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1.
Psychophysiology ; 61(7): e14557, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38459638

RESUMEN

When memorizing an integrated object such as a Kanizsa figure, the completion of parts into a coherent whole is attained by grouping processes which render a whole-object representation in visual working memory (VWM). The present study measured event-related potentials (ERPs) and oscillatory amplitudes to track these processes of encoding and representing multiple features of an object in VWM. To this end, a change detection task was performed, which required observers to memorize both the orientations and colors of six "pacman" items while inducing configurations of the pacmen that systematically varied in terms of their grouping strength. The results revealed an effect of object configuration in VWM despite physically constant visual input: change detection for both orientation and color features was more accurate with increased grouping strength. At the electrophysiological level, the lateralized ERPs and alpha activity mirrored this behavioral pattern. Perception of the orientation features gave rise to the encoding of a grouped object as reflected by the amplitudes of the Ppc. The grouped object structure, in turn, modulated attention to both orientation and color features as indicated by the enhanced N1pc and N2pc. Finally, during item retention, the representation of individual objects and the concurrent allocation of attention to these memorized objects were modulated by grouping, as reflected by variations in the CDA amplitude and a concurrent lateralized alpha suppression, respectively. These results indicate that memorizing multiple features of grouped, to-be-integrated objects involves multiple, sequential stages of processing, providing support for a hierarchical model of object representations in VWM.


Asunto(s)
Ritmo alfa , Electroencefalografía , Potenciales Evocados , Memoria a Corto Plazo , Humanos , Memoria a Corto Plazo/fisiología , Masculino , Femenino , Adulto Joven , Ritmo alfa/fisiología , Potenciales Evocados/fisiología , Adulto , Percepción Visual/fisiología , Atención/fisiología , Estimulación Luminosa , Reconocimiento Visual de Modelos/fisiología
2.
Int J Mol Sci ; 25(6)2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38542242

RESUMEN

Cardiovascular diseases are a significant cause of illness and death worldwide, often resulting in myofibroblast differentiation, pathological remodeling, and fibrosis, characterized by excessive extracellular matrix protein deposition. Treatment options for cardiac fibrosis that can effectively target myofibroblast activation and ECM deposition are limited, necessitating an unmet need for new therapeutic approaches. In recent years, microcurrent therapy has demonstrated promising therapeutic effects, showcasing its translational potential in cardiac care. This study therefore sought to investigate the effects of microcurrent therapy on cardiac myofibroblasts, aiming to unravel its potential as a treatment for cardiac fibrosis and heart failure. The experimental design involved the differentiation of primary rat cardiac fibroblasts into myofibroblasts. Subsequently, these cells were subjected to microcurrent (MC) treatment at 1 and 2 µA/cm2 DC with and without polarity reversal. We then investigated the impact of microcurrent treatment on myofibroblast cell behavior, including protein and gene expression, by performing various assays and analyses comparing them to untreated myofibroblasts and cardiac fibroblasts. The application of microcurrents resulted in distinct transcriptional signatures and improved cellular processes. Gene expression analysis showed alterations in myofibroblast markers, extracellular matrix components, and pro-inflammatory cytokines. These observations show signs of microcurrent-mediated reversal of myofibroblast phenotype, possibly reducing cardiac fibrosis, and providing insights for cardiac tissue repair.


Asunto(s)
Cardiomiopatías , Miofibroblastos , Ratas , Animales , Miofibroblastos/metabolismo , Miocardio/metabolismo , Fibroblastos/metabolismo , Corazón/fisiología , Cardiomiopatías/metabolismo , Diferenciación Celular , Fibrosis
3.
J Cogn Neurosci ; 35(4): 543-570, 2023 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-36735602

RESUMEN

Redundant combination of target features from separable dimensions can expedite visual search. The dimension-weighting account explains these "redundancy gains" by assuming that the attention-guiding priority map integrates the feature-contrast signals generated by targets within the respective dimensions. The present study investigated whether this hierarchical architecture is sufficient to explain the gains accruing from redundant targets defined by features in different modalities, or whether an additional level of modality-specific priority coding is necessary, as postulated by the modality-weighting account (MWA). To address this, we had observers perform a visuo-tactile search task in which targets popped out by a visual feature (color or shape) or a tactile feature (vibro-tactile frequency) as well as any combination of these features. The RT gains turned out larger for visuo-tactile versus visual redundant targets, as predicted by the MWA. In addition, we analyzed two lateralized event-related EEG components: the posterior (PCN) and central (CCN) contralateral negativities, which are associated with visual and tactile attentional selection, respectively. The CCN proved to be a stable somatosensory component, unaffected by cross-modal redundancies. In contrast, the PCN was sensitive to cross-modal redundancies, evidenced by earlier onsets and higher amplitudes, which could not be explained by linear superposition of the earlier CCN onto the later PCN. Moreover, linear mixed-effect modeling of the PCN amplitude and timing parameters accounted for approximately 25% of the behavioral RT variance. Together, these behavioral and PCN effects support the hierarchy of priority-signal computation assumed by the MWA.


Asunto(s)
Atención , Tacto , Humanos
4.
Psychol Sci ; 31(12): 1531-1543, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33119432

RESUMEN

Visual search is facilitated when the target is repeatedly encountered at a fixed position within an invariant (vs. randomly variable) distractor layout-that is, when the layout is learned and guides attention to the target, a phenomenon known as contextual cuing. Subsequently changing the target location within a learned layout abolishes contextual cuing, which is difficult to relearn. Here, we used lateralized event-related electroencephalogram (EEG) potentials to explore memory-based attentional guidance (N = 16). The results revealed reliable contextual cuing during initial learning and an associated EEG-amplitude increase for repeated layouts in attention-related components, starting with an early posterior negativity (N1pc, 80-180 ms). When the target was relocated to the opposite hemifield following learning, contextual cuing was effectively abolished, and the N1pc was reversed in polarity (indicative of persistent misguidance of attention to the original target location). Thus, once learned, repeated layouts trigger attentional-priority signals from memory that proactively interfere with contextual relearning after target relocation.


Asunto(s)
Señales (Psicología) , Aprendizaje , Humanos , Tiempo de Reacción , Percepción Visual
5.
J Vis ; 20(3): 5, 2020 03 17.
Artículo en Inglés | MEDLINE | ID: mdl-32196068

RESUMEN

Previous electroencephalographic research on attentional salience did not fully capture the complexities of low-level vision, which relies on both cone-opponent chromatic and cone-additive luminance mechanisms. We systematically varied color and luminance contrast using a visual search task for a higher contrast target to assess the degree to which the salience-computing attentional mechanisms are constrained by low-level visual inputs. In our first experiment, stimuli were defined by contrast that isolated chromatic or luminance mechanisms. In our second experiment, targets were defined by contrasts that isolated or combined achromatic and chromatic mechanisms. In both experiments, event-related potential waveforms contralateral and ipsilateral to the target were qualitatively different for chromatic- compared to luminance-defined stimuli. The same was true of the difference waves computed from these waveforms, with isoluminant stimuli eliciting a mid-latency posterior contralateral negativity (PCN) component and achromatic stimuli eliciting a complex of multiple components, including an early posterior contralateral positivity followed by a late-latency PCN. Combining color with luminance resulted in waveform and difference wave patterns equivalent to those of achromatic stimuli. When large levels of chromaticity contrast were added to targets with small levels of luminance contrast, PCN latency was speeded. In conclusion, the mechanisms underlying attentional salience are constrained by the low-level inputs they receive. Furthermore, speeded PCN latencies for stimuli that combine color and luminance signals compared to stimuli that contain luminance alone demonstrate that color and luminance channels are integrated during pre-attentive visual processing, before top-down allocation of attention is triggered.


Asunto(s)
Adaptación Ocular/fisiología , Percepción de Color/fisiología , Neuronas Retinianas/fisiología , Percepción Visual/fisiología , Adulto , Sensibilidad de Contraste/fisiología , Electroencefalografía , Potenciales Evocados/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estimulación Luminosa/métodos , Adulto Joven
6.
J Neurosci ; 37(9): 2504-2515, 2017 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-28137968

RESUMEN

One of the most firmly established factors determining the speed of human behavioral responses toward action-critical stimuli is the spatial correspondence between the stimulus and response locations. If both locations match, the time taken for response production is markedly reduced relative to when they mismatch, a phenomenon called the Simon effect. While there is a consensus that this stimulus-response (S-R) conflict is associated with brief (4-7 Hz) frontal midline theta (fmθ) complexes generated in medial frontal cortex, it remains controversial (1) whether there are multiple, simultaneously active theta generator areas in the medial frontal cortex that commonly give rise to conflict-related fmθ complexes; and if so, (2) whether they are all related to the resolution of conflicting task information. Here, we combined mental chronometry with high-density electroencephalographic measures during a Simon-type manual reaching task and used independent component analysis and time-frequency domain statistics on source-level activities to model fmθ sources. During target processing, our results revealed two independent fmθ generators simultaneously active in or near anterior cingulate cortex, only one of them reflecting the correspondence between current and previous S-R locations. However, this fmθ response is not exclusively linked to conflict but also to other, conflict-independent processes associated with response slowing. These results paint a detailed picture regarding the oscillatory correlates of conflict processing in Simon tasks, and challenge the prevalent notion that fmθ complexes induced by conflicting task information represent a unitary phenomenon related to cognitive control, which governs conflict processing across various types of response-override tasks.SIGNIFICANCE STATEMENT Humans constantly monitor their environment for and adjust their cognitive control settings in response to conflicts, an ability that arguably paves the way for survival in ever-changing situations. Anterior cingulate-generated frontal midline theta (fmθ) complexes have been hypothesized to play a role in this conflict-monitoring function. However, it remains a point of contention whether fmθ complexes govern conflict processing in a unitary, paradigm-nonspecific manner. Here, we identified two independent fmθ oscillations triggered during a Simon-type task, only one of them reflecting current and previous conflicts. Importantly, this signal differed in various respects (cortical origin, intertrial history) from fmθ phenomena in other response-override tasks, challenging the prevalent notion of conflict-induced fmθ as a unitary phenomenon associated with the resolution of conflict.


Asunto(s)
Adaptación Fisiológica/fisiología , Conflicto Psicológico , Lóbulo Frontal/fisiología , Desempeño Psicomotor/fisiología , Detección de Señal Psicológica/fisiología , Ritmo Teta/fisiología , Adulto , Mapeo Encefálico , Electroencefalografía , Femenino , Lóbulo Frontal/diagnóstico por imagen , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Estimulación Luminosa , Análisis de Componente Principal , Tiempo de Reacción/fisiología , Percepción Visual , Adulto Joven
7.
J Cogn Neurosci ; 30(4): 482-497, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29244636

RESUMEN

Selective attention controls the distribution of our visual system's limited processing resources to stimuli in the visual field. Two independent parameters of visual selection can be quantified by modeling an individual's performance in a partial-report task based on the computational theory of visual attention (TVA): (i) top-down control α, the relative attentional weighting of relevant over irrelevant stimuli, and (ii) spatial bias wλ, the relative attentional weighting of stimuli in the left versus right hemifield. In this study, we found that visual event-related electroencephalographic lateralizations marked interindividual differences in these two functions. First, individuals with better top-down control showed higher amplitudes of the posterior contralateral negativity than individuals with poorer top-down control. Second, differences in spatial bias were reflected in asymmetries in earlier visual event-related lateralizations depending on the hemifield position of targets; specifically, individuals showed a positivity contralateral to targets presented in their prioritized hemifield and a negativity contralateral to targets presented in their nonprioritized hemifield. Thus, our findings demonstrate that two functionally different aspects of attentional weighting quantified in the respective TVA parameters are reflected in two different neurophysiological measures: The observer-dependent spatial bias influences selection by a bottom-up processing advantage of stimuli appearing in the prioritized hemifield. By contrast, task-related target selection governed by top-down control involves active enhancement of target, and/or suppression of distractor, processing. These results confirm basic assumptions of the TVA framework, complement the functional interpretation of event-related lateralization components in selective attention studies, and are of relevance for the development of neurocognitive attentional assessment procedures.


Asunto(s)
Atención/fisiología , Encéfalo/fisiología , Lateralidad Funcional , Individualidad , Percepción Espacial/fisiología , Percepción Visual/fisiología , Adulto , Electroencefalografía , Potenciales Evocados , Femenino , Humanos , Masculino , Adulto Joven
8.
J Neurophysiol ; 119(1): 347-355, 2018 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-29070629

RESUMEN

Completion of a partially occluded object requires that a representation of the whole is constructed based on the information provided by the physically specified parts of the stimulus. Such processes of amodal completion rely on the generation and maintenance of a mental image that renders the completed object in visual working memory (VWM). The present study examined this relationship between VWM storage and processes of object completion. We recorded event-related potentials to track VWM maintenance by means of the contralateral delay activity (CDA) during a change detection task in which composite objects (notched shapes abutting an occluding shape) to be memorized were primed to induce either a globally completed object or a noncompleted, mosaic representation. The results revealed an effect of completion in VWM despite physically identical visual input: change detection was more accurate for completed compared with mosaic representations when observers were required to memorize two objects, and these differences were reduced with four memorized items. At the electrophysiological level, globally completed (vs. mosaic) objects gave rise to a corresponding increase in CDA amplitudes. These results indicate that although incorporating the occluded portions of the presented shapes requires mnemonic resources, the complete object representations thus formed in VWM improve change detection performance by providing a more simple, regular shape. Overall, these findings demonstrate that mechanisms of object completion modulate VWM, with the memory load being determined by the structured representations of the memorized stimuli. NEW & NOTEWORTHY This study shows that completion of partially occluded objects requires visual working memory (VWM) resources. In the experiment reported, we induced observers to memorize a given visual input either as completed or as noncompleted objects. The results revealed both a behavioral performance advantage for completed vs. noncompleted objects despite physically identical input, and an associated modulation of an electrophysiological component that reflects VWM object retention, thus indicating that constructing an integrated object consumes mnemonic resources.


Asunto(s)
Memoria a Corto Plazo , Reconocimiento Visual de Modelos , Adulto , Encéfalo/fisiología , Potenciales Evocados , Femenino , Humanos , Masculino , Tiempo de Reacción
9.
Cogn Affect Behav Neurosci ; 18(2): 296-312, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29442284

RESUMEN

The brain's reward system undergoes major changes during adolescence, and an increased reactivity to social and nonsocial incentives has been described as a typical feature during this transitional period. Little is known whether there are sex differences in the brain's responsiveness to social or monetary incentives during adolescence. The aim of this event-related potential (ERP) study was to compare the neurophysiological underpinnings of monetary and social incentive processing in adolescent boys versus girls. During ERP recording, 38 adolescents (21 females, 17 males; 13-18 years) completed an incentive delay task comprising (a) a reward versus punishment condition and (b) social versus monetary incentives. The stimulus-preceding negativity (SPN) was recorded during anticipation of reward and punishment, and the feedback P3 (fP3) along with the feedback-related negativity (FRN) after reward/punishment delivery. During anticipation of social punishment, adolescent boys compared with girls exhibited a reduced SPN. After delivery, male adolescents exhibited higher fP3 amplitudes to monetary compared with social incentives, whereas fP3 amplitudes in girls were comparable across incentive types. Moreover, whereas in boys fP3 responses were higher in rewards than in punishment trials, no such difference was evident in girls. The results indicate that adolescent boys show a reduced neural responsivity in the prospect of social punishment. Moreover, the findings imply that, once the incentive is obtained, adolescent boys attribute a relatively enhanced motivational significance to monetary incentives and show a relative hyposensitivity to punishment. The findings might contribute to our understanding of sex-specific vulnerabilities to problem behaviors related to incentive processing during adolescence.


Asunto(s)
Motivación , Caracteres Sexuales , Conducta Social , Adolescente , Señales (Psicología) , Electroencefalografía , Potenciales Evocados , Femenino , Humanos , Masculino , Castigo , Tiempo de Reacción , Recompensa
10.
Neuroimage ; 156: 166-173, 2017 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-28502842

RESUMEN

Sometimes, salient-but-irrelevant objects (distractors) presented concurrently with a search target cannot be ignored and attention is involuntarily allocated towards the distractor first. Several studies have provided electrophysiological evidence for involuntary misallocations of attention towards a distractor, but much less is known about the mechanisms that are needed to overcome a misallocation and re-allocate attention towards the concurrently presented target. In our study, electrophysiological markers of attentional mechanisms indicate that (i) the distractor captures attention before the target is attended, (ii) a misallocation of attention is terminated actively (instead of attention fading passively), and (iii) the misallocation of attention towards a distractor delays the attention allocation towards the target (rather than just delaying some post-attentive process involved in response selection). This provides the most complete demonstration, to date, of the chain of attentional mechanisms that are evoked when attention is misguided and recovers from capture within a search display.


Asunto(s)
Atención/fisiología , Encéfalo/fisiología , Percepción Visual/fisiología , Adulto , Electroencefalografía , Potenciales Evocados/fisiología , Femenino , Humanos , Masculino , Estimulación Luminosa , Adulto Joven
11.
Behav Brain Sci ; 40: e156, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-29342607

RESUMEN

We argue that although the framework put forward by Hulleman & Olivers (H&O) can successfully explain much of visual search behaviour, it appears limited to tasks without precise target identification demands. In particular, we contend that the unit of selection may be larger than a single item in standard detection tasks, whereas the unit may mandatorily be item-based in compound tasks.


Asunto(s)
Atención , Tiempo de Reacción , Electrofisiología
12.
Hum Brain Mapp ; 36(3): 935-44, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25351495

RESUMEN

It is well established that we can focally attend to a specific region in visual space without shifting our eyes, so as to extract action-relevant sensory information from covertly attended locations. The underlying mechanisms that determine how fast we engage our attentional spotlight in visual-search scenarios, however, remain controversial. One dominant view advocated by perceptual decision-making models holds that the times taken for focal-attentional selection are mediated by an internal template that biases perceptual coding and selection decisions exclusively through target-defining feature coding. This notion directly predicts that search times remain unaffected whether or not participants can anticipate the upcoming distractor context. Here we tested this hypothesis by employing an illusory-figure localization task that required participants to search for an invariant target amongst a variable distractor context, which gradually changed--either randomly or predictably--as a function of distractor-target similarity. We observed a graded decrease in internal focal-attentional selection times--correlated with external behavioral latencies--for distractor contexts of higher relative to lower similarity to the target. Critically, for low but not intermediate and high distractor-target similarity, these context-driven effects were cortically and behaviorally amplified when participants could reliably predict the type of distractors. This interactive pattern demonstrates that search guidance signals can integrate information about distractor, in addition to target, identities to optimize distractor-target competition for focal-attentional selection.


Asunto(s)
Atención/fisiología , Corteza Cerebral/fisiología , Conducta de Elección/fisiología , Reconocimiento Visual de Modelos/fisiología , Desempeño Psicomotor/fisiología , Adulto , Electroencefalografía , Femenino , Neuroimagen Funcional , Humanos , Masculino , Adulto Joven
13.
Cereb Cortex ; 24(8): 1967-78, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23535180

RESUMEN

An individual's visual attentional capacity is characterized by 2 central processing resources, visual perceptual processing speed and visual short-term memory (vSTM) storage capacity. Based on Bundesen's theory of visual attention (TVA), independent estimates of these parameters can be obtained from mathematical modeling of performance in a whole report task. The framework's neural interpretation (NTVA) further suggests distinct brain mechanisms underlying these 2 functions. Using an interindividual difference approach, the present study was designed to establish the respective ERP correlates of both parameters. Participants with higher compared to participants with lower processing speed were found to show significantly reduced visual N1 responses, indicative of higher efficiency in early visual processing. By contrast, for participants with higher relative to lower vSTM storage capacity, contralateral delay activity over visual areas was enhanced while overall nonlateralized delay activity was reduced, indicating that holding (the maximum number of) items in vSTM relies on topographically specific sustained activation within the visual system. Taken together, our findings show that the 2 main aspects of visual attentional capacity are reflected in separable neurophysiological markers, validating a central assumption of NTVA.


Asunto(s)
Atención/fisiología , Encéfalo/fisiología , Memoria a Corto Plazo/fisiología , Modelos Neurológicos , Percepción Visual/fisiología , Adulto , Electroencefalografía , Potenciales Evocados , Femenino , Lateralidad Funcional , Humanos , Individualidad , Masculino , Pruebas Neuropsicológicas , Adulto Joven
14.
Proc Natl Acad Sci U S A ; 109(28): E1990-9, 2012 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-22733755

RESUMEN

Over the last decades, the visual-search paradigm has provided a powerful test bed for competing theories of visual selective attention. However, the information required to decide upon the correct motor response differs fundamentally across experimental studies, being based, for example, on the presence, spatial location, or identity of the target item. This variability raises the question as to whether estimates of the time taken for (i) focal-attentional selection, (ii) deciding on the motor response, and (iii) response execution generalize across search studies or are specific to the demands of a particular task set. To examine this issue, we presented physically identical stimulus material in four different search task conditions, requiring target localization, detection, discrimination, or compound responses, and combined mental chronometry with two specific electroencephalographic brain responses that are directly linkable to either preattentive or postselective levels of visual processing. Behaviorally, reactions were fastest for localization, slowest for compound responses, and of intermediate speed for detection and discrimination responses. At the electroencephalographic level, this effect of task type manifested in the timing of the stimulus- and response-locked lateralized readiness potential (indexing motor-response decisions), but not posterior contralateral negativity (indexing focal-attentional selection), component. This result demonstrates that only the stage of preattentive visual coding generalizes across task settings, whereas processes that follow focal target selection are dependent on the nature of the task. Consequently, this task set-specific pattern has fundamental implications for all types of experimental paradigms, within and beyond visual search, that require humans to generate motor responses on the basis of external sensory stimulation.


Asunto(s)
Encéfalo/fisiología , Visión Ocular , Atención/fisiología , Conducta , Encéfalo/patología , Toma de Decisiones , Discriminación en Psicología/fisiología , Electrodos , Electroencefalografía/métodos , Femenino , Humanos , Masculino , Destreza Motora , Prevalencia , Tiempo de Reacción/fisiología , Reproducibilidad de los Resultados , Factores de Tiempo , Percepción Visual/fisiología
15.
J Vis ; 14(3): 26, 2014 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-24648196

RESUMEN

Behavioral and electrophysiological evidence is presented suggesting that, in visual search for feature singleton targets, multidimensional signals are integrated at a preselective stage of processing. Observers searched for a target that was consistently defined by the same features, but differed from the variable context either nonredundantly by one or redundantly by two dimensionally different features. The behavioral results showed reaction time redundancy gains and evidence of coactive processing, and the electrophysiological analyses revealed the latency of the N2pc component of the event-related potential (ERP) to be expedited by redundant relative to nonredundant displays, while the response-related lateralized readiness potential (LRP) remained unaffected. These findings suggest that target signal integration in singleton search paradigms occurs pre-attentively, that is, prior to focal-attentional target selection, with observers basing their responses on the detection of featureless saliency signals, even under conditions in which the target features remain constant and are known in advance. These results have implications for theories assuming top-down influences in feature detection.


Asunto(s)
Atención/fisiología , Reconocimiento Visual de Modelos/fisiología , Tiempo de Reacción/fisiología , Adulto , Electroencefalografía , Potenciales Evocados , Femenino , Humanos , Masculino , Detección de Señal Psicológica , Adulto Joven
16.
Cereb Cortex ; 22(7): 1554-63, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21903593

RESUMEN

Visual search for feature singletons is slowed when a task-irrelevant, but more salient distracter singleton is concurrently presented. While there is a consensus that this distracter interference effect can be influenced by internal system settings, it remains controversial at what stage of processing this influence starts to affect visual coding. Advocates of the "stimulus-driven" view maintain that the initial sweep of visual processing is entirely driven by physical stimulus attributes and that top-down settings can bias visual processing only after selection of the most salient item. By contrast, opponents argue that top-down expectancies can alter the initial selection priority, so that focal attention is "not automatically" shifted to the location exhibiting the highest feature contrast. To precisely trace the allocation of focal attention, we analyzed the Posterior-Contralateral-Negativity (PCN) in a task in which the likelihood (expectancy) with which a distracter occurred was systematically varied. Our results show that both high (vs. low) distracter expectancy and experiencing a distracter on the previous trial speed up the timing of the target-elicited PCN. Importantly, there was no distracter-elicited PCN, indicating that participants did not shift attention to the distracter before selecting the target. This pattern unambiguously demonstrates that preattentive vision is top-down modifiable.


Asunto(s)
Atención/fisiología , Mapeo Encefálico/métodos , Señales (Psicología) , Inhibición Psicológica , Reconocimiento Visual de Modelos/fisiología , Estimulación Luminosa/métodos , Corteza Visual/fisiología , Adulto , Discriminación en Psicología/fisiología , Femenino , Humanos , Masculino , Análisis y Desempeño de Tareas , Adulto Joven
17.
J Vis ; 13(3)2013 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-23912067

RESUMEN

In classic visual pop-out search, response times are slowed remarkably when participants are required to precisely identify (e.g., vertical vs. horizontal orientation) as compared to simply localize (e.g., left vs. right position) a feature singleton target. This cost associated with stimulus identification has been recently proposed (Töllner, Rangelov, & Müller, 2012) to derive from the engagement of postselective recurrent processes that via feedback connections extract the information required for motor-response selection. Here, we examined whether the contralateral delay activity (CDA), an asymmetric neural marker generally assumed to reflect active maintenance of stimulus information in visual short-term memory (vSTM), may further index the degree of postselective processing requirements in visual search. Employing a compound-search task, we selectively manipulated the ease/difficulty of identifying the response-critical target orientation attribute (horizontal vs. vertical)--irrespective of the target-defining color feature (red vs. green)--by introducing different levels of stimulus-background contrast. As expected, we found a monotonic reaction time increase to be associated with gradually increasing CDA magnitudes as the stimulus contrast decreased. Thus, our findings provide direct evidence that CDA activations provide a useful tool to estimate the amount of postselective recurrent processing recruited to extract detailed object information from vSTM.


Asunto(s)
Sensibilidad de Contraste/fisiología , Percepción de Forma/fisiología , Adulto , Atención/fisiología , Femenino , Humanos , Masculino , Memoria a Corto Plazo/fisiología , Orientación , Estimulación Luminosa , Tiempo de Reacción/fisiología , Adulto Joven
18.
Psychophysiology ; 60(12): e14375, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-37417320

RESUMEN

Singleton distractors may inadvertently capture attention, interfering with the task at hand. The underlying neural mechanisms of how we prevent or handle distractor interference remain elusive. Here, we varied the type of salient distractor introduced in a visual search task: the distractor could be defined in the same (shape) dimension as the target, a different (color) dimension, or a different (tactile) modality (intra-dimensional, cross-dimensional, and, respectively, cross-modal distractor, all matched for physical salience); and besides behavioral interference, we measured lateralized electrophysiological indicators of attentional selectivity (the N2pc, Ppc, PD , CCN/CCP, CDA, and cCDA). The results revealed the intra-dimensional distractor to produce the strongest reaction-time interference, associated with the smallest target-elicited N2pc. In contrast, the cross-dimensional and cross-modal distractors did not engender any significant interference, and the target-elicited N2pc was comparable to the condition in which the search display contained only the target singleton, thus ruling out early attentional capture. Moreover, the cross-modal distractor elicited a significant early CCN/CCP, but did not influence the target-elicited N2pc, suggesting that the tactile distractor is registered by the somatosensory system (rather than being proactively suppressed), without, however, engaging attention. Together, our findings indicate that, in contrast to distractors defined in the same dimension as the target, distractors singled out in a different dimension or modality can be effectively prevented to engage attention, consistent with dimension- or modality-weighting accounts of attentional priority computation.


Asunto(s)
Atención , Electroencefalografía , Humanos , Electroencefalografía/métodos , Atención/fisiología , Tiempo de Reacción/fisiología , Fenómenos Electrofisiológicos , Percepción Visual/fisiología
19.
J Cogn Neurosci ; 23(1): 137-50, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20044891

RESUMEN

The redundant-signals effect (RSE) refers to a speed-up of RT when the response is triggered by two, rather than just one, response-relevant target elements. Although there is agreement that in the visual modality RSEs observed with dimensionally redundant signals originating from the same location are generated by coactive processing architectures, there has been a debate as to the exact stage(s)--preattentive versus postselective--of processing at which coactivation arises. To determine the origin(s) of redundancy gains in visual pop-out search, the present study combined mental chronometry with electrophysiological markers that reflect purely preattentive perceptual (posterior-contralateral negativity [PCN]), preattentive and postselective perceptual plus response selection-related (stimulus-locked lateralized readiness potential [LRP]), or purely response production-related processes (response-locked LRP). As expected, there was an RSE on target detection RTs, with evidence for coactivation. At the electrophysiological level, this pattern was mirrored by an RSE in PCN latencies, whereas stimulus-locked LRP latencies showed no RSE over and above the PCN effect. Also, there was no RSE on the response-locked LRPs. This pattern demonstrates a major contribution of preattentive perceptual processing stages to the RSE in visual pop-out search, consistent with parallel-coactive coding of target signals in multiple visual dimensions [Müller, H. J., Heller, D., & Ziegler, J. Visual search for singleton feature targets within and across feature dimensions.


Asunto(s)
Atención/fisiología , Discriminación en Psicología/fisiología , Potenciales Evocados Visuales/fisiología , Tiempo de Reacción/fisiología , Percepción Visual/fisiología , Adulto , Análisis de Varianza , Mapeo Encefálico , Percepción de Color/fisiología , Variación Contingente Negativa/fisiología , Electroencefalografía/métodos , Femenino , Lateralidad Funcional , Humanos , Masculino , Orientación/fisiología , Reconocimiento Visual de Modelos , Estimulación Luminosa/métodos , Adulto Joven
20.
Psychophysiology ; 58(12): e13923, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34370887

RESUMEN

Research on attentional control within real-world contexts has become substantially more feasible and thus frequent over the past decade. However, relatively little is known regarding how these processes may be influenced by common naturalistic behaviors such as engaging in physical activity, which is thought to modulate the availability of neurometabolic resources. Here, we used an event-related potential (ERP) approach to determine whether various intensities of aerobic exercise might affect the concurrent performance of attentional control mechanisms. Participants performed an additional-singleton visual search task across three levels of aerobic activity while seated on a stationary bicycle: at rest, during moderate-intensity exercise, and during vigorous-intensity exercise. In addition to behavioral measures, attentional processing was assessed via lateralized ERPs referencing target selection (PCN) and distractor suppression (PD ) mechanisms. Whereas engaging in exercise resulted in speeded response times overall, moderate-intensity exercise was found to uniquely eliminate the expression of distractor interference by the PCN while also giving rise to an unanticipated distractor-elicited Ppc. These findings demonstrate workload-specific and object-selective influences of aerobic exercise on attentional processing, providing insights not only for approaching attention in real-world contexts but also for understanding how attentional resources are used overall.


Asunto(s)
Atención/fisiología , Potenciales Evocados/fisiología , Ejercicio Físico/fisiología , Desempeño Psicomotor/fisiología , Percepción Visual/fisiología , Electroencefalografía , Femenino , Humanos , Masculino , Adulto Joven
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