Is a stimulus conveying task-relevant information a sufficient condition to elicit a stimulus-preceding negativity?

Movement-preceding and stimulus-preceding negativities were recorded when a movement was followed by one of three informative visual stimuli. The meaning of the visual stimulus alternated between (a) conveying a task-relevant instruction about a subsequent time production task and (b) providing feedback (knowledge of results) about performance on the current time production task. In a control condition, premovement and postmovement scalp potentials were recorded when subjects made the same movements but in a voluntary, self-paced manner. Under all conditions, movements were preceded by a movement-preceding negativity, and neither the amplitude nor the lateral asymmetry of this negativity was affected by the subsequent presentation of either kind of informative stimulus. When the movement was followed by a stimulus conveying knowledge of results, the negativity in the postmovement epoch was enhanced, but this enhancement was not evident in epochs preceding instruction stimuli. We conclude that not all task relevant stimuli elicit a stimulus-preceding negativity, and we provide a functional interpretation of this negativity in terms of emotional anticipation and the contingency of the stimulus on a previous event.     

Effects of reward and stimulus modality on stimulus-preceding negativity

The present study aimed to investigate the effect of reward and stimulus modality of feedback stimuli on the stimulus-preceding negativity. A time estimation task was performed, and (a) the motivational level (reward and no-reward) and (b) the stimulus modality (auditory and visual) of feedback stimuli were manipulated. The results demonstrated that the stimulus-preceding negativity was larger in the reward than in the no-reward condition, especially at the right frontal and the left occipito-temporal areas. Moreover, the stimulus-preceding negativity prior to visual feedback stimuli was larger over the occipital areas than in the auditory condition. In contrast, at the prefrontal areas, the amplitude prior to auditory feedback stimuli was larger than in the visual condition. Our results revealed that the prefeedback stimulus-preceding negativity was independently influenced by stimulus modality and motivation.     

Event-related potential correlates of non-motor anticipation.

A slow negative shift called "stimulus-preceding negativity" (SPN) has been observed preceding feedback. The aim of the present study is to investigate whether the SPN is related to perceptual or conceptual anticipation. Event-related potentials (ERPs) were recorded in an S1-S2-S3 sequence with intervals of 3 s. S1 was an auditory warning signal; the task stimulus presented at S2 consisted of two digits on which subjects (n = 8) performed an arithmetic task. They had to match their solution with a probe stimulus presented at S3. Perceptual anticipation was manipulated by varying the discriminability of S2 (intact vs. degraded). Conceptual anticipation was manipulated by varying the amount of information processing required at S2 (easy vs. difficult arithmetic). Motor preparation was varied by requiring a speeded versus a delayed response. No negativity was found before the task stimulus (S2), whereas the probe stimulus (S3) was always preceded by a negative shift. The amplitude of this negative shift was larger under the speed than under the delayed instruction. Its amplitude showed a left-hemisphere preponderance and was larger for the difficult than for the easy condition. ERPs preceding task stimuli seem to reflect functionally different processes from ERPs preceding probe and feedback stimuli. The difference is explained in terms of motivational factors that come into play with feedback and probably play a role in the anticipation of the probe stimulus.     

Activation of insular cortex and subcortical regions related to feedback stimuli in a time estimation task: an fMRI study

We used functional magnetic resonance imaging to investigate brain activity related to motivational function of informative feedback stimuli in a time estimation task. In that task, subjects pressed a button as a response 3 s after a cue stimulus; a visual feedback stimulus was presented 2 s after the response. In a true feedback condition, subjects received true information (informative feedback) about their time-estimation performance. In the false feedback condition, the same visual signs were used, but they were presented randomly. Therefore, they were not related to actual performance. In the 20 subjects examined, higher hemodynamic responses were identified in the insular cortex, the thalamus, and the striatum by comparing the true feedback condition to the false feedback condition. The time estimation performance and subjective score on motivation were also markedly higher in the true feedback condition. The anterior insular cortex and striatal regions are known to be involved in motivational and reward processing. Therefore, the hemodynamic responses observed in this study suggest that the motivational function of the feedback information is a crucial factor for behavioral learning; it is considered that the informative feedback might serve as an implicit reward for humans.     

Cortical potentials during the gap prior to express saccades and fast regular saccades

When a temporal gap is introduced between the offset of the central fixation point and the appearance of a new target, saccadic reaction time is reduced (gap effect) and a special population of extremely fast saccades occurs (express saccades). It has been hypothesized that the gap triggers a readiness signal, which is responsible for the reduced saccadic reaction times. Here we recorded event-related potentials during the gap to in vestigate the central processes associated with the gener ation of fast regular saccades and express saccades. Prior to the execution of fast regular saccades, subjects pro duced a slow negative shift, with a maximum at frontal and central channels that started 40 ms after fixation offset. This widespread negativity is similar to a readiness potential. Anticipatory saccades were preceded by an increased frontal and parietal negativity. Prior to express saccades, a frontal negativity was observed, which started 135 ms after the disappearance of the fixation point. It is assumed that the frontal negativity prior to express saccades corresponds to the fixation-disengagement dis charge described in the frontal eye field of monkeys. Therefore, we hypothesize that fast regular saccades are the result of an increased readiness signal, while express saccades are the result of specific preparatory processes.     

Genetic variation in dopamine moderates neural response during reward anticipation and delivery: evidence from event-related potentials

Neuroimaging studies have found moderating effects of dopamine genes during both the anticipation and delivery of rewards, particularly the catechol-O-methyltransferase (COMT) genotype. Event-related potential studies, meanwhile, have focused on the stimulus-preceding negativity (SPN) and the feedback negativity (FN) during reward anticipation and delivery, respectively. In anticipation of uncertain outcomes, we observed an increased SPN among Met homozygotes. We also observed an increased FN among Met homozygotes in response to outcome delivery, an effect that was driven primarily by an increased response to monetary gains. The COMT genotype moderates event-related potential responses during both the anticipation and delivery of uncertain reward, suggesting that the SPN and FN are sensitive to dopaminergically mediated and reward-related neural activity.     

Response complexity and precue interval effects on the lateralized readiness potential

Fundamental properties of an important new tool in cognitive electrophysiology, the lateralized readiness potential (LRP), were examined in two experiments. Experiment 1 resolved an apparent inconsistency in the literature by demonstrating that this response-specific lateralization is larger preceding complex then preceding simple finger movements. In Experiment 2, the foveally presented precue, which indicated hand of response, preceded the go/no-go stimulus by 0, 100, 300, or 1,400 ms. Analyses of LRP latency indicated that hand-specific preparation began earlier with longer foreperiods but was temporally linked to the reaction stimulus as well as the precue. Although the degree of lateralization did not predict reaction speed in either study, a nonlateralized, response-locked negativity was larger prior to faster reactions.     

The role of the right anterior insular cortex in the right hemisphere preponderance of stimulus-preceding negativity (SPN): An fMRI study

The stimulus-preceding negativity (SPN) is an event-related potential that reflects emotional and perceptual anticipation. The SPN is characterized by a right hemisphere preponderance in amplitude, and previous studies suggest that activity in the insular cortex might contribute to the amplitude of the SPN. Although the insula might contribute to the SPN's occurrence, the exact role of the insula in the pattern of SPN right hemisphere dominance remains unclear. In the present study, we manipulated task difficulty and brain activation was measured using event-related fMRI, to examine the relationship between insula functioning and the right hemisphere preponderance of the SPN. Twenty-three participants performed a time estimation task, in which they had to press a button when they thought a predetermined time had elapsed. Three seconds after pressing the button, a feedback stimulus was presented, informing subjects as to whether their response was correct, too early, or too late. There were four experimental conditions: easy, moderate, difficult, and no feedback. The fMRI results showed significantly increased activation in the bilateral insular cortex during the pre-feedback anticipation phase, in which the subjects prepare to pay attention to the occurrence of feedback stimuli. In addition, in the Difficult–Easy and Difficult–Moderate contrasts, significantly increased activations of the right anterior insula were demonstrated, suggesting the possibility that this area does underlie the SPN right hemisphere preponderance. Because the right anterior insula is related to awareness of viscerosensory information, the SPN right hemisphere preponderance might itself be related to the awareness of interoceptive information that precedes feedback stimuli.     

The effect of interpersonal competition on monitoring internal and external error feedback

The present study examined the effect of the social context on early emotional appraisal of performance errors and negative feedback reflected by the error‐related negativity (ERN), feedback‐related negativity (FRN), and P300. Participants performed a probabilistic learning task in which they received valid and invalid performance feedback. During one half of the task they were led to believe that they were competing online against another participant. As expected, the ERN following response errors was enhanced in the competition compared to the neutral condition. The FRN was more negative following negative compared to positive feedback and valid compared to invalid feedback, but only during competition. The P300 was larger to false positive than false negative feedback, which was independent of the social context. In conclusion, ERN and FRN, but not P300, may be sensitive to affective distress elicited by expectation violations during social interaction.     

Effects of information and reward on stimulus-preceding negativity prior to feedback stimuli

The purpose of the present study was to investigate the effects of informational and motivational level of feedback stimuli on the stimulus-preceding negativity (SPN). In the time estimation task, in which a visual stimulus was presented 3 s after a voluntary movement, (a) the information level (high information and low information) and (b) the motivation level (reward and no-reward) for feedback stimuli were manipulated. Under the high-information condition, subjects received feedback information about (1) correctness (correct or incorrect), (2) direction of error (under- or overestimate), and (3) degree of accuracy (accurate or less accurate) of their time estimation. In the low-information condition, however, they received information about the correctness only. In the reward condition, they received a monetary reward for accurate time estimations but received nothing in the no-reward condition. The results demonstrated a significant interaction of information by motivation level, showing that the SPN amplitude under the reward/high-information was larger than that in the no-reward/high-information condition. The results are discussed in terms of emotional anticipation, taking into consideration the result of self-report that subjects felt to be more motivated when they received precise information.     

ERP correlates of true and false recognition after different retention delays: stimulus- and response-related processes

Performance and electrophysiological correlates of true and false recognition were examined after short (40 s) and long (80 s) delays. True recognition showed no significant decrease after a long delay, whereas false recognition increased. Early frontal and parietal ERP old/new effects, considered as correlates of familiarity and recollection, were observed across delay for true recognition. No frontal effect occurred in the long delay for false recognition. This absence may arise from weakened memory traces preventing familiarity discrimination for LUREs. Response-related analysis revealed an error-related negativity (ERN) for true and false recognition, assuming that the effect reflects at least partly an internal misrepresentation of the correct response. The larger and topographically different ERNs for false recognition suggest an additional contribution of increased task demands and conditions of high response uncertainty.     

The Effects of Slow Cortical Potentials on Response Speed

The relationship between slow cortical potentials (SCPs) and response speed was investigated by training subjects to induce different cortical shifts by means of a biofeedback procedure. During two identical experimental sessions trials with visual feedback of the actual DC-shifts alternated with reaction time trials without feedback. In reaction time trials only the signal for the required change in polarity was provided. At the end of the signal interval an immediate button-press was required to stop a hissing noise. Two groups of 10 subjects each were investigated, one group receiving feed back from the left precentral recording(C₃) and the other from the right precentral recording (C₄). Results showed that subjects achieved control over their SCPs. At the end of the training period in the second session significant differences in SCPs between trials of the different required polarities were observed, during feedback trials as well as during reaction time trials without feedback. Subjects responded faster during trials in which a change toward more cortical negativity was required as compared to trials requiring less negativity.     

Can Echoic Memory Store Two Traces Simultaneously? A Study of Event-Related Brain Potentials

The mismatch negativity, a component of the event-related brain potential elicited by infrequent deviants in sequences of auditory stimuli, is presumably generated by an automatic mismatch process in a mechanism that compares the current stimulus to the trace of the previous one. The present study addressed the possible simultaneous existence of two such traces. Two equiprobable (45% each) frequent stimuli (“standards”), one of 600 Hz and the other of 700 Hz, were presented together with an infrequent (10%), “deviant” stimulus which was of differnet frequency in different blocks. These deviants elicited a mismatch negativity, though a smaller one than that obtained in corresponding blocks with only one standard stimulus. Two aspects of the present results from the blocks with two standard stimuli implicate two parallel stimulus traces in these blocks: 1) deviants elicited a mismatch negativity (MMN) of approximately the same amplitude when preceded by sequences of four identical standards as when preceded by sequences of four stimuli containing both standards; 2) in contrast to the one-standard condition, the magnitude of stimulus deviance did not affect the MMN component elicited by the different deviants.     

Shifting attention between global features and small details: an event-related potential study

In two experiments, large letters H or Z composed of small letters (also H or Z) were presented. Subjects had to make a two-choice motor response (e.g. H — left key, Z — right key). A cue presented 500 ms before the letter indicated which level (global or local) was relevant. In Experiment I, a third letter (T) sometimes appeared either at the cued or the non-cued level; in the former case, subjects had to shift their attention and to respond to stimulus features located at the non-cued level. The interference effect (RT delay in response to incongruent stimuli as compared to congruent ones) was larger when the local, rather than global, level was cued. A slow anterior negativity preceding globally-cued stimuli and shorter N1 and P2 ERP component latencies to these stimuli indicated better preparation for processing of global, as compared to local, stimulus features. The shift from local to global focus yielded a larger increase of RT, error rate, and of the P600 latency than the global-to-local shift. The P600 latency changes were parallel to those of RT. In Experiment II, the attentional shift was provoked by stimulus color; red-colored letters meant that the cue was invalid, and thus, subjects had to respond to the non-cued level. Neither the interference nor the attentional shift demonstrated any asymmetry between the global and local levels. ERPs also did not differ substantially after local and global cues. In the condition demanding a shift of focus (invalid cue, incongruent letter), a positive deflection of the lateralized readiness potential indicated the activation of the wrong response channel. The large RT increment in this condition was not accompanied by an increase of the P600 latency. Two possible mechanisms of attentional shift may be proposed, the first related to perceptual processes (e.g. an additional visual search), and the second, to the competition between two response intentions.     

Topographic measures of cerebral activity during reading of text at fast- and slow-paced rates

Summary Eight college level readers were given short paragraphs for reading, presented on a computer terminal in units of 2 or 3 words at a time. Two conditions were presented, a fast reading session with an inter-stimulus interval (ISI) of 1.1 seconds, and a slower session with an ISI of 1.2 seconds. EEG and ERP measures were obtained. ERP findings revealed a late central-posterior negativity which was sensitive to the effect of varying ISI by showing shorter latencies, of about 110 msec, to the smaller interval. An earlier component complex consisting of a bi-temporal-occipital negativity and frontal positivity was observed between 155 and 175 msec. This component was not observed to be sensitive to variation of ISI. Analysis of the unaveraged EEG activity by FFT and absolute power measures revealed that the activity was primarily slow wave (0-7.5 HZ), and right-sided. Findings suggested that the brain functions as an integrated whole during reading, activating a diffuse set of neural generators.     

Effect of positive and negative emotion on stimulus-preceding negativity prior to feedback stimuli

Stimulus-preceding negativity (SPN) was recorded to investigate the effect of positive and negative emotion on the SPN preceding feedback stimuli. In the time-estimation task in which an acoustic stimulus was presented 3 s after a voluntary movement, (1) the negative valence (aversive band noise and pure tone) and (2) the positive valence (reward and no-reward) of feedback stimuli were manipulated. During noise conditions, participants received the band noise as a feedback stimulus except when their time estimations were accurate. They received a monetary reward for accurate time estimations under the reward conditions. The prefeedback SPN was larger under reward than no-reward conditions. In addition, the prefeedback SPN in the noise condition was larger compared with the pure tone condition. Our results appear to suggest that emotional anticipation is important in eliciting the prefeedback SPN.     

Temporal course of emotional negativity bias: an ERP study

There is considerable evidence that people are especially sensitive to emotionally negative materials. However, the temporal course of the negativity bias is still unclear. To address this issue, we observed the changes of P2, late positive components (LPC) and lateralized readiness potential (LRP) under positive, negative and neutral conditions, with International Affective Picture System (IAPS) pictures as emotional stimuli. We found that the amplitude of P2 in the negative block was significantly larger than that in the positive block, indicating that the attentional negativity bias occured very early in emotion perception. The LPC amplitude evoked by negative pictures was larger than that by positive and neutral pictures, suggesting that the negativity bias also occurred in a later evaluation stage of emotion processing. The response-locked LRP interval was shortest in the block of negative pictures, indicating that the negative contents elicited a reaction priming effect. Above all, this research showed that emotional negativity bias could occur in several temporal stages distinguished by attention, evaluation and reaction readiness periods.     

Monitoring retrieval from long-term memory by slow event-related brain potentials

Slow event-related brain potentials of nine subjects were recorded in an experimentally controlled long-term memory retrieval task (the Fan paradigm) from electrode sites F3, Fz, F4, Cz, P3, Pz, and P4. In all retrieval conditions, a very pronounced DC-like negative potential appeared over the left frontal cortex. This negativity was switched on with the presentation of the probe stimuli and prevailed in some conditions throughout the total recording epoch of 14 s. Particular retrieval conditions became manifest in distinct slow wave effects. The amplitude of a bilaterally distributed frontal negative slow wave increased when a more diversified associative structure had to be searched. The amplitude of another negative slow wave, which peaked bilaterally over parietal areas, was affected by the type of concepts that had to be retrieved. The amplitude was larger with general concepts (category labels) and smaller with specific concepts (category exemplars). These results suggest that distinct strategies are invoked when subjects are required to draw conclusions about different contents stored permanently in an associative network.     

Short-Term Habituation and Dishabituation of the Mismatch Negativity of the ERP

Standard tones of 1000 Hz and deviant tones of 1250 Hz were presented in random order, 1 stimulus/second. The probabilities of the standards and deviants were 90% and 10%, respectively. In one condition the subject counted the deviant stimuli and in the other condition he/she read a comic book. ERPs were separately averaged to 1) the standard preceding the deviant, 2) the “first deviant” preceded by at least 4 standards, 3) the “second deviant” (an occasional deviant immediately following the “first deviant”), 4) the first and 5) the second standard following the “first deviant,” 6) the first and 7) the second standard following the “second deviant.” It was found that the mismatch negativity evoked in both conditions by the first deviant was considerably larger than to the second deviant. Also the first standard following the first deviant evoked the mismatch negativity. The results are discussed in terms of parallel neuronal models of the stimuli as reflected by the mismatch negativity.     

Context dependence of the event-related brain potential associated with reward and punishment

The error-related negativity (ERN) is an event-related brain potential elicited by error commission and by presentation of feedback stimuli indicating incorrect performance. In this study, the authors report two experiments in which participants tried to learn to select between response options by trial and error, using feedback stimuli indicating monetary gains and losses. The results demonstrate that the amplitude of the ERN is determined by the value of the eliciting outcome relative to the range of outcomes possible, rather than by the objective value of the outcome. This result is discussed in terms of a recent theory that holds that the ERN reflects a reward prediction error signal associated with a neural system for reinforcement learning.