Nontarget Cues Research Articles

No difference in prior representations of what to attend and what to ignore

ABSTRACT Adaptive behaviour requires the selection of relevant, and the ignoring of irrelevant visual information. Previous work has shown that prior information about target (i.e., relevant) and non-target (i.e., irrelevant) objects facilitates such selection, presumably by enabling observers to create a working memory template for or against such objects. Using a cued visual search task, here we aimed to investigate whether, and how, target and non-target templates differ in terms of neural representation, as measured through fMRI activity patterns. Two hypotheses were tested: (1) while target representations are activated, non-target representations are suppressed prior to search, and thus these representations differ, and (2) target and non-target templates share similar initial representations but involve different control signals in anticipation of, or upon encountering the search display. Behaviourally, both target and non-target cues facilitated search compared to baseline. Using multivariate pattern and representational similarity analyses, the findings revealed little support for the suppression hypothesis. Posterior brain regions primarily coded for the category content of the template and did so similarly for target and non-target information. Frontal cortical areas, particularly the lateral prefrontal cortex and frontal eye fields, instead showed sensitivity to the status of the template, regardless of the object category it belonged to. These results are most consistent with the hypothesis that prior to selection, target and non-target information are represented similarly in terms of content, but differ in terms of the associated control signals.

No evidence for proactive suppression of explicitly cued distractor features.

Visual search benefits from advance knowledge of nontarget features. However, it is unknown whether these negatively cued features are suppressed in advance (proactively) or during search (reactively). To test this, we presented color cues varying from trial-to-trial that predicted target or nontarget colors. Experiment 1 (N = 96) showed that both target and nontarget cues speeded search. To test whether attention proactively modified cued feature representations, in Experiment 2 (N = 200), we interleaved color probe and search trials and had participants detect the color of a briefly presented ring that could either match the cued color or not. People detected positively cued colors better than other colors, whereas negatively cued colors were detected no better or worse than other colors. These results demonstrate that nontarget features are not suppressed proactively, and instead suggest that anticipated nontarget features are ignored via reactive mechanisms.

Reversing the relationship between a nontarget cue and the outcome facilitates subsequent human predictive learning

Two experiments were conducted to test the effect of experiencing associative interference on later learning. A predictive learning task was used in which human participants had to evaluate whether plants would grow or not (Outcome) after being watered with different fertilizers (Cues). Experiment 1 found that the increase in the prediction error produced by following a pre-exposed nontarget cue by the outcome, facilitated subsequent acquisition of the relationship between the pre-exposed target cue and the outcome. Experiment 2 compared whether learning about the target cue was differentially affected by experiencing two types of associative interference with the nontarget cue: Pairing the pre-exposed cue with the outcome and presenting the cue without outcome after being paired with it. The experience of associative interference with nontarget cues similarly facilitated subsequent learning about the target cue, regardless of the direction of the change in the nontarget cue-outcome relationship. It is suggested that the increase in prediction error produced by the experience of associative interference may lead to a general increase in attention that facilitates subsequent learning.

108 Attentional Control Deficits during Total Sleep Deprivation: Independence from Reduced Vigilant Attention

Abstract Introduction Total sleep deprivation (TSD) has been shown to impair performance on a two-phase attentional control task, the AX-type continuous performance task with switch (AX-CPTs). Here we investigate whether the observed AX-CPTs impairments are a downstream consequence of TSD-induced non-specific effects (e.g., reduced vigilant attention) or reflect a distinct impact on attentional control. Methods N=55 healthy adults (aged 26.0±0.7y; 32 women) participated in a 4-day laboratory study with 10h baseline sleep (22:00-08:00) followed by 38h TSD and then 10h recovery sleep. At baseline (09:00 day 2) and after 25h and 30h TSD (09:00 and 14:00 day 3), subjects were tested on a 10min psychomotor vigilance test (PVT), an assay of vigilant attention, and on the AX-CPTs. The AX-CPTs required subjects to differentiate designated target from non-target cue-probe pairs. In phase 1, target trials occurred frequently, which promoted prepotent anticipatory responses; in phase 2, the target pair was switched. Accuracy of responses to various different AX-CPTs trial types was expressed relative to accuracy on phase 1 neutral (non-target cue and probe) trials, which should capture non-specific impairments on the task. For all three test sessions, these relative accuracy measures, along with accuracy on phase 1 neutral trials and lapses (RT>500ms) on the PVT, were subjected to principal component analysis (PCA). Results The PCA revealed three statistically independent factors. Following varimax rotation, factor 1 (36.3% variance explained) and factor 3 (14.8% variance explained) each had high loadings for relative accuracy on multiple AX-CPTs trial types from phases 1 and 2; whereas factor 2 (17.9% variance explained) had high loadings for accuracy on phase 1 neutral trials, relative accuracy on phase 1 target trials, and PVT lapses. Conclusion These results indicate a statistical separation between AX-CPTs phase 1 neutral trials and phase 1 target trials, in conjunction with PVT lapses, versus the various other AX-CPTs trial types. This suggests a dissociation between TSD-induced, non-specific impairments on the task—potentially related to reduced vigilant attention—and TSD-induced specific impairments related to attentional control. Thus, TSD-induced deficits in attentional control are unlikely to be a downstream consequence of non-specific impairments. Support (if any) CDMRP grant W81XWH-16-1-0319

Potentiation of performance in an Eriksen flanker task

This experiment examined the effects of a redundant cue that predicted the target response to a target stimulus in a response conflict procedure using a flanker task. Participants received trials with five-character arrays with a central target character and distractor flanker characters that matched (compatible) or did not match (incompatible) the central target. Participants’ expectancies for compatible and incompatible trials were manipulated by presenting pre-trial cues that signaled the occurrence of compatible or incompatible trials. Some groups received a single cue predicting the target stimulus and the required target response. Other groups received this cue along with a second redundant, predictive cue. The presence of a second, redundant cue during training in which incompatible trials were predicted facilitated performance (errors were reduced) compared to when only a single cue was present. This finding is consistent with the potentiation effect in conditioning and learning. Extinction of the nontarget cue prior to testing on the target (a retrospective revaluation manipulation) had no effect on performance. The finding of potentiation between pre-trial cues that predict incompatible trials, but not cues that predict compatible trials, suggests that different strategic processes may occur during adaptation to conflict when different kinds of trials are expected.

Effects of Transcranial Magnetic Stimulation Therapy on Evoked and Induced Gamma Oscillations in Children with Autism Spectrum Disorder.

Autism spectrum disorder (ASD) is a behaviorally diagnosed neurodevelopmental condition of unknown pathology. Research suggests that abnormalities of elecltroencephalogram (EEG) gamma oscillations may provide a biomarker of the condition. In this study, envelope analysis of demodulated waveforms for evoked and induced gamma oscillations in response to Kanizsa figures in an oddball task were analyzed and compared in 19 ASD and 19 age/gender-matched neurotypical children. The ASD group was treated with low frequency transcranial magnetic stimulation (TMS), (1.0 Hz, 90% motor threshold, 18 weekly sessions) targeting the dorsolateral prefrontal cortex. In ASD subjects, as compared to neurotypicals, significant differences in evoked and induced gamma oscillations were evident in higher magnitude of gamma oscillations pre-TMS, especially in response to non-target cues. Recordings post-TMS treatment in ASD revealed a significant reduction of gamma responses to task-irrelevant stimuli. Participants committed fewer errors post-TMS. Behavioral questionnaires showed a decrease in irritability, hyperactivity, and repetitive behavior scores. The use of a novel metric for gamma oscillations. i.e., envelope analysis using wavelet transformation allowed for characterization of the impedance of the originating neuronal circuit. The results suggest that gamma oscillations may provide a biomarker reflective of the excitatory/inhibitory balance of the cortex and a putative outcome measure for interventions in autism.

Experiencing extinction with a non-target cue facilitates reversal of a target conditioned inhibitor in human predictive learning

Three experiments tested the effect of experiencing extinction on learning about a differential conditioned inhibitor that was trained as an excitor. A human predictive learning task was used in which participants had to evaluate the probability of different colored fertilizers (Cues) leading plants to flourish or not (Outcome). Experiment 1 found that presenting the target cue without outcome while other cues were followed by the outcome made the target cue a conditioned inhibitor, passing both, retardation (Experiment 1a) and summation (Experiment 1b) tests of conditioned inhibition. Subsequent extinction of a different cue facilitated reversing the relationship between the conditioned inhibitor and the outcome regardless of whether the situation could be solved by using simple rules (Experiment 2) or not (Experiment 3). Results are discussed in terms of attentional theories that suggest extinction produces a nonspecific increase in attention that facilitates learning.

Ocular signatures of proactive versus reactive cognitive control in young adults.

During the execution of a cognitive task, the brain maintains contextual information to guide behavior and achieve desired goals. The AX-Continuous Performance Task is used to study proactive versus reactive cognitive control. Young adults tend to behave proactively in standard testing conditions. However, it remains unclear how interindividual variability (e.g., in cognitive and motivational factors) may drive people into more reactive or proactive control under the same task demands. We investigated the use of control strategies in a large population of healthy young adults. We computed the proactive behavioral index and consequently divided participants into proactive, reactive, and intermediate groups. We found that reactive participants were generally slower, presented lower context sensitivity, and larger response variability. Pupillary changes and blink rate index cognitive effort allocation. We measured, concomitantly to the task, the pupil size and frequency of blinks associated with the cue maintenance and response intervals. During the cue period, nonfrequent, nontarget cues led to increased pupil dilation and number of blinks in all participants. During the response interval, we found more errors and increased pupil dilation to the probe when all participants had to overcome a response bias generated by the frequent cue. Only reactive participants showed larger response-related pupil when they had to overcome a response bias related to the frequent probe. Contrary to expectations, groups did not differ in ocular measures in the cue period. In conclusion, interindividual differences in cognitive control between healthy adults can be mapped onto different patterns of effort allocation indexed by the pupil.

Fitness and ERP Indices of Cognitive Control Mode during Task Preparation in Preadolescent Children.

A growing number of studies conducted over the past decade have demonstrated that greater aerobic fitness is associated with superior cognitive control in preadolescent children. Several studies have suggested that the relationship between fitness and cognitive control may be attributed to differential reliance on proactive vs. reactive cognitive control modes. However, this contention has remained speculative, and further studies are needed to better elucidate this relationship. We designed the present study to test the hypothesis that use of cognitive control modes would differ as a function of childhood fitness. We compared performance of lower-fit and higher-fit children on a modified AX-continuous performance task, commonly used to examine shifts in the use of proactive and reactive control, along with cue-P3 and contingent negative variation (CNV) of event-related brain potentials (ERPs). Results indicated that higher-fit children exhibited greater response accuracy for BX (non-target cue – target probe) relative to AY (target cue – non-target probe) trials, whereas lower-fit children had comparable response accuracies for AY and BX trials. Because enhanced BX performance and impaired AY performance may be attributed to the proactive use of context information, these results suggest that greater childhood fitness is associated with more effective utilization of proactive control. Higher-fit children also exhibited larger cue-P3 amplitude and smaller CNV amplitude for BX relative to AY trials, with no such effect of trial type in lower-fit children. These ERP results suggest that greater fitness is associated with more effective utilization of cue information and response preparation more appropriate to trial type, supporting the behavioral findings. The present study provides novel insights into the relationship between fitness and cognition from the perspective of cognitive control mode during task preparation.

The relevance of the irrelevant: Attention and task-set adaptation in prematurely born adults.

To investigate attention and task-set adaptation in a preterm born very low birth weight (PT/VLBW) population by means of event-related potential components from an adapted cued go/no-go task. P3 components after target and non-target cues, as well as target, no-go and non-target imperative stimuli were compared in 30 PT/VLBW young adults and 33 term-born controls. Changes in P3 amplitudes as a function of time-on-task were also investigated. The PT/VLBW group had larger P3 amplitudes to non-target cues and non-targets compared with controls. There were no significant group differences in the P3s to target or no-go stimuli. Moreover, the amplitude of the P3 to non-target cues and non-targets decreased significantly over time in the control group but not in the PT/VLBW group. PT/VLBW young adults allocate more attention to behaviorally irrelevant information than term-born controls, and persist in attending to this information over time. This is the first study to investigate ERP components in an adult population born preterm with very low birth weight.

Enhancement and reduction of associative retroactive cue interference by training in multiple contexts.

Retroactive cue interference refers to situations in which a target cue X is paired with an outcome in phase 1 and a nontarget cue Z is paired with the same outcome in phase 2, with less subsequent responding to X being seen as a result of the phase 2 training. Two conditioned suppression experiments with rats were conducted to determine whether retroactive cue interference is similarly modulated by a manipulation that influences retroactive outcome interference (e.g., extinction). Both experiments used an ABC renewal-like design in which phase 1 training, phase 2 training, and testing each occurred in different contexts. Experiment 1 found that training the target association in multiple contexts without altering the number of training trials during phase 1 decreased retroactive cue interference (i.e., increased responding consistent with the target association). Experiment 2 found that training the interfering association in multiple contexts without altering the number of interference trials during phase 2 increased retroactive cue interference (i.e., decreased responding consistent with the target association). The possibility of similar mechanisms underlying cue interference and outcome interference is discussed.

The relationship between attentional capture and deviations in movement trajectories in a selective reaching task

According to action-centered models of attention, attention and action systems are tightly linked such that the capture of attention by an object automatically initiates response-producing processes. In support of this link, studies have shown that movements deviate towards or away from non-target stimuli. These deviations are thought to emerge because attentional capture by non-target stimuli generates responses that summate with target responses to develop a combined movement vector. The present study tested attention–action coupling by examining movement trajectories in the presence of non-target stimuli that do or do not capture attention. Previous research has revealed that non-target cue stimuli only capture attention when they share critical features with the target. Cues that do not share this feature do not capture attention. Following these studies and their findings, participants in the present study aimed to the location of a single white square (onset singleton target) or a single red square presented with two white squares (color singleton target). In separate blocks, targets were preceded by non-predictive cues that did or did not share the target feature (color or onset singleton cues). The critical finding of the present study was that trajectory effects mirrored the temporal interference effects in that deviations were only observed when cue and target properties matched. Deviations were not observed when the cue and target properties did not match. These data provide clear support for the link between attentional capture and the activation of response-producing processes.

Degraded contingency revisited: Posttraining extinction of a cover stimulus attenuates a target cue's behavioral control.

In a Pavlovian conditioning situation, unsignaled outcome presentations interspersed among cue-outcome pairings attenuate conditioned responding to the cue (i.e., the degraded contingency effect). However, if a nontarget cue signals these added outcomes, responding to the target cue is partially restored (i.e., the cover stimulus effect). In 2 conditioned suppression experiments using rats, the effect of posttraining extinction of the cover stimulus was examined. Experiment 1 found that this treatment yielded reduced responding to the target cue. Experiment 2 replicated this finding, while demonstrating that this basic effect was not due to acquired equivalence between the target cue and the cover stimulus. These results are consistent with the extended comparator hypothesis interpretation of the degraded contingency and cover stimulus effects.

Neuromodulation and Cognitive Performance: Recent Studies of Noradrenergic Locus Ceruleus Neurons in Behaving Monkeys

Locus ceruleus (LC) neurons are phasically activated at short latencies selectively by target stimuli but not by other task events. This response is easily shifted to the new target cue after reversal training, confirming that these responses are driven by stimulus meaning. Optimal performance has been associated with an intermediate level of tonic LC discharge. In addition, phasic responses to target stimuli occur only during epochs of excellent task performance associated with intermediate tonic LC activity. A computational model of the LC explains the relationship between patterns of LC firing and task performance by changes in electrotonic coupling among LC neurons. Specifically, it demonstrates that an increase in coupling results in greater phasic responses to target but not nontarget cues and also produces lower spontaneous (tonic) activity. This model can predict possibility of modulated electrotonic coupling among LC neurons to be an important factor that regulates LC activity and its role in behavioral performance. This chapter describes recording of such LC neurons in monkeys during performance of a visual discrimination task. This task required animals to stably foveate a central fixation spot on a video monitor.

Locus coeruleus neurons in monkey are selectively activated by attended cues in a vigilance task

Impulse activity was recorded extracellularly from noradrenergic neurons in the nucleus locus coeruleus (LC; 47 single-cell and 126 multicell recordings) of four cynomolgus monkeys performing an oddball visual discrimination task. For juice reward, the subjects were required to release a lever rapidly in response to an infrequent (10-20% of trials) target cue (CS+) that was randomly intermixed with nontarget (CS-) stimuli presented on a video display. All LC neurons examined were phasically and selectively activated by target cues in this task. Other task events elicited no consistent response from these neurons (juice reward, lever release, fix-spot stimuli, nontarget stimuli). In one animal, nontarget cues phasically inhibited LC neurons. Phasic LC excitatory responses to target cues in this task occurred at a relatively short latency (mean = 90.7 msec), approximately 200 msec prior to the behavioral response (lever release). In addition, LC response magnitudes varied with behavioral performance, being substantially attenuated during epochs of poor performance (high false alarm rate). There was a positive correlation (r = 0.30, p < 0.0001) between the latency of LC responses and the latency of behavioral responses to same target cues, consistent with the possibility that LC responses may have a role in selective attention by facilitating responses to the CS+ stimulus. Analyses of behavioral response latencies to pairs of stimuli indicated that LC responses may facilitate behavioral responses to subsequent sensory cues, consistent with a role of this system in sustained attention/vigilance. Moreover, responses became reduced in magnitude over time during prolonged task performance (> 90 min), in parallel with a behavioral performance decrement. These results show that LC neurons are activated selectively by attended stimuli that demand a rapid response in this task, and that such LC responses may contribute to conditioned behavioral responses.

Influence of multipole test sessions on perceptual weight of voicing cues

Previous research [T. R. Sawallis, ICSLP 92 Proc. 2, 1067–1073 (1992)] has shown the feasibility of using techniques from signal detection theory to quantify perceptual weights of acoustic cues. Their abstract nature makes these weights autonomous and generalizable across cues and conditions, unlike trading relations which use proportions to bind physical scales. These weights are also environmentally valid because the experimental design avoids multiply-edited ‘‘prototypes’’ in favor of multiple singly edited natural tokens. This preserves the behavior of the nontarget cues against which the experimental cues are balanced. Using the French intervocalic /t-d/ contrast, this measure has been shown to be influenced by the listener’s linguistic background (both native language and linguistic training) [T. R. Sawallis, J. Acoust. Soc. Am. 93, 2390(A) (1993)]. However, these results reflected only the subjects’ first sitting of the perceptual test. This paper reports the influence of multiple sittings of the test on both accuracy (i.e., error rates for edited and unedited tokens) and perceptual weight (i.e., sensitivity to the edited cue).

Perceptual weight of acoustic cues for voicing in French [t, d]: Population differences

An experiment is presented concerning perception of edited consonant length, voicing amplitude, and burst+aspiration amplitude in a corpus of natural tokens of French intervocalic [t, d]. The editing is designed using the statistical distributions of those cues as previously measured in the selfsame corpus. This design largely preserves the natural variation of the nontarget cues, and is an advantage over the traditional use of synthesis or prototype based series. Then, mathematical tools borrowed from signal detection theory are used on the perceptual test results to derive sensitivity measurements for the cues. Measurements of this type can be compared autonomously, without trading-relationship-style equivalences, across cues, environments, languages, etc., and this property makes them amenable to use not only in speech perception, but also in formal phonology and general linguistics. In this paper, they are used to explore differential use of cues of listener groups based on native language (French versus other native languages) and on linguistic training (‘‘naives’’ versus phoneticians, linguists, language teachers, etc.).

Local time horizons in Pavlovian learning.

Responding to a conditioned stimulus (CS) is impaired if the CS is trained in the presence of excitatory local context cues. Four lick suppression experiments with rats explored whether this local context effect arises from the influence of excitatory cues that precede or that follow a reinforced target CS. Pretrained nontarget stimuli served as local context cues that occurred (a) immediately before and after the target CS trial, (b) immediately before or after the target CS trial, or (c) only before or after the target CS trial with varying intervals between the nontarget stimulus and target CS. Results indicated similar control over responding to the target CS by the preceding and following nontarget cues. This outcome implies a symmetrical window of memory integration (local time horizon) for a Pavlovian CS. Possible mechanisms underlying the detrimental effect of embedding a CS in an excitatory local context are discussed.