Auditory development between 7 and 11 years: an event-related potential (ERP) study

Background

There is considerable uncertainty about the time-course of central auditory maturation. On some indices, children appear to have adult-like competence by school age, whereas for other measures development follows a protracted course.

Methodology

We studied auditory development using auditory event-related potentials (ERPs) elicited by tones in 105 children on two occasions two years apart. Just over half of the children were 7 years initially and 9 years at follow-up, whereas the remainder were 9 years initially and 11 years at follow-up. We used conventional analysis of peaks in the auditory ERP, independent component analysis, and time-frequency analysis.

Principal Findings

We demonstrated maturational changes in the auditory ERP between 7 and 11 years, both using conventional peak measurements, and time-frequency analysis. The developmental trajectory was different for temporal vs. fronto-central electrode sites. Temporal electrode sites showed strong lateralisation of responses and no increase of low-frequency phase-resetting with age, whereas responses recorded from fronto-central electrode sites were not lateralised and showed progressive change with age. Fronto-central vs. temporal electrode sites also mapped onto independent components with differently oriented dipole sources in auditory cortex. A global measure of waveform shape proved to be the most effective method for distinguishing age bands.

Conclusions/Significance

The results supported the idea that different cortical regions mature at different rates. The ICC measure is proposed as the best measure of ‘auditory ERP age’.     

Effect of empathy trait on attention to faces: an event-related potential (ERP) study

Background

Empathy is deeply linked with the ability to adapt to human social environments. The present study investigated the relationship between the empathy trait and attention elicited by discriminating facial expressions.

Methods

Event-related potentials were measured while 32 participants (17 men and 15 women) discriminated facial expressions (happy or angry) and colors of flowers (yellow or purple) under an oddball paradigm. The empathy trait of participants was measured using the Interpersonal Reactivity Index (Davis, 1980).

Results

The empathy trait correlated positively with both the early portion (300 to 600 ms after stimulus onset) and late portion (600 to 800 ms after stimulus onset) of late positive potential (LPP) amplitude elicited by faces, but not with LPP elicited by flowers.

Conclusions

This result suggests that, compared to people with low empathy, people with high empathy pay more attention when discriminating facial expressions. The present study suggests that differences exist in methods of adapting to social environments between people with high and low empathy.     

Error processing and response inhibition in excessive computer game players: an event-related potential study

Excessive computer gaming has recently been proposed as a possible pathological illness. However, research on this topic is still in its infancy and underlying neurobiological mechanisms have not yet been identified. The determination of underlying mechanisms of excessive gaming might be useful for the identification of those at risk, a better understanding of the behavior and the development of interventions. Excessive gaming has been often compared with pathological gambling and substance use disorder. Both disorders are characterized by high levels of impulsivity, which incorporates deficits in error processing and response inhibition. The present study aimed to investigate error processing and response inhibition in excessive gamers and controls using a Go/NoGo paradigm combined with event-related potential recordings. Results indicated that excessive gamers show reduced error-related negativity amplitudes in response to incorrect trials relative to correct trials, implying poor error processing in this population. Furthermore, excessive gamers display higher levels of self-reported impulsivity as well as more impulsive responding as reflected by less behavioral inhibition on the Go/NoGo task. The present study indicates that excessive gaming partly parallels impulse control and substance use disorders regarding impulsivity measured on the self-reported, behavioral and electrophysiological level. Although the present study does not allow drawing firm conclusions on causality, it might be that trait impulsivity, poor error processing and diminished behavioral response inhibition underlie the excessive gaming patterns observed in certain individuals. They might be less sensitive to negative consequences of gaming and therefore continue their behavior despite adverse consequences.     

Visual cognitive dysfunction in depression: an event-related potential study

The P3(00) event-related potentials (ERPs) elicited by visual stimuli in two visual tasks were assessed in depressed patients (12 patients with major depression and 11 patients with bipolar disorder) and compared with those of 20 age-matched normal controls. At remission, the ERPs from 18 of the depressed patients were again recorded. The visual oddball (VO) paradigm presented both target and standard visual stimuli and the simple visual (SV) paradigm presented a target but no standard visual stimulus. Subjects performed the VO task significantly less accurately than the SV task, as reflected by the behavioral measures (reaction-time and task accuracy). Depressed patients of the bipolar group showed longer P3 peak latency for the VO task and no change in P3 amplitude. No significant differences were found in any other ERP component between the groups. During remission, slowing RTs and reduced P3 peak latencies were observed for both major depression and bipolar disorder groups. Thus, the P3 ERP may be an index of the contribution of the slowed central processing to psychomotor retardation in clinically homogenous samples of depressive patients performing an appropriately demanding task.     

Neuroelectric evidence for cognitive association formation: an event-related potential investigation

Although many types of learning require associations to be formed, little is known about the brain mechanisms engaged in association formation. In the present study, we measured event-related potentials (ERPs) while participants studied pairs of semantically related words, with each word of a pair presented sequentially. To narrow in on the associative component of the signal, the ERP difference between the first and second words of a pair (Word2-Word1) was derived separately for subsequently recalled and subsequently not-recalled pairs. When the resulting difference waveforms were contrasted, a parietal positivity was observed for subsequently recalled pairs around 460 ms after the word presentation onset, followed by a positive slow wave that lasted until around 845 ms. Together these results suggest that associations formed between semantically related words are correlated with a specific neural signature that is reflected in scalp recordings over the parietal region.     

Vasopressin and cognitive processes: Two event-related potential studies

Two experiments studied the influence of arginine-vasopressin (AVP) on cognitive processes by means of an electrophysiological measure, the late positive complex (LPC) of the event-related potential. The LPC varies systematically with cognitive processes. The classical oddball paradigm and an incidental memory task (structural encoding of emotional adjectives) were used. The two studies differed only in the dose of AVP (study 1: three time nasal application of 10 IU AVP; study 2: 20 IU). In study 1, AVP intake enhanced memory performance. The LPC elicited by oddball stimuli was not influenced by AVP, neither when compared before and after intake nor when compared to placebo treatment. However, specific influences of AVP on the LPC elicited during the structural encoding task were observed. In both studies, AVP intake resulted in a marked change of the scalp distribution of the P3 component, which is a prominent part of the LPC. Furthermore, subjects treated with the lower dose of AVP showed a more positive P3 component on emotional (negative and positive) adjectives, when compared to neutral ones. The results suggest that vasopressin influences the central nervous processing of the emotional content of stimuli.     

Dissociable influences of reward and punishment on adaptive cognitive control

To invest effort into any cognitive task, people must be sufficiently motivated. Whereas prior research has focused primarily on how the cognitive control required to complete these tasks is motivated by the potential rewards for success, it is also known that control investment can be equally motivated by the potential negative consequence for failure. Previous theoretical and experimental work has yet to examine how positive and negative incentives differentially influence the manner and intensity with which people allocate control. Here, we develop and test a normative model of control allocation under conditions of varying positive and negative performance incentives. Our model predicts, and our empirical findings confirm, that rewards for success and punishment for failure should differentially influence adjustments to the evidence accumulation rate versus response threshold, respectively. This dissociation further enabled us to infer how motivated a given person was by the consequences of success versus failure.     

Analysis of event-related potentials (ERP) by damped sinusoids

Several researchers propose that event-related potentials (ERPs) can be explained by a superposition of transient oscillations at certain frequency bands in response to external or internal events. The transient nature of the ERP is more suitable to be modelled as a sum of damped sinusoids. These damped sinusoids can be completely characterized by four sets of parameters, namely the amplitude, the damping coefficient, the phase and the frequency. The Prony method is used to estimate these parameters. In this study, the long-latency auditory-evoked potentials (AEP) and the auditory oddball responses (P300) of 10 healthy subjects are analysed by this method. It is shown that the original waveforms can be reconstructed by summing a small number of damped sinusoids. This allows for a parsimonious representation of the ERPs. Furthermore, the method shows that the oddball target responses contain higher amplitude, slower delta and slower damped theta components than those of the AEPs. With this technique, we show that the differentiation of sensory and cognitive potentials are not inherent in their overall frequency content but in their frequency components at certain bands. Received: 6 October 1997 / Accepted in revised form: 26 February 1998     

Dissociable processes of cognitive control during error and non-error conflicts: a study of the stop signal task

Background

Conflict detection and subsequent behavioral adjustment are critical to daily life, and how this process is controlled has been increasingly of interest. A medial cortical region which includes the anterior cingulate cortex (ACC) has been theorized to act as a conflict detector that can direct prefrontal activity for behavioral adjustments. This conflict monitoring hypothesis was supported by many imaging studies of the Stroop task, with a focus on non-error processes. Here we sought to examine whether this circuit could be generalized to the stop signal task (SST), another behavioral paradigm widely used to study cognitive control. In particular, with a procedure to elicit errors in the SST, we examined whether error and non-error control were mediated by the same pathways.

Methodology/Principal Findings

In functional magnetic resonance imaging of 60 healthy adults, we demonstrated that the medial cortical activity during stop success (SS) as compared to go success (G) trials is correlated with increased prefrontal activity in post-stop SS as compared to post-go SS trials, though this correlation was not specific to the medial cortical region. Furthermore, thalamic and insular rather than medial cortical activation during stop error (SE) as compared to G trials correlated with increased prefrontal activity in post-stop SS as compared to post-go SS trials.

Conclusions/Significance

Taken together, these new findings challenge a specific role of the ACC and support distinct pathways for error and non-error conflict processing in cognitive control.     

Auditory selective attention in middle-aged and elderly subjects: an event-related brain potential study

Reaction times (RTs) and event-related brain potentials (ERPs) were recorded in middle-aged (MA) and elderly (ELD) subjects performing an auditory selective attention task. Subjets attended to tone bursts of a specified pitch and ear of delivery and responded to occasional longer duration target tones (75 vs. 25 msec). Infrequent novel stimuli (computer synthesized sounds and digitized environmental noises) were also included in the stimulus sequence.No significant age-related differences were found in the speed or accuracy of target detection. However, in both groups, RTs were delayed (by more than 300 msec) to targets that followed novel sounds. The prolongation was greater following novel sounds in the attended ear, particularly in the ELD group.The effects of selective attention on ERPs to standard tones were isolated as negative difference waves (Nds) by subtracting ERPs to non-attended stimuli from ERPs to the same signals when attended. Nds had similar amplitudes, latencies of onset (60 msec), and distributions in ELD and MA groups. In both groups, Nd waves were more prominent following right ear stimulation, reflecting possible hemispheric asymmetries of generators in posterior temporal regions.The mismatch negativity (MMN) was isolated by subtracting ERPs to standard tones from ERPs to deviant stimuli. MMN amplitudes were reduced in the ELD group. There was also a significant change in MMN distribution with age: the MMN was larger over the right hemisphere for MA subjects but larger over the left for ELD subjects. Elderly subjects showed a trend toward smaller P3 amplitudes and delayed P3 latencies, but group differences did not reach statistical significance. ERPs to novel sounds were characterized by centrally distributed N2 and P3a components. Although the novel P3a was enhanced with attention, no novel Nd waves could be isolated. This suggests that novel sounds fell outside the focus of attention.     

Dissociation of category versus item priming in face processing: an event-related potential study

The underlying specificity of visual object categorization and discrimination can be elucidated by studying different types of repetition priming. Here we focused on this issue in face processing. We investigated category priming (i.e. the prime and target stimuli represent different exemplars of the same object category) and item priming (i.e. the prime and target stimuli are exactly the same image), using an immediate repetition paradigm. Twenty-three subjects were asked to respond as fast and accurately as possible to categorize whether the target stimulus was a face or a building image, but to ignore the prime stimulus. We recorded event-related potentials (ERPs) and reaction times (RTs) simultaneously. The RT data showed significant effects of category priming in both face trials and building trials, as well as a significant effect of item priming in face trials. With respect to the ERPs, in face trials, no priming effect was observed at the P100 stage, whereas a category priming effect emerged at the N170 stage, and an item priming effect at the P200 stage. In contrast, in building trials, priming effects occurred already at the P100 stage. Our results indicated that distinct neural mechanisms underlie separable kinds of immediate repetition priming in face processing.     

Inter-individual relationships in empathic traits and feedback-related fronto-central brain activity: an event-related potential study

Background

Neuroimaging studies continue to indicate the major role the anterior cingulate cortex (ACC) plays in processing empathic responses. Error-related negativity (ERN), an event-related potential (ERP) thought to arise from the ACC, has been found to correlate with scores for individual empathic personality. This study investigated the relationship between empathic personality traits and the amplitude of feedback-related negativity (FRN), an ERP sourced from the ACC and similar to the ERN, using a task involving feedback of monetary gains or losses.

Methods

Sixteen healthy participants answered an empathy trait questionnaire and performed a gambling task to elicit FRN. Because FRN amplitude is thought to be associated with attention, motivation, emotional state, and anxiety trait, we performed a partial correlation analysis between the empathic trait score and FRN amplitude while controlling for variables.

Results

In partial correlation analysis, FRN amplitude was significantly inversely correlated with scores for personal distress and marginally correlated with scores for empathic concern and with total average score.

Discussion

The study revealed for the first time an association between FRN and emotional empathic traits, after controlling for variables that can affect FRN amplitude. However, we also found a reversed directional correlation contrary to our expectations. This fronto-central brain activity may be associated with empathic properties via dopaminergic neuronal function. Future study using these electric potentials as experimental tools is expected to help elucidate the neurological mechanism of empathy.

     

On the tip of the tongue: an event-related fMRI study of semantic retrieval failure and cognitive conflict.

The tip of the tongue (TOT) state refers to a temporary inaccessibility of information that one is sure exists in long-term memory and is on the verge of recovering. Using event-related fMRI, we assessed the neural correlates of this semantic retrieval failure to determine whether the anterior cingulate-lateral prefrontal neural circuit posited to mediate conflict resolution is engaged during metacognitive conflicts that arise during the TOT. Results revealed that, relative to successful retrieval or unsuccessful retrieval not accompanied by a TOT, retrieval failures accompanied by TOTs elicited a selective response in anterior cingulate-prefrontal cortices. During a TOT, cognitive control mechanisms may be recruited in attempts to resolve the conflict and retrieval failure that characterize this state.     

Hydrosols evaluation in pest control: insecticidal and settling inhibition potential against Myzus persicae (Sulzer)

The hydrosols are by‐products derived during the extraction of essential oils. Although essential oils have been widely evaluated for their insecticidal activities, the possible use of hydrosols in pest control has been almost unknown. The effects of the hydrosols of Origanum majorana (marjoram), Mentha pulegium (pennyroyal), and Melissa officinalis (lemon balm) on the survival and settling behaviour of the aphid pest Myzus persicae were investigated. The hydrosols were isolated using Clevenger hydrodistillation (i) with conventional heating (HD) and (ii) assisted by microwaves (MWHD). GC‐MS analysis showed that the volatiles occurring in the hydrosols were similar between the two techniques. Hydrosols were assayed for possible settling inhibitory effects on M. persicae in Petri dishes (15 cm diameter). In each dish, a sprayed together with an unsprayed eggplant leaf piece was placed. An adult aphid <24 h old was released on the treated leaf and its path length was recorded during the initial 10 min. Then, its position (on the treated or untreated leaf) was recorded 10, 20, 30, 60 min and 24 h after spraying. M. officinalis HD hydrosol resulted in fourfold increase of the path length compared with the control (deionized water). The last observation (24 h) revealed that M. officinalis and M. pulegium HD hydrosols had the strongest inhibitory effect. Additionally, O. majorana hydrosols caused 10–15% aphid mortality after 24 h. In this study, the wider use of the MWHD technique is further supported as in addition to its well‐known advantages (i.e. shorter distillation time, less energy consumption), the effects of the hydrosols produced are comparable to those obtained by HD. Most importantly, the results clearly showed that the potential of hydrosols in pest control ought not to be ignored and should attract the interest of future studies.     

Aging,caffeine, and information processing: an event-related potential analysis

Structural and energetic processes in information processing were studied in young and elderly subjects. A visually focussed selective search task was used, in which subjects had to select relevant information, followed by controlled memory search processes to locate a target item. Caffeine was used to manipulate the energetic state of the subjects. During task performance event-related potentials (ERPs) and reaction time (RT) were recorded.Subjects were 15 young and 15 elderly healthy, non-smoking, moderate caffeine consumers (250–600 mg/day). Before the experimental sessions they abstained from caffeine for ≥12 h. In the experiment subjects received 250 mg caffeine or placebo dissolved in decaffeinated coffee.RT data seem to indicate that aging effects are at least partly due to a shift in the speed-accuracy trade-off. ERP results provide evidence for decreased levels of energy resources in the elderly. The identification of relevant information and stimulus evaluation processes were delayed in the elderly, suggesting an additional effect of aging on structural processes. Caffeine improved performance and increased the amplitude of the N1, N2b, and P3b, in both young and old subjects. These results suggest that caffeine makes more energy resources available for task performance. The effects of aging on P3b latency were counteracted by caffeine. Other caffeine effects did not differ significantly between young and elderly subjects.     

Effects of cue information on response production and inhibition measured by event-related potentials

The aim of this study was to investigate how information carried by a cue stimulus modulate event-related potentials (ERPs) to a subsequent target stimulus which either calls for an overt response (Go stimulus) or no response (Nogo stimulus). One of the cues predicted the likely appearance of the Go stimulus (Go cue) whereas the other cue predicted the likely appearance of the Nogo stimulus (Nogo cue). Our results showed that unpredicted Nogo stimuli elicited enlarged N200 component. This finding supports the notion that Nogo N200 reflects response inhibition processes, i.e., the amplitude of the N200 is a function of the difficulty of response inhibition. In other words, increased N200 to Nogo stimuli following Go cues might be related to increased efforts in activating the response inhibition system thereby interrupting preparations to respond.     

Spatial cueing,sensory gating and selective response preparation: an ERP study on visuo-spatial orienting

Event-related brain potentials (ERPs) were recorded in a visuo-spatial attention task where the position of an imperative stimulus was indicated either validly or invalidly by a central arrow (trial-by-trial cueing). Subjects had to perform choice RT tasks with the response being dependent either on the identity of the target stimulus or on its position. When target identity was relevant for response selection, validly cued stimuli elicited amplitude enhancements of the early, sensory-evoked P1 and N1 components at lateral posterior sites. The N1 validity effect was limited to scalp sites ipsilateral to the visual field of stimulus presentation. Although these effects were found only when the sensory discrimination task was considerably difficult, they are in line with models assuming that modulations of sensory-perceptual processing (“sensory gating”) are induced by spatial cueing. However, when target location was response-relevant, N1 amplitude enhancements were consistently elicited by invalidly cued letters.CNV and LRP measures indicated that the arrow elicited response-related processing in the cue-target interval. Such processes occurred even when the cue contained no information about an upcoming response. Two consecutive lateralization phases were distinguishable in the LRP, with experimentally induced response assignments becoming effective only during the second phase.     

Concentration effects of green odor on event-related potential (P300) and pleasantness

The effects of eight compounds, constituting the so-called "natural green odor", including leaf alcohol, on the event-related potential (P300) were investigated. In experiments with a series of single compounds, each of these eight compounds could be characterized by an overall change consisting predominantly of an increase, a decrease or no change in the amplitude of P300, whereas in experiments with a series of two-component mixtures, noticeable synergism could not be demonstrated, contrary to our expectation. Experiments with leaf alcohol (3Z-hexenol) performed at two concentrations showed a significantly different degree of pleasantness and an increase or decrease in the amplitude of P300 depending on their concentration, suggesting that concentration is important in odorant-presentation studies.