Voluntary acts are preceded by electrophysiological (RPs). With spontaneous acts involving no preplanning, the main negative RP shift begins at about200 ms. Control experiments, in which a skin stimulus was timed (S), helped evaluate each subject's error in reporting the clock times for awareness of any perceived event.

The present study applies a new method for investigating dynamic unconscious processes. The method consists of selection of words from patient interview and test protocols that in the clinicians' judgments capture the patients' conscious symptom experience and the hypothetical unconscious conflict related to the symptom, subliminal and supraliminal presentation of these words, signal analysis of event-related potentials obtained to the word presentations. Eight phobics and three patients suffering from pathological grief reactions served as subjects. A time-frequency ERP (...) analysis revealed that subjects' ERPs classified the unconscious conflict words better subliminally than supraliminally, while the reverse was true for the conscious symptom words = 2.82, p = .011). The relationship between frequency and latency revealed a similar mirror image pattern for the unconscious conflict and conscious symptom words . This method demonstrated that objective, brain-based evidence for unconscious conflict can be obtained. (shrink)

P3 is the most prominent of the electrical potentials of the human electroencephalogram that are sensitive to psychological variables. According to the most influential current hypothesis about its psychological significance [E. Donchin's], the “context updating” hypothesis, P3 reflects the updating of working memory. This hypothesis cannot account for relevant portions of the available evidence and it entails some basic contradictions. A more general formulation of this hypothesis is that P3 reflects the updating of expectancies. This version implies that P3-evoking stimuli (...) are initially unexpected but later become expected. This contradiction cannot be resolved within this formulation. The alternative “context closure” hypothesis retains the concept of “strategic information processing” emphasized by the context updating hypothesis. P3s are evoked by events that are awaited when subjects deal with repetitive, highly structured tasks; P3s arise from subjects' combining successive stimuli into larger units. The tasks in which P3s are elicited can accordingly be classified in terms of their respective formal sequences of stimuli. P3 may be a physiological indicator of excess activation being released from perceptual control areas. (shrink)

Dysfunctional attentional control is observed in patients with mental disorders. However, there is no established neurophysiological method to assess attention in such patients. We showed a discrepancy in alpha-band power in the tasks that evoked internal and external attention event-related alpha-band power changes in healthy subjects during self-reflection and working memory tasks in a preliminary study. In this study, we aimed at elucidating event-related alpha-band power changes in healthy subjects during the tasks, addressing the shortcomings of (...) the previous study. Sixteen healthy volunteers were examined for the event-related power change during the tasks. The results demonstrated the discrepancy of alpha-band ERpow at 8, 10, and 12 Hz in the parieto-occipital area between the WM and SR tasks for a period between a target stimulus and a command stimulus, where a participant switched to internal attention from external attention according to the SR task and remained at external attention according to the WM task. The results suggest that alpha-band ERpow in this area is associated with the direction of attention in response to cognitive stimuli, indicating that the findings of ERpow during the two tasks would potentially aid in the clarification of the pathophysiology of the dysfunctional change in attention in patients with psychiatric disorders. (shrink)

ERPs (event-related potentials) correlates are largely used in cognitive psychology and specifically for analysis of semantic information processing. Previous research has underlined a strong correlation between a negative-ongoing wave (N400), more frontally distributed, and semantic linguistic or extra-linguistic anomalies. With reference to the extra-linguistic domain, our experiment analyzed ERP variation in a semantic task of comprehension of emotional facial expressions. The experiment explored the effect of expectancy violation when subjects observed congruous or incongruous emotional facial patterns. Four prototypical (...) (anger, sadness, happiness and surprise) and four morphed faces were presented. Moreover, two distinct cognitive tasks (an implicit vs an explicit elaboration) were analyzed in order to evaluate the influence of spontaneous decoding in N400-like effects. An automatic, high-order cognitive process was found, elicited by a negative ERP variation similar to the linguistic N400 effect, which allows us to explain the congruous/incongruous decoding in semantic extra-linguistic comprehension. (shrink)

Event-related desynchronization, as a proxy for mirror neuron activity, has been used as a neurophysiological marker for motor execution after mirror visual feedback. Using EEG, this study investigated ERD upon the immediate effects of single-session MVF in unimanual arm movements compared with the ERD effects occurring without a mirror, in two groups: stroke patients with left hemiplegia and their healthy counterparts. During EEG recordings, each group performed one session of mirror therapy training in three task conditions: with a (...) mirror, with no mirror, and with a covered mirror. An asymmetry index was calculated from the subtraction of the event-related spectrum perturbations between the C3 and C4 electrodes located over the sensorimotor cortices contralateral and ipsilateral to the moved arm. Results of the effect of task versus group in contralateral and ipsilateral motor areas showed that there was a significant effect of task condition at the contralateral motor area in the high beta band at C3. High beta ERD showed that the suppression was greater over the contralateral hemisphere than it was over the ipsilateral hemisphere in both study groups. The magnitude of low beta ERD in patients with stroke was more suppressed in contralesional C3 under the no mirror compared to that of the covered mirror and similarly more suppressed in ipsilesional C4 ERD under the no mirror compared to that of the mirror condition. The correlation analysis revealed that the magnitude of ERSP power correlated significantly with arm severity in the low and high beta bands in patients with stroke, and a higher asymmetry index in the low beta band was associated with higher arm functioning under the no-mirror condition. There was a shift in sensorimotor ERD toward the contralateral hemisphere as induced by MVF accompanying unimanual movement in both stroke patients and healthy controls. The use of ERD in the low beta band as a neurophysiological marker to indicate the relationships between the amount of MVF-induced ERD attenuation and motor severity, and the outcome indicator for improving stroke patients’ neuroplasticity in clinical trials using MVF are warranted to be explored in the future. (shrink)

The current work investigated whether differences in phonological overlap between the past- and present-tense forms of regular and irregular verbs can account for the graded neurophysiological effects of verb regularity observed in past-tense priming designs. Event-related potentials were recorded from 16 healthy participants who performed a lexical-decision task in which past-tense primes immediately preceded present-tense targets. To minimize intra-modal phonological priming effects, cross-modal presentation between auditory primes and visual targets was employed, and results were compared to a companion (...) intra-modal auditory study (Justus, T., Larsen, J., de Mornay Davies, P., Swick, D. (2008). Interpreting dissociations between regular and irregular past-tense morphology: evidence from event-related potentials. Cognitive, Affective, Behavioral Neuroscience, 8, 178–194.). For both regular and irregular verbs, faster response times and reduced N400 components were observed for present-tense forms when primed by the corresponding past-tense forms. Although behavioral facilitation was observed with a pseudopast phonological control condition, neither this condition nor an orthographic-phonological control produced significant N400 priming effects. Instead, these two types of priming were associated with a post-lexical anterior negativity (PLAN). Results are discussed with regard to dual- and single-system theories of inflectional morphology, as well as intra- and cross-modal prelexical priming. (shrink)

Easy of learning judgments occur before active learning begins, and it is a prediction of how difficult it will be to learn new material in future learning. This study compared the amplitude of event-related potential components and brain activation regions between high and low EOL judgments by adopting ERPs with a classical EOL judgment paradigm, aiming to confirm the ease-of-processing hypothesis. The results showed that the magnitudes of EOL judgments are affected by encoding fluency cues, and the judgment (...) magnitude increases with encoding fluency; low EOL judgments are associated with higher N400 amplitude at the left superior frontal gyrus and left middle frontal gyrus. High EOL judgments showed enlarged slow-wave potentials than low EOL judgments at the left medial temporal lobe, right ventromedial prefrontal cortex, and dorsolateral prefrontal cortex. Our results support the ease-of-processing hypothesis, particularly, by affirming that EOL judgments are affected by encoding fluency in two processing stages. N400 reflects the process of acquiring encoding fluency cues, while slow-wave indicates that individuals use encoding fluency cues for metacognitive monitoring. (shrink)

Asking people to discover the identity of a recognition test probe immediately before making a recognition judgment increases the probability of an old judgment. To inform theories of this “revelation effect,” event-related potentials were recorded for revealed and intact test items across two experiments. In Experiment 1, we used a revelation effect paradigm where half of the test probes were presented as anagrams and the other items were presented intact. The pattern of ERP results from this experiment suggested (...) that revealing an item decreases initial familiarity levels and caused the revealed items to elicit similar levels of activity. In Experiment 2, half of the probes were preceded by an addition task . The pattern of ERP effects in this study were distinct from those observed in Experiment 1. More specifically, revealed item ERPs were more negative than intact ERPs at frontal electrodes and more positive at parietal electrodes early in the interval. Later in the epoch, revealed item ERPs were more negative than intact items. These data suggest that related tasks decrease familiarity and alter the signal-to-noise ratio of old and new items, whereas unrelated tasks affect processing in a different way that also results in the revelation effect. The implications for current theories of the revelation effect are discussed. (shrink)

The present study is the first to measure event-related potentials associated with the processing of the emotional Stroop task with the use of an orthogonal factorial manipulation for emotional valence, arousal, and subjective significance. The current study aimed to investigate concurrently the role of the three dimensions describing the emotion-laden words for interference control measured in the classical version of the EST paradigm. The results showed that reaction times were affected by the emotional valence of presented words and (...) the interactive effect of valence and arousal. The expected emotional arousal effect was only found in behavioral results for neutrally valenced words. Electrophysiological results showed valence and subjective significance correlated with the amplitude differences in the P2 component. Moreover, the amplitude of the N450 component varied with the level of subjective significance. This study also demonstrated that exploratory event-related potential analysis provides additional information beyond the classical component-based analysis. The obtained results show that cognitive control effects in the EST may be altered by manipulation in the subjective significance dimension. (shrink)

This study investigated the effect of obstructive sleep apnea on the neural mechanism of visual perception. A preliminary case-control study was conducted. Seventeen patients with moderate to severe OSA in the sleep center of Civil Aviation General Hospital and 20 healthy controls matched for age, sex, and education were recruited. The participants accepted the perceptual contour integration task, compared the differences in behavioral indicators between the two groups, and compared the differences in electroencephalography data between the two groups through (...) class='Hi'>event-related potential technology. The groups did not differ significantly in age and gender, but they differed significantly in body mass index. The groups were not statistically different in terms of sleep structure and total sleep time. AHI, sleep efficiency, and minimal SaO2 value in the OSA group were significantly different from those of the control group. The results showed that the average reaction time of the OSA group was significantly longer than that of the healthy control group in the contour integration task. There was no significant difference in the accuracy rate. The results of EEG showed that the amplitudes of N100 of the OSA group were significantly higher than those of the control group at O1, Oz, and O2 electrodes. There was no significant difference in latency between the two groups. At the FCz electrode, the amplitudes of N200 of the OSA group were significantly higher than those of the control group. Therefore, we concluded that in the early stage of the perceptual integration task, although the neural response activity of patients with moderate and severe OSA was not accelerated, they need to call on more psychological resources, activate more neurons in the contour global recognition processing stage, and the compensatory effect of frontal lobe appeared in the stage of visual perception. (shrink)

This study examines the event- related brain potential of 25 Mexican monolingual Spanish-speakers when reading Spanish sentences with single entity anaphora or complex anaphora. Complex anaphora is an expression that refer to propositions, states, facts or events while, a single entity anaphora is an expression that refers back to a concrete object. Here we compare the cognitive cost in processing a single entity anaphora [éstafeminine; La renuncia ] from a complex anaphora [estoneuter; La renuncia fue aceptada ]. Ésta (...) elicited a larger positive peak at 200 ms, and esto elicited a larger frontal negativity around 400 ms. The positivity resembles the P200 component, and its amplitude is thought to represent an interaction between predictive qualities in sentence processing. Unlike parietal negativities, frontal negativities are thought to represent the ease by which pronouns are linked with its antecedent, and how easy the information is recovered from short-term memory. Thus, the complex anaphora recruited more cognitive resources than the single entity anaphora. We also included an ungrammatical control sentence [éstemasculine; La renuncia ] to better understand the unique processes behind complex anaphoric resolution, as opposed to just general difficulty in sentence processing. In this case, event-related potentials elicited by éstemasculine and éstafeminine were compared. Again, ésta elicited a larger P200. However, different from the experimental condition, a left anterior negativity effect was observed for éste; the ungrammatical condition. Altogether, the present research provides electrophysiological evidence indicating that demonstrative pronouns with different morphosyntactic features and discourse parameters interact during the first stage of anaphoric processing of anaphora. This stage initiated as early as 200 milliseconds after the pronoun onset and probably ends around 400 ms. (shrink)

This study explored the syntactic transfer effect of the non-local subject-verb agreement structure with plural head noun after two intensive phases of input training with event-related potentials (ERP). The non-local subject-verb agreement stimuli with the plural head nouns, which never appeared in training phases, were used for the stimuli. A total of 26 late L1-Chinese L2-English learners, who began to learn English after a critical period and participated in our previous experiments, were asked back to take part in (...) this syntactic transfer experiment. Results indicated that a significant ERP component P600 occurred in the key region (the verb) of the sentences with syntactic violations in the experimental group, but none occurred in the control group. This demonstrated that there was a significant transfer effect of the input training. The possible theoretical explanation was provided and also the malleability of the late L2 learners was discussed. (shrink)

This splendid volume reviews a productive period of research aimed at connecting brain and mind through the use of scalp- recorded brain potentials to chart the temporal course of information processing in the human brain.... The book that Rugg, Coles, and their collaborators have produced can serve both as a summary of where we have been and as a pointer of the way ahead." M Posner Event-related potential methodology has long been used in neuroscience to measure electrical activity (...) in the brain. It has become clear, however, that it can be a powerful took in studying and illuminating central psychological issues relating to attention, information, processing, dynamics, memory, and language. Linking this technology to newer imaging techniques such as positron emission tomography and functional magnetic resonance imaging, it becomes possible to build up a spatial and temporal picture of the brain during the performance of high-level skills. This volume provides strong evidence that cognitive psychology can benefit from the use of brain electrical activity, and will be of great interest to neuroscientists and psychologists alike. (shrink)