Cognitive and affective theory of mind double dissociation after parietal and temporal lobe tumours.

Extensive neuroimaging literature suggests that understanding others' thoughts and emotions engages a wide network encompassing parietal, temporal and medial frontal brain areas. However, the causal role played by these regions in social inferential abilities is still unclear. Moreover very little is known about theory of mind deficits in brain tumours and whether potential anatomical substrates are comparable to those identified in functional MRI literature. This study evaluated the performance of 105 tumour patients, before and immediately after brain surgery, on a cartoon-based non-verbal task evaluating cognitive (intention attribution) and affective (emotion attribution) theory of mind, as well as a non-social control condition (causal inference). Across multiple analyses, we found converging evidence of a double dissociation between patients with right superior parietal damage, selectively impaired in intention attribution, and those with right anteromedial temporal lesion, exhibiting deficits only in emotion attribution. Instead, patients with damage to the frontal cortex were impaired in all kinds of inferential processes, including those from the non-social control conditions. Overall, our data provide novel reliable causal evidence of segregation between different aspects of the theory of mind network from both the cognitive and also the anatomical point of view.

Medial orbital gyrus modulation during spatial perspective changes: Pre- vs. post-8 weeks mindfulness meditation.

Mindfulness meditation exercises the ability to shift to an "observer perspective". That means learning to observe internally and externally arising stimulations in a detached perspective. Both before and after attending a 8-weeks mindfulness training (MT) participants underwent an fMRI experiment (serving as their own internal control) and solved a own-body mental transformation task, which is used to investigate embodiment and perspective taking (and an non-bodily mental transformation task as control). We found a stimulus×time-points interaction: the own-body mental transformation task (vs. non-bodily) in the post (vs. pre-MT) significantly increased activations in the medial orbital gyrus. The signal change in the right medial orbital gyrus significantly correlated with changes in a self-maturity personality scale. A brief MT caused increased activation in areas involved in self related processing and person perspective changes, together with an increase in self-maturity, consistently with the aim of mindfulness meditation that is exercising change in self perspective.

Impact of brain tumour location on emotion and personality: a voxel-based lesion-symptom mapping study on mentalization processes.

Patients affected by brain tumours may show behavioural and emotional regulation deficits, sometimes showing flattened affect and sometimes experiencing a true 'change' in personality. However, little evidence is available to the surgeon as to what changes are likely to occur with damage at specific sites, as previous studies have either relied on single cases or provided only limited anatomical specificity, mostly reporting associations rather than dissociations of symptoms. We investigated these aspects in patients undergoing surgery for the removal of cerebral tumours. We argued that many of the problems described can be ascribed to the onset of difficulties in one or more of the different levels of the process of mentalizing (i.e. abstracting and reflecting upon) emotion and intentions, which impacts on everyday behaviour. These were investigated in terms of (i) emotion recognition; (ii) Theory of Mind; (iii) alexithymia; and (iv) self-maturity (personality disorder). We hypothesized that temporo/limbic areas would be critical for processing emotion and intentions at a more perceptual level, while frontal lobe structures would be more critical when higher levels of mentalization/abstraction are required. We administered four different tasks, Task 1: emotion recognition of Ekman faces; Task 2: the Eyes Test (Theory of Mind); Task 3: Toronto Alexithymia Scale; and Task 4: Temperament and Character Inventory (a personality inventory), both immediately before and few days after the operation for the removal of brain tumours in a series of 71 patients (age range: 18-75 years; 33 female) with lesions located in the left or right frontal, temporal and parietal lobes. Lobe-based and voxel-based analysis confirmed that tasks requiring interpretation of emotions and intentions at more basic (less mentalized) levels (Tasks 1 and 2) were more affected by temporo/insular lesions, with emotion recognition (Task 1) being maximally impaired by anterior temporal and amygdala lesions and Task 2 (found to be a 'basic' Theory of Mind task involving only limited mentalization) being mostly impaired by posterior temporoparietal lesions. Tasks relying on higher-level mentalization (Tasks 3 and 4) were maximally affected by prefrontal lesions, with the alexithymia scale (Task 3) being mostly associated with anterior/medial lesions and the self-maturity measure (Task 4) with lateral prefrontal ones.

Effects of an 8-week meditation program on the implicit and explicit attitudes toward religious/spiritual self-representations.

Explicit self-representations often conflict with implicit and intuitive self-representations, with such discrepancies being seen as a source of psychological tension. Most of previous research on the psychological effects of mindfulness-meditation has assessed people's self-attitudes at an explicit level, leaving unknown whether mindfulness-meditation promotes changes on implicit self-representations. Here, we assessed the changes in implicit and explicit self-related religious/spiritual (RS) representations in healthy participants following an 8-week mindfulness-oriented meditation (MOM) program. Before and after meditation, participants were administered implicit (implicit association test) and explicit (self-reported questionnaires) RS measures. Relative to control condition, MOM led to increases of implicit RS in individuals whit low pre-existing implicit RS and to more widespread increases in explicit RS. On the assumption that MOM practice may enhance the clarity of one's transcendental thoughts and feelings, we argued that MOM allows people to transform their intuitive feelings of implicit RS as well as their explicit RS attitudes.

Mindfulness-oriented meditation improves self-related character scales in healthy individuals.

Previous studies have shown that mindfulness meditation may improve well-being in healthy individuals and be effective in the treatment of mental and neurological disorders. Here, we investigated the effects of an 8-week mindfulness-mediation program on the personality profiles of three groups of healthy individuals with no previous experience with meditation as compared to a control group not enrolled in any training. Personality profiles were obtained through the Temperament and Character Inventory (Cloninger et al., 1993). In the experimental groups, significant increments after the training were obtained in all the three character scales describing the levels of self maturity at the intrapersonal (Self-Directedness), interpersonal (Cooperativeness), and transpersonal (Self-Transcendence) levels. No changes were found in the control group. Strikingly, these effects were significant only in those groups who were engaged in consistent daily meditation practice but not in the group who attended the meditation training but were less consistent in home practice. Since higher scores in the character scales are associated to a lower risk of personality disorder, we propose that the increase of self maturity after the training may be an important mechanism for the effectiveness of mindfulness-oriented meditation in psychotherapeutic contexts.

Genomic analysis of NE Atlantic sardine (Sardina pilchardus) reveals reduced variation in a recently established North Sea population and directs reconsideration of management units.

The European sardine (Sardina pilchardus) is under intense fishing pressure and exhibits distributional/abundance shifts linked to environmental change. The current understanding of population demographics needed for sustainable management is uncertain due to concerns that previous genetic studies lacked resolution and limited sampling of sardine north of the Bay of Biscay. To address these issues, we performed mtDNA sequencing and genome wide SNP analysis of samples collected across the Bay of Biscay, Celtic Sea, English Channel and North Sea. The complete SNP data reported a lack of structure throughout the sampled area compatible with high gene flow. A consensus suite of positive outlier SNPs was identified which reported a significant correlation with geographical distance with the largest differentiation between the southern Bay of Biscay and North Sea samples which also reported a significant mtDNA ΦST. While the roles of dispersal limitation and environmental heterogeneity underpinning this require further study, this adds to growing evidence that selection is influencing sardine population structure against a background of high gene flow. The results indicate that while there may be a level of demographic independence between North Sea and South Biscay sardine, the current delimitation of central (Biscay) and northern (Channel and Celtic Sea) operational stocks may misrepresent connectivity between the Biscay and Channel. The North Sea sample exhibited markedly lower mtDNA and nuclear variation than other samples. As sardine have only recently invaded the North Sea such reduced genetic variation is compatible with predictions for peripheral leading-edge populations but contrasts with patterns for other small pelagic species and emphasises the need to consider species-specific genetic structure in ecosystem-based management. Nascent management of the North Sea sardine fishery must ensure that current low levels of genetic diversity are not eroded further as this may decrease the species adaptive potential and inhibit its expansion.

Refractory semantic access dysphasia resulting from resection of a left frontal glioma.

The existence of semantic access disorders is now well established, however the precise cognitive and anatomical underpinnings are still debated. Here we describe the case of a patient that became aphasic after the resection of a left frontal glioma. Detailed lesion reconstruction indicates that the lesion was mostly restricted to the left dorsal and ventral prefrontal cortices and the underlying white matter, but sparing temporal lobes. Critically, the patient showed all the signs of refractory semantic access dysphasia, supporting the association between this syndrome and damage to left prefrontal areas likely to subserve retrieval and selection mechanisms for verbal material.

Health professionals who have worked in COVID-19 immunization centers suffer the effects of violence.

Background: The phenomenon violence against health professionals has received increasing attention in recent years because of its frequency and significant impact on victims' mental health and disruption of health services. Despite this attention, little is known about the incidence of workplace violence in the highly politicized immunization services. Therefore, we decided to examine the prevalence of workplace violence in the COVID-19 immunization campaign, the risk and protective factors, and the impact on victims' mental health. Methods: Between March and April 2022, we conducted an anonymous online survey among health professionals working in COVID-19 vaccination centers in the Friuli-Venezia Giulia Region (Italy). We used the Questionnaire for Workplace Violence in Healthcare Settings and the Impact of Event Scale-Revised. Results: Of the 200 participants, 93 (46.5%) reported being victims of an act of violence during the vaccination campaign, 60 of them verbally and 7 physically. In 35.5% of cases, the IES score indicated a possible post-traumatic stress reaction in the victim. Opinions on measures to prevent violence and support workers in the workplace differed according to the sex of the health professional, with women emphasizing the need for self-defense training and improvement of security arrangements (p < 0.001). Conclusion: One-third of health professionals involved in the COVID-19 immunization campaign reported that their mental health was affected by workplace violence. Public health professionals dealing with politicized and debated issues such as immunization should receive more attention, as should the implementation of a more structured and multidisciplinary approach to the problem within healthcare organizations.

Manipulability and object recognition: is manipulability a semantic feature?

Several lines of evidence exist, coming from neuropsychology, neuroimaging and behavioural investigations on healthy subjects, suggesting that an interaction might exist between the systems devoted to object identification and those devoted to online object-directed actions and that the way an object is acted upon (manipulability) might indeed influence object recognition. In this series of experiments on speeded word-to-picture-matching tasks, it is shown how the presentation of pairs of objects sharing similar manipulation causes greater interference with respect to objects sharing only visual similarity (experiment 1). Moreover, (experiment 2) it is shown how the repeated presentation of pairs of objects sharing a similar type of manipulation leads to a 'negative' serial position effect, with the number of errors increasing across presentations, a behaviour that is typically found in patients with access deficits to semantic representations. By contrast, the repeated presentation of pairs of objects sharing only visual similarity leads to an opposite 'positive' serial position effect, with errors decreasing across presentations. It is argued that a negative serial position effect is linked to interference occurring within the semantic system, and therefore that the way an object is manipulated is indeed a semantic feature, critical in defining manipulable object properties at a semantic level. To our knowledge, this constitutes the first direct evidence of manipulability being a semantic dimension. The results are discussed in the light of current models of semantic memory organization.

Cognitive reserve protects language functions in patients with brain tumours.

Cognitive reserve (CR) theory suggests that individual differences in general intelligence (IQ), occupational attainment or participation in leisure/recreational activities protect against cognitive decline. However the relationship between CR and cognitive functioning in patients with brain tumours has been very rarely investigated in past research. The present study systematically assesses whether CR concept can also be applied to cognitive functions of neurosurgical patients affected by brain tumours. We investigated the role of different CR proxies (education level, premorbid IQ, current IQ, working and leisure activity) in protecting language against brain tumours and surgery effects, considering interactions with demographic (sex/age), anatomical (hemisphere/lobe location of lesion) and clinical/biological variables (tumour type: High/Low Grade Glioma or Meningioma; lesion volume; lesion aggressiveness). One-hundred patients undergoing neuropsychological assessment before and immediately after surgery participated. A "Language Score" summarizing performance on all language tests was derived with Principal Component Analysis. Data were then analyzed with Multiple Regression and Classification and Regression Tree analyses to investigate possible relationships between predictors (CR proxies and clinical variables) and Language Score. We found that premorbid IQ was the best predictor of pre-operatory language integrity, above and beyond all clinical variables considered, also moderating lesion volume effects. Moreover, patients with lower pre-operatory language integrity and low-to-moderately aggressive tumours showed a mitigating effect of current IQ over surgery consequences. Results thus suggest that different CR proxies play a role in moderating cognitive decline following brain tumours and surgery.

Semantic access dysphasia resulting from left temporal lobe tumours.

Unlike semantic degradation disorders, the mechanisms and the anatomical underpinnings of semantic access disorders are still unclear. We report the results of a case series study on the effects of temporal lobe gliomas on semantic access abilities of a group of 20 patients. Patients were tested 1-2 days before and 4-6 days after the removal of the tumour. Their semantic access skills were assessed with two spoken word-to-picture matching tasks, which aimed to separately control for rate of presentation, consistency and serial position effects (Experiment 1) and for word frequency and semantic distance effects (Experiment 2). These variables have been held to be critical in characterizing access in contrast to degraded-store semantic deficits, with access deficits characterized by inconsistency of response, better performance with slower presentation rates and with semantically distant stimuli, in the absence of frequency effects. Degradation deficits show the opposite pattern. Our results showed that low-grade slowly growing tumours tend not to produce signs of access problems. However, high-grade tumours especially within the left hemisphere consistently produce strong semantic deficits of a clear access type: response inconsistency and strong semantic distance effects in the absence of word frequency effects were detected. However, effects of presentation rate and serial position were very weak, suggesting non-refractory behaviour in the tumour patients tested. This evidence, together with the results of lesion overlapping, suggests the presence of a type of non-refractory semantic access deficit. We suggest that this deficit could be caused by the disconnection of posterior temporal lexical input areas from semantic system.

Dynamics of predator-prey habitat use and behavioral interactions over diel periods at sub-tropical reefs.

The dynamics of fish communities at tropical and sub-tropical rocky reefs are influenced in many cases by predation activity and predator-prey interactions. These processes usually follow specific diel patterns in reef areas with higher rates of these interactions occurring during the crepuscular periods. However, other factors such as habitat complexity and species-specific behavior may alter these patterns, increasing variability in species interactions. A better understanding of the dynamics of these patterns and processes would allow us to manage and monitor fish communities in these productive and vulnerable areas more efficiently. We investigated behavioral changes of predators and prey fish in sub-tropical "live-bottom" (sandstone) reefs at Gray's Reef National Marine Sanctuary (GRNMS), located 20 nautical miles off the coast of Georgia, USA, using fisheries acoustic methods in association with visual census and direct observation using SCUBA. Changes in co-location and habitat preferences of predators and prey over time throughout the diel cycle were investigated using species distribution models (MAXENT) based on habitat predictors and by means of spatial statistics. The results indicate that predator and prey distribution patterns changed considerably throughout the day. Prey and predator species exhibited complex spatial dynamics and behavior over diel periods, with prey modifying patterns of habitat use and spatial distribution, likely as a response of their interactions with predators. Crepuscular periods were confirmed to be the most active phases in terms of predator-prey interactions and consequently the most variable. The combination of tools and approaches used in this study provided valuable sources of information that support the inferences of predation risk-driven habitat selection of prey in this sub-tropical reef system.

Localizing Memory Functions in Brain Tumor Patients: Anatomical Hotspots over 260 Patients.

OBJECTIVE: Memory complaints are common in patients after brain tumor, but is difficult to map memory functions during awake surgery, to preserve them. Thus we analyzed one of the largest data sets on clinical, surgical, and anatomical correlates of memory in patients with brain tumor to date, providing anatomical hotspots for short and long-term memory functions. METHODS: A total of 260 patients with brain tumor (130 high-grade gliomas; 76 low-grade gliomas [LGG]; 54 meningiomas) were tested on 2 commonly used short-term memory (Digit Span Forward and Corsi Spatial Span) and 2 long-term memory tasks (Narrative Memory and Delayed Recall of Rey Figure). Patients were evaluated before and immediately after surgery and (for LGG) after 4 months and data analyzed by means of analysis of covariance and the voxel-based lesion-symptom mapping technique. RESULTS: As expected, patients with high-grade gliomas were already impaired before surgery, whereas patients with meningioma were largely unimpaired. Patients with LGG were unimpaired before surgery, but showed significant performance drop immediately after, with good recovery within few months. Voxel-based lesion-symptom mapping analyses identified specific anatomical correlates for verbal memory tasks, whereas visuospatial tasks provided good sensitivity to cognitive damage but failed to show anatomical specificity. Anatomical hotspots identified were in line with both previous functional magnetic resonance imaging and clinical studies on other neurological populations. CONCLUSIONS: Verbal memory tasks revealed a set of specific anatomical hotspots that might be considered "eloquent" for verbal memory functions, unlike visuospatial tasks, suggesting that commonly used spatial memory tasks might not be optimal to localize the damage, despite an otherwise good sensitivity to cognitive damage.

Emotional concerns and coping strategies in Low Grade Glioma patients and reliability of their caregivers in reporting these concerns: Findings from a cross-sectional study.

PURPOSE: To explore the emotional concerns and coping strategies of patients with Low Grade Glioma (LGG) and whether or not their caregivers are reliable in reporting these concerns as surrogate informants. METHODS: An explorative cross-sectional study. Patients who had undergone a neurosurgical procedure at least one year before this study for LGG and who were capable of participating in a face-to-face interview were included. Each patient nominated a reference caregiver. Both the patient and the caregiver were interviewed independently, using the Beck Depression Inventory Scale, the State - Trait Anxiety Inventory, and the Jalowiec Coping Scale. MAIN RESULTS: Forty-six patients and 46 caregivers were included. The average scores of the Beck scale were homogeneous between patients and caregivers (7.76 [CI 95% 5.76-9.75] vs. 6.23 [CI 95% 4.57-7.90]; p = 0.102). Patients reported significantly greater state and trait anxiety (44.26 [CI 95% 40.21-48.31] and 37.95 [CI 95% 34.97-40.94]), respectively compared to their caregivers (40.28 [CI 95% 36.64-43.91] and 35.17 [CI 95% 32.16-38.18]). The coping strategies enacted were homogeneous between patients and caregivers (82.78 [CI 95% 77.21-88.35] vs (80.93 [CI 95% 76.32-85.55]; p = 0.102) while the kind of strategies adopted were significantly diverse. CONCLUSIONS: Patients suffer from depression and greater state anxiety as compared to trait anxiety; moreover, they enact less than half of the available coping strategies. Caregivers may be involved as surrogate informants when necessary for health-care professionals to detect depression while more caution is advised for what concerns anxiety and the coping strategies enacted by patients.

Long-Term Cognitive Functioning and Psychological Well-Being in Surgically Treated Patients with Low-Grade Glioma.

OBJECTIVE: The aim of this work is to provide an in-depth investigation of the impact of low-grade gliomas (LGG) and their surgery on patients' cognitive and emotional functioning and well-being, carried out via a comprehensive and multiple-measure psychological and neuropsychological assessment. PATIENTS AND METHODS: Fifty surgically treated patients with LGG were evaluated 40 months after surgery on their functioning over 6 different cognitive domains, 3 core affective/emotional aspects, and 3 different psychological well-being measures to obtain a clearer picture of the long-term impact of illness and surgery on their psychological and relational world. Close relatives were also involved to obtain an independent measure of the psychological dimensions investigated. RESULTS: Cognitive status was satisfactory, with only mild short-term memory difficulties. The affective and well-being profile was characterized by mild signs of depression, good satisfaction with life and psychological well-being, and good personality development, with patients perceiving themselves as stronger and better persons after illness. However, patients showed higher emotional reactivity, and psychological well-being measures were negatively affected by epileptic burden. Well-being was related to positive affective/emotional functioning and unrelated to cognitive functioning. Good agreement between patients and relatives was found. CONCLUSIONS: In the long-term, patients operated on for LGG showed good cognitive functioning, with no significant long-term cognitive sequelae for the extensive surgical approach. Psychologically, patients appear to experience a deep psychological change and maturation, closely resembling that of so-called posttraumatic growth, which, to our knowledge, is for the first time described and quantified in patients with LGG.

Speed-accuracy strategy regulations in prefrontal tumor patients.

The ability to flexibly switch between fast and accurate decisions is crucial in everyday life. Recent neuroimaging evidence suggested that left lateral prefrontal cortex plays a role in switching from a quick response strategy to an accurate one. However, the causal role of the left prefrontal cortex in this particular, non-verbal, strategy switch has never been demonstrated. To fill this gap, we administered a perceptual decision-making task to neuro-oncological prefrontal patients, in which the requirement to be quick or accurate changed randomly on a trial-by-trial basis. To directly assess hemispheric asymmetries in speed-accuracy regulation, patients were tested a few days before and a few days after surgical excision of a brain tumor involving either the left (N=13) or the right (N=12) lateral frontal brain region. A group of age- and education-matched healthy controls was also recruited. To gain more insight on the component processes implied in the task, performance data (accuracy and speed) were not only analyzed separately but also submitted to a diffusion model analysis. The main findings indicated that the left prefrontal patients were impaired in appropriately adopting stricter response criteria in speed-to-accuracy switching trials with respect to healthy controls and right prefrontal patients, who were not impaired in this condition. This study demonstrates that the prefrontal cortex in the left hemisphere is necessary for flexible behavioral regulations, in particular when setting stricter response criteria is required in order to successfully switch from a speedy strategy to an accurate one.

Acute effects of surgery on emotion and personality of brain tumor patients: surgery impact, histological aspects, and recovery.

BACKGROUND: Cognitive effects of brain surgery for the removal of intracranial tumors are still under investigation. For many basic sensory/motor or language-based functions, focal, albeit transient, cognitive deficits have been reported low-grade gliomas (LGGs); however, the effects of surgery on higher-level cognitive functions are still largely unknown. It has recently been shown that, following brain tumors, damage to different brain regions causes a variety of deficits at different levels in the perception and interpretation of emotions and intentions. However, the effects of different tumor histologies and, more importantly, the effects of surgery on these functions have not been examined. METHODS: The performance of 66 patients affected by high-grade glioma (HGG), LGG, and meningioma on 4 tasks tapping different levels of perception and interpretations of emotion and intentions was assessed before, immediately after, and (for LGG patients) 4 months following surgery. RESULTS: Results showed that HGG patients were generally already impaired in the more perceptual tasks before surgery and did not show surgery effects. Conversely, LGG patients, who were unimpaired before surgery, showed a significant deficit in perceptual tasks immediately after surgery that was recovered within few months. Meningioma patients were substantially unimpaired in all tasks. CONCLUSIONS: These results show that surgery can be relatively safe for LGG patients with regard to the higher-level, more complex cognitive functions and can provide further useful information to the neurosurgeon and improve communication with both the patient and the relatives about possible changes that can occur immediately after surgery.

The neural network associated with lexical-semantic knowledge about social groups.

A person can be appraised as an individual or as a member of a social group. In the present study we tested whether the knowledge about social groups is represented independently of the living and non-living things. Patients with frontal and temporal lobe tumors involving either the left or the right hemisphere performed three tasks--picture naming, word-to-picture matching and picture sorting--tapping the lexical semantic knowledge of living things, non-living things and social groups. Both behavioral and voxel-based lesion-symptom mapping (VLSM) analyses suggested that social groups might be represented differently from other categories. VLSM analysis carried out on naming errors revealed that left-lateralized lesions in the inferior frontal gyrus, amygdala, insula and basal ganglia were associated with the lexical-semantic processing of social groups. These findings indicate that the social group representation may rely on areas associated with affective processing.

Cognitive and anatomical underpinnings of the conceptual knowledge for common objects and familiar people: a repetitive transcranial magnetic stimulation study.

Several studies have addressed the issue of how knowledge of common objects is organized in the brain, whereas the cognitive and anatomical underpinnings of familiar people knowledge have been less explored. Here we applied repetitive transcranial magnetic stimulation (rTMS) over the left and right temporal poles before asking healthy individuals to perform a speeded word-to-picture matching task using familiar people and common objects as stimuli. We manipulated two widely used semantic variables, namely the semantic distance and the familiarity of stimuli, to assess whether the semantic organization of familiar people knowledge is similar to that of common objects. For both objects and faces we reliably found semantic distance and familiarity effects, with less accurate and slower responses for stimulus pairs that were more closely related and less familiar. However, the effects of semantic variables differed across categories, with semantic distance effects larger for objects and familiarity effects larger for faces, suggesting that objects and faces might share a partially comparable organization of their semantic representations. The application of rTMS to the left temporal pole modulated, for both categories, semantic distance, but not familiarity effects, revealing that accessing object and face concepts might rely on overlapping processes within left anterior temporal regions. Crucially, rTMS of the left temporal pole affected only the recognition of pairs of stimuli that could be discriminated at specific levels of categorization (e.g., two kitchen tools or two famous persons), with no effect for discriminations at either superordinate or individual levels. Conversely, rTMS of the right temporal pole induced an overall slowing of reaction times that positively correlated with the visual similarity of the stimuli, suggesting a more perceptual rather than semantic role of the right anterior temporal regions. Results are discussed in the light of current models of face and object semantic representations in the brain.

Refractoriness and the healthy brain: a behavioural study on semantic access.

While many behavioural studies on refractory phenomena in lexical/semantic access have focused on the mechanisms involved in the oral production of names, comprehension tasks have been almost exclusively used in neuropsychological studies on brain damaged patients. We report the results of two experiments on healthy participants conducted by means of speeded word to picture matching tasks. They assess the effects of the same variables examined in the study of refractory access dysphasic patients: semantic distance and word frequency (experiment 1) and presentation rate and serial position effects (experiment 2). Semantic access patients usually show little effect of word frequency but a large semantic distance effect. However, critical in characterising the syndrome as 'refractory', effects of presentation rate and serial position should also be present. The experiments involved the use of a deadline response procedure. The critical manipulation was the absence of a Response Stimulus Interval (RSI) in the fast presentation rate conditions; slower presentation rates involved 1 s RSI. With these manipulations the typical behavioural pattern of performance provided by semantic access dysphasic patients was reproduced. Semantic distance effects were more powerful than word frequency effects (experiment1). Presentation rate effects were found and, most important for a "refractory" account of the effects, a serial position effect was obtained (experiment 2). These results provide the first evidence of such a broad range of refractory effects at the same time in comprehension tasks in healthy subjects and support a purely semantic account for the locus of refractoriness. Moreover, error analysis showed a predominance of perseverative errors with subsequent representations of the same target, supporting a failure of cognitive control mechanisms as the cause of refractory behaviour. The findings are discussed in the light of current models of lexical and semantic processing.