educators to develop such exhibits, more information is needed about the variables associated with learning in museums. This study contributes to the growing body of knowledge on informal education by examining the relationship between visitor characteristics and attraction, holding power, and visitor engagement.One hundred fifty-four visitors to a science museum discovery space were observed as they interacted freely with the exhibits. Trained volunteers recorded the subjects' movements including the exhibits at which they stopped (attraction), the amount of time spent at each exhibit (holding power), and behaviors indicative of subjects' engagement levels with the exhibits. Data indicated significant differences between age group and the holding power of exhibits. Though not significant statistically, a similar trend was noted between age group and attraction and visitor engagement level. No significant differences were found between gender or social grouping and attraction, holding power, or engagement levels.

  7. Associative learning versus fear habituation as predictors of long-term extinction retention.

    Science.gov (United States)

    Brown, Lily A; LeBeau, Richard T; Chat, Ka Yi; Craske, Michelle G

    2017-06-01

    Violation of unconditioned stimulus (US) expectancy during extinction training may enhance associative learning and result in improved long-term extinction retention compared to within-session habituation. This experiment examines variation in US expectancy (i.e., expectancy violation) as a predictor of long-term extinction retention. It also examines within-session habituation of fear-potentiated startle (electromyography, EMG) and fear of conditioned stimuli (CS) throughout extinction training as predictors of extinction retention. Participants (n = 63) underwent fear conditioning, extinction and retention and provided continuous ratings of US expectancy and EMG, as well as CS fear ratings before and after each phase. Variation in US expectancy throughout extinction and habituation of EMG and fear was entered into a regression as predictors of retention and reinstatement of levels of expectancy and fear. Greater variation in US expectancy throughout extinction training was significantly predictive of enhanced extinction performance measured at retention test, although not after reinstatement test. Slope of EMG and CS fear during extinction did not predict retention of extinction. Within-session habituation of EMG and self-reported fear is not sufficient for long-term retention of extinction learning, and models emphasizing expectation violation may result in enhanced outcomes.

  8. Polymorphisms affecting micro-RNA regulation and associated with the risk of dietary-related cancers: A review from the literature and new evidence for a functional role of rs17281995 (CD86) and rs1051690 (INSR), previously associated with colorectal cancer

    International Nuclear Information System (INIS)

    Landi, Debora; Moreno, Victor; Guino, Elisabeth; Vodicka, Pavel; Pardini, Barbara; Naccarati, Alessio; Canzian, Federico; Barale, Roberto; Gemignani, Federica; Landi, Stefano

    2011-01-01

    In this review, we focus on the genetic variations (single nucleotide polymorphisms, SNPs) known to occur in microRNAs and in their binding sites and the susceptibility to cancers of the gastro-intestinal (GI) tract in humans. Since the sequence complementarity and the thermodynamics of binding play an essential role in the interaction of miRNA with its target mRNA, sequence variations in the miRNA-binding seed regions or in miRNA genes (either within pre-, pri-, or mature miRNA regions) should reinforce, weaken, or disrupt the miRNA–mRNA interaction and affect the expression of mRNA targets. Indirect evidences supporting these hypotheses are reported in the literature, essentially coming from case–control association studies. Several studies have been published on the association between miR-SNPs or SNPs within their binding sites and the risk of oesophageal, gastric, or colorectal cancer. Unfortunately, functional studies are lacking. Besides reviewing the available literature, we present here for the first time two SNPs (rs17281995 in CD86 and rs1051690 in INSR) previously associated with the risk of CRC in a Czech population are also associated with the risk in a Spanish population. Moreover, we show for the first time that both these alleles regulate differentially the amount of a reporter gene (luciferase) in an in vitro assay on HeLa cells. These findings suggest that both these SNPs may have a functional role in regulating the expression of CD-86 and INSR proteins acting at the level of the 3′UTR. More functional studies are needed in order to better understand the role of polymorphic regulatory sequences at the 3′UTR of genes.

  9. Polymorphisms affecting micro-RNA regulation and associated with the risk of dietary-related cancers: A review from the literature and new evidence for a functional role of rs17281995 (CD86) and rs1051690 (INSR), previously associated with colorectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Landi, Debora [Dipartimento di Biologia, University of Pisa, Via Derna, 1, 56126 Pisa (Italy); Moreno, Victor; Guino, Elisabeth [Biostatistics and Bioinformatics Unit, IDIBELL-Catalan Institute of Oncology, Gran Via km 2.7, 08907 L' Hospitalet del Llobregat, Barcelona (Spain); Vodicka, Pavel; Pardini, Barbara; Naccarati, Alessio [Department of Molecular Biology of Cancer, Institute of Experimental Medicine, Academy of Science of Czech Republic, Videnska 1083, 14220 Prague 4 (Czech Republic); Canzian, Federico [Genomic Epidemiology Group, German Cancer Research Center (DKFZ), Heidelberg (Germany); Barale, Roberto; Gemignani, Federica [Dipartimento di Biologia, University of Pisa, Via Derna, 1, 56126 Pisa (Italy); Landi, Stefano, E-mail: slandi@biologia.unipi.it [Dipartimento di Biologia, University of Pisa, Via Derna, 1, 56126 Pisa (Italy)

    2011-12-01

    In this review, we focus on the genetic variations (single nucleotide polymorphisms, SNPs) known to occur in microRNAs and in their binding sites and the susceptibility to cancers of the gastro-intestinal (GI) tract in humans. Since the sequence complementarity and the thermodynamics of binding play an essential role in the interaction of miRNA with its target mRNA, sequence variations in the miRNA-binding seed regions or in miRNA genes (either within pre-, pri-, or mature miRNA regions) should reinforce, weaken, or disrupt the miRNA-mRNA interaction and affect the expression of mRNA targets. Indirect evidences supporting these hypotheses are reported in the literature, essentially coming from case-control association studies. Several studies have been published on the association between miR-SNPs or SNPs within their binding sites and the risk of oesophageal, gastric, or colorectal cancer. Unfortunately, functional studies are lacking. Besides reviewing the available literature, we present here for the first time two SNPs (rs17281995 in CD86 and rs1051690 in INSR) previously associated with the risk of CRC in a Czech population are also associated with the risk in a Spanish population. Moreover, we show for the first time that both these alleles regulate differentially the amount of a reporter gene (luciferase) in an in vitro assay on HeLa cells. These findings suggest that both these SNPs may have a functional role in regulating the expression of CD-86 and INSR proteins acting at the level of the 3 Prime UTR. More functional studies are needed in order to better understand the role of polymorphic regulatory sequences at the 3 Prime UTR of genes.

  10. Retrieval cues that trigger reconsolidation of associative fear memory are not necessarily an exact replica of the original learning experience.

    Science.gov (United States)

    Soeter, Marieke; Kindt, Merel

    2015-01-01

    Disrupting the process of memory reconsolidation may point to a novel therapeutic strategy for the permanent reduction of fear in patients suffering from anxiety disorders. However both in animal and human studies the retrieval cue typically involves a re-exposure to the original fear-conditioned stimulus (CS). A relevant question is whether abstract cues not directly associated with the threat event also trigger reconsolidation, given that anxiety disorders often result from vicarious or unobtrusive learning for which no explicit memory exists. Insofar as the fear memory involves a flexible representation of the original learning experience, we hypothesized that the process of memory reconsolidation may also be triggered by abstract cues. We addressed this hypothesis by using a differential human fear-conditioning procedure in two distinct fear-learning groups. We predicted that if fear learning involves discrimination on basis of perceptual cues within one semantic category (i.e., the perceptual-learning group, n = 15), the subsequent ambiguity of the abstract retrieval cue would not trigger memory reconsolidation. In contrast, if fear learning involves discriminating between two semantic categories (i.e., categorical-learning group, n = 15), an abstract retrieval cue would unequivocally reactivate the fear memory and might subsequently trigger memory reconsolidation. Here we show that memory reconsolidation may indeed be triggered by another cue than the one that was present during the original learning occasion, but this effect depends on the learning history. Evidence for fear memory reconsolidation was inferred from the fear-erasing effect of one pill of propranolol (40 mg) systemically administered upon exposure to the abstract retrieval cue. Our finding that reconsolidation of a specific fear association does not require exposure to the original retrieval cue supports the feasibility of reconsolidation-based interventions for emotional disorders.

  11. Retrieval cues that trigger reconsolidation of associative fear memory are not necessarily an exact replica of the original learning experience

    Directory of Open Access Journals (Sweden)

    Marieke eSoeter

    2015-05-01

    Full Text Available Disrupting the process of memory reconsolidation may point to a novel therapeutic strategy for the permanent reduction of fear in patients suffering from anxiety disorders. However both in animal and human studies the retrieval cue typically involves a re-exposure to the original fear-conditioned stimulus. A relevant question is whether abstract cues not directly associated with the threat event also trigger reconsolidation, given that anxiety disorders often result from vicarious or unobtrusive learning for which no explicit memory exists. Insofar as the fear memory involves a flexible representation of the original learning experience, we hypothesized that the process of memory reconsolidation may also be triggered by abstract cues. We addressed this hypothesis by using a differential human fear-conditioning procedure in two distinct fear-learning groups. We predicted that if fear learning involves discrimination on basis of perceptual cues within one semantic category (i.e., the perceptual-learning group, n = 15, the subsequent ambiguity of the abstract retrieval cue would not trigger memory reconsolidation. In contrast, if fear learning involves discriminating between two semantic categories (i.e., categorical-learning group, n = 15, an abstract retrieval cue would unequivocally reactivate the fear memory and might subsequently trigger memory reconsolidation. Here we show that memory reconsolidation may indeed be triggered by another cue than the one that was present during the original learning occasion, but this effect depends on the learning history. Evidence for fear memory reconsolidation was inferred from the fear-erasing effect of one pill of propranolol (40 mg systemically administered upon exposure to the abstract retrieval cue. Our finding that reconsolidation of a specific fear association does not require exposure to the original retrieval cue supports the feasibility of reconsolidation-based interventions for emotional disorders.

  12. Abdominal wall fibromatosis associated with previous laparoscopic hernia repair.

    Science.gov (United States)

    Brown, S B F; MacDuff, E; O'Dwyer, P J

    2013-10-01

    Two cases of desmoid-type fibromatosis developing after laparoscopic hernia repair are described: one in a young male 3 years after laparoscopic umbilical hernia repair and the other in a young female 1 year after laparoscopic incisional hernia repair. The male patient presented with a slowly enlarging non-tender firm abdominal wall mass; the female patient had similar findings. Excision biopsy in the male and core biopsy in the female were consistent with fibromatosis. The young male patient underwent resection of the fibromatosis, and the female patient has been managed conservatively. These are the first documented cases of fibromatosis developing after laparoscopic hernia surgery. Whilst the safety of hernia meshes has been assessed in animal studies, it may be that more detailed study of intraperitoneal placement of these meshes is required.

  13. Lung cancer in Hodgkin's disease: association with previous radiotherapy

    International Nuclear Information System (INIS)

    List, A.F.; Doll, D.C.; Greco, F.A.

    1985-01-01

    Seven cases of lung cancer were observed in patients with Hodgkin's disease (HD) since 1970. The risk ratio for the development of lung cancer among HD patients was 5.6 times that expected in the general population. The pertinent clinical data from these patients are described and compared to 28 additional patients reported from other institutions. Small-cell lung cancer represented the predominant histologic type of lung cancer encountered in both smoking and nonsmoking patients with HD, accounting for 42% of cases overall and greater than 55% of cases reported in reviews of second malignancies. Tobacco use was noted in only 53% of patients. Twenty-eight (94%) of 30 patients developing metachronous lung cancer received supradiaphragmatic irradiation as primary therapy for HD. Nineteen (68%) of these patients received subsequent chemotherapy salvage. The median age at diagnosis of HD and lung cancer was 39 and 45 years, respectively. The interval between diagnosis of HD and metachronous lung cancer averaged seven years but appeared to vary inversely with age. HD patients treated with supradiaphragmatic irradiation or combined modality therapy may be at increased risk for developing lung cancer. The high frequency of in-field malignancies that the authors observed and the prevalence of small-cell lung cancer in both smoking and nonsmoking patients suggests that chest irradiation may influence the development of metachronous lung cancer in these patients. The finding of a mean latent interval in excess of seven years emphasizes the need for close long-term observation

  14. Associative learning in humans--conditioning of sensory-evoked brain activity.

    Science.gov (United States)

    Skrandies, W; Jedynak, A

    2000-01-01

    A classical conditioning paradigm was employed in two experiments performed on 35 human volunteers. In nine subjects, the presentation of Landolt rings (conditioned stimuli, CS + ) was paired with an electric stimulus (unconditioned stimuli, UCS) applied to the left median nerve. Neutral visual control stimuli were full circles (CS -) that were not paired with the UCS. The skin conductance response (SCR) was determined in a time interval of 5 s after onset of the visual stimuli, and it was measured in the acquisition and test phase. Associative learning was reflected by a SCR occurring selectively with CS +. The same experiment was repeated with another group of 26 adults while electroencephalogram (EEG) was recorded from 30 electrodes. For each subject, mean evoked potentials were computed. In 13 of the subjects, a conditioning paradigm was followed while the other subjects served as the control group (non-contingent stimulation). There were somatosensory and visual brain activity evoked by the stimuli. Conditioned components were identified by computing cross-correlation between evoked somatosensory components and the averaged EEG. In the visual evoked brain activity, three components with mean latencies of 105.4, 183.2, and 360.3 ms were analyzed. Somatosensory stimuli were followed by major components that occurred at mean latencies of 48.8, 132.5, 219.7, 294.8, and 374.2 ms latency after the shock. All components were analyzed in terms of latency, field strength, and topographic characteristics, and were compared between groups and experimental conditions. Both visual and somatosensory brain activity was significantly affected by classical conditioning. Our data illustrate how associative learning affects the topography of brain electrical activity elicited by presentation of conditioned visual stimuli.

  15. Baseline transition sleep and associated sleep episodes are related to the learning ability of rats.

    Science.gov (United States)

    Vescia, S; Mandile, P; Montagnese, P; Romano, F; Cataldo, G; Cotugno, M; Giuditta, A

    1996-12-01

    The EEGs of 18 adult male Wistar rats were recorded during a baseline session lasting 7 h (day 1). The following day, rats were trained for a 2-way active avoidance task in an automated shuttle-box. A retention test was scheduled on the third day. On the basis of the number of avoidances scored during the training and retention sessions, rats were assigned to a fast-learning group (FL; achieving criterion during the training session), a slow-learning group (SL; achieving criterion in the retention test session), and a nonlearning group (NL; failing to achieve criterion). Vigilance states were determined by analyzing EEG data in 5-s epochs and calculating EEG power spectra of consecutive time intervals as short as 1 s. This high-resolution method led to the identification of transition sleep episodes that followed slow-wave sleep (SS) and were followed by waking (TS-->W) or by paradoxical sleep (TS-->PS). Comparison of the baseline sleep variables of the 3 behavioral groups revealed the presence of several significant differences. These observations were confirmed by the results of correlative analyses between baseline sleep variables and number of avoidances scored during the training and retention sessions. The most reliable indices of the capacity to learn the avoidance task were the amounts of SS preceding the TS-->W or the TS-->PS sequence, and the amounts of either component of the latter sequence. These variables displayed markedly higher values in FL rats. In addition, the amount of SS preceding TS-->W and the amount of TS-->(W) were significantly correlated with the number of avoidances scored during the training session. On the other hand, 1' SS-->(PS) and (SS)-->PS episodes were longer in NL rats than in SL or FL rats, respectively; and 2, the duration of SS-->(PS) episodes was inversely correlated with the number of avoidances of the first training period. The data are interpreted to suggest that TS and associated sleep episodes may predict the

  16. Association of learning styles with research self-efficacy: study of short-term research training program for medical students.

    Science.gov (United States)

    Dumbauld, Jill; Black, Michelle; Depp, Colin A; Daly, Rebecca; Curran, Maureen A; Winegarden, Babbi; Jeste, Dilip V

    2014-12-01

    With a growing need for developing future physician scientists, identifying characteristics of medical students who are likely to benefit from research training programs is important. This study assessed if specific learning styles of medical students, participating in federally funded short-term research training programs, were associated with research self-efficacy, a potential predictor of research career success. Seventy-five first-year medical students from 28 medical schools, selected to participate in two competitive NIH-supported summer programs for research training in aging, completed rating scales to evaluate learning styles at baseline, and research self-efficacy before and after training. We examined associations of individual learning styles (visual-verbal, sequential-global, sensing-intuitive, and active-reflective) with students' gender, ranking of medical school, and research self-efficacy. Research self-efficacy improved significantly following the training programs. Students with a verbal learning style reported significantly greater research self-efficacy at baseline, while visual, sequential, and intuitive learners demonstrated significantly greater increases in research self-efficacy from baseline to posttraining. No significant relationships were found between learning styles and students' gender or ranking of their medical school. Assessments of learning styles may provide useful information to guide future training endeavors aimed at developing the next generation of physician-scientists. © 2014 Wiley Periodicals, Inc.

  17. Associative learning in two closely related parasitoid wasps: a neuroecological approach

    NARCIS (Netherlands)

    Bleeker, M.A.K.

    2005-01-01

    Insects are useful model organisms to study learning and memory. Their brains are less complex than vertebrate brains, but the basic mechanisms of learning and memory are similar in both taxa. In this thesis I study learning and subsequent memory formation in two parasitoid wasp species that differ

  18. Online Learning Behaviors for Radiology Interns Based on Association Rules and Clustering Technique

    Science.gov (United States)

    Chen, Hsing-Shun; Liou, Chuen-He

    2014-01-01

    In a hospital, clinical teachers must also care for patients, so there is less time for the teaching of clinical courses, or for discussing clinical cases with interns. However, electronic learning (e-learning) can complement clinical skills education for interns in a blended-learning process. Students discuss and interact with classmates in an…

  19. The association between motivation, affect, and self-regulated learning when solving problems

    NARCIS (Netherlands)

    M.A. Baars (Martine); L. Wijnia (Lisette); G.W.C. Paas (Fred)

    2017-01-01

    textabstractSelf-regulated learning (SRL) skills are essential for learning during school years, particularly in complex problem-solving domains, such as biology and math. Although a lot of studies have focused on the cognitive resources that are needed for learning to solve problems in a

  20. Associations between Chinese EFL Graduate Students' Beliefs and Language Learning Strategies

    Science.gov (United States)

    Tang, Mailing; Tian, Jianrong

    2015-01-01

    This study, using Horwitz's Beliefs about Language Learning Inventory and Oxford's Strategy Inventory for Language Learning, investigated learners' beliefs about language learning and their choice of strategy categories among 546 graduate students in China. The correlation between learners' beliefs and their strategy categories use was examined.…

  1. Improved children's motor learning of the basketball free shooting pattern by associating subjective error estimation and extrinsic feedback.

    Science.gov (United States)

    Silva, Leandro de Carvalho da; Pereira-Monfredini, Carla Ferro; Teixeira, Luis Augusto

    2017-09-01

    This study aimed at assessing the interaction between subjective error estimation and frequency of extrinsic feedback in the learning of the basketball free shooting pattern by children. 10- to 12-year olds were assigned to 1 of 4 groups combining subjective error estimation and relative frequency of extrinsic feedback (33% × 100%). Analysis of performance was based on quality of movement pattern. Analysis showed superior learning of the group combining error estimation and 100% feedback frequency, both groups receiving feedback on 33% of trials achieved intermediate results, and the group combining no requirement of error estimation and 100% feedback frequency had the poorest learning. Our results show the benefit of subjective error estimation in association with high frequency of extrinsic feedback in children's motor learning of a sport motor pattern.

  2. The Association Between Learning Climate and Adverse Obstetrical Outcomes in 16 Nontertiary Obstetrics-Gynecology Departments in the Netherlands.

    Science.gov (United States)

    Smirnova, Alina; Ravelli, Anita C J; Stalmeijer, Renée E; Arah, Onyebuchi A; Heineman, Maas Jan; van der Vleuten, Cees P M; van der Post, Joris A M; Lombarts, Kiki M J M H

    2017-12-01

    To investigate the association between learning climate and adverse perinatal and maternal outcomes in obstetrics-gynecology departments. The authors analyzed 23,629 births and 103 learning climate evaluations from 16 nontertiary obstetrics-gynecology departments in the Netherlands in 2013. Multilevel logistic regressions were used to calculate the odds of adverse perinatal and maternal outcomes, by learning climate score tertile, adjusting for maternal and department characteristics. Adverse perinatal outcomes included fetal or early neonatal mortality, five-minute Apgar score < 7, or neonatal intensive care unit admission for ≥ 24 hours. Adverse maternal outcomes included postpartum hemorrhage and/or transfusion, death, uterine rupture, or third- or fourth-degree perineal laceration. Bias analyses were conducted to quantify the sensitivity of the results to uncontrolled confounding and selection bias. Learning climate scores were significantly associated with increased odds of adverse perinatal outcomes (aOR 2.06, 95% CI 1.14-3.72). Compared with the lowest tertile, departments in the middle tertile had 46% greater odds of adverse perinatal outcomes (aOR 1.46, 95% CI 1.09-1.94); departments in the highest tertile had 69% greater odds (aOR 1.69, 95% CI 1.24-2.30). Learning climate was not associated with adverse maternal outcomes (middle vs. lowest tertile: OR 1.04, 95% CI 0.93-1.16; highest vs. lowest tertile: OR 0.98, 95% CI 0.88-1.10). Learning climate was associated with significantly increased odds of adverse perinatal, but not maternal, outcomes. Research in similar clinical contexts is needed to replicate these findings and explore potential mechanisms behind these associations.

  3. Placental complications after a previous cesarean section

    OpenAIRE

    Milošević Jelena; Lilić Vekoslav; Tasić Marija; Radović-Janošević Dragana; Stefanović Milan; Antić Vladimir

    2009-01-01

    Introduction The incidence of cesarean section has been rising in the past 50 years. With the increased number of cesarean sections, the number of pregnancies with the previous cesarean section rises as well. The aim of this study was to establish the influence of the previous cesarean section on the development of placental complications: placenta previa, placental abruption and placenta accreta, as well as to determine the influence of the number of previous cesarean sections on the complic...

  4. International Association for Cognitive Education and Psychology. European Regional Conference: Cognitive Development and Learning from Kindergarten to University. Program and Abstracts

    OpenAIRE

    Hessels, Marco G.P.

    2012-01-01

    Abstracts and program of the 2012 European Regional Conference "Cognitive development and learning from kindergarten to university" of the International Association for Cognitive Education and Psychology.

  5. Differential-associative processing or example elaboration: Which strategy is best for learning the definitions of related and unrelated concepts?

    Science.gov (United States)

    Hannon, Brenda

    2012-10-01

    Definitions of related concepts (e.g., genotype - phenotype ) are prevalent in introductory classes. Consequently, it is important that educators and students know which strategy(s) work best for learning them. This study showed that a new comparative elaboration strategy, called differential-associative processing, was better for learning definitions of related concepts than was an integrative elaborative strategy, called example elaboration. This outcome occurred even though example elaboration was administered in a naturalistic way (Experiment 1) and students spent more time in the example elaboration condition learning (Experiments 1, 2, 3), and generating pieces of information about the concepts (Experiments 2 and 3). Further, with unrelated concepts ( morpheme-fluid intelligence ), performance was similar regardless if students used differential-associative processing or example elaboration (Experiment 3). Taken as a whole, these results suggest that differential-associative processing is better than example elaboration for learning definitions of related concepts and is as good as example elaboration for learning definitions of unrelated concepts.

  6. Lateralization of Sucrose Responsiveness and Non-associative Learning in Honeybees

    Directory of Open Access Journals (Sweden)

    David Baracchi

    2018-03-01

    Full Text Available Lateralization is a fundamental property of the human brain that affects perceptual, motor, and cognitive processes. It is now acknowledged that left–right laterality is widespread across vertebrates and even some invertebrates such as fruit flies and bees. Honeybees, which learn to associate an odorant (the conditioned stimulus, CS with sucrose solution (the unconditioned stimulus, US, recall this association better when trained using their right antenna than they do when using their left antenna. Correspondingly, olfactory sensilla are more abundant on the right antenna and odor encoding by projection neurons of the right antennal lobe results in better odor differentiation than those of the left one. Thus, lateralization arises from asymmetries both in the peripheral and central olfactory system, responsible for detecting the CS. Here, we focused on the US component and studied if lateralization exists in the gustatory system of Apis mellifera. We investigated whether sucrose sensitivity is lateralized both at the level of the antennae and the fore-tarsi in two independent groups of bees. Sucrose sensitivity was assessed by presenting bees with a series of increasing concentrations of sucrose solution delivered either to the left or the right antenna/tarsus and measuring the proboscis extension response to these stimuli. Bees experienced two series of stimulations, one on the left and the other on the right antenna/tarsus. We found that tarsal responsiveness was similar on both sides and that the order of testing affects sucrose responsiveness. On the contrary, antennal responsiveness to sucrose was higher on the right than on the left side, and this effect was independent of the order of antennal stimulation. Given this asymmetry, we also investigated antennal lateralization of habituation to sucrose. We found that the right antenna was more resistant to habituation, which is consistent with its higher sucrose sensitivity. Our results

  7. Neurobehavioral factors associated with referral for learning problems in a community sample: evidence for an adaptational model for learning disorders.

    Science.gov (United States)

    Waber, Deborah P; Weiler, Michael D; Forbes, Peter W; Bernstein, Jane H; Bellinger, David C; Rappaport, Leonard

    2003-01-01

    We evaluated community general education (CGE; n = 178), community special education (CSE; n = 30) and hospital-referred (HR, n = 145) children (ages 7-6 to 11-11) prospectively over a 2-year period. During this period, 17 CGE children were referred for evaluation (community referred; CR). Prior to referral, CR children performed more poorly than community-nonreferred (CNR) children on cognitive ability, academic achievement, attention problems, and information processing. CR group performance was equivalent to that of CSE and HR groups, but HR children showed poorer academic achievement. Referred children performed more poorly on all measures than nonreferred, whether they met formal diagnostic criteria for a learning disorder or not. Learning disorders may be better conceptualized as a context-dependent problem of functional adaptation than as a disability analogous to physical disabilities, raising questions about the validity of using psychometric test scores as the criterion for identification.

  8. Location and direction specificity in motion direction learning associated with a single-level method of constant stimuli.

    Science.gov (United States)

    Xiong, Ying-Zi; Xie, Xin-Yu; Yu, Cong

    2016-02-01

    Recent studies reported significantly less location specificity in motion direction learning than in previous classical studies. The latter performed training with the method of constant stimuli containing a single level of direction difference. In contrast the former used staircase methods that varied the direction difference trial by trial. We suspect that extensive practice with a single direction difference could allow an observer to use some subtle local cues for direction discrimination. Such local cues may be unavailable at a new stimulus location, leading to higher location specificity. To test this hypothesis, we jittered slightly the directions of a stimulus pair by the same amount while keeping the direction difference constant, so as to disturb the potential local cues. We observed significantly more transfer of learning to untrained locations. The local cue effects may also explain the recent controversies regarding the finding that foveal motion direction learning becomes significantly more transferrable to a new direction with TPE (training-plus-exposure) training. One specific study by Zili Liu and collaborators that challenges this finding also used a single-level direction difference for training. We first replicated their results. But we found that if the directions of the stimulus pair were again jittered while the direction difference was kept constant, motion direction learning transferred significantly more to an orthogonal direction with TPE training. Our results thus demonstrate the importance of using appropriate psychophysical methods in training to reduce local-cue related specificity in perceptual learning. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Testing the Role of Dorsal Premotor Cortex in Auditory-Motor Association Learning Using Transcranical Magnetic Stimulation (TMS.

    Directory of Open Access Journals (Sweden)

    Carlotta Lega

    Full Text Available Interactions between the auditory and the motor systems are critical in music as well as in other domains, such as speech. The premotor cortex, specifically the dorsal premotor cortex (dPMC, seems to play a key role in auditory-motor integration, and in mapping the association between a sound and the movement used to produce it. In the present studies we tested the causal role of the dPMC in learning and applying auditory-motor associations using 1 Hz repetitive Transcranical Magnetic Stimulation (rTMS. In this paradigm, non-musicians learn a set of auditory-motor associations through melody training in two contexts: first when the sound to key-press mapping was in a conventional sequential order (low to high tones mapped onto keys from left to right, and then when it was in a novel scrambled order. Participant's ability to match the four pitches to four computer keys was tested before and after the training. In both experiments, the group that received 1 Hz rTMS over the dPMC showed no significant improvement on the pitch-matching task following training, whereas the control group (who received rTMS to visual cortex did. Moreover, in Experiment 2 where the pitch-key mapping was novel, rTMS over the dPMC also interfered with learning. These findings suggest that rTMS over dPMC disturbs the formation of auditory-motor associations, especially when the association is novel and must be learned rather explicitly. The present results contribute to a better understanding of the role of dPMC in auditory-motor integration, suggesting a critical role of dPMC in learning the link between an action and its associated sound.

  10. KNOWLEDGE TRANSFER AND LEARNING: PROBLEMS OF KNOWLEDGE TRANSFER ASSOCIATED WITH TRYING TO SHORT-CIRCUIT THE LEARNING CYCLE

    Directory of Open Access Journals (Sweden)

    Sue Newell

    2006-11-01

    Full Text Available Knowledge is considered to be a key organizational resource in the 21st century and the knowledge management ‘movement’ has alerted organizations to the fact that they should more strategically exploit their knowledge assets. Companies are thus lured by the suggestion that they can gain competitive advantage by the more astute management of their knowledge base and in particular, by the transfer of knowledge across individuals, groups and organizational units, using IT to accomplish this. In this paper, we reflect on this common view of knowledge transfer. More specifically, we question an implication of this view - essentially the possibility of short-circuiting the learning cycle, so that individuals do not have to rely on their personal or shared experiences to identify better practices, but can learn from the codified lessons of others in IT systems. More importantly, we consider the characteristics of knowledge – that knowledge is distributed, ambiguous and disruptive – that makes its transfer highly problematic. Drawing on case research, we relate this to the learning cycle (Kolb 1984 and thereby identify barriers to knowledge transfer. We conclude by considering ways of overcoming these barriers by emphasizing the importance of social systems alongside technical systems.

  11. Maximising Intercultural Learning in Short Term International Placements: Findings Associated with Orientation Programs, Guided Reflection and Immersion

    Science.gov (United States)

    Campbell, Coral J. L.; Walta, Caroline

    2015-01-01

    Short-term international practicum experience is now a feature of many university education programs in Australia in an attempt to engage students with the growing multi-cultural aspects of Australian life. The stated purposes of such practicum experiences generally highlight intercultural learning, which is associated with the development of…

  12. Are Cardiovascular Risk Factors Associated with Verbal Learning and Memory Impairment in Patients with Schizophrenia? A Cross-Sectional Study

    Directory of Open Access Journals (Sweden)

    Christophe Lancon

    2012-01-01

    Full Text Available Objective. The aim of this study is to assess the relationships of cardiovascular risk factors with verbal learning and memory in patients with schizophrenia. Methods and Design. cross-sectional study. Inclusion Criteria. Diagnosis of schizophrenia according to the DSM-IV-TR criteria. Data Collection. Sociodemographic information, clinical characteristics, anthropometric measurements, blood tests, and episodic memory using the California Verbal Learning Test (CVLT. Analysis. A multivariate analysis using multiple linear regressions was performed to determine variables that are potentially associated with verbal learning and memory. Results. One hundred and sixty-eight outpatients participated in our study. An association was found between the metabolic syndrome (MetS and memory impairment on measures of verbal learning, and short- and long-term memory. Among the different components of MeTS, hypertriglycerides, abdominal obesity, and low HDL cholesterol were the only factors associated with memory impairment. Alcohol dependence or abuse was associated with a higher rate of forgetting. Conclusion. Our findings suggest that MetS and alcohol use may be linked with memory impairment in schizophrenia. These findings provide important insights into the interdependencies of cardiovascular risk factors and cognitive disorders and support novel strategies for treating and preventing cognitive disorders in patients with schizophrenia.

  13. Impact of novel olfactory stimuli at supra and subthreshold concentrations on the perceived sweetness of sucrose after associative learning.

    Science.gov (United States)

    Labbe, David; Martin, Nathalie

    2009-10-01

    The impact of coexposure to a novel olfactory stimulation in combination with sweet taste on the construction of perceptual interaction was studied. The first objective was to explore whether a new flavoring perceived retronasally at a subthreshold concentration could enhance the perceived sweetness after a coexposure with sucrose using an approach encouraging associative learning. After validating the associative learning by showing an increase of the perceived sweetness by the flavoring at a suprathreshold concentration, we showed that the flavoring stimulation did not impact the perceived sweetness when presented at a subthreshold concentration. The second objective was to validate the absence of associative learning when subjects were exposed to the sucrose flavored solution in a context of coexposure akin to sensory profiling training. As expected, we confirmed that coexposure following sensory profiling training did not promote associative learning, probably because this approach encouraged subjects to consider the olfactory and sweet taste combination as a set of distinct qualities. The potential role of neural integration processes in these results was discussed.

  14. Types of Language Disorders in Students Classified as ED: Prevalence and Association with Learning Disabilities and Psychopathology

    Science.gov (United States)

    Benner, Gregory J.; Mattison, Richard E.; Nelson, J. Ron; Ralston, Nicole C.

    2009-01-01

    The purpose of this study was to determine the prevalence of four types of language disorders among public school students (N = 152) classified as Emotional Disturbance (ED). We also examined the association of the types of language disorders experienced by these students with specific learning disabilities and clinical levels of specific types of…

  15. Associations among Attitudes, Perceived Difficulty of Learning Science, Gender, Parents' Occupation and Students' Scientific Competencies

    Science.gov (United States)

    Chi, ShaoHui; Wang, Zuhao; Liu, Xiufeng; Zhu, Lei

    2017-01-01

    This study investigated the associations among students' attitudes towards science, students' perceived difficulty of learning science, gender, parents' occupations and their scientific competencies. A sample of 1591 (720 males and 871 females) ninth-grade students from 29 junior high schools in Shanghai completed a scientific competency test and…

  16. Variation of the gene coding for DARPP-32 (PPP1R1B) and brain connectivity during associative emotional learning

    NARCIS (Netherlands)

    Curcic-Blake, Branislava; Swart, Marte; Ter Horst, Gert J.; Langers, Dave R. M.; Kema, Ido P.; Aleman, Andre

    2012-01-01

    Associative emotional learning, which is important for the social emotional functioning of individuals and is often impaired in psychiatric illnesses, is in part mediated by dopamine and glutamate pathways in the brain. The protein DARPP-32 is involved in the regulation of dopaminergic and

  17. An Empirical Examination of the Association between Multiple Intelligences and Language Learning Self-Efficacy among TEFL University Students

    Science.gov (United States)

    Moafian, Fatemeh; Ebrahimi, Mohammad Reza

    2015-01-01

    The current study investigated the association between multiple intelligences and language learning efficacy expectations among TEFL (Teaching English as a Foreign Language) university students. To fulfill the aim of the study, 108 junior and senior TEFL students were asked to complete the "Multiple Intelligence Developmental Assessment…

  18. Questioning short-term memory and its measurement: Why digit span measures long-term associative learning.

    Science.gov (United States)

    Jones, Gary; Macken, Bill

    2015-11-01

    Traditional accounts of verbal short-term memory explain differences in performance for different types of verbal material by reference to inherent characteristics of the verbal items making up memory sequences. The role of previous experience with sequences of different types is ostensibly controlled for either by deliberate exclusion or by presenting multiple trials constructed from different random permutations. We cast doubt on this general approach in a detailed analysis of the basis for the robust finding that short-term memory for digit sequences is superior to that for other sequences of verbal material. Specifically, we show across four experiments that this advantage is not due to inherent characteristics of digits as verbal items, nor are individual digits within sequences better remembered than other types of individual verbal items. Rather, the advantage for digit sequences stems from the increased frequency, compared to other verbal material, with which digits appear in random sequences in natural language, and furthermore, relatively frequent digit sequences support better short-term serial recall than less frequent ones. We also provide corpus-based computational support for the argument that performance in a short-term memory setting is a function of basic associative learning processes operating on the linguistic experience of the rememberer. The experimental and computational results raise questions not only about the role played by measurement of digit span in cognition generally, but also about the way in which long-term memory processes impact on short-term memory functioning. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  19. Increased entorhinal-prefrontal theta synchronization parallels decreased entorhinal-hippocampal theta synchronization during learning and consolidation of associative memory.

    Directory of Open Access Journals (Sweden)

    Kaori eTakehara-Nishiuchi

    2012-01-01

    Full Text Available Memories are thought to be encoded as a distributed representation in the neocortex. The medial prefrontal cortex (mPFC has been shown to support the expression of memories that initially depend on the hippocampus (HPC, yet the mechanisms by which the HPC and mPFC access the distributed representations in the neocortex are unknown. By measuring phase synchronization of local field potential (LFP oscillations, we found that learning initiated changes in neuronal communication of the HPC and mPFC with the lateral entorhinal cortex (LEC, an area that is connected with many other neocortical regions. LFPs were recorded simultaneously from the three brain regions while rats formed an association between an auditory stimulus (CS and eyelid stimulation (US in a trace eyeblink conditioning paradigm, as well as during retention one month following learning. Over the course of learning, theta oscillations in the LEC and mPFC became strongly synchronized following the presentation of the CS on trials in which rats exhibited a conditioned response (CR, and this strengthened synchronization was also observed during retention one month after learning. In contrast, CS-evoked theta synchronization between the LEC and HPC decreased with learning. Our results suggest that the communication between the LEC and mPFC is strengthened with learning whereas the communication between the LEC and HPC is concomitantly weakened, suggesting that enhanced LEC-mPFC communication may be a key process for theoretically-proposed neocortical reorganization accompanying encoding and consolidation of a memory.

  20. Preoperative screening: value of previous tests.

    Science.gov (United States)

    Macpherson, D S; Snow, R; Lofgren, R P

    1990-12-15

    To determine the frequency of tests done in the year before elective surgery that might substitute for preoperative screening tests and to determine the frequency of test results that change from a normal value to a value likely to alter perioperative management. Retrospective cohort analysis of computerized laboratory data (complete blood count, sodium, potassium, and creatinine levels, prothrombin time, and partial thromboplastin time). Urban tertiary care Veterans Affairs Hospital. Consecutive sample of 1109 patients who had elective surgery in 1988. At admission, 7549 preoperative tests were done, 47% of which duplicated tests performed in the previous year. Of 3096 previous results that were normal as defined by hospital reference range and done closest to the time of but before admission (median interval, 2 months), 13 (0.4%; 95% CI, 0.2% to 0.7%), repeat values were outside a range considered acceptable for surgery. Most of the abnormalities were predictable from the patient's history, and most were not noted in the medical record. Of 461 previous tests that were abnormal, 78 (17%; CI, 13% to 20%) repeat values at admission were outside a range considered acceptable for surgery (P less than 0.001, frequency of clinically important abnormalities of patients with normal previous results with those with abnormal previous results). Physicians evaluating patients preoperatively could safely substitute the previous test results analyzed in this study for preoperative screening tests if the previous tests are normal and no obvious indication for retesting is present.

  1. Perceived and post-traumatic stress are associated with decreased learning, memory, and fluency in HIV-infected women.

    Science.gov (United States)

    Rubin, Leah H; Cook, Judith A; Springer, Gayle; Weber, Kathleen M; Cohen, Mardge H; Martin, Eileen M; Valcour, Victor G; Benning, Lorie; Alden, Christine; Milam, Joel; Anastos, Kathryn; Young, Mary A; Gustafson, Deborah R; Sundermann, Erin E; Maki, Pauline M

    2017-08-28

    Psychological risk factors (PRFs) are associated with impaired learning and memory in HIV-infected (HIV+) women. We determined the dynamic nature of the effects of PRFs and HIV serostatus on learning and memory over time. Multi-center, prospective cohort study METHODS:: Every two years between 2009 and 2013 (3 times), 646 HIV+ and 300 demographically-similar HIV-uninfected (HIV-) women from the Women's Interagency HIV Study completed neuropsychological (NP) testing and questionnaires measuring PRFs (perceived stress, post-traumatic stress disorder (PTSD) symptoms, depressive symptoms). Using mixed-effects regressions, we examined separate and interactive associations between HIV-serostatus and PRFs on performance over time. HIV+ and HIV- women had similar rates of PRFs. Fluency was the only domain where performance over time depended on the combined influence of HIV-serostatus and stress or PTSD (p's stress and PTSD were associated with a greater cognitive decline in performance (p's stress and PTSD. Irrespective of time, performance on learning and memory depended on the combined influence of HIV-serostatus and stress or PTSD (p's ≤ 0.05). In the context of HIV, stress and PTSD were negatively associated with performance. Effects were pronounced on learning among HIV+ women without effective treatment or viral suppression. Regardless of time or HIV-serostatus, all PRFs were associated with lower speed, global NP, and executive function. More than depression, perceived stress and PTSD symptoms are treatment targets to potentially improve fluency, learning, and memory in women living with HIV particularly when HIV treatment is not optimal.

  2. Enhanced Cocaine-Associated Contextual Learning in Female H/Rouen Mice Selectively Bred for Depressive-Like Behaviors: Molecular and Neuronal Correlates.

    Science.gov (United States)

    Rappeneau, Virginie; Morel, Anne-Laure; El Yacoubi, Malika; Vaugeois, Jean-Marie; Denoroy, Luc; Bérod, Anne

    2015-03-02

    Major depression has multiple comorbidities, in particular drug use disorders, which often lead to more severe and difficult-to-treat illnesses. However, the mechanisms linking these comorbidities remain largely unknown. We investigated how a depressive-like phenotype modulates cocaine-related behaviors using a genetic model of depression: the Helpless H/Rouen (H) mouse. We selected the H mouse line for its long immobility duration in the tail suspension test when compared to non-helpless (NH) and intermediate (I) mice. Since numerous studies revealed important sex differences in drug addiction and depression, we conducted behavioral experiments in both sexes. All mice, regardless of phenotype or sex, developed a similar behavioral sensitization after 5 daily cocaine injections (10 mg/kg). Male H and NH mice exhibited similar cocaine-induced conditioned place preference scores that were only slightly higher than in I mice, whereas female H mice strikingly accrued much higher preferences for the cocaine-associated context than those of I and NH mice. Moreover, female H mice acquired cocaine-associated context learning much faster than I and NH mice, a facilitating effect that was associated to a rapid increase in striatal and accumbal brain-derived neurotrophic factor levels (BDNF; up to 35% 24 h after cocaine conditioning). Finally, when re-exposed to the previously cocaine-associated context, female H mice displayed greater Fos activation in the cingulate cortex, nucleus accumbens, and basolateral amygdala. Our data indicate that neurobiological mechanisms such as alterations in associative learning, striato-accumbal BDNF expression, and limbic-cortico-striatal circuit reactivity could mediate enhanced cocaine vulnerability in female depressive-like mice. © The Author 2015. Published by Oxford University Press on behalf of CINP.

  3. Automatic electromagnetic valve for previous vacuum

    International Nuclear Information System (INIS)

    Granados, C. E.; Martin, F.

    1959-01-01

    A valve which permits the maintenance of an installation vacuum when electric current fails is described. It also lets the air in the previous vacuum bomb to prevent the oil ascending in the vacuum tubes. (Author)

  4. Olfactory enrichment and scent cue associative learning in captive birds of prey.

    Science.gov (United States)

    Nelson Slater, Melissa; Hauber, Mark E

    2017-03-01

    As the use of enrichment in zoos has become a standardized husbandry practice, the continued improvement of enrichment programs should be concomitant with empirical validation of those practices. The role of scent as enrichment remains an unexplored avenue for many bird species. We conducted a multi-phase experiment to introduce wrapped food packages and scent cuing to indicate food presence into the exhibits of several birds of prey species at the Bronx Zoo, New York City, to assess if scent can function as enrichment in these species. Our research found support for these birds associating a novel scent cue from a package with the presence of food inside. When tested with sham (empty) packages, these individuals more often and more extensively handled scented versus unscented packages. Overall, these results indicate the ability of some our small sample of individuals to learn olfactory cues and provide support for trials to include olfactory enrichment as a potential part of the daily routine for some birds of prey in zoo settings. © 2017 Wiley Periodicals, Inc.

  5. Transcranial Direct Current Stimulation Facilitates Associative Learning and Alters Functional Connectivity in the Primate Brain.

    Science.gov (United States)

    Krause, Matthew R; Zanos, Theodoros P; Csorba, Bennett A; Pilly, Praveen K; Choe, Jaehoon; Phillips, Matthew E; Datta, Abhishek; Pack, Christopher C

    2017-10-23

    There has been growing interest in transcranial direct current stimulation (tDCS), a non-invasive technique purported to modulate neural activity via weak, externally applied electric fields. Although some promising preliminary data have been reported for applications ranging from stroke rehabilitation to cognitive enhancement, little is known about how tDCS affects the human brain, and some studies have concluded that it may have no effect at all. Here, we describe a macaque model of tDCS that allows us to simultaneously examine the effects of tDCS on brain activity and behavior. We find that applying tDCS to right prefrontal cortex improves monkeys' performance on an associative learning task. While firing rates do not change within the targeted area, tDCS does induce large low-frequency oscillations in the underlying tissue. These oscillations alter functional connectivity, both locally and between distant brain areas, and these long-range changes correlate with tDCS's effects on behavior. Together, these results are consistent with the idea that tDCS leads to widespread changes in brain activity and suggest that it may be a valuable method for cheaply and non-invasively altering functional connectivity in humans. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Associative learning mechanisms underpinning the transition from recreational drug use to addiction.

    Science.gov (United States)

    Hogarth, Lee; Balleine, Bernard W; Corbit, Laura H; Killcross, Simon

    2013-04-01

    Learning theory proposes that drug seeking is a synthesis of multiple controllers. Whereas goal-directed drug seeking is determined by the anticipated incentive value of the drug, habitual drug seeking is elicited by stimuli that have formed a direct association with the response. Moreover, drug-paired stimuli can transfer control over separately trained drug seeking responses by retrieving an expectation of the drug's identity (specific transfer) or incentive value (general transfer). This review covers outcome devaluation and transfer of stimulus-control procedures in humans and animals, which isolate the differential governance of drug seeking by these four controllers following various degrees of contingent and noncontingent drug exposure. The neural mechanisms underpinning these four controllers are also reviewed. These studies suggest that although initial drug seeking is goal-directed, chronic drug exposure confers a progressive loss of control over action selection by specific outcome representations (impaired outcome devaluation and specific transfer), and a concomitant increase in control over action selection by antecedent stimuli (enhanced habit and general transfer). The prefrontal cortex and mediodorsal thalamus may play a role in this drug-induced transition to behavioral autonomy. © 2012 New York Academy of Sciences.

  7. Examining the direct and indirect effects of visual-verbal paired associate learning on Chinese word reading.

    Science.gov (United States)

    Georgiou, George; Liu, Cuina; Xu, Shiyang

    2017-08-01

    Associative learning, traditionally measured with paired associate learning (PAL) tasks, has been found to predict reading ability in several languages. However, it remains unclear whether it also predicts word reading in Chinese, which is known for its ambiguous print-sound correspondences, and whether its effects are direct or indirect through the effects of other reading-related skills such as phonological awareness and rapid naming. Thus, the purpose of this study was to examine the direct and indirect effects of visual-verbal PAL on word reading in an unselected sample of Chinese children followed from the second to the third kindergarten year. A sample of 141 second-year kindergarten children (71 girls and 70 boys; mean age=58.99months, SD=3.17) were followed for a year and were assessed at both times on measures of visual-verbal PAL, rapid naming, and phonological awareness. In the third kindergarten year, they were also assessed on word reading. The results of path analysis showed that visual-verbal PAL exerted a significant direct effect on word reading that was independent of the effects of phonological awareness and rapid naming. However, it also exerted significant indirect effects through phonological awareness. Taken together, these findings suggest that variations in cross-modal associative learning (as measured by visual-verbal PAL) place constraints on the development of word recognition skills irrespective of the characteristics of the orthography children are learning to read. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Impaired associative fear learning in mice with complete loss or haploinsufficiency of AMPA GluR1 receptors

    Directory of Open Access Journals (Sweden)

    Michael Feyder

    2007-12-01

    Full Text Available There is compelling evidence that L-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA glutamate receptors containing the GluR1 subunit contribute to the molecular mechanisms associated with learning. AMPA GluR1 glutamate receptor knockout mice (KO exhibit abnormal hippocampal and amygdala plasticity, and deficits on various assays for cognition including Pavlovian fear conditioning. Here we examined associative fear learning in mice with complete absence (KO or partial loss (heterozygous mutant, HET of GluR1 on multiple fear conditioning paradigms. After multi-trial delay or trace conditioning, KO displayed impaired tone and context fear recall relative to WT, whereas HET were normal. After one-trial delay conditioning, both KO and HET showed impaired tone and context recall. HET and KO showed normal nociceptive sensitivity in the hot plate and tail flick tests. These data demonstrate that the complete absence of GluR1 subunit-containing receptors prevents the formation of associative fear memories, while GluR1 haploinsufficiency is sufficient to impair one-trial fear learning. These findings support growing evidence of a major role for GluR1-containing AMPA receptors in amygdalamediated forms of learning and memory.

  9. Phoneme Awareness, Visual-Verbal Paired-Associate Learning, and Rapid Automatized Naming as Predictors of Individual Differences in Reading Ability

    Science.gov (United States)

    Warmington, Meesha; Hulme, Charles

    2012-01-01

    This study examines the concurrent relationships between phoneme awareness, visual-verbal paired-associate learning, rapid automatized naming (RAN), and reading skills in 7- to 11-year-old children. Path analyses showed that visual-verbal paired-associate learning and RAN, but not phoneme awareness, were unique predictors of word recognition,…

  10. Modafinil combined with cognitive training is associated with improved learning in healthy volunteers--a randomised controlled trial.

    Science.gov (United States)

    Gilleen, J; Michalopoulou, P G; Reichenberg, A; Drake, R; Wykes, T; Lewis, S W; Kapur, S

    2014-04-01

    Improving cognition in people with neuropsychiatric disorders remains a major clinical target. By themselves pharmacological and non-pharmacological approaches have shown only modest effects in improving cognition. In the present study we tested a recently-proposed methodology to combine CT with a 'cognitive-enhancing' drug to improve cognitive test scores and expanded on previous approaches by delivering combination drug and CT, over a long intervention of repeated sessions, and used multiple tasks to reveal the cognitive processes being enhanced. We also aimed to determine whether gains from this combination approach generalised to untrained tests. In this proof of principle randomised-controlled trial thirty-three healthy volunteers were randomised to receive either modafinil or placebo combined with daily cognitive training over two weeks. Volunteers were trained on tasks of new-language learning, working memory and verbal learning following 200 mg modafinil or placebo for ten days. Improvements in trained and untrained tasks were measured. Rate of new-language learning was significantly enhanced with modafinil, and effects were greatest over the first five sessions. Modafinil improved within-day learning rather than between-day retention. No enhancement of gains with modafinil was observed in working memory nor rate of verbal learning. Gains in all tasks were retained post drug-administration, but transfer effects to broad cognitive abilities were not seen. This study shows that combining CT with modafinil specifically elevates learning over early training sessions compared to CT with placebo and provides a proof of principle experimental paradigm for pharmacological enhancement of cognitive remediation. Copyright © 2014 Elsevier B.V. and ECNP. All rights reserved.

  11. Concomitant and previous osteoporotic vertebral fractures.

    Science.gov (United States)

    Lenski, Markus; Büser, Natalie; Scherer, Michael

    2017-04-01

    Background and purpose - Patients with osteoporosis who present with an acute onset of back pain often have multiple fractures on plain radiographs. Differentiation of an acute osteoporotic vertebral fracture (AOVF) from previous fractures is difficult. The aim of this study was to investigate the incidence of concomitant AOVFs and previous OVFs in patients with symptomatic AOVFs, and to identify risk factors for concomitant AOVFs. Patients and methods - This was a prospective epidemiological study based on the Registry of Pathological Osteoporotic Vertebral Fractures (REPAPORA) with 1,005 patients and 2,874 osteoporotic vertebral fractures, which has been running since February 1, 2006. Concomitant fractures are defined as at least 2 acute short-tau inversion recovery (STIR-) positive vertebral fractures that happen concomitantly. A previous fracture is a STIR-negative fracture at the time of initial diagnostics. Logistic regression was used to examine the influence of various variables on the incidence of concomitant fractures. Results - More than 99% of osteoporotic vertebral fractures occurred in the thoracic and lumbar spine. The incidence of concomitant fractures at the time of first patient contact was 26% and that of previous fractures was 60%. The odds ratio (OR) for concomitant fractures decreased with a higher number of previous fractures (OR =0.86; p = 0.03) and higher dual-energy X-ray absorptiometry T-score (OR =0.72; p = 0.003). Interpretation - Concomitant and previous osteoporotic vertebral fractures are common. Risk factors for concomitant fractures are a low T-score and a low number of previous vertebral fractures in cases of osteoporotic vertebral fracture. An MRI scan of the the complete thoracic and lumbar spine with STIR sequence reduces the risk of under-diagnosis and under-treatment.

  12. Genome-Wide Locations of Potential Epimutations Associated with Environmentally Induced Epigenetic Transgenerational Inheritance of Disease Using a Sequential Machine Learning Prediction Approach.

    Science.gov (United States)

    Haque, M Muksitul; Holder, Lawrence B; Skinner, Michael K

    2015-01-01

    Environmentally induced epigenetic transgenerational inheritance of disease and phenotypic variation involves germline transmitted epimutations. The primary epimutations identified involve altered differential DNA methylation regions (DMRs). Different environmental toxicants have been shown to promote exposure (i.e., toxicant) specific signatures of germline epimutations. Analysis of genomic features associated with these epimutations identified low-density CpG regions (machine learning computational approach to predict all potential epimutations in the genome. A number of previously identified sperm epimutations were used as training sets. A novel machine learning approach using a sequential combination of Active Learning and Imbalance Class Learner analysis was developed. The transgenerational sperm epimutation analysis identified approximately 50K individual sites with a 1 kb mean size and 3,233 regions that had a minimum of three adjacent sites with a mean size of 3.5 kb. A select number of the most relevant genomic features were identified with the low density CpG deserts being a critical genomic feature of the features selected. A similar independent analysis with transgenerational somatic cell epimutation training sets identified a smaller number of 1,503 regions of genome-wide predicted sites and differences in genomic feature contributions. The predicted genome-wide germline (sperm) epimutations were found to be distinct from the predicted somatic cell epimutations. Validation of the genome-wide germline predicted sites used two recently identified transgenerational sperm epimutation signature sets from the pesticides dichlorodiphenyltrichloroethane (DDT) and methoxychlor (MXC) exposure lineage F3 generation. Analysis of this positive validation data set showed a 100% prediction accuracy for all the DDT-MXC sperm epimutations. Observations further elucidate the genomic features associated with transgenerational germline epimutations and identify a genome

  13. Chronically Increased G[subscript s][alpha] Signaling Disrupts Associative and Spatial Learning

    Science.gov (United States)

    Bourtchouladze, Rusiko; Patterson, Susan L.; Kelly, Michele P.; Kreibich, Arati; Kandel, Eric R.; Abel, Ted

    2006-01-01

    The cAMP/PKA pathway plays a critical role in learning and memory systems in animals ranging from mice to "Drosophila" to "Aplysia." Studies of olfactory learning in "Drosophila" suggest that altered expression of either positive or negative regulators of the cAMP/PKA signaling pathway beyond a certain optimum range may be deleterious. Here we…

  14. A computational model associating learning process, word attributes, and age of acquisition.

    Science.gov (United States)

    Hidaka, Shohei

    2013-01-01

    We propose a new model-based approach linking word learning to the age of acquisition (AoA) of words; a new computational tool for understanding the relationships among word learning processes, psychological attributes, and word AoAs as measures of vocabulary growth. The computational model developed describes the distinct statistical relationships between three theoretical factors underpinning word learning and AoA distributions. Simply put, this model formulates how different learning processes, characterized by change in learning rate over time and/or by the number of exposures required to acquire a word, likely result in different AoA distributions depending on word type. We tested the model in three respects. The first analysis showed that the proposed model accounts for empirical AoA distributions better than a standard alternative. The second analysis demonstrated that the estimated learning parameters well predicted the psychological attributes, such as frequency and imageability, of words. The third analysis illustrated that the developmental trend predicted by our estimated learning parameters was consistent with relevant findings in the developmental literature on word learning in children. We further discuss the theoretical implications of our model-based approach.

  15. Metacognitive Monkeys or Associative Animals? Simple Reinforcement Learning Explains Uncertainty in Nonhuman Animals

    Science.gov (United States)

    Le Pelley, M. E.

    2012-01-01

    Monkeys will selectively and adaptively learn to avoid the most difficult trials of a perceptual discrimination learning task. Couchman, Coutinho, Beran, and Smith (2010) have recently demonstrated that this pattern of responding does not depend on animals receiving trial-by-trial feedback for their responses; it also obtains if experience of the…

  16. Associations of Subjective Immersion, Immersion Subfactors, and Learning Outcomes in the Revised Game Engagement Model

    Science.gov (United States)

    Barclay, Paul A.; Bowers, Clint

    2018-01-01

    Serious Educational Video Games (SEGs) play a large role in education for both children and adults. However, the budget for SEGs is typically lower than traditional entertainment video games, bringing with it the need to optimize the learning experience. This article looks at the role game immersion plays in improving learning outcomes, using the…

  17. Psychological and Organizational Variables Associated with Workplace Learning in Small and Medium Manufacturing Businesses in Korea

    Science.gov (United States)

    Moon, Se-Yeon; Na, Seung-Il

    2009-01-01

    The purpose of this study was to determine the relationship between workplace learning and psychological variables, such as learning competency, motivation, curiosity, self-esteem and locus of control, and organizational variables, such as centralization of power, formality, merit system and communication. The studied population consisted entirely…

  18. Indicators of early and late processing reveal the importance of within-trial-time for theories of associative learning.

    Science.gov (United States)

    Lachnit, Harald; Thorwart, Anna; Schultheis, Holger; Lotz, Anja; Koenig, Stephan; Uengoer, Metin

    2013-01-01

    In four human learning experiments (Pavlovian skin conductance, causal learning, speeded classification task), we evaluated several associative learning theories that assume either an elemental (modified unique cue model and Harris' model) or a configural (Pearce's configural theory and an extension of it) form of stimulus processing. The experiments used two modified patterning problems (A/B/C+, AB/BC/AC+ vs. ABC-; A+, BC+ vs. ABC-). Pearce's configural theory successfully predicted all of our data reflecting early stimulus processing, while the predictions of the elemental theories were in accord with all of our data reflecting later stages of stimulus processing. Our results suggest that the form of stimulus representation depends on the amount of time available for stimulus processing. Our findings highlight the necessity to investigate stimulus processing during conditioning on a finer time scale than usually done in contemporary research.

  19. Uterine rupture without previous caesarean delivery

    DEFF Research Database (Denmark)

    Thisted, Dorthe L. A.; H. Mortensen, Laust; Krebs, Lone

    2015-01-01

    OBJECTIVE: To determine incidence and patient characteristics of women with uterine rupture during singleton births at term without a previous caesarean delivery. STUDY DESIGN: Population based cohort study. Women with term singleton birth, no record of previous caesarean delivery and planned...... vaginal delivery (n=611,803) were identified in the Danish Medical Birth Registry (1997-2008). Medical records from women recorded with uterine rupture during labour were reviewed to ascertain events of complete uterine rupture. Relative Risk (RR) and adjusted Relative Risk Ratio (aRR) of complete uterine...... rupture with 95% confidence intervals (95% CI) were ascertained according to characteristics of the women and of the delivery. RESULTS: We identified 20 cases with complete uterine rupture. The incidence of complete uterine rupture among women without previous caesarean delivery was about 3...

  20. Non-linguistic learning and aphasia: Evidence from a paired associate and feedback-based task

    Science.gov (United States)

    Vallila-Rohter, Sofia; Kiran, Swathi

    2013-01-01

    Though aphasia is primarily characterized by impairments in the comprehension and/or expression of language, research has shown that patients with aphasia also show deficits in cognitive-linguistic domains such as attention, executive function, concept knowledge and memory (Helm-Estabrooks, 2002 for review). Research in aphasia suggests that cognitive impairments can impact the online construction of language, new verbal learning, and transactional success (Freedman & Martin, 2001; Hula & McNeil, 2008; Ramsberger, 2005). In our research, we extend this hypothesis to suggest that general cognitive deficits influence progress with therapy. The aim of our study is to explore learning, a cognitive process that is integral to relearning language, yet underexplored in the field of aphasia rehabilitation. We examine non-linguistic category learning in patients with aphasia (n=19) and in healthy controls (n=12), comparing feedback and non-feedback based instruction. Participants complete two computer-based learning tasks that require them to categorize novel animals based on the percentage of features shared with one of two prototypes. As hypothesized, healthy controls showed successful category learning following both methods of instruction. In contrast, only 60% of our patient population demonstrated successful non-linguistic category learning. Patient performance was not predictable by standardized measures of cognitive ability. Results suggest that general learning is affected in aphasia and is a unique, important factor to consider in the field of aphasia rehabilitation. PMID:23127795

  1. Relative prediction error and protection from attentional blink in human associative learning.

    Science.gov (United States)

    Glautier, Steven; Shih, Shui-L

    2015-01-01

    The relationship between predictive learning and attentional processing was investigated in two experiments. During a learning procedure participants viewed rapid serial visual presentation (RSVP) of stimuli in the context of a choice-reaction-time (CRT) task. Salient stimuli in the RSVP streams were either predictive or non-predictive for the outcome of the CRT task. Following this procedure we measured attentional blink (AB) to the predictive and non-predictive stimuli. In Experiment 1, despite the use of a large sample and checks demonstrating the validity of the learning procedure and the AB measure, we did not observe reduced AB for predictive stimuli. In contrast, in Experiment 2,