Contribution of different regions of the prefrontal cortex and lesion laterality to deficit of decision-making on the Iowa Gambling Task.

Few studies have examined the contribution of different sub-regions of the prefrontal cortex and lesion laterality to decision-making abilities. In addition, there are inconsistent findings about the role of ventromedial and dorsolateral lesions in decision-making deficit. In this study, decision-making processes are investigated following different damaged areas of the prefrontal cortex. We paid particular attention to the contribution of laterality, lesion location and lesion volume in decision-making deficit. Twenty-seven patients with discrete ventromedial lesions, dorsolateral lesions or extended-frontal lesions were compared with normal subjects on the Iowa Gambling Task (IGT). Our results showed that all frontal subgroups were impaired on the IGT in comparison with normal subjects. We noted also that IGT performance did not vary systematically based on lesion laterality or location. More precisely, our lesion analysis revealed that decision-making processes depend on a large cerebral network, including both ventromedial and dorsolateral areas of the prefrontal cortex. Consistent with past findings, our results support the claim that IGT deficit is not solitarily associated with ventromedial prefrontal cortex lesions.

Pragmatic language comprehension: Role of theory of mind, executive functions, and the prefrontal cortex.

The specific contribution of focal damage of the prefrontal cortex and the cognitive mechanisms accounting for communicative-pragmatic disorders remains unclear. The objective of the current study was to investigate the impact of focal prefrontal cortex damage on the ability to understand indirect speech or hints and to identify the prefrontal neural mechanisms involved. We also examined the underlying cognitive mechanisms of disorders of indirect speech understanding particularly theory of mind and executive functions. Thirty patients with focal prefrontal cortex damage and 30 control subjects were compared on their performances on the Hinting task assessing pragmatic language skills, the "Faux-Pas" task and the Reading the Mind in the Eyes task assessing Theory of Mind and a battery of executive tasks. Patients were significantly impaired compared with control subjects on all these abilities. Both deficits of executive functions and theory of mind were able to predict impaired ability of patients in understanding non-literal meanings on the Hinting task. Finally, using voxel-based lesion analysis we identified a partially shared neural prefrontal network involved in all these abilities centered on the dorsomedial and ventral regions of the prefrontal cortex.

Role of the prefrontal cortex and executive functions in basic emotions recognition: evidence from patients with focal damage to the prefrontal cortex.

Few studies have examined the specific contribution of focal damage of the prefrontal cortex and executive dysfunction to emotion recognition deficits, with results reporting controversial findings. This study investigated the performance of 30 patients with prefrontal cortex damage and 30 matched controls on a battery of executive measures assessing processes of inhibition, flexibility, and planning and a task of emotion recognition with also a particular attention to the examination of the association between these domains. The results showed that compared with control participants, patients with prefrontal cortex damage were impaired in recognizing the three negative emotions of fear, sadness, and anger and were also impaired on all executive measures. Moreover, by examining the association between both these domains, using correlation and regression analyses, we noted that impaired performance in recognizing emotions of fear, sadness, and anger was predicted by impaired performances on the measures of inhibition and flexibility or "set-shifting" suggesting that the ability to recognize emotions could be at least to some extent cognitively mediated. Finally, using a voxel-based lesion technique, we identified a partially common prefrontal network underlying deficits on executive functions and emotions recognition centered on the ventral and medial parts of the prefrontal cortex, reflecting beyond the neural network involved in recognizing negative emotions per se that of the cognitive processes elicited by this emotion task.

Exploring behavioural and cognitive dysexecutive syndrome in patients with focal prefrontal cortex damage.

This study's objectives were to characterize the frequency and profile of behavioral and cognitive dysexecutive syndromes in patients with focal prefrontal cortex damage and how these syndromes overlap. We also examined the contribution of the prefrontal brain regions to these syndromes. Therefore, thirty patients with prefrontal cortex damage and thirty control subjects were compared on their performances using the GREFEX battery assessing the dysexecutive syndromes. The results showed that combined behavioral and cognitive dysexecutive syndrome was observed in 53.33%, while pure cognitive dysexecutive syndrome was observed in 20% and behavioral in 26.67%. Also, almost all behavioral and cognitive dysexecutive disorders discriminated frontal patients from controls. Moreover, correlations and regression analyses between task scores in both domains of dysexecutive syndromes showed that the spectrum of behavioral disorders was differentially associated with cognitive impairment of initiation, inhibition, generation, deduction, coordination, flexibility and the planning process. Furthermore, the patterns of cognitive and behavioral dysexecutive syndrome were both predictors of impairment in daily living activities and loss of autonomy. Finally, frontal regions contributing to different dysexecutive syndromes assessed by MRI voxel lesion symptom analysis indicate several overlapping regions centered on the ventromedial and dorsomedial prefrontal cortex for both domains of dysexecutive syndrome. This study concludes that damage to the frontal structures may lead to a diverse set of changes in both cognitive and behavioral domains which both contribute to loss of autonomy. The association of the ventromedial and dorsomedial prefrontal regions to both domains of dysexecutive syndrome suggests a higher integrative role of these regions in processing cognition and behavior.

Neurocognitive and neural mechanisms underlying deficit on the Reading Mind In The Eyes Task: Evidence from patients with focal prefrontal cortex damage.

OBJECTIVE: Conflicting evidence has arisen from the few correlational studies that have examined the relationship between the ability to decode social emotional cues through the eyes and executive functions in individuals with prefrontal cortex damage. The objective of the current study was (1) to investigate the impact of both focal prefrontal and parietal cortex damage on both of these domains; (2) to examine whether impaired ability to decode social emotion cues through the eyes was predicted by executive function deficits and; (3) to explore the neural correlates of both of these components. METHOD: Thirty individuals with prefrontal cortex damage, 15 individuals with parietal cortex damage and 30 matched healthy comparison subjects were subjected to a battery of executive tasks assessing inhibition, flexibility, and planning processes and the Reading the Mind in the Eyes Task (RMET) assessing ability to decode social emotion cues through the eyes. RESULTS: Compared to both comparison groups, individuals with prefrontal cortex damage were impaired in performing RMET and almost all executive tasks. Regression analysis showed that for individuals with prefrontal cortex damage, performance on the Stroop and Hayling tasks predicted scores on the RMET, while for the healthy comparison group, only the verbal fluency performance predicted scores on the RMET. The Voxel lesions-symptom mapping technique showed that both components rely partly on the same neural substrates, reflecting beyond the neural network of RMET per se that of the cognitive processes elicited by this multi-determinant task. CONCLUSION: These findings suggest that the ability to read mental states of mind depends on the inhibition and flexibility executive mechanisms.

Impaired Perception of Unintentional Transgression of Social Norms after Prefrontal Cortex Damage: Relationship to Decision Making, Emotion Recognition, and Executive Functions.

OBJECTIVE: Patients with prefrontal cortex damage often transgress social rules and show lower accuracy in identifying and explaining inappropriate social behavior. The objective of this study was to examine the relationship between the ability to perceive other unintentional transgressions of social norms and both decision making and emotion recognition as these abilities are critical for appropriate social behavior. METHOD: We examined a group of patients with focal prefrontal cortex damage (N = 28) and a group of matched control participants (N = 28) for their abilities to detect unintentional transgression of social norms using the "Faux-Pas" task of theory of mind, to make advantageous decisions on the Iowa gambling task, and to recognize basic emotions on the Ekman facial affect test. RESULTS: The group of patients with frontal lobe damage was impaired in all of these tasks compared with control participants. Moreover, all the "Faux-Pas", Iowa gambling, and emotion recognition tasks were significantly associated and predicted by executive measures of inhibition, flexibility, or planning. However, only measures from the Iowa gambling task were associated and predicted performance on the "Faux-Pas" task. These tasks were not associated with performance in recognition of basic emotions. These findings suggest that theory of mind, executive functions, and decision-making abilities act in an interdependent way for appropriate social behavior. However, theory of mind and emotion recognition seem to have distinct but additive effects upon social behavior. Results from VLSM analysis also corroborate these data by showing a partially overlapped prefrontal circuitry underlying these cognitive domains.

A Voxel-based lesion study on facial emotion recognition after circumscribed prefrontal cortex damage.

Previous studies have shown inconsistent findings regarding the contribution of the different prefrontal regions in emotion recognition. Moreover, the hemispheric lateralization hypothesis posits that the right hemisphere is dominant for processing all emotions regardless of affective valence, whereas the valence specificity hypothesis posits that the left hemisphere is specialized for processing positive emotions while the right hemisphere is specialized for negative emotions. However, recent findings suggest that the evidence for such lateralization has been less consistent. In this study, we investigated emotion recognition of fear, surprise, happiness, sadness, disgust, and anger in 30 patients with focal prefrontal cortex lesions and 30 control subjects. We also examined the impact of lesion laterality on recognition of the six basic emotions. The results showed that compared to control subjects, the frontal subgroups were impaired in recognition of three negative basic emotions of fear, sadness, and anger - regardless of the lesion laterality. Therefore, our findings did not establish that each hemisphere is specialized for processing specific emotions. Moreover, the voxel-based lesion symptom mapping analysis showed that recognition of fear, sadness, and anger draws on a partially common bilaterally distributed prefrontal network.

Relationships between executive function, working memory, and decision-making on the Iowa Gambling Task: Evidence from ventromedial patients, dorsolateral patients, and normal subjects.

The results of previous studies are inconsistent in regard to the relationship between the Iowa Gambling Task (IGT), working-memory (WM), and executive tasks, and whether these cognitive processes could be considered as mechanisms underlying a decision-making deficit. Moreover, the relationship between the IGT and executive measures is examined based on a limited number of executive tasks, within different populations showing diffuse damage. In addition, there are fewer studies carried out within control participants, with those studies also being inconclusive. It is also suggested that the association of the IGT performance with executive tasks depends on whether the IGT was running under ambiguity or under risk. In this work, all of these issues are studied. Results showed that both patients with ventromedial (VMPFC, N = 10) and dorsolateral (DLPFC, N = 10) prefrontal cortex lesions are significantly impaired on almost all executive tasks, WM tasks, and the IGT. Furthermore, when the IGT is run under risk, there are significant correlations between executive measures and the IGT for the DLPFC patients and the control participants (N = 34) but not the VMPFC patients. No correlation was found between WM tasks and the IGT for both frontal subgroups and control participants. These findings suggested that the mechanisms underlying the IGT deficit differ according to the lesion locations.