How pain empathy depends on ingroup/outgroup decisions: A functional magnet resonance imaging study.

Showing empathy is crucial for social functioning and empathy is related to group membership. The aim of the current study was to investigate the influence of experimentally generated groups on empathy for pain in a functional magnetic resonance imaging (fMRI) paradigm. Thirty healthy participants underwent a minimal group paradigm to create two groups. While BOLD contrast was measured using fMRI, subjects were instructed to empathize with ingroup and outgroup members, who were depicted in a picture paradigm of painful and neutral situations. Behavioral measure of state empathy was measured using a visual analog scale. Furthermore, self-reported trait empathy measures were obtained. Repeated-measures ANOVAs were conducted for fMRI and behavioral data. In addition to a main effect of pain in pain-related areas, a main effect of group in areas belonging to the visual cortex was found. Although there was no ingroup bias for empathy ratings, subjects showed altered neural activation in regions of the right fusiform gyrus, the cerebellum, the hippocampal and amygdala region during the pain×group interaction. Activation in the preceding structures, revealed by the interaction of pain by group, suggests that activation in the pallidum might reflect specific empathy for pain-related regulation processes.

Comparing the neural correlates of affective and cognitive theory of mind using fMRI: Involvement of the basal ganglia in affective theory of mind.

Theory of Mind (ToM) is the ability to infer other people's mental states like intentions or desires. ToM can be differentiated into affective (i.e., recognizing the feelings of another person) and cognitive (i.e., inferring the mental state of the counterpart) subcomponents. Recently, subcortical structures such as the basal ganglia (BG) have also been ascribed to the multifaceted concept ToM and most BG disorders have been reported to elicit ToM deficits. In order to assess both the correlates of affective and cognitive ToM as well as involvement of the basal ganglia, 30 healthy participants underwent event-related fMRI scanning, neuropsychological testing, and filled in questionnaires concerning different aspects of ToM and empathy. Directly contrasting affective (aff) as well as cognitive (cog) ToM to the control (phy) condition, activation was found in classical ToM regions, namely parts of the temporal lobe including the superior temporal sulcus, the supplementary motor area, and parietal structures in the right hemisphere. The contrast aff > phy yielded additional activation in the orbitofrontal cortex on the right and the cingulate cortex, the precentral and inferior frontal gyrus and the cerebellum on the left. The right BG were recruited in this contrast as well. The direct contrast aff > cog showed activation in the temporoparietal junction and the cingulate cortex on the right as well as in the left supplementary motor area. The reverse contrast cog > aff however did not yield any significant clusters. In summary, affective and cognitive ToM partly share neural correlates but can also be differentiated anatomically. Furthermore, the BG are involved in affective ToM and thus their contribution is discussed as possibly providing a motor component of simulation processes, particularly in affective ToM.

Patients with idiopathic rapid-eye-movement sleep behavior disorder show normal gastric motility assessed by the 13C-octanoate breath test.

BACKGROUND: Delayed gastric emptying is a non-motor symptom of Parkinson's disease. Few data exist on gastric emptying in early-stage Parkinson's disease. In idiopathic rapid-eye-movement sleep behavior disorder, a presumable pre-motor stage of Parkinson's disease, gastric emptying has not yet been investigated. METHODS: Twenty healthy controls, 13 patients with idiopathic rapid-eye-movement sleep behavior disorder, and 39 patients with Parkinson's disease patients underwent standardized testing for gastric emptying with the (13)C-octanoate breath test. RESULTS: Gastric emptying was significantly delayed in drug-naïve (P < .001) and in treated Parkinson's disease patients (P < .001), but normal in patients with idiopathic rapid-eye-movement sleep behavior disorder. CONCLUSIONS: Our study confirms delayed gastric emptying in drug-naïve, early-stage Parkinson's disease. Normal gastric emptying in idiopathic rapid-eye-movement sleep behavior disorder might be explained by the fact that neurodegenerative changes in structures modulating gastric motility are not severe enough to cause a functional deficit that can be detected by the (13)C-octanoate breath test.

Parkinson's disease and dementia: a longitudinal study (DEMPARK).

BACKGROUND: Parkinson's disease (PD) is a progressive neurodegenerative motor disorder. However, non-motor complications frequently alter the course of the disease. A particularly disabling non-motor symptom is dementia. METHODS/DESIGN: The study is designed as a multicentre prospective, observational cohort study of about 700 PD patients aged 45-80 years with or without dementia and PD-mild cognitive impairment (MCI). The patients will be recruited in eight specialized movement disorder clinics and will be followed for 36 months. Information about the patients' functional status will be assessed at baseline and 6-/12- month intervals. In addition, 120 patients with dementia with Lewy bodies (DLB) will be included. Well-established standardized questionnaires/tests will be applied for detailed neuropsychological assessment. In addition, patients will be asked to participate in modules including volumetric MRI, genetic parameters, and neuropsychology to detect risk factors, early diagnostic biomarkers and predictors for dementia in PD. RESULTS: The study included 604 PD patients by March 2011; 56.3% were classified as having PD alone, with 30.6% of patients suffering from PD-MCI and 13.1% from PD with dementia. The mean age of the cohort was 68.6 ± 7.9 years, with a mean disease duration of 6.8 ± 5.4 years. There was a preponderance of patients in the earlier Hoehn and Yahr stages. CONCLUSION: The main aim of the study is to characterize the natural progression of cognitive impairment in PD and to identify factors which contribute to the evolution and/or progression of the cognitive impairment. To accomplish this aim we established a large cohort of PD patients without cognitive dysfunction, PD patients with MCI, and PD patients with dementia, to characterize these patients in a standardized manner, using imaging (serial structural MRI), genetic and proteomic methods in order to improve our understanding of the course of the PD process and the development of cognitive dysfunction and dementia in this disease. The inclusion of the DLB patients will start in the second quarter of 2011 in the BMBF-funded follow-up project LANDSCAPE.

Postprandial ghrelin response is reduced in patients with Parkinson's disease and idiopathic REM sleep behaviour disorder: a peripheral biomarker for early Parkinson's disease?

Ghrelin, an orexigenic peptide, has multiple functions, which include promoting gastrointestinal motility and influencing higher brain functions. Experimental data suggest that ghrelin has neuroprotective potential in the MPTP mouse model of Parkinson's disease (PD). PD patients show delayed gastric emptying and other symptoms that may relate to disturbed excretion of ghrelin. No data are available on postprandial ghrelin response in patients with PD and idiopathic REM sleep behaviour disorder (iRBD)--a condition considered a putative preclinical stage of PD. We measured fasting and postprandial ghrelin serum concentrations in 20 healthy controls, 39 (including 19 drug-naïve) PD patients and 11 iRBD patients using a commercial radioimmunoassay for total ghrelin. For statistical analysis we employed ANCOVA and post-hoc testing with Bonferroni's method. Controls showed a decrease of mean fasting ghrelin serum concentrations in the early postprandial phase, followed by a recuperation starting 60 min after the test meal and reaching a maximum at 300 min. This recuperation was less pronounced in PD and iRBD; the slope of relative postprandial ghrelin recovery was different between the investigated groups (p = 0.007). Post-hoc testing showed a difference between controls and PD patients (p = 0.002) and between controls and iRBD patients (p = 0.037). The dynamic regulation of ghrelin in response to food intake is partially impaired in subjects at putative preclinical (iRBD) and clinical stages of PD. Reduced ghrelin excretion might increase the vulnerability of nigrostriatal dopaminergic neurons as suggested by animal studies. The impaired ghrelin excretion might qualify as a peripheral biomarker and be of diagnostic or therapeutic value.

Affective and cognitive Theory of Mind in patients with parkinson's disease.

Theory of Mind (ToM), which is the ability to infer other people's mental states such as beliefs or desires, is an important prerequisite for social interaction. Affective and cognitive subcomponents of ToM can be impaired selectively in neurological and psychiatric disorders. This study examines ToM in 21 Parkinson's disease (PD) patients and 21 healthy control (HC) subjects, using the computerized "Yoni task" that assesses affective and cognitive ToM abilities and an extensive battery of neuropsychological tests. Furthermore, questionnaires to assess health-related quality of life and depressive symptoms were applied and correlations to ToM were investigated. Compared to the control subjects, PD patients scored lower on both the affective (PD: 76% versus HC: 89%; p = 0.006) and cognitive (PD: 80% versus HC: 92%; p = 0.002) ToM subscales but not on control items (PD: 90% versus HC: 95%; p = 0.077). The ToM abilities were not associated with other cognitive functions, depressive symptoms or clinical data. However, affective ToM was correlated with health-related quality of life (p = 0.01). Parkinson patients are impaired in affective as well as cognitive ToM. These deficits are largely independent from other cognitive impairments, depressive symptoms and motor impairment. The relationship of affective ToM to the health-related quality of life of PD patients points to a clinical relevance of this issue and suggests that ToM dysfunctions must be regarded as an important non-motor feature of Parkinson's disease.

The rewarding nature of social interactions.

The objective of this short review is to highlight rewarding aspects of social interactions for humans and discuss their neural basis. Thereby we report recent research findings to illustrate how social stimuli in general are processed in the reward system and highlight the role of Theory of Mind as one mediating process for experiencing social reward during social interactions. In conclusion we discuss clinical implications for psychiatry and psychotherapy.

Theory of mind in Parkinson's disease and related basal ganglia disorders: a systematic review.

Theory of mind (ToM), defined as the ability to infer other people's mental states, is a crucial prerequisite of human social interaction and a major topic of interest in the recent neuroscientific research. It has been proposed that ToM is mediated by a complex neuroanatomical network that includes the medial prefrontal cortex, the anterior gyrus cinguli, the sulcus temporalis superior, the temporal poles, and the amygdala. Various neurological and psychiatric diseases are accompanied by aspects of dysfunctional ToM processing. In this review, the association between basal ganglia, involved in the organization of complex cognitive and emotional behavior, and ToM processing is discussed. The purpose of this review is to provide an overview of research on ToM abilities in basal ganglia disorders, especially Parkinson's Disease and related disorders.