N1 Response Research Articles

Benefits of choir singing on complex auditory encoding in the aging brain: An ERP study.

Aging is accompanied by difficulties in auditory information processing, especially in more complex sound environments. Choir singing requires efficient processing of multiple sound features and could, therefore, mitigate the detrimental effects of aging on complex auditory encoding. We recorded auditory event-related potentials during passive listening of sounds in healthy older adult (≥ 60 years) choir singers and nonsinger controls. We conducted a complex oddball condition involving encoding of abstract regularities in combinations of pitch and location features, as well as in two simple oddball conditions, in which only either the pitch or spatial location of the sounds was varied. We analyzed change-related mismatch negativity (MMN) and obligatory P1 and N1 responses in each condition. In the complex condition, the choir singers showed a larger MMN than the controls, which also correlated with better performance in a verbal fluency test. In the simple pitch and location conditions, the choir singers had smaller N1 responses compared to the control subjects, whereas the MMN responses did not differ between groups. These results suggest that regular choir singing is associated both with more enhanced encoding of complex auditory regularities and more effective adaptation to simple sound features.

Effect of cochlear implant side on early speech processing in adults with single-sided deafness

ObjectiveIn binaurally deaf subjects, speech processing particularly benefits from a cochlear implant (CI) in the right ear, which is contralateral to the commonly left speech-dominant hemisphere. However, it is unclear whether such effects of implantation side also occur in speech processing in patients with single-sided deafness (SSD). MethodsLateralization of N1 responses was analyzed with a high-density electroencephalogram (EEG) in fourteen adults with postlingually acquired left or right SSD who received a CI in adulthood. During recording, patients performed a speech and a pure-tone discrimination task. Lateralization of N1 responses was assessed by side-specific global field power (GFP) and compared (a) between normal hearing and CI-implanted ears within subjects and (b) between implantation sides across subjects. ResultsN1 responses were stronger in the contralateral than in the ipsilateral hemisphere during stimulation of the normal hearing ear (except for left speech stimulation), and was bilateral symmetric with CI stimulation on either side. A significant correlation between speech discrimination performance and left lateralization was found across subjects for the left CI ear. ConclusionsCI stimulation altered auditory processing across hemispheres. Speech discrimination in left CI-implanted SSD patients improved with left lateralization of the N1 response. SignificanceSide-specific rehabilitation in SSD patients might improve speech processing across hemispheres.

Can you change your mind? An ERP study of cognitive flexibility and new evidence integration

Cognitive flexibility is an ability that allows individuals to integrate external evidence into previous expectancies. Individual differences in this ability were examined using Event-Related Potentials (ERPs), focusing on the fact that new evidence can either confirm or disprove an initial impression. Written scenarios prompted to make a prediction while either confirmatory or disconfirmatory evidence followed. A final sentence presented participants with a statement congruent with the prediction likely to have been formed based on the first statement or a statement rather congruent with corrective new evidence. A Bias Against Disconfirmatory Evidence (BADE) test rated participants in cognitive flexibility. ERPs revealed that whereas individuals overall typically reacted to unexpected endings (a classical N400 effect) within the confirmatory evidence condition, higher cognitive flexibility scores were associated with smaller N400 effects. Furthermore, individuals showed larger P600s for disconfirmatory than confirmatory evidence conditions, regardless of the final target ending. This result indexes reanalysis processes whenever disconfirmatory evidence was present. Regression analysis of BADE scores and ERP effects are presented and discussed. Late ERP components are sensitive enough to detect new evidence integration capabilities and thus provide a good implicit measure of cognitive flexibility.

Capacity limits in sentence comprehension: Evidence from dual-task judgements and event-related potentials

There is an ongoing controversy over whether readers can access the meaning of multiple words, simultaneously. To date, different experimental methods have generated seemingly contradictory evidence in support of serial or parallel processing accounts. For example, dual-task studies suggest that readers can process a maximum of one word at a time (White, Palmer & Boynton, 2018), while ERP studies have demonstrated neural priming effects that are more consistent with parallel activation (Wen, Snell & Grainger, 2019). To help reconcile these views, I measured neural responses and behavioral accuracy in a dual-task sentence comprehension paradigm. Participants saw masked sentences and two-word phrases and had to judge whether or not they were grammatical. Grammatically correct sentences (This girl is neat) produced smaller N400 responses compared to scrambled sentences (Those girl is fled): an N400 sentence superiority effect. Critically, participants' grammaticality judgements on the same trials showed striking capacity limitations, with dual-task deficits closely matching the predictions of a serial, all-or-none processing account. Together, these findings suggest that the N400 sentence superiority effect is fully compatible with serial word recognition, and that readers are unable to process multiple sentence positions simultaneously.

Renting vs. Owning: Public Stereotypes of Housing Consumption Decision From the Perspective of Confucian Culture: Evidence From Event-Related Potentials.

The ideas of face consciousness, group conformity, extended family concept, and crisis consciousness in Confucian culture have a subtle and far-reaching impact on housing consumption decision among the Chinese public, forming a housing consumption model of “preferring to own a house rather than rent one.” The poor interaction between the housing rental market and the sales market caused by the shortage of rental demand and irrational purchasing behaviors has led to soaring house prices and imbalance between supply and demand that prevail in major cities in China. To gain a deeper understanding of public cognitive attitude toward decisions on owning and renting a house, this study divided the subjects into high and low impact groups based on the overall Confucian culture and four subdimensions. It attempts to take a cognitive neuroscience approach for assessing public stereotypes of housing consumption decision with different types based on the analysis of event-related potentials (ERPs). The results are as follows. First, overall, there is an obvious implicit stereotype of renting a house and explicit stereotype of owning a house among the public. Second, ERPs data show that descriptions of renting a house with positive adjectives could evoke more significant N400 responses. In other words, in the heuristic system, the public perceive that renting a house is restrictive, stressful, unhappy, and crisis. Data from subjective reports show that, after processing information in the analytic system, the public tend to think that owning a house is self-contained, restful, warm, and comfortable. Third, a more negative stereotype of renting a house exists in the high Confucian culture influence group (HIC) Group than in the low Confucian culture influence group (LIC) Group, and is more inclined to own a home. Fourth, under the Confucian culture sub-dimension, there are differences in housing consumption stereotypes between high and low groups in terms of extended family concept, group conformity, and crisis consciousness. Fifth, the moderating effect analysis found that perceived usefulness, trust in the rental market, and policy perception can be important factors in guiding public housing consumption stereotypes.

Neuropsychological and Neurophysiological Assessment in Different Phases of Bipolar Disorder.

Recent studies have shown that cognitive deficits are significant and pervasive even among remitted bipolar disorder patients. The aim of the current controlled study was to investigate the relationships between cognitive performances, symptom severity, and event-related potentials with regard to different episodes in bipolar patients. This study was conducted on a total of 60 patients diagnosed with bipolar disorder (20 depressive, 20 manic, and 20 in remission). The Frontal Assessment Battery and Stroop test were used for neuropsychological assessment. Event-related potentials were measured using frontal, central, and parietal EEG recordings, while Nihon-Kohden EMG-EP system was used. Delayed P300 latencies were observed in all phases of bipolar disorder when compared to the controls. There was a positive relationship between frontal, central P300 latencies, and Young Mania Rating Scale scores. A strong positive relationship was also observed between Young Mania Rating Scale scores and Stroop interference scores. A negative relationship was observed between Frontal Assessment Battery scores and frontal, central, and parietal N100 latencies and amplitudes in depressed patients. Consistent with these findings, there was a relationship between Hamilton Depression Rating Scale scores and N100 latencies. There was also a positive relationship between Stroop interference scores and central N200 latency, as well as frontal N200 and parietal N200 amplitudes, while a negative relationship was observed between Stroop total time scores and central N200 latency as well as parietal N200 amplitude in depressed patients. Study findings imply that depression episodes could be associated with decision-making autonomy and memory issues, while there is also a relationship between episodes of mania, impaired inhibitory control, and issues with selective attention. Moreover, these cognitive impairments might be included in the initial phases of processing observed in N100 responses in depression, while processing impairment could be pervasive in mania that results in P300 delays.

The neural processing of social norms in biculturals: The relation between cultural tightness and semantic processing

Perceptions of the appropriateness and inappropriateness of social norms across three ethnic groups in the U.S. were investigated using event-related potentials. N400 measures were elicited for appropriate versus inappropriate social scenarios from Asian American, Latinx, and European American participants along with self-reported perceptions of cultural tightness (Gelfand et al., 2011). As hypothesized, inappropriate scenarios elicited larger N400 responses compared to appropriate scenarios and the N400 was correlated with self-reported tightness in frontal electrodes. No differences across ethnic groups emerged in either self-reported tightness or in N400 response to norm deviations. Implications for norm adoption in bicultural individuals, replicability of previous findings, and culturally “embrained” processes of acculturation are discussed.

Examining the context benefit in older adults: A combined behavioral-electrophysiologic word identification study

When listening to degraded speech, listeners can use high-level semantic information to support recognition. The literature contains conflicting findings regarding older listeners' ability to benefit from semantic cues in recognizing speech, relative to younger listeners. Electrophysiologic (EEG) measures of lexical access (N400) often show that semantic context does not facilitate lexical access in older listeners; in contrast, auditory behavioral studies indicate that semantic context improves speech recognition in older listeners as much as or more than in younger listeners. Many behavioral studies of aging and the context benefit have employed signal degradation or alteration, whereas this stimulus manipulation has been absent in the EEG literature, a possible reason for the inconsistencies between studies. Here we compared the context benefit as a function of age and signal type, using EEG combined with behavioral measures. Non-native accent, a common form of signal alteration which many older adults report as a challenge in daily speech recognition, was utilized for testing. The stimuli included English sentences produced by native speakers of English and Spanish, containing target words differing in cloze probability. Listeners performed a word identification task while 32-channel cortical responses were recorded. Results show that older adults’ word identification performance was poorer in the low-predictability and non-native talker conditions than the younger adults', replicating earlier behavioral findings. However, older adults did not show reduction or delay in the average N400 response as compared to younger listeners, suggesting no age-related reduction in predictive processing capability. Potential sources for discrepancies in the prior literature are discussed.

Semantic systems are mentalistically activated for and by social partners

A recently discovered electrophysiological response, the social N400, suggests that we use our language system to track how social partners comprehend language. Listeners show an increased N400 response, when themselves not, only a communicative partner experiences a semantic incongruity. Does the N400 reflect purely semantic or mentalistic computations as well? Do we attribute language comprehension to communicative partners using our semantic systems? In five electrophysiological experiments we identified two subcomponents of the social N400. First, we manipulated the presence-absence of an Observer during object naming: the semantic memory system was activated by the presence of a social partner in addition to semantic predictions for the self. Next, we induced a false belief—and a consequent miscomprehension—in the Observer. Participants showed the social N400, over and above the social presence effect, to labels that were incongruent for the Observer, even though they were congruent for them. This effect appeared only if participants received explicit instructions to track the comprehension of the Observer. These findings suggest that the semantic systems of the brain are not merely sensitive to social information and contribute to the attribution of comprehension, but they appear to be mentalistic in nature.

EEG theta and N400 responses to congruent versus incongruent brand logos

Neuroimaging and behavioral studies have shown that brands convey meaning to consumers. To investigate the immediate reactions of the brain to brand logos, followed either by congruent or incongruent pictorial brand-related cues, can deepen understanding of the semantic processing of brands, and perhaps how consolidated the logo is in consumers’ minds. Participants were exposed to different brand-related image sets, that were either congruent (a match between brand-related images and brand logo) or incongruent (a mismatch between brand-related images and brand logo) while having their brain signals recorded. Event-related potential and EEG time–frequency domain features were extracted from the signals of the target image (brand logo). The results showed significantly larger N400 peak and relative theta power increase for incongruent compared to congruent logos, which could be attributed to an error-monitoring process. Thus, we argue that brands are encoded deeply in consumers’ minds, and cognitive processing of mismatched (vs matched) brand logos is more difficult, leading to greater error monitoring. The results were mostly consistent with previous studies investigating semantic incongruences in the linguistic field. Therefore, the error-monitoring process could be extended beyond linguistic forms, for example to images and brands.

Perceptive and affective impairments in emotive eye-region processing in alexithymia.

Alexithymia is characterized by impairments in emotion processing, frequently linked to facial expressions of emotion. The eye-region conveys information necessary for emotion processing. It has been demonstrated that alexithymia is associated with reduced attention to the eyes, but little is known regarding the cognitive and electrophysiological mechanisms underlying emotive eye-region processing in alexithymia. Here, we recorded behavioral and electrophysiological responses of individuals with alexithymia (ALEX; n = 25) and individuals without alexithymia (NonALEX; n = 23) while they viewed intact and eyeless faces with angry and sad expressions during a dual-target rapid serial visual presentation task. Results showed different eye-region focuses and differentiating N1 responses between intact and eyeless faces to anger and sadness in NonALEX, but not in ALEX, suggesting deficient perceptual processing of the eye-region in alexithymia. Reduced eye-region focus and smaller differences in frontal alpha asymmetry in response to sadness between intact and eyeless faces were observed in ALEX than NonALEX, indicative of impaired affective processing of the eye-region in alexithymia. These findings highlight perceptual and affective abnormalities of emotive eye-region processing in alexithymia. Our results contribute to understanding the neuropsychopathology of alexithymia and alexithymia-related disorders.

Level of Orthographic Knowledge Helps to Reveal Automatic Predictions in Visual Word Processing.

The brain generates predictions about visual word forms to support efficient reading. The “interactive account” suggests that the predictions in visual word processing can be strategic or automatic (non-strategic). Strategic predictions are frequently demonstrated in studies that manipulated task demands, however, few studies have investigated automatic predictions. Orthographic knowledge varies greatly among individuals and it offers a unique opportunity in revealing automatic predictions. The present study grouped the participants by level of orthographic knowledge and recorded EEGs in a non-linguistic color matching task. The visual word-selective N170 response was much stronger to pseudo than to real characters in participants with low orthographic knowledge, but not in those with high orthographic knowledge. Previous work on predictive coding has demonstrated that N170 is a good index for prediction errors, i.e., the mismatches between predictions and visual inputs. The present findings provide unambiguous evidence that automatic predictions modulate the early stage of visual word processing.

Abstract WMP93: Somatosensory Evoked Potentials Monitoring In Acute Ischemic Stroke (Promise) Study: A Biomarker Of Functional Recovery Prior To Mechanical Thrombectomy (clinicaltrials.gov: NCT04099615)

Hypothesis: Somatosensory evoked potentials (SEPs), as surrogate of cerebral blood flow, may give substantial additional predictive value to that provided by clinical and imaging factors and optimize the selection of patients benefiting from mechanical thrombectomy (MT) Methods: Bilateral median nerve SEPs were recorded before and continuously during MT in consecutive patients with AIS and anterior LVO. N20 response ipsilateral to the ischemic hemisphere was measured. The adjusted predictive value of the N20 on functional Independence (modified Rankin Scale score ≤2) after MT was analyzed by binary logistic regression and its predictive value on the full range of disability by ordinal logistic regression. We constructed different regression models with other clinical and imaging predictors at the pre- and in- hospital setting to determine the independent predictive power of N20 for a potential treatment decision-making Results: A total of 223 patients were recruited. A blinded reading of SEPs recordings identified presence of N20 in 110 (49.3%), absence in 58 (26%) and not assessable in 55 patients due to radiofrequency interferences. Prior to MT, N20 had positive predictive value (PPV) of 93% (95%CI, 0.8 to 0.98) and increased 10 fold the likelihood of good functional outcome at 7 days (adjusted OR, 9.9; 95%CI, 3.1-44.6). Receiver operating curves showed that N20 had a higher capacity to predict good functional outcome (AUC 0.82) than models constructed with pre-hospital (age, sex, serum glucose, median blood pressure, NIHSS; AUC 0.75) or in-hospital (NIHSS, ASPECTS; AUC 0.72) factors. During MT, N20 had PPV of 100% (95% CI, 0.85-1) and was the unique independent factor associated with functional independence (adjusted OR, 2.74; 95%CI, 1.90-4.29). Perfusion CT or MR was available in a subgroup of 116 patients. Baseline N20 showed a higher capacity to predict good functional outcome (n=168, AUC 0.71) compared with ischemic core (n=127, AUC 0.66), ischemic penumbra (Tmax>6) (n=116, AUC 0.54) and collateral status (n=191, AUC 0.61) Conclusions: SEPs monitoring is a fast and bedside technique that could complement current clinical factors in terms of increasing the eligibility of AIS patients for MT and improving prognosis.

The effects of unpredictability and negative affect on perception and neural gating in different interoceptive modalities

Breathlessness and pain frequently co-occur in chronic conditions, and their unpredictability is often reported to amplify perception and negative affect (NA), however any common neural mechanisms remain largely unexplored. This study examined the effects of (unpredictable) bodily threat on perception and neural gating of respiratory and somatosensory stimuli. Healthy adults (N = 51) experienced brief paired inspiratory occlusions and electrocutaneous stimuli, with their neural activity monitored via electroencephalography. Neural gating was measured as a ratio of the N1 response to the second relative to the first stimulus in a pair. In 4/6 blocks, threatening stimulation, in form of additional loaded breaths or electrocutaneous pulses, was presented predictably or unpredictably. Participants reported: perceived intensity and unpleasantness of all stimuli, fear, trait NA and intolerance of uncertainty (IU). Threatening stimulation increased perception, fear, and N1 amplitudes, without affecting neural gating. There was no group effect of unpredictability, though interactions were found with NA and IU. Cross-modal correlations revealed significant baseline relationships in neural gating and perception, though not in their modulation by threat. The present findings demonstrate that respiratory and somatosensory modalities relate in baseline perception and neural gating, and exhibit similar modulation effects by unpleasant stimulation. Further research is encouraged to elucidate the underlying mechanisms of these relationships, and the potential interactions with stimulus unpredictability.

The resolution stage, not the incongruity detection stage, is related to the subjective feeling of humor: An ERP study using Japanese nazokake puns

This study examined the relationship between two cognitive stages of humor processing (i.e., detecting incongruity and resolving it) and the subjective feeling of humor, using event-related brain potentials (ERPs). Unlike traditional English jokes, Japanese nazokake puns have a structure in which the detection of incongruity and the resolution of it are separated, which enabled this study to observe the ERPs for these two stages independently. In addition, to investigate how the cognitive stages work when people subjectively find a pun funny, the ERPs elicited by funny and unfunny puns, categorized according to participants’ subjective ratings, were compared. This subjective feeling has not received enough attention in previous literature. The results showed that N400 and P600 responses occurred during the incongruity detection stage and the resolution stage, respectively. Furthermore, funny puns enlarged the P600 amplitude compared to unfunny ones, but the N400 amplitude did not significantly differ between the funniness categories. These findings indicate that the resolution stage of humor processing is related to the subjective feeling of humor, rather than the incongruity detection stage.

The Effect of Different Noise Maskers and Speech Understanding in Noise on Auditory Cortical N1 Response

The Effect of Different Noise Maskers and Speech Understanding in Noise on Auditory Cortical N1 Response

Comparing Clinically Applicable Behavioral and Electrophysiological Measures of Speech Detection, Discrimination, and Comprehension.

Effective communication requires good speech perception abilities. Speech perception can be assessed with behavioral and electrophysiological methods. Relating these two types of measures to each other can provide a basis for new clinical tests. In audiological practice, speech detection and discrimination are routinely assessed, whereas comprehension-related aspects are ignored. The current study compared behavioral and electrophysiological measures of speech detection, discrimination, and comprehension. Thirty young normal-hearing native Danish speakers participated. All measurements were carried out with digits and stationary speech-shaped noise as the stimuli. The behavioral measures included speech detection thresholds (SDTs), speech recognition thresholds (SRTs), and speech comprehension scores (i.e., response times). For the electrophysiological measures, multichannel electroencephalography (EEG) recordings were performed. N100 and P300 responses were evoked using an active auditory oddball paradigm. N400 and Late Positive Complex (LPC) responses were evoked using a paradigm based on congruent and incongruent digit triplets, with the digits presented either all acoustically or first visually (digits 1-2) and then acoustically (digit 3). While no correlations between the SDTs and SRTs and the N100 and P300 responses were found, the response times were correlated with the EEG responses to the congruent and incongruent triplets. Furthermore, significant differences between the response times (but not EEG responses) obtained with auditory and visual-then-auditory stimulus presentation were observed. This pattern of results could reflect a faster recall mechanism when the first two digits are presented visually rather than acoustically. The visual-then-auditory condition may facilitate the assessment of comprehension-related processes in hard-of-hearing individuals.

Age and Vocabulary Knowledge Differentially Influence the N400 and Theta Responses During Semantic Retrieval

Age and Vocabulary Knowledge Differentially Influence the N400 and Theta Responses During Semantic Retrieval

The neural pattern of intuitive and analytical processes in the subliminal environment: N2 responses on the embedded Chinese character task

Dual process theory proposes that there are two different types of human thinking: an intuitive process and an analytical process. However, if these two types of thinking could maintain their characteristics in the subliminal environment, further exploration of their relationship is required. This study used the Embedded Chinese Character Task (ECCT) with event-related potentials to investigate the behavioral and neural patterns of the intuitive and analytical processes in the subliminal environment. In this task, one Chinese character (target character) was extracted from another character (test character) with problem solving that required either an intuitive process (in which the two characters were spatially separated or adjacent) or analytical process (in which the target characters were embedded in the test characters). Participants were asked to judge whether the target character was included or excluded from the test character in the subliminal environment. Results showed that a difference in reaction time occurred between inclusion and exclusion only in the analytical materials, but there was a difference in N2 between the inclusion and exclusion conditions in both intuitive and analytical materials, indicating that participants preferred to choose intuitive processing to solve intuitive and analytical problems in an unconscious environment. These findings support the traditional dual process theory, which states that the intuitive process is unconscious and effortless, while the analytical process may perform like an intuitive process in a subliminal environment.

Lower Cognitive Set Shifting Ability Is Associated With Stiffer Balance Recovery Behavior and Larger Perturbation-Evoked Cortical Responses in Older Adults.

The mechanisms underlying associations between cognitive set shifting impairments and balance dysfunction are unclear. Cognitive set shifting refers to the ability to flexibly adjust behavior to changes in task rules or contexts, which could be involved in flexibly adjusting balance recovery behavior to different contexts, such as the direction the body is falling. Prior studies found associations between cognitive set shifting impairments and severe balance dysfunction in populations experiencing frequent falls. The objective of this study was to test whether cognitive set shifting ability is expressed in successful balance recovery behavior in older adults with high clinical balance ability (N = 19, 71 ± 7 years, 6 female). We measured cognitive set shifting ability using the Trail Making Test and clinical balance ability using the miniBESTest. For most participants, cognitive set shifting performance (Trail Making Test B-A = 37 ± 20 s) was faster than normative averages (46 s for comparable age and education levels), and balance ability scores (miniBESTest = 25 ± 2/28) were above the threshold for fall risk (23 for people between 70 and 80 years). Reactive balance recovery in response to support-surface translations in anterior and posterior directions was assessed in terms of body motion, muscle activity, and brain activity. Across participants, lower cognitive set shifting ability was associated with smaller peak center of mass displacement during balance recovery, lower directional specificity of late phase balance-correcting muscle activity (i.e., greater antagonist muscle activity 200–300 ms after perturbation onset), and larger cortical N1 responses (100–200 ms). None of these measures were associated with clinical balance ability. Our results suggest that cognitive set shifting ability is expressed in balance recovery behavior even in the absence of profound clinical balance disability. Specifically, our results suggest that lower flexibility in cognitive task performance is associated with lower ability to incorporate the directional context into the cortically mediated later phase of the motor response. The resulting antagonist activity and stiffer balance behavior may help explain associations between cognitive set shifting impairments and frequent falls.