Cortex

Affective prosody facilitates the communication of emotions by modulating paralinguistic features of speech (e.g., pitch and rhythm). Patients with brain injuries may exhibit impaired expression of affective prosody, referred to as expressive aprosodia, adversely impacting social interactions and quality of life. Despite many previous lesion studies, relatively few studies have investigated neural correlates of expressive aprosodia using a combination of lesion location, as well as associated structural and functional network mapping, within a large patient sample. There is especially a need to advance our understanding of the neurobiology associated with expressive aprosodia in the chronic phase (i.e., > 3 months after lesion onset) given the practical importance of long-term outcomes in regard to social functioning and quality of life. The present study therefore aimed to characterize how expressive aprosodia relates to lesion location and disruption of associated structural and functional brain networks in a large sample of participants with chronic focal brain lesions (N = 673). Using a clinical expert evaluation of prosody and multi-modal lesion mapping, the results showed that expressive aprosodia was most strongly associated with i) lesions affecting right-lateralized fronto-insular-striatal regions, ii) prominent disconnection of right-lateralized cortico-subcortical pathways, and iii) damage to regions exhibiting functional connectivity with subcortical (basal ganglia, thalamus) and cortical ventral attention/salience networks. Overall, these findings are consistent with a previously proposed dorsal stream for expressive aprosodia and provide further insights into the neural architecture whose damage is associated with chronic expressive aprosodia.

Anosognosia, a lack of awareness of a neurological deficit, is a multi-component disorder involving coexisting neurological and cognitive impairments. Patients with anosognosia for hemiparesis fail to use new information about their bodily self to update beliefs. Overconfidence in situations of uncertainty and a failure to adjust beliefs in a verbal riddle task have been identified in a previous case series. This prospective study extends these findings using the same verbal riddle task and an additional non-verbal picture riddle task in 41 stroke patients and 22 age-matched controls. Each riddle contains five clues leading to a target word or picture. After each clue, participants provide a guess and a confidence rating. All riddles are designed to create an initial situation of uncertainty. The picture riddle is simpler and less dependent on language and memory capacities. In our cohort, 14 out of 41 patients were unaware of their paresis. Contrary to prior work, we found the riddle paradigm to be unsuitable for measuring belief-updating. Regarding overconfidence, the level of confidence for the first two clues differed significantly between patients with anosognosia and controls, but not between patients with and without deficit awareness in the word riddle. In the picture riddle, patients with anosognosia had significantly higher confidence levels than the other subgroups. To conclude, overconfidence was most common in patients with anosognosia but was not exclusive to them.

Goal-directed grasping actions are often planned with respect to their intended final states, as reflected in the end-state comfort effect (ESC) where individuals adopt initially uncomfortable grasp postures to ensure a comfortable final posture. The present study investigates the neurophysiological mechanisms underlying the processing of action sequences in grasping using event-related potentials (ERPs) within a priming paradigm. Participants were presented with prime images showing initial grasp postures (overhand or underhand grip) followed by target images representing final grasp postures (thumb-up or thumb-down) that together depicted either possible or impossible action sequences. Participants responded to the color of the upper part of the bar in the target image, while grasp postures were task-irrelevant. The results reveal that responses to target images representing an uncomfortable final grasp (thumb-down) following an underhand grip in the prime were slower and elicited a stronger P300 amplitude compared to responses to comfortable final grasp targets (thumb-up). This effect was observed only when the prime-target sequence represented a physically possible action. These results suggest that perceiving an initial underhand grip leads to the anticipation of a functional final action state. Deviations from this expected outcome result in greater cognitive processing effort, as reflected by increased P300 amplitudes. This suggests that action representations in grasping are anticipatory in nature and incorporate information about likely future action outcomes. The findings are consistent with ideo-motor theories, highlighting the role of anticipated action effects in action processing, and provide novel insights into the cognitive and neural underpinnings of action representation.

Accurately determining prevalence of post-stroke cognitive impairment (PSCI) is essential for research, yet methodological choices vary extensively across studies. This study theoretically and statistically compared four statistical approaches to PSCI classification using a cognitive screen in 1,951 stroke patients and 407 healthy controls. We contrasted (1) the common "at least one positive test" method using 5th centile cut-offs per subtest (uncorrected), (2) a Bonferroni-adjusted variant controlling for multiple comparisons, (3) a total-score summing subtest scores, and (4) a non-parametric Multivariate Normative Comparison (MNC) approach. False-positive rates (i.e., classifying healthy controls as impaired) (FPRs), PSCI prevalence and discrimination of stroke patients and healthy controls were contrasted between methods. PSCI identification using uncorrected 5th centile cut-offs per test resulted in impairment identification in 22% of healthy controls (99% CI [18-27]), while Bonferroni, total-score, and MNC methods maintained a rate of 5% identification of impairment. Corresponding PSCI prevalence estimates in stroke patients were 82%, 63%, 38%, and 55%, respectively. Contrary to predictions, the Bonferroni-adjusted method produced the greatest discrimination between stroke and control groups while ensuring family-wise error control. These findings demonstrate that uncorrected screening criteria can substantially inflate PSCI classifications in healthy controls even for ceiling-bounded screening tests, and that simple correction methods can achieve robust statistical control without loss of interpretability. Bonferroni-adjusted centile cut-offs are recommended for research studies in which PSCI is identified across multiple tests, as they maximize diagnostic specificity and maintain conceptual transparency compared to more complex multivariate approaches.

Competing neurocognitive models offer different accounts of how the sense of agency (the experience of controlling one's actions) and the sense of ownership (the experience that one's body belongs to oneself) relate within bodily self-awareness. The additive model proposes that agency entails ownership, the independence model treats the two experiences as functionally distinct, and the interactive model suggests reciprocal influences between them. However, empirical tests comparing these predictions within a single coherent experimental paradigm remain limited. Here, we developed an immersive virtual reality paradigm to orthogonally manipulate agency- and ownership-related cues within a goal-directed action task. Fifty-six participants pressed a (virtual) button to switch on a lightbulb. Agency was manipulated by comparing voluntary self-generated and externally induced passive movements and action-outcome delays, whereas ownership was manipulated through the anatomical plausibility of the avatar's hands. Direct and indirect agency and ownership indices were collected. Direct explicit judgements revealed both domain-specific and reciprocal influences: agency was modulated by action-related cues and by anatomical plausibility, whereas ownership was modulated by anatomical plausibility and by action-related cues, consistent with an interactive account. Indirect measures showed a distinct pattern: intentional binding was influenced by action-outcome contingency and was not affected by ownership manipulations, whereas proprioceptive drift varied as a function of anatomical plausibility. We propose a hierarchical two-stage account that integrates previous cognitive models across distinct processing levels, in which agency and ownership arise from partly independent sensorimotor processes at an implicit level but dynamically interact at the level of metacognitive, explicit self-attribution.

Schizophrenia and related psychoses are characterized by reductions in hippocampal volume and morphometric hippocampal-cortical covariance. No study to date has inferred the temporal relationship between deviations in subfield and adjacent white matter volume and connectivity across psychosis. To explore this relationship, we sampled cross-sectional neuroimaging data from 174 patients and 120 non-clinical controls from two studies on first- and multi-episode psychosis. We applied Subtype and Stage Inference (SuStaIn), a machine learning algorithm combining clustering and disease progression modeling, to eight measures of hippocampal volume and morphometric hippocampal-cortical covariance (subfields and white matter regions per hemisphere) combined. We then performed in-depth SuStaIn analyses for 18 volumes (five subfields and four white matter regions per hemisphere) and 18 connectivity measures (graph-theory-based participation coefficient) separately. Some patients and controls showed no deviations (no increase or decrease) from control means in volume and covariance. For individuals who did show deviations, we inferred data-driven stages from deviations in volume toward covariance. In-depth SuStaIn analyses inferred three distinct volume patterns (intact volume, subfield-dominant, whiter matter-dominant) followed by one of four possible connectivity patterns (intact connectivity, whiter matter-dominant, subfield-dominant, subiculum-dominant). These subtypes showed significant differences in age, patient-control ratio and associations between data-driven stages and memory. In previous work, altered hippocampal volume and morphometric covariance distinctively precede cognitive and clinical symptoms of psychosis. While not all patients were assigned a staging pattern for hippocampal volume or connectivity, our findings might thus contribute to elucidating distinct hippocampal patterns underlying heterogeneous manifestations of psychosis for a subgroup of patients.

Peripheral reaching to objects outside the direct line of sight supports motor flexibility. Deficits in this ability are the hallmark of optic ataxia, yet impairments may exist along a continuum and warrant investigation in larger, unselected samples. This study examined peripheral misreaching and its neuroanatomical correlates in stroke patients. Peripheral reaching was assessed using a standardized reach-to-grasp task in 86 ischemic stroke patients and 22 mean age-matched controls. Group-level analyses assessed effects of target location and reaching hand, and case-control comparisons quantified deficit prevalence. Lesion symptom mapping examined associations between lesion location and peripheral misreaching, and structural disconnection mapping assessed the impact of structural connectivity damage. At group level, stroke patients showed significantly greater peripheral misreaching than controls, with group differences emerging at older ages. Peripheral reaching deficits were present in 31 out of 86 stroke patients and were most pronounced in the contralesional field. Ipsilesional deficits were also observed, particularly after left hemisphere lesions. Lesion symptom mapping across 77 stroke patients with available MRI data associated left-field peripheral misreaching with the right supramarginal gyrus, while structural disconnection mapping implicated the right optic radiation. No lesion-behaviour associations were observed for right-field peripheral misreaching, though right hemisphere lesion volume correlated with misreaching in this condition. These findings indicate that peripheral reaching deficits after stroke are more common and heterogeneous than previously recognized. The involvement of the supramarginal gyrus suggests a broader role in visuomotor control, including attentional and proprioceptive processes. The right hemisphere dominance in lesion-behaviour associations raises questions about hemispheric specialization.

Arabic is spoken by more than 400 million people across a region experiencing a substantial increase in stroke burden. Yet, no comprehensively validated aphasia assessment battery exists that provides dialect-stratified norms across major Arabic-speaking communities. This critical narrative review evaluates Arabic aphasia assessment against explicit psychometric and linguistic criteria, identifying peer-reviewed instruments and synthesizing the methodological progress they represent, alongside two structural questions that are only partially resolved by existing instruments. The first is the diglossic register question: Modern Standard Arabic functions as a learned register whose distance from each speaker’s vernacular varies with education, and how this distance contributes to assessment score variance has not been quantified in within-subject clinical samples. The second is the nonconcatenative morphology question: Arabic root-and-pattern morphological operations, not specifically assessed by current aphasia batteries, leave possible morphology-specific vulnerability insufficiently tested. Recent dialect-specific instruments, including the Moroccan Arabic Bedside WAB-R, the Cairene Egyptian Arabic WAB-R, the Egyptian Arabic Comprehensive Aphasia Test, the Short Aphasia Test for Gulf Arabic, and the Arabic Discourse Assessment Tool, represent substantive progress and a necessary foundation. Building on it requires dialect-specific psycholinguistic databases, measurement-equivalence reporting as a publication standard, education- and literacy-stratified normative collection, and a within-subject crossover study quantifying the register-distance effect. Improving Arabic aphasia assessment is essential: lesion-symptom mapping in Arabic-speaking populations depends on instruments validated for the linguistic profile they assess.

Cognitive models propose that reading aloud relies on two routes, a lexical route for familiar word recognition and a sublexical route for graphene-to-phoneme conversion. Selective disruption of these routes results in surface or phonological dyslexia, respectively. Although the dual route model is well supported behaviorally, its white matter substrates remain incompletely characterized. This study examined the anatomical correlates of acquired lexical and sublexical reading impairments in patients with high-grade glioma in the dominant hemisphere. Thirty-seven patients underwent diffusion tensor imaging (DTI) and a comprehensive reading battery. Reading aloud of regular and irregular words, and pseudowords was used to classify patients as having intact reading, surface dyslexia or phonological dyslexia, based on normative criteria. Six language-related white matter tracts were reconstructed individually for each patient using subject-specific tractography. Each tract was then systematically segmented along its longitudinal axis, allowing diffusion parameters to be extracted from anatomically defined subsegments. Lesion-tract overlap measures were computed to quantify focal tract involvement. Fourteen patients exhibited impaired sublexical reading, 12 impaired lexical reading, and 11 intact reading. Deficits in the sublexical route were more frequent among patients with arcuate fasciculus lesion overlap, and sublexical error rates correlated with global tract integrity. Deficits in the lexical route were associated with the posterior temporal segment of the inferior longitudinal fasciculus, where surface dyslexia errors correlated with reduced fractional anisotropy. In contrast, uncinate fasciculus involvement was more frequent among patients with intact reading, indicating it does not contribute critically to either reading route. These findings provide a fine-grained structure-function mapping of the dual route reading model onto white matter pathways.

For decades, theorizing in the cognitive sciences was dominated by the assumption that abstract concepts, lacking directly perceivable referents, can only be represented and processed through amodal or verbal linguistic representations. More recently, refined hybrid grounded cognition theories have successfully been applied to account for abstract concepts within a multiple representation framework. According to this perspective, the meaning of abstract concepts is constituted by representations distributed across various experiential modal brain systems, including sensory, motor, emotional, mentalizing, and social interaction networks. Representations in these modal systems are complemented by representations in language-related and amodal hub regions, depending on the specific semantic content of the concept. In this article, we first outline a multiple representation framework within a hybrid grounded cognition approach and then review neuroscientific evidence concerning the neural substrate of abstract concepts related to sensory-motor features, mental states and social constellations. These findings indicate that modal sensory-motor, mentalizing, and social interaction brain systems contribute to the processing of particular types of abstract concepts, alongside representations in amodal semantic hub regions and language areas. Moreover, this body of research demonstrates that different modal neural circuits are engaged as a function of a concept's specific semantic content, thereby highlighting the heterogeneity of abstract concepts. Future research should address outstanding questions, including the precise functional contributions of distinct neural circuits to the representation of abstract concepts and the evaluation of predicted patterns of impairment in neurological and psychiatric patient populations.

Approximately 25% of patients with severe brain injuries who appear unresponsive on the bedside behavioral examination are covertly conscious-able to volitionally modulate their brain activity using task-based functional MRI or task-based EEG. Since the first description of covert consciousness in 2006, nearly all reports of covert consciousness have been in patients who were behaviorally awake, with their eyes open. These observations led to a widespread assumption that cortical activation associated with consciousness required a foundation of subcortical connections to produce wakefulness. We report the case of an 80-year-old woman with acute severe traumatic brain injury, whose level of consciousness was evaluated in the intensive care unit with a multimodal diagnostic protocol integrating behavioral, task-based fMRI, and task-based EEG assessments. Despite behavioral evidence of coma on every behavioral examination, the task-based fMRI and task-based EEG assessments both indicated the presence of covert consciousness. These observations suggest an unexpected phenomenon whereby awareness (i.e., volitional brain activity) can be dissociated from wakefulness (i.e., eye opening) in the human brain. The possibility that individuals who outwardly appear comatose may harbor covert consciousness carries both clinical and ethical weight, and unsettles long-held assumptions, embedded in the very term coma, that patients diagnosed as such are uniformly unaware and insensate.

Faces and voices are some of the most salient sources of information for identifying others' emotions. However, little research has focused on how emotional prosody modulates the earliest stages of face perception at the neural level. This study investigated priming effects of emotional prosody on the time course of subsequently presented emotional faces using event-related potentials (ERPs). Auditory prosodic primes (spoken sentences filtered to remove semantic information) expressing happy, neutral, or angry emotion were presented and immediately followed by a face expressing a congruent or incongruent emotion. After each trial, participants (n = 58) rated the face on valence and arousal. ERPs time-locked to face onset were analyzed at all time points and electrodes using data-driven mass univariate statistics. A significant main effect of face emotion was found spanning the N170, P2, and early EPN components. A significant main effect of voice emotion was found from approximately 50-100 msec and 150-400 msec, interpreted as increased attention in V1 and other non-face visual areas due to arousing vocal stimuli, especially angry ones. Critically, these factors did not interact, suggesting that face-voice congruency did not affect early perceptual face processing in this context. Behavioural results, however, showed that voice emotion influenced ratings of face valence and arousal, suggesting that voice prime and face information are integrated only at later cognitive but not early perceptual stages. Thus, prosody primes influenced visual processing before and after facial expressions were decoded, but face-voice congruency did not modulate early face emotion processing.

Rhythmic auditory exposure modulates subsequent speech processing, yet its effect on speech production remains poorly understood. People with Parkinson's disease (PD) or spinocerebellar ataxia (SCA) suffer from dysarthria, for which there is no treatment. Using a rhythmic priming approach, we investigated whether brief rhythmic primes modulate speech production and facilitate it in people with PD and SCA considered here as clinical models of basal ganglia dysfunction and cerebellar dysfunction, respectively. Fifty-eight native French speakers (20 controls, 24 people with PD, 14 people with SCA) read sentences following a regular prime, an irregular prime, or silence. We measured accuracy and the temporal features of speech production including speech initiation time, speech rate, and rhythmic metrics. Bayesian mixed-effects models were used for the statistical analyses of these outputs. Accuracy showed no effect of rhythmic priming. Regular primes consistently shortened speech initiation time in all populations, but the benefit of regular primes was smaller in people with PD than in controls. In People with SCA, speech rate decreased after regular primes. The impact of rhythmic priming on rhythmic metrics was limited. Together, these results indicate that perception-to-production rhythmic priming mainly affects global, rather than fine-grained, timing control of speech during speech production. They also shed light on the implications of the basal ganglia and cerebellum in the modulation of speech by rhythm. They also provide insights for speech production models, which currently lack an explicit mechanism for external rhythmic inputs. Clinically, they help inform rhythm-based speech and language therapy methods.

Processing a word's meaning activates some of its semantic neighbors that are related associatively or taxonomically. While prior studies have shown that both types of neighborhoods influence lexical processing, their underlying neural bases remain unclear, particularly regarding the involvement of the Anterior Temporal Lobe (ATL). This study used HD-tDCS to examine the role of the left lateral ATL in how associative and taxonomic semantic neighborhoods influence the lexico-semantic processing of abstract and concrete words. Participants (N = 42) performed a semantic concreteness judgment task on words, with and without left ATL stimulation, where neighborhood sizes were varied. A strong facilitative effect of concreteness was found in both real and sham conditions, consistent with the traditional concreteness effect. Both associative and taxonomic semantic neighborhoods influenced semantic judgments. Critically, ATL stimulation slowed responses to words with sparse neighborhoods, regardless of whether neighborhoods were defined associatively or taxonomically. Furthermore, the neighborhood effects were more readily apparent for abstract words, with significant interactions between stimulation and neighborhoods observed only in this subset. Together, the findings highlight the independent effects of associative and taxonomic neighborhoods in lexico-semantic processing and show that the ATL modulates the activation of both associative and taxonomic semantic neighborhoods, challenging models that characterize it solely as a taxonomic hub.

To characterize the distinct network principles underlying limb and oral apraxias, we investigated the structural brain lesions and white matter disconnections associated with limb apraxia (LA), buccofacial apraxia (BFA), and apraxia of speech (AOS) within a single cohort. In 136 patients with acute left-hemisphere ischemic stroke, LA was assessed using pantomime of tool use and communicative gestures, BFA via non-verbal orofacial movements, and AOS through perceptual evaluation of speech production tasks. We employed voxel-based, region-of-interest-based, and connectome-based lesion-symptom mapping to directly contrast the cortical damage and network disruptions associated with each deficit. LA was associated with damage to the inferior parietal lobule and widespread white matter disconnections within posterior networks, involving both intra-hemispheric and inter-hemispheric pathways. BFA was uniquely linked to an anterior lesion pattern centered on the ventral premotor cortex, driven by intrafrontal white matter disconnections. Furthermore, AOS emerged primarily as a focal cortical symptom linked to circumscribed lesions in the mid-precentral gyrus, with minimal structural disconnection. These findings demonstrate that LA emerges from disruptions within a widely distributed posterior network, whereas BFA involves an anterior intrafrontal network, contrasting with AOS which reflects a focal primary motor execution deficit. These data indicate that the neuroanatomical organization of apraxia is governed by the specific class of actions rather than simple effector specificity.

Emotions often occur within social interactions where affective cues are partly accessible or inferable by others. This raises theorethical questions regarding how and to what degree social context modulates subjective, physiological and behavioural affective responses, as well as their coherence, which remain points of tension in emotion research. To investigate this, we measured subjective affective ratings, autonomic sympathetic and parasympathetic activity, and facial behaviour while participants completed an emotion-induction task. In the social-context condition (but not control), participants believed that their video feed was accessible to a potential future interaction partner. Results show that even such "minimal social context" selectively and differentially modulated affective response modalities, characterised by both intensification of autonomic responses and dampening of overt facial and subjective affect. Multivariate dimensionality analysis further identified a cross-modal affective dimension. Notably, social context reduced participants' coupling with this shared affective response structure, indicating weaker cross-modal coherence. These findings suggest that emotional responding relies on a flexible, rather than rigid, configuration of affective features, likely recruited to meet the socioemotional demands of a given context. This has important implications for understanding the structure and function of emotion, as well as typical and atypical socioemotional responding.