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At least 217 records · Page 12Linked to original sources
PubMed2000

Psychological stress, drug-related cues and cocaine craving.

RATIONALE: While several environmental situations may produce cocaine craving, there is little research on whether patterns of drug cue reactivity are similar across different environmental situations. OBJECTIVE: This study examined whether two different environmental situations, psychological stress and drug cues, produce similar or varying patterns of cue reactivity in 20 cocaine dependent individuals. METHODS: All subjects participated in a single laboratory session and were exposed to stress, drug cues and neutral-relaxing imagery conditions. Cocaine and alcohol craving, emotion state ratings, subjective anxiety, heart rate and salivary cortisol measures were assessed. RESULTS: Significant increases in cocaine and alcohol craving were observed with stress and drug cues imagery but not with neutral-relaxing imagery. In addition, stress and drug cues situations produced similar increases in subjective anxiety, heart rate and salivary cortisol levels. Significant increases in negative emotion ratings and decreases in positive emotion ratings were found for stress and drug cues conditions as compared to the neutral condition. CONCLUSIONS: The findings indicate that a similar and comparable pattern of cue reactivity is induced by stress and drug cue manipulations. Furthermore, the comparable increases in subjective anxiety and negative affect observed with stress-induced and drug cue-induced craving provides support for the negative reinforcement model of drug craving and relapse. The negative affectivity co-occurring with the craving state appears to be an important target in the development of new treatments for cocaine dependence.

Adult↗
PubMed2001

Interaction of vibrational and visual cues in parasitoid host location.

Female parasitoids are guided by multisensory information during host finding. Individual cues are used in an interactive or a hierarchical manner according to the relative importance on the spatial scale of their effect. Unlike most studies that concentrate on single cues, the present paper investigates the interaction of two physical cues. The interaction of mechanosensory and visual cues was studied in the pupal parasitoid Pimpla turionellae (Hymenoptera: Ichneumonidae). This species uses, amongst other senses, vibrational sounding (echolocation in a solid substrate) to find its mainly endophytic hosts. Location and frequency of ovipositor insertions were scored on cylindrical plant stem models with single or combined cues. Single-cue experiments show that parasitoids use both visual and mechanosensory cues and achieve a similar precision of host location with either cue. The combination of vision and vibrational sounding increased the precision of host location by a factor of approximately two to three. We conclude that the two senses interact, resulting in an additive accuracy. Neither the visual nor the mechanosensory cue was favored when offered adjacent to each other on the same stem model. On the investigated spatial scale, both physical cues are used and seem to be equally important for host location in this species.

Animals↗
PubMed1993

To see or not to see: the effects of visible and invisible cues on line bisection judgements in unilateral neglect.

Patients with left unilateral neglect and matched controls were tested in two experiments to examine the effects of lateralized cues on line bisection judgements. Unlike previous studies in which letter or number cues were placed beyond the endpoint(s) of each line, we adopted a procedure which maintained the perceptual point of balance in the horizontal axis of each line. We also related the cueing task more closely to the act of bisection by requiring subjects to place a small mark in direct alignment with the endpoint(s) of each line. In the first experiment, it was found that, for controls, the presence or absence of visible lateralized cues did not differentially affect the magnitude of bisection errors. However, the magnitude of bisection errors made by neglect patients was significantly reduced (and reversed) in the presence of a visible left-sided cue, but remained well to the right of the midpoint in the absence of such cues. In a second experiment, subjects engaged in an otherwise identical cueing procedure, except that no visible marks appeared on the stimulus lines. Neither subject group was affected by the presence or absence of right-sided cues. However, the presence of left-sided cues again reduced the magnitude of bisection errors in neglect patients, but not in controls. These results indicate that the extent of the attentional bias exhibited by neglect patients can be ameliorated even in the absence of lateralized visible cues.

Aged↗
PubMed1995

Speed discrimination of motion-in-depth using binocular cues.

Although it is well known that motion-in-depth can be detected using binocular cues, it is not known whether those cues can be used to judge the speed of an object moving in depth. There are at least two possible binocular cues that could be used by the visual system to calculate three dimensional (3-D) speed: the rate of change of binocular disparity, or a comparison of the speeds of motion in the two eyes. We tested which of these cues is used to discriminate the speed of motion-in-depth. First, speed discrimination was measured for a dot moving away from the observer in depth (along the z-axis) and for a random dot stereogram in which a central square moved away from the observer in depth. These stimuli contained both disparity and monocular motion cues. Speed discrimination thresholds were as good for 3-D motion as for monocular sideways motion. Second, a dynamic random dot stereogram (in which the random dot pattern was replaced by a new dot pattern every frame) was used to remove consistent monocular cues. 3-D speed discrimination was now very poor, suggesting that the rate of change of disparity is not a good cue for 3-D speed. Finally, we tested whether observers were able to use the monocular motion cue from one eye to perform the speed discrimination task, or whether there had to be a comparison of the two eyes' monocular cues. By adding a small x-axis velocity component (with random direction) to the z-axis motion, it was possible to disrupt the monocular motion signals without altering the speed of the motion in 3-D. This manipulation did not disrupt the observers' performance, suggesting that monocular speed cues were not being used independently but that there was a comparison of monocular motion signals from the two eyes.

Cues↗
PubMed1996

The relative efficacy of cues for two-dimensional shape perception.

The visual system uses a variety of cues for form perception, including motion, color, binocular disparity, texture, and luminance. Physiological evidence suggests that these cues are processed by different neural mechanisms. Do the cues processed by some mechanisms convey any advantage for form perception when compared to cues processed by another? In response to this question we assessed the relative efficiency of several cues in conveying two-dimensional form from background noise. For the sake of comparison, every cue type used the same experimental design and stimulus set. Our results confirm that movement is one of the most efficient cues for shape perception. Also, a simple transient cue (an instantaneous flashing on or off) is equally useful. In comparison, local dot density (a type of texture cue) was the least efficient. The efficiencies of most other cues, such as color, stereopsis, and relative movement in noise, were conspicuously similar.

Adult↗
PubMed2006

Integration of force and position cues for shape perception through active touch.

This article systematically explores cue integration within active touch. Our research builds upon a recently made distinction between position and force cues for haptic shape perception: when sliding a finger across a bumpy surface, the finger follows the surface geometry (position cue). At the same time, the finger is exposed to forces related to the slope of the surface (force cue). Experiment 1 independently varied force and position cues to the curvature of 3D arches. Perceived curvature could be well described as a weighted average of the two cues. Experiment 2 found more weight of the position cue for more convex high arches and higher weight of the force cue for less convex shallow arches--probably mediated through a change in relative cue reliability. Both findings are in good agreement with the maximum-likelihood estimation (MLE) model for cue integration and, thus, carry this model over to the domain of active haptic perception.

Adult↗
PubMed2004

Modulations of the visual N1 component of event-related potentials by central and peripheral cueing.

OBJECTIVE: The aim of this study is to investigate the effects of the central and peripheral cueing on N1 component of the event-related potentials (ERPs) and the time course of these effects. METHODS: ERPs were recorded while participants performed a discrimination task on the height of target bars, which were presented after informative-central, informative-peripheral or uninformative-peripheral cues with stimulus onset asynchronies (SOAs) of 100, 300, 500 or 700 ms. RESULTS: Peripheral cues (informative and uninformative) elicited stronger effects of cue validity on N1 300 ms after cue onset, whereas central cues led to a more sustained validity effect on N1, with later stronger effects, at 500 ms SOA. CONCLUSIONS: The present data showed that central and peripheral cues affected to the level of processing reflected by the N1 component, but there were differences in the time course of these effects. Attentional orienting in response to central cueing resulted in a sustained validity effect on N1, relative to the more transitory activation of the process reflected by the N1 validity effect in this peripheral cueing task. SIGNIFICANCE: This study provides a detailed within-subject analysis of the time course of the effects of central and peripheral cueing on N1.

Adult↗
PubMed2006

Cue validity modulates the neural correlates of covert endogenous orienting of attention in parietal and frontal cortex.

Parietal brain regions have been implicated in reorienting of visuospatial attention in location-cueing paradigms when misleading advance information is provided in form of a spatially invalid cue. The difference in reaction times to invalidly and validly cued targets is termed the "validity effect" and used as a behavioral measure for attentional reorienting. Behavioral studies suggest that the magnitude of the validity effect depends on the ratio of validly to invalidly cued targets (termed cue validity), i.e., on the amount of top-down information provided. Using fMRI, we investigated the effects of a cue validity manipulation upon the neural mechanisms underlying attentional reorienting using valid and invalid spatial cues in the context of 90% and 60% cue validity, respectively. We hypothesized that increased parietal activation would be elicited when subjects need to reorient their attention in a context of high cue validity. Behaviorally, subjects showed significantly higher validity effects in the high as compared to the low cue validity condition, indicating slower reorienting. The neuroimaging data revealed higher activation of right inferior parietal and right frontal cortex in the 90% than in the 60% cue validity condition. We conclude that the amount of top-down information provided by predictive cues influences the neural correlates of reorienting of visuospatial attention by modulating activation of a right fronto-parietal attentional network.

Adult↗
PubMed2004

Cue reactivity in smokers: the effects of perceived cigarette availability and gender.

We examined the effects of perceived cigarette availability and gender on smoking cue reactivity. Smokers were exposed to smoking cues (smoking paraphernalia) and control cues whilst their subjective and physiological responses were measured. Perceived cigarette availability was manipulated on a between-subjects basis before cue exposure. Relative to control cues, smoking cues evoked increases in the level of skin conductance in all participants. Cigarette craving was also increased in the presence of smoking cues, but only in female participants. Perceived cigarette availability had no effect on these responses. Participants also showed salivary reactivity to smoking cues, with males showing a decrease in salivation, and females showing an increase, but only when cigarettes were perceived as unavailable. These results suggest that perceived cigarette availability may not influence craving and skin conductance reactivity to smoking cues in minimally dependent smokers who are not nicotine deprived. In addition, the present data suggest that there are important gender differences in craving reactivity to smoking cues.

Adult↗
PubMed2005

Integrating visual cues for motor control: a matter of time.

The visual system continuously integrates multiple sensory cues to help plan and control everyday motor tasks. We quantified how subjects integrated monocular cues (contour and texture) and binocular cues (disparity and vergence) about 3D surface orientation throughout an object placement task and found that binocular cues contributed more to online control than planning. A temporal analysis of corrective responses to stimulus perturbations revealed that the visuomotor system processes binocular cues faster than monocular cues. This suggests that binocular cues dominated online control because they were available sooner, thus affecting a larger proportion of the movement. This was consistent with our finding that the relative influence of binocular information was higher for short-duration movements than long-duration movements. A motor control model that optimally integrates cues with different delays accounts for our findings and shows that cue integration for motor control depends in part on the time course of cue processing.

Cues↗
PubMed2006

Cue combination in a combined feature contrast detection and figure identification task.

Target figures defined by feature contrast in spatial frequency, orientation or both cues had to be detected in Gabor random fields and their shape had to be identified in a dual task paradigm. Performance improved with increasing feature contrast and was strongly correlated among both tasks. Subjects performed significantly better with combined cues than with single cues. The improvement due to cue summation was stronger than predicted by the assumption of independent feature specific mechanisms, and increased with the performance level achieved with single cues until it was limited by ceiling effects. Further, cue summation was also strongly correlated among tasks: when there was benefit due to the additional cue in feature contrast detection, there was also benefit in figure identification. For the same performance level achieved with single cues, cue summation was generally larger in figure identification than in feature contrast detection, indicating more benefit when processes of shape and surface formation are involved. Our results suggest that cue combination improves spatial form completion and figure-ground segregation in noisy environments, and therefore leads to more stable object vision.

Adult↗
PubMed2002

Effects of visible and invisible cueing on line bisection and Landmark performance in hemispatial neglect.

A total of 12 patients with hemispatial neglect (and two control groups) were tested to examine the effects of lateralized cues on line bisection and Landmark judgements. The experiment was designed to investigate whether bisection and landmark biases induced by cueing are simply a result of a direct perceptual lengthening of the cued part of the line caused by the fact that the cue is visible, thus creating a composite 'line plus cue' or whether cueing indeed induces an attentional bias. Secondly, earlier work by Harvey et al. [Harvey M, Milner AD, Roberts RC. An investigation of hemispatial neglect using the landmark task, Brain and Cognition 1995; 27: 59-78] has shown that in neglect patients cues work by inducing orientational biases rather than via the alteration of subjective length perception. An attempt was made to replicate this finding and extend it to cues that are not physically present. The bisection data clearly showed that cues bias attention rather than work via a direct lengthening of the line: both visible and invisible cues biased bisection performance equally well. The Landmark data, however, revealed much less clear-cut results and we failed to repeat the earlier observation by Harvey et al. that cues induce orientational biases. Even when the neglect patients were categorised into premotor and perceptual categories a clear effect failed to emerge. It is hypothesised that the earlier reported effect may be linked to neglect severity rather than to perceptual type neglect.

Aged↗
PubMed2000

Effects of visible and invisible cueing procedures on perceptual judgments in young and elderly subjects.

Healthy subjects were tested in two experiments to examine the effects of lateralized cues on line bisection and landmark judgments. The studies were designed to investigate whether bisection and landmark biases induced by cueing are simply a result of a direct perceptual lengthening of the cued part of the line caused by the fact that the cue is visible, thus creating a composite 'line plus cue' or whether cueing induces an attentional bias operating on judgments of spatial extent by either reducing the magnitude of the parts of the stimulus receiving 'less' attention or magnifying those parts receiving 'more'. Lateralized cues were either visible letter cues or invisible marks drawn with a leadless pencil either by the subject him/herself (Experiment 1) or the experimenter (Experiment 2). Comparable to a previous study (Mattingley, Pierson, Bradshaw, Phillips and Bradshaw, 1993, Neuropsychologia, 31, 1201-1215), the first experiment showed that only visible cues affected line bisection and landmark judgments thus favouring the perceptual explanation. The second study, however, revealed bisection and judgment biases for invisible as well as visible cues with the attended part of the line appearing subjectively longer. These results indicate that attentional modulations can increase the salience of a line in a similar vein to physical changes. It seems likely that the requirement of a motor response in Experiment 1 cancelled out all attentional properties supposedly induced by placing that invisible cue.

Adult↗
PubMed1998

A comparison of visual- and response-generated cues in a spatial DMTS task for rats.

In an attempt to clarify the nature of the memory cues used in a spatial, working memory task, rats were tested in a two-choice water maze. Each trial consisted of an information run, which forced the rat to the correct choice compartment, a retention period, and a test run. A response-associated cue condition, in which the relevant cue was the direction of the turn in the information run, was compared to a visual cue condition in which the animal had to remember whether the escape platform had been in the light or dark compartment. Of the subjects supplied with either visual or response-associated cues, the subjects allowed to employ response-associated cues did better, but the best performance occurred when both cues were available. When rats trained with both cues present were forced to choose between cues, they stopped using either and reverted to making a preferred right or left turn. The results support the idea that rats can form integrated, relational-cue memories which, in some circumstances, prove a hindrance to performance.

Animals↗
PubMed1998

An acute dose of nicotine enhances cue-induced cocaine craving.

The present study examined whether the active component in tobacco, nicotine, can modulate cocaine craving in patients with a history of smoking crack cocaine when exposed to crack cocaine related environmental cues. Twenty patients, all cigarette smokers, were randomly assigned to nicotine (two 22 mg transdermal patches) or placebo in a single-dose, placebo-controlled, crossover, double-blind study. Craving and anxiety were measured before and after cocaine cues with visual analog scales for desire to use cocaine and mood. Skin conductance and skin temperature were recorded before and during cocaine cues. Following exposure to cocaine cues, all patients reported an increase in cocaine craving and anxiety relative to the pre-cue measures. Cue exposure also produced an increase in skin conductance and decrease in skin temperature. The cue-induced increase in cocaine craving was strongly enhanced by nicotine, while the increase in anxiety was slightly augmented. Cue-induced skin conductance and temperature responses were unaffected by nicotine. These findings show that cue-induced cocaine craving is enhanced by nicotine. This occurred in the absence of any tobacco smoking-related cues, suggesting that nicotine may have direct psychopharmacological effects on conditioned cocaine craving.

Adult↗
PubMed2000

Rats with hippocampal lesions learn about allocentric place cues in a non-navigational task.

Hippocampal-lesioned rats (HPC) and sham controls (SH) learned constant-negative visual discriminations among scenes in a Y-maze. Any arm could be start arm for a trial. Two choice scenes ("constant" and "variable") were shown in the other arms. In Experiment 1, each problem had 2 constants. One or the other constant appeared on every trial, and the variable changed every trial; choosing the variable was rewarded. There were 4 problem types. Each constant might be always in a given direction from the start arm (added egocentric [Ego] cue), always in a given maze arm (added allocentric [Allo] cue), both, or neither. SH rats' visual learning was enhanced by Ego and by Allo cues. HPC rats' visual learning was enhanced by Ego cues, and by Allo cues, but only if there was no Ego cue. Experiment 2 confirmed that Allo cues helped HPC rats as much as SH, in the absence of Ego cues. Rats with HPC lesions can learn about allocentric place cues when navigation and idiothetic cue control are not required.

Animals↗
PubMed2002

Outcome and cue properties modulate blocking.

Participants saw a series of situations in which a cue (a light appearing at a certain position) could be followed by an outcome (a drawing of a tank that exploded) and were afterwards asked to rate the likelihood of the outcome in the presence of the cue. In Experiments 1 and 2, the compound cues AT and KL were always followed by the outcome (AT+, KL+). During an elemental phase that either preceded or followed the compound phase, Cue A was also paired with the outcome (A+). Cue T elicited a lower rating than Cues K and L when cues were described as being weapons but not when the cues were said to be indicators. The magnitude of this blocking effect was also influenced by whether the outcome occurred to a maximal or submaximal extent. Experiment 3 replicated the effect of cue instructions on blocking (A+, AT+) but showed that cue instructions had no impact on reduced overshadowing (B-, BT+). The results shed new light on previous findings and support probabilistic contrast models of human contingency judgements.

Cues↗
PubMed2004

Learning about cues that prevent an outcome: conditioned inhibition and differential inhibition in human predictive learning.

Summation tests were used to assess whether participants in a human predictive judgement task learned that some cues (foods) prevented the occurrence of the outcome (migraine). In three experiments the preventative effect of a conditioned inhibitor, I, trained in the design, P+, PI-, I-, was stronger than that of a negative control cue, N, that had been presented alone with the same frequency and simply predicted no outcome. This control cue, N, also passed the summation test when compared to a novel control cue. Experiments 2 and 3 examined whether the latter negative control effect was attributable to differential inhibition. Manipulations designed to alter context learning and the magnitude of the negative contingency did not affect the properties of the negative control cue. Thus, these experiments did not support the possibility that a cue given simple negative training acquires differential inhibition. Regardless of the mechanism underlying the negative control effect, the consistent finding that the conditioned inhibition cue, I, reduced prediction of the outcome more than did the negative control cue, N, provides evidence for true conditioned inhibition whose acquisition requires co-occurrence of the preventative cue with a positive training cue.

Affect↗