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At least 847 records · Page 47Linked to original sources
PubMed1988

Simple pA2 estimation of partial agonists: comparison with the Kaumann-Blinks method.

Estimation of KB and pA2 of partial agonists as antagonists of full agonists is hindered by their stimulant component of action. This reflects competitive synergism, i.e., an additive interaction with a full agonist. The antagonistic component of a partial agonist is seen as a parallel shift of the agonist curve to the right from a constructed additive dose-response curve, from which a dose ratio (DR) was determined for calculation of graphic estimation of KB or pA2 of partial agonists. Dose-response curves from eight studies were analyzed in this way, in comparison with the method of Kaumann and Blinks, and showed excellent agreement between pA2 values determined by either method (r = 0.994, slope = 0.999, n = 17).

Albuterol↗
PubMed2005

Target integration and the attentional blink.

If people monitor a visual stimulus stream for targets they often miss the second (T2) if it appears soon after the first (T1)--the attentional blink. There is one exception: T2 is often not missed if it appears right after T1, i.e., at lag 1. This lag-1 sparing is commonly attributed to the possibility that T1 processing opens an attentional gate, which may be so sluggish that an early T2 can slip in before it closes. We investigated why the gate may close and exclude further stimuli from processing. We compared a control approach, which assumes that gate closing is exogenously triggered by the appearance of nontargets, and an integration approach, which assumes that gate closing is under endogenous control. As predicted by the latter but not the former, T2 performance and target reversals were strongly affected by the temporal distance between T1 and T2, whereas the presence or the absence of a nontarget intervening between T1 and T2 had little impact.

Adult↗
PubMed2004

Right hemisphere involvement in the attentional blink: evidence from a split-brain patient.

When two masked targets are presented in a rapid sequence, correct identification of the first hinders identification of the second. This attentional blink (AB) is thought to be the result of capacity limitations in visual information processing. Neuropsychological and neuroimaging evidence implicated the right hemisphere as the source of this processing limitation. We investigated this idea by testing a split-brain patient (JW) in a modified AB task. The targets were presented in the same visual field (VF), and thereby to the same hemisphere, or in different VFs. We observed evidence of an AB both when the targets were presented to the same hemisphere and when the targets were presented to different hemispheres. However, the AB was more severe when the second target was presented to the RH. Our results are consistent with the notion that the right hemisphere plays a critical, but not unique, role in limited-capacity visual processing.

Attention↗
PubMed2004

Seeing the light: Adapting luminance reveals low-level visual processes in the attentional blink.

It is widely assumed that high-level visual processes subserve the attentional blink (AB). Recent evidence from studies of visual masking during the AB that were designed to directly test the contributions of high-level masking effects, however, have failed to provide empirical support for this position. The implication is that low-level visual processes are crucial to the AB. We tested this idea by manipulating adapting luminance in a standard AB paradigm. Consistent with the involvement of low-level neural mechanisms, the AB effect interacted with adapting luminance such that an AB was revealed only under photopic (light adapted) viewing conditions.

Adaptation, Ocular↗
PubMed2005

Attentional blink differences between adolescent dyslexic and normal readers.

The goal of this study was to evaluate the possibility that dyslexic individuals require more working memory resources than normal readers to shift attention from stimulus to stimulus. To test this hypothesis, normal and dyslexic adolescents participated in a Rapid Serial Visual Presentation experiment (Raymond, Shapiro, & Arnell, 1992). Surprisingly, the result showed that the participants with dyslexia produced a shallower attentional blink than normal controls. This result may be interpreted as showing differences in the way the two groups encode information in episodic memory. They also fit in a cascade-effect perspective of developmental dyslexia.

Adolescent↗
PubMed2006

The attentional blink reveals sluggish attentional shifting in adolescents with specific language impairment.

Rapid processing deficits have been the subject of much debate in the literature on specific language impairment (SLI). Hari and Renvall (2001) [Hari, R. & Renvall, H. (2001). Impaired processing of rapid stimulus sequences in dyslexia. Trends in cognitive sciences, 5, 525-532.] proposed that the source of this deficit can be attributed to sluggish attentional shifting abilities. That is, more time is required to shift attention between stimuli. To test this claim, 26 adolescents with SLI (divided into two subgroups to control for differences in non-verbal intelligence) and 14 controls were presented with a rapid serial visual presentation task. In this task participants were asked to detect two visual targets presented serially with distracter items with varying inter-target intervals (i.e., time difference between targets). This task was designed to elicit an attentional blink (AB). The AB describes the phenomenon whereby non-impaired individuals are less likely to report the second of two targets presented within 200-500ms of each other. After controlling for group differences in non-verbal intelligence, the SLI group was found to be significantly less accurate than the control group at successfully reporting the second target at inter-target intervals of 100, 200, 300, 400 and 800ms. The results were interpreted to suggest that adolescents with language impairments have an AB which differs from non-impaired individuals in both magnitude and duration.

Adolescent↗
PubMed2006

Exploring the short term visual store in schizophrenia using the attentional blink.

Schizophrenia patients exhibit numerous deficits on visual processing tasks, ranging from very early stages of visual processing (e.g., backward masking) to the later working memory stages (e.g., delayed match-to-sample, N-back). However, little is known about deficits in an intermediate stage of visual information processing, namely short term visual memory (STVM). The attentional blink (AB) paradigm is considered to be a valid way to assess the STVM, and recent studies have reported AB deficits in schizophrenia. However, it is not clear whether the reported AB deficit in schizophrenia patients is due to their increased susceptibility to backward masking or increased vulnerability in the STVM. In this study we first found poorer performance in the AB task in 37 schizophrenia patients compared to 26 normal controls. To examine the effects of increasing and decreasing mask strength on AB performance in patients and controls, we next systematically varied the masking effect by varying the length of the distracters immediately following the targets. The manipulation had relatively little effect on the patient--control differences and patients continued to show an enhanced AB effect across conditions. The findings suggest that the enhanced AB effect in schizophrenia reflects an abnormality in their short term visual memory, as opposed to their enhanced susceptibility to visual masking.

Adult↗
PubMed1970

The Haxo and Blinks electrode. A mathematical model.

Fick's diffusion equations have been solved for the Haxo and Blinks electrochemical determination of photosynthetic O(2) evolution. The model shows the method to be quantitative in the case of a "long" chamber measuring constant rates of O(2) evolution. Transients are amplitude distorted by an amount depending on the space distribution of the O(2) sources. A correction equation applied to the raw data permits the recovery of the original signal.

Diffusion↗
PubMed2002

The attentional blink in space and time.

We report the results of two experiments addressing spatiotemporal variations in the "attentional blink" (AB). In the first experiment, six streams of letters were presented simultaneously around a circle on a screen. The identity of the letters changed every 140 ms. The task was to identify two target digits (T1 and T2) that could appear in any of the streams with a variable time lag between the two. The results show that the AB is not constant across space and that following the allocation of attention to a certain location (the location of T1), discrimination can be better at locations quite far away from T1, than at locations closest to T1. Furthermore, performance at the farthest locations seemed to recover sooner from the AB than locations closer to where T1 appeared. Similar results were obtained in a second experiment where observers performed a cued discrimination task. The results accord well with the proposal that there is a region around the attended site (the center of attention) where attentional resolution is particularly poor, worse than at sites further away from the attended one. We propose that this reflects lateral inhibition of neurons responsive to the region around the attended site, with the goal of suppressing potentially distracting or interfering information.

Adult↗
PubMed2000

Neural correlates of the attentional blink.

Attending to a visual event can lead to functional blindness for other events in the visual field. This limit in our attentional capacities is exemplified by the attentional blink (AB), which refers to the transient but severe impairment in perceiving the second of two temporally neighboring targets. Using functional magnetic resonance imaging (fMRI), we observed predominantly right intraparietal and frontal cortex activations associated with the AB. We further demonstrate that an AB can be elicited by both temporal and spatial distractor interference on an attended target and that both of these interference mechanisms activate the same neural circuit. These results suggest that a (right) parietofrontal network previously implicated in attentional control and enhancement is also a locus of capacity-limited processing of visual information.

Adult↗
PubMed1994

Attention to visual pattern information produces the attentional blink in rapid serial visual presentation.

To-investigate the temporal allocation of attention, a series of 7 experiments using rapid serial visual presentation (RSVP) was designed to examine the relationship of the attentional demands of various target tasks to the production of the subsequent visual attentional deficit, or "attentional blink" (AB), recently reported by J. E. Raymond, K. L. Shapiro, and K. M. Arnell (1992). The principal finding is that AB occurs only when a target is an object and does not occur when the target is defined by a temporal interval. Target detection difficulty as estimated by d' analysis reveals no relationship between the attentional demands of the target and the production of the AB. A late-selection account of this phenomenon is offered in place of the early-selection account advanced in Raymond et al.'s previous report.

Adult↗
PubMed1997

Personal names and the attentional blink: a visual "cocktail party" effect.

Four experiments were carried out to investigate an early- versus late-selection explanation for the attentional blink (AB). In both Experiments 1 and 2, 3 groups of participants were required to identify a noun (Experiment 1) or a name (Experiment 2) target (experimental conditions) and then to identify the presence or absence of a 2nd target (probe), which was their own name, another name, or a specified noun from among a noun distractor stream (Experiment 1) or a name distractor stream (Experiment 2). The conclusions drawn are that individuals do not experience an AB for their own names but do for either other names or nouns. In Experiments 3 and 4, either the participant's own name or another name was presented, as the target and as the item that immediately followed the target, respectively. An AB effect was revealed in both experimental conditions. The results of these experiments are interpreted as support for a late-selection interference account of the AB.

Adolescent↗
PubMed1998

Beyond the attentional blink: visual masking by object substitution.

If 2 targets are to be identified among distractors displayed in rapid sequence, correct identification of the 1st target hinders identification of the 2nd. To obtain this attentional blink (AB), the 1st target must be masked with a simultaneous (integration) or a delayed (interruption) mask indifferently. In 3 experiments, it was shown that the 2nd target must also be masked, but that the precise form of masking is important: An AB occurs with interruption but not with integration masking. This nonequivalence of masking paradigms parallels that found in studies of masked priming, a phenomenon arguably related to the AB. The results are explained by a revised 2-stage model (M. M. Chun & M. C. Potter, 1995).

Adult↗
PubMed2001

The influence of temporal selection on spatial selection and distractor interference: an attentional blink study.

Both spatial and temporal selection require focused attention. The authors examine how temporal attention affects spatial selection. In a dual-task rapid serial visual presentation paradigm, temporal selection of a target (T1) impairs processing of a second target (T2) that follows T1 within 500 ms. This process is the attentional blink (AB). To test the effects of withdrawing temporal attention, the authors measured concurrent distractor interference on T2 when the distractors were presented during and outside of the AB. Perceptual interference was manipulated by the similarity in color between T2 and concurrent distractors, and response interference was manipulated by the flanker congruency task. Results showed that perceptual interference was larger during the AB. Response interference also increased during the AB, but only when perceptual interference was high. The authors conclude that temporal selection and spatial selection rely on a common attentional process.

Adult↗
PubMed2002

Loci of signal probability effects and of the attentional blink bottleneck.

To investigate the locus of signal probability effects and the influence of stimulus quality on this locus, the authors manipulated probability in Task 2 of a psychological refractory period (PRP) paradigm. The effect was additive with stimulus onset asynchrony (SOA) when the target was not masked but underadditive with decreasing SOA when the target was masked. Even with masking, however, a range of probabilities had effects additive with SOA. The results suggest loci of stimulus probability before the PRP bottleneck as well as at or after the bottleneck. A second issue addressed was the locus of interference in the attentional blink (AB). The AB was larger when the probability of the first of 2 targets was lower. The results lead to the conclusion that one cause of the AB effect is a locus at least as late as the PRP bottleneck.

Attention↗
PubMed2003

Visual masking during the attentional blink: tests of the object substitution hypothesis.

When 2 masked targets are presented in a rapid sequence, correct identification of the 1st hinders identification of the 2nd. Visual masking of the 2nd target plays a critical role during this 2nd-target deficit, or "attentional blink" (AB). The object substitution hypothesis (B. Giesbrecht & V. Di Lollo, 1998) predicts that late-stage visual processes involved in object substitution mediate masking of the 2nd target during AB, whereby stronger masking should produce a more severe deficit. Six experiments are presented, together testing this hypothesis. Although masking by object substitution was observed, it did not interact with the AB. An alternative hypothesis is proposed stating that mostly early-stage visual processes mediate the masking effects that are critical to the AB.

Adult↗
PubMed1979

The eye blink as a time-locked response: implications for serial and second-order conditioning.

A series of experiments were conducted to determine what factors control responding to the first element of a two-element serial compound in rabbit eyelid conditioning. An examination of response topography indicated that the eye-blink CR is rigidly timed to occur when the US is expected. This response-system characteristic prevents the occurrence of a CR during the first element of a serial compound or during the second-order CS in second-order conditioning. The comparison of a serial gap procedure with conventional serial and trace conditioning procedures suggested that the associative strength of the first element of a serial CS is not strongly influenced by either a second-order conditioning process or by the variable-reinforcement principle.

Animals↗
PubMed1998

Two attentional deficits in serial target search: the visual attentional blink and an amodal task-switch deficit.

When monitoring a rapid serial visual presentation at 100 ms per item for 2 targets among distractors, viewers have difficulty reporting the 2nd target (T2) when it appears 200-500 ms after the onset of the 1st letter target (T1): an attentional blink (AB; M. M. Chun & M. C. Potter, 1995b; J. E. Raymond, K. L. Shapiro, & K. M. Arnell, 1992). Does the same deficit occur with auditory search? The authors compared search for auditory, visual, and cross-modal targets in 2 tasks: (a) identifying 2 target letters among digits (Experiments 1-3 and 5) or digits among letters (Experiment 6), and (b) identifying 1 digit among letters and deciding whether an X occurred among the subsequent letters (Experiment 4). In the experiments using the 1st task, the standard AB was found only when both targets were visual. In the 2nd task, with a change in selective set from T1 to T2, a task-switching deficit was obtained regardless of target modality.

Adult↗