[Left and Right Hemispheric Contribution to Social Cognition].

Can we find hemispheric differences in the neural systems of social cognition? Social cognition is supported by a number of cognitive systems. Emotion plays an important role in understanding others and in controlling self-action. Theory of mind, the ability to infer the mental state of others, consists of subsystems such as empathy, mentalization, and perspective taking. Key brain structures for these cognitive processes are the medial prefrontal cortex, regions around the superior temporal sulcus, and the temporo-parietal junction. Most studies show right hemisphere dominance in emotional and social processes. With regard to the theory of mind, empathy is dominantly supported by the right hemisphere. However, some findings suggest the involvement of both hemispheres in mentalization and perspective talking. Social cognition is a complex process and should be considered as the consequence of inter-hemispheric processing involving several structures, although it is mainly right-hemisphere dominant.

[Voxel-Based Morphometry and Social Cognitive Function in Parkinson's Disease].

In recent years, voxel-based morphometry (VBM) has been increasingly used to investigate local brain structures in Parkinson's disease (PD). Compared to healthy participants, PD patients tend to show reduced brain volume in limbic and paralimbic areas in early disease stages, while the neocortical areas, such as the temporal and frontal cortices, are affected in advanced patients. Moreover, there are many studies showing correlation between cognitive performance and local brain volume. In the last decade, emotional and social cognitive function, such as facial emotion recognition, emotional decision-making, and theory of mind, have been the target of VBM analysis in PD. These studies facilitate understanding of the nature of communication and behavioral disorders that some PD patients display. However, there are discrepancies in VBM results between studies. Future studies need to employ larger sample sizes and combined analysis of brain perfusion or network connectivity in order to confirm brain structural changes and their effects on social cognitive function in PD patients.

Decision-making performance in Parkinson's disease correlates with lateral orbitofrontal volume.

BACKGROUND: Patients with Parkinson's disease (PD) exhibit poor decision-making, and the underlying neural correlates are unclear. We used voxel-based morphometry with Diffeomorphic Anatomical Registration through Exponentiated Lie algebra to examine this issue. METHODS: The decision-making abilities of 20 patients with PD and 37 healthy controls (HCs) were measured with a computerized Iowa Gambling Task (IGT). We assessed the local gray matter volumes of the patients and HCs and their correlations with decision-making performance, disease duration, disease severity, and anti-Parkinsonism medication dose. RESULTS: Compared with the HCs, the patients with PD exhibited poor IGT performances. The gray matter volumes in the medial orbitofrontal cortex, left inferior temporal cortex, and right middle frontal gyrus were decreased in the patients. Results in the regression analysis showed that lateral orbitofrontal volume correlated with performance in the IGT in PD. Regions that correlated with disease duration, severity, and medication dose did not overlap with orbitofrontal regions. CONCLUSION: Our results indicate that the lateral and medial orbitofrontal cortex are related to decision-making in PD patients. Since the medial orbitofrontal cortex is shown to be involved in monitoring reward, reward monitoring seems to be impaired as a whole in PD patients. Meanwhile, the lateral region is related to evaluation of punishment, which is considered to have an influence on individual differences in decision-making performance in PD patients.

[Decision Making and Electrodermal Activity].

Decision making is aided by emotions. Bodily responses, such as sweating, heartbeat, and visceral sensation, are used to monitor the emotional state during decision making. Because decision making in dairy life is complicated and cognitively demanding, these bodily signals are thought to facilitate the decision making process by assigning positive or negative values for each of the behavioral options. The sweat response in a decision making task is measured by skin conductance response (SCR). SCR in decision making is divided into two categories: anticipatory SCR is observed before making decisions, and reward/punishment SCR is observed after the outcome of the decision is perceived. Brain lesion studies in human revealed that the amygdala and ventromedial prefrontal cortex are important in decision making. Patients with lesinon in the amygdala exhibit neither the anticipatory nor reward/punishment SCRs, while patients with the ventromedial prefrontal lesions have deficits only in the anticipatory SCRs. Decision making tasks and SCR analysis have contributed to reveal the implicit aspects of decision making. Further research is necessary for clarifying the role of explicit process of decision making and its relationship with the implicit process.

[Social Cognitive Impairment in Myotonic Dystrophy Type 1].

Myotonic dystrophy type 1 (DM 1) is a heritable, multisystem disease that affects not only the muscles but also the brain. DM 1 is often accompanied by developmental behavioral disorders, such as autism spectrum disorders. The autistic traits in DM 1 may be related to social cognitive dysfunction. The social cognitive function of patients with DM 1 was examined with respect to facial emotion recognition and theory of mind, which is the specific cognitive ability to understand the mental states of other people. With respect to facial emotion recognition, the sensitivities to disgust and anger were lower among patients with DM 1 than among healthy subjects, and this difference could not be attributed to visual impairment. To examine the theory of mind ability, the "Reading the Mind in the Eyes" test and the faux pas recognition test were used. Patients with DM 1 were found to be impaired in both tests, but the results were not attributed to visual ability and lexical comprehension. The possible causes of social cognitive dysfunction in DM 1 are the l cerebral atrophy and white matter abnormalities in the temporal, frontal, and insular cortex. Dysfunctions in these areas may affect the emotional and theory of mind abilities in DM 1, which result in the behavioral and communication disorders.

[Disorders of body schema].

A variety of disorders have been associated with the concept of body schema. However, this concept has been interpreted in many ways, and there is no consensus on the nature and cognitive mechanisms of body schema. Historically, two major issues have been discussed. One was the body-specificity of the body schema, and the other was the relationship between input and output modality. Autotopagnosia, an inability to localize and orient different parts of the body, has been a focus of attention because it is thought to provide insight into the function of body schema. Although there have not been many cases of pure autotopagnosia, a double dissociation indicating the independence of body-specific system. There are a few working hypotheses for cognitive models of body schema, which can explain the different types of autotopagnosia. One model includes multiple representation subsystems for body processing, while another assumes the use of intrinsic and extrinsic egocentric coordinates to maintain on-line processing for body state. The consistency of these accounts should be examined in light of extensive neuroimaging and psychological data, to construct a plausible model for body schema.

[Neurological disease and facial recognition].

To discuss the neurological basis of facial recognition, we present our case reports of impaired recognition and a review of previous literature. First, we present a case of infarction and discuss prosopagnosia, which has had a large impact on face recognition research. From a study of patient symptoms, we assume that prosopagnosia may be caused by unilateral right occipitotemporal lesion and right cerebral dominance of facial recognition. Further, circumscribed lesion and degenerative disease may also cause progressive prosopagnosia. Apperceptive prosopagnosia is observed in patients with posterior cortical atrophy (PCA), pathologically considered as Alzheimer's disease, and associative prosopagnosia in frontotemporal lobar degeneration (FTLD). Second, we discuss face recognition as part of communication. Patients with Parkinson disease show social cognitive impairments, such as difficulty in facial expression recognition and deficits in theory of mind as detected by the reading the mind in the eyes test. Pathological and functional imaging studies indicate that social cognitive impairment in Parkinson disease is possibly related to damages in the amygdalae and surrounding limbic system. The social cognitive deficits can be observed in the early stages of Parkinson disease, and even in the prodromal stage, for example, patients with rapid eye movement (REM) sleep behavior disorder (RBD) show impairment in facial expression recognition. Further, patients with myotonic dystrophy type 1 (DM 1), which is a multisystem disease that mainly affects the muscles, show social cognitive impairment similar to that of Parkinson disease. Our previous study showed that facial expression recognition impairment of DM 1 patients is associated with lesion in the amygdalae and insulae. Our study results indicate that behaviors and personality traits in DM 1 patients, which are revealed by social cognitive impairment, are attributable to dysfunction of the limbic system.

Theory of mind impairment in adult-onset myotonic dystrophy type 1.

Patients with myotonic dystrophy type 1 (DM 1) exhibit behavioral disorders and distinctive personality traits. We hypothesize that this is due to altered social cognitive function. To investigate the cognitive basis of this impairment in DM 1 patients, we examined their theory of mind (ToM) ability, which is the specific cognitive ability to understand the mental states of others. Nine adult-onset DM 1 patients (4 men and 5 women) performed 2 ToM tasks: "Reading the Mind in the Eyes" test and faux pas recognition test. DM 1 patients were found to be impaired in both ToM tests, but had no difficulty with control tasks designed to test visual and lexical comprehension. The present results indicate that social cognitive impairment in patients with adult-onset DM 1 is associated with ToM dysfunction, which could be due to the brain lesions associated with this disease.

Neuropsychological and radiological assessments of two cases with apparent idiopathic rapid eye movement sleep behaviour disorder.

We examined two male patients (64 and 70 years old) with rapid eye movement sleep behaviour disorder (RBD) using cognitive tests, myocardial (123)I-metaiodobenzylguanidine (MIBG) scintigraphy, and dopamine positron emission tomography (PET) imaging. One patient had impaired social cognition and decision-making skills and reduced MIBG reuptake, and dopamine PET imaging indicated striatal terminal loss. The other patient had normal social cognition and reduced MIBG reuptake, but no abnormalities were detected by dopamine PET imaging. Both patients reported constipation. This study supports the hypothesis by Braak et al. [Mov Disord 2006;21:2042-2051] that impairment of the amygdala and striatum occurs at the same stage as α-synucleinopathy, and the findings suggest that autonomic dysfunctions such as reduced MIBG reuptake and constipation are the earliest symptoms of RBD. Detailed neuropsychological and radiological assessments of these 2 cases revealed that idiopathic RBD could develop in various clinical situations and include cognitive and autonomic changes. Further longitudinal studies with larger sample sizes will help understand the neuropsychology and pathophysiology of RBD.

[Neural and cognitive correlates of social cognition: findings on neuropsychological and neuroimaging studies].

Social cognition includes various components of information processing related to communication with other individuals. In this review, we have discussed 3 components of social cognitive function: face recognition, empathy, and decision making. Our social behavior involves recognition based on facial features and also involves empathizing with others; while making decisions, it is important to consider the social consequences of the course of action followed. Face recognition is divided into 2 routes for information processing: a route responsible for overt recognition of the face's identity and a route for emotional and orienting responses based on the face's personal affective significance. Two systems are possibly involved in empathy: a basic emotional contagion "mirroring" system and a more advanced "theory of mind" system that considers the cognitive perspective. Decision making is mediated by a widespread system that includes several cortical and subcortical components. Numerous lesion and neuroimaging studies have contributed to clarifying the neural correlates of social cognitive function, and greater information can be obtained on social cognitive function by combining these 2 approaches.

Impairment of odor recognition and odor-induced emotions in type 1 myotonic dystrophy.

This study aimed to test whether type 1 myotonic dystrophy (DM1) patients who have a lower sensitivity to emotional facial expressions have an abnormal olfactory threshold or recognition level. We measured DM1 patients' performances in an olfactory acuity test and respiratory responses to odor stimuli, and compared their results to those of healthy controls (HCs). We found that DM1 patients exhibited a significantly reduced odor detection sensitivity compared with that in HCs. Three out of seven DM1 patients exhibited impaired odor recognition, while other four patients had significantly lower odor recognition compared with HCs. Even when patients were able to identify the type of odor, the levels of pleasantness they reported experiencing in response to a pleasant odor were significantly lower than those reported by HCs. These subjective data in DM1 patients were reflected in the respiratory responses (RRs). In the current study, one patient showed impairments in both odor detection and odor recognition. Abnormalities of the olfactory limbic areas might have been the cause of the olfactory impairments observed in the DM1 patients.

Is "reading mind in the eyes" impaired in Parkinson's disease?

Theory of mind (ToM) is the specific cognitive ability to understand other people's mental states. Several studies have examined ToM ability in patients with Parkinson's disease (PD), using the "reading mind in the eyes" test (RMET). However, there has been no agreement as to whether or not ToM ability in this task is affected by PD. In order to obtain conclusive evidence regarding ToM ability in PD, we examined RMET-related performance in nondemented PD patients; we also used the semantic discrimination task to exclude the possibility that PD patients had difficulty in distinguishing emotional adjectives. Results indicated that ToM ability in the RMET is impaired in PD patients, and that this finding was not attributable to the visual processing of faces or the verbal comprehension of emotional adjectives. Thus, the affective aspects of ToM can be impaired in PD patients.

Decision-making in temporal lobe epilepsy examined with the Iowa gambling task.

Although memory, language, and executive functions have been extensively studied in patients with mesial temporal lobe epilepsy (MTLE), few investigations of the decision-making abilities of these patients have been performed. We studied implicit decision-making (decisions under ambiguity) in right and left MTLE patients using the Iowa Gambling Task. The Iowa Gambling Task is believed to detect deficits in decision-making caused by either ventromedial prefrontal cortex or amygdalo-hippocampal lesions. In the present study, MTLE patients scored poorly compared to healthy controls on this task, and right MTLE patients exhibited worse performance than left MTLE patients. Our findings indicate that the amygdalo-hippocampal complexes play important roles in decision-making. The right amygdalo-hippocampal complexes may play more important roles in implicit decision-making in particular.

Attention deficits in Japanese multiple sclerosis patients with minor brain lesion loads.

BACKGROUND: To investigate whether Japanese multiple sclerosis (MS) patients with minor brain lesion loads have attention deficits and brain atrophy, and to correlate their circumstance. METHOD: Twenty-one Japanese patients with relapsing-remitting MS were included in this study. Attention deficits were evaluated using Clinical Assessment for Attention (CAT) standardized according to age groups. Lesion load in the brain was assessed by tallying the total volume of plaques visible on brain magnetic resonance imaging (MRI). The width of the third ventricle and the bicaudate ratio were measured. RESULTS: The completion time for the visual cancellation tasks and/or the reaction times for the continuous performance test were prolonged in 14 patients (66.7%). The accuracy of responses was preserved throughout the CAT. Deviation from the normal value was not exaggerated based on the increasing difficulty of the task. The total volume of plaques on brain MRI was small. The width of the third ventricle was significantly increased in patients with MS when compared to controls, but was not correlated with the low performance on the CAT. CONCLUSIONS: Japanese MS patients with minor brain lesion loads frequently had attention deficits characterized by slowness of automatic information processing, but controlled processing that requires working memory demands was spared.

[Assessment scales for Alzheimer's disease].

Comprehensive examination is required to make an accurate and effective diagnosis of dementia associated with Alzheimer disease. Cognitive tests and psychological scales are useful for the objectively evaluation of symptoms that may not be completely revealed by the patient's medical history. The pattern and degree of the cognitive symptoms differ between individuals. The methods for evaluating the cognitive abilities of Alzheimer's patients can be divided into 2 categories. The first consists of cognitive tests that examine a certain aspect of cognitive function. The second consists of behavioral assessments that evaluate overall patient behavior. Cognitive tests specifically assess the domain of cognitive function, but their scope may be too narrow. Memory and visuospatial ability tests are useful and important for assessing Alzheimer patients. Behavioral assessments can evaluate the general condition of the patients, but there is a possibility of observer bias. Since Alzheimer disease has a prolonged course and is characterized by general changes, the concomitant use of cognitive tests and behavioral assessments is important for long-term assessment.

Sensitivity to reward and punishment in Parkinson's disease: an analysis of behavioral patterns using a modified version of the Iowa gambling task.

Studies using the Iowa gambling task (IGT) have shown that patients with Parkinson's disease (PD) make disadvantageous choices characterized by immediate large rewards and delayed larger punishments. These results can be interpreted in two ways: either PD patients are hypersensitive to immediate outcomes and/or insensitive to delayed consequences or PD patients are hypersensitive to rewards and/or insensitive to punishments. In this study, we used a modified IGT in which selection of cards from the disadvantageous decks leads to immediate, small punishments and delayed, smaller rewards and selection of cards from the advantageous decks leads to immediate, large punishments and delayed larger rewards. We then compared the results obtained using this modified IGT with those obtained using the original IGT. If the PD patients were hypersensitive to the immediate outcomes of decisions, they would make disadvantageous choices in both the original and the modified IGTs. Differences between the results of the original and modified tasks would indicate impairments in balancing reward and punishment. In our analysis, PD patients selected advantageous decks and gained as much as normal subjects during the modified IGT, but they selected disadvantageous decks during the original IGT. These results indicate that the decision-making difficulties of PD patients are caused by their inability to balance reward and punishment and their hypersensitivity to reward and/or insensitivity to punishment.

Facial emotion recognition and cerebral white matter lesions in myotonic dystrophy type 1.

In order to investigate the cognitive and neurological bases of social cognitive impairment in myotonic dystrophy type 1 (DM1), we examined the facial expression recognition abilities and the cerebral lesions in a group of DM 1 (5 men, 4 women). We measured sensitivity to facial emotions and compared the findings with magnetic resonance image (MRI) findings evaluated using a semi-quantitative method. The DM1 patients showed lower sensitivity to disgusted and angry faces as compared to the healthy controls. The assessment of brain lesions revealed that more severe lesions occurred in the frontal, temporal, and insular white matters. Sensitivity to the emotion of disgust was negatively correlated with temporal lesions, and sensitivity to anger negatively correlated with frontal, temporal, and insular lesions. The results of this study indicate an association between lesions in the frontal, temporal, and insular subcortices and decreased emotional sensitivity to disgust and anger in DM1 patients. These areas are thought to play an important role in emotional processing in the normal brain. Our results suggest that social cognitive impairment in DM1 patients is attributable to impaired emotional processing linked to white matter lesions.

[New approach to apraxia].

Our collective understanding of our approach to apraxia has not dramatically changed over the last century. The classical approach to apraxia has occasionally caused confusion and disagreements because it lacks established definitions for apraxia and related terms such as "praxicon" or "ideation". Rather, the current system allows each researcher to define these terms differently, making it extremely difficult to compare cases reported by different researchers. New approaches, however, are providing more concrete definitions, enabling us to describe apraxic disorders more operationally, this may help prevent the disagreement concerning these definitions. A more recent approach, demonstrated in several reports, focuses on the interactions between "body" and "objects". Another approach concentrates on information processing such as "online processing" and the retrieval of stored knowledge. These new approaches to apraxia have the potential to improve our ability to communicate about this condition. In future studies, these conceps should be integrated into the classical approach to create a single, workable model for understanding apraxic syndromes.