An ERP study of syntactic processing in English and nonsense sentences

The timecourse of the interaction between syntactic and semantic information during sentence processing in monolingual native English speakers was investigated using event-related potentials (ERPs). To examine the effects of semantic information on syntactic processing, the results for normal English sentences were compared to those for semantically impoverished nonsense (Jabberwocky) sentences. Within each sentence type condition, half of the sentences contained a syntactic violation. Violations elicited a larger amplitude N1 and more negative ERPs around 200 ms after the onset of the critical word relative to the grammatical condition. Although these effects were observed in both sentence types, they were anteriorly distributed for English sentences only. Moreover, the P600 elicited by the syntactic violation was attenuated in processing Jabberwocky as compared to English sentences. These results suggest that semantic and syntactic information are integrated during the earlier stages of syntactic processing indexed by the anterior negativities, and that these interactions continue in the later stages of processing indexed by the P600.     

Cognitive processes in two-point discrimination: an ERP study.

OBJECTIVE: To elucidate the temporal features of the cognitive process in two-point discrimination (TPD). METHODS: We measured somatosensory event-related potentials (ERPs) in 9 subjects during the TPD task, in which we provided a pair of electrical pulses simultaneously, altering the distance between the electrodes. We analyzed the TPD-related ERPs and investigated the relationship between the potentials and the subjects' judgments. RESULTS: During the TPD task, a negative potential approximately 140 ms after the stimulation (N140) was enhanced as compared to a stimulus counting task. Two late positive components, LPC-1 and LPC-2, whose peak latencies were 300 and 500 ms, respectively, were identified only in the TPD task. The LPC-1 was recorded dominantly in the fronto-central area, while the LPC-2 was detected dominantly in the centro-parietal area. The amplitude of the LPC-2 was significantly modulated by the degree of consistency in the subjects' judgment. On the other hand, these ERP components did not show significant difference between the alternate judgments, i.e. 'one-point' or 'two-point' judgment. CONCLUSIONS: Our results suggest that the N140 is related to the attention toward the stimulation. The LPC-1 and LPC-2 are likely to correspond to the processes represented by P3a and P3b, based on their temporal and spatial behavior.     

Processing tonal modulations: an ERP study

A common stylistic element of Western tonal music is the change of key within a musical sequence (known as modulation in musical terms). The aim of the present study was to investigate neural correlates of the cognitive processing of modulations with event-related brain potentials. Participants listened to sequences of chords that were infrequently modulating. Modulating chords elicited distinct effects in the event-related brain potentials: an early right anterior negativity reflecting the processing of a violation of musical regularities and a late frontal negativity taken to reflect processes of harmonic integration. Additionally, modulations elicited a tonic negative potential suggested to reflect cognitive processes characteristic for the processing of tonal modulations, namely, the restructuring of the "hierarchy of harmonic stability" (which specifies musical expectations), presumably entailing working memory operations. Participants were "nonmusicians"; results thus support the hypothesis that nonmusicians have a sophisticated (implicit) knowledge about musical regularities.     

The fate of sounds in conductors' brains: an ERP study

Professional music conductors are required to home in on a particular musician but at the same time have to monitor the entire orchestra. It was hypothesized that this unique experience should be reflected by superior auditory spatial processing. Event-related brain potentials were obtained, while conductors, professional pianists, and non-musicians listened to sequences of bandpass-filtered noise-bursts presented in random order from six speakers, three located in front and three to the right of the subjects. In different runs, subjects either attended the centermost or the most peripheral speaker in order to detect slightly deviant noise-bursts. For centrally located speakers, the ERPs showed a typical Nd attention effect for the relevant location with a steep decline for the neighboring speakers in all subject groups. For peripheral speakers, only the conductors showed attentional selectivity, while the Nd effect was of similar size for all three peripheral speakers in the other two groups. These ERP effects were paralleled by an enhanced behavioral selectivity in peripheral auditory space in conductors. Moreover, the pre-attentive monitoring of the entire auditory scene indexed by the mismatch negativity was superior in musicians compared to non-musicians. In conductors, the MMN was followed by a positivity suggesting an attention shift towards the deviant stimuli in this group only.     

Feedback in hypothesis testing: an ERP study

We used event-related potentials (ERPs) to probe the effects of feedback in a hypothesis testing (HT) paradigm. Thirteen college students serially tested hypotheses concerning a hidden rule by judging its presence or absence in triplets of digits and revised them on the basis of an exogenous performance feedback. ERPs time-locked to performance feedback were then examined. The results showed differences between responses to positive and negative feedback at all cortical sites. Negative feedback, indicating incorrect performance, was associated to a negative deflection preceding a P300-like wave. Spatiotemporal principal component analysis (PCA) showed the interplay between early frontal components and later central and posterior ones. Lateralization of activity was selectively detectable at frontal sites, with a left frontal dominance for both positive and negative feedback. These results are discussed in terms of a proposed computational model of trial-to-trial feedback in HT in which the cognitive and emotive aspects of feedback are explicitly linked to putative mediating brain mechanisms. The properties of different feedback types and feedback-related deficits in depression are also discussed.     

Differentiating ERAN and MMN: an ERP study

In the present study, the early right-anterior negativity (ERAN) elicited by harmonically inappropriate chords during listening to music was compared to the frequency mismatch negativity (MMN) and the abstract-feature MMN. Results revealed that the amplitude of the ERAN, in contrast to the MMN, is specifically dependent on the degree of harmonic appropriateness. Thus, the ERAN is correlated with the cognitive processing of complex rule-based information, i.e. with the application of music-syntactic rules. Moreover, results showed that the ERAN, compared to the abstract-feature MMN, had both a longer latency, and a larger amplitude. The combined findings indicate that ERAN and MMN reflect different mechanisms of pre-attentive irregularity detection, and that, although both components have several features in common, the ERAN does not easily fit into the classical MMN framework. The present ERPs thus provide evidence for a differentiation of cognitive processes underlying the fast and pre-attentive processing of auditory information.     

Differential processing of part-to-whole and part-to-part face priming: an ERP study.

We provide electrophysiological evidence supporting the hypothesis that part and whole face processing involve distinct functional mechanisms. We used a congruency judgment task and studied part-to-whole and part-to-part priming effects. Neither part-to-whole nor part-to-part conditions elicited early congruency effects on face-specific ERP components, suggesting that activation of the internal representations should occur later on. However, these components showed differential responsiveness to whole faces and isolated eyes. In addition, although late ERP components were affected when the eye targets were not associated with the prime in both conditions, their temporal and topographical features depended on the latter. These differential effects suggest the existence of distributed neural networks in the inferior temporal cortex where part and whole facial representations may be stored.     

Recognition of objects in non-canonical views: a functional MRI study.

BACKGROUND: The neural correlate of object recognition in non-canonical views is uncertain, but there is evidence for involvement of neural pathways, possibly separate from those used for object recognition in canonical views. METHODS: Boxcar functional MRI (fMRI) techniques were used to detect neural activity while eight normal subjects were instructed to identify digital photographs of objects in non-canonical and canonical orientations. RESULTS: The right angular gyrus, the left inferior temporal gyrus, and the right cerebellum showed significant fMRI activity during non-canonical as opposed to canonical viewing. CONCLUSIONS: Subjects recognizing objects in non-canonical orientations engage in a process separate from, or in addition to, the process used in recognizing objects in canonical orientations.     

The effects of vestibular stimuli on brain cognitive processing: an ERP study

Cognition impairment caused by space motion sickness often is a risk of spaceflight. So the dynamic changes of pattern of brain cognitive processing under varied vestibular stimuli was explored using event-related potentials. Vestibular stimulation was produced by rotary chair and varied linearly, i.e. control, constant 10 degrees/s rotation and constant 0.6 degrees/s, 0.8 degrees/s, 1.0 degrees/s, 1.2 degrees/s acceleration. Thirty-three subjects participated in the study and performed same auditory selective attention task in which the odd numbers in a randomly mixed series of odd and even numbers (go/no-go) presented acoustically in Chinese pronunciation were assigned as target signal during the rotation stimuli. The results showed that the P3 latency induced by target signal and the N1P2, P2N2 and N2P3 peak-to-peak amplitudes decreased significantly during constant 10 degrees/s rotation in contrast to control and constant angular acceleration. The P3 latency induced by target signal was shorter during constant 0.6 degrees/s and 1.2 degrees/s acceleration rotations than that during constant 0.8 degrees/s and 1.0 degrees/s acceleration rotations. It was suggested that constant angular velocity rotation had a promotion effect on brain cognitive processing. The constant angular acceleration inhibited the cognitive processing and its action had at least two different levels.     

Spatial congruence in working memory: an ERP study

The Simon effect refers to the finding that reaction times are faster when stimulus and response locations are congruent than when they are not, even stimulus locations are task irrelevant. Zhang and Johnson reported a Simon-like spatial congruence effect in working memory. This study examined the neural mechanisms of this memory-based spatial congruence effect by recording event-related potentials to probe stimuli. Behavioral results showed a clear congruence effect. The P300 amplitudes were larger in the congruent condition than in the incongruent condition. The results suggest that the memory-based congruence effect and the classical Simon effect were mediated by similar neural mechanisms and support theories assigning response selection an essential role in spatial congruence effects.     

Music training and working memory: an ERP study

While previous research has suggested that music training is associated with improvements in various cognitive and linguistic skills, the mechanisms mediating or underlying these associations are mostly unknown. Here, we addressed the hypothesis that previous music training is related to improved working memory. Using event-related potentials (ERPs) and a standardized test of working memory, we investigated both neural and behavioral aspects of working memory in college-aged, non-professional musicians and non-musicians. Behaviorally, musicians outperformed non-musicians on standardized subtests of visual, phonological, and executive memory. ERPs were recorded in standard auditory and visual oddball paradigms (participants responded to infrequent deviant stimuli embedded in lists of standard stimuli). Electrophysiologically, musicians demonstrated faster updating of working memory (shorter latency P300s) in both the auditory and visual domains and musicians allocated more neural resources to auditory stimuli (larger amplitude P300), showing increased sensitivity to the auditory standard/deviant difference and less effortful updating of auditory working memory. These findings demonstrate that long-term music training is related to improvements in working memory, in both the auditory and visual domains and in terms of both behavioral and ERP measures.     

Emotional picture processing in children: an ERP study

The late positive potential (LPP) reflects increased attention to emotional versus neutral stimuli in adults. To date, very few studies have examined the LPP in children, and whether it can be used to measure patterns of emotional processing that are related to dispositional mood characteristics, such as temperamental fear and anxiety. To examine this question,39 typically developing 5–7 year olds (M age in months = 75.27, SD = 5.83) passively viewed complex emotional and neutral pictures taken from the International Affective Picture System.Maternal report of temperamental fear and anxiety was obtained and fearful behavior during an emotional challenge was observed. As documented in adults, LPP amplitudes to pleasant and unpleasant stimuli were larger than to neutral stimuli, although some gender differences emerged. Larger LPP amplitude differences between unpleasant and neutral stimuli were associated with greater observed fear. The LPP as a measure of individual differences in emotional processing is discussed.     

Effects of mental fatigue on attention: an ERP study

The effects of mental fatigue on attention were assessed. Subjects performed a visual attention task for 3 h without rest. Subjective levels of fatigue, performance measures and EEG were recorded. Subjective fatigue ratings, as well as theta and lower-alpha EEG band power increased, suggesting that the 3 h of task performance resulted in an increase in fatigue. Reaction times, misses and false alarms increased with time on task, indicating decreased performance efficiency in fatigued subjects. Subjects were unable to inhibit automatic shifting of attention to irrelevant stimuli, reflected by a larger negativity in the N1 latency range for irrelevant, compared to relevant stimuli. This difference in negativity was unaffected by time on task. However, N1 and N2b amplitude did change with time on task: N1 amplitude decreased, and the difference in N2b amplitude between relevant and irrelevant stimuli (larger N2b amplitude evoked by relevant stimuli) decreased with time on task. The results indicate a dissociation in the effects of mental fatigue on goal-directed (top-down) and stimulus-driven (bottom-up) attention: mental fatigue results in a reduction in goal-directed attention, leaving subjects performing in a more stimulus-driven fashion.     

Active processing of biological motion perception: an ERP study

The purpose of this study was to measure event-related potentials (ERPs) to clarify how attention affects neural activity during the visual perception of biological motion (BM). Thirteen healthy subjects observed BM or scrambled motion (SM). For SM, each point had the same velocity vector as in BM, but the initial starting positions were randomized. Each BM and SM was overlaid with ten noise dots and four rectangles. For the rectangles, one was or was not rotated 90 degrees relative to the others. Subjects were required to undertake two kinds of visual tasks. For the attention-to-motion condition, subjects directed their attention to the type of motion. For the attention-to-rectangle condition, subjects directed their attention to the rotational angle of the overlaid rectangles. As in our earlier study, the ERP response to the perception of BM had two negative components at approximately 200 ms (N200) and approximately 330 ms (N330) in both attentional conditions. Our analysis focused on the amplitude of the second negative component, which was sensitive to BM. There was a significant interaction between attention and the type of motion regarding the amplitude of N330. Specifically, the amplitude of N330 in response to BM was greater in the attention-to-motion condition than in the attention-to-rectangle condition, and was greater than the amplitude of the response to SM in the attention-to-motion condition. These results suggest that in this experimental design, processing of BM is modulated by attention.     

Distinctive neural signatures for negative sentences in Hindi: an fMRI study

We examined cortical activations using functional magnetic resonance imaging (fMRI) technique in skilled native Hindi readers while they performed a ‘target-probe’ semantic judgment task on affirmative and negative sentences. Hindi, an Indo-Aryan language widely spoken in India, follows subject-object-verb (SOV) order canonically but allows free word order. The common cortical regions involved in affirmative and negative sentence conditions included bilateral inferior frontal gyrus (IFG), left parietal cortex (BA 7/40), left fusiform (BA 37), bilateral supplementary motor area (SMA) (BA 6), bilateral middle temporal gyrus (BA 21), and bilateral occipital area (BA 17/18). While no distinct region was activated for affirmative sentences, we observed activations in the region of bilateral anterior temporal pole for negative sentence. The behavioral results showed no significant mean difference for reaction times (RT) and accuracy measures between affirmative and negative sentences. However, the imaging results suggest the recruitment of anterior temporal pole in processing of negative sentences. Region of interest (ROI) analysis for selected regions showed higher signal intensity for negative sentences possibly indicating the associated inherent difficulty level of processing, especially when integrating information related to negations.     

Effects of aging on visuospatial attention: an ERP study

The effects of aging on visuospatial attention were investigated with event-related brain potentials (ERPs). A central arrow pointed towards (75% valid cues) or away from (25% invalid cues) the location of upcoming visual targets to which subjects made two choice discriminations. Young and older adults responded faster following valid than invalid cues. The absolute magnitude of the cueing effect was larger for older than young subjects, but cueing effects were similar between groups when estimated proportionally to overall response time. Under the present conditions, the electrophysiological manifestations of visuospatial attention were similar for young and older adults. Early ERP components following the target stimulus (P1, N1, Nd1) were slower for older than young subjects, but amplitude was similarly affected by cueing in each group. The temporal correspondence between component latencies and the observed cueing effects are consistent with theories positing that attention amplifies the sensory gain of early perceptual processes. The observation that aging slowed latency of the ipsilateral but not the contralateral P1, is consistent with age differences in interhemispheric transfer times. A broadly distributed 200-400 ms validity effect on ERP amplitude was similar between groups in timing, spatial distribution, and magnitude. The 200-400 ms attention effect appeared to be a modulation of the P3 in younger subjects, as earlier observed. However, the present study dissociated the 200-400 ms attention effects from the P3 component because the P3 did not peak until 526 ms in older subjects.     

Lack of asymmetrical transfer for linguistic stimuli in schizophrenia: an ERP study.

OBJECTIVE: To assess the mechanisms underlying lack of speeded information transfer asymmetry (faster right to left) for verbal information in schizophrenia. METHODS: Interhemispheric transfer times (IHTT) between the hemispheres were assessed using a lateralized lexical-decision task in males with schizophrenia (N = 12) and matched controls (N = 12). Words were presented to the left visual field (LVF), right visual field (RVF), or bilaterally (BVF) while 128-channel EEG was recorded continuously. A direct measure of IHTT in each direction was obtained by comparing the latencies of the N160 evoked potential (EP) component in the hemispheres contralateral and ipsilateral to stimulation. RESULTS: Controls showed faster information transfer from the right to left hemisphere (R-to-L) for linguistic stimuli. The two groups did not differ for IHTTs L-to-R. Lack of IHTT asymmetry in the schizophrenia groups was associated with an overall concomitant decrease in the amplitude of the N160 in the right hemisphere. CONCLUSIONS: Differences in IHTT asymmetry may be attributed to lack of right hemisphere activation and not callosal dysfunction as has been previously suggested. SIGNIFICANCE: It is suggested that a relative excess of myelinated axons in the right hemisphere speeds IHTT faster R-to-L, findings are discussed with reference to differences in right hemisphere white matter connectivity in schizophrenia.     

Cognitive effects of precentral cortical stimulation for pain control: an ERP study.

Electrical stimulation of the motor cortex (MCS) is a promising and increasingly used neurosurgical technique for the control of refractory neuropathic pain. Although its mechanisms of action remain unknown, recent functional imaging data suggest involvement of the thalamus, brainstem and anterior cingulate/orbitofrontal cortex. Since some of these areas are also implicated in higher cognitive functions, notably attentional processes, we analysed cognitive ERPs and behavioural performance during an "oddball" auditory detection task in patients submitted to this procedure. Eleven consecutive patients undergoing MCS because of neuropathic refractory pain, ranging in age from 25 to 71 years, were included in the study. ERPs were obtained in all cases both during the application ("MCS-on") and within the 10 min that followed discontinuation of the procedure ("MCS-off"). In five patients, ERPs could also be obtained just before the start of MCS. When the patients' sample was taken as a whole, there were no consistent effects of MCS on the ERPs. There was, however, a significant interaction of MCS action with the patients' age, reflecting a significant delay during MCS of the cognitive responses N2 and P3 (N200 and P300) in the group of patients older than 50 years exclusively. This effect was rapidly reversible after MCS discontinuation. No MCS-related changes were observed in the N1 component. At the individual level, the effect of MCS on the endogenous ERPs was highly variable, ranging from a total stability of ERPs (mostly in younger subjects) to latency differences of tens of milliseconds in the older group. These results, together with recent experiments showing P300 alteration during repetitive transcranial stimulation, suggest that motor cortex stimulation may interfere with relatively simple cognitive processes such as those underlying target detection, and that the risk of abnormal cognitive effects related to cortical stimulation may increase with age. Although the procedure appears on the whole remarkably safe, complementary neuropsychological studies in this category of patients are advised, as well as caution to possible adverse cognitive effects when using MCS in the elderly, notably in the presence of pre-existent cerebral lesions.     

The acceleration of spoken-word processing in children's native-language acquisition: an ERP cohort study

Healthy adults can identify spoken words at a remarkable speed, by incrementally analyzing word-onset information. It is currently unknown how this adult-level speed of spoken-word processing emerges during children's native-language acquisition. In a picture-word mismatch paradigm, we manipulated the semantic congruency between picture contexts and spoken words, and recorded event-related potential (ERP) responses to the words. Previous similar studies focused on the N400 response, but we focused instead on the onsets of semantic congruency effects (N200 or Phonological Mismatch Negativity), which contain critical information for incremental spoken-word processing. We analyzed ERPs obtained longitudinally from two age cohorts of 40 primary-school children (total n = 80) in a 3-year period. Children first tested at 7 years of age showed earlier onsets of congruency effects (by approximately 70 ms) when tested 2 years later (i.e., at age 9). Children first tested at 9 years of age did not show such shortening of onset latencies 2 years later (i.e., at age 11). Overall, children's onset latencies at age 9 appeared similar to those of adults. These data challenge the previous hypothesis that word processing is well established at age 7. Instead they support the view that the acceleration of spoken-word processing continues beyond age 7.     

The development of visual- and auditory processing in Rett syndrome: an ERP study

Rett syndrome is a neurodevelopmental disorder that occurs almost exclusively in females. It is characterized by a progressive loss of intellectual functioning and motor skills, and the development of stereotypic hand movements, that occur after a period of normal development. Event-related potentials were recorded to a passive auditory- and visual oddball task in 17 females with Rett syndrome aged between 2 and 60 years, and age-matched controls. Overall the participants with Rett syndrome had longer ERP latencies and smaller ERP amplitudes than the Control group suggesting slowed information processing and reduced brain activation. The Rett groups also failed to show typical developmental changes in event-related brain activity and revealed a marked decline in ERP task modulation with increasing age.