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PubMed2006

Disparity and shading cues cooperate for surface interpolation.

In two experiments, we tested whether disparity and shading cues cooperated for surface interpolation. Observers adjusted a probe dot to/lie on a surface specified either by a sparse disparity field, a continuous stereo shading or monocular shading gradient, or both cues. Observers' adjustments were very consistent with disparity information but their adjustments were much more variable with shading information. However, observers significantly improved their precision when both cues were present, relative to when only disparity information was present. These results cannot be explained by assuming that separate modules analyze disparity and shading information, even if observers optimally combined these cues. Rather, we attribute this improvement to a process through which the shading gradient constrains the disparity field in regions where disparities cannot be directly measured. This cooperative process may be based on the natural covariation existing between these cues produced by the retinal projection of smooth surfaces.

Adult↗
PubMed2001

Different patterns of human discrimination learning for two interaural cues to sound-source location.

Two of the primary cues used to localize the sources of sounds are interaural level differences (ILDs) and interaural time differences (ITDs). We conducted two experiments to explore how practice affects the human discrimination of values of ILDs and ongoing ITDs presented over headphones. We measured discrimination thresholds of 13 to 32 naive listeners in a variety of conditions during a pretest and again, 2 weeks later, during a posttest. Between those two tests, we trained a subset of listeners 1 h per day for 9 days on a single ILD or ITD condition. Listeners improved on both ILD and ITD discrimination. Improvement was initially rapid for both cue types and appeared to generalize broadly across conditions, indicating conceptual or procedural learning. A subsequent slower-improvement stage, which occurred solely for the ILD cue, only affected conditions with the trained stimulus frequency, suggesting that stimulus processing had fundamentally changed. These different learning patterns indicate that practice affects the attention to, or low-level encoding of, ILDs and ITDs at sites at which the two cue types are processed separately. Thus, these data reveal differences in the effect of practice on ILD and ITD discrimination, and provide insight into the encoding of these two cues to sound-source location in humans.

Acoustic Stimulation↗
PubMed2005

Complex magnetic fields enable static magnetic field cue use for rats in radial maze tasks.

Male Wistar rats were trained in an eight-arm radial maze task (two sessions per day, delayed-non-matching-to-sample) that included an intramaze static magnetic field "cue" (185 microT) specific to the entrance point of one of the arms. Rats were exposed daily for 60 min to a complex magnetic field waveform (theta-burst pattern, 200-500 nT), presented with several different interstimulus intervals (ISIs), either immediately following training sessions or immediately preceding testing sessions. Application of the theta-burst stimulus with a 4000 ms ISI significantly improved the rats' memory for the arm of the radial maze whose position was indicated by the presence of a static magnetic field cue. Reference memory errors were homogeneously distributed among all eight arms of the maze for sham-exposed rats, and among the other seven arms of the maze for complex magnetic field-treated rats. These results suggest that static magnetic field cues may be salient orienting cues even in a microenvironment such as a radial maze, but their use as a cue during maze learning in rats is dependent on whole-body application of a specific time-varying complex magnetic field.

Animals↗
PubMed1975

The role of perceptual cues in the trapezoid oscillatory illusion.

The present experiment was designed to test the hypothesis that binocular disparity functions as a veridical cue, and linear perspective as a nonveridical cue in the perception of a rotating trapezoid. Three trapezoids with proportionately increasing slope were viewed by 10 subjects through viewing screens designed to control the availability of binocular disparity. Monocular and binocular viewing conditions were employed. The dependent variable, proportion of perceived oscillation, was analyzed by a factorial analysis of variance and appropriate post hoc tests. The obtained data indicate that increasing the availability of binocular disparity by increasing viewing screen width favors veridical rotation perception. When the binocular depth cue was attenuated by decreasing viewing screen width, the observer relied on linear perspective, and non-veridical oscillation perception was favored. As linear perspective was increased by increasing trapezoid slope, perceived oscillation increased both monocularly and binocularly. However, for any level of linear perspective, monocular viewing invariabily produced more oscillation than binocular viewing, indicating that monocular depth cues (movement parallax and interposition) were not as effective at neutralizing the illusory perspective effect as the binocular disparity cue.

Adolescent↗
PubMed1981

The role of visual and haptic cues in children's discrimination learning.

Three experiments using kindergarten boys and girls (Ns = 126, 84, and 72, respectively) tested the hypothesis that adding haptic to visual information facilitates discrimination of three-dimensional objects on more difficult (three-choice) problems, but not on easier (two-choice) problems. Kindergartners were given a two-or three-choice discrimination problem under one of four conditions of cue availability: visual cues, haptic cues, and visual plus haptic cues with stimuli touched or not touched before choosing. Addition of haptic cues did not improve performance either on two-choice problems (two or three experiments), as predicted, or on three-choice problems (all three experiments), contrary to predictions.

Child, Preschool↗
PubMed1995

Effect of lateralized kinetic visual cues on visual search in patients with unilateral spatial neglect.

Patients with left neglect following right cerebral infarcts and normal control subjects searched for a single target letter among distractor letters presented on a display screen while kinetic visual cues were continuously presented on the left side or the center of the display screen. Kinetic visual cues presented on the left side enhanced patients' detection of left-sided targets but did not reduce the time that they required to search for left-sided targets. In contrast, the same cues did not alter the patients' detection or rate of search for left-sided targets when they were presented in the center of the display screen. Analysis of these and previous results suggest that kinetic visual cues may be more suitable than other forms of cueing for rehabilitation of neglect and may be particularly effective with neglect patients whose attention is strongly biased to the unneglected side.

Aged↗
PubMed2002

Attentional cueing effect in the identification of words and pseudowords of different length.

Three experiments studied the influence of spatial attention on familiar and unfamiliar letter string identification. Siéroff and Posner's (1988) cueing procedure was used: A cue indicated in advance either the beginning (left) or the end (right) of a foveally presented letter string that participants were instructed to read aloud. Results showed that the precue had a stronger influence on pseudoword than on word identification. Similar results were obtained when participants were instructed to report the identity of the cue or not. For pseudowords, a cueing effect was obtained regardless of length (6, 8, and 10 letters), whereas only 10-letter words showed such an effect, though to a lesser degree than pseudowords of the same length. However, results showed that shorter words were also influenced by the cue location when the exposure duration was reduced. Results are compatible with an early role of spatial attention in letter string processing, but they also suggest that the lexical status of a letter string can directly influence the distribution of attention before the identification process is completely achieved. Although orienting of spatial attention seems heavily involved in a pseudoword identification, some spatial attention mechanism could also take place in the case of familiar words. The results are discussed within two theoretical frameworks concerning the involvement of spatial attention in word identification: The "replacement" theory and the "redistribution" theory.

Adolescent↗
PubMed2005

Calendar and reverse calendar effects: time peaks in memory as a function of temporal cues.

Prior research on autobiographical memory revealed that students typically report more memories from semester boundaries than from other times. Explanations for these calendar effects were examined in two experiments. In Experiment 1, temporal cues were eliminated from the memory cueing task, and an opposite outcome obtained: a greater amount of memories per week in the middle of semesters than at the boundaries (a reverse calendar effect). Experiment 2 replicated and extended this finding by including conditions with temporal cues at different points in the instructions: pre-retrieval or post-retrieval. In the no-cue condition, the reverse calendar effect was replicated. The calendar effect was evident in both cue conditions, but to a greater degree in the pre-retrieval group. These findings contradict encoding explanations of the calendar effect and are best explained by a combination of anchoring bias and temporal landmarks.

Adult↗
PubMed2005

Instructed smoking expectancy modulates cue-elicited neural activity: a preliminary study.

In recent years, research applying functional neuroimaging to the study of cue-elicited drug craving has emerged. This research has begun to identify a distributed system of brain activity during drug craving. A review of this literature suggested that expectations regarding the opportunity to use a drug affected the pattern of neural responses elicited by drug cues. Using functional magnetic resonance imaging (fMRI), we examined the effects of smoking expectancy on the neural response to neutral (e.g., roll of tape) and smoking-related (a cigarette) stimuli in male cigarette smokers deprived of nicotine for 8 hr. As predicted, several brain regions (e.g., the anterior cingulate cortex) exhibited differential activation during cigarette versus neutral cue exposure. Moreover, we found that subregions of the prefrontal cortex (i.e., ventromedial, ventrolateral, and dorsolateral prefrontal cortices) showed cue-elicited activation that was modulated by smoking expectancy. These results highlight the importance of perceived drug use opportunity in the neurobiological response to drug cues.

Adult↗
PubMed2006

A psychometric evaluation of cigarette stimuli used in a cue reactivity study.

Laboratory studies have demonstrated that cigarette smokers react with significant subjective and autonomic responses (e.g., increased craving and increased heart rate) in the presence of stimuli associated with smoking. Although cue reactivity effects are typically robust, a number of methodological considerations make interpretation and design of cue reactivity studies problematic. Previous research has paid scant attention to the psychometric properties of the cigarette cues presented, and standard cues would enhance comparison and synthesis of studies. In the present study, we evaluated 12 cigarette photos (compared with positive, negative, and neutral photos), used in a separate study, for their ability to evoke self-report of craving in both nicotine-deprived and nondeprived smokers. These photos performed as expected, with cigarette pictures evoking significantly higher craving than neutral pictures and deprived smokers showing a trend toward higher craving than nondeprived smokers. The cigarette picture set was evaluated for internal consistency (Cronbach's alpha = .97) as a 12-item scale and further reduced to multiple 2-item scales with reliability estimates ranging from .70 to .93. A cluster analysis of all pictures showed that, when rated for craving, cigarette pictures clustered together, indicating they had distinct properties compared with positive, negative, and neutral pictures. Effect sizes were calculated for each cigarette picture in both deprived and nondeprived smokers. The craving effect sizes ranged from .57 to .98 for nondeprived smokers, and from .61 to .99 for deprived smokers. The analyses suggest these cigarette pictures have excellent psychometric properties for use in future cue reactivity studies.

Adult↗
PubMed1990

Contextual cueing effects in the remote memory of alcoholic Korsakoff patients and normal subjects.

This study examines the effects of contextual cueing on the remote memory of alcoholic Korsakoff patients and normal subjects. Naming of personalities who became famous in each of the five decades beginning 1935 was tested under two conditions: "no-context", in which minimal extraneous cues to identification were provided, and "context", where clear extraneous cues were available. Normal subjects performed better than Korsakoff patients, showed no evidence of a temporal gradient, and exhibited a contextual cueing advantage across all decades. In contrast, Korsakoff patients demonstrated a marked temporal gradient, and the contextual cueing advantage declined systematically as more recent decades were sampled. Further analyses demonstrated that the differential pattern of deficits shown by Korsakoffs and controls was not attributable to absolute differences in performance level. Theoretical implications of these data for explanations of Korsakoff retrograde amnesia are discussed.

Alcohol Amnestic Disorder↗
PubMed2005

Craving and cognitive biases for alcohol cues in social drinkers.

AIMS: To assess whether cognitive biases for drug-related cues are associated with subjective craving and behavioural indices of drug-seeking behaviour, as predicted by incentive models of addiction. METHODS: Fifty social drinkers took part in a laboratory study in which their subjective craving and cognitive biases for alcohol cues were assessed, before they completed a progressive ratio operant task for alcohol (beer) reinforcement. RESULTS: Social drinkers with high levels of alcohol craving at the beginning of the experiment had more pronounced attentional, approach, and evaluative biases for alcohol cues, compared with those with low craving. There were also trends for the high craving group to show greater operant responding for beer reinforcement, but the latter findings were inconclusive, and no evidence was found of associations between the operant responding and cognitive bias measures. CONCLUSIONS: The finding of a relationship between subjective craving and cognitive biases for alcohol cues is consistent with incentive models of addiction. Methodological factors may have obscured the predicted relationships between cognitive bias and operant performance, such as the use of a specific reinforcer (beer) during the operant task, while a range of alcohol-related cues were used in the cognitive bias tasks.

Adolescent↗
PubMed1995

Movement-related potentials in Parkinson's disease. Presence and predictability of temporal and spatial cues.

Activity of the supplementary motor area may be inferred from movement-related potentials (MRPs) which are associated with the preparation and execution of voluntary, or internally determined movements. Supplementary motor area activity may be abnormal in Parkinson's disease since its major input from the basal ganglia is disrupted. Investigation of the abnormalities in supplementary motor area activity associated with movement deficits in Parkinson's disease may therefore reveal functions of the basal ganglia and the supplementary motor area. Movement-related potentials associated with sequential movements were investigated under various cueing conditions in Parkinson's disease subjects and age-matched controls. In controls, MRPs revealed involvement of the supplementary motor area in movements which can be internally determined (non-cued and externally cued, predictable movements, but not unpredictable movements). In Parkinson's disease, however, the supplementary motor area was only involved in movements which must be internally determined (non-cued movements, but not externally cued movements); therefore impaired internal control mechanisms, operating via the supplementary motor area, are bypassed when external cues are given. As a result, Parkinson's disease patients are more reliant on external cues and are unable to use predictive models to internally guide movement. Supplementary motor area involvement also relied on the predictability (in controls) or presence (in Parkinson's disease) of timing cues and not spatial cues, indicating a role of the supplementary motor area and basal ganglia in the temporal organizations of sequential movement rather than the programming of specific movements. For non-cued movements, abnormalities in MRPs for Parkinson's disease subjects consisted of delayed MRP onset and peak times, and prolonged cortical activity following movement. These observations led to a proposed model of the interaction between the basal ganglia and the supplementary motor area, involving the temporal organization of voluntary and internally determined sequential movements.

Aged↗
PubMed1995

Asymmetries in the covert orienting of visual spatial attention to spatial and non-spatial cues in Alzheimer's disease.

The ability to direct covert visual spatial attention to the left (LVF) and right visual field (RVF) was examined in 15 patients with mild to moderate Alzheimer's disease and 15 age- and education-matched controls using the covert orienting of visual spatial attention task (COVAT) modified to include both spatial and non-spatial cues. Subjects responded with a button press when they detected a target at a location 8 degrees to either the left or right of fixation. On 70% of trials a spatial cue was flashed at the target location before the target appeared. On 15% of trials the spatial cue was flashed at the location contralateral to where it would appear and on the remaining 15% of trials non-spatial diffuse cue preceded targets. The cue to target interval (CTI) varied between 150 and 550 ms. Mean reaction times for each cuetype in the RVF and LVF were calculated. Compared with controls, the percentage of trials excluded because of very slow reaction times was significantly greater in the Alzheimer's disease group for the 550 ms CTI. Analysis of the symmetry of reaction times to LVF and RVF targets for the 150 ms CTI enabled us to classify Alzheimer's disease subjects into three subgroups based on the hemifield of abnormally slow attentional biases. The first subgroup showed a significant slowing of reaction time to all LVF targets, the second showed a significant slowing of reaction time to all RVF targets and the third showed a significant slowing of reaction time to both LVF and RVF targets. Patients with Alzheimer's disease who showed an abnormal attentional bias performed significantly better on neuropsychological tests of memory, language and executive function than Alzheimer's disease patients with no attentional bias. Eight of the Alzheimer's disease subjects were assessed serially on at least six occasions over a 12-month period. The initial classification of abnormal attentional bias or no attentional bias was reliable for seven Alzheimer's disease subjects. One Alzheimer's disease subject, initially classified as having a slowed rightward attentional bias, in subsequent testing over the 12-month period was more consistent with symmetrical COVAT performance. Control subjects showed no attentional biases over the 12-month period and the magnitude of asymmetric attentional slowing over the 12-month period was significantly more variable in individual Alzheimer's disease subjects than in controls. The presence of subgroups of patients with Alzheimer's disease with qualitatively different COVAT performance indicates a large between-subject variability in attentional deficits in Alzheimer's disease. The presence of asymmetric attentional slowing and milder neuropsychological deficits in a subgroup of patients with Alzheimer's disease suggests that in these patients there is functional impairment of attentional areas in only one hemisphere rather than an asymmetric impairment of both hemispheres and that the neurodegenerative disease process may have been less advanced or in an earlier stage than that present in Alzheimer's disease patients with symmetric attentional performance and bilateral COVAT impairment. The preservation of asymmetric attentional slowing over time, together with the increased intra-subject variability in the magnitude of these asymmetries, suggests that asymmetrical COVAT performance represents a reliable reflection of underlying hemispheric function in Alzheimer's disease, although designation of asymmetrical attentional biases should be made on the basis of two or more sequential testing sessions.

Aged↗
PubMed2005

Boundary cue invariance in cortical orientation maps.

We effortlessly perceive oriented boundaries defined by either luminance changes ('first-order' cues) or texture variations ('second-order' cues). Many neurons in mammalian visual cortex show orientation preference to both types of boundaries, but it is uncertain how they contribute to perceptual orientation cue-invariance at the neuronal population level. Using optical imaging in cat A 18, we observed highly similar orientation preference maps to first-order and a variety of second-order visual stimuli. Thus the neuronal representation of coarse-scale boundary orientation appears to be invariant to the characteristics (including local orientation) of the fine-scale textures by which those boundaries are defined. A common feature of second-order visual stimuli is that modulation shifts their Fourier energy for boundary orientation to the higher spatial frequencies of their constituent textures - our results suggest a common neural mechanism (demodulation) mediating visual processing of many kinds of texture boundary. The similarity between orientation maps to different stimuli implies that second-order responsive neurons are homogeneously distributed across the cortical surface. Such homogeneously cue-invariant orientation representation could provide a neural substrate for perceptual form-cue invariance, and reflect an optimal organization for encoding orientation information in natural scenes.

Animals↗
PubMed2002

Effect of cocaine and sucrose withdrawal period on extinction behavior, cue-induced reinstatement, and protein levels of the dopamine transporter and tyrosine hydroxylase in limbic and cortical areas in rats.

Lever pressing during tests for resistance to extinction and cue-induced reinstatement of cocaine seeking in rats progressively increases over the first 2 months of withdrawal. In the present report, we investigated the generality of these findings in rats trained to self-administer sucrose, a non-drug reinforcer. We also examined whether the time-dependent changes in cocaine seeking correlate with the levels of the dopamine transporter (DAT) and tyrosine hydroxylase (TH) proteins in the amygdala, nucleus accumbens, prefrontal cortex and orbitofrontal cortex. Rats were trained to self-administer cocaine (0.5 mg/kg/i.v. infusion) or 10% sucrose (0.2 ml/infusion into a liquid drop receptacle) for 10 days (6 h/day); each reward delivery was paired with a tone+light cue. Tests for cocaine seeking were conducted following 1 or 15 reward-free days. On the test day, rats were initially tested for resistance to extinction during 6-7 60-min extinction sessions in the absence of the tone-light cue, until they reached the extinction criterion of less than 15 responses/60 min. Subsequently, rats were tested for cue-induced reinstatement during a 60-min session in which each lever press led to a contingent presentation of the tone-light cue. Lever pressing during the tests for reward seeking was significantly greater on day 15 than on day 1 following withdrawal from both cocaine and sucrose self-administration training. The levels of DAT, but not TH, were greater in the prefrontal cortex of cocaine-trained rats than in sucrose-trained rats on both days 1 and 15 of withdrawal. The levels of DAT and TH in other brain areas were not altered following withdrawal from cocaine or sucrose self-administration. These data suggest that the withdrawal can modulate reward seeking of both drug and non-drug reinforcers, and that alterations in DAT and TH levels in the brain regions examined do not mediate this effect.

Animals↗
PubMed2003

Chronic ethanol consumption by C57BL/6 mice promotes tolerance to its interoceptive cues and increases extracellular dopamine, an effect blocked by naltrexone.

BACKGROUND: C57BL/6 (B6) mice voluntarily consume ethanol. Although preingestive factors might be accountable, the fact that B6 mice voluntarily consume sufficient ethanol to set the conditions for an ethanol-deprivation effect suggest that post-ingestive pharmacological induced changes also occur. In this study, we determined the amounts of ethanol voluntarily consumed by B6 mice and associated blood ethanol levels (BEL), the effects of this consumption on extracellular dopamine (DA) and how this was altered by naltrexone, as well as on its interoceptive discriminative cues. METHODS: In experiment 1, the amounts of 12% ethanol consumed at 2, 4, and 6 hr into the active phase of the circadian cycle and associated BEL were determined. In experiment 2, dialysate samples were collected for 1 hr to establish basal DA levels. Mice were then injected with saline or naltrexone (6 mg/kg) and given access to water and 12% ethanol or to water only, and samples were collected at 20-min intervals for the next 2 hr. In experiment 3, mice were trained to discriminate ethanol's interoceptive cues via operant techniques, and half were given 3 weeks access to ethanol and water, the other half water only. Ethanol-consuming and water control mice were again tested for their ability to discriminate the drug's interoceptive cues. RESULTS: Mice ingested nearly 6 g/kg of ethanol and attained BEL near 100 mg/100 mL by 6 hr into the active phase. Ethanol intake at 2-hr into the dark phase was approximately 2.5 g/kg, and increased DA to approximately 100% above basal levels. Naltrexone reduced ethanol consumption and blocked the DA increase. Ethanol consumption for 3 weeks attenuated its discriminative cues. CONCLUSIONS: B6 mice voluntarily consume sufficient ethanol (1) to produce intoxicating BEL; (2) to increase DA levels in nucleus accumbens, an effect blocked by naltrexone; and (3) to attenuate its discriminative cues.

Alcoholism↗
PubMed2004

Nurses' beliefs and values about doing cue-based care in an NICU in Taiwan.

Although advances in medical technology have increased the survival rate of preterm infants, science is no cure-all for these high-risk patients. A growing number of studies report that caregiving interventions cause physiological and behavioral distress in such infants. The results have prompted changes in caregiving practices, attempting to reduce stress and strengthen protection for the infants, in order to promote their stability and development in the neonatal intensive care unit (NICU) . This study uses qualitative research methods to grasp the richness and diversity of nurses' beliefs and experience in the taking care of preterm infants. Ten groups of questions explore how NICU nurses take care of premature infants, nurses' perspectives on cue-based care, and the extent to which NICU nurses practice cue-based care. The results generated three themes: (1) timely and skillful management of the preterm infants; (2) compassionate and holistic care for the infants and their highly stressed families; and (3) the relationship between good nursing care and meeting the needs of preterm infants, families, physicians, units, and the environment. It is apparent that the approach to care delivery in NICU practice is still clinical-based, and that there are some obstacles to the delivery of cue-based care. The reasons for this include lack of knowledge, incomplete collaboration with team members, and insufficient support from the administrative systems. To improve the quality of nursing care and preterm infant outcomes, it will be necessary to educate NICU nurses on cue-based care, to enhance collaboration among all team members, to reduce their non-nursing workload, and to re-design NICUs for optimal cue-based care.

Adult↗