Sex Differences in Semantic Processing: Event-Related Brain Potentials Distinguish between Lower and Higher Order Semantic Analysis during Word Reading

The inter-related effects of alcohol use severity and sleep deficiency on semantic processing in young adults

BACKGROUND

Both alcohol misuse and sleep deficiency are associated with deficits in semantic processing. However, alcohol misuse and sleep deficiency are frequently comorbid and their inter-related effects on semantic processing as well as the underlying neural mechanisms remain to be investigated.

METHODS

We curated the Human Connectome Project data of 973 young adults (508 women) to examine the neural correlates of semantic processing in link with the severity of alcohol use and sleep deficiency. The latter were each evaluated using the first principal component (PC1) of principal component analysis of all drinking metrics and the Pittsburgh Sleep Quality Index (PSQI). We employed path modeling to elucidate the interplay among clinical, behavioral, and neural variables.

RESULTS

Among women, we observed a significant negative correlation between the left precentral gyrus (PCG) and PSQI scores. Mediation analysis revealed that the left PCG activity fully mediated the relationship between PSQI scores and word comprehension in language tasks. In women alone also, the right middle frontal gyrus (MFG) exhibited a significant negative correlation with PC1. The best path model illustrated the associations among PC1, PSQI scores, PCG activity, and MFG activation during semantic processing in women.

CONCLUSIONS

Alcohol misuse may lead to reduced MFG activation while sleep deficiency hinder semantic processing by suppressing PCG activity in women. The pathway model underscores the influence of sleep quality and alcohol consumption severity on semantic processing in women, suggesting that sex differences in these effects need to be further investigated.

Effects of sleep deprivation on language-related brain functional connectivity: differences by gender and age

Sleep deprivation (SD) negatively affects many cognitive functions, such as language performance. However, what remains unclear is whether and how SD affects the language-related brain network based on gender and age differences. The current study of 86 healthy adults used resting-state functional magnetic resonance imaging (rs-fMRI) to measure language-related functional connectivity after full sleep or partial SD. Gender and age differences in functional connectivity were assessed across four linguistic aspects: phonetics, morphology, semantics, and syntax. The results showed that SD can affect the connectivity status of language-related brain networks, especially syntax-related networks. Furthermore, the influence of SD on the functional connectivity in language-related networks differed between male and female groups, and between younger and older groups. Specifically, there were gender differences in the temporal association cortex and age differences in the parietal association cortex, during full sleep versus partial SD. These findings highlight changes in the brain's functional connectivity in response to SD as a potential source of gender and age differences in brain function.

SORL1 rs1699102 Moderates the Effect of Sex on Language Network

BACKGROUND

Language ability differs between the sexes. However, it is unclear how this sex difference is moderated by genetic factors and how the brain interacts with genetics to support this specific language capacity. Previous studies have demonstrated that the sorting protein-related receptor (SORL1) polymorphism influences cognitive function and brain structure differently in males and females and is associated with Alzheimer's disease risk.

OBJECTIVE

The aim of this study was to investigate the effects of sex and the SORL1 rs1699102 (CC versus T carriers) genotype on language.

METHODS

103 non-demented Chinese older adults from Beijing Aging Brain Rejuvenation Initiative (BABRI) database were included in this study. Participants completed language tests, T1-weighted structural magnetic resonance imaging (MRI) and resting-state functional MRI. Language test performance, gray matter volume, and network connections were compared between genotype and sex groups.

RESULTS

The rs1699102 polymorphism moderated the effects of sex on language performance, with the female having reversed language advantages in T carriers. The T allele carriers had lower gray matter volume in the left precentral gyrus. The effect of sex on language network connections was moderated by rs1699102; male CC homozygotes and female T carriers had higher internetwork connections, which were negatively correlated with language performance.

CONCLUSION

These results suggest that SORL1 moderates the effects of sex on language, with T being a risk allele, especially in females. Our findings underscore the importance of considering the influence of genetic factors when examining sex effects.

Effects of Healthy Aging and Gender on the Electrophysiological Correlates of Semantic Sentence Comprehension: The Development of Dutch Normative Data

PURPOSE

The clinical use of event-related potentials in patients with language disorders is increasingly acknowledged. For this purpose, normative data should be available. Within this context, healthy aging and gender effects on the electrophysiological correlates of semantic sentence comprehension were investigated.

METHOD

One hundred and ten healthy subjects (55 men and 55 women), divided among three age groups (young, middle aged, and elderly), performed a semantic sentence congruity task in the visual modality during electroencephalographic recording.

RESULTS

The early visual complex was affected by increasing age as shown by smaller P2 amplitudes in the elderly compared to the young. Moreover, the N400 effect in the elderly was smaller than in the young and was delayed compared to latency measures in both middle-aged and young subjects. The topography of age-related amplitude changes of the N400 effect appeared to be gender specific. The late positive complex effect was increased at frontal electrode sites from middle age on, but this was not statistically significant. No gender effects were detected regarding the early P1, N1, and P2, or the late positive complex effect.

CONCLUSION

Especially aging effects were found during semantic sentence comprehension, and this from the level of perceptual processing on. Normative data are now available for clinical use.

Unisensory and Multisensory Stroop Effects Modulate Gender Differences in Verbal and Nonverbal Emotion Perception

Purpose This study aimed to examine the Stroop effects of verbal and nonverbal cues and their relative impacts on gender differences in unisensory and multisensory emotion perception. Method Experiment 1 investigated how well 88 normal Chinese adults (43 women and 45 men) could identify emotions conveyed through face, prosody and semantics as three independent channels. Experiments 2 and 3 further explored gender differences during multisensory integration of emotion through a cross-channel (prosody-semantics) and a cross-modal (face-prosody-semantics) Stroop task, respectively, in which 78 participants (41 women and 37 men) were asked to selectively attend to one of the two or three communication channels. Results The integration of accuracy and reaction time data indicated that paralinguistic cues (i.e., face and prosody) of emotions were consistently more salient than linguistic ones (i.e., semantics) throughout the study. Additionally, women demonstrated advantages in processing all three types of emotional signals in the unisensory task, but only preserved their strengths in paralinguistic processing and showed greater Stroop effects of nonverbal cues on verbal ones during multisensory perception. Conclusions These findings demonstrate clear gender differences in verbal and nonverbal emotion perception that are modulated by sensory channels, which have important theoretical and practical implications. Supplemental Material https://doi.org/10.23641/asha.16435599.

Contrastive intonation effects on word recall for information-structural alternatives across the sexes

Focus highlights the fact that contextual alternatives are relevant for the interpretation of an utterance. For example, if someone says: “The meeting is on TUESDAY,” with focus marked by a pitch accent on “Tuesday,” the speaker might want to correct the assumption that the meeting is on Monday (an alternative date). Intonation as one way to signal focus was manipulated in a delayed-recall paradigm. Recall of contextual alternatives was tested in a condition where a set of alternatives was evoked by contrastive intonation. A control condition used intonation contours reported for broad focus in German. It was hypothesized that contrastive intonation improves recall, just as focus-sensitive particles (e.g., ‘only’) do, compared to sentences without such particles. Participants listened to short texts introducing a list of three elements from taxonomic categories. One of the three elements was re-mentioned in a subsequent critical sentence, realized with either a broad (H+!H*) or with a contrastive intonation contour (L+H*). Cued recall of the list elements was tested block-wise. Results show that contrastive intonation enhances recall for focus alternatives. In addition, it was found that the observed recall benefit is predominantly driven by females. The results support the assumption that contextual alternatives are better encoded in memory irrespective of whether focus is expressed prosodically or by a focus-sensitive particle. The results further show that females are more sensitive to pragmatic information conveyed through prosody than males.

Gender-dependent variations in optical illusions: evidence from N400 waveforms

OBJECTIVE

The cognitive mechanisms (especially the gender-related ones) underlying optical illusion processing remain elusive. Since the N400 component of event-related potentials (ERPs) is an index of the semantic integration of information processing tasks, the present study focuses on gender-related differences in N400 waveforms elicited during the reasoning process applied to reach a valid conclusion of optical illusions engaging working memory (WM).

APPROACH

Fifty-one healthy participants (28 males, age = 34.25 years ± 10.25, years of education = 16.00 years ± 1.78; and 23 females, age = 33.43 ± 7.93, years of education = 15.56 ± 1.82) were measured. The N400 ERP component was evoked by 39 optical illusions adjusted to induce WM. We compared brain activation patterns while participants maintained conclusions of the optical illusions in WM. The N400 of ERPs was recorded during the WM phase, during which participants were required to draw a logical conclusion regarding the correctness of the optical illusions.

MAIN RESULTS

Analysis revealed that females compared to males exhibited significantly increased N400 amplitudes located at parietal and occipital sites, whereas males exhibited significantly higher N400 amplitudes located at frontal areas. Furthermore, females compared to males demonstrated significantly prolonged latencies of the N400 component located at right frontotemporal abductions.

SIGNIFICANCE

These results suggest that coupling of optical illusions with WM engages distinct gender-related variations of brain semantic processing as reflected by the N400 ERP component. Based on the dual process account, our study gives support to the notion that women tend to employ a more deliberate and slower semantic reasoning than the men who tend to employ an automatic and fast one. Topographically, within the network sub-serving the semantic operation, the posterior brain areas responsible for sensorimotor integration-related processes elicit a greater brain activation among females while the anterior brain areas responsible for control and storage/retrieval operation elicit a greater brain activation among males.

Design and evaluation of the effectiveness of a corpus of congruent and incongruent English sentences for the study of event related potentials

OBJECTIVE

To design and evaluate the effectiveness of a stimulus material in eliciting the N400 event related potential (ERP).

DESIGN

A set of 700 semantically congruent and incongruent sentences was developed in accordance with current linguistic norms, and validated with an electroencephalography (EEG) study, in which the influence of age and gender on the N400 ERP magnitude was analysed.

STUDY SAMPLE

Forty-five normal-hearing subjects (19-57 years, 21 females) participated in the EEG study.

RESULTS

The stimulus material used in the EEG study elicited a robust N400 ERP, with a morphology consistent with the literature. Results also showed no statistically significant effect of age or gender on the N400 magnitude.

CONCLUSIONS

The material presented in this paper constitutes the largest complete stimulus set suitable for both auditory and text-based N400 experiments. This material may help facilitate the efficient implementation of future N400 ERP studies, as well as promote standardisation and consistency across studies.

Sex and gender differences and biases in artificial intelligence for biomedicine and healthcare

Precision Medicine implies a deep understanding of inter-individual differences in health and disease that are due to genetic and environmental factors. To acquire such understanding there is a need for the implementation of different types of technologies based on artificial intelligence (AI) that enable the identification of biomedically relevant patterns, facilitating progress towards individually tailored preventative and therapeutic interventions. Despite the significant scientific advances achieved so far, most of the currently used biomedical AI technologies do not account for bias detection. Furthermore, the design of the majority of algorithms ignore the sex and gender dimension and its contribution to health and disease differences among individuals. Failure in accounting for these differences will generate sub-optimal results and produce mistakes as well as discriminatory outcomes. In this review we examine the current sex and gender gaps in a subset of biomedical technologies used in relation to Precision Medicine. In addition, we provide recommendations to optimize their utilization to improve the global health and disease landscape and decrease inequalities.

Sex Differences in Functional Brain Networks for Language

Men and women process language differently, but how the brain functions to support this difference is poorly understood. A few studies reported sex influences on brain activation for language, whereas others failed to detect the difference at the functional level. Recent advances of brain network analysis have shown great promise in picking up brain connectivity differences between sexes, leading us to hypothesize that the functional connections among distinct brain regions for language may differ in males and females. To test this hypothesis, we scanned 58 participants’ brain activities (28 males and 30 females) in a semantic decision task using functional magnetic resonance imaging. We found marked sex differences in dynamic interactions among language regions, as well as in functional segregation and integration of brain networks during language processing. The brain network differences were further supported by a machine learning analysis that accurately discriminated males from females using the multivariate patterns of functional connectivity. The sex-specific functional brain connectivity may constitute an essential neural basis for the long-held notion that men and women process language in different ways. Our finding also provides important implications for sex differences in the prevalence of language disorders, such as dyslexia and stuttering.

Sex, Age, and Handedness Modulate the Neural Correlates of Active Learning

BACKGROUND

Self-generation of material compared to passive learning results in mproved memory performance; this may be related to recruitment of a fronto-temporal encoding network. Using a verbal paired-associate learning fMRI task, we examined the effects of sex, age, and handedness on the neural correlates of self-generation.

METHODS

Data from 174 healthy English-speaking participants (78M, 56 atypically handed; ages 19-76) were preprocessed using AFNI and FSL. Independent component analysis was conducted using GIFT (Group ICA fMRI Toolbox). Forty-one independent components were temporally sorted by task time series. Retaining correlations (r > 0.25) resulted in three task-positive ("generate") and three task-negative ("read") components. Using participants' back-projected components, we evaluated the effects of sex, handedness, and aging on activation lateralization and localization in task-relevant networks with two-sample t-tests. Further, we examined the linear relationship between sex and neuroimaging data with multiple regression, covarying for scanner, age, and handedness.

RESULTS

Task-positive components identified using ICA revealed a fronto-parietal network involved with self-generation, while task-negative components reflecting passive reading showed temporo-occipital involvement. Compared to older adults, younger adults exhibited greater task-positive involvement of the left inferior frontal gyrus and insula, whereas older adults exhibited reduced prefrontal lateralization. Greater involvement of the left angular gyrus in task-positive encoding networks among right-handed individuals suggests the reliance on left dominant semantic processing areas may be modulated by handedness. Sex effects on task-related encoding networks while controlling for age and handedness suggest increased right hemisphere recruitment among males compared to females, specifically in the paracentral lobe during self-generation and the suparmarginal gyrus during passive reading.

IMPLICATIONS

Identified neuroimaging differences suggest that sex, age, and handedness are factors in the differential recruitment of encoding network regions for both passive and active learning.

Historic Approaches to Sonic Encounter at the Berlin Wall Memorial

Investigations of historic soundscapes must analyze and place results within a complex framework of contemporary and past contexts. However, the conscious use and presentation of historic built environments are factors that require more deliberate attention in historic soundscape analysis. The following paper presents a multimodal research methodology and promising preliminary results from a study at the Berlin Wall Memorial in Berlin, Germany. Here, the historic context from the Wall’s recent past is presented within the surroundings of the contemporary unified capital city. The study approached the past soundscape and present site by combining historic and current-conditions research, linking archival research, conditions assessments via binaural recording and psychoacoustics analysis tools, and soundscape surveys rooted in standardized soundscape research practices. In so doing, archival textual and pictorial sources provided a rich source of primary information integrated within the study and are suggested as a resource for similar inquiries elsewhere. The investigation identified concerns specific to heritage sites that require critical consideration for historic soundscape research of the recent past—survey-participant composition and the problematized use of typical descriptors in soundscape surveys are the two concerns that are discussed. Some standardized soundscape terminology and research methodologies were found to be insufficient in historic contexts. Initial qualitative results from the research are presented as a proof of concept for the research approach with signposts for future analysis and developments.

The impact of spoken action words on performance in a cross-modal oddball task

In this study a cross-modal oddball task was employed to study the effect that words spoken either non-urgently or urgently would have on a digit categorization task and if women would exhibit greater behavioral inhibitory control. The words were unrelated to the task itself, but related to the action required to complete the task. Forty participants (21 women) conducted a computerized categorization task while exposed to a sinewave tone as a standard stimulus (75% of the trials) or a to-be ignored word (press, stop) spoken either non-urgently or urgently as unexpected auditory deviant stimulus (6.25% trials for each category). Urgent words had sharp intonation and an average fundamental frequency (F₀) ranging from 191.9 (stop) to 204.6 (press) Hz. Non-urgent words had low intonation with average F₀ ranging from 103.9.9 (stop) to 120.3 (press) Hz. As expected, deviant distraction and longer response times were found by exposure to the word stop, but deviant distraction was not found to be significant with the word press or due to intonation. While the results showed that women had in general longer reaction times, there were no gender differences found related to the deviant distraction caused by word or intonation. The present results do not support the hypothesis that women have greater behavioral inhibitory control, but there was evidence that the meaning of the word could influence response times.

Emotional context restores cortical prediction error responses in schizophrenia

The mismatch negativity (MMN) deficit in schizophrenia is a consistently replicated finding and is considered a potential biomarker. From the cognitive neuroscience perspective, MMN represents a cortical correlate of the prediction error, a fundamental computational operator that may be at the core of various cognitive and clinical deficits observed in schizophrenia. The impact of emotion on cognitive processes in schizophrenia is insufficiently understood, and its impact on basic operators of cortical computation is largely unknown. In the visual domain, the facial expression mismatch negativity (EMMN) offers an opportunity to investigate basic computational operators in purely cognitive and in emotional contexts. In this study, we asked whether emotional context enhances cortical prediction error responses in patients with schizophrenia, as is the case in normal subjects. Therefore, seventeen patients with schizophrenia and eighteen controls completed a visual sequence oddball task, which allows for directly comparing MMN components evoked by deviants with high, intermediate and low emotional engagement. Interestingly, patients with schizophrenia showed pronounced deficits in response to neutral stimuli, but almost normal responses to emotional stimuli. The dissociation between impaired MMN and normal EMMN suggests that emotional context not only enhances, but restores cortical prediction error responses in patients with schizophrenia to near-normal levels. Our results show that emotional processing in schizophrenia is not necessarily defect; more likely, emotional processing heterogeneously impacts on cognition in schizophrenia. In fact, this study suggests that emotional context may even compensate for cognitive deficits in schizophrenia that are, in a different sensory domain, discussed as biomarkers.

The Influence of Sex Information on Gender Word Processing

Three different tasks (word repetition, lexical decision, and gender decision) were designed to explore the impact of the sex clues (sex of the speaker, sex of the addressee) and the type of gender (semantic, arbitrary) on the processing of isolated Spanish gendered words. The findings showed that the grammatical gender feature was accessed when no mandatory attentional focus was required. In addition, the results indicated that the participants organize information according to their own sex role, which provides more salience to the words that match in grammatical gender with their own sex role representation, even when the gender assignment is arbitrary. Finally, the sex of the speaker biased the lexical access and the grammatical gender selection, serving as a semantic prime when the two dimensions have a congruent relationship. Furthermore, the masculine form serves as the generic gender representing both male and female figures.

The relationship between semantic access and introspective awareness

There have long been speculations about the relationship between consciousness and language. This study aimed to determine whether an individual's level of introspective awareness, based on self-report, relates to accessibility of their semantic system as evaluated by the N400. Thirty-five university students completed the study. All were right-handed, with normal or corrected-to-normal vision, without known neurological or psychological health issues. They first performed on a lexical decision task while their brain electrophysiological responses were recorded. Then, they provided assessment ratings about their levels of introspective awareness. Analysis revealed moderate to strong correlations (Pearson's rs = 0.49-0.62) between awareness self-ratings and ease of semantic access as indexed by the N400. Correlation between the self-report measure and the objective neurophysiological measure suggests that subjective assessment of awareness may deserve more credibility, which in addition to reflecting subjective perception and evaluation about one's own higher order mental functioning, may also interact with the neurophysiological processes contributive and subject to such awareness. Implications for future research on the role of semantic network in the mechanism of introspective awareness are discussed.

Sex Differences in Categorical Adaptation for Faces and Chinese Characters during Early Perceptual Processing

Previous event-related potential studies support sex differences in the N170 response during face and word processing; however, it remains unclear whether N170 categorical adaptation for faces and words is different between women and men. Using an adaptation paradigm, in which an adaptor and subsequent test stimulus are presented during each trial, the present study investigated N170 categorical adaptation for faces and Chinese characters in both women and men. The results demonstrated that the N170 amplitude elicited by test stimuli in within-category condition was lower than in control category condition, and this was observed during both face and Chinese character processing in women and men. In addition, we found that men have greater N170 categorical adaptation for face and word processing than women. There was also a significant correlation between N170 categorical adaptation indices for face and Chinese character processing in men, which did not occur in women. These findings suggest that men and women process repeated faces or words differently.

Minho Affective Sentences (MAS): Probing the roles of sex, mood, and empathy in affective ratings of verbal stimuli

During social communication, words and sentences play a critical role in the expression of emotional meaning. The Minho Affective Sentences (MAS) were developed to respond to the lack of a standardized sentence battery with normative affective ratings: 192 neutral, positive, and negative declarative sentences were strictly controlled for psycholinguistic variables such as numbers of words and letters and per-million word frequency. The sentences were designed to represent examples of each of the five basic emotions (anger, sadness, disgust, fear, and happiness) and of neutral situations. These sentences were presented to 536 participants who rated the stimuli using both dimensional and categorical measures of emotions. Sex differences were also explored. Additionally, we probed how personality, empathy, and mood from a subset of 40 participants modulated the affective ratings. Our results confirmed that the MAS affective norms are valid measures to guide the selection of stimuli for experimental studies of emotion. The combination of dimensional and categorical ratings provided a more fine-grained characterization of the affective properties of the sentences. Moreover, the affective ratings of positive and negative sentences were not only modulated by participants' sex, but also by individual differences in empathy and mood state. Together, our results indicate that, in their quest to reveal the neurofunctional underpinnings of verbal emotional processing, researchers should consider not only the role of sex, but also of interindividual differences in empathy and mood states, in responses to the emotional meaning of sentences.

Tell me sweet little lies: An event-related potentials study on the processing of social lies

In reading tasks, words that convey a false statement elicit an enhanced N400 brainwave response, relative to words that convey a true statement. N400 amplitude reductions are generally linked to the online expectancy of upcoming words in discourse. White lies, contrary to false statements, may not be unexpected in social scenarios. We used the event-related potential (ERP) technique to determine whether there is an impact of social context on sentence processing. We measured ERP responses to target words that either conveyed a social "white" lie or a socially impolite blunt truth, relative to semantic violations. Word expectancy was controlled for by equating the cloze probabilities of white lying and blunt true targets, as measured in previous paper-and-pencil tests. We obtained a classic semantic violation effect (a larger N400 for semantic incongruities relative to sense making statements). White lies, in contrast to false statements, did not enhance the amplitude of the N400 component. Interestingly, blunt true statements yielded both a late frontal positivity and an N400 response in those scenarios particularly biased to white lying. Thus, white lies do not interfere with online semantic processing, and they do not engage further reanalysis processes, which are typically indexed by subsequent late positivity ERP effects. Instead, an N400 and a late frontal positivity obtained in response to blunt true statements indicate that they were treated as unexpected events. In conclusion, unwritten rules of social communicative behavior influence the electrical brain response to locally coherent but socially inappropriate statements.

Sex Differences in Neurophysiological Activation Patterns During Phonological Input Processing: An Influencing Factor for Normative Data

In the context of neurophysiological normative data, it has been established that aging has a significant impact on neurophysiological correlates of auditory phonological input processes, such as phoneme discrimination (PD) and word recognition (WR). Besides age, sex is another demographic factor that influences several language processes. We aimed to disentangle whether sex has a similar effect on PD and WR. Event-related potentials (ERPs) were recorded in 20 men and 24 women. During PD, three phonemic contrasts (place and manner of articulation and voicing) were compared using the attentive P300 and pre-attentive Mismatch Negativity. To investigate WR, real words were contrasted with pseudowords in a pre-attentive oddball task. Women demonstrated a larger sensitivity to spectrotemporal differences, as evidenced by larger P300 responses to the place of articulation (PoA) contrast and larger P300 and MMN responses than men in PoA-based PD. Men did not display such sensitivity. Attention played an important role, considering that women needed more attentional resources to differentiate between PoA and the other phonemic contrasts. During WR, pseudowords evoked larger amplitudes already 100 ms post-stimulus independent of sex. However, women had decreased P200 latencies, but longer N400 latencies in response to pseudowords, whereas men showed increased N400 latencies compared to women in response to real words. The current results demonstrate significant sex-related influences on phonological input processes. Therefore, existing neurophysiological normative data for age should be complemented for the factor sex.

The effects of gender and self-insight on early semantic processing

This event-related potential (ERP) study explored individual differences associated with gender and level of self-insight in early semantic processing. Forty-eight Chinese native speakers completed a semantic judgment task with three different categories of words: abstract neutral words (e.g., logic, effect), concrete neutral words (e.g., teapot, table), and emotion words (e.g., despair, guilt). They then assessed their levels of self-insight. Results showed that women engaged in greater processing than did men. Gender differences also manifested in the relationship between level of self-insight and word processing. For women, level of self-insight was associated with level of semantic activation for emotion words and abstract neutral words, but not for concrete neutral words. For men, level of self-insight was related to processing speed, particularly in response to abstract and concrete neutral words. These findings provide electrophysiological evidence for the effects of gender and self-insight on semantic processing and highlight the need to take into consideration subject variables in related research.

From episodic to habitual prospective memory: ERP-evidence for a linear transition

Performing a prospective memory task repeatedly changes the nature of the task from episodic to habitual. The goal of the present study was to investigate the neural basis of this transition. In two experiments, we contrasted event-related potentials (ERPs) evoked by correct responses to prospective memory targets in the first, more episodic part of the experiment with those of the second, more habitual part of the experiment. Specifically, we tested whether the early, middle, or late ERP-components, which are thought to reflect cue detection, retrieval of the intention, and post-retrieval processes, respectively, would be changed by routinely performing the prospective memory task. The results showed a differential ERP effect in the middle time window (450–650 ms post-stimulus). Source localization using low resolution brain electromagnetic tomography analysis suggests that the transition was accompanied by an increase of activation in the posterior parietal and occipital cortex. These findings indicate that habitual prospective memory involves retrieval processes guided more strongly by parietal brain structures. In brief, the study demonstrates that episodic and habitual prospective memory tasks recruit different brain areas.

Semantic network disconnection in formal thought disorder

BACKGROUND

Structural and functional findings in schizophrenic patients with formal thought disorder (FTD) show abnormalities within left-side semantic areas. The present study investigate the network function of the involved brain regions as a function of FTD severity.

METHODS

We examined a group of 16 schizophrenia patients differing in FTD, but not in overall symptom severity, and 18 matched healthy controls. A passive word reading paradigm was applied during functional MRI (fMRI). A concatenated independent component analysis approach separated the fMRI signal into independent components, and spatial similarity was used to estimate the individual differences in spatial configuration of networks.

RESULTS

The semantic network was identified for both groups encompassing structures of the left inferior frontal gyrus, the left angular gyrus and the left middle temporal gyrus. The differences between the semantic networks of patients and controls increased with increasing severity of FTD. This difference was due to a decreasing contribution of the left inferior frontal gyrus (Brodmann area 45 and 47).

CONCLUSION

Severity of FTD was correlated with a disruption of the left semantic network in schizophrenic patients. We suggest that FTD is a consequence of a frontal-parietal/temporal disconnection due to a complex interaction between structural and functional abnormalities within the left semantic network.

Gender differences on the semantic flanker task using transposed-letter target words

Previous research has demonstrated that men and women are differentially influenced by irrelevant distractors. Other lines of evidence have suggested that increasing the perceptual load of a task reduces distractor interference for participants generally. The present study examined these effects using a semantic version of the flanker task; participants made speeded responses to category target words that were flanked by irrelevant distractors. The response mapping between the target and flanker words was either congruent (mapped to the same motor response) or incongruent (target word mapped to a different motor response to that of the flankers). Target words were presented either normally (e.g., table: low perceptual load) or with the beginning letters transposed (e.g., atble: high perceptual load). The results revealed that women showed a larger congruency effect than men but this was not due to greater interference on incongruent trials. While men and women made faster responses to normal than to transposed target words, this was similar in magnitude. The magnitude of the flanker effect for normal and transposed target words was significantly correlated in men but not in women. These findings are consistent with the view that women may process target words to a deeper level than men and therefore may engage in more conflict monitoring then men.

Resting-state functional connectivity patterns predict Chinese word reading competency

Resting-state functional connectivity (RSFC) offers a novel approach to reveal the temporal synchronization of functionally related brain regions. Recent studies have identified several RSFCs whose strength was associated with reading competence in alphabetic languages. In the present study, we examined the role of intrinsic functional relations for reading a non-alphabetic language – Chinese – by correlating RSFC maps of nine Chinese reading-related seed regions and reaction time in the single-character reading task. We found that Chinese reading efficiency was positively correlated with the connection between left inferior occipital gyrus and left superior parietal lobule, between right posterior fusiform gyrus and right superior parietal lobule, and between left inferior temporal gyrus and left inferior parietal lobule. These results could not be attributed to inter-individual differences arising from the peripheral processes of the reading task such as visual input detection and articulation. The observed RSFC-reading correlation relationships are discussed in the framework of Chinese character reading, including visuospatial analyses and semantic/phonological processes.

Depth of Conceptual Knowledge Modulates Visual Processes during Word Reading

Recent evidence suggests that conceptual knowledge modulates early visual stages of object recognition. The present study investigated whether similar modulations can be observed also for the recognition of object names, that is, for symbolic representations with only arbitrary relationships between their visual features and the corresponding conceptual knowledge. In a learning paradigm, we manipulated the amount of information provided about initially unfamiliar visual objects while controlling for perceptual stimulus properties and exposure. In a subsequent test session with electroencephalographic recordings, participants performed several tasks on either the objects or their written names. For objects as well as names, knowledge effects were observed as early as about 120 msec in the P1 component of the ERP, reflecting perceptual processing in extrastriate visual cortex. These knowledge-dependent modulations of early stages of visual word recognition suggest that information about word meanings may modulate the perception of arbitrarily related visual features surprisingly early.

Neurophysiological correlates of delinquent behaviour in adult subjects with ADHD

The attention deficit/hyperactivity disorder (ADHD) shows an increased prevalence in arrested offenders compared to the normal population. The aim of the present study was to investigate whether ADHD symptoms are a major risk factor for criminal behaviour, or whether further deficits, mainly abnormalities in emotion-processing, have to be considered as important additional factors that promote delinquency in the presence of ADHD symptomatology. Event related potentials (ERPs) of 13 non-delinquent and 13 delinquent subjects with ADHD and 13 controls were compared using a modified visual Go/Nogo continuous performance task (VCPT) and a newly developed version of the visual CPT that additionally requires emotional evaluation (ECPT). ERPs were analyzed regarding their topographies and Global Field Power (GFP). Offenders with ADHD differed from non-delinquent subjects with ADHD in the ERPs representing higher-order visual processing of objects and faces (N170) and facial affect (P200), and in late monitoring and evaluative functions (LPC) of behavioural response inhibition. Concerning neural activity thought to reflect the allocation of neural resources and cognitive processing capability (P300 Go), response inhibition (P300 Nogo), and attention/expectancy (CNV), deviances were observable in both ADHD groups and may thus be attributed to ADHD rather than to delinquency. In conclusion, ADHD symptomatology may be a risk factor for delinquency, since some neural information processing deficits found in ADHD seemed to be even more pronounced in offenders with ADHD. However, our results suggest additional risk factors consisting of deviant higher-order visual processing, especially of facial affect, as well as abnormalities in monitoring and evaluative functions of response inhibition.

Different brain activities predict retrieval success during emotional and semantic encoding

There is an increasing line of evidence supporting the idea that the formation of lasting memories involves neural activity preceding stimulus presentation. Following this line, we presented words in an incidental learning setting and manipulated the prestimulus state by asking the participants to perform either an emotional (neutral or emotional) or a semantic (animate or inanimate) decision task. Later, we tested the retrieval of each previously presented word with a recognition memory test. For both conditions, the subsequent memory effect (SME) was defined as ERP difference between subsequently remembered and forgotten words. Comparing the prestimulus SME between and within the two conditions yielded topographic differences in the time interval from -1300 to -700 msec before stimulus onset. This indicates that the activity of brain areas involved in incidental encoding of semantic information varied in the spatial distribution of ERPs, depending on the emotional and semantic requirements of the task. These findings provide evidence that there is a difference in semantic and emotional preparatory processes, which modulates successful encoding into episodic memory. This difference suggests that there are multiple task-specific functional neural systems that support memory formation. These systems differ in location and/or relative contribution of some of the brain structures that generate the measured scalp electric fields. Consequently, the cognitive processes that enable memory formation depend on the differential semantic nature of the study task and reflect differences in the preparatory processing of the multiple semantic components of a word's meaning.

Empathy matters: ERP evidence for inter-individual differences in social language processing

When an adult claims he cannot sleep without his teddy bear, people tend to react surprised. Language interpretation is, thus, influenced by social context, such as who the speaker is. The present study reveals inter-individual differences in brain reactivity to social aspects of language. Whereas women showed brain reactivity when stereotype-based inferences about a speaker conflicted with the content of the message, men did not. This sex difference in social information processing can be explained by a specific cognitive trait, one's ability to empathize. Individuals who empathize to a greater degree revealed larger N400 effects (as well as a larger increase in γ-band power) to socially relevant information. These results indicate that individuals with high-empathizing skills are able to rapidly integrate information about the speaker with the content of the message, as they make use of voice-based inferences about the speaker to process language in a top-down manner. Alternatively, individuals with lower empathizing skills did not use information about social stereotypes in implicit sentence comprehension, but rather took a more bottom-up approach to the processing of these social pragmatic sentences.

Spatiotemporal mapping of sex differences during attentional processing

Functional neuroimaging studies have increasingly aimed at approximating neural substrates of human cognitive sex differences elicited by visuospatial challenge. It has been suggested that females and males use different behaviorally relevant neurocognitive strategies. In females, greater right prefrontal cortex activation has been found in several studies. The spatiotemporal dynamics of neural events associated with these sex differences is still unclear. We studied 22 female and 22 male participants matched for age, education, and nicotine with 29-channel-electroencephalogram recorded under a visual selective attention paradigm, the Attention Network Test. Visual event-related potentials (ERP) were topographically analyzed and neuroelectric sources were estimated. In absence of behavioral differences, ERP analysis revealed a novel frontal-occipital second peak of visual N100 that was significantly increased in females relative to males. Further, in females exclusively, a corresponding central ERP component at around 220 ms was found; here, a strong correlation between stimulus salience and sex difference of the central ERP component amplitude was observed. Subsequent source analysis revealed increased cortical current densities in right rostral prefrontal (BA 10) and occipital cortex (BA 19) in female subjects. This is the first study to report on a tripartite association between sex differences in ERPs, visual stimulus salience, and right prefrontal cortex activation during attentional processing.

Gender related differences in visual and auditory processing of verbal and figural tasks

The aim of the present study was to investigate gender related differences in brain activity for tasks of verbal and figural content presented in the visual and auditory modality. Thirty male and 30 female respondents solved four tasks while their electroencephalogram (EEG) was recorded. Also recorded was the percentage of oxygen saturation of hemoglobin (%StO(2)) in the respondents' frontal brain areas with near-infrared spectroscopy (NIRS). The main findings of the study can be summarized as follows. (1) Most pronounced differences between males and females were observed for the factor modality-visual/auditory. (2) Gender related differences in neuroelectric brain responses could be observed during the solution of auditory and visual tasks; however, on the behavioral level only for the visual tasks did females display shorter reaction times than males. The ERP amplitudes of the early evoked gamma response, P1, and P3 were higher in females than males, whereas the N4 amplitude was higher in males than females. The differences were more noticeable in the visual modality. The NIRS showed a more bilateral involvement of the frontal brain areas in females as compared with a more left hemispheric frontal activity in males. In the task conditions an increase in right hemispheric activity in females was observed; however, this increase was less pronounced in the visual than the auditory domain, indicating a more lateralized processing of visual stimuli in females. Taken all together the results suggest that the females' visual event-categorization process is more efficient than in males.

The interactive effect of the cholinergic system and acute ovarian suppression on the brain: an fMRI study

Recent evidence suggests that loss of ovarian function following ovariectomy is a risk factor for Alzheimer's disease (AD); however, the biological basis of this risk remains poorly understood. We carried out an fMRI study into the interaction between loss of ovarian function (after Gonadotropin Hormone Releasing Hormone agonist (GnRHa) treatment) and scopolamine (a cholinergic antagonist used to model the memory decline associated with aging and AD). Behaviorally, cholinergic depletion produced a deficit in verbal recognition performance in both GnRHa-treated women and wait list controls, but only GnRHa-treated women made more false positive errors with cholinergic depletion. Similarly, cholinergic depletion produced a decrease in activation in the left inferior frontal gyrus (LIFG; Brodmann area 45)--a brain region implicated in retrieving word meaning--in both groups, and activation in this area was further reduced following GnRHa treatment. These findings suggest biological mechanisms through which ovarian hormone suppression may interact with the cholinergic system and the LIFG. Furthermore, this interaction may provide a useful model to help explain reports of increased risk for cognitive decline and AD in women following ovariectomy.

Lack of generalizability of sex differences in the fMRI BOLD activity associated with language processing in adults

A lack of consensus exists as to whether there are sex differences in the fMRI BOLD signal correlates of language processing in the human brain. Here, whole-brain fMRI was used to examine the neural activity of 46 adults performing one of two sets of language tasks. Conservative quantitative and qualitative criteria identified a handful of statistically significant regions of "sex difference" within each task separately. When each of the two sets of regions was investigated in the group of subjects performing the other task set, however, most of the identified "sex differences" failed to generalize. Identical analyses of the same subjects divided into sex-matched pseudorandom control groups for each task set separately revealed that it is possible to observe a similar number of statistically significant regions of "group difference" in the task-associated BOLD signal, even when the groups do not differ on any of the measured behavioral parameters, or any obvious demographic characteristic. Together, these results suggest that one should be cautious when interpreting studies that purport to have identified regions of difference between groups, whether those groups are divided by sex or by any other criterion. In particular, generalization or replication of a result in independent data sets is necessary for establishing conclusive support for any hypothesis about differences in brain function between groups.

Delayed auditory feedback effects during reading and conversation tasks: gender differences in fluent adults

Delayed auditory feedback (DAF) impacts the speech fluency of normally fluent males more than that of normally fluent females. Understanding this gender difference may contribute to our understanding of gender differences in the prevalence of developmental stuttering. To characterize this gender difference in fluent people, DAF-induced dysfluency was measured in 20 male and 21 female young adults during oral reading and conversation tasks. Stutter-like dysfluencies (SLDs), articulation errors, interjections, reading errors, and speech rate were measured for both speech tasks as the participant spoke without feedback, with non-delayed feedback, and with DAF presented with 5 delay intervals (14 conditions total). DAF induced SLDs (but not other dysfluencies) more frequently during conversation than reading, and this effect was significantly greater for males than females (Gender x Task x Feedback interaction). Males also produced significantly more reading errors than females. DAF reduced speaking rate significantly more while reading than conversing (Task x Feedback interaction). DAF significantly decreased the frequency of interjections and increased the frequency of articulation errors; however, no Gender effects on these variables were observed. Although significant order effects indicated improved fluency across trials, covariance analysis suggested that order effects could not explain other results.

EDUCATIONAL OBJECTIVES

After reading this article, the reader will be able to (1) Discuss developmental stuttering (DS) and gender differences in DS prevalence. (2) Define delayed auditory feedback (DAF). (3) Evaluate the evidence that gender is linked to DAF effects on fluent people. (4) Summarize the results of new research designed to assess sex differences in DAF effects on speech fluency in normally fluent adults. (5) Evaluate the degree to which evidence from the literature indicating that individual differences in attentional control may help us understand gender difference in DAF effects and possibly in DS prevalence as well.

The functional anatomy of semantic retrieval is influenced by gender, menstrual cycle, and sex hormones

This study examines the neurobiology of semantic retrieval and describes the influence of gender, menstrual cycle, and sex hormones on semantic networks. Healthy right-handed subjects (12 men, 12 women) were investigated with 3T-fMRI during synonym generation. Behavioral performance and sex hormone levels were assessed. Women were examined during the early follicular and midluteal cycle phase. The activation pattern in all groups involved left frontal and temporal as well as bilateral medial frontal, cingulate, occipital, basal ganglia, and cerebellar regions. Men showed greater left frontal activation than women in both menstrual cycle phases. Women yielded high correlations of left prefrontal activation with estradiol in the midluteal phase and with progesterone in both phases. Testosterone levels correlated highly with left prefrontal activation in all three groups. In all, we describe a cerebral network involved in semantic processing and demonstrate that it is significantly affected by gender and sex steroid hormones.