Selective Attention Processes Research Articles

Visual Complexity and Affect: Ratings Reflect More Than Meets the Eye.

Pictorial stimuli can vary on many dimensions, several aspects of which are captured by the term ‘visual complexity.’ Visual complexity can be described as, “a picture of a few objects, colors, or structures would be less complex than a very colorful picture of many objects that is composed of several components.” Prior studies have reported a relationship between affect and visual complexity, where complex pictures are rated as more pleasant and arousing. However, a relationship in the opposite direction, an effect of affect on visual complexity, is also possible; emotional arousal and valence are known to influence selective attention and visual processing. In a series of experiments, we found that ratings of visual complexity correlated with affective ratings, and independently also with computational measures of visual complexity. These computational measures did not correlate with affect, suggesting that complexity ratings are separately related to distinct factors. We investigated the relationship between affect and ratings of visual complexity, finding an ‘arousal-complexity bias’ to be a robust phenomenon. Moreover, we found this bias could be attenuated when explicitly indicated but did not correlate with inter-individual difference measures of affective processing, and was largely unrelated to cognitive and eyetracking measures. Taken together, the arousal-complexity bias seems to be caused by a relationship between arousal and visual processing as it has been described for the greater vividness of arousing pictures. The described arousal-complexity bias is also of relevance from an experimental perspective because visual complexity is often considered a variable to control for when using pictorial stimuli.

Spatial Integration and the Underlying Mechanisms of Cross-Modality Interference.

Researchers have often utilized the classic Stroop task as a measure of selective attention processes. While it is largely agreed upon that semantic interference plays a role in the classic task, the role of attentional processes is less clear. The picture is further muddied when variations on the classic task are used. For example, the cross-modal Stroop task, in which one names the color of visual items while ignoring distracting auditory color words, typically leads to smaller sized interference effects and little or no facilitation when compared to the classic task. Furthermore, relationship(s) with working memory capacity have only been found in the classic version. We examined whether these differences are due to a methodological factor; namely, spatial integration versus separation of the target and distractor locations. We conducted four experiments manipulating the location of auditory distractors within the cross-modal Stroop task, and found that the location of the distractors had little to no impact on the size of the effect. This lack of an effect of location implies that the mechanisms contributing to the cross-modal Stroop effect are not the same as those of the classic Stroop effect, and that the role of spatial attention in cross-modal Stroop is limited. The implications of a unique role for auditory distractors is considered as well, and supports the conclusion that interference in the cross-modal Stroop effect is the result of a combination of semantic interference and modality-specific interference.

Recurrent Activation of Neural Circuits during Attention to Global and Local Visual Information.

The attentional selection of different hierarchical level within compound (Navon) figures has been studied with event related potentials (ERPs), by controlling the ERPs obtained during attention to the global or the local echelon. These studies, using the canonical Navon figures, have produced contradictory results, with doubts regarding the scalp distribution of the effects. Moreover, the evidence about the temporal evolution of the processing of these two levels is not clear. Here, we unveiled global and local letters at distinct times, which enabled separation of their ERP responses. We combine this approach with the temporal generalization methodology, a novel multivariate technique which facilitates exploring the temporal structure of these ERPs. Opposite lateralization patterns were obtained for the selection negativities generated when attending global and local distracters (D statistics, p < .005), with maxima in right and left occipito-temporal scalp regions, respectively (η2 = .111, p < .01; η2 = .042, p < .04). However, both discrimination negativities elicited when comparing targets and distractors at the global or the local level were lateralized to the left hemisphere (η2 = .25, p < .03 and η2 = .142, p < .05 respectively). Recurrent activation patterns were found for both global and local stimuli, with scalp topographies corresponding to early preparatory stages reemerging during the attentional selection process, thus indicating recursive attentional activation. This implies that selective attention to global and local hierarchical levels recycles similar neural correlates at different time points. These neural correlates appear to be mediated by visual extra-striate areas.

The speed of voluntary and priority-driven shifts of visual attention.

The question how fast spatial attention moves between different visual objects remains debated. We used electrophysiological measures to determine the speed of voluntary and visually guided shifts of attention. Participants shifted attention from a known benchmark object (T1) to a benchmark-defined target object (T2) in tasks where these shifts had to be controlled endogenously and tasks where they could be guided by visible stimulus attributes (target features or arrow cues). To track the speed of these attention shifts, we measured event-related potential (ERP) markers of attentional object selection (N2pc components). The N2pc to T1 emerged earlier than the N2pc to T2, confirming the presence of serial attention shifts. N2pc onset differences between T1 and T2 revealed that shifts guided by target features were triggered within 50 ms, whereas voluntary movements of attention took substantially longer (150 ms). Attention shifts signaled by arrow cues were initiated within about 100 ms. Results show that genuinely voluntary shifts of attention are slower than shifts that are guided by cues or target features, but can still be initiated more rapidly than has previously been assumed. They also demonstrate that EEG markers can track different types of serial attentional selection processes with high temporal precision. (PsycINFO Database Record

Pokazatelji dinamike funkcioniranja selektivne pažnje hrvatskih strojovođa i njihove dobne razlike

SUMMARY: Research that focuses on aging process of selective attention (SA) functioning dynamics is very rare, especially regarding the professional drivers’ population. Given the fact that the consequences of SA functioning in railroad engineers are extremely high for traffic safety, we considered it important to investigate the aging effects on three indicators of SA system functioning dynamics (average efficiency, stability and resilience to the adverse factors effects) with regard to different measures of SA. The study was conducted using two time limited forms of Stroop tests: the first – verbal, uncoloured (lexical) and the second – verbal, coloured paper-pencil form. Both forms were comprised of two parts/components: with incongruent stimuli (measuring SA and processing speed, i.e. PS) and neutral stimuli (measuring only PS). The participants were male railroad engineers, ages 25 to 59, unevenly distributed into 4 age categories distinguished by specific functional characteristics of professional drivers. 50 subjects completed the first test form and 52 the second. The subjects’ task was to cross out as many of the target words in the distractors context in 60 seconds as possible (whereby the distraction was more intense for the incongruent stimuli). All three indicators of SA functioning dynamics are expressed as composites of objective measures of the Stroop test components. They show an unambiguous relation to the magnitude of the associated construct, while low inter-correlations indicate their diversity. With the exception of the relative position of the first test mistake - that could not be used as a measure of resilience due to the extremely small variability - in the selected sample of Croatian railroad engineers most of the other SA dynamic indicators show good statistical features and theoretical merits. Age related changes of the three SA dynamic indicators reflect a non-linear trend that is only partly in line with the expectations, while statistically significant only for SA resilience in the coloured version of the Stroop test. Although these age-related trends were mainly non-significant, average SA efficiency and stability in the coloured version of the test showed significantly different age-related changes in comparison to the lexical version of the test. Additionally, analyses have shown that the average SA efficiency is significantly higher in Stroop test that includes traffic relevant colours, while SA stability and resilience to the adverse factors effects show similar, although not significant, trend. The findings are – with a certain caution related to the lack of control group measurement and other methodological confinements specific for applied research - interpreted by specific railroad engineers experience and are discussed in relation to the theory of cognitive aging in the general population with the implications on the railroad engineers aging process and its consequences – especially regarding traffic safety.

Difference in Perseverative Errors during a Visual Attention Task with Auditory Distractors in Alpha-9 Nicotinic Receptor Subunit Wild Type and Knock-Out Mice.

The auditory efferent system is a neural network that originates in the auditory cortex and projects to the cochlear receptor through olivocochlear (OC) neurons. Medial OC neurons make cholinergic synapses with outer hair cells (OHCs) through nicotinic receptors constituted by α9 and α10 subunits. One of the physiological functions of the α9 nicotinic receptor subunit (α9-nAChR) is the suppression of auditory distractors during selective attention to visual stimuli. In a recent study we demonstrated that the behavioral performance of alpha-9 nicotinic receptor knock-out (KO) mice is altered during selective attention to visual stimuli with auditory distractors since they made less correct responses and more omissions than wild type (WT) mice. As the inhibition of the behavioral responses to irrelevant stimuli is an important mechanism of the selective attention processes, behavioral errors are relevant measures that can reflect altered inhibitory control. Errors produced during a cued attention task can be classified as premature, target and perseverative errors. Perseverative responses can be considered as an inability to inhibit the repetition of an action already planned, while premature responses can be considered as an index of the ability to wait or retain an action. Here, we studied premature, target and perseverative errors during a visual attention task with auditory distractors in WT and KO mice. We found that α9-KO mice make fewer perseverative errors with longer latencies than WT mice in the presence of auditory distractors. In addition, although we found no significant difference in the number of target error between genotypes, KO mice made more short-latency target errors than WT mice during the presentation of auditory distractors. The fewer perseverative error made by α9-KO mice could be explained by a reduced motivation for reward and an increased impulsivity during decision making with auditory distraction in KO mice.

Neural activation patterns and connectivity in visual attention during Number and Non-number processing: An ERP study using the Ishihara pseudoisochromatic plates.

Visual cognitive function is important to build up executive function in daily life. Perception of visual Number form (e.g., Arabic digit) and numerosity (magnitude of the Number) is of interest to cognitive neuroscientists. Neural correlates and the functional measurement of Number representations are complex occurrences when their semantic categories are assimilated with other concepts of shape and colour. Colour perception can be processed further to modulate visual cognition. The Ishihara pseudoisochromatic plates are one of the best and most common screening tools for basic red-green colour vision testing. However, there is a lack of study of visual cognitive function assessment using these pseudoisochromatic plates. We recruited 25 healthy normal trichromat volunteers and extended these studies using a 128-sensor net to record event-related EEG. Subjects were asked to respond by pressing Numbered buttons when they saw the Number and Non-number plates of the Ishihara colour vision test. Amplitudes and latencies of N100 and P300 event related potential (ERP) components were analysed from 19 electrode sites in the international 10-20 system. Abrain topographic map, cortical activation patterns and Granger causation (effective connectivity) were analysed from 128 electrode sites. No major significant differences between N100 ERP components in either stimulus indicate early selective attention processing was similar for Number and Non-number plate stimuli, but Non-number plate stimuli evoked significantly higher amplitudes, longer latencies of the P300 ERP component with a slower reaction time compared to Number plate stimuli imply the allocation of attentional load was more in Non-number plate processing. Adifferent pattern of asymmetric scalp voltage map was noticed for P300 components with a higher intensity in the left hemisphere for Number plate tasks and higher intensity in the right hemisphere for Non-number plate tasks. Asymmetric cortical activation and connectivity patterns revealed that Number recognition occurred in the occipital and left frontal areas where as the consequence was limited to the occipital area during the Non-number plate processing. Finally, the results displayed that the visual recognition of Numbers dissociates from the recognition of Non-numbers at the level of defined neural networks. Number recognition was not only a process of visual perception and attention, but it was also related to a higher level of cognitive function, that of language.

Specific neurophysiological mechanisms underlie cognitive inflexibility in inflammatory bowel disease

Inflammatory bowel disease (IBD) is highly prevalent. While the pathophysiological mechanisms of IBD are increasingly understood, there is a lack of knowledge concerning cognitive dysfunctions in IBD. This is all the more the case concerning the underlying neurophysiological mechanisms. In the current study we focus on possible dysfunctions of cognitive flexibility (task switching) processes in IBD patients using a system neurophysiological approach combining event-related potential (ERP) recordings with source localization analyses. We show that there are task switching deficits (i.e. increased switch costs) in IBD patients. The neurophysiological data show that even though the pathophysiology of IBD is diverse and wide-spread, only specific cognitive subprocesses are altered: There was a selective dysfunction at the response selection level (N2 ERP) associated with functional alterations in the anterior cingulate cortex and the right inferior frontal gyrus. Attentional selection processes (N1 ERP), perceptual categorization processes (P1 ERP), or mechanisms related to the flexible implementation of task sets and related working memory processes (P3 ERP) do not contribute to cognitive inflexibility in IBD patients and were unchanged. It seems that pathophysiological processes in IBD strongly compromise cognitive-neurophysiological subprocesses related to fronto-striatal networks. These circuits may become overstrained in IBD when cognitive flexibility is required.

Target objects defined by a conjunction of colour and shape can be selected independently and in parallel.

It is generally assumed that during search for targets defined by a feature conjunction, attention is allocated sequentially to individual objects. We tested this hypothesis by tracking the time course of attentional processing biases with the N2pc component in tasks where observers searched for two targets defined by a colour/shape conjunction. In Experiment 1, two displays presented in rapid succession (100 ms or 10 ms SOA) each contained a target and a colour-matching or shape-matching distractor on opposite sides. Target objects in both displays elicited N2pc components of similar size that overlapped in time when the SOA was 10 ms, suggesting that attention was allocated in parallel to both targets. Analogous results were found in Experiment 2, where targets and partially matching distractors were both accompanied by an object without target-matching features. Colour-matching and shape-matching distractors also elicited N2pc components, and the target N2pc was initially identical to the sum of the two distractor N2pcs, suggesting that the initial phase of attentional object selection was guided independently by feature templates for target colour and shape. Beyond 230 ms after display onset, the target N2pc became superadditive, indicating that attentional selection processes now started to be sensitive to the presence of feature conjunctions. Results show that independent attentional selection processes can be activated in parallel by two target objects in situations where these objects are defined by a feature conjunction.

Habituation as an adaptive shift in response strategy mediated by neuropeptides

Habituation is a non-associative form of learning characterized by a decremented response to repeated stimulation. It is typically framed as a process of selective attention, allowing animals to ignore irrelevant stimuli in order to free up limited cognitive resources. However, habituation can also occur to threatening and toxic stimuli, suggesting that habituation may serve other functions. Here we took advantage of a high-throughput Caenorhabditis elegans learning assay to investigate habituation to noxious stimuli. Using real-time computer vision software for automated behavioral tracking and optogenetics for controlled activation of a polymodal nociceptor, ASH, we found that neuropeptides mediated habituation and performed an RNAi screen to identify candidate receptors. Through subsequent mutant analysis and cell-type-specific gene expression, we found that pigment-dispersing factor (PDF) neuropeptides function redundantly to promote habituation via PDFR-1-mediated cAMP signaling in both neurons and muscles. Behavioral analysis during learning acquisition suggests that response habituation and sensitization of locomotion are parts of a shifting behavioral strategy orchestrated by pigment dispersing factor signaling to promote dispersal away from repeated aversive stimuli.

Individual Differences in the Accuracy of Judgments of Learning Are Related to the Gray Matter Volume and Functional Connectivity of the Left Mid-Insula.

The judgment of learning (JOL) is an important form of prospective metamemory judgment, and the biological basis of the JOL process is an important topic in metamemory research. Although previous task-related functional magnetic resonance imaging (MRI) studies have examined the brain regions underlying the JOL process, the neural correlates of individual differences in JOL accuracy require further investigation. This study used structural and resting-state functional MRI to investigate whether individual differences in JOL accuracy are related to the gray matter (GM) volume and functional connectivity of the bilateral insula and medial Brodmann area (BA) 11, which are assumed to be related to JOL accuracy. We found that individual differences in JOL accuracy were related to the GM volume of the left mid-insula and to the functional connectivity between the left mid-insula and various other regions, including the left superior parietal lobule/precuneus, bilateral inferior parietal lobule/intraparietal sulcus, right frontal pole and left parahippocampal gyrus/fusiform gyrus/cerebellum. Further analyses indicated that the functional connectivity related to individual differences in JOL accuracy could be divided into two factors and might support information integration and selective attention processes underlying accurate JOLs. In addition, individual differences in JOL accuracy were not related to the GM volume or functional connectivity of the medial BA 11. Our findings provide novel evidence for the role of the left mid-insula and its functional connectivity in the JOL process.

A Comparison of Selective Attention Processing in Major Depressive Disorder and Schizophrenia

A Comparison of Selective Attention Processing in Major Depressive Disorder and Schizophrenia

Neural signals of selective attention are modulated by subjective preferences and buying decisions in a virtual shopping task

We investigated whether well-known neural markers of selective attention to motivationally-relevant stimuli were modulated by variations in subjective preference towards consumer goods in a virtual shopping task. Specifically, participants viewed and rated pictures of various goods on the extent to which they wanted each item, which they could potentially purchase afterwards. Using the event-related potentials (ERP) method, we found that variations in subjective preferences for consumer goods strongly modulated positive slow waves (PSW) from 800 to 3000 milliseconds after stimulus onset. We also found that subjective preferences modulated the N200 and the late positive potential (LPP). In addition, we found that both PSW and LPP were modulated by subsequent buying decisions. Overall, these findings show that well-known brain event-related potentials reflecting selective attention processes can reliably index preferences to consumer goods in a shopping environment. Based on a large body of previous research, we suggest that early ERPs (e.g. the N200) to consumer goods could be indicative of preferences driven by unconditional and automatic processes, whereas later ERPs such as the LPP and the PSW could reflect preferences built upon more elaborative and conscious cognitive processes.

Ignorance reflects preference: the influence of selective ignoring on evaluative conditioning

ABSTRACTIn the current experiment, we investigated the mechanism underlying the modulation of evaluative conditioning (EC) due to selective attention. Conditioned stimulus–unconditioned stimulus (CS–US) pairs were presented in a just recently introduced adapted Flanker paradigm [Blask, K., Walther, E., & Frings, C. (2016). When congruence breeds preference: The influence of selective attention processes on evaluative conditioning. Cognition and Emotion. doi:10.1080/02699931.2016.1197100] with CSs as targets and USs as task-irrelevant distracters. In order to disentangle stimulus congruency and response compatibility and in order to observe a possible impact of response compatibility, EC in an incongruent/incompatible condition was compared to EC in an incongruent/neutral condition. Results show that EC and contingency memorywere significantly reduced in the incongruent/incompatible condition relative to the incongruent/neutral condition. These findings support the notion that the modulation of EC due to selective attention can be based on the selective ignoring of the US at the level of response compatibility.

Theta- and delta-band EEG network dynamics during a novelty oddball task.

While the P3 component during target detection and novelty processing has been widely studied, less is known about its underlying network dynamics. A recent cognitive model suggests that frontal-parietal and frontal-temporal interregional connectivity are related to attention/action selection and target-related memory updating during the P3, respectively, but empirical work testing this model is lacking. Other work suggests the importance of theta- and delta-band connectivity between the medial frontal cortex and distributed cortical regions during attention, stimulus detection, and response selection processes, and similar dynamics may underlie P3-related network connectivity. The present study evaluated the functional connectivity elicited during a visual task, which combined oddball target and novelty stimuli, in a sample of 231 same-sex twins. It was hypothesized that both target and novel conditions would involve theta frontoparietal connectivity and medial frontal theta power, but that target stimuli would elicit the strongest frontotemporal connectivity. EEG time-frequency analysis revealed greater theta-band frontoparietal connectivity and medial frontal power during both target and novel conditions compared to standards, which may index conflict/uncertainty resolution processes. Theta-band frontotemporal connectivity was maximal during the target condition, potentially reflecting context updating or stimulus-response activation. Delta-band frontocentral-parietal connectivity was also strongest following targets, which may be sensitive to response-related demands. These results suggest the existence of functional networks related to P3 that are differentially engaged by target oddballs and novel distractors. Compared to simple P3 amplitude, network measures may provide a more nuanced view of the neural dynamics during target detection/novelty processing in normative and pathological populations.

The mediating role of rumination in the relation between attentional bias towards thin female bodies and eating disorder symptomatology.

The present study sought to investigate the association between selective attentional processing of body images, rumination, and eating disorder symptoms in young women. Seventy-three undergraduate female students (ages 17–24) completed a modified dot-probe task to assess whether young women showed a differential attentional bias pattern towards thin and non-thin female bodies. Participants also completed self-report measures of eating disorder pathology. It was found that increased reports of dietary restraint and body dissatisfaction were associated with both greater attentional bias towards thin bodies and avoidance of non-thin bodies (as compared to neutral images), although the former relationship was stronger than the latter. The results suggest attentional vigilance to thin-ideal images plays a greater role in the potential development and/or maintenance of eating disorder symptoms, at least in a university sample of young women. Results also revealed that eating disorder-specific rumination mediated the relationship between attentional bias to thin ideal images and eating disorder symptoms. These findings build on existing research and theories, for example the impaired disengagement model of rumination, and have potential clinical applications such as specifically targeting ruminative and/or attentional processes in the prevention and/or treatment of eating disorder symptoms.

The Basal Ganglia Striosomes Affect the Modulation of Conflicts by Subliminal Information—Evidence from X-Linked Dystonia Parkinsonism

Cognitive control is relevant when distracting information induces behavioral conflicts. Such conflicts can be produced consciously and by subliminally processed information. Interestingly, both sources of conflict interact suggesting that they share neural mechanisms. Here, we ask whether conjoint effects between different sources of conflict are modulated by microstructural basal ganglia dysfunction. To this end, we carried out an electroencephalography study and examined event-related potentials (ERPs) including source localization using a combined flanker-subliminal priming task in patients with X-linked dystonia Parkinsonism (XDP) and a group of healthy controls. XDP in its early stages is known to predominantly affect the basal ganglia striosomes. The results suggest that conjoint effects between subliminal and conscious sources of conflicts are modulated by the striosomes and were stronger in XDP patients. The neurophysiological data indicate that this effect is related to modulations in conflict monitoring and response selection (N2 ERP) mechanisms engaging the anterior cingulate cortex. Bottom-up perceptual gating, attentional selection, and motor response activation processes in response to the stimuli (P1, N1, and lateralized readiness potential ERPs) were unaffected. Taken together, these data indicate that striosomes modulate the processing of conscious and subliminal sources of conflict suggesting that microstructural basal ganglia properties are relevant for cognitive control.

Spatiotemporal oscillatory dynamics of visual selective attention during a flanker task

The flanker task is a test of visual selective attention that has been widely used to probe error monitoring, response conflict, and related constructs. However, to date, few studies have focused on the selective attention component of this task and imaged the underlying oscillatory dynamics serving task performance. In this study, 21 healthy adults successfully completed an arrow-based version of the Eriksen flanker task during magnetoencephalography (MEG). All MEG data were pre-processed and transformed into the time-frequency domain. Significant oscillatory brain responses were imaged using a beamforming approach, and voxel time series were extracted from the peak responses to identify the temporal dynamics. Across both congruent and incongruent flanker conditions, our results indicated robust decreases in alpha (9–12Hz) activity in medial and lateral occipital regions, bilateral parietal cortices, and cerebellar areas during task performance. In parallel, increases in theta (3–7Hz) oscillatory activity were detected in dorsal and ventral frontal regions, and the anterior cingulate. As per conditional effects, stronger alpha responses (i.e., greater desynchronization) were observed in parietal, occipital, and cerebellar cortices during incongruent relative to congruent trials, whereas the opposite pattern emerged for theta responses (i.e., synchronization) in the anterior cingulate, left dorsolateral prefrontal, and ventral prefrontal cortices. Interestingly, the peak latency of theta responses in these latter brain regions was significantly correlated with reaction time, and may partially explain the amplitude difference observed between congruent and incongruent trials. Lastly, whole-brain exploratory analyses implicated the frontal eye fields, right temporoparietal junction, and premotor cortices. These findings suggest that regions of both the dorsal and ventral attention networks contribute to visual selective attention processes during incongruent trials, and that such differential processes are transient and fully completed shortly after the behavioral response in most trials.

Response inhibition is more effortful than response activation: behavioral and electrophysiological evidence.

The present study aimed to measure the response inhibition by embedding a secondary probe task within a Go/NoGo paradigm. The response time for the probe and the time course of the discrimination process for the probe shown by event-related potentials were measured to investigate the effect of response inhibition. The results showed that the probe response time were longer for the NoGo-probes versus Go-probes, indicating a more cognitively demanding process in processing NoGo stimuli. The event-related potential results showed that the NoGo stimuli evoked a more positive frontal P3 component relative to the Go stimuli. Compared with the NoGo-probes, the Go-probes evoked enhanced N1, but decreased P2 and P3 components over frontocentral scalps, indicating increased orienting process, but decreased selective attention process for the Go-probes. These results indicated that response inhibition (NoGo) was more cognitively demanding than the response activation (Go).

Learning-related improvements in auditory detection sensitivities correlate with changes in sensory- and decision-related components of the event-related potential

Listener performance in an auditory detection task can improve with practice (Zwislocki, Maire, Feldman, &amp; Rubin, 1958). This could result from a selective attention process and/or sensory plasticity (e.g., if trained stimuli receive increased cortical representation). Here, listeners were trained to detect either an 861-Hz or 1058-Hz tone (counterbalanced across participants) presented in a noise masker. On the following day, high-density EEG was collected while listeners: 1) attempted to detect 861-Hz and 1058-Hz tones in noise at an SNR of -21 dB, and 2) passively heard the same tones presented in quiet. Listeners were significantly better at detecting tones at their trained frequency. In addition, P3 amplitudes were larger for trained than for untrained tones during the detection task. During passive exposure to the same tones, P2 amplitudes were similarly larger for trained than for untrained tones. The difference in P3 amplitudes suggests that training leads to more efficient decisional processing, perhaps related to an expectation for tones at the trained frequency. Differences in P2 amplitudes may reflect training-induced sensory cortical plasticity that is frequency specific. Further, the difference in P2 amplitudes suggests that training-induced improvements in detection are not merely related to attentional modulations.