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At least 721 records · Page 40Linked to original sources
PubMed2005

Delayed attentional engagement in the attentional blink.

Observers often miss the 2nd of 2 visual targets (first target [T1] and second target [T2]) when these targets are presented closely in time; the attentional blink (AB). The authors hypothesized that the AB occurs because the attentional response to T2 is delayed by T1 processing, causing T2 to lose a competition for attention to the item that follows it. The authors investigated this hypothesis by determining whether the AB is attenuated when T2 is precued. The results from 4 experiments showed that the duration and magnitude of the AB were substantially reduced when T2 was precued. The observed improvement in T2 report did not occur at the expense of T1 report, suggesting that processing of T1 was already completed or was at least protected when the cue was presented. The authors conclude that, during the AB, there is a delay between detection and the selection of target candidates for consolidation in short-term memory.

Attention↗
PubMed2004

Identification facilitation for emotionally arousing verbs during the attentional blink.

The present study aimed to examine affective modulation of the "attentional blink" effect during rapid serial visual presentation (RSVP). Pleasant, neutral, and unpleasant written verbs were used as a 2nd target (T2) in an 8.6-Hz RSVP paradigm. Pronounced effects of 1st target (T1)-T2 stimulus onset asynchrony (SOA) were found, showing reduced report accuracy for 232- and 464-ms SOAs. Affectively arousing (pleasant and unpleasant) T2s were associated with enhanced accuracy compared with neutral T2s specifically during short (232 ms) SOAs. In contrast, pleasant and unpleasant T2s rated low in terms of emotional arousal did not show this enhancement. These results suggest that affectively arousing information is selected preferentially from a temporal stream, facilitating processes such as working memory consolidation and action.

Adult↗
PubMed2006

Parameterizing the attentional blink effect.

The attentional blink effect (AB) is used to examine the limits of attention in dual-task paradigms. However, since the effect is nonlinear, it is sometimes difficult to characterize the results. Furthermore, it is difficult to assess the significance of the effect between groups because the results are highly variable both within and across subjects. In this paper, we propose a method to quantify four characteristics of the AB curve: the minimum performance, the amplitude between the minimum and the asymptotic performance, the amount of Lag-1 sparing, and the width of the effect. The method, based on curve fitting, allows easier comparisons of the results across experiments, can test only one characteristic at a time, and yields more powerful statistical tests.

Attention↗
PubMed2005

The time course of the contingent spatial blink.

Attentional capture is the unintentional deployment of attention to a task-irrelevant but attentionally salient object. The contingent involuntary orienting hypothesis states that it occurs only if a distractor's property matches current top-down attentional control settings (Folk, Remington, & Johnston, 1992). Folk, Leber, and Egeth (2002) found that monitoring a central RSVP stream for a coloured target led to spatial attentional capture by a peripheral distractor that matched the target colour. Using a similar paradigm, we explored the time course of this spatial blink. Implications of this study for current accounts of the attentional capture phenomenon are discussed.

Adult↗
PubMed2005

Timing of the brain events underlying access to consciousness during the attentional blink.

In the phenomenon of attentional blink, identical visual stimuli are sometimes fully perceived and sometimes not detected at all. This phenomenon thus provides an optimal situation to study the fate of stimuli not consciously perceived and the differences between conscious and nonconscious processing. We correlated behavioral visibility ratings and recordings of event-related potentials to study the temporal dynamics of access to consciousness. Intact early potentials (P1 and N1) were evoked by unseen words, suggesting that these brain events are not the primary correlates of conscious perception. However, we observed a rapid divergence around 270 ms, after which several brain events were evoked solely by seen words. Thus, we suggest that the transition toward access to consciousness relates to the optional triggering of a late wave of activation that spreads through a distributed network of cortical association areas.

Adolescent↗
PubMed1999

Midazolam effects on prepulse inhibition of the acoustic blink reflex.

AIMS: The eye-blink response following sudden acoustic noise bursts is part of the startle reflex. The magnitude of the startle response can be attenuated by presentation of a weak stimulus before the 'startle-eliciting' stimulus (prepulse inhibition, PPI). PPI is a stable finding in awake humans but may be altered by anaesthetic drugs. We investigated whether the application of benzodiazepines altered the magnitude of PPI in healthy male volunteers. METHODS: In an open-label noncontrolled investigation, the effect of the benzodiazepine agonist midazolam on PPI was assessed in the absence and presence of the antagonist flumazenil. After an initial control period of 60 min three consecutive periods, each of 60 min, with progressively increasing concentrations of midazolam were studied (0. 02, 0.06, 0.14 mg kg-1 h-1 ). A final 60 min period during the administration of flumazenil (0.004 mg kg-1 h-1 ) and while the agonist was still present was also studied. Drug was administered intravenuously as a combination of bolus, 50% of total dose and continuous infusion over the 60 min period. Electromyographic (EMG) response of the right orbicularis oculi muscle was used to assess the startle response to noise bursts of 50 ms duration (95 dB(A)). Noise bursts were randomly preceded by nonstartling prepulses (800 Hz sinus, 50 ms duration, 65 dB(A), prepulse to noise interval 120 ms). The magnitude of PPI was calculated by dividing the EMG response to nonprepulsed stimuli by the response to prepulsed stimuli for each individual and period. Eleven subjects participated in the study, two of them were excluded from the statistical analysis because startle responses could not be reliably elicited (final sample size n=9). RESULTS: The magnitude of PPI was inversely related to the concentration of midazolam. This relationship was described by a sigmoidal Emax model, giving an Emax of 0.65+/-0.13, an ED50 of 33.9+/-10.9 ng ml-1 and gamma of 3.5+/-1.0. During infusion of flumazenil and in the presence of midazolam, the magnitude of PPI increased by 0.11 (95% CI, 0-0.22, P</=0.04), which is consistent with its mode of action as a benzodiazepine antagonist. CONCLUSIONS: In healthy male volunteers the magnitude of PPI varies according to agonism and antagonism of benzodiazepine receptors, suggesting that the assessment of PPI may be potentially useful to monitor the sedative effect of benzodiazepines in the clinical setting.

Acoustic Stimulation↗
PubMed2002

Blink rate variability in patients with panic disorder: new trial using audiovisual stimulation.

Several lines of evidence have implicated central dopaminergic pathways in the modulation of spontaneous blink rate (BR). Furthermore, previous studies have indicated a relationship between spontaneous BR and anxiety and/or depression. However, to our knowledge, there is no report on the examination of BR in a group of patients with panic disorder (PD). During the conditions of rest and with audiovisual stimulation, exposed to a video of imaginary experiences, such as driving a motor vehicle or diving into the sea, BR was examined in 11 male patients with PD and compared with the BR of 16 age-matched normal controls. The BR was significantly higher in PD patients relative to normal controls under both conditions. In particular, the PD group had a higher BR score during the sea scene as relaxation compared with the normal controls. In conclusion, although the sample size was small the present preliminary study, these findings suggest that BR may have potential for application in the assessment of anxiety state, which is consistent with previous studies.

Adult↗
PubMed1999

Short-lasting conditioned stimulus applied to the middle cerebellar peduncle elicits delayed conditioned eye blink responses in the decerebrate ferret.

In delay eye blink conditioning, the conditioned stimulus (CS) ends at the time of the unconditioned stimulus (US). If the CS duration is decreased, there will be a 'trace' period with no ongoing CS before the onset of the US. During this period some neural activity has to continue after the CS offset to: (i) permit association between the CS and the US; and (ii) elicit a conditioned response appearing after the CS offset. In this study we test the role of the cerebellum in maintaining CS activity required for eliciting a conditioned response after the CS offset. Decerebrate ferrets were trained in a delay conditioning paradigm with an electrical stimulation of the forelimb as CS and of the periorbital area as US. The conditioned responses in the upper eyelid were monitored with electromyographical techniques. In well-trained animals, test CSs of short duration down to 0.2 ms were applied to the forelimb or the middle cerebellar peduncle, while the interstimulus interval between CS onset and US onset was kept constant at 300 ms. Test CSs of short duration applied to the forelimb elicited conditioned responses. More importantly, also a short-lasting CS to the middle cerebellar peduncle could elicit conditioned responses. The results indicate that precerebellar CS pathways are not required for maintaining the neural activity that elicits conditioned responses after the CS offset. It is suggested that neurons maintaining such activity are located in the cerebellum, either the cortex alone or the cortex and the deep nuclei.

Animals↗
PubMed1992

The blink reflex in migraine.

The blink reflex is an objective and useful method to study the trigeminal system. It was recorded in 43 migraine patients and the findings compared with those of 31 healthy controls. The latencies of the R1 component were in the normal range in both groups. The R2 latencies ranged between 30 and 32 ms in the control group. In contrast, more than half of the patients with migraine had R2 latencies between 32 and 35 ms in the migraine group. Some migraine patients had latencies above 35 ms. The R2 latency was statistically significantly different between controls and migraineurs (p < 0.0001). Our findings indicate that trigeminal afferents and/or polysynaptic pathway in brainstem may be altered in migraine.

Adolescent↗
PubMed1994

The blink reflex in chronic tension-type headache, migraine, and cervicogenic headache.

R1 and R2 blink reflex latencies were investigated blind in 10 patients with cervicogenic headache, 11 patients with chronic tension-type headache, 11 patients with migraine, and 9 headache-free controls. There were no R1 or R2 latency differences between the four groups. The latency of R1 increased significantly with headache duration in tension-type headache patients. Shorter R1 latencies were found on the symptomatic side than on the non-symptomatic side in cervicogenic headache patients. The results suggest that a state of hyperactivity may be present in the ipsilateral trigeminal nucleus in cervicogenic headache. Hypoactivity, however, may develop over time in tension-type headache.

Adult↗
PubMed2003

Abnormal habituation of 'nociceptive' blink reflex in migraine--evidence for increased excitability of trigeminal nociception.

We studied the habituation of the 'nociceptive' blink reflex (nBR) in 15 healthy subjects and 17 migraine patients interictally as well as during unilateral migraine headache within six hours of onset and after treatment. In healthy volunteers the mean regression coefficient (MRC) was - 3.9 following right sided and - 4.9 left sided stimulation. This equals an amplitude loss of 19.5% (5 x -3.9) and 24.5% (5 x -4.9), respectively, across five consecutive sweeps. An augmentation of nBR responses was found in migraine patients interictally: MRC = 3.3 following stimulation of the headache side (HA) and MRC = 4.0 of the non-headache side (non-HA). The differences were statistically significant (anova: d.f. = 1, F = 25.8, P < 0.001). During the migraine attack MRCs were negative both before (-5.0, HA and - 4.0, non-HA) and after treatment (-2.6, HA and - 1.9 non-HA) and significantly differed from those outside the migraine attack (anova: d.f. = 2, F = 12.4, P < 0.001). The demonstrated lack of habituation of the nBR responses indicates an abnormal trigeminal nociceptive processing in migraine patients outside the migraine attack.

Adult↗
PubMed2003

Dual target identification and the attentional blink in Parkinson's disease.

In healthy adults, deficits in identifying a second target following a previously attended target in Rapid Serial Visual Presentation (RSVP) occur between intertarget intervals of approximately 100-500 ms. This Attentional Blink (AB) is investigated in nondemented medicated Parkinson's patients using a modification of the standard paradigm that required the identification of two red letters embedded in a black letter distractor stream. Parkinson's patients and controls produced an equivalent AB, although with a different pattern of errors. Thus, the processing and clearance of information was largely preserved in nondemented Parkinson's patients, without evidence of bradyphrenia. However, perseveration of earlier RSVP items in short-term memory was thought to explain the different pattern of errors.

Aged↗
PubMedDate not supplied

Blink reflex latency after exposure to trichloroethylene in well water.

The electrophysiological measurement of the blink reflex (BR) can quantify the conduction latency in the reflex arc involving the Vth (trigeminal) and VIIth (facial) cranial nerves. We measured the electrophysiological BR in a population (N = 21), which had alleged chronic exposure to trichloroethylene (TCE) through the public drinking water at levels 30-80 times higher than the Environmental Protection Agency (EPA) Maximum Contamination Level (MCL). A highly significant difference was observed in the conduction latency means of the BR components (p less than .0001), when the study population was compared with laboratory controls (N = 27). This difference suggests a subclinical alteration of the Vth cranial nerve function due to chronic, environmental exposure to TCE.

Adult↗
PubMed2000

Evidence for distinct attentional bottlenecks in attention switching and attentional blink tasks.

E. Weichselgartner and G. A. Sperling (1987), using rapid serial visual presentation (RSVP), estimated that attention could be moved to a new spatial location within 300-400 ms. H. J. Müller and P. M. Rabbit (1989) used a spatial cuing task and found a similar time course for voluntarily redeploying attention. A separate phenomenon known as the attentional blink (AB) also follows a similar time course, yet occurs when participants attend to a single spatial location. The present study found that attention can be shifted more quickly than previously estimated and that part of the deficit observed during searches of spatially distinct RSVP streams is due to an AB. The results support some early and late selection accounts for the temporal dynamics of visual attention and suggest different bottlenecks during visual selection. The implications for visual search and visual processing are discussed.

Attention↗
PubMed2004

The attentional blink is susceptible to concurrent perceptual processing demands.

In a rapid serial visual presentation stream processing of a first target (T1) impairs detection or identification of a second target (T2) that appears within 500 ms after T1. This effect characterizes the so-called attentional blink (AB). To evaluate contemporary information-processing accounts of the AB phenomenon in terms of the underlying processing mechanisms the present study examined the potential influence of Task 1 difficulty on the AB effect. To this end, T1 contrast and T1 response requirements were systematically varied across four experiments. Experiment 1 ruled out a mere sensory basis of the contrast manipulation on T2 performance. When only T2 had to be reported (Experiment 2) an AB effect occurred that was slightly modulated by T1 contrast. When report of both T1 and T2 was required in a standard AB task (Experiment 3), the magnitude of the AB depended to a larger extent on stimulus contrast, and it increased further when speeded T1 choice responses were additionally required (Experiment 4). On the basis of the present impact of Task 1 difficulty on the AB effect we conclude that processing limitations cause the AB phenomenon. We discuss such limitations in terms of perceptual (T1 consolidation) and central (response selection) bottleneck processes.

Adult↗
PubMedDate not supplied

Cognitive and attentional changes with age: evidence from attentional blink deficits.

The attentional blink (AB) is a marked deficit in detecting a second target for up to 600 ms within a rapid serial visual presentation (RSVP). The phenomenon of the AB has typically been investigated using college students between 18 and 25 years of age. However, the AB has not been closely studied within a senior population. Past studies have found age-related attentional deficits using cued location, visual conjunction search, and divided-attention tasks, all spatial measures of attention; however, the physiological basis of these deficits is not fully understood. The role of cognitive slowing and reduced attentional resources was examined using the AB paradigm--a temporal measure of attention. Experiment 1 found an age-related deficit independent of lag for the single-task condition and a larger more prolonged deficit for dual-task conditions. Experiment 2, using similar methods to Experiment 1, incorporated a more rigorous cognitive screen. A similar deficit was found for the dual-task condition. However, single-task trials appeared to involuntarily capture attentional resources for the older population. Comparisons revealed a significant difference in the magnitude and the time course of the AB with age. Results are discussed in the context of cognitive slowing and reduced attentional resources.

Adolescent↗
PubMed2002

A comparison between schizophrenia patients and healthy controls on the expression of attentional blink in a rapid serial visual presentation (RSVP) paradigm.

The expression of attentional blink (AB) in 24 schizophrenia inpatients was compared to 22 healthy subjects in a dual-target rapid serial visual presentation (RSVP) paradigm in which a sequence of discrete stimuli was presented in rapid succession. Correct identification of the first target led to poorer detection of the second one when they were interspersed by distractors. This second-target deficit constitutes the AB effect, which is most pronounced between 200 and 500 ms after the offset of the first target stimulus and steadily decays as the number of intervening distractors increases. Despite relatively poor performance in terms of target identification within RSVP streams, schizophrenia patients expressed an AB effect that was as clear as that seen in healthy subjects. Moreover, there was evidence for an enhanced AB effect in schizophrenia patients. This outcome contrasts with the robust finding that schizophrenia patients are attenuated in the expression of prepulse inhibition, another paradigm believed to assess attentional control. The present results add to the extensive literature on the nature and specification of attentional dysfunction implicated in schizophrenia.

Adult↗
PubMed1997

The effects of tobacco smoking on the short, middle, and long latency responses of the blink reflex in humans.

The three responses (R1, R2, and R3) of the electrically elicited blink reflex (BR) obtained in four normal human subjects were investigated before and after smoking both a filtered and an unfiltered cigarette. The changes observed in the BR were stronger and statistically more significant for the unfiltered than for the filtered cigarette, (p < 0.0001) and were more dramatic in R3 than R1 or R2. The action of nicotine on central pathways located at the interneuronal network of the brainstem, basal ganglia, and C fiber structures involved with this reflex seems to be the most likely mechanism for these findings.

Adult↗