Effects of eye position on event-related potentials during auditory selective attention

Event-related potentials (ERPs) were recorded from normal subjects who received random sequences of tone pips from loudspeakers located to the left and right of a central point. The task was to detect occasional higher pitched tones (targets) from one designated speaker. The negative difference (Nd) wave between ERPs for relevant and irrelevant tones was largest when subjects fixated on the relevant speaker, smallest when subjects fixated on the irrelevant speaker, and intermediate in a central fixation. In addition, the Nd modulation for the left tones was produced by the more negative (or less positive) shift of irrelevant-stimulus ERPs and the less negative shift of relevant-stimulus ERPs associated with fixating away from the relevant speaker. These findings suggest the possibility of both facilitatory and inhibitory effects of eye position on auditory spatial attention. The substantial modulation of ERPs due to eye position also indicated the necessity of fixation control in auditory attention ERP research.     

Effects of attention and semantic relation on event-related potentials in a picture-word naming task

The interactive effects of attention and semantic relation on event-related potential (ERP) waveforms were examined during a naming task in which the physical stimulus array was the same across conditions. Superimposed picture-word pairs were presented in which the meaning of the words and pictures was congruent, semantically associated, or incongruent. In separate conditions, participants named words or pictures while ignoring the other stimulus. When words were attended, the superimposed pictures modulated the amplitude of P240 waves at posterior sites compared with when words were presented individually, but had no effect on N450 waves. In contrast, when pictures were attended to, the superimposed incongruent words elicited larger amplitude N450 waves at anterior sites than did congruent words or individually presented pictures. These effects affirm the independent processing of words and pictures during attention and are consistent with automatic and controlled processing of words and pictures, respectively. They also illustrate the endogenous nature of these late ERP waves.     

Effects of nicotine on visuo-spatial selective attention as indexed by event-related potentials

Nicotine has been shown to specifically reduce reaction times to invalidly cued targets in spatial cueing paradigms. In two experiments, we used event-related potentials to test whether the facilitative effect of nicotine upon the detection of invalidly cued targets is due to a modulation of perceptual processing, as indexed by early attention-related event-related potential components. Furthermore, we assessed whether the effect of nicotine on such unattended stimuli depends upon the use of exogenous or endogenous cues. In both experiments, the electroencephalogram was recorded while non-smokers completed discrimination tasks in Posner-type paradigms after chewing a nicotine polacrilex gum (Nicorette 2 mg) in one session and a placebo gum in another session. Nicotine reduced reaction times to invalidly cued targets when cueing was endogenous. In contrast, no differential effect of nicotine on reaction times was observed when exogenous cues were used. Electrophysiologically, we found a similar attentional modulation of the P1 and N1 components under placebo and nicotine but a differential modulation of later event-related potential components at a frontocentral site. The lack of a drug-dependent modulation of P1 and N1 in the presence of a behavioral effect suggests that the effect of nicotine in endogenous visuo-spatial cueing tasks is not due to an alteration of perceptual processes. Rather, the differential modulation of frontocentral event-related potentials suggests that nicotine acts at later stages of target processing.     

选择性注意与事件相关电位P300研究

事件相关电位（ＥＲＰｓ）常用来研究语义信息的感知，识别编码等易化过程，受试者给予汉语词汇作业刺激，靶刺激以２０％的概率随机呈现，被视觉感知，结果发现Ｐ３００的波幅及潜伏期较敏感地反映语义信息传递及过程，相比较而言靶刺激上发Ｐ３００有较大波幅，较短潜伏期和半球不对称性。     

The nature of selective attention effects on auditory event-related potentials

The purpose of the research reported here was to examine a number of issues relating to the nature of selective attention effects on auditory event-related potentials (ERPs), namely, to determine the relative contribution of N1 and slow wave (SW) to the early and late components of Nd respectively, where Nd is defined as the negative shift of attended ERPs relative to unattended ERPs; to examine whether individual differences in Nd morphology are related to performance and the strategies that subjects use; and to determine the contribution of changes in the attended and unattended ERPs to Nd. Auditory ERPs were recorded from subjects as they carried out an auditory selective attention task and a visual target detection task. The auditory selective attention task was a multidimensional task in which stimuli varied on location, pitch and duration and in which the subject's task was to pay attention to a particular location/pitch combination and respond whenever they detected a long-duration target tone. In the visual target detection task, subjects were required to respond whenever they detected a colour change in a light-emitting diode which also acted as a fixation point. Auditory ERPs recorded during the visual task were used to provide a measure of exogenous components uncontaminated by differential effects of selective processing of auditory stimuli. The results suggested that early Nd and N1 are independently generated as Nd did not exhibit the contralateral scalp focus typical of N1, and that late Nd is independent of SW. While substantial differences in Nd morphology were observed over subjects, these differences showed no consistent relationships to performance or to task strategies. Comparison of auditory ERPs during active auditory attention with auditory ERPs recorded during the visual control task indicated that there was an early negative shift of the attended ERP, a later negative shift of the attended ERP which had a frontal focus and a later positive shift of the unattended ERP. These results suggest that there are active processes involved in the processing of stimuli from both the attended and unattended source.     

Effects of perceptual context on event-related brain potentials during auditory spatial attention

The effects of auditory spatial attention on event-related brain potentials (ERPs) were examined in situations that promoted stream segregation. Short and long noise bursts were presented at three azimuth locations and listeners were asked to respond to the longer sounds occurring at either the right- or left-most location. In the baseline condition, the three sound sources were evenly spaced apart. In the distractor clustering conditions, middle and far sounds were clustered. In the attended clustering conditions, middle and attended sounds were clustered. ERP indices of attention, isolated as negative difference (Nd) waves, were greater over the hemisphere contralateral to the attended location. Nd waves were also larger when the middle sounds were moved toward the far distractors, consistent with an object-based gradient of auditory attention in which higher order information provided by the perceptual context influences selective processing.     

Perceptual context and the selective attention effect on auditory event-related brain potentials

Two experiments examined the effect of the perceptual context established through tonal grouping on neuroelectric responses during selective listening. Subjects monitored one of the extreme pitches in four-pitch tone sequences and detected rare longer tones of the designated pitch. In the first study, tonal grouping was manipulated by changing the tonal separation between the extreme pitches and their nearest neighbor, keeping the extreme pitches constant. Grouping increased the negativity of the attended–unattended difference potential. A second study examined the effect of grouping on the attention-related negativity when it opposed the effect of physical similarity. The proximity of extreme pitches varied, keeping the middle pitches constant. The effect of grouping on event-related potentials (ERPs) for the middle pitches was varied according to the tone being attended. ERPs for the middle tone adjacent to the attended tone became more negative with grouping, whereas ERPs for the distant middle tone became less negative with grouping. These effects suggest that the attention-related negativity is sensitive to contextual information.     

维持注意与选择注意具有不同的脑机制：来自事件相关电位的证据

BACKGROUND: At present, researches about attention mainly concentrate on the relationship between attention and other psychological phenomena, but studies concerning different types of attention itself (sustained attention versus selective attention) are few. OBJECTIVE: To investigate the brain mechanisms of sustained and selective attentions which have different roles in the cognitive process. METHODS: Event-related potentials (ERPs) were measured when 18 college students’ participants (half male and half female) were performing selective and sustained attention tasks. The program was written in E-Prime and displayed on a computer, and the experimental task was adapted from Karl et al. reported experimental paradigm, including selective attention and sustained attention tasks. The time of fixation point given was 500 ms, and the time of three randomly abreast pictures given was 300 ms. All the participants were asked to make rapid and accurate response as much as possible. RESULTS AND CONCLUSION: The ERPs elicited by the two attention tasks were different in the aspects of time process, wave crest and latency. The brain regions activated by the sustained attention were wider than those by selective attention. The ERPs elicited by the sustained attention mainly presents as positive waves, whereas those elicited by the selective attention were reflected as both positive and negative waves. The EPRs elicited by the sustained attention were N100 and N250, but in the metaphase, selective attention elicited the P180. These may indicate that event choice appears in the middle stage of the task. Besides, the reversion of EPRs elicited by the two attention tasks in the anterior and posterior scalp is likely to be a generality of all attentions. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

Motor and nonmotor event-related potentials during a complex processing task

Identification of the necessary stimulus properties to elicit the stimulus preceding negativity (SPN) has been the impetus for numerous research studies. The current study was conducted to explore the possibility that the SPN is an index of cognitive resource allocation. An auditory warning stimulus (S1) indicated whether an easy or difficult discrimination would occur at S2. The SPN was collected before a nonmotor discrimination task (S2) that consisted of identifying the higher of two bars. To eliminate the influence of motor processing prior to S2, a button press on the side of the higher bar was held until perception of a response cue (S3). Additionally, P3, contingent negative variation (CNV), and behavioral measures were collected to assist in assessing the SPN. Results indicated that although the SPN exhibited increased negativity, no differences were observed based on task difficulty. However, task difficulty did affect P3 data for both the warning tone and the discrimination task, an effect not observed for the CNV. Overall, the data did not support that hypothesis that the SPN provides an index of cognitive demand.     

Effects of divided attention to visual and auditory stimuli on event-related potentials

Effects of cross-modal divided attention on event-related potentials (ERPs) were examined. Tone pips through either left or right headphones, and colored words, either red or blue on a CRT display were presented in random order with equal probabilities (.25). Each class of stimuli included rare target tones or words. Eight subjects were instructed to attend 1, 2, 3 or all of four classes of stimuli in various combinations and to press a button quickly when targets occurred in the attending classes. ERPs to non-target stimuli in each class were recorded. Attention-related negative components of ERPs were largest when attention was focused upon only 1 class of stimuli, and their amplitudes decreased when attention was divided. A greater attenuation of ERPs was caused by the intra- rather than inter-modally divided attentions. The results suggest that the attention-related negative components may reflect the limitation of capacity or interference among sub-mechanisms in each of visual and auditory modalities.     

Children's event-related potentials of auditory selective attention vary with their socioeconomic status

Past research suggests a link between socioeconomic status (SES) and brain processes in children, but direct evidence from neuroimaging is scarce. The authors investigated the relationships among SES, performance, and the neural correlates of auditory selective attention, by comparing event-related potentials (ERPs) in lower- and higher-SES preadolescent children during a task in which they attended to two types of pure tones but ignored two other types. Our hypothesis was that, at comparable performance levels, higher-SES children ignore distracters (the unattended, irrelevant tones) while lower-SES children attend equally to distracters and to targets (the attended, relevant tones). The authors found that ERP waveform differences between attended and unattended tones (Nd, difference negativity) were significant in the higher-SES but not in the lower-SES group. However, the groups did not differ in reaction times or accuracy. Electroencephalographic power analysis revealed a differential pattern of theta activity concomitant with irrelevant tones for the two groups, indicating that although they performed similarly the children from these groups recruited different neural processes. Lower-SES children, the authors suggest, deployed supplementary resources to also attend to irrelevant information.     

Effects of aging on event-related brain potentials and reaction times in an auditory oddball task

Auditory event-related potentials (ERPs) were recorded from 71 healthy individuals between 18 and 82 years of age during performance of a disjunctive reaction time task in an auditory oddball paradigm. The effects of aging on reaction times and on the latencies, amplitudes, and distributions of each of the main ERP components were examined. No significant slowing of the reaction times of the elderly subjects was observed in relation to the younger ones. The peak latencies of both the N1 and P2 components elicited by standard tones were slightly but significantly slowed with age. In the ERPs of target tones, the later, endogenous components (N2, P3, and SW) showed linear increases in latency as a function of age; the later the component, the longer the age-related delay. In general, aging was associated with less negativity (both N2 and SW) and more positivity (P3) over the anterior scalp, together with a smaller P3 and a more pronounced N2 over posterior scalp areas. Most of the effects observed in target ERPs were also evident in the difference waves derived from subtraction of the standard from the target ERPs, although the slope of the age-related latency increase of N2 was shallower and that of the P3 was steeper in the difference ERPs. These findings are discussed in relation to previous accounts of ERP changes with aging.     

Modulation of event-related potentials by word repetition: The role of visual selective attention

Event-related potentials (ERPs) were recorded while subjects viewed visually presented words, some of which occurred twice. Each trial consisted of two colored letter strings, the requirement being to attend to and make a word/non word discrimination for one of the strings. Attention was manipulated by color in Experiment 1, and color and a precue were used in Experiment 2. As in previous ERP studies of word repetition, a positive offset to repeated words developed when both first and second presentations were the focus of attention. In Experiment 2, ERPs showed evidence of positive-going repetition effects in all conditions in which at least one of the two presentations of the repeated word was attended. In the visual modality, the positive-going ERP repetition effect occurs only when at least one of the two presentations of a repeated item is the object of attention, which suggests that one or more of the processes reflected by the effect is capacity limited.     

Stimulus selection during auditory spatial attention as expressed by event-related potentials

Selective listening to stimuli with certain physical features, such as pitch or location, is reflected by an event-related brain-potential (ERP) component called the processing negativity (PN). PN may reflect a matching or comparison process between the sensory inflow and the hypothesized ‘attentional trace’. The latter is an actively formed and maintained neuronal representation of the physical features defining the relevant stimulus. According to this matching theory of selective attention, the better the sensory input corresponds to the attentional trace the longer the stimulus is processes (as reflected by a larger and longer PN). This theory is supported by the experiment in which the relevant and irrelevant stimuli were separated from one another in pitch. It was found that even the irrelevant stimuli elicited PN, and further that this PN was larger the smaller the pitch separation between the eliciting stimuli and the relevant stimuli. The largest PN was elicited by the relevant stimuli. The present study finds analogous results when the relevant and irrelevant stimuli are separated in spatial origin rather than in pitch.     

Auditory event-related potentials in attention and reading disabled boys

Event-related potentials (ERPs) were recorded from 4 groups of children: (1) reading disabled, (2) attentional deficit disorder with hyperactivity, (3) attentional deficit disorder without hyperactivity, and (4) normal controls. Subjects were instructed to press a button to a low probability tone (target, P = 0.168) and to ignore all other events which included a high probability tone (non-target, P = 0.664) and an unexpected novel sound (P = 0.168). The amplitude of several late ERP components and the latency of the P3b component were examined. As in a previously reported visual study with the same sample of children, the overall amplitude of the P3b component was significantly smaller in all the clinical groups than in controls. Two other late components (slow wave and Pc) were also smaller in the clinical groups than in controls. P3 latency did not, however, differentiate the groups.     

Effects of low-frequency whole-body vibration on motor-evoked potentials in healthy men

The aim of this study was to determine whether low-frequency whole-body vibration (WBV) modulates the excitability of the corticospinal and intracortical pathways related to tibialis anterior (TA) muscle activity, thus contributing to the observed changes in neuromuscular function during and after WBV exercise. Motor-evoked potentials (MEPs) elicited in response to transcranial magnetic stimulation (TMS) of the leg area of the motor cortex were recorded in TA and soleus (SOL) muscles of seven healthy male subjects whilst performing 330 s continuous static squat exercise. Each subject completed two conditions: control (no WBV) and WBV (30 Hz, 1.5 mm vibration applied from 111 to 220 s). Five single suprathreshold and five paired TMS were delivered during each squat period lasting 110 s (pre-, during and post-WBV). Two interstimulus intervals (ISIs) between the conditioning and the testing stimuli were employed in order to study the effects of WBV on short-interval intracortical inhibition (SICI, ISI = 3 ms) and intracortical facilitation (ICF, ISI = 13 ms). During vibration relative to squat exercise alone, single-pulse TMS provoked significantly higher TA MEP amplitude (56 ± 14%, P = 0.003) and total area (71 ± 19%, P = 0.04), and paired TMS with ISI = 13 ms provoked smaller MEP amplitude (−21 ± 4%, P = 0.01) but not in SOL. Paired-pulse TMS with ISI = 3 ms elicited significantly lower MEP amplitude (TA, −19 ± 4%, P = 0.009; and SOL, −13 ± 4%, P = 0.03) and total area (SOL, −17 ± 6%, P = 0.02) during vibration relative to squat exercise alone in both muscles. Tibialis anterior MEP facilitation in response to single-pulse TMS suggests that WBV increased corticospinal pathway excitability. Increased TA and SOL SICI and decreased TA ICF in response to paired-pulse TMS during WBV indicate vibration-induced alteration of the intracortical processes as well.     

健康人事件相关电位及心理学相关性研究

目的：探讨不同年龄健康人听觉事件相关电位（ERP）及其与心理测验间关系。方法：对不同年龄组健康者进行听觉ERP检测，以"oddball序列"刺激从Cz点引出P3，测其波幅和潜伏期。对其中30名成人进行韦氏智力量表和记忆量表测验。结果：P3潜伏期以儿童期最短，并随年龄增长逐渐延长，P3波幅儿童期明显高于成年人。成年组P3潜伏期与总智商、记忆商、及某些分测验呈显著负相关，而P3波幅与心理测验无明显相关关系。结论：不同年龄者ERP正常值不同，ERP能够反映智能的某些方面，特别倾向于反映言语和记忆能力。     

Processing of auditory stimuli during auditory and visual attention as revealed by event-related potentials

Auditory event-related brain potentials (ERPs) were recorded during auditory and visual selective attention tasks. Auditory stimuli consisted of frequent standard tones (1000 Hz) and infrequent deviant tones (1050 Hz and 1300 Hz) delivered randomly to the left and right ears. Visual stimuli were vertical line gratings randomly presented on a video monitor at mean intervals of 6 s. During auditory attention, the subject attended to the stimuli in a designated ear and responded to the 1300-Hz deviants occurring among the attended tones. During visual attention, the subject responded to the occasional visual stimuli. ERPs for tones delivered to the attended ear were negatively displaced relative to ERPs elicited by tones delivered to the unattended ear and to ERPs elicited by auditory stimuli during visual attention. This attention effect consisted of negative difference waves with early and late components. Mismatch negativities (MMNs) were elicited by 1300-Hz and 1050-Hz deviants irrespective of whether they occurred among attended or unattended tones. MMN amplitudes were unaffected by attention, supporting the proposal that the MMN is generated by an automatic cerebral discrimination process.     

Nonspatial intermodal selective attention is mediated by sensory brain areas: evidence from event-related potentials

The present study focuses on the question of whether inter- and intramodal forms of attention are reflected in activation of the same or different brain areas. ERPs were recorded while subjects were presented a random sequence of visual and auditory stimuli. They were instructed to attend to nonspatial attributes of either auditory or visual stimuli and to detect occasional target stimuli within the attended channel. An occipital selection negativity was found for intramodal attention to visual stimuli. Visual intermodal attention was also manifested in a similar negativity. A symmetrical dipole pair in the medial inferior occipital areas could account for the intramodal effects. Dipole pairs for the intermodal attention effect had a slightly more posterior location compared to the dipole pair for the intramodal effect. Auditory intermodal attention was manifested in an early enhanced negativity overlapping with the N1 and P2 components, which was localized using a symmetrical dipole pair in the lateral auditory cortex. The onset of the intramodal attention effect was somewhat later (around 200 ms), and was reflected in a frontal processing negativity. The present results indicate that intra- and intermodal forms of attention were indeed similar for visual stimuli. Auditory data suggest the involvement of multiple brain areas.     

Effects of inter-stimulus interval on skin conductance responses and event-related potentials in a Go/NoGo task

Skin conductance responses (SCRs) to NoGo stimuli have been found to be smaller than to Go stimuli, possibly due to their diminished task relevance. These findings have been obtained at inter-stimulus intervals (ISI) that were unusually short for SCR recordings. Therefore, we tested whether the same findings would also hold at longer ISIs. Simultaneously, effects of ISI duration on the NoGo-N2 and-P3 components of event-related brain potentials (ERPs) were assessed. Go and NoGo stimuli were equiprobable while ISI varied between 2, 5, and 8 s. Although increasing the ISI-enhanced SCR amplitudes in general, it did not modulate the attenuation of the response to NoGo relative to Go stimuli. When considered as difference between NoGo and Go conditions, neither the NoGo-N2 nor the NoGo-P3 was affected by ISI variation. Together, these data confirm the feasibility of co-registering ERPs and SCRs.