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Sample records for eyeblink conditioning task

  1. Classical eyeblink conditioning in Parkinson's disease.

    Science.gov (United States)

    Daum, I; Schugens, M M; Breitenstein, C; Topka, H; Spieker, S

    1996-11-01

    Patients with Parkinson's disease (PD) show impairments of a range of motor learning tasks, including tracking or serial reaction time task learning. Our study investigated whether such deficits would also be seen on a simple type of motor learning, classic conditioning of the eyeblink response. Medicated and unmediated patients with PD showed intact unconditioned eyeblink responses and significant learning across acquisition; the learning rates did not differ from those of healthy control subjects. The overall frequency of conditioned responses was significantly higher in the medicated patients with PD relative to control subjects, and there was also some evidence of facilitation in the unmedicated patients with PD. Conditioning of electrodermal and electrocortical responses was comparable in all groups. The findings are discussed in terms of enhanced excitability of brainstem pathways in PD and of the involvement of different neuronal circuits in different types of motor learning.

  2. Eyeblink classical conditioning in the preweanling lamb.

    Science.gov (United States)

    Johnson, Timothy B; Stanton, Mark E; Goodlett, Charles R; Cudd, Timothy A

    2008-06-01

    Classical conditioning of eyeblink responses has been one of the most important models for studying the neurobiology of learning, with many comparative, ontogenetic, and clinical applications. The current study reports the development of procedures to conduct eyeblink conditioning in preweanling lambs and demonstrates successful conditioning using these procedures. These methods will permit application of eyeblink conditioning procedures in the analysis of functional correlates of cerebellar damage in a sheep model of fetal alcohol spectrum disorders, which has significant advantages over more common laboratory rodent models. Because sheep have been widely used for studies of pathogenesis and mechanisms of injury with many different prenatal or perinatal physiological insults, eyeblink conditioning can provide a well-studied method to assess postnatal behavioral outcomes, which heretofore have not typically been pursued with ovine models of developmental insults.

  3. Accelerated trace eyeblink conditioning after cortisol IV-infusion.

    Science.gov (United States)

    Kuehl, Linn K; Lass-Hennemann, Johanna; Richter, Steffen; Blumenthal, Terry D; Oitzl, Melly; Schachinger, Hartmut

    2010-11-01

    Impairing effects of cortisol on learning performance have been shown in human trace eyeblink conditioning. As the effect is observed from 30 min to hours after administration, a genomic action of cortisol is assumed. Here we report rapid cortisol effects that were observed during the first 10 min after cortisol administration in humans. Young healthy males (n=24) received the cortisol synthesis inhibitor metyrapone (1.5 g per os) to avoid interference of the endogenous pulsatile secretion of cortisol. Next, 2mg cortisol or placebo was infused intravenously, immediately before the trace conditioning task. The probability of the conditioned eyeblink responses was assessed electromyographically during the trace eyeblink conditioning task (unconditioned stimulus: corneal air puff, 10 psi, 50 ms; conditioned stimulus: binaural pure tone, 7 dB, 1000 Hz, 400 ms; empty interval between CS and US: 550 ms). Cortisol resulted in a faster increase of conditioning (p=.02), reaching a comparable level to placebo later on. This result extends the well-known effects of stress on the quality and amount of learning by showing that cortisol also affects the speed of learning. We propose that cortisol accelerates trace eyeblink conditioning via a fast, non-genomic mechanism. This fast action of cortisol is part of the adaptive strategy during the early stress response.

  4. Cerebellar Secretin Modulates Eyeblink Classical Conditioning

    Science.gov (United States)

    Fuchs, Jason R.; Robinson, Gain M.; Dean, Aaron M.; Schoenberg, Heidi E.; Williams, Michael R.; Morielli, Anthony D.; Green, John T.

    2014-01-01

    We have previously shown that intracerebellar infusion of the neuropeptide secretin enhances the acquisition phase of eyeblink conditioning (EBC). Here, we sought to test whether endogenous secretin also regulates EBC and to test whether the effect of exogenous and endogenous secretin is specific to acquisition. In Experiment 1, rats received…

  5. Neural Circuitry and Plasticity Mechanisms Underlying Delay Eyeblink Conditioning

    Science.gov (United States)

    Freeman, John H.; Steinmetz, Adam B.

    2011-01-01

    Pavlovian eyeblink conditioning has been used extensively as a model system for examining the neural mechanisms underlying associative learning. Delay eyeblink conditioning depends on the intermediate cerebellum ipsilateral to the conditioned eye. Evidence favors a two-site plasticity model within the cerebellum with long-term depression of…

  6. Cerebellar cortical inhibition and classical eyeblink conditioning.

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    Bao, Shaowen; Chen, Lu; Kim, Jeansok J; Thompson, Richard F

    2002-02-01

    The cerebellum is considered a brain structure in which memories for learned motor responses (e.g., conditioned eyeblink responses) are stored. Within the cerebellum, however, the relative importance of the cortex and the deep nuclei in motor learning/memory is not entirely clear. In this study, we show that the cerebellar cortex exerts both basal and stimulus-activated inhibition to the deep nuclei. Sequential application of a gamma-aminobutyric acid type A receptor (GABA(A)R) agonist and a noncompetitive GABA(A)R antagonist allows selective blockade of stimulus-activated inhibition. By using the same sequential agonist and antagonist methods in behaving animals, we demonstrate that the conditioned response (CR) expression and timing are completely dissociable and involve different inhibitory inputs; although the basal inhibition modulates CR expression, the conditioned stimulus-activated inhibition is required for the proper timing of the CR. In addition, complete blockade of cerebellar deep nuclear GABA(A)Rs prevents CR acquisition. Together, these results suggest that different aspects of the memories for eyeblink CRs are encoded in the cerebellar cortex and the cerebellar deep nuclei.

  7. Eyeblink classical conditioning differentiates normal aging from Alzheimer's disease.

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    Woodruff-Pak, D S

    2001-01-01

    Eyeblink classical conditioning is a useful paradigm for the study of the neurobiology of learning, memory, and aging, which also has application in the differential diagnosis of neurodegenerative diseases expressed in advancing age. Converging evidence from studies of eyeblink conditioning in neurological patients and brain imaging in normal adults document parallels in the neural substrates of this form of associative learning in humans and non-human mammals. Age differences in the short-delay procedure (400 ms CS-US interval) appear in middle age in humans and may be caused at least in part by cerebellar cortical changes such as loss of Purkinje cells. Whereas the hippocampus is not essential for conditioning in the delay procedure, disruption of hippocampal cholinergic neurotransmission impairs acquisition and slows the rate of learning. Alzheimer's disease (AD) profoundly disrupts the hippocampaL cholinergic system, and patients with AD consistently perform poorly in eyeblink conditioning. We hypothesize that disruption of hippocampal cholinergic pathways in AD in addition to age-associated Purkinje cell loss results in severely impaired eyeblink conditioning. The earliest pathology in AD occurs in entorhinal cortical input to hippocampus, and eyeblink conditioning may detect this early disruption before declarative learning and memory circuits become impaired. A case study is presented in which eyeblink conditioning detected impending dementia six years before changes on other screening tests indicated impairment. Because eyeblink conditioning is simple, non-threatening, and non-invasive, it may become a useful addition to test batteries designed to differentiate normal aging from mild cognitive impairment that progresses to AD and AD from other types of dementia.

  8. The involvement of the human cerebellum in eyeblink conditioning.

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    Gerwig, M; Kolb, F P; Timmann, D

    2007-01-01

    Besides its known importance for motor coordination, the cerebellum plays a major role in associative learning. The form of cerebellum-dependent associative learning, which has been examined in greatest detail, is classical conditioning of eyeblink responses. The much advanced knowledge of anatomical correlates, as well as cellular and molecular mechanisms involved in eyeblink conditioning in animal models are of particular importance because there is general acceptance that findings in humans parallel the animal data. The aim of the present review is to give an update of findings in humans. Emphasis is put on human lesion studies, which take advantage of the advances of high-resolution structural magnetic resonance imaging (MRI). In addition, findings of functional brain imaging in healthy human subjects are reviewed. The former helped to localize areas involved in eyeblink conditioning within the cerebellum, the latter was in particular helpful in delineating extracerebellar neural substrates, which may contribute to eyeblink conditioning. Human lesion studies support the importance of cortical areas of the ipsilateral superior cerebellum both in the acquisition and timing of conditioned eyeblink responses (CR). Furthermore, the ipsilateral cerebellar cortex seems to be also important in extinction of CRs. Cortical areas, which are important for CR acquisition, overlap with areas related to the control of the unconditioned eyeblink response. Likewise, cortical lesions are followed by increased amplitudes of unconditioned eyeblinks. These findings are in good accordance with the animal literature. Knowledge about contributions of the cerebellar nuclei in humans, however, is sparse. Due to methodological limitations both of human lesion and functional MRI studies, at present no clear conclusions can be drawn on the relative contributions of the cerebellar cortex and nuclei.

  9. γIsoform-Selective Changes in PKC Immunoreactivity after Trace Eyeblink Conditioning in the Rabbit Hippocampus

    NARCIS (Netherlands)

    Zee, E.A. van der; Kronforst-Collins, M.A.; Maizels, E.T.; Hunzicker-Dunn, M.; Disterhoft, J.F.

    1997-01-01

    An immunocytochemical examination of the rabbit hippocampus was done to determine which of the Ca2+-dependent protein kinase C (PKC) isoforms (PKCα, -βI, -βII, or -γ) are involved in associative learning. The hippocampally dependent trace eyeblink conditioning task was used for behavioral training,

  10. Pretrial Functional Connectivity Differentiates Behavioral Outcomes during Trace Eyeblink Conditioning in the Rabbit

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    Schroeder, Matthew P.; Weiss, Craig; Procissi, Daniel; Wang, Lei; Disterhoft, John F.

    2016-01-01

    Fluctuations in neural activity can produce states that facilitate and accelerate task-related performance. Acquisition of trace eyeblink conditioning (tEBC) in the rabbit is enhanced when trials are contingent on optimal pretrial activity in the hippocampus. Other regions which are essential for whisker-signaled tEBC, such as the cerebellar…

  11. Perirhinal and Postrhinal, but Not Lateral Entorhinal, Cortices Are Essential for Acquisition of Trace Eyeblink Conditioning

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    Suter, Eugenie E.; Weiss, Craig; Disterhoft, John F.

    2013-01-01

    The acquisition of temporal associative tasks such as trace eyeblink conditioning is hippocampus-dependent, while consolidated performance is not. The parahippocampal region mediates much of the input and output of the hippocampus, and perirhinal (PER) and entorhinal (EC) cortices support persistent spiking, a possible mediator of temporal…

  12. Central Cannabinoid Receptors Modulate Acquisition of Eyeblink Conditioning

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    Steinmetz, Adam B.; Freeman, John H.

    2010-01-01

    Delay eyeblink conditioning is established by paired presentations of a conditioned stimulus (CS) such as a tone or light, and an unconditioned stimulus (US) that elicits the blink reflex. Conditioned stimulus information is projected from the basilar pontine nuclei to the cerebellar interpositus nucleus and cortex. The cerebellar cortex,…

  13. Eyeblink Conditioning: A Non-Invasive Biomarker for Neurodevelopmental Disorders

    Science.gov (United States)

    Reeb-Sutherland, Bethany C.; Fox, Nathan A.

    2015-01-01

    Eyeblink conditioning (EBC) is a classical conditioning paradigm typically used to study the underlying neural processes of learning and memory. EBC has a well-defined neural circuitry, is non-invasive, and can be employed in human infants shortly after birth making it an ideal tool to use in both developing and special populations. In addition,…

  14. Normal eyeblink classical conditioning in patients with fixed dystonia

    NARCIS (Netherlands)

    Janssen, S.; Veugen, L.C.; Hoffland, B.S.; Kassavetis, P.; Rooijen, D.E. van; Stegeman, D.F.; Edwards, Mark J.; Hilten, J.J. van; Warrenburg, B.P.C. van de

    2014-01-01

    Fixed dystonia without evidence of basal ganglia lesions or neurodegeneration typically affects young women following minor peripheral trauma. We use eyeblink classical conditioning (EBCC) to study whether cerebellar functioning is abnormal in patients with fixed dystonia, since this is part of the

  15. I Think, Therefore Eyeblink: The Importance of Contingency Awareness in Conditioning.

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    Weidemann, Gabrielle; Satkunarajah, Michelle; Lovibond, Peter F

    2016-04-01

    Can conditioning occur without conscious awareness of the contingency between the stimuli? We trained participants on two separate reaction time tasks that ensured attention to the experimental stimuli. The tasks were then interleaved to create a differential Pavlovian contingency between visual stimuli from one task and an airpuff stimulus from the other. Many participants were unaware of the contingency and failed to show differential eyeblink conditioning, despite attending to a salient stimulus that was contingently and contiguously related to the airpuff stimulus over many trials. Manipulation of awareness by verbal instruction dramatically increased awareness and differential eyeblink responding. These findings cast doubt on dual-system theories, which propose an automatic associative system independent of cognition, and provide strong evidence that cognitive processes associated with awareness play a causal role in learning.

  16. Trace eyeblink conditioning is impaired in α7 but not in β2 nicotinic acetylcholine receptor knock-out mice

    Directory of Open Access Journals (Sweden)

    Kevin L Brown

    2010-10-01

    Full Text Available Nicotinic acetylcholine receptors (nAChRs are essentially involved in learning and memory. A neurobiologically and behaviorally well-characterized measure of learning and memory, eyeblink classical conditioning, is sensitive to disruptions in acetylcholine neurotransmission. The two most common forms of eyeblink classical conditioning – the delay and trace paradigms - differentially engage forebrain areas densely-populated with nAChRs. The present study used genetically modified mice to investigate the effects of selective nAChR subunit deletion on delay and trace eyeblink classical conditioning. α7 and β2 nAChR subunit knockout (KO mice and their wild-type littermates were trained for 10 daily sessions in a 500 ms delay or 500 ms trace eyeblink conditioning task, matched for the interstimulus interval (ISI between conditioned stimulus (CS and unconditioned stimulus (US onset. Impairments in conditioned responding were found in α7 KO mice trained in trace – but not delay – eyeblink conditioning. Relative to littermate controls, β2 KO mice were unimpaired in the trace task but displayed higher levels of conditioned responding in delay eyeblink conditioning. Elevated conditioned response levels in delay-conditioned β2 KOs corresponded to elevated levels of alpha responding in this group. These findings suggest that α7 nAChRs play a role in normal acquisition of 500 ms trace eyeblink classical conditioning in mice. The prominent distribution of α7 nAChRs in the hippocampus and other forebrain regions may account for these genotype-specific acquisition effects in this hippocampus-dependent trace paradigm.

  17. Cerebellum lesion impairs eyeblink-like classical conditioning in goldfish.

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    Gómez, A; Durán, E; Salas, C; Rodríguez, F

    2010-03-10

    The cerebellum of mammals is an essential component of the neural circuitry underlying classical conditioning of eyeblink and other discrete responses. Although the neuroanatomical organization of the cerebellum is notably well conserved in vertebrates, little is actually known about the cerebellar learning functions in nonmammal vertebrate groups. In this work we studied whether the cerebellum of teleost fish plays a critical role in the classical conditioning of a motor response. In Experiment 1, we classically conditioned goldfish in a procedure analogous to the eyeblink conditioning paradigm commonly used in mammals. Goldfish were able to learn to express an eyeblink-like conditioned response to a predictive light (conditioned stimulus) that was paired with a mild electric shock (unconditioned stimulus). The application of unpaired and extinction control procedures demonstrated that also in teleosts the learning of this motor response depends on associative rules. In Experiment 2 we studied whether classical conditioning of this response is critically dependent on the cerebellum and independent of telencephalic structures as occurs in mammals. Cerebellum lesion prevented the acquisition of the eyeblink-like conditioned response whereas telencephalon ablation did not impair the learning of this response. No deficit was observed following lesions in the performance of the unconditioned response or in the percentage of spontaneous responses. These results suggest that cerebellum ablation in goldfish affects a critical component of the circuitry necessary for the acquisition of the conditioned response but does not interfere with the ability of the animal to perform the response itself. The striking similarity in the role of cerebellum in classical conditioning of a motor response between teleost fish and mammals suggests that this learning function of the cerebellum could be a primitive feature of the vertebrate brain that has been conserved through evolution.

  18. Short-term, high-dose administration of corticosterone by injection facilitates trace eyeblink conditioning in young male rats.

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    Wentworth-Eidsaune, Christine L; Hennessy, Michael B; Claflin, Dragana I

    2016-02-01

    Glucocorticoids released as part of the physiological response to stress are known to affect cognitive function, presumably via effects on the hippocampus. Trace classical eyeblink conditioning is an associative learning task which depends on the hippocampus and has been used to examine the development of learning processes in young mammals. Previously, we demonstrated deficits in trace eyeblink conditioning associated with postnatal administration of the glucocorticoid corticosterone by creating a sustained elevation with methods such as subcutaneous timed-release pellets and osmotic mini-pumps which were active over several days. In the present study, we examined the effects of an oscillating pattern of corticosterone elevation on subsequent trace eyeblink conditioning. Twice daily corticosterone injections (high, low, or vehicle) were administered over a 3-day period, starting at postnatal day 15. Then, on postnatal day 28, animals underwent trace classical eyeblink conditioning to examine the possible influence of earlier corticosterone elevations on the development of learning and memory. Eyeblink conditioning was affected by corticosterone treatments, but only for males, and only very early in acquisition; Males receiving the high dose of corticosterone exhibited facilitation of learning relative to controls. These data demonstrate that oscillating corticosterone elevations produce opposite effects on this associative learning task than do sustained elevations.

  19. Shortened Conditioned Eyeblink Response Latency in Male but not Female Wistar-Kyoto Hyperactive Rats

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    Thanellou, Alexandra; Schachinger, Kira M.; Green, John T.

    2014-01-01

    Reductions in the volume of the cerebellum and impairments in cerebellar-dependent eyeblink conditioning have been observed in attention-deficit/hyperactivity disorder (ADHD). Recently, it was reported that subjects with ADHD as well as male spontaneously hypertensive rats (SHR), a strain that is frequently employed as an animal model in the study of ADHD, exhibit a parallel pattern of timing deficits in eyeblink conditioning. One criticism that has been posed regarding the validity of the SHR strain as an animal model for the study of ADHD is that SHRs are not only hyperactive but also hypertensive. It is conceivable that many of the behavioral characteristics seen in SHRs that seem to parallel the behavioral symptoms of ADHD are not solely due to hyperactivity but instead are the net outcome of the interaction between hyperactivity and hypertension. We used Wistar-Kyoto Hyperactive (WKHA) and Wistar-Kyoto Hypertensive (WKHT) rats (males and females), strains generated from recombinant inbreeding of SHRs and their progenitor strain, Wistar-Kyoto (WKY) rats, to compare eyeblink conditioning in strains that are exclusively hyperactive or hypertensive. We used a long-delay eyeblink conditioning task in which a tone conditioned stimulus was paired with a periorbital stimulation unconditioned stimulus (750-ms delay paradigm). Our results showed that WKHA and WKHT rats exhibited similar rates of conditioned response (CR) acquisition. However, WKHA males displayed shortened CR latencies (early onset and peak latency) in comparison to WKHT males. In contrast, female WKHAs and WKHTs did not differ. In subsequent extinction training, WKHA rats extinguished at similar rates in comparison to WKHT rats. The current results support the hypothesis of a relationship between cerebellar abnormalities and ADHD in an animal model of ADHD-like symptoms that does not also exhibit hypertension, and suggest that cerebellar-related timing deficits are specific to males. PMID:19485572

  20. Choline supplementation mitigates trace, but not delay, eyeblink conditioning deficits in rats exposed to alcohol during development.

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    Thomas, Jennifer D; Tran, Tuan D

    2012-03-01

    Children exposed to alcohol prenatally suffer from a range of physical, neuropathological, and behavioral alterations, referred to as fetal alcohol spectrum disorders (FASD). Both the cerebellum and hippocampus are affected by alcohol exposure during development, which may contribute to behavioral and cognitive deficits observed in children with FASD. Despite the known neuropathology associated with prenatal alcohol exposure, many pregnant women continue to drink (heavy drinkers, in particular), creating a need to identify effective treatments for their children who are adversely affected by alcohol. We previously reported that choline supplementation can mitigate alcohol's effects on cognitive development, specifically on tasks which depend on the functional integrity of the hippocampus. The present study examined whether choline supplementation could differentially mitigate alcohol's effects on trace eyeblink classical conditioning (ECC, a hippocampal-dependent task) and delay ECC (a cerebellar-dependent task). Long-Evans rats were exposed to 5.25 g/kg/day alcohol via gastric intubation from postnatal days (PD) 4-9, a period of brain development equivalent to late gestation in humans. A sham-intubated control group was included. From PD 10-30, subjects received subcutaneous injections of 100 mg/kg choline chloride or vehicle. Beginning on PD 32-34, subjects were trained on either delay or trace eyeblink conditioning. Performance of subjects exposed to alcohol was significantly impaired on both tasks, as indicated by significant reductions in percentage and amplitude of conditioned eyeblink responses, an effect that was attenuated by choline supplementation on the trace, but not delay conditioning task. Indeed, alcohol-exposed subjects treated with choline performed at control levels on the trace eyeblink conditioning task. There were no significant main or interactive effects of sex. These data indicate that choline supplementation can significantly reduce the

  1. Extinction, Reacquisition, and Rapid Forgetting of Eyeblink Conditioning in Developing Rats

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    Brown, Kevin L.; Freeman, John H.

    2014-01-01

    Eyeblink conditioning is a well-established model for studying the developmental neurobiology of associative learning and memory. However, age differences in extinction and subsequent reacquisition have yet to be studied using this model. The present study examined extinction and reacquisition of eyeblink conditioning in developing rats. In…

  2. Retention and Extinction of Delay Eyeblink Conditioning Are Modulated by Central Cannabinoids

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    Steinmetz, Adam B.; Freeman, John H.

    2011-01-01

    Rats administered the cannabinoid agonist WIN55,212-2 or the antagonist SR141716A exhibit marked deficits during acquisition of delay eyeblink conditioning, as noted by Steinmetz and Freeman in an earlier study. However, the effects of these drugs on retention and extinction of eyeblink conditioning have not been assessed. The present study…

  3. Extinction, Reacquisition, and Rapid Forgetting of Eyeblink Conditioning in Developing Rats

    Science.gov (United States)

    Brown, Kevin L.; Freeman, John H.

    2014-01-01

    Eyeblink conditioning is a well-established model for studying the developmental neurobiology of associative learning and memory. However, age differences in extinction and subsequent reacquisition have yet to be studied using this model. The present study examined extinction and reacquisition of eyeblink conditioning in developing rats. In…

  4. Bilateral nature of the conditioned eyeblink response in the rabbit: behavioral characteristics and potential mechanisms.

    Science.gov (United States)

    Lee, Taekwan; Kim, Jeansok J; Wagner, Allan R

    2008-12-01

    In Pavlovian eyeblink conditioning, the conditioned response (CR) is highly lateralized to the eye to which the unconditioned stimulus (US) has been directed. However, the initial conditioning of one eye can facilitate subsequent conditioning of the other eye, a phenomenon known as the intereye transfer (IET) effect. Because a conditioned emotional response (CER), as well as the eyeblink CR, is acquired during eyeblink conditioning and influences the development of the CR, the CER acquired in initial training can plausibly account for the IET effect. To evaluate this possibility, the present study utilized previously determined eyeblink conditioning procedures that effectively decouple the degree of CER and CR development to investigate the IET effect. In each of 3 experiments rabbits were initially trained with comparison procedures that differentially favored the development of the eyeblink CR or the CER, prior to a shift of the US to the alternate eye. The observed differences in the IET suggest that the effect depends largely on the specific development of eyeblink CRs rather than the CER. The neurobiological implications of this apparent bilaterality of the eyeblink CR are discussed.

  5. Eyeblink conditioning: a non-invasive biomarker for neurodevelopmental disorders.

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    Reeb-Sutherland, Bethany C; Fox, Nathan A

    2015-02-01

    Eyeblink conditioning (EBC) is a classical conditioning paradigm typically used to study the underlying neural processes of learning and memory. EBC has a well-defined neural circuitry, is non-invasive, and can be employed in human infants shortly after birth making it an ideal tool to use in both developing and special populations. In addition, abnormalities in the cerebellum, a region of the brain highly involved in EBC, have been implicated in a number of neurodevelopmental disorders including autism spectrum disorders (ASDs). In the current paper, we review studies that have employed EBC as a biomarker for several neurodevelopmental disorders including fetal alcohol syndrome, Down syndrome, fragile X syndrome, attention deficit/hyperactivity disorder, dyslexia, specific language impairment, and schizophrenia. In addition, we discuss the benefits of using such a tool in individuals with ASD.

  6. Hippocampal ripple-contingent training accelerates trace eyeblink conditioning and retards extinction in rabbits.

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    Nokia, Miriam S; Penttonen, Markku; Wikgren, Jan

    2010-08-25

    There are at least two distinct oscillatory states of the hippocampus that are related to distinct behavioral patterns. Theta (4-12 Hz) oscillation has been suggested to indicate selective attention during which the animal concentrates on some features of the environment while suppressing reactivity to others. In contrast, sharp-wave ripples ( approximately 200 Hz) can be seen in a state in which the hippocampus is at its most responsive to any kind of afferent stimulation. In addition, external stimulation tends to evoke and reset theta oscillation, the phase of which has been shown to modulate synaptic plasticity in the hippocampus. Theoretically, training on a hippocampus-dependent learning task contingent upon ripples could enhance learning rate due to elevated responsiveness and enhanced phase locking of the theta oscillation. We used a brain-computer interface to detect hippocampal ripples in rabbits to deliver trace eyeblink conditioning and extinction trials selectively contingent upon them. A yoked control group was trained regardless of their ongoing neural state. Ripple-contingent training expedited acquisition of the conditioned response early in training and evoked stronger theta-band phase locking to the conditioned stimulus. Surprisingly, ripple-contingent training also resulted in slower extinction in well trained animals. We suggest that the ongoing oscillatory activity in the hippocampus determines the extent to which a stimulus can induce a phase reset of the theta oscillation, which in turn is the determining factor of learning rate in trace eyeblink conditioning.

  7. The effects of ethanol on the developing cerebellum and eyeblink classical conditioning.

    Science.gov (United States)

    Green, John T

    2004-01-01

    In rats, developmental ethanol exposure has been used to model the central nervous system deficits associated with human fetal alcohol syndrome. Binge-like ethanol exposure of neonatal rats depletes cells in the cerebellum, including Purkinje cells, granule cells, and deep nuclear cells, and produces deficits in simple tests of motor coordination. However, the extent to which anatomical damage is related to behavioral deficits has been difficult to estimate. Eyeblink classical conditioning is known to engage a discrete brain stem-cerebellar circuit, making it an ideal test of cerebellar functional integrity after developmental ethanol exposure. Eyeblink conditioning is a simple form of motor learning in which a neutral stimulus (such as a tone) comes to elicit an eyeblink when repeatedly paired with a stimulus that evokes an eyeblink prior to training (such as mild periorbital stimulation). In eyeblink conditioning, one of the deep cerebellar nuclei, the interpositus nucleus, as well as specific Purkinje cell populations, are sites of convergence for tone conditioned stimulus and somatosensory unconditioned stimulus information, and, together with brain stem nuclei, provide the necessary and sufficient substrate for the learned response. A series of studies have shown that eyeblink conditioning is impaired in both weanling and adult rats given binge-like exposure to ethanol as neonates. In addition, interpositus nucleus neurons from ethanol-exposed rats showed impaired activation during eyeblink conditioning. These deficits are accompanied by a permanent reduction In the deep cerebellar nuclear cell population. Because particular cerebellar cell populations are utilized in well-defined ways during eyeblink conditioning, conclusions regarding the underlying neural substrates of behavioral change after developmental ethanol exposure are greatly strengthened.

  8. Eyeblink Classical Conditioning in Alcoholism and Fetal Alcohol Spectrum Disorders.

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    Cheng, Dominic T; Jacobson, Sandra W; Jacobson, Joseph L; Molteno, Christopher D; Stanton, Mark E; Desmond, John E

    2015-01-01

    Alcoholism is a debilitating disorder that can take a significant toll on health and professional and personal relationships. Excessive alcohol consumption can have a serious impact on both drinkers and developing fetuses, leading to long-term learning impairments. Decades of research in laboratory animals and humans have demonstrated the value of eyeblink classical conditioning (EBC) as a well-characterized model system to study the neural mechanisms underlying associative learning. Behavioral EBC studies in adults with alcohol use disorders and in children with fetal alcohol spectrum disorders report a clear learning deficit in these two patient populations, suggesting alcohol-related damage to the cerebellum and associated structures. Insight into the neural mechanisms underlying these learning impairments has largely stemmed from laboratory animal studies. In this mini-review, we present and discuss exemplary animal findings and data from patient and neuroimaging studies. An improved understanding of the neural mechanisms underlying learning deficits in EBC related to alcoholism and prenatal alcohol exposure has the potential to advance the diagnoses, treatment, and prevention of these and other pediatric and adult disorders.

  9. Children with autism spectrum disorders show abnormal conditioned response timing on delay, but not trace, eyeblink conditioning.

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    Oristaglio, J; Hyman West, S; Ghaffari, M; Lech, M S; Verma, B R; Harvey, J A; Welsh, J P; Malone, R P

    2013-09-17

    Children with autism spectrum disorder (ASD) and age-matched typically-developing (TD) peers were tested on two forms of eyeblink conditioning (EBC), a Pavlovian associative learning paradigm where subjects learn to execute an appropriately-timed eyeblink in response to a previously neutral conditioning stimulus (CS). One version of the task, trace EBC, interposes a stimulus-free interval between the presentation of the CS and the unconditioned stimulus (US), a puff of air to the eye which causes the subjects to blink. In delay EBC, the CS overlaps in time with the delivery of the US, usually with both stimuli terminating simultaneously. ASD children performed normally during trace EBC, exhibiting no differences from TD subjects with regard to the learning rate or the timing of the conditioned response. However, when subsequently tested on delay EBC, subjects with ASD displayed abnormally-timed conditioned eye blinks that began earlier and peaked sooner than those of TD subjects, consistent with previous findings. The results suggest an impaired ability of children with ASD to properly time conditioned eye blinks which appears to be specific to delay EBC. We suggest that this deficit may reflect a dysfunction of the cerebellar cortex in which increases in the intensity or duration of sensory input can temporarily disrupt the accuracy of motor timing over short temporal intervals.

  10. Acquisition of Differential Delay Eyeblink Classical Conditioning Is Independent of Awareness

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    Smith, Christine N.; Clark, Robert E.; Manns, Joseph R.; Squire, Larry R.

    2009-01-01

    There has been debate about whether differential delay eyeblink conditioning can be acquired without awareness of the stimulus contingencies. In 4 experiments, the authors reexamined this question. Older participants were tested with a tone and white noise (Experiment 1) or with 2 tones (Experiment 2). In addition, younger participants were tested with 2 tones (Experiment 3) or with 2 tones plus the parameters from an earlier study that had reported a relationship between conditioning and awareness (Experiment 4). Participants who were designated aware of the stimulus contingencies and participants who were designated unaware exhibited equivalent levels of differential eyeblink conditioning. Awareness of stimulus contingencies is not required for differential delay eyeblink conditioning when simple conditioned stimuli are used. PMID:15727514

  11. Whisker-signaled Eyeblink Classical Conditioning in Head-fixed Mice.

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    Lin, Carmen; Disterhoft, John; Weiss, Craig

    2016-03-30

    Eyeblink conditioning is a common paradigm for investigating the neural mechanisms underlying learning and memory. To better utilize the extensive repertoire of scientific techniques available to study learning and memory at the cellular level, it is ideal to have a stable cranial platform. Because mice do not readily tolerate restraint, they are usually trained while moving about freely in a chamber. Conditioned stimulus (CS) and unconditioned stimulus (US) information are delivered and eyeblink responses recorded via a tether connected to the mouse's head. In the head-fixed apparatus presented here, mice are allowed to run as they desire while their heads are secured to facilitate experimentation. Reliable conditioning of the eyeblink response is obtained with this training apparatus, which allows for the delivery of whisker stimulation as the CS, a periorbital electrical shock as the US, and analysis of electromyographic (EMG) activity from the eyelid to detect blink responses.

  12. The effects of two forms of physical activity on eyeblink classical conditioning.

    Science.gov (United States)

    Green, John T; Chess, Amy C; Burns, Montana; Schachinger, Kira M; Thanellou, Alexandra

    2011-05-16

    Voluntary exercise, in the form of free access to a running wheel in the home cage, has been shown to improve several forms of learning and memory. Acrobatic training, in the form of learning to traverse an elevated obstacle course, has been shown to induce markers of neural plasticity in the cerebellar cortex in rodents. In three experiments, we examined the effects of these two forms of physical activity on delay eyeblink conditioning in rats. In Experiment 1, exercising rats were given 17 days of free access to a running wheel in their home cage prior to 10 days of delay eyeblink conditioning. Rats that exercised conditioned significantly better and showed a larger reflexive eyeblink unconditioned response to the periocular stimulation unconditioned stimulus than rats that did not exercise. In Experiment 2, exercising rats were given 17 days of free access to a running wheel in their home cage prior to 10 days of explicitly unpaired stimulus presentations. Rats that exercised responded the same to tone, light, and periocular stimulation as rats that did not exercise. In Experiment 3, acrobatic training rats were given 15 days of daily training on an elevated obstacle course prior to 10 days of eyeblink conditioning. Activity control rats underwent 15 days of yoked daily running in an open field. Rats that underwent acrobatic training did not differ in eyeblink conditioning from activity control rats. The ability to measure the learned response precisely, and the well-mapped neural circuitry of eyeblink conditioning offer some advantages for the study of exercise effects on learning and memory.

  13. The Effects of Two Forms of Physical Activity on Eyeblink Classical Conditioning

    Science.gov (United States)

    Green, John T.; Chess, Amy C.; Burns, Montana; Schachinger, Kira M.; Thanellou, Alexandra

    2011-01-01

    Voluntary exercise, in the form of free access to a running wheel in the home cage, has been shown to improve several forms of learning and memory. Acrobatic training, in the form of learning to traverse an elevated obstacle course, has been shown to induce markers of neural plasticity in the cerebellar cortex in rodents. In three experiments, we examined the effects of these two forms of physical activity on delay eyeblink conditioning in rats. In Experiment 1, exercising rats were given 17 days of free access to a running wheel in their home cage prior to 10 days of delay eyeblink conditioning. Rats that exercised conditioned significantly better and showed a larger reflexive eyeblink unconditioned response to the periocular stimulation unconditioned stimulus than rats that did not exercise. In Experiment 2, exercising rats were given 17 days of free access to a running wheel in their home cage prior to 10 days of explicitly unpaired stimulus presentations. Rats that exercised responded the same to tone, light, and periocular stimulation as rats that did not exercise. In Experiment 3, acrobatic training rats were given 15 days of daily training on an elevated obstacle course prior to 10 days of eyeblink conditioning. Activity control rats underwent 15 days of yoked daily running in an open field. Rats that underwent acrobatic training did not differ in eyeblink conditioning from activity control rats. The ability to measure the learned response precisely, and the well-mapped neural circuitry of eyeblink conditioning offer some advantages for the study of exercise effects on learning and memory. PMID:21238502

  14. Contrasts in Infant Classical Eyeblink Conditioning as a Function of Premature Birth

    Science.gov (United States)

    Herbert, Jane S.; Eckerman, Carol O.; Goldstein, Ricki F.; Stanton, Mark E.

    2004-01-01

    The impact of premature birth on associative learning was evaluated using simple delay eyeblink conditioning in which a tone conditional stimulus was paired with an air puff unconditional stimulus. Fourteen preterm (28-31 weeks gestation) and 11 full-term infants completed at least 3 conditioning sessions, 1 week apart, at 5 months of age…

  15. Pontine Stimulation Overcomes Developmental Limitations in the Neural Mechanisms of Eyeblink Conditioning

    Science.gov (United States)

    Freeman, John H., Jr; Rabinak, Christine A.; Campolattaro, Matthew M.

    2005-01-01

    Pontine neuronal activation during auditory stimuli increases ontogenetically between postnatal days (P) P17 and P24 in rats. Pontine neurons are an essential component of the conditioned stimulus (CS) pathway for eyeblink conditioning, providing mossy fiber input to the cerebellum. Here we examined whether the developmental limitation in pontine…

  16. Pretrial Hippocampal ?-State Differentiates Single-Unit Response Profiles during Rabbit Trace Eyeblink Conditioning

    Science.gov (United States)

    Cicchese, Joseph J.; Darling, Ryan D.; Berry, Stephen D.

    2015-01-01

    Eyeblink conditioning given in the explicit presence of hippocampal ? results in accelerated learning and enhanced multiple-unit responses, with slower learning and suppression of unit activity under non-? conditions. Recordings from putative pyramidal cells during ?-contingent training show that pretrial ?-state is linked to the probability of…

  17. Associative Plasticity in the Medial Auditory Thalamus and Cerebellar Interpositus Nucleus During Eyeblink Conditioning

    Science.gov (United States)

    Halverson, Hunter E.; Lee, Inah; Freeman, John H.

    2010-01-01

    Eyeblink conditioning, a type of associative motor learning, requires the cerebellum. The medial auditory thalamus is a necessary source of stimulus input to the cerebellum during auditory eyeblink conditioning. Nothing is currently known about interactions between the thalamus and cerebellum during associative learning. In the current study, neuronal activity was recorded in the cerebellar interpositus nucleus and medial auditory thalamus simultaneously from multiple tetrodes during auditory eyeblink conditioning to examine the relative timing of learning-related plasticity within these interconnected areas. Learning-related changes in neuronal activity correlated with the eyeblink conditioned response were evident in the cerebellum before the medial auditory thalamus over the course of training and within conditioning trials, suggesting that thalamic plasticity may be driven by cerebellar feedback. Short-latency plasticity developed in the thalamus during the first conditioning session and may reflect attention to the conditioned stimulus. Extinction training resulted in a decrease in learning-related activity in both structures and an increase in inhibition within the cerebellum. A feedback projection from the cerebellar nuclei to the medial auditory thalamus was identified, which may play a role in learning by facilitating stimulus input to the cerebellum via the thalamo-pontine projection. PMID:20592200

  18. Cholinergic Septo-Hippocampal Innervation Is Required for Trace Eyeblink Classical Conditioning

    Science.gov (United States)

    Fontan-Lozano, Angela; Troncoso, Julieta; Munera, Alejandro; Carrion, Angel Manuel; Delgado-Garcia, Jose Maria

    2005-01-01

    We studied the effects of a selective lesion in rats, with 192-IgG-saporin, of the cholinergic neurons located in the medial septum/diagonal band (MSDB) complex on the acquisition of classical and instrumental conditioning paradigms. The MSDB lesion induced a marked deficit in the acquisition, but not in the retrieval, of eyeblink classical…

  19. Cholinergic Septo-Hippocampal Innervation Is Required for Trace Eyeblink Classical Conditioning

    Science.gov (United States)

    Fontan-Lozano, Angela; Troncoso, Julieta; Munera, Alejandro; Carrion, Angel Manuel; Delgado-Garcia, Jose Maria

    2005-01-01

    We studied the effects of a selective lesion in rats, with 192-IgG-saporin, of the cholinergic neurons located in the medial septum/diagonal band (MSDB) complex on the acquisition of classical and instrumental conditioning paradigms. The MSDB lesion induced a marked deficit in the acquisition, but not in the retrieval, of eyeblink classical…

  20. Spontaneous Recovery But Not Reinstatement of the Extinguished Conditioned Eyeblink Response in the Rat

    Science.gov (United States)

    Thanellou, Alexandra; Green, John T.

    2011-01-01

    Reinstatement, the return of an extinguished conditioned response (CR) after reexposure to the unconditioned stimulus (US), and spontaneous recovery, the return of an extinguished CR with the passage of time, are two of four well-established phenomena which demonstrate that extinction does not erase the conditioned stimulus (CS)-US association. However, reinstatement of extinguished eyeblink CRs has never been demonstrated and spontaneous recovery of extinguished eyeblink CRs has not been systematically demonstrated in rodent eyeblink conditioning. In Experiment 1, US reexposure was administered 24 hours prior to a reinstatement test. In Experiment 2, US reexposure was administered 5 min prior to a reinstatement test. In Experiment 3, a long, discrete cue (a houselight), present in all phases of training and testing, served as a context within which each trial occurred to maximize context processing, which in other preparations has been shown to be required for reinstatement. In Experiment 4, an additional group was included that received footshock exposure, rather than US reexposure, between extinction and test, and contextual freezing was measured prior to test. Spontaneous recovery was robust in Experiments 3 and 4. In Experiment 4, context freezing was strong in a group given footshock exposure but not in a group given eyeshock US reexposure. There was no reinstatement observed in any experiment. With stimulus conditions that produce eyeblink conditioning and research designs that produce reinstatement in other forms of classical conditioning, we observed spontaneous recovery but not reinstatement of extinguished eyeblink CRs. This suggests that reinstatement, but not spontaneous recovery, is a preparation- or substrate-dependent phenomenon. PMID:21517145

  1. Hippocampal and Cerebellar Single-Unit Activity During Delay and Trace Eyeblink Conditioning in the Rat

    Science.gov (United States)

    Green, John T.; Arenos, Jeremy D.

    2007-01-01

    In delay eyeblink conditioning, the CS overlaps with the US and only a brainstem-cerebellar circuit is necessary for learning. In trace eyeblink conditioning, the CS ends before the US is delivered and several forebrain structures, including the hippocampus, are required for learning, in addition to a brainstem-cerebellar circuit. The interstimulus interval (ISI) between CS onset and US onset is perhaps the most important factor in classical conditioning, but studies comparing delay and trace conditioning have typically not matched these procedures in this crucial factor, so it is often difficult to determine whether results are due to differences between delay and trace or to differences in ISI. In the current study, we employed a 580-ms CS-US interval for both delay and trace conditioning and compared hippocampal CA1 activity and cerebellar interpositus nucleus activity in order to determine whether a unique signature of trace conditioning exists in patterns of single-unit activity in either structure. Long-Evans rats were chronically implanted in either CA1 or interpositus with microwire electrodes and underwent either delay eyeblink conditioning, or trace eyeblink conditioning with a 300-ms trace period between CS offset and US onset. On trials with a CR in delay conditioning, CA1 pyramidal cells showed increases in activation (relative to a pre-CS baseline) during the CS-US period in sessions 1-4 that was attenuated by sessions 5-6. In contrast, on trials with a CR in trace conditioning, CA1 pyramidal cells did not show increases in activation during the CS-US period until sessions 5-6. In sessions 5-6, increases in activation were present only to the CS and not during the trace period. For rats with interpositus electrodes, activation of interpositus neurons on CR trials was present in all sessions in both delay and trace conditioning. However, activation was greater in trace compared to delay conditioning in the first half of the CS-US interval (during the

  2. Predictive nature of prefrontal theta oscillation on the performance of trace conditioned eyeblink responses in guinea pigs.

    Science.gov (United States)

    Chen, Hao; Wang, Yi-jie; Yang, Li; Hu, Chen; Ke, Xian-feng; Fan, Zheng-li; Sui, Jian-feng; Hu, Bo

    2014-05-15

    Stimulus-evoked theta oscillations are observed in the medial prefrontal cortex (mPFC) when executing a variety of learning tasks. Here, we aimed to further determine whether spontaneous theta-band (5.0-10.0 Hz) oscillations in the mPFC predicted the subsequent behavioral performance in trace eyeblink conditioning (TEBC), in which the conditioned stimulus (CS) was separated from the unconditioned stimulus (US) by 500 ms trace interval. By recording local field potentials (LFP) signals in the guinea pigs performing the TEBC task, we found that, a higher mPFC relative theta ratio [theta/(delta+beta)] during the baseline (850-ms period prior to the onset of the CS) was predictive of higher magnitude and more adaptive timing rather than faster acquisition of trace conditioned eyeblink responses (CR). However, the prediction of baseline mPFC theta activity was time-limited to the well-learning stage. Additionally, the relative power of mPFC theta activity did not correlate with the CR performance if the trace interval between the CS and the US was shortened to 100 ms. These results suggest that the brain state in which the baseline mPFC theta activity is present or absent is detrimental for the subsequent performance of trace CRs especially when the asymptotic learning state is achieved.

  3. Hippocampal theta phase-contingent memory retrieval in delay and trace eyeblink conditioning.

    Science.gov (United States)

    Waselius, Tomi; Pöllänen, Eveliina; Wikgren, Jan; Penttonen, Markku; Nokia, Miriam S

    2017-09-04

    Hippocampal theta oscillations (3-12Hz) play a prominent role in learning. It has been suggested that encoding and retrieval of memories are supported by different phases of the theta cycle. Our previous study on trace eyeblink conditioning in rabbits suggests that the timing of the conditioned stimulus (CS) in relation to theta phase affects encoding but not retrieval of the memory trace. Here, we directly tested the effects of hippocampal theta phase on memory retrieval in two experiments conducted on adult female New Zealand White rabbits. In Experiment 1, animals were trained in trace eyeblink conditioning followed by extinction, and memory retrieval was tested by presenting the CS at troughs and peaks of the theta cycle during different stages of learning. In Experiment 2, animals were trained in delay conditioning either contingent on a high level of theta or at a random neural state. Conditioning was then followed by extinction conducted either at a random state, contingent on theta trough or contingent on theta peak. Our current results indicate that the phase of theta at CS onset has no effect on the performance of the behavioral learned response at any stage of classical eyeblink conditioning or extinction. In addition, theta-contingent trial presentation does not improve learning during delay eyeblink conditioning. The results are consistent with our earlier findings and suggest that the theta phase alone is not sufficient to affect learning at the behavioral level. It seems that the retrieval of recently acquired memories and consequently performing a learned response is moderated by neural mechanisms other than hippocampal theta. Copyright © 2017. Published by Elsevier B.V.

  4. Eyeblink conditioning in unmedicated schizophrenia patients: a positron emission tomography study.

    Science.gov (United States)

    Parker, Krystal L; Andreasen, Nancy C; Liu, Dawei; Freeman, John H; O'Leary, Daniel S

    2013-12-30

    Previous studies suggest that patients with schizophrenia exhibit dysfunctions in a widely distributed circuit-the cortico-cerebellar-thalamic-cortical circuit, or CCTCC-and that this may explain the multiple cognitive deficits observed in the disorder. This study uses positron emission tomography (PET) with O(15) H₂O to measure regional cerebral blood flow (rCBF) in response to a classic test of cerebellar function, the associative learning that occurs during eyeblink conditioning, in a sample of 20 unmedicated schizophrenia patients and 20 closely matched healthy controls. The PET paradigm examined three phases of acquisition and extinction (early, middle and late). The patients displayed impaired behavioral performance during both acquisition and extinction. The imaging data indicate that, compared to the control subjects, the patients displayed decreases in rCBF in all three components of the CCTCC during both acquisition and extinction. Specifically, patients had less rCBF in the middle and medial frontal lobes, anterior cerebellar lobules I/V and VI, as well as the thalamus during acquisition and although similar areas were found in the frontal lobe, ipsilateral cerebellar lobule IX showed consistently less activity in patients during extinction. Thus this study provides additional support for the hypothesis that patients with schizophrenia have a cognitive dysmetria--an inability to smoothly coordinate many different types of mental activity--that affects even a very basic cognitive task that taps into associative learning.

  5. Impaired eye-blink conditioning in waggler, a mutant mouse with cerebellar BDNF deficiency.

    Science.gov (United States)

    Bao, S; Chen, L; Qiao, X; Knusel, B; Thompson, R F

    1998-01-01

    In addition to their trophic functions, neurotrophins are also implicated in synaptic modulation and learning and memory. Although gene knockout techniques have been used widely in studying the roles of neurotrophins at molecular and cellular levels, behavioral studies using neurotrophin knockouts are limited by the early-onset lethality and various sensory deficits associated with the gene knockout mice. In the present study, we found that in a spontaneous mutant mouse, waggler, the expression of brain-derived neurotrophic factor (BDNF) was selectively absent in the cerebellar granule cells. The cytoarchitecture of the waggler cerebellum appeared to be normal at the light microscope level. The mutant mice exhibited no sensory deficits to auditory stimuli or heat-induced pain. However, they were massively impaired in classic eye-blink conditioning. These results suggest that BDNF may have a role in normal cerebellar neuronal function, which, in turn, is essential for classic eye-blink conditioning.

  6. Classical eyeblink conditioning using electrical stimulation of caudal mPFC as conditioned stimulus is dependent on cerebellar interpositus nucleus in guinea pigs

    Institute of Scientific and Technical Information of China (English)

    Guang-yan WU; Juan YAO; Zheng-li FAN; Lang-qian ZHANG; Xuan LI; Chuang-dong ZHAO; Zhen-hua ZHOU; Jian-feng SUI

    2012-01-01

    Aim:To determine whether electrical stimulation of caudal medial prefrontal cortex (mPFC) as conditioned stimulus (CS) paired with airpuff unconditioned stimulus (US) was sufficient for establishing eyeblink conditioning in guinea pigs,and whether it was dependent on cerebellar interpositus nucleus.Methods:Thirty adult guinea pigs were divided into 3 conditioned groups,and trained on the delay eyeblink conditioning,short-trace eyeblink conditioning,and long-trace eyeblink conditioning paradigms,respectively,in which electrical stimulation of the right caudal mPFC was used as CS and paired with corneal airpuff US.A pseudo conditioned group of another 10 adult guinea pigs was given unpaired caudal mPFC electrical stimulation and the US.Muscimol (1 μg in 1 μL saline) and saline (1 μL) were infused into the cerebellar interpositus nucleus of the animals through the infusion cannula on d 11 and 12,respectively.Results:The 3 eyeblink conditioning paradigms have been successfully established in guinea pigs.The animals acquired the delay and short-trace conditioned responses more rapidly than long-trace conditioned responses.Muscimol infusion into the cerebellar interpositus nucleus markedly impaired the expression of the 3 eyeblink conditioned responses.Conclusion:Electrical stimulation of caudal mPFC is effective CS for establishing eyeblink conditioning in guinea pigs,and it is dependent on the cerebellar interpositus nucleus.

  7. Facilitated acquisition of eyeblink conditioning in those vulnerable to anxiety disorders

    Directory of Open Access Journals (Sweden)

    Meghan Davis Caulfield

    2013-07-01

    Full Text Available Behavioral inhibition (BI increases vulnerability to develop anxiety disorders and is typified by avoidance and withdrawal from novel objects, people, and situations. The present study considered the relationship between behavioral inhibition and temperamental risk factors, such as trait anxiety and acquisition rate of a classically conditioned eyeblink response. 174 healthy undergraduate students (mean age 20.3 years, 71.8% female were given the State-Trait Anxiety Inventory and a battery of self-report measures of behavioral inhibition consisting of the Adult and Retrospective Measures of Behavioural Inhibition (AMBI/RMBI and the Concurrent and Retrospective Self Report of Inhibition (CSRI/RSRI. Participants then underwent standard delay classical eyeblink conditioning consisting of 45 trials with a 500-ms CS overlapping and co-terminating with a 10-ms airpuff US. Individuals with higher scores on the AMBI and Trait Anxiety Inventory, but not the other measures, showed faster acquisition of a conditioned eyeblink response than individuals with lower scores. Results support a relationship between facilitated acquisition of inter-stimulus relationships and risk for anxiety, and suggest that some measures assessing anxiety vulnerability better capture this relationship than others.

  8. Deep cerebellar nuclei play an important role in two-tone discrimination on delay eyeblink conditioning in C57BL/6 mice.

    Science.gov (United States)

    Sakamoto, Toshiro; Endo, Shogo

    2013-01-01

    Previous studies have shown that deep cerebellar nuclei (DCN)-lesioned mice develop conditioned responses (CR) on delay eyeblink conditioning when a salient tone conditioned stimulus (CS) is used, which suggests that the cerebellum potentially plays a role in more complicated cognitive functions. In the present study, we examined the role of DCN in tone frequency discrimination in the delay eyeblink-conditioning paradigm. In the first experiment, DCN-lesioned and sham-operated mice were subjected to standard simple eyeblink conditioning under low-frequency tone CS (LCS: 1 kHz, 80 dB) or high-frequency tone CS (HCS: 10 kHz, 70 dB) conditions. DCN-lesioned mice developed CR in both CS conditions as well as sham-operated mice. In the second experiment, DCN-lesioned and sham-operated mice were subjected to two-tone discrimination tasks, with LCS+ (or HCS+) paired with unconditioned stimulus (US), and HCS- (or LCS-) without US. CR% in sham-operated mice increased in LCS+ (or HCS+) trials, regardless of tone frequency of CS, but not in HCS- (or LCS-) trials. The results indicate that sham-operated mice can discriminate between LCS+ and HCS- (or HCS+ and LCS-). In contrast, DCN-lesioned mice showed high CR% in not only LCS+ (or HCS+) trials but also HCS- (or LCS-) trials. The results indicate that DCN lesions impair the discrimination between tone frequency in eyeblink conditioning. Our results suggest that the cerebellum plays a pivotal role in the discrimination of tone frequency.

  9. Deep cerebellar nuclei play an important role in two-tone discrimination on delay eyeblink conditioning in C57BL/6 mice.

    Directory of Open Access Journals (Sweden)

    Toshiro Sakamoto

    Full Text Available Previous studies have shown that deep cerebellar nuclei (DCN-lesioned mice develop conditioned responses (CR on delay eyeblink conditioning when a salient tone conditioned stimulus (CS is used, which suggests that the cerebellum potentially plays a role in more complicated cognitive functions. In the present study, we examined the role of DCN in tone frequency discrimination in the delay eyeblink-conditioning paradigm. In the first experiment, DCN-lesioned and sham-operated mice were subjected to standard simple eyeblink conditioning under low-frequency tone CS (LCS: 1 kHz, 80 dB or high-frequency tone CS (HCS: 10 kHz, 70 dB conditions. DCN-lesioned mice developed CR in both CS conditions as well as sham-operated mice. In the second experiment, DCN-lesioned and sham-operated mice were subjected to two-tone discrimination tasks, with LCS+ (or HCS+ paired with unconditioned stimulus (US, and HCS- (or LCS- without US. CR% in sham-operated mice increased in LCS+ (or HCS+ trials, regardless of tone frequency of CS, but not in HCS- (or LCS- trials. The results indicate that sham-operated mice can discriminate between LCS+ and HCS- (or HCS+ and LCS-. In contrast, DCN-lesioned mice showed high CR% in not only LCS+ (or HCS+ trials but also HCS- (or LCS- trials. The results indicate that DCN lesions impair the discrimination between tone frequency in eyeblink conditioning. Our results suggest that the cerebellum plays a pivotal role in the discrimination of tone frequency.

  10. Cerebellar-dependent associative learning is preserved in Duchenne muscular dystrophy: a study using delay eyeblink conditioning.

    Directory of Open Access Journals (Sweden)

    Ulrike Schara

    Full Text Available Besides progressive muscle weakness cognitive deficits have been reported in patients with Duchenne muscular dystrophy (DMD. Cerebellar dysfunction has been proposed to explain cognitive deficits at least in part. In animal models of DMD disturbed Purkinje cell function has been shown following loss of dystrophin. Furthermore there is increasing evidence that the lateral cerebellum contributes to cognitive processing. In the present study cerebellar-dependent delay eyeblink conditioning, a form of associative learning, was used to assess cerebellar function in DMD children.Delay eyeblink conditioning was examined in eight genetically defined male patients with DMD and in ten age-matched control subjects. Acquisition, timing and extinction of conditioned eyeblink responses (CR were assessed during a single conditioning session.Both groups showed a significant increase of CRs during the course of learning (block effect p < 0.001. CR acquisition was not impaired in DMD patients (mean total CR incidence 37.4 ± 17.6% as compared to control subjects (36.2 ± 17.3%; group effect p = 0.89; group by block effect p = 0.38; ANOVA with repeated measures. In addition, CR timing and extinction was not different from controls.Delay eyeblink conditioning was preserved in the present DMD patients. Because eyeblink conditioning depends on the integrity of the intermediate cerebellum, this older part of the cerebellum may be relatively preserved in DMD. The present findings agree with animal model data showing that the newer, lateral cerebellum is primarily affected in DMD.

  11. Purkinje cell activity in the cerebellar anterior lobe after rabbit eyeblink conditioning

    Science.gov (United States)

    Green, John T.; Steinmetz, Joseph E.

    2005-01-01

    The cerebellar anterior lobe may play a critical role in the execution and proper timing of learned responses. The current study was designed to monitor Purkinje cell activity in the rabbit cerebellar anterior lobe after eyeblink conditioning, and to assess whether Purkinje cells in recording locations may project to the interpositus nucleus. Rabbits were trained in an interstimulus interval discrimination procedure in which one tone signaled a 250-msec conditioned stimulus-unconditioned stimulus (CS-US) interval and a second tone signaled a 750-msec CS-US interval. All rabbits showed conditioned responses to each CS with mean onset and peak latencies that coincided with the CS-US interval. Many anterior lobe Purkinje cells showed significant learning-related activity after eyeblink conditioning to one or both of the CSs. More Purkinje cells responded with inhibition than with excitation to CS presentation. In addition, when the firing patterns of all conditioning-related Purkinje cells were pooled, it appeared that the population showed a pattern of excitation followed by inhibition during the CS-US interval. Using cholera toxin-conjugated horseradish peroxidase, Purkinje cells in recording areas were found to project to the interpositus nucleus. These data support previous studies that have suggested a role for the anterior cerebellar cortex in eyeblink conditioning as well as models of cerebellar-mediated CR timing that postulate that Purkinje cell activity inhibits conditioned response (CR) generation during the early portion of a trial by inhibiting the deep cerebellar nuclei and permits CR generation during the later portion of a trial through disinhibition of the cerebellar nuclei. PMID:15897252

  12. Cortical spreading depression and involvement of the motor cortex, auditory cortex, and cerebellum in eyeblink classical conditioning of the rabbit.

    Science.gov (United States)

    Case, Gilbert R; Lavond, David G; Thompson, Richard F

    2002-09-01

    The interrelationships of cerebellar and cerebral neural circuits in the eyeblink paradigm were explored with the controlled application of cortical spreading depression (CSD) and lidocaine in the New Zealand albino rabbit. The initial research focus was directed toward the involvement of the motor cortex in the conditioned eyeblink response. However, CSD timing and triangulation results indicate that other areas in the cerebral cortex, particularly the auditory cortex (acoustic conditioned stimulus), appear to be critical for the CSD effect on the eyeblink response. In summary: (1) CSD can be elicited, monitored, and timed and its side effects controlled in 97% of awake rabbits in the right and/or left cerebral hemisphere(s) during eyeblink conditioning. (2) The motor cortex appears to play little or no part in classical conditioning of the eyeblink in the rabbit in the delay paradigm. (3) Inactivating the auditory cortex with CSD or lidocaine temporarily impairs the conditioned response during the first 5 to 15 days of training, but has little effect past that point.

  13. Central amygdala lesions inhibit pontine nuclei acoustic reactivity and retard delay eyeblink conditioning acquisition in adult rats.

    Science.gov (United States)

    Pochiro, Joseph M; Lindquist, Derick H

    2016-06-01

    In delay eyeblink conditioning (EBC) a neutral conditioned stimulus (CS; tone) is repeatedly paired with a mildly aversive unconditioned stimulus (US; periorbital electrical shock). Over training, subjects learn to produce an anticipatory eyeblink conditioned response (CR) during the CS, prior to US onset. While cerebellar synaptic plasticity is necessary for successful EBC, the amygdala is proposed to enhance eyeblink CR acquisition. In the current study, adult Long-Evans rats received bilateral sham or neurotoxic lesions of the central nucleus of the amygdala (CEA) followed by 1 or 4 EBC sessions. Fear-evoked freezing behavior, CS-mediated enhancement of the unconditioned response (UR), and eyeblink CR acquisition were all impaired in the CEA lesion rats relative to sham controls. There were also significantly fewer c-Fos immunoreactive cells in the pontine nuclei (PN)-major relays of acoustic information to the cerebellum-following the first and fourth EBC session in lesion rats. In sham rats, freezing behavior decreased from session 1 to 4, commensurate with nucleus-specific reductions in amygdala Fos+ cell counts. Results suggest delay EBC proceeds through three stages: in stage one the amygdala rapidly excites diffuse fear responses and PN acoustic reactivity, facilitating cerebellar synaptic plasticity and the development of eyeblink CRs in stage two, leading, in stage three, to a diminution or stabilization of conditioned fear responding.

  14. Facilitated acquisition of standard but not long delay classical eyeblink conditioning in behaviorally inhibited adolescents.

    Science.gov (United States)

    Caulfield, M D; VanMeenen, K M; Servatius, R J

    2015-02-01

    Adolescence is a key age in the development of anxiety disorders. The present study assessed the relationship between behavioral inhibition, a risk factor for anxiety typified by avoidance, and acquisition of the classically conditioned eyeblink response. 168 healthy high school students (mean age 15.7 years, 54% female) were given a battery of self-report measures including the Adult Measure of Behavioural Inhibition (AMBI). The study compared acquisition of three experimental training conditions. Two groups were given paired CS-US training: standard delay of 500-ms or long delay of 1000-ms with CS overlapping and co-terminating with a 50-ms airpuff US. A third group received unpaired training of 1000-ms CS and 50-ms airpuff US. Inhibited individuals showed greater acquisition of the conditioned eyeblink response in the 500-ms CS condition, but not in the paired 1000-ms condition. No differences in spontaneous blinks or reactivity to the stimulus were evident in the 1000-ms unpaired CS condition. Results support a relationship between associative learning and anxiety vulnerability that may be mediated by cerebellar functioning in inhibited individuals.

  15. Relational and procedural memory systems in the goldfish brain revealed by trace and delay eyeblink-like conditioning.

    Science.gov (United States)

    Gómez, A; Rodríguez-Expósito, B; Durán, E; Martín-Monzón, I; Broglio, C; Salas, C; Rodríguez, F

    2016-12-01

    The presence of multiple memory systems supported by different neural substrata has been demonstrated in animal and human studies. In mammals, two variants of eyeblink classical conditioning, differing only in the temporal relationships between the conditioned stimulus (CS) and the unconditioned stimulus (US), have been widely used to study the neural substrata of these different memory systems. Delay conditioning, in which both stimuli coincide in time, depends on a non-relational memory system supported by the cerebellum and associated brainstem circuits. In contrast, trace conditioning, in which a stimulus-free time gap separates the CS and the US, requires a declarative or relational memory system, thus depending on forebrain structures in addition to the cerebellum. The distinction between the explicit or relational and the implicit or procedural memory systems that support trace and delay classical conditioning has been extensively studied in mammals, but studies in other vertebrate groups are relatively scarce. In the present experiment we analyzed the differential involvement of the cerebellum and the telencephalon in delay and trace eyeblink-like classical conditioning in goldfish. The results show that whereas the cerebellum lesion prevented the eyeblink-like conditioning in both procedures, the telencephalon ablation impaired exclusively the acquisition of the trace conditioning. These data showing that comparable neural systems support delay and trace eyeblink conditioning in teleost fish and mammals suggest that these separate memory systems and their neural bases could be a shared ancestral brain feature of the vertebrate lineage. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Stimulation of the Lateral Geniculate, Superior Colliculus, or Visual Cortex is Sufficient for Eyeblink Conditioning in Rats

    Science.gov (United States)

    Halverson, Hunter E.; Hubbard, Erin M.; Freeman, John H.

    2009-01-01

    The role of the cerebellum in eyeblink conditioning is well established. Less work has been done to identify the necessary conditioned stimulus (CS) pathways that project sensory information to the cerebellum. A possible visual CS pathway has been hypothesized that consists of parallel inputs to the pontine nuclei from the lateral geniculate…

  17. Dimethoate accelerates the extinction of eyeblink conditioning in mice.

    Science.gov (United States)

    Valenzuela-Harrington, Mauricio; Castillo, Irene; Díaz, Corín; Alés, Inés; Rodríguez-Moreno, Antonio

    2012-01-01

    In agriculture, organophosphates are frequently used as insecticides and pesticides. These compounds decrease acetylcholine esterase (AChE) activity, thereby provoking an accumulation of the neurotransmitter acetylcholine at synapses and resulting in the over-stimulation of acetylcholine receptors. Using trace paradigms, we investigated the effects of dimethoate, a widely used organophosphate insecticide, on the classical conditioning of eyelid responses, a hippocampal-dependent mouse model of associative learning. Mice were conditioned with a trace shock-SHOCK paradigm having first implanted stimulating electrodes in the supraorbitary nerve and recording electrodes in the ipsilateral orbicularis oculi muscle. When these mice were injected with dimethoate (5, 20, 50mg/kg/day) they were capable of acquiring associative learning, and the latency and amplitude of their unconditioned eyelid responses were unaffected by the administration of the pesticide. However, dimethoate administration led to the rapid extinction of conditioned responses, suggesting that this organophosphate accelerates the extinction of this form of associative learning. Analysis of the motor function of these mice using the rotarod performance test revealed that motor function and performance clearly deteriorated following dimethoate administration, with no improvements over the following 4 days. Together these findings indicate that dimethoate accelerates the extinction of acquired conditioned responses, affecting associative learning and memory, and it impairs motor function and performance in mice.

  18. The role of US recency in the Perruchet effect in eyeblink conditioning.

    Science.gov (United States)

    Weidemann, Gabrielle; Lovibond, Peter F

    2016-09-01

    In the Perruchet effect, there is a concurrent dissociation between participants' conditioned responses (CRs) and their expectancy of the unconditioned stimulus (US) across runs of repeated trials. The effect has been taken as evidence for multiple learning processes, but this conclusion follows only if the CR trend is the result of learning. Two experiments examined the role of US recency in generating the observed CR trend. A standard Perruchet condition was compared with a control condition in which US recency was controlled by presenting the US on every trial. The associative contribution was maintained by varying the temporal relationship between the CS and the US. In both experiments the pattern of CRs seen in the Perruchet condition was absent in the control condition, suggesting that the eyeblink trend in the Perruchet effect may be due to a non-associative performance factor such as priming or sensitization arising from recent US presentations.

  19. Prolonging the postcomplex spike pause speeds eyeblink conditioning.

    Science.gov (United States)

    Maiz, Jaione; Karakossian, Movses H; Pakaprot, Narawut; Robleto, Karla; Thompson, Richard F; Otis, Thomas S

    2012-10-09

    Climbing fiber input to the cerebellum is believed to serve as a teaching signal during associative, cerebellum-dependent forms of motor learning. However, it is not understood how this neural pathway coordinates changes in cerebellar circuitry during learning. Here, we use pharmacological manipulations to prolong the postcomplex spike pause, a component of the climbing fiber signal in Purkinje neurons, and show that these manipulations enhance the rate of learning in classical eyelid conditioning. Our findings elucidate an unappreciated aspect of the climbing fiber teaching signal, and are consistent with a model in which convergent postcomplex spike pauses drive learning-related plasticity in the deep cerebellar nucleus. They also suggest a physiological mechanism that could modulate motor learning rates.

  20. Effects of Paradigm and Inter-Stimulus Interval on Age Differences in Eyeblink Classical Conditioning in Rabbits

    Science.gov (United States)

    Woodruff-Pak, Diana S.; Seta, Susan E.; Roker, LaToya A.; Lehr, Melissa A.

    2007-01-01

    The aim of this study was to examine parameters affecting age differences in eyeblink classical conditioning in a large sample of young and middle-aged rabbits. A total of 122 rabbits of mean ages of 4 or 26 mo were tested at inter-stimulus intervals (ISIs) of 600 or 750 msec in the delay or trace paradigms. Paradigm affected both age groups…

  1. Using eyeblink classical conditioning as a test of the functional consequences of exposure of the developing cerebellum to alcohol.

    Science.gov (United States)

    Green, John T

    2003-01-01

    Exposure of the developing brain to alcohol produces profound Purkinje cell loss in the cerebellum, and deficits in tests of motor coordination. However, the precise relationship between these two sets of findings has been difficult to determine. Eyeblink classical conditioning is known to engage a discrete brainstem-cerebellar circuit, making it an ideal test of cerebellar functional integrity after developmental alcohol exposure. In eyeblink conditioning, one of the deep cerebellar nuclei, the interpositus nucleus, as well as specific Purkinje cell populations, are sites of convergence for CS and US information. A series of studies have shown that eyeblink conditioning is impaired in both weanling and adult rats given binge-like exposure to alcohol as neonates, and that these deficits can be traced, at least in part, to impaired activation of cerebellar interpositus nucleus neurons and to an overall reduction in the deep cerebellar nuclear cell population. Because particular cerebellar cell populations are utilized in well-defined ways during eyeblink conditioning, conclusions regarding specific changes in the mediation of behavior by these cell populations are greatly strengthened. Further studies will be directed towards the impact of early exposure to alcohol on the functionality of specific Purkinje cell populations, as well as towards brainstem areas that process the tone CS and the somatosensory US.

  2. Project DyAdd: classical eyeblink conditioning in adults with dyslexia and ADHD.

    Science.gov (United States)

    Laasonen, Marja; Kauppinen, Jenni; Leppämäki, Sami; Tani, Pekka; Harno, Hanna; Hokkanen, Laura; Wikgren, Jan

    2012-11-01

    In this study of the project DyAdd (Adult Dyslexia and Attention Deficit Disorder in Finland), classical eyeblink conditioning (EBC) was investigated in both delay and trace paradigms in adults (18-55 years) with dyslexia (n = 37), attention deficit-hyperactivity disorder (ADHD; n = 21), their comorbid combination (n = 8), and healthy controls (n = 35). In addition, the profiles of three participants with a rare autosomal dominant cerebellar disease were assessed (episodic ataxia type 2, EA-2). We found that participants with dyslexia were overall slower learners than controls in eyeblink conditioning. Further, they were the only group that had a reduced number of CRs in mediotemporal-dependent trace paradigm compared to the more cerebellum-dependent delay paradigm. Second, ADHD was found to be related to larger CR amplitude. Third, those with a comorbid condition learned faster and manifested CRs that were not well timed. Fourth, the cerebellar patients showed nearly no conditioning at all. Correlations between EBC and various neuropsychological domains (phonological processing, reading, spelling, arithmetic, executive functions, attention, and fine motor control) over all participants resulted in significant relations only for the delay paradigm: Increased amount of reading errors related with later peak latency and increased amount of self-corrections in fine motor control related with larger response magnitude. Within those who conditioned, relations emerged only for the trace paradigm: better spelling was related to larger response magnitude. These results do not lend support to the cerebellar hypothesis of dyslexia. On the contrary, dyslexia in its pure form seems to be related to a relative dysfunction of a larger hippocampal-cerebellar network. Further, larger responses in the ADHD group are suggested to result from their lowered responding threshold.

  3. Savings and extinction of conditioned eyeblink responses in fragile X syndrome

    DEFF Research Database (Denmark)

    Smit, A E; van der Geest, J N; Vellema, M

    2008-01-01

    with FRAXA. In the present behavioral study, long-term effects of deficiency of FMRP were investigated by examining the acquisition, savings and extinction of delay eyeblink conditioning in male individuals with FRAXA. In the acquisition experiment, subjects with FRAXA displayed a significantly poor...... performance compared with controls. In the savings experiment performed at least 6 months later, subjects with FRAXA and controls showed similar levels of savings of conditioned responses. Subsequently, extinction was faster in subjects with FRAXA than in controls. These findings confirm that absence...... of the FMRP affects cerebellar motor learning. The normal performance in the savings experiment and aberrant performance in the acquisition and extinction experiments of individuals with FRAXA suggest that different mechanisms underlie acquisition, savings and extinction of cerebellar motor learning....

  4. Cerebellar tDCS Effects on Conditioned Eyeblinks using Different Electrode Placements and Stimulation Protocols

    Science.gov (United States)

    Beyer, Linda; Batsikadze, Giorgi; Timmann, Dagmar; Gerwig, Marcus

    2017-01-01

    There is good evidence that the human cerebellum is involved in the acquisition and timing of classically conditioned eyeblink responses (CRs). Animal studies suggest that the cerebellum is also important in CR extinction and savings. Cerebellar transcranial direct current stimulation (tDCS) was reported to modulate CR acquisition and timing in a polarity dependent manner. To extent previous findings three experiments were conducted using standard delay eyeblink conditioning. In a between-group design, effects of tDCS were assessed with stimulation over the right cerebellar hemisphere ipsilaterally to the unconditioned stimulus (US). An extracephalic reference electrode was used in Experiment 1 and a cephalic reference in Experiment 2. In both parts the influence on unconditioned eyeblink responses (UR) was investigated by starting stimulation in the second half of the pseudoconditioning phase lasting throughout the first half of paired trials. In a third experiment, effects of cerebellar tDCS during 40 extinction trials were assessed on extinction and reacquisition on the next day. In each experiment, 30 subjects received anodal, cathodal or sham stimulation in a double-blinded fashion. Using the extracephalic reference electrode, no significant effects on CR incidences comparing stimulation groups were observed. Using the cephalic reference anodal as well as cathodal cerebellar tDCS increased CR acquisition compared to sham only on a trend level. Analysis of timing parameters did not reveal significant effects on CR onset and peaktime latencies nor on UR timing. In the third experiment, cerebellar tDCS during extinction trials had no significant effect on extinction and savings on the next day. The present study did not reveal clear polarity dependent effects of cerebellar tDCS on CR acquisition and timing as previously described. Weaker effects may be explained by start of tDCS before the learning phase i.e., offline, individual thresholds and current flow based

  5. Cerebellar tDCS Effects on Conditioned Eyeblinks using Different Electrode Placements and Stimulation Protocols.

    Science.gov (United States)

    Beyer, Linda; Batsikadze, Giorgi; Timmann, Dagmar; Gerwig, Marcus

    2017-01-01

    There is good evidence that the human cerebellum is involved in the acquisition and timing of classically conditioned eyeblink responses (CRs). Animal studies suggest that the cerebellum is also important in CR extinction and savings. Cerebellar transcranial direct current stimulation (tDCS) was reported to modulate CR acquisition and timing in a polarity dependent manner. To extent previous findings three experiments were conducted using standard delay eyeblink conditioning. In a between-group design, effects of tDCS were assessed with stimulation over the right cerebellar hemisphere ipsilaterally to the unconditioned stimulus (US). An extracephalic reference electrode was used in Experiment 1 and a cephalic reference in Experiment 2. In both parts the influence on unconditioned eyeblink responses (UR) was investigated by starting stimulation in the second half of the pseudoconditioning phase lasting throughout the first half of paired trials. In a third experiment, effects of cerebellar tDCS during 40 extinction trials were assessed on extinction and reacquisition on the next day. In each experiment, 30 subjects received anodal, cathodal or sham stimulation in a double-blinded fashion. Using the extracephalic reference electrode, no significant effects on CR incidences comparing stimulation groups were observed. Using the cephalic reference anodal as well as cathodal cerebellar tDCS increased CR acquisition compared to sham only on a trend level. Analysis of timing parameters did not reveal significant effects on CR onset and peaktime latencies nor on UR timing. In the third experiment, cerebellar tDCS during extinction trials had no significant effect on extinction and savings on the next day. The present study did not reveal clear polarity dependent effects of cerebellar tDCS on CR acquisition and timing as previously described. Weaker effects may be explained by start of tDCS before the learning phase i.e., offline, individual thresholds and current flow based

  6. Hippocampal Non-Theta-Contingent Eyeblink Classical Conditioning: A Model System for Neurobiological Dysfunction.

    Science.gov (United States)

    Cicchese, Joseph J; Berry, Stephen D

    2016-01-01

    Typical information processing is thought to depend on the integrity of neurobiological oscillations that may underlie coordination and timing of cells and assemblies within and between structures. The 3-7 Hz bandwidth of hippocampal theta rhythm is associated with cognitive processes essential to learning and depends on the integrity of cholinergic, GABAergic, and glutamatergic forebrain systems. Since several significant psychiatric disorders appear to result from dysfunction of medial temporal lobe (MTL) neurochemical systems, preclinical studies on animal models may be an important step in defining and treating such syndromes. Many studies have shown that the amount of hippocampal theta in the rabbit strongly predicts the acquisition rate of classical eyeblink conditioning and that impairment of this system substantially slows the rate of learning and attainment of asymptotic performance. Our lab has developed a brain-computer interface that makes eyeblink training trials contingent upon the explicit presence or absence of hippocampal theta. The behavioral benefit of theta-contingent training has been demonstrated in both delay and trace forms of the paradigm with a two- to fourfold increase in learning speed over non-theta states. The non-theta behavioral impairment is accompanied by disruption of the amplitude and synchrony of hippocampal local field potentials, multiple-unit excitation, and single-unit response patterns dependent on theta state. Our findings indicate a significant electrophysiological and behavioral impact of the pretrial state of the hippocampus that suggests an important role for this MTL system in associative learning and a significant deleterious impact in the absence of theta. Here, we focus on the impairments in the non-theta state, integrate them into current models of psychiatric disorders, and suggest how improvement in our understanding of neurobiological oscillations is critical for theories and treatment of psychiatric

  7. PKMzeta inhibition reverses learning-induced increases in hippocampal synaptic strength and memory during trace eyeblink conditioning.

    Directory of Open Access Journals (Sweden)

    Noelia Madroñal

    Full Text Available A leading candidate in the process of memory formation is hippocampal long-term potentiation (LTP, a persistent enhancement in synaptic strength evoked by the repetitive activation of excitatory synapses, either by experimental high-frequency stimulation (HFS or, as recently shown, during actual learning. But are the molecular mechanisms for maintaining synaptic potentiation induced by HFS and by experience the same? Protein kinase Mzeta (PKMzeta, an autonomously active atypical protein kinase C isoform, plays a key role in the maintenance of LTP induced by tetanic stimulation and the storage of long-term memory. To test whether the persistent action of PKMzeta is necessary for the maintenance of synaptic potentiation induced after learning, the effects of ZIP (zeta inhibitory peptide, a PKMzeta inhibitor, on eyeblink-conditioned mice were studied. PKMzeta inhibition in the hippocampus disrupted both the correct retrieval of conditioned responses (CRs and the experience-dependent persistent increase in synaptic strength observed at CA3-CA1 synapses. In addition, the effects of ZIP on the same associative test were examined when tetanic LTP was induced at the hippocampal CA3-CA1 synapse before conditioning. In this case, PKMzeta inhibition both reversed tetanic LTP and prevented the expected LTP-mediated deleterious effects on eyeblink conditioning. Thus, PKMzeta inhibition in the CA1 area is able to reverse both the expression of trace eyeblink conditioned memories and the underlying changes in CA3-CA1 synaptic strength, as well as the anterograde effects of LTP on associative learning.

  8. Implicit Memory in Monkeys: Development of a Delay Eyeblink Conditioning System with Parallel Electromyographic and High-Speed Video Measurements.

    Directory of Open Access Journals (Sweden)

    Yasushi Kishimoto

    Full Text Available Delay eyeblink conditioning, a cerebellum-dependent learning paradigm, has been applied to various mammalian species but not yet to monkeys. We therefore developed an accurate measuring system that we believe is the first system suitable for delay eyeblink conditioning in a monkey species (Macaca mulatta. Monkey eyeblinking was simultaneously monitored by orbicularis oculi electromyographic (OO-EMG measurements and a high-speed camera-based tracking system built around a 1-kHz CMOS image sensor. A 1-kHz tone was the conditioned stimulus (CS, while an air puff (0.02 MPa was the unconditioned stimulus. EMG analysis showed that the monkeys exhibited a conditioned response (CR incidence of more than 60% of trials during the 5-day acquisition phase and an extinguished CR during the 2-day extinction phase. The camera system yielded similar results. Hence, we conclude that both methods are effective in evaluating monkey eyeblink conditioning. This system incorporating two different measuring principles enabled us to elucidate the relationship between the actual presence of eyelid closure and OO-EMG activity. An interesting finding permitted by the new system was that the monkeys frequently exhibited obvious CRs even when they produced visible facial signs of drowsiness or microsleep. Indeed, the probability of observing a CR in a given trial was not influenced by whether the monkeys closed their eyelids just before CS onset, suggesting that this memory could be expressed independently of wakefulness. This work presents a novel system for cognitive assessment in monkeys that will be useful for elucidating the neural mechanisms of implicit learning in nonhuman primates.

  9. Eyeblink Classical Conditioning and Post Traumatic Stress Disorder – A Model Systems Approach

    Directory of Open Access Journals (Sweden)

    Bernard G Schreurs

    2015-04-01

    Full Text Available Not everyone exposed to trauma suffers flashbacks, bad dreams, numbing, fear, anxiety, sleeplessness, hyper-vigilance, hyperarousal, or an inability to cope, but those who do may suffer from post traumatic stress disorder (PTSD. PTSD is a major physical and mental health problem for military personnel and civilians exposed to trauma. There is still debate about the incidence and prevalence of PTSD especially among the military, but for those who are diagnosed, behavioral therapy and drug treatment strategies have proven to be less than effective. A number of these treatment strategies are based on rodent fear conditioning research and are capable of treating only some of the symptoms because the extinction of fear does not deal with the various forms of hyper-vigilance and hyperarousal experienced by people with PTSD. To help address this problem, we have developed a preclinical eyeblink classical conditioning model of PTSD in which conditioning and hyperarousal can both be extinguished. We review this model and discuss findings showing that unpaired stimulus presentations can be effective in reducing levels of conditioning and hyperarousal even when unconditioned stimulus intensity is reduced to the point where it is barely capable of eliciting a response. These procedures have direct implications for the treatment of PTSD and could be implemented in a virtual reality environment.

  10. Eyeblink classical conditioning and post-traumatic stress disorder - a model systems approach.

    Science.gov (United States)

    Schreurs, Bernard G; Burhans, Lauren B

    2015-01-01

    Not everyone exposed to trauma suffers flashbacks, bad dreams, numbing, fear, anxiety, sleeplessness, hyper-vigilance, hyperarousal, or an inability to cope, but those who do may suffer from post-traumatic stress disorder (PTSD). PTSD is a major physical and mental health problem for military personnel and civilians exposed to trauma. There is still debate about the incidence and prevalence of PTSD especially among the military, but for those who are diagnosed, behavioral therapy and drug treatment strategies have proven to be less than effective. A number of these treatment strategies are based on rodent fear conditioning research and are capable of treating only some of the symptoms because the extinction of fear does not deal with the various forms of hyper-vigilance and hyperarousal experienced by people with PTSD. To help address this problem, we have developed a preclinical eyeblink classical conditioning model of PTSD in which conditioning and hyperarousal can both be extinguished. We review this model and discuss findings showing that unpaired stimulus presentations can be effective in reducing levels of conditioning and hyperarousal even when unconditioned stimulus intensity is reduced to the point where it is barely capable of eliciting a response. These procedures have direct implications for the treatment of PTSD and could be implemented in a virtual reality environment.

  11. Investigating the Role of Hippocampal BDNF in Anxiety Vulnerability Using Classical Eyeblink Conditioning.

    Science.gov (United States)

    Janke, Kellie L; Cominski, Tara P; Kuzhikandathil, Eldo V; Servatius, Richard J; Pang, Kevin C H

    2015-01-01

    Dysregulation of brain-derived neurotrophic factor (BDNF), behavioral inhibition temperament (BI), and small hippocampal volume have been linked to anxiety disorders. Individuals with BI show facilitated acquisition of the classically conditioned eyeblink response (CCER) as compared to non-BI individuals, and a similar pattern is seen in an animal model of BI, the Wistar-Kyoto (WKY) rat. The present study examined the role of hippocampal BDNF in the facilitated delay CCER of WKY rats. Consistent with earlier work, acquisition was facilitated in WKY rats compared to the Sprague Dawley (SD) rats. Facilitated acquisition was associated with increased BDNF, TrkB, and Arc mRNA in the dentate gyrus of SD rats, but learning-induced increases in BDNF and Arc mRNA were significantly smaller in WKY rats. To determine whether reduced hippocampal BDNF in WKY rats was a contributing factor for their facilitated CCER, BDNF or saline infusions were given bilaterally into the dentate gyrus region 1 h prior to training. BDNF infusion did not alter the acquisition of SD rats, but significantly dampened the acquisition of CCER in the WKY rats, such that acquisition was similar to SD rats. Together, these results suggest that inherent differences in the BDNF system play a critical role in the facilitated associative learning exhibited by WKY rats, and potentially individuals with BI. Facilitated associative learning may represent a vulnerability factor in the development of anxiety disorders.

  12. Intra-cerebellar infusion of the protein kinase Mzeta (PKMζ) inhibitor ZIP disrupts eyeblink classical conditioning

    Science.gov (United States)

    Chihabi, Kutibh; Morielli, Anthony D.; Green, John T.

    2016-01-01

    PKM-ζ, a constitutively active N-terminal truncated form of PKC-ζ, has long been implicated in a cellular correlate of learning, long-term potentiation (LTP). Inhibition of PKM-ζ with Zeta-inhibitory peptide (ZIP) has been shown in many brain structures to disrupt maintenance of AMPA receptors, irreversibly disrupting numerous forms of learning and memory that have been maintained for weeks. Delay eyeblink conditioning (EBC) is an established model for the assessment of cerebellar learning; here, we show that PKC-ζ and PKM-ζ are highly expressed in the cerebellar cortex, with highest expression found in Purkinje cell (PC) nuclei. Despite being highly expressed in the cerebellar cortex, no studies have examined how regulation of cerebellar PKM-ζ may affect cerebellar-dependent learning and memory. Given its disruption of learning in other brain structures, we hypothesized that ZIP would also disrupt delay EBC. We have shown that infusion of ZIP into the lobulus simplex of the rat cerebellar cortex can indeed significantly disrupt delay EBC. PMID:26949968

  13. Investigating the role of hippocampal BDNF in anxiety vulnerability using classical eyeblink conditioning

    Directory of Open Access Journals (Sweden)

    Kellie L Janke

    2015-07-01

    Full Text Available Dysregulation of brain-derived neurotrophic factor (BDNF, behavioral inhibition temperament (BI and small hippocampal volume have been linked to anxiety disorders. Individuals with BI show facilitated acquisition of the classically conditioned eyeblink response (CCER as compared to non-BI individuals, and a similar pattern is seen in an animal model of BI, the Wistar-Kyoto (WKY rat. The present study examined the role of hippocampal BDNF in the facilitated delay CCER of WKY rats. Consistent with earlier work, acquisition was facilitated in WKY rats compared to the SD rats. Facilitated acquisition was associated with increased BDNF, TrkB, and Arc mRNA in the dentate gyrus of SD rats, but learning-induced increases in BDNF and Arc mRNA were significantly smaller in WKY rats. To determine if reduced hippocampal BDNF in WKY rats was a contributing factor for their facilitated CCER, BDNF or saline infusions were given bilaterally into the dentate gyrus region one hour prior to training. BDNF infusion did not alter the acquisition of SD rats, but significantly dampened the acquisition of CCER in the WKY rats, such that acquisition was similar to SD rats. Together, these results suggest that inherent differences in the BDNF system play a critical role in the facilitated associative learning exhibited by WKY rats, and potentially individuals with BI. Facilitated associative learning may represent a vulnerability factor in the development of anxiety disorders.

  14. Enhanced conditioned eyeblink response acquisition and proactive interference in anxiety vulnerable individuals

    Directory of Open Access Journals (Sweden)

    Jacqueline L Holloway

    2012-11-01

    Full Text Available In classical conditioning, proactive interference may arise from experience with the conditioned stimulus (CS, the unconditional stimulus (US, or both, prior to their paired presentations. Interest in the application of proactive interference has extended to clinical populations as either a risk factor for disorders or as a secondary sign. Although the current literature is dense with comparisons of stimulus pre-exposure effects in animals, such comparisons are lacking in human subjects. As such, interpretation of proactive interference over studies as well as its generalization and utility in clinical research is limited. The present study was designed to assess eyeblink response acquisition after equal numbers of CS, US, and explicitly unpaired CS and US pre-exposures, as well as to evaluate how anxiety vulnerability might modulate proactive interference. In the current study, anxiety vulnerability was assessed using the State/Trait Anxiety Inventories as well as the adult and retrospective measures of behavioural inhibition (AMBI and RMBI, respectively. Participants were exposed to 1 of 4 possible pre-exposure contingencies: 30 CS, 30 US, 30 CS and 30 US explicitly unpaired pre-exposures, or context pre-exposure, immediately prior to standard delay training. Robust proactive interference was evident in all pre-exposure groups relative to context pre-exposure, independent of anxiety classification, with CR acquisition attenuated at similar rates. In addition, trait anxious individuals were found to have enhanced overall acquisition as well as greater proactive interference relative to non-vulnerable individuals. The findings suggest that anxiety vulnerable individuals learn implicit associations faster, an effect which persists after the introduction of new stimulus contingencies. This effect is not due to enhanced sensitivity to the US. Such differences would have implications for the development of anxiety psychopathology within a learning

  15. Enhanced Eyeblink Conditioning in Behaviorally Inhibited Individuals is Disrupted by Proactive Interference Following US Alone Pre-exposures.

    Science.gov (United States)

    Allen, Michael Todd; Miller, Daniel P

    2016-01-01

    Anxiety vulnerable individuals exhibit enhanced acquisition of conditioned eyeblinks as well as enhanced proactive interference from conditioned stimulus (CS) or unconditioned stimulus (US) alone pre-exposures (Holloway et al., 2012). US alone pre-exposures disrupt subsequent conditioned response (CR) acquisition to CS-US paired trials as compared to context pre-exposure controls. While Holloway et al. (2012) reported enhanced acquisition in high trait anxiety individuals in the context condition, anxiety vulnerability effects were not reported for the US alone pre-exposure group. It appears from the published data that there were no differences between high and low anxiety individuals in the US alone condition. In the work reported here, we sought to extend the findings of enhanced proactive interference with US alone pre-exposures to determine if the enhanced conditioning was disrupted by proactive interference procedures. We also were interested in the spontaneous eyeblinks during the pre-exposure phase of training. We categorized individuals as anxiety vulnerability or non-vulnerable individuals based scores on the Adult Measure of Behavioral Inhibition (AMBI). Sixty-six participants received 60 trials consisting of 30 US alone or context alone pre-exposures followed by 30 CS-US trials. US alone pre-exposures not only disrupted CR acquisition overall, but behaviorally inhibited (BI) individuals exhibited enhanced proactive interference as compared to non-inhibited (NI) individuals. In addition, US alone pre-exposures disrupted the enhanced acquisition observed in BI individuals as compared to NI individuals following context alone pre-exposures. Differences were also found in rates of spontaneous eyeblinks between BI and NI individuals during context pre-exposure. Our findings will be discussed in the light of the neural substrates of eyeblink conditioning as well as possible factors such as hypervigilance in the amygdala and hippocampal systems, and possible

  16. Reevaluation of the role of parallel fiber synapses in delay eyeblink conditioning in mice using Cbln1 as a tool

    OpenAIRE

    Kyoichi eEmi; Wataru eKakegawa; Eriko eMiura; Aya eIto-Ishida; Kazuhisa eKohda; Michisuke eYuzaki

    2013-01-01

    The delay eyeblink conditioning (EBC) is a cerebellum-dependent type of associative motor learning. However, the exact roles played by the various cerebellar synapses, as well as the underlying molecular mechanisms, remain to be determined. It is also unclear whether long-term potentiation (LTP) or long-term depression (LTD) at parallel fiber (PF)–Purkinje cell synapses is involved in EBC. In this study, to clarify the role of PF synapses in the delay EBC, we used mice in which a gene encodin...

  17. Effects of OEF/OIF-Related Physical and Emotional Co-Morbidities on Associative Learning: Concurrent Delay and Trace Eyeblink Classical Conditioning

    Directory of Open Access Journals (Sweden)

    Regina E. McGlinchey

    2014-03-01

    Full Text Available This study examined the performance of veterans and active duty personnel who served in Operation Enduring Freedom and/or Operation Iraqi Freedom (OEF/OIF on a basic associative learning task. Eighty-eight individuals participated in this study. All received a comprehensive clinical evaluation to determine the presence and severity of posttraumatic stress disorder (PTSD and traumatic brain injury (TBI. The eyeblink conditioning task was composed of randomly intermixed delay and trace conditioned stimulus (CS and unconditioned stimulus (US pairs (acquisition followed by a series of CS only trials (extinction. Results revealed that those with a clinical diagnosis of PTSD or a diagnosis of PTSD with comorbid mTBI acquired delay and trace conditioned responses (CRs to levels and at rates similar to a deployed control group, thus suggesting intact basic associative learning. Differential extinction impairment was observed in the two clinical groups. Acquisition of CRs for both delay and trace conditioning, as well as extinction of trace CRs, was associated with alcoholic behavior across all participants. These findings help characterize the learning and memory function of individuals with PTSD and mTBI from OEF/OIF and raise the alarming possibility that the use of alcohol in this group may lead to more significant cognitive dysfunction.

  18. Effects of OEF/OIF-related physical and emotional co-morbidities on associative learning: concurrent delay and trace eyeblink classical conditioning.

    Science.gov (United States)

    McGlinchey, Regina E; Fortier, Catherine B; Venne, Jonathan R; Maksimovskiy, Arkadiy L; Milberg, William P

    2014-03-12

    This study examined the performance of veterans and active duty personnel who served in Operation Enduring Freedom and/or Operation Iraqi Freedom (OEF/OIF) on a basic associative learning task. Eighty-eight individuals participated in this study. All received a comprehensive clinical evaluation to determine the presence and severity of posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI). The eyeblink conditioning task was composed of randomly intermixed delay and trace conditioned stimulus (CS) and unconditioned stimulus (US) pairs (acquisition) followed by a series of CS only trials (extinction). Results revealed that those with a clinical diagnosis of PTSD or a diagnosis of PTSD with comorbid mTBI acquired delay and trace conditioned responses (CRs) to levels and at rates similar to a deployed control group, thus suggesting intact basic associative learning. Differential extinction impairment was observed in the two clinical groups. Acquisition of CRs for both delay and trace conditioning, as well as extinction of trace CRs, was associated with alcoholic behavior across all participants. These findings help characterize the learning and memory function of individuals with PTSD and mTBI from OEF/OIF and raise the alarming possibility that the use of alcohol in this group may lead to more significant cognitive dysfunction.

  19. Transfer of classical eyeblink conditioning with electrical stimulation of mPFC or tone as conditioned stimulus in guinea pigs.

    Science.gov (United States)

    Yao, Juan; Wu, Guang-Yan; Liu, Guo-Long; Liu, Shu-Lei; Yang, Yi; Wu, Bing; Li, Xuan; Feng, Hua; Sui, Jian-Feng

    2014-11-01

    Learning with a stimulus from one sensory modality can facilitate subsequent learning with a new stimulus from a different sensory modality. To date, the characteristics and mechanism of this phenomenon named transfer effect still remain ambiguous. Our previous work showed that electrical stimulation of medial prefrontal cortex (mPFC) as a conditioned stimulus (CS) could successfully establish classical eyeblink conditioning (EBC). The present study aimed to (1) observe whether transfer of EBC learning would occur when CSs shift between central (mPFC electrical stimulation as a CS, mPFC-CS) and peripheral (tone as a CS, tone CS); (2) compare the difference in transfer effect between the two paradigms, delay EBC (DEBC) and trace EBC (TEBC). A total of 8 groups of guinea pigs were tested in the study, including 4 experimental groups and 4 control groups. Firstly, the experimental groups accepted central (or peripheral) CS paired with corneal airpuff unconditioned stimulus (US); then, CS shifted to the peripheral (or central) and paired with US. The control groups accepted corresponding central (or peripheral) CS and pseudo-paired with US, and then shifted CS from central (or peripheral) to peripheral (or central) and paired with US. The results showed that the acquisition rates of EBC were higher in experimental groups than in control groups after CS switching from central to peripheral or vice versa, and the CR acquisition rate was remarkably higher in DEBC than in TEBC in both transfer ways. The results indicate that EBC transfer can occur between learning established with mPFC-CS and tone CS. Memory of CS-US association for delay paradigm was less disturbed by the sudden switch of CS than for trace paradigm. This study provides new insight into neural mechanisms underlying conditioned reflex as well as the role of mPFC.

  20. Avoidance Prone Individuals Self Reporting Behavioral Inhibition Exhibit Facilitated Acquisition and Altered Extinction of Conditioned Eyeblinks With Partial Reinforcement Schedules

    Directory of Open Access Journals (Sweden)

    Michael Todd Allen

    2014-10-01

    Full Text Available Avoidance in the face of novel situations or uncertainty is a prime feature of behavioral inhibition which has been put forth as a risk factor for the development of anxiety disorders. Recent work has found that behaviorally inhibited individuals acquire conditioned eyeblinks faster than non-inhibited individuals in omission and yoked paradigms in which the predictive relationship between the conditioned stimulus (CS and unconditional stimulus (US is less than optimal as compared to standard training with CS-US paired trials (Holloway et al., 2014. In the current study, we tested explicitly partial schedules in which half the trials were CS alone or US alone trials in addition to the standard CS-US paired trials. One hundred and forty nine college-aged undergraduates participated in the study. All participants completed the Adult Measure of Behavioral Inhibition (i.e., AMBI which was used to group participants as behaviorally inhibited and non-inhibited. Eyeblink conditioning consisted of 3 US alone trials, 60 acquisition trials, and 20 CS-alone extinction trials presented in one session. Conditioning stimuli were a 500 ms tone conditioned stimulus (CS and a 50-ms air puff unconditional stimulus (US. Behaviorally inhibited individuals receiving 50% partial reinforcement with CS alone or US alone trials produced facilitated acquisition as compared to non-inhibited individuals. A partial reinforcement extinction effect was evident with CS alone trials in behaviorally inhibited but not non-inhibited individuals. These current findings indicate that avoidance prone individuals self-reporting behavioral inhibition over-learn an association and are slow to extinguish conditioned responses when there is some level of uncertainty between paired trials and CS or US alone presentations.

  1. Avoidance prone individuals self reporting behavioral inhibition exhibit facilitated acquisition and altered extinction of conditioned eyeblinks with partial reinforcement schedules.

    Science.gov (United States)

    Allen, Michael Todd; Myers, Catherine E; Servatius, Richard J

    2014-01-01

    Avoidance in the face of novel situations or uncertainty is a prime feature of behavioral inhibition which has been put forth as a risk factor for the development of anxiety disorders. Recent work has found that behaviorally inhibited (BI) individuals acquire conditioned eyeblinks faster than non-inhibited (NI) individuals in omission and yoked paradigms in which the predictive relationship between the conditioned stimulus (CS) and unconditional stimulus (US) is less than optimal as compared to standard training with CS-US paired trials (Holloway et al., 2014). In the current study, we tested explicitly partial schedules in which half the trials were CS alone or US alone trials in addition to the standard CS-US paired trials. One hundred and forty nine college-aged undergraduates participated in the study. All participants completed the Adult Measure of Behavioral Inhibition (i.e., AMBI) which was used to group participants as BI and NI. Eyeblink conditioning consisted of three US alone trials, 60 acquisition trials, and 20 CS-alone extinction trials presented in one session. Conditioning stimuli were a 500 ms tone CS and a 50-ms air puff US. Behaviorally inhibited individuals receiving 50% partial reinforcement with CS alone or US alone trials produced facilitated acquisition as compared to NI individuals. A partial reinforcement extinction effect (PREE) was evident with CS alone trials in BI but not NI individuals. These current findings indicate that avoidance prone individuals self-reporting behavioral inhibition over-learn an association and are slow to extinguish conditioned responses (CRs) when there is some level of uncertainty between paired trials and CS or US alone presentations.

  2. Eyeblink classical conditioning and interpositus nucleus activity are disrupted in adult rats exposed to ethanol as neonates.

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    Green, John T; Johnson, Timothy B; Goodlett, Charles R; Steinmetz, Joseph E

    2002-01-01

    Neonatal exposure to ethanol in rats, during the period of brain development comparable to that of the human third trimester, produces significant, dose-dependent cell loss in the cerebellum and deficits in coordinated motor performance. These rats are also impaired in eyeblink conditioning as weanlings and as adults. The current study examined single-unit neural activity in the interpositus nucleus of the cerebellum in adults following neonatal binge ethanol exposure. Group Ethanol received alcohol doses of 5.25 g/kg/day on postnatal days 4-9. Group Sham Intubated underwent acute intragastric intubation on postnatal days 4-9 but did not receive any infusions. Group Unintubated Control (from separate litters) did not receive any intubations. When rats were 3-7 mo old, pairs of extracellular microelectrodes were implanted in the region of the interpositus nucleus. Beginning 1 wk later, the rats were given either 100 paired or 190 unpaired trials per day for 10 d followed by 4 d of 100 conditioned stimulus (CS)-alone trials per day. As in our previous study, conditioned response acquisition in Group Ethanol rats was impaired. In addition, by session 5 of paired acquisition, Group Sham Intubated and Group Unintubated Control showed significant increases in interpositus nucleus activity, relative to baseline, in the CS-unconditioned stimulus interval. In contrast, Group Ethanol failed to show significant changes in interpositus nucleus activity until later in training. These results indicate that the disruption in eyeblink conditioning after early exposure to ethanol is reflected in alterations in interpositus nucleus activity.

  3. Eyeblink Classical Conditioning and Interpositus Nucleus Activity Are Disrupted in Adult Rats Exposed to Ethanol as Neonates

    Science.gov (United States)

    Green, John T.; Johnson, Timothy B.; Goodlett, Charles R.; Steinmetz, Joseph E.

    2002-01-01

    Neonatal exposure to ethanol in rats, during the period of brain development comparable to that of the human third trimester, produces significant, dose-dependent cell loss in the cerebellum and deficits in coordinated motor performance. These rats are also impaired in eyeblink conditioning as weanlings and as adults. The current study examined single-unit neural activity in the interpositus nucleus of the cerebellum in adults following neonatal binge ethanol exposure. Group Ethanol received alcohol doses of 5.25 g/kg/day on postnatal days 4–9. Group Sham Intubated underwent acute intragastric intubation on postnatal days 4–9 but did not receive any infusions. Group Unintubated Control (from separate litters) did not receive any intubations. When rats were 3–7 mo old, pairs of extracellular microelectrodes were implanted in the region of the interpositus nucleus. Beginning 1 wk later, the rats were given either 100 paired or 190 unpaired trials per day for 10 d followed by 4 d of 100 conditioned stimulus (CS)-alone trials per day. As in our previous study, conditioned response acquisition in Group Ethanol rats was impaired. In addition, by session 5 of paired acquisition, Group Sham Intubated and Group Unintubated Control showed significant increases in interpositus nucleus activity, relative to baseline, in the CS–unconditioned stimulus interval. In contrast, Group Ethanol failed to show significant changes in interpositus nucleus activity until later in training. These results indicate that the disruption in eyeblink conditioning after early exposure to ethanol is reflected in alterations in interpositus nucleus activity. PMID:12359839

  4. Effect of varying the intensity and train frequency of forelimb and cerebellar mossy fiber conditioned stimuli on the latency of conditioned eye-blink responses in decerebrate ferrets.

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    Svensson, P; Ivarsson, M; Hesslow, G

    1997-01-01

    To study the role of the mossy fiber afferents to the cerebellum in classical eye-blink conditioning, in particular the timing of the conditioned responses, we compared the effects of varying a peripheral conditioned stimulus with the effects of corresponding variations of direct stimulation of the mossy fibers. In one set of experiments, decerebrate ferrets were trained in a Pavlovian eye-blink conditioning paradigm with electrical forelimb train stimulation as conditioned stimulus and electrical periorbital stimulation as the unconditioned stimulus. When stable conditioning had been achieved, the effect of increasing the intensity or frequency of the forelimb stimulation was tested. By increasing the intensity from 1 to 2 mA, or the train frequency from 50 to 100 Hz, an immediate decrease was induced in both the onset latency and the latency to peak of the conditioned response. If the conditioned stimulus intensity/frequency was maintained at the higher level, the response latencies gradually returned to preshift values. In a second set of experiments, the forelimb stimulation was replaced by direct train stimulation of the middle cerebellar peduncle as conditioned stimulus. Varying the frequency of the stimulus train between 50 and 100 Hz had effects that were almost identical to those obtained when using a forelimb conditioned stimulus. The functional meaning of the latency effect is discussed. It is also suggested that the results support the view that the conditioned stimulus is transmitted through the mossy fibers and that the mechanism for timing the conditioned response is situated in the cerebellum.

  5. Harnessing the power of theta: natural manipulations of cognitive performance during hippocampal theta-contingent eyeblink conditioning

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    Hoffmann, Loren C.; Cicchese, Joseph J.; Berry, Stephen D.

    2015-01-01

    Neurobiological oscillations are regarded as essential to normal information processing, including coordination and timing of cells and assemblies within structures as well as in long feedback loops of distributed neural systems. The hippocampal theta rhythm is a 3–12 Hz oscillatory potential observed during cognitive processes ranging from spatial navigation to associative learning. The lower range, 3–7 Hz, can occur during immobility and depends upon the integrity of cholinergic forebrain systems. Several studies have shown that the amount of pre-training theta in the rabbit strongly predicts the acquisition rate of classical eyeblink conditioning and that impairment of this system substantially slows the rate of learning. Our lab has used a brain-computer interface (BCI) that delivers eyeblink conditioning trials contingent upon the explicit presence or absence of hippocampal theta. A behavioral benefit of theta-contingent training has been demonstrated in both delay and trace forms of the paradigm with a two- to four-fold increase in learning speed. This behavioral effect is accompanied by enhanced amplitude and synchrony of hippocampal local field potential (LFP)s, multi-unit excitation, and single-unit response patterns that depend on theta state. Additionally, training in the presence of hippocampal theta has led to increases in the salience of tone-induced unit firing patterns in the medial prefrontal cortex, followed by persistent multi-unit activity during the trace interval. In cerebellum, rhythmicity and precise synchrony of stimulus time-locked LFPs with those of hippocampus occur preferentially under the theta condition. Here we review these findings, integrate them into current models of hippocampal-dependent learning and suggest how improvement in our understanding of neurobiological oscillations is critical for theories of medial temporal lobe processes underlying intact and pathological learning. PMID:25918501

  6. Involvement of the ipsilateral and contralateral cerebellum in the acquisition of unilateral classical eyeblink conditioning in guinea pigs

    Institute of Scientific and Technical Information of China (English)

    Bo HU; Xi LIN; Lushuai HUANG; Li YANG; Hua FENG; Jianfeng SUI

    2009-01-01

    Aim:The aim of this study was to evaluate the relative contributions of the ipsilateral and contralateral cerebellum to the acquisition of unilateral classical eyeblink conditioning (EBCC).Methods: The unilateral EBCC was achieved using a binaural tone conditioned stimulus (CS) paired with a left airpuff unconditioned stimulus (US).A high-resolution potentiometer was used to monitor eyeblink responses.Guinea pigs received one CS-US session followed by three CS-US sessions (sessions 2 to 4),during which microinjections of muscimol,a GABAA receptor agonist,were performed to reversibly inactivate the cerebellum unilaterally prior to training.To test whether any learning had occurred during these inactivation sessions,training was continued for six more CS-US sessions (sessions 5 to 10) without any inactivation.Results: Animals with inactivation of the left cerebellum had no signs of left conditioned response (CR) during sessions 2 to 4,and their CR acquisition during sessions 5 to 10 was not distinguishable from that of control animals during sessions 2 to 7.In contrast,animals with inactivation of the right cerebellum acquired left CRs during sessions 2 to 4,although their CR acquisition was significantly retarded during session 2.In addition,microinjections of muscimol into the right cerebellum did not affect left neuro-behavioral activity.Finally,microinjections of muscimol into either the left or the right cerebellum did not affect the performance of tone-airpuff evoked unconditioned response (UR).Conclusion: In contrast to the essential role of the ipsilateral cerebellum,the contralateral cerebellum is potentially involved in the acquisition of unilateral EBCC during the early stage of training.

  7. Autonomic and eyeblink conditioning are closely related to contingency awareness: reply to Wiens and Ohman (2002) and Manns et al. (2002).

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    Shanks, David R; Lovibond, Peter F

    2002-01-01

    S. Wiens and A. Ohman (2002) disputed the conclusion that Pavlovian conditioning is strongly related to contingency awareness (P. F. Lovibond & D. R. Shanks, 2002) on the basis that an inappropriate definition of awareness was used. J. R. Manns, R. E. Clark, and L. R. Squire (2002) contended that delay eyeblink conditioning is independent of awareness. The authors of the present article consider these arguments, highlight several problems in the new studies described by the commentators, and conclude that there is still little evidence for unconscious conditioning in either subliminal autonomic conditioning or eyeblink conditioning. The most parsimonious account of existing data is that a single learning process gives rise to both awareness and conditioned responding. Further progress in evaluating the possibility of unconscious conditioning would be facilitated by the development of more completely specified and testable dual-process models.

  8. Autism and classical eyeblink conditioning: Performance changes of the conditioned response related to autism spectrum disorder diagnosis

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    John P Welsh

    2016-08-01

    Full Text Available Changes in the timing performance of conditioned responses (CRs acquired during trace and delay eyeblink conditioning (EBC are presented for diagnostic subgroups of children having autism spectrum disorder (ASD aged 6-15 years. Children diagnosed with autistic disorder (AD were analyzed separately from children diagnosed with either Asperger’s syndrome or Pervasive-developmental disorder not-otherwise-specified (Asp/PDD and compared to an age- and IQ-matched group of children that were typically developing (TD. Within-subject and between-groups contrasts in CR performance on sequential exposure to trace and delay EBC were analyzed to determine whether any differences would expose underlying functional heterogeneities of the cerebral and cerebellar systems in ASD subgroups. The EBC parameters measured were percentage CRs, CR onset latency, and CR peak latency. Neither AD nor Asp/PDD groups were impaired in CR acquisition during trace or delay EBC. AD and Asp/PDD both altered CR timing, but not always in the same way. Although the AD group showed normal CR timing during trace EBC, the Asp/PDD group showed a significant 27 and 28 ms increase in CR onset and peak latency, respectively, during trace EBC. In contrast, the direction of the timing change was opposite during delay EBC, during which the Asp/PDD group showed a significant 29 ms decrease in CR onset latency and the AD group showed a larger 77 ms decrease in CR onset latency. Only the AD group showed a decrease in CR peak latency during delay EBC, demonstrating another difference between AD and Asp/PDD. The difference in CR onset latency during delay EBC for both AD and Asp/PDD was due to an abnormal prevalence of early onset CRs that were intermixed with CRs having normal timing, as observed both in CR onset histograms and mean CR waveforms. In conclusion, significant heterogeneity in EBC performance was apparent within diagnostic groups, and this may indicate that EBC performance can

  9. Reevaluation of the role of parallel fiber synapses in delay eyeblink conditioning in mice using Cbln1 as a tool.

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    Emi, Kyoichi; Kakegawa, Wataru; Miura, Eriko; Ito-Ishida, Aya; Kohda, Kazuhisa; Yuzaki, Michisuke

    2013-01-01

    The delay eyeblink conditioning (EBC) is a cerebellum-dependent type of associative motor learning. However, the exact roles played by the various cerebellar synapses, as well as the underlying molecular mechanisms, remain to be determined. It is also unclear whether long-term potentiation (LTP) or long-term depression (LTD) at parallel fiber (PF)-Purkinje cell (PC) synapses is involved in EBC. In this study, to clarify the role of PF synapses in the delay EBC, we used mice in which a gene encoding Cbln1 was disrupted (cbln1(-/-) mice), which display severe reduction of PF-PC synapses. We showed that delay EBC was impaired in cbln1(-/-) mice. Although PF-LTD was impaired, PF-LTP was normally induced in cbln1(-/-) mice. A single recombinant Cbln1 injection to the cerebellar cortex in vivo completely, though transiently, restored the morphology and function of PF-PC synapses and delay EBC in cbln1(-/-) mice. Interestingly, the cbln1(-/-) mice retained the memory for at least 30 days, after the Cbln1 injection's effect on PF synapses had abated. Furthermore, delay EBC memory could be extinguished even after the Cbln1 injection's effect were lost. These results indicate that intact PF-PC synapses and PF-LTD, not PF-LTP, are necessary to acquire delay EBC in mice. In contrast, extracerebellar structures or remaining PF-PC synapses in cbln1(-/-) mice may be sufficient for the expression, maintenance, and extinction of its memory trace.

  10. New insights into the nature of cerebellar-dependent eyeblink conditioning deficits in schizophrenia: A hierarchical linear modeling approach

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    Amanda R Bolbecker

    2016-01-01

    Full Text Available Evidence of cerebellar dysfunction in schizophrenia has mounted over the past several decades, emerging from neuroimaging, neuropathological, and behavioral studies. Consistent with these findings, cerebellar-dependent delay eyeblink conditioning (dEBC deficits have been identified in schizophrenia. While repeated measures analysis of variance (ANOVA is traditionally used to analyze dEBC data, hierarchical linear modeling (HLM more reliably describes change over time by accounting for the dependence in repeated measures data. This analysis approach is well suited to dEBC data analysis because it has less restrictive assumptions and allows unequal variances. The current study examined dEBC measured with electromyography in a single-cue tone paradigm in an age-matched sample of schizophrenia participants and healthy controls (N=56 per group using HLM. Subjects participated in 90 trials (10 blocks of dEBC, during which a 400 ms tone co-terminated with a 50 ms air puff delivered to the left eye. Each block also contained 1 tone-alone trial. The resulting block averages of dEBC data were fitted to a 3-parameter logistic model in HLM, revealing significant differences between schizophrenia and control groups on asymptote and inflection point, but not slope. These findings suggest that while the learning rate is not significantly different compared to controls, associative learning begins to level off later and a lower ultimate level of associative learning is achieved in schizophrenia. Given the large sample size in the present study, HLM may provide a more nuanced and definitive analysis of differences between schizophrenia and controls on dEBC.

  11. Reevaluation of the role of parallel fiber synapses in delay eyeblink conditioning in mice using Cbln1 as a tool

    Directory of Open Access Journals (Sweden)

    Kyoichi eEmi

    2013-11-01

    Full Text Available The delay eyeblink conditioning (EBC is a cerebellum-dependent type of associative motor learning. However, the exact roles played by the various cerebellar synapses, as well as the underlying molecular mechanisms, remain to be determined. It is also unclear whether long-term potentiation (LTP or long-term depression (LTD at parallel fiber (PF–Purkinje cell synapses is involved in EBC. In this study, to clarify the role of PF synapses in the delay EBC, we used mice in which a gene encoding Cbln1 was disrupted (cbln1–/– mice, which display severe reduction of PF–Purkinje cell synapses. We showed that delay EBC was impaired in cbln1–/– mice. Although PF-LTD was impaired, PF-LTP was normally induced in cbln1–/– mice. A single recombinant Cbln1 injection to the cerebellar cortex in vivo completely, though transiently, restored the morphology and function of PF–Purkinje cell synapses and delay EBC in cbln1–/– mice. Interestingly, the cbln1–/– mice retained the memory for at least 30 d, after the Cbln1 injection’s effect on PF synapses had abated. Furthermore, delay EBC memory could be extinguished even after the Cbln1 injection’s effect were lost. These results indicate that intact PF–Purkinje cell synapses and PF-LTD, not PF-LTP, are necessary to acquire delay EBC in mice. In contrast, extracerebellar structures or remaining PF–Purkinje cell synapses in cbln1–/– mice may be sufficient for the expression, maintenance, and extinction of its memory trace.

  12. New Insights into the Nature of Cerebellar-Dependent Eyeblink Conditioning Deficits in Schizophrenia: A Hierarchical Linear Modeling Approach.

    Science.gov (United States)

    Bolbecker, Amanda R; Petersen, Isaac T; Kent, Jerillyn S; Howell, Josselyn M; O'Donnell, Brian F; Hetrick, William P

    2016-01-01

    Evidence of cerebellar dysfunction in schizophrenia has mounted over the past several decades, emerging from neuroimaging, neuropathological, and behavioral studies. Consistent with these findings, cerebellar-dependent delay eyeblink conditioning (dEBC) deficits have been identified in schizophrenia. While repeated-measures analysis of variance is traditionally used to analyze dEBC data, hierarchical linear modeling (HLM) more reliably describes change over time by accounting for the dependence in repeated-measures data. This analysis approach is well suited to dEBC data analysis because it has less restrictive assumptions and allows unequal variances. The current study examined dEBC measured with electromyography in a single-cue tone paradigm in an age-matched sample of schizophrenia participants and healthy controls (N = 56 per group) using HLM. Subjects participated in 90 trials (10 blocks) of dEBC, during which a 400 ms tone co-terminated with a 50 ms air puff delivered to the left eye. Each block also contained 1 tone-alone trial. The resulting block averages of dEBC data were fitted to a three-parameter logistic model in HLM, revealing significant differences between schizophrenia and control groups on asymptote and inflection point, but not slope. These findings suggest that while the learning rate is not significantly different compared to controls, associative learning begins to level off later and a lower ultimate level of associative learning is achieved in schizophrenia. Given the large sample size in the present study, HLM may provide a more nuanced and definitive analysis of differences between schizophrenia and controls on dEBC.

  13. Children with specific language impairment are not impaired in the acquisition and retention of Pavlovian delay and trace conditioning of the eyeblink response.

    Science.gov (United States)

    Hardiman, Mervyn J; Hsu, Hsin-jen; Bishop, Dorothy V M

    2013-12-01

    Three converging lines of evidence have suggested that cerebellar abnormality is implicated in developmental language and literacy problems. First, some brain imaging studies have linked abnormalities in cerebellar grey matter to dyslexia and specific language impairment (SLI). Second, theoretical accounts of both dyslexia and SLI have postulated impairments of procedural learning and automatisation of skills, functions that are known to be mediated by the cerebellum. Third, motor learning has been shown to be abnormal in some studies of both disorders. We assessed the integrity of face related regions of the cerebellum using Pavlovian eyeblink conditioning in 7-11year-old children with SLI. We found no relationship between oral language skills or literacy skills with either delay or trace conditioning in the children. We conclude that this elementary form of associative learning is intact in children with impaired language or literacy development. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  14. Pronounced reduction of acquisition of conditioned eyeblink responses in young adults with focal cerebellar lesions impedes conclusions on the role of the cerebellum in extinction and savings.

    Science.gov (United States)

    Ernst, T M; Beyer, L; Mueller, O M; Göricke, S; Ladd, M E; Gerwig, M; Timmann, D

    2016-05-01

    Human cerebellar lesion studies provide good evidence that the cerebellum contributes to the acquisition of classically conditioned eyeblink responses (CRs). As yet, only one study used more advanced methods of lesion-symptom (or lesion-behavior) mapping to investigate which cerebellar areas are involved in CR acquisition in humans. Likewise, comparatively few studies investigated the contribution of the human cerebellum to CR extinction and savings. In this present study, young adults with focal cerebellar disease were tested. A subset of participants was expected to acquire enough conditioned responses to allow the investigation of extinction and saving effects. 19 participants with chronic surgical lesions of the cerebellum and 19 matched control subjects were tested. In all cerebellar subjects benign tumors of the cerebellum had been surgically removed. Eyeblink conditioning was performed using a standard short delay protocol. An initial unpaired control phase was followed by an acquisition phase, an extinction phase and a subsequent reacquisition phase. Structural 3T magnetic resonance images of the brain were acquired on the day of testing. Cerebellar lesions were normalized using methods optimized for the cerebellum. Subtraction analysis and Liebermeister tests were used to perform lesion-symptom mapping. As expected, CR acquisition was significantly reduced in cerebellar subjects compared to controls. Reduced CR acquisition was significantly more likely in participants with lesions of lobule VI and Crus I extending into Crus II (pacquisition, extinction and savings within the normal range; and a larger group (n=14) which did not show acquisition. In the latter, no conclusions on extinction or savings could be drawn. Previous findings were confirmed that circumscribed areas in lobule VI and Crus I are of major importance in CR acquisition. In addition, the present data suggest that if the critical regions of the cerebellar cortex are lesioned, the ability to

  15. Cleavage of proBDNF to BDNF by a tolloid-like metalloproteinase is required for acquisition of in vitro eyeblink classical conditioning.

    Science.gov (United States)

    Keifer, Joyce; Sabirzhanov, Boris E; Zheng, Zhaoqing; Li, Wei; Clark, Timothy G

    2009-11-25

    The tolloid/bone morphogenetic protein-1 family of metalloproteinases have an important role in the regulation of embryonic pattern formation and tissue morphogenesis. Studies suggest that they participate in mechanisms of synaptic plasticity in adults, but very little is known about their function. Recently, we isolated a reptilian ortholog of the tolloid gene family designated turtle tolloid-like gene (tTll). Here, we examined the role of tTLL in an in vitro model of eyeblink classical conditioning using an isolated brainstem preparation to assess its role in synaptic plasticity during conditioning. Analysis by real-time reverse transcription-PCR shows that an extracellularly secreted form of tTLL, tTLLs, is transiently expressed in the early stages of conditioning during conditioned response acquisition, whereas a cytosolic form, tTLLc, is not. Short interfering RNA (siRNA)-directed gene knockdown and rescue of tTLL expression demonstrate that it is required for conditioning. Significantly, we show that tTLLs cleaves the precursor proBDNF into mature BDNF in cleavage assay studies, and application of recombinant tTLLs protein alone to preparations results in induction of mature BDNF expression. The mature form of BDNF is minimally expressed in preparations treated with anti-tTLL siRNA, and the synaptic incorporation of both GluR1- and GluR4-containing AMPA receptors is significantly reduced, resulting in suppression of conditioning. This is the first study to demonstrate that expression of an extracellularly secreted tolloid-like metalloproteinase is regulated in the early stages of classical conditioning and functions in the conversion of proBDNF to mature BDNF. The mature form of BDNF is required for synaptic delivery of AMPA receptors and acquisition of conditioned responses.

  16. Comparison research of the classical eyeblink conditioning in guinea pig induced by visual and auditory circle%视觉与听觉通路诱导的豚鼠眨眼条件反射的比较研究

    Institute of Scientific and Technical Information of China (English)

    范郑丽; 隋建峰; 李蕊; 万子兵; 赵红梅

    2009-01-01

    目的 以眼肌电记录法分别记录豚鼠以声音和光信号作为条件刺激(CS)的眨眼条件反射(CR),分析并比较其习得规律.方法 采用金属电极埋植技术及简易"随动"气流给气刺激装置,分别以声音和光信号作为条件刺激(CS),以气流作为非条件刺激(US),以眼肌电信号判断其眨眼行为,在清醒无制动的豚鼠上进行经典眨眼条件反射的训练.结果 在豚鼠内眦采集并记录到眨眼肌电信号显示,声音条件刺激组在第1天、第4天、第7天、第10天的CR习得率分别为(5.0±1.09)%、(31.0±2.09)%、(61.33±1.63)%、(82.33±1.63)%,而光条件刺激组在第1天、第4天、第7天、第10天的CR习得率分别为(5.5±4.59)%、(4.33±3.14)%、(10.83±13.42)%、(3.83±1.33)%,2组CR习得率差异有显著性(P<0.05).结论 以声音作为条件刺激时豚鼠能够成功建立的眨眼条件反射,而以光作为条件刺激时眨眼条件反射的建立却非常困难.%Objective To record the classical eyeblink conditioning single,which the conditioned stimu-lus(CS) is tone or light, by the electromyographic (EMG) of musculi oculi recording. Methods Adopting metal electrode embedding technic and simple air puff stimulus facility ,tone or light as the conditioned stimulus(CS) was paired with air puff being unconditioned stimulus(US) to establish classical eyeblink conditioning of conscious un-fixed guinea pigs. The eyeblink behavior were evaluated through EMG of musculi oculi. Results The eyeblink EMG signal of musculi oculi showed: when the tone as the CS , the results indicated that the acquisition rate of the 1st,the 4th,the 7th,the 10th day were respectively (5.0±1.09)%,(31.0±2.09)%,(61.33±1.63)%,(82.33±1.63) % ; when the light as the CS , the results indicate that the acquisition rate of the 1 st, the 4th, the 7th, the 10th day were respectively (5.5±4.59) %, (4.33±3.14) %, (10.83±13.42)%, (3.83±1.33 ) %. Conclu-sion While CS is tone,classical eyeblink

  17. CS-dependent response probability in an auditory masked-detection task: considerations based on models of Pavlovian conditioning.

    Science.gov (United States)

    Mason, Christine R; Idrobo, Fabio; Early, Susan J; Abibi, Ayome; Zheng, Ling; Harrison, J Michael; Carney, Laurel H

    2003-05-01

    Experimental studies were performed using a Pavlovian-conditioned eyeblink response to measure detection of a variable-sound-level tone (T) in a fixed-sound-level masking noise (N) in rabbits. Results showed an increase in the asymptotic probability of conditioned responses (CRs) to the reinforced TN trials and a decrease in the asymptotic rate of eyeblink responses to the non-reinforced N presentations as a function of the sound level of the T. These observations are consistent with expected behaviour in an auditory masked detection task, but they are not consistent with predictions from a traditional application of the Rescorla-Wagner or Pearce models of associative learning. To implement these models, one typically considers only the actual stimuli and reinforcement on each trial. We found that by considering perceptual interactions and concepts from signal detection theory, these models could predict the CS dependence on the sound level of the T. In these alternative implementations, the animals response probabilities were used as a guide in making assumptions about the "effective stimuli".

  18. Detecting deception via eyeblink frequency modulation

    Directory of Open Access Journals (Sweden)

    Brandon S. Perelman

    2014-02-01

    Full Text Available To assess the efficacy of using eyeblink frequency modulation to detect deception about a third party, 32 participants were sent on a mission to deliver a package to an interviewer. 17 of the participants lied to the interviewer about the details of their mock mission and 15 responded truthfully. During the interview, eyeblink frequency data were collected via electromyography and recorded video. Liars displayed eyeblink frequency suppression while lying, while truth tellers exhibited an increase in eyeblink frequency during the mission relevant questioning period. The compensatory flurry of eyeblinks following deception observed in previous studies was absent in the present study. A discriminant function using eyeblink suppression to predict lying correctly classified 81.3% of cases, with a sensitivity of 88.2% and a specificity of 73.3%. This technique, yielding a reasonable sensitivity, shows promise for future testing as, unlike polygraph, it is compatible with distance technology.

  19. Acute Exposure to Stress Improves Performance in Trace Eyeblink Conditioning and Spatial Learning Tasks in Healthy Men

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    Duncko, Roman; Cornwell, Brian; Cui, Lihong; Merikangas, Kathleen R.; Grillon, Christian

    2007-01-01

    The present study investigated the effects of acute stress exposure on learning performance in humans using analogs of two paradigms frequently used in animals. Healthy male participants were exposed to the cold pressor test (CPT) procedure, i.e., insertion of the dominant hand into ice water for 60 sec. Following the CPT or the control procedure,…

  20. The nicotinic agonist RJR-2403 compensates the impairment of eyeblink conditioning produced by the noncompetitive NMDA-receptor antagonist MK-801.

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    Rodríguez-Moreno, Antonio; Carrión, Miriam; Delgado-García, José María

    2006-07-10

    The classical conditioning of eyelid responses using trace paradigms is a hippocampal-related model of associative learning, involving the activation of N-methyl-D-aspartate (NMDA) receptors. We have evaluated here the effects of NMDA-receptor blockage with the selective noncompetitive antagonist (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (dizocilpine, MK-801). Mice were implanted with stimulating electrodes on the supraorbitary nerve and with recording electrodes in the ipsilateral orbicularis oculi muscle. Animals were conditioned with a trace shock-SHOCK paradigm. MK-801-injected animals (0.02 mg/kg) seemed unable to acquire this type of associative learning task, but the latency and amplitude of their unconditioned eyelid responses was not affected by drug administration. The administration of the nicotinic agonist (E)-N-methyl-4-(3-pyridinyl)-3-buten-1-amine (RJR-2403; 2 mg/kg) was able to restore completely the acquisition of the conditioned response when administered both before and after MK-801. In vitro recordings of field excitatory postsynaptic potentials (fEPSPs) evoked in the hippocampal CA1 area by the electrical stimulation of the Schaffer collateral pathway indicates that RJR-2403 application to the bath enhance the release of glutamate by a presynaptic mechanism. These findings reveal that nicotinic acetylcholine receptors enhance glutamatergic transmission in hippocampal circuits involved in the acquisition of associative learning.

  1. A long-range, wide field-of-view infrared eyeblink detector.

    Science.gov (United States)

    Ryan, Steven B; Detweiler, Krystal L; Holland, Kyle H; Hord, Michael A; Bracha, Vlastislav

    2006-04-15

    Classical conditioning of the eyeblink response in the rabbit is one of the most advanced models of learning and memory in the mammalian brain. Successful use of the eyeblink conditioning paradigm requires precise measurements of the eyeblink response. One common technique of eyelid movement detection utilizes measurements of infrared (IR) light reflected from the surface of the eye. The performance of current IR sensors, however, is limited by their sensitivity to ambient infrared noise, by their small field-of-view and by short working distances. To address these limitations, we developed an IR eyeblink detector consisting of a pulsing (62.5 kHz) IR light emitting diode (LED) paired with a silicon IR photodiode and circuit that synchronously demodulates the recorded signal and rejects background IR noise. The working distance of the sensor exceeds 20 mm, and the field-of-view is larger than the area of a rabbit's eye. Due to its superior characteristics, the new sensor is ideally suited for both standard eyeblink conditioning and for studies that utilize IR-containing visual stimuli and/or that are conducted in an environment contaminated with IR noise.

  2. Mind Wandering in Text Comprehension under Dual-Task Conditions

    Directory of Open Access Journals (Sweden)

    Peter eDixon

    2013-10-01

    Full Text Available In two experiments, subjects responded to on-task probes while reading under dual-task conditions. The secondary task was to monitor the text for occurrences of the letter e. In Experiment 1, reading comprehension was assessed with a multiple-choice recognition test; in Experiment 2, subjects recalled the text. In both experiments, the secondary task replicated the well-known missing-letter effect in which detection of e’s was less effective for the word the. Letter detection was also more effective when subjects were on task, but this effect did not interact with the missing-letter effect. Comprehension was assessed in both the dual-task conditions and in a control single-task conditions. In the single-task conditions, both recognition (Experiment 1 and recall (Experiment 2 was better when subjects were on task, replicating previous research on mind wandering. Surprisingly, though, comprehension under dual-task conditions only showed an effect of being on task when measured with recall; there was no effect on recognition performance. Our interpretation of this pattern of results is that subjects generate their response to on-task probes on the basis of a retrospective assessment of the contents of working memory. Further, we argue that under dual-task conditions, the contents of working memory is not related to the reading processes required for accurate recognition performance. These conclusions have implications for models of text comprehension and for the interpretation of on-task probe responses.

  3. The search for the engram in eyeblink conditioning: A synopsis of past and present perspectives on the role of the cerebellum.

    Science.gov (United States)

    Foy, Michael R; Foy, Judith G

    2016-12-01

    One of the most prolific behavioral neuroscientists of his generation, Richard F. Thompson published more than 450 research articles during his almost 60-year career before his death in 2014. The breadth and reach of his scholarship has extended to a large multidisciplinary audience of scientists. The focal point of this article is arguably his most influential paper on cerebellar classical conditioning entitled "The Neurobiology of Learning and Memory" that appeared in Science in 1986 and has been cited 700 times since its publication. Here, a summary of the initial Thompson laboratory research leading up to an understanding of the cerebellum and its critical role in memory traces will be discussed, along with conclusions from the Science article pertinent to cerebellar classical conditioning. The summary will also discuss how the original 1986 article continues to stimulate and influence new research and provide further insights into the role of the cerebellum in the neurobiology of learning and memory function relevant to studies of mammalian classical conditioning. (PsycINFO Database Record

  4. OTVE turbopump condition monitoring, task E.5

    Science.gov (United States)

    Coleman, Paul T.; Collins, J. J.

    1989-01-01

    Recent work has been carried out on development of isotope wear analysis and optical and eddy current technologies to provide bearing wear measurements and real time monitoring of shaft speed, shaft axial displacement and shaft orbit of the Orbit Transfer Vehicle hydrostatic bearing tester. Results show shaft axial displacement can be optically measured (at the same time as shaft orbital motion and speed) to within 0.3 mils by two fiberoptic deflectometers. Evaluation of eddy current probes showed that, in addition to measuring shaft orbital motion, they can be used to measure shaft speed without having to machine grooves on the shaft surface as is the usual practice for turbomachinery. The interim results of this condition monitoring effort are presented.

  5. The Effect of Writing Task and Task Conditions on Colombian EFL Learners' Language Use

    Science.gov (United States)

    McDonough, Kim; Fuentes, César García

    2015-01-01

    This classroom study examines whether English L2 writers' language use differs depending on the writing task (operationalized as paragraph type), and task conditions (operationalized as individual or collaborative writing). The texts written by English L2 university students in Colombia (N = 26) in response to problem/solution and cause/effect…

  6. Eyeblink Synchrony in Multimodal Human-Android Interaction.

    Science.gov (United States)

    Tatsukawa, Kyohei; Nakano, Tamami; Ishiguro, Hiroshi; Yoshikawa, Yuichiro

    2016-12-23

    As the result of recent progress in technology of communication robot, robots are becoming an important social partner for humans. Behavioral synchrony is understood as an important factor in establishing good human-robot relationships. In this study, we hypothesized that biasing a human's attitude toward a robot changes the degree of synchrony between human and robot. We first examined whether eyeblinks were synchronized between a human and an android in face-to-face interaction and found that human listeners' eyeblinks were entrained to android speakers' eyeblinks. This eyeblink synchrony disappeared when the android speaker spoke while looking away from the human listeners but was enhanced when the human participants listened to the speaking android while touching the android's hand. These results suggest that eyeblink synchrony reflects a qualitative state in human-robot interactions.

  7. Modeling startle eyeblink electromyogram to assess fear learning.

    Science.gov (United States)

    Khemka, Saurabh; Tzovara, Athina; Gerster, Samuel; Quednow, Boris B; Bach, Dominik R

    2017-02-01

    Pavlovian fear conditioning is widely used as a laboratory model of associative learning in human and nonhuman species. In this model, an organism is trained to predict an aversive unconditioned stimulus from initially neutral events (conditioned stimuli, CS). In humans, fear memory is typically measured via conditioned autonomic responses or fear-potentiated startle. For the latter, various analysis approaches have been developed, but a systematic comparison of competing methodologies is lacking. Here, we investigate the suitability of a model-based approach to startle eyeblink analysis for assessment of fear memory, and compare this to extant analysis strategies. First, we build a psychophysiological model (PsPM) on a generic startle response. Then, we optimize and validate this PsPM on three independent fear-conditioning data sets. We demonstrate that our model can robustly distinguish aversive (CS+) from nonaversive stimuli (CS-, i.e., has high predictive validity). Importantly, our model-based approach captures fear-potentiated startle during fear retention as well as fear acquisition. Our results establish a PsPM-based approach to assessment of fear-potentiated startle, and qualify previous peak-scoring methods. Our proposed model represents a generic startle response and can potentially be used beyond fear conditioning, for example, to quantify affective startle modulation or prepulse inhibition of the acoustic startle response. © 2016 The Authors. Psychophysiology published by Wiley Periodicals, Inc. on behalf of Society for Psychophysiological Research.

  8. SOLUTION OF TASKS AS CONDITION OF FORMATION OF PROFESSIONAL THINKING

    Directory of Open Access Journals (Sweden)

    A. Kh. Kurashinova

    2016-01-01

    Full Text Available The modern labor market waits for the expert trained not only theoretically, but also practically, and it means that knowledge in the respective area is obviously not enough. Effectively to work in this or that field, at a stage of high school training future specialists need to impart skills of the practical solution of professional tasks and by that to develop interest in future profession. At the same time, despite a sufficient theoretical and experienced and experimental readiness of a problem of forming of professional thinking, there is a contradiction between requirements of society imposed to professional training and the actual level of practical cogitative readiness of the modern graduate than and relevance of this scientific article and its problem is determined. The work purpose – theoretically to prove a possibility of development of professional thinking at a stage of high school training through special didactic model and at the same time to draw attention to the problems of modern education connected with insufficient practical readiness of university graduates. Object of a research is professional training of future specialist in system of high school education. A subject – problem (training tasks based form of educational process organization in higher education institution as a condition of forming of professional thinking. The scientific article contains selective data of the conducted experienced pilot study of a problem. 

  9. Surface electromyography recording of spontaneous eyeblinks: applications in neuroprosthetics.

    Science.gov (United States)

    Frigerio, Alice; Brenna, Stefano; Cavallari, Paolo

    2013-02-01

    We are designing an implantable neuroprosthesis for the treatment of unilateral facial paralysis. The envisioned biomimetic device paces artificial blinks in the paretic eyelid when activity in the healthy orbicularis oculi (orbicularis) muscle is detected. The present article focuses on electromyography (EMG)-based eyeblink detection. A pilot clinical study was performed in healthy volunteers who were intended to represent individuals with facial paralysis. Spontaneous eyeblinks were detected by a surface EMG recording. Blink detection accuracy was tested at rest and during voluntary smiling and chewing. Fifteen participants were asked to wear surface recording electrodes on the left side of their face, detecting the orbicularis oculi, the masseter, and the zygomatic muscle EMG activity. Participants were asked to look ahead, voluntarily smile, and chew according to an experimental protocol. Custom software was designed with the purpose of selectively filtering the multichannel EMG recordings and triggering a digital output. The software filter allowed elimination of spurious artificial eyeblinks and thus increased the accuracy of the EMG recording apparatus for the spontaneous blinking. Orbicularis oculi EMG recording worked as a real-time eyeblink-detecting system. Moreover, the multichannel EMG recording coupled to a proper digital signal processing was very effective in specifically detecting the spontaneous blinking during other facial muscle activities. With regard to closed-loop biomimetic devices for the pacing of the eyeblink, the EMG signal represents a valid option for the recording side.

  10. Tourette Syndrome: Complementary Insights from Measures of Cognitive Control, Eyeblink Rate, and Pupil Diameter

    Science.gov (United States)

    Tharp, Jordan A.; Wendelken, Carter; Mathews, Carol A.; Marco, Elysa J.; Schreier, Herbert; Bunge, Silvia A.

    2015-01-01

    Some individuals with Tourette syndrome (TS) have severe motoric and vocal tics that interfere with all aspects of their lives, while others have mild tics that pose few problems. We hypothesize that observed tic severity reflects a combination of factors, including the degree to which dopaminergic (DA) and/or noradrenergic (NE) neurotransmitter systems have been affected by the disorder, and the degree to which the child can exert cognitive control to suppress unwanted tics. To explore these hypotheses, we collected behavioral and eyetracking data from 26 patients with TS and 26 controls between ages 7 and 14, both at rest and while they performed a test of cognitive control. To our knowledge, this is the first study to use eyetracking measures in patients with TS. We measured spontaneous eyeblink rate as well as pupil diameter, which have been linked, respectively, to DA and NE levels in the central nervous system. Here, we report a number of key findings that held when we restricted analyses to unmedicated patients. First, patients’ accuracy on our test of cognitive control accounted for fully 50% of the variance in parentally reported tic severity. Second, patients exhibited elevated spontaneous eyeblink rates compared to controls, both during task performance and at rest, consistent with heightened DA transmission. Third, although neither task-evoked pupil dilation nor resting pupil diameter differed between TS patients and controls, pupil diameter was positively related to parentally reported anxiety levels in patients, suggesting heightened NE transmission in patients with comorbid anxiety. Thus, with the behavioral and eyetracking data gathered from a single task, we can gather objective data that are related both to tic severity and anxiety levels in pediatric patients with TS, and that likely reflect patients’ underlying neurochemical disturbances. PMID:26175694

  11. Examining depletion theories under conditions of within-task transfer.

    Science.gov (United States)

    Brewer, Gene A; Lau, Kevin K H; Wingert, Kimberly M; Ball, B Hunter; Blais, Chris

    2017-07-01

    In everyday life, mental fatigue can be detrimental across many domains including driving, learning, and working. Given the importance of understanding and accounting for the deleterious effects of mental fatigue on behavior, a growing body of literature has studied the role of motivational and executive control processes in mental fatigue. In typical laboratory paradigms, participants complete a task that places demand on these self-control processes and are later given a subsequent task. Generally speaking, decrements to subsequent task performance are taken as evidence that the initial task created mental fatigue through the continued engagement of motivational and executive functions. Several models have been developed to account for negative transfer resulting from this "ego depletion." In the current study, we provide a brief literature review, specify current theoretical approaches to ego-depletion, and report an empirical test of current models of depletion. Across 4 experiments we found minimal evidence for executive control depletion along with strong evidence for motivation mediated ego depletion. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  12. Toward an understanding of the emotion-modulated startle eyeblink reflex: the case of anger.

    Science.gov (United States)

    Peterson, Carly K; Harmon-Jones, Eddie

    2012-11-01

    Three studies investigated the effect of angering pictures on the startle eyeblink response, based on anger's unique identity as an approach-oriented negative affect. In Study 1, eyeblinks to startling noise probes during angering and neutral pictures did not differ, despite angering pictures being rated higher on arousal and anger and more negative in valence. Study 2 replicated Study 1; also, dysphoric participants exhibited potentiated eyeblinks to probes during angering pictures much like those to probes during fear/disgust stimuli. A follow-up study revealed that dysphoric participants rated angering pictures higher in fear. Study 3 again found that eyeblinks to probes during angering and neutral pictures did not differ. Taken together, these results suggest that probes during angering stimuli elicit eyeblinks much like those during neutral stimuli, perhaps due to the competing influences of arousal, valence, and motivation on the startle eyeblink reflex.

  13. The significance of task significance: Job performance effects, relational mechanisms, and boundary conditions.

    Science.gov (United States)

    Grant, Adam M

    2008-01-01

    Does task significance increase job performance? Correlational designs and confounded manipulations have prevented researchers from assessing the causal impact of task significance on job performance. To address this gap, 3 field experiments examined the performance effects, relational mechanisms, and boundary conditions of task significance. In Experiment 1, fundraising callers who received a task significance intervention increased their levels of job performance relative to callers in 2 other conditions and to their own prior performance. In Experiment 2, task significance increased the job dedication and helping behavior of lifeguards, and these effects were mediated by increases in perceptions of social impact and social worth. In Experiment 3, conscientiousness and prosocial values moderated the effects of task significance on the performance of new fundraising callers. The results provide fresh insights into the effects, relational mechanisms, and boundary conditions of task significance, offering noteworthy implications for theory, research, and practice on job design, social information processing, and work motivation and performance.

  14. Force Based Skill Learning for Robot Tasks in Contact Conditions

    Institute of Scientific and Technical Information of China (English)

    王琴; 梅志千; 张广立; 杨汝清

    2004-01-01

    To acquire human operation skill based on force sense, element contact form (ECF) is proposed to describe contact condition firstly. The skill is modeled as a sequence of discrete ECFs. Since different ECF has different force distribution, a support vector machine classifier is built to identify the contact conditions according to the force signal. Finally, the robot can obtain the skill from the human demonstration.

  15. Effects of meditation practice on spontaneous eyeblink rate.

    Science.gov (United States)

    Kruis, Ayla; Slagter, Heleen A; Bachhuber, David R W; Davidson, Richard J; Lutz, Antoine

    2016-05-01

    A rapidly growing body of research suggests that meditation can change brain and cognitive functioning. Yet little is known about the neurochemical mechanisms underlying meditation-related changes in cognition. Here, we investigated the effects of meditation on spontaneous eyeblink rates (sEBR), a noninvasive peripheral correlate of striatal dopamine activity. Previous studies have shown a relationship between sEBR and cognitive functions such as mind wandering, cognitive flexibility, and attention-functions that are also affected by meditation. We therefore expected that long-term meditation practice would alter eyeblink activity. To test this, we recorded baseline sEBR and intereyeblink intervals (IEBI) in long-term meditators (LTM) and meditation-naive participants (MNP). We found that LTM not only blinked less frequently, but also showed a different eyeblink pattern than MNP. This pattern had good to high degree of consistency over three time points. Moreover, we examined the effects of an 8-week course of mindfulness-based stress reduction on sEBR and IEBI, compared to an active control group and a waitlist control group. No effect of short-term meditation practice was found. Finally, we investigated whether different types of meditation differentially alter eyeblink activity by measuring sEBR and IEBI after a full day of two kinds of meditation practices in the LTM. No effect of meditation type was found. Taken together, these findings may suggest either that individual difference in dopaminergic neurotransmission is a self-selection factor for meditation practice, or that long-term, but not short-term meditation practice induces stable changes in baseline striatal dopaminergic functioning.

  16. Peculiarities of latent inhibition formation in SHR rats in conditioned task of different complexity.

    Science.gov (United States)

    Kostyunina, N V; Loskutova, L V

    2012-05-01

    Inhibition of attention to irrelevant stimuli was studied in SHR rats using latent inhibition test. Latent inhibition was formed in two types of conditioned tasks with different levels of complexity and stress. Passive and active avoidance conditioning was preceded by preexposure to conditioned stimulus consisting of 20 and 100 non-reinforced presentations, respectively. Control Wistar rats demonstrated successful formation of latent inhibition in both tasks. SHR rats showed different degree of disruption of latent inhibition depending on the type of behavioral task. We assume that learning defect in these animals in respect to both novel and preexposed conditioned stimuli is associated with the lack of behavioral inhibition.

  17. The Effects of Context Changes on the Reinstatement of Extinguished Conditioned Behavior in a Conditioned Suppression Task with Humans

    Science.gov (United States)

    Neumann, David L.

    2008-01-01

    Reinstatement refers to the return of previously extinguished conditioned responses to test trials of a conditional stimulus (CS) when presentations of the unconditional stimulus (US) alone are given following extinction. Four experiments were conducted to determine whether reinstatement could be found in a conditioned suppression task with humans…

  18. Sensory prediction or motor control? Application of marr-albus type models of cerebellar function to classical conditioning.

    Science.gov (United States)

    Lepora, Nathan F; Porrill, John; Yeo, Christopher H; Dean, Paul

    2010-01-01

    Marr-Albus adaptive filter models of the cerebellum have been applied successfully to a range of sensory and motor control problems. Here we analyze their properties when applied to classical conditioning of the nictitating membrane response in rabbits. We consider a system-level model of eyeblink conditioning based on the anatomy of the eyeblink circuitry, comprising an adaptive filter model of the cerebellum, a comparator model of the inferior olive and a linear dynamic model of the nictitating membrane plant. To our knowledge, this is the first model that explicitly includes all these principal components, in particular the motor plant that is vital for shaping and timing the behavioral response. Model assumptions and parameters were systematically investigated to disambiguate basic computational capacities of the model from features requiring tuning of properties and parameter values. Without such tuning, the model robustly reproduced a range of behaviors related to sensory prediction, by displaying appropriate trial-level associative learning effects for both single and multiple stimuli, including blocking and conditioned inhibition. In contrast, successful reproduction of the real-time motor behavior depended on appropriate specification of the plant, cerebellum and comparator models. Although some of these properties appear consistent with the system biology, fundamental questions remain about how the biological parameters are chosen if the cerebellar microcircuit applies a common computation to many distinct behavioral tasks. It is possible that the response profiles in classical conditioning of the eyeblink depend upon operant contingencies that have previously prevailed, for example in naturally occurring avoidance movements.

  19. Comparison of eyeblink monitoring and EEG signal analysis for mental fatigue assessment

    Science.gov (United States)

    Królak, Aleksandra; Strumiłło, Paweł

    2008-01-01

    Mental fatigue in humans is a major cause of accidents in occupations requiring constant attention. The most promising indicators of fatigue are eyeblink dynamics and electroencephalography. This paper presents the results of a study aimed at establishing the dependence between eyeblink dynamics and EEG signal changes during transition to mental fatigue.

  20. Boundary Conditions for a New Type of Design Task

    DEFF Research Database (Denmark)

    McAloone, Tim C.

    2011-01-01

    object and research paradigm, studying service‐oriented approaches to product development and seeking to understand how to spell the systematic development of these so-called Product/Service‐Systems (PSS). When considering the shift towards PSS in the domain of engineering, it is in......-teresting to understand the shifting focus and identification of boundary conditions that manufacturing organisations must undergo, in order to develop just as systematic an approach to the service-related aspects of their business development, as they have in place for their product development. This chapter......Manufacturing companies have traditionally focused their efforts on developing and producing physical products for the market. Currently, however, many companies are rethinking their business strategies, from selling products to providing services. In place of the product alone, the activity...

  1. The Operator's Diagnosis Task under Abnormal Operating Conditions in Industrial Process Plant

    DEFF Research Database (Denmark)

    Goodstein, L.P.; Pedersen, O.M.; Rasmussen, Jens

    1974-01-01

    Analysis of serious accidents in connection with the operation of technical installations demonstrate that the diagnosis task which confronts personnel under non-normal plant conditions is a critical one. This report presents a preliminary outline of characteristic traits connected with the task...

  2. Relationships of physical job tasks and living conditions with occupational injuries in coal miners

    Energy Technology Data Exchange (ETDEWEB)

    Ashis Bhattacherjee; Jean-Pierre Bertrand; Jean-Pierre Meyer (and others) [Indian Institute of Technology (India). Department of Mining Engineering

    2007-04-15

    This study assessed the relationships of job tasks and living conditions with occupational injuries among coal miners. The sample included randomly selected 516 underground workers. They completed a standardized self-administred questionnaire. The data were analyzed via logistic regression method. The rate of injuries in the past two years was 29.8%. The job tasks with significant crude relative risks were: power hammer, vibrating hand tools, pneumatic tools, bent trunk, awkward work posture, heat, standing about and walking, job tasks for trunk and upper/lower limbs, pain caused by work, and muscular tiredness. Logistic model shows a strong relationship between the number of job tasks (JT) and injuries and significant ORs=1.71 for face work, not-good-health-status, and psychotropic drug use. Musculoskeletal disorders and certain personality traits were also significant in univariate analysis. Therefore job tasks and living conditions strongly increase the injuries, and occupational physicians could help workers to find remedial measures.

  3. Sex differences in learning processes of classical and operant conditioning.

    Science.gov (United States)

    Dalla, Christina; Shors, Tracey J

    2009-05-25

    Males and females learn and remember differently at different times in their lives. These differences occur in most species, from invertebrates to humans. We review here sex differences as they occur in laboratory rodent species. We focus on classical and operant conditioning paradigms, including classical eyeblink conditioning, fear-conditioning, active avoidance and conditioned taste aversion. Sex differences have been reported during acquisition, retention and extinction in most of these paradigms. In general, females perform better than males in the classical eyeblink conditioning, in fear-potentiated startle and in most operant conditioning tasks, such as the active avoidance test. However, in the classical fear-conditioning paradigm, in certain lever-pressing paradigms and in the conditioned taste aversion, males outperform females or are more resistant to extinction. Most sex differences in conditioning are dependent on organizational effects of gonadal hormones during early development of the brain, in addition to modulation by activational effects during puberty and adulthood. Critically, sex differences in performance account for some of the reported effects on learning and these are discussed throughout the review. Because so many mental disorders are more prevalent in one sex than the other, it is important to consider sex differences in learning when applying animal models of learning for these disorders. Finally, we discuss how sex differences in learning continue to alter the brain throughout the lifespan. Thus, sex differences in learning are not only mediated by sex differences in the brain, but also contribute to them.

  4. Performance in eyeblink conditioning is age and sex dependent

    NARCIS (Netherlands)

    Löwgren, Karolina; Bååth, Rasmus; Rasmussen, Anders; Boele, Henk-Jan; Koekkoek, Sebastiaan K E; De Zeeuw, Chris I; Hesslow, Germund

    2017-01-01

    A growing body of evidence suggests that the cerebellum is involved in both cognition and language. Abnormal cerebellar development may contribute to neurodevelopmental disorders such as attention deficit hyperactivity disorder (ADHD), autism, fetal alcohol syndrome, dyslexia, and specific language

  5. Interaction of Reinforcement Conditions and Developmental Level in a Two-Choice Discrimination Task with Children

    Science.gov (United States)

    Tindall, Robert C.; Ratliff, Richard G.

    1974-01-01

    Reports a study of 540 first-, fourth-, and eighth-grade students who participated in a discrimination task under three reinforcement conditions: reward, punishment and a combination of both. Results indicate the superiority of learning under punishment conditions. Interactions involving the sex of subject and experimenter are also discussed.…

  6. Task-related functional connectivity in autism spectrum conditions: an EEG study using wavelet transform coherence

    Directory of Open Access Journals (Sweden)

    Catarino Ana

    2013-01-01

    Full Text Available Abstract Background Autism Spectrum Conditions (ASC are a set of pervasive neurodevelopmental conditions characterized by a wide range of lifelong signs and symptoms. Recent explanatory models of autism propose abnormal neural connectivity and are supported by studies showing decreased interhemispheric coherence in individuals with ASC. The first aim of this study was to test the hypothesis of reduced interhemispheric coherence in ASC, and secondly to investigate specific effects of task performance on interhemispheric coherence in ASC. Methods We analyzed electroencephalography (EEG data from 15 participants with ASC and 15 typical controls, using Wavelet Transform Coherence (WTC to calculate interhemispheric coherence during face and chair matching tasks, for EEG frequencies from 5 to 40 Hz and during the first 400 ms post-stimulus onset. Results Results demonstrate a reduction of interhemispheric coherence in the ASC group, relative to the control group, in both tasks and for all electrode pairs studied. For both tasks, group differences were generally observed after around 150 ms and at frequencies lower than 13 Hz. Regarding within-group task comparisons, while the control group presented differences in interhemispheric coherence between faces and chairs tasks at various electrode pairs (FT7-FT8, TP7-TP8, P7-P8, such differences were only seen for one electrode pair in the ASC group (T7-T8. No significant differences in EEG power spectra were observed between groups. Conclusions Interhemispheric coherence is reduced in people with ASC, in a time and frequency specific manner, during visual perception and categorization of both social and inanimate stimuli and this reduction in coherence is widely dispersed across the brain. Results of within-group task comparisons may reflect an impairment in task differentiation in people with ASC relative to typically developing individuals. Overall, the results of this research support the value of WTC

  7. Healthy older adults balance pattern under dual task conditions: exploring the strategy and trend

    Directory of Open Access Journals (Sweden)

    Bahareh Zeynalzadeh Ghoochani

    2016-10-01

    Full Text Available Background: In line with health promotion plans, early intervention and fall prevention in geriatric population, it is important to study healthy individuals balance mechanisms. The aim of this research was to investigate the effect of adding and removing visual input and dual task on elderly balance. Methods: Twenty healthy elderly recruited from four different senior citizen health club centers and from the University of Social Welfare and Rehabilitation Sciences (USWR participated in this analytic cross-sectional study. At USWR’s Motor Control Laboratory, the participants’ postural sway were assessed using force plate in 4 distinct double leg standing conditions with and without presence of visual input and Stroop dual task. Postural and Stroop variables were compared. Results: Findings indicated that when the elderly encountered with either dual task or absence of visual input, they can still manage the situation in a way that changes in sway parameter would not become significant. But, when these two conditions occurred simultaneously, the participant’s balance strategy fluctuated. Therefore, the mean velocity showed a significant difference between the "single quiet standing" condition and the condition of standing with eyes closed while the participants were answering Stroop dual task (Mean difference = -0.007, 95% CI = -0.012, -0.002. Conclusion: It appears that velocity parameter is sensitive to small changes, so it is recommended that researchers include this parameter in their future analyses. Balance in elderly can be manipulated by dual task and visual input deprivation.

  8. Healthy older adults balance pattern under dual task conditions: exploring the strategy and trend

    Science.gov (United States)

    Zeynalzadeh Ghoochani, Bahareh; Hosseini, Seyed Ali; Talebian, Saeed; Biglarian, Akbar; Zeinalzadeh, Afsaneh; Nazary-Moghadam, Salman; Derakhshanrad, Seyed Alireza

    2016-01-01

    Background: In line with health promotion plans, early intervention and fall prevention in geriatric population, it is important to study healthy individuals balance mechanisms. The aim of this research was to investigate the effect of adding and removing visual input and dual task on elderly balance. Methods: Twenty healthy elderly recruited from four different senior citizen health club centers and from the University of Social Welfare and Rehabilitation Sciences (USWR) participated in this analytic cross-sectional study. At USWR’s Motor Control Laboratory, the participants’ postural sway were assessed using force plate in 4 distinct double leg standing conditions with and without presence of visual input and Stroop dual task. Postural and Stroop variables were compared. Results: Findings indicated that when the elderly encountered with either dual task or absence of visual input, they can still manage the situation in a way that changes in sway parameter would not become significant. But, when these two conditions occurred simultaneously, the participant’s balance strategy fluctuated. Therefore, the mean velocity showed a significant difference between the “single quiet standing” condition and the condition of standing with eyes closed while the participants were answering Stroop dual task (Mean difference = -0.007, 95% CI = -0.012, -0.002). Conclusion: It appears that velocity parameter is sensitive to small changes, so it is recommended that researchers include this parameter in their future analyses. Balance in elderly can be manipulated by dual task and visual input deprivation.

  9. Spatial representations in dorsal hippocampal neurons during a tactile-visual conditional discrimination task.

    Science.gov (United States)

    Griffin, Amy L; Owens, Cullen B; Peters, Gregory J; Adelman, Peter C; Cline, Kathryn M

    2012-02-01

    Trajectory-dependent coding in dorsal CA1 of hippocampus has been evident in various spatial memory tasks aiming to model episodic memory. Hippocampal neurons are considered to be trajectory-dependent if the neuron has a place field located on an overlapping segment of two trajectories and exhibits a reliable difference in firing rate between the two trajectories. It is unclear whether trajectory-dependent coding in hippocampus is a mechanism used by the rat to solve spatial memory tasks. A first step in answering this question is to compare results between studies using tasks that require spatial working memory and those that do not. We recorded single units from dorsal CA1 of hippocampus during performance of a discrete-trial, tactile-visual conditional discrimination (CD) task in a T-maze. In this task, removable floor inserts that differ in texture and appearance cue the rat to visit either the left or right goal arm to receive a food reward. Our goal was to assess whether trajectory coding would be evident in the CD task. Our results show that trajectory coding was rare in the CD task, with only 12 of 71 cells with place fields on the maze stem showing a significant firing rate difference between left and right trials. For comparison, we recorded from dorsal CA1 during the acquisition and performance of a continuous spatial alternation task identical to that used in previous studies and found a proportion of trajectory coding neurons similar to what has been previously reported. Our data suggest that trajectory coding is not a universal mechanism used by the hippocampus to disambiguate similar trajectories, and instead may be more likely to appear in tasks that require the animal to retrieve information about a past trajectory, particularly in tasks that are continuous rather than discrete in nature.

  10. Condition Monitoring of Cables Task 3 Report: Condition Monitoring Techniques for Electric Cables

    Energy Technology Data Exchange (ETDEWEB)

    Villaran, M.; Lofaro, R.; na

    2009-11-30

    For more than 20 years the NRC has sponsored research studying electric cable aging degradation, condition monitoring, and environmental qualification testing practices for electric cables used in nuclear power plants. This report summarizes several of the most effective and commonly used condition monitoring techniques available to detect damage and measure the extent of degradation in electric cable insulation. The technical basis for each technique is summarized, along with its application, trendability of test data, ease of performing the technique, advantages and limitations, and the usefulness of the test results to characterize and assess the condition of electric cables.

  11. The effect of task complexity and task conditions on foreign language development and performance: three empirical studies

    OpenAIRE

    Sercu, L.; Wachter, L; Peters, E.; Kuiken, F.; Vedder, I.

    2006-01-01

    It has been argued that tasks constitute a valid alternative unit to sequence the language learning process, as opposed to linguistically defined syllabuses. Implementing this claim presupposes that it is possible to access the cognitive and linguistic demands of tasks, so that they can be sequenced in such a way that they optimally support and promote the L2 learning process. Knowing what demands a task will make opens up the possibility of using task design to manipulate the learner's atten...

  12. Formative Research on the Simplifying Conditions Method (SCM) for Task Analysis and Sequencing.

    Science.gov (United States)

    Kim, YoungHwan; Reigluth, Charles M.

    The Simplifying Conditions Method (SCM) is a set of guidelines for task analysis and sequencing of instructional content under the Elaboration Theory (ET). This article introduces the fundamentals of SCM and presents the findings from a formative research study on SCM. It was conducted in two distinct phases: design and instruction. In the first…

  13. Sonification of in-vehicle interface reduces gaze movements under dual-task condition.

    Science.gov (United States)

    Tardieu, Julien; Misdariis, Nicolas; Langlois, Sabine; Gaillard, Pascal; Lemercier, Céline

    2015-09-01

    In-car infotainment systems (ICIS) often degrade driving performances since they divert the driver's gaze from the driving scene. Sonification of hierarchical menus (such as those found in most ICIS) is examined in this paper as one possible solution to reduce gaze movements towards the visual display. In a dual-task experiment in the laboratory, 46 participants were requested to prioritize a primary task (a continuous target detection task) and to simultaneously navigate in a realistic mock-up of an ICIS, either sonified or not. Results indicated that sonification significantly increased the time spent looking at the primary task, and significantly decreased the number and the duration of gaze saccades towards the ICIS. In other words, the sonified ICIS could be used nearly exclusively by ear. On the other hand, the reaction times in the primary task were increased in both silent and sonified conditions. This study suggests that sonification of secondary tasks while driving could improve the driver's visual attention of the driving scene.

  14. Task-specific enhancement of hippocampus-dependent learning in mice deficient in monoacylglycerol lipase, the major hydrolyzing enzyme of the endocannabinoid 2-arachidonoylglycerol

    Directory of Open Access Journals (Sweden)

    Yasushi eKishimoto

    2015-06-01

    Full Text Available Growing evidence indicates that the endocannabinoid system is important for the acquisition and/or extinction of learning and memory. However, it is unclear which endocannabinoid(s play(s a crucial role in these cognitive functions, especially memory extinction. To elucidate the physiological role of 2-arachidonoylglycerol (2-AG, a major endocannabinoid, in behavioral and cognitive functions, we conducted a comprehensive behavioral test battery in knockout (KO mice deficient in monoacylglycerol lipase (MGL, the major hydrolyzing enzyme of 2-AG. We found age-dependent increases in spontaneous physical activity in MGL KO mice. Next, we tested the MGL KO mice using 5 hippocampus-dependent learning paradigms (i.e., Morris water maze [MWM], contextual fear conditioning, novel object recognition test, trace eyeblink conditioning, and water-finding test. In the MWM, MGL KO mice showed normal acquisition of reference memory, but exhibited significantly faster extinction of the learned behavior. Moreover, they showed faster memory acquisition on the reversal-learning task of the MWM. In contrast, in the contextual fear conditioning, MGL KO mice tended to show slower memory extinction. In the novel object recognition and water-finding tests, MGL KO mice exhibited enhanced memory acquisition. Trace eyeblink conditioning was not altered in MGL KO mice throughout the acquisition and extinction phases. These results indicate that 2-AG signaling is important for hippocampus-dependent learning and memory, but its contribution is highly task-dependent.

  15. The Effects of Varied Extinction Conditions Following Acquisition on a 100 Per Cent Rewarded Task in Alcoholics and Nonalcoholics.

    Science.gov (United States)

    Okultich, Peter V.; Marlatt, G. Alan

    The purpose of this study was two-fold: (1) to determine whether alcoholics will show greater persistance in responding under punishment in a simple operant task as compared to nonalcoholics; and (2) with this task, under what conditions alcoholics will suppress their responses to the same extent as nonalcoholics. In the task, all subjects during…

  16. The effect of task complexity and task conditions on foreign language development and performance: three empirical studies

    NARCIS (Netherlands)

    Sercu, L.; de Wachter, L.; Peters, E.; Kuiken, F.; Vedder, I.

    2006-01-01

    It has been argued that tasks constitute a valid alternative unit to sequence the language learning process, as opposed to linguistically defined syllabuses. Implementing this claim presupposes that it is possible to access the cognitive and linguistic demands of tasks, so that they can be sequenced

  17. Disruption of latent inhibition by interpolation of task-irrelevant stimulation between preexposure and conditioning.

    Science.gov (United States)

    Escobar, Martha; Arcediano, Francisco; Miller, Ralph R

    2005-08-01

    Latent inhibition refers to attenuated responding to a conditioned stimulus (CS) that was repeatedly presented without reinforcement prior to the CS-unconditioned stimulus (US) pairings. Using water-deprived rats as subjects, we observed that interpolating task-irrelevant stimulation between the preexposure and conditioning phases of a latent inhibition procedure attenuated latent inhibition (Experiments 1A, 1B, and 2). Apparently, interpolated stimulation segments the preexposure and conditioning treatments into two separate experiences, much in the same way that a change of context would. Consistent with this view, the interpolated stimulation did not disrupt latent inhibition if it was also presented during both preexposure and conditioning (Experiment 3). We view these results as analogous to those of Escobar, Arcediano, and Miller (2003), who suggested that the difficulty in observing latent inhibition in human adults is related to the segmentation between preexposure and conditioning caused by the usual interpolation of instructions in preparations with humans.

  18. Role of human premotor dorsal region in learning a conditional visuomotor task.

    Science.gov (United States)

    Parikh, Pranav J; Santello, Marco

    2017-01-01

    Conditional learning is an important component of our everyday activities (e.g., handling a phone or sorting work files) and requires identification of the arbitrary stimulus, accurate selection of the motor response, monitoring of the response, and storing in memory of the stimulus-response association for future recall. Learning this type of conditional visuomotor task appears to engage the premotor dorsal region (PMd). However, the extent to which PMd might be involved in specific or all processes of conditional learning is not well understood. Using transcranial magnetic stimulation (TMS), we demonstrate the role of human PMd in specific stages of learning of a novel conditional visuomotor task that required subjects to identify object center of mass using a color cue and to apply appropriate torque on the object at lift onset to minimize tilt. TMS over PMd, but not vertex, increased error in torque exerted on the object during the learning trials. Analyses of digit position and forces further revealed that the slowing in conditional visuomotor learning resulted from impaired monitoring of the object orientation during lift, rather than stimulus identification, thus compromising the ability to accurately reduce performance error across trials. Importantly, TMS over PMd did not alter production of torque based on the recall of learned color-torque associations. We conclude that the role of PMd for conditional learning is highly sensitive to the stage of learning visuomotor associations.

  19. Modulation of anticipatory postural activity for multiple conditions of a whole-body pointing task.

    Science.gov (United States)

    Tolambiya, A; Chiovetto, E; Pozzo, T; Thomas, E

    2012-05-17

    This is a study on associated postural activities during the anticipatory segments of a multijoint movement. Several previous studies have shown that they are task dependant. The previous studies, however, have mostly been limited in demonstrating the presence of modulation for one task condition, that is, one aspect such as the distance of the target or the direction of reaching. Real-life activities like whole-body pointing, however, can vary in several ways. How specific is the adaptation of the postural activities for the diverse possibilities of a whole-body pointing task? We used a classification paradigm to answer this question. We examined the anticipatory postural electromyograms for four different types of whole-body pointing tasks. The presence of task-dependent modulations in these signals was probed by performing four-way classification tests using a support vector machine (SVM). The SVM was able to achieve significantly higher than chance performance in correctly predicting the movements at hand (Chance performance 25%). Using only anticipatory postural muscle activity, the correct movement at hand was predicted with a mean rate of 62%. Because this is 37% above chance performance, it suggests the presence of postural modulation for diverse conditions. The anticipatory activities consisted of both activations and deactivations. Movement prediction with the use of the activating muscles was significantly better than that obtained with the deactivating muscles. This suggests that more specific modulations for the movement at hand take place through activation, whereas the deactivation is more general. The study introduces a new method for investigating adaptations in motor control. It also sheds new light on the quantity and quality of information available in the feedforward segments of a voluntary multijoint motor activity.

  20. The effect of emotion on interpretation and logic in a conditional reasoning task.

    Science.gov (United States)

    Blanchette, Isabelle

    2006-07-01

    The effect of emotional content on logical reasoning is explored in three experiments. Theparticipants completed a conditional reasoning task (If p, then q) with emotional and neutral contents. In Experiment 1, existing emotional and neutral words were used. The emotional value of initially neutral words was experimentally manipulated in Experiments 1B and 2, using classical conditioning. In all experiments, participants were less likely to provide normatively correct answers when reasoning about emotional stimuli, compared with neutral stimuli. This was true for both negative (Experiments 1B and 2) and positive contents (Experiment 2). The participants' interpretations of the conditional statements were also measured (perceived sufficiency, necessity, causality, and plausibility). The results showed the expected relationship between interpretation and reasoning. However, emotion did not affect interpretation. Emotional and neutral conditional statements were interpreted similarly. The results are discussed in light of current models of emotion and reasoning.

  1. Startle eye-blink modulation by facial self-resemblance and current mood.

    Science.gov (United States)

    Finke, Johannes B; Larra, Mauro F; Schilling, Thomas M; Lass-Hennemann, Johanna; Blumenthal, Terry D; Schächinger, Hartmut

    2015-06-01

    Although salient stimuli are known to modulate startle eye-blink responses, and one's own face is considered of particular salience, effects of facial self-resemblance on startle responsiveness have not been systematically investigated. For the present study, pictures from the FACES database (rated as neutral) were digitally morphed to resemble the participants' (N=37) faces to varying degrees (25-50-75%). Perceptually matched geometrical shapes served as a control condition. At SOAs of either 300ms or 3000ms after picture onset, startle responses were elicited by white noise (50ms, 105dB), and recorded at the orbicularis oculi via EMG. Prior to the experiment, self-reported mood was assessed by means of the PANAS. Relative to non-face stimuli, the presentation of faces reduced startle magnitude at short, but not long, lead intervals. Furthermore, for probes presented at a SOA of 300ms, a linear decrease in startle magnitude with higher levels of self-resemblance was observed, presumably reflecting higher salience of the self-face. The startle modulating effect of self-resembling faces during longer lead intervals was moderated by the participants' current mood: negative affect predicted stronger patterns of attenuation, which might be interpreted as an increase in self-focus resulting from more negative mood.

  2. The effect of focused communication tasks on instructed acquisition of English past counterfactual conditionals

    Directory of Open Access Journals (Sweden)

    Anna Broszkiewicz

    2011-10-01

    Full Text Available One important controversy connected with the effectiveness of grammar teaching seems to have been resolved as there is ample empirical evidence testifying to the positive effect of form-focused instruction on second language acquisition (Nassaji & Fotos, 2004; Norris & Ortega, 2000; Spada, 1997, 2010. Nevertheless, there are still a number of problems open to debate and awaiting concrete solutions, such as how to establish connections between form and meaning and find the best way to teach grammar for implicit knowledge, which, in the opinion of most SLA researchers (Ellis, 2006a, p. 95 and according to numerous theoretical positions, is a key driver of linguistic competence. One of the options available to language educators is to employ focused communication tasks, which “are designed to elicit production of a specific target feature in the context of performing a communicative task” (Ellis, 2001, p. 21. The aim of the study reported in this article was to explore the effect of focused communication tasks on the instructed acquisition of English past counterfactual conditionals when compared with contextualized practice activities. The results of two types of intervention were measured employing a number of data collection instruments with a view to tapping both the explicit and implicit knowledge of the participants of the study. Both types of instructional treatment were equally effective in helping learners develop the explicit knowledge of past unreal conditionals, but when it comes to the implicit knowledge of the aforementioned structure, the group instructed by means of focused communication tasks outperformed the other experimental group and the control group, as evidenced by the results obtained from the individually elicited imitation test and the focused communication task performed in pairs.

  3. Task-specific focal dystonia - Genetics Home Reference [Genetics Home Reference (Conditions)

    Lifescience Database Archive (English)

    Full Text Available of particular tasks, such as writing, playing a musical instrument, or participating in a sport. Dystonias ...that occur while playing a musical instrument. This condition can affect amateur or professional musicians, ...and the location of the dystonia depends on the instrument. Some musicians (such as piano, guitar, and violi...ly painless, although they can cause anxiety when they interfere with musical performance and other activiti...opulation. Musician's dystonia that is severe enough to impact performance occurs in about 1 percent of music

  4. Quality of standing balance in community-dwelling elderly: Age-related differences in single and dual task conditions.

    Science.gov (United States)

    Coelho, Tiago; Fernandes, Ângela; Santos, Rubim; Paúl, Constança; Fernandes, Lia

    2016-01-01

    To examine the relationship between age and quality of standing balance in single and dual task conditions. A cross-sectional study was conducted using a sample of 243 community-dwellers aged ≥65 years. Quality of standing balance was assessed by measuring the center of pressure (COP) sway with a pressure platform. Measurements were performed under single task (orthostatic position) and dual task (orthostatic position while performing a verbal fluency task) conditions. The mean age of the participants was 79.1(±7.3)years and 76.1% were women. Older age was associated with an increased COP sway, mainly in the medial/lateral (ML) direction. Most COP sway parameters were higher under dual task conditions than under single task. After controlling for the effect of the number of words enunciated in dual task conditions, only the differences in COP sway parameters in the ML direction remained significant. There was no significant interaction between age group (65-79; ≥80 years) and condition, which indicates that differences in COP sway caused by performing a secondary task were similar for younger and for older participants. Age did not seem to influence significantly the decline in the quality of standing balance triggered by performing a concurrent cognitive task. However, older age was consistently associated with poorer standing balance, both in single and in dual task conditions. Therefore, performing a secondary task may lead older individuals to reach their postural stability limits and, consequently, to fall. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  5. Multiple memory systems, development and conditioning.

    Science.gov (United States)

    Stanton, M E

    2000-06-01

    A century of behavioral and neurobiological research suggests that Pavlovian conditioning involves three component memory systems: sensorimotor, affective and cognitive. In classical eyeblink conditioning, there is evidence that these three memory systems involve, respectively, the cerebellum, amygdala and hippocampus. This article reviews developmental research on eyeblink conditioning in rodents that is beginning to characterize ontogenetic dissociations and interactions among these memory systems. This research shows that the functional development of the affective system (conditioned fear response) precedes that of the sensorimotor system (conditioned eyeblink reflex). Modulation of these two systems by cognitive processes also seems to emerge at different points in ontogeny. Implications for cognitive development and research on multiple memory systems are discussed.

  6. Sensory prediction or motor control? Application of Marr-Albus type models of cerebellar function to classical conditioning

    Directory of Open Access Journals (Sweden)

    Nathan F Lepora

    2010-10-01

    Full Text Available Marr-Albus adaptive filter models of the cerebellum have been applied successfully to a range of sensory and motor control problems. Here we analyze their properties when applied to classical conditioning of the nictitating membrane response in rabbits. We consider a system-level model of eyeblink conditioning based on the anatomy of the eyeblink circuitry, comprising an adaptive filter model of the cerebellum, a comparator model of the inferior olive and a linear dynamic model of the nictitating membrane plant. To our knowledge, this is the first model that explicitly includes all these principal components, in particular the motor plant that is vital for shaping and timing the behavioral response. Model assumptions and parameters were systematically investigated to disambiguate basic computational capacities of the model from features requiring tuning of properties and parameter values. Without such tuning, the model robustly reproduced a range of behaviors related to sensory prediction, by displaying appropriate trial-level associative learning effects for both single and multiple stimuli, including blocking and conditioned inhibition. In contrast, successful reproduction of the real-time motor behavior depended on appropriate specification of the plant, cerebellum and comparator models. Although some of these properties appear consistent with the system biology, fundamental questions remain about how the biological parameters are chosen if the cerebellar microcircuit applies a common computation to many distinct behavioral tasks. It is possible that the response profiles in classical conditioning of the eyeblink depend upon operant contingencies that have previously prevailed, for example in naturally occurring avoidance movements.

  7. Differential gene expression in the rat hippocampus during learning of an operant conditioning task.

    Science.gov (United States)

    Rapanelli, M; Frick, L R; Zanutto, B S

    2009-11-10

    Changes in transcription levels of brain-derived neurotrophic factor (BDNF), cyclic adenosine monophosphate (cAMP) response element binding (CREB), Synapsin I, Ca(2+)/calmodulin-dependent protein kinase II (CamKII), activity-regulated cytoskeleton-associated protein (Arc), c-jun and c-fos have been associated to several learning paradigms in different brain areas. In this study, we measured mRNA expression in the hippocampus by real time (RT)-PCR mRNA levels of BDNF, CREB, Synapsin I, CamKII, Arc, c-jun and c-fos, during learning and operant conditioning task. Experimental groups were as follows: control (C, the animals never left the bioterium), when the animals reached 50-65% of the expected response (Incompletely Trained, IT), when animals reached 100% of the expected response with a latency time lower than 5 s (Trained, Tr), Box Control of Incompletely Trained (BCIT), animals spent the same time as the IT in the operant conditioning box and Box Control of Trained (BCTr) animals spent the same time as the Tr in the operant conditioning box. All rats were killed at the same time by cervical dislocation 15 min after training and hippocampi were removed and processed. We found increments of mRNA levels of most genes (BDNF, CREB, Synapsin I, Arc, c-jun and c-fos) in IT and Tr groups compared to their box controls, but increments in Tr were smaller compared with IT. These results describe a differential gene expression in the rat hippocampus when the animals are learning and when animals have already learned. Taking together the results presented herein with the known functions of these genes, we propose a link between changes in gene expression in the hippocampus and different degrees of cellular activation and plasticity during learning of an operant conditioning task.

  8. Effect of exercise on dual-task and balance on elderly in multiple disease conditions.

    Science.gov (United States)

    Zanotto, Tobia; Bergamin, Marco; Roman, Fausto; Sieverdes, John C; Gobbo, Stefano; Zaccaria, Marco; Ermolao, Andrea

    2014-01-01

    Investigations on how exercise and physical activity affect dual-task (DT) performance in the elderly are growing rapidly due to the fact that DT activities are commonplace with activities of daily living. Preliminary evidence has shown the benefit in exercise on DT balance, though it is unclear to what extent the effect exercise has on DT performance in elderly subjects with disease conditions, including subjects with a high risk of falls. Hence, the objective of this study was to critically review the existing evidence of a potential relationship between exercise and improvement of static and dynamic balance during DT conditions as well as secondary outcomes in elderly subjects with different disease conditions. A systematic search using online databases was performed to source documents. Inclusion criteria sourced articles classified as randomized controlled trials (RCT), controlled trials (CT) and uncontrolled trials (UT). Moreover, the studies had to administrate an exercise or physical activity protocol in the intervention. Seventeen studies met the eligibility criteria and were comprised of 12 RCTs, 3 CTs, and 2 UTs. Overall, 13 studies supported exercise being effective to improve parameters of static and dynamic balance during single or DT conditions. Despite the heterogeneity of pathologic conditions, exercise showed similar benefits to improve function in two main areas: neurological conditions and frailty conditions. The lack of a common method to assess DT performance limited the ability to compare different interventions directly. Future research is warranted to study the optimal dose and exercise modalities to best reduce the risk of falls in the elderly with multiple disease conditions.

  9. IEA SHC Task 38 'Solar air-conditioning and refrigeration'. Danish participation 2007-2010. Appendix; IEA SHC Task 38 'Solar air-conditioning and refrigeration'. Dansk deltagelse 2007-2010. Bilag

    Energy Technology Data Exchange (ETDEWEB)

    Ellehauge, K. (Ellehauge og Kildemoes, Aarhus (Denmark)); Muenster, E. (PlanEnergi, Skoerping (Denmark)); Reinholdt, L. (Teknologisk Institut, Aarhus (Denmark)); Munds, S. (AC-Sun Aps, Horsens (Denmark))

    2011-03-15

    IEA SHC Task 38 'Solar Air-Conditioning and Refrigeration' ran from October 2006 to December 2010. Denmark was represented in the task from January 2007 to December 2010. The aim of the task was to encourage use of solar powered refrigeration and air conditioning systems in particular at residential, commercial and industrial sectors. Furthermore, the aim was to contribute to new research and development activities on new systems and concepts. The appendix contains the publications prepared by the Danish project group.(LN)

  10. A BOLD signature of eyeblinks in the visual cortex.

    Science.gov (United States)

    Hupé, Jean-Michel; Bordier, Cécile; Dojat, Michel

    2012-05-15

    We are usually unaware of the brief but large illumination changes caused by blinks, presumably because of blink suppression mechanisms. In fMRI however, increase of the BOLD signal was reported in the visual cortex, e.g. during blocks of voluntary blinks (Bristow, Frith and Rees, 2005) or after spontaneous blinks recorded during the prolonged fixation of a static stimulus (Tse, Baumgartner and Greenlee, 2010). We tested whether such activation, possibly related to illumination changes, was also present during standard fMRI retinotopic and visual experiments and was large enough to contaminate the BOLD signal we are interested in. We monitored in a 3T scanner the eyeblinks of 14 subjects who observed three different types of visual stimuli, including periodic rotating wedges and contracting/expanding rings, event-related Mondrians and graphemes, while fixating. We performed event-related analyses on the set of detected spontaneous blinks. We observed large and widespread BOLD responses related to blinks in the visual cortex of every subject and whatever the visual stimulus. The magnitude of the modulation was comparable to visual stimulation. However, blink-related activations lay mostly in the anterior parts of retinotopic visual areas, coding the periphery of the visual field well beyond the extent of our stimuli. Blinks therefore represent an important source of BOLD variations in the visual cortex and a troublesome source of noise since any correlation, even weak, between the distribution of blinks and a tested protocol could trigger artifactual activities. However, the typical signature of blinks along the anterior calcarine and the parieto-occipital sulcus allows identifying, even in the absence of eyetracking, fMRI protocols possibly contaminated by a heterogeneous distribution of blinks.

  11. A New Tool for Assessing Context Conditioning Induced by US-Unpredictability in Humans: The Martians Task Restyled

    Science.gov (United States)

    Meulders, Ann; Vervliet, Bram; Vansteenwegen, Debora; Hermans, Dirk; Baeyens, Frank

    2011-01-01

    Unpredictability of an unconditioned stimulus (US) typically produces context conditioning in animals and humans. We modified the Martians task--a computer game measuring learning of Pavlovian associations through conditioned suppression--for assessing context conditioning in humans. One between-subjects and one within-subjects study are reported.…

  12. A New Tool for Assessing Context Conditioning Induced by US-Unpredictability in Humans: The Martians Task Restyled

    Science.gov (United States)

    Meulders, Ann; Vervliet, Bram; Vansteenwegen, Debora; Hermans, Dirk; Baeyens, Frank

    2011-01-01

    Unpredictability of an unconditioned stimulus (US) typically produces context conditioning in animals and humans. We modified the Martians task--a computer game measuring learning of Pavlovian associations through conditioned suppression--for assessing context conditioning in humans. One between-subjects and one within-subjects study are reported.…

  13. Affective Modulation of the Startle Eyeblink and Postauricular Reflexes in Autism Spectrum Disorder

    Science.gov (United States)

    Dichter, Gabriel S.; Benning, Stephen D.; Holtzclaw, Tia N.; Bodfish, James W.

    2010-01-01

    Eyeblink and postauricular reflexes to standardized affective images were examined in individuals without (n = 37) and with (n = 20) autism spectrum disorders (ASDs). Affective reflex modulation in control participants replicated previous findings. The ASD group, however, showed anomalous reflex modulation patterns, despite similar self-report…

  14. Hippocampal lesions impair performance on a conditional delayed matching and non-matching to position task in the rat.

    Science.gov (United States)

    Sloan, Hazel L; Döbrössy, Màtè; Dunnett, Stephen B

    2006-08-10

    The hippocampus is thought to be involved in a range of cognitive processes, from the ability to acquire new memories, to the ability to learn about spatial relationships. Humans and monkeys with damage to the hippocampus are typically impaired on delayed matching to sample tasks, of which the operant delayed matching to position task (DMTP) is a rat analogue. The reported effects of hippocampal damage on DMTP vary, ranging from delay-dependent deficits to no deficit whatsoever. The present study investigates a novel memory task; the conditional delayed matching/non-matching to position task (CDM/NMTP) in the Skinner box. CDM/NMTP uses the presence of specific stimulus cues to signify whether a particular trial is matching or non-matching in nature. Thus, it incorporates both the task contingencies within one session, and supplements the requirement for remembering the side of the lever in the sample phase with attending to the stimulus and remembering the conditional discrimination for the rule. Rats were trained preoperatively and the effects of bilateral excitotoxic lesions of the hippocampus were examined on postoperative retention of the task. Rats with lesions of the hippocampus incurred a significant impairment on the task that was manifest at all delays intervals. Despite a bias towards matching during training, trials of either type were performed with equivalent accuracy and neither rule was affected differentially by the lesion. This task may prove useful in determining the cognitive roles of a range of brain areas.

  15. Eyeblink rate watching classical Hollywood and post-classical MTV editing styles, in media and non-media professionals.

    Science.gov (United States)

    Andreu-Sánchez, Celia; Martín-Pascual, Miguel Ángel; Gruart, Agnès; Delgado-García, José María

    2017-02-21

    While movie edition creates a discontinuity in audio-visual works for narrative and economy-of-storytelling reasons, eyeblink creates a discontinuity in visual perception for protective and cognitive reasons. We were interested in analyzing eyeblink rate linked to cinematographic edition styles. We created three video stimuli with different editing styles and analyzed spontaneous blink rate in participants (N = 40). We were also interested in looking for different perceptive patterns in blink rate related to media professionalization. For that, of our participants, half (n = 20) were media professionals, and the other half were not. According to our results, MTV editing style inhibits eyeblinks more than Hollywood style and one-shot style. More interestingly, we obtained differences in visual perception related to media professionalization: we found that media professionals inhibit eyeblink rate substantially compared with non-media professionals, in any style of audio-visual edition.

  16. Mindfulness meditation modulates reward prediction errors in the striatum in a passive conditioning task

    Directory of Open Access Journals (Sweden)

    Ulrich eKirk

    2015-02-01

    Full Text Available Reinforcement learning models have demonstrated that phasic activity of dopamine neurons during reward expectation encodes information about the predictability of rewards and cues that predict reward. Evidence indicates that mindfulness-based approaches reduce reward anticipation signal in the striatum to negative and positive incentives suggesting the hypothesis that such training influence basic reward processing. Using a passive conditioning task and fMRI in a group of experienced mindfulness meditators and age-matched controls, we tested the hypothesis that mindfulness meditation influence reward and reward prediction error signals. We found diminished positive and negative prediction error-related blood-oxygen level-dependent (BOLD responses in the putamen in meditators compared with controls. In the meditators, this decrease in striatal BOLD responses to reward prediction was paralleled by increased activity in posterior insula, a primary interoceptive region. Critically, responses in the putamen during early trials of the conditioning procedure (run 1 were elevated in both meditators and controls. These results provide evidence that experienced mindfulness meditators show attenuated reward prediction signals to valenced stimuli, which may be related to interoceptive processes encoded in the posterior insula.

  17. Effect of attention division on movement detection and execution in dual-task conditions

    DEFF Research Database (Denmark)

    Aliakbaryhosseinabadi, Susan; Kamavuako, Ernest Nlandu; Farina, Dario

    2017-01-01

    -invasive electroencephalographic (EEG). Participants were asked to perform a series of cue-based ankle dorsiflexions as the primary task (single task level). In some experimental runs, in addition to the primary task they concurrently attended an auditory oddball paradigm consisting of three tones while they were asked to count...... the number of sequences of special tones (dual task level). EEG signals were recorded from nine channels centered on Cz. Analysis of event-related potential (ERP) signals from Cz confirmed that the oddball task decreased the attention to the ankle dorsiflexion significantly. Furthermore, movement...

  18. Hippocampal Homer1 levels influence motivational behavior in an operant conditioning task.

    Directory of Open Access Journals (Sweden)

    Klaus V Wagner

    Full Text Available Loss of motivation and learning impairments are commonly accepted core symptoms of psychiatric disorders such as depression and schizophrenia. Reward-motivated learning is dependent on the hippocampal formation but the molecular mechanisms that lead to functional incentive motivation in this brain region are still largely unknown. Recent evidence implicates neurotransmission via metabotropic glutamate receptors and Homer1, their interaction partner in the postsynaptic density, in drug addiction and motivational learning. As previous reports mainly focused on the prefrontal cortex and the nucleus accumbens, we now investigated the role of hippocampal Homer1 in operant reward learning in the present study. We therefore tested either Homer1 knockout mice or mice that overexpress Homer1 in the hippocampus in an operant conditioning paradigm. Our results show that deletion of Homer1 leads to a diverging phenotype that either displays an inability to perform the task or outstanding hyperactivity in both learning and motivational sessions. Due to the apparent bimodal distribution of this phenotype, the overall effect of Homer1 deletion in this paradigm is not significantly altered. Overexpression of hippocampal Homer1 did not lead to a significantly altered learning performance in any stage of the testing paradigm, yet may subtly contribute to emerging motivational deficits. Our results indicate an involvement of Homer1-mediated signaling in the hippocampus in motivation-based learning tasks and encourage further investigations regarding the specific molecular underpinnings of the phenotypes observed in this study. We also suggest to cautiously interpret the results of this and other studies regarding the phenotype following Homer1 manipulations in animals, since their behavioral phenotype appears to be highly diverse. Future studies would benefit from larger group sizes that would allow splitting the experimental groups in responders and non-responders.

  19. Imaging tasks scheduling for high-altitude airship in emergency condition based on energy-aware strategy.

    Science.gov (United States)

    Zhimeng, Li; Chuan, He; Dishan, Qiu; Jin, Liu; Manhao, Ma

    2013-01-01

    Aiming to the imaging tasks scheduling problem on high-altitude airship in emergency condition, the programming models are constructed by analyzing the main constraints, which take the maximum task benefit and the minimum energy consumption as two optimization objectives. Firstly, the hierarchy architecture is adopted to convert this scheduling problem into three subproblems, that is, the task ranking, value task detecting, and energy conservation optimization. Then, the algorithms are designed for the sub-problems, and the solving results are corresponding to feasible solution, efficient solution, and optimization solution of original problem, respectively. This paper makes detailed introduction to the energy-aware optimization strategy, which can rationally adjust airship's cruising speed based on the distribution of task's deadline, so as to decrease the total energy consumption caused by cruising activities. Finally, the application results and comparison analysis show that the proposed strategy and algorithm are effective and feasible.

  20. Reusable task-specific ionic liquids for a clean ε-caprolactam synthesis under mild conditions.

    Science.gov (United States)

    Turgis, Raphaël; Estager, Julien; Draye, Micheline; Ragaini, Vittorio; Bonrath, Werner; Lévêque, Jean-Marc

    2010-12-17

    Brønsted-acidic ionic liquids that bear a sulfonic acid group, known as Forbes acids, show a good catalytic activity for the Beckmann rearrangement, used to prepare ε-caprolactam, which is a precursor of Nylon 6. The activity essentially stems from the acidity of the sulfonic acid group. Although these task specific ionic liquids suffer from a high viscosity, this drawback can be circumvented at higher temperatures. A combination of the hydrogen sulfate anion and the sulfonic acid group of the cation is needed to obtain the rearrangement product rapidly under mild conditions. When using an excess of ionic liquid, we postulate that the internal pressure of the ionic medium, generated by the high viscosity and the high number of hydrogen-bonds, is strong enough to contribute to a decrease of the thermodynamic barrier. In accordance with the "Principles of Green Chemistry," we have developed a synthesis of ε-caprolactam that requires no additional chemicals except cyclohexanone oxime and the reusable TSIL.

  1. A less stressful animal model: a conditioned avoidance behaviour task for guineapigs.

    Science.gov (United States)

    Agterberg, Martijn J H; van den Broek, Marloes; Philippens, Ingrid H C H M

    2010-07-01

    In the conventional shuttle box, animals are trained to avoid electric foot-shocks. As a consequence of these stress-inducing foot-shocks the animals become anxious and are difficult to train. The aim of the present study was to avoid the stress-inducing foot-shocks and to develop a fast and reliable conditioned avoidance behaviour task for guineapigs. We examined whether narrowband noises at four different sound levels above hearing threshold could be used as conditioned stimulus (CS). The unconditioned stimulus (UCS) was a stream of air, which was used instead of the conventionally used electric foot-shocks. The animals were initially trained with a CS of 78 dB sound pressure level (SPL). In this initial training, guineapigs learned to detect a narrowband noise of 78 dB SPL. Interestingly, during the first additional training session in which three other sound levels were applied, guineapigs did not immediately generalize the learned response at 78 dB SPL to lower sound levels of 58 and 68 dB SPL. However, in this session a noise level of 88 dB SPL led immediately to a high level of responses. The response latency decreased with increasing sound level, from approximately 7 s at 58 dB SPL to approximately 3 s at 88 dB SPL. The escape latency during the UCS was approximately 0.6 s. The present results demonstrate that after reducing the level of stress guineapigs can acquire a response in only a few sessions and furthermore, although the guineapigs were less anxious, training at sound levels of 78 and 88 dB SPL was influenced by an aversive reaction by the guineapig. The results indicate that this aversive reaction of the guineapig is crucial for the training.

  2. Performing a secondary executive task with affective stimuli interferes with decision making under risk conditions.

    Science.gov (United States)

    Gathmann, Bettina; Pawlikowski, Mirko; Schöler, Tobias; Brand, Matthias

    2014-05-01

    Previous studies demonstrated that executive functions are crucial for advantageous decision making under risk and that therefore decision making is disrupted when working memory capacity is demanded while working on a decision task. While some studies also showed that emotions can affect decision making under risk, it is unclear how affective processing and executive functions predict decision-making performance in interaction. The current experimental study used a between-subjects design to examine whether affective pictures (positive and negative pictures compared to neutral pictures), included in a parallel executive task (working memory 2-back task), have an impact on decision making under risk as assessed by the Game of Dice Task (GDT). Moreover, the performance GDT plus 2-back task was compared to the performance in the GDT without any additional task (GDT solely). The results show that the performance in the GDT differed between groups (positive, negative, neutral, and GDT solely). The groups with affective pictures, especially those with positive pictures in the 2-back task, showed more disadvantageous decisions in the GDT than the groups with neutral pictures and the group performing the GDT without any additional task. However, executive functions moderated the effect of the affective pictures. Regardless of affective influence, subjects with good executive functions performed advantageously in the GDT. These findings support the assumption that executive functions and emotional processing interact in predicting decision making under risk.

  3. Learning an operant conditioning task differentially induces gliogenesis in the medial prefrontal cortex and neurogenesis in the hippocampus.

    Directory of Open Access Journals (Sweden)

    Maximiliano Rapanelli

    Full Text Available Circuit modification associated with learning and memory involves multiple events, including the addition and remotion of newborn cells trough adulthood. Adult neurogenesis and gliogenesis were mainly described in models of voluntary exercise, enriched environments, spatial learning and memory task; nevertheless, it is unknown whether it is a common mechanism among different learning paradigms, like reward dependent tasks. Therefore, we evaluated cell proliferation, neurogenesis, astrogliogenesis, survival and neuronal maturation in the medial prefrontal cortex (mPFC and the hippocampus (HIPP during learning an operant conditioning task. This was performed by using endogenous markers of cell proliferation, and a bromodeoxiuridine (BrdU injection schedule in two different phases of learning. Learning an operant conditioning is divided in two phases: a first phase when animals were considered incompletely trained (IT, animals that were learning the task when they performed between 50% and 65% of the responses, and a second phase when animals were considered trained (Tr, animals that completely learned the task when they reached 100% of the responses with a latency time lower than 5 seconds. We found that learning an operant conditioning task promoted cell proliferation in both phases of learning in the mPFC and HIPP. Additionally, the results presented showed that astrogliogenesis was induced in the medial prefrontal cortex (mPFC in both phases, however, the first phase promoted survival of these new born astrocytes. On the other hand, an increased number of new born immature neurons was observed in the HIPP only in the first phase of learning, whereas, decreased values were observed in the second phase. Finally, we found that neuronal maturation was induced only during the first phase. This study shows for the first time that learning a reward-dependent task, like the operant conditioning, promotes neurogenesis, astrogliogenesis, survival and

  4. Imaging Tasks Scheduling for High-Altitude Airship in Emergency Condition Based on Energy-Aware Strategy

    Directory of Open Access Journals (Sweden)

    Li Zhimeng

    2013-01-01

    Full Text Available Aiming to the imaging tasks scheduling problem on high-altitude airship in emergency condition, the programming models are constructed by analyzing the main constraints, which take the maximum task benefit and the minimum energy consumption as two optimization objectives. Firstly, the hierarchy architecture is adopted to convert this scheduling problem into three subproblems, that is, the task ranking, value task detecting, and energy conservation optimization. Then, the algorithms are designed for the sub-problems, and the solving results are corresponding to feasible solution, efficient solution, and optimization solution of original problem, respectively. This paper makes detailed introduction to the energy-aware optimization strategy, which can rationally adjust airship’s cruising speed based on the distribution of task’s deadline, so as to decrease the total energy consumption caused by cruising activities. Finally, the application results and comparison analysis show that the proposed strategy and algorithm are effective and feasible.

  5. Effects of sleep deprivation on different phases of memory in the rat: dissociation between contextual and tone fear conditioning tasks

    Directory of Open Access Journals (Sweden)

    Vanessa C Rossi

    2014-11-01

    Full Text Available Numerous studies show that sleep deprivation (SD impacts negatively on cognitive processes, including learning and memory. Memory formation encompasses distinct phases of which acquisition, consolidation and retrieval are better known. Previous studies with pre-training SD induced by the platform method have shown impairment in fear conditioning tasks. Nonetheless, pre-training manipulations do not allow the distinction between effects on acquisition and/or consolidation, interfering, ultimately, on recall of/performance in the task. In the present study, animals were first trained in contextual and tone fear conditioning tasks and then submitted to SD with the purpose to evaluate the effect of this manipulation on different stages of the learning process, e.g. in the uptake of (new information during learning, its encoding and stabilization, and the recall of stored memories. Besides, we also investigated the effect of SD in the extinction of fear memory and a possible state-dependent learning induced by this manipulation. For each task (contextual or tone fear conditioning, animals were trained and then distributed into control, not sleep-deprived (CTL and SD groups, the latter being submitted to the modified multiple platform paradigm for 96 h. Subsets of eight rats in each group/experiment were submitted to the test of the tasks, either immediately or at different time intervals after SD. The results indicated that a pre-, but not post-training SD impaired recall in the contextual and tone fear conditioning; b this impairment was not state-dependent; c in the contextual fear conditioning, pre-test SD prevented extinction of the learned task. Overall, these results suggest that SD interferes with acquisition, recall and extinction, but not necessarily with consolidation of emotional memory.

  6. Consideration of Uninterrupted Conditions in Solving the Tasks of Plate Bending by the Finite - Element Method

    Directory of Open Access Journals (Sweden)

    Azaryan N. A.

    2007-06-01

    Full Text Available It is suggested a modification of tetragonal finite - element method, where the tasks of plate bending with taking into accountancy uninterrupted normal efforts or displacements are reduced to quadratic programming ones.

  7. Stress and gender effects on prefrontal cortex oxygenation levels assessed during single and dual-task walking conditions.

    Science.gov (United States)

    Holtzer, Roee; Schoen, Chelsea; Demetriou, Eleni; Mahoney, Jeannette R; Izzetoglu, Meltem; Wang, Cuiling; Verghese, Joe

    2017-03-01

    The ability to walk is critical for functional independence and wellbeing. The pre-frontal cortex (PFC) plays a key role in cognitive control of locomotion, notably under attention-demanding conditions. Factors that influence brain responses to cognitive demands of locomotion, however, are poorly understood. Herein, we evaluated the individual and combined effects of gender and perceived stress on stride velocity and PFC Oxygenated Hemoglobin (HbO2 ) assessed during single and dual-task walking conditions. The experimental paradigm included Normal Walk (NW); Cognitive Interference (Alpha); and Walk-While-Talk (WWT) tasks. An instrumented walkway was used to assess stride velocity in NW and WWT conditions. Functional Near-Infrared-Spectroscopy (fNIRS) was used to quantify PFC HbO2 levels during NW, Alpha and WWT. Perceived task-related stress was evaluated with a single 11-point scale item. Participants were community residing older adults (age = 76.8 ± 6.7 years; %female = 56). Results revealed that higher perceived stress was associated with greater decline in stride velocity from single to dual-task conditions among men. Three-way interactions revealed that gender moderated the effect of perceived stress on changes in HbO2 levels comparing WWT to NW and Alpha. Attenuation in the increase in HbO2 levels, in high compared to low perceived stress levels, from the two single task conditions to WWT was observed only in men. Thus, older men may be more vulnerable to the effect of perceived stress on the change in PFC oxygenation levels across walking conditions that vary in terms of cognitive demands. These findings confer important implications for assessment and treatment of individuals at risk of mobility impairments. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  8. Variability of ICA decomposition may impact EEG signals when used to remove eyeblink artifacts.

    Science.gov (United States)

    Pontifex, Matthew B; Gwizdala, Kathryn L; Parks, Andrew C; Billinger, Martin; Brunner, Clemens

    2017-03-01

    Despite the growing use of independent component analysis (ICA) algorithms for isolating and removing eyeblink-related activity from EEG data, we have limited understanding of how variability associated with ICA uncertainty may be influencing the reconstructed EEG signal after removing the eyeblink artifact components. To characterize the magnitude of this ICA uncertainty and to understand the extent to which it may influence findings within ERP and EEG investigations, ICA decompositions of EEG data from 32 college-aged young adults were repeated 30 times for three popular ICA algorithms. Following each decomposition, eyeblink components were identified and removed. The remaining components were back-projected, and the resulting clean EEG data were further used to analyze ERPs. Findings revealed that ICA uncertainty results in variation in P3 amplitude as well as variation across all EEG sampling points, but differs across ICA algorithms as a function of the spatial location of the EEG channel. This investigation highlights the potential of ICA uncertainty to introduce additional sources of variance when the data are back-projected without artifact components. Careful selection of ICA algorithms and parameters can reduce the extent to which ICA uncertainty may introduce an additional source of variance within ERP/EEG studies.

  9. The relationship between eye-winking tics, frequent eye-blinking and blepharospasm.

    Science.gov (United States)

    Elston, J S; Granje, F C; Lees, A J

    1989-04-01

    A family is reported in which three generations were affected with eye-winking tics and/or blepharospasm. The proband developed eye-winking tics in childhood and then developed excessive blinking progressing to blepharospasm by the age of 21 years. His mother presented with Meige's syndrome and spasmodic torticollis at the age of 59 years; his uncle had blinked excessively from his early forties. His eldest son developed an eye-winking tic with facial grimacing at the age of 8 years, and in another son, a self-limiting period of eye-blinking occurred at the age of 4 years. The recovery cycle of the blink reflex was abnormal in all three generations. Three other children with eye-winking tics have a parent or close relative with frequent eye-blinking or blepharospasm. Five patients with adult-onset blepharospasm or Meige's syndrome are also described who had excessive eye-blinking dating back to childhood. It is suggested that eye-winking tics, frequent blinking and blepharospasm may share common pathophysiological mechanisms; the clinical expression may be age-related.

  10. The influence of dual-task conditions on movement in young adults with and without Down syndrome.

    Science.gov (United States)

    Horvat, M; Croce, R; Tomporowski, P; Barna, M C

    2013-10-01

    This investigation compared spatial and temporal movement parameters of a sample of young adults with Down syndrome (DS) (N=12) and individuals without disabilities (IWD) (N=12) under dual-task conditions. Subjects performed a walking task at a preferred speed in isolation and again while holding a plate and cup, carrying tray and cups, talking on a phone, or buttoning a shirt. Spatial and temporal values were compared using a 2 (group) × 5 (conditions) repeated measures analysis of variance. Analysis of spatial components separately indicated that step length, step width, stride length and stride width revealed significant group and condition interactions (p ≤.01). Temporal components yielded significance in velocity and single-leg support time (p ≤.01). The current results support the notion that along with impairments to qualitative motor skills, individuals with DS are also impaired in higher order executive functioning (EF), as measured by a dual-task paradigm. It was concluded that movements are less efficient and functional in individuals with DS when an additional task is encountered while walking. We theorized that the motor program was sufficient for general locomotion but was not sufficiently developed to allow individuals with DS to modify or alter their movements to changing cognitive conditions that increasingly taxed EF. As gait and balance are trainable in this population, we recommend developing appropriate exercise and motor skill interventions during childhood and adolescents to increase strength, stability, and more "robust" ambulatory motor schema.

  11. Task Experience as a Boundary Condition for the Negative Effects of Irrelevant Information on Learning

    NARCIS (Netherlands)

    G.J. Rop (Gert Jan); M. van Wermeskerken (Margot); J.A. de Nooijer (Jacqueline); P.P.J.L. Verkoeijen (Peter); T.A.J.M. van Gog (Tamara)

    2016-01-01

    textabstractResearch on multimedia learning has shown that learning is hampered when a multimedia message includes extraneous information that is not relevant for the task, because processing the extraneous information uses up scarce attention and working memory resources. However, eye-tracking

  12. Task Experience as a Boundary Condition for the Negative Effects of Irrelevant Information on Learning

    NARCIS (Netherlands)

    G.J. Rop (Gert Jan); M. van Wermeskerken (Margot); J.A. de Nooijer (Jacqueline); P.P.J.L. Verkoeijen (Peter); T.A.J.M. van Gog (Tamara)

    2016-01-01

    textabstractResearch on multimedia learning has shown that learning is hampered when a multimedia message includes extraneous information that is not relevant for the task, because processing the extraneous information uses up scarce attention and working memory resources. However, eye-tracking rese

  13. Metacognitive awareness and the fluency of task-based oral output across planning conditions: The case of Iranian TEFL students

    Directory of Open Access Journals (Sweden)

    Zohreh Seifoori

    2016-01-01

    Full Text Available The present inquiry inspected the impact of metacognitive awareness on the fluency of 114 Iranian TEFL learners’ task-based oral output. The participants in six intact classes were selected from a population of 120 English sophomores based on their scores on proficiency pre-test. The classes were randomly assigned as two tripartite groups of experimental and control participants each embracing three groups of pre-task planners (PTP, on-line task planners (OLP, and pre and on-line task planners (POLP. The fifteen-session metacognitive awareness program in the form of a topic-based listening and speaking course was based on Cotterall's (2000 principles of autonomous learning and three sets of metacognitive strategies, centering learning, arranging and planning learning and evaluating learning (Oxford, 1990. Employing a narrative task type, the researcher collected the data using a 2x3 factorial design with two levels of metacognitive awareness and three levels of planning. It was hypothesized that fluency would improve through metacognitive awareness under various planning conditions. Two-way Repeated Measures and One-way ANOVA analyses of the research data revealed significant fluency gains in all experimental participants compared to the control ones and in the control POLP planners. The findings have pedagogical implications for educators and teachers and highlight the need for strategic investment.

  14. Dynamic spatiotemporal brain analyses of the visual checkerboard task: Similarities and differences between passive and active viewing conditions.

    Science.gov (United States)

    Cacioppo, Stephanie; Weiss, Robin M; Cacioppo, John T

    2016-10-01

    We introduce a new analytic technique for the microsegmentation of high-density EEG to identify the discrete brain microstates evoked by the visual reversal checkerboard task. To test the sensitivity of the present analytic approach to differences in evoked brain microstates across experimental conditions, subjects were instructed to (a) passively view the reversals of the checkerboard (passive viewing condition), or (b) actively search for a target stimulus that may appear at the fixation point, and they were offered a monetary reward if they correctly detected the stimulus (active viewing condition). Results revealed that, within the first 168 ms of a checkerboard presentation, the same four brain microstates were evoked in the passive and active viewing conditions, whereas the brain microstates evoked after 168 ms differed between these two conditions, with more brain microstates elicited in the active than in the passive viewing condition. Additionally, distinctions were found in the active condition between a change in a scalp configuration that reflects a change in microstate and a change in scalp configuration that reflects a change in the level of activation of the same microstate. Finally, the bootstrapping procedure identified that two microstates lacked robustness even though statistical significance thresholds were met, suggesting these microstates should be replicated prior to placing weight on their generalizability across individuals. These results illustrate the utility of the analytic approach and provide new information about the spatiotemporal dynamics of the brain states underlying passive and active viewing in the visual checkerboard task. © 2016 Society for Psychophysiological Research.

  15. Self-reported Quality of ADL Task performance in Persons with Chronic Conditions

    DEFF Research Database (Denmark)

    Nielsen, Kristina Tomra; Wæhrens, Eva Ejlersen

    2016-01-01

    Background: Several studies have indicated that persons with chronic diseases perceive problems related to Activities of Daily Living (ADL), including Personal ADL (PADL) and Instrumental ADL (IADL). However, little is known about how persons with chronic diseases perceive the quality of their ADL...... groups with chronic diseases. Method: Persons with various chronic diseases including rheumatic diseases, cancer, chronic obstructive pulmonary disease and schizophrenia were included in the study. Data related to self-reported quality of ADL task performance were collected from 2007-2015 using the ADL...... in relation to selfreported quality of ADL task performance will be investigated both within and between diagnostic groups. Results and conclusion: Data extraction is in progress. We expect the results of the study to show both similarities and differences in relation to self-reported quality of both personal...

  16. Conditioned discrimination of magnetic inclination in a spatial-orientation arena task by homing pigeons (Columba livia).

    Science.gov (United States)

    Mora, Cordula V; Acerbi, Merissa L; Bingman, Verner P

    2014-12-01

    It has been well established that homing pigeons are able to use the Earth's magnetic field to obtain directional information when returning to their loft and that their magnetic compass is based, at least in part, on the perception of magnetic inclination. Magnetic inclination has also been hypothesized in pigeons and other long-distance navigators, such as sea turtles, to play a role providing positional information as part of a map. Here we developed a behavioral paradigm which allows us to condition homing pigeons to discriminate magnetic inclination cues in a spatial-orientation arena task. Six homing pigeons were required to discriminate in a circular arena between feeders located either in a zone with a close to 0 deg inclination cue or in a zone with a rapidly changing inclination cue (-3 deg to +85 deg when approaching the feeder and +85 deg to -3 deg when moving away from the feeder) to obtain a food reward. The pigeons consistently performed this task above chance level. Control experiments, during which the coils were turned off or the current was running anti-parallel through the double-wound coil system, confirmed that no alternative cues were used by the birds in the discrimination task. The results show that homing pigeons can be conditioned to discriminate differences in magnetic field inclination, enabling investigation into the peripheral and central neural processing of geomagnetic inclination under controlled laboratory conditions.

  17. Task-Oriented Parameter Tuning Based on Priority Condition for Biologically Inspired Robot Application

    Directory of Open Access Journals (Sweden)

    Jaesung Kwon

    2015-01-01

    Full Text Available This work gives a biologically inspired control scheme for controlling a robotic system. Novel adaptive behaviors are observed from humans or animals even in unexpected disturbances or environment changes. This is why they have neural oscillator networks in the spinal cord to yield rhythmic-motor primitives robustly under a changing task. Hence, this work focuses on rhythmic arm movements that can be accomplished in terms of employing a control approach based on an artificial neural oscillator model. The main challenge is to determine various parameters for applying a neural feedback to robotic systems with performing a desired behavior and self-maintaining the entrainment effect. Hence, this work proposes a task-oriented parameter tuning algorithm based on the simulated annealing (SA. This work also illustrates how to technically implement the proposed control scheme exploiting a virtual force and neural feedback. With parameters tuned, it is verified in simulations that a 3-DOF planar robotic arm traces a given trajectory precisely, adapting to uneven external disturbances.

  18. Housing conditions and stimulus females: a robust social discrimination task for studying male rodent social recognition.

    Science.gov (United States)

    Macbeth, Abbe H; Edds, Jennifer Stepp; Young, W Scott

    2009-01-01

    Social recognition (SR) enables rodents to distinguish between familiar and novel conspecifics, largely through individual odor cues. SR tasks utilize the tendency for a male to sniff and interact with a novel individual more than a familiar individual. Many paradigms have been used to study the roles of the neuropeptides oxytocin and vasopressin in SR. However, inconsistencies in results have arisen within similar mouse strains, and across different paradigms and laboratories, making reliable testing of SR difficult. The current protocol details a novel approach that is replicable across investigators and in different strains of mice. We created a protocol that uses gonadally intact, singly housed females presented within corrals to group-housed males. Housing females singly before testing is particularly important for reliable discrimination. This methodology will be useful for studying short-term social memory in rodents, and may also be applicable for longer term studies.

  19. SOLUTION MANAGMET’S TASK INTEGRATED SYSTEM OF UNMANNED AIRCRAFT IN CONDITIONS OF UNCERTAINITY

    Directory of Open Access Journals (Sweden)

    Anvar Hazarkhanov

    2011-03-01

    Full Text Available Abstract. In this article the methods of increase the efficiency of the compensation of indignations of theonboard integrated control systems of Unmanned Aircrafts are considered. On the basis of generalizationthe disadvantages of inertial and satellite navigation systems it was revealed, that as a result of theinsufficient compensation of indignations these systems lose a stable condition. They are exposed to barriersand there is unlimited growth of mistakes in time. For the solution of this actual problem of the onboardintegrated control systems a method of increase the efficiency of the compensation of indignations of nonstationarylinear systems in the conditions of uncertainty with the observer and with the correction bymistake of recovery was suggested. For this purpose the conditions of uncertainty were mathematicallystated, the equations of the onboard integrated control systems were completed, as non-stationary object ofmanagement, the observer with correction by mistake of recovery and a matrix of factor of strengthening ofthe observer are made. As a result the system is asymptotically stable to low-frequency indignations and theaccumulation of an error in time at high-frequency indignations is eliminated.Keywords: a condition of uncertainty, a matrix of factor of strengthening of the observer, iasymptoticalstability, low-frequency and high-frequency indignations, nertial and satellite navigation systems, nonstationarylinear systems, onboard integrated control systems, the observer with a correction by mistake ofrecovery, unmanned aircrafts.

  20. Both Trace and Delay Conditioning of Evaluative Responses Depend on Contingency Awareness

    Science.gov (United States)

    Kattner, Florian; Ellermeier, Wolfgang; Tavakoli, Paniz

    2012-01-01

    Whereas previous evaluative conditioning (EC) studies produced inconsistent results concerning the role of contingency knowledge, there are classical eye-blink conditioning studies suggesting that declarative processes are involved in trace conditioning but not in delay conditioning. In two EC experiments pairing neutral sounds (conditioned…

  1. Aged neuronal nitric oxide knockout mice show preserved olfactory learning in both social recognition and odor-conditioning tasks

    Directory of Open Access Journals (Sweden)

    Bronwen M James

    2015-03-01

    Full Text Available There is evidence for both neurotoxic and neuroprotective roles of nitric oxide (NO in the brain and changes in the expression of the neuronal isoform of nitric oxide synthase (nNOS gene occur during aging. The current studies have investigated potential support for either a neurotoxic or neuroprotective role of NO derived from nNOS in the context of aging by comparing olfactory learning and locomotor function in young compared to old nNOS knockout (nNOS/- and wildtype control mice. Tasks involving social recognition and olfactory conditioning paradigms showed that old nNOS-/-animals had improved retention of learning compared to similar aged wildtype controls. Young nNOS-/- animals showed superior reversal learning to wildtypes in a conditioned learning task, although their performance was weakened with age. Interestingly, whereas young nNOS-/- animals were impaired in long term memory for social odors compared to wildtype controls, in old animals this pattern was reversed, possibly indicating beneficial compensatory changes influencing olfactory memory may occur during aging in nNOS-/- animals. Possibly such compensatory changes may have involved increased NO from other NOS isoforms since the memory deficit in young nNOS-/-animals could be rescued by the NO-donor, molsidomine. Both nNOS-/- and wildtype animals showed an age-associated decline in locomotor activity although young nNOS-/- animals were significantly more active than wildtypes, possibly due to an increased interest in novelty. Overall our findings suggest that lack of NO release via nNOS may protect animals to some extent against age-associated cognitive decline in memory tasks typically involving olfactory and hippocampal regions, but not against declines in reversal learning or locomotor activity.

  2. Time-of-day effect on a food-induced conditioned place preference task in monkeys.

    Science.gov (United States)

    Monclaro, Antonielle V; Sampaio, Ana Cristhina; Ribeiro, Natália B; Barros, Marilia

    2014-02-01

    Time can be an important contextual cue for cognitive performance, with implications for reward-associated learned behaviors such as (drug and food) addiction. So, we analyzed: (1) if marmoset monkeys develop a place preference that is conditioned to previous pairings with a highly-palatable food reward; (2) if the response is strongest when training and testing times match - time stamp effect; and (3) if there is an optimal time of the day (morning vs. afternoon) when this preference occurs - time-of-day effect. Subjects were first habituated to a two-compartment conditioned-place-preference (CPP) box. Then, during six training sessions held either in the morning or afternoon, a mixture of jellybeans and live mealworms was made available in a specific compartment. Marmosets were subsequently tested for preferring the food-paired context at the circadian time that either matched or was different from that of training. Compared to baseline levels, only subjects trained and tested in the afternoon made significantly longer and more frequent visits to the food-paired context and with a shorter latency to first entry. Thus, highly-palatable food rewards induced a CPP response. This behavior was exhibited only when training and testing times overlapped and during a restricted circadian timeframe (afternoon), consistent with a time-stamp and time-of-day effect, respectively. In this case, time may have been an internal circadian contextual cue. Whether due to circadian-mediated oscillations in memory and/or reward processes, such findings may be applied to addiction and other learned behaviors. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Personal environmental control: Effects of pre-set conditions for heating and lighting on personal settings, task performance and comfort experience

    NARCIS (Netherlands)

    Korte, E.M. de; Spiekman, M.; Hoes-van Oeffelen, L.; Zande, B. van der; Vissenberg, G.; Huiskes, G.; Kuijt-Evers, L.F.M.

    2015-01-01

    The effects of pre-set environmental conditions of temperature and lighting on the preferred personal settings, comfort experience and task performance of office workers were investigated in an individually controlled workstation. Twenty subjects performed standardized tasks at a prototype workstati

  4. Personal environmental control: Effects of pre-set conditions for heating and lighting on personal settings, task performance and comfort experience

    NARCIS (Netherlands)

    Korte, E.M. de; Spiekman, M.; Hoes-van Oeffelen, L.; Zande, B. van der; Vissenberg, G.; Huiskes, G.; Kuijt-Evers, L.F.M.

    2015-01-01

    The effects of pre-set environmental conditions of temperature and lighting on the preferred personal settings, comfort experience and task performance of office workers were investigated in an individually controlled workstation. Twenty subjects performed standardized tasks at a prototype workstati

  5. Internship Tasks Associated With CIF Icy Regolith Excavation and Volatile Capture Under Vacuum Conditions

    Science.gov (United States)

    Ballesteros, Erik Nicholas

    2014-01-01

    Understanding the surface and atmosphere of Mars is critical to current and future development of exploration systems. Dealing with the Martian regolith-the top layer of soil-remains a significant challenge, and much research is still needed. Addressing this need, the Cryogenics Test Lab and Granular Mechanics and Regolith Operations Lab at NASA's Kennedy Space Center are partnering to develop an apparatus that utilizes simulated Martian regolith in an analogous atmospheric environment to gather data about how the material behaves when exposed to water vapor. Martian surface temperatures range from 128 K (-145 C) to 308 K (35 C), and the average pressure is approximately 4.5 Torr; which presents an environment where water can potentially exist in vapor, solid or liquid form. And based on prior Mars missions such as the Phoenix Lander, it is known that water-ice exists just below the surface. This test apparatus will attempt to recreate the conditions that contributed to the Martian ice deposits by exposing a sample to water vapor at low pressure and temperature; thereby forming ice inside the simulant via diffusion. From this, we can better understand the properties and behavior of the regolith, and have more knowledge concerning its ability to store water-and subsequently, how to dig up and extract that water-which will be crucial to sample gathering when the first manned Mars mission takes place.

  6. Optimal behavior by rats in a choice task is associated to a persistent conditioned inhibition effect.

    Science.gov (United States)

    Trujano, R Emmanuel; López, Paulina; Rojas-Leguizamón, Maryed; Orduña, Vladimir

    2016-09-01

    When given a choice between an alternative with a low probability of reinforcement and discriminative stimuli, and another with a higher probability of reinforcement and non-discriminative stimuli, pigeons show a clear preference for the former but rats clearly prefer the later. It has been reported that pigeon's suboptimal choice is associated to a diminishing effect of the stimulus correlated with non-reinforcement. In the present paper, we explored the possibility that rats' optimal choice is more strongly influenced than pigeons' by the stimulus associated to non-reinforcement and that the effects of it do not dissipate during training. We trained rats to choose between an alternative with 0.50 probability of reinforcement and discriminative stimuli, and an alternative with 0.75 probability of reinforcement and non-discriminative stimuli. We replicated the strong preference for the optimal alternative. Then, after several sessions of training, we presented summation trials in which both the stimulus associated to reinforcement and the stimulus associated to non-reinforcement were simultaneously presented. The results showed that the stimulus associated to non-reinforcement exerted a strong effect on choice, and, more importantly, that it did not seem to dissipate across training. These results suggest that the strong difference found between pigeons and rats in the suboptimal choice procedure is potentially related to differences in the impact of conditioned inhibitors.

  7. 论CKO的人选素质与职责任务%On Essential Conditions for CKOs and Their Obligations & Tasks

    Institute of Scientific and Technical Information of China (English)

    卢青

    2001-01-01

    This article discusses the essential conditions for a Chief Knowledge Officer (CKO),the competence capability he should possess for his multiple roles and the obligation and tasks he should undertake.

  8. IEA SHC Task 38 'Solar air-conditioning and refrigeration'. Danish participation 2007-2010; IEA SHC Task 38 'Solar air-conditioning and refrigeration'. Dansk deltagelse 2007-2010

    Energy Technology Data Exchange (ETDEWEB)

    Ellehauge, K. (Ellehauge og Kildemoes, Aarhus (Denmark)); Muenster, E. (PlanEnergi, Skoerping (Denmark)); Reinholdt, L. (Teknologisk Institut, Aarhus (Denmark)); Minds, S. (AC-Sun Aps, Horsens (Denmark))

    2011-03-15

    IEA SHC Task 38 'Solar Air-Conditioning and Refrigeration' ran from October 2006 to December 2010. Denmark was represented in the task from January 2007 to December 2010. The aim of the task was to encourage use of solar powered refrigeration and air conditioning systems in particular at residential, commercial and industrial sectors. Furthermore, the aim was to contribute to new research and development activities on new systems and concepts. Solar cooling is an energy efficient way to cool buildings, which can also be used in Denmark as there is a high correlation between solar radiation and the need for air conditioning. Part of the Danish team has also been the company AC Sun which in the period has worked with developing a new and revolutionary thermo-cooling technology. IEA SHC Task 38 Solar Air-Conditioning and Refrigeration was divided into 4 subtask: 1) Subtask A: Pre-engineered systems for residential and small commercial applications 2) Subtask B: Custom-made systems for large non-residential buildings and industrial applications 3) Subtask C: Modelling and fundamental analysis 4) Subtask D: Market transfer activities. The Danish participation consisted of: 1) Ellehauge and Kildemoes (Klaus Ellehauge), project management and overall information. Participated in the subtask A and C and D. 2) AC-Sun (Soeren Minds) participated in subtask A, C and D. 3) PlanEnergi (Ebbe Muenster) participated in subtask B and C. 4) Technological Institute (Lars Reinholdt) participated in subtask A, B and C. The main findings of the task are given in the new handbook that will be published in summer 2011. This report summarises some of the results in Danish and in particular the Danish effort. The Danish project group has provided input to the international reports of the task. A number of the materials prepared by the project are attached as annexes. PlanEnergi was involved in analysis of measurements of the absorption system of 105 kW established year 2007 in

  9. Evidence that Illness-Compatible Cues Are Rewarding in Women Recovered from Anorexia Nervosa: A Study of the Effects of Dopamine Depletion on Eye-Blink Startle Responses

    Science.gov (United States)

    O’Hara, Caitlin B.; Keyes, Alexandra; Renwick, Bethany; Giel, Katrin E.; Campbell, Iain C.; Schmidt, Ulrike

    2016-01-01

    In anorexia nervosa (AN), motivational salience is attributed to illness-compatible cues (e.g., underweight and active female bodies) and this is hypothesised to involve dopaminergic reward circuitry. We investigated the effects of reducing dopamine (DA) transmission on the motivational processing of AN-compatible cues in women recovered from AN (AN REC, n = 17) and healthy controls (HC, n = 15). This involved the acute phenylalanine and tyrosine depletion (APTD) procedure and a startle eye-blink modulation (SEM) task. In a balanced amino acid state, AN REC showed an increased appetitive response (decreased startle potentiation) to illness-compatible cues (underweight and active female body pictures (relative to neutral and non-active cues, respectively)). The HC had an aversive response (increased startle potentiation) to the same illness-compatible stimuli (relative to neutral cues). Importantly, these effects, which may be taken to resemble symptoms observed in the acute stage of illness and healthy behaviour respectively, were not present when DA was depleted. Thus, AN REC implicitly appraised underweight and exercise cues as more rewarding than did HC and the process may, in part, be DA-dependent. It is proposed that the positive motivational salience attributed to cues of emaciation and physical activity is, in part, mediated by dopaminergic reward processes and this contributes to illness pathology. These observations are consistent with the proposal that, in AN, aberrant reward-based learning contributes to the development of habituation of AN-compatible behaviours. PMID:27764214

  10. Modulation of eyeblink and postauricular reflexes during the anticipation and viewing of food images.

    Science.gov (United States)

    Hebert, Karen R; Valle-Inclán, Fernando; Hackley, Steven A

    2015-04-01

    One of the goals of neuroscience research on the reward system is to fractionate its functions into meaningful subcomponents. To this end, the present study examined emotional modulation of the eyeblink and postauricular components of startle in 60 young adults during anticipation and viewing of food images. Appetitive and disgusting photos served as rewards and punishments in a guessing game. Reflexes evoked during anticipation were not influenced by valence, consistent with the prevailing view that startle modulation indexes hedonic impact (liking) rather than incentive salience (wanting). During the slide-viewing period, postauricular reflexes were larger for correct than incorrect feedback, whereas the reverse was true for blink reflexes. Probes were delivered in brief trains, but only the first response exhibited this pattern. The specificity of affective startle modification makes it a valuable tool for studying the reward system. Copyright © 2014 Society for Psychophysiological Research.

  11. Infrared reflectance as an alternative to EMG for measuring prepulse inhibition of startle eyeblink.

    Science.gov (United States)

    Lovelace, Christopher T; Elmore, Wade R; Filion, Diane L

    2006-09-01

    The "gold standard" measure of the human startle eyeblink response is the ocular electromyogram (EMG). However, EMG measurement is not always feasible, as with special populations or during functional neuroimaging. We evaluated an alternative, nonelectrical, noncontact measure that uses infrared (IR) light reflected from the eye. By simultaneously recording IR and EMG during an acoustic prepulse inhibition of startle paradigm, we were able to directly compare the two measures and evaluate the relative reliability and validity of the IR measure as an index of startle response modulation. Although fewer responses were detected using IR than EMG, both measures were equally sensitive to prepulse modulation of response amplitude, latency, and probability. We conclude that when the goal is simply to assess the effects of a prepulse on the startle response, IR reflectance is an adequate alternative to EMG.

  12. Self-ordered pointing and visual conditional associative learning tasks in drug-free schizophrenia spectrum disorder patients

    Directory of Open Access Journals (Sweden)

    Galluzzo Alessandro

    2008-01-01

    Full Text Available Abstract Background There is evidence of a link between schizophrenia and a deficit of working memory, but this has been derived from tasks not specifically developed to probe working memory per se. Our aim was to investigate whether working memory deficits may be detected across different paradigms using the self-ordered pointing task (SOPT and the visual conditional associative learning task (VCALT in patients with schizophrenia spectrum disorders and healthy controls. The current literature suggests deficits in schizophrenia spectrum disorder patients versus healthy controls but these studies frequently involved small samples, broad diagnostic criteria, inclusion of patients on antipsychotic medications, and were not controlled for symptom domains, severity of the disorder, etc. To overcome some of these limitations, we investigated the self-monitoring and conditional associative learning abilities of a numerically representative sample of healthy controls and a group of non-deteriorated, drug-free patients hospitalized for a schizophrenia spectrum disorder with florid, mainly positive psychotic symptoms. Methods Eighty-five patients with a schizophrenia spectrum disorder (DSM-IV-TR diagnosis of schizophrenia (n = 71 or schizophreniform disorder (n = 14 and 80 healthy controls entered the study. The clinical picture was dominated by positive symptoms. The healthy control group had a negative personal and family history of schizophrenia or mood disorder and satisfied all the inclusion and exclusion criteria other than variables related to schizophrenia spectrum disorders. Results Compared to controls, patients had worse performances on SOPT, VCALT and higher SOPT/VCALT ratios, not affected by demographic or clinical variables. ROC curves showed that SOPT, VCALT, and SOPT/VCALT ratio had good accuracy in discriminating patients from controls. The SOPT and VCALT scores were inter-correlated in controls but not in patients. Conclusion The

  13. Fear of falling is associated with prolonged anticipatory postural adjustment during gait initiation under dual-task conditions in older adults.

    Science.gov (United States)

    Uemura, Kazuki; Yamada, Minoru; Nagai, Koutatsu; Tanaka, Buichi; Mori, Shuhei; Ichihashi, Noriaki

    2012-02-01

    Little is known about dynamic balance control under dual-task conditions in older adults with fear of falling (FoF). The purpose of this study was to examine the effect of FoF on anticipatory postural adjustment (APA) during gait initiation under dual-task conditions in older adults. Fifty-seven elderly volunteers (age, 79.2 [6.8] years) from the community participated in this study. Each participant was categorised into either the Fear (n=24) or No-fear (n=33) group on the basis of the presence or absence of FoF. Under single- and dual-task conditions, centre of pressure (COP) data were collected while the participants performed gait initiation trials from a starting position on a force platform. We also performed a 10-m walking test (WT), a timed up & go test (TUG), and a functional reach test (FR). The reaction and APA phases were measured from the COP data. The results showed that under the dual-task condition, the Fear group had significantly longer APA phases than the No-fear group, although no significant differences were observed between the 2 groups in the reaction and APA phases under the single-task condition and in any clinical measurements (WT, TUG, and FR). Our findings suggest that specific deficits in balance control occur in subjects with FoF during gait initiation while dual tasking, even if their physical functions are comparable to subjects without FoF.

  14. Pre-pulse inhibition of the acoustic startle eye-blink in the Göttingen minipig

    DEFF Research Database (Denmark)

    Arnfred, Sidse Marie; Lind, Nanna Marie; Hansen, Axel Kornerup;

    2004-01-01

    by a weak white noise pre-pulse (PP), the interval between the PP and the startle noise stimulus (SNS) determining the degree of inhibition. Aiming at developing a new animal model of schizophrenia, we have investigated the acoustic startle eye-blink and PPI in 10 Göttingen minipigs. The stimuli......Pre-pulse inhibition (PPI) of the startle response is a measure of sensorimotor gating which has been frequently shown to be deficient in schizophrenic patients. In humans it is typically measured as the attenuation of the startle eye-blink reflex EMG when a startle eliciting noise is preceded...... and the block design of the stimulation were similar to paradigms used in human research. Initially the startle habituation across trials and blocks, secondarily the PPI at PP to SNS intervals of 30, 60, 120, 220, 520, 1020 and 2020 ms was investigated. One pig out of ten did not have a startle response...

  15. The effect of a cognitive-motor intervention on voluntary step execution under single and dual task conditions in older adults: a randomized controlled pilot study

    Directory of Open Access Journals (Sweden)

    Pichierri G

    2012-07-01

    Full Text Available Giuseppe Pichierri,1 Amos Coppe,1 Silvio Lorenzetti,2 Kurt Murer,1 Eling D de Bruin11Institute of Human Movement Sciences and Sport, Department of Health Sciences and Technology, ETH Zurich, Switzerland; 2Institute for Biomechanics, Department of Health Sciences and Technology, ETH Zurich, SwitzerlandBackground: This randomized controlled pilot study aimed to explore whether a cognitive-motor exercise program that combines traditional physical exercise with dance video gaming can improve the voluntary stepping responses of older adults under attention demanding dual task conditions.Methods: Elderly subjects received twice weekly cognitive-motor exercise that included progressive strength and balance training supplemented by dance video gaming for 12 weeks (intervention group. The control group received no specific intervention. Voluntary step execution under single and dual task conditions was recorded at baseline and post intervention (Week 12.Results: After intervention between-group comparison revealed significant differences for initiation time of forward steps under dual task conditions (U = 9, P = 0.034, r = 0.55 and backward steps under dual task conditions (U = 10, P = 0.045, r = 0.52 in favor of the intervention group, showing altered stepping levels in the intervention group compared to the control group.Conclusion: A cognitive-motor intervention based on strength and balance exercises with additional dance video gaming is able to improve voluntary step execution under both single and dual task conditions in older adults.Keywords: fall prevention, exercise, dance, video game

  16. Strategic use of reminders in an 'intention offloading' task: Do individuals with autism spectrum conditions compensate for memory difficulties?

    Science.gov (United States)

    Cherkaoui, Mouslim; Gilbert, Sam J

    2017-03-01

    Previous studies have found that individuals with autism spectrum conditions (ASC) can have difficulty remembering to execute delayed intentions. However, in these studies participants were prevented from setting external reminders, whereas the use of such reminders in everyday life is commonplace (e.g. calendars, to-do lists, smartphone alerts). In the present study, 28 participants with ASC and 24 matched neurotypicals performed a task requiring them to remember delayed intentions. In the first phase participants were required to use unaided memory, whereas in the second they had the option to offload their intentions by setting reminders if they wished. Performance of the ASC group was significantly poorer than the neurotypical group in phase 1, and metacognitive evaluations of memory abilities mirrored this. Nevertheless, in the second phase, the ASC group failed to compensate for impaired performance: if anything they set fewer reminders than the neurotypical group. These results indicate that intact explicit metacognitive judgements cannot be assumed to lead directly to the use of compensatory strategies.

  17. The Personality Trait of Intolerance to Uncertainty Affects Behavior in a Novel Computer-Based Conditioned Place Preference Task

    Directory of Open Access Journals (Sweden)

    Milen Radell

    2016-08-01

    Full Text Available Recent work has found that personality factors that confer vulnerability to addiction can also affect learning and economic decision making. One personality trait which has been implicated in vulnerability to addiction is intolerance to uncertainty (IU, i.e. a preference for familiar over unknown (possible better options. In animals, the motivation to obtain drugs is often assessed through conditioned place preference (CPP, which compares preference for contexts where drug reward was previously received. It is an open question whether participants with high IU also show heightened preference for previously-rewarded contexts. To address this question, we developed a novel computer-based CPP task for humans in which participants guide an avatar through a paradigm in which one room contains frequent reward and one contains less frequent reward. Following exposure to both contexts, subjects are assessed for preference to enter the previously-rich and previously-poor room. Individuals with low IU showed little bias to enter the previously-rich room first, and instead entered both rooms at about the same rate. By contrast, those with high IU showed a strong bias to enter the previously-rich room first. This suggests an increased tendency to chase reward in the intolerant group, consistent with previously observed behavior in opioid-addicted individuals. Thus, high IU may represent a pre-existing cognitive bias that provides a mechanism to promote decision-making processes that increase vulnerability to addiction.

  18. Effects of hippocampal state-contingent trial presentation on hippocampus-dependent nonspatial classical conditioning and extinction.

    Science.gov (United States)

    Nokia, Miriam S; Wikgren, Jan

    2014-04-23

    Hippocampal local field potentials are characterized by two mutually exclusive states: one characterized by regular θ oscillations (∼4-8 Hz) and the other by irregular sharp-wave ripples. Presenting stimuli during dominant θ oscillations leads to expedited learning, suggesting that θ indexes a state in which encoding is most effective. However, ripple-contingent training also expedites learning, suggesting that any discrete brain state, much like the external context, can affect learning. We trained adult rabbits in trace eyeblink conditioning, a hippocampus-dependent nonspatial task, followed by extinction. Trials were delivered either in the presence or absence of θ or regardless of hippocampal state. Conditioning in the absence of θ led to more animals learning, although learning was slower compared with a yoked control group. Contrary to expectations, conditioning in the presence of θ did not affect learning. However, extinction was expedited both when it was conducted contingent on θ and when it was conducted in a state contrary to that used to trigger trials during conditioning. Strong phase-locking of hippocampal θ-band responses to the conditioned stimulus early on during conditioning predicted good learning. No such connection was observed during extinction. Our results suggest that any consistent hippocampal oscillatory state can potentially be used to regulate learning. However, the effects depend on the specific state and task at hand. Finally, much like the external environment, the ongoing neural state appears to act as a context for learning and memory retrieval.

  19. A functional approach for research on cognitive control: Analysing cognitive control tasks and their effects in terms of operant conditioning.

    Science.gov (United States)

    Liefooghe, Baptist; De Houwer, Jan

    2016-02-01

    Cognitive control is an important mental ability that is examined using a multitude of cognitive control tasks and effects. The present paper presents the first steps in the elaboration of a functional approach, which aims to uncover the communalities and differences between different cognitive control tasks and their effects. Based on the idea that responses in cognitive control tasks qualify as operant behaviour, we propose to reinterpret cognitive control tasks in terms of operant contingencies and cognitive control effects as instances of moderated stimulus control. We illustrate how our approach can be used to uncover communalities between topographically different cognitive control tasks and can lead to novel questions about the processes underlying cognitive control.

  20. The Mental Health Condition of Manufacturing Front-line Workers: The Interrelationship of Personal Resources, Professional Tasks and Mental Health

    Directory of Open Access Journals (Sweden)

    Zhang Qian

    2017-01-01

    Full Text Available Manufacturing front-line workers were more likely to experience mental health problems. Personal resources and professional tasks were the major factors of workers’ mental health. Therefore, this study was to explore the interrelationship of these three key factors. A questionnaire including the revised Occupational Stress Inventory (OSI-R and the Symptom Checklist (SCL-90 covered 480 manufacturing front-line workers to measure their personal resources, professional tasks and mental health. Results showed that among manufacturing front-line workers, the status of mental health and professional tasks were below the national average level, and the personal resources were relatively deficient as well. Correlation analysis indicated a negative relation between the indicators of mental health and professional tasks (except responsibility, while personal resources and mental health were significantly positive correlation. These findings suggested that personal resources and professional tasks were highly related to mental health in manufacturing front-line workers.

  1. Time Course of the Rabbit's Conditioned Nictitating Membrane Movements during Acquisition, Extinction, and Reacquisition

    Science.gov (United States)

    Kehoe, E. James; Ludvig, Elliot A.; Sutton, Richard S.

    2014-01-01

    The present experiment tested whether or not the time course of a conditioned eyeblink response, particularly its duration, would expand and contract, as the magnitude of the conditioned response (CR) changed massively during acquisition, extinction, and reacquisition. The CR duration remained largely constant throughout the experiment, while CR…

  2. Naloxone induces multiple effects on aversive Pavlovian conditioning in rabbits.

    Science.gov (United States)

    Hernández, L L; Powell, D A

    1983-06-01

    A series of experiments examined the effects of intravenous naloxone treatment on aversive Pavlovian conditioning of eye-blink and heart rate responses, and related unconditioned behaviors, in rabbits. Naloxone treatment before testing attenuated bradycardiac orienting responses to tones used as conditioning stimuli. Naloxone also attenuated conditioned bradycardia when administered either before or after training sessions, but it potentiated conditioned bradycardia during extinction of discriminative conditioning. Naloxone did not influence acquisition or extinction of discriminative eye-blink conditioning or somatic or cardiac responses to shocks used as unconditioned stimuli, but it did decrease locomotor activity. Naloxone treatment immediately after training sessions facilitated acquisition of eye-blink responses. It was concluded that naloxone influences aversive Pavlovian conditioning in more than one way: (a) During training, it appears to alter reception and processing of signals but does not affect subsequent development of somatic responses to the Pavlovian conditioning contingency. (b) After training sessions, naloxone apparently affects consolidation of both somatic and autonomic conditioning. (c) Naloxone also appears to delay extinction of Pavlovian conditioning; this effect may similarly involve changes in a stimulus-processing mechanism or in memory functions, but it apparently does not involve changes in somatomotor responsitivity.

  3. Startling Sweet Temptations: Hedonic Chocolate Deprivation Modulates Experience, Eating Behavior, and Eyeblink Startle

    Science.gov (United States)

    Blechert, Jens; Naumann, Eva; Schmitz, Julian; Herbert, Beate M.; Tuschen-Caffier, Brunna

    2014-01-01

    Many individuals restrict their food intake to prevent weight gain. This restriction has both homeostatic and hedonic effects but their relative contribution is currently unclear. To isolate hedonic effects of food restriction, we exposed regular chocolate eaters to one week of chocolate deprivation but otherwise regular eating. Before and after this hedonic deprivation, participants viewed images of chocolate and images of high-calorie but non-chocolate containing foods, while experiential, behavioral and eyeblink startle responses were measured. Compared to satiety, hedonic deprivation triggered increased chocolate wanting, liking, and chocolate consumption but also feelings of frustration and startle potentiation during the intertrial intervals. Deprivation was further characterized by startle inhibition during both chocolate and food images relative to the intertrial intervals. Individuals who responded with frustration to the manipulation and those who scored high on a questionnaire of impulsivity showed more relative startle inhibition. The results reveal the profound effects of hedonic deprivation on experiential, behavioral and attentional/appetitive response systems and underscore the role of individual differences and state variables for startle modulation. Implications for dieting research and practice as well as for eating and weight disorders are discussed. PMID:24416437

  4. Startling sweet temptations: hedonic chocolate deprivation modulates experience, eating behavior, and eyeblink startle.

    Science.gov (United States)

    Blechert, Jens; Naumann, Eva; Schmitz, Julian; Herbert, Beate M; Tuschen-Caffier, Brunna

    2014-01-01

    Many individuals restrict their food intake to prevent weight gain. This restriction has both homeostatic and hedonic effects but their relative contribution is currently unclear. To isolate hedonic effects of food restriction, we exposed regular chocolate eaters to one week of chocolate deprivation but otherwise regular eating. Before and after this hedonic deprivation, participants viewed images of chocolate and images of high-calorie but non-chocolate containing foods, while experiential, behavioral and eyeblink startle responses were measured. Compared to satiety, hedonic deprivation triggered increased chocolate wanting, liking, and chocolate consumption but also feelings of frustration and startle potentiation during the intertrial intervals. Deprivation was further characterized by startle inhibition during both chocolate and food images relative to the intertrial intervals. Individuals who responded with frustration to the manipulation and those who scored high on a questionnaire of impulsivity showed more relative startle inhibition. The results reveal the profound effects of hedonic deprivation on experiential, behavioral and attentional/appetitive response systems and underscore the role of individual differences and state variables for startle modulation. Implications for dieting research and practice as well as for eating and weight disorders are discussed.

  5. (-)-Bornyl acetate induces autonomic relaxation and reduces arousal level after visual display terminal work without any influences of task performance in low-dose condition.

    Science.gov (United States)

    Matsubara, Eri; Fukagawa, Mio; Okamoto, Tsuyoshi; Ohnuki, Koichiro; Shimizu, Kuniyoshi; Kondo, Ryuichiro

    2011-04-01

    (-)-Bornyl acetate is the main volatile constituent in numerous conifer oils and has a camphoraceous, pine-needle-like odor. It is frequently used as the conifer needle composition in soap, bath products, room sprays, and pharmaceutical products. However, the psychophysiological effects of (-)-bornyl acetate remained unclear. We investigated the effects of breathing air mixed with (-)-bornyl acetate at different doses (low-dose and high-dose conditions) on the individuals during and after VDT (visual display terminal) work using a visual discrimination task. The amounts of (-)-bornyl acetate through our odorant delivery system for 40 min were 279.4 µg in the low-dose and 716.3 µg in the high-dose (-)-bornyl acetate condition. (-)-Bornyl acetate induced changes of autonomic nervous system for relaxation and reduced arousal level after VDT work without any influences of task performance in low-dose condition, but not in high-dose condition.

  6. The "Reading the Mind in Films" Task [Child Version]: Complex Emotion and Mental State Recognition in Children with and without Autism Spectrum Conditions

    Science.gov (United States)

    Golan, Ofer; Baron-Cohen, Simon; Golan, Yael

    2008-01-01

    Children with autism spectrum conditions (ASC) have difficulties recognizing others' emotions. Research has mostly focused on "basic" emotion recognition, devoid of context. This study reports the results of a new task, assessing recognition of "complex" emotions and mental states in social contexts. An ASC group (n = 23) was compared to a general…

  7. Housing conditions affect rat responses to two types of ambiguity in a reward-reward discrimination cognitive bias task.

    Science.gov (United States)

    Parker, Richard M A; Paul, Elizabeth S; Burman, Oliver H P; Browne, William J; Mendl, Michael

    2014-11-01

    Decision-making under ambiguity in cognitive bias tasks is a promising new indicator of affective valence in animals. Rat studies support the hypothesis that animals in a negative affective state evaluate ambiguous cues negatively. Prior automated operant go/go judgement bias tasks have involved training rats that an auditory cue of one frequency predicts a Reward and a cue of a different frequency predicts a Punisher (RP task), and then measuring whether ambiguous cues of intermediate frequency are judged as predicting reward ('optimism') or punishment ('pessimism'). We investigated whether an automated Reward-Reward (RR) task yielded similar results to, and was faster to train than, RP tasks. We also introduced a new ambiguity test (simultaneous presentation of the two training cues) alongside the standard single ambiguous cue test. Half of the rats experienced an unpredictable housing treatment (UHT) designed to induce a negative state. Control rats were relatively 'pessimistic', whilst UHT rats were quicker, but no less accurate, in their responses in the RR test, and showed less anxiety-like behaviour in independent tests. A possible reason for these findings is that rats adapted to and were stimulated by UHT, whilst control rats in a predictable environment were more sensitive to novelty and change. Responses in the new ambiguity test correlated positively with those in single ambiguous cue tests, and may provide a measure of attention bias. The RR task was quicker to train than previous automated RP tasks. Together, they could be used to disentangle how reward and punishment processes underpin affect-induced cognitive biases.

  8. The reliability of the quantitative timed up and go test (QTUG) measured over five consecutive days under single and dual-task conditions in community dwelling older adults.

    Science.gov (United States)

    Smith, Erin; Walsh, Lorcan; Doyle, Julie; Greene, Barry; Blake, Catherine

    2016-01-01

    The timed up and go (TUG) test is a commonly used assessment in older people with variations including the addition of a motor or cognitive dual-task, however in high functioning older adults it is more difficult to assess change. The quantified TUG (QTUG) uses inertial sensors to detect test and gait parameters during the test. If it is to be used in the longitudinal assessment of older adults, it is important that we know which parameters are reliable and under which conditions. This study aims to examine the relative reliability of the QTUG over five consecutive days under single, motor and cognitive dual-task conditions. Twelve community dwelling older adults (10 females, mean age 74.17 (3.88)) performed the QTUG under three conditions for five consecutive days. The relative reliability of each of the gait parameters was assessed using intra-class correlation coefficient (ICC 3,1) and standard error of measurement (SEM). Five of the measures demonstrated excellent reliability (ICC>0.70) under all three conditions (time to complete test, walk time, number of gait cycles, number of steps and return from turn time). Measures of variability and turn derived parameters demonstrated weak reliability under all three conditions (ICC=0.05-0.49). For the most reliable parameters under single-task conditions, the addition of a cognitive task resulted in a reduction in reliability suggesting caution when interpreting results under these conditions. Certain sensor derived parameters during the QTUG test may provide an additional resource in the longitudinal assessment of older people and earlier identification of falls risk.

  9. SIMULATION OF CARS ACCUMULATION PROCESSES FOR SOLVING TASKS OF OPERATIONAL PLANNING IN CONDITIONS OF INITIAL INFORMATION UNCERTAINTY

    Directory of Open Access Journals (Sweden)

    О. A. Tereshchenko

    2017-06-01

    Full Text Available Purpose. The article highlights development of the methodological basis for simulation the processes of cars accumulation in solving operational planning problems under conditions of initial information uncertainty for assessing the sustainability of the adopted planning scenario and calculating the associated technological risks. Methodology. The solution of the problem under investigation is based on the use of general scientific approaches, the apparatus of probability theory and the theory of fuzzy sets. To achieve this purpose, the factors influencing the entropy of operational plans are systematized. It is established that when planning the operational work of railway stations, sections and nodes, the most significant factors that cause uncertainty in the initial information are: a external conditions with respect to the railway ground in question, expressed by the uncertainty of the timing of cars arrivals; b external, hard-to-identify goals for the functioning of other participants in the logistics chain (primarily customers, expressed by the uncertainty of the completion time with the freight cars. These factors are suggested to be taken into account in automated planning through statistical analysis – the establishment and study of the remaining time (prediction errors. As a result, analytical dependencies are proposed for rational representation of the probability density functions of the time residual distribution in the form of point, piecewise-defined and continuous analytic models. The developed models of cars accumulation, the application of which depends on the identified states of the predicted incoming car flow to the accumulation system, are presented below. In addition, the last proposed model is a general case of models of accumulation processes with an arbitrary level of reliability of the initial information for any structure of the incoming flow of cars. In conclusion, a technique for estimating the results of

  10. Substitution of prescribing tasks from doctors to nurses: an international expert survey on forces, conditions and jurisdictional control.

    NARCIS (Netherlands)

    Kroezen, M.; Francke, A.L.; Groenewegen, P.P.; Dijk, L. van

    2011-01-01

    Background: Nurse prescribing is highly relevant in the current climate of cost containment and task substitution in health care, and is being introduced in a growing number of countries. However, international comparisons are scarce. This survey aims to provide a comprehensive and recent overview o

  11. Metacognitive Awareness and the Fluency of Task-Based Oral Output across Planning Conditions: The Case of Iranian TEFL Students

    Science.gov (United States)

    Seifoori, Zohreh

    2016-01-01

    The present inquiry inspected the impact of metacognitive awareness on the fluency of 114 Iranian TEFL learners' task-based oral output. The participants in six intact classes were selected from a population of 120 English sophomores based on their scores on proficiency pre-test. The classes were randomly assigned as two tripartite groups of…

  12. Adolescent and adult rats differ in the amnesic effects of acute ethanol in two hippocampus-dependent tasks: Trace and contextual fear conditioning.

    Science.gov (United States)

    Hunt, Pamela S; Barnet, Robert C

    2016-02-01

    Experience-produced deficits in trace conditioning and context conditioning have been useful tools for examining the role of the hippocampus in learning. It has also been suggested that learning in these tasks is especially vulnerable to neurotoxic effects of alcohol during key developmental periods such as adolescence. In five experiments we systematically examined the presence and source of age-dependent vulnerability to the memory-disrupting effects of acute ethanol in trace conditioning and contextual fear conditioning. In Experiment 1a pre-training ethanol disrupted trace conditioning more strongly in adolescent (postnatal day, PD30-35) than adult rats (PD65-75). In Experiment 1b when pre-training ethanol was accompanied by pre-test ethanol no deficit in trace conditioning was observed in adolescents, suggesting that state-dependent retrieval failure mediated ethanol's disruption of trace conditioning at this age. Experiment 2a and b examined the effect of ethanol pretreatment on context conditioning. Here, adult but not adolescent rats were impaired in conditioned freezing to context cues. Experiment 2c explored state-dependency of this effect. Pre-training ethanol continued to disrupt context conditioning in adults even when ethanol was also administered prior to test. Collectively these findings reveal clear age-dependent and task-dependent vulnerabilities in ethanol's disruptive effects on hippocampus-dependent memory. Adolescents were more disrupted by ethanol in trace conditioning than adults, and adults were more disrupted by ethanol in context conditioning than adolescents. We suggest that adolescents may be more susceptible to changes in internal state (state-dependent retrieval failure) than adults and that ethanol disrupted performance in trace and context conditioning through different mechanisms. Relevance of these findings to theories of hippocampus function is discussed.

  13. Purkinje cell activity during classical conditioning with different conditional stimuli explains central tenet of Rescorla–Wagner model [corrected].

    Science.gov (United States)

    Rasmussen, Anders; Zucca, Riccardo; Johansson, Fredrik; Jirenhed, Dan-Anders; Hesslow, Germund

    2015-11-10

    A central tenet of Rescorla and Wagner's model of associative learning is that the reinforcement value of a paired trial diminishes as the associative strength between the presented stimuli increases. Despite its fundamental importance to behavioral sciences, the neural mechanisms underlying the model have not been fully explored. Here, we present findings that, taken together, can explain why a stronger association leads to a reduced reinforcement value, within the context of eyeblink conditioning. Specifically, we show that learned pause responses in Purkinje cells, which trigger adaptively timed conditioned eyeblinks, suppress the unconditional stimulus (US) signal in a graded manner. Furthermore, by examining how Purkinje cells respond to two distinct conditional stimuli and to a compound stimulus, we provide evidence that could potentially help explain the somewhat counterintuitive overexpectation phenomenon, which was derived from the Rescorla-Wagner model.

  14. 6-Hydroxydopamine and radiofrequency lesions of the lateral entorhinal cortex facilitate an operant appetitive conditioning task in mice.

    Science.gov (United States)

    Gauthier, M; Soumireu-Mourat, B

    1981-07-02

    The entorhinal cortex seems heterogeneous as dopaminergic terminals are present only in the anterior part of the lateral entorhinal cortex. In order to clarify the interaction of this cortex with the hippocampus in memory processes, the effects of either 6-hydroxydopamine or radiofrequency bilateral lesions were compared. Both lesions enhance the retention of a Skinner task with continuous reinforcement schedule. Involvement of dopamine in memory processes is discussed.

  15. Positive priming and intentional binding: eye-blink rate predicts reward information effects on the sense of agency.

    Science.gov (United States)

    Aarts, Henk; Bijleveld, Erik; Custers, Ruud; Dogge, Myrthel; Deelder, Merel; Schutter, Dennis; Haren, Neeltje E M van

    2012-01-01

    Human society is strongly rooted in people's experiences of agency; that is, the pervasive feeling that one engages in voluntary behavior and causes one's own actions and resulting outcomes. Rewards and positive affect play an important role in the control of voluntary action. However, the role of positive reward signals in the sense of agency is poorly understood. This study examined effects of reward-related information on the sense of agency by employing the intentional binding paradigm. This paradigm measures the extent to which actions and their effects subjectively shift together across time, reflecting a crucial component of people's sense of agency. Results showed that intentional binding is stronger when participants are primed with reward-related information via brief exposure to positive pictures. Interestingly, this positive priming effect was moderated by baseline eye-blink rates (an indirect marker of striatal dopaminergic functioning); reward-related information increased intentional binding mainly for participants displaying higher baseline eye-blink rates. These findings suggest a possible role for striatal dopamine activity in the process by which reward-related information shapes the way people see themselves as agents.

  16. Eyelid contour detection and tracking for startle research related eye-blink measurements from high-speed video records.

    Science.gov (United States)

    Bernard, Florian; Deuter, Christian Eric; Gemmar, Peter; Schachinger, Hartmut

    2013-10-01

    Using the positions of the eyelids is an effective and contact-free way for the measurement of startle induced eye-blinks, which plays an important role in human psychophysiological research. To the best of our knowledge, no methods for an efficient detection and tracking of the exact eyelid contours in image sequences captured at high-speed exist that are conveniently usable by psychophysiological researchers. In this publication a semi-automatic model-based eyelid contour detection and tracking algorithm for the analysis of high-speed video recordings from an eye tracker is presented. As a large number of images have been acquired prior to method development it was important that our technique is able to deal with images that are recorded without any special parametrisation of the eye tracker. The method entails pupil detection, specular reflection removal and makes use of dynamic model adaption. In a proof-of-concept study we could achieve a correct detection rate of 90.6%. With this approach, we provide a feasible method to accurately assess eye-blinks from high-speed video recordings.

  17. Effects of Ginsenoside Rg1 on Learning and Memory in a Reward-directed Instrumental Conditioning Task in Chronic Restraint Stressed Rats.

    Science.gov (United States)

    Kezhu, Wang; Pan, Xu; Cong, Lu; Liming, Dong; Beiyue, Zhang; Jingwei, Lu; Yanyan, Yang; Xinmin, Liu

    2017-01-01

    Ginsenoside Rg1 is one of the major active ingredients of Panax ginseng and has showed notable improving learning and memory effects in several behavioral tasks, such as water maze, shuttle-box, and step-through, based on avoidance. However, there was no report about the role of Rg1 on the performance of reward-directed instrumental conditioning, which could reflect the adaptive capacity to ever-changing environments. Thus, in this study, the reward devaluation test and conditional visual discrimination task were conducted to study the ameliorating effects of Rg1 on cognitive deficits, especially the loss of adaptation capacity in chronic restraint stress (CRS) rat model. Our results showed that rat subjected to CRS became insensitive to the changes in outcome value, and it significantly harmed the rat's performance in conditional visual discrimination task. Moreover, the levels of BDNF, TrkB, and Erk phosphorylation were decreased in the prefrontal cortex of CRS rats. However, these changes were effectively reversed by Rg1 (5 and 10 mg/kg, i.p.). Therefore, it demonstrated that Rg1 has a good ability to improve learning and memory and also ameliorate impaired adaptive capacity induced by CRS. This amelioration effect of Rg1 might be mediated partially by BDNF/TrkB/Erk pathway in prefrontal cortex. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  18. Neural congruency effects in the multi-source interference task vanish in healthy youth after controlling for conditional differences in mean RT.

    Science.gov (United States)

    Kim, Kamin; Carp, Joshua; Fitzgerald, Kate D; Taylor, Stephan F; Weissman, Daniel H

    2013-01-01

    According to the conflict monitoring model of cognitive control, reaction time (RT) in distracter interference tasks (e.g., the Stroop task) is a more precise index of response conflict than stimulus congruency (incongruent vs. congruent). The model therefore predicts that RT should be a reliable predictor of activity in regions of the posterior medial frontal cortex (pMFC) that are posited to detect response conflict. In particular, pMFC activity should be (a) greater in slow-RT than in fast-RT trials within a given task condition (e.g., congruent) and (b) equivalent in RT-matched trials from different conditions (i.e., congruent and incongruent trials). Both of these effects have been observed in functional magnetic resonance imaging (MRI) studies of adults. However, neither effect was observed in a recent study of healthy youth, suggesting that (a) the model does not accurately describe the relationship between RT and pMFC activity in this population or (b) the recent study was characterized by high variability due to a relatively small sample size. To distinguish between these possibilities, we asked a relatively large group of healthy youth (n = 28) to perform a distracter interference task - the multi-source interference task (MSIT) - while we recorded their brain activity with functional MRI. In this relatively large sample, both of the model's predictions were confirmed. We conclude that the model accurately describes the relationship between pMFC activity and RT in healthy youth, but that additional research is needed to determine whether processes unrelated to response conflict contribute to this relationship.

  19. Neural congruency effects in the multi-source interference task vanish in healthy youth after controlling for conditional differences in mean RT.

    Directory of Open Access Journals (Sweden)

    Kamin Kim

    Full Text Available According to the conflict monitoring model of cognitive control, reaction time (RT in distracter interference tasks (e.g., the Stroop task is a more precise index of response conflict than stimulus congruency (incongruent vs. congruent. The model therefore predicts that RT should be a reliable predictor of activity in regions of the posterior medial frontal cortex (pMFC that are posited to detect response conflict. In particular, pMFC activity should be (a greater in slow-RT than in fast-RT trials within a given task condition (e.g., congruent and (b equivalent in RT-matched trials from different conditions (i.e., congruent and incongruent trials. Both of these effects have been observed in functional magnetic resonance imaging (MRI studies of adults. However, neither effect was observed in a recent study of healthy youth, suggesting that (a the model does not accurately describe the relationship between RT and pMFC activity in this population or (b the recent study was characterized by high variability due to a relatively small sample size. To distinguish between these possibilities, we asked a relatively large group of healthy youth (n = 28 to perform a distracter interference task - the multi-source interference task (MSIT - while we recorded their brain activity with functional MRI. In this relatively large sample, both of the model's predictions were confirmed. We conclude that the model accurately describes the relationship between pMFC activity and RT in healthy youth, but that additional research is needed to determine whether processes unrelated to response conflict contribute to this relationship.

  20. Storage of a naturally acquired conditioned response is impaired in patients with cerebellar degeneration.

    Science.gov (United States)

    Thieme, Andreas; Thürling, Markus; Galuba, Julia; Burciu, Roxana G; Göricke, Sophia; Beck, Andreas; Aurich, Volker; Wondzinski, Elke; Siebler, Mario; Gerwig, Marcus; Bracha, Vlastislav; Timmann, Dagmar

    2013-07-01

    Previous findings suggested that the human cerebellum is involved in the acquisition but not the long-term storage of motor associations. The finding of preserved retention in cerebellar patients was fundamentally different from animal studies which show that both acquisition and retention depends on the integrity of the cerebellum. The present study investigated whether retention had been preserved because critical regions of the cerebellum were spared. Visual threat eye-blink responses, that is, the anticipatory closure of the eyes to visual threats, have previously been found to be naturally acquired conditioned responses. Because acquisition is known to take place in very early childhood, visual threat eye-blink responses can be used to test retention in patients with adult onset cerebellar disease. Visual threat eye-blink responses were tested in 19 adult patients with cerebellar degeneration, 27 adult patients with focal cerebellar lesions due to stroke, 24 age-matched control subjects, and 31 younger control subjects. High-resolution structural magnetic resonance images were acquired in patients to perform lesion-symptom mapping. Voxel-based morphometry was performed in patients with cerebellar degeneration, and voxel-based lesion-symptom mapping in patients with focal disease. Visual threat eye-blink responses were found to be significantly reduced in patients with cerebellar degeneration. Visual threat eye-blink responses were also reduced in patients with focal disease, but to a lesser extent. Visual threat eye-blink responses declined with age. In patients with cerebellar degeneration the degree of cerebellar atrophy was positively correlated with the reduction of conditioned responses. Voxel-based morphometry showed that two main regions within the superior and inferior parts of the posterior cerebellar cortex contributed to expression of visual threat eye-blink responses bilaterally. Involvement of the more inferior parts of the posterior lobe was

  1. An Analysis of Early vs. Later Responses on a Divergent Production Task across Three Time Press Conditions.

    Science.gov (United States)

    Johns, Gregg A.; Morse, Linda W.; Morse, David T.

    2001-01-01

    This study examined the effects of three time-press and three creative-prompt conditions on early vs. later trial originality scores for three divergent production stimuli with 91 undergraduate students. Findings indicated a higher frequency of originality scores for the latter portions of trials for all time-press and prompting conditions.…

  2. A cognitive-motor intervention using a dance video game to enhance foot placement accuracy and gait under dual task conditions in older adults: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Pichierri Giuseppe

    2012-12-01

    Full Text Available Abstract Background Computer-based interventions have demonstrated consistent positive effects on various physical abilities in older adults. This study aims to compare two training groups that achieve similar amounts of strength and balance exercise where one group receives an intervention that includes additional dance video gaming. The aim is to investigate the different effects of the training programs on physical and psychological parameters in older adults. Methods Thirty-one participants (mean age ± SD: 86.2 ± 4.6 years, residents of two Swiss hostels for the aged, were randomly assigned to either the dance group (n = 15 or the control group (n = 16. The dance group absolved a twelve-week cognitive-motor exercise program twice weekly that comprised progressive strength and balance training supplemented with additional dance video gaming. The control group performed only the strength and balance exercises during this period. Outcome measures were foot placement accuracy, gait performance under single and dual task conditions, and falls efficacy. Results After the intervention between-group comparison revealed significant differences for gait velocity (U = 26, P = .041, r = .45 and for single support time (U = 24, P = .029, r = .48 during the fast walking dual task condition in favor of the dance group. No significant between-group differences were observed either in the foot placement accuracy test or in falls efficacy. Conclusions There was a significant interaction in favor of the dance video game group for improvements in step time. Significant improved fast walking performance under dual task conditions (velocity, double support time, step length was observed for the dance video game group only. These findings suggest that in older adults a cognitive-motor intervention may result in more improved gait under dual task conditions in comparison to a traditional strength and balance exercise program

  3. Functional disconnection of the substantia nigra pars compacta from the pedunculopontine nucleus impairs learning of a conditioned avoidance task.

    Science.gov (United States)

    Bortolanza, Mariza; Wietzikoski, Evellyn C; Boschen, Suelen L; Dombrowski, Patricia A; Latimer, Mary; Maclaren, Duncan A A; Winn, Philip; Da Cunha, Claudio

    2010-09-01

    The pedunculopontine tegmental nucleus (PPTg) targets nuclei in the basal ganglia, including the substantia nigra pars compacta (SNc), in which neuronal loss occurs in Parkinson's disease, a condition in which patients show cognitive as well as motor disturbances. Partial loss and functional abnormalities of neurons in the PPTg are also associated with Parkinson's disease. We hypothesized that the interaction of PPTg and SNc might be important for cognitive impairments and so investigated whether disrupting the connections between the PPTg and SNc impaired learning of a conditioned avoidance response (CAR) by male Wistar rats. The following groups were tested: PPTg unilateral; SNc unilateral; PPTg-SNc ipsilateral (ipsilateral lesions in PPTg and SNc); PPTg-SNc contralateral (contralateral lesions in PPTg and SNc); sham lesions (of each type). SNc lesions were made with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine HCl (MPTP, 0.6micromol); PPTg lesions with ibotenate (24nmol). After recovery, all rats underwent 50-trial sessions of 2-way active avoidance conditioning for 3 consecutive days. Rats with unilateral lesions in PPTg or SNc learnt this, however rats with contralateral (but not ipsilateral) combined lesions in both structures presented no sign of learning. This effect was not likely to be due to sensorimotor impairment because lesions did not affect reaction time to the tone or footshock during conditioning. However, an increased number of non-responses were observed in the rats with contralateral lesions. The results support the hypothesis that a functional interaction between PPTg and SNc is needed for CAR learning and performance.

  4. Pre-test metyrapone impairs memory recall in fear conditioning tasks: lack of interaction with β-adrenergic activity

    Science.gov (United States)

    Careaga, Mariella B. L.; Tiba, Paula A.; Ota, Simone M.; Suchecki, Deborah

    2015-01-01

    Cognitive processes, such as learning and memory, are essential for our adaptation to environmental changes and consequently for survival. Numerous studies indicate that hormones secreted during stressful situations, such as glucocorticoids (GCs), adrenaline and noradrenaline, regulate memory functions, modulating aversive memory consolidation and retrieval, in an interactive and complementary way. Thus, the facilitatory effects of GCs on memory consolidation as well as their suppressive effects on retrieval are substantially explained by this interaction. On the other hand, low levels of GCs are also associated with negative effects on memory consolidation and retrieval and the mechanisms involved are not well understood. The present study sought to investigate the consequences of blocking the rise of GCs on fear memory retrieval in multiple tests, assessing the participation of β-adrenergic signaling on this effect. Metyrapone (GCs synthesis inhibitor; 75 mg/kg), administered 90 min before the first test of contextual or tone fear conditioning (TFC), negatively affected animals’ performances, but this effect did not persist on a subsequent test, when the conditioned response was again expressed. This result suggested that the treatment impaired fear memory retrieval during the first evaluation. The administration immediately after the first test did not affect the animals’ performances in contextual fear conditioning (CFC), suggesting that the drug did not interfere with processes triggered by memory reactivation. Moreover, metyrapone effects were independent of β-adrenergic signaling, since concurrent administration with propranolol (2 mg/kg), a β-adrenergic antagonist, did not modify the effects induced by metyrapone alone. These results demonstrate that pre-test metyrapone administration led to negative effects on fear memory retrieval and this action was independent of a β-adrenergic signaling. PMID:25784866

  5. Pre-test metyrapone impairs memory recall in fear conditioning tasks: lack of interaction with β-adrenergic activity

    Directory of Open Access Journals (Sweden)

    Mariella B.L. Careaga

    2015-03-01

    Full Text Available Cognitive processes, such as learning and memory, are essential for our adaptation to environmental changes and consequently for survival. Numerous studies indicate that hormones secreted during stressful situations, such as glucocorticoids (GCs, adrenaline and noradrenaline, regulate memory functions, modulating aversive memory consolidation and retrieval, in an interactive and complementary way. Thus, the facilitatory effects of GCs on memory consolidation as well as their suppressive effects on retrieval are substantially explained by this interaction. On the other hand, low levels of GCs are also associated with negative effects on memory consolidation and retrieval and the mechanisms involved are not well understood. The present study sought to investigate the consequences of blocking the rise of GCs on fear memory retrieval in multiple tests, assessing the participation of β-adrenergic signaling on this effect. Metyrapone (GCs synthesis inhibitor, administered 90 min before the first test of contextual or auditory fear conditioning, negatively affected animals’ performances, but this effect did not persist on a subsequent test, when the conditioned response was again expressed. This result suggested that the treatment impaired fear memory retrieval during the first evaluation. The administration immediately after the first test did not affect the animals’ performances in contextual fear conditioning, suggesting that the drug did not interfere with processes triggered by memory reactivation. Moreover, metyrapone effects were independent of β-adrenergic signaling, since concurrent administration with propranolol, a β-adrenergic antagonist, did not modify the effects induced by metyrapone alone. These results demonstrate that pre-test metyrapone administration led to negative effects on fear memory retrieval and this action was independent of a β-adrenergic signaling.

  6. Task reports on developing techniques for scattering by 3D composite structures and to generate new solutions in diffraction theory using higher order boundary conditions

    Science.gov (United States)

    Volakis, John L.

    1991-01-01

    There are two tasks described in this report. First, an extension of a two dimensional formulation is presented for a three dimensional body of revolution. A Fourier series expansion of the vector electric and magnetic fields is employed to reduce the dimensionality of the system, and an exact boundary condition is employed to terminate the mesh. The mesh termination boundary is chosen such that it leads to convolutional boundary operators for low O(n) memory demand. Second, rigorous uniform geometrical theory of diffraction (UTD) diffraction coefficients are presented for a coated convex cylinder simulated with generalized impedance boundary conditions. Ray solutions are obtained which remain valid in the transition region and reduce uniformly those in the deep lit and shadow regions. A uniform asymptotic solution is also presented for observations in the close vicinity of the cylinder.

  7. EFFORTS Sub-task report on task 4.1: Experimental Techniques

    DEFF Research Database (Denmark)

    Andreasen, Jan Lasson; Bay, Niels

    1998-01-01

    Task 4.1 is a sub-task of task 4: Physical modelling validation. In sub-task 4.1 the existing experimental techniques has been conditioned to the tasks ahead in physical modelling.......Task 4.1 is a sub-task of task 4: Physical modelling validation. In sub-task 4.1 the existing experimental techniques has been conditioned to the tasks ahead in physical modelling....

  8. High versus low fat/sugar food affects the behavioral, but not the cortisol response of marmoset monkeys in a conditioned-place-preference task.

    Science.gov (United States)

    Duarte, R B M; Patrono, E; Borges, A C; Tomaz, C; Ventura, R; Gasbarri, A; Puglisi-Allegra, S; Barros, M

    2015-02-01

    The effect of a high (chocolate) versus low fat/sugar (chow) food on a conditioned-place-preference (CPP) task was evaluated in marmoset monkeys. Anxiety-related behaviors and cortisol levels before and after the CPP task were also measured. Subjects were habituated to a two-compartment CPP box and then, on alternate days, had access to only one compartment during daily 15-min conditionings, for a total of 14 trials. Marmosets were provisioned with chocolate chips in the CC-paired compartment on odd-numbered trials and standard chow in the CW-paired compartment on even-numbered trials. They were then tested for preferring the CC-paired context after a 24-h interval. During the conditioning, a significantly greater amount (in kcal/trial) of chocolate was consumed than chow, yet the foraging pattern of both food types was similar. On the test trial, the time spent in the CC-paired context increased significantly compared to pre-CPP levels, yet this response was not readily predicted by baseline behavioral or cortisol levels. Also, the chocolate CPP response was positively correlated with foraging time, rather than the amount of calories consumed. The sudden absence of the food increased exploration, while the chocolate CPP effect was associated with vigilance - both anxiety-related behaviors in marmosets. This behavioral profile occurred regardless of any concomitant change or correlation with cortisol. Therefore, the high fat/sugar food was more prone to be overly consumed by the marmosets, to induce a CPP response and to lead to anxiety-related behavior in its absence. Copyright © 2014. Published by Elsevier Inc.

  9. Conditional recall and the frequency effect in the serial recall task: an examination of item-to-item associativity.

    Science.gov (United States)

    Miller, Leonie M; Roodenrys, Steven

    2012-11-01

    The frequency effect in short-term serial recall is influenced by the composition of lists. In pure lists, a robust advantage in the recall of high-frequency (HF) words is observed, yet in alternating mixed lists, HF and low-frequency (LF) words are recalled equally well. It has been argued that the preexisting associations between all list items determine a single, global level of supportive activation that assists item recall. Preexisting associations between items are assumed to be a function of language co-occurrence; HF-HF associations are high, LF-LF associations are low, and mixed associations are intermediate in activation strength. This account, however, is based on results when alternating lists with equal numbers of HF and LF words were used. It is possible that directional association between adjacent list items is responsible for the recall patterns reported. In the present experiment, the recall of three forms of mixed lists-those with equal numbers of HF and LF items and pure lists-was examined to test the extent to which item-to-item associations are present in serial recall. Furthermore, conditional probabilities were used to examine more closely the evidence for a contribution, since correct-in-position scoring may mask recall that is dependent on the recall of prior items. The results suggest that an item-to-item effect is clearly present for early but not late list items, and they implicate an additional factor, perhaps the availability of resources at output, in the recall of late list items.

  10. Neuroscience and Learning: Lessons from Studying the Involvement of a Region of Cerebellar Cortex in Eyeblink Classical Conditioning

    Science.gov (United States)

    Villarreal, Ronald P.; Steinmetz, Joseph E.

    2005-01-01

    How the nervous system encodes learning and memory processes has interested researchers for 100 years. Over this span of time, a number of basic neuroscience methods has been developed to explore the relationship between learning and the brain, including brain lesion, stimulation, pharmacology, anatomy, imaging, and recording techniques. In this…

  11. Goal orientation, perceived task outcome and task demands in mathematics tasks: effects on students' attitude in actual task settings.

    Science.gov (United States)

    Seegers, Gerard; van Putten, Cornelis M; de Brabander, Cornelis J

    2002-09-01

    In earlier studies, it has been found that students' domain-specific cognitions and personal learning goals (goal orientation) influence task-specific appraisals of actual learning tasks. The relations between domain-specific and task-specific variables have been specified in the model of adaptive learning. In this study, additional influences, i.e., perceived task outcome on a former occasion and variations in task demands, were investigated. The purpose of this study was to identify personality and situational variables that mediate students' attitude when confronted with a mathematics task. Students worked on a mathematics task in two subsequent sessions. Effects of perceived task outcome at the first session on students' attitude at the second session were investigated. In addition, we investigated how differences in task demands influenced students' attitude. Variations in task demands were provoked by different conditions in task-instruction. In one condition, students were told that the result on the test would add to their mark on mathematics. This outcome orienting condition was contrasted with a task-orienting condition where students were told that the results on the test would not be used to give individual grades. Participants were sixth grade students (N = 345; aged 11-12 years) from 14 primary schools. Multivariate and univariate analyses of (co)variance were applied to the data. Independent variables were goal orientation, task demands, and perceived task outcome, with task-specific variables (estimated competence for the task, task attraction, task relevance, and willingness to invest effort) as the dependent variables. The results showed that previous perceived task outcome had a substantial impact on students' attitude. Additional but smaller effects were found for variation in task demands. Furthermore, effects of previous perceived task outcome and task demands were related to goal orientation. The resulting pattern confirmed that, in general

  12. Task-Based Learning: The Interaction between Tasks and Learners.

    Science.gov (United States)

    Murphy, Jacky

    2003-01-01

    Investigates the relationship between tasks and learners in task-based learning. Findings suggest that manipulation of task characteristics and conditions may not achieve the intended pedagogic outcomes, and that new ways are needed to focus learners' attention of form without sacrificing the meaning-driven principles of task-based learning.…

  13. conditions

    Directory of Open Access Journals (Sweden)

    M. Venkatesulu

    1996-01-01

    Full Text Available Solutions of initial value problems associated with a pair of ordinary differential systems (L1,L2 defined on two adjacent intervals I1 and I2 and satisfying certain interface-spatial conditions at the common end (interface point are studied.

  14. Embodying approach motivation: body posture influences startle eyeblink and event-related potential responses to appetitive stimuli.

    Science.gov (United States)

    Price, Tom F; Dieckman, Laurtiz W; Harmon-Jones, Eddie

    2012-07-01

    Past research suggested that the motivational significance of images influences reflexive and electrocortical responses to those images (Briggs and Martin, 2009; Gard et al., 2007; Schupp et al., 2004), with erotica often exerting the largest effects for appetitive pictures (Grillon and Baas, 2003; Weinberg and Hajcak, 2010). This research paradigm, however, compares responses to different types of images (e.g., erotica vs. exciting sports scenes). This past motivational interpretation, therefore, would be further supported by experiments wherein appetitive picture content is held constant and motivational states are manipulated with a different method. In the present experiment, we tested the hypothesis that changes in physical postures associated with approach motivation influences reflexive and electrocortical responses to appetitive stimuli. Past research has suggested that bodily manipulations (e.g., facial expressions) play a role in emotion- and motivation-related physiology (Ekman and Davidson, 1993; Levenson et al., 1990). Extending these results, leaning forward (associated with a heightened urge to approach stimuli) relative to reclining (associated with less of an urge to approach stimuli) caused participants to have smaller startle eyeblink responses during appetitive, but not neutral, picture viewing. Leaning relative to reclining also caused participants to have larger LPPs to appetitive but not neutral pictures, and influenced ERPs as early as 100ms into stimulus viewing. This evidence suggests that body postures associated with approach motivation causally influence basic reflexive and electrocortical reactions to appetitive emotive stimuli. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Using memory for prior aircraft events to detect conflicts under conditions of proactive air traffic control and with concurrent task requirements.

    Science.gov (United States)

    Bowden, Vanessa K; Loft, Shayne

    2016-06-01

    In 2 experiments we examined the impact of memory for prior events on conflict detection in simulated air traffic control under conditions where individuals proactively controlled aircraft and completed concurrent tasks. Individuals were faster to detect conflicts that had repeatedly been presented during training (positive transfer). Bayesian statistics indicated strong evidence for the null hypothesis that conflict detection was not impaired for events that resembled an aircraft pair that had repeatedly come close to conflicting during training. This is likely because aircraft altitude (the feature manipulated between training and test) was attended to by participants when proactively controlling aircraft. In contrast, a minor change to the relative position of a repeated nonconflicting aircraft pair moderately impaired conflict detection (negative transfer). There was strong evidence for the null hypothesis that positive transfer was not impacted by dividing participant attention, which suggests that part of the information retrieved regarding prior aircraft events was perceptual (the new aircraft pair "looked" like a conflict based on familiarity). These findings extend the effects previously reported by Loft, Humphreys, and Neal (2004), answering the recent strong and unanimous calls across the psychological science discipline to formally establish the robustness and generality of previously published effects. (PsycINFO Database Record

  16. Dissociable effects of AMPA-induced lesions of the vertical limb diagonal band of Broca on performance of the 5-choice serial reaction time task and on acquisition of a conditional visual discrimination.

    Science.gov (United States)

    Muir, J L; Bussey, T J; Everitt, B J; Robbins, T W

    1996-12-01

    The aim of the present study was to investigate the role of the cholinergic innervation of the cingulate cortex in visual attentional function and acquisition of a visual conditional discrimination task. Following AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) lesions of the vertical limb diagonal band of Broca (VDB) which provides the main cholinergic projection to cingulate cortex, animals were not significantly impaired on the 5-choice serial reaction time task. This task, which provides a continuous performance test of visual attention, has previously been shown to be sensitive to AMPA lesions of the nucleus basalis magnocellularis (nbM). In contrast to the results obtained for visual attentional function, lesions of the VDB did significantly affect the acquisition of a visual conditional discrimination. While showing a significant facilitation in the early learning stage of acquiring this task animals with lesions of the VDB were significantly impaired during the late stages of learning this task. This late learning deficit was not the result of the animals being unable to learn the task due to the presence of the lesion throughout task acquisition as the results of a second experiment revealed that when animals were pre-trained to 70% accuracy on the task and then lesioned, the impairment in late learning was still apparent. In light of the results presented in the accompanying paper (Bussey et al., Behav. Brain Res., 1996), these results suggest that the early learning effects may be due to cholinergic denervation of the anterior cingulate cortex while the late learning effects may be due to denervation of the posterior cingulate cortex. Taken together with previous work indicating a role for the nbM cholinergic system in visual attentional function, these results suggest a role for the cholinergic innervation of the cingulate cortex in conditional learning but not for continuous attentional performance.

  17. Destruction of central noradrenergic neurones with DSP4 impairs the acquisition of temporal discrimination but does not affect memory for duration in a delayed conditional discrimination task.

    Science.gov (United States)

    al-Zahrani, S S; al-Ruwaitea, A S; Ho, M Y; Bradshaw, C M; Szabadi, E

    1997-03-01

    This experiment examined the effect of destroying central noradrenergic neurones using the selective neurotoxin N-(2-chloroethyl)-n-ethyl-2-bromobenzylamine (DSP4) on the acquisition of a temporal discrimination and on memory for duration, using a delayed conditional discrimination task. In phase I, rats that had received systemic treatment with DSP4 and vehicle-treated control rats were trained in a series of discrete trials to press lever A following a 2-s presentation of a light stimulus, and lever B following an 8-s presentation of the same stimulus. Following stimulus offset, a response on a panel placed midway between the two levers was required to initiate lever presentation; a single response on either lever resulted in withdrawal of both levers and, in the case of a "correct" response, reinforcer delivery. Both groups acquired accurate discrimination, achieving 90% correct choices within 50 sessions; the DSP4-treated group acquired accurate performance more slowly than the control group. In phase II, delays were interposed between stimulus offset and lever presentation in 50% of the trials. In the absence of a delay, discriminative accuracy was lower in the DSP4-treated group than in the control group. Accuracy declined as a function of post-stimulus delay in both groups; both groups showed a delay-dependent bias towards responding on lever A ("choose-short" bias). Neither of these effects differed significantly between the two groups. The concentrations of noradrenaline in the parietal cortex and hippocampus were reduced by 90% and 89% in the DSP4-treated group, compared to the levels in the control group, but the levels of dopamine, 5-hydroxytryptamine and 5-hydroxyindoleacetic acid did not differ significantly between the groups. The results confirm the deleterious effect of DSP4 on the acquisition of temporal discrimination, but do not provide evidence for a role of the noradrenergic innervation of the hippocampus and neocortex in temporal working

  18. Classical conditioned responses to absent tones

    Directory of Open Access Journals (Sweden)

    Häusler Udo

    2006-08-01

    Full Text Available Abstract Background Recent evidence for a tight coupling of sensorimotor processes in trained musicians led to the question of whether this coupling extends to preattentively mediated reflexes; particularly, whether a classically conditioned response in one of the domains (auditory is generalized to another (tactile/motor on the basis of a prior association in a second-order Pavlovian paradigm. An eyeblink conditioning procedure was performed in 17 pianists, serving as a model for overlearned audiomotor integration, and 14 non-musicians. Results: During the training session, subjects were conditioned to respond to auditory stimuli (piano tones. During a subsequent testing session, when subjects performed keystrokes on a silent piano, pianists showed significantly higher blink rates than non-musicians. Conclusion These findings suggest a tight coupling of the auditory and motor domains in musicians, pointing towards training-dependent mechanisms of strong cross-modal sensorimotor associations even on sub-cognitive processing levels.

  19. No transfer between conditions in balance training regimes relying on tasks with different postural demands: Specificity effects of two different serious games.

    Science.gov (United States)

    Naumann, Tim; Kindermann, Stefan; Joch, Michael; Munzert, Jörn; Reiser, Mathias

    2015-03-01

    Despite the increasing use of video games involving whole body movements to enhance postural control in health prevention and rehabilitation, there is no consistent proof that training effects actually transfer to other balance tasks. The present study aimed to determine whether training effects on two different video-game-based training devices were task-specific or could be transferred to either postural control in quiet stance or to performance on the other device. 37 young healthy adults were split into three groups: two intervention groups that trained for 30min on either the Nintendo(®) Wii Fit Balance Board or the MFT Challenge Disc(®) three times per week for 4 weeks and a control group that received no training. All games require participants to control virtual avatars by shifting the center of mass in different directions. Both devices differ in their physical properties. The Balance Board provides a stable surface, whereas the Challenge Disc can be tilted in all directions. Dependent variables were the game scores on both devices and the center of pressure (COP) displacements measured via force plate. At posttest, both intervention groups showed significant increases in performance on the trained games compared to controls. However, there were no relevant transfer effects to performance on the untrained device and no changes in COP path length in quiet stance. These results suggest that training effects on both devices are highly specific and do not transfer to tasks with different postural demands.

  20. Pre-task music improves swimming performance.

    Science.gov (United States)

    Smirmaul, B P; Dos Santos, R V; Da Silva Neto, L V

    2015-12-01

    The purpose of this study was to investigate the effects of pre-task music on swimming performance and other psychological variables. A randomized counterbalanced within-subjects (experimental and control condition) design was employed. Eighteen regional level male swimmers performed two 200-m freestyle swimming time trials. Participants were exposed to either 5 minutes of self-selected music (pre-task music condition) or 5 minutes of silence (control condition) and, after 1 minute, performed the swimming task. Swimming time was significantly shorter (-1.44%) in the pre-task music condition. Listening to pre-task music increased motivation to perform the swimming task, while arousal remained unchanged. While fatigue increased after the swimming task in both conditions, vigor, ratings of perceived exertion and affective valence were unaltered. It is concluded, for the first time, that pre-task music improves swimming performance.

  1. A Comparison of the Visual Attention Patterns of People with Aphasia and Adults without Neurological Conditions for Camera-Engaged and Task-Engaged Visual Scenes

    Science.gov (United States)

    Thiessen, Amber; Beukelman, David; Hux, Karen; Longenecker, Maria

    2016-01-01

    Purpose: The purpose of the study was to compare the visual attention patterns of adults with aphasia and adults without neurological conditions when viewing visual scenes with 2 types of engagement. Method: Eye-tracking technology was used to measure the visual attention patterns of 10 adults with aphasia and 10 adults without neurological…

  2. Behaviorally inhibited individuals demonstrate significantly enhanced conditioned response acquisition under non-optimal learning conditions.

    Science.gov (United States)

    Holloway, J L; Allen, M T; Myers, C E; Servatius, R J

    2014-03-15

    Behavioral inhibition (BI) is an anxiety vulnerability factor associated with hypervigilance to novel stimuli, threat, and ambiguous cues. The progression from anxiety risk to a clinical disorder is unknown, although the acquisition of defensive learning and avoidance may be a critical feature. As the expression of avoidance is also central to anxiety development, the present study examined avoidance acquisition as a function of inhibited temperament using classical eyeblink conditioning. Individuals were classified as behaviorally inhibited (BI) or non-inhibited (NI) based on combined scores from the Adult and Retrospective Measures of Behavioural Inhibition (AMBI and RMBI, respectively). Acquisition was assessed using delay, omission, or yoked conditioning schedules of reinforcement. Omission training was identical to delay, except that the emission of an eyeblink conditioned response (CR) resulted in omission of the unconditioned airpuff stimulus (US) on that trial. Each subject in the yoked group was matched on total BI score to a subject in the omission group, and received the same schedule of CS and US delivery, resulting in a partial reinforcement training schedule. Delay conditioning elicited significantly more CRs compared to the omission and yoked contingencies, the latter two of which did not differ from each other. Thus, acquisition of an avoidance response was not apparent. BI individuals demonstrated enhanced acquisition overall, while partial reinforcement training significantly distinguished between BI and NI groups. Enhanced learning in BI may be a function of an increased defensive learning capacity, or sensitivity to uncertainty. Further work examining the influence of BI on learning acquisition is important for understanding individual differences in disorder etiology in anxiety vulnerable cohorts.

  3. Effects of a no-go Task 2 on Task 1 performance in dual - tasking: From benefits to costs.

    Science.gov (United States)

    Janczyk, Markus; Huestegge, Lynn

    2017-04-01

    When two tasks are combined in a dual-task experiment, characteristics of Task 2 can influence Task 1 performance, a phenomenon termed the backward crosstalk effect (BCE). Besides instances depending on the (spatial) compatibility of both responses, a particularly interesting example was introduced by Miller (2006): If Task 2 was a no-go task (i.e., one not requiring any action at all), responses were slowed in Task 1. Subsequent work, however, also reported the opposite result-that is, faster Task 1 responses in cases of no-go Task 2 trials. We report three experiments aiming to more precisely identify the conditions under which a no-go Task 2 facilitates or impedes Task 1 performance. The results suggest that an adverse no-go BCE is only observed when the Task 2 response(s) are sufficiently prepared in advance, yielding strong inhibitory control demands for Task 2 that eventually hamper Task 1 processing as well (i.e., inhibitory costs). If this is not the case, encountering a no-go Task 2 trial facilitates Task 1 performance, suggesting that the underlying task representation is reduced to a single - task. These results are discussed in the context of other recent work on BCEs and of recently suggested accounts of the no-go BCE.

  4. Evolution of Task Partitioning in Swarm Robotics

    OpenAIRE

    Ferrante, Eliseo,; Duenez-Guzman, E.; Turgut, A. E.; Wenseleers, Tom

    2013-01-01

    International audience; Task-partitioning refers to the process whereby a task is divided into two or more sub-tasks. Through task partitioning both efficiency and effectiveness can be improved provided the right environmental conditions. We synthesize self-organized task partitioning behaviors for a swarm of mobile robots using artificial evolution. Through validation experiments, we show that the synthesized behaviors exploits behavioral specialization despite being based on homogeneous ind...

  5. Hippocampal-dependent Pavlovian conditioning in adult rats exposed to binge-like doses of ethanol as neonates.

    Science.gov (United States)

    Lindquist, Derick H

    2013-04-01

    Binge-like postnatal ethanol exposure produces significant damage throughout the brain in rats, including the cerebellum and hippocampus. In the current study, cue- and context-mediated Pavlovian conditioning were assessed in adult rats exposed to moderately low (3E; 3g/kg/day) or high (5E; 5g/kg/day) doses of ethanol across postnatal days 4-9. Ethanol-exposed and control groups were presented with 8 sessions of trace eyeblink conditioning followed by another 8 sessions of delay eyeblink conditioning, with an altered context presented over the last two sessions. Both forms of conditioning rely on the brainstem and cerebellum, while the more difficult trace conditioning also requires the hippocampus. The hippocampus is also needed to gate or modulate expression of the eyeblink conditioned response (CR) based on contextual cues. Results indicate that the ethanol-exposed rats were not significantly impaired in trace EBC relative to control subjects. In terms of CR topography, peak amplitude was significantly reduced by both doses of alcohol, whereas onset latency but not peak latency was significantly lengthened in the 5E rats across the latter half of delay EBC in the original training context. Neither dosage resulted in significant impairment in the contextual gating of the behavioral response, as revealed by similar decreases in CR production across all four treatment groups following introduction of the novel context. Results suggest ethanol-induced brainstem-cerebellar damage can account for the present results, independent of the putative disruption in hippocampal development and function proposed to occur following postnatal ethanol exposure.

  6. The CANMAT task force recommendations for the management of patients with mood disorders and comorbid medical conditions: diagnostic, assessment, and treatment principles.

    Science.gov (United States)

    Ramasubbu, Rajamannar; Beaulieu, Serge; Taylor, Valerie H; Schaffer, Ayal; McIntyre, Roger S

    2012-02-01

    Medical comorbidity is commonly encountered in individuals with major depressive disorder (MDD) and bipolar disorder (BD). The presence of medical comorbidity has diagnostic, prognostic, treatment, and etiologic implications underscoring the importance of timely detection and treatment. A selective review of relevant articles and reviews published in English-language databases (1968 to April 2011) was conducted. Studies describing epidemiology, temporality of onset, treatment implications, and prognosis were selected for review. A growing body of evidence from epidemiologic, clinical, and biologic studies suggests that the relationship between medical illness and mood disorder is bidirectional in nature. It provides support for the multiplay of shared and specific etiologic factors interlinking these conditions. This article describes the complex interactions between medical illness and mood disorders and provides a meaningful approach to their comorbid clinical diagnosis and management.

  7. Task Prioritization in Dual-Tasking: Instructions versus Preferences

    Science.gov (United States)

    Jansen, Reinier J.; van Egmond, René; de Ridder, Huib

    2016-01-01

    The role of task prioritization in performance tradeoffs during multi-tasking has received widespread attention. However, little is known on whether people have preferences regarding tasks, and if so, whether these preferences conflict with priority instructions. Three experiments were conducted with a high-speed driving game and an auditory memory task. In Experiment 1, participants did not receive priority instructions. Participants performed different sequences of single-task and dual-task conditions. Task performance was evaluated according to participants’ retrospective accounts on preferences. These preferences were reformulated as priority instructions in Experiments 2 and 3. The results showed that people differ in their preferences regarding task prioritization in an experimental setting, which can be overruled by priority instructions, but only after increased dual-task exposure. Additional measures of mental effort showed that performance tradeoffs had an impact on mental effort. The interpretation of these findings was used to explore an extension of Threaded Cognition Theory with Hockey’s Compensatory Control Model. PMID:27391779

  8. A data-driven algorithm for offline pupil signal preprocessing and eyeblink detection in low-speed eye-tracking protocols.

    Science.gov (United States)

    Pedrotti, Marco; Lei, Shengguang; Dzaack, Jeronimo; Rötting, Matthias

    2011-06-01

    Event detection is the conversion of raw eye-tracking data into events--such as fixations, saccades, glissades, blinks, and so forth--that are relevant for researchers. In eye-tracking studies, event detection algorithms can have a serious impact on higher level analyses, although most studies do not accurately report their settings. We developed a data-driven eyeblink detection algorithm (Identification-Artifact Correction [I-AC]) for 50-Hz eye-tracking protocols. I-AC works by first correcting blink-related artifacts within pupil diameter values and then estimating blink onset and offset. Artifact correction is achieved with data-driven thresholds, and more reliable pupil data are output. Blink parameters are defined according to previous studies on blink-related visual suppression. Blink detection performance was tested with experimental data by visually checking the actual correspondence between I-AC output and participants' eye images, recorded by the eyetracker simultaneously with gaze data. Results showed a 97% correct detection percentage.

  9. Performing Task Integration

    DEFF Research Database (Denmark)

    Elkjaer, Bente; Nickelsen, Niels Christian Mossfeldt

    . Here cross-professional coordination of work was done by scheduled communication twice a day. When we proposed a way for further integration of tasks through an all-inclusive team organization, we were met with resistance. We use the study to discuss whether relational coordination theory is able to do......In the paper, we deal with how to organize work for cross-professional knowledge sharing. We do so inspired by relational coordination theory, which is affiliated with positive organizational scholarship. Relational coordination theory is constituted by a combination of relationships marked...... away with differences regarding task definitions and working conditions as well as professional knowledge hierarchies and responsibilities for parts and wholes....

  10. Limited impairments of associative learning in a mouse model of accelerated senescence.

    Science.gov (United States)

    Yang, Yi; Wu, Guang-yan; Li, Xuan; Huang, He; Hu, Bo; Yao, Juan; Wu, Bing; Sui, Jian-feng

    2013-11-15

    Research concerning impairment of associative learning during aging remains limited. The senescence-accelerated mice (SAM) prone/8 (P8) has been proposed as a useful model for the study of aging, and SAM resistant/1(SAMR1) is its control as a normal aging strain. Classical eyeblink conditioning has long been served as a model of associative learning. In order to explore the effects of aging on associative learning in SAM, the present study successively tested three paradigms of eyeblink conditioning in SAMP8 and SAMR1: classical single cue trace eyeblink conditioning (TEC), discriminative trace eyeblink conditioning and reversal learning of TEC. Behavioral performance indicated that SAMP8 could acquire limited single-cue trace eyeblink conditioning task and two-tone discrimination trace eyeblink conditioning with a relative lower acquisition rate compared to SAMR1. Both SAMP8 and SAMR1 failed to acquire reversal learning of discriminative TEC, and SAMP8' startle reflex to tone CS was lower than SAMR1. These results indicated that the impairments of aging on associative learning were incomplete in SAMP8.

  11. Thermal comfort zone study based on equivalent temperature under task air conditioning system%基于等效温度的工位空调环境下热舒适区研究

    Institute of Scientific and Technical Information of China (English)

    任雨婷; 端木琳; 金权

    2016-01-01

    针对工位送风空调形式营造的非均匀热环境,利用等效温度指标对人体的局部和整体热感觉进行了评价。在准办公室环境对受试者进行了人体热反应实验,得到了不同刺激工况下人体各部位的热感觉和等效温度值,对比分析后发现:刺激部位等效温度值与非刺激部位等效温度值出现明显的分离现象;刺激温度和风速是影响刺激部位等效温度值的重要因素。由热感觉投票值与等效温度值的散点图发现,二者有很好的线性关系,通过拟合得到了适用于工位送风非均匀环境的等效温度舒适区范围。%Evaluates the local and overall thermal sensation using equivalent temperature index in the non-uniform thermal environment of task air conditioning system.Conducts the human thermal test in a mockup office, and obtains the data of local sensation and equivalent temperatures under different stimulating conditions.The results show that there is an obvious separation phenomenon between the equivalent temperature of stimulating site and that of non stimulating sites.The air temperature and velocity are the important factors to affect the equivalent temperature of the stimulating site.From the scatter plot, finds a good linear relationship between human thermal sensation vote and equivalent temperature.Obtains the equivalent temperature comfort zone for the non-uniform thermal environment with task air conditioning through the fitting method.

  12. Visuospatial tasks affect locomotor control more than nonspatial tasks in older people.

    Directory of Open Access Journals (Sweden)

    Jasmine C Menant

    Full Text Available Previous research has shown that visuospatial processing requiring working memory is particularly important for balance control during standing and stepping, and that limited spatial encoding contributes to increased interference in postural control dual tasks. However, visuospatial involvement during locomotion has not been directly determined. This study examined the effects of a visuospatial cognitive task versus a nonspatial cognitive task on gait speed, smoothness and variability in older people, while controlling for task difficulty.Thirty-six people aged ≥75 years performed three walking trials along a 20 m walkway under the following conditions: (i an easy nonspatial task; (ii a difficult nonspatial task; (iii an easy visuospatial task; and (iv a difficult visuospatial task. Gait parameters were computed from a tri-axial accelerometer attached to the sacrum. The cognitive task response times and percentage of correct answers during walking and seated trials were also computed.No significant differences in either cognitive task type error rates or response times were evident in the seated conditions, indicating equivalent task difficulty. In the walking trials, participants responded faster to the visuospatial tasks than the nonspatial tasks but at the cost of making significantly more cognitive task errors. Participants also walked slower, took shorter steps, had greater step time variability and less smooth pelvis accelerations when concurrently performing the visuospatial tasks compared with the nonspatial tasks and when performing the difficult compared with the easy cognitive tasks.Compared with nonspatial cognitive tasks, visuospatial cognitive tasks led to a slower, more variable and less smooth gait pattern. These findings suggest that visuospatial processing might share common networks with locomotor control, further supporting the hypothesis that gait changes during dual task paradigms are not simply due to limited attentional

  13. On Examining Communicative Tasks in Second Language Acquistion

    OpenAIRE

    2008-01-01

    Studies of second language acquisition (SLA) suggest that communicative tasks can provide the conditions and processes that may facilitate second language learning.  Attempting to understand how communicative tasks may promote SLA, this article examines communicative tasks in second language learning by (1) defining and categorizing tasks, (2) providing theoretical rationale for tasks with respect to meaningful oral exchanges or interaction generated from tasks, and (3) discussing how the li...

  14. "Task" as Research Construct

    Science.gov (United States)

    Seedhouse, Paul

    2005-01-01

    The article examines "task" as research construct as predominantly conceived in terms of task-as-workplan in the task-based learning/second language acquisition literature. It is suggested that "task" has weak construct validity and ontology in an overwhelmingly quantitative paradigm because the construct has a "split personality."…

  15. Scientists and the Selection Task.

    Science.gov (United States)

    Griggs, Richard A.; Ransdell, Sarah E.

    1986-01-01

    Presents findings of a study of scientists on the Wason four-card selection task, finding little understanding of the effect of disconfirmatory data in assessing conditionals. Found performance influenced by problem content. Explains performance as memory-cueing plus reasoning-by-analogy. (JM)

  16. Recalling academic tasks

    Science.gov (United States)

    Draper, Franklin Gno

    This study was focused on what students remembered about five middle school science tasks when they were juniors and seniors in high school. Descriptions of the five tasks were reconstructed from available artifacts and teachers' records, notes and recollections. Three of the five tasks were "authentic" in the sense that students were asked to duplicate the decisions practitioners make in the adult world. The other two tasks were more typical school tasks involving note taking and preparation for a quiz. All five tasks, however, involved use of computers. Students were interviewed to examine what and how well they recalled the tasks and what forms or patterns of recall existed. Analysis of their responses indicated that different kinds of tasks produced different levels of recall. Authentically situated tasks were remembered much better than routine school tasks. Further, authentic tasks centered on design elements were recalled better than those for which design was not as pivotal. Patterns of recall indicated that participants most often recalled the decisions they made, the scenarios of the authentically situated tasks, the consequences of their tasks and the social contexts of the classroom. Task events, in other words, appeared to form a framework upon which students constructed stories of the tasks. The more salient the events, the richer the story, the deeper and more detailed the recall of the task. Thus, authentic tasks appeared to lend themselves to creating stories better than regular school tasks and therefore such tasks were recalled better. Implications of these patterns of recall are discussed with respect to issues of school learning and assessment.

  17. Task-irrelevant perceptual expertise.

    Science.gov (United States)

    Wong, Yetta K; Folstein, Jonathan R; Gauthier, Isabel

    2011-12-05

    Perceptual learning (PL) and perceptual expertise (PE) are two fields of visual training studies that investigate how practice improves visual performance. However, previous research suggests that PL can be acquired in a task-irrelevant manner while PE cannot and that PL is highly specific to the training objects and conditions while PE generalizes. These differences are difficult to interpret since PL and PE studies tend to differ on multiple dimensions. We designed a training study with novel objects to compare PL and PE while varying only the training task, such that the training objects, visual field, training duration, and type of learning assessment were kept constant. Manipulations of the training task sufficed to produce the standard effects obtained in PE and PL. In contrast to prior studies, we demonstrated that some degree of PE can be acquired in a task-irrelevant manner, similar to PL. Task-irrelevant PE resulted in similar shape matching ability compared to the directly trained PE. In addition, learning in both PE and PL generalizes to different untrained conditions, which does not support the idea that PE generalizes while PL is specific. Degrees of generalization can be explained by considering the psychological space of the stimuli used for training and the test of transfer.

  18. Kokkos? Task DAG Capabilities.

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Harold C.; Ibanez, Daniel Alejandro

    2017-09-01

    This report documents the ASC/ATDM Kokkos deliverable "Production Portable Dy- namic Task DAG Capability." This capability enables applications to create and execute a dynamic task DAG ; a collection of heterogeneous computational tasks with a directed acyclic graph (DAG) of "execute after" dependencies where tasks and their dependencies are dynamically created and destroyed as tasks execute. The Kokkos task scheduler executes the dynamic task DAG on the target execution resource; e.g. a multicore CPU, a manycore CPU such as Intel's Knights Landing (KNL), or an NVIDIA GPU. Several major technical challenges had to be addressed during development of Kokkos' Task DAG capability: (1) portability to a GPU with it's simplified hardware and micro- runtime, (2) thread-scalable memory allocation and deallocation from a bounded pool of memory, (3) thread-scalable scheduler for dynamic task DAG, (4) usability by applications.

  19. Intellectual productivity under task ambient lighting

    OpenAIRE

    2016-01-01

    A subjective experiment was conducted to evaluate intellectual productivity in three lighting conditions: (a) conventional ambient lighting, (b) task ambient lighting with normal colour temperature (5000 K), and (c) task ambient lighting with high colour temperature (6200 K). In the experiment, cognitive tasks were given to 24 participants. The concentration time ratio, which is a quantitative and objective evaluation index of the degree of concentration, was measured. The results showed that...

  20. Project Tasks in Robotics

    DEFF Research Database (Denmark)

    Sørensen, Torben; Hansen, Poul Erik

    1998-01-01

    Description of the compulsary project tasks to be carried out as a part of DTU course 72238 Robotics......Description of the compulsary project tasks to be carried out as a part of DTU course 72238 Robotics...

  1. Components of competitor priming in task switching.

    Science.gov (United States)

    Teskey, Morgan L; Masson, Michael E J

    2017-07-17

    Executing an action in response to a stimulus is thought to result in the creation of an event code that integrates stimulus and action features (Allport, 1987; Hommel in Visual Cognition 5: 183-216, 1998). When switching between tasks, competitor priming occurs if a distractor stimulus cues the retrieval of a previously established event code in which that distractor is bound to a competing task, creating a source of interference with the current task whereby the observer is encouraged to apply the competing task to the distractor. We propose a second aspect of competitor priming: the misapplication of the retrieved competing task to the target stimulus. We report two task-switching experiments in which tasks applied to picture-word compound stimuli were manipulated to create conditions in which this second aspect of competitor priming could be revealed and distinguished from other sources of task- and stimulus-based priming. A substantial increase in competitor priming was observed when subjects switched between tasks that required very different processing operations and the competing task was highly relevant to the target stimulus. These results are consistent with our claim that competitor priming can result from applying the competing task either to the distractor that cued it or to the target stimulus.

  2. Task Analysis - Its Relation to Content Analysis.

    Science.gov (United States)

    Gagne, Robert M.

    Task analysis is a procedure having the purpose of identifying different kinds of performances which are outcomes of learning, in order to make possible the specification of optimal instructional conditions for each kind of outcome. Task analysis may be related to content analysis in two different ways: (1) it may be used to identify the probably…

  3. Launching Complex Tasks

    Science.gov (United States)

    Jackson, Kara J.; Shahan, Emily C.; Gibbons, Lynsey K.; Cobb, Paul A.

    2012-01-01

    Mathematics lessons can take a variety of formats. In this article, the authors discuss lessons organized around complex mathematical tasks. These lessons usually unfold in three phases. First, the task is introduced to students. Second, students work on solving the task. Third, the teacher "orchestrates" a concluding whole-class discussion in…

  4. Task assignment and coaching

    NARCIS (Netherlands)

    Dominguez-Martinez, S.

    2009-01-01

    An important task of a manager is to motivate her subordinates. One way in which a manager can give incentives to junior employees is through the assignment of tasks. How a manager allocates tasks in an organization, provides information to the junior employees about his ability. Without coaching fr

  5. The functional neuroanatomy of multitasking: combining dual tasking with a short term memory task.

    Science.gov (United States)

    Deprez, Sabine; Vandenbulcke, Mathieu; Peeters, Ron; Emsell, Louise; Amant, Frederic; Sunaert, Stefan

    2013-09-01

    Insight into the neural architecture of multitasking is crucial when investigating the pathophysiology of multitasking deficits in clinical populations. Presently, little is known about how the brain combines dual-tasking with a concurrent short-term memory task, despite the relevance of this mental operation in daily life and the frequency of complaints related to this process, in disease. In this study we aimed to examine how the brain responds when a memory task is added to dual-tasking. Thirty-three right-handed healthy volunteers (20 females, mean age 39.9 ± 5.8) were examined with functional brain imaging (fMRI). The paradigm consisted of two cross-modal single tasks (a visual and auditory temporal same-different task with short delay), a dual-task combining both single tasks simultaneously and a multi-task condition, combining the dual-task with an additional short-term memory task (temporal same-different visual task with long delay). Dual-tasking compared to both individual visual and auditory single tasks activated a predominantly right-sided fronto-parietal network and the cerebellum. When adding the additional short-term memory task, a larger and more bilateral frontoparietal network was recruited. We found enhanced activity during multitasking in components of the network that were already involved in dual-tasking, suggesting increased working memory demands, as well as recruitment of multitask-specific components including areas that are likely to be involved in online holding of visual stimuli in short-term memory such as occipito-temporal cortex. These results confirm concurrent neural processing of a visual short-term memory task during dual-tasking and provide evidence for an effective fMRI multitasking paradigm. © 2013 Elsevier Ltd. All rights reserved.

  6. Testing the Automatization Deficit Hypothesis of Dyslexia via a Dual-Task Paradigm.

    Science.gov (United States)

    Yap, Regina L.; van der Leij, Aryan

    1994-01-01

    Fourteen Dutch children with dyslexia were compared with controls on automatic processing under a dual task (motor balance task and auditory choice task) model. Results indicated the dyslexic group was more impaired in the dual task condition than in the single task condition, compared with controls. Findings support the automatization deficit…

  7. Efeitos de conjuntos de dicas em tarefas de discriminação condicional Efectos de conjuntos de prompts en tareas de discriminación condicional Effects of prompts sets in conditional discriminations tasks

    Directory of Open Access Journals (Sweden)

    Thalita Filier Cazetto

    2011-06-01

    pares de las relaciones condicionales. Los resultados mostraron que los prompts acerca de los pares de las relaciones condicionales genero un mejor rendimiento.Conditional discriminations allow that by teaching some behaviors, others will emerge without having to be directly taught. Despite the supposed teaching economy, difficulties have been reported in the establishment of the adequate stimulus control in such discriminations. The use of prompts, such as demonstrations and/or instructions, can help establishing the adequate stimulus control. The purpose of the present study was to evaluate whether there would be differences in performance when two sets of prompts were presented. The study included 20 children aged between 9 and 12 years divided into two groups. To the first group, a matching to sample task was presented added to prompts (demonstration and instruction about the correct comparison stimulus. To the second group the same procedure was presented, but the prompts were about the conditional relation pairs. The results showed that the prompts about the conditional relation pairs yielded better performances.

  8. Is performance in task-cuing experiments mediated by task set selection or associative compound retrieval?

    Science.gov (United States)

    Forrest, Charlotte L D; Monsell, Stephen; McLaren, Ian P L

    2014-07-01

    Task-cuing experiments are usually intended to explore control of task set. But when small stimulus sets are used, they plausibly afford learning of the response associated with a combination of cue and stimulus, without reference to tasks. In 3 experiments we presented the typical trials of a task-cuing experiment: a cue (colored shape) followed, after a short or long interval, by a digit to which 1 of 2 responses was required. In a tasks condition, participants were (as usual) directed to interpret the cue as an instruction to perform either an odd/even or a high/low classification task. In a cue + stimulus → response (CSR) condition, to induce learning of mappings between cue-stimulus compound and response, participants were, in Experiment 1, given standard task instructions and additionally encouraged to learn the CSR mappings; in Experiment 2, informed of all the CSR mappings and asked to learn them, without standard task instructions; in Experiment 3, required to learn the mappings by trial and error. The effects of a task switch, response congruence, preparation, and transfer to a new set of stimuli differed substantially between the conditions in ways indicative of classification according to task rules in the tasks condition, and retrieval of responses specific to stimulus-cue combinations in the CSR conditions. Qualitative features of the latter could be captured by an associative learning network. Hence associatively based compound retrieval can serve as the basis for performance with a small stimulus set. But when organization by tasks is apparent, control via task set selection is the natural and efficient strategy.

  9. Expression of the immediate-early gene-encoded protein Egr-1 (zif268) during in vitro classical conditioning.

    Science.gov (United States)

    Mokin, Maxim; Keifer, Joyce

    2005-01-01

    Expression of the immediate-early genes (IEGs) has been shown to be induced by activity-dependent synaptic plasticity or behavioral training and is thought to play an important role in long-term memory. In the present study, we examined the induction and expression of the IEG-encoded protein Egr-1 during an in vitro neural correlate of eyeblink classical conditioning. The results showed that Egr-1 protein expression as determined by immunocytochemistry and Western blot analysis rapidly increased during the early stages of conditioning and remained elevated during the later stages. Further, expression of Egr-1 protein required NMDA receptor activation as it was blocked by bath application of AP-5. These findings suggest that the IEG-encoded proteins such as Egr-1 are activated during relatively simple forms of learning in vertebrates. In this case, Egr-1 may have a functional role in the acquisition phase of conditioning as well as in maintaining expression of conditioned responses.

  10. Task-free MRI predicts individual differences in brain activity during task performance.

    Science.gov (United States)

    Tavor, I; Parker Jones, O; Mars, R B; Smith, S M; Behrens, T E; Jbabdi, S

    2016-04-01

    When asked to perform the same task, different individuals exhibit markedly different patterns of brain activity. This variability is often attributed to volatile factors, such as task strategy or compliance. We propose that individual differences in brain responses are, to a large degree, inherent to the brain and can be predicted from task-independent measurements collected at rest. Using a large set of task conditions, spanning several behavioral domains, we train a simple model that relates task-independent measurements to task activity and evaluate the model by predicting task activation maps for unseen subjects using magnetic resonance imaging. Our model can accurately predict individual differences in brain activity and highlights a coupling between brain connectivity and function that can be captured at the level of individual subjects.

  11. What Task Designers Do.

    Science.gov (United States)

    Johnson, Keith

    2000-01-01

    Describes a research project that is concerned with the design procedures followed by those engaged in designing pedagogic tasks for use in classrooms. Focuses on the part of the project that involves actual observation of designers in the process of developing one specific task for class use. Findings are presented under three headers: control…

  12. Supporting complex search tasks

    DEFF Research Database (Denmark)

    Gäde, Maria; Hall, Mark; Huurdeman, Hugo

    2015-01-01

    There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks, is fragme......There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks......, and recommendations, and supporting exploratory search to sensemaking and analytics, UI and UX design pose an overconstrained challenge. How do we know that our approach is any good? Supporting complex search task requires new collaborations across the whole field of IR, and the proposed workshop will bring together...

  13. Supporting complex search tasks

    DEFF Research Database (Denmark)

    Gäde, Maria; Hall, Mark; Huurdeman, Hugo;

    2015-01-01

    There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks......, is fragmented at best. The workshop addressed the many open research questions: What are the obvious use cases and applications of complex search? What are essential features of work tasks and search tasks to take into account? And how do these evolve over time? With a multitude of information, varying from...... introductory to specialized, and from authoritative to speculative or opinionated, when to show what sources of information? How does the information seeking process evolve and what are relevant differences between different stages? With complex task and search process management, blending searching, browsing...

  14. Single-Task and Dual-Task Gait Among Collegiate Athletes of Different Sport Classifications: Implications for Concussion Management.

    Science.gov (United States)

    Howell, David R; Oldham, Jessie R; DiFabio, Melissa; Vallabhajosula, Srikant; Hall, Eric E; Ketcham, Caroline J; Meehan, William P; Buckley, Thomas A

    2017-02-01

    Gait impairments have been documented following sport-related concussion. Whether preexisting gait pattern differences exist among athletes who participate in different sport classifications, however, remains unclear. Dual-task gait examinations probe the simultaneous performance of everyday tasks (ie, walking and thinking), and can quantify gait performance using inertial sensors. The purpose of this study was to compare the single-task and dual-task gait performance of collision/contact and noncontact athletes. A group of collegiate athletes (n = 265) were tested before their season at 3 institutions (mean age= 19.1 ± 1.1 years). All participants stood still (single-task standing) and walked while simultaneously completing a cognitive test (dual-task gait), and completed walking trials without the cognitive test (single-task gait). Spatial-temporal gait parameters were compared between collision/contact and noncontact athletes using MANCOVAs; cognitive task performance was compared using ANCOVAs. No significant single-task or dual-task gait differences were found between collision/contact and noncontact athletes. Noncontact athletes demonstrated higher cognitive task accuracy during single-task standing (P = .001) and dual-task gait conditions (P = .02) than collision/contact athletes. These data demonstrate the utility of a dual-task gait assessment outside of a laboratory and suggest that preinjury cognitive task performance during dual-tasks may differ between athletes of different sport classifications.

  15. Task-baseret kommunikativ sprogundervisning

    DEFF Research Database (Denmark)

    Pedersen, Michael Svendsen

    2015-01-01

    Definition af task-baseret sprogundervisning, kriterier for task. Forskning i Second Language Acquisition med brug af task, tilrettelæggelse af task-baseret kommunikativ undervisning. Begrænsninger i og perspektiver for videreudvikling af task-baseret sprogundervising-......Definition af task-baseret sprogundervisning, kriterier for task. Forskning i Second Language Acquisition med brug af task, tilrettelæggelse af task-baseret kommunikativ undervisning. Begrænsninger i og perspektiver for videreudvikling af task-baseret sprogundervising-...

  16. Task-specific dystonia: pathophysiology and management.

    Science.gov (United States)

    Sadnicka, Anna; Kassavetis, Panagiotis; Pareés, Isabel; Meppelink, Anne Marthe; Butler, Katherine; Edwards, Mark

    2016-09-01

    Task-specific dystonia is a form of isolated focal dystonia with the peculiarity of being displayed only during performance of a specific skilled motor task. This distinctive feature makes task-specific dystonia a particularly mysterious and fascinating neurological condition. In this review, we cover phenomenology and its increasingly broad-spectrum risk factors for the disease, critically review pathophysiological theories and evaluate current therapeutic options. We conclude by highlighting the unique features of task-specific dystonia within the wider concept of dystonia. We emphasise the central contribution of environmental risk factors, and propose a model by which these triggers may impact on the motor control of skilled movement. By viewing task-specific dystonia through this new lens which considers the disorder a modifiable disorder of motor control, we are optimistic that research will yield novel therapeutic avenues for this highly motivated group of patients.

  17. Energy Efficient Task Light

    DEFF Research Database (Denmark)

    Logadottir, Asta; Ardkapan, Siamak Rahimi; Johnsen, Kjeld

    2014-01-01

    The objectives of this work is to develop a task light for office lighting that fulfils the minimum requirements of the European standard EN12464 - 1 : Light and lighting – Lighting of work places, Part 1: Indoor workplaces and the Danish standard DS 700 : Lys og belysning I arbejdsrum , or more...... specifically the requirements that apply to the work area and the immediate surrounding area. By providing a task light that fulfils the requirements for task lighting and the immediate surrounding area, the general lighting only needs to provide the illuminance levels required for background lighting...... and thereby a reduction in installed power for general lighting of about 40 % compared to the way illuminance levels are designed in an office environment in Denmark today. This lighting strategy is useful when the placement of the task area is not defined in the space before the lighting is design ed...

  18. Organizing Core Tasks

    DEFF Research Database (Denmark)

    Boll, Karen

    Civil servants conduct the work which makes welfare states functions on an everyday bases: Police men police, school teachers teach, and tax inspectors inspect. Focus in this paper is on the core tasks of tax inspectors. The paper argues that their core task of securing the collection of revenue...... has remained much the same within the last 10 years. However, how the core task has been organized has changed considerable under the influence of various “organizing devices”. The paper focusses on how organizing devices such as risk assessment, output-focus, effect orientation, and treatment...... projects influence the organization of core tasks within the tax administration. The paper shows that the organizational transformations based on the use of these devices have had consequences both for the overall collection of revenue and for the employees’ feeling of “making a difference”. All in all...

  19. Anterior medial prefrontal cortex exhibits activation during task preparation but deactivation during task execution.

    Directory of Open Access Journals (Sweden)

    Hideya Koshino

    Full Text Available BACKGROUND: The anterior prefrontal cortex (PFC exhibits activation during some cognitive tasks, including episodic memory, reasoning, attention, multitasking, task sets, decision making, mentalizing, and processing of self-referenced information. However, the medial part of anterior PFC is part of the default mode network (DMN, which shows deactivation during various goal-directed cognitive tasks compared to a resting baseline. One possible factor for this pattern is that activity in the anterior medial PFC (MPFC is affected by dynamic allocation of attentional resources depending on task demands. We investigated this possibility using an event related fMRI with a face working memory task. METHODOLOGY/PRINCIPAL FINDINGS: Sixteen students participated in a single fMRI session. They were asked to form a task set to remember the faces (Face memory condition or to ignore them (No face memory condition, then they were given 6 seconds of preparation period before the onset of the face stimuli. During this 6-second period, four single digits were presented one at a time at the center of the display, and participants were asked to add them and to remember the final answer. When participants formed a task set to remember faces, the anterior MPFC exhibited activation during a task preparation period but deactivation during a task execution period within a single trial. CONCLUSIONS/SIGNIFICANCE: The results suggest that the anterior MPFC plays a role in task set formation but is not involved in execution of the face working memory task. Therefore, when attentional resources are allocated to other brain regions during task execution, the anterior MPFC shows deactivation. The results suggest that activation and deactivation in the anterior MPFC are affected by dynamic allocation of processing resources across different phases of processing.

  20. Dual task performance in normal aging: a comparison of choice reaction time tasks.

    Directory of Open Access Journals (Sweden)

    Eleftheria Vaportzis

    Full Text Available This study examined dual task performance in 28 younger (18-30 years and 28 older (>60 years adults using two sets of choice reaction time (RT tasks paired with digit tasks. Set one paired simple choice RT with digit forward; set two paired complex choice RT with digit backward. Each task within each set had easy and hard conditions. For the simple choice RT, participants viewed single letters and pressed a specified keyboard key if the letter was X or Z or a different key for other letters (easy. For the hard condition, there were 4 target letters (X, Z, O, Y. Digit forward consisted of 4 (easy or 5 (hard digits. For the complex choice RT, participants viewed 4×4 matrices of Xs and Os, and indicated whether four Xs (easy or four Xs or four Os (hard appeared in a row. Digit backward consisted of 3 (easy or 4 (hard digits. Within each set, participants performed every possible combination of tasks. We found that in the simple choice RT tasks older adults were significantly slower than, but as accurate as younger adults. In the complex choice RT tasks, older adults were significantly less accurate, but as fast as younger adults. For both age groups and both dual task sets, RT decreased and error rates increased with greater task difficulty. Older adults had greater dual task costs for error rates in the simple choice RT, whereas in the complex choice RT, it was the younger group that had greater dual task costs. Findings suggest that younger and older adults may adopt differential behavioral strategies depending on complexity and difficulty of dual tasks.

  1. Hysteresis in Mental Workload and Task Performance: The Influence of Demand Transitions and Task Prioritization.

    Science.gov (United States)

    Jansen, Reinier J; Sawyer, Ben D; van Egmond, René; de Ridder, Huib; Hancock, Peter A

    2016-12-01

    We examine how transitions in task demand are manifested in mental workload and performance in a dual-task setting. Hysteresis has been defined as the ongoing influence of demand levels prior to a demand transition. Authors of previous studies predominantly examined hysteretic effects in terms of performance. However, little is known about the temporal development of hysteresis in mental workload. A simulated driving task was combined with an auditory memory task. Participants were instructed to prioritize driving or to prioritize both tasks equally. Three experimental conditions with low, high, and low task demands were constructed by manipulating the frequency of lane changing. Multiple measures of subjective mental workload were taken during experimental conditions. Contrary to our prediction, no hysteretic effects were found after the high- to low-demand transition. However, a hysteretic effect in mental workload was found within the high-demand condition, which degraded toward the end of the high condition. Priority instructions were not reflected in performance. Online assessment of both performance and mental workload demonstrates the transient nature of hysteretic effects. An explanation for the observed hysteretic effect in mental workload is offered in terms of effort regulation. An informed arrival at the scene is important in safety operations, but peaks in mental workload should be avoided to prevent buildup of fatigue. Therefore, communication technologies should incorporate the historical profile of task demand. © 2016, Human Factors and Ergonomics Society.

  2. Task Switching in a Hierarchical Task Structure: Evidence for the Fragility of the Task Repetition Benefit

    Science.gov (United States)

    Lien, Mei-Ching; Ruthruff, Eric

    2004-01-01

    This study examined how task switching is affected by hierarchical task organization. Traditional task-switching studies, which use a constant temporal and spatial distance between each task element (defined as a stimulus requiring a response), promote a flat task structure. Using this approach, Experiment 1 revealed a large switch cost of 238 ms.…

  3. Effects of hypothesis and assigned task on question selection strategies.

    NARCIS (Netherlands)

    Meertens, R.W.; Koomen, W.; Delpeut, A.P.; Hager, G.A.

    1980-01-01

    70 undergraduates participated in an experiment in which they were provided with an extrovert profile (1-sided task condition) or an extrovert profile together with an introvert profile (2-sided task condition). Ss received information about a male target person, who was described either as an intro

  4. Board Task Performance

    DEFF Research Database (Denmark)

    Minichilli, Alessandro; Zattoni, Alessandro; Nielsen, Sabina

    2012-01-01

    This paper addresses recent calls to narrow the micro–macro gap in management research (Bamberger, 2008), by incorporating a macro-level context variable (country) in exploring micro-level determinants of board effectiveness. Following the integrated model proposed by Forbes and Milliken (1999), we...... identify three board processes as micro-level determinants of board effectiveness. Specifically, we focus on effort norms, cognitive conflicts and the use of knowledge and skills as determinants of board control and advisory task performance. Further, we consider how two different institutional settings...... influence board tasks, and how the context moderates the relationship between processes and tasks. Our hypotheses are tested on a survey-based dataset of 535 medium-sized and large industrial firms in Italy and Norway, which are considered to substantially differ along legal and cultural dimensions...

  5. Survival Processing and the Stroop Task

    Directory of Open Access Journals (Sweden)

    Stephanie A. Kazanas

    2015-11-01

    Full Text Available This study was designed to investigate the impact of survival processing with a novel task for this paradigm: the Stroop color-naming task. As the literature is mixed with regard to task generalizability, with survival processing promoting better memory for words, but not better memory for faces or paired associates, these types of task investigations are important to a growing field of research. Using the Stroop task provides a unique contribution, as identifying items by color is an important evolutionary adaptation and not specific to humans as is the case with word recall. Our results indicate that survival processing, with its accompanying survival-relevance rating task, remains the best mnemonic strategy for word memory. However, our results also indicate that presenting the survival passage does not motivate better color-naming performance than color-naming alone. In addition, survival processing led to a larger amount of Stroop interference, though not significantly larger than the other conditions. Together, these findings suggest that considering one’s survival when performing memory and attention-based tasks does not enhance cognitive performance generally, although greater allocation of attentional resources to color-incongruent concrete objects could be considered adaptive. These findings support the notion that engaging in deeper processing via survival-relevance ratings may preserve these words across a variety of experimental manipulations.

  6. Algebra task & drill sheets

    CERN Document Server

    Reed, Nat

    2011-01-01

    For grades 6-8, our State Standards-based combined resource meets the algebraic concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. The task sheets introduce the mathematical concepts to the students around a central problem taken from real-life experiences, while the drill sheets provide warm-up and timed practice questions for the students to strengthen their procedural proficiency skills. Included are opportunities for problem-solving, patterning, algebraic graphing, equations and determining averages. The combined task & drill sheets

  7. Algebra task & drill sheets

    CERN Document Server

    Reed, Nat

    2011-01-01

    For grades 3-5, our State Standards-based combined resource meets the algebraic concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. The task sheets introduce the mathematical concepts to the students around a central problem taken from real-life experiences, while the drill sheets provide warm-up and timed practice questions for the students to strengthen their procedural proficiency skills. Included are opportunities for problem-solving, patterning, algebraic graphing, equations and determining averages. The combined task & drill sheets

  8. Dynamic task-allocation for Unmanned Aircraft Systems

    Science.gov (United States)

    Bakker, Tim

    This dissertation addresses improvements to a consensus based task allocation algorithms for improving the Quality of Service in multi-task and multi-agent environments. Research in the past has led to many centralized task allocation algorithms where a central computation unit is calculating the global optimum task allocation solution. The centralized algorithms are plagued by creating a single point of failure and the bandwidth needed for creating consistent and accurate situational awareness off all agents. This work will extend upon a widely researched decentralized task assignment algorithm based on the consensus principle. Although many extensions have led to improvements of the original algorithm, there is still much opportunity for improvement in providing sufficient and reliable task assignments in real-world dynamic conditions and changing environments. This research addresses practical changes made to the consensus based task allocation algorithms for improving the Quality of Service in multi-task and multi-agent environments.

  9. A Daunting Task Still

    Institute of Scientific and Technical Information of China (English)

    ZHANG ZHIPING

    2010-01-01

    @@ Despite steady economic growth for three decades, China is still a developing country facing daunting poverty alleviation tasks. According to the poverty line of 1,196 yuan ($176) per capita net income in a year set in March 2009, the country still has a poverty population of more than 40 million, mainly living in rural areas.

  10. Task 1 quarternary tectonics

    Energy Technology Data Exchange (ETDEWEB)

    Bell, J.W.

    1994-12-31

    Activities on the task of quarternary tectonics for the Yucca Mountain Site investigations are described. Technical topics include: A preliminary reveiw of Bare Mountain Trench; A preliminary detailed lineament map of the Southwestern part of the proposed repository; A discussion on the 1994 Double Spring Flat, Nevada earthquake; and evidence for temporal clustering.

  11. Can tasks be inherently boring?

    Science.gov (United States)

    Charney, Evan

    2013-12-01

    Kurzban et al. argue that the experiences of "effort," "boredom," and "fatigue" are indications that the costs of a task outweigh its benefits. Reducing the costs of tasks to "opportunity costs" has the effect of rendering tasks costless and of denying that they can be inherently boring or tedious, something that "vigilance tasks" were intentionally designed to be.

  12. The carry-over effect of competition in task-sharing: evidence from the joint Simon task.

    Science.gov (United States)

    Iani, Cristina; Anelli, Filomena; Nicoletti, Roberto; Rubichi, Sandro

    2014-01-01

    The Simon effect, that is the advantage of the spatial correspondence between stimulus and response locations when stimulus location is a task-irrelevant dimension, occurs even when the task is performed together by two participants, each performing a go/no-go task. Previous studies showed that this joint Simon effect, considered by some authors as a measure of self-other integration, does not emerge when during task performance co-actors are required to compete. The present study investigated whether and for how long competition experienced during joint performance of one task can affect performance in a following joint Simon task. In two experiments, we required pairs of participants to perform together a joint Simon task, before and after jointly performing together an unrelated non-spatial task (the Eriksen flanker task). In Experiment 1, participants always performed the joint Simon task under neutral instructions, before and after performing the joint flanker task in which they were explicitly required either to cooperate with (i.e., cooperative condition) or to compete against a co-actor (i.e., competitive condition). In Experiment 2, they were required to compete during the joint flanker task and to cooperate during the subsequent joint Simon task. Competition experienced in one task affected the way the subsequent joint task was performed, as revealed by the lack of the joint Simon effect, even though, during the Simon task participants were not required to compete (Experiment 1). However, prior competition no longer affected subsequent performance if a new goal that created positive interdependence between the two agents was introduced (Experiment 2). These results suggest that the emergence of the joint Simon effect is significantly influenced by how the goals of the co-acting individuals are related, with the effect of competition extending beyond the specific competitive setting and affecting subsequent interactions.

  13. Effect of fixation tasks on multifocal visual evoked potentials.

    Science.gov (United States)

    Martins, Alessandra; Klistorner, Alexander; Graham, Stuart; Billson, Frank

    2005-10-01

    This study investigated the effects of cognitive influence on the multifocal visual evoked potential (mVEP) at different levels of eccentricity. Three different foveal fixation conditions were utilized involving varying levels of task complexity. A more complex visual fixation task has been known to suppress peripheral signals in subjective testing. Twenty normal subjects had monocular mVEPs recorded using the AccuMap objective perimeter. This allowed simultaneous stimulation of 58 segments of the visual field to an eccentricity of 24 degrees. The mVEP was recorded using three different fixation conditions in random order. During task 1 the subject passively viewed the central fixation area. For task 2 alternating numbers were displayed within the fixation area; the subject on viewing the number '3' in the central fixation area indicated recognition by pressing a button. Throughout task 3, numbers were displayed as in task 2. The subject had the cognitive task of summating all the numbers. Analysis revealed that the increased attention and concentration demanded by tasks 2 and 3 in comparison with task 1 resulted in significantly enhanced central amplitudes of 9.41% (Mann-Whitney P = 0.0002) and 13.45% (P = 0.0002), respectively. These amplitudes became reduced in the periphery and approached those of task 1, resulting in no significant difference between the three tasks. Latencies demonstrated no significant difference between each task nor at any eccentricity (P > 0.05). As the complexity of each task increased the amount of alpha rhythm was significantly reduced. Our findings indicate that task 1 required a minimal demand of cognition and was associated with the greatest amount of alpha rhythm. It was also the most difficult to perform because of loss of interest. The other two tasks required a greater demand of higher order cognitive skills resulting in significantly enhanced amplitudes centrally and the attenuation of alpha rhythm. Therefore, amplitudes are

  14. Effect of Redundant Haptic Information on Task Performance during Visuo-Tactile Task Interruption and Recovery.

    Science.gov (United States)

    Moon, Hee-Seung; Baek, Jongsoo; Seo, Jiwon

    2016-01-01

    Previous studies have revealed that interruption induces disruptive influences on the performance of cognitive tasks. While much research has focused on the use of multimodal channels to reduce the cost of interruption, few studies have utilized haptic information as more than an associative cue. In the present study, we utilized a multimodal task interruption scenario involving the simultaneous presentation of visual information and haptic stimuli in order to investigate how the combined stimuli affect performance on the primary task (cost of interruption). Participants were asked to perform a two-back visuo-tactile task, in which visual and haptic stimuli were presented simultaneously, which was interrupted by a secondary task that also utilized visual and haptic stimuli. Four experimental conditions were evaluated: (1) paired information (visual stimulus + paired haptic stimulus) with interruption; (2) paired information without interruption; (3) non-paired information (visual stimulus + non-paired haptic stimulus) with interruption; and (4) non-paired information without interruption. Our findings indicate that, within a visuo-tactile task environment, redundant haptic information may not only increase accuracy on the primary task but also reduce the cost of interruption in terms of accuracy. These results suggest a new way of understanding the task recovery process within a multimodal environment.

  15. Effect of Redundant Haptic Information on Task Performance During Visuo-Tactile Task Interruption and Recovery

    Directory of Open Access Journals (Sweden)

    Hee-Seung Moon

    2016-12-01

    Full Text Available Previous studies have revealed that interruption induces disruptive influences on the performance of cognitive tasks. While much research has focused on the use of multimodal channels to reduce the cost of interruption, few studies have utilized haptic information as more than an associative cue. In the present study, we utilized a multimodal task interruption scenario involving the simultaneous presentation of visual information and haptic stimuli in order to investigate how the combined stimuli affect performance on the primary task (cost of interruption. Participants were asked to perform a two-back visuo-tactile task, in which visual and haptic stimuli were presented simultaneously, which was interrupted by a secondary task that also utilized visual and haptic stimuli. Four experimental conditions were evaluated: (1 paired information (visual stimulus + paired haptic stimulus with interruption; (2 paired information without interruption; (3 non-paired information (visual stimulus + non-paired haptic stimulus with interruption; and (4 non-paired information without interruption. Our findings indicate that, within a visuo-tactile task environment, redundant haptic information may not only increase accuracy on the primary task but also reduce the cost of interruption in terms of accuracy. These results suggest a new way of understanding the task recovery process within a multimodal environment.

  16. Task switching and response correspondence in the psychological refractory period paradigm

    Science.gov (United States)

    Lien, Mei-Ching; Schweickert, Richard; Proctor, Robert W.

    2003-01-01

    Three experiments examined the effects of task switching and response correspondence in a psychological refractory period paradigm. A letter task (vowel-consonant) and a digit task (odd-even) were combined to form 4 possible dual-task pairs in each trial: letter-letter, letter-digit, digit-digit, and digit-letter. Foreknowledge of task transition (repeat or switch) and task identity (letter or digit) was varied across experiments: no foreknowledge in Experiment 1, partial foreknowledge (task transition only) in Experiment 2, and full foreknowledge in Experiment 3. For all experiments, the switch cost for Task 2 was additive with stimulus onset asynchrony, and the response-correspondence effect for Task 2 was numerically smaller in the switch condition than in the repeat condition. These outcomes suggest that reconfiguration for Task 2 takes place after the central processing of Task 1 and that the crosstalk correspondence effect is due to response activation by way of stimulus-response associations.

  17. Horizontal plane head stabilization during locomotor tasks.

    Science.gov (United States)

    Cromwell, R L; Newton, R A; Carlton, L G

    2001-03-01

    Frequency characteristics of head stabilization were examined during locomotor tasks in healthy young adults(N = 8) who performed normal walking and 3 walking tasks designed to produce perturbations primarily in the horizontal plane. In the 3 walking tasks, the arms moved in phase with leg movement, with abnormally large amplitude, and at twice the frequency of leg movement. Head-in-space angular velocity was examined at the predominant frequencies of trunk motion. Head movements in space occurred at low frequencies ( 4.0 Hz) when the arms moved at twice the frequency of the legs. Head stabilization strategies were determined from head-on-trunk with respect to trunk frequency profiles derived from angular velocity data. During natural walking at low frequencies (head-on-trunk movement was less than trunk movement. At frequencies 3.0 Hz or greater, equal and opposite compensatory movement ensured head stability. When arm swing was altered, compensatory movement guaranteed head stability at all frequencies. Head stabilization was successful for frequencies up to 10.0 Hz during locomotor tasks. Maintaining head stability at high frequencies during voluntary tasks suggests that participants used feedforward mechanisms to coordinate head and trunk movements. Maintenance of head stability during dynamic tasks allows optimal conditions for vestibulo-ocular reflex function.

  18. Features or tasks?

    DEFF Research Database (Denmark)

    Heilesen, Simon

    In this paper for the Workshop on Human-computer interaction and e-learning, NordiCHI 2002, the author argues that in developing innovative E-learning systems, especially if constructivist pedagogy is to be applied, it will be useful to model the user interface on the often complex tasks...... that the user has to perform rather than just focusing on technical features (and adapting system use to them)....

  19. Gap Task Force

    CERN Multimedia

    Lissuaer, D

    One of the more congested areas in the ATLAS detector is the GAP region (the area between the Barrel Calorimeter and the End Cap calorimeter) where Inner Detector services, LAr Services and some Tile services all must co-habitat in a very limited area. It has been clear for some time that the space in the GAP region is not sufficient to accommodate all that is needed. In the last few month additional problems of routing all the services to Z=0 have been encountered due to the very limited space between the Tile Calorimeter and the first layer of Muon chambers. The Technical Management Board (TMB) and the Executive Board (EB) decided in the middle of March to establish a Task Force to look at this problem and come up with a solution within well-specified guidelines. The task force consisted of experts from the ID, Muon, Liquid Argon and Tile systems in addition to experts from the Technical Coordination team and the Physics coordinator. The task force held many meetings and in general there were some very l...

  20. Mobile Thread Task Manager

    Science.gov (United States)

    Clement, Bradley J.; Estlin, Tara A.; Bornstein, Benjamin J.

    2013-01-01

    The Mobile Thread Task Manager (MTTM) is being applied to parallelizing existing flight software to understand the benefits and to develop new techniques and architectural concepts for adapting software to multicore architectures. It allocates and load-balances tasks for a group of threads that migrate across processors to improve cache performance. In order to balance-load across threads, the MTTM augments a basic map-reduce strategy to draw jobs from a global queue. In a multicore processor, memory may be "homed" to the cache of a specific processor and must be accessed from that processor. The MTTB architecture wraps access to data with thread management to move threads to the home processor for that data so that the computation follows the data in an attempt to avoid L2 cache misses. Cache homing is also handled by a memory manager that translates identifiers to processor IDs where the data will be homed (according to rules defined by the user). The user can also specify the number of threads and processors separately, which is important for tuning performance for different patterns of computation and memory access. MTTM efficiently processes tasks in parallel on a multiprocessor computer. It also provides an interface to make it easier to adapt existing software to a multiprocessor environment.

  1. The minimum entropy principle and task performance.

    Science.gov (United States)

    Guastello, Stephen J; Gorin, Hillary; Huschen, Samuel; Peters, Natalie E; Fabisch, Megan; Poston, Kirsten; Weinberger, Kelsey

    2013-07-01

    According to the minimum entropy principle, efficient cognitive performance is produced with a neurocognitive strategy that involves a minimum of degrees of freedom. Although high performance is often regarded as consistent performance as well, some variability in performance still remains which allows the person to adapt to changing goal conditions or fatigue. The present study investigated the connection between performance, entropy in performance, and four task-switching strategies. Fifty-one undergraduates performed 7 different computer-based cognitive tasks producing sets of 49 responses under instructional conditions requiring task quotas or no quotas. The temporal patterns of performance were analyzed using orbital decomposition to extract pattern types and lengths, which were then compared with regard to Shannon entropy, topological entropy, and overall performance. Task switching strategies from a previous study were available for the same participants as well. Results indicated that both topological entropy and Shannon entropy were negatively correlated with performance. Some task-switching strategies produced lower entropy in performance than others. Stepwise regression showed that the top three predictors of performance were Shannon entropy and arithmetic and spatial abilities. Additional implications for the prediction of work performance with cognitive ability measurements and the applicability of the minimum entropy principle to multidimensional performance criteria and team work are discussed.

  2. Modality and Task Switching Interactions using Bi-Modal and Bivalent Stimuli

    Science.gov (United States)

    Sandhu, Rajwant; Dyson, Benjamin J.

    2013-01-01

    Investigations of concurrent task and modality switching effects have to date been studied under conditions of uni-modal stimulus presentation. As such, it is difficult to directly compare resultant task and modality switching effects, as the stimuli afford both tasks on each trial, but only one modality. The current study investigated task and…

  3. An Empirical Analysis of Interspersal Research Evidence, Implications, and Applications of the Discrete Task Completion Hypothesis.

    Science.gov (United States)

    Skinner, Christopher H.

    2002-01-01

    Researchers have posited that when students work on assignments with many discrete tasks, that each completed discrete task may be a conditioned reinforcer. If the discrete task completion hypothesis is accurate, then relative task completion rates should influence choice behavior in the same manner as relative rates of reinforcement. Results of a…

  4. Effects of Gait and Cognitive Task Difficulty on Cognitive-Motor Interference in Aging

    Directory of Open Access Journals (Sweden)

    Prudence Plummer-D'Amato

    2012-01-01

    Full Text Available Although gait-related dual-task interference in aging is well established, the effect of gait and cognitive task difficulty on dual-task interference is poorly understood. The purpose of this study was to examine the effect of gait and cognitive task difficulty on cognitive-motor interference in aging. Fifteen older adults (72.1 years, SD 5.2 and 20 young adults (21.7 years, SD 1.6 performed three walking tasks of varying difficulty (self-selected speed, fast speed, and fast speed with obstacle crossing under single- and dual-task conditions. The cognitive tasks were the auditory Stroop task and the clock task. There was a significant Group × Gait Task × Cognitive Task interaction for the dual-task effect on gait speed. After adjusting for education, there were no significant effects of gait or cognitive task difficulty on the dual-task effects on cognitive task performance. The results of this study provide evidence that gait task difficulty influences dual-task effects on gait speed, especially in older adults. Moreover, the effects of gait task difficulty on dual-task interference appear to be influenced by the difficulty of the cognitive task. Education is an important factor influencing cognitive-motor interference effects on cognition, but not gait.

  5. Impact of task design on task performance and injury risk: case study of a simulated drilling task.

    Science.gov (United States)

    Alabdulkarim, Saad; Nussbaum, Maury A; Rashedi, Ehsan; Kim, Sunwook; Agnew, Michael; Gardner, Richard

    2016-08-31

    Existing evidence is limited regarding the influence of task design on performance and ergonomic risk, or the association between these two outcomes. In a controlled experiment, we constructed a mock fuselage to simulate a drilling task common in aircraft manufacturing, and examined the effect of three levels of workstation adjustability on performance as measured by productivity (e.g. fuselage completion time) and quality (e.g. fuselage defective holes), and ergonomic risk as quantified using two common methods (rapid upper limb assessment and the strain index). The primary finding was that both productivity and quality significantly improved with increased adjustability, yet this occurred only when that adjustability succeeded in reducing ergonomic risk. Supporting the inverse association between ergonomic risk and performance, the condition with highest adjustability created the lowest ergonomic risk and the best performance while there was not a substantial difference in ergonomic risk between the other two conditions, in which performance was also comparable. Practitioner Summary: Findings of this study supported a causal relationship between task design and both ergonomic risk and performance, and that ergonomic risk and performance are inversely associated. While future work is needed under more realistic conditions and a broader population, these results may be useful for task (re)design and to help cost-justify some ergonomic interventions.

  6. [The effect of reading tasks on learning from multiple texts].

    Science.gov (United States)

    Kobayashi, Keiichi

    2014-06-01

    This study examined the effect of reading tasks on the integration of content and source information from multiple texts. Undergraduate students (N = 102) read five newspaper articles about a fictitious incident in either a summarization task condition or an evaluation task condition. Then, they performed an integration test and a source choice test, which assessed their understanding of a situation described in the texts and memory for the sources of text information. The results indicated that the summarization and evaluation task groups were not significantly different in situational understanding. However, the summarization task group significantly surpassed the evaluation task group for source memory. No significant correlation between the situational understanding and the source memory was found for the summarization group, whereas a significant positive correlation was found for the evaluation group. The results are discussed in terms of the documents model framework.

  7. Conditioned Inhibition in a Rodent Model of Attention-Deficit/Hyperactivity Disorder

    Science.gov (United States)

    Green, John T.; Chess, Amy C.; Conquest, Cynthia J.; Yegla, Brittney A.

    2011-01-01

    A deficit in inhibition may underlie some of the symptoms of Attention-deficit/hyperactivity disorder (ADHD), particularly impulsivity. However, the data on inhibitory deficits in children with ADHD are mixed. Moreover, there has been little characterization of inhibitory processes in animal models of ADHD. Pavlov’s conditioned inhibition procedure allows a direct assessment of the inhibitory status of a stimulus via summation and retardation tests. Therefore, in the current study we examined conditioned inhibition in spontaneously hypertensive rats (SHRs), the most well-validated animal model of ADHD. SHRs and Wistar rats were trained in a simultaneous feature-negative discrimination in eyeblink conditioning. Each session consisted of a mixture of two trial types: a tone paired with a periocular stimulation (A+) or a tone and light presented simultaneously without a periocular stimulation (XA−). Both SHRs and Wistars were able to discriminate A+ from XA− trials. In subsequent summation (X presented simultaneously with a different conditioned excitor, B) and retardation (X paired with the periocular stimulation) tests, the presence of inhibition to X was confirmed in both SHRs and Wistars: X reduced responding to B and X was slow to develop excitation when paired with periocular stimulation. These results are the first to demonstrate Pavlovian conditioned inhibition in SHRs and to use a summation and a retardation test to confirm X as a conditioned inhibitor. The data indicate that conditioned inhibition is intact in SHRs, thus inhibitory processes that do not require prefrontal cortex or cerebellum may be normal in this strain. PMID:22004263

  8. Ranking Performance Measures in Multi-Task Agencies

    DEFF Research Database (Denmark)

    Christensen, Peter Ove; Sabac, Florin; Tian, Joyce

    2010-01-01

    We derive sufficient conditions for ranking performance evaluation systems in multi-task agency models (using both optimal and linear contracts) in terms of a second-order stochastic dominance (SSD) condition on the likelihood ratios. The SSD condition can be replaced by a variance-covariance mat......We derive sufficient conditions for ranking performance evaluation systems in multi-task agency models (using both optimal and linear contracts) in terms of a second-order stochastic dominance (SSD) condition on the likelihood ratios. The SSD condition can be replaced by a variance...

  9. Task Dominance Determines Backward Inhibition in Task Switching

    Directory of Open Access Journals (Sweden)

    Kerstin Jost

    2017-05-01

    Full Text Available Switching between tasks is assumed to be accompanied by inhibiting currently irrelevant, but competing tasks. A dominant task that strongly interferes with performing a weaker task may receive especially strong inhibition. We tested this prediction by letting participants switch among three tasks that differ in dominance: a location discrimination task with strong stimulus–response bindings (responding with left-hand and right-hand button presses to stimuli presented left or right to the fixation cross was combined with a color/pattern and a shape discrimination task, for which stimulus–response mappings were arbitrary (e.g., left-hand button press mapped to a red stimulus. Across three experiments, the dominance of the location task was documented by faster and more accurate responses than in the other tasks. This even held for incompatible stimulus–response mappings (i.e., right-hand response to a left-presented stimulus and vice versa, indicating that set-level compatibility (i.e., “dimension overlap” was sufficient for making this location task dominant. As a behavioral marker for backward inhibition, we utilized n-2 repetition costs that are defined by higher reaction times for a switch back to a just abandoned and thus just inhibited task (ABA sequence than for a switch to a less recently inhibited task (CBA, n-2 non-repetition. Reliable n-2 task repetition costs were obtained for all three tasks. Importantly, these costs were largest for the location task, suggesting that inhibition indeed was stronger for the dominant task. This finding adds to other evidence that the amount of inhibition is adjusted in a context-sensitive way.

  10. Calorimetry Task Force Report

    CERN Document Server

    Abdullin, Salavat; Banerjee, Sunanda; Beauceron, Stephanie; Beaudette, Florian; Bhatti, Anwar; Chlebana, Frank; Cossutti, Fabio; Hirschauer, James; Ivanchenko, V; Jang, Dong Wook; Jun, Soon Yung; Kunori, Shuichi; Kroeger, Rob; Liu, Yanwen; Moeller, Anthony; Paulini, Manfred; Piperov, Stefan; Rahmat, Rahmat; Rovelli, Chiara; Safronov, Grigory; Sharma, Seema; Spiropulu, Maria; Yetkin, Taylan

    2010-01-01

    In this note we summarize the progress made by the calorimeter simulation task force (CaloTF) over the past year. The CaloTF was established in February 2008 in order to understand and reconcile the discrepancies observed between the CMS calorimetry simulation and test beam data recorded during 2004 and 2006. The simulation has been significantly improved by using a newer version of Geant4 and an improved physics list for the full CMS detector simulation. Simulation times have been reduced by introducing flexible parameterizations to describe showering in the calorimeter (using a Gflash-like approach) which have been tuned to the test beam data.

  11. Quarternary tectonics, Task 1

    Energy Technology Data Exchange (ETDEWEB)

    Bell, J.W.

    1993-09-30

    Activities conducted for the evaluation of the geology and seismotectonics stability of Yucca Mountain as a potential site for the underground disposal of high-level radioactive wastes continued. Tasks concerned with quaternary tectonics include: scheduling of photography of Little Skull Mountain area; the collection and dating of rock varnish samples from the 1932 Cedar Mountain earthquake area for carbon 14 AMS and cation-ratio analysis; collection of samples for thermoluminescence dating from the 1932 Cedar Mountain earthquake area; mapping of the northern area of Crater Flat; and surveying of the May 17, 1993 Eureka the Valley earthquake area.

  12. 一种张量扩展的条件随机场模型及其在自然语言处理任务中的应用%Novel conditional random field model extended by tensor and its application in natural language processing tasks

    Institute of Scientific and Technical Information of China (English)

    冯蕴天; 张宏军; 郝文宁

    2016-01-01

    Traditional methods of natural language processing input a good deal of handmade features into statistics learning models to process the text.At present,conditional random field model performed well in many natural language processing tasks,but the way of handmaking features and huge number of features made it more difficult to build the model,reduced the speed of model computing,and generated overfitting phenomenon.To solve these problems mentioned above,this paper intro-duced a novel conditional random field model extended by tensor.It designed complicated features automatically,reduced the workloads of handmaking features,used the Tucker decomposition algorithm to speed the model,and could be applied in many natural language processing tasks.Experiments show that the model can perform better in many natural language processing tasks than traditional conditional random field model if using the same elementary features.%传统的自然语言处理方法是将大量手工制定的特征输入到统计学习模型中,以完成文本的加工处理。条件随机场模型在多种自然语言处理任务中都取得了较好的效果,但手工特征制定的方式以及庞大的特征数量增加了模型建立的难度,降低了模型运算的速度,同时易使模型“过拟合”。为了解决上述问题,提出一种张量扩展的条件随机场模型,利用张量变换自动构建出复杂的特征,减少了手工特征制定的工作量,并使用Tucker分解算法加速模型,得到的模型可用于多种自然语言处理任务。实验表明,在提取相同基本特征的前提下,与传统的条件随机场模型相比,模型在多种自然语言处理任务中的性能都有所提高,具有一定的使用价值。

  13. The Influence of Content on Adult L2 Learners' Task Motivation: An Interest Theory Perspective

    Science.gov (United States)

    Poupore, Glen

    2014-01-01

    This study investigates the influence of content-related conditions on adult second language learners' task motivation during interactive tasks. It also aims to identify what is referred to as interestingness conditions within task content, that is, elements that are intrinsically interesting to most individuals. The investigation was conducted…

  14. Practice increases procedural errors after task interruption.

    Science.gov (United States)

    Altmann, Erik M; Hambrick, David Z

    2017-05-01

    Positive effects of practice are ubiquitous in human performance, but a finding from memory research suggests that negative effects are possible also. The finding is that memory for items on a list depends on the time interval between item presentations. This finding predicts a negative effect of practice on procedural performance under conditions of task interruption. As steps of a procedure are performed more quickly, memory for past performance should become less accurate, increasing the rate of skipped or repeated steps after an interruption. We found this effect, with practice generally improving speed and accuracy, but impairing accuracy after interruptions. The results show that positive effects of practice can interact with architectural constraints on episodic memory to have negative effects on performance. In practical terms, the results suggest that practice can be a risk factor for procedural errors in task environments with a high incidence of task interruption. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  15. The Effect of Orthographic Neighborhood in the Reading Span Task

    Science.gov (United States)

    Robert, Christelle; Postal, Virginie; Mathey, Stéphanie

    2015-01-01

    This study aimed at examining whether and to what extent orthographic neighborhood of words influences performance in a working memory span task. Twenty-five participants performed a reading span task in which final words to be memorized had either no higher frequency orthographic neighbor or at least one. In both neighborhood conditions, each…

  16. Novice supervisors' tasks and training

    DEFF Research Database (Denmark)

    Nielsen, Jan; Jacobsen, Claus Haugaard; Mathiesen, Birgit Bork

    2012-01-01

    were confronted with complicated jobs, e.g., group, internal and interdisciplinary supervision, but were not prepared, i.e. trained, prior to these tasks. These findings imply that more training is needed for novice supervisors. Preferably, this training should be introduced before, or at least...... parallel to, the first supervisor tasks, preparing the novice supervisors for the often complicated tasks they are meeting....

  17. Principles of Communicative Task Design.

    Science.gov (United States)

    Nunan, David

    The use of the learning task as a basic planning and instructional tool for communicative second language instruction is discussed, and considerations and procedures for designing such tasks are outlined. A task is defined as a piece of classroom work that involves learners in comprehending, manipulating, producing, or interacting in the target…

  18. TASK: Let's Have a Party!

    Science.gov (United States)

    Rees, James

    2012-01-01

    In this article, the author describes a creative way to demystify contemporary art for students. TASK is artist Oliver Herring's creation, where participants actively interpret instructions found on little pieces of paper--what he calls "tasks." An art classroom has all the key ingredients for a TASK event: (1) people; (2) materials; (3) space;…

  19. TASK: Let's Have a Party!

    Science.gov (United States)

    Rees, James

    2012-01-01

    In this article, the author describes a creative way to demystify contemporary art for students. TASK is artist Oliver Herring's creation, where participants actively interpret instructions found on little pieces of paper--what he calls "tasks." An art classroom has all the key ingredients for a TASK event: (1) people; (2) materials; (3) space;…

  20. Self-Control of Task Difficulty during Training Enhances Motor Learning of a Complex Coincidence-Anticipation Task

    Science.gov (United States)

    Andrieux, Mathieu; Danna, Jeremy; Thon, Bernard

    2012-01-01

    The aim of the present work was to analyze the influence of self-controlled task difficulty on motor learning. Participants had to intercept three targets falling at different velocities by displacing a stylus above a digitizer. Task difficulty corresponded to racquet width. Half the participants (self-control condition) could choose the racquet…

  1. Detection of Explanation Obstacles in Scientific Texts: The Effect of an Understanding Task vs. an Experiment Task

    Science.gov (United States)

    Morgado, Júlia; Otero, José; Vaz-Rebelo, Piedade; Sanjosé, Vicente; Caldeira, Helena

    2014-01-01

    The aim of this study is to analyse the effect of tasks on the detection of explanation obstacles when secondary school students read scientific texts. Students were instructed to read short passages under different task conditions, and to ask questions if necessary. Obstacle detection was operationalised in terms of the type of questions asked by…

  2. Self-Control of Task Difficulty during Training Enhances Motor Learning of a Complex Coincidence-Anticipation Task

    Science.gov (United States)

    Andrieux, Mathieu; Danna, Jeremy; Thon, Bernard

    2012-01-01

    The aim of the present work was to analyze the influence of self-controlled task difficulty on motor learning. Participants had to intercept three targets falling at different velocities by displacing a stylus above a digitizer. Task difficulty corresponded to racquet width. Half the participants (self-control condition) could choose the racquet…

  3. Task relevance regulates the interaction between reward expectation and emotion.

    Science.gov (United States)

    Wei, Ping; Kang, Guanlan

    2014-06-01

    In the present study, we investigated the impact of reward expectation on the processing of emotional facial expression using a cue-target paradigm. A cue indicating the reward condition of each trial (incentive vs. non-incentive) was followed by the presentation of a picture of an emotional face, the target. Participants were asked to discriminate the emotional expression of the target face in Experiment 1, to discriminate the gender of the target face in Experiment 2, and to judge a number superimposed on the center of the target face as even or odd in Experiment 3, rendering the emotional expression of the target face as task relevant in Experiment 1 but task irrelevant in Experiments 2 and 3. Faster reaction times (RTs) were observed in the monetary incentive condition than in the non-incentive condition, demonstrating the effect of reward on facilitating task concentration. Moreover, the reward effect (i.e., RTs in non-incentive conditions versus incentive conditions) was larger for emotional faces than for neutral faces when emotional expression was task relevant but not when it was task irrelevant. The findings suggest that top-down incentive motivation biased attentional processing toward task-relevant stimuli, and that task relevance played an important role in regulating the influence of reward expectation on the processing of emotional stimuli.

  4. A Mozart effect for women on a mental rotations task.

    Science.gov (United States)

    Gilleta, Karen S; Vrbancic, Mirna I; Elias, Lorin J; Saucier, Deborah M

    2003-06-01

    During the past decade, there have been numerous reports of a brief, but statistically significant, improvement in immediate spatial-temporal performance after listening to 10 min. of Mozart's Sonata K.448, known as the "Mozart effect." The purpose of the present study was to assess whether production of the effect is influenced by length of listening conditions or sex. Each of 52 right-handed participants (26 females, 26 males) completed a paper-folding and cutting task and a Mental Rotations task following a listening condition in which the Mozart sonata was played and a silent condition (no music was played). A significant 3-way interaction among sex, listening condition, and task indicated that an effect was present only for women on the Mental Rotations task. As such, researchers should investigate the role of sex in production of the Mozart effect.

  5. Ranking Performance Measures in Multi-Task Agencies

    DEFF Research Database (Denmark)

    Christensen, Peter Ove; Sabac, Florin; Tian, Joyce

    We derive sufficient conditions for ranking performance evaluation systems in multi-task agency models using both optimal and linear contracts in terms of a second-order stochastic dominance (SSD) condition on the likelihood ratios. The SSD condition can be replaced by a variance-covariance matrix...

  6. Ranking Performance Measures in Multi-Task Agencies

    DEFF Research Database (Denmark)

    Christensen, Peter Ove; Sabac, Florin; Tian, Joyce

    We derive sufficient conditions for ranking performance evaluation systems in multi-task agency models using both optimal and linear contracts in terms of a second-order stochastic dominance (SSD) condition on the likelihood ratios. The SSD condition can be replaced by a variance-covariance matrix...

  7. Brain metabolism after extended training in a fear conditioning task

    OpenAIRE

    Conejo Jiménez, Nélida María; López Ramírez, Matías; González Pardo, Héctor; Cantora Castellanos, Raul; Begega Losa, María Azucena; López Álvarez, Laudino; Vallejo Seco, Guillermo; Arias Pérez, Jorge Luis

    2005-01-01

    El condicionamiento Pavloviano del miedo (CPM) es uno de los paradigmas conductuales más usados para estudiar la neurobiología del aprendizaje y la memoria. Se entrenaron ratas en una tarea de supresión condicionada, que recibieron tres (entrenamiento limitado) u ocho sesiones de condicionamiento (entrenamiento prolongado). Ambos grupos llegaron a suprimir la conducta de presión de una palanca cuando se estableció el condicionamiento. Posteriormente, se analizó el metabolismo neuronal de regi...

  8. Keep flexible - Keep switching! The influence of forced task switching on voluntary task switching.

    Science.gov (United States)

    Fröber, Kerstin; Dreisbach, Gesine

    2017-05-01

    Goal directed behavior depends on a dynamic balance between cognitive flexibility and stability. Identifying factors that modulate the balance between these control states is therefore of major interest for the understanding of human action control. In two experiments we used a hybrid paradigm combining forced- and free-choice task switching and measured spontaneous voluntary switch rate (VSR) as an indicator of cognitive flexibility. In Experiment 1 participants were free to choose a given task on 75%, 50%, or 25% of all trials. In the remaining forced-choice trials task repetitions and switches were roughly equally distributed. Results showed that VSR increases with increasing proportion of forced choices. To clarify whether the frequency of forced choices per se or the frequency of forced task switches in particular drives this effect we conducted Experiment 2. In a fully orthogonal between design participants were free to choose a given task on 75% or 25% of all trials with a predetermined switch rate in the remaining forced-choice trials of 75% or 25%, respectively. Results revealed an interaction of both manipulations: The highest VSR was found for the combination of 75% forced-choice trials with 75% forced switch rate, while VSR for 75% forced-choice trials with 25% forced switch rate was still higher than VSRs in both conditions with 25% forced-choice trials. This suggests that a context of frequent forced task switching changes global control parameters towards more flexible behavior. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. The impact of a concurrent motor task on auditory and visual temporal discrimination tasks.

    Science.gov (United States)

    Mioni, Giovanna; Grassi, Massimo; Tarantino, Vincenza; Stablum, Franca; Grondin, Simon; Bisiacchi, Patrizia S

    2016-04-01

    Previous studies have shown the presence of an interference effect on temporal perception when participants are required to simultaneously execute a nontemporal task. Such interference likely has an attentional source. In the present work, a temporal discrimination task was performed alone or together with a self-paced finger-tapping task used as concurrent, nontemporal task. Temporal durations were presented in either the visual or the auditory modality, and two standard durations (500 and 1,500 ms) were used. For each experimental condition, the participant's threshold was estimated and analyzed. The mean Weber fraction was higher in the visual than in the auditory modality, but only for the subsecond duration, and it was higher with the 500-ms than with the 1,500-ms standard duration. Interestingly, the Weber fraction was significantly higher in the dual-task condition, but only in the visual modality. The results suggest that the processing of time in the auditory modality is likely automatic, but not in the visual modality.

  10. [Autoimmune processes after long-term low-level exposure to electromagnetic fields (the results of an experiment). Part 2. General scheme and conditions of the experiment. Development of RF exposure conditions complying with experimental tasks. Animal's status during the long-term exposure].

    Science.gov (United States)

    Grigor'ev, Iu G; Grigor'ev, O A; Merkulov, A V; Shafirkin, A V; Vorob'ev, A A

    2010-01-01

    This paper describes the conditions for handling and exposure of experimental animals (Wistar rats) and methods used in the study of immunological effects of long-term low-level (500 microW/cm2) exposure to radiofrequency (2450 MHz) electromagnetic fields, performed under auspices of the World Health Organization.

  11. Visual Attention Allocation Between Robotic Arm and Environmental Process Control: Validating the STOM Task Switching Model

    Science.gov (United States)

    Wickens, Christopher; Vieanne, Alex; Clegg, Benjamin; Sebok, Angelia; Janes, Jessica

    2015-01-01

    Fifty six participants time shared a spacecraft environmental control system task with a realistic space robotic arm control task in either a manual or highly automated version. The former could suffer minor failures, whose diagnosis and repair were supported by a decision aid. At the end of the experiment this decision aid unexpectedly failed. We measured visual attention allocation and switching between the two tasks, in each of the eight conditions formed by manual-automated arm X expected-unexpected failure X monitoring- failure management. We also used our multi-attribute task switching model, based on task attributes of priority interest, difficulty and salience that were self-rated by participants, to predict allocation. An un-weighted model based on attributes of difficulty, interest and salience accounted for 96 percent of the task allocation variance across the 8 different conditions. Task difficulty served as an attractor, with more difficult tasks increasing the tendency to stay on task.

  12. An optimal scheduling algorithm based on task duplication

    Institute of Scientific and Technical Information of China (English)

    Ruan Youlin; Liu Gan; Zhu Guangxi; Lu Xiaofeng

    2005-01-01

    When the communication time is relatively shorter than the computation time for every task, the task duplication based scheduling (TDS) algorithm proposed by Darbha and Agrawal generates an optimal schedule. Park and Choe also proposed an extended TDS algorithm whose optimality condition is less restricted than that of TDS algorithm, but the condition is very complex and is difficult to satisfy when the number of tasks is large. An efficient algorithm is proposed whose optimality condition is less restricted and simpler than both of the algorithms, and the schedule length is also shorter than both of the algorithms. The time complexity of the proposed algorithm is O ( v2 ), where v represents the number of tasks.

  13. Task Analyses for Difficult-to-Assess Collective Tasks

    Science.gov (United States)

    2014-02-01

    Counterintelligence and Human Intelligence Analysis and Production (34-4-1305) • Conduct Counterintelligence and Human Intelligence Analysis (34-4...Research Product 2014-05 Task Analyses for Difficult-to-Assess Collective Tasks Jonathan J. Bryson Rachel D. Barney...Christina K. Curnow Trevor M. Conrad Arnold L. Leonard Heidi Keller-Glaze ICF International Jennifer S. Tucker Christopher L. Vowels

  14. Rate of learning and asymptotic performance in an automatization task and the relation to reading.

    Science.gov (United States)

    Hecht, Rozalia; Crewther, David; Crewther, Sheila

    2004-12-01

    In the present study, direct evidence was sought linking cognitive automatic processing with reading in the general adult population. Reading speed on single-task performance and dual-task performance were compared. A total of 18 adults without dyslexia participated (7 men and 11 women, age M=25.3 yr., SD=2.7). Participants initially were trained in single-task mode on two types of tasks. The first was a central alphanumeric equation task (true or false), which comprised 3 subtests of increasing difficulty, ranging from an easily automated task to a varied and unpredictable mathematical operation. The second task was a peripheral pattern subitization task for which stimulus exposure time was related to performance. Finally, participants received dual-task training, which required simultaneous processing of both tasks. Slower reading speed was significantly related to rate of learning and speed of performance on predictable alphanumeric operations in dual-task conditions. There was no effect of reading speed on performance in the varied alphanumeric task. Faster readers were no better than slower readers on the pattern-subitization task. These findings suggest that faster readers automatized the predictable alphanumeric task more rapidly than slower readers and hence were better able to cope with the dual-task condition.

  15. Contingent muscular tension during a choice reaction task.

    Science.gov (United States)

    Araki, Masanobu; Choshi, Koji

    2006-06-01

    This study examined the effects of contingent muscular tension on a choice reaction task, and especially, the effects various amounts of muscular tension have on the information processing of choice reaction time. The reactive movement task included a choice reaction task. Ten right-handed healthy men (ages 18 to 19 years) underwent trials with stimulus presentation probabilities of 50% and 20% on the muscular tension task and choice reaction tasks. The conditions for the muscular tension tasks were divided into seven different conditions: 0%, 10%, 20%, 30%, 40%, 50%, and 60% of maximum voluntary contraction. On these tasks, subjects performed isometric contraction of the biceps brachii. The choice reaction task was a rapid extension of the left or right knee as a choice reaction. Measures were choice reaction time, movement time, and total reaction time. Analysis indicated that shortening choice reaction time of the left and right feet was observed under 10% muscular tension of maximum strength. Muscular tension appreciably influenced information processing, including choice reaction time. Muscular tension did not affect movement time. Results are discussed with respect to previous research and the optimal muscular tension for best performance.

  16. Emotional reactivity and awareness of task performance in Alzheimer's disease.

    Science.gov (United States)

    Mograbi, Daniel C; Brown, Richard G; Salas, Christian; Morris, Robin G

    2012-07-01

    Lack of awareness about performance in tasks is a common feature of Alzheimer's disease. Nevertheless, clinical anecdotes have suggested that patients may show emotional or behavioural responses to the experience of failure despite reporting limited awareness, an aspect which has been little explored experimentally. The current study investigated emotional reactions to success or failure in tasks despite unawareness of performance in Alzheimer's disease. For this purpose, novel computerised tasks which expose participants to systematic success or failure were used in a group of Alzheimer's disease patients (n=23) and age-matched controls (n=21). Two experiments, the first with reaction time tasks and the second with memory tasks, were carried out, and in each experiment two parallel tasks were used, one in a success condition and one in a failure condition. Awareness of performance was measured comparing participant estimations of performance with actual performance. Emotional reactivity was assessed with a self-report questionnaire and rating of filmed facial expressions. In both experiments the results indicated that, relative to controls, Alzheimer's disease patients exhibited impaired awareness of performance, but comparable differential reactivity to failure relative to success tasks, both in terms of self-report and facial expressions. This suggests that affective valence of failure experience is processed despite unawareness of task performance, which might indicate implicit processing of information in neural pathways bypassing awareness. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Caffeine improves anticipatory processes in task switching

    NARCIS (Netherlands)

    Tieges, Zoe; Snel, Jan; Kok, Albert; Wijnen, Jasper G.; Lorist, Monicque M.; Ridderinkhof, K. Richard

    We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials

  18. Caffeine improves anticipatory processes in task switching

    NARCIS (Netherlands)

    Tieges, Zoe; Snel, Jan; Kok, Albert; Wijnen, Jasper G.; Lorist, Monicque M.; Ridderinkhof, K. Richard

    2006-01-01

    We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials (e

  19. Reward expectation regulates brain responses to task-relevant and task-irrelevant emotional words: ERP evidence.

    Science.gov (United States)

    Wei, Ping; Wang, Di; Ji, Liyan

    2016-02-01

    We investigated the effect of reward expectation on the processing of emotional words in two experiments using event-related potentials (ERPs). A cue indicating the reward condition of each trial (incentive vs non-incentive) was followed by the presentation of a negative or neutral word, the target. Participants were asked to discriminate the emotional content of the target word in Experiment 1 and to discriminate the color of the target word in Experiment 2, rendering the emotionality of the target word task-relevant in Experiment 1, but task-irrelevant in Experiment 2. The negative bias effect, in terms of the amplitude difference between ERPs for negative and neutral targets, was modulated by the task-set. In Experiment 1, P31 and early posterior negativity revealed a larger negative bias effect in the incentive condition than that in the non-incentive condition. However, in Experiment 2, P31 revealed a diminished negative bias effect in the incentive condition compared with that in the non-incentive condition. These results indicate that reward expectation improves top-down attentional concentration to task-relevant information, with enhanced sensitivity to the emotional content of target words when emotionality is task-relevant, but with reduced differential brain responses to emotional words when their content is task-irrelevant. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  20. Decision paths in complex tasks

    Science.gov (United States)

    Galanter, Eugene

    1991-01-01

    Complex real world action and its prediction and control has escaped analysis by the classical methods of psychological research. The reason is that psychologists have no procedures to parse complex tasks into their constituents. Where such a division can be made, based say on expert judgment, there is no natural scale to measure the positive or negative values of the components. Even if we could assign numbers to task parts, we lack rules i.e., a theory, to combine them into a total task representation. We compare here two plausible theories for the amalgamation of the value of task components. Both of these theories require a numerical representation of motivation, for motivation is the primary variable that guides choice and action in well-learned tasks. We address this problem of motivational quantification and performance prediction by developing psychophysical scales of the desireability or aversiveness of task components based on utility scaling methods (Galanter 1990). We modify methods used originally to scale sensory magnitudes (Stevens and Galanter 1957), and that have been applied recently to the measure of task 'workload' by Gopher and Braune (1984). Our modification uses utility comparison scaling techniques which avoid the unnecessary assumptions made by Gopher and Braune. Formula for the utility of complex tasks based on the theoretical models are used to predict decision and choice of alternate paths to the same goal.

  1. Putting Mathematical Tasks into Context

    Science.gov (United States)

    Nagle, Courtney R.; Styers, Jodie L.

    2015-01-01

    Although many factors affect students' mathematical activity during a lesson, the teacher's selection and implementation of tasks is arguably the most influential in determining the level of student engagement. Mathematical tasks are intended to focus students' attention on a particular mathematical concept and it is the careful developing and…

  2. Human-System task integration

    NARCIS (Netherlands)

    Schraagen, J.M.C.

    2005-01-01

    The Dutch Ministry of Defence research programme Human-System Task Integration aims at acquiring knowledge for the optimal cooperation between human and computer, under the following constraints: freedom of choice in decisions to automate and multiple, dynamic task distributions. This paper describe

  3. Designing for dynamic task allocation

    NARCIS (Netherlands)

    Dongen, C.J.G. van; Maanen, P.P. van

    2005-01-01

    Future platforms are envisioned in which human-machine teams are able to share and trade tasks as demands in situations change. It seems that human-machine coordination has not received the attention it deserves by past and present approaches to task allocation. In this paper a simple way to make co

  4. Creativity, Overinclusion, and Everyday Tasks

    Science.gov (United States)

    Ottemiller, Dylan D.; Elliott, Colette Seter; Giovannetti, Tania

    2014-01-01

    This study examined relations between creative thinking and performance on routine, everyday tasks. Results were considered in light of past research on the putative relation between creativity and schizophrenia/psychotic thinking. Thirty healthy undergraduates completed the Alternative Uses Task, a measure of divergent thinking, and the 2 × 3…

  5. Task modeling for collaborative authoring

    NARCIS (Netherlands)

    Veer, van der Gerrit; Kulyk, Olga; Vyas, Dhaval; Kubbe, Onno; Ebert, Achim; Dittmar, A.; Forbrig, P.

    2011-01-01

    Motivation –Task analysis for designing modern collaborative work needs a more fine grained approach. Especially in a complex task domain, like collaborative scientific authoring, when there is a single overall goal that can only be accomplished only by collaboration between multiple roles, each req

  6. Influence of postnatal glucocorticoids on hippocampal-dependent learning varies with elevation patterns and administration methods

    Science.gov (United States)

    2017-05-22

    Kraszpulski* Michael B. Hennessy* 5e. TASK NUMBER 5f. WORK UNIT NUMBER H0S6 (53290829) 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES...Colonel Glenn Hwy Bldg. 840 E200.06 Dayton OH 45435 Wright-Patterson AFB OH 45433 8. PERFORMING ORGANIZATION ...glucocorticoid medications prescribed in childhood are discussed. 15. SUBJECT TERMS Glucocorticoids, Development , Eyeblink Conditioning, Trace Conditioning

  7. The Influence of Complexity in Monologic versus Dialogic Tasks in Dutch L2

    Science.gov (United States)

    Michel, Marije C.; Kuiken, Folkert; Vedder, Ineke

    2007-01-01

    This study puts the Cognition Hypothesis (Robinson 2005) to the test with respect to its predictions of the effects of changes in task complexity ([plus or minus] few elements) and task condition ([plus or minus] monologic) on L2 performance. 44 learners of Dutch performed both a simple and a complex oral task in either a monologic or a dialogic…

  8. Relation between temporal perception and inhibitory control in the Go/No-Go task.

    Science.gov (United States)

    Brown, Scott W; Perreault, Sara T

    2017-02-01

    This research was designed to replicate and extend findings concerning bidirectional interference between concurrent timing and inhibition tasks reported previously. Subjects performed serial temporal production and Go/No-Go (GNG) tasks under single-task and dual-task conditions in two experiments. The degree of inhibitory control required in the GNG tasks was manipulated by varying the proportion of go and no-go stimuli (experiment 1) and by instructing subjects to devote different amounts of attention to the dual tasks (experiment 2). The dual-task conditions in both experiments showed a pattern of mutual interference in which each task interfered with the other. In experiment 1, concurrent timing interfered more strongly with performance on a high inhibitory-demand GNG task compared with a low inhibitory-demand GNG task. In experiment 2, concurrent timing and GNG performance displayed a reciprocity effect in which greater attentiveness to one task improved performance for that task but diminished performance for the other task, and vice versa. These results support the view that temporal processing and inhibitory control depend upon a common pool of attentional resources, and point to the GNG task as a reliable research tool for investigators studying the role of attentional processes in time perception. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Distinguishing Reconfiguration and Compound-cue Retrieval in Task Switching

    Directory of Open Access Journals (Sweden)

    Gordon D Logan

    2010-10-01

    Full Text Available Many researchers claim that task switching requires reconfiguration of the cognitive system. Others claim that task switching involves cue-based memory retrieval processes and not reconfiguration. We evaluate these competing claims by developing both reconfiguration and cue-based memory models in a common theoretical framework and by fitting the models to' target functions', which show how performance on individual target stimuli varies depending on the task subjects perform on the targets. Our analyses show that the process of compound-cue retrieval – using the task cue and the target as joint retrieval cues to select a response from memory – is sufficient to explain target functions for parity and magnitude judgments of digits and that reconfiguration does not seem to add anything to the explanation. We address the generality of this conclusion and speculate about the conditions under which reconfiguration may be necessary for task switching.

  10. Divergent Perceptions of Telecollaborative Language Learning Tasks: Task-as-Workplan vs. Task-as-Process

    National Research Council Canada - National Science Library

    Dooly, Melinda

    2011-01-01

    ... place. The task design and its implementation are key elements for efficient language learning to develop--a carefully designed task or activity that requires off- and online co-construction of knowledge not only provides opportunities for target language practice, it also helps integrate language use as the means for shared knowledge-build...

  11. Ergonomic factors on task performance in laparoscopic surgery training.

    Science.gov (United States)

    Xiao, D J; Jakimowicz, Jack J; Albayrak, A; Goossens, R H M

    2012-05-01

    This paper evaluates the effect of ergonomic factors on task performance and trainee posture during laparoscopic surgery training. Twenty subjects without laparoscopic experience were allotted into 2 groups. Group 1 was trained under the optimal ergonomic simulation setting according to current ergonomic guidelines (Condition A). Group 2 was trained under non-optimal ergonomic simulation setting that can often be observed during training in a skills lab (Condition B). Posture analysis showed that the subjects held a much more neutral posture under Condition A than under Condition B (poptimal ergonomic simulation setting leads to better task performance. In addition, no significant differences of task performance, for Groups 1 and 2 using the same test setting were found. However, better performance was observed for Group 1. It can be concluded that the optimal and non-optimal training setting have different learning effects on trainees' skill learning.

  12. Constrained Task Assignment and Scheduling On Networks of Arbitrary Topology

    Science.gov (United States)

    Jackson, Justin Patrick

    solves this problem. The algorithm is correct, complete, outputs time optimal schedules, and has low average-case time complexity. Separation of the task assignment and task scheduling problems is exploited here to ameliorate the effects of an incomplete communication network. The mission-modeling conditions that allow this and the benefits gained are discussed in detail. It is shown that the distributed task assignment and task scheduling algorithms developed here can operate concurrently and maintain their correctness, completeness, and optimality properties.

  13. Objective Motion Cueing Criteria Investigation Based on Three Flight Tasks

    Science.gov (United States)

    Zaal, Petrus M. T.; Schroeder, Jeffery A.; Chung, William W.

    2015-01-01

    This paper intends to help establish fidelity criteria to accompany the simulator motion system diagnostic test specified by the International Civil Aviation Organization. Twelve air- line transport pilots flew three tasks in the NASA Vertical Motion Simulator under four different motion conditions. The experiment used three different hexapod motion configurations, each with a different tradeoff between motion filter gain and break frequency, and one large motion configuration that utilized as much of the simulator's motion space as possible. The motion condition significantly affected: 1) pilot motion fidelity ratings, and sink rate and lateral deviation at touchdown for the approach and landing task, 2) pilot motion fidelity ratings, roll deviations, maximum pitch rate, and number of stick shaker activations in the stall task, and 3) heading deviation after an engine failure in the takeoff task. Significant differences in pilot-vehicle performance were used to define initial objective motion cueing criteria boundaries. These initial fidelity boundaries show promise but need refinement.

  14. TASK 2: QUENCH ZONE SIMULATION

    Energy Technology Data Exchange (ETDEWEB)

    Fusselman, Steve

    2015-09-30

    Aerojet Rocketdyne (AR) has developed an innovative gasifier concept incorporating advanced technologies in ultra-dense phase dry feed system, rapid mix injector, and advanced component cooling to significantly improve gasifier performance, life, and cost compared to commercially available state-of-the-art systems. A key feature of the AR gasifier design is the transition from the gasifier outlet into the quench zone, where the raw syngas is cooled to ~ 400°C by injection and vaporization of atomized water. Earlier pilot plant testing revealed a propensity for the original gasifier outlet design to accumulate slag in the outlet, leading to erratic syngas flow from the outlet. Subsequent design modifications successfully resolved this issue in the pilot plant gasifier. In order to gain greater insight into the physical phenomena occurring within this zone, AR developed a cold flow simulation apparatus with Coanda Research & Development with a high degree of similitude to hot fire conditions with the pilot scale gasifier design, and capable of accommodating a scaled-down quench zone for a demonstration-scale gasifier. The objective of this task was to validate similitude of the cold flow simulation model by comparison of pilot-scale outlet design performance, and to assess demonstration scale gasifier design feasibility from testing of a scaled-down outlet design. Test results did exhibit a strong correspondence with the two pilot scale outlet designs, indicating credible similitude for the cold flow simulation device. Testing of the scaled-down outlet revealed important considerations in the design and operation of the demonstration scale gasifier, in particular pertaining to the relative momentum between the downcoming raw syngas and the sprayed quench water and associated impacts on flow patterns within the quench zone. This report describes key findings from the test program, including assessment of pilot plant configuration simulations relative to actual

  15. Effects of state anxiety on performance using a task-switching paradigm: an investigation of attentional control theory.

    Science.gov (United States)

    Derakshan, Nazanin; Smyth, Sinéad; Eysenck, Michael W

    2009-12-01

    Low- and high-anxious participants performed arithmetical tasks under task-switching or nontask-switching conditions. These tasks were low or high in complexity. The task on each trial was either explicitly cued or not cued. We assumed that demands on attentional control would be greater in the task-switching condition than in the nontask-switching condition, and would be greater with high-complexity tasks than with low-complexity ones. We also assumed that demands on attentional control would be greater when cues were absent rather than present. According to attentional control theory (Eysenck, Derakshan, Santos, & Calvo, 2007), anxiety impairs attentional control processes required to shift attention optimally within and between tasks. We predicted that there would be greater negative effects of high state anxiety in the task-switching condition than in the nontask-switching condition. Our theoretical predictions were supported, suggesting that state anxiety reduces attentional control.

  16. Training Techniques for Visual Search in Complex Task Environments.

    Science.gov (United States)

    Guznov, Svyatoslav; Matthews, Gerald; Warm, Joel S; Pfahler, Marc

    2017-06-01

    The goal for this study was to evaluate several visual search training techniques in an unmanned aerial vehicle (UAV) simulated task environment. Operators controlling remote unmanned vehicles often must perform complex visual search tasks (e.g., target search). These tasks may pose substantial demands on the operator due to various environmental factors. Visual search training may reduce errors and mitigate stress, but the most effective form of training has not been determined. Participants were assigned to one of four training conditions: target, cue, visual scanning, or control. After the training, the effectiveness of the training techniques was tested during a 30-minute simulated UAV flight. A secondary task manipulation was included to further simulate the demands of a realistic UAV control and target search task. Subjective stress and fatigue were also assessed. Target training produced superior target search performances in more hits and fewer false alarms (FAs) when compared to the control condition. The visual scanning and cue trainings were moderately effective. Only target training performance was vulnerable to the secondary task load. The task was stressful, but training did not mitigate stress response. Training participants on the target and the cue appearance as well as active scanning of the visual field is promising for promoting effective target search for this simulated UAV environment. These training techniques could be used in preparation for intelligence, surveillance, and reconnaissance (ISR) missions that involve target search, especially where target appearance change is likely.

  17. Modeling of Task Planning for Multirobot System Using Reputation Mechanism

    Directory of Open Access Journals (Sweden)

    Zhiguo Shi

    2014-01-01

    Full Text Available Modeling of task planning for multirobot system is developed from two parts: task decomposition and task allocation. In the part of task decomposition, the conditions and processes of decomposition are elaborated. In the part of task allocation, the collaboration strategy, the framework of reputation mechanism, and three types of reputations are defined in detail, which include robot individual reputation, robot group reputation, and robot direct reputation. A time calibration function and a group calibration function are designed to improve the effectiveness of the proposed method and proved that they have the characteristics of time attenuation, historical experience related, and newly joined robot reward. Tasks attempt to be assigned to the robot with higher overall reputation, which can help to increase the success rate of the mandate implementation, thereby reducing the time of task recovery and redistribution. Player/Stage is used as the simulation platform, and three biped-robots are established as the experimental apparatus. The experimental results of task planning are compared with the other allocation methods. Simulation and experiment results illustrate the effectiveness of the proposed method for multi-robot collaboration system.

  18. Task Space Tracking for Manipulators

    Directory of Open Access Journals (Sweden)

    Olav Egeland

    1985-04-01

    Full Text Available For the purpose of controlling a manipulator in the task space, a linear model with task space position and velocity as state variables can be developed. This is done by means of exact compensation of the state-space model non-linearities using non-linear feedback. In this paper, feedback control for this linear state space model is developed using optimal control theory. Integral action is included to compensate for unmodeled forces and torques. In the resulting control system, the problem of transforming the task space trajectory to the joint space is avoided, and the controller parameters can be chosen to satisfy requirements specified in the task space. Simulation experiments show promising results.

  19. Annual Progress report - General Task

    Energy Technology Data Exchange (ETDEWEB)

    Wesnousky, S.G.

    1993-09-30

    This report provides a summary of progress for the project {open_quotes}Evaluation of the Geologic Relations and Seismotectonic Stability of the Yucca Mountain Area, Nevada Nuclear Waste Site Investigation (NNWSI).{close_quotes} A similar report was previously provided for the period of 1 October 1991 to 30 September 1992. The report initially covers the activities of the General Task and is followed by sections that describe the progress of the other ongoing tasks.

  20. Why trace and delay conditioning are sometimes (but not always) hippocampal dependent: a computational model.

    Science.gov (United States)

    Moustafa, Ahmed A; Wufong, Ella; Servatius, Richard J; Pang, Kevin C H; Gluck, Mark A; Myers, Catherine E

    2013-02-01

    A recurrent-network model provides a unified account of the hippocampal region in mediating the representation of temporal information in classical eyeblink conditioning. Much empirical research is consistent with a general conclusion that delay conditioning (in which the conditioned stimulus CS and unconditioned stimulus US overlap and co-terminate) is independent of the hippocampal system, while trace conditioning (in which the CS terminates before US onset) depends on the hippocampus. However, recent studies show that, under some circumstances, delay conditioning can be hippocampal-dependent and trace conditioning can be spared following hippocampal lesion. Here, we present an extension of our prior trial-level models of hippocampal function and stimulus representation that can explain these findings within a unified framework. Specifically, the current model includes adaptive recurrent collateral connections that aid in the representation of intra-trial temporal information. With this model, as in our prior models, we argue that the hippocampus is not specialized for conditioned response timing, but rather is a general-purpose system that learns to predict the next state of all stimuli given the current state of variables encoded by activity in recurrent collaterals. As such, the model correctly predicts that hippocampal involvement in classical conditioning should be critical not only when there is an intervening trace interval, but also when there is a long delay between CS onset and US onset. Our model simulates empirical data from many variants of classical conditioning, including delay and trace paradigms in which the length of the CS, the inter-stimulus interval, or the trace interval is varied. Finally, we discuss model limitations, future directions, and several novel empirical predictions of this temporal processing model of hippocampal function and learning.

  1. Dual-tasking postural control in patients with right brain damage.

    Science.gov (United States)

    Bourlon, Clémence; Lehenaff, Laurent; Batifoulier, Cécile; Bordier, Aurélie; Chatenet, Aurélia; Desailly, Eric; Fouchard, Christian; Marsal, Muriel; Martinez, Marianne; Rastelli, Federica; Thierry, Anaïs; Bartolomeo, Paolo; Duret, Christophe

    2014-01-01

    The control of dual-tasking effects is a daily challenge in stroke neurorehabilitation. It maybe one of the reasons why there is poor functional prognosis after a stroke in the right hemisphere, which plays a dominant role in posture control. The purpose of this study was to explore cognitive motor interference in right brain-lesioned and healthy subjects maintaining a standing position while performing three different tasks: a control task, a simple attentional task and a complex attentional task. We measured the sway area of the subjects on a force platform, including the center of pressure and its displacements. Results showed that stroke patients presented a reduced postural sway compared to healthy subjects, who were able to maintain their posture while performing a concomitant attentional task in the same dual-tasking conditions. Moreover, in both groups, the postural sway decreased with the increase in attentional load from cognitive tasks. We also noticed that the stability of stroke patients in dual-tasking conditions increased together with the weight-bearing rightward deviation, especially when the attentional load of the cognitive tasks and lower limb motor impairments were high. These results suggest that stroke patients and healthy subjects adopt a similar postural regulation pattern aimed at maintaining stability in dual-tasking conditions involving a static standing position and different attention-related cognitive tasks. Our results indicate that attention processes might facilitate static postural control.

  2. Texting and walking: effect of environmental setting and task prioritization on dual-task interference in healthy young adults.

    Science.gov (United States)

    Plummer, Prudence; Apple, Sarah; Dowd, Colleen; Keith, Eliza

    2015-01-01

    Recent studies have shown that young adults significantly reduce their gait speed and weave more when texting while walking. Previous research has not examined the simultaneous dual-task effects on texting performance, therefore, the attention prioritization strategy used by young adults while texting and walking is not currently known. Moreover, it is not known whether laboratory-based studies accurately reflect texting and walking performance in the real world. This study compared dual-task interference during texting and walking between laboratory and real-world settings, and examined the ability of young adults to flexibly prioritize their attention between the two tasks in each environment. Texting and walking were assessed in single-task and three dual-task conditions (no-priority, gait-priority, texting-priority) in the lab and a University Student Center, in 32 healthy young adults. Dual-task effects on gait speed, texting speed, and texting accuracy were significant, but did not significantly differ between the two environments. Young adults were able to flexibly prioritize their attention between texting and walking, according to specific instruction, and this ability was not influenced by environmental setting. In the absence of instructions, young adults prioritized the texting task in the low-distraction environment, but displayed more equal focus between tasks in the real world. The finding that young adults do not significantly modify their texting and walking behavior in high-distraction environments lends weight to growing concerns about cell phone use and pedestrian safety.

  3. Inductive System Monitors Tasks

    Science.gov (United States)

    2008-01-01

    The Inductive Monitoring System (IMS) software developed at Ames Research Center uses artificial intelligence and data mining techniques to build system-monitoring knowledge bases from archived or simulated sensor data. This information is then used to detect unusual or anomalous behavior that may indicate an impending system failure. Currently helping analyze data from systems that help fly and maintain the space shuttle and the International Space Station (ISS), the IMS has also been employed by data classes are then used to build a monitoring knowledge base. In real time, IMS performs monitoring functions: determining and displaying the degree of deviation from nominal performance. IMS trend analyses can detect conditions that may indicate a failure or required system maintenance. The development of IMS was motivated by the difficulty of producing detailed diagnostic models of some system components due to complexity or unavailability of design information. Successful applications have ranged from real-time monitoring of aircraft engine and control systems to anomaly detection in space shuttle and ISS data. IMS was used on shuttle missions STS-121, STS-115, and STS-116 to search the Wing Leading Edge Impact Detection System (WLEIDS) data for signs of possible damaging impacts during launch. It independently verified findings of the WLEIDS Mission Evaluation Room (MER) analysts and indicated additional points of interest that were subsequently investigated by the MER team. In support of the Exploration Systems Mission Directorate, IMS is being deployed as an anomaly detection tool on ISS mission control consoles in the Johnson Space Center Mission Operations Directorate. IMS has been trained to detect faults in the ISS Control Moment Gyroscope (CMG) systems. In laboratory tests, it has already detected several minor anomalies in real-time CMG data. When tested on archived data, IMS was able to detect precursors of the CMG1 failure nearly 15 hours in advance of

  4. Evaluation of reward-relevant learning and memory behavior with operant conditioning task in rats%奖励性操作式条件反射任务在大鼠学习记忆研究中的应用

    Institute of Scientific and Technical Information of China (English)

    石哲; 曲丽娜; 刘新民; 陈善广; 陈玲玲; 孙秀萍; 宋广青; 王琼; 常琪; 李海清; 李莹辉

    2012-01-01

    目的 将奖励性操作式条件反射方法应用于学习记忆研究.方法 首次采用奖励性操作式条件反射方法,设置单次操作训练、连续多次操作训练、信号辨识与消退四种检测模式,研究Wistar大鼠和SHR大鼠学习记忆能力.结果 奖赏训练中,SHR组鼻触次数显著增多(vs.Wistar&Donepezil,P<0.05);单次操作训练中,三组动物对操作反应的获得无显著差异;连续多次操作学习任务中,SHR组错误操作次数增多(vs.Wistar,P<0.05),奖赏获得次数减少(vs.Donepezil,P<0.001),反应准确率显著降低(vs.Wistar & Donepezil,P<0.05);信号辨识任务中SHR组错误反应次数显著增多(vs.Wistar & Donepezil,P<0.05),而反应准确率降低,组间差异有显著性( vs.Wistar & DonepezilP<0.05);消退实验中,三组动物差异无显著性.神经递质检测发现,SHR组大鼠谷氨酸[(1.0639 ±0.07086) mg/g]、乙酰胆碱[(2.7760±0.2609)μg/g]与五羟色胺[(1.2200±0.1137)μg/g]含量均显著低于Wistar组大鼠(P<0.05),多奈哌齐组大鼠乙酰胆碱含量显著增加[(3.9344±0.2747) μg/g]( vs.Wistar,P<0.05;vs.SHR,P<0.001).结论 奖励性操作式条件反射方法可作为一种正性增强条件反射检测新方法应用于大鼠学习记忆研究.%Objective To apply reward directed operant conditioning task for learning and memory research in laboratory animals. Methods Sixteen adult male SHR rats and 8 Wistar rats were included in this study. Operant conditioning procedure was used to assess the learning ability of Wistar and SHR rats with magazine training, fixed ratio, signal discrimination and extinction procedure. Results Significant difference was found in magazine training. The SHR rats performed more NP vs. Wistar rats and SHR rats treated with donepezil ( P < 0. 05 ). There was no significant difference during FR1 schedule. While in higher response ratio FR2 and FR4 schedule, the SHR group showed significantly higher error responses ( vs

  5. Common neural recruitment across diverse sustained attention tasks.

    Science.gov (United States)

    Grahn, Jessica A; Manly, Tom

    2012-01-01

    At one level "sustained attention" is simply a description of a task demand. It is often used, however, in reference to a putatively unitary capacity to remain engaged in tasks that are lengthy, dull, repetitive and/or characterised by long intervals between relevant events. Deficits in sustained attention have been reported in a range of clinical conditions. Despite this, there is paucity of well-controlled human functional imaging evidence about regions commonly recruited during diverse sustained attention tasks. Here, for the first time, we used functional magnetic resonance imaging (fMRI) to monitor brain activity patterns as healthy volunteers performed two sustained attention tasks. The first, widely used in clinical assessment, required participants to count tones separated by long unpredictable intervals. This was contrasted with a control counting condition in which tones were presented at a brisk, regular rate. The second task was the Sustained Attention to Response Test (SART) in which participants responded to sequentially presented digits with the exception of a nominated infrequent no-go target. In the control condition, no-go trials were explicitly absent, removing the requirement to maintain a readiness to withhold responses. Although there were distinct patterns of activation associated with each task relative to its control, activity common to both tasks was found in the bilateral inferior frontal operculum, anterior cingulate, and bilateral premotor cortex. Although some researchers argue for a specific role of the inferior frontal operculum in inhibition, our results are consistent with recent findings of a more general attentional role for this area. The maintenance of a goal directed stance in the absence of strong environmental facilitation is challenging and this may underpin the sensitivity of sustained attention tasks to functional difficulties in a range of clinical groups.

  6. The modality effect of ego depletion: Auditory task modality reduces ego depletion.

    Science.gov (United States)

    Li, Qiong; Wang, Zhenhong

    2016-08-01

    An initial act of self-control that impairs subsequent acts of self-control is called ego depletion. The ego depletion phenomenon has been observed consistently. The modality effect refers to the effect of the presentation modality on the processing of stimuli. The modality effect was also robustly found in a large body of research. However, no study to date has examined the modality effects of ego depletion. This issue was addressed in the current study. In Experiment 1, after all participants completed a handgrip task, one group's participants completed a visual attention regulation task and the other group's participants completed an auditory attention regulation task, and then all participants again completed a handgrip task. The ego depletion phenomenon was observed in both the visual and the auditory attention regulation task. Moreover, participants who completed the visual task performed worse on the handgrip task than participants who completed the auditory task, which indicated that there was high ego depletion in the visual task condition. In Experiment 2, participants completed an initial task that either did or did not deplete self-control resources, and then they completed a second visual or auditory attention control task. The results indicated that depleted participants performed better on the auditory attention control task than the visual attention control task. These findings suggest that altering task modality may reduce ego depletion.

  7. Polishing a Data Task: Seeking Better Assessment.

    Science.gov (United States)

    Zawojewski, Judith S.

    1996-01-01

    Shares a teacher's stages of selecting and revising a performance-assessment task focusing on data handling. Discusses selection and revision criteria, examining student work, reflecting on the task, and revising the final task. (MKR)

  8. Biomechanical Analyses of Stair-climbing while Dual-tasking

    Science.gov (United States)

    Vallabhajosula, Srikant; Tan, Chi Wei; Mukherjee, Mukul; Davidson, Austin J.; Stergiou, Nicholas

    2015-01-01

    Stair-climbing while doing a concurrent task like talking or holding an object is a common activity of daily living which poses high risk for falls. While biomechanical analyses of overground walking during dual-tasking have been studied extensively, little is known on the biomechanics of stair-climbing while dual-tasking. We sought to determine the impact of performing a concurrent cognitive or motor task during stair-climbing. We hypothesized that a concurrent cognitive task will have a greater impact on stair climbing performance compared to a concurrent motor task and that this impact will be greater on a higher-level step. Ten healthy young adults performed 10 trials of stair-climbing each under four conditions: stair ascending only, stair ascending and performing subtraction of serial sevens from a three-digit number, stair ascending and carrying an empty opaque box and stair ascending, performing subtraction of serial sevens from a random three-digit number and carrying an empty opaque box. Kinematics (lower extremity joint angles and minimum toe clearance) and kinetics (ground reaction forces and joint moments and powers) data were collected. We found that a concurrent cognitive task impacted kinetics but not kinematics of stair-climbing. The effect of dual-tasking during stair ascent also seemed to vary based on the different phases of stair ascent stance and seem to have greater impact as one climbs higher. Overall, the results of the current study suggest that the association between the executive functioning and motor task (like gait) becomes stronger as the level of complexity of the motor task increases. PMID:25773590

  9. Persistency and flexibility of complex brain networks underlie dual-task interference.

    Science.gov (United States)

    Alavash, Mohsen; Hilgetag, Claus C; Thiel, Christiane M; Gießing, Carsten

    2015-09-01

    Previous studies on multitasking suggest that performance decline during concurrent task processing arises from interfering brain modules. Here, we used graph-theoretical network analysis to define functional brain modules and relate the modular organization of complex brain networks to behavioral dual-task costs. Based on resting-state and task fMRI we explored two organizational aspects potentially associated with behavioral interference when human subjects performed a visuospatial and speech task simultaneously: the topological overlap between persistent single-task modules, and the flexibility of single-task modules in adaptation to the dual-task condition. Participants showed a significant decline in visuospatial accuracy in the dual-task compared with single visuospatial task. Global analysis of topological similarity between modules revealed that the overlap between single-task modules significantly correlated with the decline in visuospatial accuracy. Subjects with larger overlap between single-task modules showed higher behavioral interference. Furthermore, lower flexible reconfiguration of single-task modules in adaptation to the dual-task condition significantly correlated with larger decline in visuospatial accuracy. Subjects with lower modular flexibility showed higher behavioral interference. At the regional level, higher overlap between single-task modules and less modular flexibility in the somatomotor cortex positively correlated with the decline in visuospatial accuracy. Additionally, higher modular flexibility in cingulate and frontal control areas and lower flexibility in right-lateralized nodes comprising the middle occipital and superior temporal gyri supported dual-tasking. Our results suggest that persistency and flexibility of brain modules are important determinants of dual-task costs. We conclude that efficient dual-tasking benefits from a specific balance between flexibility and rigidity of functional brain modules. © 2015 Wiley

  10. Reaping the Benefits of Task Conflict in Teams: The Critical Role of Team Psychological Safety Climate

    Science.gov (United States)

    Bradley, Bret H.; Postlethwaite, Bennett E.; Klotz, Anthony C.; Hamdani, Maria R.; Brown, Kenneth G.

    2012-01-01

    Past research suggests that task conflict may improve team performance under certain conditions; however, we know little about these specific conditions. On the basis of prior theory and research on conflict in teams, we argue that a climate of psychological safety is one specific context under which task conflict will improve team performance.…

  11. Framing Effects: Dynamics and Task Domains

    Science.gov (United States)

    Wang

    1996-11-01

    The author examines the mechanisms and dynamics of framing effects in risky choices across three distinct task domains (i.e., life-death, public property, and personal money). The choice outcomes of the problems presented in each of the three task domains had a binary structure of a sure thing vs a gamble of equal expected value; the outcomes differed in their framing conditions and the expected values, raging from 6000, 600, 60, to 6, numerically. It was hypothesized that subjects would become more risk seeking, if the sure outcome was below their aspiration level (the minimum requirement). As predicted, more subjects preferred the gamble when facing the life-death choice problems than facing the counterpart problems presented in the other two task domains. Subjects' risk preference varied categorically along the group size dimension in the life-death domain but changed more linearly over the expected value dimension in the monetary domain. Framing effects were observed in 7 of 13 pairs of problems, showing a positive frame-risk aversion and negative frame-risk seeking relationship. In addition, two types of framing effects were theoretically defined and empirically identified. A bidirectional framing effect involves a reversal in risk preference, and occurs when a decision maker's risk preference is ambiguous or weak. Four bidirectional effects were observed; in each case a majority of subjects preferred the sure outcome under a positive frame but the gamble under a negative frame. In contrast, a unidirectional framing effect refers to a preference shift due to the framing of choice outcomes: A majority of subjects preferred one choice outcome (either the sure thing or the gamble) under both framing conditions, with positive frame augmented the preference for the sure thing and negative frame augmented the preference for the gamble. These findings revealed some dynamic regularities of framing effects and posed implications for developing predictive and testable

  12. Neuroticism influences pupillary responses during an emotional interference task.

    Science.gov (United States)

    Prehn, Kristin; Heekeren, Hauke R; Blasek, Katharina; Lapschies, Katharina; Mews, Isabella; van der Meer, Elke

    2008-10-01

    We used behavioral and pupillary measures during an analogical reasoning task to investigate the processing of conceptual and emotional relations as well as their interaction. In particular, we examined how mental resource consumption is modulated by individual differences in neuroticism in healthy participants during conditions with emotional interference. Two word pairs were presented simultaneously, each with a conceptual and an emotional relation. In one experimental block, participants had to decide whether conceptual relations between the two word pairs were corresponding (conceptual task). In the other block, participants had to decide whether emotional relations were corresponding (emotional task). When participants had to focus on the correspondence of emotional relations, they were faster, more accurate, and showed greater pupillary responses than during the conceptual task. Moreover, participants with comparably higher neuroticism scores showed increased pupillary responses during conditions with emotional interference (i.e., during the conceptual task when they had to ignore incongruent information on the correspondence provided by the task-irrelevant emotional relations). These results demonstrate that affective aspects of stimuli (here: emotional relations) are preferentially selected for information processing. Moreover, increased mental resource consumption due to emotional interference in participants with comparably higher neuroticism scores might reflect a possible mechanism making these individuals more vulnerable to mood or anxiety disorders.

  13. Multiple effects of prefrontal lesions on task-switching

    Directory of Open Access Journals (Sweden)

    Tim Shallice

    2008-03-01

    Full Text Available This study examined the performance of 41 patients with focal prefrontal cortical lesions and 38 healthy controls on a task-switching procedure. Three different conditions were evaluated: single tasks without switches and two switching tasks with the currently relevant task signalled either 1500 ms (Long Cue or 200 ms (Short Cue before the stimulus. Patients with Superior Medial lesions showed both a general slowing of reaction time (RT and a signifi cantly increased switch cost as measured by RT. No other prefrontal group showed this increased reaction time switch cost. Increased error rates in the switching conditions, on the other hand, were observed in patients with Inferior Medial lesions and, to a lesser extent, ones with Superior Medial lesions. Patients with left dorsolateral lesions (9/46v showed slower learning of the task as indicated by a high error rate early on. Several different processes are involved in task-switching and these are selectively disrupted by lesions to specifi c areas of the frontal lobes.

  14. Nicotine reduces antisaccade errors in task impaired schizophrenic subjects.

    Science.gov (United States)

    Larrison-Faucher, Abigail L; Matorin, Anu A; Sereno, Anne B

    2004-05-01

    Nicotine and/or smoking have been shown to reduce various cognitive deficits associated with schizophrenia. Here, we examine the effects of nicotine gum on repeated performance on a simple eye movement task. Eight schizophrenic subjects and eight controls participated in three days of testing on saccade (S) and antisaccade (AS) tasks. On each testing day, subjects participated in four testing sessions and received both of two nicotine gum treatments (4 and 6 mg) and both of two control conditions (placebo gum and no gum), each followed by a recovery period. Overall, schizophrenics showed significant impairments on the AS task. However, upon individual examination only four schizophrenics showed significant differences in AS errors or reaction times (RTs) when compared to controls. The other four schizophrenic subjects showed control level performance. All schizophrenic subjects showed normal and better than control level performance on the simple S task. Furthermore, no effects of nicotine were seen on the simple S task. There were significant treatment effects on the AS task. Nicotine treatment significantly decreased errors in the task impaired schizophrenic group and this effect was most pronounced at the 6 mg level. No nicotine effects were demonstrated for non-impaired schizophrenic subjects or controls. This study demonstrates a benefit of short exposure to nicotine in cognitively impaired schizophrenic subjects. These results support previous findings of cognitive benefits of nicotine in schizophrenics.

  15. Dual task and postural control in Alzheimer's and Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Larissa Pires de Andrade

    2014-03-01

    Full Text Available Patients with neurodegenerative diseases are required to use cognitive resources while maintaining postural control. The aim of this study was to investigate the effects of a frontal cognitive task on postural control in patients with Alzheimer, Parkinson and controls. Thirty-eight participants were instructed to stand upright on a force platform in two experimental conditions: single and dual task. Participants with Parkinson's disease presented an increase in the coefficient of variation greater than 100% in the dual task as compared to the single task for center of pressure (COP area and COP path. In addition, patients with Parkinson's and Alzheimer's disease had a higher number of errors during the execution of the cognitive task when compared to the group of elderly without neurodegenerative diseases. The motor cortex, which is engaged in postural control, does not seem to compete with frontal brain regions in the performance of the cognitive task. However, patients with Parkinson's and Alzheimer's disease presented worsened performance in cognitive task.

  16. The impact of task demand on visual word recognition.

    Science.gov (United States)

    Yang, J; Zevin, J

    2014-07-11

    The left occipitotemporal cortex has been found sensitive to the hierarchy of increasingly complex features in visually presented words, from individual letters to bigrams and morphemes. However, whether this sensitivity is a stable property of the brain regions engaged by word recognition is still unclear. To address the issue, the current study investigated whether different task demands modify this sensitivity. Participants viewed real English words and stimuli with hierarchical word-likeness while performing a lexical decision task (i.e., to decide whether each presented stimulus is a real word) and a symbol detection task. General linear model and independent component analysis indicated strong activation in the fronto-parietal and temporal regions during the two tasks. Furthermore, the bilateral inferior frontal gyrus and insula showed significant interaction effects between task demand and stimulus type in the pseudoword condition. The occipitotemporal cortex showed strong main effects for task demand and stimulus type, but no sensitivity to the hierarchical word-likeness was found. These results suggest that different task demands on semantic, phonological and orthographic processes can influence the involvement of the relevant regions during visual word recognition. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  17. The effect of cognitive aging on implicit sequence learning and dual tasking

    Directory of Open Access Journals (Sweden)

    Jochen eVandenbossche

    2014-02-01

    Full Text Available We investigated the influence of attentional demands on sequence-specific learning by means of the serial reaction time (SRT task (Nissen & Bullemer, 1987 in young (age 18-25 and aged (age 55-75 adults. Participants had to respond as fast as possible to a stimulus presented in one of four horizontal locations by pressing a key corresponding to the spatial position of the stimulus. During the training phase sequential blocks were accompanied by (1 no secondary task (single, (2 a secondary tone counting task (dual tone, or (3 a secondary shape counting task (dual shape. Both secondary tasks were administered to investigate whether low and high interference tasks interact with implicit learning and age. The testing phase, under baseline single condition, was implemented to assess differences in sequence-specific learning between young and aged adults. Results indicate that (1 aged subjects show less sequence learning compared to young adults, (2 young participants show similar implicit learning effects under both single and dual task conditions when we account for explicit awareness, and (3 aged adults demonstrate reduced learning when the primary task is accompanied with a secondary task, even when explicit awareness is included as a covariate in the analysis. These findings point to implicit learning deficits under dual task conditions that can be related to cognitive aging, demonstrating the need for sufficient cognitive resources while performing a sequence learning task.

  18. Specifying social cognitive processes with a social dual-task paradigm

    Directory of Open Access Journals (Sweden)

    Roman eLiepelt

    2012-04-01

    Full Text Available Automatic imitation tasks measuring motor priming effects showed that we directly map observed actions of other agents onto our own motor repertoire (direct matching. A recent joint-action study using a social dual-task paradigm provided evidence for task monitoring. In the present study, we aimed to test a if automatic imitation is disturbed during joint action and b if task monitoring is content or time dependent. We used a social dual task that was made of an automatic imitation task (Person 1: Task 1 and a two-choice number task (Person 2: Task 2. Each participant performed one of the two tasks, which were given with a variable stimulus onset asynchrony (SOA, in an individual and a joint condition. We found a regular motor priming effect in individual and joint conditions. Under joint conditions, we replicated the previous finding of an increase of reaction times for Person 2 with decreasing SOA. The latter effect was not related to the specific responses performed by both persons. Further, we did not find evidence for a representation of the other’s specific S-R mappings. Our findings suggest that a automatic imitation is not disturbed during joint action and b task monitoring is time dependent.

  19. Thalamocortical rhythms during a vibrotactile detection task.

    Science.gov (United States)

    Haegens, Saskia; Vázquez, Yuriria; Zainos, Antonio; Alvarez, Manuel; Jensen, Ole; Romo, Ranulfo

    2014-04-29

    To explore the role of oscillatory dynamics of the somatosensory thalamocortical network in perception and decision making, we recorded the simultaneous neuronal activity in the ventral posterolateral nucleus (VPL) of the somatosensory thalamus and primary somatosensory cortex (S1) in two macaque monkeys performing a vibrotactile detection task. Actively detecting a vibrotactile stimulus and reporting its perception elicited a sustained poststimulus beta power increase in VPL and an alpha power decrease in S1, in both stimulus-present and stimulus-absent trials. These oscillatory dynamics in the somatosensory thalamocortical network depended on the behavioral context: they were stronger for the active detection condition than for a passive stimulation condition. Furthermore, contrasting stimulus-present vs. stimulus-absent responses, we found that poststimulus theta power increased in both VPL and S1, and alpha/beta power decreased in S1, reflecting the monkey's perceptual decision but not the motor response per se. Additionally, higher prestimulus alpha power in S1 correlated with an increased probability of the monkey reporting a stimulus, regardless of the actual presence of a stimulus. Thus, we found task-related modulations in oscillatory activity, not only in the neocortex but also in the thalamus, depending on behavioral context. Furthermore, oscillatory modulations reflected the perceptual decision process and subsequent behavioral response. We conclude that these early sensory regions, in addition to their primary sensory functions, may be actively involved in perceptual decision making.

  20. Thalamocortical rhythms during a vibrotactile detection task

    Science.gov (United States)

    Haegens, Saskia; Vázquez, Yuriria; Zainos, Antonio; Alvarez, Manuel; Jensen, Ole; Romo, Ranulfo

    2014-01-01

    To explore the role of oscillatory dynamics of the somatosensory thalamocortical network in perception and decision making, we recorded the simultaneous neuronal activity in the ventral posterolateral nucleus (VPL) of the somatosensory thalamus and primary somatosensory cortex (S1) in two macaque monkeys performing a vibrotactile detection task. Actively detecting a vibrotactile stimulus and reporting its perception elicited a sustained poststimulus beta power increase in VPL and an alpha power decrease in S1, in both stimulus-present and stimulus-absent trials. These oscillatory dynamics in the somatosensory thalamocortical network depended on the behavioral context: they were stronger for the active detection condition than for a passive stimulation condition. Furthermore, contrasting stimulus-present vs. stimulus-absent responses, we found that poststimulus theta power increased in both VPL and S1, and alpha/beta power decreased in S1, reflecting the monkey’s perceptual decision but not the motor response per se. Additionally, higher prestimulus alpha power in S1 correlated with an increased probability of the monkey reporting a stimulus, regardless of the actual presence of a stimulus. Thus, we found task-related modulations in oscillatory activity, not only in the neocortex but also in the thalamus, depending on behavioral context. Furthermore, oscillatory modulations reflected the perceptual decision process and subsequent behavioral response. We conclude that these early sensory regions, in addition to their primary sensory functions, may be actively involved in perceptual decision making. PMID:24733899

  1. IEA Wind Task 36 Forecasting

    Science.gov (United States)

    Giebel, Gregor; Cline, Joel; Frank, Helmut; Shaw, Will; Pinson, Pierre; Hodge, Bri-Mathias; Kariniotakis, Georges; Sempreviva, Anna Maria; Draxl, Caroline

    2017-04-01

    Wind power forecasts have been used operatively for over 20 years. Despite this fact, there are still several possibilities to improve the forecasts, both from the weather prediction side and from the usage of the forecasts. The new International Energy Agency (IEA) Task on Wind Power Forecasting tries to organise international collaboration, among national weather centres with an interest and/or large projects on wind forecast improvements (NOAA, DWD, UK MetOffice, …) and operational forecaster and forecast users. The Task is divided in three work packages: Firstly, a collaboration on the improvement of the scientific basis for the wind predictions themselves. This includes numerical weather prediction model physics, but also widely distributed information on accessible datasets for verification. Secondly, we will be aiming at an international pre-standard (an IEA Recommended Practice) on benchmarking and comparing wind power forecasts, including probabilistic forecasts aiming at industry and forecasters alike. This WP will also organise benchmarks, in cooperation with the IEA Task WakeBench. Thirdly, we will be engaging end users aiming at dissemination of the best practice in the usage of wind power predictions, especially probabilistic ones. The Operating Agent is Gregor Giebel of DTU, Co-Operating Agent is Joel Cline of the US Department of Energy. Collaboration in the task is solicited from everyone interested in the forecasting business. We will collaborate with IEA Task 31 Wakebench, which developed the Windbench benchmarking platform, which this task will use for forecasting benchmarks. The task runs for three years, 2016-2018. Main deliverables are an up-to-date list of current projects and main project results, including datasets which can be used by researchers around the world to improve their own models, an IEA Recommended Practice on performance evaluation of probabilistic forecasts, a position paper regarding the use of probabilistic forecasts

  2. Number & operations task & drill sheets

    CERN Document Server

    Reed, Nat

    2011-01-01

    For grades 6-8, our State Standards-based combined resource meets the number & operations concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. The task sheets introduce the mathematical concepts to the students around a central problem taken from real-life experiences, while the drill sheets provide warm-up and timed practice questions for the students to strengthen their procedural proficiency skills. Included are problems involving place value, fractions, addition, subtraction and using money. The combined task & drill sheets offer spac

  3. The own-age face recognition bias is task dependent.

    Science.gov (United States)

    Proietti, Valentina; Macchi Cassia, Viola; Mondloch, Catherine J

    2015-08-01

    The own-age bias (OAB) in face recognition (more accurate recognition of own-age than other-age faces) is robust among young adults but not older adults. We investigated the OAB under two different task conditions. In Experiment 1 young and older adults (who reported more recent experience with own than other-age faces) completed a match-to-sample task with young and older adult faces; only young adults showed an OAB. In Experiment 2 young and older adults completed an identity detection task in which we manipulated the identity strength of target and distracter identities by morphing each face with an average face in 20% steps. Accuracy increased with identity strength and facial age influenced older adults' (but not younger adults') strategy, but there was no evidence of an OAB. Collectively, these results suggest that the OAB depends on task demands and may be absent when searching for one identity.

  4. Physical Activity Predicts Performance in an Unpracticed Bimanual Coordination Task

    Science.gov (United States)

    Boisgontier, Matthieu P.; Serbruyns, Leen; Swinnen, Stephan P.

    2017-01-01

    Practice of a given physical activity is known to improve the motor skills related to this activity. However, whether unrelated skills are also improved is still unclear. To test the impact of physical activity on an unpracticed motor task, 26 young adults completed the international physical activity questionnaire and performed a bimanual coordination task they had never practiced before. Results showed that higher total physical activity predicted higher performance in the bimanual task, controlling for multiple factors such as age, physical inactivity, music practice, and computer games practice. Linear mixed models allowed this effect of physical activity to be generalized to a large population of bimanual coordination conditions. This finding runs counter to the notion that generalized motor abilities do not exist and supports the existence of a “learning to learn” skill that could be improved through physical activity and that impacts performance in tasks that are not necessarily related to the practiced activity. PMID:28265253

  5. Cognitive impairments of aphasics in picture sorting and matching tasks.

    Science.gov (United States)

    Cohen, R; Glöckner-Rist, A; Lutz, M; Maier, T; Meier, E

    1982-01-01

    On the basis of earlier experiments showing a differential deficit of aphasics in picture sorting and matching tasks, two experiments were conducted to test the conjecture of a specific deficit of aphasics in the analytical appraisal of individual features. Broca's and Wernicke's aphasics--according to clinical diagnoses and the Aachener Aphasie Test--were compared with patients having right-hemisphere lesions or left-hemisphere lesions without aphasia. Both groups of aphasics differed from the control groups in the sorting task, irrespective of the sorting criterion, but the differences were small. The picture matching task did not discriminate between groups. Obviously, the basic assumption has to be modified with respect to specific conditions of task requirements. The experimental literature is reviewed.

  6. The task dependent interaction of the deactivation regions

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ye; FENG ShiGang; FENG HongBo; DONG Feng; TANG YiYuan

    2008-01-01

    Although deactivation has been found frequently in former functional brain imaging researches, only recently has it become a focus of systematic study because of its not well understood physiological mechanism. However, most of the researches concentrated on the brain areas that would present de-activation, and, to our knowledge, the deactivation connectivity between these brain areas during the cognitive tasks has rarely been reported in literature. In this work, using the functional connectivity method WlCA (within-condition interregional covariance analysis), we analyzed the deactivations in two different cognitive tasks-symbol orientation and number comparison. The results revealed de-activations in the posterior cingulate, precuneus, anterior cingulate and prefrontal cortex in both tasks. However, the interaction between the deactivated regions shows many differences. Our result further indicates that the potential implication of special deactivation connectivity may be related to the dif-ferent task or attention resource. Further research is needed to clarify the exact reason.

  7. Tendon vibration during submaximal isometric strength and postural tasks.

    Science.gov (United States)

    Spiliopoulou, S I; Amiridis, I G; Hatzitaki, V; Patikas, D; Kellis, E

    2012-11-01

    To establish the effect of tendon vibration (TV) on steady submaximal strength and static balance control, 29 women performed isometric plantarflexions at 10, 20, 30 and 50% of MVC and postural tasks of increasing difficulty (Normal Quiet Stance, NQS, Sharpened Tandem Stance and One Leg Stance) with vibrators (80 Hz) applied to the Achilles tendon. Both tasks were performed under four conditions (10 s each): eyes open, eyes closed, eyes closed with TV, eyes open with TV. During the isometric tasks, the application of TV increased the plantarflexion torque at 20 and 30% of MVC, accompanied by a greater (p vibration-induced muscle excitation and accompanying increase in motor output, probably due to excitatory Ia afferent input, was confirmed during strength and postural tasks. However, motor output attenuates when the magnitude of central drive to the ankle muscles increases.

  8. Preempting performance challenges: the effects of inoculation messaging on attacks to task self-efficacy.

    Science.gov (United States)

    Jackson, Ben; Compton, Josh; Whiddett, Ryan; Anthony, David R; Dimmock, James A

    2015-01-01

    Although inoculation messages have been shown to be effective for inducing resistance to counter-attitudinal attacks, researchers have devoted relatively little attention toward studying the way in which inoculation theory principles might support challenges to psychological phenomena other than attitudes (e.g., self-efficacy). Prior to completing a physical (i.e., balance) task, undergraduates (N = 127, Mage = 19.20, SD = 2.16) were randomly assigned to receive either a control or inoculation message, and reported their confidence in their ability regarding the upcoming task. During the task, a confederate provided standardized negative feedback to all participants regarding their performance, and following the completion of the task, participants again reported their self-efficacy along with measures assessing in-task processes. Findings supported the viability of efficacy inoculation; controlling for pre-task self-efficacy, task performance, and relevant psycho-social variables (e.g., resilience, self-confidence robustness), participants in the inoculation condition reported greater confidence in their ability (i.e., task self-efficacy) than those in the control condition at post-task. Relative to those in the inoculation condition, participants in the control condition also experienced greater concentration disruption and self-presentation concerns during the task.

  9. Perceptual grouping by similarity of surface roughness in haptics: the influence of task difficulty.

    Science.gov (United States)

    Van Aarsen, V; Overvliet, K E

    2016-08-01

    We investigated grouping by similarity of surface roughness in the context of task difficulty. We hypothesized that grouping yields a larger benefit at higher levels of task complexity, because efficient processing is more helpful when more cognitive resources are needed to execute a task. Participants searched for a patch of a different roughness as compared to the distractors in two strips of similar or dissimilar roughness values. We reasoned that if the distractors could be grouped based on similar roughness values, exploration time would be shorter and fewer errors would occur. To manipulate task complexity, we varied task difficulty (high target saliency equalling low task difficulty), and we varied the fingers used to explore the display (two fingers of one hand being more cognitive demanding than two fingers of opposite hands). We found much better performance in the easy condition as compared to the difficult condition (in both error rates and mean search slopes). Moreover, we found a larger effect for the similarity manipulation in the difficult condition as compared to the easy condition. Within the difficult condition, we found a larger effect for the one-hand condition as compared to the two-hand condition. These results show that haptic search is accelerated by the use of grouping by similarity of surface roughness, especially when the task is relatively complex. We conclude that the effect of perceptual grouping is more prominent when more cognitive resources are needed to perform a task.

  10. Hippocampal state-dependent behavioral reflex to an identical sensory input in rats.

    Directory of Open Access Journals (Sweden)

    Keita Tokuda

    Full Text Available We examined the local field potential of the hippocampus to monitor brain states during a conditional discrimination task, in order to elucidate the relationship between ongoing brain states and a conditioned motor reflex. Five 10-week-old Wistar/ST male rats underwent a serial feature positive conditional discrimination task in eyeblink conditioning using a preceding light stimulus as a conditional cue for reinforced trials. In this task, a 2-s light stimulus signaled that the following 350-ms tone (conditioned stimulus was reinforced with a co-terminating 100-ms periorbital electrical shock. The interval between the end of conditional cue and the onset of the conditioned stimulus was 4±1 s. The conditioned stimulus was not reinforced when the light was not presented. Animals successfully utilized the light stimulus as a conditional cue to drive differential responses to the identical conditioned stimulus. We found that presentation of the conditional cue elicited hippocampal theta oscillations, which persisted during the interval of conditional cue and the conditioned stimulus. Moreover, expression of the conditioned response to the tone (conditioned stimulus was correlated with the appearance of theta oscillations immediately before the conditioned stimulus. These data support hippocampal involvement in the network underlying a conditional discrimination task in eyeblink conditioning. They also suggest that the preceding hippocampal activity can determine information processing of the tone stimulus in the cerebellum and its associated circuits.

  11. Covert speech behavior during a silent language recitation task.

    Science.gov (United States)

    Livesay, J; Liebke, A; Samaras, M; Stanley, A

    1996-12-01

    This study tested the prediction that covert speech behavior measured electromyographically from the lips is significantly more prominent during a brief silent-language recitation task than a brief nonlanguage visualization task. Subjects were 20 right-handed, adult volunteers who agreed to participate. Subjects were tested in a multiple-baseline reversal design following an ABAB procedure whereby A1 and A2 were 30-sec. rest periods. B1 and B2 were alternatively assigned 30-sec. silent-language recitation and visualization test periods, respectively. Subjects' dorsal lips and nondominant forearm EMG measures were taken during resting baseline and testing conditions. In addition, subjects' skin surface temperature and heartrate were measured during the rest and test conditions. For the silent-language task, subjects were asked to recite 'mentally' the Pledge of Allegiance to the flag. Subjects were instructed to 'imagine seeing' the American flag for the visualization task. Subjects' mean lip EMG activity increased significantly from rest to the silent-language recitation task, while no significant change in mean lip EMG was observed from rest to the visualization condition.

  12. A Population of Assessment Tasks

    Science.gov (United States)

    Daro, Phil; Burkhardt, Hugh

    2012-01-01

    We propose the development of a "population" of high-quality assessment tasks that cover the performance goals set out in the "Common Core State Standards for Mathematics." The population will be published. Tests are drawn from this population as a structured random sample guided by a "balancing algorithm."

  13. Computer-Related Task Performance

    DEFF Research Database (Denmark)

    Longstreet, Phil; Xiao, Xiao; Sarker, Saonee

    2016-01-01

    The existing information system (IS) literature has acknowledged computer self-efficacy (CSE) as an important factor contributing to enhancements in computer-related task performance. However, the empirical results of CSE on performance have not always been consistent, and increasing an individua...

  14. A Population of Assessment Tasks

    Science.gov (United States)

    Daro, Phil; Burkhardt, Hugh

    2012-01-01

    We propose the development of a "population" of high-quality assessment tasks that cover the performance goals set out in the "Common Core State Standards for Mathematics." The population will be published. Tests are drawn from this population as a structured random sample guided by a "balancing algorithm."

  15. Use cases versus task descriptions

    DEFF Research Database (Denmark)

    Lauesen, Søren; Kuhail, Mohammad Amin

    2011-01-01

    to specify require-ments for the same project: Acquire a new system to support a hotline. [Princi-pal ideas/results] Among the 15 replies, eight used traditional use cases that specified a dialog between users and system. Seven used a related technique, task description, which specified the customer's needs...

  16. Task-Based Writing Instruction

    Science.gov (United States)

    Bantis, Alexandros

    2010-01-01

    The purpose of this study was to investigate the impact of task-based writing instruction, a communicative language-teaching method, on second language acquisition and differentiation of instruction for English language learners during the independent work time instructional component of the Open Court Reading program. Through student-teacher…

  17. On the Tasks of Translation

    Institute of Scientific and Technical Information of China (English)

    王晓菊

    2012-01-01

      Many linguists, translators, and theorists have been arguing over the approaches on translation. While putting these into use a translator may experience many pleasure and problems as well. The purpose of this article is to discuss the tasks of translation and the way of choosing the proper translation approaches according to the author’s own experience of practice.

  18. Dual-Task Interference: The Effects of Verbal Cognitive Tasks on Upright Postural Stability in Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    J. D. Holmes

    2010-01-01

    Full Text Available Although dual-task interference has previously been demonstrated to have a significant effect on postural control among individuals with Parkinson's disease, the impact of speech complexity on postural control has not been demonstrated using quantitative biomechanical measures. The postural stability of twelve participants with idiopathic Parkinson's disease and twelve healthy age-matched controls was evaluated under three conditions: (1 without a secondary task, (2 performing a rote repetition task and (3 generating a monologue. Results suggested a significant effect of cognitive load on biomechanical parameters of postural stability. Although both groups increased their postural excursion, individuals with Parkinson's disease demonstrated significantly reduced excursion as compared with that of healthy age-matched controls. This suggests that participants with Parkinson's disease may be overconstraining their postural adjustments in order to focus attention on the cognitive tasks without losing their balance. Ironically, this overconstraint may place the participant at greater risk for a fall.

  19. Disruption of bradycardia associated with discriminative conditioning in combat veterans with PTSD

    Directory of Open Access Journals (Sweden)

    Jay P Ginsberg

    2008-06-01

    Full Text Available Jay P Ginsberg1,2, Edwin Ayers3, Louisa Burriss1, Donald A Powell1,41Shirley L. Buchanan Neuroscience Laboratory, Dorn VA Medical Center, Columbia, SC, USA; 2Department of Pharmacology, Physiology, and Neuroscience, School of Medicine, 4Department of Psychology, University of South Carolina, Columbia, SC, USA; 3Department of Psychology, South Carolina State University, Orangeburg, SC, USAAbstract: The effects of combat-related posttraumatic stress disorder (PTSD on heart rate (HR responding associated with a discriminative delay eyeblink (EB conditioning paradigm are reported. Combat PTSD+, Combat PTSD−, and Noncombat PTSD− veterans were assessed with psychometric self-report measures, and baseline heart rate variability (HRV was measured before receiving a 72-trial session of discriminative EB classical conditioning. Two types (red or green light of conditioned stimuli (CS were used: one (CS+ predicted a tone, followed immediately by an aversive stimulus (corneal airpuff; the other (CS− predicted a tone alone, not followed by the airpuff. The light signal was presented for 5 seconds, during which HR was measured. On all psychometric measures, the PTSD+ subgroup was significantly different from the PTSD− subgroups (Combat + Noncombat, and the PTSD− subgroups did not significantly differ from each other. A linear deceleration in HR to CS+ and CS− signals was found in the combined PTSD− subgroup and on CS− trials in the PTSD+ subgroup, but was not present on CS+ trials in the PTSD+ subgroup. Results are interpreted with respect to a behavioral stages model of conditioned bradycardia and in terms of neural substrates which are both critical to HR conditioning and known to be abnormal in PTSD.Keywords: bradycardia, PTSD, combat veterans, classical conditioning

  20. Luminance controlled pupil size affects Landolt C task performance. Revision

    Energy Technology Data Exchange (ETDEWEB)

    Berman, S.M. [Lawrence Berkeley Lab., CA (United States); Fein, G. [Neurobehavioral Lab. Software, San Rafael, CA (United States); Jewett, D.L.; Ashford, F. [ABRATech Corp., Mill Valley, CA (United States)

    1993-02-01

    Subjects judged the orientation of a 2 min. gap Landolt C located at a distance of 2.4 m. The stimuli were presented in central vision on a CRT, at low to medium contrast. The effects of varying the spectrum and luminance of surround lighting were assessed on both pupil size (measured using infrared pupillometry during task performance) and task accuracy. The task display was protected from the surround lighting, so that its luminance and contrast could be varied independently of the changes in the surround lighting. Indirect surround illumination was provided by either two illuminants of very different scotopic spectral content but with the same photopic luminance (Experiments 1 and 3), or by using the same illuminant at two different luminance levels (Experiment 2). In Experiment 3, the effect of changing surround spectrum was compared to the effect of varying task background luminance between 12 cd/m{sup 2} and 73 cd/m{sup 2}. In all experiments, scotopically enhanced surround lighting produced pupil areas which were reduced by almost 50% in comparison with surround lighting with relatively less scotopic luminance. Concomitantly there was improvement in Landolt C task performance with the scotopically enhanced surround lighting at all contrast and luminance levels. In these experiments, smaller pupil sizes were associated with significantly better visual-task performance in spite of lower task retinal illuminance when compared to the condition with larger pupils. These results suggest that changes in surround spectrum can compensate for the effect on task performance of a reduction in task luminance and supports the hypothesis that lighting energy savings could accrue in the workplace by shifting lamp spectra to obtain greater scotopic efficacy.

  1. Luminance controlled pupil size affects Landolt C task performance

    Energy Technology Data Exchange (ETDEWEB)

    Berman, S.M. (Lawrence Berkeley Lab., CA (United States)); Fein, G. (Neurobehavioral Lab. Software, San Rafael, CA (United States)); Jewett, D.L.; Ashford, F. (ABRATech Corp., Mill Valley, CA (United States))

    1993-02-01

    Subjects judged the orientation of a 2 min. gap Landolt C located at a distance of 2.4 m. The stimuli were presented in central vision on a CRT, at low to medium contrast. The effects of varying the spectrum and luminance of surround lighting were assessed on both pupil size (measured using infrared pupillometry during task performance) and task accuracy. The task display was protected from the surround lighting, so that its luminance and contrast could be varied independently of the changes in the surround lighting. Indirect surround illumination was provided by either two illuminants of very different scotopic spectral content but with the same photopic luminance (Experiments 1 and 3), or by using the same illuminant at two different luminance levels (Experiment 2). In Experiment 3, the effect of changing surround spectrum was compared to the effect of varying task background luminance between 12 cd/m[sup 2] and 73 cd/m[sup 2]. In all experiments, scotopically enhanced surround lighting produced pupil areas which were reduced by almost 50% in comparison with surround lighting with relatively less scotopic luminance. Concomitantly there was improvement in Landolt C task performance with the scotopically enhanced surround lighting at all contrast and luminance levels. In these experiments, smaller pupil sizes were associated with significantly better visual-task performance in spite of lower task retinal illuminance when compared to the condition with larger pupils. These results suggest that changes in surround spectrum can compensate for the effect on task performance of a reduction in task luminance and supports the hypothesis that lighting energy savings could accrue in the workplace by shifting lamp spectra to obtain greater scotopic efficacy.

  2. Environmental Conditions in Kentucky's Penal Institutions

    Science.gov (United States)

    Bell, Irving

    1974-01-01

    A state task force was organized to identify health or environmental deficiencies existing in Kentucky penal institutions. Based on information gained through direct observation and inmate questionnaires, the task force concluded that many hazardous and unsanitary conditions existed, and recommended that immediate action be given to these…

  3. Persuading and Dissuading by Conditional Argument

    Science.gov (United States)

    Thompson, V.A.; Evans, J.St.B.T.; Handley, S.J.

    2005-01-01

    Informal reasoning typically draws on a wider range of inferential behaviour than is measured by traditional inference tasks. In this paper, we developed several tasks to study informal reasoning with two novel types of conditional statements: Persuasions (e.g., if the Kyoto accord is ratified, greenhouse gas emissions will be reduced) and…

  4. Effect of Water Immersion on Dual-task Performance: Implications for Aquatic Therapy.

    Science.gov (United States)

    Schaefer, Sydney Y; Louder, Talin J; Foster, Shayla; Bressel, Eadric

    2016-09-01

    Much is known about cardiovascular and biomechanical responses to exercise during water immersion, yet an understanding of the higher-order neural responses to water immersion is unclear. The purpose of this study was to compare cognitive and motor performance between land and water environments using a dual-task paradigm, which served as an indirect measure of cortical processing. A quasi-experimental crossover research design is used. Twenty-two healthy participants (age = 24.3 ± 5.24 years) and a single-case patient (age = 73) with mild cognitive impairment performed a cognitive (auditory vigilance) and motor (standing balance) task separately (single-task condition) and simultaneously (dual-task condition) on land and in chest-deep water. Listening errors from the auditory vigilance task and centre of pressure (CoP) area for the balance task measured cognitive and motor performance, respectively. Listening errors for the single-task and dual-task conditions were 42% and 45% lower for the water than land condition, respectively (effect size [ES] = 0.38 and 0.55). CoP area for the single-task and dual-task conditions, however, were 115% and 164% lower on land than in water, respectively, and were lower (≈8-33%) when balancing concurrently with the auditory vigilance task compared with balancing alone, regardless of environment (ES = 0.23-1.7). This trend was consistent for the single-case patient. Participants tended to make fewer 'cognitive' errors while immersed chest-deep in water than on land. These same participants also tended to display less postural sway under dual-task conditions, but more in water than on land. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  5. Who multi-tasks and why? Multi-tasking ability, perceived multi-tasking ability, impulsivity, and sensation seeking.

    Directory of Open Access Journals (Sweden)

    David M Sanbonmatsu

    Full Text Available The present study examined the relationship between personality and individual differences in multi-tasking ability. Participants enrolled at the University of Utah completed measures of multi-tasking activity, perceived multi-tasking ability, impulsivity, and sensation seeking. In addition, they performed the Operation Span in order to assess their executive control and actual multi-tasking ability. The findings indicate that the persons who are most capable of multi-tasking effectively are not the persons who are most likely to engage in multiple tasks simultaneously. To the contrary, multi-tasking activity as measured by the Media Multitasking Inventory and self-reported cell phone usage while driving were negatively correlated with actual multi-tasking ability. Multi-tasking was positively correlated with participants' perceived ability to multi-task ability which was found to be significantly inflated. Participants with a strong approach orientation and a weak avoidance orientation--high levels of impulsivity and sensation seeking--reported greater multi-tasking behavior. Finally, the findings suggest that people often engage in multi-tasking because they are less able to block out distractions and focus on a singular task. Participants with less executive control--low scorers on the Operation Span task and persons high in impulsivity--tended to report higher levels of multi-tasking activity.

  6. The Importance of Context in Task Selection

    Science.gov (United States)

    Weiland, Travis

    2017-01-01

    Context is at the core of any statistical investigation, yet many statistics tasks barely require students to go beyond superficial consideration of the contexts the tasks are situated in. In this article, I discuss a framework for evaluating the level of interaction with context a task requires of students and how to modify tasks to increase the…

  7. Tasks for Easily Modifiable Virtual Environments

    Science.gov (United States)

    Swier, Robert

    2014-01-01

    Recent studies of learner interaction in virtual worlds have tended to select basic tasks involving open-ended communication. There is evidence that such tasks are supportive of language acquisition, however it may also be beneficial to consider more complex tasks. Research in task-based learning has identified features such as non-linguistic…

  8. Cosmetology: Task Analyses. Competency-Based Education.

    Science.gov (United States)

    Henrico County Public Schools, Glen Allen, VA. Virginia Vocational Curriculum Center.

    These task analyses are designed to be used in combination with the "Trade and Industrial Education Service Area Resource" in order to implement competency-based education in the cosmetology program in Virginia. The task analysis document contains the task inventory, suggested task sequence lists, and content outlines for the secondary…

  9. The Importance of Context in Task Selection

    Science.gov (United States)

    Weiland, Travis

    2017-01-01

    Context is at the core of any statistical investigation, yet many statistics tasks barely require students to go beyond superficial consideration of the contexts the tasks are situated in. In this article, I discuss a framework for evaluating the level of interaction with context a task requires of students and how to modify tasks to increase the…

  10. Comparison of Functional Connectivity Estimated from Concatenated Task-State Data from Block-Design Paradigm with That of Continuous Task

    Science.gov (United States)

    Zhu, Yang; Cheng, Lin; He, Naying; Yang, Yang; Ling, Huawei; Tong, Shanbao

    2017-01-01

    Functional connectivity (FC) analysis with data collected as continuous tasks and activation analysis using data from block-design paradigms are two main methods to investigate the task-induced brain activation. If the concatenated data of task blocks extracted from the block-design paradigm could provide equivalent FC information to that derived from continuous task data, it would shorten the data collection time and simplify experimental procedures, and the already collected data of block-design paradigms could be reanalyzed from the perspective of FC. Despite being used in many studies, such a hypothesis of equivalence has not yet been tested from multiple perspectives. In this study, we collected fMRI blood-oxygen-level-dependent signals from 24 healthy subjects during a continuous task session as well as in block-design task sessions. We compared concatenated task blocks and continuous task data in terms of region of interest- (ROI-) based FC, seed-based FC, and brain network topology during a short motor task. According to our results, the concatenated data was not significantly different from the continuous data in multiple aspects, indicating the potential of using concatenated data to estimate task-state FC in short motor tasks. However, even under appropriate experimental conditions, the interpretation of FC results based on concatenated data should be cautious and take the influence due to inherent information loss during concatenation into account. PMID:28191030

  11. Complementary coordination strategies in a joint Fitts’ reciprocal aiming task

    DEFF Research Database (Denmark)

    Konvalinka, Ivana; Skewes, Lea; Michael, J.

    in conditions where they either received auditory feedback of 1) SELF-generated taps, 2) taps generated by the OTHER co-actor, or 3) regular, COMPUTER-generated taps. In conditions 2) and 3), they were also instructed to synchronize with their feedback as best as possible. In each trial, each participant...... was assigned to either the target’s role – with varying target width, and hence task difficulty – or the reference role – with the widest (easiest) target. Results show that when the task was performed interactively with the other person, they were most synchronized, and also used the target most similarly......, while compromising rhythmic accuracy. In addition, as task difficulty increased for the member with the target’s role, the participant with the reference role became more adaptive to her tempo. This suggests that interacting members of a dyad optimally negotiate coordination strategies to achieve...

  12. Task allocation in a distributed computing system

    Science.gov (United States)

    Seward, Walter D.

    1987-01-01

    A conceptual framework is examined for task allocation in distributed systems. Application and computing system parameters critical to task allocation decision processes are discussed. Task allocation techniques are addressed which focus on achieving a balance in the load distribution among the system's processors. Equalization of computing load among the processing elements is the goal. Examples of system performance are presented for specific applications. Both static and dynamic allocation of tasks are considered and system performance is evaluated using different task allocation methodologies.

  13. Individual Differences in Secondary Task Performance.

    Science.gov (United States)

    1980-09-01

    task similar to that used by Atkinson and Shiffrin (1968). The spatial task in- volved holding in memory a random pattern of plus signs. In all cases...may serve to attenuate the easy-to-hard correlation. I *1,~ __ __ _ Secondary Task Performance 33 References Atkinson , R. C., & Shiffrin , R. M. Human...aIde if nec.eaar, and Identify by block number) ability, attention, dual task, information processing, individual differences memory , secondary task

  14. Research on Geographical Urban Conditions Monitoring

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    by LUO A1inghai Abstract Geographical national conditions monitoring has become an important task of surveying and geographical information industry, and will make a profound influence on the development of surveying and ge- ographical information. This paper introduced the basic concept of ge- ographical national conditions monitoring, and discussed its main tasks including complete surveying, dynamic monitoring, statistical analysis and regular release, and expounded the main content of geographical urban conditions monitoring including urbanization monitoring, social- economic development monitoring, transportation foundation monitor- ing and natural ecological environment monitoring, and put forwards the framework system of geographical urban conditions monitoring. Key words surveying and mapping ,geographical national conditions, monitoring ( Page:l )

  15. Stroop proactive control and task conflict are modulated by concurrent working memory load.

    Science.gov (United States)

    Kalanthroff, Eyal; Avnit, Amir; Henik, Avishai; Davelaar, Eddy J; Usher, Marius

    2015-06-01

    Performance on the Stroop task reflects two types of conflict-informational (between the incongruent word and font color) and task (between the contextually relevant color-naming task and the irrelevant, but automatic, word-reading task). According to the dual mechanisms of control theory (DMC; Braver, 2012), variability in Stroop performance can result from variability in the deployment of a proactive task-demand control mechanism. Previous research has shown that when proactive control (PC) is diminished, both increased Stroop interference and a reversed Stroop facilitation (RF) are observed. Although the current DMC model accounts for the former effect, it does not predict the observed RF, which is considered to be behavioral evidence for task conflict in the Stroop task. Here we expanded the DMC model to account for Stroop RF. Assuming that a concurrent working memory (WM) task reduces PC, we predicted both increased interference and an RF. Nineteen participants performed a standard Stroop task combined with a concurrent n-back task, which was aimed at reducing available WM resources, and thus overloading PC. Although the results indicated common Stroop interference and facilitation in the low-load condition (zero-back), in the high-load condition (two-back), both increased Stroop interference and RF were observed, consistent with the model's prediction. These findings indicate that PC is modulated by concurrent WM load and serves as a common control mechanism for both informational and task Stroop conflicts.

  16. Enhancing Automaticity through Task-Based Language Learning

    Science.gov (United States)

    De Ridder, Isabelle; Vangehuchten, Lieve; Gomez, Marta Sesena

    2007-01-01

    In general terms automaticity could be defined as the subconscious condition wherein "we perform a complex series of tasks very quickly and efficiently, without having to think about the various components and subcomponents of action involved" (DeKeyser 2001: 125). For language learning, Segalowitz (2003) characterised automaticity as a…

  17. Enhancing Automaticity through Task-Based Language Learning

    Science.gov (United States)

    De Ridder, Isabelle; Vangehuchten, Lieve; Gomez, Marta Sesena

    2007-01-01

    In general terms automaticity could be defined as the subconscious condition wherein "we perform a complex series of tasks very quickly and efficiently, without having to think about the various components and subcomponents of action involved" (DeKeyser 2001: 125). For language learning, Segalowitz (2003) characterised automaticity as a…

  18. Preservice Teachers' Learning to Plan Intellectually Challenging Tasks

    Science.gov (United States)

    Kang, Hosun

    2017-01-01

    This study explores how and under which conditions preservice secondary science teachers (PSTs) engage in effective planning practices that incorporate intellectually challenging tasks into lessons. Drawing upon a situative perspective on learning, eight PSTs' trajectories of participation in communities of practice are examined with a focus on…

  19. University Pedagogical Education under Today's Conditions

    Science.gov (United States)

    Sergeev, N. K.

    2013-01-01

    The task of making teacher education more suited to the prevailing conditions in Russian society requires both a rethinking of the goals and curriculums of programs, and better coordination of activities across the spectrum of educational institutions.

  20. mSpace Mobile: Exploring Support for Mobile Tasks

    OpenAIRE

    Wilson, Max L.; Russell, Alistair; Smith, Daniel A.; Schraefel, M. C.

    2006-01-01

    In the following paper we present a formative study comparing two Web application interfaces, mSpace Mobile and Google Local in supporting Web-based location discovery tasks on mobile devices while stationary and while on the move. While mSpace Mobile performed well in both stationary and mobile conditions, performance in Google Local dropped significantly in the mobile condition. We postulate that mSpace Mobile performed better because it breaks the paradigm of the page for delivering Web co...

  1. Novel Peritonsillar Abscess Task Simulator.

    Science.gov (United States)

    Taylor, Steven R; Chang, C W David

    2014-07-01

    The management of peritonsillar abscesses is a skill developed early in residency training. Although drainage is not technically complicated, the procedure is intimidating to the neophyte. Task simulators have become increasingly common to provide training opportunities in a controlled environment. The authors designed a peritonsillar abscess simulator using a latex moulage of the oral cavity and other common materials. Twelve medical professionals of various levels of experience were instructed to expose, anesthetize, aspirate, and drain the simulated abscess. After completion, a questionnaire was completed by each volunteer. Initial impressions were positive that the model adequately replicated the tasks requisite for abscess drainage and was suitable as an instructional device. The initial construct cost was approximately 10 dollars, with disposables costing roughly 25 cents. Further research is under way to formally assess the simulator for face, content, and construct validity.

  2. Discrepancy of neural response between exogenous and endogenous task switching: an event-related potentials study.

    Science.gov (United States)

    Miyajima, Maki; Toyomaki, Atsuhito; Hashimoto, Naoki; Kusumi, Ichiro; Murohashi, Harumitsu; Koyama, Tsukasa

    2012-08-01

    Task switching is a well-known cognitive paradigm to explore task-set reconfiguration processes such as rule shifting. In particular, endogenous task switching is thought to differ qualitatively from stimulus-triggered exogenous task switching. However, no previous study has examined the neural substrate of endogenous task switching. The purpose of the present study is to explore the differences between event-related potential responses to exogenous and endogenous rule switching at cue stimulus. We modified two patterns of cued switching tasks: exogenous (bottom-up) rule switching and endogenous (top-down) rule switching. In each task cue stimulus was configured to induce switching or maintaining rule. In exogenous switching tasks, late positive deflection was larger in the switch rule condition than in the maintain rule condition. However, in endogenous switching tasks late positive deflection was unexpectedly larger in the maintain-rule condition than in the switch-rule condition. These results indicate that exogenous rule switching is explicit stimulus-driven processes, whereas endogenous rule switching is implicitly parallel processes independent of external stimulus.

  3. Probabilistic analysis of manipulation tasks: A conceptual framework

    Energy Technology Data Exchange (ETDEWEB)

    Brost, R.C. [Sandia National Lab., Albuquerque, NM (United States); Christiansen, A.D. [Tulane Univ., New Orleans, LA (United States)

    1996-02-01

    This article addresses the problem of manipulation planning in the presence of uncertainty. We begin by reviewing the worst-case planning techniques introduced by Lozano-Perez et al. (1984) and show that these methods are limited by an information gap inherent to worst-case analysis techniques. As the task uncertainty increases, these methods fail to produce useful information, even though a high-quality plan may exist. To fill this gap, we present the notion of a probabilistic back-projection, which describes the likelihood that a given action will achieve the task goal from a given initial state. We provide a constructive definition of the probabilistic backprojection and related probabilistic models of munipulation task mechanics and show how these models unify and enhance several past results in manipulation planning. These models capture the fundamental nature of the task behavior but appear to be very complex. We present the results of laboratory experiments, comprising over 100,000 grasping trials, that measured the probabilistic backprojection of a grasping task under varying conditions. The resulting data support the probabilistic backprojection model and illustrate a task in which probabilistic analysis is required. We sketch methods for computing these models and using them to construct multiple-step plans. 25 refs., 20 figs.

  4. Force-field compensation in a manual tracking task.

    Directory of Open Access Journals (Sweden)

    Valentina Squeri

    Full Text Available This study addresses force/movement control in a dynamic "hybrid" task: the master sub-task is continuous manual tracking of a target moving along an eight-shaped Lissajous figure, with the tracking error as the primary performance index; the slave sub-task is compensation of a disturbing curl viscous field, compatibly with the primary performance index. The two sub-tasks are correlated because the lateral force the subject must exert on the eight-shape must be proportional to the longitudinal movement speed in order to perform a good tracking. The results confirm that visuo-manual tracking is characterized by an intermittent control mechanism, in agreement with previous work; the novel finding is that the overall control patterns are not altered by the presence of a large deviating force field, if compared with the undisturbed condition. It is also found that the control of interaction-forces is achieved by a combination of arm stiffness properties and direct force control, as suggested by the systematic lateral deviation of the trajectories from the nominal path and the comparison between perturbed trials and catch trials. The coordination of the two sub-tasks is quickly learnt after the activation of the deviating force field and is achieved by a combination of force and the stiffness components (about 80% vs. 20%, which is a function of the implicit accuracy of the tracking task.

  5. Reward Motivation Enhances Task Coding in Frontoparietal Cortex.

    Science.gov (United States)

    Etzel, Joset A; Cole, Michael W; Zacks, Jeffrey M; Kay, Kendrick N; Braver, Todd S

    2016-04-01

    Reward motivation often enhances task performance, but the neural mechanisms underlying such cognitive enhancement remain unclear. Here, we used a multivariate pattern analysis (MVPA) approach to test the hypothesis that motivation-related enhancement of cognitive control results from improved encoding and representation of task set information. Participants underwent two fMRI sessions of cued task switching, the first under baseline conditions, and the second with randomly intermixed reward incentive and no-incentive trials. Information about the upcoming task could be successfully decoded from cue-related activation patterns in a set of frontoparietal regions typically associated with task control. More critically, MVPA classifiers trained on the baseline session had significantly higher decoding accuracy on incentive than non-incentive trials, with decoding improvement mediating reward-related enhancement of behavioral performance. These results strongly support the hypothesis that reward motivation enhances cognitive control, by improving the discriminability of task-relevant information coded and maintained in frontoparietal brain regions. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  6. Supervisory control of multiple robots in dynamic tasking environments.

    Science.gov (United States)

    Chen, Jessie Y C; Barnes, Michael J

    2012-01-01

    A military targeting environment was simulated to examine the effects of an intelligent route-planning agent RoboLeader, which could support dynamic robot re-tasking based on battlefield developments, on the performance of robotics operators. We manipulated the level of assistance (LOAs) provided by RoboLeader as well as the presence of a visualisation tool that provided feedback to the participants on their primary task (target encapsulation) performance. Results showed that the participants' primary task benefited from RoboLeader on all LOAs conditions compared to manual performance; however, visualisation had little effect. Frequent video gamers demonstrated significantly better situation awareness of the mission environment than did infrequent gamers. Those participants with higher spatial ability performed better on a secondary target detection task than did those with lower spatial ability. Finally, participants' workload assessments were significantly lower when they were assisted by RoboLeader than when they performed the target entrapment task manually. Practitioner Summary: This study demonstrated the utility of an intelligent agent for enhancing robotics operators' supervisory control performance as well as reducing their workload during a complex urban scenario involving moving targets. The results furthered the understanding of the interplay among level-of-autonomy, multitasking performance and individual differences in military tasking environments.

  7. Asynchronous Task-Based Polar Decomposition on Manycore Architectures

    KAUST Repository

    Sukkari, Dalal

    2016-10-25

    This paper introduces the first asynchronous, task-based implementation of the polar decomposition on manycore architectures. Based on a new formulation of the iterative QR dynamically-weighted Halley algorithm (QDWH) for the calculation of the polar decomposition, the proposed implementation replaces the original and hostile LU factorization for the condition number estimator by the more adequate QR factorization to enable software portability across various architectures. Relying on fine-grained computations, the novel task-based implementation is also capable of taking advantage of the identity structure of the matrix involved during the QDWH iterations, which decreases the overall algorithmic complexity. Furthermore, the artifactual synchronization points have been severely weakened compared to previous implementations, unveiling look-ahead opportunities for better hardware occupancy. The overall QDWH-based polar decomposition can then be represented as a directed acyclic graph (DAG), where nodes represent computational tasks and edges define the inter-task data dependencies. The StarPU dynamic runtime system is employed to traverse the DAG, to track the various data dependencies and to asynchronously schedule the computational tasks on the underlying hardware resources, resulting in an out-of-order task scheduling. Benchmarking experiments show significant improvements against existing state-of-the-art high performance implementations (i.e., Intel MKL and Elemental) for the polar decomposition on latest shared-memory vendors\\' systems (i.e., Intel Haswell/Broadwell/Knights Landing, NVIDIA K80/P100 GPUs and IBM Power8), while maintaining high numerical accuracy.

  8. Fuel oil quality task force

    Energy Technology Data Exchange (ETDEWEB)

    Laisy, J.; Turk, V. [R.W. Beckett Corp., Elyria, OH (United States)

    1997-09-01

    In April, 1996, the R.W. Beckett Corporation became aware of a series of apparently unrelated symptoms that made the leadership of the company concerned that there could be a fuel oil quality problem. A task force of company employees and industry consultants was convened to address the topic of current No. 2 heating oil quality and its effect on burner performance. The task force studied changes in fuel oil specifications and trends in properties that have occurred over the past few years. Experiments were performed at Beckett and Brookhaven National Laboratory to understand the effect of changes in some fuel oil properties. Studies by other groups were reviewed, and field installations were inspected to gain information about the performance of fuel oil that is currently being used in the U.S. and Canada. There was a special concern about the use of red dye in heating oils and the impact of sulfur levels due to the October, 1993 requirement of low sulfur (<0.05%) for on-highway diesel fuel. The results of the task force`s efforts were published in July, 1996. The primary conclusion of the task force was that there is not a crisis or widespread general problem with fuel oil quality. Localized problems that were seen may have been related to refinery practices and/or non-traditional fuel sources. System cleanliness is very important and the cause of many oil burner system problems. Finally, heating oil quality should get ongoing careful attention by Beckett engineering personnel and heating oil industry groups.

  9. Measuring Multi-tasking Ability

    Science.gov (United States)

    2003-07-01

    research. Table 2. Candidate MT Jobs Emergency Room Nurse Emergency Medical Technician Emergency Room Physician Intensive Care Nurse Floor Nurse Waitress ...the ICU and floor nurses, chefs, Army combat leaders, LCAC Craftmasters and LCAC Navigators who educated us about multi- tasking in the working world...different for intensive care nurses than for floor nurses. Hence, individuals were interviewed who had performed a variety of food preparation

  10. Following the time course of face gender and expression processing: a task-dependent ERP study.

    Science.gov (United States)

    Valdés-Conroy, Berenice; Aguado, Luis; Fernández-Cahill, María; Romero-Ferreiro, Verónica; Diéguez-Risco, Teresa

    2014-05-01

    The effects of task demands and the interaction between gender and expression in face perception were studied using event-related potentials (ERPs). Participants performed three different tasks with male and female faces that were emotionally inexpressive or that showed happy or angry expressions. In two of the tasks (gender and expression categorization) facial properties were task-relevant while in a third task (symbol discrimination) facial information was irrelevant. Effects of expression were observed on the visual P100 component under all task conditions, suggesting the operation of an automatic process that is not influenced by task demands. The earliest interaction between expression and gender was observed later in the face-sensitive N170 component. This component showed differential modulations by specific combinations of gender and expression (e.g., angry male vs. angry female faces). Main effects of expression and task were observed in a later occipito-temporal component peaking around 230 ms post-stimulus onset (EPN or early posterior negativity). Less positive amplitudes in the presence of angry faces and during performance of the gender and expression tasks were observed. Finally, task demands also modulated a positive component peaking around 400 ms (LPC, or late positive complex) that showed enhanced amplitude for the gender task. The pattern of results obtained here adds new evidence about the sequence of operations involved in face processing and the interaction of facial properties (gender and expression) in response to different task demands. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Responding by exclusion in temporal discrimination tasks.

    Science.gov (United States)

    Cippola, Nathália Sabaine; Domeniconi, Camila; Machado, Armando

    2014-03-01

    Responding by exclusion, one of the most robust phenomena in Experimental Psychology, describes a particular form of responding observed in symbolic, matching-to-sample tasks. Given two comparison stimuli, one experimentally defined and one experimentally undefined, the participant prefers the undefined comparison following an undefined sample. The goal of the present study was to determine whether responding by exclusion could be obtained using samples that varied along a single dimension. Using a double temporal bisection task, 10 university students learned to choose visual comparisons (colored circles) based on the duration of a tone. In tests of exclusion, sample stimuli with new durations were followed by comparison sets that included one previously trained, defined comparison (colored circle) and one previously untrained, undefined comparison (geometric shape). Participants preferred the defined comparisons following the defined samples and the undefined comparisons following the undefined samples, the choice pattern typical of responding by exclusion. The use of samples varying along a single dimension allows us to study the interaction between stimulus generalization gradients and exclusion in the control of conditional responding.

  12. Situation awareness and driving performance in a simulated navigation task.

    Science.gov (United States)

    Ma, R; Kaber, D B

    2007-08-01

    The objective of this study was to identify task and vehicle factors that may affect driver situation awareness (SA) and its relationship to performance, particularly in strategic (navigation) tasks. An experiment was conducted to assess the effects of in-vehicle navigation aids and reliability on driver SA and performance in a simulated navigation task. A total of 20 participants drove a virtual car and navigated a large virtual suburb. They were required to follow traffic signs and navigation directions from either a human aid via a mobile phone or an automated aid presented on a laptop. The navigation aids operated under three different levels of information reliability (100%, 80% and 60%). A control condition was used in which each aid presented a telemarketing survey and participants navigated using a map. Results revealed perfect navigation information generally improved driver SA and performance compared to unreliable navigation information and the control condition (task-irrelevant information). In-vehicle automation appears to mediate the relationship of driver SA to performance in terms of operational and strategic (navigation) behaviours. The findings of this work support consideration of driver SA in the design of future vehicle automation for navigation tasks.

  13. 78 FR 63208 - UPDATE-Meeting of the Community Preventive Services Task Force (Task Force)

    Science.gov (United States)

    2013-10-23

    ... Services Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention (CDC), Department of... Force (Task Force). The in-person Task Force meeting is being replaced by an abbreviated conference call... necessary scientific and logistical support for the meeting. The Task Force is an independent,......

  14. 78 FR 2996 - Meeting of the Community Preventive Services Task Force (Task Force)

    Science.gov (United States)

    2013-01-15

    ... Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention (CDC), Department of Health... Prevention (CDC) announces the next meeting of the Community Preventive Services Task Force (Task Force). The Task Force is independent and nonfederal. Its members are nationally known leaders in public...

  15. 77 FR 56845 - Meeting of the Community Preventive Services Task Force (Task Force)

    Science.gov (United States)

    2012-09-14

    ... Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention (CDC), Department of Health... Prevention (CDC) announces the next meeting of the Community Preventive Services Task Force (Task Force). The Task Force is independent and nonfederal. Its members are nationally known leaders in public...

  16. 78 FR 59939 - Meeting of the Community Preventive Services Task Force (Task Force)

    Science.gov (United States)

    2013-09-30

    ... Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention (CDC), Department of Health..., announcing the next meeting of the Community Preventive Services Task Force (Task Force). The document did... inability to attend the Task Force meeting due to the strict security regulations on federal...

  17. Learner-Learner Interaction during Collaborative Pragmatic Tasks: The Role of Cognitive and Pragmatic Task Demands

    Science.gov (United States)

    Kim, YouJin; Taguchi, Naoko

    2016-01-01

    Previous task complexity studies have suggested that learners produce more negotiation of meaning opportunities during complex tasks than simple tasks (Robinson, 2011). The present study builds on the existing task complexity literature by examining the impact of task complexity and pragmatic situational demands on the number of learning…

  18. One Night of Sleep Deprivation Affects Reaction Time, but Not Interference or Facilitation in a Stroop Task

    Science.gov (United States)

    Cain, Sean W.; Silva, Edward J.; Chang, Anne-Marie; Ronda, Joseph M.; Duffy, Jeanne F.

    2011-01-01

    The Stroop color-naming task is one of the most widely studied tasks involving the inhibition of a prepotent response, regarded as an executive function. Several studies have examined performance on versions of the Stroop task under conditions of acute sleep deprivation. Though these studies revealed effects on Stroop performance, the results…

  19. Effects of a thermal-insulating mouse pad on temperature of forearm and hand during computer tasks

    NARCIS (Netherlands)

    E.M. Meijer; M.A.G. Formanoy; B. Visser; J.K. Sluiter; M.H.W. Frings-Dresen

    2006-01-01

    This laboratory experiment studied the effects of a thermal-insulating mouse pad on arm temperature and comfort during computer work. Fourteen subjects performed two 20-min computer tasks ( a mouse task and a combined task alternating keyboard and mouse use), under three conditions, namely with: 1)

  20. One Night of Sleep Deprivation Affects Reaction Time, but Not Interference or Facilitation in a Stroop Task

    Science.gov (United States)

    Cain, Sean W.; Silva, Edward J.; Chang, Anne-Marie; Ronda, Joseph M.; Duffy, Jeanne F.

    2011-01-01

    The Stroop color-naming task is one of the most widely studied tasks involving the inhibition of a prepotent response, regarded as an executive function. Several studies have examined performance on versions of the Stroop task under conditions of acute sleep deprivation. Though these studies revealed effects on Stroop performance, the results…

  1. Communicate only when necessary: Cooperative tasking for multi-agent systems

    CERN Document Server

    Karimadini, Mohammad

    2011-01-01

    New advances in large scale distributed systems have amazingly offered complex functionalities through parallelism of simple and rudimentary components. The key issue in cooperative control of multi-agent systems is the synthesis of local control and interaction rules among the agents such that the entire controlled system achieves a desired global behavior. For this purpose, three fundamental problems have to be addressed: (1) task decomposition for top-down design, such that the fulfillment of local tasks guarantees the satisfaction of the global task, by the team; (2) fault-tolerant top-down design, such that the global task remains decomposable and achievable, in spite of some failures, and (3) design of interactions among agents to make an undecomposable task decomposable and achievable in a top-down framework. The first two problems have been addressed in our previous works, by identifying necessary and sufficient conditions for task automaton decomposition, and fault-tolerant task decomposability. This...

  2. Live-social-video reward maintains joystick task performance in bonnet macaques.

    Science.gov (United States)

    Andrews, M W; Rosenblum, L A

    1993-12-01

    A number of studies have now indicated that monkeys of several species will perform hundreds of food-rewarded joystick tasks on a daily basis. Our goal in this study was to identify the level of joystick task performance that could be maintained by 10 sec. of live, color video of a conspecific social group contingent upon the completion of a joystick task. The subjects were five individually housed bonnet macaques that were highly experienced on joystick tasks. Performance with social-video reward was compared to that maintained by a 190-mg banana-flavored pellet reward and to a nonreward condition. Comparable levels of task activity were maintained by both video and pellet reward, whereas task activity nearly ceased in the absence of reward. Four of the five monkeys increased their levels of task activity between the first and second weeks of social-video reward.

  3. Embedded interruptions and task complexity influence schema-related cognitive load progression in an abstract learning task.

    Science.gov (United States)

    Wirzberger, Maria; Esmaeili Bijarsari, Shirin; Rey, Günter Daniel

    2017-09-01

    Cognitive processes related to schema acquisition comprise an essential source of demands in learning situations. Since the related amount of cognitive load is supposed to change over time, plausible temporal models of load progression based on different theoretical backgrounds are inspected in this study. A total of 116 student participants completed a basal symbol sequence learning task, which provided insights into underlying cognitive dynamics. Two levels of task complexity were determined by the amount of elements within the symbol sequence. In addition, interruptions due to an embedded secondary task occurred at five predefined stages over the task. Within the resulting 2x5-factorial mixed between-within design, the continuous monitoring of efficiency in learning performance enabled assumptions on relevant resource investment. From the obtained results, a nonlinear change of learning efficiency over time seems most plausible in terms of cognitive load progression. Moreover, different effects of the induced interruptions show up in conditions of task complexity, which indicate the activation of distinct cognitive mechanisms related to structural aspects of the task. Findings are discussed in the light of evidence from research on memory and information processing. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. A case of 'task-switching acalculia'.

    Science.gov (United States)

    Domahs, Frank; Benke, Thomas; Delazer, Margarete

    2011-02-01

    In this study we describe a patient (FR) with left frontal lesions due to a cerebrovascular disorder of embolic origin. Beyond a general slowness, FR showed deficits in simple multiplication only when problems were presented in a mixed operations list (multiplication, addition, and subtraction), while no such deficits were observed for the same multiplication problems in blocked presentation. Deficits were restricted to trials directly affected by a switch (increased switch costs), but not to subsequent trials (no increased mixing costs). Thus, we provide the first detailed description of a condition which could be termed 'task-switching acalculia' in a stroke patient. This case highlights the need for mixed operation lists in the diagnosis of acalculia.

  5. The effect of haptic guidance and visual feedback on learning a complex tennis task.

    Science.gov (United States)

    Marchal-Crespo, Laura; van Raai, Mark; Rauter, Georg; Wolf, Peter; Riener, Robert

    2013-11-01

    While haptic guidance can improve ongoing performance of a motor task, several studies have found that it ultimately impairs motor learning. However, some recent studies suggest that the haptic demonstration of optimal timing, rather than movement magnitude, enhances learning in subjects trained with haptic guidance. Timing of an action plays a crucial role in the proper accomplishment of many motor skills, such as hitting a moving object (discrete timing task) or learning a velocity profile (time-critical tracking task). The aim of the present study is to evaluate which feedback conditions-visual or haptic guidance-optimize learning of the discrete and continuous elements of a timing task. The experiment consisted in performing a fast tennis forehand stroke in a virtual environment. A tendon-based parallel robot connected to the end of a racket was used to apply haptic guidance during training. In two different experiments, we evaluated which feedback condition was more adequate for learning: (1) a time-dependent discrete task-learning to start a tennis stroke and (2) a tracking task-learning to follow a velocity profile. The effect that the task difficulty and subject's initial skill level have on the selection of the optimal training condition was further evaluated. Results showed that the training condition that maximizes learning of the discrete time-dependent motor task depends on the subjects' initial skill level. Haptic guidance was especially suitable for less-skilled subjects and in especially difficult discrete tasks, while visual feedback seems to benefit more skilled subjects. Additionally, haptic guidance seemed to promote learning in a time-critical tracking task, while visual feedback tended to deteriorate the performance independently of the task difficulty and subjects' initial skill level. Haptic guidance outperformed visual feedback, although additional studies are needed to further analyze the effect of other types of feedback visualization on

  6. Time to task failure and motor cortical activity depend on the type of feedback in visuomotor tasks.

    Directory of Open Access Journals (Sweden)

    Benedikt Lauber

    Full Text Available The present study aimed to elucidate whether the type of feedback influences the performance and the motor cortical activity when executing identical visuomotor tasks. For this purpose, time to task failure was measured during position- and force-controlled muscular contractions. Subjects received either visual feedback about the force produced by pressing a force transducer or about the actual position between thumb and index finger. Participants were instructed to either match the force level of 30% MVC or the finger position corresponding to the thumb and index finger angle at this contraction intensity. Subjects demonstrated a shorter time to task failure when they were provided with feedback about their joint position (11.5 ± 6.2 min instead of force feedback (19.2 ± 12.8 min; P = 0.01. To test differences in motor cortical activity between position- and force-controlled contractions, subthreshold transcranial magnetic stimulation (subTMS was applied while executing submaximal (20% MVC contractions. SubTMS resulted in a suppression of the first dorsal interosseus muscle (FDI EMG in both tasks. However, the mean suppression for the position-controlled task was significantly greater (18.6 ± 9.4% vs. 13.3 ± 7.5%; P = 0.025 and lasted longer (13.9 ± 7.5 ms vs. 9.3 ± 4.3 ms; P = 0.024 compared to the force-controlled task. The FDI background EMG obtained without stimulation was comparable in all conditions. The present results demonstrate that the presentation of different feedback modalities influences the time to task failure as well as the cortical activity. As only the feedback was altered but not the mechanics of the task, the present results add to the body of evidence that suggests that the central nervous system processes force and position information in different ways.

  7. Quality of Language and Purpose of Task: Patterns of Learners' Language on Two Oral Communication Tasks.

    Science.gov (United States)

    Bygate, Martin

    1999-01-01

    Examines the performance of Hungarian secondary school students on two types of unscripted tasks--an argument task and a narrative task. Focuses on grammatical patterns of learner language, and reports significant differences in the learners' performance. (Author/VWL)

  8. Unmasking of an early laser evoked potential by a point localization task

    DEFF Research Database (Denmark)

    Valeriani, M.; Restuccia, D.; Le Pera, D.

    2000-01-01

    Objectives: The investigation of the CO2 laser evoked potential (LEP) modifications following a point localization task. Methods: LEPs were recorded from 10 healthy subjects in two different conditions. (1) Task condition: laser stimuli were shifted among 3 different locations on the right hand...... dorsum, and the subjects were asked to identify the stimulated area. The mean error rate in point localization was 4.5%. (2) Non-task condition: laser pulses were delivered on the first intermetacarpal space, and the subject was asked to count the number of stimuli. The mean error rate in counting was 5...

  9. Preliminary results of mental workload and task engagement assessment using electroencephalogram in a space suit.

    Science.gov (United States)

    Rabbi, Ahmed F; Zony, Abongwa N; de Leon, Pablo; Fazel-Rezai, Reza

    2012-01-01

    In this paper, we present preliminary results of subject's mental workload and task engagement assessment in an experimental space suit. We have quantified the mental workload and task engagement based on changes in electroencephalogram (EEG). EEG signals were collected from subjects scalp using a commercial wireless EEG device in two experimental conditions - when subjects did not wear space suit (control condition) and when subjects wore space suit. Brain state changes were estimated and compared with the direct responses for different tasks and different conditions. We found that the spacesuit experiment introduced a greater mental workload where subject's stress levels were higher than control experiment.

  10. Delays and user performance in human-computer-network interaction tasks.

    Science.gov (United States)

    Caldwell, Barrett S; Wang, Enlie

    2009-12-01

    This article describes a series of studies conducted to examine factors affecting user perceptions, responses, and tolerance for network-based computer delays affecting distributed human-computer-network interaction (HCNI) tasks. HCNI tasks, even with increasing computing and network bandwidth capabilities, are still affected by human perceptions of delay and appropriate waiting times for information flow latencies. Conducted were 6 laboratory studies with university participants in China (Preliminary Experiments 1 through 3) and the United States (Experiments 4 through 6) to examine users' perceptions of elapsed time, effect of perceived network task performance partners on delay tolerance, and expectations of appropriate delays based on task, situation, and network conditions. Results across the six experiments indicate that users' delay tolerance and estimated delay were affected by multiple task and expectation factors, including task complexity and importance, situation urgency and time availability, file size, and network bandwidth capacity. Results also suggest a range of user strategies for incorporating delay tolerance in task planning and performance. HCNI user experience is influenced by combinations of task requirements, constraints, and understandings of system performance; tolerance is a nonlinear function of time constraint ratios or decay. Appropriate user interface tools providing delay feedback information can help modify user expectations and delay tolerance. These tools are especially valuable when delay conditions exceed a few seconds or when task constraints and system demands are high. Interface designs for HCNI tasks should consider assistant-style presentations of delay feedback, information freshness, and network characteristics. Assistants should also gather awareness of user time constraints.

  11. Advert saliency distracts children's visual attention during task-oriented internet use

    Directory of Open Access Journals (Sweden)

    Nils eHolmberg

    2014-02-01

    Full Text Available The general research question of the present study was to assess the impact of visually salient online adverts on children's task-oriented internet use. In order to answer this question, an experimental study was constructed in which 9-year-old and 12-year-old Swedish children were asked to solve a number of tasks while interacting with a mockup website. In each trial, web adverts in several saliency conditions were presented. By both measuring children's task accuracy, as well as the visual processing involved in solving these tasks, this study allows us to infer how two types of visual saliency affect children's attentional behavior, and whether such behavioral effects also impacts their task performance. Analyses show that low-level visual features and task relevance in online adverts have different effects on performance measures and process measures respectively. Whereas task performance is stable with regard to several advert saliency conditions, a marked effect is seen on children's gaze behavior. On the other hand, task performance is shown to be more sensitive to individual differences such as age, gender and level of gaze control. The results provide evidence about cognitive and behavioral distraction effects in children's task-oriented internet use caused by visual saliency in online adverts. The experiment suggests that children to some extent are able to compensate for behavioral effects caused by distracting visual stimuli when solving prospective memory tasks. Suggestions are given for further research into the interdiciplinary area between media research and cognitive science.

  12. Advert saliency distracts children's visual attention during task-oriented internet use.

    Science.gov (United States)

    Holmberg, Nils; Sandberg, Helena; Holmqvist, Kenneth

    2014-01-01

    The general research question of the present study was to assess the impact of visually salient online adverts on children's task-oriented internet use. In order to answer this question, an experimental study was constructed in which 9- and 12-year-old Swedish children were asked to solve a number of tasks while interacting with a mockup website. In each trial, web adverts in several saliency conditions were presented. By both measuring children's task accuracy, as well as the visual processing involved in solving these tasks, this study allows us to infer how two types of visual saliency affect children's attentional behavior, and whether such behavioral effects also impacts their task performance. Analyses show that low-level visual features and task relevance in online adverts have different effects on performance measures and process measures respectively. Whereas task performance is stable with regard to several advert saliency conditions, a marked effect is seen on children's gaze behavior. On the other hand, task performance is shown to be more sensitive to individual differences such as age, gender and level of gaze control. The results provide evidence about cognitive and behavioral distraction effects in children's task-oriented internet use caused by visual saliency in online adverts. The experiment suggests that children to some extent are able to compensate for behavioral effects caused by distracting visual stimuli when solving prospective memory tasks. Suggestions are given for further research into the interdiciplinary area between media research and cognitive science.

  13. TASKS OF THE "INTENSIVE READING"

    Institute of Scientific and Technical Information of China (English)

    伍向梅

    1984-01-01

    @@ To Chinese students who are learning English as a foreign language, the "intensive reading" course is of great practical value,especially in the intermediate stage,i.e.senior-middle school or the second or third year in college. "Intensive reading"implies the recognition of the configuration, pronunciation, grammatical inflexion and structure of words, sentences, paragraphs, and the whole text. It strength ens listening and speaking, affords language, content, and models for writing.It helps the student lay a solid foundation of the language. Thus, the tasks assigned to the "intensive reading" are worth studying.

  14. Task descriptions versus use cases

    DEFF Research Database (Denmark)

    Lauesen, Søren; Kuhail, Mohammad Amin

    2011-01-01

    Use cases are widely used as a substantial part of requirements, also when little programming is expected (COTS-based systems, Commercial-Off-The-Shelf). Are use cases effective as requirements? To answer this question, we invited professionals and researchers to specify requirements for the same...... project: Acquire a new system to support a hotline. Among the 15 replies, eight used traditional use cases that specified a dialog between user and system. Seven used a related technique, task description, which specified the customer’s needs without specifying a dialog. It also allowed the analyst...

  15. Use cases versus task descriptions

    DEFF Research Database (Denmark)

    Lauesen, Søren; Kuhail, Mohammad Amin

    2011-01-01

    Abstract. [Context and motivation] Use cases are widely used as a substantial part of requirements, also when little programming is expected (COTS-based systems). [Question/problem] Are use cases effective as requirements? To an-swer this question, we invited professionals and researchers...... to specify require-ments for the same project: Acquire a new system to support a hotline. [Princi-pal ideas/results] Among the 15 replies, eight used traditional use cases that specified a dialog between users and system. Seven used a related technique, task description, which specified the customer's needs...

  16. EFFORTS Sub-task report on task 4.2: Cold forming

    DEFF Research Database (Denmark)

    Andreasen, Jan Lasson; Christensen, Thomas Vennick; Bay, Niels

    1999-01-01

    Task 4.2 is a sub-task of task 4: Physical modelling validation. In sub-task 4.2 experimental analysis of cold forming as regards form filling, interface stresses and forces and moments using sof model materials have been carried out.......Task 4.2 is a sub-task of task 4: Physical modelling validation. In sub-task 4.2 experimental analysis of cold forming as regards form filling, interface stresses and forces and moments using sof model materials have been carried out....

  17. U.S. Preventive Services Task Force

    Science.gov (United States)

    ... Public Comment In an effort to make the U.S. Preventive Services Task Force (USPSTF) recommendations clearer and ... Current as of: May 2016 Internet Citation: Home . U.S. Preventive Services Task Force. August 2016. https://www. ...

  18. Sex, Task, and Behavioral Flexibility Effects on Leadership Perceptions.

    Science.gov (United States)

    Hall; Workman; Marchioro

    1998-04-01

    The effects of sex and behavioral flexibility on leader perceptions were examined in small groups performing under two task conditions. We predicted, based on theory and previous empirical research, that leadership perceptions would be higher for: (1) persons higher in three indicators of behavioral flexibility (self-monitoring, self-reported behavioral capabilities, and androgyny), (2) males in general, and (3) tasks that were sex-congruent. Results showed significant, strong support for behavioral flexibility and sex effects and weak support for the effects of sex-congruent tasks. Exploratory analyses showed that perceived target capabilities mediated the effects of sex and behavioral flexibility. The discussion is organized around a theoretical model which suggests that target behavior and sex-based cues leading to leader categorization are in part mediated by inferred target capabilities. These capabilities show parallels to leadership-relevant traits such as masculinity, dominance, extroversion, and adjustment, identified in early leadership research. Copyright 1998 Academic Press.

  19. BODY CONDITION

    African Journals Online (AJOL)

    Andrew Taylor

    seasonal variation that could be used in management decisions. ... To assess muscle and fat content, the leg was completely separated into meat, bone, ..... The seasonal variation in body condition of mountain reedbuck can be explained by ...

  20. Conditional Punishment

    OpenAIRE

    Kamei, Kenju

    2014-01-01

    We elicit human conditional punishment types by conducting experiments. We find that their punishment decisions to an individual are on average significantly positively proportional to other members’ punishment decisions to that individual.

  1. Differential Endocannabinoid Regulation of Extinction in Appetitive and Aversive Barnes Maze Tasks

    Science.gov (United States)

    Harloe, John P.; Thorpe, Andrew J.; Lichtman, Aron H.

    2008-01-01

    CB[subscript 1] receptor-compromised animals show profound deficits in extinguishing learned behavior from aversive conditioning tasks, but display normal extinction learning in appetitive operant tasks. However, it is difficult to discern whether the differential involvement of the endogenous cannabinoid system on extinction results from the…

  2. Cognitive tasks during expectation affect the congruency ERP effects to facial expressions.

    Science.gov (United States)

    Lin, Huiyan; Schulz, Claudia; Straube, Thomas

    2015-01-01

    Expectancy congruency has been shown to modulate event-related potentials (ERPs) to emotional stimuli, such as facial expressions. However, it is unknown whether the congruency ERP effects to facial expressions can be modulated by cognitive manipulations during stimulus expectation. To this end, electroencephalography (EEG) was recorded while participants viewed (neutral and fearful) facial expressions. Each trial started with a cue, predicting a facial expression, followed by an expectancy interval without any cues and subsequently the face. In half of the trials, participants had to solve a cognitive task in which different letters were presented for target letter detection during the expectancy interval. Furthermore, facial expressions were congruent with the cues in 75% of all trials. ERP results revealed that for fearful faces, the cognitive task during expectation altered the congruency effect in N170 amplitude; congruent compared to incongruent fearful faces evoked larger N170 in the non-task condition but the congruency effect was not evident in the task condition. Regardless of facial expression, the congruency effect was generally altered by the cognitive task during expectation in P3 amplitude; the amplitudes were larger for incongruent compared to congruent faces in the non-task condition but the congruency effect was not shown in the task condition. The findings indicate that cognitive tasks during expectation reduce the processing of expectation and subsequently, alter congruency ERP effects to facial expressions.

  3. Divergent Effects of Cognitive Load on Quiet Stance and Task-Linked Postural Coordination

    Science.gov (United States)

    Mitra, Suvobrata; Knight, Alec; Munn, Alexandra

    2013-01-01

    Performing a cognitive task while maintaining upright stance can lead to increased or reduced body sway depending on tasks and experimental conditions. Because greater sway is commonly taken to indicate loosened postural control, and vice versa, the precise impact of cognitive load on postural stability has remained unclear. In much of the large…

  4. The Effects of Background Music on Primary School Pupils' Task Performance.

    Science.gov (United States)

    Hallam, Susan; Price, John; Katsarou, Georgia

    2002-01-01

    Presents two studies that explored the effects of music perceived as calming and relaxing on arithmetic and memory performance tasks of 10- to 12-year-old children. Reports that the calming music led to better performance on both tasks when compared with the non-music condition. Includes references. (CMK)

  5. Postpassage Questions: Task and Reader Effects on Comprehension and Metacomprehension Processes.

    Science.gov (United States)

    Davey, Beth

    1987-01-01

    Explores the effects of question task conditions on reading comprehension and metacomprehension for proficient readers, disabled readers, and deaf readers. Finds several significant interaction effects for both demonstrated and perceived comprehension performance in selected-response and constructed-response question tasks under both lookback and…

  6. Support of the collaborative inquiry learning process: influence of support on task and team regulation

    NARCIS (Netherlands)

    Saab, N.; van Joolingen, W.; van Hout-Wolters, B.

    2012-01-01

    Regulation of the learning process is an important condition for efficient and effective learning. In collaborative learning, students have to regulate their collaborative activities (team regulation) next to the regulation of their own learning process focused on the task at hand (task regulation).

  7. Using Choice to Increase On-Task Behavior in Individuals with Traumatic Brain Injury

    Science.gov (United States)

    Tasky, Kim K.; Rudrud, Eric H.; Schulze, Kimberly A.; Rapp, John T.

    2008-01-01

    An ABA'B design was used to evaluate the effects of choice on task engagement for 3 adults who had been diagnosed with traumatic brain injury. A yoked-control condition, in which tasks that were selected by each participant were assigned subsequently to that participant by a trainer, was implemented to help distinguish between the effects of task…

  8. Support of the collaborative inquiry learning process: influence of support on task and team regulation

    NARCIS (Netherlands)

    N. Saab; W. van Joolingen; B. van Hout-Wolters

    2012-01-01

    Regulation of the learning process is an important condition for efficient and effective learning. In collaborative learning, students have to regulate their collaborative activities (team regulation) next to the regulation of their own learning process focused on the task at hand (task regulation).

  9. Task Difficulty in Oral Speech Act Production

    Science.gov (United States)

    Taguchi, Naoko

    2007-01-01

    This study took a pragmatic approach to examining the effects of task difficulty on L2 oral output. Twenty native English speakers and 59 Japanese students of English at two different proficiency levels produced speech acts of requests and refusals in a role play task. The task had two situation types based on three social variables:…

  10. A Task Is a Task Is a Task Is a Task... Or Is It? Researching Telecollaborative Teacher Competence Development--The Need for More Qualitative Research

    Science.gov (United States)

    Müller-Hartmann, Andreas

    2016-01-01

    The concept of task has become central not only to an understanding of language learning per se, but also to the design and research of Online Intercultural Exchanges (OIEs). While research on the design of tasks in OIEs has been very productive, we still lack insights into how teachers develop competences in task design on the micro-level.…

  11. Task Repetition and Second Language Speech Processing

    Science.gov (United States)

    Lambert, Craig; Kormos, Judit; Minn, Danny

    2017-01-01

    This study examines the relationship between the repetition of oral monologue tasks and immediate gains in L2 fluency. It considers the effect of aural-oral task repetition on speech rate, frequency of clause-final and midclause filled pauses, and overt self-repairs across different task types and proficiency levels and relates these findings to…

  12. Imagining Mathematics Teaching via Scripting Tasks

    Science.gov (United States)

    Zazkis, Rina; Sinclair, Nathalie

    2013-01-01

    We discuss an innovative task used in teacher education--Lesson Play--that involves presenting a lesson in the form of an interaction between a teacher and students. We describe the motivation for the development of this task and, through specific examples, describe the iterative design process in which the task was refined and improved. We…

  13. What Makes a Mathematical Task Interesting?

    Science.gov (United States)

    Nyman, Rimma

    2016-01-01

    The study addresses the question of what makes a mathematical task interesting to the 9th year students. Semi-structured interviews were carried out with 15 students of purposive selection of the 9th year. The students were asked to recall a task they found interesting and engaging during the past three years. An analysis of the tasks was made…

  14. Task Complexity and Second Language Narrative Discourse.

    Science.gov (United States)

    Robinson, Peter

    1995-01-01

    Examines differences in oral narrative discourse of adult second-language learners of English on narrative tasks simulating the ability to describe events in the Here-and-Now versus the There-and-Then. Results indicate that complex tasks elicit less fluent, but more accurate and complex narration than do simpler tasks. (90 references) (Author/CK)

  15. Research on Task-Based Language Teaching

    Institute of Scientific and Technical Information of China (English)

    赵玲玲

    2014-01-01

    This paper begins with a brief introduction to Task-Based Language Teaching(TBLT).The Task-Based Language Teaching(TBLA) has gained popularity in the field of language teaching since the last decade of the 20th century.This paper mainly il ustrates the definition,importance and approaches of Task-Based Language Teaching(TBLA).

  16. San Joaquin River Up-Stream DO TMDL Project Task 4: MonitoringStudy Interim Task Report #3

    Energy Technology Data Exchange (ETDEWEB)

    Stringfellow, William; Borglin, Sharon; Dahlgren, Randy; Hanlon,Jeremy; Graham, Justin; Burks, Remie; Hutchinson, Kathleen

    2007-03-30

    The purpose of the Dissolved Oxygen Total Maximum Daily LoadProject (DO TMDLProject) is to provide a comprehensive understanding ofthe sources and fate of oxygen consuming materials in the San JoaquinRiver (SJR) watershed between Channel Point and Lander Avenue (upstreamSJR). When completed, this study will provide the stakeholders anunderstanding of the baseline conditions of the basin, provide input foran allocation decision, and provide the stakeholders with a tool formeasuring the impact of any waterquality management program that may beimplemented as part of the DO TMDL process. Previous studies haveidentified algal biomass as the most significant oxygen-demandingsubstance in the DO TMDL Project study-area between of Channel Point andLander Ave onthe SJR. Other oxygen-demanding substances found in theupstream SJR include ammonia and organic carbon from sources other thanalgae. The DO TMDL Project study-area contains municipalities, dairies,wetlands, cattle ranching, irrigated agriculture, and industries thatcould potentially contribute biochemical oxygen demand (BOD) to the SJR.This study is designed to discriminate between algal BOD and othersources of BOD throughout the entire upstream SJR watershed. Algalbiomass is not a conserved substance, but grows and decays in the SJR;hence, characterization of oxygen-demanding substances in the SJR isinherently complicated and requires an integrated effort of extensivemonitoring, scientific study, and modeling. In order to achieve projectobjectives, project activities were divided into a number of Tasks withspecific goals and objectives. In this report, we present the results ofmonitoring and research conducted under Task 4 of the DO TMDL Project.The major objective of Task 4 is to collect sufficient hydrologic (flow)and water quality (WQ) data to characterize the loading of algae, otheroxygen-demanding materials, and nutrients fromindividual tributaries andsub-watersheds of the upstream SJR between Mossdale and

  17. Experimental evaluation of the influence of various rests on task performance

    Energy Technology Data Exchange (ETDEWEB)

    Nagasaka, Akihiko; Hirose, Ayako [Central Research Inst. of Electric Power Industry, Tokyo (Japan)

    2000-01-01

    This report deals with the result of the experiment that 8 subjects had executed adding task and search task. They executed each task in 80 minutes under 5 conditions: (1) with no rest, and with 4 kinds of 20 minutes rests, in which they (2) opened eyes, (3) closed eyes, (4) closed eyes with listening classic music and (5) closed eyes with feet massage, in the middle of the task. The results of analysis of variance with the task performance in the latter half, there were significant differences between each condition with every subject in adding task, and with 6 subjects in search task. However, the orders of the task performance with each condition were not the same by each subject. It was suggested that transition of the arousal levels under the rest was related to the effects of the rest rather than the subjects' taste in rests. In the rest, the percentage of {alpha} wave of electroencephalogram and the coefficient of variation of R-R interval (time interval of heart beats) were increased than in executing task. The mean Kendall's rank correlation of coefficient with the order of increase rate of {alpha}/{beta} wave and the task performance in the latter half was slightly negative in adding task, but was about 0.4 in search task. From these results, about six requirements for 'an effective rest' were able to be mentioned, for example, 'the devices that raises the arousal levels is carried out just before a rest end'. (author)

  18. TASK-1 and TASK-3 may form heterodimers in human atrial cardiomyocytes.

    Science.gov (United States)

    Rinné, Susanne; Kiper, Aytug K; Schlichthörl, Günter; Dittmann, Sven; Netter, Michael F; Limberg, Sven H; Silbernagel, Nicole; Zuzarte, Marylou; Moosdorf, Rainer; Wulf, Hinnerk; Schulze-Bahr, Eric; Rolfes, Caroline; Decher, Niels

    2015-04-01

    TASK-1 channels have emerged as promising drug targets against atrial fibrillation, the most common arrhythmia in the elderly. While TASK-3, the closest relative of TASK-1, was previously not described in cardiac tissue, we found a very prominent expression of TASK-3 in right human auricles. Immunocytochemistry experiments of human right auricular cardiomyocytes showed that TASK-3 is primarily localized at the plasma membrane. Single-channel recordings of right human auricles in the cell-attached mode, using divalent-cation-free solutions, revealed a TASK-1-like channel with a single-channel conductance of about 30pS. While homomeric TASK-3 channels were not found, we observed an intermediate single-channel conductance of about 55pS, possibly reflecting the heteromeric channel formed by TASK-1 and TASK-3. Subsequent experiments with TASK-1/TASK-3 tandem channels or with co-expressed TASK-1 and TASK-3 channels in HEK293 cells or Xenopus oocytes, supported that the 55pS channels observed in right auricles have electrophysiological characteristics of TASK-1/TASK-3 heteromers. In addition, co-expression experiments and single-channel recordings suggest that heteromeric TASK-1/TASK-3 channels have a predominant surface expression and a reduced affinity for TASK-1 blockers. In summary, the evidence for heteromeric TASK-1/TASK-3 channel complexes together with an altered pharmacologic response to TASK-1 blockers in vitro is likely to have further impact for studies isolating ITASK-1 from cardiomyocytes and for the development of drugs specifically targeting TASK-1 in atrial fibrillation treatment.

  19. Working memory and acquisition of implicit knowledge by imagery training, without actual task performance.

    Science.gov (United States)

    Helene, A F; Xavier, G F

    2006-04-28

    This study investigated acquisition of a mirror-reading skill via imagery training, without the actual performance of a mirror-reading task. In experiment I, healthy volunteers simulated writing on an imaginary, transparent screen placed at eye level, which could be read by an experimenter facing the subject. Performance of this irrelevant motor task required the subject to imagine the letters inverted, as if seen in a mirror from their own point of view (imagery training). A second group performed the same imagery training interspersed with a complex, secondary spelling and counting task. A third, control, group simply wrote the words as they would normally appear from their own point of view. After training with 300 words, all subjects were tested in a mirror-reading task using 60 non-words, constructed according to acceptable letter combinations of the Portuguese language. Compared with control subjects, those exposed to imagery training, including those who switched between imagery and the complex task, exhibited shorter reading times in the mirror-reading task. Experiment II employed a 2 x 3 design, including two training conditions (imagery and actual mirror-reading) and three competing task conditions (a spelling and counting switching task, a visual working memory concurrent task, and no concurrent task). Training sessions were interspersed with mirror-reading testing sessions for non-words, allowing evaluation of the mirror-reading acquisition process during training. The subjects exposed to imagery training acquired the mirror-reading skill as quickly as those exposed to the actual mirror-reading task. Further, performance of concurrent tasks together with actual mirror-reading training severely disrupted mirror-reading skill acquisition; this interference effect was not seen in subjects exposed to imagery training and performance of the switching and the concurrent tasks. These results unequivocally show that acquisition of implicit skills by top

  20. Multisensory perceptual learning is dependent upon task difficulty.

    Science.gov (United States)

    De Niear, Matthew A; Koo, Bonhwang; Wallace, Mark T

    2016-11-01

    There has been a growing interest in developing behavioral tasks to enhance temporal acuity as recent findings have demonstrated changes in temporal processing in a number of clinical conditions. Prior research has demonstrated that perceptual training can enhance temporal acuity both within and across different sensory modalities. Although certain forms of unisensory perceptual learning have been shown to be dependent upon task difficulty, this relationship has not been explored for multisensory learning. The present study sought to determine the effects of task difficulty on multisensory perceptual learning. Prior to and following a single training session, participants completed a simultaneity judgment (SJ) task, which required them to judge whether a visual stimulus (flash) and auditory stimulus (beep) presented in synchrony or at various stimulus onset asynchronies (SOAs) occurred synchronously or asynchronously. During the training session, participants completed the same SJ task but received feedback regarding the accuracy of their responses. Participants were randomly assigned to one of three levels of difficulty during training: easy, moderate, and hard, which were distinguished based on the SOAs used during training. We report that only the most difficult (i.e., hard) training protocol enhanced temporal acuity. We conclude that perceptual training protocols for enhancing multisensory temporal acuity may be optimized by employing audiovisual stimuli for which it is difficult to discriminate temporal synchrony from asynchrony.

  1. Task-irrelevant blindsight and the impact of invisible stimuli

    Directory of Open Access Journals (Sweden)

    Petra eStoerig

    2011-04-01

    Full Text Available Despite their subjective invisibility, stimuli presented within regions of absolute cortical blindness can both guide forced-choice behaviour when they are task-relevant and modulate responses to visible targets when they are task-irrelevant. We here tested three hemianopic patients to learn whether their performance in an attention-demanding rapid serial visual presentation task would be affected by task-irrelevant stimuli. Per trial, nine black letters and one white target-letter appeared briefly at fixation; the white letter was to be named at the end of each trial. On 50% of trials, a task-irrelevant disk (-.6 log contrast was presented to the blind field; in separate blocks, the same or a very low negative contrast distractor was presented to the sighted field. Mean error rates were high and independent of distractor condition, although the high contrast sighted-field disk impaired performance significantly in one participant. However, when trials with and without distractors were considered separately, performance was most impaired by the high contrast disk in the blind field, whereas the same disk in the sighted field had no effect. As this disk was least visible in the blind and most visible in the sighted field, attentional suppression was inversely related to visibility. We suggest that visual awareness, or the processes that generate it and are compromised in the blind hemisphere, enhances or enables effective attentional suppression.

  2. Task-irrelevant blindsight and the impact of invisible stimuli.

    Science.gov (United States)

    Stoerig, Petra

    2011-01-01

    Despite their subjective invisibility, stimuli presented within regions of absolute cortical blindness can both guide forced-choice behavior when they are task-relevant and modulate responses to visible targets when they are task-irrelevant. We here tested three hemianopic patients to learn whether their performance in an attention-demanding rapid serial visual presentation task would be affected by task-irrelevant stimuli. Per trial, nine black letters and one white target letter appeared briefly at fixation; the white letter was to be named at the end of each trial. On 50% of trials, a task-irrelevant disk (-0.6 log contrast) was presented to the blind field; in separate blocks, the same or a very low negative contrast distractor was presented to the sighted field. Mean error rates were high and independent of distractor condition, although the high-contrast sighted-field disk impaired performance significantly in one participant. However, when trials with and without distractors were considered separately, performance was most impaired by the high-contrast disk in the blind field, whereas the same disk in the sighted field had no effect. As this disk was least visible in the blind and most visible in the sighted field, attentional suppression was inversely related to visibility. We suggest that visual awareness, or the processes that generate it and are compromised in the blind hemisphere, enhances or enables effective attentional suppression.

  3. Dynamic Task Performance, Cohesion, and Communications in Human Groups.

    Science.gov (United States)

    Giraldo, Luis Felipe; Passino, Kevin M

    2016-10-01

    In the study of the behavior of human groups, it has been observed that there is a strong interaction between the cohesiveness of the group, its performance when the group has to solve a task, and the patterns of communication between the members of the group. Developing mathematical and computational tools for the analysis and design of task-solving groups that are not only cohesive but also perform well is of importance in social sciences, organizational management, and engineering. In this paper, we model a human group as a dynamical system whose behavior is driven by a task optimization process and the interaction between subsystems that represent the members of the group interconnected according to a given communication network. These interactions are described as attractions and repulsions among members. We show that the dynamics characterized by the proposed mathematical model are qualitatively consistent with those observed in real-human groups, where the key aspect is that the attraction patterns in the group and the commitment to solve the task are not static but change over time. Through a theoretical analysis of the system we provide conditions on the parameters that allow the group to have cohesive behaviors, and Monte Carlo simulations are used to study group dynamics for different sets of parameters, communication topologies, and tasks to solve.

  4. Task dependency of motor adaptations to an acute noxious stimulation.

    Science.gov (United States)

    Hug, François; Hodges, Paul W; Tucker, Kylie

    2014-06-01

    This study explored motor adaptations in response to an acute noxious stimulation during three tasks that differed in the number of available degrees of freedom. Fifteen participants performed three isometric force-matched tasks (single leg knee extension, single leg squat, and bilateral leg squat) in three conditions (Control, Pain, and Washout). Pain was induced by injection of hypertonic saline into the vastus medialis muscle (VM; left leg). Supersonic shear imaging was used to measure muscle shear elastic modulus as this is considered to be an index of muscle stress. Surface electromyography (EMG) was recorded bilaterally from six muscles to assess changes in neural strategies. During tasks with fewer degrees of freedom (knee extension and single leg squat task), there was no change in VM EMG amplitude or VM shear elastic modulus. In contrast, during the bilateral leg squat, VM (-32.9 ± 15.8%; P leg (-10.0 ± 10.2%; P = 0.046). This work provides evidence that when an obvious solution is available to decrease stress on painful tissue, this option is selected. It confirms the fundamental assumption that motor adaptations to pain aim to alter load on painful tissue to protect for further pain and/or injury. The lack of adaptation observed during force-matched tasks with fewer degrees of freedom might be explained by the limited potential to redistribute stress or a high cost induced by such a compensation.

  5. Task modulates functional connectivity networks in free viewing behavior.

    Science.gov (United States)

    Seidkhani, Hossein; Nikolaev, Andrey R; Meghanathan, Radha Nila; Pezeshk, Hamid; Masoudi-Nejad, Ali; van Leeuwen, Cees

    2017-08-03

    In free visual exploration, eye-movement is immediately followed by dynamic reconfiguration of brain functional connectivity. We studied the task-dependency of this process in a combined visual search-change detection experiment. Participants viewed two (nearly) same displays in succession. First time they had to find and remember multiple targets among distractors, so the ongoing task involved memory encoding. Second time they had to determine if a target had changed in orientation, so the ongoing task involved memory retrieval. From multichannel EEG recorded during 200 ms intervals time-locked to fixation onsets, we estimated the functional connectivity using a weighted phase lag index at the frequencies of theta, alpha, and beta bands, and derived global and local measures of the functional connectivity graphs. We found differences between both memory task conditions for several network measures, such as mean path length, radius, diameter, closeness and eccentricity, mainly in the alpha band. Both the local and the global measures indicated that encoding involved a more segregated mode of operation than retrieval. These differences arose immediately after fixation onset and persisted for the entire duration of the lambda complex, an evoked potential commonly associated with early visual perception. We concluded that encoding and retrieval differentially shape network configurations involved in early visual perception, affecting the way the visual input is processed at each fixation. These findings demonstrate that task requirements dynamically control the functional connectivity networks involved in early visual perception. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Impatient Task Mapping in Elastic Cloud using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Nawfal A. Mehdi

    2011-01-01

    Full Text Available Problem statement: Task scheduling is the main factor that determines the performance of any distributed system. Cloud computing comes with a paradigm of distributed datacenters. Each datacenter consists of physical machines that host virtual machines to execute customers’ tasks. Resources allocation on the cloud is different from other paradigms and the mapping algorithms need to be adapted to the new characteristics. This study takes the problem of immediate task scheduling under an intercloud infrastructure using a genetic algorithm. An impatient task needs to be scheduled as soon as it enters the system taking into account the input and output files location and its QoS requirements. Approach: This study proposes an algorithm that can find a fast mapping using genetic algorithms with "exist if satisfy" condition to speed up the mapping process and ensures the respecting of all task deadlines. Cloudsim simulator was used to test the proposed algorithm with real datasets collected as a cloud benchmark. Mapping time and makespan are the performance metrics that are used to evaluate the proposed system. Results: The results show an improvement in the proposed system compared to MCT algorithm as illustrated throughout the study. Conclusion: Batch mapping via genetic algorithms with throughput as a fitness function can be used to map jobs to cloud resources.

  7. Exploring Conditions to Enhance Student/Host Family Interaction Abroad

    Science.gov (United States)

    Knight, Susan M.; Schmidt-Rinehart, Barbara C.

    2010-01-01

    This study investigates the role of task-based learning in the study abroad experience in order to enhance interaction with the host family. Tasks were incorporated into a Family Interaction Journal and implemented under four evolving, though different, conditions over a 5-year period. The conditions were: (1) home campus administered/student…

  8. Task relevance differentially shapes ventral visual stream sensitivity to visible and invisible faces

    DEFF Research Database (Denmark)

    Kouider, Sid; Barbot, Antoine; Madsen, Kristoffer Hougaard

    2016-01-01

    requires dissociating it from the top-down influences underlying conscious recognition. Here, using visual masking to abolish perceptual consciousness in humans, we report that functional magnetic resonance imaging (fMRI) responses to invisible faces in the fusiform gyrus are enhanced when they are task......-relevant, but suppressed when they are task-irrelevant compared to other object categories. Under conscious perceptual conditions, task-related modulations were also present but drastically reduced, with visible faces always eliciting greater activity in the fusiform gyrus compared to other object categories. Thus, task...

  9. fNIRS-based investigation of the Stroop task after TBI.

    Science.gov (United States)

    Plenger, Patrick; Krishnan, Kamini; Cloud, Matthew; Bosworth, Chris; Qualls, Devin; Marquez de la Plata, Carlos

    2016-06-01

    To evaluate neural changes during a Stroop task among individuals with TBI using functional near-infrared spectroscopy (fNIRS). Thirteen healthy controls and 14 patients with moderate to severe TBI were included in this study. Oxygenated hemoglobin (HbO) was recorded every tenth of a second using a 52-channel fNIRS unit. Data were acquired using a block design during a Stroop task (i.e., Condition A = Dot Color Naming, Condition B = Incongruent Condition). Visual stimuli were presented on a computer monitor. Behaviorally, response accuracy was similar between groups for condition A, but the TBI group made more errors than the control group during condition B. During condition A, the patient group demonstrated significant increases in HbO within bilateral frontal regions compared to controls (p TBI group (p TBI group performed as accurately as controls on the simpler dot color naming condition of the Stroop task, neural activity was greater within the frontal lobes during this relatively simple task among the TBI group suggesting neural inefficiency. Furthermore, the spatial distribution of neural activity related to the interference effect was not different among patients, suggesting the neural demand for the simpler task was comparable to that of the more cognitive demanding task among the TBI sample. The results suggest that fNIRS can identify frontal lobe inefficiency in TBI commonly observed with fMRI.

  10. Garbage Collection Scheduling of Aperiodic Tasks

    Institute of Scientific and Technical Information of China (English)

    Ning Zhang; Guang-Ze Xiong

    2009-01-01

    In the previous work of garbage collection (GC) models, scheduling analysis was given based on an assumption that there were no aperiodic mutator tasks. However, it is not true in practical real-time systems. The GC algorithm which can schedule aperiodic tasks is proposed, and the variance of live memory is analyzed. In this algorithm, active tasks are deferred to be processed by GC until the states of tasks become inactive, and the saved sporadic server time can be used to schedule aperiodic tasks. Scheduling the sample task sets demonstrates that this algorithm in this paper can schedule aperiodic tasks and decrease GC work. Thus, the GC algorithm proposed is more flexible and portable.

  11. Assessing Cognitive Load on Web Search Tasks

    CERN Document Server

    Gwizdka, Jacek

    2010-01-01

    Assessing cognitive load on web search is useful for characterizing search system features and search tasks with respect to their demands on the searcher's mental effort. It is also helpful for examining how individual differences among searchers (e.g. cognitive abilities) affect the search process. We examined cognitive load from the perspective of primary and secondary task performance. A controlled web search study was conducted with 48 participants. The primary task performance components were found to be significantly related to both the objective and the subjective task difficulty. However, the relationship between objective and subjective task difficulty and the secondary task performance measures was weaker than expected. The results indicate that the dual-task approach needs to be used with caution.

  12. The effect of various jaw motor tasks on body sway.

    Science.gov (United States)

    Hellmann, Daniel; Giannakopoulos, N N; Blaser, R; Eberhard, L; Schindler, H J

    2011-10-01

    Alterations of body sway caused by isometric contractions of the jaw muscles have been reported previously. The objective of this study was to test if motor tasks of the masticatory system with different control demands affect body posture differently during quiet stance. Position and sway displacements of the center of foot pressure (COP) were measured for 20 healthy subjects who either kept the mandible at rest or performed unilateral and bilateral maximum voluntary teeth clenching, feedback-controlled biting tasks at submaximum bite forces, or unilateral chewing. Two weeks later the measurements were repeated. Compared with quiet stance, the COP results revealed significant changes during the feedback-controlled biting tasks. Robust sway reduction and anterior displacement of the COP were observed under these conditions. Body oscillations were not significantly affected by maximum bites or by unilateral chewing. For most of the variables investigated there were no significant differences between unilateral and bilateral biting. Robust sway reduction during feedback-controlled biting tasks in healthy subjects involved a stiffening phenomenon that was attributed to the common physiological repertoire of posture control, and might optimize the stability of posture under these conditions. © 2011 Blackwell Publishing Ltd.

  13. Task-specific transfer of perceptual learning across sensory modalities.

    Science.gov (United States)

    McGovern, David P; Astle, Andrew T; Clavin, Sarah L; Newell, Fiona N

    2016-01-11

    It is now widely accepted that primary cortical areas of the brain that were once thought to be sensory-specific undergo significant functional reorganisation following sensory deprivation. For instance, loss of vision or audition leads to the brain areas normally associated with these senses being recruited by the remaining sensory modalities [1]. Despite this, little is known about the rules governing crossmodal plasticity in people who experience typical sensory development, or the potential behavioural consequences. Here, we used a novel perceptual learning paradigm to assess whether the benefits associated with training on a task in one sense transfer to another sense. Participants were randomly assigned to a spatial or temporal task that could be performed visually or aurally, which they practiced for five days; before and after training, we measured discrimination thresholds on all four conditions and calculated the extent of transfer between them. Our results show a clear transfer of learning between sensory modalities; however, generalisation was limited to particular conditions. Specifically, learned improvements on the spatial task transferred from the visual domain to the auditory domain, but not vice versa. Conversely, benefits derived from training on the temporal task transferred from the auditory domain to visual domain, but not vice versa. These results suggest a unidirectional transfer of perceptual learning from dominant to non-dominant sensory modalities and place important constraints on models of multisensory processing and plasticity.

  14. Is a "Complex" Task Really Complex? Validating the Assumption of Cognitive Task Complexity

    Science.gov (United States)

    Sasayama, Shoko

    2016-01-01

    In research on task-based learning and teaching, it has traditionally been assumed that differing degrees of cognitive task complexity can be inferred through task design and/or observations of differing qualities in linguistic production elicited by second language (L2) communication tasks. Without validating this assumption, however, it is…

  15. How to Correct a Task Error: Task-Switch Effects Following Different Types of Error Correction

    Science.gov (United States)

    Steinhauser, Marco

    2010-01-01

    It has been proposed that switch costs in task switching reflect the strengthening of task-related associations and that strengthening is triggered by response execution. The present study tested the hypothesis that only task-related responses are able to trigger strengthening. Effects of task strengthening caused by error corrections were…

  16. Adapting Non-Task-Based Materials to Fit a Task-Based Framework

    Institute of Scientific and Technical Information of China (English)

    郑海英

    2007-01-01

    Analyzes the three -phases--pre -task, task cycle, post -task and their rationale in task -based language teaching, designs corresponding teaching activities after adapting one text from New Horizon College English, so that college English teachers can better understand and use this teaching approach, and then improve the teaching effect and college students'comprehensive application abilities of language.

  17. Is Performance in Task-Cuing Experiments Mediated by Task Set Selection or Associative Compound Retrieval?

    Science.gov (United States)

    Forrest, Charlotte L. D.; Monsell, Stephen; McLaren, Ian P. L.

    2014-01-01

    Task-cuing experiments are usually intended to explore control of task set. But when small stimulus sets are used, they plausibly afford learning of the response associated with a combination of cue and stimulus, without reference to tasks. In 3 experiments we presented the typical trials of a task-cuing experiment: a cue (colored shape) followed,…

  18. The ability to solve methodical tasks as an inner reserve of teacher’s methodical competency

    Directory of Open Access Journals (Sweden)

    Светлана Алексеевна Скворцова

    2016-03-01

    Full Text Available We interprete the teacher's methodical competency as an ability to carry out methodical activity effectively. We present the teacher's methodical activity as solving a number of methodical tasks. Thus, we consider the ability to carry out methodical activity as an ability to solve methodical tasks. We define a methodical task as a situation that occurs in the process of teacher's methodical activity the purpose of which is to teach pupils certain content.Methodical tasks are classified according to the nature of interaction "teacher-pupil" on practical (providing direct interaction "teacher-pupil" and intellectual (not providing direct interaction "teacher-pupil"; according to problematic level - on standard (a teacher possesses ready means of action with methodical objects and problematic (a teacher does not possess any examples of methodical activity and is in a situation of uncertainty. The result of teacher's solving a practical methodical task is teaching pupils certain subject contents; the result of teacher's solving an intellectual task is receiving certain methodical concept, fact or method of operation. Meanwhile, both practical and intellectual methodical tasks may occur either standard or problematic for a teacher. On the basis of an author's classification of methodical tasks on standard, problematic, practical and intellectual we've studied the inner composition of the ability to solve different kinds of methodical tasks such as standard intellectual, standard practical, problematic intellectual and problematic practical tasks. It is clear that the inner composition of these abilities much differs, but, in general, in order to solve any methodical task a teacher must carry out a number of actions: 1 a definition of a situation's goal and the conditions of its achievement: a definition of a task and / or analysis of a task situation; 2 actualization of theoretical information and a known way of solving a task; 3 usage of a known way

  19. Trial-type probability and task-switching effects on behavioral response characteristics in a mixed saccade task.

    Science.gov (United States)

    Pierce, Jordan E; McCardel, J Brett; McDowell, Jennifer E

    2015-03-01

    Eye movement circuitry involved in saccade production offers a model for studying cognitive control: visually guided prosaccades are stimulus-directed responses, while goal-driven antisaccades rely upon more complex control processes to inhibit the prepotent tendency to look toward a cue, transform its spatial location, and generate a volitional saccade in the opposite direction. By manipulating the relative probability of these saccade types, we measured participants' behavioral responses to different levels of implicit trial-type probability and task-switching demands in conditions with relatively long inter-trial fixation and trial-type cue lengths. Results indicated that when prosaccades were less probable in a run, more prosaccade errors were generated; however, for antisaccades, trial-type probability had no effect on the percent of correct responses. For reaction times, specifically in runs with a larger probability of antisaccade trials, latencies increased for both anti- and pro-saccades. Furthermore, task switching resulted in a lower percentage of correct responses on switched trials, but a prior antisaccade trial led to slower reaction times for both trial types (i.e., a task switch cost for prosaccades and switch benefit for antisaccades). These findings indicate that cognitive control demands and residual inhibition from antisaccades alter performance relative to trial-type probability and task switching within a run, with the prosaccade task showing greater susceptibility to the influence of a large probability of cognitively complex antisaccades.

  20. Aging-related decrements during specific phases of the dual-task Timed Up-and-Go test.

    Science.gov (United States)

    Porciuncula, Franchino S; Rao, Ashwini K; McIsaac, Tara L

    2016-02-01

    It is unclear how young and older adults modulate dual-task mobility under changing postural challenges. To examine age-related changes in dual-task processing during specific phases of dual-task Timed Up-and-Go (TUGdual-task). Healthy young and older adults performed the Timed Up-and-Go (TUG) with the following dual-task conditions: (1) serial-three subtractions, (2) carrying cup of water, (3) combined subtraction and carrying water, and (4) dialing cell phone. The primary outcome was the dual-task cost on performance of TUG (percent change from single- to dual-task) based on duration and peak trunk velocity of each phase: (a) straight-walk, (b) sit-to-stand, (c) turn, (d) turn-to-sit. Mixed-design univariate analysis of variance was performed for each type of task. Older adults had more pronounced mobility decrements than young adults during straight-ahead walking and turns when the secondary task engaged both cognitive and manual modalities. Simple cognitive or manual tasks during TUGdual-task did not differentiate young from older participants. Subtraction performance during simple and complex cognitive conditions differed by phase of the TUG. Manual task performance of carrying water did not vary by phase or age. Our findings suggest that dual-task processing is dynamic across phases of TUGdual-task. Aging-related dual-task decrements are demonstrated during straight-ahead walking and turning, particularly when the secondary task is more complex. Older adults are susceptible to reduced dual-task mobility during straight-ahead walking and turning particularly when attentional loading was increased.