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

ERIC Educational Resources Information Center

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…

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

ERIC Educational Resources Information Center

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…

Central cannabinoid receptors modulate acquisition of eyeblink conditioning

PubMed Central

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, particularly the molecular layer, contains a high density of cannabinoid receptors (CB1R). The CB1Rs are located on the axon terminals of parallel fibers, stellate cells, and basket cells where they inhibit neurotransmitter release. The present study examined the effects of a CB1R agonist WIN55,212-2 and antagonist SR141716A on the acquisition of delay eyeblink conditioning in rats. Rats were given subcutaneous administration of 1, 2, or 3 mg/kg of WIN55,212-2 or 1, 3, or 5 mg/kg of SR141716A before each day of acquisition training (10 sessions). Dose-dependent impairments in acquisition were found for WIN55,212-2 and SR141716A, with no effects on spontaneous or nonassociative blinking. However, the magnitude of impairment was greater for WIN55,212-2 than SR141716A. Dose-dependent impairments in conditioned blink response (CR) amplitude and timing were found with WIN55,212-2 but not with SR141716A. The findings support the hypothesis that CB1Rs in the cerebellar cortex play an important role in plasticity mechanisms underlying eyeblink conditioning. PMID:21030483

Temporal Discontiguity Is neither Necessary nor Sufficient for Learning-Induced Effects on Adult Neurogenesis

PubMed Central

Leuner, Benedetta; Waddell, Jaylyn; Gould, Elizabeth; Shors, Tracey J.

2012-01-01

Some, but not all, types of learning and memory can influence neurogenesis in the adult hippocampus. Trace eyeblink conditioning has been shown to enhance the survival of new neurons, whereas delay eyeblink conditioning has no such effect. The key difference between the two training procedures is that the conditioning stimuli are separated in time during trace but not delay conditioning. These findings raise the question of whether temporal discontiguity is necessary for enhancing the survival of new neurons. Here we used two approaches to test this hypothesis. First, we examined the influence of a delay conditioning task in which the duration of the conditioned stimulus (CS) was increased nearly twofold, a procedure that critically engages the hippocampus. Although the CS and unconditioned stimulus are contiguous, this very long delay conditioning procedure increased the number of new neurons that survived. Second, we examined the influence of learning the trace conditioned response (CR) after having acquired the CR during delay conditioning, a procedure that renders trace conditioning hippocampal-independent. In this case, trace conditioning did not enhance the survival of new neurons. Together, these results demonstrate that associative learning increases the survival of new neurons in the adult hippocampus, regardless of temporal contiguity. PMID:17192426

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

PubMed Central

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

Hippocampal theta activity is selectively associated with contingency detection but not discrimination in rabbit discrimination-reversal eyeblink conditioning.

PubMed

Nokia, Miriam S; Wikgren, Jan

2010-04-01

The relative power of the hippocampal theta-band ( approximately 6 Hz) activity (theta ratio) is thought to reflect a distinct neural state and has been shown to affect learning rate in classical eyeblink conditioning in rabbits. We sought to determine if the theta ratio is mostly related to the detection of the contingency between the stimuli used in conditioning or also to the learning of more complex inhibitory associations when a highly demanding delay discrimination-reversal eyeblink conditioning paradigm is used. A high hippocampal theta ratio was not only associated with a fast increase in conditioned responding in general but also correlated with slow emergence of discriminative responding due to sustained responding to the conditioned stimulus not paired with an unconditioned stimulus. The results indicate that the neural state reflected by the hippocampal theta ratio is specifically linked to forming associations between stimuli rather than to the learning of inhibitory associations needed for successful discrimination. This is in line with the view that the hippocampus is responsible for contingency detection in the early phase of learning in eyeblink conditioning. (c) 2009 Wiley-Liss, Inc.

Deficits in hippocampus-mediated Pavlovian conditioning in endogenous hypercortisolism.

PubMed

Grillon, Christian; Smith, Kathryn; Haynos, Ann; Nieman, Lynnette K

2004-12-01

Elevated endogenous levels of corticosteroids cause neural dysfunction and loss, especially within the hippocampus, as well as cognitive impairment in hippocampus-mediated tasks. Because Cushing's syndrome patients suffer from hypercortisolism, they represent a unique opportunity to study the impact of elevated glucocorticoids on cognitive functions. The aim of this study was to examine the performance of Cushing's syndrome patients on trace eyeblink conditioning, a cross-species, hippocampal-mediated test of learning and memory. Eleven Cushing's syndrome patients and 11 healthy control subjects participated in an eyeblink trace conditioning test (1000-msec trace) and a task of declarative memory for words. Salivary cortisol was collected in both the patients and the control subjects, and urinary free cortisol was collected in the patients only. The patients exhibited fewer conditional responses and remembered fewer words, compared with the control subjects. Cortisol levels correlated with immediate and delayed declarative memory only. Conditional response correlated with delayed recall after controlling for the magnitude of unconditional response. The integrity of the hippocampus seems to be compromised in Cushing's syndrome patients. Trace eyeblink conditioning might be useful both as a clinical tool to examine changes in hippocampus function in Cushing's disease patients and as a translational tool of research on the impact of chronic exposure of glucocorticoids.

Impaired delay and trace eyeblink conditioning in school-age children with fetal alcohol syndrome.

PubMed

Jacobson, Sandra W; Stanton, Mark E; Dodge, Neil C; Pienaar, Mariska; Fuller, Douglas S; Molteno, Christopher D; Meintjes, Ernesta M; Hoyme, H Eugene; Robinson, Luther K; Khaole, Nathaniel; Jacobson, Joseph L

2011-02-01

Classical eyeblink conditioning (EBC) involves contingent temporal pairing of a conditioned stimulus (e.g., tone) with an unconditioned stimulus (e.g., air puff). Impairment of EBC has been demonstrated in studies of alcohol-exposed animals and in children exposed prenatally at heavy levels. Fetal alcohol syndrome (FAS) was diagnosed by expert dysmorphologists in a large sample of Cape Coloured, South African children. Delay EBC was examined in a new sample of 63 children at 11.3 years, and trace conditioning in 32 of the same children at 12.8 years. At each age, 2 sessions of 50 trials each were administered on the same day; 2 more sessions the next day, for children not meeting criterion for conditioning. Six of 34 (17.6%) children born to heavy drinkers were diagnosed with FAS, 28 were heavily exposed nonsyndromal (HE), and 29 were nonexposed controls. Only 33.3% with FAS and 42.9% of HE met criterion for delay conditioning, compared with 79.3% of controls. The more difficult trace conditioning task was also highly sensitive to fetal alcohol exposure. Only 16.7% of the FAS and 21.4% of HE met criterion for trace conditioning, compared with 66.7% of controls. The magnitude of the effect of diagnostic group on trace conditioning was not greater than the effect on short delay conditioning, findings consistent with recent rat studies. Longer latency to onset and peak eyeblink CR in exposed children indicated poor timing and failure to blink in anticipation of the puff. Extended training resulted in some but not all of the children reaching criterion. These data showing alcohol-related delay and trace conditioning deficits extend our earlier findings of impaired EBC in 5-year-olds to school-age. Alcohol-related impairment in the cerebellar circuitry required for both forms of conditioning may be sufficient to account for the deficit in both tasks. Extended training was beneficial for some exposed children. EBC provides a well-characterized model system for assessment of degree of cerebellar-related learning and memory dysfunction in fetal alcohol exposed children. Copyright © 2010 by the Research Society on Alcoholism.

Impaired delay and trace eyeblink conditioning in school-age children with fetal alcohol syndrome

PubMed Central

Jacobson, Sandra W.; Stanton, Mark E.; Dodge, Neil C.; Pienaar, Mariska; Fuller, Douglas S.; Molteno, Christopher D.; Meintjes, Ernesta M.; Hoyme, H. Eugene; Robinson, Luther K.; Khaole, Nathaniel; Jacobson, Joseph L.

2013-01-01

Background Classical eyeblink conditioning (EBC) involves contingent temporal pairing of a conditioned stimulus (e.g., tone) with an unconditioned stimulus (e.g., air puff). Impairment of EBC has been demonstrated in studies of alcohol-exposed animals and in children exposed prenatally at heavy levels. Methods Fetal alcohol syndrome (FAS) was diagnosed by expert dysmorphologists in a large sample of Cape Coloured, South African children. Delay EBC was examined in a new sample of 63 children at 11.3 years, and trace conditioning in 32 of the same children at 12.8 years. At each age, two sessions of 50 trials each were administered on the same day; two more sessions the next day, for children not meeting criterion for conditioning. Results 6 of 34 (17.6%) children born to heavy drinkers were diagnosed with FAS, 28 were heavily exposed nonsyndromal (HE), and 29 were non-exposed controls. Only 33.3% with FAS and 42.9% of HE met criterion for delay conditioning, compared with 79.3% of controls. The more difficult trace conditioning task was also highly sensitive to fetal alcohol exposure. Only 16.7% of the FAS and 21.4% of HE met criterion for trace conditioning, compared with 66.7% of controls. The magnitude of the effect of diagnostic group on trace conditioning was not greater than the effect on short delay conditioning, findings consistent with recent rat studies. Longer latency to onset and peak eyeblink CR in exposed children indicated poor timing and failure to blink in anticipation of the puff. Extended training resulted in some but not all of the children reaching criterion. Conclusions These data showing alcohol-related delay and trace conditioning deficits extend our earlier findings of impaired EBC in 5-year-olds to school-age. Alcohol-related impairment in the cerebellar circuitry required for both forms of conditioning may be sufficient to account for the deficit in both tasks. Extended training was beneficial for some exposed children. EBC provides a well-characterized model system for assessment of degree of cerebellar-related learning and memory dysfunction in fetal alcohol exposed children. PMID:21073484

Locomotor activity modulates associative learning in mouse cerebellum.

PubMed

Albergaria, Catarina; Silva, N Tatiana; Pritchett, Dominique L; Carey, Megan R

2018-05-01

Changes in behavioral state can profoundly influence brain function. Here we show that behavioral state modulates performance in delay eyeblink conditioning, a cerebellum-dependent form of associative learning. Increased locomotor speed in head-fixed mice drove earlier onset of learning and trial-by-trial enhancement of learned responses that were dissociable from changes in arousal and independent of sensory modality. Eyelid responses evoked by optogenetic stimulation of mossy fiber inputs to the cerebellum, but not at sites downstream, were positively modulated by ongoing locomotion. Substituting prolonged, low-intensity optogenetic mossy fiber stimulation for locomotion was sufficient to enhance conditioned responses. Our results suggest that locomotor activity modulates delay eyeblink conditioning through increased activation of the mossy fiber pathway within the cerebellum. Taken together, these results provide evidence for a novel role for behavioral state modulation in associative learning and suggest a potential mechanism through which engaging in movement can improve an individual's ability to learn.

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

PubMed Central

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

2014-01-01

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. PMID:24625622

Cerebellar Norepinephrine Modulates Learning of Delay Classical Eyeblink Conditioning: Evidence for Post-Synaptic Signaling via PKA

ERIC Educational Resources Information Center

Fister, Mathew; Bickford, Paula C.; Cartford, M. Claire; Samec, Amy

2004-01-01

The neurotransmitter norepinephrine (NE) has been shown to modulate cerebellar-dependent learning and memory. Lesions of the nucleus locus coeruleus or systemic blockade of noradrenergic receptors has been shown to delay the acquisition of several cerebellar-dependent learning tasks. To date, no studies have shown a direct involvement of…

Dissociating basal forebrain and medial temporal amnesic syndromes: insights from classical conditioning.

PubMed

Myer, Catherine E; Bryant, Deborah; DeLuca, John; Gluck, Mark A

2002-01-01

In humans, anterograde amnesia can result from damage to the medial temporal (MT) lobes (including hippocampus), as well as to other brain areas such as basal forebrain. Results from animal classical conditioning studies suggest that there may be qualitative differences in the memory impairment following MT vs. basal forebrain damage. Specifically, delay eyeblink conditioning is spared after MT damage in animals and humans, but impaired in animals with basal forebrain damage. Recently, we have likewise shown delay eyeblink conditioning impairment in humans with amnesia following anterior communicating artery (ACoA) aneurysm rupture, which damages the basal forebrain. Another associative learning task, a computer-based concurrent visual discrimination, also appears to be spared in MT amnesia while ACoA amnesics are slower to learn the discriminations. Conversely, animal and computational models suggest that, even though MT amnesics may learn quickly, they may learn qualitatively differently from controls, and these differences may result in impaired transfer when familiar information is presented in novel combinations. Our initial data suggests such a two-phase learning and transfer task may provide a double dissociation between MT amnesics (spared initial learning but impaired transfer) and ACoA amnesics (slow initial learning but spared transfer). Together, these emerging data suggest that there are subtle but dissociable differences in the amnesic syndrome following damage to the MT lobes vs. basal forebrain, and that these differences may be most visible in non-declarative tasks such as eyeblink classical conditioning and simple associative learning.

Children with Specific Language Impairment are not impaired in the acquisition and retention of Pavlovian delay and trace conditioning of the eyeblink response☆

PubMed Central

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

2013-01-01

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 7–11 year-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. PMID:24139661

Active Inference and Learning in the Cerebellum.

PubMed

Friston, Karl; Herreros, Ivan

2016-09-01

This letter offers a computational account of Pavlovian conditioning in the cerebellum based on active inference and predictive coding. Using eyeblink conditioning as a canonical paradigm, we formulate a minimal generative model that can account for spontaneous blinking, startle responses, and (delay or trace) conditioning. We then establish the face validity of the model using simulated responses to unconditioned and conditioned stimuli to reproduce the sorts of behavior that are observed empirically. The scheme's anatomical validity is then addressed by associating variables in the predictive coding scheme with nuclei and neuronal populations to match the (extrinsic and intrinsic) connectivity of the cerebellar (eyeblink conditioning) system. Finally, we try to establish predictive validity by reproducing selective failures of delay conditioning, trace conditioning, and extinction using (simulated and reversible) focal lesions. Although rather metaphorical, the ensuing scheme can account for a remarkable range of anatomical and neurophysiological aspects of cerebellar circuitry-and the specificity of lesion-deficit mappings that have been established experimentally. From a computational perspective, this work shows how conditioning or learning can be formulated in terms of minimizing variational free energy (or maximizing Bayesian model evidence) using exactly the same principles that underlie predictive coding in perception.

Transcriptional profiling reveals regulated genes in the hippocampus during memory formation

NASA Technical Reports Server (NTRS)

Donahue, Christine P.; Jensen, Roderick V.; Ochiishi, Tomoyo; Eisenstein, Ingrid; Zhao, Mingrui; Shors, Tracey; Kosik, Kenneth S.

2002-01-01

Transcriptional profiling (TP) offers a powerful approach to identify genes activated during memory formation and, by inference, the molecular pathways involved. Trace eyeblink conditioning is well suited for the study of regional gene expression because it requires the hippocampus, whereas the highly parallel task, delay conditioning, does not. First, we determined when gene expression was most regulated during trace conditioning. Rats were exposed to 200 trials per day of paired and unpaired stimuli each day for 4 days. Changes in gene expression were most apparent 24 h after exposure to 200 trials. Therefore, we profiled gene expression in the hippocampus 24 h after 200 trials of trace eyeblink conditioning, on multiple arrays using additional animals. Of 1,186 genes on the filter array, seven genes met the statistical criteria and were also validated by real-time polymerase chain reaction. These genes were growth hormone (GH), c-kit receptor tyrosine kinase (c-kit), glutamate receptor, metabotropic 5 (mGluR5), nerve growth factor-beta (NGF-beta), Jun oncogene (c-Jun), transmembrane receptor Unc5H1 (UNC5H1), and transmembrane receptor Unc5H2 (UNC5H2). All these genes, except for GH, were downregulated in response to trace conditioning. GH was upregulated; therefore, we also validated the downregulation of the GH inhibitor, somatostatin (SST), even though it just failed to meet criteria on the arrays. By during situ hybridization, GH was expressed throughout the cell layers of the hippocampus in response to trace conditioning. None of the genes regulated in trace eyeblink conditioning were similarly affected by delay conditioning, a task that does not require the hippocampus. These findings demonstrate that transcriptional profiling can exhibit a repertoire of genes sensitive to the formation of hippocampal-dependent associative memories.

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

PubMed

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. Copyright © 2013 Elsevier B.V. All rights reserved.

Eye-blink conditioning deficits indicate temporal processing abnormalities in schizophrenia.

PubMed

Bolbecker, Amanda R; Mehta, Crystal S; Edwards, Chad R; Steinmetz, Joseph E; O'Donnell, Brian F; Hetrick, William P

2009-06-01

Theoretical models suggest that symptoms of schizophrenia may be due to a dysfunctional modulatory system associated with the cerebellum. Although it has long been known that the cerebellum plays a critical role in associative learning and motor timing, recent evidence suggests that it also plays a role in nonmotor psychological processes. Indeed, cerebellar anomalies in schizophrenia have been linked to cognitive dysfunction and poor long-term outcome. To test the hypothesis that schizophrenia is associated with cerebellar dysfunction, cerebellar-dependent, delay eye-blink conditioning was examined in 62 individuals with schizophrenia and 62 age-matched non-psychiatric comparison subjects. The conditioned stimulus was a 400 ms tone, which co-terminated with a 50 ms unconditioned stimulus air puff. A subset of participants (25 with schizophrenia and 29 controls) also completed the Wechsler Abbreviated Scale of Intelligence. Participants with schizophrenia exhibited lower rates of eye-blink conditioning, including earlier (less adaptively timed) conditioned response latencies. Cognitive functioning was correlated with the rate of conditioned responsing in the non-psychiatric comparison subjects but not among those with schizophrenia, and the magnitude of these correlations significantly differed between groups. These findings are consistent with models of schizophrenia in which disruptions within the cortico-cerebellar-thalamic-cortical (CCTC) brain circuit are postulated to underlie the cognitive fragmentation that characterizes the disorder.

Eye-Blink Conditioning Deficits Indicate Temporal Processing Abnormalities in Schizophrenia

PubMed Central

Bolbecker, Amanda R.; Mehta, Crystal; Edwards, Chad R.; Steinmetz, Joseph E.; O’Donnell, Brian F.; Hetrick, William P.

2009-01-01

Theoretical models suggest that symptoms of schizophrenia may be due to a dysfunctional modulatory system associated with the cerebellum. Although it has long been known that the cerebellum plays a critical role in associative learning and motor timing, recent evidence suggests that it also plays a role in nonmotor psychological processes. Indeed, cerebellar anomalies in schizophrenia have been linked to cognitive dysfunction and poor long-term outcome. To test the hypothesis that schizophrenia is associated with cerebellar dysfunction, cerebellar-dependent, delay eye-blink conditioning was examined in 62 individuals with schizophrenia and 62 age-matched non-psychiatric comparison subjects. The conditioned stimulus was a 400 ms tone, which co-terminated with a 50 ms unconditioned stimulus air puff. A subset of participants (25 with schizophrenia and 29 controls) also completed the Wechsler Abbreviated Scale of Intelligence. Participants with schizophrenia exhibited lower rates of eye-blink conditioning, including earlier (less adaptively timed) conditioned response latencies. Cognitive functioning was correlated with the rate of conditioned responsing in the non-psychiatric comparison subjects but not among those with schizophrenia, and the magnitude of these correlations significantly differed between groups. These findings are consistent with models of schizophrenia in which disruptions within the cortico-cerebellar-thalamic-cortical (CCTC) brain circuit are postulated to underlie the cognitive fragmentation that characterizes the disorder. PMID:19351577

Cerebellar learning mechanisms

PubMed Central

Freeman, John H.

2014-01-01

The mechanisms underlying cerebellar learning are reviewed with an emphasis on old arguments and new perspectives on eyeblink conditioning. Eyeblink conditioning has been used for decades a model system for elucidating cerebellar learning mechanisms. The standard model of the mechanisms underlying eyeblink conditioning is that there two synaptic plasticity processes within the cerebellum that are necessary for acquisition of the conditioned response: 1) long-term depression (LTD) at parallel fiber-Purkinje cell synapses and 2) long-term potentiation (LTP) at mossy fiber-interpositus nucleus synapses. Additional Purkinje cell plasticity mechanisms may also contribute to eyeblink conditioning including LTP, excitability, and entrainment of deep nucleus activity. Recent analyses of the sensory input pathways necessary for eyeblink conditioning indicate that the cerebellum regulates its inputs to facilitate learning and maintain plasticity. Cerebellar learning during eyeblink conditioning is therefore a dynamic interactive process which maximizes responding to significant stimuli and suppresses responding to irrelevant or redundant stimuli. PMID:25289586

Behaviorally-inhibited temperament is associated with severity of PTSD symptoms and faster eyeblink conditioning in veterans

PubMed Central

Myers, Catherine E.; VanMeenen, Kirsten M.; McAuley, J. Devin; Beck, Kevin D.; Pang, Kevin C. H.; Servatius, Richard J.

2012-01-01

Prior studies have sometimes demonstrated facilitated acquisition of classically-conditioned responses and/or resistance to extinction in post-traumatic stress disorder (PTSD). However, it is unclear whether these behaviors are acquired as a result of PTSD or exposure to trauma, or reflect pre-existing risk factors that confer vulnerability for PTSD. Here, we examined classical eyeblink conditioning and extinction in veterans self-assessed for current PTSD symptoms, exposure to combat, and the personality trait of behavioral inhibition (BI), a risk factor for PTSD. 128 veterans were recruited (mean age 51.2 years; 13.3% female); 126 completed self-assessment, with 25.4% reporting a history of exposure to combat and 30.9% reporting severe, current PTSD symptoms (PTSS). PTSD symptom severity was correlated with current BI (R2=0.497) and PTSS status could be predicted based on current BI and combat history (80.2% correct classification). A subset of the veterans (n=87) also completed eyeblink conditioning. Among veterans without PTSS, childhood BI was associated with faster acquisition; veterans with PTSS showed delayed extinction, under some conditions. These data demonstrate a relationship between current BI and PTSS, and suggest that the facilitated conditioning sometimes observed in PTSD patients may partially reflect personality traits such as childhood BI that pre-date and contribute to vulnerability for PTSD. PMID:21790343

Neonatal ethanol exposure results in dose-dependent impairments in the acquisition and timing of the conditioned eyeblink response and altered cerebellar interpositus nucleus and hippocampal CA1 unit activity in adult rats.

PubMed

Lindquist, Derick H; Sokoloff, Greta; Milner, Eric; Steinmetz, Joseph E

2013-09-01

Exposure to ethanol in neonatal rats results in reduced neuronal numbers in the cerebellar cortex and deep nuclei of juvenile and adult animals. This reduction in cell numbers is correlated with impaired delay eyeblink conditioning (EBC), a simple motor learning task in which a neutral conditioned stimulus (CS; tone) is repeatedly paired with a co-terminating unconditioned stimulus (US; periorbital shock). Across training, cell populations in the interpositus (IP) nucleus model the temporal form of the eyeblink-conditioned response (CR). The hippocampus, though not required for delay EBC, also shows learning-dependent increases in CA1 and CA3 unit activity. In the present study, rat pups were exposed to 0, 3, 4, or 5 mg/kg/day of ethanol during postnatal days (PD) 4-9. As adults, CR acquisition and timing were assessed during 6 training sessions of delay EBC with a short (280 ms) interstimulus interval (ISI; time from CS onset to US onset) followed by another 6 sessions with a long (880 ms) ISI. Neuronal activity was recorded in the IP and area CA1 during all 12 sessions. The high-dose rats learned the most slowly and, with the moderate-dose rats, produced the longest CR peak latencies over training to the short ISI. The low dose of alcohol impaired CR performance to the long ISI only. The 3E (3 mg/kg/day of ethanol) and 5E (5 mg/kg/day of ethanol) rats also showed slower-than-normal increases in learning-dependent excitatory unit activity in the IP and CA1. The 4E (4 mg/kg/day of ethanol) rats showed a higher rate of CR production to the long ISI and enhanced IP and CA1 activation when compared to the 3E and 5E rats. The results indicate that binge-like ethanol exposure in neonatal rats induces long-lasting, dose-dependent deficits in CR acquisition and timing and diminishes conditioning-related neuronal excitation in both the cerebellum and hippocampus. Published by Elsevier Inc.

Neonatal ethanol exposure results in dose-dependent impairments in the acquisition and timing of the conditioned eyeblink response and altered cerebellar interpositus nucleus and hippocampal CA1 unit activity in adult rats

PubMed Central

Lindquist, Derick H.; Sokoloff, Greta; Milner, Eric; Steinmetz, Joseph E.

2013-01-01

Exposure to ethanol in neonatal rats results in reduced neuronal numbers in the cerebellar cortex and deep nuclei of juvenile and adult animals. This reduction in cell numbers is correlated with impaired delay eyeblink conditioning (EBC), a simple motor learning task in which a neutral conditioned stimulus (CS; tone) is repeatedly paired with a co-terminating unconditioned stimulus (US; periorbital shock). Across training, cell populations in the interpositus (IP) nucleus model the temporal form of the eyeblink conditioned response (CR). The hippocampus, though not required for delay EBC, also shows learning-dependent increases in CA1 and CA3 unit activity. In the present study, rat pups were exposed to 0, 3, 4, or 5 mg/kg/day of ethanol during postnatal days (PD) 4–9. As adults, CR acquisition and timing were assessed during 6 training sessions of delay EBC with a short (280 msec) interstimulus interval (ISI; time from CS onset to US onset) followed by another 6 sessions with a long (880 msec) ISI. Neuronal activity was recorded in the IP and area CA1 during all 12 sessions. The high-dose rats learned the most slowly and, with the moderate-dose rats, produced the longest CR peak latencies over training to the short ISI. The low dose of alcohol impaired CR performance to the long ISI only. The 3E (3 mg/kg/day of ethanol) and 5E (5 mg/kg/day of ethanol) rats also showed slower-than-normal increases in learning-dependent excitatory unit activity in the IP and CA1. The 4E (4 mg/kg/day of ethanol) rats showed a higher rate of CR production to the long ISI and enhanced IP and CA1 activation when compared to the 3E and 5E rats. The results indicate that binge-like ethanol exposure in neonatal rats induces long-lasting, dose-dependent deficits in CR acquisition and timing and diminishes conditioning-related neuronal excitation in both the cerebellum and hippocampus. PMID:23871534

Disruption of trace conditioning of the nictitating membrane response in rabbits by central cholinergic blockade.

PubMed

Kaneko, T; Thompson, R F

1997-05-01

Central muscarinic cholinergic involvement in classical conditioning of eyeblink responses was determined in trace and delay paradigms. Rabbits were trained on a trace procedure in which a 250-ms tone conditioned stimulus (CS) and a 100-ms air-puff unconditioned stimulus (UCS) were presented with a 500-ms trace interval. Each training session day consisted of ten tone alone, ten air-puff alone and 80 paired CS-UCS trials. Scopolamine hydrochloride at doses of 0.03 and 0.1 mg/0.5 ml per kg, s.c. dose-dependently disrupted acquisition of conditioned responses. Rabbits that were treated with scopolamine and failed to learn showed a gradual increase in conditioned responses during an additional training period with saline injections and no transfer from earlier training. Scopolamine methyl bromide, which does not appreciably cross the blood-brain barrier, showed no effects in the trace conditioning paradigm at a dose of 0.1 mg/kg, s.c., indicating central cholinergic blockade is responsible for the suppressive effect of scopolamine. Scopolamine hydrochloride at a dose of 0.1 mg/kg, s.c. did not block acquisition in the delay procedure with a 250-ms inter-stimulus interval, although the rate of acquisition was somewhat reduced by the drug. These data are the first to demonstrate that classical conditioning of the eyeblink response in the trace procedure is highly sensitive to central cholinergic deficits.

Memory consolidation within the central amygdala is not necessary for modulation of cerebellar learning.

PubMed

Steinmetz, Adam B; Ng, Ka H; Freeman, John H

2017-06-01

Amygdala lesions impair, but do not prevent, acquisition of cerebellum-dependent eyeblink conditioning suggesting that the amygdala modulates cerebellar learning. Two-factor theories of eyeblink conditioning posit that a fast-developing memory within the amygdala facilitates slower-developing memory within the cerebellum. The current study tested this hypothesis by impairing memory consolidation within the amygdala with inhibition of protein synthesis, transcription, and NMDA receptors in rats. Rats given infusions of anisomycin or DRB into the central amygdala (CeA) immediately after each eyeblink conditioning session were severely impaired in contextual and cued fear conditioning, but were completely unimpaired in eyeblink conditioning. Rats given the NMDA antagonist ifenprodil into the CeA before each eyeblink conditioning session also showed impaired fear conditioning, but no deficit in eyeblink conditioning. The results indicate that memory formation within the CeA is not necessary for its modulation of cerebellar learning mechanisms. The CeA may modulate cerebellar learning and retention through an attentional mechanism that develops within the training sessions. © 2017 Steinmetz et al.; Published by Cold Spring Harbor Laboratory Press.

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

ERIC Educational Resources Information Center

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…

Is Perruchet's dissociation between eyeblink conditioned responding and outcome expectancy evidence for two learning systems?

PubMed

Weidemann, Gabrielle; Tangen, Jason M; Lovibond, Peter F; Mitchell, Christopher J

2009-04-01

P. Perruchet (1985b) showed a double dissociation of conditioned responses (CRs) and expectancy for an airpuff unconditioned stimulus (US) in a 50% partial reinforcement schedule in human eyeblink conditioning. In the Perruchet effect, participants show an increase in CRs and a concurrent decrease in expectancy for the airpuff across runs of reinforced trials; conversely, participants show a decrease in CRs and a concurrent increase in expectancy for the airpuff across runs of nonreinforced trials. Three eyeblink conditioning experiments investigated whether the linear trend in eyeblink CRs in the Perruchet effect is a result of changes in associative strength of the conditioned stimulus (CS), US sensitization, or learning the precise timing of the US. Experiments 1 and 2 demonstrated that the linear trend in eyeblink CRs is not the result of US sensitization. Experiment 3 showed that the linear trend in eyeblink CRs is present with both a fixed and a variable CS-US interval and so is not the result of learning the precise timing of the US. The results are difficult to reconcile with a single learning process model of associative learning in which expectancy mediates CRs. Copyright (c) 2009 APA, all rights reserved.

Cerebellar Structure and Function in Male Wistar-Kyoto Hyperactive Rats

PubMed Central

Thanellou, Alexandra; Green, John T.

2014-01-01

Previous research has suggested that the Wistar-Kyoto Hyperactive (WKHA) rat strain may model some of the behavioral features associated with attention-deficit/hyperactivity disorder (ADHD). We have shown that, in cerebellar-dependent eyeblink conditioning, WKHA emit eyeblink CRs with shortened onset latencies. To further characterize the shortened CR onset latencies seen in WKHA rats, we examined 750-ms delay conditioning with either a tone CS or a light CS, we extended acquisition training, and we included Wistar rats as an additional, outbred control strain. Our results indicated that WKHAs learned more quickly and showed a shortened CR onset latency to a tone CS compared to both Wistar-Kyoto Hypertensive (WKHT) and Wistars. WKHAs and Wistars show a lengthening of CR onset latency over conditioning with a tone CS and an increasing confinement of CRs to the later part of the tone CS (inhibition of delay). WKHAs learned more quickly to a light CS only in comparison to WKHTs and showed a shortened CR onset latency only in comparison to Wistars. Wistars showed an increasing confinement of CRs to the late part of the light CS over conditioning. We used unbiased stereology to estimate the number of Purkinje and granule cells in the cerebellar cortex of the three strains. Our results indicated that WKHAs have more granule cells than Wistars and WKHTs and more Purkinje cells than Wistars. Results are discussed in terms of CS processing and cerebellar cortical contributions to EBC. PMID:23398437

Modulation of 7 T fMRI Signal in the Cerebellar Cortex and Nuclei During Acquisition, Extinction, and Reacquisition of Conditioned Eyeblink Responses.

PubMed

Ernst, Thomas M; Thürling, Markus; Müller, Sarah; Kahl, Fabian; Maderwald, Stefan; Schlamann, Marc; Boele, Henk-Jan; Koekkoek, Sebastiaan K E; Diedrichsen, Jörn; De Zeeuw, Chris I; Ladd, Mark E; Timmann, Dagmar

2017-08-01

Classical delay eyeblink conditioning is likely the most commonly used paradigm to study cerebellar learning. As yet, few studies have focused on extinction and savings of conditioned eyeblink responses (CRs). Saving effects, which are reflected in a reacquisition after extinction that is faster than the initial acquisition, suggest that learned associations are at least partly preserved during extinction. In this study, we tested the hypothesis that acquisition-related plasticity is nihilated during extinction in the cerebellar cortex, but retained in the cerebellar nuclei, allowing for faster reacquisition. Changes of 7 T functional magnetic resonance imaging (fMRI) signals were investigated in the cerebellar cortex and nuclei of young and healthy human subjects. Main effects of acquisition, extinction, and reacquisition against rest were calculated in conditioned stimulus-only trials. First-level β values were determined for a spherical region of interest (ROI) around the acquisition peak voxel in lobule VI, and dentate and interposed nuclei ipsilateral to the unconditioned stimulus. In the cerebellar cortex and nuclei, fMRI signals were significantly lower in extinction compared to acquisition and reacquisition, but not significantly different between acquisition and reacquisition. These findings are consistent with the theory of bidirectional learning in both the cerebellar cortex and nuclei. It cannot explain, however, why conditioned responses reappear almost immediately in reacquisition following extinction. Although the present data do not exclude that part of the initial memory remains in the cerebellum in extinction, future studies should also explore changes in extracerebellar regions as a potential substrate of saving effects. Hum Brain Mapp 38:3957-3974, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Real-time cerebellar neuroprosthetic system based on a spiking neural network model of motor learning.

PubMed

Xu, Tao; Xiao, Na; Zhai, Xiaolong; Kwan Chan, Pak; Tin, Chung

2018-02-01

Damage to the brain, as a result of various medical conditions, impacts the everyday life of patients and there is still no complete cure to neurological disorders. Neuroprostheses that can functionally replace the damaged neural circuit have recently emerged as a possible solution to these problems. Here we describe the development of a real-time cerebellar neuroprosthetic system to substitute neural function in cerebellar circuitry for learning delay eyeblink conditioning (DEC). The system was empowered by a biologically realistic spiking neural network (SNN) model of the cerebellar neural circuit, which considers the neuronal population and anatomical connectivity of the network. The model simulated synaptic plasticity critical for learning DEC. This SNN model was carefully implemented on a field programmable gate array (FPGA) platform for real-time simulation. This hardware system was interfaced in in vivo experiments with anesthetized rats and it used neural spikes recorded online from the animal to learn and trigger conditioned eyeblink in the animal during training. This rat-FPGA hybrid system was able to process neuronal spikes in real-time with an embedded cerebellum model of ~10 000 neurons and reproduce learning of DEC with different inter-stimulus intervals. Our results validated that the system performance is physiologically relevant at both the neural (firing pattern) and behavioral (eyeblink pattern) levels. This integrated system provides the sufficient computation power for mimicking the cerebellar circuit in real-time. The system interacts with the biological system naturally at the spike level and can be generalized for including other neural components (neuron types and plasticity) and neural functions for potential neuroprosthetic applications.

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

PubMed Central

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

Eyeblink Conditioning in Healthy Adults: A Positron Emission Tomography Study

PubMed Central

Andreasen, Nancy C.; Liu, Dawei; Freeman, John H.; Boles Ponto, Laura L.; O’Leary, Daniel S.

2013-01-01

Eyeblink conditioning is a paradigm commonly used to investigate the neural mechanisms underlying motor learning. It involves the paired presentation of a toneconditioning stimulus which precedes and co-terminates with an airpuff unconditioned stimulus. Following repeated paired presentations a conditioned eyeblink develops which precedes the airpuff. This type of learning has been intensively studied and the cerebellum is known to be essential in both humans and animals. The study presented here was designed to investigate the role of the cerebellum during eyeblink conditioning in humans using positron emission tomography (PET). The sample includes 20 subjects (10 male and 10 female) with an average age of 29.2 years. PET imaging was used to measure regional cerebral blood flow (rCBF) changes occurring during the first, second, and third blocks of conditioning. In addition, stimuli-specific rCBF to unpaired tones and airpuffs (“pseudoconditioning”) was used as a baseline level that was subtracted from each block. Conditioning was performed using three, 15-trial blocks of classical eyeblink conditioning with the last five trials in each block imaged. As expected, subjects quickly acquired conditioned responses. A comparison between the conditioning tasks and the baseline task revealed that during learning there was activation of the cerebellum and recruitment of several higher cortical regions. Specifically, large peaks were noted in cerebellar lobules IV/V, the frontal lobes, and cingulate gyri. PMID:22430943

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

PubMed Central

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

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

PubMed

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.

Voluntary eyeblinks disrupt iconic memory.

PubMed

Thomas, Laura E; Irwin, David E

2006-04-01

In the present research, we investigated whether eyeblinks interfere with cognitive processing. In Experiment 1, the participants performed a partial-report iconic memory task in which a letter array was presented for 106 msec, followed 50, 150, or 750 msec later by a tone that cued recall of onerow of the array. At a cue delay of 50 msec between array offset and cue onset, letter report accuracy was lower when the participants blinked following array presentation than under no-blink conditions; the participants made more mislocation errors under blink conditions. This result suggests that blinking interferes with the binding of object identity and object position in iconic memory. Experiment 2 demonstrated that interference due to blinks was not due merely to changes in light intensity. Experiments 3 and 4 demonstrated that other motor responses did not interfere with iconic memory. We propose a new phenomenon, cognitive blink suppression, in which blinking inhibits cognitive processing. This phenomenon may be due to neural interference. Blinks reduce activation in area V1, which may interfere with the representation of information in iconic memory.

Medial Auditory Thalamic Stimulation as a Conditioned Stimulus for Eyeblink Conditioning in Rats

ERIC Educational Resources Information Center

Campolattaro, Matthew M.; Halverson, Hunter E.; Freeman, John H.

2007-01-01

The neural pathways that convey conditioned stimulus (CS) information to the cerebellum during eyeblink conditioning have not been fully delineated. It is well established that pontine mossy fiber inputs to the cerebellum convey CS-related stimulation for different sensory modalities (e.g., auditory, visual, tactile). Less is known about the…

Autism and Classical Eyeblink Conditioning: Performance Changes of the Conditioned Response Related to Autism Spectrum Disorder Diagnosis

PubMed Central

Welsh, John P.; Oristaglio, Jeffrey T.

2016-01-01

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 (Asp/PDD) not otherwise specified and compared to an age- and IQ-matched group of children who 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. Both AD and Asp/PDD 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 between diagnostic groups, and this may indicate that EBC performance can report the heterogeneity in the neurobiological predispositions for ASD. The findings will inform further explorations with larger cohorts, different sensory modalities, and different EBC paradigms and provide a reference set for future EBC studies of children having ASD and non-human models. PMID:27563293

Lack of renewal effect in extinction of naturally acquired conditioned eyeblink responses, but possible dependency on physical context.

PubMed

Claassen, J; Mazilescu, L; Thieme, A; Bracha, V; Timmann, D

2016-01-01

Context dependency of extinction is well known and has extensively been studied in fear conditioning, but has rarely been assessed in eyeblink conditioning. One way to demonstrate context dependency of extinction is the renewal effect. ABA paradigms are most commonly used to show the renewal effect of extinguished learned fear: if acquisition takes place in context A, and extinction takes place in context B (extinction phase), learned responses will recover in subsequent extinction trials presented in context A (renewal phase). The renewal effect of the visual threat eyeblink response (VTER), a conditioned eyeblink response, which is naturally acquired in early infancy, was examined in a total of 48 young and healthy participants with two experiments using an ABA paradigm. Twenty paired trials were performed in context A (baseline trials), followed by 50 extinction trials in context B (extinction phase) and 50 extinction trials in context A (renewal phase). In 24 participants, contexts A and B were two different rooms, and in the other 24 participants, two different background colors (orange and blue) and noises were used. To rule out spontaneous recovery, an AAA design was used for comparison. There were significant effects of extinction in both experiments. No significant renewal effects were observed. In experiment 2, however, extinction was significantly less using orange background during extinction compared to the blue background. The present findings suggest that extinction of conditioned eyeblinks depends on the physical context. Findings add to the animal literature that context can play a role in the acquisition of classically conditioned eyeblink responses. Future studies, however, need to be performed to confirm the present findings. Lack of renewal effect may be explained by the highly overlearned character of the VTER.

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

ERIC Educational Resources Information Center

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…

Real-time cerebellar neuroprosthetic system based on a spiking neural network model of motor learning

NASA Astrophysics Data System (ADS)

Xu, Tao; Xiao, Na; Zhai, Xiaolong; Chan, Pak Kwan; Tin, Chung

2018-02-01

Objective. Damage to the brain, as a result of various medical conditions, impacts the everyday life of patients and there is still no complete cure to neurological disorders. Neuroprostheses that can functionally replace the damaged neural circuit have recently emerged as a possible solution to these problems. Here we describe the development of a real-time cerebellar neuroprosthetic system to substitute neural function in cerebellar circuitry for learning delay eyeblink conditioning (DEC). Approach. The system was empowered by a biologically realistic spiking neural network (SNN) model of the cerebellar neural circuit, which considers the neuronal population and anatomical connectivity of the network. The model simulated synaptic plasticity critical for learning DEC. This SNN model was carefully implemented on a field programmable gate array (FPGA) platform for real-time simulation. This hardware system was interfaced in in vivo experiments with anesthetized rats and it used neural spikes recorded online from the animal to learn and trigger conditioned eyeblink in the animal during training. Main results. This rat-FPGA hybrid system was able to process neuronal spikes in real-time with an embedded cerebellum model of ~10 000 neurons and reproduce learning of DEC with different inter-stimulus intervals. Our results validated that the system performance is physiologically relevant at both the neural (firing pattern) and behavioral (eyeblink pattern) levels. Significance. This integrated system provides the sufficient computation power for mimicking the cerebellar circuit in real-time. The system interacts with the biological system naturally at the spike level and can be generalized for including other neural components (neuron types and plasticity) and neural functions for potential neuroprosthetic applications.

Eye-Blink Conditioning Is Associated with Changes in Synaptic Ultrastructure in the Rabbit Interpositus Nuclei

ERIC Educational Resources Information Center

Weeks, Andrew C. W.; Connor, Steve; Hinchcliff, Richard; LeBoutillier, Janelle C.; Thompson, Richard F.; Petit, Ted L.

2007-01-01

Eye-blink conditioning involves the pairing of a conditioned stimulus (usually a tone) to an unconditioned stimulus (air puff), and it is well established that an intact cerebellum and interpositus nucleus, in particular, are required for this form of classical conditioning. Changes in synaptic number or structure have long been proposed as a…

Blocking the BK Channel Impedes Acquisition of Trace Eyeblink Conditioning

ERIC Educational Resources Information Center

Matthews, Elizabeth A.; Disterhoft, John F.

2009-01-01

Big-K[superscript +] conductance (BK)-channel mediated fast afterhyperpolarizations (AHPs) following action potentials are reduced after eyeblink conditioning. Blocking BK channels with paxilline increases evoked firing frequency in vitro and spontaneous pyramidal activity in vivo. To examine how increased excitability after BK-channel blockade…

Effects of systemic glutamatergic manipulations on conditioned eyeblink responses and hyperarousal in a rabbit model of post-traumatic stress disorder.

PubMed

Burhans, Lauren B; Smith-Bell, Carrie A; Schreurs, Bernard G

2017-10-01

Glutamatergic dysfunction is implicated in many neuropsychiatric conditions, including post-traumatic stress disorder (PTSD). Glutamate antagonists have shown some utility in treating PTSD symptoms, whereas glutamate agonists may facilitate cognitive behavioral therapy outcomes. We have developed an animal model of PTSD, based on conditioning of the rabbit's eyeblink response, that addresses two key features: conditioned responses (CRs) to cues associated with an aversive event and a form of conditioned hyperarousal referred to as conditioning-specific reflex modification (CRM). The optimal treatment to reduce both CRs and CRM is unpaired extinction. The goals of the study were to examine whether treatment with the N-methyl-D-aspartate glutamate receptor antagonist ketamine could reduce CRs and CRM, and whether the N-methyl-D-aspartate agonist D-cycloserine combined with unpaired extinction treatment could enhance the extinction of both. Administration of a single dose of subanesthetic ketamine had no significant immediate or delayed effect on CRs or CRM. Combining D-cycloserine with a single day of unpaired extinction facilitated extinction of CRs in the short term while having no impact on CRM. These results caution that treatments may improve one aspect of the PTSD symptomology while having no significant effects on other symptoms, stressing the importance of a multiple-treatment approach to PTSD and of animal models that address multiple symptoms.

Eyeblink Conditioning: A Non-Invasive Biomarker for Neurodevelopmental Disorders

ERIC Educational Resources Information Center

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,…

EYEBLINK CONDITIONING IN THE INFANT RAT: AN ANIMAL MODEL OF LEARNING IN DEVELOPMENTAL NEUROTOXICOLOGY

EPA Science Inventory

Classical conditioning of the eyeblink reflex is a relatively simple procedure for studying associative learning that was first developed for use with human subjects more than half a century ago. The use of this procedure in laboratory animals by psychologists and neuro-scientist...

Inferior Colliculus Lesions Impair Eyeblink Conditioning in Rats

ERIC Educational Resources Information Center

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

2007-01-01

The neural plasticity necessary for acquisition and retention of eyeblink conditioning has been localized to the cerebellum. However, the sources of sensory input to the cerebellum that are necessary for establishing learning-related plasticity have not been identified completely. The inferior colliculus may be a source of sensory input to the…

Cerebellar Secretin Modulates Eyeblink Classical Conditioning

ERIC Educational Resources Information Center

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…

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

ERIC Educational Resources Information Center

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…

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

ERIC Educational Resources Information Center

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…

Memory Consolidation within the Central Amygdala Is Not Necessary for Modulation of Cerebellar Learning

ERIC Educational Resources Information Center

Steinmetz, Adam B.; Ng, Ka H.; Freeman, John H.

2017-01-01

Amygdala lesions impair, but do not prevent, acquisition of cerebellum-dependent eyeblink conditioning suggesting that the amygdala modulates cerebellar learning. Two-factor theories of eyeblink conditioning posit that a fast-developing memory within the amygdala facilitates slower-developing memory within the cerebellum. The current study tested…

Changes in complex spike activity during classical conditioning

PubMed Central

Rasmussen, Anders; Jirenhed, Dan-Anders; Wetmore, Daniel Z.; Hesslow, Germund

2014-01-01

The cerebellar cortex is necessary for adaptively timed conditioned responses (CRs) in eyeblink conditioning. During conditioning, Purkinje cells acquire pause responses or “Purkinje cell CRs” to the conditioned stimuli (CS), resulting in disinhibition of the cerebellar nuclei (CN), allowing them to activate motor nuclei that control eyeblinks. This disinhibition also causes inhibition of the inferior olive (IO), via the nucleo-olivary pathway (N-O). Activation of the IO, which relays the unconditional stimulus (US) to the cortex, elicits characteristic complex spikes in Purkinje cells. Although Purkinje cell activity, as well as stimulation of the CN, is known to influence IO activity, much remains to be learned about the way that learned changes in simple spike firing affects the IO. In the present study, we analyzed changes in simple and complex spike firing, in extracellular Purkinje cell records, from the C3 zone, in decerebrate ferrets undergoing training in a conditioning paradigm. In agreement with the N-O feedback hypothesis, acquisition resulted in a gradual decrease in complex spike activity during the conditioned stimulus, with a delay that is consistent with the long N-O latency. Also supporting the feedback hypothesis, training with a short interstimulus interval (ISI), which does not lead to acquisition of a Purkinje cell CR, did not cause a suppression of complex spike activity. In contrast, observations that extinction did not lead to a recovery in complex spike activity and the irregular patterns of simple and complex spike activity after the conditioned stimulus are less conclusive. PMID:25140129

Evidence of plasticity in the pontocerebellar conditioned stimulus pathway during classical conditioning of the eyeblink response in the rabbit.

PubMed

Tracy, Jo Anne; Thompson, Judith K; Krupa, David J; Thompson, Richard F

2013-10-01

Electrical stimulation thresholds required to elicit eyeblinks with either pontine or cerebellar interpositus stimulation were measured before and after classical eyeblink conditioning with paired pontine stimulation (conditioned stimulus, CS) and corneal airpuff (unconditioned stimulus, US). Pontine stimulation thresholds dropped dramatically after training and returned to baseline levels following extinction, whereas interpositus thresholds and input-output functions remained stable across training sessions. Learning rate, magnitude of threshold change, and electrode placements were correlated. Pontine projection patterns to the cerebellum were confirmed with retrograde labeling techniques. These results add to the body of literature suggesting that the pons relays CS information to the cerebellum and provide further evidence of synaptic plasticity in the cerebellar network. 2013 APA, all rights reserved

Training-Dependent Associative Learning Induced Neocortical Structural Plasticity: A Trace Eyeblink Conditioning Analysis

PubMed Central

Chau, Lily S.; Prakapenka, Alesia V.; Zendeli, Liridon; Davis, Ashley S.; Galvez, Roberto

2014-01-01

Studies utilizing general learning and memory tasks have suggested the importance of neocortical structural plasticity for memory consolidation. However, these learning tasks typically result in learning of multiple different tasks over several days of training, making it difficult to determine the synaptic time course mediating each learning event. The current study used trace-eyeblink conditioning to determine the time course for neocortical spine modification during learning. With eyeblink conditioning, subjects are presented with a neutral, conditioned stimulus (CS) paired with a salient, unconditioned stimulus (US) to elicit an unconditioned response (UR). With multiple CS-US pairings, subjects learn to associate the CS with the US and exhibit a conditioned response (CR) when presented with the CS. Trace conditioning is when there is a stimulus free interval between the CS and the US. Utilizing trace-eyeblink conditioning with whisker stimulation as the CS (whisker-trace-eyeblink: WTEB), previous findings have shown that primary somatosensory (barrel) cortex is required for both acquisition and retention of the trace-association. Additionally, prior findings demonstrated that WTEB acquisition results in an expansion of the cytochrome oxidase whisker representation and synaptic modification in layer IV of barrel cortex. To further explore these findings and determine the time course for neocortical learning-induced spine modification, the present study utilized WTEB conditioning to examine Golgi-Cox stained neurons in layer IV of barrel cortex. Findings from this study demonstrated a training-dependent spine proliferation in layer IV of barrel cortex during trace associative learning. Furthermore, findings from this study showing that filopodia-like spines exhibited a similar pattern to the overall spine density further suggests that reorganization of synaptic contacts set the foundation for learning-induced neocortical modifications through the different neocortical layers. PMID:24760074

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

ERIC Educational Resources Information Center

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…

Purkinje Cell Activity in the Cerebellar Anterior Lobe after Rabbit Eyeblink Conditioning

ERIC Educational Resources Information Center

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.…

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

ERIC Educational Resources Information Center

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…

Medial Auditory Thalamus Is Necessary for Acquisition and Retention of Eyeblink Conditioning to Cochlear Nucleus Stimulation

ERIC Educational Resources Information Center

Halverson, Hunter E.; Poremba, Amy; Freeman, John H.

2015-01-01

Associative learning tasks commonly involve an auditory stimulus, which must be projected through the auditory system to the sites of memory induction for learning to occur. The cochlear nucleus (CN) projection to the pontine nuclei has been posited as the necessary auditory pathway for cerebellar learning, including eyeblink conditioning.…

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

PubMed Central

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 pathology. PMID:26903886

Neurotoxic lesions of the dorsal and ventral hippocampus impair acquisition and expression of trace-conditioned fear-potentiated startle in rats.

PubMed

Trivedi, Mehul A; Coover, Gary D

2006-04-03

Pavlovian delay conditioning, in which a conditioned stimulus (CS) and unconditioned stimulus (US) co-terminate, is thought to reflect non-declarative memory. In contrast, trace conditioning, in which the CS and US are temporally separate, is thought to reflect declarative memory. Hippocampal lesions impair acquisition and expression of trace conditioning measured by the conditioned freezing and eyeblink responses, while having little effect on the acquisition of delay conditioning. Recent evidence suggests that lesions of the ventral hippocampus (VH) impair conditioned fear under conditions in which dorsal hippocampal (DH) lesions have little effect. In the present study, we examined the time-course of fear expression after delay and trace conditioning using the fear-potentiated startle (FPS) reflex, and the effects of pre- and post-training lesions to the VH and DH on trace-conditioned FPS. We found that both delay- and trace-conditioned rats displayed significant FPS near the end of the CS relative to the unpaired control group. In contrast, trace-conditioned rats displayed significant FPS throughout the duration of the trace interval, whereas FPS decayed rapidly to baseline after CS offset in delay-conditioned rats. In experiment 2, both DH and VH lesions were found to significantly reduce the overall magnitude of FPS compared to the control group, however, no differences were found between the DH and VH groups. These findings support a role for both the DH and VH in trace fear conditioning, and suggest that the greater effect of VH lesions on conditioned fear might be specific to certain measures of fear.

Classical eyeblink conditioning in Parkinson's disease.

PubMed

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.

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

PubMed

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. Copyright © 2014 Elsevier B.V. All rights reserved.

Acute Stress Facilitates Trace Eyeblink Conditioning in C57BL/6 Male Mice and Increases the Excitability of Their CA1 Pyramidal Neurons

ERIC Educational Resources Information Center

Weiss, Craig; Sametsky, Evgeny; Sasse, Astrid; Spiess, Joachim; Disterhoft, John F.

2005-01-01

The effects of stress (restraint plus tail shock) on hippocampus-dependent trace eyeblink conditioning and hippocampal excitability were examined in C57BL/6 male mice. The results indicate that the stressor significantly increased the concentration of circulating corticosterone, the amount and rate of learning relative to nonstressed conditioned…

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

PubMed

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 learned helplessness. Applications of these findings of enhanced proactive interference in BI individuals to pre-exposure therapies to reduce anxiety disorders such as posttraumatic stress disorder (PTSD) will be discussed.

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

PubMed Central

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 learned helplessness. Applications of these findings of enhanced proactive interference in BI individuals to pre-exposure therapies to reduce anxiety disorders such as posttraumatic stress disorder (PTSD) will be discussed. PMID:27014001

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

PubMed

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.

I Think, Therefore Eyeblink

PubMed Central

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

2016-01-01

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. PMID:26905277

Why trace and delay conditioning are sometimes (but not always) hippocampal dependent: A computational model

PubMed Central

Moustafa, Ahmed A.; Wufong, Ella; Servatius, Richard J.; Pang, Kevin C. H.; Gluck, Mark A.; Myers, Catherine E.

2013-01-01

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. PMID:23178699

PKMζ Inhibition Reverses Learning-Induced Increases in Hippocampal Synaptic Strength and Memory during Trace Eyeblink Conditioning

PubMed Central

Madroñal, Noelia; Gruart, Agnès; Sacktor, Todd C.; Delgado-García, José M.

2010-01-01

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 (PKMζ), 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 PKMζ is necessary for the maintenance of synaptic potentiation induced after learning, the effects of ZIP (zeta inhibitory peptide), a PKMζ inhibitor, on eyeblink-conditioned mice were studied. PKMζ 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, PKMζ inhibition both reversed tetanic LTP and prevented the expected LTP-mediated deleterious effects on eyeblink conditioning. Thus, PKMζ 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. PMID:20454458

A Variable Oscillator Underlies the Measurement of Time Intervals in the Rostral Medial Prefrontal Cortex during Classical Eyeblink Conditioning in Rabbits.

PubMed

Caro-Martín, C Rocío; Leal-Campanario, Rocío; Sánchez-Campusano, Raudel; Delgado-García, José M; Gruart, Agnès

2015-11-04

We were interested in determining whether rostral medial prefrontal cortex (rmPFC) neurons participate in the measurement of conditioned stimulus-unconditioned stimulus (CS-US) time intervals during classical eyeblink conditioning. Rabbits were conditioned with a delay paradigm consisting of a tone as CS. The CS started 50, 250, 500, 1000, or 2000 ms before and coterminated with an air puff (100 ms) directed at the cornea as the US. Eyelid movements were recorded with the magnetic search coil technique and the EMG activity of the orbicularis oculi muscle. Firing activities of rmPFC neurons were recorded across conditioning sessions. Reflex and conditioned eyelid responses presented a dominant oscillatory frequency of ≈12 Hz. The firing rate of each recorded neuron presented a single peak of activity with a frequency dependent on the CS-US interval (i.e., ≈12 Hz for 250 ms, ≈6 Hz for 500 ms, and≈3 Hz for 1000 ms). Interestingly, rmPFC neurons presented their dominant firing peaks at three precise times evenly distributed with respect to CS start and also depending on the duration of the CS-US interval (only for intervals of 250, 500, and 1000 ms). No significant neural responses were recorded at very short (50 ms) or long (2000 ms) CS-US intervals. rmPFC neurons seem not to encode the oscillatory properties characterizing conditioned eyelid responses in rabbits, but are probably involved in the determination of CS-US intervals of an intermediate range (250-1000 ms). We propose that a variable oscillator underlies the generation of working memories in rabbits. The way in which brains generate working memories (those used for the transient processing and storage of newly acquired information) is still an intriguing question. Here, we report that the firing activities of neurons located in the rostromedial prefrontal cortex recorded in alert behaving rabbits are controlled by a dynamic oscillator. This oscillator generated firing frequencies in a variable band of 3-12 Hz depending on the conditioned stimulus-unconditioned stimulus intervals (1 s, 500 ms, 250 ms) selected for classical eyeblink conditioning of behaving rabbits. Shorter (50 ms) and longer (2 s) intervals failed to activate the oscillator and prevented the acquisition of conditioned eyelid responses. This is an unexpected mechanism to generate sustained firing activities in neural circuits generating working memories. Copyright © 2015 the authors 0270-6474/15/3514809-13$15.00/0.

Trace Eyeblink Conditioning in Mice Is Dependent upon the Dorsal Medial Prefrontal Cortex, Cerebellum, and Amygdala: Behavioral Characterization and Functional Circuitry1,2,3

PubMed Central

Taylor, William; Kalmbach, Brian; Desai, Niraj S.

2015-01-01

Abstract Trace eyeblink conditioning is useful for studying the interaction of multiple brain areas in learning and memory. The goal of the current work was to determine whether trace eyeblink conditioning could be established in a mouse model in the absence of elicited startle responses and the brain circuitry that supports this learning. We show here that mice can acquire trace conditioned responses (tCRs) devoid of startle while head-restrained and permitted to freely run on a wheel. Most mice (75%) could learn with a trace interval of 250 ms. Because tCRs were not contaminated with startle-associated components, we were able to document the development and timing of tCRs in mice, as well as their long-term retention (at 7 and 14 d) and flexible expression (extinction and reacquisition). To identify the circuitry involved, we made restricted lesions of the medial prefrontal cortex (mPFC) and found that learning was prevented. Furthermore, inactivation of the cerebellum with muscimol completely abolished tCRs, demonstrating that learned responses were driven by the cerebellum. Finally, inactivation of the mPFC and amygdala in trained animals nearly abolished tCRs. Anatomical data from these critical regions showed that mPFC and amygdala both project to the rostral basilar pons and overlap with eyelid-associated pontocerebellar neurons. The data provide the first report of trace eyeblink conditioning in mice in which tCRs were driven by the cerebellum and required a localized region of mPFC for acquisition. The data further reveal a specific role for the amygdala as providing a conditioned stimulus-associated input to the cerebellum. PMID:26464998

Inactivation of the superior cerebellar peduncle blocks expression but not acquisition of the rabbit's classically conditioned eye-blink response.

PubMed

Krupa, D J; Thompson, R F

1995-05-23

The localization of sites of memory formation within the mammalian brain has proven to be a formidable task even for simple forms of learning and memory. Recent studies have demonstrated that reversibly inactivating a localized region of cerebellum, including the dorsal anterior interpositus nucleus, completely prevents acquisition of the conditioned eye-blink response with no effect upon subsequent learning without inactivation. This result indicates that the memory trace for this type of learning is located either (i) within this inactivated region of cerebellum or (ii) within some structure(s) efferent from the cerebellum to which output from the interpositus nucleus ultimately projects. To distinguish between these possibilities, two groups of rabbits were conditioned (by using two conditioning stimuli) while the output fibers of the interpositus (the superior cerebellar peduncle) were reversibly blocked with microinjections of the sodium channel blocker tetrodotoxin. Rabbits performed no conditioned responses during this inactivation training. However, training after inactivation revealed that the rabbits (trained with either conditioned stimulus) had fully learned the response during the previous inactivation training. Cerebellar output, therefore, does not appear to be essential for acquisition of the learned response. This result, coupled with the fact that inactivation of the appropriate region of cerebellum completely prevents learning, provides compelling evidence supporting the hypothesis that the essential memory trace for the classically conditioned eye-blink response is localized within the cerebellum.

Effects of inferior olive lesion on fear-conditioned bradycardia

PubMed Central

Kotajima, Hiroko; Sakai, Kazuhisa; Hashikawa, Tsutomu

2014-01-01

The inferior olive (IO) sends excitatory inputs to the cerebellar cortex and cerebellar nuclei through the climbing fibers. In eyeblink conditioning, a model of motor learning, the inactivation of or a lesion in the IO impairs the acquisition or expression of conditioned eyeblink responses. Additionally, climbing fibers originating from the IO are believed to transmit the unconditioned stimulus to the cerebellum in eyeblink conditioning. Studies using fear-conditioned bradycardia showed that the cerebellum is associated with adaptive control of heart rate. However, the role of inputs from the IO to the cerebellum in fear-conditioned bradycardia has not yet been investigated. To examine this possible role, we tested fear-conditioned bradycardia in mice by selective disruption of the IO using 3-acetylpyridine. In a rotarod test, mice with an IO lesion were unable to remain on the rod. The number of neurons of IO nuclei in these mice was decreased to ∼40% compared with control mice. Mice with an IO lesion did not show changes in the mean heart rate or in heart rate responses to a conditioned stimulus, or in their responses to a painful stimulus in a tail-flick test. However, they did show impairment of the acquisition/expression of conditioned bradycardia and attenuation of heart rate responses to a pain stimulus used as an unconditioned stimulus. These results indicate that the IO inputs to the cerebellum play a key role in the acquisition/expression of conditioned bradycardia. PMID:24784584

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

PubMed Central

Holloway, Jacqueline L.; Trivedi, Payal; Myers, Catherine E.; Servatius, Richard J.

2012-01-01

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 behavioral 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 framework. PMID:23162449

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

PubMed

Holloway, Jacqueline L; Trivedi, Payal; Myers, Catherine E; Servatius, Richard J

2012-01-01

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 behavioral 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 framework.

Interactions among Collective Spectators Facilitate Eyeblink Synchronization

PubMed Central

Nomura, Ryota; Liang, Yingzong; Okada, Takeshi

2015-01-01

Whereas the entrainment of movements and aspirations among audience members has been known as a basis of collective excitement in the theater, the role of the entrainment of cognitive processes among audience members is still unclear. In the current study, temporal patterns of the audience’s attention were observed using eyeblink responses. To determine the effect of interactions among audience members on cognitive entrainment, as well as its direction (attractive or repulsive), the eyeblink synchronization of the following two groups were compared: (1) the experimental condition, where the audience members (seven frequent viewers and seven first-time viewers) viewed live performances in situ, and (2) the control condition, where the audience members (15 frequent viewers and 15 first-time viewers) viewed videotaped performances in individual experimental settings (results reported in previous study.) The results of this study demonstrated that the mean values of a measure of asynchrony (i.e., D interval) were much lower for the experimental condition than for the control condition. Frequent viewers had a moderate attractive effect that increased as the story progressed, while a strong attractive effect was observed throughout the story for first-time viewers. The attractive effect of interactions among a group of spectators was discussed from the viewpoint of cognitive and somatic entrainment in live performances. PMID:26479405

Cross-modal Savings in the Contralateral Eyelid Conditioned Response

PubMed Central

Campolattaro, Matthew M.; Buss, Eric W.; Freeman, John H.

2015-01-01

The present experiment monitored bilateral eyelid responses during eyeblink conditioning in rats trained with a unilateral unconditioned stimulus (US). Three groups of rats were used to determine if cross-modal savings occurs when the location of the US is switched from one eye to the other. Rats in each group first received paired or unpaired eyeblink conditioning with a conditioned stimulus (tone or light; CS) and a unilateral periorbital electrical stimulation US. All rats were subsequently given paired training, but with the US location (Group 1), CS modality (Group 2), or US location and CS modality (Group 3) changed. Changing the location of the US alone resulted in an immediate transfer of responding in both eyelids (Group 1) in rats that received paired training prior to the transfer session. Rats in groups 2 and 3 that initially received paired training showed facilitated learning to the new CS modality during the transfer sessions, indicating that cross-modal savings occurs whether or not the location of the US is changed. All rats that were initially given unpaired training acquired conditioned eyeblink responses similar to de novo acquisition rate during the transfer sessions. Savings of CR incidence was more robust than savings of CR amplitude when the US switched sides, a finding that has implications for elucidating the neural mechanisms of cross-modal savings. PMID:26501170

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.

PubMed

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 (p<0.05, Liebermeister test). Cerebellar subjects could be subdivided into two groups: a smaller group (n=5) which showed acquisition, 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 acquire CRs is not only reduced but abolished. Subjects with lesions outside these critical areas, on the other hand show preserved acquisition, extinction and saving effects. As a consequence, studies in human subjects with cerebellar lesions do not allow drawing conclusions on CR extinction and savings. In light of the present findings, previous reports of reduced extinction in humans with circumscribed cerebellar disease need to be critically reevaluated. Copyright © 2016 Elsevier Ltd. All rights reserved.

Eyeblink Synchrony in Multimodal Human-Android Interaction.

PubMed

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.

Eyeblink Synchrony in Multimodal Human-Android Interaction

PubMed Central

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

2016-01-01

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. PMID:28009014

An assessment of the pattern of spontaneous eyeblink activity under the influence of topical ocular anaesthesia.

PubMed

Naase, Taher; Doughty, Michael J; Button, Norman F

2005-04-01

To determine whether there is a change in the pattern of human eyeblink events under topical ocular anaesthesia. Forty male subjects, aged between 19 and 52 years and with no significant ocular surface disease, were recruited. Their spontaneous eyeblink activity, in primary eye gaze position and in silence, was recorded for 5-min periods, before and after instillation of benoxinate 0.4% eyedrops. The surface anaesthesia was confirmed by aesthesiometry. The spontaneous eyeblink rate (SEBR) decreased from 9.1+/-4.0 blinks/min to an average of 5.7+/-3.3 blinks/min, with 37 subjects showing a decreased eyeblink rate under anaesthesia. Three blink patterns were observed before anaesthesia (symmetrical, J-type and I-type) and these were essentially unchanged under anaesthesia. These studies confirm that the SEBR is usually reduced under surface anaesthesia (so is sensitive to exogenous control) but the pattern of the eyeblink activity is unchanged (so is less sensitive to exogenous control). The removal of exogenous stimuli by anaesthesia does not shift the eyeblink pattern to a single type, so indicates endogenous control.

Role of Muscarinic Acetylcholine Receptors in Serial Feature-Positive Discrimination Task during Eyeblink Conditioning in Mice

PubMed Central

Rahman, Md. Ashrafur; Tanaka, Norifumi; Usui, Koji; Kawahara, Shigenori

2016-01-01

We investigated the role of muscarinic acetylcholine receptors (mAChRs) in eyeblink serial feature-positive discrimination learning in mice using the mAChR antagonist. A 2-s light cue was delivered 5 or 6 s before the presentation of a 350-ms tone paired with a 100-ms periorbital electrical shock (cued trial) but not before the tone-alone presentation (non-cued trial). Mice received 30 cued and 30 non-cued trials each day in a random order. We found that saline-injected control mice were successfully discriminating between cued and non-cued trials within a few days of conditioning. The mice responded more frequently to the tone in cued trials than in non-cued trials. Analysis of conditioned response (CR) dynamics revealed that the CR onset latency was shorter in cued trials than in non-cued trials, despite the CR peak amplitude not differing significantly between the two conditions. In contrast, scopolamine-injected mice developed an equal number of CRs with similar temporal patterns irrespective of the presence of the cue during the 7 days of conditioning, indicating in a failure to acquire conditional discrimination. In addition, the scopolamine administration to the control mice after they had successfully acquired discrimination did not impair the conditional discrimination and expression of pre-acquired CR. These results suggest that mAChRs may play a pivotal role in memory formation in the conditional brain state associated with the feature cue; however they are unlikely to be involved in the development of discrimination after conditional memory had formed in the serial feature-positive discrimination task during eyeblink conditioning. PMID:26808980

Intrahippocampal LSD accelerates learning and desensitizes the 5-HT(2A) receptor in the rabbit, Romano et al.

PubMed

Romano, Anthony G; Quinn, Jennifer L; Li, Luchuan; Dave, Kuldip D; Schindler, Emmanuelle A; Aloyo, Vincent J; Harvey, John A

2010-10-01

Parenteral injections of d-lysergic acid diethylamide (LSD), a serotonin 5-HT(2A) receptor agonist, enhance eyeblink conditioning. Another hallucinogen, (±)-1(2, 5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI), was shown to elicit a 5-HT(2A)-mediated behavior (head bobs) after injection into the hippocampus, a structure known to mediate trace eyeblink conditioning. This study aims to determine if parenteral injections of the hallucinogens LSD, d,l-2,5-dimethoxy-4-methylamphetamine, and 5-methoxy-dimethyltryptamine elicit the 5-HT(2A)-mediated behavior of head bobs and whether intrahippocampal injections of LSD would produce head bobs and enhance trace eyeblink conditioning. LSD was infused into the dorsal hippocampus just prior to each of eight conditioning sessions. One day after the last infusion of LSD, DOI was infused into the hippocampus to determine whether there had been a desensitization of the 5-HT(2A) receptor as measured by a decrease in DOI-elicited head bobs. Acute parenteral or intrahippocampal LSD elicited a 5-HT(2A) but not a 5-HT(2C)-mediated behavior, and chronic administration enhanced conditioned responding relative to vehicle controls. Rabbits that had been chronically infused with 3 or 10 nmol per side of LSD during Pavlovian conditioning and then infused with DOI demonstrated a smaller increase in head bobs relative to controls. LSD produced its enhancement of Pavlovian conditioning through an effect on 5-HT(2A) receptors located in the dorsal hippocampus. The slight, short-lived enhancement of learning produced by LSD appears to be due to the development of desensitization of the 5-HT(2A) receptor within the hippocampus as a result of repeated administration of its agonist (LSD).

The emotional startle effect is disrupted by a concurrent working memory task.

PubMed

King, Rosemary; Schaefer, Alexandre

2011-02-01

Working memory (WM) processes are often thought to play an important role in the cognitive regulation of negative emotions. However, little is known about how they influence emotional processing. We report two experiments that tested whether a concurrent working memory task could modulate the emotional startle eyeblink effect, a well-known index of emotional processing. In both experiments, emotionally negative and neutral pictures were viewed in two conditions: a "cognitive load" (CL) condition, in which participants had to actively maintain information in working memory (WM) while viewing the pictures, and a control "no load" (NL) condition. Picture-viewing instructions were identical across CL and NL. In both experiments, results showed a significant reduction of the emotional modulation of the startle eyeblink reflex in the CL condition compared to the NL condition. These findings suggest that a concurrent WM task disrupts emotional processing even when participants are directing visual focus on emotionally relevant information. Copyright © 2010 Society for Psychophysiological Research.

Uncertainty of trial timing enhances acquisition of conditioned eyeblinks in anxiety vulnerable individuals.

PubMed

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

2016-05-01

Recent work has found that behaviorally inhibited (BI) individuals exhibit enhanced eyeblink conditioning in omission and yoked training as well as with schedules of partial reinforcement. We hypothesized that spacing CS-US paired trials over a longer period of time by extending and varying the inter-trial interval (ITI) would facilitate learning. All participants completed the Adult Measure of Behavioural Inhibition (AMBI) and were grouped as behaviorally inhibited (BI) and non-behaviorally inhibited (NI) based on a median split score of 15.5. All participants received 3 US alone trials and 30CS-US paired trials for acquisition training and 20CS alone trials for extinction training in one session. Conditioning stimuli were a 500 ms tone conditioned stimulus (CS) and a 50-ms air puff unconditional stimulus (US). Participants were randomly assigned to receive a short ITI (mean=30+/- 5s), a long ITI (mean=57+/- 5s) or a variable long ITI (mean=57 s, range 25-123 s). No significant ITI effects were observed for acquisition or extinction. Overall, anxiety vulnerable individuals exhibited enhanced conditioned eyeblink responses as compared to non-vulnerable individuals. This enhanced acquisition of CRs was significant in spaced training with a variable long ITI, but not the short or long ITI. There were no significant effects of ITI or BI on extinction. These findings are interpreted based on the idea that uncertainty plays a role in anxiety and can enhance associative learning in anxiety vulnerable individuals. Copyright © 2016 Elsevier B.V. All rights reserved.

Cerebellar transcranial direct current stimulation interacts with BDNF Val66Met in motor learning.

PubMed

van der Vliet, Rick; Jonker, Zeb D; Louwen, Suzanne C; Heuvelman, Marco; de Vreede, Linda; Ribbers, Gerard M; De Zeeuw, Chris I; Donchin, Opher; Selles, Ruud W; van der Geest, Jos N; Frens, Maarten A

2018-04-11

Cerebellar transcranial direct current stimulation has been reported to enhance motor associative learning and motor adaptation, holding promise for clinical application in patients with movement disorders. However, behavioral benefits from cerebellar tDCS have been inconsistent. Identifying determinants of treatment success is necessary. BDNF Val66Met is a candidate determinant, because the polymorphism is associated with motor skill learning and BDNF is thought to mediate tDCS effects. We undertook two cerebellar tDCS studies in subjects genotyped for BDNF Val66Met. Subjects performed an eyeblink conditioning task and received sham, anodal or cathodal tDCS (N = 117, between-subjects design) or a vestibulo-ocular reflex adaptation task and received sham and anodal tDCS (N = 51 subjects, within-subjects design). Performance was quantified as a learning parameter from 0 to 100%. We investigated (1) the distribution of the learning parameter with mixture modeling presented as the mean (M), standard deviation (S) and proportion (P) of the groups, and (2) the role of BDNF Val66Met and cerebellar tDCS using linear regression presented as the regression coefficients (B) and odds ratios (OR) with equally-tailed intervals (ETIs). For the eyeblink conditioning task, we found distinct groups of learners (M Learner  = 67.2%; S Learner  = 14.7%; P Learner  = 61.6%) and non-learners (M Non-learner  = 14.2%; S Non-learner  = 8.0%; P Non-learner  = 38.4%). Carriers of the BDNF Val66Met polymorphism were more likely to be learners (OR = 2.7 [1.2 6.2]). Within the group of learners, anodal tDCS supported eyeblink conditioning in BDNF Val66Met non-carriers (B = 11.9% 95%ETI = [0.8 23.0]%), but not in carriers (B = 1.0% 95%ETI = [-10.2 12.1]%). For the vestibulo-ocular reflex adaptation task, we found no effect of BDNF Val66Met (B = -2.0% 95%ETI = [-8.7 4.7]%) or anodal tDCS in either carriers (B = 3.4% 95%ETI = [-3.2 9.5]%) or non-carriers (B = 0.6% 95%ETI = [-3.4 4.8]%). Finally, we performed additional saccade and visuomotor adaptation experiments (N = 72) to investigate the general role of BDNF Val66Met in cerebellum-dependent learning and found no difference between carriers and non-carriers for both saccade (B = 1.0% 95%ETI = [-8.6 10.6]%) and visuomotor adaptation (B = 2.7% 95%ETI = [-2.5 7.9]%). The specific role for BDNF Val66Met in eyeblink conditioning, but not vestibulo-ocular reflex adaptation, saccade adaptation or visuomotor adaptation could be related to dominance of the role of simple spike suppression of cerebellar Purkinje cells with a high baseline firing frequency in eyeblink conditioning. Susceptibility of non-carriers to anodal tDCS in eyeblink conditioning might be explained by a relatively larger effect of tDCS-induced subthreshold depolarization in this group, which might increase the spontaneous firing frequency up to the level of that of the carriers. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Spontaneous Eye-Blinking and Stereotyped Behavior in Older Persons with Mental Retardation

ERIC Educational Resources Information Center

Roebel, Amanda M.; MacLean, William E., Jr.

2007-01-01

Previous research indicates that abnormal stereotyped movements are associated with central dopamine dysfunction and that eye-blink rate is a noninvasive, in vivo measure of dopamine function. We measured the spontaneous eye-blinking and stereotyped behavior of older adults with severe/profound mental retardation living in a state mental…

Excitatory Cerebellar Nucleocortical Circuit Provides Internal Amplification during Associative Conditioning.

PubMed

Gao, Zhenyu; Proietti-Onori, Martina; Lin, Zhanmin; Ten Brinke, Michiel M; Boele, Henk-Jan; Potters, Jan-Willem; Ruigrok, Tom J H; Hoebeek, Freek E; De Zeeuw, Chris I

2016-02-03

Closed-loop circuitries between cortical and subcortical regions can facilitate precision of output patterns, but the role of such networks in the cerebellum remains to be elucidated. Here, we characterize the role of internal feedback from the cerebellar nuclei to the cerebellar cortex in classical eyeblink conditioning. We find that excitatory output neurons in the interposed nucleus provide efference-copy signals via mossy fibers to the cerebellar cortical zones that belong to the same module, triggering monosynaptic responses in granule and Golgi cells and indirectly inhibiting Purkinje cells. Upon conditioning, the local density of nucleocortical mossy fiber terminals significantly increases. Optogenetic activation and inhibition of nucleocortical fibers in conditioned animals increases and decreases the amplitude of learned eyeblink responses, respectively. Our data show that the excitatory nucleocortical closed-loop circuitry of the cerebellum relays a corollary discharge of premotor signals and suggests an amplifying role of this circuitry in controlling associative motor learning. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Modification of persistent responses in medial prefrontal cortex during learning in trace eyeblink conditioning

PubMed Central

2014-01-01

Persistent spiking in response to a discrete stimulus is considered to reflect the active maintenance of a memory for that stimulus until a behavioral response is made. This response pattern has been reported in learning paradigms that impose a temporal gap between stimulus presentation and behavioral response, including trace eyeblink conditioning. However, it is unknown whether persistent responses are acquired as a function of learning or simply represent an already existing category of response type. This fundamental question was addressed by recording single-unit activity in the medial prefrontal cortex (mPFC) of rabbits during the initial learning phase of trace eyeblink conditioning. Persistent responses to the tone conditioned stimulus were observed in the mPFC during the very first training sessions. Further analysis revealed that most cells with persistent responses showed this pattern during the very first training trial, before animals had experienced paired training. However, persistent cells showed reliable decreases in response magnitude over the first training session, which were not observed on the second day of training or for sessions in which learning criterion was met. This modification of response magnitude was specific to persistent responses and was not observed for cells showing phasic tone-evoked responses. The data suggest that persistent responses to discrete stimuli do not require learning but that the ongoing robustness of such responses over the course of training is modified as a result of experience. Putative mechanisms for this modification are discussed, including changes in cellular or network properties, neuromodulatory tone, and/or the synaptic efficacy of tone-associated inputs. PMID:25080570

Implicit and explicit learning in schizophrenics treated with olanzapine and with classic neuroleptics.

PubMed

Stevens, Andreas; Schwarz, Jürgen; Schwarz, Benedikt; Ruf, Ilona; Kolter, Thomas; Czekalla, Joerg

2002-03-01

Novel and classic neuroleptics differ in their effects on limbic striatal/nucleus accumbens (NA) and prefrontal cortex (PFC) dopamine turnover, suggesting differential effects on implicit and explicit learning as well as on anhedonia. The present study investigates whether such differences can be demonstrated in a naturalistic sample of schizophrenic patients. Twenty-five inpatients diagnosed with DSM-IV schizophrenic psychosis and treated for at least 14 days with the novel neuroleptic olanzapine were compared with 25 schizophrenics taking classic neuroleptics and with 25 healthy controls, matched by age and education level. PFC/NA-dependent implicit learning was assessed by a serial reaction time task (SRTT) and compared with cerebellum-mediated classical eye-blink conditioning and explicit visuospatial memory. Anhedonia was measured with the Snaith-Hamilton-Pleasure Scale (SHAPS). Implicit (SRTT) and psychomotor speed, but not explicit (visuospatial) learning were superior in the olanzapine-treated group as compared to the patients on classic neuroleptics. Compared to healthy controls, olanzapine-treated schizophrenics showed similar implicit learning, but reduced explicit (visuospatial) memory performance. Acquisition of eyeblink conditioning was not different between the three groups. There was no difference with regard to anhedonia and SANS scores between the patients. Olanzapine seems to interfere less with unattended learning and motor speed than classical neuroleptics. In daily life, this may translate into better adaptation to a rapidly changing environment. The effects seem specific, as in explicit learning and eyeblink conditioning no difference to classic NL was found.

Extinction, reacquisition, and rapid forgetting of eyeblink conditioning in developing rats

PubMed Central

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 Experiment 1, post-natal day (P) 17 and 24 rats were trained to a criterion of 80% conditioned responses (CRs) using stimulation of the middle cerebellar peduncle (MCP) as a conditioned stimulus (CS). Stimulation CS-alone extinction training commenced 24 h later, followed by reacquisition training after the fourth extinction session. Contrary to expected results, rats trained starting on P17 showed significantly fewer CRs to stimulation CS-alone presentations relative to P24s, including fewer CRs as early as the first block of extinction session 1. Furthermore, the P17 group was slower to reacquire following extinction. Experiment 2 was run to determine the extent to which the low CR percentage observed in P17s early in extinction reflected rapid forgetting versus rapid extinction. Twenty-four hours after reaching criterion, subjects were trained in a session split into 50 stimulation CS-unconditioned stimulus paired trials followed immediately by 50 stimulation CS-alone trials. With this “immediate” extinction protocol, CR percentages during the first block of stimulation CS-alone presentations were equivalent to terminal acquisition levels at both ages but extinction was more rapid in the P17 group. These findings indicate that forgetting is observed in P17 relative to P24 rats 24 h following acquisition. The forgetting in P17 rats has important implications for the neurobiological mechanisms of memory in the developing cerebellum. PMID:25403458

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

PubMed Central

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

2017-01-01

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. PMID:28220882

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

PubMed

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.

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

ERIC Educational Resources Information Center

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…

Biobehavioral Markers of Adverse Effect in Fetal Alcohol Spectrum Disorders

PubMed Central

Jacobson, Sandra W.; Jacobson, Joseph L.; Stanton, Mark E.; Meintjes, Ernesta M.; Molteno, Christopher D.

2011-01-01

Identification of children with fetal alcohol spectrum disorders (FASD) is difficult because information regarding prenatal exposure is often lacking, a large proportion of affected children do not exhibit facial anomalies, and no distinctive behavioral phenotype has been identified. Castellanos and Tannock have advocated going beyond descriptive symptom-based approaches to diagnosis to identify biomarkers derived from cognitive neuroscience. Classical eyeblink conditioning and magnitude comparison are particularly promising biobehavioral markers of FASD—eyeblink conditioning because a deficit in this elemental form of learning characterizes a very large proportion of alcohol-exposed children; magnitude comparison because it is a domain of higher order cognitive function that is among the most sensitive to fetal alcohol exposure. Because the neural circuitry mediating both these biobehavioral markers is well understood, they have considerable potential for advancing understanding of the pathophysiology of FASD, which can contribute to development of treatments targeted to the specific deficits that characterize this disorder. PMID:21541763

Phase Matters: Responding to and Learning about Peripheral Stimuli Depends on Hippocampal ? Phase at Stimulus Onset

ERIC Educational Resources Information Center

Nokia, Miriam S.; Waselius, Tomi; Mikkonen, Jarno E.; Wikgren, Jan; Penttonen, Markku

2015-01-01

Hippocampal ? (3-12 Hz) oscillations are implicated in learning and memory, but their functional role remains unclear. We studied the effect of the phase of local ? oscillation on hippocampal responses to a neutral conditioned stimulus (CS) and subsequent learning of classical trace eyeblink conditioning in adult rabbits. High-amplitude, regular…

The distressed (Type D) personality factor of social inhibition, but not negative affectivity, enhances eyeblink conditioning.

PubMed

Allen, M T; Handy, J D; Blankenship, M R; Servatius, R J

2018-06-01

Recent work has focused on a learning diathesis model in which specific personality factors such as behavioral inhibition (BI) may influence associative learning and in turn increase risk for the development of anxiety disorders. We have found in a series of studies that individuals self-reporting high levels of BI exhibit enhanced acquisition of conditioned eyeblinks. In the study reported here, hypotheses were extended to include distressed (Type D) personality which has been found to be related to BI. Type D personality is measured with the DS-14 scale which includes two subscales measuring negative affectivity (NA) and social inhibition (SI). We hypothesized that SI, which is similar to BI, would result in enhanced acquisition while the effect of NA is unclear. Eighty nine participants completed personality inventories including the Adult Measure of Behavioral Inhibition (AMBI) and DS-14. All participants received 60 acquisition trials with a 500 ms, 1000 Hz, tone CS and a co-terminating 50 ms, 5 psi corneal airpuff US. Participants received either 100% CS-US paired trials or a schedule of partial reinforcement where 50% US alone trials were intermixed into CS-US training. Acquisition of CRs did not differ between the two training protocols. Whereas BI was significantly related to Type D, SI, and NA, only BI and SI individuals exhibited enhanced acquisition of conditioned eyeblinks as compared to non-inhibited individuals. Personality factors now including social inhibition can be used to identify individuals who express enhanced associative learning which lends further support to a learning diathesis model of anxiety disorders. Copyright © 2018 Elsevier B.V. All rights reserved.

Eye-blink behaviors in 71 species of primates.

PubMed

Tada, Hideoki; Omori, Yasuko; Hirokawa, Kumi; Ohira, Hideki; Tomonaga, Masaki

2013-01-01

The present study was performed to investigate the associations between eye-blink behaviors and various other factors in primates. We video-recorded 141 individuals across 71 primate species and analyzed the blink rate, blink duration, and "isolated" blink ratio (i.e., blinks without eye or head movement) in relation to activity rhythms, habitat types, group size, and body size factors. The results showed close relationships between three types of eye-blink measures and body size factors. All of these measures increased as a function of body weight. In addition, diurnal primates showed more blinks than nocturnal species even after controlling for body size factors. The most important findings were the relationships between eye-blink behaviors and social factors, e.g., group size. Among diurnal primates, only the blink rate was significantly correlated even after controlling for body size factors. The blink rate increased as the group size increased. Enlargement of the neocortex is strongly correlated with group size in primate species and considered strong evidence for the social brain hypothesis. Our results suggest that spontaneous eye-blinks have acquired a role in social communication, similar to grooming, to adapt to complex social living during primate evolution.

Eye-Blink Behaviors in 71 Species of Primates

PubMed Central

Tada, Hideoki; Omori, Yasuko; Hirokawa, Kumi; Ohira, Hideki; Tomonaga, Masaki

2013-01-01

The present study was performed to investigate the associations between eye-blink behaviors and various other factors in primates. We video-recorded 141 individuals across 71 primate species and analyzed the blink rate, blink duration, and “isolated” blink ratio (i.e., blinks without eye or head movement) in relation to activity rhythms, habitat types, group size, and body size factors. The results showed close relationships between three types of eye-blink measures and body size factors. All of these measures increased as a function of body weight. In addition, diurnal primates showed more blinks than nocturnal species even after controlling for body size factors. The most important findings were the relationships between eye-blink behaviors and social factors, e.g., group size. Among diurnal primates, only the blink rate was significantly correlated even after controlling for body size factors. The blink rate increased as the group size increased. Enlargement of the neocortex is strongly correlated with group size in primate species and considered strong evidence for the social brain hypothesis. Our results suggest that spontaneous eye-blinks have acquired a role in social communication, similar to grooming, to adapt to complex social living during primate evolution. PMID:23741522

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

PubMed Central

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. PMID:25904874

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

PubMed

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.

Galantamine Facilitates Acquisition of a Trace-Conditioned Eyeblink Response in Healthy, Young Rabbits

ERIC Educational Resources Information Center

Simon, Barbara B.; Knuckley, Bryan; Powell, Donald A.

2004-01-01

Previous work has demonstrated that drugs increasing brain concentrations of acetylcholine can enhance cognition in aging and brain-damaged organisms. The present study assessed whether galantamine (GAL), an allosteric modulator of nicotinic cholinergic receptors and weak acetylcholinesterase inhibitor, could improve acquisition and retention of…

Emotionally excited eyeblink-rate variability predicts an experience of transportation into the narrative world

PubMed Central

Nomura, Ryota; Hino, Kojun; Shimazu, Makoto; Liang, Yingzong; Okada, Takeshi

2015-01-01

Collective spectator communications such as oral presentations, movies, and storytelling performances are ubiquitous in human culture. This study investigated the effects of past viewing experiences and differences in expressive performance on an audience’s transportive experience into a created world of a storytelling performance. In the experiment, 60 participants (mean age = 34.12 years, SD = 13.18 years, range 18–63 years) were assigned to watch one of two videotaped performances that were played (1) in an orthodox way for frequent viewers and (2) in a modified way aimed at easier comprehension for first-time viewers. Eyeblink synchronization among participants was quantified by employing distance-based measurements of spike trains, Dspike and Dinterval (Victor and Purpura, 1997). The results indicated that even non-familiar participants’ eyeblinks were synchronized as the story progressed and that the effect of the viewing experience on transportation was weak. Rather, the results of a multiple regression analysis demonstrated that the degrees of transportation could be predicted by a retrospectively reported humor experience and higher real-time variability (i.e., logarithmic transformed SD) of inter blink intervals during a performance viewing. The results are discussed from the viewpoint in which the extent of eyeblink synchronization and eyeblink-rate variability acts as an index of the inner experience of audience members. PMID:26029123

Sex differences in learning processes of classical and operant conditioning

PubMed Central

Dalla, Christina; Shors, Tracey J.

2009-01-01

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 on 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. PMID:19272397

Sex differences in learning processes of classical and operant conditioning.

PubMed

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.

Galantamine Facilitates Acquisition of Hippocampus-Dependent Trace Eyeblink Conditioning in Aged Rabbits

ERIC Educational Resources Information Center

Weible, Aldis P.; Oh, M. Matthew; Lee, Grace; Disterhoft, John F.

2004-01-01

Cholinergic systems are critical to the neural mechanisms mediating learning. Reduced nicotinic cholinergic receptor (nAChR) binding is a hallmark of normal aging. These reductions are markedly more severe in some dementias, such as Alzheimer's disease. Pharmacological central nervous system therapies are a means to ameliorate the cognitive…

Neuropsychological and neurophysiological benefits from white noise in children with and without ADHD.

PubMed

Baijot, Simon; Slama, Hichem; Söderlund, Göran; Dan, Bernard; Deltenre, Paul; Colin, Cécile; Deconinck, Nicolas

2016-03-15

Optimal stimulation theory and moderate brain arousal (MBA) model hypothesize that extra-task stimulation (e.g. white noise) could improve cognitive functions of children with attention-deficit/hyperactivity disorder (ADHD). We investigate benefits of white noise on attention and inhibition in children with and without ADHD (7-12 years old), both at behavioral and at neurophysiological levels. Thirty children with and without ADHD performed a visual cued Go/Nogo task in two conditions (white noise or no-noise exposure), in which behavioral and P300 (mean amplitudes) data were analyzed. Spontaneous eye-blink rates were also recorded and participants went through neuropsychological assessment. Two separate analyses were conducted with each child separately assigned into two groups (1) ADHD or typically developing children (TDC), and (2) noise beneficiaries or non-beneficiaries according to the observed performance during the experiment. This latest categorization, based on a new index we called "Noise Benefits Index" (NBI), was proposed to determine a neuropsychological profile positively sensitive to noise. Noise exposure reduced omission rate in children with ADHD, who were no longer different from TDC. Eye-blink rate was higher in children with ADHD but was not modulated by white noise. NBI indicated a significant relationship between ADHD and noise benefit. Strong correlations were observed between noise benefit and neuropsychological weaknesses in vigilance and inhibition. Participants who benefited from noise had an increased Go P300 in the noise condition. The improvement of children with ADHD with white noise supports both optimal stimulation theory and MBA model. However, eye-blink rate results question the dopaminergic hypothesis in the latter. The NBI evidenced a profile positively sensitive to noise, related with ADHD, and associated with weaker cognitive control.

Model-Driven Analysis of Eyeblink Classical Conditioning Reveals the Underlying Structure of Cerebellar Plasticity and Neuronal Activity.

PubMed

Antonietti, Alberto; Casellato, Claudia; D'Angelo, Egidio; Pedrocchi, Alessandra

The cerebellum plays a critical role in sensorimotor control. However, how the specific circuits and plastic mechanisms of the cerebellum are engaged in closed-loop processing is still unclear. We developed an artificial sensorimotor control system embedding a detailed spiking cerebellar microcircuit with three bidirectional plasticity sites. This proved able to reproduce a cerebellar-driven associative paradigm, the eyeblink classical conditioning (EBCC), in which a precise time relationship between an unconditioned stimulus (US) and a conditioned stimulus (CS) is established. We challenged the spiking model to fit an experimental data set from human subjects. Two subsequent sessions of EBCC acquisition and extinction were recorded and transcranial magnetic stimulation (TMS) was applied on the cerebellum to alter circuit function and plasticity. Evolutionary algorithms were used to find the near-optimal model parameters to reproduce the behaviors of subjects in the different sessions of the protocol. The main finding is that the optimized cerebellar model was able to learn to anticipate (predict) conditioned responses with accurate timing and success rate, demonstrating fast acquisition, memory stabilization, rapid extinction, and faster reacquisition as in EBCC in humans. The firing of Purkinje cells (PCs) and deep cerebellar nuclei (DCN) changed during learning under the control of synaptic plasticity, which evolved at different rates, with a faster acquisition in the cerebellar cortex than in DCN synapses. Eventually, a reduced PC activity released DCN discharge just after the CS, precisely anticipating the US and causing the eyeblink. Moreover, a specific alteration in cortical plasticity explained the EBCC changes induced by cerebellar TMS in humans. In this paper, for the first time, it is shown how closed-loop simulations, using detailed cerebellar microcircuit models, can be successfully used to fit real experimental data sets. Thus, the changes of the model parameters in the different sessions of the protocol unveil how implicit microcircuit mechanisms can generate normal and altered associative behaviors.The cerebellum plays a critical role in sensorimotor control. However, how the specific circuits and plastic mechanisms of the cerebellum are engaged in closed-loop processing is still unclear. We developed an artificial sensorimotor control system embedding a detailed spiking cerebellar microcircuit with three bidirectional plasticity sites. This proved able to reproduce a cerebellar-driven associative paradigm, the eyeblink classical conditioning (EBCC), in which a precise time relationship between an unconditioned stimulus (US) and a conditioned stimulus (CS) is established. We challenged the spiking model to fit an experimental data set from human subjects. Two subsequent sessions of EBCC acquisition and extinction were recorded and transcranial magnetic stimulation (TMS) was applied on the cerebellum to alter circuit function and plasticity. Evolutionary algorithms were used to find the near-optimal model parameters to reproduce the behaviors of subjects in the different sessions of the protocol. The main finding is that the optimized cerebellar model was able to learn to anticipate (predict) conditioned responses with accurate timing and success rate, demonstrating fast acquisition, memory stabilization, rapid extinction, and faster reacquisition as in EBCC in humans. The firing of Purkinje cells (PCs) and deep cerebellar nuclei (DCN) changed during learning under the control of synaptic plasticity, which evolved at different rates, with a faster acquisition in the cerebellar cortex than in DCN synapses. Eventually, a reduced PC activity released DCN discharge just after the CS, precisely anticipating the US and causing the eyeblink. Moreover, a specific alteration in cortical plasticity explained the EBCC changes induced by cerebellar TMS in humans. In this paper, for the first time, it is shown how closed-loop simulations, using detailed cerebellar microcircuit models, can be successfully used to fit real experimental data sets. Thus, the changes of the model parameters in the different sessions of the protocol unveil how implicit microcircuit mechanisms can generate normal and altered associative behaviors.

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

ERIC Educational Resources Information Center

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…

Reflex Augmentation of a Tap-Elicited Eyeblink: The Effects of Tone Frequency and Tap Intensity.

ERIC Educational Resources Information Center

Cohen, Michelle E.; And Others

1986-01-01

Describes two experiments that examined whether the amplitude of the human eyeblink by a mild tap between the eyebrows can be increased if a brief tone is presented simultaneously with the tap and how these effects change from newborn infants to adults. (HOD)

Cross-modal transfer of the conditioned eyeblink response during interstimulus interval discrimination training in young rats

PubMed Central

Brown, Kevin L.; Stanton, Mark E.

2008-01-01

Eyeblink classical conditioning (EBC) was observed across a broad developmental period with tasks utilizing two interstimulus intervals (ISIs). In ISI discrimination, two distinct conditioned stimuli (CSs; light and tone) are reinforced with a periocular shock unconditioned stimulus (US) at two different CS-US intervals. Temporal uncertainty is identical in design with the exception that the same CS is presented at both intervals. Developmental changes in conditioning have been reported in each task beyond ages when single-ISI learning is well developed. The present study sought to replicate and extend these previous findings by testing each task at four separate ages. Consistent with previous findings, younger rats (postnatal day – PD - 23 and 30) trained in ISI discrimination showed evidence of enhanced cross-modal influence of the short CS-US pairing upon long CS conditioning relative to older subjects. ISI discrimination training at PD43-47 yielded outcomes similar to those in adults (PD65-71). Cross-modal transfer effects in this task therefore appear to diminish between PD30 and PD43-47. Comparisons of ISI discrimination with temporal uncertainty indicated that cross-modal transfer in ISI discrimination at the youngest ages did not represent complete generalization across CSs. ISI discrimination undergoes a more protracted developmental emergence than single-cue EBC and may be a more sensitive indicator of developmental disorders involving cerebellar dysfunction. PMID:18726989

Modeling startle eyeblink electromyogram to assess fear learning.

PubMed

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.

Effect of Suppression, Reappraisal, and Acceptance of Emotional Pictures on Acoustic Eye-Blink Startle Magnitude

PubMed Central

Asnaani, Anu; Sawyer, Alice T.; Aderka, Idan M.; Hofmann, Stefan G.

2012-01-01

To examine the effects of different emotion regulation strategies on acoustic eye-blink startle, 65 participants viewed positive, neutral, and negative pictures and were instructed to suppress, reappraise, or accept their emotional responses to these pictures using a within-group experimental design with separate blocks of pictures for each strategy. Instructions to suppress the emotional response led to an attenuation of the eye-blink startle magnitude, in comparison with instructions to reappraise or accept. Reappraisal and acceptance instructions did not differ from one another in their effect on startle. These results are discussed within the context of the existing empirical literature on emotion regulation. PMID:24551448

Prefrontal oxygenation and the acoustic startle eyeblink response during exercise: A test of the dual-mode model.

PubMed

Tempest, Gavin D; Parfitt, Gaynor

2017-07-01

The interplay between the prefrontal cortex and amygdala is proposed to explain the regulation of affective responses (pleasure/displeasure) during exercise as outlined in the dual-mode model. However, due to methodological limitations the dual-mode model has not been fully tested. In this study, prefrontal oxygenation (using near-infrared spectroscopy) and amygdala activity (reflected by eyeblink amplitude using acoustic startle methodology) were recorded during exercise standardized to metabolic processes: 80% of ventilatory threshold (below VT), at the VT, and at the respiratory compensation point (RCP). Self-reported tolerance of the intensity of exercise was assessed prior to, and affective responses recorded during exercise. The results revealed that, as the intensity of exercise became more challenging (from below VT to RCP), prefrontal oxygenation was larger and eyeblink amplitude and affective responses were reduced. Below VT and at VT, larger prefrontal oxygenation was associated with larger eyeblink amplitude. At the RCP, prefrontal oxygenation was greater in the left than right hemisphere, and eyeblink amplitude explained significant variance in affective responses (with prefrontal oxygenation) and self-reported tolerance. These findings highlight the role of the prefrontal cortex and potentially the amygdala in the regulation of affective (particularly negative) responses during exercise at physiologically challenging intensities (above VT). In addition, a psychophysiological basis of self-reported tolerance is indicated. This study provides some support of the dual-mode model and insight into the neural basis of affective responses during exercise. © 2017 Society for Psychophysiological Research.

Electrical stimulation of the rostral medial prefrontal cortex in rabbits inhibits the expression of conditioned eyelid responses but not their acquisition

PubMed Central

Leal-Campanario, Rocío; Fairén, Alfonso; Delgado-García, José M.; Gruart, Agnès

2007-01-01

We have studied the role of rostral medial prefrontal cortex (mPFC) on reflexively evoked blinks and on classically conditioned eyelid responses in alert-behaving rabbits. The rostral mPFC was identified by its afferent projections from the medial half of the thalamic mediodorsal nuclear complex. Classical conditioning consisted of a delay paradigm using a 370-ms tone as the conditioned stimulus (CS) and a 100-ms air puff directed at the left cornea as the unconditioned stimulus (US). The CS coterminated with the US. Electrical train stimulation of the contralateral rostral mPFC produced a significant inhibition of air-puff-evoked blinks. The same train stimulation of the rostral mPFC presented during the CS–US interval for 10 successive conditioning sessions significantly reduced the generation of conditioned responses (CRs) as compared with values reached by control animals. Interestingly, the percentage of CRs almost reached control values when train stimulation of the rostral mPFC was removed from the fifth conditioning session on. The electrical stimulation of the rostral mPFC in well conditioned animals produced a significant decrease in the percentage of CRs. Moreover, the stimulation of the rostral mPFC was also able to modify the kinematics (latency, amplitude, and velocity) of evoked CRs. These results suggest that the rostral mPFC is a potent inhibitor of reflexively evoked and classically conditioned eyeblinks but that activation prevents only the expression of CRs, not their latent acquisition. Functional and behavioral implications of this inhibitory role of the rostral mPFC are discussed. PMID:17592148

Theta synchronization between medial prefrontal cortex and cerebellum is associated with adaptive performance of associative learning behavior

PubMed Central

Chen, Hao; Wang, Yi-jie; Yang, Li; Sui, Jian-feng; Hu, Zhi-an; Hu, Bo

2016-01-01

Associative learning is thought to require coordinated activities among distributed brain regions. For example, to direct behavior appropriately, the medial prefrontal cortex (mPFC) must encode and maintain sensory information and then interact with the cerebellum during trace eyeblink conditioning (TEBC), a commonly-used associative learning model. However, the mechanisms by which these two distant areas interact remain elusive. By simultaneously recording local field potential (LFP) signals from the mPFC and the cerebellum in guinea pigs undergoing TEBC, we found that theta-frequency (5.0–12.0 Hz) oscillations in the mPFC and the cerebellum became strongly synchronized following presentation of auditory conditioned stimulus. Intriguingly, the conditioned eyeblink response (CR) with adaptive timing occurred preferentially in the trials where mPFC-cerebellum theta coherence was stronger. Moreover, both the mPFC-cerebellum theta coherence and the adaptive CR performance were impaired after the disruption of endogenous orexins in the cerebellum. Finally, association of the mPFC -cerebellum theta coherence with adaptive CR performance was time-limited occurring in the early stage of associative learning. These findings suggest that the mPFC and the cerebellum may act together to contribute to the adaptive performance of associative learning behavior by means of theta synchronization. PMID:26879632

Individual Differences in Cognitive-Flexibility: The Influence of Spontaneous Eyeblink Rate, Trait Psychoticism and Working Memory on Attentional Set-Shifting

ERIC Educational Resources Information Center

Tharp, Ian J.; Pickering, Alan D.

2011-01-01

Individual differences in psychophysiological function have been shown to influence the balance between flexibility and distractibility during attentional set-shifting [e.g., Dreisbach et al. (2005). Dopamine and cognitive control: The influence of spontaneous eyeblink rate and dopamine gene polymorphisms on perseveration and distractibility.…

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

ERIC Educational Resources Information Center

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…

Effects of meditation practice on spontaneous eyeblink rate.

PubMed

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. © 2016 Society for Psychophysiological Research.

Changes in the magnitude of the eyeblink startle response during habituation of sexual arousal.

PubMed

Koukounas, E; Over, R

2000-06-01

Modulation of the startle response was used to examine emotional processing of sexual stimulation across trials within a session. Eyeblink startle was elicited by a probe (burst of intense white noise) presented intermittently while men were viewing an erotic film segment. Repeated display of the film segment resulted in a progressive decrease in sexual arousal. Habituation of sexual arousal was accompanied by a reduction over trials in the extent the men felt absorbed when viewing the erotic stimulus and by an increase over trials in the magnitude of the eyeblink startle response. Replacing the familiar stimulus by a novel erotic stimulus increased in sexual arousal and absorption and reduced startle (novelty effect), while dishabituation was evident for all three response measures when the familiar stimulus was reintroduced. This pattern of results indicates that with repeated presentation an erotic stimulus is experienced not only as less sexually arousing but also as less appetitive and absorbing. The question of whether habituation of sexual arousal is mediated by changes in attentional and affective processing over trials is discussed, as are clinical contexts in which eyeblink startle can be used in studying aspects of sexual functioning.

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

ERIC Educational Resources Information Center

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,…

Differing Presynaptic Contributions to LTP and Associative Learning in Behaving Mice

PubMed Central

Madroñal, Noelia; Gruart, Agnès; Delgado-García, José M.

2009-01-01

The hippocampal CA3-CA1 synapse is an excellent experimental model for studying the interactions between short- and long-term plastic changes taking place following high-frequency stimulation (HFS) of Schaffer collaterals and during the acquisition and extinction of a classical eyeblink conditioning in behaving mice. Input/output curves and a full-range paired-pulse study enabled determining the optimal intensities and inter-stimulus intervals for evoking paired-pulse facilitation (PPF) or depression (PPD) at the CA3-CA1 synapse. Long-term potentiation (LTP) induced by HFS lasted ≈10 days. HFS-induced LTP evoked an initial depression of basal PPF. Recovery of PPF baseline values was a steady and progressive process lasting ≈20 days, i.e., longer than the total duration of the LTP. In a subsequent series of experiments, we checked whether PPF was affected similarly during activity-dependent synaptic changes. Animals were conditioned using a trace paradigm, with a tone as a conditioned stimulus (CS) and an electrical shock to the trigeminal nerve as an unconditioned stimulus (US). A pair of pulses (40 ms interval) was presented to the Schaffer collateral-commissural pathway to evoke field EPSPs (fEPSPs) during the CS-US interval. Basal PPF decreased steadily across conditioning sessions (i.e., in the opposite direction to that during LTP), reaching a minimum value during the 10th conditioning session. Thus, LTP and classical eyeblink conditioning share some presynaptic mechanisms, but with an opposite evolution. Furthermore, PPF and PPD might play a homeostatic role during long-term plastic changes at the CA3-CA1 synapse. PMID:19636387

The Use of Trace Eyeblink Classical Conditioning to Assess Hippocampal Dysfunction in a Rat Model of Fetal Alcohol Spectrum Disorders

PubMed Central

Tran, Tuan D.; Amin, Aenia; Jones, Keith G.; Sheffer, Ellen M.; Ortega, Lidia; Dolman, Keith

2017-01-01

Neonatal rats were administered a relatively high concentration of ethyl alcohol (11.9% v/v) during postnatal days 4-9, a time when the fetal brain undergoes rapid organizational change and is similar to accelerated brain changes that occur during the third trimester in humans. This model of fetal alcohol spectrum disorders (FASDs) produces severe brain damage, mimicking the amount and pattern of binge-drinking that occurs in some pregnant alcoholic mothers. We describe the use of trace eyeblink classical conditioning (ECC), a higher-order variant of associative learning, to assess long-term hippocampal dysfunction that is typically seen in alcohol-exposed adult offspring. At 90 days of age, rodents were surgically prepared with recording and stimulating electrodes, which measured electromyographic (EMG) blink activity from the left eyelid muscle and delivered mild shock posterior to the left eye, respectively. After a 5 day recovery period, they underwent 6 sessions of trace ECC to determine associative learning differences between alcohol-exposed and control rats. Trace ECC is one of many possible ECC procedures that can be easily modified using the same equipment and software, so that different neural systems can be assessed. ECC procedures in general, can be used as diagnostic tools for detecting neural pathology in different brain systems and different conditions that insult the brain. PMID:28809846

The effect of panic disorder versus anxiety sensitivity on event-related potentials during anticipation of threat.

PubMed

Stevens, Elizabeth S; Weinberg, Anna; Nelson, Brady D; Meissel, Emily E E; Shankman, Stewart A

2018-03-01

Attention-related abnormalities are key components of the abnormal defensive responding observed in panic disorder (PD). Although behavioral studies have found aberrant attentional biases towards threat in PD, psychophysiological studies have been mixed. Predictability of threat, an important feature of threat processing, may have contributed to these mixed findings. Additionally, anxiety sensitivity, a dimensional trait associated with PD, may yield stronger associations with cognitive processes than categorical diagnoses of PD. In this study, 171 participants with PD and/or depression and healthy controls completed a task that differentiated anticipation of predictable vs. unpredictable shocks, while startle eyeblink and event-related potentials (ERPs [N100, P300]) were recorded. In all participants, relative to the control condition, probe N100 was enhanced to both predictable and unpredictable threat, whereas P300 suppression was unique to predictable threat. Probe N100, but not P300, was associated with startle eyeblink during both threatening conditions, and was strongest for unpredictable threat. PD was not associated with ERPs, but anxiety sensitivity (physical concerns) was positively associated with probe N100 (indicating reduced responding) in the unpredictable condition independent of PD diagnosis. Vulnerability to panic-related psychopathology may be characterized by aberrant early processing of threat, which may be especially evident during anticipation of unpredictable threats. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed Central

PONTIFEX, MATTHEW B.; GWIZDALA, KATHRYN L.; PARKS, ANDREW C.; BILLINGER, MARTIN; BRUNNER, CLEMENS

2017-01-01

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. PMID:28026876

A new ICA-based fingerprint method for the automatic removal of physiological artifacts from EEG recordings.

PubMed

Tamburro, Gabriella; Fiedler, Patrique; Stone, David; Haueisen, Jens; Comani, Silvia

2018-01-01

EEG may be affected by artefacts hindering the analysis of brain signals. Data-driven methods like independent component analysis (ICA) are successful approaches to remove artefacts from the EEG. However, the ICA-based methods developed so far are often affected by limitations, such as: the need for visual inspection of the separated independent components (subjectivity problem) and, in some cases, for the independent and simultaneous recording of the inspected artefacts to identify the artefactual independent components; a potentially heavy manipulation of the EEG signals; the use of linear classification methods; the use of simulated artefacts to validate the methods; no testing in dry electrode or high-density EEG datasets; applications limited to specific conditions and electrode layouts. Our fingerprint method automatically identifies EEG ICs containing eyeblinks, eye movements, myogenic artefacts and cardiac interference by evaluating 14 temporal, spatial, spectral, and statistical features composing the IC fingerprint. Sixty-two real EEG datasets containing cued artefacts are recorded with wet and dry electrodes (128 wet and 97 dry channels). For each artefact, 10 nonlinear SVM classifiers are trained on fingerprints of expert-classified ICs. Training groups include randomly chosen wet and dry datasets decomposed in 80 ICs. The classifiers are tested on the IC-fingerprints of different datasets decomposed into 20, 50, or 80 ICs. The SVM performance is assessed in terms of accuracy, False Omission Rate (FOR), Hit Rate (HR), False Alarm Rate (FAR), and sensitivity ( p ). For each artefact, the quality of the artefact-free EEG reconstructed using the classification of the best SVM is assessed by visual inspection and SNR. The best SVM classifier for each artefact type achieved average accuracy of 1 (eyeblink), 0.98 (cardiac interference), and 0.97 (eye movement and myogenic artefact). Average classification sensitivity (p) was 1 (eyeblink), 0.997 (myogenic artefact), 0.98 (eye movement), and 0.48 (cardiac interference). Average artefact reduction ranged from a maximum of 82% for eyeblinks to a minimum of 33% for cardiac interference, depending on the effectiveness of the proposed method and the amplitude of the removed artefact. The performance of the SVM classifiers did not depend on the electrode type, whereas it was better for lower decomposition levels (50 and 20 ICs). Apart from cardiac interference, SVM performance and average artefact reduction indicate that the fingerprint method has an excellent overall performance in the automatic detection of eyeblinks, eye movements and myogenic artefacts, which is comparable to that of existing methods. Being also independent from simultaneous artefact recording, electrode number, type and layout, and decomposition level, the proposed fingerprint method can have useful applications in clinical and experimental EEG settings.

A new ICA-based fingerprint method for the automatic removal of physiological artifacts from EEG recordings

PubMed Central

Tamburro, Gabriella; Fiedler, Patrique; Stone, David; Haueisen, Jens

2018-01-01

Background EEG may be affected by artefacts hindering the analysis of brain signals. Data-driven methods like independent component analysis (ICA) are successful approaches to remove artefacts from the EEG. However, the ICA-based methods developed so far are often affected by limitations, such as: the need for visual inspection of the separated independent components (subjectivity problem) and, in some cases, for the independent and simultaneous recording of the inspected artefacts to identify the artefactual independent components; a potentially heavy manipulation of the EEG signals; the use of linear classification methods; the use of simulated artefacts to validate the methods; no testing in dry electrode or high-density EEG datasets; applications limited to specific conditions and electrode layouts. Methods Our fingerprint method automatically identifies EEG ICs containing eyeblinks, eye movements, myogenic artefacts and cardiac interference by evaluating 14 temporal, spatial, spectral, and statistical features composing the IC fingerprint. Sixty-two real EEG datasets containing cued artefacts are recorded with wet and dry electrodes (128 wet and 97 dry channels). For each artefact, 10 nonlinear SVM classifiers are trained on fingerprints of expert-classified ICs. Training groups include randomly chosen wet and dry datasets decomposed in 80 ICs. The classifiers are tested on the IC-fingerprints of different datasets decomposed into 20, 50, or 80 ICs. The SVM performance is assessed in terms of accuracy, False Omission Rate (FOR), Hit Rate (HR), False Alarm Rate (FAR), and sensitivity (p). For each artefact, the quality of the artefact-free EEG reconstructed using the classification of the best SVM is assessed by visual inspection and SNR. Results The best SVM classifier for each artefact type achieved average accuracy of 1 (eyeblink), 0.98 (cardiac interference), and 0.97 (eye movement and myogenic artefact). Average classification sensitivity (p) was 1 (eyeblink), 0.997 (myogenic artefact), 0.98 (eye movement), and 0.48 (cardiac interference). Average artefact reduction ranged from a maximum of 82% for eyeblinks to a minimum of 33% for cardiac interference, depending on the effectiveness of the proposed method and the amplitude of the removed artefact. The performance of the SVM classifiers did not depend on the electrode type, whereas it was better for lower decomposition levels (50 and 20 ICs). Discussion Apart from cardiac interference, SVM performance and average artefact reduction indicate that the fingerprint method has an excellent overall performance in the automatic detection of eyeblinks, eye movements and myogenic artefacts, which is comparable to that of existing methods. Being also independent from simultaneous artefact recording, electrode number, type and layout, and decomposition level, the proposed fingerprint method can have useful applications in clinical and experimental EEG settings. PMID:29492336

Defensive Physiological Reactions to Rejection

PubMed Central

Gyurak, Anett; Ayduk, Özlem

2014-01-01

We examined the hypothesis that rejection automatically elicits defensive physiological reactions in people with low self-esteem (SE) but that attentional control moderates this effect. Undergraduates (N = 67) completed questionnaire measures of SE and attentional control. Their eye-blink responses to startle probes were measured while they viewed paintings related to rejection and acceptance themes. The stimuli also included positive-, negative-, and neutral-valence control paintings unrelated to rejection. As predicted, compared with people high in SE, those low in SE showed stronger startle eye-blink responses to paintings related to rejection, but not to negative paintings. Paintings related to acceptance did not attenuate their physiological reactivity. Furthermore, attentional control moderated their sensitivity to rejection, such that low SE was related to greater eye-blink responses to rejection only among individuals who were low in attentional control. Implications of the role of attentional control as a top-down process regulating emotional reactivity in people with low SE are discussed. PMID:17894606

Role of Reuniens Nucleus Projections to the Medial Prefrontal Cortex and to the Hippocampal Pyramidal CA1 Area in Associative Learning

PubMed Central

Eleore, Lyndell; López-Ramos, Juan Carlos; Guerra-Narbona, Rafael; Delgado-García, José M.

2011-01-01

We studied the interactions between short- and long-term plastic changes taking place during the acquisition of a classical eyeblink conditioning and following high-frequency stimulation (HFS) of the reuniens nucleus in behaving mice. Synaptic changes in strength were studied at the reuniens-medial prefrontal cortex (mPFC) and the reuniens-CA1 synapses. Input/output curves and a paired-pulse study enabled determining the functional capabilities of the two synapses and the optimal intensities to be applied at the reuniens nucleus during classical eyeblink conditioning and for HFS applied to the reuniens nucleus. Animals were conditioned using a trace paradigm, with a tone as conditioned stimulus (CS) and an electric shock to the trigeminal nerve as unconditioned stimulus (US). A single pulse was presented to the reuniens nucleus to evoke field EPSPs (fEPSPs) in mPFC and CA1 areas during the CS-US interval. No significant changes in synaptic strength were observed at the reuniens-mPFC and reuniens-CA1 synapses during the acquisition of eyelid conditioned responses (CRs). Two successive HFS sessions carried out during the first two conditioning days decreased the percentage of CRs, without evoking any long-term potentiation (LTP) at the recording sites. HFS of the reuniens nucleus also prevented the proper acquisition of an object discrimination task. A subsequent study revealed that HFS of the reuniens nucleus evoked a significant decrease of paired-pulse facilitation. In conclusion, reuniens nucleus projections to prefrontal and hippocampal circuits seem to participate in the acquisition of associative learning through a mechanism that does not required the development of LTP. PMID:21858159

A train of electrical pulses applied to the primary auditory cortex evokes a conditioned response in guinea pigs.

PubMed

Okuda, Yuji; Shikata, Hiroshi; Song, Wen-Jie

2011-09-01

As a step to develop auditory prosthesis by cortical stimulation, we tested whether a single train of pulses applied to the primary auditory cortex could elicit classically conditioned behavior in guinea pigs. Animals were trained using a tone as the conditioned stimulus and an electrical shock to the right eyelid as the unconditioned stimulus. After conditioning, a train of 11 pulses applied to the left AI induced the conditioned eye-blink response. Cortical stimulation induced no response after extinction. Our results support the feasibility of auditory prosthesis by electrical stimulation of the cortex. Copyright © 2011 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

All in the blink of an eye: new insight into cerebellar and brainstem function in DYT1 and DYT6 dystonia.

PubMed

Sadnicka, A; Teo, J T; Kojovic, M; Pareés, I; Saifee, T A; Kassavetis, P; Schwingenschuh, P; Katschnig-Winter, P; Stamelou, M; Mencacci, N E; Rothwell, J C; Edwards, M J; Bhatia, K P

2015-05-01

Traditionally dystonia has been considered a disorder of basal ganglia dysfunction. However, recent research has advocated a more complex neuroanatomical network. In particular, there is increasing interest in the pathophysiological role of the cerebellum. Patients with cervical and focal hand dystonia have impaired cerebellar associative learning using the paradigm eyeblink conditioning. This is perhaps the most direct evidence to date that the cerebellum is implicated in patients. Eleven patients with DYT1 dystonia and five patients with DYT6 dystonia were examined and rates of eyeblink conditioning were compared with age-matched controls. A marker of brainstem excitability, the blink reflex recovery, was also studied in the same groups. Patients with DYT1 and DYT6 dystonia have a normal ability to acquire conditioned responses. Blink reflex recovery was enhanced in DYT1 but this effect was not seen in DYT6. If the cerebellum is an important driver in DYT1 and DYT6 dystonia our data suggest that there is specific cerebellar dysfunction such that the circuits essential for conditioning function normally. Our data are contrary to observations in focal dystonia and suggest that the cerebellum may have a distinct role in different subsets of dystonia. Evidence of enhanced blink reflex recovery in all patients with dystonia was not found and recent studies calling for the blink recovery reflex to be used as a diagnostic test for dystonic tremor may require further corroboration. © 2014 The Author(s) European Journal of Neurology © 2014 EAN.

Automatic removal of eye-movement and blink artifacts from EEG signals.

PubMed

Gao, Jun Feng; Yang, Yong; Lin, Pan; Wang, Pei; Zheng, Chong Xun

2010-03-01

Frequent occurrence of electrooculography (EOG) artifacts leads to serious problems in interpreting and analyzing the electroencephalogram (EEG). In this paper, a robust method is presented to automatically eliminate eye-movement and eye-blink artifacts from EEG signals. Independent Component Analysis (ICA) is used to decompose EEG signals into independent components. Moreover, the features of topographies and power spectral densities of those components are extracted to identify eye-movement artifact components, and a support vector machine (SVM) classifier is adopted because it has higher performance than several other classifiers. The classification results show that feature-extraction methods are unsuitable for identifying eye-blink artifact components, and then a novel peak detection algorithm of independent component (PDAIC) is proposed to identify eye-blink artifact components. Finally, the artifact removal method proposed here is evaluated by the comparisons of EEG data before and after artifact removal. The results indicate that the method proposed could remove EOG artifacts effectively from EEG signals with little distortion of the underlying brain signals.

Eyeblink conditioning in unmedicated schizophrenia patients: A positron emission tomography study

PubMed Central

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

2014-01-01

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 O15 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. PMID:24090512

Disrupted sensory gating in pathological gambling.

PubMed

Stojanov, Wendy; Karayanidis, Frini; Johnston, Patrick; Bailey, Andrew; Carr, Vaughan; Schall, Ulrich

2003-08-15

Some neurochemical evidence as well as recent studies on molecular genetics suggest that pathologic gambling may be related to dysregulated dopamine neurotransmission. The current study examined sensory (motor) gating in pathologic gamblers as a putative measure of endogenous brain dopamine activity with prepulse inhibition of the acoustic startle eye-blink response and the auditory P300 event-related potential. Seventeen pathologic gamblers and 21 age- and gender-matched healthy control subjects were assessed. Both prepulse inhibition measures were recorded under passive listening and two-tone prepulse discrimination conditions. Compared to the control group, pathologic gamblers exhibited disrupted sensory (motor) gating on all measures of prepulse inhibition. Sensory motor gating deficits of eye-blink responses were most profound at 120-millisecond prepulse lead intervals in the passive listening task and at 240-millisecond prepulse lead intervals in the two-tone prepulse discrimination task. Sensory gating of P300 was also impaired in pathologic gamblers, particularly at 500-millisecond lead intervals, when performing the discrimination task on the prepulse. In the context of preclinical studies on the disruptive effects of dopamine agonists on prepulse inhibition, our findings suggest increased endogenous brain dopamine activity in pathologic gambling in line with previous neurobiological findings.

Neuronal Correlates of Cross-Modal Transfer in the Cerebellum and Pontine Nuclei

PubMed Central

Campolattaro, Matthew M.; Kashef, Alireza; Lee, Inah; Freeman, John H.

2011-01-01

Cross-modal transfer occurs when learning established with a stimulus from one sensory modality facilitates subsequent learning with a new stimulus from a different sensory modality. The current study examined neuronal correlates of cross-modal transfer of Pavlovian eyeblink conditioning in rats. Neuronal activity was recorded from tetrodes within the anterior interpositus nucleus (IPN) of the cerebellum and basilar pontine nucleus (PN) during different phases of training. After stimulus pre-exposure and unpaired training sessions with a tone conditioned stimulus (CS), light CS, and periorbital stimulation unconditioned stimulus (US), rats received associative training with one of the CSs and the US (CS1-US). Training then continued on the same day with the other CS to assess cross-modal transfer (CS2-US). The final training session included associative training with both CSs on separate trials to establish stronger cross-modal transfer (CS1/CS2). Neurons in the IPN and PN showed primarily unimodal responses during pre-training sessions. Learning-related facilitation of activity correlated with the conditioned response (CR) developed in the IPN and PN during CS1-US training. Subsequent CS2-US training resulted in acquisition of CRs and learning-related neuronal activity in the IPN but substantially less little learning-related activity in the PN. Additional CS1/CS2 training increased CRs and learning-related activity in the IPN and PN during CS2-US trials. The findings suggest that cross-modal neuronal plasticity in the PN is driven by excitatory feedback from the IPN to the PN. Interacting plasticity mechanisms in the IPN and PN may underlie behavioral cross-modal transfer in eyeblink conditioning. PMID:21411647

Time-dependent reorganization of the brain components underlying memory retention in trace eyeblink conditioning.

PubMed

Takehara, Kaori; Kawahara, Shigenori; Kirino, Yutaka

2003-10-29

Many studies have confirmed the time-limited involvement of the hippocampus in mnemonic processes and suggested that there is reorganization of the responsible brain circuitry during memory consolidation. To clarify such reorganization, we chose trace classical eyeblink conditioning, in which hippocampal ablation produces temporally graded retrograde amnesia. Here, we extended the temporal characterization of retrograde amnesia to other regions that are involved in acquisition during this task: the medial prefrontal cortex (mPFC) and the cerebellum. At a various time interval after establishing the trace conditioned response (CR), rats received an aspiration of one of the three regions. After recovery, the animals were tested for their CR retention. When ablated 1 d after the learning, both the hippocampal lesion and the cerebellar lesion group of rats exhibited a severe impairment in retention of the CR, whereas the mPFC lesion group showed only a slight decline. With an increase in interval between the lesion and the learning, the effect of the hippocampal lesion diminished and that of the mPFC lesion increased. When ablated 4 weeks after the learning, the hippocampal lesion group exhibited as robust CRs as its corresponding control group. In contrast, the mPFC lesion and the cerebellar lesion groups failed to retain the CRs. These results indicate that the hippocampus and the cerebellum, but only marginally the mPFC, constitute a brain circuitry that mediates recently acquired memory. As time elapses, the circuitry is reorganized to use mainly the mPFC and the cerebellum, but not the hippocampus, for remotely acquired memory.

Data on amyloid precursor protein accumulation, spontaneous physical activity, and motor learning after traumatic brain injury in the triple-transgenic mouse model of Alzheimer׳s disease.

PubMed

Kishimoto, Yasushi; Shishido, Hajime; Sawanishi, Mayumi; Toyota, Yasunori; Ueno, Masaki; Kubota, Takashi; Kirino, Yutaka; Tamiya, Takashi; Kawai, Nobuyuki

2016-12-01

This data article contains supporting information regarding the research article entitled "Traumatic brain injury accelerates amyloid-β deposition and impairs spatial learning in the triple-transgenic mouse model of Alzheimer׳s disease" (H. Shishido, Y. Kishimoto, N. Kawai, Y. Toyota, M. Ueno, T. Kubota, Y. Kirino, T. Tamiya, 2016) [1]. Triple-transgenic (3×Tg)-Alzheimer׳s disease (AD) model mice exhibited significantly poorer spatial learning than sham-treated 3×Tg-AD mice 28 days after traumatic brain injury (TBI). Correspondingly, amyloid-β (Aβ) deposition within the hippocampus was significantly greater in 3×Tg-AD mice 28 days after TBI. However, data regarding the short-term and long-term influences of TBI on amyloid precursor protein (APP) accumulation in AD model mice remain limited. Furthermore, there is little data showing whether physical activity and motor learning are affected by TBI in AD model mice. Here, we provide immunocytochemistry data confirming that TBI induces significant increases in APP accumulation in 3×Tg-AD mice at both 7 days and 28 days after TBI. Furthermore, 3×Tg-AD model mice exhibit a reduced ability to acquire conditioned responses (CRs) during delay eyeblink conditioning compared to sham-treated 3×Tg-AD model mice 28 days after TBI. However, physical activity and motor performance are not significantly changed in TBI-treated 3×Tg-AD model mice.

Effects of anxiety sensitivity and expectations on the modulation of the startle eyeblink response during a caffeine challenge.

PubMed

Benke, Christoph; Blumenthal, Terry D; Modeß, Christiane; Hamm, Alfons O; Pané-Farré, Christiane A

2015-09-01

The way in which the tendency to fear somatic arousal sensations (anxiety sensitivity), in interaction with the created expectations regarding arousal induction, might affect defensive responding to a symptom provocation challenge is not yet understood. The present study investigated the effect of anxiety sensitivity on autonomic arousal, startle eyeblink responses, and reported arousal and alertness to expected vs. unexpected caffeine consumption. To create a match/mismatch of expected and experienced arousal, high and low anxiety sensitive participants received caffeine vs. no drug either mixed in coffee (expectation of arousal induction) or in bitter lemon soda (no expectation of arousal induction) on four separate occasions. Autonomic arousal (heart rate, skin conductance level), respiration (end-tidal CO2, minute ventilation), defensive reflex responses (startle eyeblink), and reported arousal and alertness were recorded prior to, immediately and 30 min after beverage ingestion. Caffeine increased ventilation, autonomic arousal, and startle response magnitudes. Both groups showed comparable levels of autonomic and respiratory responses. The startle eyeblink responses were decreased when caffeine-induced arousal occurred unexpectedly, e.g., after administering caffeine in bitter lemon. This effect was more accentuated in high anxiety sensitive persons. Moreover, in high anxiety sensitive persons, the expectation of arousal (coffee consumption) led to higher subjective alertness when administering caffeine and increased arousal even if no drug was consumed. Unexpected symptom provocation leads to increased attention allocation toward feared arousal sensations in high anxiety sensitive persons. This finding broadens our understanding of modulatory mechanisms in defensive responding to bodily symptoms.

Lead exposure and fear-potentiated startle in the VA Normative Aging Study: a pilot study of a novel physiological approach to investigating neurotoxicant effects.

PubMed

Grashow, Rachel; Miller, Mark W; McKinney, Ann; Nie, Linda H; Sparrow, David; Hu, Howard; Weisskopf, Marc G

2013-01-01

Physiologically-based indicators of neural plasticity in humans could provide mechanistic insights into toxicant actions on learning in the brain, and perhaps prove more objective and sensitive measures of such effects than other methods. We explored the association between lead exposure and classical conditioning of the acoustic startle reflex (ASR)-a simple form of associative learning in the brain-in a population of elderly men. Fifty-one men from the VA Normative Aging Study with cumulative bone lead exposure measurements made with K-X-Ray-Fluorescence participated in a fear-conditioning protocol. The mean age of the men was 75.5years (standard deviation [sd]=5.9) and mean patella lead concentration was 22.7μg/g bone (sd=15.9). Baseline ASR eyeblink response decreased with age, but was not associated with subsequent conditioning. Among 37 men with valid responses at the end of the protocol, higher patella lead was associated with decreased awareness of the conditioning contingency (declarative learning; adjusted odds ratio [OR] per 20μg/g patella lead=0.91, 95% confidence interval [CI]: 0.84, 0.99, p=0.03). Eyeblink conditioning (non-declarative learning) was 0.44sd less (95% CI: -0.91, 0.02; p=0.06) per 20μg/g patella lead after adjustment. Each result was stronger when correcting for the interval between lead measurement and startle testing (awareness: OR=0.88, 95% CI: 0.78, 0.99, p=0.04; conditioning: -0.79sd less, 95% CI: -1.56, 0.03, p=0.04). This initial exploration suggests that lead exposure interferes with specific neural mechanisms of learning and offers the possibility that the ASR may provide a new approach to physiologically explore the effects of neurotoxicant exposures on neural mechanisms of learning in humans with a paradigm that is directly comparable to animal models. Copyright © 2013 Elsevier Inc. All rights reserved.

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

PubMed

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. © 2013 Elsevier Ireland Ltd. All rights reserved.

Hypnotizability, Hypnosis and Prepulse Inhibition of the Startle Reflex in Healthy Women: An ERP Analysis

PubMed Central

De Pascalis, Vilfredo; Russo, Emanuela

2013-01-01

A working model of the neurophysiology of hypnosis suggests that highly hypnotizable individuals (HHs) have more effective frontal attentional systems implementing control, monitoring performance, and inhibiting unwanted stimuli from conscious awareness, than low hypnotizable individuals (LHs). Recent studies, using prepulse inhibition (PPI) of the auditory startle reflex (ASR), suggest that HHs, in the waking condition, may show reduced sensory gating although they may selectively attend and disattend different stimuli. Using a within subject design and a strict subject selection procedure, in waking and hypnosis conditions we tested whether HHs compared to LHs showed a significantly lower inhibition of the ASR and startle-related brain activity in both time and intracerebral source localization domains. HHs, as compared to LH participants, exhibited (a) longer latency of the eyeblink startle reflex, (b) reduced N100 responses to startle stimuli, and (c) higher PPI of eyeblink startle and of the P200 and P300 waves. Hypnosis yielded smaller N100 waves to startle stimuli and greater PPI of this component than in the waking condition. sLORETA analysis revealed that, for the N100 (107 msec) elicited during startle trials, HHs had a smaller activation in the left parietal lobe (BA2/40) than LHs. Auditory pulses of pulse-with prepulse trials in HHs yielded less activity of the P300 (280 msec) wave than LHs, in the cingulate and posterior cingulate gyrus (BA23/31). The present results, on the whole, are in the opposite direction to PPI findings on hypnotizability previously reported in the literature. These results provide support to the neuropsychophysiological model that HHs have more effective sensory integration and gating (or filtering) of irrelevant stimuli than LHs. PMID:24278150

Hypnotizability, hypnosis and prepulse inhibition of the startle reflex in healthy women: an ERP analysis.

PubMed

De Pascalis, Vilfredo; Russo, Emanuela

2013-01-01

A working model of the neurophysiology of hypnosis suggests that highly hypnotizable individuals (HHs) have more effective frontal attentional systems implementing control, monitoring performance, and inhibiting unwanted stimuli from conscious awareness, than low hypnotizable individuals (LHs). Recent studies, using prepulse inhibition (PPI) of the auditory startle reflex (ASR), suggest that HHs, in the waking condition, may show reduced sensory gating although they may selectively attend and disattend different stimuli. Using a within subject design and a strict subject selection procedure, in waking and hypnosis conditions we tested whether HHs compared to LHs showed a significantly lower inhibition of the ASR and startle-related brain activity in both time and intracerebral source localization domains. HHs, as compared to LH participants, exhibited (a) longer latency of the eyeblink startle reflex, (b) reduced N100 responses to startle stimuli, and (c) higher PPI of eyeblink startle and of the P200 and P300 waves. Hypnosis yielded smaller N100 waves to startle stimuli and greater PPI of this component than in the waking condition. sLORETA analysis revealed that, for the N100 (107 msec) elicited during startle trials, HHs had a smaller activation in the left parietal lobe (BA2/40) than LHs. Auditory pulses of pulse-with prepulse trials in HHs yielded less activity of the P300 (280 msec) wave than LHs, in the cingulate and posterior cingulate gyrus (BA23/31). The present results, on the whole, are in the opposite direction to PPI findings on hypnotizability previously reported in the literature. These results provide support to the neuropsychophysiological model that HHs have more effective sensory integration and gating (or filtering) of irrelevant stimuli than LHs.

Diffusion Tensor Imaging of the Cerebellum and Eyeblink Conditioning in Fetal Alcohol Spectrum Disorder

PubMed Central

Spottiswoode, B.S.; Meintjes, E.M.; Anderson, A.W.; Molteno, C.D.; Stanton, M.E.; Dodge, N.C.; Gore, J.C.; Peterson, B.S.; Jacobson, J.L.; Jacobson, S.W.

2011-01-01

Background Prenatal alcohol exposure is related to a wide range of neurocognitive effects. Eyeblink conditioning (EBC), which involves temporal pairing of a conditioned with an unconditioned stimulus, has been shown to be a potential biomarker of fetal alcohol exposure. A growing body of evidence suggests that white matter may be a specific target of alcohol teratogenesis, and the neural circuitry underlying EBC is known to involve the cerebellar peduncles. Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique which has proven useful for assessing central nervous system white matter integrity. This study used DTI to examine the degree to which the fetal alcohol-related deficit in EBC may be mediated by structural impairment in the cerebellar peduncles. Methods 13 children with fetal alcohol spectrum disorder (FASD) and 12 matched controls were scanned using DTI and structural MRI sequences. The DTI data were processed using a voxelwise technique, and the structural data were used for volumetric analyses. Prenatal alcohol exposure group and EBC performance were examined in relation to brain volumes and outputs from the DTI analysis. Results FA and perpendicular diffusivity group differences between alcohol-exposed and nonexposed children were identified in the left middle cerebellar peduncle. Alcohol exposure correlated with lower fractional anisotropy (FA) and greater perpendicular diffusivity in this region, and these correlations remained significant even after controlling for total brain and cerebellar volume. Conversely, trace conditioning performance was related to higher FA and lower perpendicular diffusivity in the left middle peduncle. The effect of prenatal alcohol exposure on trace conditioning was partially mediated by lower FA in this region. Conclusions This study extends recent findings that have used DTI to reveal microstructural deficits in white matter in children with FASD. This is the first DTI study to demonstrate mediation of a fetal alcohol-related effect on neuropsychological function by deficits in white matter integrity. PMID:21790667

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

PubMed

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. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Timing and Causality in the Generation of Learned Eyelid Responses

PubMed Central

Sánchez-Campusano, Raudel; Gruart, Agnès; Delgado-García, José M.

2011-01-01

The cerebellum-red nucleus-facial motoneuron (Mn) pathway has been reported as being involved in the proper timing of classically conditioned eyelid responses. This special type of associative learning serves as a model of event timing for studying the role of the cerebellum in dynamic motor control. Here, we have re-analyzed the firing activities of cerebellar posterior interpositus (IP) neurons and orbicularis oculi (OO) Mns in alert behaving cats during classical eyeblink conditioning, using a delay paradigm. The aim was to revisit the hypothesis that the IP neurons (IPns) can be considered a neuronal phase-modulating device supporting OO Mns firing with an emergent timing mechanism and an explicit correlation code during learned eyelid movements. Optimized experimental and computational tools allowed us to determine the different causal relationships (temporal order and correlation code) during and between trials. These intra- and inter-trial timing strategies expanding from sub-second range (millisecond timing) to longer-lasting ranges (interval timing) expanded the functional domain of cerebellar timing beyond motor control. Interestingly, the results supported the above-mentioned hypothesis. The causal inferences were influenced by the precise motor and pre-motor spike timing in the cause-effect interval, and, in addition, the timing of the learned responses depended on cerebellar–Mn network causality. Furthermore, the timing of CRs depended upon the probability of simulated causal conditions in the cause-effect interval and not the mere duration of the inter-stimulus interval. In this work, the close relation between timing and causality was verified. It could thus be concluded that the firing activities of IPns may be related more to the proper performance of ongoing CRs (i.e., the proper timing as a consequence of the pertinent causality) than to their generation and/or initiation. PMID:21941469

Evoking Blinks with Natural Stimulation and Detecting Them with a Noninvasive Optical Device: A Simple, Inexpensive Method for Use with Freely Moving Animals

PubMed Central

Weiss, Craig; Disterhoft, John F.

2008-01-01

Many laboratories studying eyeblinks in unanesthetized rodents use a periorbital shock to evoke the blink. The stimulus is typically delivered via a tether and usually obliterates detection of a full unconditioned response with electromyographic (EMG) recording. Here we describe the adapter we have used successfully for several years to deliver puffs of air to the cornea of freely moving rats during our studies of eyeblink conditioning. The stimulus evokes an unconditioned response that can be recorded without affecting the EMG signal. This allows a complete analysis of the unconditioned response which is important for studies examining reflex modification or the effect of drugs, genetic manipulations, or aging on the unconditioned blink reflex. We also describe an infrared reflective sensor that can be added to the tether to minimize the number of wires that need to be implanted around the eye, and which is relatively immune to electrical artifacts associated with a periorbital shock stimulus or other devices powered by alternating current. The responses recorded simultaneously by EMG wires and the optical sensor appear highly correlated and demonstrate that the optical sensor can measure responses that might otherwise be lost due to electrical interference from a shock stimulus. PMID:18598716

Cerebellar associative sensory learning defects in five mouse autism models

PubMed Central

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

2015-01-01

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

White matter integrity of the cerebellar peduncles as a mediator of effects of prenatal alcohol exposure on eyeblink conditioning

PubMed Central

Fan, Jia; Meintjes, Ernesta M.; Molteno, Christopher D.; Spottiswoode, Bruce S.; Dodge, Neil C.; Alhamud, Alkathafi A.; Stanton, Mark E.; Peterson, Bradley S.; Jacobson, Joseph L.; Jacobson, Sandra W.

2015-01-01

Fetal alcohol spectrum disorders (FASD) are characterized by a range of neurodevelopmental deficits that result from prenatal exposure to alcohol. These can include cognitive, behavioural, and neurological impairment, as well as structural and functional brain damage. Eyeblink conditioning (EBC) is among the most sensitive endpoints affected in FASD. The cerebellar peduncles, large bundles of myelinated nerve fibers that connect the cerebellum to the brainstem, constitute the principal white matter element of the EBC circuit. Diffusion tensor imaging (DTI) is used to assess white matter integrity in fibre pathways linking brain regions. DTI scans of 54 children with FASD and 23 healthy controls, mean age 10.1±1.0 yrs, from the Cape Town Longitudinal Cohort were processed using voxelwise group comparisons. Prenatal alcohol exposure was related to lower fractional anisotropy (FA) bilaterally in the superior cerebellar peduncles and higher mean diffusivity (MD) in the left middle peduncle, effects that remained significant after controlling for potential confounding variables. Lower FA and higher MD in these regions were associated with poorer EBC performance. Moreover, effects of alcohol exposure on EBC decreased significantly after inclusion of these DTI measures in regression models, suggesting that these white matter deficits partially mediate the relation of prenatal alcohol exposure to EBC. The associations of greater alcohol consumption with these DTI measures are largely attributable to greater radial diffusivity, possibly indicating poorer myelination. Thus, these data suggest that fetal alcohol-related deficits in EBC are attributable, in part, to poorer myelination in key regions of the cerebellar peduncles. PMID:25783559

Cerebellar Plasticity and Motor Learning Deficits in a Copy Number Variation Mouse Model of Autism

PubMed Central

Piochon, Claire; Kloth, Alexander D; Grasselli, Giorgio; Titley, Heather K; Nakayama, Hisako; Hashimoto, Kouichi; Wan, Vivian; Simmons, Dana H; Eissa, Tahra; Nakatani, Jin; Cherskov, Adriana; Miyazaki, Taisuke; Watanabe, Masahiko; Takumi, Toru; Kano, Masanobu; Wang, Samuel S-H; Hansel, Christian

2014-01-01

A common feature of autism spectrum disorder (ASD) is the impairment of motor control and learning, occurring in a majority of children with autism, consistent with perturbation in cerebellar function. Here we report alterations in motor behavior and cerebellar synaptic plasticity in a mouse model (patDp/+) for the human 15q11-13 duplication, one of the most frequently observed genetic aberrations in autism. These mice show ASD-resembling social behavior deficits. We find that in patDp/+ mice delay eyeblink conditioning—a form of cerebellum-dependent motor learning—is impaired, and observe deregulation of a putative cellular mechanism for motor learning, long-term depression (LTD) at parallel fiber-Purkinje cell synapses. Moreover, developmental elimination of surplus climbing fibers—a model for activity-dependent synaptic pruning—is impaired. These findings point to deficits in synaptic plasticity and pruning as potential causes for motor problems and abnormal circuit development in autism. PMID:25418414

Phasic and tonic neuron ensemble codes for stimulus-environment conjunctions in the lateral entorhinal cortex.

PubMed

Pilkiw, Maryna; Insel, Nathan; Cui, Younghua; Finney, Caitlin; Morrissey, Mark D; Takehara-Nishiuchi, Kaori

2017-07-06

The lateral entorhinal cortex (LEC) is thought to bind sensory events with the environment where they took place. To compare the relative influence of transient events and temporally stable environmental stimuli on the firing of LEC cells, we recorded neuron spiking patterns in the region during blocks of a trace eyeblink conditioning paradigm performed in two environments and with different conditioning stimuli. Firing rates of some neurons were phasically selective for conditioned stimuli in a way that depended on which room the rat was in; nearly all neurons were tonically selective for environments in a way that depended on which stimuli had been presented in those environments. As rats moved from one environment to another, tonic neuron ensemble activity exhibited prospective information about the conditioned stimulus associated with the environment. Thus, the LEC formed phasic and tonic codes for event-environment associations, thereby accurately differentiating multiple experiences with overlapping features.

Prefrontal control of cerebellum-dependent associative motor learning.

PubMed

Chen, Hao; Yang, Li; Xu, Yan; Wu, Guang-yan; Yao, Juan; Zhang, Jun; Zhu, Zhi-ru; Hu, Zhi-an; Sui, Jian-feng; Hu, Bo

2014-02-01

Behavioral studies have demonstrated that both medial prefrontal cortex (mPFC) and cerebellum play critical roles in trace eyeblink conditioning. However, little is known regarding the mechanism by which the two brain regions interact. By use of electrical stimulation of the caudal mPFC as a conditioned stimulus, we show evidence that persistent outputs from the mPFC to cerebellum are necessary and sufficient for the acquisition and expression of a trace conditioned response (CR)-like response. Specifically, the persistent outputs of caudal mPFC are relayed to the cerebellum via the rostral part of lateral pontine nuclei. Moreover, interfering with persistent activity by blockade of the muscarinic Ach receptor in the caudal mPFC impairs the expression of learned trace CRs. These results suggest an important way for the caudal mPFC to interact with the cerebellum during associative motor learning.

Cerebellar motor learning deficits in medicated and medication-free men with recent-onset schizophrenia

PubMed Central

Coesmans, Michael; Röder, Christian H.; Smit, Albertine E.; Koekkoek, Sebastiaan K.E.; De Zeeuw, Chris I.; Frens, Maarten A.; van der Geest, Josef N.

2014-01-01

Background The notion that cerebellar deficits may underlie clinical symptoms in people with schizophrenia is tested by evaluating 2 forms of cerebellar learning in patients with recent-onset schizophrenia. A potential medication effect is evaluated by including patients with or without antipsychotics. Methods We assessed saccadic eye movement adaptation and eyeblink conditioning in men with recent-onset schizophrenia who were taking antipsychotic medication or who were antipsychotic-free and in age-matched controls. Results We included 39 men with schizophrenia (10 who were taking clozapine, 16 who were taking haloperidol and 13 who were antipsychotic-free) and 29 controls in our study. All participants showed significant saccadic adaptation. Adaptation strength did not differ between healthy controls and men with schizophrenia. The speed of saccade adaptation, however, was significantly lower in men with schizophrenia. They showed a significantly lower increase in the number of conditioned eyeblink responses. Over all experiments, no consistent effects of medication were observed. These outcomes did not correlate with age, years of education, psychopathology or dose of anti psychotics. Limitations As patients were not randomized for treatment, an influence of confounding variables associated with medication status cannot be excluded. Individual patients also varied along the schizophrenia spectrum despite the relative homogeneity with respect to onset of illness and short usage of medication. Finally, the relatively small number of participants may have concealed effects as a result of insufficient statistical power. Conclusion We found several cerebellar learning deficits in men with schizophrenia that we cannot attribute to the use of antipsychotics. Although this finding, combined with the fact that deficits are already present in patients with recent-onset schizophrenia, could suggest that cerebellar impairments are a trait deficit in people with schizophrenia. This should be confirmed in longitudinal studies. PMID:24083457

A Multiple-Plasticity Spiking Neural Network Embedded in a Closed-Loop Control System to Model Cerebellar Pathologies.

PubMed

Geminiani, Alice; Casellato, Claudia; Antonietti, Alberto; D'Angelo, Egidio; Pedrocchi, Alessandra

2018-06-01

The cerebellum plays a crucial role in sensorimotor control and cerebellar disorders compromise adaptation and learning of motor responses. However, the link between alterations at network level and cerebellar dysfunction is still unclear. In principle, this understanding would benefit of the development of an artificial system embedding the salient neuronal and plastic properties of the cerebellum and operating in closed-loop. To this aim, we have exploited a realistic spiking computational model of the cerebellum to analyze the network correlates of cerebellar impairment. The model was modified to reproduce three different damages of the cerebellar cortex: (i) a loss of the main output neurons (Purkinje Cells), (ii) a lesion to the main cerebellar afferents (Mossy Fibers), and (iii) a damage to a major mechanism of synaptic plasticity (Long Term Depression). The modified network models were challenged with an Eye-Blink Classical Conditioning test, a standard learning paradigm used to evaluate cerebellar impairment, in which the outcome was compared to reference results obtained in human or animal experiments. In all cases, the model reproduced the partial and delayed conditioning typical of the pathologies, indicating that an intact cerebellar cortex functionality is required to accelerate learning by transferring acquired information to the cerebellar nuclei. Interestingly, depending on the type of lesion, the redistribution of synaptic plasticity and response timing varied greatly generating specific adaptation patterns. Thus, not only the present work extends the generalization capabilities of the cerebellar spiking model to pathological cases, but also predicts how changes at the neuronal level are distributed across the network, making it usable to infer cerebellar circuit alterations occurring in cerebellar pathologies.

Blink and you’ll miss it: the role of blinking in the perception of magic tricks

PubMed Central

Nakano, Tamami

2016-01-01

Magicians use several techniques to deceive their audiences, including, for example, the misdirection of attention and verbal suggestion. We explored another potential stratagem, namely the relaxation of attention. Participants watched a video of a highly skilled magician whilst having their eye-blinks recorded. The timing of spontaneous eye-blinks was highly synchronized across participants. In addition, the synchronized blinks frequency occurred immediately after a seemingly impossible feat, and often coincided with actions that the magician wanted to conceal from the audience. Given that blinking is associated with the relaxation of attention, these findings suggest that blinking plays an important role in the perception of magic, and that magicians may utilize blinking and the relaxation of attention to hide certain secret actions. PMID:27069808

Blink and you'll miss it: the role of blinking in the perception of magic tricks.

PubMed

Wiseman, Richard J; Nakano, Tamami

2016-01-01

Magicians use several techniques to deceive their audiences, including, for example, the misdirection of attention and verbal suggestion. We explored another potential stratagem, namely the relaxation of attention. Participants watched a video of a highly skilled magician whilst having their eye-blinks recorded. The timing of spontaneous eye-blinks was highly synchronized across participants. In addition, the synchronized blinks frequency occurred immediately after a seemingly impossible feat, and often coincided with actions that the magician wanted to conceal from the audience. Given that blinking is associated with the relaxation of attention, these findings suggest that blinking plays an important role in the perception of magic, and that magicians may utilize blinking and the relaxation of attention to hide certain secret actions.

Are memory traces localized or distributed?

PubMed

Thompson, R F

1991-01-01

Evidence supports the view that "memory traces" are formed in the hippocampus and in the cerebellum in classical conditioning of discrete behavioral responses (e.g. eyeblink conditioning). In the hippocampus, learning results in long-lasting increases in excitability of pyramidal neurons that appear to be localized to these neurons (i.e. changes in membrane properties and receptor function). However, these learning-altered pyramidal neurons are distributed widely throughout CA3 and CA1. Although it plays a key role in certain aspects of classical conditioning, the hippocampus is not necessary for learning and memory of the basic conditioned responses. The cerebellum and its associated brain stem circuitry, on the other hand, does appear to be essential (necessary and sufficient) for learning and memory of the conditioned response. Evidence to date is most consistent with a localized trace in the interpositus nucleus and multiple localized traces in cerebellar cortex, each involving relatively large ensembles of neurons. Perhaps "procedural" memory traces are relatively localized and "declarative" traces more widely distributed.

Phasic and tonic neuron ensemble codes for stimulus-environment conjunctions in the lateral entorhinal cortex

PubMed Central

Pilkiw, Maryna; Insel, Nathan; Cui, Younghua; Finney, Caitlin; Morrissey, Mark D; Takehara-Nishiuchi, Kaori

2017-01-01

The lateral entorhinal cortex (LEC) is thought to bind sensory events with the environment where they took place. To compare the relative influence of transient events and temporally stable environmental stimuli on the firing of LEC cells, we recorded neuron spiking patterns in the region during blocks of a trace eyeblink conditioning paradigm performed in two environments and with different conditioning stimuli. Firing rates of some neurons were phasically selective for conditioned stimuli in a way that depended on which room the rat was in; nearly all neurons were tonically selective for environments in a way that depended on which stimuli had been presented in those environments. As rats moved from one environment to another, tonic neuron ensemble activity exhibited prospective information about the conditioned stimulus associated with the environment. Thus, the LEC formed phasic and tonic codes for event-environment associations, thereby accurately differentiating multiple experiences with overlapping features. DOI: http://dx.doi.org/10.7554/eLife.28611.001 PMID:28682237

The time course of face processing: startle eyeblink response modulation by face gender and expression.

PubMed

Duval, Elizabeth R; Lovelace, Christopher T; Aarant, Justin; Filion, Diane L

2013-12-01

The purpose of this study was to investigate the effects of both facial expression and face gender on startle eyeblink response patterns at varying lead intervals (300, 800, and 3500ms) indicative of attentional and emotional processes. We aimed to determine whether responses to affective faces map onto the Defense Cascade Model (Lang et al., 1997) to better understand the stages of processing during affective face viewing. At 300ms, there was an interaction between face expression and face gender with female happy and neutral faces and male angry faces producing inhibited startle. At 3500ms, there was a trend for facilitated startle during angry compared to neutral faces. These findings suggest that affective expressions are perceived differently in male and female faces, especially at short lead intervals. Future studies investigating face processing should take both face gender and expression into account. © 2013.

Effects of Meditation Practice on Spontaneous Eye Blink Rate

PubMed Central

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

2016-01-01

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 Eye Blink Rates (sEBR), a non-invasive 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 eye-blink activity. To test this, we recorded baseline sEBR and Inter Eye-Blink 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 eye-blink 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 (MBSR) 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 eye blink 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. PMID:26871460

Emotion modulation of the startle reflex in essential tremor: Blunted reactivity to unpleasant and pleasant pictures.

PubMed

Lafo, Jacob A; Mikos, Ania; Mangal, Paul C; Scott, Bonnie M; Trifilio, Erin; Okun, Michael S; Bowers, Dawn

2017-01-01

Essential tremor is a highly prevalent movement disorder characterized by kinetic tremor and mild cognitive-executive changes. These features are commonly attributed to abnormal cerebellar changes, resulting in disruption of cerebellar-thalamo-cortical networks. Less attention has been paid to alterations in basic emotion processing in essential tremor, despite known cerebellar-limbic interconnectivity. In the current study, we tested the hypothesis that a psychophysiologic index of emotional reactivity, the emotion modulated startle reflex, would be muted in individuals with essential tremor relative to controls. Participants included 19 essential tremor patients and 18 controls, who viewed standard sets of unpleasant, pleasant, and neutral pictures for six seconds each. During picture viewing, white noise bursts were binaurally presented to elicit startle eyeblinks measured over the orbicularis oculi. Consistent with past literature, controls' startle eyeblink responses were modulated according to picture valence (unpleasant > neutral > pleasant). In essential tremor participants, startle eyeblinks were not modulated by emotion. This modulation failure was not due to medication effects, nor was it due to abnormal appraisal of emotional picture content. Neuroanatomically, it remains unclear whether diminished startle modulation in essential tremor is secondary to aberrant cerebellar input to the amygdala, which is involved in priming the startle response in emotional contexts, or due to more direct disruption between the cerebellum and brainstem startle circuitry. If the former is correct, these findings may be the first to reveal dysregulation of emotional networks in essential tremor. Copyright © 2016 Elsevier Ltd. All rights reserved.

Startle habituation, sensory, and sensorimotor gating in trauma-affected refugees with posttraumatic stress disorder.

PubMed

Meteran, Hanieh; Vindbjerg, Erik; Uldall, Sigurd Wiingaard; Glenthøj, Birte; Carlsson, Jessica; Oranje, Bob

2018-05-17

Impairments in mechanisms underlying early information processing have been reported in posttraumatic stress disorder (PTSD); however, findings in the existing literature are inconsistent. This current study capitalizes on technological advancements of research on electroencephalographic event-related potential and applies it to a novel PTSD population consisting of trauma-affected refugees. A total of 25 trauma-affected refugees with PTSD and 20 healthy refugee controls matched on age, gender, and country of origin completed the study. In two distinct auditory paradigms sensory gating, indexed as P50 suppression, and sensorimotor gating, indexed as prepulse inhibition (PPI), startle reactivity, and habituation of the eye-blink startle response were examined. Within the P50 paradigm, N100 and P200 amplitudes were also assessed. In addition, correlations between psychophysiological and clinical measures were investigated. PTSD patients demonstrated significantly elevated stimuli responses across the two paradigms, reflected in both increased amplitude of the eye-blink startle response, and increased N100 and P200 amplitudes relative to healthy refugee controls. We found a trend toward reduced habituation in the patients, while the groups did not differ in PPI and P50 suppression. Among correlations, we found that eye-blink startle responses were associated with higher overall illness severity and lower levels of functioning. Fundamental gating mechanisms appeared intact, while the pattern of deficits in trauma-affected refugees with PTSD point toward a different form of sensory overload, an overall neural hypersensitivity and disrupted the ability to down-regulate stimuli responses. This study represents an initial step toward elucidating sensory processing deficits in a PTSD subgroup.

Threatening social context facilitates pain-related fear learning.

PubMed

Karos, Kai; Meulders, Ann; Vlaeyen, Johan W S

2015-03-01

This study investigated the effects of a threatening and a safe social context on learning pain-related fear, a key factor in the development and maintenance of chronic pain. We measured self-reported pain intensity, pain expectancy, pain-related fear (verbal ratings and eyeblink startle responses), and behavioral measures of avoidance (movement-onset latency and duration) using an established differential voluntary movement fear conditioning paradigm. Participants (N = 42) performed different movements with a joystick: during fear acquisition, movement in one direction (CS+) was followed by a painful stimulus (pain-US) whereas movement in another direction (CS-) was not. For participants in the threat group, an angry face was continuously presented in the background during the task, whereas in the safe group, a happy face was presented. During the extinction phase the pain-US was omitted. As compared to the safe social context, a threatening social context led to increased contextual fear and facilitated differentiation between CS+ and CS- movements regarding self-reported pain expectancy, fear of pain, eyeblink startle responses, and movement-onset latency. In contrast, self-reported pain intensity was not affected by social context. These data support the modulation of pain-related fear by social context. A threatening social context leads to stronger acquisition of (pain-related) fear and simultaneous contextual fear but does not affect pain intensity ratings. This knowledge may aid in the prevention of chronic pain and anxiety disorders and shows that social context might modulate pain-related fear without immediately affecting pain intensity itself. Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.

The stressed female brain: neuronal activity in the prelimbic but not infralimbic region of the medial prefrontal cortex suppresses learning after acute stress.

PubMed

Maeng, Lisa Y; Shors, Tracey J

2013-01-01

Women are nearly twice as likely as men to suffer from anxiety and post-traumatic stress disorder (PTSD), indicating that many females are especially vulnerable to stressful life experience. A profound sex difference in the response to stress is also observed in laboratory animals. Acute exposure to an uncontrollable stressful event disrupts associative learning during classical eyeblink conditioning in female rats but enhances this same type of learning process in males. These sex differences in response to stress are dependent on neuronal activity in similar but also different brain regions. Neuronal activity in the basolateral nucleus of the amygdala (BLA) is necessary in both males and females. However, neuronal activity in the medial prefrontal cortex (mPFC) during the stressor is necessary to modify learning in females but not in males. The mPFC is often divided into its prelimbic (PL) and infralimbic (IL) subregions, which differ both in structure and function. Through its connections to the BLA, we hypothesized that neuronal activity within the PL, but not IL, during the stressor is necessary to suppress learning in females. To test this hypothesis, either the PL or IL of adult female rats was bilaterally inactivated with GABAA agonist muscimol during acute inescapable swim stress. About 24 h later, all subjects were trained with classical eyeblink conditioning. Though stressed, females without neuronal activity in the PL learned well. In contrast, females with IL inactivation during the stressor did not learn well, behaving similarly to stressed vehicle-treated females. These data suggest that exposure to a stressful event critically engages the PL, but not IL, to disrupt associative learning in females. Together with previous studies, these data indicate that the PL communicates with the BLA to suppress learning after a stressful experience in females. This circuit may be similarly engaged in women who become cognitively impaired after stressful life events.

Evaluation of the effects of East Indian sandalwood oil and alpha-santalol on humans after transdermal absorption.

PubMed

Hongratanaworakit, T; Heuberger, E; Buchbauer, G

2004-01-01

The aim of the study was to investigate the effects of East Indian sandalwood oil ( Santalum album, Santalaceae) and alpha-santalol on physiological parameters as well as on mental and emotional conditions in healthy human subjects after transdermal absorption. In order to exclude any olfactory stimulation, the inhalation of the fragrances was prevented by breathing masks. Eight physiological parameters, i. e., blood oxygen saturation, blood pressure, breathing rate, eye-blink rate, pulse rate, skin conductance, skin temperature, and surface electromyogram were recorded. Subjective mental and emotional condition was assessed by means of rating scales. While alpha-santalol caused significant physiological changes which are interpreted in terms of a relaxing/sedative effect, sandalwood oil provoked physiological deactivation but behavioral activation. These findings are likely to represent an uncoupling of physiological and behavioral arousal processes by sandalwood oil.

The Coding Question.

PubMed

Gallistel, C R

2017-07-01

Recent electrophysiological results imply that the duration of the stimulus onset asynchrony in eyeblink conditioning is encoded by a mechanism intrinsic to the cerebellar Purkinje cell. This raises the general question - how is quantitative information (durations, distances, rates, probabilities, amounts, etc.) transmitted by spike trains and encoded into engrams? The usual assumption is that information is transmitted by firing rates. However, rate codes are energetically inefficient and computationally awkward. A combinatorial code is more plausible. If the engram consists of altered synaptic conductances (the usual assumption), then we must ask how numbers may be written to synapses. It is much easier to formulate a coding hypothesis if the engram is realized by a cell-intrinsic molecular mechanism. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed

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 (c) 2016 APA, all rights reserved).

Spontaneous Eye-Blink Rate as an Index of Reward Responsivity: Validation and Links to Bipolar Disorder

PubMed Central

Peckham, Andrew D.; Johnson, Sheri L.

2015-01-01

Extensive research supports the role of striatal dopamine in pursuing and responding to reward, and that eye-blink rate is a valid indicator of striatal dopamine. This study tested whether phasic changes in blink rate could provide an index of reward pursuit. This hypothesis was tested in people with bipolar I disorder (BD; a population with aberrations in reward responsivity), and in those without BD. Thirty-one adults with BD and 28 control participants completed a laboratory task involving effort towards monetary reward. Blink rate was recorded using eye-tracking at baseline, reward anticipation, and post-reward. Those in the BD group completed self-report measures relating to reward and ambition. Results showed that across all participants, blink rates increased from reward anticipation to post-reward. In the BD group, reward-relevant measures were strongly correlated with variation in blink rate. These findings provide validation for phasic changes in blink rate as an index of reward response. PMID:27274949

Multi-channel orbicularis oculi stimulation to restore eye-blink function in facial paralysis.

PubMed

Somia, N N; Zonnevijlle, E D; Stremel, R W; Maldonado, C; Gossman, M D; Barker, J H

2001-01-01

Facial paralysis due to facial nerve injury results in the loss of function of the muscles of the hemiface. The most serious complication in extreme cases is the loss of vision. In this study, we compared the effectiveness of single- and multiple-channel electrical stimulation to restore a complete and cosmetically acceptable eye blink. We established bilateral orbicularis oculi muscle (OOM) paralysis in eight dogs; the OOM of one side was directly stimulated using single-channel electrical stimulation and the opposite side was stimulated using multi-channel electrical stimulation. The changes in the palpebral fissure and complete palpebral closure were measured. The difference in current intensities between the multi-channel and single-channel simulation groups was significant, while only multi-channel stimulation produced complete eyelid closure. The latest electronic stimulation circuitry with high-quality implantable electrodes will make it possible to regulate precisely OOM contractions and thus generate complete and cosmetically acceptable eye-blink motion in patients with facial paralysis. Copyright 2001 Wiley-Liss, Inc.

Low dimensional temporal organization of spontaneous eye blinks in adults with developmental disabilities and stereotyped movement disorder.

PubMed

Lee, Mei-Hua; Bodfish, James W; Lewis, Mark H; Newell, Karl M

2010-01-01

This study investigated the mean rate and time-dependent sequential organization of spontaneous eye blinks in adults with intellectual and developmental disability (IDD) and individuals from this group who were additionally categorized with stereotypic movement disorder (IDD+SMD). The mean blink rate was lower in the IDD+SMD group than the IDD group and both of these groups had a lower blink rate than a contrast group of healthy adults. In the IDD group the n to n+1 sequential organization over time of the eye-blink durations showed a stronger compensatory organization than the contrast group suggesting decreased complexity/dimensionality of eye-blink behavior. Very low blink rate (and thus insufficient time series data) precluded analysis of time-dependent sequential properties in the IDD+SMD group. These findings support the hypothesis that both IDD and SMD are associated with a reduction in the dimension and adaptability of movement behavior and that this may serve as a risk factor for the expression of abnormal movements.

Effects of transient blur and VDT screen luminance changes on eyeblink rate.

PubMed

Cardona, Genís; Gómez, Marcelo; Quevedo, Lluïsa; Gispets, Joan

2014-10-01

A study was designed to evaluate the efficacy of three different strategies aiming at increasing spontaneous eyeblink rate (SEBR) during computer use. A total of 12 subjects (5 female) with a mean age of 28.7 years were instructed to read a text presented on a computer display terminal during 15min. Four reading sessions (reference and three "blinking events" [BE]) were programmed in which SEBR was digitally recorded. "Blinking events" were based on either a slight distortion of the text characters or on the presentation of a white screen instead of the text, with or without accompanying blinking instructions. All BE had a duration of 20ms and occurred every 15s. Participants graded the intrusiveness of each BE configuration, and the number of lines participants read in each session was recorded. Data from 11 subjects was analysed. A statistically significant difference in SEBR was encountered between the experimental configuration consisting on a white screen plus blinking instructions (7.8 blinks/min) and both reference (5.2 blinks/min; p=0.049) and white screen without blinking instructions (4.8 blinks/min; p=0.038). All three BE had superior levels of intrusiveness than reference conditions, although the performance of participants (line count) was not compromised. The joint contribution of white screen and blinking instructions has been shown to result in a short term improvement in blinking rate in the present sample of non-dry eye computer users. Further work is necessary to improve the acceptance of any BE aiming at influencing SEBR. Copyright © 2014 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

What Does Eye-Blink Rate Variability Dynamics Tell Us About Cognitive Performance?

PubMed Central

Paprocki, Rafal; Lenskiy, Artem

2017-01-01

Cognitive performance is defined as the ability to utilize knowledge, attention, memory, and working memory. In this study, we briefly discuss various markers that have been proposed to predict cognitive performance. Next, we develop a novel approach to characterize cognitive performance by analyzing eye-blink rate variability dynamics. Our findings are based on a sample of 24 subjects. The subjects were given a 5-min resting period prior to a 10-min IQ test. During both stages, eye blinks were recorded from Fp1 and Fp2 electrodes. We found that scale exponents estimated for blink rate variability during rest were correlated with subjects' performance on the subsequent IQ test. This surprising phenomenon could be explained by the person to person variation in concentrations of dopamine in PFC and accumulation of GABA in the visual cortex, as both neurotransmitters play a key role in cognitive processes and affect blinking. This study demonstrates the possibility that blink rate variability dynamics at rest carry information about cognitive performance and can be employed in the assessment of cognitive abilities without taking a test. PMID:29311876

Interoceptive threat leads to defensive mobilization in highly anxiety sensitive persons.

PubMed

Melzig, Christiane A; Holtz, Katharina; Michalowski, Jaroslaw M; Hamm, Alfons O

2011-06-01

To study defensive mobilization elicited by the exposure to interoceptive arousal sensations, we exposed highly anxiety sensitive students to a symptom provocation task. Symptom reports, autonomic arousal, and the startle eyeblink response were monitored during guided hyperventilation and a recovery period in 26 highly anxiety sensitive persons and 22 controls. Normoventilation was used as a non-provocative comparison condition. Hyperventilation led to autonomic arousal and a marked increase in somatic symptoms. While high and low anxiety sensitive persons did not differ in their defensive activation during hyperventilation, group differences were detected during early recovery. Highly anxiety sensitive students exhibited a potentiation of startle response magnitudes and increased autonomic arousal after hyper- as compared to after normoventilation, indicating defensive mobilization evoked by the prolonged presence of feared somatic sensations. Copyright © 2010 Society for Psychophysiological Research.

Variable Foreperiod Deficits in Parkinson's Disease: Dissociation across Reflexive and Voluntary Behaviors

ERIC Educational Resources Information Center

Jurkowski, A.J.; Stepp, E.; Hackley, S.A.

2005-01-01

The effect of a visual warning signal (1.0-6.5s random foreperiod, FP) on the latency of voluntary (hand-grip) and reflexive (startle-eyeblink) reactions was investigated in Parkinson's disease (PD) patients and in young and aged control subjects. Equivalent FP effects on blink were observed across groups. By contrast, FP effects diverged for…

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

PubMed

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.

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

PubMed Central

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

Motivational priming and processing interrupt: startle reflex modulation during shallow and deep processing of emotional words.

PubMed

Herbert, Cornelia; Kissler, Johanna

2010-05-01

Valence-driven modulation of the startle reflex, that is larger eyeblinks during viewing of unpleasant pictures and inhibited blinks while viewing pleasant pictures, is well documented. The current study investigated, whether this motivational priming pattern also occurs during processing of unpleasant and pleasant words, and to what extent it is influenced by shallow vs. deep encoding of verbal stimuli. Emotional and neutral adjectives were presented for 5s, and the acoustically elicited startle eyeblink response was measured while subjects memorized the words by means of shallow or deep processing strategies. Results showed blink potentiation to unpleasant and blink inhibition to pleasant adjectives in subjects using shallow encoding strategies. In subjects using deep-encoding strategies, blinks were larger for pleasant than unpleasant or neutral adjectives. In line with this, free recall of pleasant words was also better in subjects who engaged in deep processing. The results suggest that motivational priming holds as long as processing is perceptual. However, during deep processing the startle reflex appears to represent a measure of "processing interrupt", facilitating blinks to those stimuli that are more deeply encoded. Copyright 2010 Elsevier B.V. All rights reserved.

Developing Physiologic Models for Emergency Medical Procedures Under Microgravity

NASA Technical Reports Server (NTRS)

Parker, Nigel; O'Quinn, Veronica

2012-01-01

Several technological enhancements have been made to METI's commercial Emergency Care Simulator (ECS) with regard to how microgravity affects human physiology. The ECS uses both a software-only lung simulation, and an integrated mannequin lung that uses a physical lung bag for creating chest excursions, and a digital simulation of lung mechanics and gas exchange. METI s patient simulators incorporate models of human physiology that simulate lung and chest wall mechanics, as well as pulmonary gas exchange. Microgravity affects how O2 and CO2 are exchanged in the lungs. Procedures were also developed to take into affect the Glasgow Coma Scale for determining levels of consciousness by varying the ECS eye-blinking function to partially indicate the level of consciousness of the patient. In addition, the ECS was modified to provide various levels of pulses from weak and thready to hyper-dynamic to assist in assessing patient conditions from the femoral, carotid, brachial, and pedal pulse locations.

Developing Physiologic Models for Emergency Medical Procedures Under Microgravity

NASA Technical Reports Server (NTRS)

Parker, Nigel; OQuinn, Veronica

2012-01-01

Several technological enhancements have been made to METI's commercial Emergency Care Simulator (ECS) with regard to how microgravity affects human physiology. The ECS uses both a software-only lung simulation, and an integrated mannequin lung that uses a physical lung bag for creating chest excursions, and a digital simulation of lung mechanics and gas exchange. METI's patient simulators incorporate models of human physiology that simulate lung and chest wall mechanics, as well as pulmonary gas exchange. Microgravity affects how O2 and CO2 are exchanged in the lungs. Procedures were also developed to take into affect the Glasgow Coma Scale for determining levels of consciousness by varying the ECS eye-blinking function to partially indicate the level of consciousness of the patient. In addition, the ECS was modified to provide various levels of pulses from weak and thready to hyper-dynamic to assist in assessing patient conditions from the femoral, carotid, brachial, and pedal pulse locations.

Histone deacetylase inhibitors improve learning consolidation in young and in KA-induced-neurodegeneration and SAMP-8-mutant mice.

PubMed

Fontán-Lozano, Angela; Romero-Granados, Rocío; Troncoso, Julieta; Múnera, Alejandro; Delgado-García, José María; Carrión, Angel M

2008-10-01

Histone deacetylases (HDAC) are enzymes that maintain chromatin in a condensate state, related with absence of transcription. We have studied the role of HDAC on learning and memory processes. Both eyeblink classical conditioning (EBCC) and object recognition memory (ORM) induced an increase in histone H3 acetylation (Ac-H3). Systemic treatment with HDAC inhibitors improved cognitive processes in EBCC and in ORM tests. Immunohistochemistry and gene expression analyses indicated that administration of HDAC inhibitors decreased the stimulation threshold for Ac-H3, and gene expression to reach the levels required for learning and memory. Finally, we evaluated the effect of systemic administration of HDAC inhibitors to mice models of neurodegeneration and aging. HDAC inhibitors reversed learning and consolidation deficits in ORM in these models. These results point out HDAC inhibitors as candidate agents for the palliative treatment of learning and memory impairments in aging and in neurodegenerative disorders.

Impaired eye blink classical conditioning distinguishes dystonic patients with and without tremor.

PubMed

Antelmi, E; Di Stasio, F; Rocchi, L; Erro, R; Liguori, R; Ganos, C; Brugger, F; Teo, J; Berardelli, A; Rothwell, J; Bhatia, K P

2016-10-01

Tremor is frequently associated with dystonia, but its pathophysiology is still unclear. Dysfunctions of cerebellar circuits are known to play a role in the pathophysiology of action-induced tremors, and cerebellar impairment has frequently been associated to dystonia. However, a link between dystonic tremor and cerebellar abnormalities has not been demonstrated so far. Twenty-five patients with idiopathic isolated cervical dystonia, with and without tremor, were enrolled. We studied the excitability of inhibitory circuits in the brainstem by measuring the R2 blink reflex recovery cycle (BRC) and implicit learning mediated by the cerebellum by means of eyeblink classical conditioning (EBCC). Results were compared with those obtained in a group of age-matched healthy subjects (HS). Statistical analysis did not disclose any significant clinical differences among dystonic patients with and without tremor. Patients with dystonia (regardless of the presence of tremor) showed decreased inhibition of R2 blink reflex by conditioning pulses compared with HS. Patients with dystonic tremor showed a decreased number of conditioned responses in the EBCC paradigm compared to HS and dystonic patients without tremor. The present data show that cerebellar impairment segregates with the presence of tremor in patients with dystonia, suggesting that the cerebellum might have a role in the occurrence of dystonic tremor. Copyright © 2016 Elsevier Ltd. All rights reserved.

Classic conditioning in aged rabbits: delay, trace, and long-delay conditioning.

PubMed

Solomon, P R; Groccia-Ellison, M E

1996-06-01

Young (0.5 years) and aged (2+, 3+, and 4+ years) rabbits underwent acquisition of the classically conditioned nictitating membrane response in a delay (500-ms conditioned stimulus [CS], 400-ms interstimulus interval [ISI]), long-delay (1,000-ms CS, 900-ms ISI), or trace (500-ms CS, 400-ms stimulus-free period) paradigm. Collapsing across age groups, there is a general tendency for animals to acquire trace conditioning more slowly than delay conditioning. Collapsing across conditioning paradigms, there is a general tendency for aged animals to acquire more slowly than younger animals. Of greater significance, however, are the age differences in the different conditioning paradigms. In the delay and long-delay paradigms, significant conditioning deficits first appeared in the 4(+)-year-old group. In the trace conditioning paradigm, significant conditioning deficits became apparent in the 2(+)-year-old animals.

An agonist–antagonist cerebellar nuclear system controlling eyelid kinematics during motor learning

PubMed Central

Sánchez-Campusano, Raudel; Gruart, Agnès; Fernández-Mas, Rodrigo; Delgado-García, José M.

2012-01-01

The presence of two antagonistic groups of deep cerebellar nuclei neurons has been reported as necessary for a proper dynamic control of learned motor responses. Most models of cerebellar function seem to ignore the biomechanical need for a double activation–deactivation system controlling eyelid kinematics, since most of them accept that, for closing the eyelid, only the activation of the orbicularis oculi (OO) muscle (via the red nucleus to the facial motor nucleus) is necessary, without a simultaneous deactivation of levator palpebrae motoneurons (via unknown pathways projecting to the perioculomotor area). We have analyzed the kinetic neural commands of two antagonistic types of cerebellar posterior interpositus neuron (IPn) (types A and B), the electromyographic (EMG) activity of the OO muscle, and eyelid kinematic variables in alert behaving cats during classical eyeblink conditioning, using a delay paradigm. We addressed the hypothesis that the interpositus nucleus can be considered an agonist–antagonist system controlling eyelid kinematics during motor learning. To carry out a comparative study of the kinetic–kinematic relationships, we applied timing and dispersion pattern analyses. We concluded that, in accordance with a dominant role of cerebellar circuits for the facilitation of flexor responses, type A neurons fire during active eyelid downward displacements—i.e., during the active contraction of the OO muscle. In contrast, type B neurons present a high tonic rate when the eyelids are wide open, and stop firing during any active downward displacement of the upper eyelid. From a functional point of view, it could be suggested that type B neurons play a facilitative role for the antagonistic action of the levator palpebrae muscle. From an anatomical point of view, the possibility that cerebellar nuclear type B neurons project to the perioculomotor area—i.e., more or less directly onto levator palpebrae motoneurons—is highly appealing. PMID:22435053

A quantitative analysis of sensitivity to the conditioned reinforcing value of terminal-link stimuli in a concurrent-chains schedule.

PubMed Central

Omino, T

1993-01-01

Pigeons were exposed to a concurrent-chains schedule in which a single variable-interval 30-s schedule was used in the initial links and fixed-time schedules were used in the terminal links. Three types of keylight conditions were used in the terminal links. In the first condition, different delays were associated with different keylight stimuli (cued condition). In the second condition, different delays were associated with the same stimulus, either a blackout (uncued blackout condition) or a white key (uncued white condition). Paired values of terminal-link fixed-time schedules differed by a constant ratio of 3:1, while the absolute value of delays was varied from 3 s to 54 s. The results showed that choice proportions for the shorter of two delays increased when the absolute size of the delays was increased for all keylight conditions. Further, the choice proportions for the shorter delay increased from the uncued blackout condition, to the uncued white condition, to the cued condition. A modified version of Fantino's (1969) delay-reduction model (expressed as a function relating the response ratio to the delay-reduction ratio) can be applied to these data by showing that sensitivity to delay reduction increased from the uncued blackout condition, to the uncued white condition, to the cued condition. Thus, the present study demonstrated that a modified version of the delay-reduction model can be used to assess quantitative differences in the terminal-link keylight condition in terms of sensitivity to delay reduction (i.e., the conditioned reinforcing value of the terminal-link keylight stimuli). PMID:8283150

Impact of aerobic exercise intensity on craving and reactivity to smoking cues.

PubMed

Janse Van Rensburg, Kate; Elibero, Andrea; Kilpatrick, Marcus; Drobes, David J

2013-06-01

Aerobic exercise can acutely reduce cigarette cravings during periods of nicotine deprivation. The primary aim of this study was to assess the differential effects of light and vigorous intensity aerobic exercise on cigarette cravings, subjective and physiological reactivity to smoking cues, and affect after overnight nicotine deprivation. A secondary aim was to examine cortisol change as a mediator of the effects of exercise on smoking motivation. 162 (55 female, 107 male) overnight nicotine-deprived smokers were randomized to one of three exercise conditions: light intensity, vigorous intensity, or a passive control condition. After each condition, participants engaged in a standardized cue reactivity assessment. Self-reported urges to smoke, affect, and salivary cortisol were assessed at baseline (i.e., before each condition), immediately after each condition, and after the cue reactivity assessment. Light and vigorous exercise significantly decreased urges to smoke and increased positive affect, relative to the control condition. In addition, those in the vigorous exercise condition demonstrated suppressed appetitive reactivity to smoking cues, as indexed by the startle eyeblink reflex. Although exercise intensity was associated with expected changes in cortisol concentration, these effects were not related to changes in craving or cue reactivity. Both light and vigorous exercise can reduce general cravings to smoke, whereas vigorous exercise appears especially well-suited for reducing appetitive reactions to cues that may precede smoking. Results did not support exercise-induced cortisol release as a mechanism for these effects. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Hybrid EEG-fNIRS-Based Eight-Command Decoding for BCI: Application to Quadcopter Control.

PubMed

Khan, Muhammad Jawad; Hong, Keum-Shik

2017-01-01

In this paper, a hybrid electroencephalography-functional near-infrared spectroscopy (EEG-fNIRS) scheme to decode eight active brain commands from the frontal brain region for brain-computer interface is presented. A total of eight commands are decoded by fNIRS, as positioned on the prefrontal cortex, and by EEG, around the frontal, parietal, and visual cortices. Mental arithmetic, mental counting, mental rotation, and word formation tasks are decoded with fNIRS, in which the selected features for classification and command generation are the peak, minimum, and mean ΔHbO values within a 2-s moving window. In the case of EEG, two eyeblinks, three eyeblinks, and eye movement in the up/down and left/right directions are used for four-command generation. The features in this case are the number of peaks and the mean of the EEG signal during 1 s window. We tested the generated commands on a quadcopter in an open space. An average accuracy of 75.6% was achieved with fNIRS for four-command decoding and 86% with EEG for another four-command decoding. The testing results show the possibility of controlling a quadcopter online and in real-time using eight commands from the prefrontal and frontal cortices via the proposed hybrid EEG-fNIRS interface.

Psychophysiological response patterns and risky sexual behavior in heterosexual and homosexual men.

PubMed

Janssen, Erick; Goodrich, David; Petrocelli, John V; Bancroft, John

2009-08-01

The past few years have seen an increased awareness of the relevance of studying the role of sexual response, emotion, and traits such as sensation seeking and the propensity for sexual inhibition in risky sexual behavior. The current study examined the association between self-reported sexual risk taking and psychophysiological response patterns in 76 heterosexual and homosexual men. Measures included genital, electrodermal, startle eyeblink, and cardiovascular responses, and stimuli included threatening (depicting coercive sexual interactions) and nonthreatening (depicting consensual sexual interactions) sexual film excerpts. Sexual risk taking was hypothesized to be associated with decreased inhibition of sexual arousal and hyporeactive affective and autonomic responses to threatening sexual stimuli. Controlling for age and number of sexual partners in the past year, sexual risk taking (number of partners during the past 3 years with whom no condoms were used) was found to be associated with stronger genital responses and smaller eyeblink responses to both threatening and nonthreatening sexual stimuli. Correlations between genital and subjective sexual arousal were relatively low. Sexual risk taking was related to sensation seeking but not to the propensity for sexual inhibition. The findings suggest that risky sexual behavior may involve a role for psychophysiological mechanisms that are specific to sex as well as for ones that are associated with more general approach/avoidance response tendencies.

Identification of a functionally distinct truncated BDNF mRNA splice variant and protein in Trachemys scripta elegans.

PubMed

Ambigapathy, Ganesh; Zheng, Zhaoqing; Li, Wei; Keifer, Joyce

2013-01-01

Brain-derived neurotrophic factor (BDNF) has a diverse functional role and complex pattern of gene expression. Alternative splicing of mRNA transcripts leads to further diversity of mRNAs and protein isoforms. Here, we describe the regulation of BDNF mRNA transcripts in an in vitro model of eyeblink classical conditioning and a unique transcript that forms a functionally distinct truncated BDNF protein isoform. Nine different mRNA transcripts from the BDNF gene of the pond turtle Trachemys scripta elegans (tBDNF) are selectively regulated during classical conditioning: exon I mRNA transcripts show no change, exon II transcripts are downregulated, while exon III transcripts are upregulated. One unique transcript that codes from exon II, tBDNF2a, contains a 40 base pair deletion in the protein coding exon that generates a truncated tBDNF protein. The truncated transcript and protein are expressed in the naïve untrained state and are fully repressed during conditioning when full-length mature tBDNF is expressed, thereby having an alternate pattern of expression in conditioning. Truncated BDNF is not restricted to turtles as a truncated mRNA splice variant has been described for the human BDNF gene. Further studies are required to determine the ubiquity of truncated BDNF alternative splice variants across species and the mechanisms of regulation and function of this newly recognized BDNF protein.

Identification of a Functionally Distinct Truncated BDNF mRNA Splice Variant and Protein in Trachemys scripta elegans

PubMed Central

Ambigapathy, Ganesh; Zheng, Zhaoqing; Li, Wei; Keifer, Joyce

2013-01-01

Brain-derived neurotrophic factor (BDNF) has a diverse functional role and complex pattern of gene expression. Alternative splicing of mRNA transcripts leads to further diversity of mRNAs and protein isoforms. Here, we describe the regulation of BDNF mRNA transcripts in an in vitro model of eyeblink classical conditioning and a unique transcript that forms a functionally distinct truncated BDNF protein isoform. Nine different mRNA transcripts from the BDNF gene of the pond turtle Trachemys scripta elegans (tBDNF) are selectively regulated during classical conditioning: exon I mRNA transcripts show no change, exon II transcripts are downregulated, while exon III transcripts are upregulated. One unique transcript that codes from exon II, tBDNF2a, contains a 40 base pair deletion in the protein coding exon that generates a truncated tBDNF protein. The truncated transcript and protein are expressed in the naïve untrained state and are fully repressed during conditioning when full-length mature tBDNF is expressed, thereby having an alternate pattern of expression in conditioning. Truncated BDNF is not restricted to turtles as a truncated mRNA splice variant has been described for the human BDNF gene. Further studies are required to determine the ubiquity of truncated BDNF alternative splice variants across species and the mechanisms of regulation and function of this newly recognized BDNF protein. PMID:23825634

The Separate and Cumulative Effects of TBI and PTSD on Cognitive Function and Emotional Control

DTIC Science & Technology

2012-04-01

indicate an altered profile of persistent hyper- arousal , exaggerated startle responses (Fani et al., 2012; Pole, 2007), larger eye-blink, eye pupil...were each compared. This separation kept variables such as word frequency, valence, arousal , and other properties as consistent as possible across...number of syllables and frequency. Only high arousal Negative and Positive words were used and arousal and valence ratings for Neutral, Negative and

Signal functions in delayed reinforcement

PubMed Central

Lattal, Kennon A.

1984-01-01

Three experiments were conducted with pigeons to examine the role of the signal in delay-of-reinforcement procedures. In the first, a blackout accompanying a period of nonreinforcement increased key-peck response rates maintained by immediate reinforcement. The effects of dissociating the blackout from the delay interval were examined in the second experiment. In three conditions, blackouts and unsignaled delays were negatively correlated or occurred randomly with respect to one another. A signaled delay and an unsignaled delay that omitted the blackouts were studied in two other conditions. All delay-of-reinforcement conditions generally produced response rates lower than those produced by immediate reinforcement. Signaled delays maintained higher response rates than did any of the various unsignaled-delay conditions, with or without dissociated blackouts. The effects of these latter conditions did not differ systematically from one another. The final experiment showed that response rates varied as a function of the frequency with which a blackout accompanied delay intervals. By eliminating a number of methodological difficulties present in previous delay-of-reinforcement experiments, these results suggest the importance of the signal in maintaining responding during delay-of-reinforcement procedures and, conversely, the importance of the delay interval in decreasing responding. PMID:16812387

Conditioned social dominance threat: observation of others' social dominance biases threat learning.

PubMed

Haaker, Jan; Molapour, Tanaz; Olsson, Andreas

2016-10-01

Social groups are organized along dominance hierarchies, which determine how we respond to threats posed by dominant and subordinate others. The persuasive impact of these dominance threats on mental and physical well-being has been well described but it is unknown how dominance rank of others bias our experience and learning in the first place. We introduce a model of conditioned social dominance threat in humans, where the presence of a dominant other is paired with an aversive event. Participants first learned about the dominance rank of others by observing their dyadic confrontations. During subsequent fear learning, the dominant and subordinate others were equally predictive of an aversive consequence (mild electric shock) to the participant. In three separate experiments, we show that participants' eye-blink startle responses and amygdala reactivity adaptively tracked dominance of others during observation of confrontation. Importantly, during fear learning dominant vs subordinate others elicited stronger and more persistent learned threat responses as measured by physiological arousal and amygdala activity. Our results characterize the neural basis of learning through observing conflicts between others, and how this affects subsequent learning through direct, personal experiences. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Conditioned social dominance threat: observation of others’ social dominance biases threat learning

PubMed Central

Molapour, Tanaz; Olsson, Andreas

2016-01-01

Social groups are organized along dominance hierarchies, which determine how we respond to threats posed by dominant and subordinate others. The persuasive impact of these dominance threats on mental and physical well-being has been well described but it is unknown how dominance rank of others bias our experience and learning in the first place. We introduce a model of conditioned social dominance threat in humans, where the presence of a dominant other is paired with an aversive event. Participants first learned about the dominance rank of others by observing their dyadic confrontations. During subsequent fear learning, the dominant and subordinate others were equally predictive of an aversive consequence (mild electric shock) to the participant. In three separate experiments, we show that participants’ eye-blink startle responses and amygdala reactivity adaptively tracked dominance of others during observation of confrontation. Importantly, during fear learning dominant vs subordinate others elicited stronger and more persistent learned threat responses as measured by physiological arousal and amygdala activity. Our results characterize the neural basis of learning through observing conflicts between others, and how this affects subsequent learning through direct, personal experiences. PMID:27217107

Additive Effects of Threat-of-Shock and Picture Valence on Startle Reflex Modulation

PubMed Central

Bublatzky, Florian; Guerra, Pedro M.; Pastor, M. Carmen; Schupp, Harald T.; Vila, Jaime

2013-01-01

The present study examined the effects of sustained anticipatory anxiety on the affective modulation of the eyeblink startle reflex. Towards this end, pleasant, neutral and unpleasant pictures were presented as a continuous stream during alternating threat-of-shock and safety periods, which were cued by colored picture frames. Orbicularis-EMG to auditory startle probes and electrodermal activity were recorded. Previous findings regarding affective picture valence and threat-of-shock modulation were replicated. Of main interest, anticipating aversive events and viewing affective pictures additively modulated defensive activation. Specifically, despite overall potentiated startle blink magnitude in threat-of-shock conditions, the startle reflex remained sensitive to hedonic picture valence. Finally, skin conductance level revealed sustained sympathetic activation throughout the entire experiment during threat- compared to safety-periods. Overall, defensive activation by physical threat appears to operate independently from reflex modulation by picture media. The present data confirms the importance of simultaneously manipulating phasic-fear and sustained-anxiety in studying both normal and abnormal anxiety. PMID:23342060

Synthetic tactile perception induced by transcranial alternating-current stimulation can substitute for natural sensory stimulus in behaving rabbits.

PubMed

Márquez-Ruiz, Javier; Ammann, Claudia; Leal-Campanario, Rocío; Ruffini, Giulio; Gruart, Agnès; Delgado-García, José M

2016-01-21

The use of brain-derived signals for controlling external devices has long attracted the attention from neuroscientists and engineers during last decades. Although much effort has been dedicated to establishing effective brain-to-computer communication, computer-to-brain communication feedback for "closing the loop" is now becoming a major research theme. While intracortical microstimulation of the sensory cortex has already been successfully used for this purpose, its future application in humans partly relies on the use of non-invasive brain stimulation technologies. In the present study, we explore the potential use of transcranial alternating-current stimulation (tACS) for synthetic tactile perception in alert behaving animals. More specifically, we determined the effects of tACS on sensory local field potentials (LFPs) and motor output and tested its capability for inducing tactile perception using classical eyeblink conditioning in the behaving animal. We demonstrated that tACS of the primary somatosensory cortex vibrissa area could indeed substitute natural stimuli during training in the associative learning paradigm.

Stressful Experience and Learning Across the Lifespan

PubMed Central

Shors, Tracey J.

2012-01-01

It is usually assumed that stressful life events interfere with our ability to acquire new information. However, many studies suggest that stressful experience can enhance processes involved in learning. The types of learning that are enhanced after stressful experiences include classical fear and eyeblink conditioning, as well as processes related to learning about threatening stimuli. Stressful life experiences do seem to interfere with processes involved in memory, often expressed as deficits in the retention or retrieval of information that was acquired prior to and was unrelated to the stressful experience. The trends are limited, as are their implications, because most studies examine adult males, yet the effects of stress on learning processes are influenced by age and sex differences. With respect to mechanisms and anatomical substrates, the effects of stress on learning are usually dependent on the action of stress hormones in combination with neuronal activities within the hippocampus, amygdala, the bed nucleus of the stria terminalis, and the prefrontal cortex. PMID:16318589

Altitude acclimatization improves submaximal cognitive performance in mice and involves an imbalance of the cholinergic system.

PubMed

Guerra-Narbona, R; Delgado-García, J M; López-Ramos, J C

2013-06-15

The aim of this work was to reveal a hypothetical improvement of cognitive abilities in animals acclimatized to altitude and performing under ground level conditions, when looking at submaximal performance, once seen that it was not possible when looking at maximal scores. We modified contrasted cognitive tasks (object recognition, operant conditioning, eight-arm radial maze, and classical conditioning of the eyeblink reflex), increasing their complexity in an attempt to find performance differences in acclimatized animals vs. untrained controls. In addition, we studied, through immunohistochemical quantification, the expression of choline acetyltransferase and acetyl cholinesterase, enzymes involved in the synthesis and degradation of acetylcholine, in the septal area, piriform and visual cortexes, and the hippocampal CA1 area of animals submitted to acute hypobaric hypoxia, or acclimatized to this simulated altitude, to find a relationship between the cholinergic system and a cognitive improvement due to altitude acclimatization. Results showed subtle improvements of the cognitive capabilities of acclimatized animals in all of the tasks when performed under ground-level conditions (although not before 24 h), in the three tasks used to test explicit memory (object recognition, operant conditioning in the Skinner box, and eight-arm radial maze) and (from the first conditioning session) in the classical conditioning task used to evaluate implicit memory. An imbalance of choline acetyltransferase/acetyl cholinesterase expression was found in acclimatized animals, mainly 24 h after the acclimatization period. In conclusion, altitude acclimatization improves cognitive capabilities, in a process parallel to an imbalance of the cholinergic system.

Viewing loved faces inhibits defense reactions: a health-promotion mechanism?

PubMed

Guerra, Pedro; Sánchez-Adam, Alicia; Anllo-Vento, Lourdes; Ramírez, Isabel; Vila, Jaime

2012-01-01

We have known for decades that social support is associated with positive health outcomes. And yet, the neurophysiological mechanisms underlying this association remain poorly understood. The link between social support and positive health outcomes is likely to depend on the neurophysiological regulatory mechanisms underlying reward and defensive reactions. The present study examines the hypothesis that emotional social support (love) provides safety cues that activate the appetitive reward system and simultaneously inhibit defense reactions. Using the startle probe paradigm, 54 undergraduate students (24 men) viewed black and white photographs of loved (romantic partner, father, mother, and best friend), neutral (unknown), and unpleasant (mutilated) faces. Eye-blink startle, zygomatic major activity, heart rate, and skin conductance responses to the faces, together with subjective ratings of valence, arousal, and dominance, were obtained. Viewing loved faces induced a marked inhibition of the eye-blink startle response accompanied by a pattern of zygomatic, heart rate, skin conductance, and subjective changes indicative of an intense positive emotional response. Effects were similar for men and women, but the startle inhibition and the zygomatic response were larger in female participants. A comparison between the faces of the romantic partner and the parent who shares the partner's gender further suggests that this effect is not attributable to familiarity or arousal. We conclude that this inhibitory capacity may contribute to the health benefits associated with social support.

Inhibition of the amygdala central nucleus by stimulation of cerebellar output in rats: a putative mechanism for extinction of the conditioned fear response.

PubMed

Magal, Ari; Mintz, Matti

2014-11-01

The amygdala and the cerebellum serve two distinctively different functions. The amygdala plays a role in the expression of emotional information, whereas the cerebellum is involved in the timing of discrete motor responses. Interaction between these two systems is the basis of the two-stage theory of learning, according to which an encounter with a challenging event triggers fast classical conditioning of fear-conditioned responses in the amygdala and slow conditioning of motor-conditioned responses in the cerebellum. A third stage was hypothesised when an apparent interaction between amygdala and cerebellar associative plasticity was observed: an adaptive rate of cerebellum-dependent motor-conditioned responses was associated with a decrease in amygdala-dependent fear-conditioned responses, and was interpreted as extinction of amygdala-related fear-conditioned responses by the cerebellar output. To explore this hypothesis, we mimicked some components of classical eyeblink conditioning in anesthetised rats by applying an aversive periorbital pulse as an unconditioned stimulus and a train of pulses to the cerebellar output nuclei as a cerebellar neuronal-conditioned response. The central amygdala multiple unit response to the periorbital pulse was measured with or without a preceding train to the cerebellar output nuclei. The results showed that activation of the cerebellar output nuclei prior to periorbital stimulation produced diverse patterns of inhibition of the amygdala response to the periorbital aversive stimulus, depending upon the nucleus stimulated, the laterality of the nucleus stimulated, and the stimulus interval used. These results provide a putative extinction mechanism of learned fear behavior, and could have implications for the treatment of pathologies involving abnormal fear responses by using motor training as therapy. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

PARAMETRIC ANALYSIS OF DELAYED PRIMARY AND CONDITIONED REINFORCERS

PubMed Central

Leon, Yanerys; Borrero, John C.; DeLeon, Iser G.

2016-01-01

We examined the effects of delayed reinforcement on the responding of individuals with intellectual disabilities. Three conditions were evaluated: (a) food reinforcement, (b) token reinforcement with a postsession exchange opportunity, and (c) token reinforcement with a posttrial exchange opportunity. Within each condition, we assessed responding given (a) a no-reinforcement baseline, (b) immediate reinforcement, and (c) delayed reinforcement, in which responses produced a reinforcer after 1 of 6 delays. Results suggest that delayed food produced greater response persistence than did delayed tokens. PMID:27174440

Differential Acetylcholine Release in the Prefrontal Cortex and Hippocampus During Pavlovian Trace and Delay Conditioning

PubMed Central

Flesher, M. Melissa; Butt, Allen E.; Kinney-Hurd, Brandee L.

2011-01-01

Pavlovian trace conditioning critically depends on the medial prefrontal cortex (mPFC) and hippocampus (HPC), whereas delay conditioning does not depend on these brain structures. Given that the cholinergic basal forebrain system modulates activity in both the mPFC and HPC, it was reasoned that the level of acetylcholine (ACh) release in these regions would show distinct profiles during testing in trace and delay conditioning paradigms. To test this assumption, microdialysis probes were implanted unilaterally into the mPFC and HPC of rats that were pre-trained in appetitive trace and delay conditioning paradigms using different conditional stimuli in the two tasks. On the day of microdialysis testing, dialysate samples were collected during a quiet baseline interval before trials were initiated, and again during performance in separate blocks of trace and delay conditioning trials in each animal. ACh levels were quantified using high performance liquid chromatography and electrochemical detection techniques. Consistent with our hypothesis, results showed that ACh release in the mPFC was greater during trace conditioning than during delay conditioning. The level of ACh released during trace conditioning in the HPC was also greater than the levels observed during delay conditioning. While ACh efflux in both the mPFC and HPC selectively increased during trace conditioning, ACh levels in the mPFC during trace conditioning testing showed the greatest increases observed. These results demonstrate a dissociation in cholinergic activation of the mPFC and HPC during performance in trace but not delay appetitive conditioning, where this cholinergic activity may contribute to attentional mechanisms, adaptive response timing, or memory consolidation necessary for successful trace conditioning. PMID:21514394

Structural Properties and Estimation of Delay Systems. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Kwong, R. H. S.

1975-01-01

Two areas in the theory of delay systems were studied: structural properties and their applications to feedback control, and optimal linear and nonlinear estimation. The concepts of controllability, stabilizability, observability, and detectability were investigated. The property of pointwise degeneracy of linear time-invariant delay systems is considered. Necessary and sufficient conditions for three dimensional linear systems to be made pointwise degenerate by delay feedback were obtained, while sufficient conditions for this to be possible are given for higher dimensional linear systems. These results were applied to obtain solvability conditions for the minimum time output zeroing control problem by delay feedback. A representation theorem is given for conditional moment functionals of general nonlinear stochastic delay systems, and stochastic differential equations are derived for conditional moment functionals satisfying certain smoothness properties.

Robust hippocampal responsivity during retrieval of consolidated associative memory.

PubMed

Hattori, Shoai; Chen, Lillian; Weiss, Craig; Disterhoft, John F

2015-05-01

A contentious point in memory research is whether or not the hippocampus plays a time-limited role in the consolidation of declarative memories. A widely held view is that declarative memories are initially encoded in the hippocampus, then transferred to the neocortex for long-term storage. Alternate views argue instead that the hippocampus continues to play a role in remote memory recall. These competing theories are largely based on human amnesic and animal lesion/inactivation studies. However, in vivo electrophysiological evidence supporting these views is scarce. Given that other studies examining the role of the hippocampus in remote memory retrieval using lesion and imaging techniques in human and animal models have provided mixed results, it would be particularly useful to gain insight at the in vivo electrophysiological level. Here we report hippocampal single-neuron and theta activity recorded longitudinally during acquisition and remote retrieval of trace eyeblink conditioning. Results from conditioned rabbits were compared to those obtained from yoked pseudo-conditioned control rabbits. Results reveal continued learning-specific hippocampal activity one month after initial acquisition of the task. Our findings yield insight into the normal physiological responses of the hippocampus during memory processes and provide compelling in vivo electrophysiological evidence that the hippocampus is involved in both acquisition and retrieval of consolidated memories. © 2014 The Authors Hippocampus Published by Wiley Periodicals, Inc.

Double Dissociation of Amygdala and Hippocampal Contributions to Trace and Delay Fear Conditioning

PubMed Central

Raybuck, Jonathan D.; Lattal, K. Matthew

2011-01-01

A key finding in studies of the neurobiology of learning memory is that the amygdala is critically involved in Pavlovian fear conditioning. This is well established in delay-cued and contextual fear conditioning; however, surprisingly little is known of the role of the amygdala in trace conditioning. Trace fear conditioning, in which the CS and US are separated in time by a trace interval, requires the hippocampus and prefrontal cortex. It is possible that recruitment of cortical structures by trace conditioning alters the role of the amygdala compared to delay fear conditioning, where the CS and US overlap. To investigate this, we inactivated the amygdala of male C57BL/6 mice with GABA A agonist muscimol prior to 2-pairing trace or delay fear conditioning. Amygdala inactivation produced deficits in contextual and delay conditioning, but had no effect on trace conditioning. As controls, we demonstrate that dorsal hippocampal inactivation produced deficits in trace and contextual, but not delay fear conditioning. Further, pre- and post-training amygdala inactivation disrupted the contextual but the not cued component of trace conditioning, as did muscimol infusion prior to 1- or 4-pairing trace conditioning. These findings demonstrate that insertion of a temporal gap between the CS and US can generate amygdala-independent fear conditioning. We discuss the implications of this surprising finding for current models of the neural circuitry involved in fear conditioning. PMID:21283812

Automatic Removal of Physiological Artifacts in EEG: The Optimized Fingerprint Method for Sports Science Applications

PubMed Central

Stone, David B.; Tamburro, Gabriella; Fiedler, Patrique; Haueisen, Jens; Comani, Silvia

2018-01-01

Data contamination due to physiological artifacts such as those generated by eyeblinks, eye movements, and muscle activity continues to be a central concern in the acquisition and analysis of electroencephalographic (EEG) data. This issue is further compounded in EEG sports science applications where the presence of artifacts is notoriously difficult to control because behaviors that generate these interferences are often the behaviors under investigation. Therefore, there is a need to develop effective and efficient methods to identify physiological artifacts in EEG recordings during sports applications so that they can be isolated from cerebral activity related to the activities of interest. We have developed an EEG artifact detection model, the Fingerprint Method, which identifies different spatial, temporal, spectral, and statistical features indicative of physiological artifacts and uses these features to automatically classify artifactual independent components in EEG based on a machine leaning approach. Here, we optimized our method using artifact-rich training data and a procedure to determine which features were best suited to identify eyeblinks, eye movements, and muscle artifacts. We then applied our model to an experimental dataset collected during endurance cycling. Results reveal that unique sets of features are suitable for the detection of distinct types of artifacts and that the Optimized Fingerprint Method was able to correctly identify over 90% of the artifactual components with physiological origin present in the experimental data. These results represent a significant advancement in the search for effective means to address artifact contamination in EEG sports science applications. PMID:29618975

Automatic Removal of Physiological Artifacts in EEG: The Optimized Fingerprint Method for Sports Science Applications.

PubMed

Stone, David B; Tamburro, Gabriella; Fiedler, Patrique; Haueisen, Jens; Comani, Silvia

2018-01-01

Data contamination due to physiological artifacts such as those generated by eyeblinks, eye movements, and muscle activity continues to be a central concern in the acquisition and analysis of electroencephalographic (EEG) data. This issue is further compounded in EEG sports science applications where the presence of artifacts is notoriously difficult to control because behaviors that generate these interferences are often the behaviors under investigation. Therefore, there is a need to develop effective and efficient methods to identify physiological artifacts in EEG recordings during sports applications so that they can be isolated from cerebral activity related to the activities of interest. We have developed an EEG artifact detection model, the Fingerprint Method, which identifies different spatial, temporal, spectral, and statistical features indicative of physiological artifacts and uses these features to automatically classify artifactual independent components in EEG based on a machine leaning approach. Here, we optimized our method using artifact-rich training data and a procedure to determine which features were best suited to identify eyeblinks, eye movements, and muscle artifacts. We then applied our model to an experimental dataset collected during endurance cycling. Results reveal that unique sets of features are suitable for the detection of distinct types of artifacts and that the Optimized Fingerprint Method was able to correctly identify over 90% of the artifactual components with physiological origin present in the experimental data. These results represent a significant advancement in the search for effective means to address artifact contamination in EEG sports science applications.

Does trait anxiety influence effects of oxytocin on eye-blink startle reactivity? A randomized, double-blind, placebo-controlled crossover study.

PubMed

Schumacher, Sonja; Oe, Misari; Wilhelm, Frank H; Rufer, Michael; Heinrichs, Markus; Weidt, Steffi; Moergeli, Hanspeter; Martin-Soelch, Chantal

2018-01-01

Previous research has demonstrated that the neuropeptide oxytocin modulates social behaviors and reduces anxiety. However, effects of oxytocin on startle reactivity, a well-validated measure of defense system activation related to fear and anxiety, have been inconsistent. Here we investigated the influence of oxytocin on startle reactivity with particular focus on the role of trait anxiety. Forty-four healthy male participants attended two experimental sessions. They received intranasal oxytocin (24 IU) in one session and placebo in the other. Startle probes were presented in combination with pictures of social and non-social content. Eye-blink startle magnitude was measured by electromyography over the musculus orbicularis oculi in response to 95 dB noise bursts. Participants were assigned to groups of high vs. low trait anxiety based on their scores on the trait form of the Spielberger State-Trait Anxiety Inventory (STAI). A significant interaction effect of oxytocin with STAI confirmed that trait anxiety moderated the effect of oxytocin on startle reactivity. Post-hoc tests indicated that for participants with elevated trait anxiety, oxytocin increased startle magnitude, particularly when watching non-social pictures, while this was not the case for participants with low trait anxiety. Results indicate that effects of oxytocin on defense system activation depend on individual differences in trait anxiety. Trait anxiety may be an important moderator variable that should be considered in human studies on oxytocin effects.

Local and global stability for Lotka-Volterra systems with distributed delays and instantaneous negative feedbacks

NASA Astrophysics Data System (ADS)

Faria, Teresa; Oliveira, José J.

This paper addresses the local and global stability of n-dimensional Lotka-Volterra systems with distributed delays and instantaneous negative feedbacks. Necessary and sufficient conditions for local stability independent of the choice of the delay functions are given, by imposing a weak nondelayed diagonal dominance which cancels the delayed competition effect. The global asymptotic stability of positive equilibria is established under conditions slightly stronger than the ones required for the linear stability. For the case of monotone interactions, however, sharper conditions are presented. This paper generalizes known results for discrete delays to systems with distributed delays. Several applications illustrate the results.

Delayed Face Recognition in Children and Adolescents with Autism Spectrum Disorders

PubMed Central

Tehrani-Doost, Mehdi; Ghanbari-Motlagh, Maria; Shahrivar, Zahra

2012-01-01

Objective Children with autism spectrum disorders (ASDs) have great problems in social interactions including face recognition. There are many studies reporting deficits in face memory in individuals with ASDs. On the other hand, some studies indicate that this kind of memory is intact in this group. In the present study, delayed face recognition has been investigated in children and adolescents with ASDs compared to the age and sex matched typically developing group. Methods In two sessions, Benton Facial Recognition Test was administered to 15 children and adolescents with ASDs (high functioning autism and Asperger syndrome) and to 15 normal participants, ages 8-17 years. In the first condition, the long form of Benton Facial Recognition Test was used without any delay. In the second session, this test was administered with 15 seconds delay after one week. The reaction times and correct responses were measured in both conditions as the dependent variables. Results Comparison of the reaction times and correct responses in the two groups revealed no significant difference in delayed and non-delayed conditions. Furthermore, no significant difference was observed between the two conditions in ASDs patients when comparing the variables. Although a significant correlation (p<0.05) was found between delayed and non-delayed conditions, it was not significant in the normal group. Moreover, data analysis revealed no significant difference between the two groups in the two conditions when the IQ was considered as covariate. Conclusion In this study, it was found that the ability to recognize faces in simultaneous and delayed conditions is similar between adolescents with ASDs and their normal counterparts. PMID:22952545

Role of the serotonin 5-HT(2A) receptor in learning.

PubMed

Harvey, John A

2003-01-01

This study reviews the role of the serotonin 5-HT2A receptor in learning as measured by the acquisition of the rabbit's classically conditioning nictitating membrane response, a component of the eyeblink response. Agonists at the 5-HT2A receptor including LSD (d-lysergic acid diethylamide) enhanced associative learning at doses that produce cognitive effects in humans. Some antagonists such as BOL (d-bromolysergic acid diethylamide), LY53,857, and ketanserin acted as neutral antagonists in that they had no effect on learning, whereas others (MDL11,939, ritanserin, and mianserin) acted as inverse agonists in that they retarded learning through an action at the 5-HT2A receptor. These results were placed in the context of what is known concerning the anatomical distribution and electrophysiological effects of 5-HT2A receptor activation in frontal cortex and hippocampus, as well as the role of cortical 5-HT2A receptors in schizophrenia. It was concluded that the 5-HT2A receptor demonstrates constitutive activity, and that variations in this activity can produce profound alterations in cognitive states.

Anticipation of interoceptive threat in highly anxiety sensitive persons.

PubMed

Melzig, Christiane A; Michalowski, Jaroslaw M; Holtz, Katharina; Hamm, Alfons O

2008-10-01

Anticipatory anxiety plays a major role in the etiology of panic disorder. Although anticipatory anxiety elicited by expectation of interoceptive cues is specifically relevant for panic patients, it has rarely been studied. Using a population analogue in high fear of such interoceptive arousal sensations (highly anxiety sensitive persons) we evaluated a new experimental paradigm to assess anticipatory anxiety during anticipation of interoceptive (somatic sensations evoked by hyperventilation) and exteroceptive (electric shock) threat. Symptom reports, autonomic arousal, and defensive response mobilization (startle eyeblink response) were monitored during threat and matched safe conditions in 26 highly anxiety sensitive persons and 22 controls. The anticipation of exteroceptive threat led to a defensive and autonomic mobilization as indexed by a potentiation of the startle response and an increase in skin conductance level in both experimental groups. During interoceptive threat, however, only highly anxiety sensitive persons but not the controls exhibited a startle response potentiation as well as autonomic activation. The anticipation of a hyperventilation procedure thus seems a valid paradigm to investigate anticipatory anxiety elicited by interoceptive cues in the clinical context.

Role of motor cortex NMDA receptors in learning-dependent synaptic plasticity of behaving mice

PubMed Central

Hasan, Mazahir T.; Hernández-González, Samuel; Dogbevia, Godwin; Treviño, Mario; Bertocchi, Ilaria; Gruart, Agnès; Delgado-García, José M.

2013-01-01

The primary motor cortex has an important role in the precise execution of learned motor responses. During motor learning, synaptic efficacy between sensory and primary motor cortical neurons is enhanced, possibly involving long-term potentiation and N-methyl-D-aspartate (NMDA)-specific glutamate receptor function. To investigate whether NMDA receptor in the primary motor cortex can act as a coincidence detector for activity-dependent changes in synaptic strength and associative learning, here we generate mice with deletion of the Grin1 gene, encoding the essential NMDA receptor subunit 1 (GluN1), specifically in the primary motor cortex. The loss of NMDA receptor function impairs primary motor cortex long-term potentiation in vivo. Importantly, it impairs the synaptic efficacy between the primary somatosensory and primary motor cortices and significantly reduces classically conditioned eyeblink responses. Furthermore, compared with wild-type littermates, mice lacking primary motor cortex show slower learning in Skinner-box tasks. Thus, primary motor cortex NMDA receptors are necessary for activity-dependent synaptic strengthening and associative learning. PMID:23978820

Robustness of delayed multistable systems with application to droop-controlled inverter-based microgrids

NASA Astrophysics Data System (ADS)

Efimov, Denis; Schiffer, Johannes; Ortega, Romeo

2016-05-01

Motivated by the problem of phase-locking in droop-controlled inverter-based microgrids with delays, the recently developed theory of input-to-state stability (ISS) for multistable systems is extended to the case of multistable systems with delayed dynamics. Sufficient conditions for ISS of delayed systems are presented using Lyapunov-Razumikhin functions. It is shown that ISS multistable systems are robust with respect to delays in a feedback. The derived theory is applied to two examples. First, the ISS property is established for the model of a nonlinear pendulum and delay-dependent robustness conditions are derived. Second, it is shown that, under certain assumptions, the problem of phase-locking analysis in droop-controlled inverter-based microgrids with delays can be reduced to the stability investigation of the nonlinear pendulum. For this case, corresponding delay-dependent conditions for asymptotic phase-locking are given.

DISCRIMINATION ACQUISITION IN CHILDREN WITH DEVELOPMENTAL DISABILITIES UNDER IMMEDIATE AND DELAYED REINFORCEMENT

PubMed Central

Sy, Jolene R.; Vollmer, Timothy R.

2012-01-01

We evaluated the discrimination acquisition of individuals with developmental disabilities under immediate and delayed reinforcement. In Experiment 1, discrimination between two alternatives was examined when reinforcement was immediate or delayed by 20 s, 30 s, or 40 s. In Experiment 2, discrimination between 2 alternatives was compared across an immediate reinforcement condition and a delayed reinforcement condition in which subjects could respond during the delay. In Experiment 3, discrimination among 4 alternatives was compared across immediate and delayed reinforcement. In Experiment 4, discrimination between 2 alternatives was examined when reinforcement was immediate and 0-s or 30-s intertrial intervals (ITI) were programmed. For most subjects, discrimination acquisition occurred under immediate reinforcement. However, for some subjects, introducing delays slowed or prevented discrimination acquisition under some conditions. Results from Experiment 4 suggest that longer ITIs cannot account for the lack of discrimination under delayed reinforcement. PMID:23322925

Delay-range-dependent chaos synchronization approach under varying time-lags and delayed nonlinear coupling.

PubMed

Zaheer, Muhammad Hamad; Rehan, Muhammad; Mustafa, Ghulam; Ashraf, Muhammad

2014-11-01

This paper proposes a novel state feedback delay-range-dependent control approach for chaos synchronization in coupled nonlinear time-delay systems. The coupling between two systems is esteemed to be nonlinear subject to time-lags. Time-varying nature of both the intrinsic and the coupling delays is incorporated to broad scope of the present study for a better-quality synchronization controller synthesis. Lyapunov-Krasovskii (LK) functional is employed to derive delay-range-dependent conditions that can be solved by means of the conventional linear matrix inequality (LMI)-tools. The resultant control approach for chaos synchronization of the master-slave time-delay systems considers non-zero lower bound of the intrinsic as well as the coupling time-delays. Further, the delay-dependent synchronization condition has been established as a special case of the proposed LK functional treatment. Furthermore, a delay-range-dependent condition, independent of the delay-rate, has been provided to address the situation when upper bound of the delay-derivative is unknown. A robust state feedback control methodology is formulated for synchronization of the time-delay chaotic networks against the L2 norm bounded perturbations by minimizing the L2 gain from the disturbance to the synchronization error. Numerical simulation results are provided for the time-delay chaotic networks to show effectiveness of the proposed delay-range-dependent chaos synchronization methodologies. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Lock-and-key mechanisms of cerebellar memory recall based on rebound currents.

PubMed

Wetmore, Daniel Z; Mukamel, Eran A; Schnitzer, Mark J

2008-10-01

A basic question for theories of learning and memory is whether neuronal plasticity suffices to guide proper memory recall. Alternatively, information processing that is additional to readout of stored memories might occur during recall. We formulate a "lock-and-key" hypothesis regarding cerebellum-dependent motor memory in which successful learning shapes neural activity to match a temporal filter that prevents expression of stored but inappropriate motor responses. Thus, neuronal plasticity by itself is necessary but not sufficient to modify motor behavior. We explored this idea through computational studies of two cerebellar behaviors and examined whether deep cerebellar and vestibular nuclei neurons can filter signals from Purkinje cells that would otherwise drive inappropriate motor responses. In eyeblink conditioning, reflex acquisition requires the conditioned stimulus (CS) to precede the unconditioned stimulus (US) by >100 ms. In our biophysical models of cerebellar nuclei neurons this requirement arises through the phenomenon of postinhibitory rebound depolarization and matches longstanding behavioral data on conditioned reflex timing and reliability. Although CS-US intervals<100 ms may induce Purkinje cell plasticity, cerebellar nuclei neurons drive conditioned responses only if the CS-US training interval was >100 ms. This bound reflects the minimum time for deinactivation of rebound currents such as T-type Ca2+. In vestibulo-ocular reflex adaptation, hyperpolarization-activated currents in vestibular nuclei neurons may underlie analogous dependence of adaptation magnitude on the timing of visual and vestibular stimuli. Thus, the proposed lock-and-key mechanisms link channel kinetics to recall performance and yield specific predictions of how perturbations to rebound depolarization affect motor expression.

Empirically based comparisons of the reliability and validity of common quantification approaches for eyeblink startle potentiation in humans

PubMed Central

Bradford, Daniel E.; Starr, Mark J.; Shackman, Alexander J.

2015-01-01

Abstract Startle potentiation is a well‐validated translational measure of negative affect. Startle potentiation is widely used in clinical and affective science, and there are multiple approaches for its quantification. The three most commonly used approaches quantify startle potentiation as the increase in startle response from a neutral to threat condition based on (1) raw potentiation, (2) standardized potentiation, or (3) percent‐change potentiation. These three quantification approaches may yield qualitatively different conclusions about effects of independent variables (IVs) on affect when within‐ or between‐group differences exist for startle response in the neutral condition. Accordingly, we directly compared these quantification approaches in a shock‐threat task using four IVs known to influence startle response in the no‐threat condition: probe intensity, time (i.e., habituation), alcohol administration, and individual differences in general startle reactivity measured at baseline. We confirmed the expected effects of time, alcohol, and general startle reactivity on affect using self‐reported fear/anxiety as a criterion. The percent‐change approach displayed apparent artifact across all four IVs, which raises substantial concerns about its validity. Both raw and standardized potentiation approaches were stable across probe intensity and time, which supports their validity. However, only raw potentiation displayed effects that were consistent with a priori specifications and/or the self‐report criterion for the effects of alcohol and general startle reactivity. Supplemental analyses of reliability and validity for each approach provided additional evidence in support of raw potentiation. PMID:26372120

Effects of amphetamine on delay discounting in rats depend upon the manner in which delay is varied

PubMed Central

Maguire, David R; Henson, Cedric; France, Charles P

2014-01-01

Whether stimulant drugs like amphetamine increase or decrease choice of larger delayed reinforcers over smaller immediately available reinforcers under delay discounting procedures can depend on several factors, including the order in which delay is presented. This study examined whether the order of delay presentation impacts drug effects on discounting in rats (n=8) trained and tested under an ascending order, a descending order, as well as under a fixed delay condition. Responses on one lever delivered 1 food pellet immediately and responses on the other lever delivered 3 food pellets immediately or after a delay (4–32 s). In Experiment 1, the delay to the larger reinforcer varied within session and the order of delay presentation (ascending or descending) varied across conditions. In Experiment 2, the same delay value was presented in all blocks of the session (i.e., delay was fixed), and delay varied across phases. Under the ascending order of delay, amphetamine (0.32–1.78 mg/kg) increased choice of the larger reinforcer in some rats and decreased choice in others. In the same rats responding under the descending and fixed delay conditions, amphetamine markedly decreased choice of the larger reinforcer even in the component associated with no delay. In some subjects, the effects of amphetamine differed depending on the manner in which delay was presented, indicating that drug-induced changes in performance were due, in part, to mechanisms other than altered sensitivity to reinforcer delay. These results also suggest that a history of responding under both orders of delay presentation can modulate drug effects. PMID:24780379

Human self-control and the density of reinforcement

PubMed Central

Flora, Stephen R.; Pavlik, William B.

1992-01-01

Choice responding in adult humans on a discrete-trial button-pressing task was examined as a function of amount, delay, and overall density (points per unit time) of reinforcement. Reinforcement consisted of points that were exchangeable for money. In T 0 conditions, an impulsive response produced 4 points immediately and a self-control response produced 10 points after a delay of 15 s. In T 15 conditions, a constant delay of 15 s was added to both prereinforcer delays. Postreinforcer delays, which consisted of 15 s added to the end of each impulsive trial, equated trial durations regardless of choice, and was manipulated in both T 0 and T 15 conditions. In all conditions, choice was predicted directly from the relative reinforcement densities of the alternatives. Self-control was observed in all conditions except T 0 without postreinforcer delays, where the impulsive choices produced the higher reinforcement density. These results support previous studies showing that choice is a direct function of the relative reinforcement densities when conditioned (point) reinforcers are used. In contrast, where responding produces intrinsic (immediately consumable) reinforcers, immediacy of reinforcement appears to account for preference when density does not. PMID:16812652

Effect of facial self-resemblance on the startle response and subjective ratings of erotic stimuli in heterosexual men.

PubMed

Lass-Hennemann, Johanna; Deuter, Christian E; Kuehl, Linn K; Schulz, Andre; Blumenthal, Terry D; Schachinger, Hartmut

2011-10-01

Cues of kinship are predicted to increase prosocial behavior due to the benefits of inclusive fitness, but to decrease approach motivation due to the potential costs of inbreeding. Previous studies have shown that facial resemblance, a putative cue of kinship, increases prosocial behavior. However, the effects of facial resemblance on mating preferences are equivocal, with some studies finding that facial resemblance decreases sexual attractiveness ratings, while other studies show that individuals choose mates partly on the basis of similarity. To further investigate this issue, a psychophysiological measure of affective processing, the startle response, was used in this study, assuming that differences in approach motivation to erotic pictures will modulate startle. Male volunteers (n = 30) viewed 30 pictures of erotic female nudes while startle eyeblink responses were elicited by acoustic noise probes. The female nude pictures were digitally altered so that the face either resembled the male participant or another participant, or were not altered. Non-nude neutral pictures were also included. Importantly, the digital alteration was undetected by the participants. Erotic pictures were rated as being pleasant and clearly reduced startle eyeblink magnitude as compared to neutral pictures. Participants showed greater startle inhibition to self-resembling than to other-resembling or non-manipulated female nude pictures, but subjective pleasure and arousal ratings did not differ among the three erotic picture categories. Our data suggest that visual facial resemblance of opposite-sex nudes increases approach motivation in men, and that this effect was not due to their conscious evaluation of the erotic stimuli.

A comparison of pecking generated by serial, delay, and trace autoshaping procedures1

PubMed Central

Newlin, Robert J.; LoLordo, Vincent M.

1976-01-01

Pigeons were exposed to serial, delay, and trace autoshaping procedures. In Experiment I, all conditioned stimuli (CSs) were changes in illumination of the response key. The number of trials to acquisition of the keypeck increased from serial, to 4-sec delay, 8-sec delay, and 8-sec trace procedures, in that order. In Experiment II, which used a longer intertrial interval, trials to criterion increased from 8-sec delay, to 28-sec delay, 8-sec trace, and 28-sec trace procedures, in that order. In Experiment III, two groups received serial procedures in which the first CS was either a tone or a houselight, and the second was a keylight. The tone group acquired the key peck more rapidly than the houselight group. Early in conditioning in these experiments, and when the conditioned stimulus was a change in the keylight, there was a short latency to the onset of pecking and pecking was directed at the CS. After extensive conditioning, or when the CS was relatively diffuse, pecking still occurred, but had a longer latency and was not reliably directed toward the conditioned stimulus. PMID:16811907

Profitless delays for extinction in nonautonomous Lotka-Volterra system

NASA Astrophysics Data System (ADS)

Liu, Shengqiang; Chen, Lansun

2001-12-01

We study the delayed periodic n-species Lotka-Voterra systems where the growth rate of each species is not always positive. The sufficient conditions for the extinction that are independent of the delays are obtained. Some known results are improved and generalized. Our results suggest that under some conditions, the introduction and the variance of the time delays can be both harmless and profitless. Discussion about the effect of time delays on the extinction of the system is also advanced.

Stability analysis of fractional-order Hopfield neural networks with time delays.

PubMed

Wang, Hu; Yu, Yongguang; Wen, Guoguang

2014-07-01

This paper investigates the stability for fractional-order Hopfield neural networks with time delays. Firstly, the fractional-order Hopfield neural networks with hub structure and time delays are studied. Some sufficient conditions for stability of the systems are obtained. Next, two fractional-order Hopfield neural networks with different ring structures and time delays are developed. By studying the developed neural networks, the corresponding sufficient conditions for stability of the systems are also derived. It is shown that the stability conditions are independent of time delays. Finally, numerical simulations are given to illustrate the effectiveness of the theoretical results obtained in this paper. Copyright © 2014 Elsevier Ltd. All rights reserved.

Phase-space dissimilarity measures for industrial and biomedical applications

NASA Astrophysics Data System (ADS)

Protopopescu, V. A.; Hively, L. M.

2005-12-01

One of the most important problems in time-series analysis is the suitable characterization of the dynamics for timely, accurate, and robust condition assessment of the underlying system. Machine and physiological processes display complex, non-stationary behaviors that are affected by noise and may range from (quasi-)periodic to completely irregular (chaotic) regimes. Nevertheless, extensive experimental evidence indicates that even when the systems behave very irregularly (e.g., severe tool chatter or cardiac fibrillation), one may assume that - for all practical purposes - the dynamics are confined to low dimensional manifolds. As a result, the behavior of these systems can be described via traditional nonlinear measures (TNM), such as Lyapunov exponents, Kolmogorov entropy, and correlation dimension. While these measures are adequate for discriminating between clear-cut regular and chaotic dynamics, they are not sufficiently sensitive to distinguish between slightly different irregular (chaotic) regimes, especially when data are noisy and/or limited. Both machine and physiological dynamics usually fall into this latter category, creating a massive stumbling block to prognostication of abnormal regimes. We present here a recently developed approach that captures more efficiently changes in the underlying dynamics. We start with process-indicative, time-serial data that are checked for quality and discarded if inadequate. Acceptable data are filtered to remove confounding artifacts (e.g., sinusoidal variation in three-phase electrical signals or eye-blinks and muscular activity in EEG). The artifact-filtered data are then used to recover the essential features of the underlying dynamics via standard time-delay, phase-space reconstruction. One of the main results of this reconstruction is a discrete approximation of the distribution function (DF) on the attractor. Unaltered dynamics yield an unchanging geometry of the attractor and the visitation frequencies of its various points, corresponding to the baseline DF. Condition change is established by comparing the base line DFs to subsequent test case DFs via new, phase space dissimilarity measures (PSDM), namely the distance and - square statistics between two DFs. A clear trend in the dissimilarity measures over time indicates substantial departure from the baseline dynamics, thus signaling condition change. The severity of this departure can be interpreted as a "normal" fluctuation, abnormal behavior, impending failure, or complete breakdown. We illustrate the new approach on an assortment of machinery and biomedical examples. The machine data were collected during laboratory tests on industrial equipment, for diverse failure modes, via seeded faults and accelerated failures. The biomedical applications involve detection of physiological changes, such as epileptic seizures from EEG; ventricular fibrillation, fainting, and sepsis onset from ECG; and breathing difficulty from chest sounds. The PSDM show a consistent discrimination of normal-to-abnormal transitions, allowing earlier, more accurate, and more robust detection of the dynamical change for all of these applications in comparison to TNM.

Impulsive-choice patterns for food in genetically lean and obese Zucker rats

PubMed Central

Boomhower, Steven R.; Rasmussen, Erin B.; Doherty, Tiffany S.

2012-01-01

Behavioral-economic studies have shown that differences between lean and obese Zuckers in food consumption depend on the response requirement for food. Since a response requirement inherently increases the delay to reinforcement, differences in sensitivity to delay may also be a relevant mechanism of food consumption in the obese Zucker rat. Furthermore, the endocannabinoid neurotransmitter system has been implicated in impulsivity, but studies that attempt to characterize the effects of cannabinoid drugs (e.g., rimonabant) on impulsive choice may be limited by floor effects. The present study aimed to characterize impulsive-choice patterns for sucrose using an adjusting-delay procedure in genetically lean and obese Zuckers. Ten lean and ten obese Zucker rats chose between one lever that resulted in one pellet after a standard delay (either 1 s or 5 s) and a second lever that resulted in two or three pellets after an adjusting delay. After behavior stabilized under baseline, rimonabant (0–10 mg/kg) was administered prior to some choice sessions in the two-pellet condition. Under baseline, obese Zuckers made more impulsive choices than leans in three of the four standard-delay/pellet conditions. Additionally, in the 2-pellet condition, rimonabant increased impulsive choice in lean rats in the 1-s standard-delay condition; however, rimonabant decreased impulsive choice in obese rats in the 1-s and 5-s standard-delay conditions. These data suggest that genetic factors that influence impulsive choice are stronger in some choice conditions than others, and that the endocannabinoid system may be a relevant neuromechanism. PMID:23261877

Impulsive-choice patterns for food in genetically lean and obese Zucker rats.

PubMed

Boomhower, Steven R; Rasmussen, Erin B; Doherty, Tiffany S

2013-03-15

Behavioral-economic studies have shown that differences between lean and obese Zuckers in food consumption depend on the response requirement for food. Since a response requirement inherently increases the delay to reinforcement, differences in sensitivity to delay may also be a relevant mechanism of food consumption in the obese Zucker rat. Furthermore, the endocannabinoid neurotransmitter system has been implicated in impulsivity, but studies that attempt to characterize the effects of cannabinoid drugs (e.g., rimonabant) on impulsive choice may be limited by floor effects. The present study aimed to characterize impulsive-choice patterns for sucrose using an adjusting-delay procedure in genetically lean and obese Zuckers. Ten lean and ten obese Zucker rats chose between one lever that resulted in one pellet after a standard delay (either 1 s or 5 s) and a second lever that resulted in two or three pellets after an adjusting delay. After behavior stabilized under baseline, rimonabant (0-10 mg/kg) was administered prior to some choice sessions in the two-pellet condition. Under baseline, obese Zuckers made more impulsive choices than leans in three of the four standard-delay/pellet conditions. Additionally, in the 2-pellet condition, rimonabant increased impulsive choice in lean rats in the 1-s standard-delay condition; however, rimonabant decreased impulsive choice in obese rats in the 1-s and 5-s standard-delay conditions. These data suggest that genetic factors that influence impulsive choice are stronger in some choice conditions than others, and that the endocannabinoid system may be a relevant neuromechanism. Copyright © 2012 Elsevier B.V. All rights reserved.

Self-regulation strategies may enhance the acute effect of exercise on smoking delay.

PubMed

Hatzigeorgiadis, Antonis; Pappa, Vassiliki; Tsiami, Anastasia; Tzatzaki, Theodora; Georgakouli, Kalliopi; Zourbanos, Nikos; Goudas, Marios; Chatzisarantis, Nikos; Theodorakis, Yannis

2016-06-01

The present study examined the acute effect of a moderate intensity aerobic exercise session combined with self-regulation on smoking delay in physically inactive smokers. Participants were 11 adults (5 males and 6 females) that completed three experimental conditions: control, exercise, and exercise using self-regulation strategies (SR). Following the experimental treatment smoking for the two exercise conditions delayed significantly more than for the control condition; in addition exercise SR delayed smoking marginally more that the plain exercise condition. Findings supported previous research that acute exercise reduces cravings to smoke, and suggests that the use of self-regulation strategies may strengthen exercise for smoking cessation interventions. Copyright © 2016 Elsevier Ltd. All rights reserved.

A technology-assisted learning setup as assessment supplement for three persons with a diagnosis of post-coma vegetative state and pervasive motor impairment.

PubMed

Lancioni, Giulio E; Singh, Nirbhay N; O'Reilly, Mark F; Sigafoos, Jeff; Buonocunto, Francesca; Sacco, Valentina; Colonna, Fabio; Navarro, Jorge; Lanzilotti, Crocifissa; Bosco, Andrea; Megna, Gianfranco; De Tommaso, Marina

2009-01-01

Post-coma persons in an apparent condition of vegetative state and pervasive motor impairment pose serious problems in terms of assessment and intervention options. A technology-based learning assessment procedure might serve for them as a diagnostic supplement with possible implications for rehabilitation intervention. The learning assessment procedure adopted in this study relied on hand-closure and eye-blinking responses and on microswitch technology to detect such responses and to present stimuli. Three participants were involved in the study. The technology consisted of a touch/pressure sensor fixed on the hand or an optic sensor mounted on an eyeglasses' frame, which were combined with a control system linked to stimulus sources. The study adopted an ABABCB sequence, in which A represented baseline periods, B intervention periods with stimuli contingent on the responses, and C a control condition with stimuli presented non-contingently. Data showed that the level of responding during the B phases was significantly higher than the levels observed during the A phases as well as the C phase for two of the three participants (i.e., indicating clear signs of learning by them). Learning might be deemed to represent basic levels of knowledge/consciousness. Thus, detecting signs of learning might help one revise a previous diagnosis of vegetative state with wide implications for rehabilitation perspectives.

Beta activity in the premotor cortex is increased during stabilized as compared to normal walking

PubMed Central

Bruijn, Sjoerd M.; Van Dieën, Jaap H.; Daffertshofer, Andreas

2015-01-01

Walking on two legs is inherently unstable. Still, we humans perform remarkable well at it, mostly without falling. To gain more understanding of the role of the brain in controlling gait stability we measured brain activity using electro-encephalography (EEG) during stabilized and normal walking. Subjects walked on a treadmill in two conditions, each lasting 10 min; normal, and while being laterally stabilized by elastic cords. Kinematics of trunk and feet, electro-myography (EMG) of neck muscles, as well as 64-channel EEG were recorded. To assess gait stability the local divergence exponent, step width, and trunk range of motion were calculated from the kinematic data. We used independent component (IC) analysis to remove movement, EMG, and eyeblink artifacts from the EEG, after which dynamic imaging of coherent sources beamformers were determined to identify cortical sources that showed a significant difference between conditions. Stabilized walking led to a significant increase in gait stability, i.e., lower local divergence exponents. Beamforming analysis of the beta band activity revealed significant sources in bilateral pre-motor cortices. Projection of sensor data on these sources showed a significant difference only in the left premotor area, with higher beta power during stabilized walking, specifically around push-off, although only significant around contralateral push-off. It appears that even during steady gait the cortex is involved in the control of stability. PMID:26578937

Phase matters: responding to and learning about peripheral stimuli depends on hippocampal θ phase at stimulus onset

PubMed Central

Waselius, Tomi; Mikkonen, Jarno E.; Wikgren, Jan; Penttonen, Markku

2015-01-01

Hippocampal θ (3–12 Hz) oscillations are implicated in learning and memory, but their functional role remains unclear. We studied the effect of the phase of local θ oscillation on hippocampal responses to a neutral conditioned stimulus (CS) and subsequent learning of classical trace eyeblink conditioning in adult rabbits. High-amplitude, regular hippocampal θ-band responses (that predict good learning) were elicited by the CS when it was timed to commence at the fissure θ trough (Trough group). Regardless, learning in this group was not enhanced compared with a yoked control group, possibly due to a ceiling effect. However, when the CS was consistently presented to the peak of θ (Peak group), hippocampal θ-band responding was less organized and learning was retarded. In well-trained animals, the hippocampal θ phase at CS onset no longer affected performance of the learned response, suggesting a time-limited role for hippocampal processing in learning. To our knowledge, this is the first study to demonstrate that timing a peripheral stimulus to a specific phase of the hippocampal θ cycle produces robust effects on the synchronization of neural responses and affects learning at the behavioral level. Our results support the notion that the phase of spontaneous hippocampal θ oscillation is a means of regulating the processing of information in the brain to a behaviorally relevant degree. PMID:25979993

Cognitive abnormalities and hippocampal alterations in monoamine oxidase A and B knockout mice

PubMed Central

Singh, Chanpreet; Bortolato, Marco; Bali, Namrata; Godar, Sean C.; Scott, Anna L.; Chen, Kevin; Thompson, Richard F.; Shih, Jean C.

2013-01-01

The monoamine oxidase isoenzymes (MAOs) A and B play important roles in the homeostasis of monoaminergic neurotransmitters. The combined deficiency of MAO A and B results in significantly elevated levels of serotonin (5-hydroxytryptamine), norepinephrine, dopamine, and β-phenylethylamine; in humans and mice, these neurochemical changes are accompanied by neurodevelopmental perturbations as well as autistic-like responses. Ample evidence indicates that normal levels of monoamines in the hippocampus, amygdala, frontal cortex, and cerebellum are required for the integrity of learning and memory. Thus, in the present study, the cognitive status of MAO A/B knockout (KO) mice was examined with a wide array of behavioral tests. In comparison with male wild-type littermates, MAO A/B KO mice exhibited abnormally high and overgeneralized fear conditioning and enhanced eye-blink conditioning. These alterations were accompanied by significant increases in hippocampal long-term potentiation and alterations in the relative expression of NMDA glutamate receptor subunits. Our data suggest that chronic elevations of monoamines, because of the absence of MAO A and MAO B, cause functional alterations that are accompanied with changes in the cellular mechanisms underlying learning and memory. The characteristics exhibited by MAO A/B KO mice highlight the potential of these animals as a useful tool to provide further insight into the molecular bases of disorders associated with abnormal monoaminergic profiles. PMID:23858446

Cognitive abnormalities and hippocampal alterations in monoamine oxidase A and B knockout mice.

PubMed

Singh, Chanpreet; Bortolato, Marco; Bali, Namrata; Godar, Sean C; Scott, Anna L; Chen, Kevin; Thompson, Richard F; Shih, Jean C

2013-07-30

The monoamine oxidase isoenzymes (MAOs) A and B play important roles in the homeostasis of monoaminergic neurotransmitters. The combined deficiency of MAO A and B results in significantly elevated levels of serotonin (5-hydroxytryptamine), norepinephrine, dopamine, and β-phenylethylamine; in humans and mice, these neurochemical changes are accompanied by neurodevelopmental perturbations as well as autistic-like responses. Ample evidence indicates that normal levels of monoamines in the hippocampus, amygdala, frontal cortex, and cerebellum are required for the integrity of learning and memory. Thus, in the present study, the cognitive status of MAO A/B knockout (KO) mice was examined with a wide array of behavioral tests. In comparison with male wild-type littermates, MAO A/B KO mice exhibited abnormally high and overgeneralized fear conditioning and enhanced eye-blink conditioning. These alterations were accompanied by significant increases in hippocampal long-term potentiation and alterations in the relative expression of NMDA glutamate receptor subunits. Our data suggest that chronic elevations of monoamines, because of the absence of MAO A and MAO B, cause functional alterations that are accompanied with changes in the cellular mechanisms underlying learning and memory. The characteristics exhibited by MAO A/B KO mice highlight the potential of these animals as a useful tool to provide further insight into the molecular bases of disorders associated with abnormal monoaminergic profiles.

A Demonstration of Precise Calibration of Tropospheric Delay Fluctuations with Water Vapor Radiometers

NASA Technical Reports Server (NTRS)

Teitelbaum, L. P.; Keihm, S. J.; Linfield, R. P.; Mahoney, M. J.; Resch, G. M.

1996-01-01

The ability of water vapor radiometers (WVRs) to calibrate changes in tropospheric delay was demonstrated during very long baseline radio interferometer (VLBI) observations at Goldstone, California. WVR measurements reduced the observed VLBI delay variations over a 13 hr period by a factor of approx. = 2.5. When applied to shorter time scales, a approx. = 50% reduction in 100-700 s delay variations was achieved during conditions of high tropospheric activity. Thermal WVR noise precluded calibration of short time scale delay fluctuations during quiet tropospheric conditions.

Asymptotic stability of delay-difference system of hopfield neural networks via matrix inequalities and application.

PubMed

Ratchagit, Kreangkri

2007-10-01

In this paper, we derive a sufficient condition for asymptotic stability of the zero solution of delay-difference system of Hopfield neural networks in terms of certain matrix inequalities by using a discrete version of the Lyapunov second method. The result is applied to obtain new asymptotic stability condition for some class of delay-difference system such as delay-difference system of Hopfield neural networks with multiple delays in terms of certain matrix inequalities. Our results can be well suited for computational purposes.

Predicting memory performance under conditions of proactive interference: immediate and delayed judgments of learning.

PubMed

Wahlheim, Christopher N

2011-07-01

Four experiments examined the monitoring accuracy of immediate and delayed judgments of learning (JOLs) under conditions of proactive interference (PI). PI was produced using paired-associate learning tasks that conformed to variations of classic A-B, A-D paradigms. Results revealed that the relative monitoring accuracy of interference items was better for delayed than for immediate JOLs. However, delayed JOLs were overconfident for interference items, but not for items devoid of interference. Intrusions retrieved prior to delayed JOLs produced inflated predictions of performance. These results show that delayed JOLs enhance monitoring accuracy in PI situations, except when intrusions are mistaken for target responses.

Trace conditioning in insects—keep the trace!

PubMed Central

Dylla, Kristina V.; Galili, Dana S.; Szyszka, Paul; Lüdke, Alja

2013-01-01

Trace conditioning is a form of associative learning that can be induced by presenting a conditioned stimulus (CS) and an unconditioned stimulus (US) following each other, but separated by a temporal gap. This gap distinguishes trace conditioning from classical delay conditioning, where the CS and US overlap. To bridge the temporal gap between both stimuli and to form an association between CS and US in trace conditioning, the brain must keep a neural representation of the CS after its termination—a stimulus trace. Behavioral and physiological studies on trace and delay conditioning revealed similarities between the two forms of learning, like similar memory decay and similar odor identity perception in invertebrates. On the other hand differences were reported also, like the requirement of distinct brain structures in vertebrates or disparities in molecular mechanisms in both vertebrates and invertebrates. For example, in commonly used vertebrate conditioning paradigms the hippocampus is necessary for trace but not for delay conditioning, and Drosophila delay conditioning requires the Rutabaga adenylyl cyclase (Rut-AC), which is dispensable in trace conditioning. It is still unknown how the brain encodes CS traces and how they are associated with a US in trace conditioning. Insects serve as powerful models to address the mechanisms underlying trace conditioning, due to their simple brain anatomy, behavioral accessibility and established methods of genetic interference. In this review we summarize the recent progress in insect trace conditioning on the behavioral and physiological level and emphasize similarities and differences compared to delay conditioning. Moreover, we examine proposed molecular and computational models and reassess different experimental approaches used for trace conditioning. PMID:23986710

Emotional arousal predicts intertemporal choice

PubMed Central

Lempert, Karolina M.; Johnson, Eli; Phelps, Elizabeth A.

2016-01-01

People generally prefer immediate rewards to rewards received after a delay, often even when the delayed reward is larger. This phenomenon is known as temporal discounting. It has been suggested that preferences for immediate rewards may be due to their being more concrete than delayed rewards. This concreteness may evoke an enhanced emotional response. Indeed, manipulating the representation of a future reward to make it more concrete has been shown to heighten the reward’s subjective emotional intensity, making people more likely to choose it. Here we use an objective measure of arousal – pupil dilation – to investigate if emotional arousal mediates the influence of delayed reward concreteness on choice. We recorded pupil dilation responses while participants made choices between immediate and delayed rewards. We manipulated concreteness through time interval framing: delayed rewards were presented either with the date on which they would be received (e.g., “$30, May 3”; DATE condition, more concrete) or in terms of delay to receipt (e.g., “$30, 7 days; DAYS condition, less concrete). Contrary to prior work, participants were not overall more patient in the DATE condition. However, there was individual variability in response to time framing, and this variability was predicted by differences in pupil dilation between conditions. Emotional arousal increased as the subjective value of delayed rewards increased, and predicted choice of the delayed reward on each trial. This study advances our understanding of the role of emotion in temporal discounting. PMID:26882337

Characterization of Days Based On Analysis of National Airspace System Performance Metrics

NASA Technical Reports Server (NTRS)

Chatterji, Gano B.; Musaffar, Bassam; Meyn, Larry A.; Quon, Leighton K.

2006-01-01

Days of operations in the National Airspace System can be described in term of traffic demand, runway conditions, equipment outages, and surface and enroute weather conditions. These causes manifest themselves in terms of departure delays, arrival delays, enroute delays and traffic flow management delays, Traffic flow management initiatives such as, ground stops, ground delay programs, miles-in-trail restrictions, rerouting and airborne holding are imposed to balance the air traffic demand with respect to the available capacity, In order to maintain operational efficiency of the National Airspace System, the Federal Aviation Administration (FAA) maintains delay sad other statistics in the Air Traffic Operations Network (OPSNET) and the Aviation System Performance Metrics (ASPM) databases. OPSNET data includes reportable delays of fifteen minutes ox more experienced by Instrument Flight Rule (IFR) flights. Numbers of aircraft affected by departure delays, enroute delays, arrival delays and traffic flow delays are recorded in the OPSNET data. ASPM data consist of number of actual departures, number of canceled departures, percentage of on time departures, percentage of on time gate arrivals, taxi-out delays. taxi-in delays, gate delays, arrival delays and block delays. Surface conditions at the major U.S. airports are classified in terms of Instrument Meteorological Condition (IMC) and Visual Meteorological Condition (VMC) as a function of the time of the day in the ASPM data. The main objective of this paper is to use OPSNET and ASPM data to classify the days in the datasets into few distinct groups, where each group is separated from the other groups in terms of a distance metric. The motivations for classifying the days are two-fold, 1) to enable selection of days of traffic with particular operational characteristics for concept evaluation using system-wide simulation systems such as the National Aeronautics and Space Administration's Airspace Concepts Evaluation Tool (ACES) and 2) to enable evaluation of a given day with respect to the characteristics of the classified groups. The first part of the paper is devoted to the analysis of major trends seen in the OPSNET and ASPM data. The second part of the paper is devoted to describing features or measures derived from the OPSNET and ASPM data that are suitable for characterizing days, and the classification algorithm used for grouping the days. Finally, the method for evaluating the characteristics of a given day with respect to the properties of the groups is described.

High Trait Anxiety: A Challenge for Disrupting Fear Memory Reconsolidation

PubMed Central

Soeter, Marieke; Kindt, Merel

2013-01-01

Disrupting reconsolidation may be promising in the treatment of anxiety disorders but the fear-reducing effects are thus far solely demonstrated in the average organism. A relevant question is whether disrupting fear memory reconsolidation is less effective in individuals who are vulnerable to develop an anxiety disorder. By collapsing data from six previous human fear conditioning studies we tested whether trait anxiety was related to the fear-reducing effects of a pharmacological agent targeting the process of memory reconsolidation - n = 107. Testing included different phases across three consecutive days each separated by 24 h. Fear responding was measured by the eye-blink startle reflex. Disrupting the process of fear memory reconsolidation was manipulated by administering the β-adrenergic receptor antagonist propranolol HCl either before or after memory retrieval. Trait anxiety uniquely predicted the fear-reducing effects of disrupting memory reconsolidation: the higher the trait anxiety, the less fear reduction. Vulnerable individuals with the propensity to develop anxiety disorders may need higher dosages of propranolol HCl or more retrieval trials for targeting and changing fear memory. Our finding clearly demonstrates that we cannot simply translate observations from fundamental research on fear reduction in the average organism to clinical practice. PMID:24260096

High trait anxiety: a challenge for disrupting fear memory reconsolidation.

PubMed

Soeter, Marieke; Kindt, Merel

2013-01-01

Disrupting reconsolidation may be promising in the treatment of anxiety disorders but the fear-reducing effects are thus far solely demonstrated in the average organism. A relevant question is whether disrupting fear memory reconsolidation is less effective in individuals who are vulnerable to develop an anxiety disorder. By collapsing data from six previous human fear conditioning studies we tested whether trait anxiety was related to the fear-reducing effects of a pharmacological agent targeting the process of memory reconsolidation--n = 107. Testing included different phases across three consecutive days each separated by 24 h. Fear responding was measured by the eye-blink startle reflex. Disrupting the process of fear memory reconsolidation was manipulated by administering the β-adrenergic receptor antagonist propranolol HCl either before or after memory retrieval. Trait anxiety uniquely predicted the fear-reducing effects of disrupting memory reconsolidation: the higher the trait anxiety, the less fear reduction. Vulnerable individuals with the propensity to develop anxiety disorders may need higher dosages of propranolol HCl or more retrieval trials for targeting and changing fear memory. Our finding clearly demonstrates that we cannot simply translate observations from fundamental research on fear reduction in the average organism to clinical practice.

Disrupting neural activity related to awake-state sharp wave-ripple complexes prevents hippocampal learning.

PubMed

Nokia, Miriam S; Mikkonen, Jarno E; Penttonen, Markku; Wikgren, Jan

2012-01-01

Oscillations in hippocampal local-field potentials (LFPs) reflect the crucial involvement of the hippocampus in memory trace formation: theta (4-8 Hz) oscillations and ripples (~200 Hz) occurring during sharp waves are thought to mediate encoding and consolidation, respectively. During sharp wave-ripple complexes (SPW-Rs), hippocampal cell firing closely follows the pattern that took place during the initial experience, most likely reflecting replay of that event. Disrupting hippocampal ripples using electrical stimulation either during training in awake animals or during sleep after training retards spatial learning. Here, adult rabbits were trained in trace eyeblink conditioning, a hippocampus-dependent associative learning task. A bright light was presented to the animals during the inter-trial interval (ITI), when awake, either during SPW-Rs or irrespective of their neural state. Learning was particularly poor when the light was presented following SPW-Rs. While the light did not disrupt the ripple itself, it elicited a theta-band oscillation, a state that does not usually coincide with SPW-Rs. Thus, it seems that consolidation depends on neuronal activity within and beyond the hippocampus taking place immediately after, but by no means limited to, hippocampal SPW-Rs.

Physiological artifacts in scalp EEG and ear-EEG.

PubMed

Kappel, Simon L; Looney, David; Mandic, Danilo P; Kidmose, Preben

2017-08-11

A problem inherent to recording EEG is the interference arising from noise and artifacts. While in a laboratory environment, artifacts and interference can, to a large extent, be avoided or controlled, in real-life scenarios this is a challenge. Ear-EEG is a concept where EEG is acquired from electrodes in the ear. We present a characterization of physiological artifacts generated in a controlled environment for nine subjects. The influence of the artifacts was quantified in terms of the signal-to-noise ratio (SNR) deterioration of the auditory steady-state response. Alpha band modulation was also studied in an open/closed eyes paradigm. Artifacts related to jaw muscle contractions were present all over the scalp and in the ear, with the highest SNR deteriorations in the gamma band. The SNR deterioration for jaw artifacts were in general higher in the ear compared to the scalp. Whereas eye-blinking did not influence the SNR in the ear, it was significant for all groups of scalps electrodes in the delta and theta bands. Eye movements resulted in statistical significant SNR deterioration in both frontal, temporal and ear electrodes. Recordings of alpha band modulation showed increased power and coherence of the EEG for ear and scalp electrodes in the closed-eyes periods. Ear-EEG is a method developed for unobtrusive and discreet recording over long periods of time and in real-life environments. This study investigated the influence of the most important types of physiological artifacts, and demonstrated that spontaneous activity, in terms of alpha band oscillations, could be recorded from the ear-EEG platform. In its present form ear-EEG was more prone to jaw related artifacts and less prone to eye-blinking artifacts compared to state-of-the-art scalp based systems.

Changing Delay Discounting in the Light of the Competing Neurobehavioral Decision Systems Theory: A Review

ERIC Educational Resources Information Center

Koffarnus, Mikhail N.; Jarmolowicz, David P.; Mueller, E. Terry; Bickel, Warren K.

2013-01-01

Excessively devaluing delayed reinforcers co-occurs with a wide variety of clinical conditions such as drug dependence, obesity, and excessive gambling. If excessive delay discounting is a trans-disease process that underlies the choice behavior leading to these and other negative health conditions, efforts to change an individual's discount rate…

The Effect of D-Cycloserine on Immediate vs. Delayed Extinction of Learned Fear

ERIC Educational Resources Information Center

Langton, Julia M.; Richardson, Rick

2010-01-01

We compared the effect of D-cycloserine (DCS) on immediate (10 min after conditioning) and delayed (24 h after conditioning) extinction of learned fear in rats. DCS facilitated both immediate and delayed extinction when the drug was administered after extinction training. However, DCS did not facilitate immediate extinction when administered prior…

Biased Intensity Judgements of Visceral Sensations After Learning to Fear Visceral Stimuli: A Drift Diffusion Approach.

PubMed

Zaman, Jonas; Madden, Victoria J; Iven, Julie; Wiech, Katja; Weltens, Nathalie; Ly, Huynh Giao; Vlaeyen, Johan W S; Van Oudenhove, Lukas; Van Diest, Ilse

2017-10-01

A growing body of research has identified fear of visceral sensations as a potential mechanism in the development and maintenance of visceral pain disorders. However, the extent to which such learned fear affects visceroception remains unclear. To address this question, we used a differential fear conditioning paradigm with nonpainful esophageal balloon distensions of 2 different intensities as conditioning stimuli (CSs). The experiment comprised of preacquisition, acquisition, and postacquisition phases during which participants categorized the CSs with respect to their intensity. The CS+ was always followed by a painful electrical stimulus (unconditioned stimulus) during the acquisition phase and in 60% of the trials during postacquisition. The second stimulus (CS-) was never associated with pain. Analyses of galvanic skin and startle eyeblink responses as physiological markers of successful conditioning showed increased fear responses to the CS+ compared with the CS-, but only in the group with the low-intensity stimulus as CS+. Computational modeling of response times and response accuracies revealed that differential fear learning affected perceptual decision-making about the intensities of visceral sensations such that sensations were more likely to be categorized as more intense. These results suggest that associative learning might indeed contribute to visceral hypersensitivity in functional gastrointestinal disorders. This study shows that associative fear learning biases intensity judgements of visceral sensations toward perceiving such sensations as more intense. Learning-induced alterations in visceroception might therefore contribute to the development or maintenance of visceral pain. Copyright © 2017 American Pain Society. Published by Elsevier Inc. All rights reserved.

Determinants of Motion Sickness in Tilting Trains: Coriolis/Cross-Coupling Stimuli and Tilt Delay

PubMed Central

Bertolini, Giovanni; Durmaz, Meek Angela; Ferrari, Kim; Küffer, Alexander; Lambert, Charlotte; Straumann, Dominik

2017-01-01

Faster trains require tilting of the cars to counterbalance the centrifugal forces during curves. Motion sensitive passengers, however, complain of discomfort and overt motion sickness. A recent study comparing different control systems in a tilting train, suggested that the delay of car tilts relative to the curve of the track contributes to motion sickness. Other aspects of the motion stimuli, like the lateral accelerations and the car jitters, differed between the tested conditions and prevented a final conclusion on the role of tilt delay. Nineteen subjects were tested on a motorized 3D turntable that simulated the roll tilts during yaw rotations experienced on a tilting train, isolating them from other motion components. Each session was composed of two consecutive series of 12 ideal curves that were defined on the bases of recordings during an actual train ride. The simulated car tilts started either at the beginning of the curve acceleration phase (no-delay condition) or with 3 s of delay (delay condition). Motion sickness was self-assessed by each subject at the end of each series using an analog motion sickness scale. All subjects were tested in both conditions. Significant increases of motion sickness occurred after the first sequence of 12 curves in the delay condition, but not in the no-delay condition. This increase correlated with the sensitivity of motion sickness, which was self-assessed by each subject before the experiment. The second sequence of curve did not lead to a significant further increase of motion sickness in any condition. Our results demonstrate that, even if the speed and amplitude are as low as those experienced on tilting trains, a series of roll tilts with a delay relative to the horizontal rotations, isolated from other motion stimuli occurring during a travel, generate Coriolis/cross-coupling stimulations sufficient to rapidly induce motion sickness in sensitive individuals. The strength and the rapid onset of the motion sickness reported confirm that, even if the angular velocity involved are low, the Coriolis/cross-coupling resulting from the delay is a major factor in causing sickness that can be resolved by improving the tilt timing relative to the horizontal rotation originating from the curve. PMID:28555125

Super-Latent Inhibition of Conditioned Taste Preference with a Long Retention Interval

ERIC Educational Resources Information Center

De la Casa, L. G.; Marquez, R.; Lubow, R. E.

2009-01-01

A long delay inserted between conditioning and test phases of a 3-stage Latent Inhibition (LI) procedure produces differential effects on LI depending on the delay context. Thus, enhanced LI has been obtained when the delay is spent in a context that is different from the remaining experimental contexts, but not when it is the same. The present…

AD/HD and the Capture of Attention by Briefly Exposed Delay-Related Cues: Evidence from a Conditioning Paradigm

ERIC Educational Resources Information Center

Sonuga-Barke, Edmund J. S.; De Houwer, Jan; De Ruiter, Karen; Ajzenstzen, Michal; Holland, Sarah

2004-01-01

Background: The selective attention of children with attention deficit/hyperactivity disorder (AD/HD) to briefly exposed delay-related cues was examined in two experiments using a dot-probe conditioning paradigm. Method: Colour cues were paired with negatively (i.e., imposition of delay) and positively valenced cues (i.e., escape from or avoidance…

AD/HD and the capture of attention by briefly exposed delay-related cues: evidence from a conditioning paradigm.

PubMed

Sonuga-Barke, Edmund J S; De Houwer, Jan; De Ruiter, Karen; Ajzenstzen, Michal; Holland, Sarah

2004-02-01

The selective attention of children with attention deficit/hyperactivity disorder (AD/HD) to briefly exposed delay-related cues was examined in two experiments using a dot-probe conditioning paradigm. Colour cues were paired with negatively (i.e., imposition of delay) and positively valenced cues (i.e., escape from or avoidance of delay) during a conditioning phase. These cues were presented alongside neutral cues in a subsequent dot-probe detection phase. In experiment 1 teacher-identified children with AD/HD (N = 12), but not controls (N = 12), displayed an attentional bias towards both positively and negatively valenced cues. In experiment 2 children with a diagnosis of hyperkinetic disorder (N = 15), but not controls (N = 15), displayed a bias towards delay-related cues. However, this effect was largely carried by the response to positively valenced cues. These results confirm the dot-probe conditioning paradigm as a useful test of motivational influence on attention. They provide the first evidence of qualitative differences in the attentional style of children with AD/HD and give further support to those theories that highlight the motivational significance of delay in AD/HD.

Delayed and forgone care for families with chronic conditions in high-deductible health plans.

PubMed

Galbraith, Alison A; Soumerai, Stephen B; Ross-Degnan, Dennis; Rosenthal, Meredith B; Gay, Charlene; Lieu, Tracy A

2012-09-01

High-deductible health plans (HDHPs) are an increasingly common strategy to contain health care costs. Individuals with chronic conditions are at particular risk for increased out-of-pocket costs in HDHPs and resulting cost-related underuse of essential health care. To evaluate whether families with chronic conditions in HDHPs have higher rates of delayed or forgone care due to cost, compared with those in traditional health insurance plans. This mail and phone survey used multiple logistic regression to compare family-level rates of reporting delayed/forgone care in HDHPs vs. traditional plans. We selected families with children that had at least one member with a chronic condition. Families had employer-sponsored insurance in a Massachusetts health plan and >12 months of enrollment in an HDHP or a traditional plan. The primary outcome was report of any delayed or forgone care due to cost (acute care, emergency department visits, chronic care, checkups, or tests) for adults or children during the prior 12 months. Respondents included 208 families in HDHPs and 370 in traditional plans. Membership in an HDHP and lower income were each independently associated with higher probability of delayed/forgone care due to cost. For adult family members, the predicted probability of delayed/forgone care due to cost was higher in HDHPs than in traditional plans [40.0% vs 15.1% among families with incomes <400% of the federal poverty level (FPL) and 16.0% vs 4.8% among those with incomes ≥400% FPL]. Similar associations were observed for children. Among families with chronic conditions, reporting of delayed/forgone care due to cost is higher for both adults and children in HDHPs than in traditional plans. Families with lower incomes are also at higher risk for delayed/forgone care.

Immediate Extinction Causes a Less Durable Loss of Performance than Delayed Extinction following Either Fear or Appetitive Conditioning

ERIC Educational Resources Information Center

Woods, Amanda M.; Bouton, Mark E.

2008-01-01

Five experiments with rat subjects compared the effects of immediate and delayed extinction on the durability of extinction learning. Three experiments examined extinction of fear conditioning (using the conditioned emotional response method), and two experiments examined extinction of appetitive conditioning (using the food-cup entry method). In…

Planned Variation in Preanalytical Conditions to Evaluate Biospecimen Stability in the National Children’s Study (NCS)

PubMed Central

Mechanic, Leah; Mendez, Armando; Merrill, Lori; Rogers, John; Layton, Marnie; Todd, Deborah; Varanasi, Arti; O’Brien, Barbara; Meyer, William A.; Zhang, Ming; Schleicher, Rosemary L.; Moye, Jack

2014-01-01

BACKGROUND Preanalytical conditions encountered during collection, processing, and storage of biospecimens may influence laboratory results. The National Children’s Study (NCS) is a planned prospective cohort study of 100,000 families to examine the influence of a wide variety of exposures on child health. In developing biospecimen collection, processing, and storage procedures for the NCS, we identified several analytes of different biochemical categories for which it was unclear to what extent deviations from NCS procedures could influence measurement results. METHODS A pilot study was performed to examine effects of preanalytic sample handling conditions (delays in centrifugation, freezing delays, delays in separation from cells, additive delay, and tube type) on concentrations of eight different analytes. 2,825 measurements were made to assess 15 unique combinations of analyte and handling conditions in blood collected from 151 women of childbearing age (≥20 individuals per handling condition). RESULTS The majority of analytes were stable under the conditions evaluated. However, levels of plasma interleukin-6 and serum insulin were decreased in response to sample centrifugation delays of up to 5.5 hours post collection (P<0.0001). In addition, delays in freezing centrifuged plasma samples (comparing 24, 48 and 72 hours to immediate freezing) resulted in increased levels of adrenocorticotropic hormone (P=0.0014). CONCLUSIONS Determining stability of proposed analytes in response to preanalytical conditions and handling helps to ensure high-quality specimens for study now and in the future. The results inform development of procedures, plans for measurement of analytes, and interpretation of laboratory results. PMID:23924524

Retrieval practice improves memory in survivors of severe traumatic brain injury.

PubMed

Sumowski, James F; Coyne, Julia; Cohen, Amanda; Deluca, John

2014-02-01

To investigate whether retrieval practice (RP) improves delayed recall after short and long delays in survivors of severe traumatic brain injury (TBI) relative to massed restudy (MR) and spaced restudy (SR). 3(learning condition: MR, SR, RP)×2(delayed recall: 30min, 1wk) within-subject experiment. Nonprofit medical rehabilitation research center. Memory-impaired (<5th percentile) survivors of severe TBI (N=10). During RP, patients are quizzed on to-be-learned information shortly after it is presented, such that patients practice retrieval. MR consists of repeated restudy (ie, cramming). SR consists of restudy trials separated in time (ie, distributed learning). Forty-eight verbal paired associates (VPAs) were equally divided across 3 learning conditions (16 per condition). Delayed recall for one half of the VPAs was assessed after 30 minutes (8 per condition) and for the other half after 1 week (8 per condition). There was a large effect of learning condition after the short delay (P<.001, η(2)=.72), with much better recall of VPAs studied through RP (46.3%) relative to MR (12.5%) and SR (15.0%). This large effect of learning condition remained after the long delay (P=.001, η(2)=.56), as patients recalled 11.3% of the VPAs studied through RP, but nothing through MR (0.0%) and only 1.3% through SR. That is, RP was essentially the only learning condition to result in successful recall after 1 week, with most patients recalling at least 1 VPA. The robust effect of RP among TBI survivors with severe memory impairment engenders confidence that this strategy would work outside the laboratory to improve memory in real-life settings. Future randomized controlled trials of RP training are needed. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Immediate extinction causes a less durable loss of performance than delayed extinction following either fear or appetitive conditioning.

PubMed

Woods, Amanda M; Bouton, Mark E

2008-12-01

Five experiments with rat subjects compared the effects of immediate and delayed extinction on the durability of extinction learning. Three experiments examined extinction of fear conditioning (using the conditioned emotional response method), and two experiments examined extinction of appetitive conditioning (using the food-cup entry method). In all experiments, conditioning and extinction were accomplished in single sessions, and retention testing took place 24 h after extinction. In both fear and appetitive conditioning, immediate extinction (beginning 10 min after conditioning) caused a faster loss of responding than delayed extinction (beginning 24 h after conditioning). However, immediate extinction was less durable than delayed extinction: There was stronger spontaneous recovery during the final retention test. There was also substantial renewal of responding when the physical context was changed between immediate extinction and testing (Experiment 1). The results suggest that, in these two widely used conditioning preparations, immediate extinction does not erase or depotentiate the original learning, and instead creates a less permanent reduction in conditioned responding. Results did not support the possibility that the strong recovery after immediate extinction was due to a mismatch in the recent "context" provided by the presence or absence of a recent conditioning experience. Several other accounts are considered.

The Amygdala Is Critical for Trace, Delay, and Contextual Fear Conditioning

ERIC Educational Resources Information Center

Kochli, Daniel E.; Thompson, Elaine C.; Fricke, Elizabeth A.; Postle, Abagail F.; Quinn, Jennifer J.

2015-01-01

Numerous investigations have definitively shown amygdalar involvement in delay and contextual fear conditioning. However, much less is known about amygdala contributions to trace fear conditioning, and what little evidence exists is conflicting as noted in previous studies. This discrepancy may result from selective targeting of individual nuclei…

Elevated Acoustic Startle Responses in Humans: Relationship to Reduced Loudness Discomfort Level, but not Self-Report of Hyperacusis.

PubMed

Knudson, Inge M; Melcher, Jennifer R

2016-06-01

Increases in the acoustic startle response (ASR) of animals have been reported following experimental manipulations to induce tinnitus, an auditory disorder defined by phantom perception of sound. The increases in ASR have been proposed to signify the development of hyperacusis, a clinical condition defined by intolerance of normally tolerable sound levels. To test this proposal, the present study compared ASR amplitude to measures of sound-level tolerance (SLT) in humans, the only species in which SLT can be directly assessed. Participants had clinically normal/near-normal hearing thresholds, were free of psychotropic medications, and comprised people with tinnitus and without. ASR was measured as eyeblink-related electromyographic activity in response to a noise pulse presented at a range of levels and in two background conditions (noise and quiet). SLT was measured as loudness discomfort level (LDL), the lowest level of sound deemed uncomfortable, and via a questionnaire on the loudness of sounds in everyday life. Regardless of tinnitus status, ASR amplitude at a given stimulus level increased with decreasing LDL, but showed no relationship to SLT self-reported via the questionnaire. These relationships (or lack thereof) could not be attributed to hearing threshold, age, anxiety, or depression. The results imply that increases in ASR in the animal work signify decreases in LDL specifically and may not correspond to the development of hyperacusis as would be self-reported by a clinic patient.

Chemotherapy disrupts learning, neurogenesis and theta activity in the adult brain.

PubMed

Nokia, Miriam S; Anderson, Megan L; Shors, Tracey J

2012-12-01

Chemotherapy, especially if prolonged, disrupts attention, working memory and speed of processing in humans. Most cancer drugs that cross the blood-brain barrier also decrease adult neurogenesis. Because new neurons are generated in the hippocampus, this decrease may contribute to the deficits in working memory and related thought processes. The neurophysiological mechanisms that underlie these deficits are generally unknown. A possible mediator is hippocampal oscillatory activity within the theta range (3-12 Hz). Theta activity predicts and promotes efficient learning in healthy animals and humans. Here, we hypothesised that chemotherapy disrupts learning via decreases in hippocampal adult neurogenesis and theta activity. Temozolomide was administered to adult male Sprague-Dawley rats in a cyclic manner for several weeks. Treatment was followed by training with different types of eyeblink classical conditioning, a form of associative learning. Chemotherapy reduced both neurogenesis and endogenous theta activity, as well as disrupted learning and related theta-band responses to the conditioned stimulus. The detrimental effects of temozolomide only occurred after several weeks of treatment, and only on a task that requires the association of events across a temporal gap and not during training with temporally overlapping stimuli. Chemotherapy did not disrupt the memory for previously learned associations, a memory independent of (new neurons in) the hippocampus. In conclusion, prolonged systemic chemotherapy is associated with a decrease in hippocampal adult neurogenesis and theta activity that may explain the selective deficits in processes of learning that describe the 'chemobrain'. © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Sharp conditions for global stability of Lotka-Volterra systems with distributed delays

NASA Astrophysics Data System (ADS)

Faria, Teresa

We give a criterion for the global attractivity of a positive equilibrium of n-dimensional non-autonomous Lotka-Volterra systems with distributed delays. For a class of autonomous Lotka-Volterra systems, we show that such a criterion is sharp, in the sense that it provides necessary and sufficient conditions for the global asymptotic stability independently of the choice of the delay functions. The global attractivity of positive equilibria is established by imposing a diagonal dominance of the instantaneous negative feedback terms, and relies on auxiliary results showing the boundedness of all positive solutions. The paper improves and generalizes known results in the literature, namely by considering systems with distributed delays rather than discrete delays.

Focused attention improves working memory: implications for flexible-resource and discrete-capacity models.

PubMed

Souza, Alessandra S; Rerko, Laura; Lin, Hsuan-Yu; Oberauer, Klaus

2014-10-01

Performance in working memory (WM) tasks depends on the capacity for storing objects and on the allocation of attention to these objects. Here, we explored how capacity models need to be augmented to account for the benefit of focusing attention on the target of recall. Participants encoded six colored disks (Experiment 1) or a set of one to eight colored disks (Experiment 2) and were cued to recall the color of a target on a color wheel. In the no-delay condition, the recall-cue was presented after a 1,000-ms retention interval, and participants could report the retrieved color immediately. In the delay condition, the recall-cue was presented at the same time as in the no-delay condition, but the opportunity to report the color was delayed. During this delay, participants could focus attention exclusively on the target. Responses deviated less from the target's color in the delay than in the no-delay condition. Mixture modeling assigned this benefit to a reduction in guessing (Experiments 1 and 2) and transposition errors (Experiment 2). We tested several computational models implementing flexible or discrete capacity allocation, aiming to explain both the effect of set size, reflecting the limited capacity of WM, and the effect of delay, reflecting the role of attention to WM representations. Both models fit the data better when a spatially graded source of transposition error is added to its assumptions. The benefits of focusing attention could be explained by allocating to this object a higher proportion of the capacity to represent color.

A Comparison of Taped-Problem Interventions to Increase Math Fact Fluency: Does the Length of Time Delay Affect Student Learning Rates?

ERIC Educational Resources Information Center

Poncy, Brian C.; Jaspers, Kathryn E.; Hansmann, Paul R.; Bui, Levita; Matthew, William B.

2015-01-01

An alternating treatments design with a control condition was used to evaluate and compare the effects of two taped-problem interventions on addition fact fluency. Both taped-problem interventions were identical with the exception of the time delay between the auditory cue of the problem and the answer. One condition used a 2-s delay and the other…

Cross-commodity delay discounting of alcohol and money in alcohol users

PubMed Central

Moody, Lara N.; Tegge, Allison N.; Bickel, Warren K.

2017-01-01

Despite real-world implications, the pattern of delay discounting in alcohol users when the commodities now and later differ has not been well characterized. In this study, 60 participants on Amazon's Mechanical Turk completed the Alcohol Use Disorder Identification Test (AUDIT) to assess severity of use and completed four delay discounting tasks between hypothetical, equivalent amounts of alcohol and money available at five delays. The tasks included two cross-commodity (alcohol now-money later and money now-alcohol later) and two same-commodity (money now-money later and alcohol now-alcohol later) conditions. Delay discounting was significantly associated with clinical cutoffs of the AUDIT for both of the cross-commodity conditions but not for either of the same-commodity delay discounting tasks. The cross-commodity discounting conditions were related to severity of use wherein heavy users discounted future alcohol less and future money more. The change in direction of the discounting effect was dependent on the commodity that was distally available suggesting a distinctive pattern of discounting across commodities when comparing light and heavy alcohol users. PMID:29056767

Cross-commodity delay discounting of alcohol and money in alcohol users.

PubMed

Moody, Lara N; Tegge, Allison N; Bickel, Warren K

2017-06-01

Despite real-world implications, the pattern of delay discounting in alcohol users when the commodities now and later differ has not been well characterized. In this study, 60 participants on Amazon's Mechanical Turk completed the Alcohol Use Disorder Identification Test (AUDIT) to assess severity of use and completed four delay discounting tasks between hypothetical, equivalent amounts of alcohol and money available at five delays. The tasks included two cross-commodity (alcohol now-money later and money now-alcohol later) and two same-commodity (money now-money later and alcohol now-alcohol later) conditions. Delay discounting was significantly associated with clinical cutoffs of the AUDIT for both of the cross-commodity conditions but not for either of the same-commodity delay discounting tasks. The cross-commodity discounting conditions were related to severity of use wherein heavy users discounted future alcohol less and future money more. The change in direction of the discounting effect was dependent on the commodity that was distally available suggesting a distinctive pattern of discounting across commodities when comparing light and heavy alcohol users.

Stability of Nonlinear Systems with Unknown Time-varying Feedback Delay

NASA Astrophysics Data System (ADS)

Chunodkar, Apurva A.; Akella, Maruthi R.

2013-12-01

This paper considers the problem of stabilizing a class of nonlinear systems with unknown bounded delayed feedback wherein the time-varying delay is 1) piecewise constant 2) continuous with a bounded rate. We also consider application of these results to the stabilization of rigid-body attitude dynamics. In the first case, the time-delay in feedback is modeled specifically as a switch among an arbitrarily large set of unknown constant values with a known strict upper bound. The feedback is a linear function of the delayed states. In the case of linear systems with switched delay feedback, a new sufficiency condition for average dwell time result is presented using a complete type Lyapunov-Krasovskii (L-K) functional approach. Further, the corresponding switched system with nonlinear perturbations is proven to be exponentially stable inside a well characterized region of attraction for an appropriately chosen average dwell time. In the second case, the concept of the complete type L-K functional is extended to a class of nonlinear time-delay systems with unknown time-varying time-delay. This extension ensures stability robustness to time-delay in the control design for all values of time-delay less than the known upper bound. Model-transformation is used in order to partition the nonlinear system into a nominal linear part that is exponentially stable with a bounded perturbation. We obtain sufficient conditions which ensure exponential stability inside a region of attraction estimate. A constructive method to evaluate the sufficient conditions is presented together with comparison with the corresponding constant and piecewise constant delay. Numerical simulations are performed to illustrate the theoretical results of this paper.

Haloperidol and Rimonabant Increase Delay Discounting in Rats Fed High-Fat and Standard-Chow Diets

PubMed Central

Boomhower, Steven R.; Rasmussen, Erin B.

2016-01-01

The dopamine and endocannabinoid neurotransmitter systems have been implicated in delay discounting, a measure of impulsive choice, and obesity. The current study was designed to determine the extent to which haloperidol and rimonabant affected delay discounting in rats fed standard-chow and high-fat diets. Sprague-Dawley rats were allowed to free-feed under a high-fat diet (4.73 kcal/g) or a standard-chow diet (3.0 kcal/g) for three months. Then, operant sessions began in which rats (n = 9 standard chow; n = 10 high-fat) chose between one sucrose pellet delivered immediately vs. three sucrose pellets after a series of delays. In another condition, carrot-flavored pellets replaced sucrose pellets. After behavior stabilized, acute injections of rimonabant (0.3-10 mg/kg) and haloperidol (0.003-0.1 mg/kg) were administered i.p. before some choice sessions in both pellet conditions. Haloperidol and rimonabant increased discounting in both groups of rats by decreasing percent choice for the larger reinforcer and area-under-the-curve (AUC) values. Rats in the high-fat diet condition demonstrated increased sensitivity to haloperidol compared to chow-fed controls: haloperidol increased discounting in both dietary groups in the sucrose condition,, but only in the high-fat-fed rats in the carrot-pellet condition. These findings indicate that blocking D2 and CB1 receptors results in increased delay discounting, and that a high-fat diet may alter sensitivity to dopaminergic compounds using the delay-discounting task. PMID:25000488

EFFECT OF DELAYED AUDITORY FEEDBACK, SPEECH RATE, AND SEX ON SPEECH PRODUCTION.

PubMed

Stuart, Andrew; Kalinowski, Joseph

2015-06-01

Perturbations in Delayed Auditory Feedback (DAF) and speech rate were examined as sources of disruptions in speech between men and women. Fluent adult men (n = 16) and women (n = 16) spoke at a normal and an imposed fast rate of speech with 0, 25, 50, 100, and 200 msec. DAF. The syllable rate significantly increased when participants were instructed to speak at a fast rate, and the syllable rate decreased with increasing DAF delays. Men's speech rate was significantly faster during the fast speech rate condition with a 200 msec. DAF. Disfluencies increased with increasing DAF delay. Significantly more disfluency occurred at delays of 25 and 50 msec. at the fast rate condition, while more disfluency occurred at 100 and 200 msec. in normal rate conditions. Men and women did not display differences in the number of disfluencies. These findings demonstrate sex differences in susceptibility to perturbations in DAF and speech rate suggesting feedforward/feedback subsystems that monitor vocalizations may be different between sexes.

Determinants of choice for pigeons and humans on concurrent-chains schedules of reinforcement.

PubMed

Belke, T W; Pierce, W D; Powell, R A

1989-09-01

Concurrent-chains schedules of reinforcement were arranged for humans and pigeons. Responses of humans were reinforced with tokens exchangeable for money, and key pecks of 4 birds were reinforced with food. Variable-interval 30-s and 40-s schedules operated in the terminal links of the chains. Condition 1 exposed subjects to variable-interval 90-s and variable-interval 30-s initial links, respectively. Conditions 2 and 3 arranged equal initial-link schedules of 40 s or 120 s. Experimental conditions tested the descriptive adequacy of five equations: reinforcement density, delay reduction, modified delay reduction, matching and maximization. Results based on choice proportions and switch rates during the initial links showed that pigeons behaved in accord with delay-reduction models, whereas humans maximized overall rate of reinforcement. As discussed by Logue and associates in self-control research, different types of reinforcement may affect sensitivity to delay differentially. Pigeons' responses were reinforced with food, a reinforcer that is consumable upon presentation. Humans' responses were reinforced with money, a reinforcer exchanged for consumable reinforcers after it was earned. Reinforcers that are immediately consumed may generate high sensitivity to delay and behavior described as delay reduction. Reinforces with longer times to consumption may generate low sensitivity to delay and behavior that maximizes overall payoff.

Mild opioid deprivation increases the degree that opioid-dependent outpatients discount delayed heroin and money.

PubMed

Giordano, Louis A; Bickel, Warren K; Loewenstein, George; Jacobs, Eric A; Marsch, Lisa; Badger, Gary J

2002-09-01

A growing literature suggests that excessive temporal discounting of delayed rewards may be a contributing factor in the etiology of substance abuse problems. Little is known, however, about how drug deprivation may affect temporal discounting of delayed rewards by drug-dependent individuals. To examine the extent to which opioid deprivation affects how opioid-dependent individuals discount small, medium and large quantities of delayed heroin and money. Thirteen opioid-dependent individuals maintained on buprenorphine completed a hypothetical choice task in which they choose between a constant delayed reward amount and an immediate reward amount that was adjusted until they expressed indifference between both outcomes. The task was completed for three values of heroin and money rewards during eight sessions under conditions of opioid deprivation (four sessions) and satiation (four sessions). Across conditions, hyperbolic functions provided a good fit for the discounting data. Degree of discounting was significantly higher when subjects were opioid deprived. Consistent with previous findings, degree of discounting was higher for heroin than money and inversely related to the magnitude of the reward. Opioid deprivation increased the degree to which dependent individuals discounted delayed heroin and money. Understanding the conditions that affect how drug-dependent individuals discount delayed rewards might help us understand the myopic choices made by such individuals and help improve treatment outcomes.

Delay-dependent stability and added damping of SDOF real-time dynamic hybrid testing

NASA Astrophysics Data System (ADS)

Chi, Fudong; Wang, Jinting; Jin, Feng

2010-09-01

It is well-recognized that a transfer system response delay that reduces the test stability inevitably exists in real-time dynamic hybrid testing (RTDHT). This paper focuses on the delay-dependent stability and added damping of SDOF systems in RTDHT. The exponential delay term is transferred into a rational fraction by the Padé approximation, and the delay-dependent stability conditions and instability mechanism of SDOF RTDHT systems are investigated by the root locus technique. First, the stability conditions are discussed separately for the cases of stiffness, mass, and damping experimental substructure. The use of root locus plots shows that the added damping effect and instability mechanism for mass are different from those for stiffness. For the stiffness experimental substructure case, the instability results from the inherent mode because of an obvious negative damping effect of the delay. For the mass case, the delay introduces an equivalent positive damping into the inherent mode, and instability occurs at an added high frequency mode. Then, the compound stability condition is investigated for a general case and the results show that the mass ratio may have both upper and lower limits to remain stable. Finally, a high-emulational virtual shaking table model is built to validate the stability conclusions.

Failure to extinguish fear and genetic variability in the human cannabinoid receptor 1.

PubMed

Heitland, I; Klumpers, F; Oosting, R S; Evers, D J J; Leon Kenemans, J; Baas, J M P

2012-09-25

Failure to extinguish fear can lead to persevering anxiety and has been postulated as an important mechanism in the pathogenesis of human anxiety disorders. In animals, it is well documented that the endogenous cannabinoid system has a pivotal role in the successful extinction of fear, most importantly through the cannabinoid receptor 1. However, no human studies have reported a translation of this preclinical evidence yet. Healthy medication-free human subjects (N=150) underwent a fear conditioning and extinction procedure in a virtual reality environment. Fear potentiation of the eyeblink startle reflex was measured to assess fear-conditioned responding, and subjective fear ratings were collected. Participants were genotyped for two polymorphisms located within the promoter region (rs2180619) and the coding region (rs1049353) of cannabinoid receptor 1. As predicted from the preclinical literature, acquisition and expression of conditioned fear did not differ between genotypes. Crucially, whereas both homozygote (G/G, N=23) and heterozygote (A/G, N=68) G-allele carriers of rs2180619 displayed robust extinction of fear, extinction of fear-potentiated startle was absent in A/A homozygotes (N=51). Additionally, this resistance to extinguish fear left A/A carriers of rs2180619 with significantly higher levels of fear-potentiated startle at the end of the extinction training. No effects of rs1049353 genotype were observed regarding fear acquisition and extinction. These results suggest for the first time involvement of the human endocannabinoid system in fear extinction. Implications are that genetic variability in this system may underlie individual differences in anxiety, rendering cannabinoid receptor 1 a potential target for novel pharmacological treatments of anxiety disorders.

Stability analysis for discrete-time stochastic memristive neural networks with both leakage and probabilistic delays.

PubMed

Liu, Hongjian; Wang, Zidong; Shen, Bo; Huang, Tingwen; Alsaadi, Fuad E

2018-06-01

This paper is concerned with the globally exponential stability problem for a class of discrete-time stochastic memristive neural networks (DSMNNs) with both leakage delays as well as probabilistic time-varying delays. For the probabilistic delays, a sequence of Bernoulli distributed random variables is utilized to determine within which intervals the time-varying delays fall at certain time instant. The sector-bounded activation function is considered in the addressed DSMNN. By taking into account the state-dependent characteristics of the network parameters and choosing an appropriate Lyapunov-Krasovskii functional, some sufficient conditions are established under which the underlying DSMNN is globally exponentially stable in the mean square. The derived conditions are made dependent on both the leakage and the probabilistic delays, and are therefore less conservative than the traditional delay-independent criteria. A simulation example is given to show the effectiveness of the proposed stability criterion. Copyright © 2018 Elsevier Ltd. All rights reserved.

Stability Switches, Hopf Bifurcations, and Spatio-temporal Patterns in a Delayed Neural Model with Bidirectional Coupling

NASA Astrophysics Data System (ADS)

Song, Yongli; Zhang, Tonghua; Tadé, Moses O.

2009-12-01

The dynamical behavior of a delayed neural network with bi-directional coupling is investigated by taking the delay as the bifurcating parameter. Some parameter regions are given for conditional/absolute stability and Hopf bifurcations by using the theory of functional differential equations. As the propagation time delay in the coupling varies, stability switches for the trivial solution are found. Conditions ensuring the stability and direction of the Hopf bifurcation are determined by applying the normal form theory and the center manifold theorem. We also discuss the spatio-temporal patterns of bifurcating periodic oscillations by using the symmetric bifurcation theory of delay differential equations combined with representation theory of Lie groups. In particular, we obtain that the spatio-temporal patterns of bifurcating periodic oscillations will alternate according to the change of the propagation time delay in the coupling, i.e., different ranges of delays correspond to different patterns of neural activities. Numerical simulations are given to illustrate the obtained results and show the existence of bursts in some interval of the time for large enough delay.

The influence of chronic conditions and the environment on pubertal development. An example from medieval England.

PubMed

Lewis, M E; Shapland, F; Watts, R

2016-03-01

Adolescence is a unique period in human development encompassing sexual maturation (puberty) and the physical and psychological transition into adulthood. It is a crucial time for healthy development and any adverse environmental conditions, poor nutrition, or chronic infection can alter the timing of these physical changes; delaying menarche in girls or the age of peak height velocity in boys. This study explores the impact of chronic illness on the tempo of puberty in 607 adolescent skeletons from medieval England (AD 900-1550). A total of 135 (22.2%) adolescents showed some delay in their pubertal development, and this lag increased with age. Of those with a chronic condition, 40.0% (n=24/60) showed delay compared to only 20.3% (n=111/547) of the non-pathology group. This difference was statistically significant. A binary logistic regression model demonstrated a significant association between increasing delay in pubertal stage attainment with age in the pathology group. This is the first time that chronic conditions have been directly associated with a delay in maturation in the osteological record, using a new method to assess stages of puberty in skeletal remains. Copyright © 2015 Elsevier Inc. All rights reserved.

Systemic delay propagation in the US airport network

PubMed Central

Fleurquin, Pablo; Ramasco, José J.; Eguiluz, Victor M.

2013-01-01

Technologically driven transport systems are characterized by a networked structure connecting operation centers and by a dynamics ruled by pre-established schedules. Schedules impose serious constraints on the timing of the operations, condition the allocation of resources and define a baseline to assess system performance. Here we study the performance of an air transportation system in terms of delays. Technical, operational or meteorological issues affecting some flights give rise to primary delays. When operations continue, such delays can propagate, magnify and eventually involve a significant part of the network. We define metrics able to quantify the level of network congestion and introduce a model that reproduces the delay propagation patterns observed in the U.S. performance data. Our results indicate that there is a non-negligible risk of systemic instability even under normal operating conditions. We also identify passenger and crew connectivity as the most relevant internal factor contributing to delay spreading. PMID:23362459

Dissipativity and stability analysis of fractional-order complex-valued neural networks with time delay.

PubMed

Velmurugan, G; Rakkiyappan, R; Vembarasan, V; Cao, Jinde; Alsaedi, Ahmed

2017-02-01

As we know, the notion of dissipativity is an important dynamical property of neural networks. Thus, the analysis of dissipativity of neural networks with time delay is becoming more and more important in the research field. In this paper, the authors establish a class of fractional-order complex-valued neural networks (FCVNNs) with time delay, and intensively study the problem of dissipativity, as well as global asymptotic stability of the considered FCVNNs with time delay. Based on the fractional Halanay inequality and suitable Lyapunov functions, some new sufficient conditions are obtained that guarantee the dissipativity of FCVNNs with time delay. Moreover, some sufficient conditions are derived in order to ensure the global asymptotic stability of the addressed FCVNNs with time delay. Finally, two numerical simulations are posed to ensure that the attention of our main results are valuable. Copyright © 2016 Elsevier Ltd. All rights reserved.

Global asymptotic stability of hybrid bidirectional associative memory neural networks with time delays

NASA Astrophysics Data System (ADS)

Arik, Sabri

2006-02-01

This Letter presents a sufficient condition for the existence, uniqueness and global asymptotic stability of the equilibrium point for bidirectional associative memory (BAM) neural networks with distributed time delays. The results impose constraint conditions on the network parameters of neural system independently of the delay parameter, and they are applicable to all bounded continuous non-monotonic neuron activation functions. The results are also compared with the previous results derived in the literature.

Eliminating the Attentional Blink through Binaural Beats: A Case for Tailored Cognitive Enhancement.

PubMed

Reedijk, Susan A; Bolders, Anne; Colzato, Lorenza S; Hommel, Bernhard

2015-01-01

Enhancing human cognitive performance is a topic that continues to spark scientific interest. Studies into cognitive-enhancement techniques often fail to take inter-individual differences into account, however, which leads to underestimation of the effectiveness of these techniques. The current study investigated the effect of binaural beats, a cognitive-enhancement technique, on attentional control in an attentional blink (AB) task. As predicted from a neurocognitive approach to cognitive control, high-frequency binaural beats eliminated the AB, but only in individuals with low spontaneous eye-blink rates (indicating low striatal dopamine levels). This suggests that the way in which cognitive-enhancement techniques, such as binaural beats, affect cognitive performance depends on inter-individual differences.

Differentiation of Speech Delay and Global Developmental Delay in Children Using DTI Tractography-Based Connectome.

PubMed

Jeong, J-W; Sundaram, S; Behen, M E; Chugani, H T

2016-06-01

Pure speech delay is a common developmental disorder which, according to some estimates, affects 5%-8% of the population. Speech delay may not only be an isolated condition but also can be part of a broader condition such as global developmental delay. The present study investigated whether diffusion tensor imaging tractography-based connectome can differentiate global developmental delay from speech delay in young children. Twelve children with pure speech delay (39.1 ± 20.9 months of age, 9 boys), 14 children with global developmental delay (39.3 ± 18.2 months of age, 12 boys), and 10 children with typical development (38.5 ± 20.5 months of age, 7 boys) underwent 3T DTI. For each subject, whole-brain connectome analysis was performed by using 116 cortical ROIs. The following network metrics were measured at individual regions: strength (number of the shortest paths), efficiency (measures of global and local integration), cluster coefficient (a measure of local aggregation), and betweeness (a measure of centrality). Compared with typical development, global and local efficiency were significantly reduced in both global developmental delay and speech delay (P < .0001). The nodal strength of the cognitive network is reduced in global developmental delay, whereas the nodal strength of the language network is reduced in speech delay. This finding resulted in a high accuracy of >83% ± 4% to discriminate global developmental delay from speech delay. The network abnormalities identified in the present study may underlie the neurocognitive and behavioral consequences commonly identified in children with global developmental delay and speech delay. Further validation studies in larger samples are required. © 2016 by American Journal of Neuroradiology.

Facilitation of listening comprehension by visual information under noisy listening condition

NASA Astrophysics Data System (ADS)

Kashimada, Chiho; Ito, Takumi; Ogita, Kazuki; Hasegawa, Hiroshi; Kamata, Kazuo; Ayama, Miyoshi

2009-02-01

Comprehension of a sentence under a wide range of delay conditions between auditory and visual stimuli was measured in the environment with low auditory clarity of the level of -10dB and -15dB pink noise. Results showed that the image was helpful for comprehension of the noise-obscured voice stimulus when the delay between the auditory and visual stimuli was 4 frames (=132msec) or less, the image was not helpful for comprehension when the delay between the auditory and visual stimulus was 8 frames (=264msec) or more, and in some cases of the largest delay (32 frames), the video image interfered with comprehension.

A learning assessment procedure to re-evaluate three persons with a diagnosis of post-coma vegetative state and pervasive motor impairment.

PubMed

Lancioni, Giulio E; Singh, Nirbhay N; O'Reilly, Mark F; Sigafoos, Jeff; de Tommaso, Marina; Megna, Gianfranco; Bosco, Andrea; Buonocunto, Francesca; Sacco, Valentina; Chiapparino, Claudia

2009-02-01

Detecting signs of learning in persons with a diagnosis of post-coma vegetative state and profound motor disabilities could modify their diagnostic label and provide new hopes. In this study, three adults with such a diagnosis were exposed to learning assessment to search for those signs. PROCEDURE AND DESIGN: The assessment procedure relied on participants' eye-blinking responses and microswitch-based technology. The technology consisted of an electronically regulated optic microswitch mounted on an eyeglasses' frame that the participants wore during the study and an electronic control system connected to stimulus sources. Each participant followed an ABABCB design, in which A represented baseline periods, B intervention periods with stimuli contingent on the responses and C a control condition with stimuli presented non-contingently. The level of responding during the B phases was significantly higher than the levels observed during the A phases as well as the C phase for all participants (i.e. indicating clear signs of learning by them). These findings may have important implications for (a) changing the participants' diagnostic label and offering them new programme opportunities and (b) including learning assessment within the evaluation package used for persons with post-coma profound multiple disabilities.

Voluntary emotion regulation in anorexia nervosa: A preliminary emotion-modulated startle investigation.

PubMed

Racine, Sarah E; Forbush, Kelsie T; Wildes, Jennifer E; Hagan, Kelsey E; Pollack, Lauren O; May, Casey

2016-06-01

Emotion regulation difficulties are implicated in the development and maintenance of anorexia nervosa (AN). However, research has been limited by an almost exclusive reliance on self-report. This study is the first to use the emotion-modulated startle paradigm (EMSP) to investigate emotional reactivity and voluntary emotion regulation in individuals with AN. Twenty women with AN viewed negative, positive, neutral, and food images and were asked to enhance, suppress, or maintain their emotional responses mid-way through picture presentation. Startle eyeblink magnitudes in response to startle probes administered prior, and subsequent, to regulation instructions indexed emotional reactivity and regulation, respectively. On emotional reactivity trials, startle magnitudes were greater for negative, positive, and food images, compared to neutral images. Participants had difficulty suppressing startle responses to negative and food images, as indicated by non-significant suppress-maintain comparisons. In contrast, startle responses to enhance and suppress cues during presentation of pleasant images were comparable and significantly lower than maintain cues. Findings converge with self-report data to suggest that patients with AN have difficulties with voluntary emotion regulation. The EMSP may be a promising trans-diagnostic method for examining emotion regulation difficulties that underlie risk for eating disorders and other psychiatric conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cerebrotendinous xanthomatosis (CTX): an association of pulverulent cataracts and pseudo-dominant developmental delay in a family with a splice site mutation in CYP27A1--a case report.

PubMed

Bourkiza, Rabia; Joyce, Sarah; Patel, Himanshu; Chan, Michelle; Meyer, Esther; Maher, Eamonn R; Reddy, M Ashwin

2010-06-01

A 15-year-old boy with developmental delay presented to the pediatric ophthalmology clinic with bilateral pulverulent cataracts. The family was examined for developmental delay, cataracts and systemic problems. The parents were consanguineous and originally from Bangladesh. All the children were born in the UK. The mother and 5 children had developmental delay. Three children had global developmental delay, diarrhea and pulverulent cataracts. Two children had microcephaly, developmental delay, constipation and no cataracts. The mother did not have microcephaly, cataracts or gastrointestinal problems. Linkage analysis via autozygosity testing was performed for detection of loci and candidate genes. The patients with cataracts were segregated with homozygous mutations in the CYP27A1 (G to A substitution at position +1 of intron 6). The complex nature of this family's findings suggested that it had an unusual autosomal dominant condition with variable expression. Autozygosity testing demonstrated that three members had Cerebrotendinous xanthomatosis (CTX), which is inherited in an autosomal recessive manner. The aetiology of the developmental delay in other family members remains unknown. Cerebrotendinous xanthomatosis is a rare autosomal recessive condition that can result in neurological deficits and early death if left untreated. In view of the reversible nature of the condition with appropriate treatment, there needs to be a high level of suspicion of CTX for any child with cataracts and developmental delay even if the pattern of inheritance is not straightforward at initial assessment.

Synchronization of Reaction-Diffusion Neural Networks With Dirichlet Boundary Conditions and Infinite Delays.

PubMed

Sheng, Yin; Zhang, Hao; Zeng, Zhigang

2017-10-01

This paper is concerned with synchronization for a class of reaction-diffusion neural networks with Dirichlet boundary conditions and infinite discrete time-varying delays. By utilizing theories of partial differential equations, Green's formula, inequality techniques, and the concept of comparison, algebraic criteria are presented to guarantee master-slave synchronization of the underlying reaction-diffusion neural networks via a designed controller. Additionally, sufficient conditions on exponential synchronization of reaction-diffusion neural networks with finite time-varying delays are established. The proposed criteria herein enhance and generalize some published ones. Three numerical examples are presented to substantiate the validity and merits of the obtained theoretical results.

Global robust stability of bidirectional associative memory neural networks with multiple time delays.

PubMed

Senan, Sibel; Arik, Sabri

2007-10-01

This correspondence presents a sufficient condition for the existence, uniqueness, and global robust asymptotic stability of the equilibrium point for bidirectional associative memory neural networks with discrete time delays. The results impose constraint conditions on the network parameters of the neural system independently of the delay parameter, and they are applicable to all bounded continuous nonmonotonic neuron activation functions. Some numerical examples are given to compare our results with the previous robust stability results derived in the literature.

Predictors of healthcare seeking delays among children with chronic musculoskeletal disorders in Nepal.

PubMed

LeBrun, Drake G; Talwar, Divya; Pham, Tuyetnhi A; Banskota, Bibek; Spiegel, David A

2017-12-01

Healthcare seeking behaviors among children with musculoskeletal disorders are poorly understood. We sought to analyze healthcare seeking delays among children with chronic musculoskeletal conditions in Nepal and identify predictors of clinically significant delays. A cross-sectional study was conducted at a large pediatric musculoskeletal rehabilitation center in Nepal. Baseline sociodemographic data and healthcare seeking behaviors were assessed via interviews with 75 randomly selected caregivers. Delays of at least 3 months between disease recognition and presentation to a health worker were considered clinically significant. Predictors of significant delay were assessed via multivariable logistic regression. Clubfoot was the most common condition seen in the study sample (N = 33; 37%). Mean and median presentation delays were 33 months and 14 months, respectively. Sixty-seven percent of children were delayed at least 3 months and 40% were delayed at least 2 years. Caregiver occupation in agriculture or unskilled labor was associated with an increased risk of delayed presentation (adjusted OR = 4.05; 95% CI: 1.36-12.09). Children with chronic musculoskeletal disorders in Nepal face significant delays in accessing healthcare. This poses a major clinical problem as the delayed diagnosis and treatment of childhood musculoskeletal disorders can complicate management options and decrease long-term quality of life. Copyright © 2017 Ministry of Health, Saudi Arabia. Published by Elsevier Ltd. All rights reserved.

Acquisition of delayed matching in the pigeon.

PubMed

Berryman, R; Cumming, W W; Nevin, J A

1963-01-01

Pigeons were exposed to three successive matching-to-sample procedures. On a given trial, the sample (red, green or blue light) appeared on a center key; observing responses to this key produced the comparison stimuli on two side keys. Seven different experimental conditions could govern the temporal relations between the sample and comparison stimuli. In the "simultaneous" condition, the center key response was followed immediately by illumination of the side key comparison stimuli, with the center key remaining on. In "zero delay" the center key response simultaneously turned the side keys on and the center key off, while in the "variable delay" conditions, intervals of 1, 2, 4, 10, and 24 sec were interposed between the offset of the sample and the appearance of the comparison stimuli on the side keys. In all conditions, a response to the side key of matching hue produced reinforcement, while a response to the non-matching side key was followed by a blackout. In procedure I all seven experimental conditions were presented in randomly permutated order. After nine sessions of exposure (at 191 trials per session, for a total of 1719 trials) the birds gave no evidence of acquisition in any of the conditions. They were therefore transferred to Procedure II, which required them to match only in the "simultaneous" condition, with both the sample and comparison stimuli present at the same time. With the exception of one bird, all subjects acquired this performance to near 100% levels. Next, in Procedure III, they were once more exposed to presentation of all seven experimental conditions in random order. In contrast to Procedure I, they now acquired the delay performance, and were able to match effectively at delays of about 4 sec.

Passivity of memristive BAM neural networks with leakage and additive time-varying delays

NASA Astrophysics Data System (ADS)

Wang, Weiping; Wang, Meiqi; Luo, Xiong; Li, Lixiang; Zhao, Wenbing; Liu, Linlin; Ping, Yuan

2018-02-01

This paper investigates the passivity of memristive bidirectional associate memory neural networks (MBAMNNs) with leakage and additive time-varying delays. Based on some useful inequalities and appropriate Lyapunov-Krasovskii functionals (LKFs), several delay-dependent conditions for passivity performance are obtained in linear matrix inequalities (LMIs). Moreover, the leakage delays as well as additive delays are considered separately. Finally, numerical simulations are provided to demonstrate the feasibility of the theoretical results.

The WS transform for the Kuramoto model with distributed amplitudes, phase lag and time delay

NASA Astrophysics Data System (ADS)

Lohe, M. A.

2017-12-01

We apply the Watanabe-Strogatz (WS) transform to a generalized Kuramoto model with distributed parameters describing the amplitude of oscillation, phase lag, and time delay at each node of the system. The model has global coupling and identical frequencies, but allows for repulsive interactions at arbitrary nodes leading to conformist-contrarian phenomena together with variable amplitude and time-delay effects. We show how to determine the initial values of the WS system for any initial conditions for the Kuramoto system, and investigate the asymptotic behaviour of the WS variables. For the case of zero time delay the possible asymptotic configurations are determined by the sign of a single parameter μ which measures whether or not the attractive nodes dominate the repulsive nodes. If μ>0 the system completely synchronizes from general initial conditions, whereas if μ<0 one of two types of phase-locked synchronization occurs, depending on the initial values, while for μ=0 periodic solutions can occur. For the case of arbitrary non-uniform time delays we derive a stability condition for completely synchronized solutions.

Stability and chaotification of vibration isolation floating raft systems with time-delayed feedback control.

PubMed

Li, Y L; Xu, D L; Fu, Y M; Zhou, J X

2011-09-01

This paper presents a systematic study on the stability of a two-dimensional vibration isolation floating raft system with a time-delayed feedback control. Based on the generalized Sturm criterion, the critical control gain for the delay-independent stability region and critical time delays for the stability switches are derived. The critical conditions can provide a theoretical guidance of chaotification design for line spectra reduction. Numerical simulations verify the correctness of the approach. Bifurcation analyses reveal that chaotification is more likely to occur in unstable region defined by these critical conditions, and the stiffness of the floating raft and mass ratio are the sensitive parameters to reduce critical control gain.

Assessment Regarding Impact of Atmospheric Conditions on Space Shuttle Launch Delays

NASA Technical Reports Server (NTRS)

Johnson D. L.; Pearson, S. D.; Vaughan, W. W.; Batts, G. W.

1998-01-01

The atmospheric environment definition has played a key role in the development and operation of the NASA Space Shuttle as it has in other NASA Space Vehicle Programs. The objective of any definition of natural environment design requirements for a space vehicle development is to insure that the vehicle will perform safely and in a timely manner relative to the mission(s) for which the vehicle is being developed. The NASA Space Shuttle has enjoyed the longest tenure of any Space Vehicle from an operational standpoint. As such, it has provided a wealth of information on many engineering aspects of a Space Vehicle plus the influence of the atmosphere on operational endeavors. The atmospheric environment associated with the NASA Space Shuttle launches at the NASA Kennedy Space Center in Florida has been reviewed and studied over the entire NASA Space Shuttle flight history. The results of the analysis of atmospheric environment related launch delays relative to other sources of launch delays has been assessed. This paper will provide a summary of those conditions as well as mission analysis examples focused on atmospheric constraints for launch. Atmospheric conditions associated with NASA Space Shuttle launch delays will be presented to provide a reference as to the type conditions experienced which have mainly caused the delays.

Chronic stress and sex differences on the recall of fear conditioning and extinction.

PubMed

Baran, Sarah E; Armstrong, Charles E; Niren, Danielle C; Hanna, Jeffery J; Conrad, Cheryl D

2009-03-01

Chronic stress effects and sex differences were examined on conditioned fear extinction. Male and female Sprague-Dawley rats were chronically stressed by restraint (6 h/d/21 d), conditioned to tone and footshock, followed by extinction after 1 h and 24 h delays. Chronic stress impaired the recall of fear extinction in males, as evidenced by high freezing to tone after the 24 h delay despite exposure to the previous 1 h delay extinction trials, and this effect was not due to ceiling effects from overtraining during conditioning. In contrast, chronic stress attenuated the recall of fear conditioning acquisition in females, regardless of exposure to the 1 h extinction exposure. Since freezing to tone was reinstated following unsignalled footshocks, the deficit in the stressed rats reflected impaired recall rather than impaired consolidation. Sex differences in fear conditioning and extinction were observed in nonstressed controls as well, with control females resisting extinction to tone. Analysis of contextual freezing showed that all groups (control, stress, male, female) increased freezing immediately after the first tone extinction trial, demonstrating contextual discrimination. These findings show that chronic stress and sex interact to influence fear conditioning, with chronic stress impairing the recall of delayed fear extinction in males to implicate the medial prefrontal cortex, disrupting the recall of the fear conditioning acquisition in females to implicate the amygdala, and nonstressed controls exhibiting sex differences in fear conditioning and extinction, which may involve the amygdala and/or corticosterone levels.

The influence of performance on action-effect integration in sense of agency.

PubMed

Wen, Wen; Yamashita, Atsushi; Asama, Hajime

2017-08-01

Sense of agency refers to the subjective feeling of being able to control an outcome through one's own actions or will. Prior studies have shown that both sensory processing (e.g., comparisons between sensory feedbacks and predictions basing on one's motor intentions) and high-level cognitive/constructive processes (e.g., inferences based on one's performance or the consequences of one's actions) contribute to judgments of sense of agency. However, it remains unclear how these two types of processes interact, which is important for clarifying the mechanisms underlying sense of agency. Thus, we examined whether performance-based inferences influence action-effect integration in sense of agency using a delay detection paradigm in two experiments. In both experiments, participants pressed left and right arrow keys to control the direction in which a moving dot was travelling. The dot's response delay was manipulated randomly on 7 levels (0-480ms) between the trials; for each trial, participants were asked to judge whether the dot response was delayed and to rate their level of agency over the dot. In Experiment 1, participants tried to direct the dot to reach a destination on the screen as quickly as possible. Furthermore, the computer assisted participants by ignoring erroneous commands for half of the trials (assisted condition), while in the other half, all of the participants' commands were executed (self-control condition). In Experiment 2, participants directed the dot as they pleased (without a specific goal), but, in half of the trials, the computer randomly ignored 32% of their commands (disturbed condition) rather than assisted them. The results from the two experiments showed that performance enhanced action-effect integration. Specifically, when task performance was improved through the computer's assistance in Experiment 1, delay detection was reduced in the 480-ms delay condition, despite the fact that 32% of participants' commands were ignored. Conversely, when no feedback on task performance was given (as in Experiment 2), the participants reported greater delay when some of their commands were randomly ignored. Furthermore, the results of a logistic regression analysis showed that the threshold of delay detection was greater in the assisted condition than in the self-control condition in Experiment 1, which suggests a wider time window for action-effect integration. A multivariate analysis also revealed that assistance was related to reduced delay detection via task performance, while reduced delay detection was directly correlated with a better sense of agency. These results indicate an association between the implicit and explicit aspects of sense of agency. Copyright © 2017 Elsevier Inc. All rights reserved.

Hatch plasticity in response to varied inundation frequency in Aedes albopictus.

PubMed

Vitek, Christopher J; Livdahl, Todd

2009-07-01

Eggs of container-breeding mosquitoes are able to withstand drought conditions as an egg and hatch when submerged. Frequent rainfall can be simulated by frequent submersion, and drought conditions can be simulated by infrequent submersion. We examined the hatch response of Aedes albopictus (Skuse) eggs to simulated drought conditions. Ae. albopictus eggs from a strain originating outside Kobe, Japan, were subjected to one of three treatments; high-frequency hatch stimulation consisting of submerging the eggs in a nutrient broth mixture every 3 d, low-frequency hatch stimulation consisting of submerging the eggs every 7 d, and delayed high-frequency hatch stimulation. Eggs that were subjected to lower-frequency stimulation showed a significant decrease in hatch delay, which was the opposite of the predicted response. This decrease in hatch delay may be an example of hatch plasticity in response to drought conditions. This response could not be explained as a result of the difference in the ages of the eggs on any given stimulus. A decreased hatch delay response to potential drought conditions combined with rapid larval development may enable Ae. albopictus, whose eggs are not as desiccation resistant as some other container-breeding mosquitoes, to survive extended drought.

Muscle segment homeobox genes direct embryonic diapause by limiting inflammation in the uterus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cha, Jeeyeon; Burnum-Johnson, Kristin E.; Bartos, Amanda

Embryonic diapause (delayed implantation) is a reproductive strategy widespread in the animal kingdom. Under this condition, embryos at the blastocyst stage become dormant simultaneously with uterine quiescence until environmental or physiological conditions are favorable for the survival of the mother and newborn. Under favorable conditions, activation of the blastocyst and uterus ensues with implantation and progression of pregnancy. Although endocrine factors are known to participate in this process, the underlying molecular mechanism coordinating this phenomenon is not clearly understood. We recently found that uterine muscle segment homeobox (Msx) transcription factors are critical for the initiation and maintenance of delayed implantationmore » in mice. To better understand why Msx genes are critical for delayed implantation, we compared uterine proteomics profiles between littermate floxed (Msx1/Msx2f/f) mice and mice with uterine deletion of Msx genes (Msx1/Msx2d/d) under delayed conditions. In Msx1/Msx2d/d uteri, pathways including protein translation, ubiquitin-proteasome system, inflammation, chaperone-mediated protein folding, and endoplasmic reticulum (ER) stress were enriched, and computational modeling showed intersection of these pathways on inflammatory responses. Indeed, increases in the ubiquitin-proteasome system and inflammation conformed to proteotoxic and ER stress in Msx1/Msx2d/d uteri under delayed conditions. Interestingly, treatment with a proteasome inhibitor bortezomib further exacerbated ER stress in Msx1/Msx2d/d uteri with aggravated inflammatory response, deteriorating rate of blastocyst recovery and failure to sustain delayed implantation. This study highlights a previously unrecognized role for Msx in preventing proteotoxic stress and inflammatory responses to coordinate embryo dormancy and uterine quiescence during embryonic diapause.« less

Defensive mobilization in specific phobia: Fear specificity, negative affectivity and diagnostic prominence

PubMed Central

McTeague, Lisa M.; Lang, Peter J.; Wangelin, Bethany C.; Laplante, Marie-Claude; Bradley, Margaret M.

2012-01-01

Background Understanding of exaggerated responsivity in specific phobia—its physiology and neural mediators—has advanced considerably. However, despite strong phenotypic evidence that prominence of specific phobia relative to co-occurring conditions (i.e., principal versus non-principal disorder) is associated with dramatic differences in subjective distress, there is yet no consideration of such comorbidity issues on objective defensive reactivity. Methods A community sample of specific phobia (N=74 principal phobia; N=86 non-principal phobia) and control (n=76) participants imagined threatening and neutral events while acoustic startle probes were presented and eye-blink responses (orbicularis occuli) recorded. Changes in heart rate, skin conductance level, and facial expressivity were also measured. Results Principal specific phobia patients far exceeded controls in startle reflex and autonomic reactivity during imagery of idiographic fear scenes. Distinguishing between single and multiple phobias within principal phobia and comparing these to non-principal phobia revealed a continuum of decreasing defensive mobilization: single phobia patients were strongly reactive, multiple phobia intermediate, and non-principal patients reliably attenuated—the inverse of measures of pervasive anxiety and dysphoria (i.e., negative affectivity). Further, as more disorders supplanted specific phobia from principal disorder, overall defensive mobilization was systematically more impaired. Conclusions The exaggerated responsivity considered characteristic of specific phobia is limited to those patients for whom circumscribed fear is the most impairing condition, and coincident with little additional affective psychopathology. As specific phobia is superseded in severity by broad and chronic negative affectivity, defensive reactivity progressively diminishes. Focal fears may still be clinically-significant, but not reflected in objective measures of defensive mobilization. PMID:22386377

Defensive mobilization in specific phobia: fear specificity, negative affectivity, and diagnostic prominence.

PubMed

McTeague, Lisa M; Lang, Peter J; Wangelin, Bethany C; Laplante, Marie-Claude; Bradley, Margaret M

2012-07-01

Understanding of exaggerated responsivity in specific phobia-its physiology and neural mediators-has advanced considerably. However, despite strong phenotypic evidence that prominence of specific phobia relative to co-occurring conditions (i.e., principal versus nonprincipal disorder) is associated with dramatic differences in subjective distress, there is yet no consideration of such comorbidity issues on objective defensive reactivity. A community sample of specific phobia (n = 74 principal; n = 86 nonprincipal) and control (n = 76) participants imagined threatening and neutral events while acoustic startle probes were presented and eyeblinks (orbicularis occuli) recorded. Changes in heart rate, skin conductance level, and facial expressivity were also measured. Principal specific phobia patients far exceeded control participants in startle reflex and autonomic reactivity during idiographic fear imagery. Distinguishing between single and multiple phobias within principal phobia and comparing these with nonprincipal phobia revealed a continuum of decreasing defensive mobilization: single patients were strongly reactive, multiple patients were intermediate, and nonprincipal patients were attenuated-the inverse of measures of pervasive anxiety and dysphoria (i.e., negative affectivity). Further, as more disorders supplanted specific phobia from principal disorder, overall defensive mobilization was systematically more impaired. The exaggerated responsivity characteristic of specific phobia is limited to those patients for whom circumscribed fear is the most impairing condition and coincident with little additional affective psychopathology. As specific phobia is superseded in severity by broad and chronic negative affectivity, defensive reactivity progressively diminishes. Focal fears may still be clinically significant but not reflected in objective defensive mobilization. Copyright © 2012 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Relationship between Weather, Traffic and Delay Based on Empirical Methods

NASA Technical Reports Server (NTRS)

Sridhar, Banavar; Swei, Sean S. M.

2006-01-01

The steady rise in demand for air transportation over the years has put much emphasis on the need for sophisticated air traffic flow management (TFM) within the National Airspace System (NAS). The NAS refers to hardware, software and people, including runways, radars, networks, FAA, airlines, etc., involved in air traffic management (ATM) in the US. One of the metrics that has been used to assess the performance of NAS is the actual delays provided through FAA's Air Traffic Operations Network (OPSNET). The OPSNET delay data includes those reportable delays, i.e. delays of 15 minutes or more experienced by Instrument Flight Rule (IFR) flights, submitted by the FAA facilities. These OPSNET delays are caused by the application of TFM initiatives in response to, for instance, weather conditions, increased traffic volume, equipment outages, airline operations, and runway conditions. TFM initiatives such as, ground stops, ground delay programs, rerouting, airborne holding, and miles-in-trail restrictions, are actions which are needed to control the air traffic demand to mitigate the demand-capacity imbalance due to the reduction in capacity. Consequently, TFM initiatives result in NAS delays. Of all the causes, weather has been identified as the most important causal factor for NAS delays. Therefore, in order to accurately assess the NAS performance, it has become necessary to create a baseline for NAS performance and establish a model which characterizes the relation between weather and NAS delays.

Piloted simulator study of allowable time delay in pitch flight control system of a transport airplane with negative static stability

NASA Technical Reports Server (NTRS)

Grantham, William D.; Smith, Paul M.; Person, Lee H., Jr.; Meyer, Robert T.; Tingas, Stephen A.

1987-01-01

A piloted simulation study was conducted to determine the permissible time delay in the flight control system of a 10-percent statically unstable transport airplane during cruise flight conditions. The math model used for the simulation was a derivative Lockheed L-1011 wide-body jet transport. Data were collected and analyzed from a total of 137 cruising flights in both calm- and turbulent-air conditions. Results of this piloted simulation study verify previous findings that show present military specifications for allowable control-system time delay may be too stringent when applied to transport-size airplanes. Also, the degree of handling-qualities degradation due to time delay is shown to be strongly dependent on the source of the time delay in an advanced flight control system. Maximum allowable time delay for each source of time delay in the control system, in addition to a less stringent overall maximum level of time delay, should be considered for large aircraft. Preliminary results also suggest that adverse effects of control-system time delay may be at least partially offset by variations in control gearing. It is recommended that the data base include different airplane baselines, control systems, and piloting tasks with many pilots participating, so that a reasonable set of limits for control-system time delay can be established to replace the military specification limits currently being used.

Acquisition of control skill with delayed and compensated displays.

PubMed

Ricard, G L

1995-09-01

The difficulty of mastering a two-axis, compensatory, manual control task was manipulated by introducing transport delays into the feedback loop of the controlled element. Realistic aircraft dynamics were used. Subjects' display was a simulation of an "inside-out" artificial horizon instrument perturbed by atmospheric turbulence. The task was to maintain straight and level flight, and delays tested were representative of those found in current training simulators. Delay compensations in the form of first-order lead and first-order lead/lag transfer functions, along with an uncompensated condition, were factorially combined with added delays. Subjects were required to meet a relatively strict criterion for performance. Control activity showed no differences during criterion performance, but the trials needed to achieve the criterion were linearly related to the magnitude of the delay and the compensation condition. These data were collected in the context of aircraft attitude control, but the results can be applied to the simulation of other vehicles, to remote manipulation, and to maneuvering in graphical environments.

The role of the medial prefrontal cortex in trace fear extinction

PubMed Central

Kwapis, Janine L.; Jarome, Timothy J.

2015-01-01

The extinction of delay fear conditioning relies on a neural circuit that has received much attention and is relatively well defined. Whether this established circuit also supports the extinction of more complex associations, however, is unclear. Trace fear conditioning is a better model of complex relational learning, yet the circuit that supports extinction of this memory has received very little attention. Recent research has indicated that trace fear extinction requires a different neural circuit than delay extinction; trace extinction requires the participation of the retrosplenial cortex, but not the amygdala, as noted in a previous study. Here, we tested the roles of the prelimbic and infralimbic regions of the medial prefrontal cortex in trace and delay fear extinction by blocking NMDA receptors during extinction learning. We found that the prelimbic cortex is necessary for trace, but not for delay fear extinction, whereas the infralimbic cortex is involved in both types of extinction. These results are consistent with the idea that trace fear associations require plasticity in multiple cortical areas for successful extinction. Further, the infralimbic cortex appears to play a role in extinction regardless of whether the animal was initially trained in trace or delay conditioning. Together, our results provide new information about how the neural circuits supporting trace and delay fear extinction differ. PMID:25512576

Two-stage AMPA receptor trafficking in classical conditioning and selective role for glutamate receptor subunit 4 (tGluA4) flop splice variant

PubMed Central

Zheng, Zhaoqing; Sabirzhanov, Boris

2012-01-01

Previously, we proposed a two-stage model for an in vitro neural correlate of eyeblink classical conditioning involving the initial synaptic incorporation of glutamate receptor A1 (GluA1)-containing α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid type receptors (AMPARs) followed by delivery of GluA4-containing AMPARs that support acquisition of conditioned responses. To test specific elements of our model for conditioning, selective knockdown of GluA4 AMPAR subunits was used using small-interfering RNAs (siRNAs). Recently, we sequenced and characterized the GluA4 subunit and its splice variants from pond turtles, Trachemys scripta elegans (tGluA4). Analysis of the relative abundance of mRNA expression by real-time RT-PCR showed that the flip/flop variants of tGluA4, tGluA4c, and a novel truncated variant tGluA4trc1 are major isoforms in the turtle brain. Here, transfection of in vitro brain stem preparations with anti-tGluA4 siRNA suppressed conditioning, tGluA4 mRNA and protein expression, and synaptic delivery of tGluA4-containing AMPARs but not tGluA1 subunits. Significantly, transfection of abducens motor neurons by nerve injections of tGluA4 flop rescue plasmid prior to anti-tGluA4 siRNA application restored conditioning and synaptic incorporation of tGluA4-containing AMPARs. In contrast, treatment with rescue plasmids for tGluA4 flip or tGluA4trc1 failed to rescue conditioning. Finally, treatment with a siRNA directed against GluA1 subunits inhibited conditioning and synaptic delivery of tGluA1-containing AMPARs and importantly, those containing tGluA4. These data strongly support our two-stage model of conditioning and our hypothesis that synaptic incorporation of tGluA4-containing AMPARs underlies the acquisition of in vitro classical conditioning. Furthermore, they suggest that tGluA4 flop may have a critical role in conditioning mechanisms compared with the other tGluA4 splice variants. PMID:22490558

Signal-Detection Analyses of Conditional Discrimination and Delayed Matching-to-Sample Performance

ERIC Educational Resources Information Center

Alsop, Brent

2004-01-01

Quantitative analyses of stimulus control and reinforcer control in conditional discriminations and delayed matching-to-sample procedures often encounter a problem; it is not clear how to analyze data when subjects have not made errors. The present article examines two common methods for overcoming this problem. Monte Carlo simulations of…

In the Blink of an Eye: Investigating the Role of Awareness in Fear Responding by Measuring the Latency of Startle Potentiation

PubMed Central

Åsli, Ole; Flaten, Magne A.

2012-01-01

The latency of startle reflex potentiation may shed light on the aware and unaware processes underlying associative learning, especially associative fear learning. We review research suggesting that single-cue delay classical conditioning is independent of awareness of the contingency between the conditioned stimulus (CS) and the unconditioned stimulus (US). Moreover, we discuss research that argues that conditioning independent of awareness has not been proven. Subsequently, three studies from our lab are presented that have investigated the role of awareness in classical conditioning, by measuring the minimum latency from CS onset to observed changes in reflexive behavior. In sum, research using this method shows that startle is potentiated 30 to 100 ms after CS onset following delay conditioning. Following trace fear conditioning, startle is potentiated 1500 ms after CS presentation. These results indicate that the process underlying delay conditioned responding is independent of awareness, and that trace fear conditioned responding is dependent on awareness. Finally, this method of investigating the role of awareness is discussed and future research possibilities are proposed. PMID:24962686

Finite-Dimensional Representations for Controlled Diffusions with Delay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Federico, Salvatore, E-mail: salvatore.federico@unimi.it; Tankov, Peter, E-mail: tankov@math.univ-paris-diderot.fr

2015-02-15

We study stochastic delay differential equations (SDDE) where the coefficients depend on the moving averages of the state process. As a first contribution, we provide sufficient conditions under which the solution of the SDDE and a linear path functional of it admit a finite-dimensional Markovian representation. As a second contribution, we show how approximate finite-dimensional Markovian representations may be constructed when these conditions are not satisfied, and provide an estimate of the error corresponding to these approximations. These results are applied to optimal control and optimal stopping problems for stochastic systems with delay.

Group delay spread analysis of coupled-multicore fibers: A comparison between weak and tight bending conditions

NASA Astrophysics Data System (ADS)

Fujisawa, Takeshi; Saitoh, Kunimasa

2017-06-01

Group delay spread of coupled three-core fiber is investigated based on coupled-wave theory. The differences between supermode and discrete core mode models are thoroughly investigated to reveal applicability of both models for specific fiber bending condition. A macrobending with random twisting is taken into account for random modal mixing in the fiber. It is found that for weakly bent condition, both supermode and discrete core mode models are applicable. On the other hand, for strongly bent condition, the discrete core mode model should be used to account for increased differential modal group delay for the fiber without twisting and short correlation length, which were experimentally observed recently. Results presented in this paper indicate the discrete core mode model is superior to the supermode model for the analysis of coupled-multicore fibers for various bent condition. Also, for estimating GDS of coupled-multicore fiber, it is critically important to take into account the fiber bending condition.

Feasibility of using administrative data for identifying medical reasons to delay hip fracture surgery: a Canadian database study.

PubMed

Guy, Pierre; Sheehan, Katie J; Morin, Suzanne N; Waddell, James; Dunbar, Michael; Harvey, Edward; Sirett, Susan; Sobolev, Boris; Kuramoto, Lisa; Tang, Michael

2017-10-05

Failure to account for medically necessary delays may lead to an underestimation of early surgery benefits. This study investigated the feasibility of using administrative data to identify the National Institute for Health and Care Excellence (NICE) 124 guideline list of conditions that appropriately delay hip fracture surgery. We assembled a list of diagnosis and procedure codes to reflect the NICE 124 conditions. The list was reviewed and updated by an advanced clinical coder. The list was refined by five clinical experts. We then screened Canadian Institute for Health Information discharge abstracts for 153 918 patients surgically treated for a non-pathological first hip fracture between 1 January 2004 and 31 December 2012 for diagnosis codes present on admission and procedure codes that antedated hip fracture surgery. We classified abstracts as having medical reasons for delaying surgery based on the presence of these codes. In total, 10 237 (6.7%; 95% CI 6.5% to 6.8%) patients had diagnostic and procedure codes indicating medical reasons for delay. The most common reasons for medical delay were exacerbation of a chronic chest condition (35.9%) and acute chest infection (23.2%). The proportion of patients with reasons for medical delays increased with time from admission to surgery: 3.9% (95% CI 3.6% to 4.1%) for same day surgery; 4.7% (95% CI 4.5% to 4.8%) for surgery 1 day after admission; 7.1% (95% CI 6.9% to 7.4%) for surgery 2 days after admission; and 15.5% (95% CI 15.1% to 16.0%) for surgery more than 2 days after admission. The trend was seen for admissions on weekday working hours, weekday after hours and on weekends. Administrative data can be considered to identify conditions that appropriately delay hip fracture surgery. Accounting for medically necessary delays can improve estimates of the effectiveness of early surgery. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Delay and trace fear conditioning in C57BL/6 and DBA/2 mice: issues of measurement and performance.

PubMed

Tipps, Megan E; Raybuck, Jonathan D; Buck, Kari J; Lattal, K Matthew

2014-08-01

Strain comparison studies have been critical to the identification of novel genetic and molecular mechanisms in learning and memory. However, even within a single learning paradigm, the behavioral data for the same strain can vary greatly, making it difficult to form meaningful conclusions at both the behavioral and cellular level. In fear conditioning, there is a high level of variability across reports, especially regarding responses to the conditioned stimulus (CS). Here, we compare C57BL/6 and DBA/2 mice using delay fear conditioning, trace fear conditioning, and a nonassociative condition. Our data highlight both the significant strain differences apparent in these fear conditioning paradigms and the significant differences in conditioning type within each strain. We then compare our data to an extensive literature review of delay and trace fear conditioning in these two strains. Finally, we apply a number of commonly used baseline normalization approaches to compare how they alter the reported differences. Our findings highlight three major sources of variability in the fear conditioning literature: CS duration, number of CS presentations, and data normalization to baseline measures. © 2014 Tipps et al.; Published by Cold Spring Harbor Laboratory Press.

Mathematical analysis of a nutrient-plankton system with delay.

PubMed

Rehim, Mehbuba; Zhang, Zhenzhen; Muhammadhaji, Ahmadjan

2016-01-01

A mathematical model describing the interaction of nutrient-plankton is investigated in this paper. In order to account for the time needed by the phytoplankton to mature after which they can release toxins, a discrete time delay is incorporated into the system. Moreover, it is also taken into account discrete time delays which indicates the partially recycled nutrient decomposed by bacteria after the death of biomass. In the first part of our analysis the sufficient conditions ensuring local and global asymptotic stability of the model are obtained. Next, the existence of the Hopf bifurcation as time delay crosses a threshold value is established and, meanwhile, the phenomenon of stability switches is found under certain conditions. Numerical simulations are presented to illustrate the analytical results.

Nonconvulsive status epilepticus and neurodevelopmental delay.

PubMed

Dirik, Eray; Yiş, Uluç; Hüdaoglu, Orkide; Kurul, Semra

2006-09-01

Nonconvulsive status epilepticus is characterized by continuous or near continuous epileptiform discharges on electroencephalography without overt motor or sensory phenomena. It is a symptomatic condition related to a disease such as epileptic encephalopathy or a metabolic disorder. Children with isolated nonconvulsive status epilepticus rarely present with global neurodevelopmental delay. This report describes an 18-month-old male who presented with global neurodevelopmental delay and decreased alertness in whom electrical status epilepticus during sleep, which is a form of nonconvulsive status epilepticus, was determined. Metabolic investigations and cranial magnetic resonance imaging were normal. He began to achieve developmental milestones after treatment with valproic acid. Although rare, pediatric neurologists and pediatricians must be aware of this condition in making the differential diagnosis of global neurodevelopmental delay and decreased alertness.

A new delay-independent condition for global robust stability of neural networks with time delays.

PubMed

Samli, Ruya

2015-06-01

This paper studies the problem of robust stability of dynamical neural networks with discrete time delays under the assumptions that the network parameters of the neural system are uncertain and norm-bounded, and the activation functions are slope-bounded. By employing the results of Lyapunov stability theory and matrix theory, new sufficient conditions for the existence, uniqueness and global asymptotic stability of the equilibrium point for delayed neural networks are presented. The results reported in this paper can be easily tested by checking some special properties of symmetric matrices associated with the parameter uncertainties of neural networks. We also present a numerical example to show the effectiveness of the proposed theoretical results. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sexual orientation-related differences in prepulse inhibition of the human startle response.

PubMed

Rahman, Qazi; Kumari, Veena; Wilson, Glenn D

2003-10-01

Prepulse inhibition (PPI) refers to a reduction in the startle response to a strong sensory stimulus when this stimulus is preceded by a weaker stimulus--the prepulse. PPI reflects a nonlearned sensorimotor gating mechanism and also shows a robust gender difference, with women exhibiting lower PPI than men. The present study examined the eyeblink startle responses to acoustic stimuli of 59 healthy heterosexual and homosexual men and women. Homosexual women showed significantly masculinized PPI compared with heterosexual women, whereas no difference was observed in PPI between homosexual and heterosexual men. These data provide the first evidence for within-gender differences in basic sensorimotor gating mechanisms and implicate the known neural substrates of PPI in human sexual orientation. (c) 2003 APA, all rights reserved

Eliminating the Attentional Blink through Binaural Beats: A Case for Tailored Cognitive Enhancement

PubMed Central

Reedijk, Susan A.; Bolders, Anne; Colzato, Lorenza S.; Hommel, Bernhard

2015-01-01

Enhancing human cognitive performance is a topic that continues to spark scientific interest. Studies into cognitive-enhancement techniques often fail to take inter-individual differences into account, however, which leads to underestimation of the effectiveness of these techniques. The current study investigated the effect of binaural beats, a cognitive-enhancement technique, on attentional control in an attentional blink (AB) task. As predicted from a neurocognitive approach to cognitive control, high-frequency binaural beats eliminated the AB, but only in individuals with low spontaneous eye-blink rates (indicating low striatal dopamine levels). This suggests that the way in which cognitive-enhancement techniques, such as binaural beats, affect cognitive performance depends on inter-individual differences. PMID:26089802

Negative Self-Focused Cognitions Mediate the Effect of Trait Social Anxiety on State Anxiety

PubMed Central

Schulz, Stefan M.; Alpers, Georg W.; Hofmann, Stefan G.

2008-01-01

The cognitive model of social anxiety predicts that negative self-focused cognitions increase anxiety when anticipating social threat. To test this prediction, 36 individuals were asked to anticipate and perform a public speaking task. During anticipation, negative self-focused cognitions or relaxation were experimentally induced while self-reported anxiety, autonomic arousal (heart rate, heart rate variability, skin conductance level), and acoustic eye-blink startle response were assessed. As predicted, negative self-focused cognitions mediated the effects of trait social anxiety on self-reported anxiety and heart rate variability during negative anticipation. Furthermore, trait social anxiety predicted increased startle amplitudes. These findings support a central assumption of the cognitive model of social anxiety. PMID:18321469

Understanding Cervicogenic Headache

PubMed Central

Chua, Nicholas H L; Suijlekom, Hans V; Wilder-Smith, Oliver H; Vissers, Kris C P

2012-01-01

The purported mechanism underlying the development and progression of cervicogenic headache (CEH) is the convergence of sensory inputs at the trigeminocervical nucleus. This mechanism explains the radiation of pain from the neck or the occipitonuchal area and its spread to the oculo-fronto-temporal region; it also explains the recurrent headaches caused by improper neck postures or external pressure to the structures in the neck and the occipital region. These neural connectivity mechanisms involving the trigeminal nucleus are also evident from the eyeblink reflex and findings of quantitative sensory testing (QST). Understanding the mechanisms underlying the development of CEH is important because it will not only provide a better treatment outcome but will also allow practitioners to appreciate the variability of symptomatic presentations in these patients. PMID:24223325

TBC1D24 mutation associated with focal epilepsy, cognitive impairment and a distinctive cerebro-cerebellar malformation.

PubMed

Afawi, Zaid; Mandelstam, Simone; Korczyn, Amos D; Kivity, Sara; Walid, Simri; Shalata, Adel; Oliver, Karen L; Corbett, Mark; Gecz, Jozef; Berkovic, Samuel F; Jackson, Graeme D

2013-07-01

We describe the clinical and radiological features of a family with a homozygous mutation in TBC1D24. The phenotype comprised onset of focal seizures at 2 months with prominent eye-blinking, facial and limb jerking with an oral sensory aura. These were controllable with medication but persisted into adult life. Associated features were mild to moderate intellectual disability and cerebellar features. MRI showed subtle cortical thickening with cerebellar atrophy and high signal confined to the ansiform lobule. The disorder is allelic with familial infantile myoclonic epilepsy, where intellect and neurologic examination are normal, highlighting the phenotypic variation with mutations of TBC1D24. Copyright © 2013 Elsevier B.V. All rights reserved.

The influence of memory and attention on the ear advantage in dichotic listening.

PubMed

D'Anselmo, Anita; Marzoli, Daniele; Brancucci, Alfredo

2016-12-01

The role of memory retention and attentional control on hemispheric asymmetry was investigated using a verbal dichotic listening paradigm, with the consonant-vowel syllables (/ba/,/da/,/ga/,/ka/,/pa/and/ta/), while manipulating the focus of attention and the time interval between stimulus and response. Attention was manipulated using three conditions: non-forced (NF), forced left (FL) and forced right (FR) attention. Memory involvement was varied using four delays (0, 1, 3 and 4 s) between stimulus presentation and response. Results showed a significant right ear advantage (REA) in the NF condition and an increased REA in the FR condition. A left ear advantage (LEA) was found in FL condition. The REA increased significantly in the NF attention condition at the 3-s compared to the 0-s delay and in the FR condition at the 1-s compared to the 0-s delay. No modulation of the left ear advantage was observed in the FL condition. These results are discussed in terms of an interaction between attentional processes and memory retention. Copyright © 2016 Elsevier B.V. All rights reserved.

Short-term total sleep deprivation alters delay-conditioned memory in the rat.

PubMed

Tripathi, Shweta; Jha, Sushil K

2016-06-01

Short-term sleep deprivation soon after training may impair memory consolidation. Also, a particular sleep stage or its components increase after learning some tasks, such as negative and positive reinforcement tasks, avoidance tasks, and spatial learning tasks, and so forth. It suggests that discrete memory types may require specific sleep stage or its components for their optimal processing. The classical conditioning paradigms are widely used to study learning and memory but the role of sleep in a complex conditioned learning is unclear. Here, we have investigated the effects of short-term sleep deprivation on the consolidation of delay-conditioned memory and the changes in sleep architecture after conditioning. Rats were trained for the delay-conditioned task (for conditioning, house-light [conditioned stimulus] was paired with fruit juice [unconditioned stimulus]). Animals were divided into 3 groups: (a) sleep deprived (SD); (b) nonsleep deprived (NSD); and (c) stress control (SC) groups. Two-way ANOVA revealed a significant interaction between groups and days (training and testing) during the conditioned stimulus-unconditioned stimulus presentation. Further, Tukey post hoc comparison revealed that the NSD and SC animals exhibited significant increase in performances during testing. The SD animals, however, performed significantly less during testing. Further, we observed that wakefulness and NREM sleep did not change after training and testing. Interestingly, REM sleep increased significantly on both days compared to baseline more specifically during the initial 4-hr time window after conditioning. Our results suggest that the consolidation of delay-conditioned memory is sleep-dependent and requires augmented REM sleep during an explicit time window soon after training. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

[Intermodal timing cues for audio-visual speech recognition].

PubMed

Hashimoto, Masahiro; Kumashiro, Masaharu

2004-06-01

The purpose of this study was to investigate the limitations of lip-reading advantages for Japanese young adults by desynchronizing visual and auditory information in speech. In the experiment, audio-visual speech stimuli were presented under the six test conditions: audio-alone, and audio-visually with either 0, 60, 120, 240 or 480 ms of audio delay. The stimuli were the video recordings of a face of a female Japanese speaking long and short Japanese sentences. The intelligibility of the audio-visual stimuli was measured as a function of audio delays in sixteen untrained young subjects. Speech intelligibility under the audio-delay condition of less than 120 ms was significantly better than that under the audio-alone condition. On the other hand, the delay of 120 ms corresponded to the mean mora duration measured for the audio stimuli. The results implied that audio delays of up to 120 ms would not disrupt lip-reading advantage, because visual and auditory information in speech seemed to be integrated on a syllabic time scale. Potential applications of this research include noisy workplace in which a worker must extract relevant speech from all the other competing noises.

Delayed matching to two-picture samples by individuals with and without disabilities: an analysis of the role of naming.

PubMed

Gutowski, Stanley J; Stromer, Robert

2003-01-01

Delayed matching to complex, two-picture samples (e.g., cat-dog) may be improved when the samples occasion differential verbal behavior. In Experiment 1, individuals with mental retardation matched picture comparisons to identical single-picture samples or to two-picture samples, one of which was identical to a comparison. Accuracy scores were typically high on single-picture trials under both simultaneous and delayed matching conditions. Scores on two-picture trials were also high during the simultaneous condition but were lower during the delay condition. However, scores improved on delayed two-picture trials when each of the sample pictures was named aloud before comparison responding. Experiment 2 replicated these results with preschoolers with typical development and a youth with mental retardation. Sample naming also improved the preschoolers' matching when the samples were pairs of spoken names and the correct comparison picture matched one of the names. Collectively, the participants could produce the verbal behavior that might have improved performance, but typically did not do so unless the procedure required it. The success of the naming intervention recommends it for improving the observing and remembering of multiple elements of complex instructional stimuli.

The Effects of Condom Availability on College Women's Sexual Discounting.

PubMed

Lemley, Shea M; Jarmolowicz, David P; Parkhurst, Daniel; Celio, Mark A

2018-04-01

College students commonly engage in risky sexual behaviors, such as casual sexual encounters and inconsistent condom use. Discounting paradigms that examine how individuals devalue rewards due to their delay or uncertainty have been used to improve our understanding of behavioral problems, including sexual risk. The current study assessed relations between college women's sexual partners discounting and risky sexual behavior. In this study, college women (N = 42) completed two sexual partners delay discounting tasks that assessed how choices among hypothetical sexual partners changed across a parametric range of delays in two conditions: condom availability and condom unavailability. Participants also completed two sexual partners probability discounting tasks that assessed partner choices across a parametric range of probabilities in condom availability and unavailability conditions. Additionally, participants reported risky sexual behavior on the Sexual Risk Survey (SRS). Participants discounted delayed partners more steeply in the condom availability condition, but those differences were significant only for those women with three or fewer lifetime sexual partners. There were no consistent differences in discounting rate across condom availability conditions for probability discounting. Sexual partners discounting measures correlated with risky sexual behaviors as measured by the SRS, but a greater number of significant relations were observed with the condoms-unavailable delay discounting task. These findings suggest the importance of examining the interaction of inconsistent condom use and multiple partners in examinations of sexual decision-making.

On the theory of singular optimal controls in dynamic systems with control delay

NASA Astrophysics Data System (ADS)

Mardanov, M. J.; Melikov, T. K.

2017-05-01

An optimal control problem with a control delay is considered, and a more broad class of singular (in classical sense) controls is investigated. Various sequences of necessary conditions for the optimality of singular controls in recurrent form are obtained. These optimality conditions include analogues of the Kelley, Kopp-Moyer, R. Gabasov, and equality-type conditions. In the proof of the main results, the variation of the control is defined using Legendre polynomials.

Comparison of Inner Ear Contrast Enhancement among Patients with Unilateral Inner Ear Symptoms in MR Images Obtained 10 Minutes and 4 Hours after Gadolinium Injection.

PubMed

Kim, T Y; Park, D W; Lee, Y J; Lee, J Y; Lee, S H; Chung, J H; Lee, S

2015-12-01

Recently 4-hour delayed-enhanced 3D-FLAIR MR imaging has been used in pathophysiologic analysis of the inner ear in many auditory diseases, including sudden sensorineural hearing loss, but comparison among different time points is not clear in patients with unilateral inner ear symptoms. We compared the signal-intensity ratios of the inner ears in patients with unilateral inner ear symptoms on 10-minute delayed-enhanced and 4-hour delayed-enhanced 3D-FLAIR MR images after IV gadolinium injection. The 10-minute delayed-enhanced and 4-hour delayed-enhanced 3D-FLAIR MR images were retrospectively analyzed. Signal-intensity ratios between the cerebellum and inner ear structures, such as the cochleae, vestibules, and vestibulocochlear nerve were assessed. Multiple comparisons were performed. Signal-intensity ratios of the affected cochleae, vestibules, and vestibulocochlear nerve were higher than those of unaffected sides in both 10-minute delayed-enhanced and 4-hour delayed-enhanced images. At the affected side, signal-intensity ratios of the vestibulocochlear nerve were higher in patients with nonsudden sensorineural hearing loss than in those with sudden sensorineural hearing loss on both 10-minute delayed-enhanced and 4-hour delayed-enhanced images. The signal-intensity ratios of some affected inner ear structures were higher than those of the unaffected sides in a group of 30 patients with sudden sensorineural hearing loss and 20 patients with nonsudden sensorineural hearing loss on 10-minute delayed-enhanced and 4-hour delayed-enhanced images. Signal-intensity ratios of the inner ear show statistically significant increases in many diseases, especially neuritis, in 10-minute delayed-enhanced and 4-hour delayed-enhanced images. The 4-hour delayed-enhanced images may be superior in neural inflammatory-dominant conditions, while 10-minute delayed-enhanced images may be superior in neural noninflammatory-dominant conditions. © 2015 by American Journal of Neuroradiology.

Global asymptotic stability analysis of bidirectional associative memory neural networks with time delays.

PubMed

Arik, Sabri

2005-05-01

This paper presents a sufficient condition for the existence, uniqueness and global asymptotic stability of the equilibrium point for bidirectional associative memory (BAM) neural networks with distributed time delays. The results impose constraint conditions on the network parameters of neural system independently of the delay parameter, and they are applicable to all continuous nonmonotonic neuron activation functions. It is shown that in some special cases of the results, the stability criteria can be easily checked. Some examples are also given to compare the results with the previous results derived in the literature.

Dynamics of a stochastic delayed SIR epidemic model with vaccination and double diseases driven by Lévy jumps

NASA Astrophysics Data System (ADS)

Liu, Qun; Jiang, Daqing; Shi, Ningzhong; Hayat, Tasawar

2018-02-01

In this paper, we study the dynamics of a stochastic delayed SIR epidemic model with vaccination and double diseases which make the research more complex. The environment variability in this paper is characterized by white noise and Lévy noise. We establish sufficient conditions for extinction and persistence in the mean of the two epidemic diseases. It is shown that: (i) time delay and Lévy noise have important effects on the persistence and extinction of epidemic diseases; (ii) two diseases can coexist under certain conditions.

Choice between Single and Multiple Reinforcers in Concurrent-Chains Schedules

ERIC Educational Resources Information Center

Mazur, James E.

2006-01-01

Pigeons responded on concurrent-chains schedules with equal variable-interval schedules as initial links. One terminal link delivered a single reinforcer after a fixed delay, and the other terminal link delivered either three or five reinforcers, each preceded by a fixed delay. Some conditions included a postreinforcer delay after the single…

36 CFR 223.226 - Term adjustments for force majeure delay.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Term adjustments for force majeure delay. 223.226 Section 223.226 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF... Conditions and Provisions § 223.226 Term adjustments for force majeure delay. Contracts or other authorizing...

The Influence of Emotion on Immediate and Delayed Retention: Levinger and Clark Reconsidered.

ERIC Educational Resources Information Center

Parkin, Alan J.; And Others

1982-01-01

Examined effect of emotion on recall of self-generated paired associates under conditions of immediate and delayed retention. Results showed that, with immediate retention, recall of associates to emotional stimuli was significantly lower than to neutral stimuli and, with delayed retention, associations to emotional stimuli were better recalled.…

How additional visual feedback of the movements between center of pressure and vertically projected center of gravity can be used by hemiparetic patients.

PubMed

Rougier, Patrice R; Boudrahem, Samir

2012-01-01

In healthy adults, the beneficial effect of providing additional visual feedback (VFB) with a delay of either the center of pressure (CP) or the difference between CP movements and center of gravity (CP-CGv) movements was previously demonstrated and explained by their capacity to decrease their CP-CGv movements. The present study seeks to demonstrate whether similar trends could be observed in hemiparetic patients. Posturographic measurements were recorded in 56 hemiparetic patients in 3 VFB conditions: (1) CP in real time (VFBCP0), (2) CP with a 600-ms delay (VFBCP600), and (3) CP-CGv with a 600-ms delay (VFBCP-CG600). A condition without VFB (eyes open [EO]) was also included. The individual capacity to lower CP-CGv movements as compared to the reference VFBCP0 condition was assessed using dependency coefficients (ie, average surface covered by the CP-CGv displacements in an experimental condition relative to the VFBCP0 condition) in the VFBCP600, VFBCP-CG600, and EO conditions. Reduced CP-CGv movements were only obtained for half of the patients for the conditions with delay or without VFB. Significant linear correlations revealed that the most successful patients are characterized by reduced CP-CGv movements in these conditions and in the EO condition. In contrast, a poor correlation was found with the patients' clinical scores. Based on the behavioral profile of a patient able to use these VFB techniques effectively, this study emphasizes the complementary nature of the various conditions proposed by the VFB technique and provides insights for establishing rehabilitation protocols based on this VFB technique.

Theoretical foundations for traditional and generalized sensitivity functions for nonlinear delay differential equations.

PubMed

Banks, H Thomas; Robbins, Danielle; Sutton, Karyn L

2013-01-01

In this paper we present new results for differentiability of delay systems with respect to initial conditions and delays. After motivating our results with a wide range of delay examples arising in biology applications, we further note the need for sensitivity functions (both traditional and generalized sensitivity functions), especially in control and estimation problems. We summarize general existence and uniqueness results before turning to our main results on differentiation with respect to delays, etc. Finally we discuss use of our results in the context of estimation problems.

Delay-Induced Attenuation of Latent Inhibition with a Conditioned Emotional Response Depends on CS-US Strength

ERIC Educational Resources Information Center

De la Casa, Luis G.; Diaz, Estrella; Lubow, R.E.

2005-01-01

Latent Inhibition (LI) attenuation when a long delay is introduced between acquisition and test phases has been repeatedly observed using aversive conditioning procedures (e.g., Aguado, Symonds, & Hall, 1994). This effect has been used as evidence to support those theories that consider LI to be the result of a retrieval failure. We designed three…

The processing of consonants and vowels during letter identity and letter position assignment in visual-word recognition: an ERP study.

PubMed

Vergara-Martínez, Marta; Perea, Manuel; Marín, Alejandro; Carreiras, Manuel

2011-09-01

Recent research suggests that there is a processing distinction between consonants and vowels in visual-word recognition. Here we conjointly examine the time course of consonants and vowels in processes of letter identity and letter position assignment. Event related potentials (ERPs) were recorded while participants read words and pseudowords in a lexical decision task. The stimuli were displayed under different conditions in a masked priming paradigm with a 50-ms SOA: (i) identity/baseline condition e.g., chocolate-CHOCOLATE); (ii) vowels-delayed condition (e.g., choc_l_te-CHOCOLATE); (iii) consonants-delayed condition (cho_o_ate-CHOCOLATE); (iv) consonants-transposed condition (cholocate-CHOCOLATE); (v) vowels-transposed condition (chocalote-CHOCOLATE), and (vi) unrelated condition (editorial-CHOCOLATE). Results showed earlier ERP effects and longer reaction times for the delayed-letter compared to the transposed-letter conditions. Furthermore, at early stages of processing, consonants may play a greater role during letter identity processing. Differences between vowels and consonants regarding letter position assignment are discussed in terms of a later phonological level involved in lexical retrieval. Copyright © 2010 Elsevier Inc. All rights reserved.

Exponential synchronization of delayed neutral-type neural networks with Lévy noise under non-Lipschitz condition

NASA Astrophysics Data System (ADS)

Ma, Shuo; Kang, Yanmei

2018-04-01

In this paper, the exponential synchronization of stochastic neutral-type neural networks with time-varying delay and Lévy noise under non-Lipschitz condition is investigated for the first time. Using the general Itô's formula and the nonnegative semi-martingale convergence theorem, we derive general sufficient conditions of two kinds of exponential synchronization for the drive system and the response system with adaptive control. Numerical examples are presented to verify the effectiveness of the proposed criteria.

Males and Females Respond Differently to Controllability and Antidepressant Treatment

PubMed Central

Leuner, Benedetta; Mendolia-Loffredo, Sabrina; Shors, Tracey J.

2012-01-01

Background Women are much more likely to suffer from stress-related mental illness than men; yet few, if any, animal models for such sex differences exist. Previously, we reported that exposure to an acute stressor enhances learning in male rats yet severely impairs learning in female rats. Here, we tested whether these opposite effects in males versus females could be prevented by establishing control over the stressor or by antidepressant treatment. Methods Learning was assessed using the hippocampal-dependent task of trace eyeblink conditioning. In the first experiment, groups of male and female rats were exposed to controllable or uncontrollable stress and trained. In a second experiment, they were exposed to an uncontrollable stressor after chronic treatment with the antidepressant fluoxetine (Prozac). In a final experiment, females were exposed to uncontrollable stress after acute treatment with fluoxetine. Results Establishing control over the stressful experience eliminated the detrimental effect of stress on learning in females as well as the enhancing effect of stress in males. Moreover, chronic but not acute treatment with fluoxetine prevented the learning deficit in females after exposure to stress. Treatment with fluoxetine did not alter the male response to stress. Conclusions These data indicate that males and females not only respond in opposite directions to the same stressful event but also respond differently to controllability and antidepressant treatments. PMID:15601607

Foregone benefits of important food crop improvements in Sub-Saharan Africa

PubMed Central

2017-01-01

A number of new crops have been developed that address important traits of particular relevance for smallholder farmers in Africa. Scientists, policy makers, and other stakeholders have raised concerns that the approval process for these new crops causes delays that are often scientifically unjustified. This article develops a real option model for the optimal regulation of a risky technology that enhances economic welfare and reduces malnutrition. We consider gradual adoption of the technology and show that delaying approval reduces uncertainty about perceived risks of the technology. Optimal conditions for approval incorporate parameters of the stochastic processes governing the dynamics of risk. The model is applied to three cases of improved crops, which either are, or are expected to be, delayed by the regulatory process. The benefits and costs of the crops are presented in a partial equilibrium that considers changes in adoption over time and the foregone benefits caused by a delay in approval under irreversibility and uncertainty. We derive the equilibrium conditions where the net-benefits of the technology equal the costs that would justify a delay. The sooner information about the safety of the technology arrive, the lower the costs for justifying a delay need to be i.e. it pays more to delay. The costs of a delay can be substantial: e.g. a one year delay in approval of the pod-borer resistant cowpea in Nigeria will cost the country about 33 million USD to 46 million USD and between 100 and 3,000 lives. PMID:28749984

Choice between delayed food and immediate opioids in rats: treatment effects and individual differences.

PubMed

Panlilio, Leigh V; Secci, Maria E; Schindler, Charles W; Bradberry, Charles W

2017-11-01

Addiction involves maladaptive choice behavior in which immediate drug effects are valued more than delayed nondrug rewards. To model this behavior and extend our earlier work with the prescription opioid oxycodone, we allowed rats to choose between immediate intravenous delivery of the short-acting opioid remifentanil and delayed delivery of highly palatable food pellets. Treatment drugs were tested on a baseline where remifentanil was preferred over food. Treatment with a high dose of the opioid antagonist naltrexone decreased but did not reverse the preference for remifentanil. Treatment with the serotonin 5-HT 2C agonist lorcaserin decreased remifentanil and food self-administration nonselectively. Across conditions in which the alternative to delayed food was either a moderate dose of oxycodone, a moderate or high dose of remifentanil, a smaller more immediate delivery of food, or timeout with no primary reinforcement, choice was determined by both the length of the delay and the nature of the alternative option. Delayed food was discounted most steeply when the alternative was a high dose of remifentanil, which was preferred over food when food was delayed by 30 s or more. Within-subject comparisons showed no evidence for trait-like impulsivity or sensitivity to delay across these conditions. Choice was determined more by the current contingencies of reinforcement than by innate individual differences. This finding suggests that people might develop steep delay-discounting functions because of the contingencies in their environment, and it supports the use of contingency management to enhance the relative value of delayed nondrug reinforcers.

Investigation of stability in a two-delay model of the ultradian oscillations in glucose-insulin regulation

NASA Astrophysics Data System (ADS)

Huard, B.; Easton, J. F.; Angelova, M.

2015-09-01

In this paper, a two-delay model for the ultradian oscillatory behaviour of the glucose-insulin regulation system is studied. Hill functions are introduced to model nonlinear physiological interactions within this system and ranges on parameters reproducing biological oscillations are determined on the basis of analytical and numerical considerations. Local and global stability are investigated and delay-dependent conditions are obtained through the construction of Lyapunov-Krasovskii functionals. The effect of Hill parameters on these conditions, as well as the boundary of the stability region in the delay domain, are established for the first time. Numerical simulations demonstrate that the model with Hill functions represents well the oscillatory behaviour of the system with the advantage of incorporating new meaningful parameters. The influence of the time delays on the period of oscillations and the sensitivity of the latter to model parameters, in particular glucose infusion, are investigated. The model can contribute to the better understanding and treatment of diabetes.

Global exponential stability of BAM neural networks with time-varying delays and diffusion terms

NASA Astrophysics Data System (ADS)

Wan, Li; Zhou, Qinghua

2007-11-01

The stability property of bidirectional associate memory (BAM) neural networks with time-varying delays and diffusion terms are considered. By using the method of variation parameter and inequality technique, the delay-independent sufficient conditions to guarantee the uniqueness and global exponential stability of the equilibrium solution of such networks are established.

The Effects of Inflation and Interest Rates on Delay Discounting in Human Behavior

ERIC Educational Resources Information Center

Kawashima, Kentaro

2006-01-01

Interest and inflation rates may be major determinants of delay discounting, but these variables have not been controlled in past experiments because they depend on macroeconomic conditions. This study uses a computer game-like task to investigate the effects of inflation rates on people's subjective valuation of delayed rewards. During the task,…

The Effects of Four-Hour Delay of PUnishment under Two Conditions of Verbal Instruction

ERIC Educational Resources Information Center

Verna, Gary B.

1977-01-01

The effects of 4-hour delay of punishment (withdrawal of reward) on response inhibition was studied with 24 fourth-grade children. Results showed that verbal expression of the punishment contingency allows the 10-year-old child to profit from 4-hour delayed punishment as much as immediate punishment. (Author/JMB)

Approximate controllability of a system of parabolic equations with delay

NASA Astrophysics Data System (ADS)

Carrasco, Alexander; Leiva, Hugo

2008-09-01

In this paper we give necessary and sufficient conditions for the approximate controllability of the following system of parabolic equations with delay: where [Omega] is a bounded domain in , D is an n×n nondiagonal matrix whose eigenvalues are semi-simple with nonnegative real part, the control and B[set membership, variant]L(U,Z) with , . The standard notation zt(x) defines a function from [-[tau],0] to (with x fixed) by zt(x)(s)=z(t+s,x), -[tau][less-than-or-equals, slant]s[less-than-or-equals, slant]0. Here [tau][greater-or-equal, slanted]0 is the maximum delay, which is supposed to be finite. We assume that the operator is linear and bounded, and [phi]0[set membership, variant]Z, [phi][set membership, variant]L2([-[tau],0];Z). To this end: First, we reformulate this system into a standard first-order delay equation. Secondly, the semigroup associated with the first-order delay equation on an appropriate product space is expressed as a series of strongly continuous semigroups and orthogonal projections related with the eigenvalues of the Laplacian operator (); this representation allows us to reduce the controllability of this partial differential equation with delay to a family of ordinary delay equations. Finally, we use the well-known result on the rank condition for the approximate controllability of delay system to derive our main result.

Effect of metrology time delay on overlay APC

NASA Astrophysics Data System (ADS)

Carlson, Alan; DiBiase, Debra

2002-07-01

The run-to-run control strategy of lithography APC is primarily composed of a feedback loop as shown in the diagram below. It is known that the insertion of a time delay in a feedback loop can cause degradation in control performance and could even cause a stable system to become unstable, if the time delay becomes sufficiently large. Many proponents of integrated metrology methods have cited the damage caused by metrology time delays as the primary justification for moving from a stand-alone to integrated metrology. While there is little dispute over the qualitative form of this argument, there has been very light published about the quantitative effects under real fab conditions - precisely how much control is lost due to these time delays. Another issue regarding time delays is that the length of these delays is not typically fixed - they vary from lot to lot and in some cases this variance can be large - from one hour on the short side to over 32 hours on the long side. Concern has been expressed that the variability in metrology time delays can cause undesirable dynamics in feedback loops that make it difficult to optimize feedback filters and gains and at worst could drive a system unstable. By using data from numerous fabs, spanning many sizes and styles of operation, we have conducted a quantitative study of the time delay effect on overlay run- to-run control. Our analysis resulted in the following conclusions: (1) There is a significant and material relationship between metrology time delay and overlay control under a variety of real world production conditions. (2) The run-to-run controller can be configured to minimize sensitivity to time delay variations. (3) The value of moving to integrated metrology can be quantified.

Lack of short-wavelength light during the school day delays dim light melatonin onset (DLMO) in middle school students.

PubMed

Figueiro, Mariana G; Rea, Mark S

2010-01-01

Circadian timing affects sleep onset. Delayed sleep onset can reduce sleep duration in adolescents required to awake early for a fixed school schedule. The absence of short-wavelength ("blue") morning light, which helps entrain the circadian system, can hypothetically delay sleep onset and decrease sleep duration in adolescents. The goal of this study was to investigate whether removal of short-wavelength light during the morning hours delayed the onset of melatonin in young adults. Dim light melatonin onset (DLMO) was measured in eleven 8th-grade students before and after wearing orange glasses, which removed short-wavelength light, for a five-day school week. DLMO was significantly delayed (30 minutes) after the five-day intervention, demonstrating that short-wavelength light exposure during the day can be important for advancing circadian rhythms in students. Lack of short-wavelength light in the morning has been shown to delay the circadian clock in controlled laboratory conditions. The results presented here are the first to show, outside laboratory conditions, that removal of short-wavelength light in the morning hours can delay DLMO in 8th-grade students. These field data, consistent with results from controlled laboratory studies, are directly relevant to lighting practice in schools.

Can the attention training technique turn one marshmallow into two? Improving children's ability to delay gratification.

PubMed

Murray, Joanne; Theakston, Anna; Wells, Adrian

2016-02-01

The seminal Marshmallow Test (Mischel & Ebbesen, 1970) has reliably demonstrated that children who can delay gratification are more likely to be emotionally stable and successful later in life. However, this is not good news for those children who can't delay. Therefore, this study aimed to explore whether a metacognitive therapy technique, Attention Training (ATT: Wells, 1990) can improve young children's ability to delay gratification. One hundred children participated. Classes of 5-6 year olds were randomly allocated to either the ATT or a no-intervention condition and were tested pre and post-intervention on ability to delay gratification, verbal inhibition (executive control), and measures of mood. The ATT intervention significantly increased (2.64 times) delay of gratification compared to the no-intervention condition. After controlling for age and months in school, the ATT intervention and verbal inhibition task performance were significant independent predictors of delay of gratification. These results provide evidence that ATT can improve children's self-regulatory abilities with the implication that this might reduce psychological vulnerability later in life. The findings highlight the potential contribution that the Self-Regulatory Executive Function (S-REF) model could make to designing techniques to enhance children's self-regulatory processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Two-actor conflict with time delay: A dynamical model

NASA Astrophysics Data System (ADS)

Qubbaj, Murad R.; Muneepeerakul, Rachata

2012-11-01

Recent mathematical dynamical models of the conflict between two different actors, be they nations, groups, or individuals, have been developed that are capable of predicting various outcomes depending on the chosen feedback strategies, initial conditions, and the previous states of the actors. In addition to these factors, this paper examines the effect of time delayed feedback on the conflict dynamics. Our analysis shows that under certain initial and feedback conditions, a stable neutral equilibrium of conflict may destabilize for some critical values of time delay, and the two actors may evolve to new emotional states. We investigate the results by constructing critical delay surfaces for different sets of parameters and analyzing results from numerical simulations. These results provide new insights regarding conflict and conflict resolution and may help planners in adjusting and assessing their strategic decisions.

Anticipated and zero-lag synchronization in motifs of delay-coupled systems

NASA Astrophysics Data System (ADS)

Mirasso, Claudio R.; Carelli, Pedro V.; Pereira, Tiago; Matias, Fernanda S.; Copelli, Mauro

2017-11-01

Anticipated and zero-lag synchronization have been observed in different scientific fields. In the brain, they might play a fundamental role in information processing, temporal coding and spatial attention. Recent numerical work on anticipated and zero-lag synchronization studied the role of delays. However, an analytical understanding of the conditions for these phenomena remains elusive. In this paper, we study both phenomena in systems with small delays. By performing a phase reduction and studying phase locked solutions, we uncover the functional relation between the delay, excitation and inhibition for the onset of anticipated synchronization in a sender-receiver-interneuron motif. In the case of zero-lag synchronization in a chain motif, we determine the stability conditions. These analytical solutions provide an excellent prediction of the phase-locked regimes of Hodgkin-Huxley models and Roessler oscillators.

Robust passivity analysis for discrete-time recurrent neural networks with mixed delays

NASA Astrophysics Data System (ADS)

Huang, Chuan-Kuei; Shu, Yu-Jeng; Chang, Koan-Yuh; Shou, Ho-Nien; Lu, Chien-Yu

2015-02-01

This article considers the robust passivity analysis for a class of discrete-time recurrent neural networks (DRNNs) with mixed time-delays and uncertain parameters. The mixed time-delays that consist of both the discrete time-varying and distributed time-delays in a given range are presented, and the uncertain parameters are norm-bounded. The activation functions are assumed to be globally Lipschitz continuous. Based on new bounding technique and appropriate type of Lyapunov functional, a sufficient condition is investigated to guarantee the existence of the desired robust passivity condition for the DRNNs, which can be derived in terms of a family of linear matrix inequality (LMI). Some free-weighting matrices are introduced to reduce the conservatism of the criterion by using the bounding technique. A numerical example is given to illustrate the effectiveness and applicability.

[Delayed reactions of active avoidance in white rats under conditions of an alternative choice].

PubMed

Ioseliani, T K; Sikharulidze, N I; Kadagishvili, A Ia; Mitashvili, E G

1995-01-01

It was shown that if the rats had been learned and then tested using conventional pain punishment of erroneous choice they were able to solve the problem of alternative choice only in the period of immediate action of conditioned stimuli. If the pain punishment for erroneously chosen compartment had not been applied in animal learning and testing, rats successfully solved the problem of alternative choice even after 5-second delay. Introduction of pain punishment led to the frustration of earlier elaborated delayed avoidance reactions. Analysis of the obtained results allows us to argue that the apparent incapability of white rats for solving the problems of delayed avoidance is caused by simultaneous action of two different mechanisms, i.e., those of the active and passive avoidance rather than short-term memory deficit.

Global stability results for a generalized Lotka-Volterra system with distributed delays. Applications to predator-prey and to epidemic systems.

PubMed

Beretta, E; Capasso, V; Rinaldi, F

1988-01-01

The paper contains an extension of the general ODE system proposed in previous papers by the same authors, to include distributed time delays in the interaction terms. The new system describes a large class of Lotka-Volterra like population models and epidemic models with continuous time delays. Sufficient conditions for the boundedness of solutions and for the global asymptotic stability of nontrivial equilibrium solutions are given. A detailed analysis of the epidemic system is given with respect to the conditions for global stability. For a relevant subclass of these systems an existence criterion for steady states is also given.

Mental simulation of drawing actions enhances delayed recall of a complex figure.

PubMed

De Lucia, Natascia; Trojano, Luigi; Senese, Vincenzo Paolo; Conson, Massimiliano

2016-10-01

Motor simulation implies that the same motor representations involved in action execution are re-enacted during observation or imagery of actions. Neurofunctional data suggested that observation of letters or abstract paintings can elicit simulation of writing or drawing gestures. We performed four behavioural experiments on right-handed healthy participants to test whether observation of a static and complex geometrical figure implies re-enactment of drawing actions. In Experiment 1, participants had to observe the stimulus without explicit instruction (observation-only condition), while performing irrelevant finger tapping (motor dual task), or while articulating irrelevant verbal material (verbal dual task). Delayed drawing of the stimulus was less accurate in the motor dual-task (interfering with simulation of hand actions) than in verbal dual-task and observation-only conditions. In Experiment 2, delayed drawing in the observation only was as accurate as when participants encoded the stimulus by copying it; in both conditions, accuracy was higher than when participants were instructed to observe the stimulus to recall it later verbally (observe to recall), thus being discouraged from engaging motor simulation. In Experiment 3, delayed drawing was as accurate in the observation-only condition as when participants imagined copying the stimulus; accuracy in both conditions was higher than in the observe-to-recall condition. In Experiment 4, in the observe-only condition participants who observed the stimulus with their right arm hidden behind their back were significantly less accurate than participants who had their left arm hidden. These findings converge in suggesting that mere observation of a geometrical stimulus can activate motor simulation and re-enactment of drawing actions.

Characteristic changes in the physiological components of cybersickness.

PubMed

Kim, Young Youn; Kim, Hyun Ju; Kim, Eun Nam; Ko, Hee Dong; Kim, Hyun Taek

2005-09-01

We investigated the characteristic changes in the physiology of cybersickness when subjects were exposed to virtual reality. Sixty-one participants experienced a virtual navigation for a total of 9.5 min, and were required to detect specific virtual objects. Three questionnaires for sickness susceptibility and immersive tendency were obtained before the navigation. Sixteen electrophysiological signals were recorded before, during, and after the navigation. The severity of cybersickness experienced by participants was reported from a simulator sickness questionnaire after the navigation. The total severity of cybersickness had a significant positive correlation with gastric tachyarrhythmia, eyeblink rate, heart period, and EEG delta wave and a negative correlation with EEG beta wave. These results suggest that cybersickness accompanies the pattern changes in the activities of the central and the autonomic nervous systems.

The nursing hypothesis: an evolutionary account of emotional modulation of the postauricular reflex.

PubMed

Johnson, Gabriella M; Valle-Inclán, Fernando; Geary, David C; Hackley, Steven A

2012-02-01

The postauricular reflex (PAR) is anomalous because it seems to be potentiated during positive emotions and inhibited during negative states, unlike eyeblink and other components of the startle reflex. Two evolutionary explanations based on simian facial emotion expressions were tested. Reflexes were elicited while 47 young adult volunteers made lip pursing or grimacing poses and viewed neutral, intimidating, or appetitive photos. The PAR was enhanced during appetitive slides, but only as subjects carried out the lip-pursing maneuver. These results support the nursing hypothesis, which assumes that infant mammals instinctively retract their pinnae while nursing in order to comfortably position the head. Appetitive emotions prime the ear-retraction musculature, even in higher primates whose postauricular muscles are vestigial. Copyright © 2011 Society for Psychophysiological Research.

[The effects of media violence on affective, cognitive, and physiological reactions of viewers].

PubMed

Yukawa, S; Yoshida, F

1998-06-01

The present study investigated the effects of media violence on affective, cognitive, and physiological reactions of viewers. Eighty undergraduate student (male = 40, female = 40) participated in the experiment. First, subjects were exposed to one of four violent films whose levels of violence and entertainment were based on ratings taken in a previous study (Yoshida & Yukawa, 1996). Immediately after viewing the film, subjects described their thoughts which occurred during watching the film and rated their affective reactions toward the film. Heart rate and eyeblink rate as indicators of physiological arousal were measured continuously before, during, and after the film. Results showed that the film high in violence elicited more negative and empty-powerless affects, while the film high in entertainment evoked more positive affects.

Looking at reality versus watching screens: Media professionalization effects on the spontaneous eyeblink rate

PubMed Central

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

2017-01-01

This article explores whether there are differences in visual perception of narrative between theatrical performances and screens, and whether media professionalization affects visual perception. We created a live theatrical stimulus and three audio-visual stimuli (each one with a different video editing style) having the same narrative, and displayed them randomly to participants (20 media professionals and 20 non-media professionals). For media professionals, watching movies on screens evoked a significantly lower spontaneous blink rate (SBR) than looking at theatrical performances. Media professionals presented a substantially lower SBR than non-media professionals when watching screens, and more surprisingly, also when seeing reality. According to our results, media professionals pay higher attention to both screens and the real world than do non-media professionals. PMID:28467449

Barriers to help-seeking in men diagnosed with benign colorectal diseases.

PubMed

Oberoi, Devesh V; Jiwa, Moyez; McManus, Alexandra; Hodder, Rupert

2015-01-01

To explore the help-seeking pathway for lower bowel symptoms in men diagnosed with benign bowel diseases. Semi-structured interviews were conducted. The data were analyzed thematically using Andersen's Model of Patient Delay as the theoretical framework. The major delaying factors were attribution of symptoms to self-limiting conditions, failure to make time to visit a GP, low expectation of help from the GP, fear of cancer diagnosis and embarrassment. The major causes of delay in help-seeking were related to the participants, whereas factors associated with treatment delay were less prominent in diagnostic delay.

The impact of cue learning, trait anxiety and genetic variation in the serotonin 1A receptor on contextual fear.

PubMed

Baas, Johanna M P; Heitland, Ivo

2015-12-01

In everyday life, aversive events are usually associated with certain predictive cues. Normally, the acquisition of these contingencies enables organisms to appropriately respond to threat. Presence of a threat cue clearly signals 'danger', whereas absence of such cues signals a period of 'safety'. Failure to identify threat cues may lead to chronic states of anxious apprehension in the context in which the threat has been imminent, which may be instrumental in the pathogenesis of anxiety disorders. In this study, existing data from 150 healthy volunteers in a cue and context virtual reality fear conditioning paradigm were reanalyzed. The aim was to further characterize the impact of cue acquisition and trait anxiety, and of a single nucleotide polymorphism in the serotonin 1A receptor gene (5-HTR1A, rs6295), on cued fear and contextual anxiety before and after fear contingencies were explicitly introduced. Fear conditioned responding was quantified with fear potentiation of the eyeblink startle reflex and subjective fear ratings. First, we replicated previous findings that the inability to identify danger cues during acquisition leads to heightened anxious apprehension in the threat context. Second, in subjects who did not identify the danger cue initially, contextual fear was associated with trait anxiety after the contingencies were explicitly instructed. Third, genetic variability within 5-HTR1A (rs6295) was associated with contextual fear independent of awareness or trait anxiety. These findings confirm that failure to acquire cue contingencies impacts contextual fear responding, in association with trait anxiety. The observed 5-HTR1A effect is in line with models of anxiety, but needs further replication. Copyright © 2014 Elsevier B.V. All rights reserved.

Interaction of threat and verbal working memory in adolescents.

PubMed

Patel, Nilam; Vytal, Katherine; Pavletic, Nevia; Stoodley, Catherine; Pine, Daniel S; Grillon, Christian; Ernst, Monique

2016-04-01

Threat induces a state of sustained anxiety that can disrupt cognitive processing, and, reciprocally, cognitive processing can modulate an anxiety response to threat. These effects depend on the level of cognitive engagement, which itself varies as a function of task difficulty. In adults, we recently showed that induced anxiety impaired working memory accuracy at low and medium but not high load. Conversely, increasing the task load reduced the physiological correlates of anxiety (anxiety-potentiated startle). The present work examines such threat-cognition interactions as a function of age. We expected threat to more strongly impact working memory in younger individuals by virtue of putatively restricted cognitive resources and weaker emotion regulation. This was tested by examining the influence of age on the interaction of anxiety and working memory in 25 adolescents (10 to 17 years) and 25 adults (22 to 46 years). Working memory load was manipulated using a verbal n-back task. Anxiety was induced using the threat of an aversive loud scream and measured via eyeblink startle. Findings revealed that, in both age groups, accuracy was lower during threat than safe conditions at low and medium but not high load, and reaction times were faster during threat than safe conditions at high load but did not differ at other loads. Additionally, anxiety-potentiated startle was greater during low and medium than high load. Thus, the interactions of anxiety with working memory appear similar in adolescents and adults. Whether these similarities reflect common neural mechanisms would need to be assessed using functional neuroimaging. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Cerebellar learning properties are modulated by the CRF receptor in granular cells.

PubMed

Ezra-Nevo, Gili; Prestori, Francesca; Locatelli, Francesca; Soda, Teresa; Ten Brinke, Michiel M; Engel, Mareen; Boele, Henk-Jan; Botta, Laura; Leshkowitz, Dena; Ramot, Assaf; Tsoory, Michael; Biton, Inbal E; Deussing, Jan; D'Angelo, Egidio; De Zeeuw, Chris I; Chen, Alon

2018-06-22

Corticotropin-releasing factor (CRF) and its type 1 receptor (CRFR 1 ) play an important role in the responses to stressful challenges. Despite the well-established expression of CRFR 1 in granular cells (GrCs), its role in procedural motor performance and memory formation remains elusive. To investigate the role of CRFR 1 expression in cerebellar GrCs, we used a mouse model depleted of CRFR 1 in these cells. We detected changes in the cellular learning mechanisms in GrCs depleted of CRFR 1 in that they showed changes in intrinsic excitability and long-term synaptic plasticity. Moreover, male mice depleted of CRFR 1 specifically in GrCs showed accelerated Pavlovian associative eye-blink conditioning, but no differences in baseline motor performance, locomotion or fear and anxiety-related behaviors. Last, we analyzed cerebella transcriptome of KO and control mice and detected prominent alterations in the expression of calcium signaling pathways components. Our findings shed light on the interplay between stress-related central mechanisms and cerebellar motor conditioning, highlighting the role of the CRF system in regulating particular forms of cerebellar learning. SIGNIFICANCE STATEMENT Although it is known that CRFR 1 is highly expressed in the cerebellum, little attention has been given to its role in cerebellar functions in the behaving animal. Moreover, most of the attention was directed to the effect of CRF on Purkinje cells at the cellular level, and to this date, almost no data exist on the role of this stress-related receptor in other cerebellar structures. Here, we explored the behavioral and cellular effect of GrCs specific ablation of CRFR 1 We found a profound effect on learning, both at the cellular and behavioral levels, without affecting baseline motor skills. Copyright © 2018 the authors.

Cost of Lightning Strike Related Outages of Visual Navigational Aids at Airports in the United States

NASA Astrophysics Data System (ADS)

Rakas, J.; Nikolic, M.; Bauranov, A.

2017-12-01

Lightning storms are a serious hazard that can cause damage to vital human infrastructure. In aviation, lightning strikes cause outages to air traffic control equipment and facilities that result in major disruptions in the network, causing delays and financial costs measured in the millions of dollars. Failure of critical systems, such as Visual Navigational Aids (Visual NAVAIDS), are particularly dangerous since NAVAIDS are an essential part of landing procedures. Precision instrument approach, an operation utilized during the poor visibility conditions, utilizes several of these systems, and their failure leads to holding patterns and ultimately diversions to other airports. These disruptions lead to both ground and airborne delay. Accurate prediction of these outages and their costs is a key prerequisite for successful investment planning. The air traffic management and control sector need accurate information to successfully plan maintenance and develop a more robust system under the threat of increasing lightning rates. To analyze the issue, we couple the Remote Monitoring and Logging System (RMLS) database and the Aviation System Performance Metrics (ASPM) databases to identify lightning-induced outages, and connect them with weather conditions, demand and landing runway to calculate the total delays induced by the outages, as well as the number of cancellations and diversions. The costs are then determined by calculating direct costs to aircraft operators and costs of passengers' time for delays, cancellations and diversions. The results indicate that 1) not all NAVAIDS are created equal, and 2) outside conditions matter. The cost of an outage depends on the importance of the failed system and the conditions that prevailed before, during and after the failure. The outage that occurs during high demand and poor weather conditions is more likely to result in more delays and higher costs.

Long-term behavioral sensitization to apomorphine is independent of conditioning and increases conditioned pecking, but not preference, in pigeons.

PubMed

Anselme, Patrick; Edeş, Neslihan; Tabrik, Sepideh; Güntürkün, Onur

2018-01-15

When rodents are given a free choice between a variable option and a constant option, they may prefer variability. This preference is even sometimes increased following repeated administration of a dopamine agonist. The present study was the first to examine preference for variability under the systemic administration of a dopamine agonist, apomorphine (Apo), in birds. Experiment 1 tested the drug-free preference and the propensity to choose of pigeons for a constant over a variable delay. It appeared that they preferred and decided more quickly to peck at the optimal delay option. Experiment 2 assessed the effects of a repeated injection of Apo on delay preference, in comparison with previous control tests within the same individuals. Apo treatment might have decreased the number of pecks at the constant option across the different experimental phases, but failed to induce a preference for the variable option. In Experiment 3, two groups of pigeons (Apo-sensitized and saline) were used in order to avoid inhomogeneity in treatments. They had to choose between a 50% probability option and a 5-s delay option. Conditioned pecking and the propensity to choose were higher in the Apo-sensitized pigeons, but, in each group, the pigeons showed indifference between the two options. This experiment also showed that long-term behavioral sensitization to Apo can occur independently of a conditioning process. These results suggest that Apo sensitization can enhance the attractiveness of conditioned cues, while having no effect on the development of a preference for variable-delay and probabilistic schedules of reinforcement. Copyright © 2017 Elsevier B.V. All rights reserved.

Why wait? Three mechanisms selecting for environment-dependent developmental delays.

PubMed

Scott, M F; Otto, S P

2014-10-01

Many species delay development unless particular environments or rare disturbance events occur. How can such a strategy be favoured over continued development? Typically, it is assumed that continued development (e.g. germination) is not advantageous in environments that have low juvenile/seedling survival (mechanism 1), either due to abiotic or competitive effects. However, it has not previously been shown how low early survival must be in order to favour environment-specific developmental delays for long-lived species. Using seed dormancy as an example of developmental delays, we identify a threshold level of seedling survival in 'bad' environments below which selection can favour germination that is limited to 'good' environments. This can be used to evaluate whether observed differences in seedling survival are sufficient to favour conditional germination. We also present mathematical models that demonstrate two other, often overlooked, mechanisms that can favour conditional germination in the absence of differences in seedling survival. Specifically, physiological trade-offs can make it difficult to have germination rates that are equally high in all environments (mechanism 2). We show that such trade-offs can either favour conditional germination or intermediate (mixed) strategies, depending on the trade-off shape. Finally, germination in every year increases the likelihood that some individuals are killed in population-scale disturbances before reproducing; it can thus be favourable to only germinate immediately after a disturbance (mechanism 3). We demonstrate how demographic data can be used to evaluate these selection pressures. By presenting these three mechanisms and the conditions that favour conditional germination in each case, we provide three hypotheses that can be tested as explanations for the evolution of environment-dependent developmental delays. © 2014 European Society for Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Delay of Gratification by Chimpanzees (Pan troglodytes) in Working and Waiting Situations

PubMed Central

Beran, Michael J.; Evans, Theodore A.

2009-01-01

We tested four chimpanzees in a self-control task in which food rewards accumulated as long as they were not eaten. In one condition, the chimpanzees had to perform a computer task that directly led to the delivery of the food rewards. In another condition, working on the computerized task was not required and any such work was not linked to the delivery of rewards. The third condition offered no computerized task (chimpanzees simply waited for food rewards to be delivered). Three of four chimpanzees showed no effect of the work scenario on delay of gratification. The one chimpanzee that showed an influence of work scenario on self-control was the overall poorest performing animal. This animal delayed gratification the longest, however, when work was required and reward delivery was directly linked to that work. Therefore, although there is little evidence linking delay of gratification to work requirements in chimpanzees, chimpanzees with lower overall self-control might benefit from having some work available if reward accumulation is contingent on performing that work. PMID:19084581

Impact of magnetic resonance imaging on ventricular tachyarrhythmia sensing: Results of the Evera MRI Study.

PubMed

Gold, Michael R; Sommer, Torsten; Schwitter, Juerg; Kanal, Emanuel; Bernabei, Matthew A; Love, Charles J; Surber, Ralf; Ramza, Brian; Cerkvenik, Jeffrey; Merkely, Béla

2016-08-01

Studies have shown that magnetic resonance imaging (MRI) conditional pacemakers experience no significant effect from MRI on device function, sensing, or pacing. More recently, similar safety outcomes were demonstrated with MRI conditional defibrillators (implantable cardioverter-defibrillator [ICD]), but the impact on ventricular arrhythmias has not been assessed. The purpose of this study was to assess the effect of MRI on ICD sensing and treatment of ventricular tachyarrhythmias. The Evera MRI Study was a worldwide trial of 156 patients implanted with an ICD designed to be MRI conditional. Device-detected spontaneous and induced ventricular tachycardia/ventricular fibrillation (VT/VF) episodes occurring before and after whole body MRI were evaluated by a blinded episode review committee. Detection delay was computed as the sum of RR intervals of undersensed beats. A ≥5-second delay in detection due to undersensing was prospectively defined as clinically significant. Post-MRI, there were 22 polymorphic VT/VF episodes in 21 patients, with 16 of these patients having 17 VT/VF episodes pre-MRI. Therapy was successful for all episodes, with no failures to treat or terminate arrhythmias. The mean detection delay due to undersensing pre- and post-MRI was 0.60 ± 0.59 and 0.33 ± 0.63 seconds, respectively (P = .17). The maximum detection delay was 2.19 seconds pre-MRI and 2.87 seconds post-MRI. Of the 17 pre-MRI episodes, 14 (82%) had some detection delay as compared with 11 of 22 (50%) post-MRI episodes (P = .03); no detection delay was clinically significant. Detection and treatment of VT/VF was excellent, with no detection delays or significant impact of MRI observed. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

A Strain-Sonde Technique for the Measurement of Mechanical Time-Delay Fuze Function Times and Performance

DTIC Science & Technology

1983-09-01

AD IV) MEMORANDUM REPORT ARBRL-MR-03309 N(Supersedes IMR No. 760) A STRAIN -SONDE TECHNIQUE FOR THE MEASUREMENT OF MECHANICAL TIME- DELAY FUZE...and BkuWel) S. TYPE OF REPORT & PERIOD COVERED A STRAIN -SONDE TECHNIQUE FOR THE MEASUREMENT OF Final MECHANICAL TIME-DELAY FUZE FUNCTION TIMES AND S...nmber) M577 Mechanical Time-Delay Fuze F"/FM Telemeter Interlock Pin Release Semiconductor Strain Gage Rotor Signal Condition Amplifier Firing Pin In

Convergence analysis of stochastic hybrid bidirectional associative memory neural networks with delays

NASA Astrophysics Data System (ADS)

Wan, Li; Zhou, Qinghua

2007-10-01

The stability property of stochastic hybrid bidirectional associate memory (BAM) neural networks with discrete delays is considered. Without assuming the symmetry of synaptic connection weights and the monotonicity and differentiability of activation functions, the delay-independent sufficient conditions to guarantee the exponential stability of the equilibrium solution for such networks are given by using the nonnegative semimartingale convergence theorem.

Global Hopf bifurcation analysis on a BAM neural network with delays

NASA Astrophysics Data System (ADS)

Sun, Chengjun; Han, Maoan; Pang, Xiaoming

2007-01-01

A delayed differential equation that models a bidirectional associative memory (BAM) neural network with four neurons is considered. By using a global Hopf bifurcation theorem for FDE and a Bendixon's criterion for high-dimensional ODE, a group of sufficient conditions for the system to have multiple periodic solutions are obtained when the sum of delays is sufficiently large.

The Effect of Delayed Responding on Stroop-Like Task Performance among Preschoolers

ERIC Educational Resources Information Center

Montgomery, Derek E.; Fosco, Whitney

2012-01-01

Forty-four preschoolers completed 2 conditions of a Stroop-like procedure (e.g., saying "boat" for car and "car" for boat) that differed in whether a 3-s delay was imposed before responding. The test card was visible during the delay period for half of the children and occluded for the other children. Preschoolers' interference control was…

The impact of physicochemical property interactions of iso -octane/ethanol blends on ignition timescales

DOE PAGES

Barraza-Botet, Cesar L.; Luecke, Jon; Zigler, Bradley T.; ...

2018-03-20

This work presents new measurements of liquid fuel ignition delay times of iso-octane and ethanol fuel blends obtained from an ignition quality tester at the National Renewable Energy Laboratory (NREL IQT), which are compared to previous ignition delay data from the University of Michigan rapid compression facility (UM RCF), at the same experimental conditions. Pressure-time histories were used to determine liquid fuel ignition delays at global stoichiometric non-premixed conditions for iso-octane, ethanol and iso-octane/ethanol blends of 25, 50, 75% by volume in mixtures of 10% oxygen diluted in nitrogen. Temperatures ranging from 880 to 970 K were studied at amore » pressure of 10 atm. By comparing total ignition delay times from the NREL IQT with chemical ignition delay times from the UM RCF, the contributions of physical phenomena were quantified as representative time scales for spray injection, breakup and evaporation processes, and for gas-phase turbulent mixing. Regression analyses were developed for ignition time scales as function of blend level and charge temperature. Non-dimensional analyses were also carried out to determine the relative effects of physical time scales with respect to chemical ignition delay times.« less

Delay and reward choice in ADHD: an experimental test of the role of delay aversion.

PubMed

Marco, Rafaela; Miranda, Ana; Schlotz, Wolff; Melia, Amanda; Mulligan, Aisling; Müller, Ueli; Andreou, Penny; Butler, Louise; Christiansen, Hanna; Gabriels, Isabel; Medad, Sheera; Albrecht, Bjorn; Uebel, Henrik; Asherson, Phillip; Banaschewski, Tobias; Gill, Michael; Kuntsi, Jonna; Mulas, Fernando; Oades, Robert; Roeyers, Herbert; Steinhausen, Hans-Christoph; Rothenberger, Aribert; Faraone, Stephen V; Sonuga-Barke, Edmund J S

2009-05-01

Children with attention deficit/hyperactivity disorder (ADHD) choose smaller sooner (SS) over larger later (LL) rewards more than controls. Here we assess the contributions of impulsive drive for immediate rewards (IDIR) and delay aversion (DAv) to this pattern. We also explore the characteristics of, and the degree of familiality in, ADHD SS responders. We had 360 ADHD probands; 349 siblings and 112 controls (aged between 6 to 17 years) chose between SS (1 point after 2 s) and LL reward (2 points after 30 s) outcomes on the Maudsley Index of Delay Aversion (Kuntsi, Oosterlaan, & Stevenson, 2001): Under one condition SS choice led to less overall trial delay under another it did not. ADHD participants chose SS more than controls under both conditions. This effect was larger when SS choice reduced trial delay. ADHD SS responders were younger, had lower IQ, more conduct disorder and had siblings who were more likely to be SS responders themselves. The results support a dual component model in which both IDIR and DAv contribute to SS choice in ADHD. SS choice may be a marker of an ADHD motivational subtype.

The impact of physicochemical property interactions of iso -octane/ethanol blends on ignition timescales

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barraza-Botet, Cesar L.; Luecke, Jon; Zigler, Bradley T.

This work presents new measurements of liquid fuel ignition delay times of iso-octane and ethanol fuel blends obtained from an ignition quality tester at the National Renewable Energy Laboratory (NREL IQT), which are compared to previous ignition delay data from the University of Michigan rapid compression facility (UM RCF), at the same experimental conditions. Pressure-time histories were used to determine liquid fuel ignition delays at global stoichiometric non-premixed conditions for iso-octane, ethanol and iso-octane/ethanol blends of 25, 50, 75% by volume in mixtures of 10% oxygen diluted in nitrogen. Temperatures ranging from 880 to 970 K were studied at amore » pressure of 10 atm. By comparing total ignition delay times from the NREL IQT with chemical ignition delay times from the UM RCF, the contributions of physical phenomena were quantified as representative time scales for spray injection, breakup and evaporation processes, and for gas-phase turbulent mixing. Regression analyses were developed for ignition time scales as function of blend level and charge temperature. Non-dimensional analyses were also carried out to determine the relative effects of physical time scales with respect to chemical ignition delay times.« less

Muscarinic receptors in amygdala control trace fear conditioning.

PubMed

Baysinger, Amber N; Kent, Brianne A; Brown, Thomas H

2012-01-01

Intelligent behavior requires transient memory, which entails the ability to retain information over short time periods. A newly-emerging hypothesis posits that endogenous persistent firing (EPF) is the neurophysiological foundation for aspects or types of transient memory. EPF is enabled by the activation of muscarinic acetylcholine receptors (mAChRs) and is triggered by suprathreshold stimulation. EPF occurs in several brain regions, including the lateral amygdala (LA). The present study examined the role of amygdalar mAChRs in trace fear conditioning, a paradigm that requires transient memory. If mAChR-dependent EPF selectively supports transient memory, then blocking amygdalar mAChRs should impair trace conditioning, while sparing delay and context conditioning, which presumably do not rely upon transient memory. To test the EPF hypothesis, LA was bilaterally infused, prior to trace or delay conditioning, with either a mAChR antagonist (scopolamine) or saline. Computerized video analysis quantified the amount of freezing elicited by the cue and by the training context. Scopolamine infusion profoundly reduced freezing in the trace conditioning group but had no significant effect on delay or context conditioning. This pattern of results was uniquely anticipated by the EPF hypothesis. The present findings are discussed in terms of a systems-level theory of how EPF in LA and several other brain regions might help support trace fear conditioning.

Token reinforcement, choice, and self-control in pigeons.

PubMed Central

Jackson, K; Hackenberg, T D

1996-01-01

Pigeons were exposed to self-control procedures that involved illumination of light-emitting diodes (LEDs) as a form of token reinforcement. In a discrete-trials arrangement, subjects chose between one and three LEDs; each LED was exchangeable for 2-s access to food during distinct posttrial exchange periods. In Experiment 1, subjects generally preferred the immediate presentation of a single LED over the delayed presentation of three LEDs, but differences in the delay to the exchange period between the two options prevented a clear assessment of the relative influence of LED delay and exchange-period delay as determinants of choice. In Experiment 2, in which delays to the exchange period from either alternative were equal in most conditions, all subjects preferred the delayed three LEDs more often than in Experiment-1. In Experiment 3, subjects preferred the option that resulted in a greater amount of food more often if the choices also produced LEDs than if they did not. In Experiment 4, preference for the delayed three LEDs was obtained when delays to the exchange period were equal, but reversed in favor of an immediate single LED when the latter choice also resulted in quicker access to exchange periods. The overall pattern of results suggests that (a) delay to the exchange period is a more critical determinant of choice than is delay to token presentation; (b) tokens may function as conditioned reinforcers, although their discriminative properties may be responsible for the self-control that occurs under token reinforcer arrangements; and (c) previously reported differences in the self-control choices of humans and pigeons may have resulted at least in part from the procedural conventions of using token reinforcers with human subjects and food reinforcers with pigeon subjects. PMID:8755699

Efficacy of maternal choline supplementation during pregnancy in mitigating adverse effects of prenatal alcohol exposure on growth and cognitive function: A randomized, double-blind, placebo-controlled clinical trial.

PubMed

Jacobson, Sandra W; Carter, R Colin; Molteno, Christopher D; Stanton, Mark E; Herbert, Jane; Lindinger, Nadine M; Lewis, Catherine E; Dodge, Neil C; Hoyme, H Eugene; Zeisel, Steven H; Meintjes, Ernesta M; Duggan, Christopher P; Jacobson, Joseph L

2018-05-11

We recently demonstrated the acceptability and feasibility of a randomized, double-blind choline supplementation intervention for heavy drinking women during pregnancy. In this paper, we report our results relating to the efficacy of this intervention in mitigating adverse effects of prenatal alcohol exposure on infant growth and cognitive function. 69 Cape Coloured (mixed ancestry) heavy drinkers in Cape Town, South Africa, recruited in mid-pregnancy, were randomly assigned to receive a daily oral dose of either 2 g of choline or placebo from time of enrollment until delivery. Each dose consisted of an individually wrapped packet of powder that, when mixed with water, produced a sweet tasting grape-flavored drink. The primary outcome, eyeblink conditioning (EBC), was assessed at 6.5 months. Somatic growth was measured at birth, 6.5, and 12 months; recognition memory and processing speed on the Fagan Test of Infant Intelligence, at 6.5 and 12 months. Infants born to choline-treated mothers were more likely to meet criterion for conditioning on EBC than the placebo group. Moreover, within the choline arm, degree of maternal adherence to the supplementation protocol strongly predicted EBC performance. Both groups were small at birth, but choline-treated infants showed considerable catch-up growth in weight and head circumference at 6.5 and 12 months. At 12 months, the infants in the choline treatment arm had higher novelty preference scores, indicating better visual recognition memory. This exploratory study is the first to provide evidence that a high dose of choline administered early in pregnancy can mitigate adverse effects of heavy prenatal alcohol exposure on EBC, postnatal growth, and cognition in human infants. These findings are consistent with studies of alcohol-exposed animals that have demonstrated beneficial effects of choline supplementation on classical conditioning, learning, and memory. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Coordinated Parallel Runway Approaches

NASA Technical Reports Server (NTRS)

Koczo, Steve

1996-01-01

The current air traffic environment in airport terminal areas experiences substantial delays when weather conditions deteriorate to Instrument Meteorological Conditions (IMC). Expected future increases in air traffic will put additional pressures on the National Airspace System (NAS) and will further compound the high costs associated with airport delays. To address this problem, NASA has embarked on a program to address Terminal Area Productivity (TAP). The goals of the TAP program are to provide increased efficiencies in air traffic during the approach, landing, and surface operations in low-visibility conditions. The ultimate goal is to achieve efficiencies of terminal area flight operations commensurate with Visual Meteorological Conditions (VMC) at current or improved levels of safety.

An experimental and modeling study investigating the ignition delay in a military diesel engine running hexadecane (cetane) fuel

DOE PAGES

Cowart, Jim S.; Fischer, Warren P.; Hamilton, Leonard J.; ...

2013-02-01

In an effort aimed at predicting the combustion behavior of a new fuel in a conventional diesel engine, cetane (n-hexadecane) fuel was used in a military engine across the entire speed–load operating range. The ignition delay was characterized for this fuel at each operating condition. A chemical ignition delay was also predicted across the speed–load range using a detailed chemical kinetic mechanism with a constant pressure reactor model. At each operating condition, the measured in-cylinder pressure and predicted temperature at the start of injection were applied to the detailed n-hexadecane kinetic mechanism, and the chemical ignition delay was predicted withoutmore » any kinetic mechanism calibration. The modeling results show that fuel–air parcels developed from the diesel spray with an equivalence ratio of 4 are the first to ignite. The chemical ignition delay results also showed decreasing igntion delays with increasing engine load and speed, just as the experimental data revealed. At lower engine speeds and loads, the kinetic modeling results show the characteristic two-stage negative temperature coefficient behavior of hydrocarbon fuels. However, at high engine speeds and loads, the reactions do not display negative temperature coefficient behavior, as the reactions proceed directly into high-temperature pathways due to higher temperatures and pressure at injection. A moderate difference between the total and chemical ignition delays was then characterized as a phyical delay period that scales inversely with engine speed. This physical delay time is representative of the diesel spray development time and is seen to become a minority fraction of the total igntion delay at higher engine speeds. In addition, the approach used in this study suggests that the ignition delay and thus start of combustion may be predicted with reasonable accuracy using kinetic modeling to determine the chemical igntion delay. Then, in conjunction with the physical delay time (experimental or modeling based), a new fuel’s acceptability in a conventional engine could be assessed by determining that the total ignition delay is not too short or too long.« less

Mode Selection Rules for a Two-Delay System with Positive and Negative Feedback Loops

NASA Astrophysics Data System (ADS)

Takahashi, Kin'ya; Kobayashi, Taizo

2018-04-01

The mode selection rules for a two-delay system, which has negative feedback with a short delay time t1 and positive feedback with a long delay time t2, are studied numerically and theoretically. We find two types of mode selection rules depending on the strength of the negative feedback. When the strength of the negative feedback |α1| (α1 < 0) is sufficiently small compared with that of the positive feedback α2 (> 0), 2m + 1-th harmonic oscillation is well sustained in a neighborhood of t1/t2 = even/odd, i.e., relevant condition. In a neighborhood of the irrelevant condition given by t1/t2 = odd/even or t1/t2 = odd/odd, higher harmonic oscillations are observed. However, if |α1| is slightly less than α2, a different mode selection rule works, where the condition t1/t2 = odd/even is relevant and the conditions t1/t2 = odd/odd and t1/t2 = even/odd are irrelevant. These mode selection rules are different from the mode selection rule of the normal two-delay system with two positive feedback loops, where t1/t2 = odd/odd is relevant and the others are irrelevant. The two types of mode selection rules are induced by individually different mechanisms controlling the Hopf bifurcation, i.e., the Hopf bifurcation controlled by the "boosted bifurcation process" and by the "anomalous bifurcation process", which occur for |α1| below and above the threshold value αth, respectively.

Synchronization of fractional-order complex-valued neural networks with time delay.

PubMed

Bao, Haibo; Park, Ju H; Cao, Jinde

2016-09-01

This paper deals with the problem of synchronization of fractional-order complex-valued neural networks with time delays. By means of linear delay feedback control and a fractional-order inequality, sufficient conditions are obtained to guarantee the synchronization of the drive-response systems. Numerical simulations are provided to show the effectiveness of the obtained results. Copyright © 2016 Elsevier Ltd. All rights reserved.

Delayed Matching to Sample: Probability of Responding in Accord with Equivalence as a Function of Different Delays

ERIC Educational Resources Information Center

Arntzen, Erik

2006-01-01

The present series of 4 experiments investigated the probability of responding in accord with equivalence in adult human participants as a function of increasing or decreasing delays in a many-to-one (MTO) or comparison-as-node and one-to-many (OTM) or sample-as-node conditional discrimination procedure. In Experiment 1, 12 participants started…

A Longitudinal Investigation of Conflict and Delay Inhibitory Control in Toddlers and Preschoolers

ERIC Educational Resources Information Center

Joyce, Amanda W.; Kraybill, Jessica H.; Chen, Nan; Cuevas, Kimberly; Deater-Deckard, Kirby; Bell, Martha Ann

2016-01-01

Research Findings: A total of 81 children participated in a longitudinal investigation of inhibitory control (IC) from 2 to 4 years of age. Child IC was measured via maternal report and laboratory measures under conditions of conflict and delay. Performance on delay IC tasks at 3 years was related to performance on these same tasks at 2 and…

Synchronization stability of memristor-based complex-valued neural networks with time delays.

PubMed

Liu, Dan; Zhu, Song; Ye, Er

2017-12-01

This paper focuses on the dynamical property of a class of memristor-based complex-valued neural networks (MCVNNs) with time delays. By constructing the appropriate Lyapunov functional and utilizing the inequality technique, sufficient conditions are proposed to guarantee exponential synchronization of the coupled systems based on drive-response concept. The proposed results are very easy to verify, and they also extend some previous related works on memristor-based real-valued neural networks. Meanwhile, the obtained sufficient conditions of this paper may be conducive to qualitative analysis of some complex-valued nonlinear delayed systems. A numerical example is given to demonstrate the effectiveness of our theoretical results. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impulsive synchronization of stochastic reaction-diffusion neural networks with mixed time delays.

PubMed

Sheng, Yin; Zeng, Zhigang

2018-07-01

This paper discusses impulsive synchronization of stochastic reaction-diffusion neural networks with Dirichlet boundary conditions and hybrid time delays. By virtue of inequality techniques, theories of stochastic analysis, linear matrix inequalities, and the contradiction method, sufficient criteria are proposed to ensure exponential synchronization of the addressed stochastic reaction-diffusion neural networks with mixed time delays via a designed impulsive controller. Compared with some recent studies, the neural network models herein are more general, some restrictions are relaxed, and the obtained conditions enhance and generalize some published ones. Finally, two numerical simulations are performed to substantiate the validity and merits of the developed theoretical analysis. Copyright © 2018 Elsevier Ltd. All rights reserved.

Rank One Strange Attractors in Periodically Kicked Predator-Prey System with Time-Delay

NASA Astrophysics Data System (ADS)

Yang, Wenjie; Lin, Yiping; Dai, Yunxian; Zhao, Huitao

2016-06-01

This paper is devoted to the study of the problem of rank one strange attractor in a periodically kicked predator-prey system with time-delay. Our discussion is based on the theory of rank one maps formulated by Wang and Young. Firstly, we develop the rank one chaotic theory to delayed systems. It is shown that strange attractors occur when the delayed system undergoes a Hopf bifurcation and encounters an external periodic force. Then we use the theory to the periodically kicked predator-prey system with delay, deriving the conditions for Hopf bifurcation and rank one chaos along with the results of numerical simulations.

Extinguishing trace fear engages the retrosplenial cortex rather than the amygdala

PubMed Central

Kwapis, Janine L.; Jarome, Timothy J.; Lee, Jonathan L.; Gilmartin, Marieke R.; Helmstetter, Fred J.

2013-01-01

Extinction learning underlies the treatment for a variety of anxiety disorders. Most of what is known about the neurobiology of extinction is based on standard “delay” fear conditioning, in which awareness is not required for learning. Little is known about how complex, explicit associations extinguish, however. “Trace” conditioning is considered to be a rodent model of explicit fear because it relies on both the cortex and hippocampus and requires explicit contingency awareness in humans. Here, we explore the neural circuit supporting trace fear extinction in order to better understand how complex memories extinguish. We first show that the amygdala is selectively involved in delay fear extinction; blocking intra-amygdala glutamate receptors disrupted delay, but not trace extinction. Further, ERK phosphorylation was increased in the amygdala after delay, but not trace extinction. We then identify the retrosplenial cortex (RSC) as a key structure supporting trace extinction. ERK phosphorylation was selectively increased in the RSC following trace extinction and blocking intra-RSC NMDA receptors impaired trace, but not delay extinction. These findings indicate that delay and trace extinction require different neural circuits; delay extinction requires plasticity in the amygdala whereas trace extinction requires the RSC. Anxiety disorders linked to explicit memory may therefore depend on cortical processes that have not been traditionally targeted by extinction studies based on delay fear. PMID:24055593

Signals, resistance to change, and conditioned reinforcement in a multiple schedule.

PubMed

Bell, Matthew C; Gomez, Belen E; Kessler, Kira

2008-06-01

The effect of signals on resistance to change was evaluated using pigeons responding on a three-component multiple schedule. Each component contained a variable-interval initial link followed by a fixed-time terminal link. One component was an unsignaled-delay schedule, and two were equivalent signaled-delay schedules. After baseline training, resistance to change was assessed through (a) extinction and (b) adding free food to the intercomponent interval. During these tests, the signal stimulus from one of the signaled-delay components (SIG-T) was replaced with the initial-link stimulus from that component, converting it to an unsignaled-delay schedule. That signal stimulus was added to the delay period of the unsignaled-delay component (UNS), converting it to a signaled-delay schedule. The remaining signaled component remained unchanged (SIG-C). Resistance-to-change tests showed removing the signal had a minimal effect on resistance to change in the SIG-T component compared to the unchanged SIG-C component except for one block during free-food testing. Adding the signal to the UNS component significantly increased response rates suggesting that component had low response strength. Interestingly, the direction of the effect was in the opposite direction from what is typically observed. Results are consistent with the conclusion that the signal functioned as a conditioned reinforcer and inconsistent with a generalization-decrement explanation.

Finite-time resilient decentralized control for interconnected impulsive switched systems with neutral delay.

PubMed

Ren, Hangli; Zong, Guangdeng; Hou, Linlin; Yang, Yi

2017-03-01

This paper is concerned with the problem of finite-time control for a class of interconnected impulsive switched systems with neutral delay in which the time-varying delay appears in both the state and the state derivative. The concepts of finite-time boundedness and finite-time stability are respectively extended to interconnected impulsive switched systems with neutral delay for the first time. By applying the average dwell time method, sufficient conditions are first derived to cope with the problem of finite-time boundedness and finite-time stability for interconnected impulsive switched systems with neutral delay. In addition, the purpose of finite-time resilient decentralized control is to construct a resilient decentralized state-feedback controller such that the closed-loop system is finite-time bounded and finite-time stable. All the conditions are formulated in terms of linear matrix inequalities to ensure finite-time boundedness and finite-time stability of the given system. Finally, an example is presented to illustrate the effectiveness of the proposed approach. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Cingulo-opercular activity affects incidental memory encoding for speech in noise.

PubMed

Vaden, Kenneth I; Teubner-Rhodes, Susan; Ahlstrom, Jayne B; Dubno, Judy R; Eckert, Mark A

2017-08-15

Correctly understood speech in difficult listening conditions is often difficult to remember. A long-standing hypothesis for this observation is that the engagement of cognitive resources to aid speech understanding can limit resources available for memory encoding. This hypothesis is consistent with evidence that speech presented in difficult conditions typically elicits greater activity throughout cingulo-opercular regions of frontal cortex that are proposed to optimize task performance through adaptive control of behavior and tonic attention. However, successful memory encoding of items for delayed recognition memory tasks is consistently associated with increased cingulo-opercular activity when perceptual difficulty is minimized. The current study used a delayed recognition memory task to test competing predictions that memory encoding for words is enhanced or limited by the engagement of cingulo-opercular activity during challenging listening conditions. An fMRI experiment was conducted with twenty healthy adult participants who performed a word identification in noise task that was immediately followed by a delayed recognition memory task. Consistent with previous findings, word identification trials in the poorer signal-to-noise ratio condition were associated with increased cingulo-opercular activity and poorer recognition memory scores on average. However, cingulo-opercular activity decreased for correctly identified words in noise that were not recognized in the delayed memory test. These results suggest that memory encoding in difficult listening conditions is poorer when elevated cingulo-opercular activity is not sustained. Although increased attention to speech when presented in difficult conditions may detract from more active forms of memory maintenance (e.g., sub-vocal rehearsal), we conclude that task performance monitoring and/or elevated tonic attention supports incidental memory encoding in challenging listening conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

Delayed nonlinear cournot and bertrand dynamics with product differentiation.

PubMed

Matsumoto, Akio; Szidarovszky, Ferenc

2007-07-01

Dynamic duopolies will be examined with product differentiation and isoelastic price functions. We will first prove that under realistic conditions the equilibrium is always locally asymptotically stable. The stability can however be lost if the firms use delayed information in forming their best responses. Stability conditions are derived in special cases, and simulation results illustrate the complexity of the dynamism of the systems. Both price and quantity adjusting models are discussed.

Dwell time-based stabilisation of switched delay systems using free-weighting matrices

NASA Astrophysics Data System (ADS)

Koru, Ahmet Taha; Delibaşı, Akın; Özbay, Hitay

2018-01-01

In this paper, we present a quasi-convex optimisation method to minimise an upper bound of the dwell time for stability of switched delay systems. Piecewise Lyapunov-Krasovskii functionals are introduced and the upper bound for the derivative of Lyapunov functionals is estimated by free-weighting matrices method to investigate non-switching stability of each candidate subsystems. Then, a sufficient condition for the dwell time is derived to guarantee the asymptotic stability of the switched delay system. Once these conditions are represented by a set of linear matrix inequalities , dwell time optimisation problem can be formulated as a standard quasi-convex optimisation problem. Numerical examples are given to illustrate the improvements over previously obtained dwell time bounds. Using the results obtained in the stability case, we present a nonlinear minimisation algorithm to synthesise the dwell time minimiser controllers. The algorithm solves the problem with successive linearisation of nonlinear conditions.

Developmental delay

USDA-ARS?s Scientific Manuscript database

Nutrition support is essential for the care of the child with developmental delay. After a thorough evaluation, an individualized intervention plan that accounts for the child’s nutrition status, feeding ability, and medical condition may be determined. Nutrition assessments may be performed at leas...

The absence or temporal offset of visual feedback does not influence adaptation to novel movement dynamics.

PubMed

McKenna, Erin; Bray, Laurence C Jayet; Zhou, Weiwei; Joiner, Wilsaan M

2017-10-01

Delays in transmitting and processing sensory information require correctly associating delayed feedback to issued motor commands for accurate error compensation. The flexibility of this alignment between motor signals and feedback has been demonstrated for movement recalibration to visual manipulations, but the alignment dependence for adapting movement dynamics is largely unknown. Here we examined the effect of visual feedback manipulations on force-field adaptation. Three subject groups used a manipulandum while experiencing a lag in the corresponding cursor motion (0, 75, or 150 ms). When the offset was applied at the start of the session (continuous condition), adaptation was not significantly different between groups. However, these similarities may be due to acclimation to the offset before motor adaptation. We tested additional subjects who experienced the same delays concurrent with the introduction of the perturbation (abrupt condition). In this case adaptation was statistically indistinguishable from the continuous condition, indicating that acclimation to feedback delay was not a factor. In addition, end-point errors were not significantly different across the delay or onset conditions, but end-point correction (e.g., deceleration duration) was influenced by the temporal offset. As an additional control, we tested a group of subjects who performed without visual feedback and found comparable movement adaptation results. These results suggest that visual feedback manipulation (absence or temporal misalignment) does not affect adaptation to novel dynamics, independent of both acclimation and perceptual awareness. These findings could have implications for modeling how the motor system adjusts to errors despite concurrent delays in sensory feedback information. NEW & NOTEWORTHY A temporal offset between movement and distorted visual feedback (e.g., visuomotor rotation) influences the subsequent motor recalibration, but the effects of this offset for altered movement dynamics are largely unknown. Here we examined the influence of 1 ) delayed and 2 ) removed visual feedback on the adaptation to novel movement dynamics. These results contribute to understanding of the control strategies that compensate for movement errors when there is a temporal separation between motion state and sensory information. Copyright © 2017 the American Physiological Society.

Let it go: the flexible engagement and disengagement of monitoring processes in a non-focal prospective memory task.

PubMed

Cohen, Anna-Lisa; Gordon, Aliza; Jaudas, Alexander; Hefer, Carmen; Dreisbach, Gesine

2017-03-01

Remembering to perform a delayed intention is referred to as prospective memory (PM). In two studies, participants performed an Eriksen flanker task with an embedded PM task (they had to remember to press F1 if a pre-specified cue appeared). In study 1, participants performed a flanker task with either a concurrent PM task or a delayed PM task (instructed to carry out the intention in a later different task). In the delayed PM condition, the PM cues appeared unexpectedly early and we examined whether attention would be captured by the PM cue even though they were not relevant. Results revealed ongoing task costs solely in the concurrent PM condition but no significant task costs in the delayed PM condition showing that attention was not captured by the PM cue when it appeared in an irrelevant context. In study 2, we compared a concurrent PM condition (exactly as in Study 1) to a PM forget condition in which participants were told at a certain point during the flanker task that they no longer had to perform the PM task. Analyses revealed that participants were able to switch off attending to PM cues when instructed to forget the PM task. Results from both studies demonstrate the flexibility of monitoring as evidenced by the presence versus absence of costs in the ongoing flanker task implying that selective attention, like a lens, can be adjusted to attend or ignore, depending on intention relevance.

Discrete-time bidirectional associative memory neural networks with variable delays

NASA Astrophysics Data System (ADS)

Liang, variable delays [rapid communication] J.; Cao, J.; Ho, D. W. C.

2005-02-01

Based on the linear matrix inequality (LMI), some sufficient conditions are presented in this Letter for the existence, uniqueness and global exponential stability of the equilibrium point of discrete-time bidirectional associative memory (BAM) neural networks with variable delays. Some of the stability criteria obtained in this Letter are delay-dependent, and some of them are delay-independent, they are less conservative than the ones reported so far in the literature. Furthermore, the results provide one more set of easily verified criteria for determining the exponential stability of discrete-time BAM neural networks.

Optical stabilization for time transfer infrastructure

NASA Astrophysics Data System (ADS)

Vojtech, Josef; Altmann, Michal; Skoda, Pavel; Horvath, Tomas; Slapak, Martin; Smotlacha, Vladimir; Havlis, Ondrej; Munster, Petr; Radil, Jan; Kundrat, Jan; Altmannova, Lada; Velc, Radek; Hula, Miloslav; Vohnout, Rudolf

2017-08-01

In this paper, we propose and present verification of all-optical methods for stabilization of the end-to-end delay of an optical fiber link. These methods are verified for deployment within infrastructure for accurate time and stable frequency distribution, based on sharing of fibers with research and educational network carrying live data traffic. Methods range from path length control, through temperature conditioning method to transmit wavelength control. Attention is given to achieve continuous control for relatively broad range of delays. We summarize design rules for delay stabilization based on the character and the total delay jitter.

Group consensus control for networked multi-agent systems with communication delays.

PubMed

An, Bao-Ran; Liu, Guo-Ping; Tan, Chong

2018-05-01

This paper investigates group consensus problems in networked multi-agent systems (NMAS) with communication delays. Based on the sed state prediction scheme, the group consensus control protocol is designed to compensate the communication delay actively. In light of algebraic graph theories and matrix theories, necessary and(or) sufficient conditions of group consensus with respect to a given admissible control set are obtained for the NMAS with communication delays under mild assumptions. Finally, simulations are performed to demonstrate the effectiveness of the theoretical results. Copyright © 2018 ISA. All rights reserved.

Synchronization and anti-synchronization of a fractional order delayed memristor-based chaotic system using active control

NASA Astrophysics Data System (ADS)

Ding, Dawei; Qian, Xin; Wang, Nian; Liang, Dong

2018-05-01

In this paper, the issue of synchronization and anti-synchronization for fractional-delayed memristor-based chaotic system is studied by using active control strategy. Firstly, some explicit conditions are proposed to guarantee the synchronization and anti-synchronization of the proposed system. Secondly, the influence of order and time delay on the synchronization (anti-synchronization) is discussed. It reveals that synchronization (anti-synchronization) is faster as the order increases or the time delay decreases. Finally, some numerical simulations are presented to verify the validity of our theoretical analysis.

Angular Distributions of Discrete Mesoscale Mapping Functions

NASA Astrophysics Data System (ADS)

Kroszczyński, Krzysztof

2015-08-01

The paper presents the results of analyses of numerical experiments concerning GPS signal propagation delays in the atmosphere and the discrete mapping functions defined on their basis. The delays were determined using data from the mesoscale non-hydrostatic weather model operated in the Centre of Applied Geomatics, Military University of Technology. A special attention was paid to investigating angular characteristics of GPS slant delays for low angles of elevation. The investigation proved that the temporal and spatial variability of the slant delays depends to a large extent on current weather conditions.

Discounting of Condom-Protected Sex as a Measure of High Risk for Sexually Transmitted Infection Among College Students.

PubMed

Collado, Anahí; Johnson, Patrick S; Loya, Jennifer M; Johnson, Matthew W; Yi, Richard

2017-10-01

The study examined sexual delay discounting, or the devaluation of condom-protected sex in the face of delay, as a risk factor for sexually transmitted infection (STI) among college students. Participants (143 females, 117 males) completed the sexual delay discounting task (Johnson & Bruner, 2012) and questionnaires of risky sexual behavior, risk perception, and knowledge. Participants exhibited steeper sexual delay discounting (above and beyond general likelihood of having unprotected sex) when partners were viewed as more desirable or less likely to have a STI, with males demonstrating greater sexual delay discounting than females across most conditions. Importantly, greater self-reported risky sexual behaviors were associated with higher rates of sexual delay discounting, but not with likelihood of using a condom in the absence of delay. These results provide support for considering sexual delay discounting, with particular emphasis on potential delays to condom use, as a risk factor for STI among college students.

When good pigeons make bad decisions: Choice with probabilistic delays and outcomes.

PubMed

Pisklak, Jeffrey M; McDevitt, Margaret A; Dunn, Roger M; Spetch, Marcia L

2015-11-01

Pigeons chose between an (optimal) alternative that sometimes provided food after a 10-s delay and other times after a 40-s delay and another (suboptimal) alternative that sometimes provided food after 10 s but other times no food after 40 s. When outcomes were not signaled during the delays, pigeons strongly preferred the optimal alternative. When outcomes were signaled, choices of the suboptimal alternative increased and most pigeons preferred the alternative that provided no food after the long delay despite the cost in terms of obtained food. The pattern of results was similar whether the short delays occurred on 25% or 50% of the trials. Shortening the 40-s delay to food sharply reduced suboptimal choices, but shortening the delay to no food had little effect. The results suggest that a signaled delay to no food does not punish responding in probabilistic choice procedures. The findings are discussed in terms of conditioned reinforcement by signals for good news. © Society for the Experimental Analysis of Behavior.

National Airspace System Delay Estimation Using Weather Weighted Traffic Counts

NASA Technical Reports Server (NTRS)

Chatterji, Gano B.; Sridhar, Banavar

2004-01-01

Assessment of National Airspace System performance, which is usually measured in terms of delays resulting from the application of traffic flow management initiatives in response to weather conditions, volume, equipment outages and runway conditions, is needed both for guiding flow control decisions during the day of operations and for post operations analysis. Comparison of the actual delay, resulting from the traffic flow management initiatives, with the expected delay, based on traffic demand and other conditions, provides the assessment of the National Airspace System performance. This paper provides a method for estimating delay using the expected traffic demand and weather. In order to identify the cause of delays, 517 days of National Airspace System delay data reported by the Federal Aviation Administration s Operations Network were analyzed. This analysis shows that weather is the most important causal factor for delays followed by equipment and runway delays. Guided by these results, the concept of weather weighted traffic counts as a measure of system delay is described. Examples are given to show the variation of these counts as a function of time of the day. The various datasets, consisting of aircraft position data, enroute severe weather data, surface wind speed and visibility data, reported delay data and number of aircraft handled by the Centers data, and their sources are described. The procedure for selecting reference days on which traffic was minimally impacted by weather is described. Different traffic demand on each reference day of the week, determined by analysis of 42 days of traffic and delay data, was used as the expected traffic demand for each day of the week. Next, the method for computing the weather weighted traffic counts using the expected traffic demand, derived from reference days, and the expanded regions around severe weather cells is discussed. It is shown via a numerical example that this approach improves the dynamic range of the weather weighted traffic counts considerably. Time histories of these new weather weighted traffic counts are used for synthesizing two statistical features, six histogram features and six time domain features. In addition to these enroute weather features, two surface weather features of number of major airports in the United States with high mean winds and low mean visibility are also described. A least squares procedure for establishing a functional relation between the features, using combinations of these features, and system delays is explored using 36 days of data. Best correlations between the estimated delays using the functional relation and the actual delays provided by the Operations Network are obtained with two different combinations of features: 1) six time domain features of weather weighted traffic counts plus two surface weather features, and 2) six histogram features and mean of weather weighted traffic counts along with the two surface weather features. Correlation coefficient values of 0.73 and 0.83 were found in these two instances.

The effects of adults' affective expression and direction of visual gaze on 12-month-olds' visual preferences for an object following a 5-minute, 1-day, or 1-month delay.

PubMed

Flom, Ross; Johnson, Sarah

2011-03-01

Between 12- and 14 months of age infants begin to use another's direction of gaze and affective expression in learning about various objects and events. What is not well understood is how long infants' behaviour towards a previously unfamiliar object continues to be influenced following their participation in circumstances of social referencing. In this experiment, we examined infants' sensitivity to an adult's direction of gaze and their visual preference for one of two objects following a 5-min, 1-day, or 1-month delay. Ninety-six 12-month-olds participated. For half of the infants during habituation (i.e., familiarization), the adults' direction of gaze was directed towards an unfamiliar object (look condition). For the remaining half of the infants during habituation, the adults' direction of gaze was directed away from the unfamiliar object (look-away condition). All infants were habituated to two events. One event consisted of an adult looking towards (look condition) or away from (look-away condition) an object while facially and vocally conveying a positive affective expression. The second event consisted of the same adult looking towards or away from a different object while conveying a disgusted affective expression. Following the habituation phase and a 5-min, 1-day, or 1-month delay, infants' visual preference was assessed. During the visual preference phase, infants saw the two objects side by side where the adult conveying the affective expression was not visible. Results of the visual preference phase indicate that infants in the look condition showed a significant preference for object previously paired with the positive affect following a 5-min and 1-day delay. No significant visual preference was found in the look condition following a 1-month delay. No significant preferences were found at any retention interval in the look-away condition. Results are discussed in terms of early learning, social referencing, and early memory. ©2010 The British Psychological Society.

A NMDA Receptor Antagonist, MK-801 Impairs Consolidating Extinction of Auditory Conditioned Fear Responses in a Pavlovian Model

PubMed Central

Wang, Zheng-Hong; Rao, Zhi-Ren; Wu, Sheng-Xi; Li, Yun-Qing; Wang, Wen

2009-01-01

Background In auditory fear conditioning, repeated presentation of the tone in the absence of shock leads to extinction of the acquired fear responses. The glutamate N-methyl-D-aspartate receptor (NMDAR) is thought to be involved in the extinction of the conditioned fear responses, but its detailed role in initiating and consolidating or maintaining the fear extinction memory is unclear. Here we investigated this issue by using a NMDAR antagonist, MK-801. Methods/Main Findings The effects of immediate (beginning at 10 min after the conditioning) and delayed (beginning at 24 h after conditioning) extinctions were first compared with the finding that delayed extinction caused a better and long-lasting (still significant on the 20th day after extinction) depression on the conditioned fear responses. In a second experiment, MK-801 was intraperitoneally (i.p.) injected at 40 min before, 4 h or 12 h after the delayed extinction, corresponding to critical time points for initiating, consolidating or maintaining the fear extinction memory. i.p. injection of MK-801 at either 40 min before or 4 h after delayed extinction resulted in an impairment of initiating and consolidating fear extinction memory, which caused a long lasting increased freezing score that was still significant on the 7th day after extinction, compared with extinction group. However, MK-801 administered at 12 h after the delayed extinction, when robust consolidation has been occurred and stabilized, did not affect the established extinction memory. Furthermore, the changed freezing behaviors was not due to an alteration in general anxiety levels, since MK-801 treatment had no effect on the percentage of open-arm time or open-arm entries in an Elevated Plus Maze (EPM) task. Conclusions/Significance Our data suggested that the activation of NMDARs plays important role in initiation and consolidation but not maintenance of fear extinction memory. Together with the fact that NMDA receptor is very important for memory, our data added experimental evidence to the concept that the extinction of conditioned fear responses is a procedure of initiating and consolidating new memory other than simply “erasing” the fear memory. PMID:19855841

A NMDA receptor antagonist, MK-801 impairs consolidating extinction of auditory conditioned fear responses in a Pavlovian model.

PubMed

Liu, Jun-Li; Li, Min; Dang, Xiao-Rong; Wang, Zheng-Hong; Rao, Zhi-Ren; Wu, Sheng-Xi; Li, Yun-Qing; Wang, Wen

2009-10-26

In auditory fear conditioning, repeated presentation of the tone in the absence of shock leads to extinction of the acquired fear responses. The glutamate N-methyl-D-aspartate receptor (NMDAR) is thought to be involved in the extinction of the conditioned fear responses, but its detailed role in initiating and consolidating or maintaining the fear extinction memory is unclear. Here we investigated this issue by using a NMDAR antagonist, MK-801. The effects of immediate (beginning at 10 min after the conditioning) and delayed (beginning at 24 h after conditioning) extinctions were first compared with the finding that delayed extinction caused a better and long-lasting (still significant on the 20(th) day after extinction) depression on the conditioned fear responses. In a second experiment, MK-801 was intraperitoneally (i.p.) injected at 40 min before, 4 h or 12 h after the delayed extinction, corresponding to critical time points for initiating, consolidating or maintaining the fear extinction memory. i.p. injection of MK-801 at either 40 min before or 4 h after delayed extinction resulted in an impairment of initiating and consolidating fear extinction memory, which caused a long lasting increased freezing score that was still significant on the 7th day after extinction, compared with extinction group. However, MK-801 administered at 12 h after the delayed extinction, when robust consolidation has been occurred and stabilized, did not affect the established extinction memory. Furthermore, the changed freezing behaviors was not due to an alteration in general anxiety levels, since MK-801 treatment had no effect on the percentage of open-arm time or open-arm entries in an Elevated Plus Maze (EPM) task. Our data suggested that the activation of NMDARs plays important role in initiation and consolidation but not maintenance of fear extinction memory. Together with the fact that NMDA receptor is very important for memory, our data added experimental evidence to the concept that the extinction of conditioned fear responses is a procedure of initiating and consolidating new memory other than simply "erasing" the fear memory.

The Effect of Brief Delays to Reinforcement on the Acquisition of Tacts in Children with Autism

ERIC Educational Resources Information Center

Majdalany, Lina; Wilder, David A.; Smeltz, Lindsay; Lipschultz, Joshua

2016-01-01

We used discrete-trial training to teach 3 children with autism to tact shapes of countries using 3 levels of reinforcement delay for correct responding: 0 s (immediate delivery), 6 s, and 12 s. Two of the 3 participants acquired the targets more quickly in the immediate-delivery condition, suggesting that delays as brief as 6 s may be detrimental…

Reward type and behavioural patterns predict dogs’ success in a delay of gratification paradigm

PubMed Central

Brucks, Désirée; Soliani, Matteo; Range, Friederike; Marshall-Pescini, Sarah

2017-01-01

Inhibiting an immediate behaviour in favour of an alternative but more advantageous behaviour has been linked to individual success in life, especially in humans. Dogs, which have been living in the human environment for thousands of years, are exposed to daily situations that require inhibition different in context from other non-domesticated species. One task regularly used to study inhibitory control is the delay of gratification task, which requires individuals to choose between an immediate option of lower value and a delayed option of higher value. We tested sixteen dogs in a non-social delay of gratification task, conducting two different conditions: a quality and a quantity condition. While the majority of dogs failed to wait for more than 10 s, some dogs tolerated delays of up to 140 s, while one dog waited for 15 minutes. Moreover, dogs had more difficulties to wait if the reward increased in terms of quantity than quality. Interestingly, dogs were able to anticipate the delay duration and some dogs developed behavioural patterns that predicted waiting, which seems similar in some respects to ‘coping-strategies’ found in children, chimpanzees and parrots. Our results indicate that strategies to cope with impulsivity seem to be consistent and present across animal taxa. PMID:28272409

The Results of a Simulator Study to Determine the Effects on Pilot Performance of Two Different Motion Cueing Algorithms and Various Delays, Compensated and Uncompensated

NASA Technical Reports Server (NTRS)

Guo, Li-Wen; Cardullo, Frank M.; Telban, Robert J.; Houck, Jacob A.; Kelly, Lon C.

2003-01-01

A study was conducted employing the Visual Motion Simulator (VMS) at the NASA Langley Research Center, Hampton, Virginia. This study compared two motion cueing algorithms, the NASA adaptive algorithm and a new optimal control based algorithm. Also, the study included the effects of transport delays and the compensation thereof. The delay compensation algorithm employed is one developed by Richard McFarland at NASA Ames Research Center. This paper reports on the analyses of the results of analyzing the experimental data collected from preliminary simulation tests. This series of tests was conducted to evaluate the protocols and the methodology of data analysis in preparation for more comprehensive tests which will be conducted during the spring of 2003. Therefore only three pilots were used. Nevertheless some useful results were obtained. The experimental conditions involved three maneuvers; a straight-in approach with a rotating wind vector, an offset approach with turbulence and gust, and a takeoff with and without an engine failure shortly after liftoff. For each of the maneuvers the two motion conditions were combined with four delay conditions (0, 50, 100 & 200ms), with and without compensation.

Choice between delayed food and immediate oxycodone in rats.

PubMed

Secci, Maria E; Factor, Julie A; Schindler, Charles W; Panlilio, Leigh V

2016-12-01

The choice to seek immediate drug effects instead of more meaningful but delayed rewards is a defining feature of addiction. To develop a rodent model of this behavior, we allowed rats to choose between immediate intravenous delivery of the prescription opioid oxycodone (50 μg/kg) and delayed delivery of palatable food pellets. Rats preferred food at delays up to 30 s, but they chose oxycodone and food equally at 60-s delay and preferred oxycodone over food at 120-s delay. Comparison of food-drug choice, food-only, and drug-only conditions indicated that food availability decreased drug intake, but drug availability increased food intake. In the food-only condition, food was effective as a reinforcer even when delayed by 120 s. Pre-session feeding with chow slowed acquisition of food and drug self-administration, but did not affect choice. To establish procedures for testing potential anti-addiction medications, noncontingent pre-treatment with oxycodone or naltrexone (analogous to substitution and antagonist therapies, respectively) were tested on a baseline in which oxycodone was preferred over delayed food. Naltrexone pre-treatment decreased drug intake and increased food intake. Oxycodone pre-treatment decreased drug intake, but also produced extended periods with no food or drug responding. These findings show that the contingencies that induce preference for drugs over more meaningful but less immediate rewards in humans can be modeled in rodents, and they suggest that the model could be useful for assessing the therapeutic potential of treatments and exploring the underlying behavioral and neural mechanisms involved in addiction.

Choice between delayed food and immediate oxycodone in rats

PubMed Central

Secci, Maria E.; Factor, Julie A.; Schindler, Charles W.; Panlilio, Leigh V.

2016-01-01

Rationale The choice to seek immediate drug effects instead of more meaningful but delayed rewards is a defining feature of addiction. Objectives To develop a rodent model of this behavior, we allowed rats to choose between immediate intravenous delivery of the prescription opioid oxycodone (50 μg/kg) and delayed delivery of palatable food pellets. Results Rats preferred food at delays up to 30 s, but they chose oxycodone and food equally at 60-s delay and preferred oxycodone over food at 120-s delay. Comparison of food-drug choice, food-only, and drug-only conditions indicated that food availability decreased drug intake, but drug availability increased food intake. In the food-only condition, food was effective as a reinforcer even when delayed by 120 s. Pre-session feeding with chow slowed acquisition of food and drug self-administration, but did not affect choice. To establish procedures for testing potential anti-addiction medications, noncontingent pretreatment with oxycodone or naltrexone (analogous to substitution and antagonist therapies, respectively) were tested on a baseline in which oxycodone was preferred over delayed food. Naltrexone pretreatment decreased drug intake and increased food intake. Oxycodone pretreatment decreased drug intake, but also produced extended periods with no food or drug responding. Conclusions These findings show that the contingencies that induce preference for drugs over more meaningful but less immediate rewards in humans can be modeled in rodents, and they suggest that the model could be useful for assessing the therapeutic potential of treatments and exploring the underlying behavioral and neural mechanisms involved in addiction. PMID:27678551

Exact synchronization bound for coupled time-delay systems.

PubMed

Senthilkumar, D V; Pesquera, Luis; Banerjee, Santo; Ortín, Silvia; Kurths, J

2013-04-01

We obtain an exact bound for synchronization in coupled time-delay systems using the generalized Halanay inequality for the general case of time-dependent delay, coupling, and coefficients. Furthermore, we show that the same analysis is applicable to both uni- and bidirectionally coupled time-delay systems with an appropriate evolution equation for their synchronization manifold, which can also be defined for different types of synchronization. The exact synchronization bound assures an exponential stabilization of the synchronization manifold which is crucial for applications. The analytical synchronization bound is independent of the nature of the modulation and can be applied to any time-delay system satisfying a Lipschitz condition. The analytical results are corroborated numerically using the Ikeda system.

Aging transition in systems of oscillators with global distributed-delay coupling.

PubMed

Rahman, B; Blyuss, K B; Kyrychko, Y N

2017-09-01

We consider a globally coupled network of active (oscillatory) and inactive (nonoscillatory) oscillators with distributed-delay coupling. Conditions for aging transition, associated with suppression of oscillations, are derived for uniform and gamma delay distributions in terms of coupling parameters and the proportion of inactive oscillators. The results suggest that for the uniform distribution increasing the width of distribution for the same mean delay allows aging transition to happen for a smaller coupling strength and a smaller proportion of inactive elements. For gamma distribution with sufficiently large mean time delay, it may be possible to achieve aging transition for an arbitrary proportion of inactive oscillators, as long as the coupling strength lies in a certain range.

Stochastic hybrid delay population dynamics: well-posed models and extinction.

PubMed

Yuan, Chenggui; Mao, Xuerong; Lygeros, John

2009-01-01

Nonlinear differential equations have been used for decades for studying fluctuations in the populations of species, interactions of species with the environment, and competition and symbiosis between species. Over the years, the original non-linear models have been embellished with delay terms, stochastic terms and more recently discrete dynamics. In this paper, we investigate stochastic hybrid delay population dynamics (SHDPD), a very general class of population dynamics that comprises all of these phenomena. For this class of systems, we provide sufficient conditions to ensure that SHDPD have global positive, ultimately bounded solutions, a minimum requirement for a realistic, well-posed model. We then study the question of extinction and establish conditions under which an ecosystem modelled by SHDPD is doomed.

Modeling Weather Impact on Ground Delay Programs

NASA Technical Reports Server (NTRS)

Wang, Yao; Kulkarni, Deepak

2011-01-01

Scheduled arriving aircraft demand may exceed airport arrival capacity when there is abnormal weather at an airport. In such situations, Federal Aviation Administration (FAA) institutes ground-delay programs (GDP) to delay flights before they depart from their originating airports. Efficient GDP planning depends on the accuracy of prediction of airport capacity and demand in the presence of uncertainties in weather forecast. This paper presents a study of the impact of dynamic airport surface weather on GDPs. Using the National Traffic Management Log, effect of weather conditions on the characteristics of GDP events at selected busy airports is investigated. Two machine learning methods are used to generate models that map the airport operational conditions and weather information to issued GDP parameters and results of validation tests are described.

Periodic and chaotic oscillations in a tumor and immune system interaction model with three delays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bi, Ping; Center for Partial Differential Equations, East China Normal University, 500 Dongchuan Rd., Shanghai 200241; Ruan, Shigui, E-mail: ruan@math.miami.edu

2014-06-15

In this paper, a tumor and immune system interaction model consisted of two differential equations with three time delays is considered in which the delays describe the proliferation of tumor cells, the process of effector cells growth stimulated by tumor cells, and the differentiation of immune effector cells, respectively. Conditions for the asymptotic stability of equilibria and existence of Hopf bifurcations are obtained by analyzing the roots of a second degree exponential polynomial characteristic equation with delay dependent coefficients. It is shown that the positive equilibrium is asymptotically stable if all three delays are less than their corresponding critical valuesmore » and Hopf bifurcations occur if any one of these delays passes through its critical value. Numerical simulations are carried out to illustrate the rich dynamical behavior of the model with different delay values including the existence of regular and irregular long periodic oscillations.« less

Estimation of time- and state-dependent delays and other parameters in functional differential equations

NASA Technical Reports Server (NTRS)

Murphy, K. A.

1988-01-01

A parameter estimation algorithm is developed which can be used to estimate unknown time- or state-dependent delays and other parameters (e.g., initial condition) appearing within a nonlinear nonautonomous functional differential equation. The original infinite dimensional differential equation is approximated using linear splines, which are allowed to move with the variable delay. The variable delays are approximated using linear splines as well. The approximation scheme produces a system of ordinary differential equations with nice computational properties. The unknown parameters are estimated within the approximating systems by minimizing a least-squares fit-to-data criterion. Convergence theorems are proved for time-dependent delays and state-dependent delays within two classes, which say essentially that fitting the data by using approximations will, in the limit, provide a fit to the data using the original system. Numerical test examples are presented which illustrate the method for all types of delay.

Understanding the delayed-keyword effect on metacomprehension accuracy.

PubMed

Thiede, Keith W; Dunlosky, John; Griffin, Thomas D; Wiley, Jennifer

2005-11-01

The typical finding from research on metacomprehension is that accuracy is quite low. However, recent studies have shown robust accuracy improvements when judgments follow certain generation tasks (summarizing or keyword listing) but only when these tasks are performed at a delay rather than immediately after reading (K. W. Thiede & M. C. M. Anderson, 2003; K. W. Thiede, M. C. M. Anderson, & D. Therriault, 2003). The delayed and immediate conditions in these studies confounded the delay between reading and generation tasks with other task lags, including the lag between multiple generation tasks and the lag between generation tasks and judgments. The first 2 experiments disentangle these confounded manipulations and provide clear evidence that the delay between reading and keyword generation is the only lag critical to improving metacomprehension accuracy. The 3rd and 4th experiments show that not all delayed tasks produce improvements and suggest that delayed generative tasks provide necessary diagnostic cues about comprehension for improving metacomprehension accuracy.

Estimation of time- and state-dependent delays and other parameters in functional differential equations

NASA Technical Reports Server (NTRS)

Murphy, K. A.

1990-01-01

A parameter estimation algorithm is developed which can be used to estimate unknown time- or state-dependent delays and other parameters (e.g., initial condition) appearing within a nonlinear nonautonomous functional differential equation. The original infinite dimensional differential equation is approximated using linear splines, which are allowed to move with the variable delay. The variable delays are approximated using linear splines as well. The approximation scheme produces a system of ordinary differential equations with nice computational properties. The unknown parameters are estimated within the approximating systems by minimizing a least-squares fit-to-data criterion. Convergence theorems are proved for time-dependent delays and state-dependent delays within two classes, which say essentially that fitting the data by using approximations will, in the limit, provide a fit to the data using the original system. Numerical test examples are presented which illustrate the method for all types of delay.

77 FR 41110 - Exemptive Order Regarding Compliance With Certain Swap Regulations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-12

... delay compliance with certain entity-level requirements of the CEA (and Commission regulations promulgated thereunder), subject to specified conditions. Additionally, with respect to transaction-level.... major swap participants may delay compliance with certain entity-level requirements of the CEA (and...

Developing and validating trace fear conditioning protocols in C57BL/6 mice.

PubMed

Burman, Michael A; Simmons, Cassandra A; Hughes, Miles; Lei, Lei

2014-01-30

Classical fear conditioning is commonly used to study the biology of fear, anxiety and memory. Previous research demonstrated that delay conditioning requires a neural circuit involving the amygdala, but not usually the hippocampus. Trace and contextual fear conditioning require the amygdala and hippocampus. While these paradigms were developed primarily using rat models, they are increasingly being used in mice. The current studies develop trace fear conditioning and control paradigms to allow for the assessment of trace and delay fear conditioning in C57BL/6N mice. Our initial protocol yielded clear delay and contextual conditioning. However, trace conditioning failed to differentiate from an unpaired group and was not hippocampus-dependent. These results suggested that the protocol needed to be modified to specifically accommodate trace conditioning the mice. In order to reduce unconditioned freezing and increase learning, the final protocol was developed by decreasing the intensity of the tone and by increasing the inter-trial interval. Our final protocol produced trace conditioned freezing that was significantly greater than that followed unpaired stimulus exposure and was disrupted by hippocampus lesions. A review of the literature produced 90 articles using trace conditioning in mice. Few of those articles used any kind of behavioral control group, which is required to rule out non-associative factors causing fearful behavior. Fewer used unpaired groups involving tones and shocks within a session, which is the optimal control group. Our final trace conditioning protocol can be used in future studies examining genetically modified C57BL/6N mice. Copyright © 2013 Elsevier B.V. All rights reserved.

Developing and Validating Trace Fear Conditioning Protocols in C57BL/6 Mice

PubMed Central

Burman, Michael A; Simmons, Cassandra A; Hughes, Miles; Lei, Lei

2013-01-01

Background Classical fear conditioning is commonly used to study the biology of fear, anxiety and memory. Previous research demonstrated that delay conditioning requires a neural circuit involving the amygdala, but not usually the hippocampus. Trace and contextual fear conditioning require the amygdala and hippocampus. While these paradigms were developed primarily using rat models, they are increasingly being used in mice. New Method The current studies develop trace fear conditioning and control paradigms to allow for the assessment of trace and delay fear conditioning in C57BL/6N mice. Our initial protocol yielded clear delay and contextual conditioning. However, trace conditioning failed to differentiate from an unpaired group and was not hippocampus-dependent. These results suggested that the protocol needed to be modified to specifically accommodate trace conditioning the mice. In order to reduce unconditioned freezing and increase learning, the final protocol was developed by decreasing the intensity of the tone and by increasing the inter-trial interval. Results Our final protocol produced trace conditioned freezing that was significantly greater than that followed unpaired stimulus exposure and was disrupted by hippocampus lesions. Comparison with Existing Methods A review of the literature produced 90 articles using trace conditioning in mice. Few of those articles used any kind of behavioral control group, which is required to rule out non-associative factors causing fearful behavior. Fewer used unpaired groups involving tones and shocks within a session, which is the optimal control group. Conclusions Our final trace conditioning protocol can be used in future studies examining genetically modified C57BL/6N mice. PMID:24269252

Taste-dependent sociophobia: when food and company do not mix.

PubMed

Guitton, Matthieu J; Klin, Yael; Dudai, Yadin

2008-08-22

Using a combination of the paradigm of conditioned taste aversion (CTA) and of the paradigm of social interactions, we report here that in the rat, eating while anxious may result in long-term alterations in social behavior. In the conventional CTA, the subject learns to associate a tastant (the conditioned stimulus, CS) with delayed toxicosis (an unconditioned stimulus, UCS) to yield taste aversion (the conditioned response, CR). However, the association of taste with delayed negative internal states that could generate CRs that are different from taste aversion should not be neglected. Such associations may contribute to the ontogenesis, reinforcement and symptoms of some types of taste- and food-related disorders. We have recently reported that a delayed anxiety-like state, induced by the anxiogenic drug meta-chlorophenylpiperazine (mCPP), can specifically associate with taste to produce CTA. We now show that a similar protocol results in a marked lingering impairment in social interactions in response to the conditioned taste. This is hence a learned situation in which food and company do not mix well.

Choice and conditioned reinforcement.

PubMed Central

Fantino, E; Freed, D; Preston, R A; Williams, W A

1991-01-01

A potential weakness of one formulation of delay-reduction theory is its failure to include a term for rate of conditioned reinforcement, that is, the rate at which the terminal-link stimuli occur in concurrent-chains schedules. The present studies assessed whether or not rate of conditioned reinforcement has an independent effect upon choice. Pigeons responded on either modified concurrent-chains schedules or on comparable concurrent-tandem schedules. The initial link was shortened on only one of two concurrent-chains schedules and on only one of two corresponding concurrent-tandem schedules. This manipulation increased rate of conditioned reinforcement sharply in the chain but not in the tandem schedule. According to a formulation of delay-reduction theory, when the outcomes chosen (the terminal links) are equal, as in Experiment 1, choice should depend only on rate of primary reinforcement; thus, choice should be equivalent for the tandem and chain schedules despite a large difference in rate of conditioned reinforcement. When the outcomes chosen are unequal, however, as in Experiment 2, choice should depend upon both rate of primary reinforcement and relative signaled delay reduction; thus, larger preferences should occur in the chain than in the tandem schedules. These predictions were confirmed, suggesting that increasing the rate of conditioned reinforcement on concurrent-chains schedules may have no independent effect on choice. PMID:2037826

Determinants of relative skeletal maturity in South African children.

PubMed

Hawley, Nicola L; Rousham, Emily K; Johnson, William; Norris, Shane A; Pettifor, John M; Cameron, Noël

2012-01-01

The variation of skeletal maturity about chronological age is a sensitive indicator of population health. Age appropriate or advanced skeletal maturity is a reflection of adequate environmental and social conditions, whereas delayed maturation suggests inadequate conditions for optimal development. There remains a paucity of data, however, to indicate which specific biological and environmental factors are associated with advancement or delay in skeletal maturity. The present study utilises longitudinal data from the South African Birth to Twenty (Bt20) study to indentify predictors of relative skeletal maturity (RSM) in early adolescence. A total of 244 black South African children (n=131 male) were included in this analysis. Skeletal maturity at age 9/10 years was assessed using the Tanner and Whitehouse III RUS technique. Longitudinal data on growth, socio-economic position and pubertal development were entered into sex-specific multivariable general linear regression models with relative skeletal maturity (skeletal age-chronological age) as the outcome. At 9/10 years of age males showed an average of 0.66 years delay in skeletal maturation relative to chronological age. Females showed an average of 1.00 year delay relative to chronological age. In males, being taller at 2 years (p<0.01) and heavier at 2 years (p<0.01) predicted less delay in RSM at age 9/10 years, independent of current size and body composition. In females, both height at 2 years and conditional weight at 2 years predicted less delay in RSM at 9/10 years (p<0.05) but this effect was mediated by current body composition. Having greater lean mass at 9/10 years was associated with less delayed RSM in females (p<0.01) as was pubertal status at the time of skeletal maturity assessment (p<0.01). This study identifies several predictors of skeletal maturation at 9/10 years, indicating a role for early life exposures in determining the rate of skeletal maturation during childhood independently of current stature. Copyright © 2011 Elsevier Inc. All rights reserved.

Convergence behavior of delayed discrete cellular neural network without periodic coefficients.

PubMed

Wang, Jinling; Jiang, Haijun; Hu, Cheng; Ma, Tianlong

2014-05-01

In this paper, we study convergence behaviors of delayed discrete cellular neural networks without periodic coefficients. Some sufficient conditions are derived to ensure all solutions of delayed discrete cellular neural network without periodic coefficients converge to a periodic function, by applying mathematical analysis techniques and the properties of inequalities. Finally, some examples showing the effectiveness of the provided criterion are given. Copyright © 2014 Elsevier Ltd. All rights reserved.

Improved result on stability analysis of discrete stochastic neural networks with time delay

NASA Astrophysics Data System (ADS)

Wu, Zhengguang; Su, Hongye; Chu, Jian; Zhou, Wuneng

2009-04-01

This Letter investigates the problem of exponential stability for discrete stochastic time-delay neural networks. By defining a novel Lyapunov functional, an improved delay-dependent exponential stability criterion is established in terms of linear matrix inequality (LMI) approach. Meanwhile, the computational complexity of the newly established stability condition is reduced because less variables are involved. Numerical example is given to illustrate the effectiveness and the benefits of the proposed method.

Behavioral effects of delayed timeouts from reinforcement.

PubMed

Byrne, Tom; Poling, Alan

2017-03-01

Timeouts are sometimes used in applied settings to reduce target responses, and in some circumstances delays are unavoidably imposed between the onset of a timeout and the offset of the response that produces it. The present study examined the effects of signaled and unsignaled timeouts in rats exposed to concurrent fixed-ratio 1 fixed-ratio 1 schedules of food delivery, where each response on one lever, the location of which changed across conditions, produced both food and a delayed 10-s timeout. Delays of 0 to 38 s were examined. Delayed timeouts often, but not always, substantially reduced the number of responses emitted on the lever that produced timeouts relative to the number emitted on the lever that did not produce timeouts. In general, greater sensitivity was observed to delayed timeouts when they were signaled. These results demonstrate that delayed timeouts, like other delayed consequences, can affect behavior, albeit less strongly than immediate consequences. © 2017 Society for the Experimental Analysis of Behavior.

Delayed Post-ischemic Conditioning Significantly Improves the Outcome after Retinal Ischemia

PubMed Central

Dreixler, John C.; Poston, Jacqueline N.; Shaikh, Afzhal R.; Alexander, Michael; Tupper, Kelsey Y.; Marcet, Marcus M.; Bernaudin, Myriam; Roth, Steven

2011-01-01

In previous studies, it was shown that post-conditioning, a transient period of brief ischemia following prolonged severe ischemia in the retina, could provide significant improvement in post-ischemic recovery, attenuation of cell loss, and decreased apoptosis. These studies showed that post-conditioning effectively prevented damage after retinal ischemia when it was instituted early (within one hour) in the post-ischemic period. While post-ischemic conditioning holds high promise of clinical translation, patients often present late after the onset of retinal ischemia and therefore immediate application of this anti-ischemic maneuver is generally not feasible. In this study, we examined the hypothesis that application of a post-conditioning stimulus at 24 h or greater following the end of prolonged ischemia would decrease the extent of ischemic injury. Ischemia was induced in rat retina in vivo. Recovery after ischemia followed by 5 minutes of post-conditioning brief ischemia 24 or 48 h after prolonged ischemia was assessed functionally (electroretinography) and histologically at 7 days after ischemia and post-conditioning or sham post-conditioning. We found that the brief ischemic stimulus applied 24, but not 48 h after prolonged ischemia significantly improved functional recovery and decreased histological damage induced by prolonged ischemia. We conclude that within a defined time window, delayed post-ischemic conditioning ameliorated post-ischemic injury in rats. Compared to earlier studies, the present work demonstrates for the first time the novel ability of a significantly delayed ischemic stimulus to provide robust neuroprotection in the retina following ischemia. PMID:21501608

Interactions between prefrontal cortex and cerebellum revealed by trace eyelid conditioning.

PubMed

Kalmbach, Brian E; Ohyama, Tatsuya; Kreider, Joy C; Riusech, Frank; Mauk, Michael D

2009-01-01

Eyelid conditioning has proven useful for analysis of learning and computation in the cerebellum. Two variants, delay and trace conditioning, differ only by the relative timing of the training stimuli. Despite the subtlety of this difference, trace eyelid conditioning is prevented by lesions of the cerebellum, hippocampus, or medial prefrontal cortex (mPFC), whereas delay eyelid conditioning is prevented by cerebellar lesions and is largely unaffected by forebrain lesions. Here we test whether these lesion results can be explained by two assertions: (1) Cerebellar learning requires temporal overlap between the mossy fiber inputs activated by the tone conditioned stimulus (CS) and the climbing fiber inputs activated by the reinforcing unconditioned stimulus (US), and therefore (2) trace conditioning requires activity that outlasts the presentation of the CS in a subset of mossy fibers separate from those activated directly by the CS. By use of electrical stimulation of mossy fibers as a CS, we show that cerebellar learning during trace eyelid conditioning requires an input that persists during the stimulus-free trace interval. By use of reversible inactivation experiments, we provide evidence that this input arises from the mPFC and arrives at the cerebellum via a previously unidentified site in the pontine nuclei. In light of previous PFC recordings in various species, we suggest that trace eyelid conditioning involves an interaction between the persistent activity of delay cells in mPFC-a putative mechanism of working memory-and motor learning in the cerebellum.

A hypothetical universal model of cerebellar function: reconsideration of the current dogma.

PubMed

Magal, Ari

2013-10-01

The cerebellum is commonly studied in the context of the classical eyeblink conditioning model, which attributes an adaptive motor function to cerebellar learning processes. This model of cerebellar function has quite a few shortcomings and may in fact be somewhat deficient in explaining the myriad functions attributed to the cerebellum, functions ranging from motor sequencing to emotion and cognition. The involvement of the cerebellum in these motor and non-motor functions has been demonstrated in both animals and humans in electrophysiological, behavioral, tracing, functional neuroimaging, and PET studies, as well as in clinical human case studies. A closer look at the cerebellum's evolutionary origin provides a clue to its underlying purpose as a tool which evolved to aid predation rather than as a tool for protection. Based upon this evidence, an alternative model of cerebellar function is proposed, one which might more comprehensively account both for the cerebellum's involvement in a myriad of motor, affective, and cognitive functions and for the relative simplicity and ubiquitous repetitiveness of its circuitry. This alternative model suggests that the cerebellum has the ability to detect coincidences of events, be they sensory, motor, affective, or cognitive in nature, and, after having learned to associate these, it can then trigger (or "mirror") these events after having temporally adjusted their onset based on positive/negative reinforcement. The model also provides for the cerebellum's direction of the proper and uninterrupted sequence of events resulting from this learning through the inhibition of efferent structures (as demonstrated in our lab).

The cerebellum: a new key structure in the navigation system

PubMed Central

Rochefort, Christelle; Lefort, Julie M.; Rondi-Reig, Laure

2013-01-01

Early investigations of cerebellar function focused on motor learning, in particular on eyeblink conditioning and adaptation of the vestibulo-ocular reflex, and led to the general view that cerebellar long-term depression (LTD) at parallel fiber (PF)–Purkinje cell (PC) synapses is the neural correlate of cerebellar motor learning. Thereafter, while the full complexity of cerebellar plasticities was being unraveled, cerebellar involvement in more cognitive tasks—including spatial navigation—was further investigated. However, cerebellar implication in spatial navigation remains a matter of debate because motor deficits frequently associated with cerebellar damage often prevent the dissociation between its role in spatial cognition from its implication in motor function. Here, we review recent findings from behavioral and electrophysiological analyses of cerebellar mutant mouse models, which show that the cerebellum might participate in the construction of hippocampal spatial representation map (i.e., place cells) and thereby in goal-directed navigation. These recent advances in cerebellar research point toward a model in which computation from the cerebellum could be required for spatial representation and would involve the integration of multi-source self-motion information to: (1) transform the reference frame of vestibular signals and (2) distinguish between self- and externally-generated vestibular signals. We eventually present herein anatomical and functional connectivity data supporting a cerebello-hippocampal interaction. Whilst a direct cerebello-hippocampal projection has been suggested, recent investigations rather favor a multi-synaptic pathway involving posterior parietal and retrosplenial cortices, two regions critically involved in spatial navigation. PMID:23493515

Enhanced startle responsivity 24 hours after acute stress exposure.

PubMed

Herten, Nadja; Otto, Tobias; Adolph, Dirk; Pause, Bettina M; Kumsta, Robert; Wolf, Oliver T

2016-10-01

Cortisol release in a stressful situation can be beneficial for memory encoding and memory consolidation. Stimuli, such as odors, related to the stressful episode may successfully cue memory contents of the stress experience. The current investigation aimed at testing the potency of stress to influence startle responsivity 24 hr later and to implicitly reactivate emotional memory traces triggered by an odor involved. Participants were assigned to either a stress (Trier Social Stress Test [TSST]) or control (friendly TSST [f-TSST]) condition featuring an ambient odor. On the next day, participants underwent an auditory startle paradigm while their eyeblink reflex was recorded by an electrooculogram. Three different olfactory stimuli were delivered, one being the target odor presented the day before. Additionally, negative, positive, and pictures of the committee members were included for comparing general startle responsivity and fear-potentiated startle. Participants of the stress group demonstrated an enhanced startle response across all stimuli compared to participants of the control group. There were no specific effects with regard to the target odor. The typical fear-potentiated startle response occurred. Stressed participants tended to rate the target odor more aversive than control participants. Odor recognition memory did not differ between the groups, suggesting an implicit effect on odor valence. Our results show that acute stress exposure enhances startle responsivity 24 hr later. This effect might be caused by a shift of amygdala function causing heightened sensitivity, but lower levels of specificity. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Regret Expression and Social Learning Increases Delay to Sexual Gratification.

PubMed

Quisenberry, Amanda J; Eddy, Celia R; Patterson, David L; Franck, Christopher T; Bickel, Warren K

2015-01-01

Modification and prevention of risky sexual behavior is important to individuals' health and public health policy. This study employed a novel sexual discounting task to elucidate the effects of social learning and regret expression on delay to sexual gratification in a behavioral task. Amazon Mechanical Turk Workers were assigned to hear one of three scenarios about a friend who engages in similar sexual behavior. The scenarios included a positive health consequence, a negative health consequence or a negative health consequence with the expression of regret. After reading one scenario, participants were asked to select from 60 images, those with whom they would have casual sex. Of the selected images, participants chose one image each for the person they most and least want to have sex with and person most and least likely to have a sexually transmitted infection. They then answered questions about engaging in unprotected sex now or waiting some delay for condom-protected sex in each partner condition. Results indicate that the negative health outcome scenario with regret expression resulted in delayed sexual gratification in the most attractive and least STI partner conditions, whereas in the least attractive and most STI partner conditions the negative health outcome with and without regret resulted in delayed sexual gratification. Results suggest that the sexual discounting task is a relevant laboratory measure and the framing of information to include regret expression may be relevant for prevention of risky sexual behavior.

Regret Expression and Social Learning Increases Delay to Sexual Gratification

PubMed Central

Quisenberry, Amanda J.; Eddy, Celia R.; Patterson, David L.; Franck, Christopher T.; Bickel, Warren K.

2015-01-01

Objective Modification and prevention of risky sexual behavior is important to individuals’ health and public health policy. This study employed a novel sexual discounting task to elucidate the effects of social learning and regret expression on delay to sexual gratification in a behavioral task. Methods Amazon Mechanical Turk Workers were assigned to hear one of three scenarios about a friend who engages in similar sexual behavior. The scenarios included a positive health consequence, a negative health consequence or a negative health consequence with the expression of regret. After reading one scenario, participants were asked to select from 60 images, those with whom they would have casual sex. Of the selected images, participants chose one image each for the person they most and least want to have sex with and person most and least likely to have a sexually transmitted infection. They then answered questions about engaging in unprotected sex now or waiting some delay for condom-protected sex in each partner condition. Results Results indicate that the negative health outcome scenario with regret expression resulted in delayed sexual gratification in the most attractive and least STI partner conditions, whereas in the least attractive and most STI partner conditions the negative health outcome with and without regret resulted in delayed sexual gratification. Conclusions Results suggest that the sexual discounting task is a relevant laboratory measure and the framing of information to include regret expression may be relevant for prevention of risky sexual behavior. PMID:26280349

Stability and Hopf bifurcation of a delayed ratio-dependent predator-prey system

NASA Astrophysics Data System (ADS)

Wang, Wan-Yong; Pei, Li-Jun

2011-04-01

Since the ratio-dependent theory reflects the fact that predators must share and compete for food, it is suitable for describing the relationship between predators and their preys and has recently become a very important theory put forward by biologists. In order to investigate the dynamical relationship between predators and their preys, a so-called Michaelis-Menten ratio-dependent predator-prey model is studied in this paper with gestation time delays of predators and preys taken into consideration. The stability of the positive equilibrium is investigated by the Nyquist criteria, and the existence of the local Hopf bifurcation is analyzed by employing the theory of Hopf bifurcation. By means of the center manifold and the normal form theories, explicit formulae are derived to determine the stability, direction and other properties of bifurcating periodic solutions. The above theoretical results are validated by numerical simulations with the help of dynamical software WinPP. The results show that if both the gestation delays are small enough, their sizes will keep stable in the long run, but if the gestation delays of predators are big enough, their sizes will periodically fluctuate in the long term. In order to reveal the effects of time delays on the ratio-dependent predator-prey model, a ratio-dependent predator-prey model without time delays is considered. By Hurwitz criteria, the local stability of positive equilibrium of this model is investigated. The conditions under which the positive equilibrium is locally asymptotically stable are obtained. By comparing the results with those of the model with time delays, it shows that the dynamical behaviors of ratio-dependent predator-prey model with time delays are more complicated. Under the same conditions, namely, with the same parameters, the stability of positive equilibrium of ratio-dependent predator-prey model would change due to the introduction of gestation time delays for predators and preys. Moreover, with the variation of time delays, the positive equilibrium of the ratio-dependent predator-prey model subjects to Hopf bifurcation.

Relating the 2010 signalized intersection methodology to alternate approaches in the context of NYC conditions.

DOT National Transportation Integrated Search

2013-11-01

The Highway Capacity Manual (HCM) has had a delay-based level of service methodology for signalized intersections since 1985. : The 2010 HCM has revised the method for calculating delay. This happened concurrent with such jurisdictions as NYC reviewi...

Periodicity and global exponential stability of generalized Cohen-Grossberg neural networks with discontinuous activations and mixed delays.

PubMed

Wang, Dongshu; Huang, Lihong

2014-03-01

In this paper, we investigate the periodic dynamical behaviors for a class of general Cohen-Grossberg neural networks with discontinuous right-hand sides, time-varying and distributed delays. By means of retarded differential inclusions theory and the fixed point theorem of multi-valued maps, the existence of periodic solutions for the neural networks is obtained. After that, we derive some sufficient conditions for the global exponential stability and convergence of the neural networks, in terms of nonsmooth analysis theory with generalized Lyapunov approach. Without assuming the boundedness (or the growth condition) and monotonicity of the discontinuous neuron activation functions, our results will also be valid. Moreover, our results extend previous works not only on discrete time-varying and distributed delayed neural networks with continuous or even Lipschitz continuous activations, but also on discrete time-varying and distributed delayed neural networks with discontinuous activations. We give some numerical examples to show the applicability and effectiveness of our main results. Copyright © 2013 Elsevier Ltd. All rights reserved.

Auroral Substorms during Prolonged Northward IMF

NASA Astrophysics Data System (ADS)

Du, Aimin

Multiple observations by satellites and ground-based magnetometers identify the occurrence of substorm events during prolonged northward interplanetary magnetic field (IMF). The func-tion, as an expression of the solar wind energy flow, and the energy dissipation in the ionosphere (UI) are calculated during substorm periods. The delay time of the UI to the function and UI for seven substorm events with AL values of -231 -1500 nT under northward IMF condition are 45 95 min with a mean value of 70.86 min. For comparison, 23 substorm events with the AL index of -316 -1685 nT under southward IMF condition are detected to have the delay time of 21 66 min with a mean value of 42.04 min. The longer delay time for substorms during northward IMF can be presumably attributed to the contribution of IMF By component to merging between IMF and the Earth's magnetic field. A tendency of the decrease of the delay time with increasing absolute values of IMF By is noted. Acknowledgement: This work is supported by NSFC(40774086).

Periodic bidirectional associative memory neural networks with distributed delays

NASA Astrophysics Data System (ADS)

Chen, Anping; Huang, Lihong; Liu, Zhigang; Cao, Jinde

2006-05-01

Some sufficient conditions are obtained for the existence and global exponential stability of a periodic solution to the general bidirectional associative memory (BAM) neural networks with distributed delays by using the continuation theorem of Mawhin's coincidence degree theory and the Lyapunov functional method and the Young's inequality technique. These results are helpful for designing a globally exponentially stable and periodic oscillatory BAM neural network, and the conditions can be easily verified and be applied in practice. An example is also given to illustrate our results.

Passivity analysis for uncertain BAM neural networks with time delays and reaction-diffusions

NASA Astrophysics Data System (ADS)

Zhou, Jianping; Xu, Shengyuan; Shen, Hao; Zhang, Baoyong

2013-08-01

This article deals with the problem of passivity analysis for delayed reaction-diffusion bidirectional associative memory (BAM) neural networks with weight uncertainties. By using a new integral inequality, we first present a passivity condition for the nominal networks, and then extend the result to the case with linear fractional weight uncertainties. The proposed conditions are expressed in terms of linear matrix inequalities, and thus can be checked easily. Examples are provided to demonstrate the effectiveness of the proposed results.

The Effect of Nb Micro-alloying on the Bainitic Phase Transformation Under Strip Casting Conditions

NASA Astrophysics Data System (ADS)

Stanford, N.; Dorin, T.; Hodgson, P. D.

2018-04-01

The effect of Nb concentration on the transformation from austenite to bainitic ferrite has been examined under simulated strip casting conditions. Nb concentration was found to delay the nucleation of bainite, but accelerated its growth. It is suggested that the delay in nucleation increases the driving force for transformation, which results in an increase in the growth rate of the bainite. The bainite/austenite interfaces are proposed to move too quickly to suffer appreciable solute drag.

Changing delay discounting in the light of the competing neurobehavioral decision systems theory: a review.

PubMed

Koffarnus, Mikhail N; Jarmolowicz, David P; Mueller, E Terry; Bickel, Warren K

2013-01-01

Excessively devaluing delayed reinforcers co-occurs with a wide variety of clinical conditions such as drug dependence, obesity, and excessive gambling. If excessive delay discounting is a trans-disease process that underlies the choice behavior leading to these and other negative health conditions, efforts to change an individual's discount rate are arguably important. Although discount rate is often regarded as a relatively stable trait, descriptions of interventions and environmental manipulations that successfully alter discount rate have begun to appear in the literature. In this review, we compare published examples of procedures that change discount rate and classify them into categories of procedures, including therapeutic interventions, direct manipulation of the executive decision-making system, framing effects, physiological state effects, and acute drug effects. These changes in discount rate are interpreted from the perspective of the competing neurobehavioral decision systems theory, which describes a combination of neurological and behavioral processes that account for delay discounting. We also suggest future directions that researchers could take to identify the mechanistic processes that allow for changes in discount rate and to test whether the competing neurobehavioral decision systems view of delay discounting is correct. © Society for the Experimental Analysis of Behavior.

Hierarchical Type Stability Criteria for Delayed Neural Networks via Canonical Bessel-Legendre Inequalities.

PubMed

Zhang, Xian-Ming; Han, Qing-Long; Zeng, Zhigang

2018-05-01

This paper is concerned with global asymptotic stability of delayed neural networks. Notice that a Bessel-Legendre inequality plays a key role in deriving less conservative stability criteria for delayed neural networks. However, this inequality is in the form of Legendre polynomials and the integral interval is fixed on . As a result, the application scope of the Bessel-Legendre inequality is limited. This paper aims to develop the Bessel-Legendre inequality method so that less conservative stability criteria are expected. First, by introducing a canonical orthogonal polynomial sequel, a canonical Bessel-Legendre inequality and its affine version are established, which are not explicitly in the form of Legendre polynomials. Moreover, the integral interval is shifted to a general one . Second, by introducing a proper augmented Lyapunov-Krasovskii functional, which is tailored for the canonical Bessel-Legendre inequality, some sufficient conditions on global asymptotic stability are formulated for neural networks with constant delays and neural networks with time-varying delays, respectively. These conditions are proven to have a hierarchical feature: the higher level of hierarchy, the less conservatism of the stability criterion. Finally, three numerical examples are given to illustrate the efficiency of the proposed stability criteria.

Changing Delay Discounting in the Light of the Competing Neurobehavioral Decision Systems Theory: a Review

PubMed Central

Koffarnus, Mikhail N.; Jarmolowicz, David P.; Mueller, E. Terry; Bickel, Warren K.

2014-01-01

Excessively devaluing delayed reinforcers co-occurs with a wide variety of clinical conditions such as drug dependence, obesity, and excessive gambling. If excessive delay discounting is a trans-disease process that underlies the choice behavior leading to these and other negative health conditions, efforts to change an individual’s discount rate are arguably important. Although discount rate is often regarded as a relatively stable trait, descriptions of interventions and environmental manipulations that successfully alter discount rate have begun to appear in the literature. In this review, we compare published examples of procedures that change discount rate and classify them into categories of procedures, including therapeutic interventions, direct manipulation of the executive decision-making system, framing effects, physiological state effects, and acute drug effects. These changes in discount rate are interpreted from the perspective of the competing neurobehavioral decision systems theory, which describes a combination of neurological and behavioral processes that account for delay discounting. We also suggest future directions that researchers could take to identify the mechanistic processes that allow for changes in discount rate and to test whether the competing neurobehavioral decision systems view of delay discounting is correct. PMID:23344987

Too proud to regulate: The differential effect of pride versus joy on children's ability to delay gratification.

PubMed

Shimoni, Einav; Asbe, Marwa; Eyal, Tal; Berger, Andrea

2016-01-01

We examined the effect of the distinct positive emotions pride and joy on children's self-regulation, focusing on their ability to delay gratification (i.e., resist a temptation in favor of a long-term goal). We hypothesized that because pride corresponds to the attainment of long-term goals and joy corresponds to the attainment of immediate desires, the experience of pride may signal sufficient progress toward a long-term goal, resulting in less delay of gratification than the experience of joy. To test this hypothesis, we induced an experience of pride or joy in 8-year-old children. At this age, the ability to self-regulate--and to experience pride and joy distinctively--is relatively mature. We then measured performance in a delay discounting task. We found that, compared with the joy condition and a control condition, children who experienced pride performed worse on the delay discounting task (p=.045), indicating poorer self-regulation. This result suggests that emotions may function as cues for sufficient goal pursuit, thereby influencing self-regulation from a very young age. Copyright © 2015 Elsevier Inc. All rights reserved.

Impact of leakage delay on bifurcation in high-order fractional BAM neural networks.

PubMed

Huang, Chengdai; Cao, Jinde

2018-02-01

The effects of leakage delay on the dynamics of neural networks with integer-order have lately been received considerable attention. It has been confirmed that fractional neural networks more appropriately uncover the dynamical properties of neural networks, but the results of fractional neural networks with leakage delay are relatively few. This paper primarily concentrates on the issue of bifurcation for high-order fractional bidirectional associative memory(BAM) neural networks involving leakage delay. The first attempt is made to tackle the stability and bifurcation of high-order fractional BAM neural networks with time delay in leakage terms in this paper. The conditions for the appearance of bifurcation for the proposed systems with leakage delay are firstly established by adopting time delay as a bifurcation parameter. Then, the bifurcation criteria of such system without leakage delay are successfully acquired. Comparative analysis wondrously detects that the stability performance of the proposed high-order fractional neural networks is critically weakened by leakage delay, they cannot be overlooked. Numerical examples are ultimately exhibited to attest the efficiency of the theoretical results. Copyright © 2017 Elsevier Ltd. All rights reserved.

Discounting of money and sex: effects of commodity and temporal position in stimulant-dependent men and women.

PubMed

Jarmolowicz, David P; Landes, Reid D; Christensen, Darren R; Jones, Bryan A; Jackson, Lisa; Yi, Richard; Bickel, Warren K

2014-11-01

Research on delay discounting has contributed to the understanding of numerous addiction-related phenomena. For example, studies have shown that substance dependent individuals discount their addictive substances (e.g., cocaine) more rapidly than they do other commodities (e.g., money). Recent research has shown that substance dependent individuals discount delayed sex more rapidly than delayed money, and their discounting rates for delayed sex were higher than those of non-addicted individuals. The particular reason that delay discounting rates for sex are higher than those for money, however, are unclear. Do individuals discount delayed sex rapidly because immediate sex is particularly appealing or because delayed sex does not retain its value? Moreover, do the same factors influence men and women's choices? The current study examined delay discounting in four conditions (money now versus money later; sex now versus sex later; money now, versus sex later; sex now versus money later) in cocaine dependent men and women. The procedures used isolated the role of the immediate versus delayed commodity. For men, the higher rates of delay discounting for sex were because delayed sex did not retain its value, whereas both the immediate and delayed commodity influenced the female participants' decisions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of blood glucose on delay discounting, food intake and counterregulation in lean and obese men.

PubMed

Klement, Johanna; Kubera, Britta; Eggeling, Jonas; Rädel, Christin; Wagner, Christin; Park, Soyoung Q; Peters, Achim

2018-03-01

Delay discounting as a measure of impulsivity has been shown to be higher in obesity with an association of increased food intake. Moreover, obese humans showed a higher wanting for high-calorie food than lean men when blood glucose concentrations were low. First studies linking blood glucose levels to delay discounting yielded mixed results. We hypothesized that obese people - in comparison to lean men - have a relative lack of energy, especially when blood glucose levels are low, that results in higher levels of delay discounting, food intake and hormonal counterregulation. We investigated 20 lean and 20 obese healthy young men in a single-blind balanced cross-over design. With a standardized glucose clamp technique, subjects underwent a hypoglycemic state in one condition and a euglycemic state in the control condition. Regularly, blood was sampled for assessment of hormonal status, and questionnaires were filled out to assess delay discounting and symptom awareness. After normalizing blood glucose concentrations, subjects were free to eat from a standardized test buffet, followed by a snack test. Delay discounting was higher in obese than in lean men throughout experiments (p < 0.03). However, we did not observe significant discounting differences between glucose conditions (p > 0.1). Furthermore, the discounting performance did not correlate with food intake from the test buffet or snack test (p > 0.3). As a response to hypoglycemia, hormonal counterregulation was pronounced in both weight groups (p < 0.03), but responses of ACTH, norepinephrine and glucagon were stronger in obese compared to lean men (p < 0.03). Also, intake from the high-calorie buffet after hypoglycemia compared to euglycemia was higher in obese subjects (p < 0.02) but comparable in lean men (p > 0.5). Our data suggest that augmented delay discounting is a robust feature in obesity that is not linked to glucose levels or actual food intake. With our systematically controlled approach, combining performance in delay discounting with regard to distinct blood glucose levels, different weight groups, counterregulatory behavior and food intake, our results imply that delay discounting is not susceptible to fluctuations of blood glucose and do not support the assumption that a low body's energy content leads to increased impulsivity. Further replications including women and larger sample sizes are needed to corroborate our data. Copyright © 2018 Elsevier Ltd. All rights reserved.

Delay discounting of qualitatively different reinforcers in rats.

PubMed

Calvert, Amanda L; Green, Leonard; Myerson, Joel

2010-03-01

Humans discount larger delayed rewards less steeply than smaller rewards, whereas no such magnitude effect has been observed in rats (and pigeons). It remains possible that rats' discounting is sensitive to differences in the quality of the delayed reinforcer even though it is not sensitive to amount. To evaluate this possibility, Experiment 1 examined discounting of qualitatively different food reinforcers: highly preferred versus nonpreferred food pellets. Similarly, Experiment 2 examined discounting of highly preferred versus nonpreferred liquid reinforcers. In both experiments, an adjusting-amount procedure was used to determine the amount of immediate reinforcer that was judged to be of equal subjective value to the delayed reinforcer. The amount and quality of the delayed reinforcer were varied across conditions. Discounting was well described by a hyperbolic function, but no systematic effects of the quantity or the quality of the delayed reinforcer were observed.

Compensating measured intra-wafer ring oscillator stage delay with intra-wafer exposure dose corrections

NASA Astrophysics Data System (ADS)

Verhaegen, Staf; Nackaerts, Axel; Dusa, Mircea; Carpaij, Rene; Vandenberghe, Geert; Finders, Jo

2006-03-01

The purpose of this paper is to use measurements on real working devices to derive more information than typically measured by the classic line-width measurement techniques. The first part of the paper will discuss the principle of the measurements with a ring oscillator, a circuit used to measure the speed of elementary logic gates. These measurements contribute to the understanding of the exact timing dependencies in circuits, which is of utmost importance for the design and simulation of these circuits. When connecting an odd number of digital inverting stages in a ring, the circuit has no stable digital state but acts as an analog oscillator with the oscillation frequency dependent on the analog propagation delay of the signals through the stages. By varying some conditions during a litho step, the delay change caused by the process condition change can be measured very accurately. The response of the ring oscillator delay to exposure dose is measured and presented in this paper together with a comparison of measured line-width values of the poly gate lines. The second part of the paper will focus on improving the intra-wafer variation of the stage delay. A number of ring oscillators are put in a design at different slit and scan locations. 200mm wafers are processed with 48 full dies present. From the intra-wafer delay fingerprint and the dose sensitivity of the delay an intra-wafer dose correction, also called a dose recipe, is calculated. This dose recipe is used on the scanner to compensate for effects that are the root cause for the delay profile; including reticle and processing such as track, etch and annealing.

Enhanced equivalence class formation by the delay and relational functions of meaningful stimuli.

PubMed

Arntzen, Erik; Nartey, Richard K; Fields, Lanny

2015-05-01

Undergraduates in six groups of 10 attempted to form three 3-node 5-member equivalence classes (A → B → C → D → E) under the simultaneous protocol. In five of six groups, all stimuli were abstract shapes; in the PIC group, C stimuli were pictures with the remainder being abstract shapes. Before class formation, participants in the Identity-S and Identity-D groups were given preliminary training to form identity conditional discriminations with the C stimuli using simultaneous and 6 s delayed matching-to-sample procedures, respectively. In the Arbitrary-S and Arbitrary-D groups, before class formation, arbitrary conditional discriminations were formed between C and X stimuli using simultaneous and 6 s delayed matching-to-sample procedures, respectively. With no preliminary training, classes in the PIC and ABS groups were formed by 80% and 0% of participants, respectively. After preliminary training, class formation (yield) increased with delay, regardless of relational type. For each of the two delays, yield was slightly greater after forming arbitrary- instead of identity-relations. Yield was greatest, however, when a class contained a meaningful stimulus (PIC). During failed class formation, probes produced experimenter-defined relations, participant-defined relations, and unsystematic responding; delay, but not the relation type in preliminary training influenced relational and indeterminate responding. These results suggest how meaningful stimuli enhance equivalence class formation. © Society for the Experimental Analysis of Behavior.

Amplitude death and synchronized states in nonlinear time-delay systems coupled through mean-field diffusion

NASA Astrophysics Data System (ADS)

Banerjee, Tanmoy; Biswas, Debabrata

2013-12-01

We explore and experimentally demonstrate the phenomena of amplitude death (AD) and the corresponding transitions through synchronized states that lead to AD in coupled intrinsic time-delayed hyperchaotic oscillators interacting through mean-field diffusion. We identify a novel synchronization transition scenario leading to AD, namely transitions among AD, generalized anticipatory synchronization (GAS), complete synchronization (CS), and generalized lag synchronization (GLS). This transition is mediated by variation of the difference of intrinsic time-delays associated with the individual systems and has no analogue in non-delayed systems or coupled oscillators with coupling time-delay. We further show that, for equal intrinsic time-delays, increasing coupling strength results in a transition from the unsynchronized state to AD state via in-phase (complete) synchronized states. Using Krasovskii-Lyapunov theory, we derive the stability conditions that predict the parametric region of occurrence of GAS, GLS, and CS; also, using a linear stability analysis, we derive the condition of occurrence of AD. We use the error function of proper synchronization manifold and a modified form of the similarity function to provide the quantitative support to GLS and GAS. We demonstrate all the scenarios in an electronic circuit experiment; the experimental time-series, phase-plane plots, and generalized autocorrelation function computed from the experimental time series data are used to confirm the occurrence of all the phenomena in the coupled oscillators.

Evaluation of electrical propagation delay with cardiomyocytes by photosensitization reaction in vitro

NASA Astrophysics Data System (ADS)

Doi, Marika; Ogawa, Emiyu; Arai, Tsunenori

2017-02-01

In order to study cardiomyocyte electrical conduction damage by a photosensitization reaction (PR) mostly comes from outside of the cells in a few minutes after the PR, we studied propagation delay of contact action potential with cardiomyocyte by the PR. To determine appropriate PR condition for tachyarrhythmia ablation, a precise electrophysiological experiment in vitro has been preferable. We measured the contact action potential using a microelectrode array system of which information may be correct than conventional Ca2+ measurement. We investigated the propagation delays of an evoked potential to evaluate the electrical conduction damage by the PR. Rat cardiomyocytes were cultivated for 5-7 days on a dish with which 64 electrodes were patterned, in an incubator controlled to 37°C, 5% CO2. The following conditions were used for the PR: 40 μg/ml talapordfin sodium and 290 mW/cm2, 40-78 J/cm2 for an irradiation. A 2D map was obtained to visualize the propagation delays of the evoked potential. The propagation speed, which was calculated based on the measured propagation delays, was decreased by about 30-50% on average of all electrodes after the PR. Therefore, we think 2D propagation delays measurement of the evoked potential with contact action potential measuring system might be available to evaluate the acute electrical conduction damage of cardiomyocyte by the PR.

Young children's understanding of briefly versus extremely delayed images of the self: emergence of the autobiographical stance.

PubMed

Povinelli, D J; Simon, B B

1998-01-01

Eighty-eight young 3-, 4-, and 5-year-olds were scheduled for 2 testing sessions. On Visit 1, the children were videotaped playing a game while an experimenter covertly placed a large sticker on their head and covertly removed it after the game. One week later, the children were videotaped playing a different game. A sticker was again covertly placed on their heads. Half the children in each age group then observed the video from the previous week, whereas the other half observed the tape from 3 min earlier. Less than half of the 3-year-olds in both conditions reached up for the sticker. In contrast, the majority of 4- and 5-year-olds in the briefly delayed condition reached for the sticker, but few in the extremely delayed condition did so. By 4 years of age, children may have developed a causal understanding of the self's endurance through time.

Robustness analysis of uncertain dynamical neural networks with multiple time delays.

PubMed

Senan, Sibel

2015-10-01

This paper studies the problem of global robust asymptotic stability of the equilibrium point for the class of dynamical neural networks with multiple time delays with respect to the class of slope-bounded activation functions and in the presence of the uncertainties of system parameters of the considered neural network model. By using an appropriate Lyapunov functional and exploiting the properties of the homeomorphism mapping theorem, we derive a new sufficient condition for the existence, uniqueness and global robust asymptotic stability of the equilibrium point for the class of neural networks with multiple time delays. The obtained stability condition basically relies on testing some relationships imposed on the interconnection matrices of the neural system, which can be easily verified by using some certain properties of matrices. An instructive numerical example is also given to illustrate the applicability of our result and show the advantages of this new condition over the previously reported corresponding results. Copyright © 2015 Elsevier Ltd. All rights reserved.

Identification of neural structures involved in stuttering using vibrotactile feedback.

PubMed

Cheadle, Oliver; Sorger, Clarissa; Howell, Peter

Feedback delivered over auditory and vibratory afferent pathways has different effects on the fluency of people who stutter (PWS). These features were exploited to investigate the neural structures involved in stuttering. The speech signal vibrated locations on the body (vibrotactile feedback, VTF). Eleven PWS read passages under VTF and control (no-VTF) conditions. All combinations of vibration amplitude, synchronous or delayed VTF and vibrator position (hand, sternum or forehead) were presented. Control conditions were performed at the beginning, middle and end of test sessions. Stuttering rate, but not speaking rate, differed between the control and VTF conditions. Notably, speaking rate did not change between when VTF was delayed versus when it was synchronous in contrast with what happens with auditory feedback. This showed that cerebellar mechanisms, which are affected when auditory feedback is delayed, were not implicated in the fluency-enhancing effects of VTF, suggesting that there is a second fluency-enhancing mechanism. Copyright © 2018 Elsevier Inc. All rights reserved.

In the Blink of an I: On Delayed but Identical Subjective Reactions and Their Effect on Self-Interested Behavior.

PubMed

Pinel, Elizabeth C; Long, Anson E; Huneke, Mark

2015-01-01

People believe that they have shared an identical subjective experience--that they have I-shared--when they react identically and simultaneously to the same stimulus. Despite growing evidence for I-sharing, researchers have yet to ask whether simultaneity really makes a difference. We test the importance of simultaneity for I-sharing effects. Participants played prisoner's dilemma with someone who shared their subjective self, their objective self, or neither. Some participants learned this information immediately; others, after a short delay. Time delay decreased cooperation in the subjective similarity condition, but not in the objective similarity or neither conditions. These findings underscore the importance of simultaneity for I-sharing effects and highlight the implications of I-sharing for cooperation and self-interested behavior.

Output transformations and separation results for feedback linearisable delay systems

NASA Astrophysics Data System (ADS)

Cacace, F.; Conte, F.; Germani, A.

2018-04-01

The class of strict-feedback systems enjoys special properties that make it similar to linear systems. This paper proves that such a class is equivalent, under a change of coordinates, to the wider class of feedback linearisable systems with multiplicative input, when the multiplicative terms are functions of the measured variables only. We apply this result to the control problem of feedback linearisable nonlinear MIMO systems with input and/or output delays. In this way, we provide sufficient conditions under which a separation result holds for output feedback control and moreover a predictor-based controller exists. When these conditions are satisfied, we obtain that the existence of stabilising controllers for arbitrarily large delays in the input and/or the output can be proved for a wider class of systems than previously known.

Linear feedback stabilization of a dispersively monitored qubit

NASA Astrophysics Data System (ADS)

Patti, Taylor Lee; Chantasri, Areeya; García-Pintos, Luis Pedro; Jordan, Andrew N.; Dressel, Justin

2017-08-01

The state of a continuously monitored qubit evolves stochastically, exhibiting competition between coherent Hamiltonian dynamics and diffusive partial collapse dynamics that follow the measurement record. We couple these distinct types of dynamics together by linearly feeding the collected record for dispersive energy measurements directly back into a coherent Rabi drive amplitude. Such feedback turns the competition cooperative and effectively stabilizes the qubit state near a target state. We derive the conditions for obtaining such dispersive state stabilization and verify the stabilization conditions numerically. We include common experimental nonidealities, such as energy decay, environmental dephasing, detector efficiency, and feedback delay, and show that the feedback delay has the most significant negative effect on the feedback protocol. Setting the measurement collapse time scale to be long compared to the feedback delay yields the best stabilization.

Comparison of in-situ delay monitors for use in Adaptive Voltage Scaling

NASA Astrophysics Data System (ADS)

Pour Aryan, N.; Heiß, L.; Schmitt-Landsiedel, D.; Georgakos, G.; Wirnshofer, M.

2012-09-01

In Adaptive Voltage Scaling (AVS) the supply voltage of digital circuits is tuned according to the circuit's actual operating condition, which enables dynamic compensation to PVTA variations. By exploiting the excessive safety margins added in state-of-the-art worst-case designs considerable power saving is achieved. In our approach, the operating condition of the circuit is monitored by in-situ delay monitors. This paper presents different designs to implement the in-situ delay monitors capable of detecting late but still non-erroneous transitions, called Pre-Errors. The developed Pre-Error monitors are integrated in a 16 bit multiplier test circuit and the resulting Pre-Error AVS system is modeled by a Markov chain in order to determine the power saving potential of each Pre-Error detection approach.

Nomenclature of primary amenorrhea: A proposal document of the Japan Society of Obstetrics and Gynecology committee for the redefinition of primary amenorrhea.

PubMed

Shozu, Makio; Ishikawa, Hiroshi; Horikawa, Reiko; Sakakibara, Hideya; Izumi, Shun-Ichiro; Ohba, Takashi; Hirota, Yasushi; Ogata, Tsutomu; Osuga, Yutaka; Kugu, Koji

2017-11-01

The aim of this study was to provide medical terms to describe the condition of a girl who should be evaluated for primary amenorrhea in order to facilitate intervention at an appropriate time. We performed a literature and clinical guidelines search for recent practices with regard to menarche and discussed relevant cases that had been experienced by committee members. Additionally, we theoretically reviewed medical terms defined in the Glossary Book of Obstetrics and Gynecology in Japan (Japan Society of Obstetrics and Gynecology, 3rd edition). The committee for the redefinition of primary amenorrhea proposed the introduction of two terms and the deletion of one term that had been defined by the Japan Society of Obstetrics and Gynecology, instead of changing the age definition of primary amenorrhea. 'Delayed menarche' was introduced to describe a condition in which a girl has never experienced cyclic menstruation (menarche) by 15-17 years of age. 'Late menarche' was also introduced to describe a condition in which a girl has experienced menarche at 15 years of age or older. 'Delayed menstruation,' which was defined as a condition in which a girl experiences menarche at 15-18 years of age, was deleted. The new terms 'delayed menarche' and 'late menarche' were introduced, and the term 'delayed menstruation' was deleted. The new system might help in the early detection and appropriate treatment of primary amenorrhea. © 2017 Japan Society of Obstetrics and Gynecology.

The Evaluation and Treatment of Delayed Ejaculation.

PubMed

Shin, Daniel H; Spitz, Aaron

2014-10-01

Delayed ejaculation is a small but important subsection of ejaculatory dysfunction, with prevalence estimated at 1-4%. It is most commonly defined by DSM-IV-TR criteria, as "a persistent delay in, or absence of, orgasm in a male following a normal sexual excitement phase during sexual activity that the clinician, taking into account the person's age, judges to be adequate in focus, intensity, and duration." The pathophysiology of delayed ejaculation is related to disruptions in ejaculatory apparatus, nervous transmission, hormonal or neurochemical ejaculatory control, or psychosocial factors. To update the clinician on the evaluation and treatment of delayed ejaculation. The keywords "delayed ejaculation" and "retarded ejaculation" were utilized to search Pubmed for relevant publications. 319 results were generated from the search, and those publications judged relevant to the pathophysiology, epidemiology, evaluation, and treatment of delayed ejaculation were included in the review. 110 articles were ultimately selected for inclusion in this review. The evaluation of this condition requires a focused history and physical, which includes a detailed sexual history, examination of the genitalia, and inquiry into the status of the partner. Laboratory tests are aimed at the detection of abnormalities in the blood count, glucose level, hormone levels, or kidney function. If a correctable etiology is discovered, treatment is directed towards the reversal of this condition. In some cases, the delayed ejaculation may be a lifelong problem. Also, in some cases the etiology of the delayed ejaculation may be irreversible, such as in the case of age-related sensation loss or diabetes-related neuropathy. In these instances treatment may require a combination of behavioral modification, sexual therapy, or perhaps pharmaceutical drugs. Participation of the partner in therapy may sometimes be necessary. Future investigations will continue to elucidate the complex biological and psychosocial factors which contribute to delayed ejaculation, leading to more effective treatments. Shin DH and Spitz A. The evaluation and treatment of delayed ejaculation. Sex Med Rev 2014;2:121-133. Copyright © 2014 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Effects of wrapping time delays on fermentation characteristics of baled alfalfa silages

USDA-ARS?s Scientific Manuscript database

Baled silage is an attractive forage conservation approach for small and mid-sized dairy or beef producers, partly because it limits the risks associated with baling dry hay during wet or unstable weather conditions. Our objectives were to test the effects of delayed wrapping on silage fermentation,...

Analysis of backward differentiation formula for nonlinear differential-algebraic equations with 2 delays.

PubMed

Sun, Leping

2016-01-01

This paper is concerned with the backward differential formula or BDF methods for a class of nonlinear 2-delay differential algebraic equations. We obtain two sufficient conditions under which the methods are stable and asymptotically stable. At last, examples show that our methods are true.

The hybrid delay task: Can capuchin monkeys (Cebus apella) sustain a delay after an initial choice to do so?

PubMed Central

Paglieri, Fabio; Focaroli, Valentina; Bramlett, Jessica; Tierno, Valeria; McIntyre, Joseph M.; Addessi, Elsa; Evans, Theodore A.; Beran, Michael J.

2013-01-01

Choosing to wait for a better outcome (delay choice) and sustaining the delay prior to that outcome (delay maintenance) are both prerequisites for successful self control in intertemporal choices. However, most existing experimental methods test these skills in isolation from each other, and no significant correlation has been observed in performance across these tasks. In this study we introduce a new paradigm, the hybrid delay task, which combines an initial delay choice with a subsequent delay maintenance stage. This allows testing how often choosing to wait is paired with the actual ability to do so. We tested 18 capuchin monkeys (Cebus apella) from two laboratories in various conditions, and we found that subjects frequently chose the delayed reward but then failed to wait for it, due to poor delay maintenance. However, performance improved with experience and different behavioral responses for error correction were evident. These findings have far reaching implications: if such a high error rate was observed also in other species (possibly including Homo sapiens), this may indicate that delay choice tasks that make use of salient, prepotent stimuli do not reliably assess generalized self control, insofar as choosing to wait does not entail always being able to do so. PMID:23274585

The Sexual Discounting Task: HIV Risk Behavior and the Discounting of Delayed Sexual Rewards in Cocaine Dependence

PubMed Central

Johnson, Matthew W.; Bruner, Natalie R.

2011-01-01

Background Cocaine dependence is associated with high rates of sexual risk behavior and HIV infection. However, little is known about the responsible mechanism(s). Methods Cocaine-dependent individuals (N=62) completed a novel Sexual Discounting Task assessing decisions between immediate unprotected sex and delayed sex with a condom across four hypothetical partners: most (and least) likely to have a sexually transmitted infection (STI), and most (and least) sexually desirable; a real rewards money delay-discounting task, and self-reported sexual risk behavior using the HIV Risk-Taking Behavior Scale (HRBS). Results Sexual Discounting Task results were largely systematic and showed a strong effect of delay in decreasing condom use. Sexual discounting (preference for immediate unprotected sex) was significantly greater when making responses for partners judged least (compared to most) likely to have an STI, and for partners judged most (compared to least) desirable. Differences in sexual discounting were significant after controlling for differences in condom use (with no delay) between conditions. Greater discounting in 3 or the 4 Sexual Discounting Task conditions, but not in the money discounting task, was associated with greater self-reported sexual risk behavior as measured by the HRBS Conclusions Results suggest that delay is a critical variable strongly affecting HIV sexual risk behavior, and that the Sexual Discounting Task provides a clinically sensitive measure of this phenomenon that may address a variety of questions about HIV risk in future research. The wealth of behavioral and neurobiological data on delay discounting should be brought to bear on HIV education and prevention. PMID:22055012

Ignition Delay of Combustible Materials in Normoxic Equivalent Environments

NASA Technical Reports Server (NTRS)

McAllister, Sara; Fernandez-Pello, Carlos; Ruff, Gary; Urban, David

2009-01-01

Material flammability is an important factor in determining the pressure and composition (fraction of oxygen and nitrogen) of the atmosphere in the habitable volume of exploration vehicles and habitats. The method chosen in this work to quantify the flammability of a material is by its ease of ignition. The ignition delay time was defined as the time it takes a combustible material to ignite after it has been exposed to an external heat flux. Previous work in the Forced Ignition and Spread Test (FIST) apparatus has shown that the ignition delay in the currently proposed space exploration atmosphere (approximately 58.6 kPa and32% oxygen concentration) is reduced by 27% compared to the standard atmosphere used in the Space Shuttle and Space Station. In order to determine whether there is a safer environment in terms of material flammability, a series of piloted ignition delay tests using polymethylmethacrylate (PMMA) was conducted in the FIST apparatus to extend the work over a range of possible exploration atmospheres. The exploration atmospheres considered were the normoxic equivalents, i.e. reduced pressure conditions with a constant partial pressure of oxygen. The ignition delay time was seen to decrease as the pressure was reduced along the normoxic curve. The minimum ignition delay observed in the normoxic equivalent environments was nearly 30% lower than in standard atmospheric conditions. The ignition delay in the proposed exploration atmosphere is only slightly larger than this minimum. Interms of material flammability, normoxic environments with a higher pressure relative to the proposed pressure would be desired.

Stability and bifurcation analysis of a generalized scalar delay differential equation.

PubMed

Bhalekar, Sachin

2016-08-01

This paper deals with the stability and bifurcation analysis of a general form of equation D(α)x(t)=g(x(t),x(t-τ)) involving the derivative of order α ∈ (0, 1] and a constant delay τ ≥ 0. The stability of equilibrium points is presented in terms of the stability regions and critical surfaces. We provide a necessary condition to exist chaos in the system also. A wide range of delay differential equations involving a constant delay can be analyzed using the results proposed in this paper. The illustrative examples are provided to explain the theory.

Delayed mirror visual feedback presented using a novel mirror therapy system enhances cortical activation in healthy adults.

PubMed

Lee, Hsin-Min; Li, Ping-Chia; Fan, Shih-Chen

2015-07-11

Mirror visual feedback (MVF) generated in mirror therapy (MT) with a physical mirror promotes the recovery of hemiparetic limbs in patients with stroke, but is limited in that it cannot provide an asymmetric mode for bimanual coordination training. Here, we developed a novel MT system that can manipulate the MVF to resolve this issue. The aims of this pilot study were to examine the feasibility of delayed MVF on MT and to establish its effects on cortical activation in order to understand how it can be used for clinical applications in the future. Three conditions (no MVF, MVF, and 2-s delayed MVF) presented via our digital MT system were evaluated for their time-course effects on cortical activity by event-related desynchronization (ERD) of mu rhythm electroencephalography (EEG) during button presses in 18 healthy adults. Phasic ERD areas, defined as the areas of the relative ERD curve that were below the reference level and within -2-0 s (P0), 0-2 s (P1), and 2-4 s (P2) of the button press, were used. The overall (P0 to P2) and phasic ERD areas were higher when MVF was provided compared to when MVF was not provided for all EEG channels (C3, Cz, and C4). Phasic ERD areas in the P2 phase only increased during the delayed-MVF condition. Significant enhancement of cortical activation in the mirror neuron system and an increase in attention to the unseen limb may play major roles in the response to MVF during MT. In comparison to the no MVF condition, the higher phasic ERD areas that were observed during the P1 phase in the delayed-MVF condition indicate that the image of the still hand may have enhanced the cortical activation that occurred in response to the button press. This study is the first to achieve delayed MVF for upper-limb MT. Our approach confirms previous findings regarding the effects of MVF on cortical activation and contributes additional evidence supporting the use of this method in the future for upper-limb motor training in patients with stroke.

Time delay and long-range connection induced synchronization transitions in Newman-Watts small-world neuronal networks.

PubMed

Qian, Yu

2014-01-01

The synchronization transitions in Newman-Watts small-world neuronal networks (SWNNs) induced by time delay τ and long-range connection (LRC) probability P have been investigated by synchronization parameter and space-time plots. Four distinct parameter regions, that is, asynchronous region, transition region, synchronous region, and oscillatory region have been discovered at certain LRC probability P = 1.0 as time delay is increased. Interestingly, desynchronization is observed in oscillatory region. More importantly, we consider the spatiotemporal patterns obtained in delayed Newman-Watts SWNNs are the competition results between long-range drivings (LRDs) and neighboring interactions. In addition, for moderate time delay, the synchronization of neuronal network can be enhanced remarkably by increasing LRC probability. Furthermore, lag synchronization has been found between weak synchronization and complete synchronization as LRC probability P is a little less than 1.0. Finally, the two necessary conditions, moderate time delay and large numbers of LRCs, are exposed explicitly for synchronization in delayed Newman-Watts SWNNs.

Time Delay and Long-Range Connection Induced Synchronization Transitions in Newman-Watts Small-World Neuronal Networks

PubMed Central

Qian, Yu

2014-01-01

The synchronization transitions in Newman-Watts small-world neuronal networks (SWNNs) induced by time delay and long-range connection (LRC) probability have been investigated by synchronization parameter and space-time plots. Four distinct parameter regions, that is, asynchronous region, transition region, synchronous region, and oscillatory region have been discovered at certain LRC probability as time delay is increased. Interestingly, desynchronization is observed in oscillatory region. More importantly, we consider the spatiotemporal patterns obtained in delayed Newman-Watts SWNNs are the competition results between long-range drivings (LRDs) and neighboring interactions. In addition, for moderate time delay, the synchronization of neuronal network can be enhanced remarkably by increasing LRC probability. Furthermore, lag synchronization has been found between weak synchronization and complete synchronization as LRC probability is a little less than 1.0. Finally, the two necessary conditions, moderate time delay and large numbers of LRCs, are exposed explicitly for synchronization in delayed Newman-Watts SWNNs. PMID:24810595

Market-based control strategy for long-span structures considering the multi-time delay issue

NASA Astrophysics Data System (ADS)

Li, Hongnan; Song, Jianzhu; Li, Gang

2017-01-01

To solve the different time delays that exist in the control device installed on spatial structures, in this study, discrete analysis using a 2 N precise algorithm was selected to solve the multi-time-delay issue for long-span structures based on the market-based control (MBC) method. The concept of interval mixed energy was introduced from computational structural mechanics and optimal control research areas, and it translates the design of the MBC multi-time-delay controller into a solution for the segment matrix. This approach transforms the serial algorithm in time to parallel computing in space, greatly improving the solving efficiency and numerical stability. The designed controller is able to consider the issue of time delay with a linear controlling force combination and is especially effective for large time-delay conditions. A numerical example of a long-span structure was selected to demonstrate the effectiveness of the presented controller, and the time delay was found to have a significant impact on the results.

Minimizing delays in the Jordanian construction industry by adopting BIM technology

NASA Astrophysics Data System (ADS)

Btoush, M.; Harun, A. T.

2017-11-01

The Jordanian construction industry plays a significant role and contributes immensely to the gross domestic product (GDP) of the economy. However, the Jordanian public work and housing ministry and most industry players including engineers and contractors have reported that most of the projects experience delays which lead time and cost overruns, and extra efforts. The main causes of delays identified by researchers include poor scheduling and planning, change orders, site conditions, weather, late deliveries, incompetent technical staff. To address these challenges, the implementation of building information modelling (BIM) is paramount. This paper presents BIM as a powerful tool for reducing delays in Jordan construction projects. The paper focuses on two main parts; the first part involves the identification of the major causes of delays, and the second part is to accurately outline the roles and responsibilities of BIM specialist in construction projects. Finally, the paper matches the roles and responsibilities of BIM specialist and the causes of delays, and how the delays are addressed through BIM specialist.

Simulator study of the effect of visual-motion time delays on pilot tracking performance with an audio side task

NASA Technical Reports Server (NTRS)

Riley, D. R.; Miller, G. K., Jr.

1978-01-01

The effect of time delay was determined in the visual and motion cues in a flight simulator on pilot performance in tracking a target aircraft that was oscillating sinusoidally in altitude only. An audio side task was used to assure the subject was fully occupied at all times. The results indicate that, within the test grid employed, about the same acceptable time delay (250 msec) was obtained for a single aircraft (fighter type) by each of two subjects for both fixed-base and motion-base conditions. Acceptable time delay is defined as the largest amount of delay that can be inserted simultaneously into the visual and motion cues before performance degradation occurs. A statistical analysis of the data was made to establish this value of time delay. Audio side task provided quantitative data that documented the subject's work level.

Stability and Hopf Bifurcation in a HIV-1 System with Multitime Delays

NASA Astrophysics Data System (ADS)

Zhao, Lingyan; Liu, Haihong; Yan, Fang

In this paper, we propose a mathematical model for HIV-1 infection with three time delays. The model examines a viral-therapy for controlling infections by using an engineered virus to selectively eliminate infected cells. In our model, three time delays represent the latent period of pathogen virus, pathogen virus production period and recombinant (genetically modified) virus production period, respectively. Detailed theoretical analysis have demonstrated that the values of three delays can affect the stability of equilibrium solutions, can also lead to Hopf bifurcation and oscillated solutions of the system. Moreover, we give the conditions for the existence of stable positive equilibrium solution and Hopf bifurcation. Further, the properties of Hopf bifurcation are discussed. These theoretical results indicate that the delays play an important role in determining the dynamic behavior quantitatively. Therefore, it is a fact that delays are very important, which should not be missed in controlling HIV-1 infections.

Effects of time delays on stability and Hopf bifurcation in a fractional ring-structured network with arbitrary neurons

NASA Astrophysics Data System (ADS)

Huang, Chengdai; Cao, Jinde; Xiao, Min; Alsaedi, Ahmed; Hayat, Tasawar

2018-04-01

This paper is comprehensively concerned with the dynamics of a class of high-dimension fractional ring-structured neural networks with multiple time delays. Based on the associated characteristic equation, the sum of time delays is regarded as the bifurcation parameter, and some explicit conditions for describing delay-dependent stability and emergence of Hopf bifurcation of such networks are derived. It reveals that the stability and bifurcation heavily relies on the sum of time delays for the proposed networks, and the stability performance of such networks can be markedly improved by selecting carefully the sum of time delays. Moreover, it is further displayed that both the order and the number of neurons can extremely influence the stability and bifurcation of such networks. The obtained criteria enormously generalize and improve the existing work. Finally, numerical examples are presented to verify the efficiency of the theoretical results.

Distributed optimisation problem with communication delay and external disturbance

NASA Astrophysics Data System (ADS)

Tran, Ngoc-Tu; Xiao, Jiang-Wen; Wang, Yan-Wu; Yang, Wu

2017-12-01

This paper investigates the distributed optimisation problem for the multi-agent systems (MASs) with the simultaneous presence of external disturbance and the communication delay. To solve this problem, a two-step design scheme is introduced. In the first step, based on the internal model principle, the internal model term is constructed to compensate the disturbance asymptotically. In the second step, a distributed optimisation algorithm is designed to solve the distributed optimisation problem based on the MASs with the simultaneous presence of disturbance and communication delay. Moreover, in the proposed algorithm, each agent interacts with its neighbours through the connected topology and the delay occurs during the information exchange. By utilising Lyapunov-Krasovskii functional, the delay-dependent conditions are derived for both slowly and fast time-varying delay, respectively, to ensure the convergence of the algorithm to the optimal solution of the optimisation problem. Several numerical simulation examples are provided to illustrate the effectiveness of the theoretical results.

Exchanging the liquidity hypothesis: Delay discounting of money and self-relevant non-money rewards

PubMed Central

Stuppy-Sullivan, Allison M.; Tormohlen, Kayla N.; Yi, Richard

2015-01-01

Evidence that primary rewards (e.g., food and drugs of abuse) are discounted more than money is frequently attributed to money's high degree of liquidity, or exchangeability for many commodities. The present study provides some evidence against this liquidity hypothesis by contrasting delay discounting of monetary rewards (liquid) and non-monetary commodities (non-liquid) that are self-relevant and utility-matched. Ninety-seven (97) undergraduate students initially completed a conventional binary-choice delay discounting of money task. Participants returned one week later and completed a self-relevant commodity delay discounting task. Both conventional hypothesis testing and more-conservative tests of statistical equivalence revealed correspondence in rate of delay discounting of money and self-relevant commodities, and in one magnitude condition, less discounting for the latter. The present results indicate that liquidity of money cannot fully account for the lower rate of delay discounting compared to non-money rewards. PMID:26556504

When the Battle is Lost and Won: Delayed Chest Closure After Bilateral Lung Transplantation.

PubMed

Soresi, Simona; Sabashnikov, Anton; Weymann, Alexander; Zeriouh, Mohamed; Simon, André R; Popov, Aron-Frederik

2015-10-12

In this article we summarize benefits of delayed chest closure strategy in lung transplantation, addressing indications, different surgical techniques, and additional perioperative treatment. Delayed chest closure seems to be a valuable and safe strategy in managing patients with various conditions after lung transplantation, such as instable hemodynamics, need for high respiratory pressures, coagulopathy, and size mismatch. Therefore, this approach should be considered in lung transplant centers to give patients time to recover before the chest is closed.

The use of picture prompts and prompt delay to teach receptive labeling.

PubMed

Vedora, Joseph; Barry, Tiffany

2016-12-01

The current study extended research on picture prompts by using them with a progressive prompt delay to teach receptive labeling of pictures to 2 teenagers with autism. The procedure differed from prior research because the auditory stimulus was not presented or was presented only once during the picture-prompt condition. The results indicated that the combination of picture prompts and prompt delay was effective, although 1 participant required a procedural modification. © 2016 Society for the Experimental Analysis of Behavior.

Interval oscillation criteria for second-order forced impulsive delay differential equations with damping term.

PubMed

Thandapani, Ethiraju; Kannan, Manju; Pinelas, Sandra

2016-01-01

In this paper, we present some sufficient conditions for the oscillation of all solutions of a second order forced impulsive delay differential equation with damping term. Three factors-impulse, delay and damping that affect the interval qualitative properties of solutions of equations are taken into account together. The results obtained in this paper extend and generalize some of the the known results for forced impulsive differential equations. An example is provided to illustrate the main result.

The benefits of Tai Chi and brisk walking for cognitive function and fitness in older adults

PubMed Central

Ji, Zhiguang; Feng, Tian; Liu, Xiaolei; You, Yihong; Meng, Fanying; Wang, Ruoqing; Lu, Jialing

2017-01-01

The purpose of this study was to investigate the benefits of exercises with different cognitive demands for cognitive functions (Executive and non-Executive) in healthy older adults. A cross-sectional design was adopted. In total, 84 healthy older adults were enrolled in the study. They were categorized into the Tai Chi group (TG), the brisk walking group (BG) or the control group (CG). Each participant performed the Stroop task and a digit comparison task. The Stroop task included the following three conditions: a naming condition, an inhibition condition and an executive condition. There were two experimental conditions in the digit comparison task: the non-delay condition and the delay condition. The results indicated that participants of the TG and BG revealed significant better performance than the CG in the executive condition of cognitive tasks and fitness. There was no significant difference of reaction time (RT) and accuracy rate in the inhibition and delay conditions of cognitive tasks and fitness between the TG and BG. The TG showed shorter reaction time in the naming and the executive conditions, and more accurate in the inhibition conditions than the BG. These findings demonstrated that regular participation in brisk walking and Tai Chi have significant beneficial effects on executive function and fitness. However, due to the high cognitive demands of the exercise, Tai Chi benefit cognitive functions (Executive and non-Executive) in older adults more than brisk walking does. Further studies should research the underlying mechanisms at the behavioural and neuroelectric levels, providing more evidence to explain the effect of high-cognitive demands exercise on different processing levels of cognition. PMID:29062610

East Indian Sandalwood and alpha-santalol odor increase physiological and self-rated arousal in humans.

PubMed

Heuberger, Eva; Hongratanaworakit, Tapanee; Buchbauer, Gerhard

2006-07-01

In Ayurvedic medicine, East Indian Sandalwood is an important remedy for the treatment of both somatic and mental disorders. In this investigation, the effects of inhalation of East Indian Sandalwood essential oil and its main compound, alpha-santalol, on human physiological parameters (blood oxygen saturation, respiration rate, eye-blink rate, pulse rate, skin conductance, skin temperature, surface electromyogram, and blood pressure) and self-ratings of arousal (alertness, attentiveness, calmness, mood, relaxation and vigor) were studied in healthy volunteers. Compared to either an odorless placebo or alpha-santalol, Sandalwood oil elevated pulse rate, skin conductance level, and systolic blood pressure. alpha-Santalol, however, elicited higher ratings of attentiveness and mood than did Sandalwood oil or the placebo. Correlation analyses revealed that these effects are mainly due to perceived odor quality. The results suggest a relation between differences in perceived odor quality and differences in arousal level.

Gyroscope-driven mouse pointer with an EMOTIV® EEG headset and data analysis based on Empirical Mode Decomposition.

PubMed

Rosas-Cholula, Gerardo; Ramirez-Cortes, Juan Manuel; Alarcon-Aquino, Vicente; Gomez-Gil, Pilar; Rangel-Magdaleno, Jose de Jesus; Reyes-Garcia, Carlos

2013-08-14

This paper presents a project on the development of a cursor control emulating the typical operations of a computer-mouse, using gyroscope and eye-blinking electromyographic signals which are obtained through a commercial 16-electrode wireless headset, recently released by Emotiv. The cursor position is controlled using information from a gyroscope included in the headset. The clicks are generated through the user's blinking with an adequate detection procedure based on the spectral-like technique called Empirical Mode Decomposition (EMD). EMD is proposed as a simple and quick computational tool, yet effective, aimed to artifact reduction from head movements as well as a method to detect blinking signals for mouse control. Kalman filter is used as state estimator for mouse position control and jitter removal. The detection rate obtained in average was 94.9%. Experimental setup and some obtained results are presented.

Gyroscope-Driven Mouse Pointer with an EMOTIV® EEG Headset and Data Analysis Based on Empirical Mode Decomposition

PubMed Central

Rosas-Cholula, Gerardo; Ramirez-Cortes, Juan Manuel; Alarcon-Aquino, Vicente; Gomez-Gil, Pilar; Rangel-Magdaleno, Jose de Jesus; Reyes-Garcia, Carlos

2013-01-01

This paper presents a project on the development of a cursor control emulating the typical operations of a computer-mouse, using gyroscope and eye-blinking electromyographic signals which are obtained through a commercial 16-electrode wireless headset, recently released by Emotiv. The cursor position is controlled using information from a gyroscope included in the headset. The clicks are generated through the user's blinking with an adequate detection procedure based on the spectral-like technique called Empirical Mode Decomposition (EMD). EMD is proposed as a simple and quick computational tool, yet effective, aimed to artifact reduction from head movements as well as a method to detect blinking signals for mouse control. Kalman filter is used as state estimator for mouse position control and jitter removal. The detection rate obtained in average was 94.9%. Experimental setup and some obtained results are presented. PMID:23948873

Feeling worse to feel better: pain-offset relief simultaneously stimulates positive affect and reduces negative affect.

PubMed

Franklin, Joseph C; Lee, Kent M; Hanna, Eleanor K; Prinstein, Mitchell J

2013-04-01

Although pain itself induces negative affect, the removal (or offset) of pain induces a powerful state of relief. Despite being implicated in a wide range of psychological and behavioral phenomena, relief remains a poorly understood emotion. In particular, some theorists associate relief with increased positive affect, whereas others associate relief with diminished negative affect. In the present study, we examined the affective nature of relief in a pain-offset paradigm with psychophysiological measures that were specific to negative valence (startle eyeblink reactivity) and positive valence (startle postauricular reactivity). Results revealed that pain offset simultaneously stimulates positive affect and diminishes negative affect for at least several seconds. Results also indicated that pain intensity differentially affects the positive and negative valence aspects of relief. These findings clarify the affective nature of relief and provide insight into why people engage in both normal and abnormal behaviors associated with relief.

Delay discounting and response disinhibition under acute experimental stress in women with borderline personality disorder and adult attention deficit hyperactivity disorder.

PubMed

Krause-Utz, A; Cackowski, S; Daffner, S; Sobanski, Esther; Plichta, Michael M; Bohus, M; Ende, G; Schmahl, C

2016-11-01

Impulsivity is a core feature of borderline personality disorder (BPD) and attention deficit hyperactivity disorder (ADHD). In BPD, impulsive behavior primarily occurs under acute stress; impulse control deficits under non-stress conditions may be partly related to co-morbid ADHD. We aimed to investigate whether acute experimental stress has an impact on self-reported impulsivity, response inhibition (action withholding, action cancelation) and delay discounting in BPD compared to ADHD. Thirty female BPD patients, 28 female ADHD patients (excluding patients with co-morbid BPD and ADHD), and 30 female healthy controls (HC) completed self-reports and behavioral measures of impulsivity (IMT, assessing action withholding; GoStop, measuring action cancelation, Delay Discounting Task) under baseline conditions and after an experimental stress induction (Mannheim Multicomponent Stress Test). Both patient groups reported higher impulsivity than HC, ADHD reported higher trait impulsivity than BPD. On the IMT, ADHD showed significant action-withholding deficits under both conditions, while BPD performed significantly worse than HC under stress. In BPD but not ADHD and HC, action-withholding deficits (IMT) were significantly increased under stress compared to baseline, while no group/stress effects were found for action cancelation (GoStop). Delay discounting was significantly more pronounced in BPD than in HC (no stress effect was found). In BPD, behavioral deficits in action withholding (but not in action cancelation) appear to be influenced by acute experimental stress. Delay discounting seems to be a general feature of BPD, independent of co-morbid ADHD and acute stress, possibly underlying typical expressions of behavioral impulsivity in the disorder.