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PubMed2001

Attentional requirements is visual detection and identification: evidence from the attentional blink.

Perception of the 2nd of 2 targets (T1 and T2) is impaired if the lag between them is short (0-500 ms). The authors used this attentional blink (AB) to index attentional requirements in detection and identification tasks, with or without backward masking of T2, in 2 stimulus domains (line orientation, coherent motion). With masking, the AB occurred because T2 was masked during the attentional dwell time created by T1 processing (Experiments 1, 2, and 3). Without masking, an AB occurred only in identification because during the attentional dwell time, T2 decayed to a level that could support simple detection but not complex identification. However, an AB occurred also in detection if T2 was sufficiently degraded (Experiment 4). The authors drew 2 major conclusions: (a) Attention is required in both identification and detection, and (b) 2 factors contribute to the AB, masking of T2 while attention is focused on T1 and decay of the T2 trace while unattended.

Attention↗
PubMed1999

Quantitative modeling of visual attention processes in patients with Parkinson's disease: effects of stimulus integrality on selective attention and dimensional integration.

Parkinson's disease (PD) patients and normal controls (NCs) were administered a series of visual attention tasks. The dimensional integration task required integration of information from 2 stimulus dimensions. The selective attention task required selective attention to 1 stimulus dimension while ignoring the other stimulus dimension. Both integral- and separable-dimension stimuli were examined. A series of quantitative models of attentional processing was applied to each participant's data. The results suggest that (a) PD patients were not impaired in integrating information from 2 stimulus dimensions, (b) PD patients were impaired in selective attention, (c) selective attention deficits in PD patients were not due to perceptual interference, and (d) PD patients were affected by manipulations of stimulus integrality and separability in much the same way as were NCs.

Aged↗
PubMed2005

Mood-congruent attentional bias in dysphoria: maintained attention to and impaired disengagement from negative information.

Attentional bias to negative information has been proposed to be a cognitive vulnerability factor for the development of depression. In 2 experiments, the authors examined mood-congruent attentional bias in dysphoria. In both experiments, dysphoric and nondysphoric participants performed an attentional task with negative, positive, and neutral word cues preceding a target. Targets appeared either at the same or at the opposite location of the cue. Overall, results indicate that dysphoric participants show maintained attention for negative words at longer stimulus presentations, which is probably caused by impaired attentional disengagement from negative words. Furthermore, nondysphoric participants maintain their attention more strongly to positive words. These results are discussed in relation to recent developments in the pathogenesis and treatment of depression.

Adult↗
PubMed1994

Attentive novelty detection in humans is governed by pre-attentive sensory memory.

Being able to detect unusual, possibly dangerous events in the environment is a fundamental ability that helps ensure the survival of biological organisms. Novelty detection requires a memory system that models (builds neural representations of) events in the environment, so that changes are detected because they violate the predictions of the model. The earliest physiologically measurable brain response to novel auditory stimuli is the mismatch negativity, MMN, a component of the event-related potential. It is elicited when a predictable series of unvarying stimuli is unexpectedly followed by a deviating stimulus. As the occurrence of MMN is not usually affected by the direction of attention, MMN reflects the operation of automatic sensory (echoic) memory, the earliest memory system that builds traces of the acoustic environment against which new stimuli can be compared. The dependence of attentive novelty detection on earlier, pre-attentive processes, however, has remained elusive. Previous, related studies seem to suggest a relationship between MMN and attentive processes, although no conclusive evidence has so far been shown. Here we address novelty detection in humans both on a physiological and behavioural level, and show how attentive novelty detection is governed by a pre-attentive sensory memory mechanism.

Acoustic Stimulation↗
PubMed1998

Vision and attention. II: Is visual attention a mechanism through which a deficient magnocellular pathway might cause reading disability?

Recent research in reading disability has discovered that at least some reading-disabled subjects have deficits in their magnocellular (M) visual pathways. However, the mechanism by which M pathway deficits affect reading has not been addressed. Abnormal attention has long been known to be associated with reading-disabled individuals, and new research in visual attention has determined that transient visual attention is dominated by M-stream inputs. The purpose of this study was to determine whether visual attention might be the mechanism through which a faulty M pathway could produce visual deficits in reading-disabled subjects. Spatiotemporal attentional response functions were measured using the Line Motion Illusion and compared in normal and disabled readers. Specific abnormalities in the visual attention mechanisms of disabled readers were found which might suggest mechanisms by which reading could be affected by a deficient M stream.

Adult↗
PubMed2003

Single-trial classification of parallel pre-attentive and serial attentive processes using functional magnetic resonance imaging.

Theories of perception have proposed a basic distinction between parallel pre-attentive and serial attentive modes of processing. However, chronometric measures are often ambiguous in separating parallel and serial processes. We have used the activity of attention-related regions of the human brain, measured with functional magnetic resonance imaging, to separate parallel from serial processes at the single-trial level in a visual quantification task. In this task, some have suggested the deployment of two qualitatively different processes, a fast parallel 'subitizing' for sets of one, two or three objects and a slow serial counting for larger sets. Our results indicate that attention-related regions of the posterior parietal and frontal cortices show a sudden increase in activity only from numerosity four onwards, confirming the parallel-serial dichotomy of subitizing and counting. Moreover, using the presence or absence of attentional shifts, as inferred from the activation of posterior parietal regions, we successfully predict whether, on a given trial, subjects deployed a serial exploration of the display or a parallel apprehension. Beyond the subitizing/counting debate, this approach may prove useful to probe the attentional demands of other cognitive tasks.

Adult↗
PubMed1999

Spatial attention and neglect: parietal, frontal and cingulate contributions to the mental representation and attentional targeting of salient extrapersonal events.

The syndrome of contralesional neglect reflects a lateralized disruption of spatial attention. In the human, the left hemisphere shifts attention predominantly in the contralateral hemispace and in a contraversive direction whereas the right hemisphere distributes attention more evenly, in both hemispaces and both directions. As a consequence of this asymmetry, severe contralesional neglect occurs almost exclusively after right hemisphere lesions. Patients with left neglect experience a loss of salience in the mental representation and conscious perception of the left side and display a reluctance to direct orientating and exploratory behaviours to the left. Neglect is distributed according to egocentric, allocentric, world-centred, and object-centred frames of reference. Neglected events can continue to exert an implicit influence on behaviour, indicating that the attentional filtering occurs at the level of an internalized representation rather than at the level of peripheral sensory input. The unilateral neglect syndrome is caused by a dysfunction of a large-scale neurocognitive network, the cortical epicentres of which are located in posterior parietal cortex, the frontal eye fields, and the cingulate gyrus. This network coordinates all aspects of spatial attention, regardless of the modality of input or output. It helps to compile a mental representation of extrapersonal events in terms of their motivational salience, and to generate 'kinetic strategies' so that the attentional focus can shift from one target to another.

Attention↗
PubMed2002

Visual attention to color: parvocellular guidance of attentional resources?

Although transient changes in luminance have been well documented to automatically attract attention to their location, experiments looking at abrupt changes in color have failed to find similar attentional capture. These results are consistent with current theories of the role of the magnocellular (M) and parvocellular (P) streams that postulate that the M stream, which is "color-blind," plays the dominant role in guiding attention and eye movements. The experiment reported here used stimuli that contained only information defined by color, and masked residual luminance information with dynamic noise, to assess the capacity of purely chromatic cues to automatically guide spatial attention. Such stimuli were as effective as those containing large luminance signals in guiding attention. To the extent that these purely chromatic signals isolated the P stream, these results suggest that this stream is also capable of automatic attentional capture. Hence, color vision not only aids target identification but also is a strong aid for target detection and localization.

Adult↗
PubMed2006

An event-related potential study of supramodal attentional control and crossmodal attention effects.

We conducted two audiovisual experiments to determine whether event-related potential (ERP) components elicited by attention-directing cues reflect supramodal attentional control. Symbolic visual cues were used to direct attention prior to auditory targets in Experiment 1, and symbolic auditory cues were used to direct attention prior to visual targets in Experiment 2. Different patterns of cue ERPs were found in the two experiments. A frontal negativity called the ADAN was absent in Experiment 2, which indicates that this component does not reflect supramodal attentional control. A posterior positivity called the LDAP was observed in both experiments but was focused more posteriorly over the occipital scalp in Experiment 2. This component appears to reflect multiple processes, including visual processes involved in location marking and target preparation as well as supramodal processes involved in attentional control.

Acoustic Stimulation↗
PubMed1992

Attention and para-attentional processing. Event-related brain potentials as tests of a model.

In 1972 when we began to analyze the vast amount of material from the laboratories of physiological psychologists, we had only a vague conceptualization of what a model of attention might look like. We began where everyone else had, with the view that everything had something to do with "arousal" but with Lacey's (1967) warning in mind that all of the dependent variables might not actually be measuring aspects of the same process. With this warning in mind, we were forced by the data to organize them into a three-systems mode. Since the first publication of this model in 1975, we have found increasing amounts of evidence to support and extend it. This evidence is briefly reviewed in the present paper in terms of the techniques employed in various types of investigation. Further, the current review of data has made it possible to specify the para-attentional substrate (the extrinsic lemniscal primary projection systems) upon which the three systems described in the earlier model operate. The earlier model was based on psychophysiological, neurobehavioral and neurochemical analyses while the current specification results from the results of recordings of event-related brain electrical responses. The conclusions derived from these results can be summarized as follows: First. It has become possible to distinguish controlled attention from the para-attentional pre- and post-attentive automatic processes upon which controls operate. Second. The pre- and post-attentive processes appear to be coordinate with activity in the extrinsic lemniscal primary sensory projection systems. Processing in these systems is reflected in the early components of event-related brain electrical potentials. These extrinsic systems are, however, not just throughputs for further processing. Rather, they are sensitive to the history of reinforcement which the subject has experienced. The concept of a limited channel capacity must, therefore, be modified to encompass this ability of organisms to improve, through practice, their competence to process a great deal of information in parallel. Competence, not capacity, limits central processing span. Third. A set of intrinsic extralemniscal processing systems has been identified to operate via a tecto-tegmental pathway to the reticular nucleus of the thalamus. The later components (N2P3, etc.) of event-related potentials have been shown to reflect processing in these systems and those that control them. Activity in these systems has been related to targeted conscious awareness.(ABSTRACT TRUNCATED AT 400 WORDS)

Amygdala↗
PubMed1998

The effects of attentional spread and attentional effort on orientation discrimination.

The spatial properties of visual attention and its relation to attentional effort have been investigated, and it has been found that stimulus detectability changes as a function of attentional beam width and degree of task difficulty. Using a matching-to-sample paradigm, two Gabor patches were presented simultaneously both as a sample stimulus and a test stimulus, the stimuli set at three different distances. Task difficulty was gradated by changing the orientation difference of the two Gabor patches on nonmatching trials. 'Difficult' nonmatching probe trials were embedded within an easy block of trials (easy condition), and vice versa for 'easy' probe trials. The detectability, d', differences of probe trials in the two conditions were calculated as a measure of change in attention. Our results show that the detectability of a pair of stimuli decreases with an increase in the distance between stimuli. Furthermore, the results indicate an increase in attentional effort for various attentional beam widths and that r = d'easy/d'difficult of the probe trials is constant throughout the different stimuli separation.

Attention↗
PubMed1997

Noncontingent presentation of attention and alternative stimuli in the treatment of attention-maintained destructive behavior.

Previous research has demonstrated that destructive behavior may be reduced through noncontingent presentation of attention when attention is identified as the stimulus responsible for behavioral maintenance. Because it may not always be possible to deliver attention in all situations, we examined the extent to which alternative stimuli that have been identified through a choice assessment would substitute for attention (the functional analysis-based reinforcer) in a noncontingent reinforcement procedure. Prior to treatment, functional analyses demonstrated that the destructive behavior of 2 clients with mental retardation was maintained by adult attention. Next, a stimulus choice assessment identified highly preferred tangible items for the 2 clients. Finally, we compared the effectiveness of two noncontingent reinforcement procedures: continuous noncontingent access to attention and continuous noncontingent access to the tangible item identified in the choice assessment. For both clients, these noncontingent reinforcement procedures reduced destructive behavior. The results are discussed in terms of the clinical implications for the treatment of destructive behavior using functional and alternative stimuli.

Attention↗
PubMed1999

Effects of presession attention on the frequency of attention-maintained behavior.

The effect of prior attention was systematically manipulated to study its influence on rates of yelling and head hitting, both maintained by positive reinforcement in the form of attention. Higher levels of head hitting occurred in analogue attention conditions when the person was deprived of attention (no social interactions for 1 hr) prior to the analysis in comparison to when the person received high levels of attention (attention delivered on a fixed-time 30-s schedule for 1 hr) prior to the analysis.

Adult↗
PubMed2000

The effects of presession exposure to attention on the results of assessments of attention as a reinforcer.

The effects of presession exposure to attention on responding during subsequent assessments of attention as a reinforcer were evaluated across three behavioral assessments. In Experiment 1, a contingent attention assessment condition was preceded by either a noncontingent attention condition (free play) or a contingent escape condition. In Experiment 2, a diverted attention with extinction condition was preceded by either an alone or a free-play condition. In Experiment 3, a two-choice preference assessment was preceded by either 10 min of free play or 10 min of playing alone. In each experiment, the participant responded differentially within the test condition according to the presence or absence of dense schedules of attention immediately prior to that condition. The results of this study show that events occurring immediately prior to an assessment condition can influence behavior within the assessment.

Attention↗
PubMed2006

Exploring the role of attention during memory retrieval: effects of semantic encoding and divided attention.

Research on attention and memory suggests that semantic encoding leads to retrieval that is highly susceptible to divided attention. Three experiments tested this proposition and showed that dividing attention did not selectively affect semantically encoded items. Participants encoded a list of words in one of two ways: semantically or phonetically. Later, memory was assessed using either a standard recognition test (Experiment 1) or a rhyme recognition test (Experiments 2 and 3). The participants took the memory test either alone (full attention) or while simultaneously performing a secondary task (divided attention). Recognition accuracy was reduced by divided attention on both recognition tests, and semantically and phonetically encoded words were equally affected.

Attention↗
PubMed2001

Contingent attentional capture or delayed allocation of attention?

Under certain circumstances, external stimuli will elicit an involuntary shift of spatial attention, referred to as attentional capture. According to the contingent involuntary orienting account (Folk, Remington, & Johnston, 1992), capture is conditioned by top-down factors that set attention to respond involuntarily to stimulus properties relevant to one's behavioral goals. Evidence for this comes from spatial cuing studies showing that a spatial cuing effect is observed only when cues have goal-relevant properties. Here, we examine alternative, decision-level explanations of the spatial cuing effect that attribute evidence of capture to postpresentation delays in the voluntary allocation of attention, rather than to on-line involuntary shifts in direct response to the cue. In three spatial cuing experiments, delayed-allocation accounts were tested by examining whether items at the cued location were preferentially processed. The experiments provide evidence that costs and benefits in spatial cuing experiments do reflect the on-line capture of attention. The implications of these results for models of attentional control are discussed.

Adolescent↗
PubMed2005

Attention control and ability level in a complex cognitive skill: attention shifting and second-language proficiency.

In this study, we investigated the relationship between attention control and proficiency in a complex cognitive skill. The participants were English-French bilinguals with varying degrees of second-language (French) proficiency. Proficiency was operationalized as efficiency of lexical access in an animacy judgment task, as reflected in the coefficient of variability of response time adjusted for first-language performance on the same task. Attention control was operationalized as the shift cost obtained in a linguistic version of the alternating runs task-switching paradigm. Hierarchical regression revealed that, overall, attention control accounted for 59% of the variance of proficiency and that second-language attention control alone accounted for 32% of the unique variance of proficiency, indicating a high degree of skill domain (second language) specificity in the relationship between attention control and proficiency. The results speak to issues regarding the development of expertise, second-language acquisition, and a cognitive linguistic approach to language and attention.

Adult↗
PubMedDate not supplied

[Attention and executive function tests components in attention deficit/hyperactivity children].

INTRODUCTION: It has been suggested that children with attention deficit/hyperactivity disorder (ADHD) have problems in attention and executive functions. A factor analysis showed that ADHD children had a different factor structure of the executive functions when they were compared with controls. AIM. To determine the factor structure of attention and executive functions in a group of ADHD children compared with a group of controls. SUBJECTS AND METHODS: 249 ADHD children and 372 controls of both genders, aged 6 to 11 years old, and from the different socio economic strata of Medellín city, were selected. Attention --Mental Control and Auditory Continuous Performance Test (ACPT)-- and executive functions --Phonologic and Semantic Verbal Fluency (FAS)--, and a shortened version of the Wisconsin Card Sorting Test (WCST) were assessed in both groups. Factor analyses were developed with principal components procedure were developed for each group and the total sample, using principal component procedure with orthogonal rotation. RESULTS: Stable factor structures were found for each group and for the total sample. The general factor structure was constituted by three independent factors: 1- Categorization, 2- Verbal fluency and verbal sustained attention, and 3- Cognitive flexibility. This factor structure explained 74.9% of the variance. CONCLUSION: The factor structures suggested that the components of attention and executive functions are similar for ADHD and control groups. The differences between groups would be quantitative.

Attention Deficit Disorder with Hyperactivity↗