Positive Event-related Potentials Research Articles

Motivational processing of food cues in anorexia nervosa: a pilot study

Current literature suggests an increased attentional bias toward food stimuli in eating-disordered individuals compared to healthy controls. In line with these research efforts, the present study aims to investigate the processing of food stimuli (enriched by emotional stimuli) between patients diagnosed for anorexia nervosa (AN) and healthy controls by means of electroencephalography. Twenty-two female adolescents (eleven AN patients vs. eleven healthy controls) were investigated. Positive event-related potentials "P300" and "late positive potential" (LPP) reflecting attentional processing (caused by motivationally relevant stimuli) were investigated during passive viewing of the food cue picture stream. This method was used for the first time in a sample of individuals with AN. As a main result, AN patients exhibited a higher amount of attentional bias in P300 and LPP, while watching food stimuli. Moreover, AN patients rated food stimuli as less pleasant. For a conclusion, there is substantial evidence pointing to an abnormal attentional brain reactivity to food pictures in AN. Therefore, food stimuli seem to be more motivationally relevant for AN patients than for healthy controls. By broadening existing knowledge, these findings might bear some implications for the treatment for AN. However, further research is recommended in order to confirm the results coming from rather limited data.

Differential familiarity effects in amodal completion: Support from behavioral and electrophysiological measurements.

We studied the effects of learning on amodal completion of partly occluded shapes. Amodal completion may originate from local characteristics of the partly occluded contours, resulting in local completions, or from global characteristics, resulting in global completions. Two classes of occlusion patterns were constructed: convergent occlusion patterns, in which global and local completions resulted in the same shape, and the much more ambiguous divergent occlusion patterns, in which these completions resulted in different shapes. We used a sequential matching paradigm and obtained behavioral responses (Experiment 1s and 2) and electroencephalogram recordings (Experiment 3) to investigate whether previously learned shapes influenced completions of partly occluded shapes. Experiment 1 revealed the preference for different completions of both occlusion patterns. In Experiment 2, learning effects were found only for test shapes following divergent occlusion patterns. Experiment 3 showed differential effects with regard to convergent and divergent occlusion patterns on a positive event-related potential in the 150- to 300-ms range, before learning. After learning, modulation of this effect was only found for the divergent occlusion patterns. The results show that amodal completion of shapes can be influenced by a simple learning task when multiple completions of partly occluded shapes are perceptually plausible.

A New Association Evaluation Stage in Cartoon Apprehension: Evidence from an ERP Study

The aim of this study was to investigate the temporal cortical activation patterns underlying different stages of humor comprehension (e.g., detection of incongruity stage, resolution of incongruity stage, and affective stage). Event-related potentials (ERPs) were measured when 16 subjects were apprehending cartoon pictures including humorous, non-humorous and unrelated items. Results showed that both humorous and unrelated items elicited a more negative ERP deflection (N500-800) than non-humorous ones between 500 - 800 ms, which might reflect detection to incongruent element during humor apprehension. Then, both humorous and non-humorous items elicited a more positive ERP deflection (P800-1000) than unrelated ones between 800 - 1000 ms, which might reflect a classification process preliminarily evaluating whether there were attainable cues in the pictures used to form possible association between context and picture (we named it “association evaluation” stage). Furthermore, humorous items elicited a more positive slow wave than non-humorous items which also elicited a more positive wave than unrelated items between 1000 - 1600 ms, during which this component might be involved in the forming of novel associations (resolution of incongruity). Lastly, between 1600 - 2000 ms, humorous items elicited a more positive ERP deflection (P1600-2000) than both non-humorous and unrelated items, which might be related to emotion processing during humor apprehension. Based on these results, we deeply subdivided the second stage (resolution of incongruity) into two stages: association evaluation and incongruity resolution.

Modulation of frontal and parietal neuronal activity by visuomotor learning. An ERP analysis of implicit and explicit pursuit tracking tasks

The present study investigated changes in frontal and parietal activity related to visuomotor learning. Improvement in task performance should be achieved by a transition from feedback control to feedforward control. Event-related potential (ERP) activity related to visual feedback analysis of successful error corrections was expected to decrease at parietal scalp locations. (Pre-) motor activity related to the execution of directional changes should increase and begin earlier.While using a mouse or a joystick for cursor control, subjects performed four different conditions of a pursuit tracking task in a between-subject design. To increase task difficulty, and to set up an implicit learning condition, the gain between mouse/joystick movement and cursor movement increased during the middle of each tracking trial. Subjects were informed about this manipulation in the explicit task only. Within the continuous movement of 12s duration, ERPs were assigned to phasic changes of target and cursor direction.Visuomotor learning was mainly achieved by a continuous reduction of target and cursor distance. A fronto-central positive ERP component related to the execution of a directional change increased earlier after learning. This indicates an anticipated directional change, improving task performance. ERP activity after error corrections decreased after learning, indicating either a higher efficiency or a reduced demand in visual feedback control. Activity difference was shifted from parietal to fronto-central sites later indicating a relation to improved feedforward control. No clear difference between implicit and explicit learning was observed for behavioural and ERP data.

Neural Correlates of Self-Appraisals in the Near and Distant Future: An Event-Related Potential Study

To investigate perceptual and neural correlates of future self-appraisals as a function of temporal distance, event-related potentials (ERPs) were recorded while participants (11 women, eight men) made judgments about the applicability of trait adjectives to their near future selves (i.e., one month from now) and their distant future selves (i.e., three years from now). Behavioral results indicated people used fewer positive adjectives, more negative adjectives, recalled more specific events coming to mind and felt more psychologically connected to the near future self than the distant future self. Electrophysiological results demonstrated that negative trait adjectives elicited more positive ERP deflections than did positive trait adjectives in the interval between 550 and 800 ms (late positive component) within the near future self condition. However, within the same interval, there were no significant differences between negative and positive traits adjectives in the distant future self condition. The results suggest that negative emotional processing in future self-appraisals is modulated by temporal distance, consistent with predictions of construal level theory.

Comparison Enhances Size Sensitivity: Neural Correlates of Outcome Magnitude Processing

Magnitude is a critical feature of outcomes. In the present study, two event-related potential (ERP) experiments were implemented to explore the neural substrates of outcome magnitude processing. In Experiment 1, we used an adapted gambling paradigm where physical area symbols were set to represent potential relative outcome magnitudes in order to exclude the possibility that the participants would be ignorant of the magnitudes. The context was manipulated as total monetary amount: ¥4 and ¥40. In these two contexts, the relative outcome magnitudes were ¥1 versus ¥3, and ¥10 versus ¥30, respectively. Experiment 2, which provided two area symbols with similar outcome magnitudes, was conducted to exclude the possible interpretation of physical area symbol for magnitude effect of feedback–related negativity (FRN) in Experiment 1. Our results showed that FRN responded to the relative outcome magnitude but not to the context or area symbol, with larger amplitudes for relatively small outcomes. A larger FRN effect (the difference between losses and wins) was found for relatively large outcomes than relatively small outcomes. Relatively large outcomes evoked greater positive ERP waves (P300) than relatively small outcomes. Furthermore, relatively large outcomes in a high amount context elicited a larger P300 than those in a low amount context. The current study indicated that FRN is sensitive to variations in magnitude. Moreover, relative magnitude was integrated in both the early and late stages of feedback processing, while the monetary amount context was processed only in the late stage of feedback processing.

Modality-match effect in false recognition

In the Deese-Roediger-McDermott (DRM) paradigm, participants falsely recall or recognize a nonpresented word (critical lure), highly associated with previously studied words. As numerous DRM studies have found a robust false memory effect at the behavioural level, event-related potentials (ERPs) studies have searched for possible overlapping in brain electrical activity between true and false memory. Using the DRM paradigm, the present experiment manipulated the sensory modality of stimulus presentation (auditory vs. visual) in the study phase to analyse the effect of modality match between study and test on true and false recognition. Words were therefore presented either visually or auditorily at study and always visually at test. True recognition was found to be significantly higher in the modality 'match' condition (visual-visual) than in the 'mismatch' condition (auditory-visual), whereas there was no modality-match effect on false recognition of critical lures. A general, overlapping was found between ERP correlates of true and false recognition: FN400 (300-500 ms), left-parietal (400-800 ms) and late right-frontal (1000-1500 ms) old/new effects were similar for both studied words and critical lures. No sensory modality-match effect was associated with FN400 or left-parietal old/new effects. Only the late right-frontal activity was modulated by modality manipulation, with significantly more positive ERPs in the modality-match condition. Sensory modality match of stimulus presentation, therefore, dissociated true and false recognition memory only at the behavioural level but not at the ERP level. Overall, true and false recognition memories seem to share common underlying processes.

Neural Correlates of Successful Encoding in Schizophrenia: An Event-Related Potential Study

Event Abstract Back to Event Neural Correlates of Successful Encoding in Schizophrenia: An Event-Related Potential Study Amity E. Green1*, Paul B. Fitzgerald1, Patricia T. Michie2, Pradeep J. Nathan3, 4 and Rodney J. Croft5, 6 1 Monash Alfred Psychiatry Research Centre, Monash University and the Alfred Hospital, Australia 2 University of Newcastle, School of Psychology, Australia 3 School of Psychology and Psychiatry, Monash University, Australia 4 Brain Mapping Unit, Department of Psychiatry, University of Cambridge, United Kingdom 5 Illawarra Health & Medical Research Institute, University of Wollongong, Australia 6 School of Psychology, University of Wollongong, Australia Aims: Individuals with schizophrenia demonstrate pronounced deficits in cognitive processing with particular impairments in episodic memory. This may reflect a difficulty in the ability to encode new information. The subsequent memory paradigm has been used in the study of memory formation to segregate neural processes responsible for successful encoding. In healthy controls subsequently remembered items are associated with a more positive ERP waveform than those later forgotten. The aim of the study was to investigate neural correlates of encoding in schizophrenia using a subsequent memory paradigm. Method: EEG was recorded in 20 patients and 19 healthy controls during the semantic encoding of single words. ERPs were sorted according to whether words were subsequently recognised. Group differences were determined in late positivity (LPP; area under the curve 450-750ms), as well as for N1, P2 and N400 ERP peak amplitudes, as a function of subsequent recognition. Results: Patients tended to perform poorer than controls on the recognition test (slower [p=0.069] and less accurate [p=0.006]). Mean amplitude of the encoding-related LPP was greater for recognised than not-recognised words (p=0.035, eta-squared=0.12), with patients showing reduced mean amplitude compared to controls regardless of whether the word was recognised (p=0.018, eta-squared=0.15). Further, compared to controls, patients showed significantly reduced P2 (p=0.032, eta-squared=0.11) and frontal N400 peak amplitudes (p=0.012, eta-squared=0.15) during encoding. Conclusions: The results suggest that reduced activation of encoding processes contributes to poorer recognition memory performance in schizophrenia, however the relative importance of early attentional (P2) and later sematic processing (N400 and LPP) alternations cannot be determined from the present study. Acknowledgements This research was funded by the National Health & Medical Research Council of Australia, Project Grant #502910 Keywords: Schizophrenia, episodic memory, encoding, event-related potential (ERP), susbsequent memory paradigm Conference: ASP2013 - 23rd Annual meeting of the Australasian Society for Psychophysiology, Wollongong, Australia, 20 Nov - 22 Nov, 2013. Presentation Type: Poster Presentation Topic: Memory Citation: Green AE, Fitzgerald PB, Michie PT, Nathan PJ and Croft RJ (2013). Neural Correlates of Successful Encoding in Schizophrenia: An Event-Related Potential Study. Conference Abstract: ASP2013 - 23rd Annual meeting of the Australasian Society for Psychophysiology. doi: 10.3389/conf.fnhum.2013.213.00023 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 25 Oct 2013; Published Online: 05 Nov 2013. * Correspondence: Ms. Amity E Green, Monash Alfred Psychiatry Research Centre, Monash University and the Alfred Hospital, Melbourne, Australia, amity.green@monash.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Amity E Green Paul B Fitzgerald Patricia T Michie Pradeep J Nathan Rodney J Croft Google Amity E Green Paul B Fitzgerald Patricia T Michie Pradeep J Nathan Rodney J Croft Google Scholar Amity E Green Paul B Fitzgerald Patricia T Michie Pradeep J Nathan Rodney J Croft PubMed Amity E Green Paul B Fitzgerald Patricia T Michie Pradeep J Nathan Rodney J Croft Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Vocal emotions influence verbal memory: Neural correlates and interindividual differences

Past research has identified an event-related potential (ERP) marker for vocal emotional encoding and has highlighted vocal-processing differences between male and female listeners. We further investigated this ERP vocal-encoding effect in order to determine whether it predicts voice-related changes in listeners' memory for verbal interaction content. Additionally, we explored whether sex differences in vocal processing would affect such changes. To these ends, we presented participants with a series of neutral words spoken with a neutral or a sad voice. The participants subsequently encountered these words, together with new words, in a visual word recognition test. In addition to making old/new decisions, the participants rated the emotional valence of each test word. During the encoding of spoken words, sad voices elicited a greater P200 in the ERP than did neutral voices. While the P200 effect was unrelated to a subsequent recognition advantage for test words previously heard with a neutral as compared to a sad voice, the P200 did significantly predict differences between these words in a concurrent late positive ERP component. Additionally, the P200 effect predicted voice-related changes in word valence. As compared to words studied with a neutral voice, words studied with a sad voice were rated more negatively, and this rating difference was larger, the larger the P200 encoding effect was. While some of these results were comparable in male and female participants, the latter group showed a stronger P200 encoding effect and qualitatively different ERP responses during word retrieval. Estrogen measurements suggested the possibility that these sex differences have a genetic basis.

Strategic retrieval and retrieval orientation in reality monitoring studied by event-related potentials (ERPs)

Reality monitoring requires the differentiation between perceived and imagined events or between our own actions and the actions of others. The role of control processes in reality monitoring is yet not fully understood. In the current event-related potential (ERP) study, we investigated such control processes in the form of retrieval orientation and strategic retrieval of nontarget information. At study, complete or incomplete object words were presented in sentences. Participants had to identify the words as the subject of the sentence (perceive condition) or had to complete them upon presentation of a word fragment (self-generate condition). The participants' memory accuracy was better for generated items than for perceived items, as tested in a subsequent memory exclusion task. Comparison of ERPs to new items between the two test conditions (i.e. assessing retrieval orientation) showed more positive ERPs when generated object names were targeted. Retrieval orientation also modulated the early midfrontal old/new effect: Items of the self-generate condition elicited this effect irrespective of their target/nontarget status, while in response to the less well remembered items of the perceive condition it was only found when these items were defined as targets. Target retrieval (as reflected in the left-parietal old/new effect) occurred in both test conditions, but nontarget retrieval was observed only for generated items (when perceived items were targeted). Current findings indicate that retrieval orientation can modulate familiarity-related processes. The selective occurrence of nontarget retrieval for generated items corroborates the concept that the ease with which nontarget information can be accessed promotes nontarget retrieval.

An ERP Study on Decisions between Attractive Females and Money

To investigate the neural processes of decision-makings between attractive females and money, we recorded 18 male participants' brain event-related potentials (ERPs) when they performed a novel task of deciding between viewing an attractive female's fuzzy picture in clear and gaining a certain amount of money. Two types of attractive females were included: sexy females and beautiful females. Several new electrophysiological discoveries were obtained as following. First, the beautiful females vs. money task (task B) elicited a larger positive ERP deflection (P2) than the sexy females vs. money task (task S) between 290 and 340 ms, and this probably related to the perception matching process between a visual input and an internal representation or expectation. Second, task S evoked greater negative ERP waves (N2) than task B during the time window of 340–390 ms, and this might relate to response conflict and cognitive monitoring for impulsive tendency. Third, the ERP positivity in task S was larger than task B in the time interval of 550–1000 ms, reflecting that sexy female images may have higher decision value for males than beautiful female images. Fourth, compared with choosing to gain money, choosing to view an attractive female evoked a larger late positive component (LPC) during the same time window, possibly because attractive females are more direct and evolutionarily earlier rewards for males than money amounts.

False memory and level of processing effect

Event-related potentials (ERPs) were used to determine the effects of level of processing on true and false memory, using the Deese-Roediger-McDermott (DRM) paradigm. In the DRM paradigm, lists of words highly associated to a single nonpresented word (the 'critical lure') are studied and, in a subsequent memory test, critical lures are often falsely remembered. Lists with three critical lures per list were auditorily presented here to participants who studied them with either a shallow (saying whether the word contained the letter 'o') or a deep (creating a mental image of the word) processing task. Visual presentation modality was used on a final recognition test. True recognition of studied words was significantly higher after deep encoding, whereas false recognition of nonpresented critical lures was similar in both experimental groups. At the ERP level, true and false recognition showed similar patterns: no FN400 effect was found, whereas comparable left parietal and late right frontal old/new effects were found for true and false recognition in both experimental conditions. Items studied under shallow encoding conditions elicited more positive ERP than items studied under deep encoding conditions at a 1000-1500 ms interval. These ERP results suggest that true and false recognition share some common underlying processes. Differential effects of level of processing on true and false memory were found only at the behavioral level but not at the ERP level.

Neural Mechanisms Underlying the Cost of Task Switching: An ERP Study

BackgroundWhen switching from one task to a new one, reaction times are prolonged. This phenomenon is called switch cost (SC). Researchers have recently used several kinds of task-switching paradigms to uncover neural mechanisms underlying the SC. Task-set reconfiguration and passive dissipation of a previously relevant task-set have been reported to contribute to the cost of task switching.Methodology/Principal FindingsAn unpredictable cued task-switching paradigm was used, during which subjects were instructed to switch between a color and an orientation discrimination task. Electroencephalography (EEG) and behavioral measures were recorded in 14 subjects. Response-stimulus interval (RSI) and cue-stimulus interval (CSI) were manipulated with short and long intervals, respectively. Switch trials delayed reaction times (RTs) and increased error rates compared with repeat trials. The SC of RTs was smaller in the long CSI condition. For cue-locked waveforms, switch trials generated a larger parietal positive event-related potential (ERP), and a larger slow parietal positivity compared with repeat trials in the short and long CSI condition. Neural SC of cue-related ERP positivity was smaller in the long RSI condition. For stimulus-locked waveforms, a larger switch-related central negative ERP component was observed, and the neural SC of the ERP negativity was smaller in the long CSI. Results of standardized low resolution electromagnetic tomography (sLORETA) for both ERP positivity and negativity showed that switch trials evoked larger activation than repeat trials in dorsolateral prefrontal cortex (DLPFC) and posterior parietal cortex (PPC).Conclusions/SignificanceThe results provide evidence that both RSI and CSI modulate the neural activities in the process of task-switching, but that these have a differential role during task-set reconfiguration and passive dissipation of a previously relevant task-set.

Cognitive control in belief‐laden reasoning during conclusion processing: An ERP study

Belief bias is the tendency to accept conclusions that are compatible with existing beliefs more frequently than those that contradict beliefs. It is one of the most replicated behavioral findings in the reasoning literature. Recently, neuroimaging studies using functional magnetic resonance imaging (fMRI) and event-related potentials (ERPs) have provided a new perspective and have demonstrated neural correlates of belief bias that have been viewed as supportive of dual-process theories of belief bias. However, fMRI studies have tended to focus on conclusion processing, while ERPs studies have been concerned with the processing of premises. In the present research, the electrophysiological correlates of cognitive control were studied among 12 subjects using high-density ERPs. The analysis was focused on the conclusion presentation phase and was limited to normatively sanctioned responses to valid-believable and valid-unbelievable problems. Results showed that when participants gave normatively sanctioned responses to problems where belief and logic conflicted, a more positive ERP deflection was elicited than for normatively sanctioned responses to nonconflict problems. This was observed from -400 to -200 ms prior to the correct response being given. The positive component is argued to be analogous to the late positive component (LPC) involved in cognitive control processes. This is consistent with the inhibition of empirically anomalous information when conclusions are unbelievable. These data are important in elucidating the neural correlates of belief bias by providing evidence for electrophysiological correlates of conflict resolution during conclusion processing. Moreover, they are supportive of dual-process theories of belief bias that propose conflict detection and resolution processes as central to the explanation of belief bias.

Patients with persistent pain after breast cancer surgery show both delayed and enhanced cortical stimulus processing

BackgroundWomen who undergo breast cancer surgery have a high risk of developing persistent pain. We investigated brain processing of painful stimuli using electroencephalograms (EEG) to identify event-related potentials (ERPs) in patients with persistent pain after breast cancer treatment.MethodsNineteen patients (eight women with persistent pain, eleven without persistent pain), who were surgically treated more than 1 year previously for breast cancer (mastectomy, lumpectomy, and axillary lymph node dissection) and/or had chemoradiotherapy, were recruited and compared with eleven healthy female volunteers. A block of 20 painful electrical stimuli was applied to the calf, somatopically remote from the initially injured or painful area. Simultaneously an EEG was recorded, and a visual analog scale (VAS) pain rating obtained.ResultsIn comparison with healthy volunteers, breast cancer treatment without persistent pain is associated with accelerated stimulus processing (reduced P260 latency) and shows a tendency to be less intense (lower P260 amplitude). In comparison to patients without persistent pain, persistent pain after breast cancer treatment is associated with stimulus processing that is both delayed (ie, increased latency of the ERP positivity between 250–310 ms [P260]), and enhanced (ie, enhanced P260 amplitude).ConclusionThese results show that treatment and persistent pain have opposite effects on cortical responsiveness.

When bilinguals choose a single word to speak: Electrophysiological evidence for inhibition of the native language

Behavioral and event-related potential (ERP) measures are reported for a study in which relatively proficient Chinese–English bilinguals named identical pictures in each of their two languages. Production occurred only in Chinese (the first language, L1) or only in English (the second language, L2) in a given block with the order counterbalanced across participants. The repetition of pictures across blocks was expected to produce facilitation in the form of faster responses and more positive ERPs. However, we hypothesized that if both languages are activated when naming one language alone, there might be evidence of inhibition of the stronger L1 to enable naming in the weaker L2. Behavioral data revealed the dominance of Chinese relative to English, with overall faster and more accurate naming performance in L1 than L2. However, reaction times for naming in L1 after naming in L2 showed no repetition advantage and the ERP data showed greater negativity when pictures were named in L1 following L2. This greater negativity for repeated items suggests the presence of inhibition rather than facilitation alone. Critically, the asymmetric negativity associated with the L1 when it followed the L2 endured beyond the immediate switch of language, implying long-lasting inhibition of the L1. In contrast, when L2 naming followed L1, both behavioral and ERP evidence produced a facilitatory pattern, consistent with repetition priming. Taken together, the results support a model of bilingual lexical production in which candidates in both languages compete for selection, with inhibition of the more dominant L1 when planning speech in the less dominant L2. We discuss the implications for modeling the scope and time course of inhibitory processes.

Updating of Visual Space Across Horizontal Saccades in Cerebellar and Thalamic Lesion Patients

Efference copies of motor commands are used to update visual space across saccades, ultimately ensuring transsaccadic constancy of space. Thalamic lesions have been shown to impair efference copy-based saccadic updating in an oculomotor context, i.e., when two successive saccades are required. Moreover, the cerebellum has also been discussed as one possible source of saccade-related efference copy signals. The present study aimed to investigate the effects of thalamic and cerebellar lesions on saccadic updating in a perceptual context. To this end, seven patients with focal cerebellar lesions, seven patients with focal thalamic lesions and 11 healthy controls completed a perceptual localisation task in which the position of a target had to be updated across a single horizontal saccade, while saccade-related event-related potentials (ERPs) were recorded. Contrary to the expectations, localisation precision in both patient groups did not differ from the respective controls. A positive ERP component with centroparietal distribution occurring from about 300 to 500 ms after saccade onset in the updating condition was observed equally pronounced in controls and thalamic lesion patients. In cerebellar lesion patients, there was evidence of a reduction of this relative positivity in the updating condition, particularly for leftward saccades. This finding suggests that cerebellar damage altered the neural processes underlying saccadic updating in a perceptual context without causing overt behavioural deficits.

Demonstrating emotional processing differences in psychopathy using affective ERP modulation

Psychopaths exhibit abnormalities processing emotional information, but there is less certainty regarding the role attention plays in these processes. We present data from two affective picture-viewing tasks comparing event-related potential (ERP) modulation effects when emotional information is present but not task relevant (Task 1) followed by a condition directing attention to the categorization of emotional content (Task 2). Controls show a robust, persistent ERP positivity (200-900 ms) associated with emotional target photos compared to neutral targets in both tasks. Individuals with psychopathy only showed this differentiation when explicitly attending to the emotional content of the photos (Task 2), and these effects remained smaller than the amplitude differences demonstrated by controls. Although abnormal allocation of attention may play a critical role, this cannot completely account for emotional processing deficits associated with psychopathy.

Differentiation of stages in joke comprehension: Evidence from an ERP study

This study aimed to investigate the mechanisms underlying joke comprehension using event-related potentials (ERPs). Fourteen healthy college students were presented with the context of a story without its joke or nonjoke ending, and then, when the story ending was presented, they were asked to make a funny/unfunny judgment about these endings. The behavioral results showed that there was no significant difference between funny and unfunny items, which meant that subjects could understand funny items as easily as unfunny ones. However, the ERP results showed that funny items initially elicited a more negative ERP deflection (N350-450) over frontocentral scalp regions. Dipole analysis localized the generators in the left temporal gyrus and the left medial frontal gyrus; it is suggested that these areas might be involved in detecting the incongruent element in joke comprehension. Between 600 and 800 ms, funny items subsequently elicited a more negative ERP deflection (N600-800) over frontocentral scalp regions and a more positive ERP deflection (P600-800) over posterior scalp regions. Dipole analysis localized the generator in the anterior cingulate cortex (ACC), an area involved in the breaking of mental set/expectation and the forming of novel associations. Finally, funny items elicited a more positive ERP deflection (P1250-1400) over anterior and posterior scalp regions. Dipole analysis localized the generators in the middle frontal gyrus and the fusiform gyrus, areas that might be related to the affective appreciation stage in joke process. Unlike that of Coulson and Kutas (2001), the present study might support the hypothesis of a three stage model of humor processing (humor detection, resolution of incongruity and humor appreciation).

Similar neural correlates for language and sequential learning: Evidence from event-related brain potentials

We used event-related potentials (ERPs) to investigate the time course and distribution of brain activity while adults performed (1) a sequential learning task involving complex structured sequences and (2) a language processing task. The same positive ERP deflection, the P600 effect, typically linked to difficult or ungrammatical syntactic processing, was found for structural incongruencies in both sequential learning as well as natural language and with similar topographical distributions. Additionally, a left anterior negativity (LAN) was observed for language but not for sequential learning. These results are interpreted as an indication that the P600 provides an index of violations and the cost of integration of expectations for upcoming material when processing complex sequential structure. We conclude that the same neural mechanisms may be recruited for both syntactic processing of linguistic stimuli and sequential learning of structured sequence patterns more generally.