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PubMed1986

Hemispheric specialization and attention: effects of complete and partial callosal section and hemispherectomy on dichotic monitoring.

Dichotic word monitoring tasks were given to four cases with complete forebrain comissurotomy, three cases of partial section of the corpus callosum, one case of right hemispherectomy, and control subjects. The task involved a unimanual response to target words in either ear (divided attention, Experiment 1) or to target words in one voice that changed ears unpredictably (focused attention, Experiment 2). Left-ear extinction, defined as chance level (25%) detection of left-ear targets and 75% right-ear target detection, varied both between and within subjects during divided attention. No examples of extinction were obtained with focused attention. These results highlight attentional aspects of dichotic listening. Neither the structural, hemispheric asymmetry model (Cortex 3, 163-178, 1967), nor the cognitive, attention priming model (Attention and Performance V, pp. 87-97, Academic Press, New York) could account for the obtained results. We propose an alternative account in terms of the different processing modes and attentional capabilities of the two cerebral hemispheres.

Adolescent↗
PubMed1993

Time for reorienting of attention: a premotor hypothesis of the underlying mechanism.

The paradigm of the covert orienting of attention (COA) has shown that the displacement of visual attention may be assessed even in the absence of eye movement. Stimuli correctly cued before their presentation are usually detected faster than uncued stimuli. However, miscued stimuli induce an increased detection time, which has been attributed to the time required for the reorientation of attention from the incorrect to the correct spatial location. Currently, the mechanism of such a displacement of visual attention remains unknown. Rizzolatti et al. Neuropsychologia 25, 31-40 (1987) have suggested a premotor hypothesis which suggests that an oculomotor disprogramming and reprogramming is necessary to reorient visual attention, even if the eye movement is inhibited. Since shifting of auditory attention from one ear to the other does not require any motor control, we further investigated the model of COA in 20 normal subjects who performed two tasks requiring a reorienting of auditory attention: (1) a choice RT task that requires a response readjustment during the auditory reorienting; (2) a simple RT task that does not require a response readjustment during the auditory reorienting; (2) a simple RT task that does not require a response readjustment during the auditory reorienting. Results indicate that correctly cued stimuli significantly reduce the RT in both tasks and that this reduction is greater in the choice than in the simple RT task. This suggests that a correct cue may produce a pre-programming of the response, in addition to the pre-engagement of the perceptual attention.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMed1995

Asymmetries in the covert orienting of visual spatial attention in schizophrenia.

The presence of attentional asymmetries in patients with schizophrenia was investigated with particular emphasis on the effects of stage of disease, medication status and clinical symptom severity. A modified version of Posner's covert orienting of visual attention task (COVAT) which included both spatial and non-spatial cues was administered to six volunteer samples of subjects which consisted of (i) 15 unmedicated and acutely psychotic male subjects with schizophrenia, (ii) 15 male subjects with schizophrenia who had been receiving medication for 14-21 days, (iii) 10 chronic male schizophrenic subjects who had been receiving medication for at least two years, (iv) 10 acutely psychotic male subjects with non-schizophrenic psychoses, (v) 15 subjects with unilateral brain frontal lobe (n = 6) or parietal lobe (n = 9) lesions, (vi) and 15 male control subjects. Measures of saccadic and pursuit eye movements were also obtained from unmedicated and recently medicated subjects with schizophrenia. COVAT attentional asymmetries were present in unmedicated subjects with schizophrenia for the 150 msec stimulus onset asynchrony (SOA). These asymmetries arose because reaction times (RTs) to right visual field targets were significantly slower than RTs to left visual field targets when targets followed invalid spatial or non-spatial cues. These asymmetries were qualitatively similar to those found in the patients with unilateral parietal lobe lesions. Attentional asymmetries partially resolved with brief periods of medication and completely resolved with long periods of medication. No asymmetries were found in controls nor in unmedicated subjects without schizophrenia. No asymmetries of ocular motor function were found. In schizophrenia, attentional asymmetries may reflect a deficit in the disengagement of visual attention from the right visual field and appear to be a stage marker for the disease. However this attentional deficit is dynamic and may reflect disruption to the neurocognitive network controlling attention at the level of the anterior cingulate cortex.

Adolescent↗
PubMed1991

Spontaneous selective attention in schizophrenia.

A visual word identification task was used to measure the type of selective attention that occurs spontaneously when there are multiple stimuli, all potentially relevant, and insufficient time to process each of them fully. This task presents two words simultaneously, one above the other, for 200 ms, and periodically requires the subject to identify either the upper or the lower word. We tested schizophrenic patients, manic-depressive patients, and normal controls under a baseline divided attention condition with no predictability and then introduced a degree of predictability into the upper location that normally results in selective attention to the lower nonpredictable location. In both the divided attention and the selective attention conditions, the schizophrenic group was just as accurate in identifying words as the other two groups, indicating no deficit in the rate of information processing. However, spontaneous selective attention under conditions of predictability was abnormal in the schizophrenic patients: They paid more attention to the predictable than to the nonpredictable source of information, consequently processing different, not less, information than normal subjects. Abnormal values on a ratio measure of selective attention occurred in 85% of the schizophrenic patients compared with only 30% of the manic-depressives and 20% of the normal subjects.

Adult↗
PubMed1995

Visual attention in patients with chronic obstructive pulmonary disease.

The selective visual attention of 39 patients with chronic obstructive pulmonary disease (COPD) was measured by the Bourdon-Vos test and compared with the attention performance of 38 healthy controls of the same age range. The correlation between the attention of the COPD patients and day- and night-time parameters was determined. Furthermore, in 44 other COPD patients with daytime hypoxaemia, the effect of one night of oxygen supplementation and of a 7-day treatment with two respiratory stimulants (chlormadinone acetate) (CMA) or acetazolamide (ACET) on attention performance was studied. The results showed that the attention performance of COPD patients was lower than that of controls. Significant correlations were found between the mean line time (attention parameter) and the following parameters: age, inspiratory vital capacity (IVC), hypercapnic ventilatory response (HCVR), daytime arterial oxygen saturation (SaO2), daytime arterial oxygen pressure (PaO2), daytime arterial carbon dioxide pressure (PaCO2), mean nocturnal SaO2, lowest nocturnal SaO2 and the standard deviation of the mean nocturnal SaO2. Multiple linear regression analysis showed that, apart from age, only the nadir of the nocturnal SaO2 contributed to the prediction of the attention. No clinically important short-term effect of oxygen or respiratory stimulating therapy on the attention performance was found.

Acetazolamide↗
PubMed1996

Focussing on aging: an electrophysiological exploration of spatial and attentional processing during reading.

Three types of selective attention tasks were presented to 24 young (20.5 years) and 24 middle-aged (57.5 years) participants. The major aim of the experiment was to explore three different aspects of selective attention, namely a pre-attentive level (i.e. auditory passive oddball task), an attentive level using spatial attention in a memory search task (i.e. selective search task) and an attentive level using a spatial cue to select a word in a reading-like situation (i.e. selective language task). The data showed that the mismatch negativity was not affected by aging although the ERPs indicated that the younger participants were paying more attention to the tones than the middle-aged. The selective search task data showed that spatial selective attention is only mildly affected by aging. The ERP-data seemed to indicate that irrelevant stimuli had a smaller impact in the middle-aged. The selective language data showed a look-a-like effect of flanker words for both age groups although the effect in the middle-aged was delayed by 30 ms and smaller. It was theorized that flankers might have smaller impact in the middle-aged. N400 was found to be smaller and delayed (90 ms) in the middle-aged participants. The overall conclusion on the basis of the three experiments is that the selectivity of processing was preserved or even enhanced in our particular group of middle-aged participants.

Adult↗
PubMed2006

Dissociation of the component processes of attention in healthy adults.

Cohen's [Cohen, R. (1993). The Neuropsychology of Attention. New York: Plenum Publishing] model of attention proposes four interrelated processes, namely Sensory Selective Attention, Response Selection/Control, Focus/Capacity, and Sustained Attention. Though this model has been supported in patient samples, it has not been examined in a healthy adult cohort. Using Principal Components Analysis, we examined the explanatory power of this model in 342 adults screened for significant medical and psychiatric history. The four derived components accounted for 58.7% of the total variance. Results were generally supportive of Cohen's [Cohen, R. (1993). The Neuropsychology of Attention. New York: Plenum Publishing] model, though further clarification of the relationship between processing speed and more complex aspects of attention (e.g. working memory, set shifting) is needed. These findings support the notion that attention is not a unitary process, but instead comprised of distinct components. Future studies including both neuropsychological testing and functional neuroimaging may provide important insight into the underpinnings of attentional processes.

Adolescent↗
PubMed2004

Time estimation: the effect of cortically mediated attention.

Do people tend to underestimate time when their attention is engaged? Studies supporting this idea have routinely confounded attentional manipulations with changes in other factors, such as response complexity and memory load. The aim of the present study was to obtain the first direct evidence that attentional engagement mediated by cortical brain mechanisms affects time estimation. Participants were asked to perform a visual search task that either should not demand attention (simple feature search) or should demand cortical attentional engagement (conjunction search). Observers searched through 2, 4, 8, 16, 24, 32, or 40 items, for blocks of 40 or 60 trials. At the conclusion of each block participants were required to provide a written estimate of block duration. This time estimate was prospective in nature because subjects knew in advance that they would be asked to produce the estimate. Results showed that an attentionally demanding conjunction search task produced a large underestimation of time. And as the engagement of attention increased so did the underestimation of time. These findings provide strong support for an attentional model of prospective time estimation that is subserved by cortical brain mechanisms.

Adolescent↗
PubMed2006

Cognitive Ethology and exploring attention in real-world scenes.

We sought to understand what types of information people use when they infer the attentional states of others. In our study, two groups of participants viewed pictures of social interactions. One group was asked to report where the people in the pictures were directing their attention and how they (the group) knew it. The other group was simply asked to describe the pictures. We recorded participants' eye movements as they completed the different tasks and documented their subjective inferences and descriptions. The findings suggest that important cues for inferring attention of others include direction of eye gaze, head position, body orientation, and situational context. The study illustrates how attention research can benefit from (a) using more complex real-world tasks and stimuli, (b) measuring participants' subjective reports about their experiences and beliefs, and (c) observing and describing situational behavior rather than seeking to uncover some putative basic mechanism(s) of attention. Finally, we discuss how our research points to a new approach for studying human attention. This new approach, which we call Cognitive Ethology, focuses on understanding how attention operates in everyday situations and what people know and believe about attention.

Adult↗
PubMed2006

Neural correlates of within-level and across-level attention to multiple compound stimuli.

Event-related potentials (ERPs) were recorded to investigate the neural mechanisms of attention to the same or different levels of two compound letters presented concurrently in the left and right visual fields, respectively. Relative to the condition when attention was allocated to the global level of one compound stimulus and the local level of another one (across-level attention), attention to the same level of the two compound stimuli (within-level attention) increased an early positivity between 100 and 140 ms (P1) over the occipito-parietal cortex. A long-latency positivity between 320 and 560 ms (P3) over the central-parietal area was also increased in the within-level relative to across-level attention conditions. The ERP results suggest that, relative to across-level attention, within-level attention to multiple compound stimuli facilitates both early sensory-perceptual processing and late process of stimulus evaluation and identification in hierarchical analysis.

Attention↗
PubMed2005

Selective attention event-related potential effects from auditory novel stimuli in children and adults.

OBJECTIVE: We investigated differences between children and adults in selective attention. METHODS: Event-related potentials of 9 year-old children and adults were studied. Subjects performed an active dichotic novelty oddball task. We examined age-related differences in early selection by comparing non-target tones and late selection by comparing target tones in the attended and unattended channels. RESULTS: In children, an attention effect was seen on the N1 response to standard tones. For the targets, both children and adults displayed enhanced P3b amplitudes on the attended side, and in adults, an attention effect was also seen on the N2 response. In children, novelty-elicited N2 responses were larger to left ear stimuli irrespective of the direction of attention. Adults displayed enhanced novelty-elicited N2 amplitudes on the attended side. CONCLUSIONS: Developmental changes occur both in early attentional selection and target detection. Children employed efficiently the mechanisms of early selection when processing standard stimuli, whereas their processes in relation to novel stimuli were attention-independent and even varied with ear. Adults were able to maintain their attentional focus in the presence of unexpected stimuli. SIGNIFICANCE: The results of this study contribute to elucidation of the development of selective attention.

Acoustic Stimulation↗
PubMed2005

Effect of spatial attention on human sensorimotor integration studied by transcranial magnetic stimulation.

OBJECTIVE: Recent transcranial magnetic stimulation (TMS) studies showed that the sensory input can decrease the motor cortex excitability (afferent inhibition). To clarify the effect of attention on sensorimotor integration, we investigated the effect of spatial attention on afferent inhibition. METHODS: Right median nerve electrical stimulation followed, at variable delays (10-300 ms), by TMS over the left motor cortex was applied to 9 subjects, during 3 conditions; spatial attention to the right and left hand, and control (no attention) tasks. RESULTS: Inhibition of the motor evoked potential occurred at inter-stimulus interval of 20 and 100 ms, which was more was marked during spatial attention to the right than to the left hand. CONCLUSIONS: Enhancement of the afferent inhibition induced by spatial attention to the stimulated side is likely to reflect the interaction between attention and sensorimotor integration. SIGNIFICANCE: The spatial attention may modulate the sensorimotor integration studied by afferent inhibition of the MEP.

Adult↗
PubMed2006

The development of involuntary and voluntary attention from childhood to adulthood: a combined behavioral and event-related potential study.

OBJECTIVE: This study investigated auditory involuntary and voluntary attention in children aged 6-8, 10-12 and young adults. The strength of distracting stimuli (20% and 5% pitch changes) and the amount of allocation of attention were varied. METHODS: In an auditory distraction paradigm event-related potentials (ERPs) and behavioral data were measured from subjects either performing a sound duration discrimination task or watching a silent video. RESULTS: Pitch changed sounds caused prolonged reaction times and decreased hit rates in all age groups. Larger distractors (20%) caused stronger distraction in children, but not in adults. The amplitudes of mismatch negativity (MMN), P3a, and reorienting negativity (RON) were modulated by age and by voluntary attention. P3a was additionally affected by distractor strength. Maturational changes were also observed in the amplitudes of P1 (decreasing with age) and N1 (increasing with age). P2-modulation by voluntary attention was opposite in young children and adults. CONCLUSIONS: Results suggest quantitative and qualitative changes in auditory voluntary and involuntary attention and distraction during development. The processing steps involved in distraction (pre-attentive change detection, attention switch, reorienting) are functional in children aged 6-8 but reveal characteristic differences to those of young adults. In general, distractibility as indicated by behavioral and ERP measures decreases from childhood to adulthood. SIGNIFICANCE: Behavioral and ERP markers for different processing stages involved in voluntary and involuntary attention reveal characteristic developmental changes from childhood to young adulthood.

Acoustic Stimulation↗
PubMed2005

Taking control of reflexive social attention.

Attention is shifted reflexively to where other people are looking. It has been argued by a number of investigators that this social attention effect reflects the obligatory bottom-up activation of domain-specific modules within the inferior temporal (IT) cortex that are specialized for processing face and gaze information. However, it is also the case that top-down factors may modulate the activation of IT cells. Here we examined behaviorally whether reflexive social orienting is purely automatic or sensitive to top-down modulation. Participants were shown an ambiguous stimulus that could be perceived either as representing EYES or a CAR. In we demonstrated between groups that an automatic shift of attention, equivalent to that triggered by a schematic FACE, occurred only when the stimulus was referred to as possessing EYES. In all participants received the EYES and CAR conditions. When the stimulus was first referred to as a CAR and then as EYES, an attentional shift was only present for the EYES condition. However, when the stimulus was first referred to as possessing EYES, and then later as a CAR, attentional shifts were observed for both conditions. These data indicate that the emergence of a reflexive social attention effect is influenced by top-down mechanisms but in an asymmetrical manner. Top-down processes appear to be effective for triggering IT involvement, that is, for perceiving a stimulus as a face, which produces the social attention effect. But top-down mechanisms are ineffective once IT involvement has been triggered. That is, once a stimulus has been seen as having eyes, it continues to be seen that way, and accordingly, the social attention effect persists.

Attention↗
PubMed2006

Pain catastrophizing, but not injury/illness sensitivity or anxiety sensitivity, enhances attentional interference by pain.

UNLABELLED: Pain draws on attentional resources, thereby disturbing the pursuit of ongoing activities. Several studies have made use of the primary task paradigm to study the disruptive function of pain on attention. In this paradigm, participants perform an attentionally demanding task, while they are occasionally distracted by mild electrical stimulation. Deterioration in task performance (in terms of speed and accuracy) is then taken as an index of attentional interference. One major finding with this paradigm was that pain catastrophizing enhances attentional interference. The current study aimed to replicate this finding and to explore the possible influence of anxiety sensitivity and injury/illness sensitivity on attentional interference. Healthy volunteers (n = 48) performed an auditory discrimination task and were thereby occasionally distracted by low electrocutaneous stimulations. The performance on the discrimination task was subsequently related to participants' scores on the Pain Catastrophizing Scale, the Anxiety Sensitivity Index, and the Injury/illness Sensitivity Index. We were unable to demonstrate an association of either injury/illness sensitivity or anxiety sensitivity with attentional interference. Results did, however, confirm the finding that pain catastrophizing enhances attentional interference. PERSPECTIVE: The present study showed that pain disrupts ongoing activities. This effect is enlarged in those with high levels of pain catastrophizing and is related to the threatening nature of pain stimuli. The role of anxiety sensitivity and injury/illness sensitivity seems to differ from the role of catastrophizing and needs further research.

Adolescent↗
PubMed2006

A contextual analysis of attention to chronic pain: what the patient does with their pain might be more important than their awareness or vigilance alone.

UNLABELLED: It is often believed that to feel greater pain is to experience greater effects of that pain, and that attention and awareness represent the transmission mechanism in this relationship. By implication, it is assumed that if attention and awareness can be lessened, the effects of pain will likewise reduce. Despite conceptual work and data suggesting more complex processes might indeed be in place, these long-standing and intuitively appealing ideas remain, either explicitly or implicitly, in both research and clinical applications. The purpose of this study was to compare the role of attentional processes in chronic pain with a process that is more contextual, functional, and behavior-focused, namely, acceptance. The hypothesis tested is whether it is more important to understand the amount of contact an individual has with pain, in this case awareness and vigilance to pain, or the degree of influence on behavior brought with that contact, in this case acceptance. Data from 227 patients seeking treatment for chronic pain were examined. Results from correlation analyses showed that acceptance scores achieved stronger correlations than scores for the attention variables with measures of cognitive, emotional, social, and physical functioning. When acceptance of pain was taken into account in multiple regression analyses, scores from the attention measures accounted for little or no variance in measures of patient functioning. The value of various mental, mechanical, behavior-focused, and contextual models of attention in chronic pain is discussed. PERSPECTIVE: Attention, awareness, and vigilance appear immediately applicable for understanding chronic pain. These processes, however, might be incomplete in accounting for pain-related suffering and disability. Acceptance is proposed as a process that expands the framework of attention to include varying cognitive, emotional, and social influences exerted by pain on patient behavior.

Adaptation, Psychological↗
PubMed2006

The micro-structure of attention.

We investigate three possible methods of specifying the microstructure of attention feedback: contrast gain, additive and output gain, using simple single node and 3-layer cortical models composed of graded or spiking neurons. Contrast gain and additive attention are also tested in a spiking network which is simplified by mean field methods. The simulation task uses two stimuli, probe and reference, presented singly or together within the neuronal receptive fields whilst attention is directed towards or away from the receptive field. Model neurons are differentially activated in the different stimuli and attention and equilibrium potentials or average firing rates recorded depending on neuron type are recorded. We compare results for the different modes of attention and architectures with experimental single cell recordings which show how neuronal firing rates change in response to attention, with a bias towards neurons that respond more effectively to the attended stimulus, to investigate which attentional method best fits the experimental data. The simulation results are also mathematically analysed. We conclude that there is most experimental support for contrast gain, although some additional feedback gain would be possible. We propose a tentative method by which attention as contrast gain may occur in the primate brain using acetylcholine and nicotinic receptors.

Animals↗
PubMed2005

Control networks and hemispheric asymmetries in parietal cortex during attentional orienting in different spatial reference frames.

Neuropsychological research has consistently demonstrated that spatial attention can be anchored in one of several coordinate systems, including those defined with respect to an observer (viewer-centered), to the gravitational vector (environment-centered), or to individual objects (object-centered). In the present study, we used hemodynamic correlates of brain function to investigate the neural systems that mediate attentional control in two competing reference frames. Healthy volunteers were cued to locations defined in either viewer-centered or object-centered space to discriminate the shape of visual targets subsequently presented at the cued locations. Brain responses to attention-directing cues were quantified using event-related functional magnetic resonance imaging. A fronto-parietal control network was activated by attention-directing cues in both reference frames. Voluntary shifts of attention produced increased neural activity bilaterally in several cortical regions including the intraparietal sulcus, anterior cingulate cortex, and the frontal eye fields. Of special interest was the observation of hemispheric asymmetries in parietal cortex; there was significantly greater activity in left parietal cortex than in the right, but this asymmetry was more pronounced for object-centered shifts of attention, relative to viewer-centered shifts of attention. Measures of behavioral performance did not differ significantly between the two reference frames. We conclude that a largely overlapping, bilateral, cortical network mediates our ability to orient spatial attention in multiple coordinate systems, and that the left intraparietal sulcus plays an additional role for orienting in object-centered space. These results provide neuroimaging support for related claims based on findings of deficits in object-based orienting in patients with left parietal lesions.

Adolescent↗