Cerebellar Volume and Disease Staging in Parkinson's Disease: An ENIGMA-PD Study.

BACKGROUND: Increasing evidence points to a pathophysiological role for the cerebellum in Parkinson's disease (PD). However, regional cerebellar changes associated with motor and non-motor functioning remain to be elucidated. OBJECTIVE: To quantify cross-sectional regional cerebellar lobule volumes using three dimensional T1-weighted anatomical brain magnetic resonance imaging from the global ENIGMA-PD working group. METHODS: Cerebellar parcellation was performed using a deep learning-based approach from 2487 people with PD and 1212 age and sex-matched controls across 22 sites. Linear mixed effects models compared total and regional cerebellar volume in people with PD at each Hoehn and Yahr (HY) disease stage, to an age- and sex- matched control group. Associations with motor symptom severity and Montreal Cognitive Assessment scores were investigated. RESULTS: Overall, people with PD had a regionally smaller posterior lobe (dmax = -0.15). HY stage-specific analyses revealed a larger anterior lobule V bilaterally (dmax = 0.28) in people with PD in HY stage 1 compared to controls. In contrast, smaller bilateral lobule VII volume in the posterior lobe was observed in HY stages 3, 4, and 5 (dmax = -0.76), which was incrementally lower with higher disease stage. Within PD, cognitively impaired individuals had lower total cerebellar volume compared to cognitively normal individuals (d = -0.17). CONCLUSIONS: We provide evidence of a dissociation between anterior "motor" lobe and posterior "non-motor" lobe cerebellar regions in PD. Whereas less severe stages of the disease are associated with larger motor lobe regions, more severe stages of the disease are marked by smaller non-motor regions. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

The ENIGMA Stroke Recovery Working Group: Big data neuroimaging to study brain-behavior relationships after stroke.

The goal of the Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) Stroke Recovery working group is to understand brain and behavior relationships using well-powered meta- and mega-analytic approaches. ENIGMA Stroke Recovery has data from over 2,100 stroke patients collected across 39 research studies and 10 countries around the world, comprising the largest multisite retrospective stroke data collaboration to date. This article outlines the efforts taken by the ENIGMA Stroke Recovery working group to develop neuroinformatics protocols and methods to manage multisite stroke brain magnetic resonance imaging, behavioral and demographics data. Specifically, the processes for scalable data intake and preprocessing, multisite data harmonization, and large-scale stroke lesion analysis are described, and challenges unique to this type of big data collaboration in stroke research are discussed. Finally, future directions and limitations, as well as recommendations for improved data harmonization through prospective data collection and data management, are provided.

Targeting NAAA counters dopamine neuron loss and symptom progression in mouse models of parkinsonism.

The lysosomal cysteine hydrolase N-acylethanolamine acid amidase (NAAA) deactivates palmitoylethanolamide (PEA), a lipid-derived PPAR-α agonist that is critically involved in the control of pain and inflammation. In this study, we asked whether NAAA-regulated PEA signaling might contribute to dopamine neuron degeneration and parkinsonism induced by the mitochondrial neurotoxins, 6-hydroxydopamine (6-OHDA) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). In vitro experiments showed that 6-OHDA and MPTP enhanced NAAA expression and lowered PEA content in human SH-SY5Y cells. A similar effect was observed in mouse midbrain dopamine neurons following intra-striatal 6-OHDA injection. Importantly, deletion of the Naaa gene or pharmacological inhibition of NAAA activity substantially attenuated both dopamine neuron death and parkinsonian symptoms in mice treated with 6-OHDA or MPTP. Moreover, NAAA expression was elevated in postmortem brain cortex and premortem blood-derived exosomes from persons with Parkinson's disease compared to age-matched controls. The results identify NAAA-regulated PEA signaling as a molecular control point for dopaminergic neuron survival and a potential target for neuroprotective intervention.

International Multicenter Analysis of Brain Structure Across Clinical Stages of Parkinson's Disease.

BACKGROUND: Brain structure abnormalities throughout the course of Parkinson's disease have yet to be fully elucidated. OBJECTIVE: Using a multicenter approach and harmonized analysis methods, we aimed to shed light on Parkinson's disease stage-specific profiles of pathology, as suggested by in vivo neuroimaging. METHODS: Individual brain MRI and clinical data from 2357 Parkinson's disease patients and 1182 healthy controls were collected from 19 sources. We analyzed regional cortical thickness, cortical surface area, and subcortical volume using mixed-effects models. Patients grouped according to Hoehn and Yahr stage were compared with age- and sex-matched controls. Within the patient sample, we investigated associations with Montreal Cognitive Assessment score. RESULTS: Overall, patients showed a thinner cortex in 38 of 68 regions compared with controls (dmax  = -0.20, dmin  = -0.09). The bilateral putamen (dleft  = -0.14, dright  = -0.14) and left amygdala (d = -0.13) were smaller in patients, whereas the left thalamus was larger (d = 0.13). Analysis of staging demonstrated an initial presentation of thinner occipital, parietal, and temporal cortices, extending toward rostrally located cortical regions with increased disease severity. From stage 2 and onward, the bilateral putamen and amygdala were consistently smaller with larger differences denoting each increment. Poorer cognition was associated with widespread cortical thinning and lower volumes of core limbic structures. CONCLUSIONS: Our findings offer robust and novel imaging signatures that are generally incremental across but in certain regions specific to disease stages. Our findings highlight the importance of adequately powered multicenter collaborations. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Safinamide improves executive functions in fluctuating Parkinson's disease patients: an exploratory study.

Safinamide is a monoamine-oxidase-B inhibitor with peculiar features. At the dose of 100 mg/day, safinamide stimulates dopaminergic transmission and reduces glutamatergic transmission. Here, we investigated the effects of safinamide 100 mg on executive functions at the end of levodopa dose in fluctuating Parkinson's disease (PD) patients. Thirty-two fluctuating PD patients were submitted at baseline (V1) to the UPDRS-III, the Frontal Assessment Battery (FAB) and the Stroop-Word-Color-Test (SWCT) at the end of levodopa dose. Safinamide was then added to the original therapy. After 12 weeks of treatment, patients underwent the final visit (V2), including the UPDRS-III, the FAB and the SWCT with the same daily time schedule as V1. Treatment with safinamide was associated with significant increases of the total FAB score, SWCT-interference time score and UPDRS-III score. Within FAB subdomains, add-on with safinamide significantly increased motor programming and increased mental flexibility and inhibitory control scores. The results of this exploratory study show that add-on with safinamide improves executive functions at the end of levodopa dose in fluctuating PD patients. In particular, attention and inhibition of cognitive interference were significantly ameliorated by add-on with safinamide, suggesting increased modulatory performances of prefrontal cortical pathways. If confirmed by future research on larger cohorts and under controlled conditions, the present results may represent the basis for a novel indication for the use of safinamide in fluctuating PD patients.

Foot Pressure Wearable Sensors for Freezing of Gait Detection in Parkinson's Disease.

Freezing of Gait (FoG) is a common symptom in Parkinson's Disease (PD) occurring with significant variability and severity and is associated with increased risk of falls. FoG detection in everyday life is not trivial, particularly in patients manifesting the symptom only in specific conditions. Various wearable devices have been proposed to detect PD symptoms, primarily based on inertial sensors. We here report the results of the validation of a novel system based on a pair of pressure insoles equipped with a 3D accelerometer to detect FoG episodes. Twenty PD patients attended a motor assessment protocol organized into eight multiple video recorded sessions, both in clinical and ecological settings and both in the ON and OFF state. We compared the FoG episodes detected using the processed data gathered from the insoles with those tagged by a clinician on video recordings. The algorithm correctly detected 90% of the episodes. The false positive rate was 6% and the false negative rate 4%. The algorithm reliably detects freezing of gait in clinical settings while performing ecological tasks. This result is promising for freezing of gait detection in everyday life via wearable instrumented insoles that can be integrated into a more complex system for comprehensive motor symptom monitoring in PD.

Gender specific decrease of a set of circulating N-acylphosphatidyl ethanolamines (NAPEs) in the plasma of Parkinson's disease patients.

INTRODUCTION: Current markers of Parkinson's disease (PD) fail to detect the early progression of disease state. Conversely, current omics techniques allow the investigation of hundreds of molecules potentially altered by disease conditions. Based on evidence previously collected by our group in a mouse model of PD, we speculated that a particular set of circulating lipids might be significantly altered by the pathology. OBJECTIVES: The aim of current study was to evaluate the potential of a particular set of N-acyl-phosphatidylethanolamines (NAPEs) as potential non-invasive plasma markers of ongoing neurodegeneration from Parkinson's disease in human subjects. METHODS: A panel of seven NAPEs were quantified by LC-MS/MS in the plasma of 587 individuals (healthy controls, n = 319; Parkinson's disease, n = 268); Random Forest classification and statistical modeling was applied to compare Parkinson's disease versus controls. All p-values obtained in different tests were corrected for multiplicity by controlling the false discovery rate (FDR). RESULTS: The results indicate that this panel of NAPEs is able to distinguish female PD patients from the corresponding healthy controls. Further to this, the observed downregulation of these NAPEs is in line with the results in plasma of a mouse model of Parkinson's (6-OHDA). CONCLUSIONS: In the current study we have shown the downregulation of NAPEs in plasma of PD patients and we thus speculate that these lipids might serve as candidate biomarkers for PD. We also suggest a molecular mechanism, explaining our findings, which involves gut microbiota.

Neuropsychiatric symptoms differently affect mild cognitive impairment and Alzheimer's disease patients: a retrospective observational study.

Alzheimer's disease (AD) is the most common form of dementia characterized by the prevalent memory impairment. Mild cognitive impairment (MCI) may represent the early stage of AD, in particular when MCI patients show biomarkers consistent with AD pathology (MCI due to AD). Neuropsychiatric symptoms (NPS) frequently affect both MCI and AD patients. Cerebrospinal-fluid (CSF) tau and ß-amyloid42 (Aß42) levels are actually considered the most sensitive and specific biomarkers for AD neurodegeneration. In the present retrospective observational study, we evaluated CSF biomarkers and neuropsychological data (also including NPS measured by the neuropsychiatric inventory-NPI) in a population of patients affected by MCI due to AD compared with mild to moderate AD patients. We documented higher NPI scores in MCI compared with AD patients. In particular, sub-items related to sleep, appetite, irritability, depression, and anxiety were higher in MCI than AD. We also found the significant correlation between NPS and CSF AD biomarkers in the whole population of MCI and AD patients. Consistently, t-tau/Aß42 ratio correlated with NPS in all the MCI and AD patients. These results suggest the more prevalent occurrence of NPS in MCI patients showing AD pathology and converting to dementia than AD patients. Moreover, a more significant degree of AD neurodegeneration, featured by high t-tau/Aß42 ratio, correlated with more severe NPS, thus supposing that in MCI and AD patients a more extensive AD neurodegeneration is related to more severe behavioral disturbances.

Rasagiline for dysexecutive symptoms during wearing-off in Parkinson's disease: a pilot study.

Wearing-off refers to the predictable worsening of motor and sometimes non-motor symptoms of Parkinson's disease occurring at the end of levodopa dose that improves with the next drug dose. Here, we investigated the efficacy of rasagiline on executive functions at the end of levodopa dose in patients displaying symptoms of wearing-off. Rasagiline was well-tolerated and produced a significant improvement at the Frontal Assessment Battery, together with improvement of motor symptoms at the end of levodopa dose. These results suggest that treatment of motor symptoms of wearing-off with rasagiline may be accompanied by improvement of executive functions, and further support the need for optimizing dopamine replacement therapy in fluctuating Parkinson's disease patients.

Orthostatic hypotension acutely impairs executive functions in Parkinson's disease.

Orthostatic hypotension is a frequent non-motor symptom of Parkinson's disease, with negative prognostic role on cognitive functions. Here we measured the acute effects of orthostatic hypotension on executive functions in Parkinson's disease patients devoid of hypertension, carotid artery stenosis, and significant chronic cerebrovascular pathology. Measurements were carried out during regular visits in outpatient setting. Twenty-eight Parkinson's disease patients were recruited and studied along scheduled outpatient visits. They were divided into two groups (n = 14 each) based on the presence or lack of orthostatic hypotension. This was diagnosed according to international guidelines. All patients were submitted to the Stroop's test and to the phonological and semantic verbal fluency test after 10-min resting in supine position and immediately upon standing in upright position. Testing lasted less than 5 min in either position. In upright position, subjects with orthostatic hypotension displayed significantly worse performances at the Stroop's test word reading time (22.1 ± 4.1 vs. 14.9 ± 4.0 s), interference time (56.1 ± 12.3 vs. 41.4 ± 11.8 s), and number of errors at the interference section (5.8 ± 3.2 vs. 1.3 ± 2.1) as compared to those without orthostatic hypotension. These results demonstrate that worsening of attentive function upon standing can be measured in Parkinson's disease patients with orthostatic hypotension during routine outpatient visits. These findings suggest that clinically asymptomatic orthostatic hypotension in Parkinson's disease patients may acutely worsen neuropsychological performances with possible negative impact on daily functioning.

Dopaminergic system and dream recall: An MRI study in Parkinson's disease patients.

We investigated the role of the dopamine system [i.e., subcortical-medial prefrontal cortex (mPFC) network] in dreaming, by studying patients with Parkinson's Disease (PD) as a model of altered dopaminergic transmission. Subcortical volumes and cortical thickness were extracted by 3T-MR images of 27 PD patients and 27 age-matched controls, who were asked to fill out a dream diary upon morning awakening for one week. PD patients do not substantially differ from healthy controls with respect to the sleep, dream, and neuroanatomical measures. Multivariate correlational analyses in PD patients show that dopamine agonist dosage is associated to qualitatively impoverished dreams, as expressed by lower bizarreness and lower emotional load values. Visual vividness (VV) of their dream reports positively correlates with volumes of both the amygdalae and with thickness of the left mPFC. Emotional load also positively correlates with hippocampal volume. Beside the replication of our previous finding on the role of subcortical nuclei in dreaming experience of healthy subjects, this represents the first evidence of a specific role of the amygdala-mPFC dopaminergic network system in dream recall. The association in PD patients between higher dopamine agonist dosages and impoverished dream reports, however, and the significant correlations between VV and mesolimbic regions, however, provide an empirical support to the hypothesis that a dopamine network plays a key role in dream generation. The causal relation is however precluded by the intrinsic limitation of assuming the dopamine agonist dosage as a measure of the hypodopaminergic state in PD. Periodicals, Inc.

Increased expression of interleukin-18 receptor in blood cells of subjects with mild cognitive impairment and Alzheimer's disease.

Inflammation has been proposed as a leading force in neurodegeneration and Interleukin (IL)-18 is a pro-inflammatory cytokine which is suggested to be implicated in Alzheimer's disease (AD). However, the meaning of the IL-18 participation in this disease is still unclear. Since IL-18 activity is mediated by its heterodimeric receptor complex IL-18Rα/ß, we evaluated the presence of both IL-18R chains on peripheral blood cells of AD patients, as well as in individuals with Mild Cognitive Impairment (MCI), at increased risk to develop AD. More specifically, we compared the levels of CD14(+) monocytes and CD3(+) T-lymphocytes bearing IL-18Rα and ß chains in the two groups of patients with those in healthy control subjects, both before and after in vitro cell treatment with lipopolysaccharide (LPS). While no differences in the levels of monocytes and T-lymphocytes bearing IL-18Rα chain were found among the three groups, either in untreated and LPS-treated conditions, the IL-18Rß chain expression appeared differently regulated in MCI and AD patients, as compared to controls. In particular, the amount of IL-18Rß-bearing monocytes was similar among the three groups at unstimulated conditions, while after LPS treatment it was increased in MCI vs. controls. A significant increase of IL-18Rß-bearing T-lymphocytes was also observed in MCI and AD vs. controls, both in untreated and LPS-stimulated conditions. Our findings indicate that the expression of IL-18R complex on blood cells is perturbed in AD and even more markedly in its preclinical state of MCI, confirming that an increased peripheral activity of IL-18 may be involved in the early phase of AD pathophysiology.

Hedonic tone and its mood and cognitive correlates in Parkinson's disease.

BACKGROUND: Anhedonia has been mainly reported as a symptom of depression and cognitive impairment in Parkinson's disease (PD) patients. Here, we investigated whether hedonic tone depends on depression and clarified its relationship with the cognitive performance of PD patients with different mood disorders. METHODS: In 254 patients, we assessed hedonic tone using the Snaith-Hamilton Pleasure Scale, depression severity using the Beck Depression Inventory, and cognitive performances using the Mental Deterioration Battery. A structural psychiatric interview was used to diagnose major depressive disorder (MDD) and minor depressive disorder (MIND), according to the DSM-IV-TR criteria. RESULTS: PD patients with diagnosis of MDD were more anhedonic than those with MIND and those without depressive disorders. Reduced hedonic tone correlated with depression severity in patients with MDD and no depressive disorders. In multivariate models that consider depression severity and cognitive performances together, anhedonia was related to increased depression severity and episodic memory (auditory-verbal learning) impairment, in patients with MDD and with increased depression severity and attention impairment in patients with no depressive disorders. In patients with MIND, anhedonia did not correlate with depression severity or any cognitive performance score. DISCUSSION: Our findings suggest that anhedonia is related to depression severity and specific cognitive performances in patients with MDD and with no depressive disorder. By contrast, the reduced hedonic tone in patients with MIND is independent from depression severity and cognition. Thus, anhedonia in PD is a heterogeneous and multidimensional phenomenon and require investigation at different levels.

Rotigotine for anxiety during wearing-off in Parkinson's disease with dementia.

BACKGROUND: Wearing-off (WO) refers to the exacerbation of motor and/or non-motor symptoms of Parkinson's disease at the end of dose of dopaminergic medications. Treatment of WO is based on modifying drug schedule, meal timetable and/or increasing dopamine replacement therapy. In advanced and/or demented patients, management of WO is often limited by scarce compliance and by cognitive, psychiatric and dysautonomic side-effects that may accompany increased dopaminergic stimulation. METHODS: Here, we report 2 patients suffering from Parkinson's disease with dementia, who experienced anxiety as non-motor symptom of WO under stable levodopa therapy. In both cases, transdermal rotigotine (4 mg/day) was added to the original dopaminergic therapy. RESULTS: Rotigotine proved beneficial on symptoms of anxiety in both patients, without worsening cognitive and behavioral symptoms. During the 9-month follow-up period, there was a slight improvement of motor impairment, with no worsening of drug-related dyskinesia. CONCLUSIONS: These preliminary results suggest that rotigotine at low dose might improve non-motor symptoms of WO in elderly patients suffering from Parkinson's disease with dementia, without raising major safety issues.

The Italian Validation of the Beck Cognitive Insight Scale: Underlying Factor Structure in Psychotic Patients and the General Population.

Cognitive insight refers to the ability to question one's judgments and cognitive biases and is underpinned by specific metacognitive processes. The Beck Cognitive Insight Scale was developed to assess cognitive insight and includes two subscales, Self-Reflectiveness and Self-Certainty (SC). The present study aimed to investigate the underlying factor structure of the Italian version of the BCIS in patients with schizophrenia (SZ) and in the general population (GP) for the first time. A cross-sectional design was adopted and a GP sample of 624 subjects and an SZ sample of 130 patients were enrolled. In the SZ group, a two-factor solution was supported. The internal reliability of each factor was satisfactory. Two items were eliminated and one item moved from the SC to the SR subscale. In the GP group, a two-factor solution was highlighted. The internal reliability of each factor was satisfactory. However, four items of the SR subscale were deleted. The Italian-validated version of the BCIS shows different structures for the SZ and the GP and is characterized by different features concerning previous studies. This evidence suggests new interpretations of metacognitive processes in the two populations and implies specific therapeutic approaches.

Narrative discourse production in Parkinson's disease: Decoupling the role of cognitive-linguistic and motor speech changes.

Introduction: the interplay between neuropsychological and communicative abilities in Parkinson's disease (PD) has been relatively overlooked, and it is not entirely understood which difficulties are consequent to impaired motor control, and which have a linguistic/cognitive basis. Here, we examined narrative discourse in PD using a multi-level analysis procedure considering sentence-level (productivity, lexical-grammatical processing) and discourse-level processes (narrative organization, informativeness), and partialling out patients' motor speech impairments. The interaction between cognitive (i.e. linguistic and executive) and communication abilities was also investigated. Methods: Twenty-nine PD subjects in the mild stage of the disease were compared to 29 matched healthy comparators (HC) on quantitative measures of narrative discourse derived from two picture description tasks. Multivariate (considering articulation rate and educational attainment as covariates) and univariate (with group membership as independent variable) analyses of variance were conducted on separate linguistic domains. The contribution of executive/linguistic abilities to PD's narrative performance was explored by multiple regression analyses on narrative measures significantly differentiating patients from HC. Results: significant reductions in patients were observed on measures of productivity (less well-formed words, shorter sentences) and informativeness (fewer conceptual units, less informative elements, lower number of details) and these alterations were explained by variations in linguistic abilities (action and object naming) rather than executive abilities. Articulation rate and educational attainment did not impact the observed reduced productivity and under-informativeness. Conclusion: referential narrative discourse is altered in PD, regardless of motor impairments in speech production. The observed reductions in productivity/informativeness aspects of narratives were related to naming abilities and in particular to verbs processing, consistently with the neurocognitive model of motor language coupling. Since narratives are amenable to recurrent and automated analysis for the identification of linguistic patterns potentially anticipating the development of PD and the onset of cognitive deterioration, discourse abilities should be quantitatively and repeatedly profiled in the disorder.

Alexithymia is a non-motor symptom of Parkinson disease.

OBJECTIVES: : To investigate whether alexithymia is linked to the disease process or to psychopathology, particularly depression, in Parkinson disease (PD) patients. DESIGN: : Cross-sectional study. SETTING: : Neuropsychiatry outpatient clinic. PARTICIPANTS: : One hundred PD patients and 100 comparison subjects (CS). MEASUREMENTS: : PD patients and CS underwent a clinical and neuropsychiatric evaluation. Alexithymia was assessed with the 20-item Toronto Alexithymia Scale (TAS-20). Severity of depressive symptoms was measured with the Beck Depression Inventory. A structured psychiatric interview was used to diagnose major and minor depression. Logistic regression analyses with 95% confidence intervals (CI) were used to assess the association between alexithymia and PD. RESULTS: : Alexithymia occurred twice as often in PD patients (22%) as in CS (11%) and major depressive disorder occurred twice as often in CS (30%) than in PD (16%). The frequency of minor depression was almost identical (about 40%) in the 2 groups. Alexithymia was also associated with PD independently from depression. Indeed, after adjustment for sociodemographic factors, antidepressant use and depression severity, PD patients had an almost fourfold higher risk of having alexithymia (OR: 3.9, 95% CI: 1.5-10.0) and 24 times increased odds of having high scores on the TAS-20 items assessing difficulty in identifying emotions than CS (OR: 23.7, 95% CI: 10.1-55.6). CONCLUSIONS: : Our findings suggest that alexithymia is a depression-independent phenomenon in PD patients and may be associated with the disease process. Alexithymia is an important nonmotor symptom of PD and should be considered in patient assessment and management.

Neuropsychiatric, neuropsychological, and neuroimaging features in isolated REM sleep behavior disorder: The importance of MCI.

BACKGROUND: Mild cognitive impairment (MCI) is frequently diagnosed in patients with isolated rapid eye movement (REM) sleep behavior disorder (iRBD), although the extent of MCI-associated neuropathology has not yet been quantified. The present study compared the differences in neuropsychiatric, neuropsychological, and neuroimaging markers of neurodegeneration in MCI-iRBD and iRBD patients with normal cognition. METHODS: Sixty-one patients with iRBD were included in the study: 30 patients were included in the MCI subgroup (RBD-MCI) and 31 in the normal cognition subgroup (RBD-NC). Both groups underwent neuropsychiatric and neuropsychological assessments to evaluate psychopathological symptoms and neuropsychological functions. Brain [18F]FDG PET and 123I-FP-CIT-SPECT were performed to evaluate brain glucose metabolism and nigrostriatal dopaminergic function in convenient subgroups of patients, respectively. RESULTS: Neuropsychological measures generally confirmed overall cognitive decline in patients with iRBD-MCI. Immediate long-term verbal memory and visuospatial functions, as well as attentional-executive impairment were evident in the MCI group compared to the NC group. Neuroimaging results indicated reduced brain glucose uptake in the bilateral posterior cingulate cortex and more evident nigrostriatal deafferentation in the RBD-MCI group. There were no differences in psychopathological symptoms between the two groups. CONCLUSIONS: This study confirmed that iRBD patients with MCI had a more impaired cognitive status that those with NC. Moreover, the MCI subgroup presented reduced cerebral glucose consumption in brain areas critical for cognition, and a more severe deafferentation of the nigro-striatal regions, highlighting the importance of identifying iRBD patients with MCI for urgent neuroprotective trials.

Dysbindin C-A-T haplotype is associated with thicker medial orbitofrontal cortex in healthy population.

The dysbindin (dystrobrevin-binding protein 1) gene has been indicated as one of the most important schizophrenia susceptibility genes. Several genetic variations of this gene have been investigated by using an "intermediate phenotype" approach showing a particular detrimental effect on the prefrontal function in schizophrenic patients. However, the nature of dysbindin function within the brains of healthy individuals is poorly understood, in particular as concerns brain anatomy. We examine relationships between a previously implicated three marker C-A-T dysbindin haplotype and regional cortical thickness in a wide population genotyped for risk carriers (n=14) and non-risk carriers (n=93). Surface-based analysis of the cortical mantle showed that the dysbindin haplotype was associated with structural differences in the medial orbitofrontal cortex, where the risk carriers showed the highest cortical thickness values and the non-risk carriers the lowest. Our study extends previous evidence found on schizophrenic patients to the healthy population, demonstrating the influence of dysbindin risk variants on the neuronal architecture of a specific brain region relevant to the neuropathology of schizophrenia.

Amygdala and hippocampus volumetry and diffusivity in relation to dreaming.

Microstructural analyses by MRI brain scans and by DTI analysis of MR images were used to investigate the possible relationship between deep gray matter structures (amygdala and hippocampus) and dreaming in healthy subjects. Thirty-four subjects ranging in age 20s to 70s underwent to a MRI protocol for the assessment of volume and mean diffusivity (MD) in the amygdala and hippocampus and were asked to fill out a dream diary via audiotape recording upon morning awakening for two weeks. Multiple regression analyses evaluated the relationships between anatomical measures and quantitative and qualitative measures of the reported dreams. The main result points to a dissociation between some quantitative and qualitative aspects of dream reports. While the mean number of dreams recalled per day did not show any significant relationship with the neuroanatomical measures, significant associations with some qualitative features of the recalled dreams (emotional load, bizarreness, and vividness) and, to some extent, with the length of dream reports were observed. Particularly, a higher MD of the left amygdala, reflecting a decreased microstructural integrity, was associated with shorter dream reports and lower scores on emotional load. Bizarreness of dream reports was negatively correlated with the left amygdala volume and positively correlated with the right amygdala MD. Some specific, although weaker, relationships were also found between bizarreness and hippocampal measures. These findings indicate some direct relationships between volumetric and ultrastructural measures of the hippocampus-amygdala complex and specific qualitative features of dreaming.