Performance differences in reaction tasks are reflected in event-related brain potentials (ERPs)

The glycoprotein hormone alpha-subunit gene is expressed and differentially regulated in pituitary gonadotropes and thyrotropes. Previous gene expression studies suggested that cell specificity may be regulated by distinct DNA elements. We have identified an enhancer region between -4.6 and -3.7 kb that is critical for high level expression in both gonadotrope and thyrotrope cells of transgenic mice. Fusion of the enhancer to -341/+43 mouse alpha-subunit promoter results in appropriate pituitary cell specificity and transgene expression levels that are similar to levels observed with the intact -4.6 kb/+43 construct. Deletion of sequences between -341 and -297 resuited in a loss of high level expression and cell specificity, exhibited by ectopic transgene activation in GH-, ACTH-, and PRL-producing pituitary cells as well as in other peripheral tissues. Consistent with these results, transient cell transfection studies demonstrated that the enhancer stimulated activity of a -341/+43 alpha-promoter in both alphaTSH and alphaT3 cells, but it did not enhance alpha-promoter activity significantly in CV-1 cells. Removal of sequences between -341 and -297 allowed the enhancer to function in heterologous cells. Loss of high level expression and cell specificity may be due to loss of sequences required for binding of the LIM homeoproteins or the alpha-basal element 1. These data demonstrate that the enhancer requires participation by both proximal and distal sequences for high level expression and suggests that sequences from -341 to -297 are critical for restricting expression to the anterior pituitary.     

Structure and process in semantic memory: Evidence from event-related brain potentials and reaction times.

Through scalp measurements of the electrical activity of the brain (ERPs) recorded while Ss verified the truth of sentences relating exemplars and categories (e.g., all dogs are animals), inferences were made about aspects of semantic processing that were not directly reflected by overt responses. In particular, it is suggested that a negative ERP component that peaks about 400 msec after the onset of the sentence predicate (i.e., N400) is sensitive to structural aspects of semantic memory. The amplitude of this component was modulated by the relatedness of the subject and predicate terms, as well as the hierarchical level of both these terms, but was not sensitive to the truth value of a sentence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Personality, reaction time, and event-related potentials.

Reaction time (RT), movement time (MT), and the amplitude and latency of the P300 ERP were recorded from 30 Ss during the performance of 6 simple cognitive tasks. Extraversion was negatively associated with MT, a result that endorses the view that extraversion is determined, in part, by individual differences in motor mechanisms. Higher neuroticism scores were associated with faster P300 latency, a measure that is regarded as an index of stimulus evaluation time that is independent of response production. Paradoxically, higher neuroticism scores were associated with slower RT, a measure that is also regarded as an index of speed of information processing. Higher psychoticism scores were associated with smaller P300 amplitude, an effect that may be indicative of less attentional effort invested in the tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective auditory attention and early event-related potentials: A rejoinder.

Discusses the hypothesis of R. N??t?nen and P. T. Michie (see record 1980-29874-001) that selective auditory attention does not merely augment the N? component of the auditory evoked potential at 80–220 msec latency. Sequential effects, stimulus intensity, and the effect of information load are examined with regard to the hypothesis, and it is suggested that 2 distinct physiological processes are involved. (French abstract) (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Automatic and effortful processes in auditory memory reflected by event-related potentials. Age-related findings

The structures of the N-linked sugar chains in the PAS-6 glycoprotein (PAS-6) from the bovine milk fat globule membrane were determined. The sugar chains were liberated from PAS-6 by hydrazinolysis, and the pyridylaminated sugar chains were separated into a neutral (6N) and two acidic chains (6M and 6D), the acidic sugar chains then being converted to neutral sugar chains (6MN and 6DN). 6N was separated into two neutral fractions (6N13 and 6N5.5), while 6MN and 6DN each gave a single fraction (6MN13 and 6DN13). The structure of 6N5.5, which was the major sugar chain in PAS-6, is proposed to be Man alpha1 --> 6 (Man alpha1 --> 3) Man beta1 --> 4GlcNAc beta1 --> 4GlcNAc-PA; 6N13, 6MN13 and 6DN13 are proposed to be Gal beta1 --> 3Gal beta1 --> 4GlcNAc beta1 --> 2Man alpha1 --> 6 (Gal beta1 --> 3Gal beta1 --> 4GlcNAc beta1 --> 2Man alpha1 --> 3) Man beta1 --> 4GlcNAc beta1 --> 4 (Fuc alpha1 --> 6)GlcNAc-PA; 6M and 6D had 1 or 2 additional NeuAc residues at the non-reducing ends of 6MN13 and 6DN13, respectively.     

Differential effects of voluntary expectancies on reaction times and event-related potentials: Evidence for automatic and controlled expectancies.

Expectancy has been used to explain the effects of stimulus sequences both on reaction times (RTs) and on the P300 component of the human event-related potential. However, there are conflicting views about the control obtainable over these underlying expectancies. The effects of voluntary expectancies for stimulus changes or repetitions in random tone series on RTs and the P300 were compared. Ss responded according to either stimulus identity (Exp 1) or stimulus sequence (Exp 2). In both experiments, RTs were strongly affected by event expectedness. P300 amplitude, on the other hand, was affected (as a trend) only in Exp 2. Results suggest that there are at least 2 types of "expectancy," one that is largely automatic and inflexible, reflected in P300 amplitude, and a second, controlled process that is reflected mainly in RT. The latter type of expectancy appears to affect processing stages beyond stimulus evaluation and classification. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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.     

Localizing the development of covert attention in infants with scalp event-related potentials.

This study examined covert shifts of attention in infants aged 14, 20, and 26 weeks of age with scalp-recorded event-related potentials (ERPs). The infants were tested in a spatial cuing procedure. The reaction time (RT) to localize the target showed covert attention shifts (e.g., response facilitation or inhibition of return depending on cue–target stimulus onset asynchrony). There was a larger P1 ERP component on the valid trials than on the invalid trials or on the no-cue control trials. Presaccadic ERP potentials in response to the target were larger when it was in the cued location than when it was in uncued locations. There were increases from 14 to 26 weeks of age in the amount of inhibition of return, in the post-target-onset P1 effect. and in the presaccadic ERP potentials. These results suggest that cortical development parallels the development of covert orienting of attention and saccade planning in infants in this age range. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How Gorbachev primed Yeltsin: Analyses of associative priming in person recognition by means of reaction times and event-related brain potentials.

In this study, participants recognized target faces or names that were preceded by prime faces or names of related or unrelated persons. Associative priming effects on reaction times (RTs) and event-related brain potentials (ERPs) were equivalent for within-domain (e.g., face–face) and cross-domain (e.g., name–face) priming. Moreover, the ERP modulation due to priming was topographically equivalent for face and name targets. This suggests that priming of faces and names modulated the activity of the same brain sources, arguing for a postperceptual locus of priming. When combined effects of priming and target degradation were investigated, ERP priming effects were confined to time segments beyond 300 ms, whereas degradation effects started within the first 150 ms and were independent of priming. The findings suggest that associative priming in person recognition acts on domain-independent representations of person identity but not on perceptual processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interpretation bias in social anxiety as detected by event-related brain potentials.

Little is known about psychophysiological correlates of interpretation bias in social anxiety. To address this issue, the authors measured event-related brain potentials (ERPs) in high and low socially anxious individuals during a task wherein ambiguous scenarios were resolved with either a positive or negative ending. Specifically, the authors examined modulations of the P600, an ERP that peaks approximately 600 ms following stimulus onset and indexes violations of expectancy. Low-anxious individuals were characterized by an increased P600 to negative in comparison with positive sentence endings, suggesting a positive interpretation bias. In contrast, the high-anxious group evidenced equivalent P600 magnitude for negative and positive sentence endings, suggesting a lack of positive interpretation bias. Similar, but less reliable results emerged in earlier time windows, that is, 200-500 ms poststimulus. Reaction time, occurring around 900 ms poststimulus, failed to show a reliable interpretation bias. Results suggest that ERPs can detect interpretation biases in social anxiety before the emission of behavioral responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Olfactory and auditory event-related potentials in Huntington's disease.

The influence of Huntington's disease (HD) on the olfactory event-related potential (OERP), an electrophysiological measure of olfactory information processing, has not been reported to date. In the present study, olfactory and auditory event-related potentials (ERPs) were recorded monopolarly from Fz, Cz, and Pz electrode sites in 8 patients with HD and 8 age- and gender-matched control participants. Results demonstrated that individuals with HD were delayed compared with controls on the P3 component of the OERP (p     

The effects of immediate stimulus repetition on reaction time and event-related potentials in tasks of different complexity.

Examined the effect of immediate stimulus repetition in lexical decision, face recognition, letter search, face/nonface discrimination, and word/number discrimination tasks using reaction time (RT), accuracy, and event-related brain potential (ERP) measures. Repetition facilitated performance in all tasks and for all stimulus types. However, ERPs were strongly affected by repetition only in lexical decision, face recognition, and letter search, when relatively long stimulus analysis and decision making processes were required. The ERP repetition effect consisted of a significant increase in P300 amplitude and a shortening of its latency. Repetition also resulted in the attenuation of a negative component that was tentatively identified as N400. These results suggest that immediate repetition facilitates stimulus identification and eliminates the need for stimulus analysis processes including access to semantic memory while making categorical decisions. While both factors affected RT, ERPs were modulated primarily by the elimination of the need to access to semantic memory and by the consequent speeding of categorical decision processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociating the effects of automatic activation and explicit expectancy on reaction times in a simple associative learning task.

After repeated associations between two events, E1 and E2, responses to E2 can be facilitated either because participants consciously expect E2 to occur after E1 or because E1 automatically activates the response to E2, or because of both. In this article, the authors report on 4 experiments designed to pit the influence of these 2 factors against each other. The authors found that the fastest responses to a target in a reaction time paradigm occurred when automatic activation was highest and conscious expectancy lowest. These results, when considered together with previous findings indicating that, under most conditions, the relation between expectancy and reaction times is in the opposite direction, are indicative of a reversed association-an interaction pattern that J. C. Dunn and K. Kirsner (1988) demonstrated to be the only one that unambiguously points to the involvement of independent processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infant attention and visual preferences: Converging evidence from behavior, event-related potentials, and cortical source localization.

In this study, we had 3 major goals. The 1st goal was to establish a link between behavioral and event-related potential (ERP) measures of infant attention and recognition memory. To assess the distribution of infant visual preferences throughout ERP testing, we designed a new experimental procedure that embeds a behavioral measure (paired comparison trials) in the modified-oddball ERP procedure. The 2nd goal was to measure infant ERPs during the paired comparison trials. Independent component analysis (ICA) was used to identify and to remove eye-movement components from the electroencephalographic data, thus allowing for the analysis of ERP components during paired comparison trials. The 3rd goal was to localize the cortical sources of infant visual preferences. Equivalent current dipole analysis was performed on the ICA components related to experimental events. Infants who demonstrated novelty preferences in paired comparison trials demonstrated greater amplitude Negative central ERP components across tasks than infants who did not demonstrate novelty preferences. Visual preference also interacted with attention and stimulus type. The cortical sources of infant visual preferences were localized to inferior and superior prefrontal cortex and to the anterior cingulate cortex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual event-related potentials in schizotypal personality disorder and schizophrenia.

Schizophrenia (SZ) occurs among a spectrum of disorders with similar characteristics, including schizotypal personality disorder (SPD). Visual processing disturbances have been reported in both disorders, but it is not yet clear which processes are disturbed in both SZ and SPD, suggestive of a common endophenotype, and which appear only in SZ. In order to address this question, the authors evaluated visual event-related potentials (ERPs) elicited during a line-orientation discrimination task in control, SPD, and SZ participants. Visual ERPs allow specification of both the time course and physiological correlates of visual perception and cognition. SZ patients had smaller P100 and P300a amplitudes and prolonged P300b latency compared to the control group. SZ patients also had smaller N160, N200, P300a, and P300b amplitudes compared to the SPD group. SPD participants did not differ from control participants on any ERP measure. These data documented pervasive abnormalities in visual perception and attention in SZ but not in SPD, suggesting that these visual ERP disturbances may not represent a common endophenotype. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Do's and don'ts with lateralized event-related brain potentials.

K. Wiegand and E. Wascher (2005) used the lateralized readiness potential (LRP) to investigate the mechanisms underlying spatial stimulus-response (S-R) correspondence. The authors compared spatial S-R correspondence effects obtained with horizontal and vertical S-R arrangements. In some relevant previous investigations on spatial S-R correspondence with the LRP, researchers preferred to use the vertical S-R layout to circumvent methodological issues related to the LRP and horizontal S-R layouts. K. Wiegand and E. Wascher (2005) do not address these complications, and they make comparisons between electroencephalographic (EEG) data collected with horizontal and vertical S-R arrangements that do not take into account the limitations inherent to the LRP derivation. This methodological weakness renders unsound the neurophysiological support for their views on the nature of spatial S-R compatibility effects. In this article, the author discusses the limitations and possibilities of lateralized event-related potentials (ERPs) in the investigation of spatial S-R correspondence effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory event-related potentials in Parkinson's disease

We studied 49 patients with Parkinson's disease (PD) by a neuropsychological battery examining the temporo-spatial orientation, short-term memory, comprehension, non-verbal intelligence, long-term memory and anomia and the Auditory Event-Related Potentials. In the patients the latencies of the N100 and N200 waves were prolonged and the amplitude of the P300 wave was reduced compared with controls. No difference was found in the ERP of patients with and without cognitive deficits. Equally, no correlation was found between the ERP, the cognitive impairment, the length or the severity of the disease evaluated by Hoehn-Yahr's and Webster's scales.     

Effects of performance expectancy and self-focused attention on social interaction.

Investigated the impact of performance expectancies and self-focused attention on social performance in mixed-sex dyads of 48 undergraduate men with self-reported moderate social anxiety on a modified Social Avoidance and Distress Scale. Ss were divided into 2 groups on the basis of their high or low performance expectancies. Ss were asked to respond to several self-report questionnaires before and after making a telephone call lasting 4–5 min to a female confederate for the purpose of getting acquainted. Results show that half of the Ss in each expectancy group performed in the presence of a self-focusing stimulus (video-camera). When anxiety level was controlled for, focus of attention alone had a very limited effect on performance. Expectancy had a significant influence on social performance, but only if Ss were self-focused. Thus confident Ss were rated by judges as more socially skilled than were doubtful Ss, but only when the camera was present. The interaction between these variables parallels previous research by C. S. Carver et al (see record 1980-32489-001) and Carver and M. F. Scheier (see record 1980-25774-001) and supports the self-regulation model of Carver and Scheier (1983). (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)