Selective Attention Conditions Research Articles

Cognitive performance in older males is associated with growth hormone secretion

Decreases in GH secretion with age may contribute to cognitive changes associated with aging. We evaluated the relation between GH secretion and cognition in elderly males by assessing correlations between GH secretion and performance on cognitive tests in conjunction with recording of event-related potentials (ERPs) to assess underlying neurophysiological mechanisms. GH secretion of 17 elderly male participants was assessed by a GHRH-GHRP-6 test. Standardized neuropsychological tests were used to assess cognitive function. EEG/ERPs were recorded to assess on-line electrocortical correlates of sensory-cortical processing and selective attention. GH secretion was significantly correlated with target detections and speed of responding in the selection-potential task. Furthermore, GH peak was significantly correlated with the performance letter-digit span test. The present data confirm that cognitive performance in elderly males is associated with GH secretion, with respect to target detection and speed of responding in conditions of selective attention, short-term memory, and basic processing speed.

Altered spatial distribution of visual attention in near and far space after early deafness

Early deafness results in a redistribution of more attentional resources to the visual periphery in near space, specifically under conditions of selective attention, probably to compensate for the loss of auditory alertness to potentially dangerous stimuli from outside the current attentional focus. It remains poorly understood, however, whether spatial distribution of attention in far space is altered by early deafness as well. In the present study, we investigated whether and how early deafness alters the distribution of visuospatial attention in far space, compared to hearing controls. We asked deaf individuals and hearing controls to perform a flanker task with either peripheral or central distractors, either in near or far space. Sizes of compatibility effect were used to assess the amount of attentional resources received by the peripheral and central distractors. In near space, peripheral distractors induced significantly larger compatibility effect in deaf individuals than in hearing controls while central distractors induced significantly larger compatibility effect in hearing controls than in deaf individuals. On the other hand in far space, although peripheral distractors induced equivalent sizes of compatibility effect in the deaf and hearing groups, central distractors caused significant compatibility effect only in deaf individuals, but not in hearing controls. Our results suggest that early deafness results in a redistribution of visuospatial attention not only in near space but also in far space, with enhanced peripheral attention in near space and enhanced central attention in far space.

Further evidence that congenitally blind participants react faster to auditory and tactile spatial targets.

Congenital blindness is one of the rare human models to explore the role of experience-driven cross-modal compensation after early sensory deprivation. We re-examined spatial attention abilities in congenitally blind participants and sighted controls using a paradigm comparable to the one of our previous study (Collignon, Renier, Bruyer, Tranduy, & Veraart, 2006), except that this time the auditory and tactile stimuli were now presented in sequence. Although both groups performed the task with similar accuracy, we observed that blind participants had shorter reaction times than sighted controls for the detection of spatial targets in both sensory modalities. Moreover, this finding held true for both the selective and divided attention conditions. These results not only confirm previous reports on the superiority of the blind during auditory and tactile attention tasks, but also broaden our knowledge of the mechanisms underlying cross-modal compensation.

Beyond perception: Testing for implicit conceptual traces in high-load tasks

The present commentary addresses the main results obtained in the Butler and Klein [Butler, B. C., & Klein, R. (2009). Inattentional blindness for ignored words: Comparison of explicit and implicit memory tasks. Consciousness and Cognition, 18, 811–819.] study and discusses them in relation to the Perceptual Load Theory of Lavie [Lavie, N. (1995). Perceptual load as a necessary condition for selective attention. Journal of Experimental Psychology: Human Perception and Performance, 21, 451–68.]. The authors claim that the use of implicit indexes of conceptual distractor processing in high-load situations would be an important addition to the load literature, which would benefit the research field regardless of their positive or negative findings.

Spatial attention can modulate audiovisual integration at multiple cortical and subcortical sites

The role of attention in multisensory integration (MI) is presently uncertain, with some studies supporting an automatic, pre-attentive process and others suggesting possible modulation through selective attention. The goal of this functional magnetic resonance imaging study was to investigate the role of spatial attention on the processing of congruent audiovisual speech stimuli (here indexing MI). Subjects were presented with two simultaneous visual streams (speaking lips in the left and right visual hemifields) plus a single central audio stream (spoken words). In the selective attention conditions, the auditory stream was congruent with one of the two visual streams. Subjects attended to either the congruent or the incongruent visual stream, allowing the comparison of brain activity for attended vs. unattended MI while the amount of multisensory information in the environment and the overall attentional requirements were held constant. Meridian mapping and a lateralized 'speaking-lips' localizer were used to identify early visual areas and to localize regions responding to contralateral visual stimulations. Results showed that attention to the congruent audiovisual stimulus resulted in increased activation in the superior temporal sulcus, striate and extrastriate retinotopic visual cortex, and superior colliculus. These findings demonstrate that audiovisual integration and spatial attention jointly interact to influence activity in an extensive network of brain areas, including associative regions, early sensory-specific visual cortex and subcortical structures that together contribute to the perception of a fused audiovisual percept.

Influence of genetic variants modulating dopamine activity on the brain processing of auditory information (the P300 paradigm)

We studied the influence of catechol-O-methyl transferase gene (COMT) polymorphism on the parameters of components of auditory evoked potentials (EPs) recorded under the conditions of selective attention in mentally healthy relatives of patients with endogenous psychosis. A smaller N100 latency of the EP in response to an insignificant stimulus, smaller N100 amplitude of the EP in response to a significant stimulus, smaller N200 latency, and larger P300 amplitude were found in subjects with the Met/Met genotype (with a higher dopamine activity), and a larger P200 latency was found in Val/Val genotype carriers. There was no influence of MMN gene polymorphism on the mismatch negativity.

Functional magnetic resonance imaging (fMRI) of attention processes in presumed obligate carriers of schizophrenia: preliminary findings

BackgroundPresumed obligate carriers (POCs) are the first-degree relatives of people with schizophrenia who, although do not exhibit the disorder, are in direct lineage of it. Thus, this subpopulation of first-degree relatives could provide very important information with regard to the investigation of endophenotypes for schizophrenia that could clarify the often contradictory findings in schizophrenia high-risk populations. To date, despite the extant literature on schizophrenia endophenotypes, we are only aware of one other study that examined the neural mechanisms that underlie cognitive abnormalities in this group. The aim of this study was to investigate whether a more homogeneous group of relatives, such as POCs, have neural abnormalities that may be related to schizophrenia.MethodsWe used functional magnetic resonance imaging (fMRI) to collect blood oxygenated level dependent (BOLD) response data in six POCs and eight unrelated healthy controls while performing under conditions of sustained, selective and divided attention.ResultsThe POCs indicated alterations in a widely distributed network of regions involved in attention processes, such as the prefrontal and temporal (including the parahippocampal gyrus) cortices, in addition to the anterior cingulate gyrus. More specifically, a general reduction in BOLD response was found in these areas compared to the healthy participants during attention processes.ConclusionThese preliminary findings of decreased activity in POCs indicate that this more homogeneous population of unaffected relatives share similar neural abnormalities with people with schizophrenia, suggesting that reduced BOLD activity in the attention network may be an intermediate marker for schizophrenia.

Stroop Performance, Dissociation, and Trauma Exposure in a Community Sample of Children

ABSTRACT Extending previous research with adults, the current study examined Stroop task performance under selective and divided attention demands in a community sample of school-age children (N = 97). Stroop interference scores in both attention conditions were calculated. Higher levels of child-reported dissociation were associated with better interference control under divided attention conditions and worse control under selective attention conditions; lower levels of dissociation were associated with the opposite pattern. Both family violence exposure and Stroop interaction scores explained unique variance in dissociation scores. Although research with adults has generally assumed or implied that cognitive correlates of dissociation are a consequence of dissociation, the current findings with school-age children suggest that future research should evaluate executive function performance (in this case, interference control) as a possible risk factor for dissociation.

Selective attention increases both gain and feature selectivity of the human auditory cortex.

BackgroundAn experienced car mechanic can often deduce what's wrong with a car by carefully listening to the sound of the ailing engine, despite the presence of multiple sources of noise. Indeed, the ability to select task-relevant sounds for awareness, whilst ignoring irrelevant ones, constitutes one of the most fundamental of human faculties, but the underlying neural mechanisms have remained elusive. While most of the literature explains the neural basis of selective attention by means of an increase in neural gain, a number of papers propose enhancement in neural selectivity as an alternative or a complementary mechanism.Methodology/Principal FindingsHere, to address the question whether pure gain increase alone can explain auditory selective attention in humans, we quantified the auditory cortex frequency selectivity in 20 healthy subjects by masking 1000-Hz tones by continuous noise masker with parametrically varying frequency notches around the tone frequency (i.e., a notched-noise masker). The task of the subjects was, in different conditions, to selectively attend to either occasionally occurring slight increments in tone frequency (1020 Hz), tones of slightly longer duration, or ignore the sounds. In line with previous studies, in the ignore condition, the global field power (GFP) of event-related brain responses at 100 ms from the stimulus onset to the 1000-Hz tones was suppressed as a function of the narrowing of the notch width. During the selective attention conditions, the suppressant effect of the noise notch width on GFP was decreased, but as a function significantly different from a multiplicative one expected on the basis of simple gain model of selective attention.Conclusions/SignificanceOur results suggest that auditory selective attention in humans cannot be explained by a gain model, where only the neural activity level is increased, but rather that selective attention additionally enhances auditory cortex frequency selectivity.

Selective Effects of Cholinergic Modulation on Task Performance during Selective Attention

The cholinergic neurotransmitter system is critically linked to cognitive functions including attention. The current studies were designed to evaluate the effect of a cholinergic agonist and an antagonist on performance during a selective visual attention task where the inherent salience of attended/unattended stimuli was modulated. Two randomized, placebo-controlled, crossover studies were performed, one (n=9) with the anticholinesterase physostigmine (1.0 mg/h), and the other (n=30) with the anticholinergic scopolamine (0.4 mc/kg). During the task, two double-exposure pictures of faces and houses were presented side by side. Subjects were cued to attend to either the face or the house component of the stimuli, and were instructed to perform a matching task with the two exemplars from the attended category. The cue changed every 4-7 trials to instruct subjects to shift attention from one stimulus component to the other. During placebo in both studies, reaction time (RT) associated with the first trial following a cued shift in attention was longer than RT associated with later trials (p<0.05); RT also was significantly longer when attending to houses than to faces (p<0.05). Physostigmine decreased RT relative to placebo preferentially during trials greater than one (p<0.05), with no change during trial one; and decreased RT preferentially during the attention to houses condition (p<0.05) vs attention to faces. Scopolamine increased RT relative to placebo selectively during trials greater than one (p<0.05), and preferentially increased RT during the attention to faces condition (p<0.05). The results suggest that enhancement or impairment of cholinergic activity preferentially influences the maintenance of selective attention (ie trials greater than 1). Moreover, effects of cholinergic manipulation depend on the selective attention condition (ie faces vs houses), which may suggest that cholinergic activity interacts with stimulus salience. The findings are discussed within the context of the role of acetylcholine both in stimulus processing and stimulus salience, and in establishing attention biases through top-down and bottom-up mechanisms of attention.

Local–global interference is modulated by age, sex and anterior corpus callosum size

To identify attentional and neural mechanisms affecting global and local feature extraction, we devised a global–local hierarchical letter paradigm to test the hypothesis that aging reduces functional cerebral lateralization through corpus callosum (CC) degradation. Participants (37 men and women, 26–79 years) performed a task requiring global, local, or global + local attention and underwent structural MRI for CC measurement. Although reaction time (RT) slowed with age, all participants had faster RTs to local than global targets. This local precedence effect together with greater interference from incongruent local information and greater response conflict from local targets each correlated with older age and smaller callosal genu (anterior) areas. These findings support the hypothesis that the CC mediates lateralized local–global processes by inhibition of task-irrelevant information under selective attention conditions. Further, with advancing age smaller genu size leads to less robust inhibition, thereby reducing cerebral lateralization and permitting interference to influence processing. Sex was an additional modifier of interference, in that callosum–interference relationships were evident in women but not in men. Regardless of age, smaller splenium (posterior) areas correlated with less response facilitation from repetition priming of global targets in men, but with greater response facilitation from repetition priming of local targets in women. Our data indicate the following dissociation: anterior callosal structure was associated with inhibitory processes (i.e., interference from incongruency and response conflict), which are vulnerable to the effects of age and sex, whereas posterior callosal structure was associated with facilitation processes from repetition priming dependent on sex and independent of age.

Electrographic correlates of ?internal states? evoked by positive conditioned stimuli during operant training in dogs

Experiments were performed to address the energy characteristics (power spectra) of short-term (less than 1 sec) EEG reactions arising in different areas of the neocortex in response to positive conditioned stimuli presented in conditions of selective attention. These EEG reactions directly preceded the motor reactions, which consisted of a strong blow with the paw on a feeder pedal to obtain reinforcement. The energy levels of EEG reactions were 1.5-3 times greater than pre-stimulus levels. The frequency structures of the corresponding EEG reactions were divided into discrete frequency subgroups, including the traditional (1-30 Hz) and the gamma ranges (30-80 Hz) as well as higher-frequency components (80-200 Hz). In some cases, the greater proportionate increases in power occurred in the high-frequency band.

Attention to pain localization and unpleasantness discriminates the functions of the medial and lateral pain systems

Functional imaging studies have identified a matrix of structures in the brain that respond to noxious stimuli. Within this matrix, a division of function between sensory-discriminative and affective responses has so far been demonstrated by manipulating either pain intensity or unpleasantness under hypnosis in two different normal volunteer groups studied on separate occasions. Our study used positron emission tomography (PET) to demonstrate this division of function under more natural conditions in a healthy group of volunteers, using a CO(2) laser to provide nociceptive stimuli that selectively activate A-delta and C-fibres without contamination by touch sensations. We measured the differential cerebral responses to noxious and innocuous laser stimuli during conditions of selective attention to either the unpleasantness or location of the stimuli. Attention to location increased responses in the contralateral (right) primary somatosensory and inferior parietal cortices. This result implies that these components of the lateral pain system are concerned mainly with the localization of pain. In contrast, attention to unpleasantness increased responses in bilateral perigenual cingulate and orbitofrontal cortices, contralateral (right) amygdala, ipsilateral (left) hypothalamus, posterior insula, M1 and frontal pole. These areas comprise key components of the medial pain and neuroendocrine systems and the results suggest that they have a role in the affective response to pain. Our results indicate the importance of attentional effects on the pattern of nociceptive processing in the brain. They also provide the first clear demonstration, within a single experiment, of a major division of function within the neural pain matrix.

Effects of selective visual attention in the parietal and temporal areas of the human cortex using evoked potential data

Studies of 11 young subjects addressed the analysis of evoked potentials in the parietal and temporal areas to sequential presentation of visual symbols on the left and right sides; symbols were squares and circles and were observed passively and in conditions of selective attention to target stimuli presented to the subjects in random order and requiring rapid and precise motor responses. Comparison of monopolar evoked potentials in leads P3, P4, T3, T4, T5, and T6 with bipolar potentials in leads P3-T3, P3-T5, P4-T4, and P4-T6 in conditions of passive and selective attention showed that voluntary attention was accompanied by significant rearrangements in evoked activity in the parietal and temporal areas. This was evident as: 1) an increase in correlations between evoked potentials in the parietal and temporal areas; 2) stabilization of monopolar evoked potentials over time, i.e., increases in the correlations of sequential evoked potentials, in both associative visual areas; 3) stabilization of bipolar parietal-temporal evoked potentials in terms of increases in their sequential correlations. It is suggested that selective attention facilitates linked activity of the two associative areas, which is needed for performance of visual selection.

Neural gate keeping: the role of interhemispheric interactions in resource allocation and selective filtering.

The corpus callosum has been proposed to contribute to attention by modulating resource allocation between the hemispheres and filtering interhemispheric signal transmission (M. T. Banich, 1998). The resource allocation hypothesis predicts that interhemispheric interactions become more advantageous with increasing resource demands. The selective filtering hypothesis predicts that interhemispheric interactions become less advantageous as filtering requirements increase. The authors tested both predictions by comparing within- and across-hemisphere letter matching under dual-task (Experiment 1) and selective attention conditions (Experiment 2). Task-specific resource demands (i.e., letter processing load) alter the bihemispheric advantage, but the general demand imposed by an unrelated secondary task does not. Filtering requirements influenced the advantage from interhemispheric interactions, providing new evidence for the role of the corpus callosum in selective attention.

Auditory-Evoked Potentials and Selective Attention: Different Ways of Information Processing in Cannabis Users and Controls

The present study tested the hypothesis that chronic cannabis use leads to persistent attentional dysfunctions and that age of onset of cannabis use is a potential predictor of impaired test performance and information processing. Brain event-related potentials (ERPs) during a complex auditory selective attention task were recorded from 21 cannabis users divided into two groups according to age of onset and from 13 controls comparable with respect to age, IQ and educational background. Participants were instructed to detect target tones of a particular location, pitch and duration from a total sample of random frequencies. The study reveals that the latency of the greatest negative peak of ERPs (200 and 300 ms) to target tones was shorter in controls, while there was no clear difference between target and non-target within cannabis users. In addition, users displayed a reduced P₃ to target tones. This was more pronounced in early-onset cannabis users. These data suggest that chronic cannabis use relates to different types of information processing under conditions of selective attention. There is some evidence that users employed different strategies of attention allocation. The results are discussed with respect to possible underlying mechanisms and clinical implications.

The effects of aging on selective attention to touch: a reduced inhibitory control in elderly subjects?

This article aimed at disclosing differences in the brain mechanisms underlying selective attention between elderly and young subjects. We studied two populations of subjects, 17 elderly (mean age: 71.7) and 12 young (mean age: 26.9). Somatosensory evoked potentials (SEPs) to median nerve stimulation were recorded from 19 scalp electrodes in a neutral condition (NC), in which subjects were asked to disregard the electrical stimulation and in a selective attention condition (SAC), in which the subjects had to count tactile stimuli delivered on the same hand of the stimulated median nerve. In a further 3 old and in 3 young subjects, SEPs were recorded also in a distraction condition (DC), in which the subjects had to perform a mathematical task. The SEP amplitude increase during SAC was lower in old than in young subjects. Moreover, while in young subjects the N140 potential was identifiable only in SAC, in the elderly population it was already evoked during both NC and DC. Elderly subjects are probably unable to divert their attention from the median nerve electric stimuli during NC and DC and, therefore, have lower attention resources to invest during SAC. This may explain the recording of the attention-related N140 potential even in NC and DC and the lower SEP amplitude increase in SAC, observed in elderly subjects. These findings agree with recent hypotheses that suggest a decrease of the inhibitory control of the attention mechanisms during aging.

Divided Attention in Older But Not Younger Adults Is Impaired by Anxiety

It has been hypothesized that the disruptive effects of negative emotional states, such as anxiety and depression, may contribute to poorer performance in older age. Some studies have reported that higher levels of anxiety are associated with poorer cognitive performance in older adults but not younger adults. The author examined if age and anxiety interact with performance by comparing the performance of normal healthy younger and older adults on cognitive and motor tests under conditions of selective and divided attention. Ninety-two older adults (mean age=70.1 years, SD =7.1 years) and 78 younger adults (mean age=18.8 years, SD =1.9 years), matched on education, vocabulary, and self-reported health, performed a word-comparison and pursuit-rotor task under conditions of selective and divided attention. Anxiety was assessed using the Speilberger State-Trait anxiety scale. The hypothesis was supported: higher anxiety was associated with poorer divided attention performance in older, but not younger, adults. Anxiety was not associated with poorer motor performance in older adults. Implications of the results for cognitive-resource theories of aging cognition are discussed.

Long-term effects of covert face recognition

Covert face recognition has previously been thought to produce only very short-lasting effects. In this study we demonstrate that manipulating subjects' attentional load affects explicit, but not implicit memory for faces, and that implicit effects can persist over much longer intervals than is normally reported. Subjects performed letter-string tasks of high vs. low perceptual load (Lavie, N. (1995). Perceptual load as a necessary condition for selective attention. Journal of Experimental Psychology: Human Perception and Perfomance. 21, 451–468.), while ignoring task-irrelevant celebrity faces. Memory for the faces was then assessed using (a) a surprise recognition test for the celebrities' names, and (b) repetition priming in a face familiarity task. The load manipulation strongly influenced explicit recognition memory, but had no effect on repetition priming from the same items. Moreover, faces from the high load condition produced the same amount of priming whether they were explicitly remembered or not. This result resolves a long-standing anomaly in the face recognition literature, and is discussed in relation to covert processing in prosopagnosia.

Mismatch negativity of the color modality during a selective attention task to auditory stimuli in children with mental retardation

Event-related potentials (ERPs) in response to a stimulus change in the visual color modality were recorded in normal subjects and children with mental retardation (MR) under selective attention conditions with auditory stimuli. The paradigm included the presentation of a standard (blue color screen, B) or deviant (red, R, or greenish blue color screen, GB) visual stimulus, and a target or non-target tone burst stimulus. In Experiment 1, negativity of the subtracted waveform in response to visual stimuli with a latency of 250–280 ms was clearly observed in the ERPs of normal adults. These potentials prominently appeared at posterior sites in one condition, for which the deviant was GB, but were frontal site-dominant for the other condition. A P300 response to visual deviance was not observed in the GB-B paradigm and the subtracted negativity for this paradigm seemed to be more evident than that for the R-B paradigm. The subtracted negativities could be detected in the range of 180–400 ms after the stimulus onset in control children for the GB-B paradigm. The grand average waves of subtracted ERPs in normal children showed a similar distribution to that in normal adults. Similar subtracted potentials could be recorded with the same paradigm in children with MR, however, the negativities were different in waveform and spatial distribution than in controls. Therefore, the subtracted negativity of the present visual modality represented the analogue of the auditory mismatch negativity (MMN), and so-called ‘visual MMN’ was detectable in children and even in MR patients when the selective attention was directed to other stimuli.