The clinical evaluation of semantic knowledge has predominantly relied on tools targeting concrete concepts, whereas abstract knowledge has historically received limited attention despite its importance in everyday communication. Only a few instruments have explored the internal subdivision of abstract knowledge, likely due to the intrinsic difficulty of defining specific types of concepts or dimensions, resulting in a fragmented and heterogeneous neuropsychological assessment framework that limits our understanding of this domain. This systematic review examined the tools used to assess various types of abstract concepts in clinical populations. A literature search has been performed on the electronic databases of PubMed and Google Scholar (last update: October 2025). A total of 17 tests is reviewed, differing in the test characteristics, i.e. ranging from automatic to controlled processes and varying in ecological validity, the type of stimuli employed, and the abstract dimensions explored. Most studies have focused on neurodegenerative patients, while comparatively few have examined other clinical conditions. The risk of bias of the reviewed studies was assessed using an ad hoc developed instrument. This review highlights the need for future research to extend investigations to additional abstract domains and clinical populations, while also identifying key challenges related to stimulus selection and the determination of the most appropriate assessment framework.

Proactive control describes preparatory, anticipatory processes prior to upcoming demands, whereas reactive control is recruited as a late, corrective response to goal interferences. Here, we used fMRI to investigate behavioral and neuronal correlates of proactive and reactive control in major depressive disorder (MDD). Fifty patients and 50 healthy controls performed an antisaccade task with trial-specific central cues informing about the probability of upcoming task demands (antisaccade or prosaccade), thereby manipulating proactive control levels in the cue period. The trial-specific task instruction was contained in the peripheral stimulus, resulting in either congruent or incongruent trials in the saccadic response period to tax reactive control. Saccade stimuli were faces, with differently valenced expressions (negative, positive, neutral) allowing block-wise affective manipulation. Results indicated comparable effects of cue period proactive control in both groups in fronto-parieto-occipital cortex and striatum, including medial frontal and supplementary eye fields. In the response period, incongruent trials evoked enhanced activations in fronto-cingular, parietal and temporal cortex, thalamus and striatum, again without group differences. However, patients with MDD had larger antisaccade amplitudes and lower saccadic peak velocities. Exploratory analysis of a posterior parietal region-of-interest known to be related to non-standard sensorimotor transformations in antisaccades indicated reduced BOLD in patients during the response phase. There were no effects of stimulus valence on any measure. Together, these findings support the role of overlapping fronto-parieto-striatal networks in proactive and reactive control and suggest that in this particular task, such activations may be unaffected by stimulus-induced affective states as well as clinically relevant affective disorder.

A long-standing assumption in cognitive neuroscience is that visual mental imagery (VMI) is "visual perception in reverse" and, as such, requires reactivation of the primary visual cortex (V1). On this view, total destruction of V1 should abolish VMI and provoke neurological aphantasia. We tested this prediction by reviewing 55 published cases of cortical blindness (CB) in which VMI abilities were assessed. Vivid VMI is repeatedly documented in CB patients with complete or near-complete bilateral destruction, disconnection, or functional loss of V1; in impaired-VMI cases with informative anatomical or functional evidence, the lesion extends well beyond V1, typically into left temporal or temporo-occipital cortex. No impaired-VMI case with informative anatomical or functional evidence shows damage confined to V1. These data are difficult to reconcile with a necessary role for V1 in VMI. They are also compatible with, but do not by themselves establish, network accounts that assign an important role to ventral temporal and frontoparietal systems. We outline practical guidelines for future neuropsychological studies of visual mental imagery in CB.

To date, neurobiological accounts of lexical-semantic processing have largely assumed, either explicitly or implicitly, that there is no relationship between the sound of a word and its meaning, despite empirical evidence to the contrary. Recently, multiple representation theories have begun to incorporate non-arbitrary relationships in which a word's form resembles its meaning (iconicity). However, non-arbitrary form-meaning relationships occur more extensively within languages as statistical regularities between sublexical phonological/phonetic features and aspects of word meaning (systematicity or typicality). The present study investigated whether brain activity during lexical processing reflects statistical regularities between sublexical features and concrete and abstract concepts (i.e., concreteness form typicality). Twenty-one healthy participants completed an event-related functional magnetic resonance imaging (fMRI) study while they performed auditory lexical decisions on concrete and abstract words that were highly form-typical. We observed significant activity in a predominantly left-hemisphere network of perisylvian regions previously linked to concrete and abstract word processing. Crucially, the majority of these regions also responded to nonwords constructed with sublexical phonological/phonetic features associated with concreteness, including hub regions proposed to represent amodal conceptual processing. These findings demonstrate that statistical knowledge about non-arbitrary form-meaning mappings constitutes a core component of how concreteness is represented and accessed in the brain. We argue that these results support an account in which concrete and abstract concepts are grounded in the phonetic-acoustic features of language through statistical learning.

A growing literature examines the dimensionality of behavioral deficits in neurological populations using principal component analysis and related methods. Two opposing views have emerged. On one side, behavioral variability after brain injury (e.g., stroke, brain tumors, neurodegeneration) appears intrinsically low-dimensional, often captured by a few components. On the other side, this apparent simplicity has been attributed to lesion anatomy, task impurity, and methodological biases that may underestimate true dimensionality. Here both perspectives are summarized into a domain-dependent reconciliation. Cognitive performance measured with standard neuropsychological batteries may appear low-dimensional partly because tasks share common demands (e.g., attention, language, executive control), and because clinical severity induces correlated deficits that diminish with milder impairment. In contrast, motor behavior may be genuinely low-dimensional, reflecting biomechanical synergies. Thus, dimensionality is not a fixed property but depends on two interacting factors: disease severity and behavioral domain, offering a more nuanced framework for interpreting post-injury cognition.

During visual mental imagery, our eyes tend to reproduce patterns of movement similar to those observed in visual perception, even in the absence of external stimuli. However, imagery vividness varies along a spectrum, with congenital aphantasia at the lower extreme, where individuals report a reduced or absent ability to visualize voluntarily. Nevertheless, they can typically state from memory that Bordeaux is to the left of Paris on a map of France while denying having conjured any mental image. What cognitive mechanisms underlie this dissociation? Some theories suggest aphantasia stems from impaired image generation, while others propose it reflects a lack of metacognitive awareness of visual mental imagery. This study examines oculomotor patterns in aphantasia and visualizers during a mental exploration task involving an imagined map of France. We tested four competing hypotheses: H1: reduced eye movements in aphantasia are due to absent mental images; H2: increased exploratory eye movements in aphantasia as a sensorimotor compensatory strategy; H3: typical eye movements in aphantasia are associated with impaired metacognitive access, or H4: heterogeneous eye movement patterns in aphantasia. Results revealed that aphantasic individuals tended to look toward imagined targets just as visualizers do, consistent with H3. This suggests that congenital aphantasia is not the absence of visual mental images but may instead reflect reduced metacognitive access to imagery or a reliance on effective non-visual strategies capable of producing performance patterns similar to those of visualizers.

This study used event-related potentials to investigate the neural mechanisms underlying the target-location probability cueing effect, where repeated target appearance at one location improves visual search performance. We aimed to dissociate proactive spatial tuning (attentional enhancement before search array onset) from reactive enhancement (attentional improvement after onset). Behaviorally, targets at the high-probability location yielded significantly shorter reaction times, an effect that scaled with the strength of the spatial bias. Electrophysiologically, our probe-elicited N2pc analysis, intended to measure proactive tuning, yielded inconsistent results and was complicated by an unexpected negative-going baseline shift contralateral to the high-probability location. For reactive mechanisms, the target-elicited N2pc showed a surprising result: its amplitude decreased for targets at the high-probability location, contrary to the expected increase for efficient selection. Crucially, we observed the reliable emergence of an N1pc component at the high-probability location, an earlier marker of attentional selection (125-175 ms) that preceded the typical N2pc (175-255 ms). Latency analysis confirmed that the contralateral negativity onset was significantly earlier for high-probability targets compared to low-probability targets. These findings suggest that the behavioral benefit of target-location probability cueing is driven not by an increase in attentional resources (N2pc amplitude), but by a temporal acceleration of attentional deployment (N1pc presence and earlier latency) to the learned, high-probability location.

Moral dilemma evaluation depends on mental scene construction: people must build an internal event model specifying agents, spatial relations, and causal consequences. This process plausibly depends on visuospatial resources and self-regulatory control when imagined harm is affectively charged. This study tested whether individual differences in spatial visualization ability and impulsivity are associated with the representational format of moral simulation, specifically imagery vividness and simulated visual perspective, beyond endorsement rates. In an online sample (N = 156), participants were randomly assigned to either the Switch or Footbridge trolley dilemma and provided two judgments: moral acceptability and willingness to act. After each judgment, they reported imagery vividness, including a no-visual-imagery option, and simulated perspective (first-person vs third-person). Spatial visualization ability was assessed with the Spatial Visualization subtest of the INT, and impulsivity facets with the I-8. All inferential estimates were derived from bootstrap procedures (5,000 resamples), including mediation models testing whether vividness accounted for associations between individual differences and simulated perspective. In the high-conflict Footbridge dilemma, higher spatial visualization scores were associated with reduced imagery vividness and, in mediation models, with a greater likelihood of third-person simulation indirectly via lower vividness across both judgment contexts. By contrast, spatial visualization scores showed little association with endorsement rates. Impulsivity effects were selective: higher premeditation was associated with a lower likelihood of third-person simulation in Footbridge, especially for willingness-to-act judgments. These findings suggest that under heightened moral conflict, individual differences are more closely related to how moral scenes are represented than to binary moral choices.

Action control theories propose that both perceptual and action-related features of an action episode are temporarily bound together into event-files. When one of these features reappears, the corresponding event-file is retrieved, which can either facilitate or interfere with current performance depending on whether the retrieved and the current features match. Typically, partial repetitions of an event-file lead to slower responses and increased error rates compared to complete repetitions or complete changes (this phenomenon is labeled the 'binding effect'). The present study (n = 49) examined how perceptual salience influences the integration and retrieval of stimulus features within such event-files. Participants performed a sequential task in which an initially irrelevant stimulus could later become relevant, allowing us to assess how salience during binding shapes subsequent retrieval processes. Behaviorally, stronger binding effects emerged when the initially irrelevant stimulus had been salient compared to when it had been non-salient. At the neural level, this modulation was mirrored by enhanced theta-band activity over parieto-occipital regions during the probe display, consistent with the engagement of cognitive control mechanisms during event-file retrieval. Source localization further indicated that this theta modulation involved cingulate and supplementary motor areas, supporting their role in resolving interference between competing responses. Together, these findings suggest that perceptual salience strengthens the integration of stimulus features into event-files and/or event-file retrieval, enhancing subsequent retrieval-related conflict, observable both in behavioral performance and oscillatory activity.

Aphasia recovery has been widely studied, but evidence from underrepresented languages such as Hungarian remains limited. Intraindividual variability (IIV) has been proposed as a sensitive marker of long-term outcomes in neurological conditions, but its role in language recovery remains unknown. In the present study, participants completed experimental tasks targeting phonological, lexical, and semantic processing under varying working memory demands, with each task administered four times across four consecutive days. From these tasks, we derived accuracy (ACC), reaction time (RT), and IIV measures across and within sessions. This study examined (1) whether IIV explains variance in language recovery beyond accuracy (ACC) and reaction time (RT), and (2) which cognitive-linguistic abilities best predict post-stroke aphasia recovery. Forty-five individuals with post-stroke aphasia (21 female; age 57.29 ± 12.62 years; time post-onset 15.96 ± 39.10 months) were assessed twice, 13 months apart. Recovery outcomes were operationalized as language performance at the second time point, indexed separately by the Western Aphasia Battery Aphasia Quotient (WAB-AQ), the Comprehensive Aphasia Test (CAT) Total Score, and CAT Word Fluency. Three elastic net regression models with 10-fold cross-validation were compared: a Base model with ACC and RT, a Full model adding IIV, and a Final model that additionally included demographic and clinical variables. Phonological accuracy and baseline aphasia severity emerged as the most consistent and robust predictors. IIV did not consistently improve predictive performance and showed only limited, outcome-specific contributions. This study extends previous research on aphasia recovery and IIV to Hungarian, an underrepresented language in the aphasia literature.

Trust requires balancing potential mutual gain against possible betrayal. This decision depends not only on personal vulnerability to loss (risk) but also on the partner's incentive to betray (temptation) and whether the betrayal is committed intentionally (partner's agency). Previous research-limited by categorical behavioral designs and a neuroimaging focus on pathological mistrust-leaves it unclear how the brain systematically represents personal risk, partner's temptation, and partner's agency during typical trust decisions. We used functional magnetic resonance imaging with a parametric binary trust game to disentangle the effects of these factors. Thirty-one participants made binary trust decisions while these factors were systematically varied. Behaviorally, trust declined with increasing risk and with the risk × temptation interaction, owing to self-centered heuristics, while agency had no reliable effect. Neurally, risk was encoded in a decision-dependent manner: increasing risk in trust engaged the salience network (anterior mid-cingulate cortex), whereas in non-trust it recruited striato-motor circuits (putamen, motor cortex). Temptation, in interaction with risk, was represented independently of choice, expressed as increased activity in Calcarine but reduced activity in the medial prefrontal hub of the default mode network. Agency was distinguished neurally in the dorsomedial prefrontal cortex despite absent behavioral effects. Exploratory analyses showed that trust versus non-trust engaged distinct large-scale networks, with trust recruiting the central-executive and salience networks and non-trust the posterior default-mode network. These findings reveal distinct neural signatures for vulnerability, partner incentives, and partner agency in trust decisions, highlighting how self- and other-focused factors are encoded differently across large-scale brain networks.

Reading and writing impairments are frequent in primary progressive aphasia (PPA), yet their characterization in Spanish-speaking populations remains limited due to language-specific orthographic properties. The present study examined reading and writing impairments in 17 Spanish-speaking participants diagnosed with PPA (9 logopenic, 4 semantic, and 4 nonfluent), with the aim of identifying patterns of acquired dyslexia and dysgraphia across PPA variants. A single-case series design was employed, including individuals diagnosed with PPA and matched healthy control subjects. Participants were assessed using tasks of word and nonword reading, loanword reading, visual lexical decision with pseudohomophones, and writing to dictation of words and nonwords. Results showed that 94% of participants presented acquired dyslexia and 75% acquired dysgraphia. Both impairments were observed across all PPA variants. Regarding reading profiles, five cases of surface acquired dyslexia, two of phonological dyslexia, three of mixed dyslexia, and six unspecified profiles were identified. In writing, one case of surface acquired dysgraphia, one phonological, four mixed, and six unspecified profiles were observed. These findings provide relevant evidence regarding the presence and heterogeneity of acquired dyslexia and dysgraphia in Spanish-speaking individuals with PPA, and demonstrate that these patterns can be systematically identified when assessment procedures account for the linguistic characteristics of Spanish and the clinical features of this population.

Some individuals with aphantasia, an absent or reduced ability to form visual imagery, report face recognition difficulties, and studies have shown aphantasics exhibit impaired face recognition performance on the Cambridge Face Memory Test. While this impaired performance may be due to poor face memory, it may instead, or in addition, be due to difficulties in other face processing domains (such as face perception or face matching). The Cambridge Face Memory Test, Oxford Face Matching Test and a novel analysis strategy were used to obtain independent measures of face memory, face matching and face perception from 34 individuals with aphantasia and an age-matched control group. Results showed that individuals with aphantasia exhibit impairments in face memory and face perception, but not face matching. This study therefore provides information about the specific face processing mechanisms that may be impaired in aphantasia.