Effective connectivity hierarchically links temporoparietal and frontal areas of the auditory dorsal stream with the motor cortex lip area during speech perception

A left-hemispheric cortico-cortical network involving areas of the temporoparietal junction (Tpj) and the posterior inferior frontal gyrus (pIFG) is thought to support sensorimotor integration of speech perception into articulatory motor activation, but how this network links with the lip area of the primary motor cortex (M1) during speech perception is unclear. Using paired-coil focal transcranial magnetic stimulation (TMS) in healthy subjects, we demonstrate that Tpj → M1 and pIFG → M1 effective connectivity increased when listening to speech compared to white noise. A virtual lesion induced by continuous theta-burst TMS (cTBS) of the pIFG abolished the task-dependent increase in pIFG → M1 but not Tpj → M1 effective connectivity during speech perception, whereas cTBS of Tpj abolished the task-dependent increase of both effective connectivities. We conclude that speech perception enhances effective connectivity between areas of the auditory dorsal stream and M1. Tpj is situated at a hierarchically high level, integrating speech perception into motor activation through the pIFG.     

经颅直流电刺激对健康人群反应抑制的影响

反应抑制是指抑制不恰当的或不符合当前需要的行为的能力, 研究表明反应抑制主要与额下回、背外侧前额叶和前辅助运动区的功能有关。经颅直流电刺激(tDCS)是一种非侵入式脑刺激技术, 近年来对健康人群使用tDCS刺激相应脑区从而影响反应抑制功能的研究日益增多, 但主要研究结果不一致。阐明tDCS影响反应抑制具体的神经机制、减少tDCS研究的异质性、探索更有效的tDCS刺激方式和确定tDCS效果的年龄依赖性差异已成为目前亟待解决的问题。     

Monitor yourself! Deficient error-related brain activity predicts real-life self-control failures

Despite their immense relevance, the neurocognitive mechanisms underlying real-life self-control failures (SCFs) are insufficiently understood. Whereas previous studies have shown that SCFs were associated with decreased activity in the right inferior frontal gyrus (rIFG; a region involved in cognitive control), here we consider the possibility that the reduced implementation of cognitive control in individuals with low self-control may be due to impaired performance monitoring. Following a brain-as-predictor approach, we combined experience sampling of daily SCFs with functional magnetic resonance imaging (fMRI) in a Stroop task. In our sample of 118 participants, proneness to SCF was reliably predicted by low error-related activation of a performance-monitoring network (comprising anterior mid-cingulate cortex, presupplementary motor area, and anterior insula), low posterror rIFG activation, and reduced posterror slowing. Remarkably, these neural and behavioral measures predicted variability in SCFs beyond what was predicted by self-reported trait self-control. These results suggest that real-life SCFs may result from deficient performance monitoring, leading to reduced recruitment of cognitive control after responses that conflict with superordinate goals.     

外显和内隐情绪韵律加工的脑机制：近红外成像研究

准确识别言语中的情绪韵律信息对社会交往非常重要。本研究采用功能近红外成像技术, 探索外显和内隐情绪加工条件下愤怒、恐惧、快乐三种情绪韵律加工过程中的大脑皮层神经活动。结果表明, 对愤怒、恐惧、快乐韵律进行特异性加工的脑区分别为左侧额极/眶额叶、右侧缘上回、左侧额下回, 其中右侧缘上回脑区同时受到情绪和任务的调控。此外, 右侧颞中回、颞下回和颞极在情绪外显任务中的激活明显强于内隐任务。本研究的结果部分支持了情绪韵律的层次模型, 也对该模型的第三层次, 即“额区对语音情绪信息的精细加工需要外显性情绪加工任务参与”提出了质疑。     

Auditory language comprehension: an event-related fMRI study on the processing of syntactic and lexical information

The functional specificity of different brain areas recruited in auditory language processing was investigated by means of event-related functional magnetic resonance imaging (fMRI) while subjects listened to speech input varying in the presence or absence of semantic and syntactic information. There were two sentence conditions containing syntactic structure, i.e., normal speech (consisting of function and content words), syntactic speech (consisting of function words and pseudowords), and two word-list conditions, i.e., real words and pseudowords. The processing of auditory language, in general, correlates with significant activation in the primary auditory cortices and in adjacent compartments of the superior temporal gyrus bilaterally. Processing of normal speech appeared to have a special status, as no frontal activation was observed in this case but was seen in the three other conditions. This difference may point toward a certain automaticity of the linguistic processes used during normal speech comprehension. When considering the three other conditions, we found that these were correlated with activation in both left and right frontal cortices. An increase of activation in the planum polare bilaterally and in the deep portion of the left frontal operculum was found exclusively when syntactic processes were in focus. Thus, the present data may be taken to suggest an involvement of the left frontal and bilateral temporal cortex when processing syntactic information during comprehension.     

Auditory language comprehension: an event-related fMRI study on the processing of syntactic and lexical information

The functional specificity of different brain regions recruited in auditory language processing was investigated by means of event-related functional magnetic resonance imaging (fMRI) while subjects listened to speech input varying in the presence or absence of semantic and syntactic information. There were two sentence conditions containing syntactic structure, i.e., normal speech (consisting of function and content words), syntactic speech (consisting of function words and pseudowords), and two word-list conditions, i.e., real words and pseudowords. The processing of auditory language, in general, correlates with significant activation in the primary auditory cortices and in adjacent compartments of the superior temporal gyrus bilaterally. Processing of normal speech appeared to have a special status, as no frontal activation was observed in this case but was seen in the other three conditions. This difference may point toward a certain automaticity of the linguistic processes used during normal speech comprehension. When considering the three other conditions, we found that these were correlated with activation in both left and right frontal cortices. An increase of activation in the planum polare bilaterally and in the deep portion of the left frontal operculum was found exclusively when syntactic processes were in focus. Thus, the present data may be taken to suggest an involvement of the left frontal and bilateral temporal cortex when processing syntactic information during comprehension.     

Effects of cognitive load on neural and behavioral responses to smoking-cue distractors

Smoking cessation failures are frequently thought to reflect poor top-down regulatory control over behavior. Previous studies have suggested that smoking cues occupy limited working memory resources, an effect that may contribute to difficulty achieving abstinence. Few studies have evaluated the effects of cognitive load on the ability to actively maintain information in the face of distracting smoking cues. For the present study, we adapted an fMRI probed recall task under low and high cognitive load with three distractor conditions: control, neutral images, or smoking-related images. Consistent with a limited-resource model of cue reactivity, we predicted that the performance of daily smokers (n = 17) would be most impaired when high load was paired with smoking distractors. The results demonstrated a main effect of load, with decreased accuracy under high, as compared to low, cognitive load. Surprisingly, an interaction revealed that the effect of load was weakest in the smoking cue distractor condition. Along with this behavioral effect, we observed significantly greater activation of the right inferior frontal gyrus (rIFG) in the low-load condition than in the high-load condition for trials containing smoking cue distractors. Furthermore, load-related changes in rIFG activation partially mediated the effects of load on task accuracy in the smoking-cue distractor condition. These findings are discussed in the context of prevailing cognitive and cue reactivity theories. These results suggest that high cognitive load does not necessarily make smokers more susceptible to interference from smoking-related stimuli, and that elevated load may even have a buffering effect in the presence of smoking cues under certain conditions.     

The nature and treatment of stuttering as revealed by fMRI A within- and between-group comparison

This article reviews some of our recent functional magnetic resonance imaging (fMRI) studies of stuttering. Using event-related fMRI experiments, we investigated brain activation during speech production. Results of three studies comparing persons who stutter (PWS) and persons who do not stutter (PWNS) are outlined. Their findings point to a region in the right frontal operculum (RFO) that was consistently implicated in stuttering. During overt reading and before fluency shaping therapy, PWS showed higher and more distributed neuronal activation than PWNS. Immediately after therapy differential activations were even more distributed and left sided. They extended to frontal, temporal, and parietal regions, anterior cingulate, insula, and putamen. These over-activations were slightly reduced and again more right sided two years after therapy. Left frontal deactivations remained stable over two years of observation, and therefore possibly indicate a dysfunction. After therapy, we noted higher activations in persons who stutter moderately than in those who stutter severely. These activations might reflect patterns of compensation. We discuss why these findings suggest that fluency-inducing techniques might synchronize a disturbed signal transmission between auditory, speech motor planning, and motor areas.

Educational objectives: The reader will learn about and be able to: (1) identify regions of brain activations and deactivations specific for PWS; (2) describe brain activation changes induced by fluency shaping therapy; and (3) discuss the correlation between stuttering severity and brain activation.     

The effect of an intensive behavioral program on the distribution of EEG alpha power in stutterers during the processing of verbal and visuospatial information

Prior to an intensive behavioral treatment program, stutterers showed greater than normal activation of the posterior frontal region of the right hemisphere during the performance of speech tasks. After treatment they showed increases in proportional alpha for most regions of the two cerebral hemispheres, but most markedly for the posterior frontal region of the right hemisphere for both verbal and nonverbal tasks. This increase resulted in a reversal of the previous R/L interhemispheric alpha relationships with the left posterior frontal region showing greater activation during speech after treatment. The relationship of this finding to previous findings is briefly discussed and an hypothesis of decreased inhibitory control of the right hemisphere at the posterior frontal region by the left hemisphere during speech in stutterers is proposed and briefly expounded.     

Neural basis responsible for self-control association with procrastination: Right MFC and bilateral OFC functional connectivity with left dlPFC

Converging theory and evidence highlights procrastination as a form of self-control failure. However, the underlying neural correlates of how self-control is associated with procrastination remains unclear. As such we investigated the neural basis for self-control association with procrastination using voxel-based morphometry (VBM) and resting-state functional connectivity (FC) approaches. The VBM results showed a positive correlation between self-control and the gray matter volume of left dorsolateral prefrontal cortex (dlPFC). Then the FC of left dlPFC to lateral orbital frontal cortex (lOFC) and right dorsal medial frontal cortex (dMFC) were all negatively correlated to procrastination and showed a mediating effect. This indicates that brain functional communication involves in emotion regulation and valuation processing may account for the association between self-control and procrastination.     

Assessing changes in brain electrical activity and functional connectivity while overtaking a vehicle

ABSTRACT

Driving is a daily requirement and an indispensable activity for many people. However, still little is known about how driving is supported by the brain. We used electroencephalography to study the changes in brain activity and its functional connectivity in a simulated driving task. We focused on overtaking and studied this activity in three phases: before overtake, during overtake, and after overtake. Our results showed that mu power in motor and sensorimotor areas decreased during overtake and again increased after overtake. On the other hand, beta oscillations in frontal areas were at their highest level in the “before overtake” phase. It can be interpreted that the “before overtake” was the most attention-demanding phase. In addition, we found that the connectivity between right and left prefrontal regions and right and left occipital regions in alpha (and mu) band power was significantly stronger in the “during overtake” compared to the other two conditions.     

Brain activity varies with modulation of dynamic pitch variance in sentence melody

Fourteen native speakers of German heard normal sentences, sentences which were either lacking dynamic pitch variation (flattened speech), or comprised of intonation contour exclusively (degraded speech). Participants were to listen carefully to the sentences and to perform a rehearsal task. Passive listening to flattened speech compared to normal speech produced strong brain responses in right cortical areas, particularly in the posterior superior temporal gyrus (pSTG). Passive listening to degraded speech compared to either normal or flattened speech particularly involved fronto-opercular and subcortical (Putamen, Caudate Nucleus) regions bilaterally. Additionally the Rolandic operculum (premotor cortex) in the right hemisphere subserved processing of neat sentence intonation. As a function of explicit rehearsing sentence intonation we found several activation foci in the left inferior frontal gyrus (Broca's area), the left inferior precentral sulcus, and the left Rolandic fissure. The data allow several suggestions: First, both flattened and degraded speech evoked differential brain responses in the pSTG, particularly in the planum temporale (PT) bilaterally indicating that this region mediates integration of slowly and rapidly changing acoustic cues during comprehension of spoken language. Second, the bilateral circuit active whilst participants receive degraded speech reflects general effort allocation. Third, the differential finding for passive perception and explicit rehearsal of intonation contour suggests a right fronto-lateral network for processing and a left fronto-lateral network for producing prosodic information. Finally, it appears that brain areas which subserve speech (frontal operculum) and premotor functions (Rolandic operculum) coincidently support the processing of intonation contour in spoken sentence comprehension.     

错误信息持续影响效应的神经基础

本研究通过分析任务态fMRI下相关脑区激活及功能连接的条件间差异以揭示CIEM神经基础并为心理模型更新及记忆提取失败假说提供更多证据。结果发现, 更正条件的推理分显著高于控制条件, 存在CIEM。编码阶段左颞中回在更正条件下的激活显著弱于控制条件, 提取阶段更正条件下额中回及前扣带回激活更弱、额中回与中央前回的功能连接更强。结果提示上述脑区可能参与了CIEM的形成, 并从神经层面提供了心理模型更新和记忆提取失败假说可能解释了CIEM形成的不同阶段的证据。     

Extraversion modulates functional connectivity hubs of resting‐state brain networks

Personality dimension extraversion describes individual differences in social behaviour and socio‐emotional functioning. The intrinsic functional connectivity patterns of the brain are reportedly associated with extraversion. However, whether or not extraversion is associated with functional hubs warrants clarification. Functional hubs are involved in the rapid integration of neural processing, and their dysfunction contributes to the development of neuropsychiatric disorders. In this study, we employed the functional connectivity density (FCD) method for the first time to distinguish the energy‐efficient hubs associated with extraversion. The resting‐state functional magnetic resonance imaging data of 71 healthy subjects were used in the analysis. Short‐range FCD was positively correlated with extraversion in the left cuneus, revealing a link between the local functional activity of this region and extraversion in risk‐taking. Long‐range FCD was negatively correlated with extraversion in the right superior frontal gyrus and the inferior frontal gyrus. Seed‐based resting‐state functional connectivity (RSFC) analyses revealed that a decreased long‐range FCD in individuals with high extraversion scores showed a low long‐range functional connectivity pattern between the medial and dorsolateral prefrontal cortex, middle temporal gyrus, and anterior cingulate cortex. This result suggests that decreased RSFC patterns are responsible for self‐esteem, self‐evaluation, and inhibitory behaviour system that account for the modulation and shaping of extraversion. Overall, our results emphasize specific brain hubs, and reveal long‐range functional connections in relation to extraversion, thereby providing a neurobiological basis of extraversion.     

The effects of simulated stuttering and prolonged speech on the neural activation patterns of stuttering and nonstuttering adults

Functional magnetic resonance imaging was used to investigate the neural correlates of passive listening, habitual speech and two modified speech patterns (simulated stuttering and prolonged speech) in stuttering and nonstuttering adults. Within-group comparisons revealed increased right hemisphere biased activation of speech-related regions during the simulated stuttered and prolonged speech tasks, relative to the habitual speech task, in the stuttering group. No significant activation differences were observed within the nonstuttering participants during these speech conditions. Between-group comparisons revealed less left superior temporal gyrus activation in stutterers during habitual speech and increased right inferior frontal gyrus activation during simulated stuttering relative to nonstutterers. Stutterers were also found to have increased activation in the left middle and superior temporal gyri and right insula, primary motor cortex and supplementary motor cortex during the passive listening condition relative to nonstutterers. The results provide further evidence for the presence of functional deficiencies underlying auditory processing, motor planning and execution in people who stutter, with these differences being affected by speech manner.     

藏汉双语者汉语阅读理解的静息态功能连接分析

研究结合静息态全脑功能连接密度和基于种子点的功能连接（FC）分析考察了藏汉双语者汉语（L2）阅读各子能力（细节捕捉和推理判断）的固有脑功能组织特点。结果发现左侧额下回—左侧颞上回和右侧舌回—右侧中央前回之间的FC值均与细节捕捉题得分和推理判断题得分呈显著正相关,但是左侧额下回—右侧顶下小叶之间的FC值只与推理判断题得分呈显著正相关。表明藏汉双语者汉语阅读各子能力之间既有重叠的又有不同的功能连接通路。     

The effect of bicephalic stimulation of the dorsolateral prefrontal cortex on the attentional bias for threat: A transcranial direct current stimulation study

Previous stimulation studies demonstrated that the dorsolateral prefrontal cortex (DLPFC) is involved in threat processing. According to a model of emotional processing, an unbalance between the two DLPFCs, with a hyperactivation of right frontal areas, is involved in the processing of negative emotions and genesis of anxiety. In the present study, we investigated the role of the right and left DLPFC in threat processing in healthy women who also completed the State-Trait Anxiety Inventory (STAI). We simultaneously modulated the activity of the right and left dorsolateral prefrontal cortex by applying bicephalic transcranial direct current stimulation (tDCS) before participants completed a modified version of the classic Posner task using threatening and nonthreatening stimuli as spatial cues. Anodal stimulation on the right DLPFC with a simultaneous cathodal stimulation over the left side induced a disengagement bias in individuals with low STAI scores and a facilitation bias in individuals with high STAI scores. Anodal stimulation on the left DLPFC with the simultaneous cathodal stimulation over the right side did not affect threat processing. The findings of the present study provided specific support to the hypothesis that unbalanced activation between left and right hemispheres with enhanced activation of the right DLPFC is critical in early top-down threat processing in healthy individuals.     

言语中的音高信息声学语音学加工的大脑偏侧化

旨在探讨言语中音高信息自下而上的声学语音学加工的神经机制和大脑偏侧化.发现,被动听和主动判断任务分别激活了颞叶和额叶,激活在颞极、颞上回和额下回眶部表现出明显的右侧优势.结果表明,对言语中音高信息自下而上的声学语音学加工主要是右脑的功能,言语与非言语信号的音高信息可能有相似的加工机制,支持Gandour等提出的理论.     

Trait lasting alteration of the brain default mode network in experienced meditators and the experiential selfhood

Based on the finding in novices that four months of meditation training significantly increases frontal default mode network (DMN) module/subnet synchrony while decreasing left and right posterior DMN modules synchrony, the current study tested the prediction whether experienced meditators (those who are practising meditation intensively for several years) had a change in the DMN “trinity” of modules as a baseline trait characteristic and whether this change is in a similar direction as in the novice trainees who practised meditation for only four months. Comparison of functional connectivity within DMN subnets (measured by electroencephalogram operational synchrony in the three separate DMN modules) between five experienced meditators and 10 naïve participants (who were about to start the meditation training) fully support the prediction. Interpretation that links such DMN subnets changes to the three-dimensional components of the experiential selfhood was proposed.     

On the lateralization of emotional prosody: an event-related functional MR investigation

In order to investigate the lateralization of emotional speech we recorded the brain responses to three emotional intonations in two conditions, i.e., "normal" speech and "prosodic" speech (i.e., speech with no linguistic meaning, but retaining the 'slow prosodic modulations' of speech). Participants listened to semantically neutral sentences spoken with a positive, neutral, or negative intonation in both conditions and judged how positive, negative, or neutral the intonation was on a five-point scale. Core peri-sylvian language areas, as well as some frontal and subcortical areas were activated bilaterally in the normal speech condition. In contrast, a bilateral fronto-opercular region was active when participants listened to prosodic speech. Positive and negative intonations elicited a bilateral fronto-temporal and subcortical pattern in the normal speech condition, and more frontal activation in the prosodic speech condition. The current results call into question an exclusive right hemisphere lateralization of emotional prosody and expand patient data on the functional role of the basal ganglia during the perception of emotional prosody.