Huntington\'s disease (HD) is a debilitating neurodegenerative genetic disorder caused by an expanded polyglutamine-coding (CAG) trinucleotide repeat in the huntingtin (HTT) gene. HD behaves as a highly penetrant dominant disorder likely acting through a toxic gain of function by the mutant huntingtin protein. Widespread cellular degeneration of the medium spiny neurons of the caudate nucleus and putamen are responsible for the onset of symptomology that encompasses motor, cognitive, and behavioural abnormalities. Over the past 150 years of HD research since George Huntington published his description, a plethora of pathogenic mechanisms have been proposed with key themes including excitotoxicity, dopaminergic imbalance, mitochondrial dysfunction, metabolic defects, disruption of proteostasis, transcriptional dysregulation, and neuroinflammation. Despite the identification and characterisation of the causative gene and mutation and significant advances in our understanding of the cellular pathology in recent years, a disease-modifying intervention has not yet been clinically approved. This review includes an overview of Huntington\'s disease, from its genetic aetiology to clinical presentation and its pathogenic manifestation. An updated view of molecular mechanisms and the latest therapeutic developments will also be discussed.

Clinically, the recurrent artery of Heubner (RAH) aneurysm is extremely rare, commonly presents with subarachnoid hemorrhage (SAH).
A 73-year-old man with a known moyamoya disease who presented as caudate hemorrhage attributable to an incidental flow aneurysm distal on the right RAH, which was managed conservatively after an unsuccessful endovascular attempt. Unfortunately, the patient died five weeks after  hospital discharge because of re-rupture of the aneurysm. To the best of our knowledge, the RAH aneurysm manifesting as caudate hemorrhage without SAH has not previously been reported.
This case highlights that the RAH aneurysm masquerading as caudate hemorrhage without SAH is exceedingly rare but can be encountered, representing a diagnostic and therapeutic challenge, and should be considered in the differential diagnosis. Moreover, early identifying and then eliminating such vascular anomaly if possible is of importance to prevent fatal hemorrhage.

The incidence and prevalence of Parkinson\'s (PD) are increasing rapidly in developing countries. PD is difficult to diagnose based on clinical assessment. Presently, magnetic resonance imaging (MRI) methods such as R2* and Quantitative Susceptibility Mapping (QSM) were found to be useful in diagnosing the PD based on the iron deposition in different regions of the brain. The objective of this review was to evaluate the efficacy of QSM over R2* in assessment of PD. A comprehensive literature search was made on PubMed-Medline, CINAHL, Science Direct, Scopus, Web of Science, and the Cochrane library databases for original research articles published between 2000 and 2018. Original articles that reported the efficacy of QSM and R2* in assessment of PD were included. A total of 327 studies were identified in the literature search. However, only ten studies were eligible for analysis. Of the ten studies, five studies compared the accuracy of QSM over R2* in measuring the iron deposition in different regions of brain in PD. Our review found that QSM has better accuracy in identifying iron deposition in PD patients compared to R2*. However, there is discrepancy in the results between MRI Imaging methods and Postmortem studies. Additional longitudinal research studies are needed to provide a strong evidence base for the use of MRI imaging methods such as R2*and QSM in accurately measuring iron deposition in different regions of brain and serve as biomarkers in PD.

Chorea-acanthocytosis (ChAc) is a rare autosomal recessive inherited syndrome characterized by hyperkinetic movements, seizures, cognitive impairment, neuropsychiatric symptoms, elevated serum biochemical indicators and acanthocytes detection in peripheral blood smear. Vacuolar protein sorting 13A (VPS13A) gene mutations have been proven to be genetically responsible for the pathogenesis of ChAc. Herein, based on the typical clinical symptoms and neuroimaging features, we present two suspected ChAc cases which are further genetically confirmed by four novel VPS13A gene mutations. Nevertheless, the sharp contrast between the population base and published ChAc reports implies that ChAc is considerably underdiagnosed in China. Therefore, we conclude several suggestive features and propose a diagnostic path of ChAc from a clinical, genetic and neuroimaging perspective, aiming to facilitate the diagnosis and management of ChAc in China.

Sex differences are widespread across vertebrate nervous systems. Such differences are sometimes reflected in the neural substrate via neuroanatomical differences in brain region volume. One brain region that displays sex differences in its associated functions and pathologies is the striatum, including the caudate-putamen (dorsal striatum), nucleus accumbens core and shell (ventral striatum). The extent to which these differences can be attributed to alterations in volume is unclear. We thus tested whether the volumes of the caudate-putamen, nucleus accumbens core, and nucleus accumbens shell differed by region, sex, and hemisphere in adult Sprague-Dawley rats. As a positive control for detecting sex differences in brain region volume, we measured the sexually dimorphic nucleus of the medial preoptic area (SDN-POA). As expected, SDN-POA volume was larger in males than in females. No sex differences were detected in the volumes of the caudate-putamen, nucleus accumbens core or shell. Nucleus accumbens core volume was larger in the right than left hemisphere across males and females. These findings complement previous reports of lateralized nucleus accumbens volume in humans, and suggest that this may possibly be driven via hemispheric differences in nucleus accumbens core volume. In contrast, striatal sex differences seem to be mediated by factors other than striatal region volume. This conclusion is presented within the context of a detailed review of studies addressing sex differences and similarities in striatal neuroanatomy.

OBJECTIVE: The incidence of tick-borne encephalitis (TBE) is increasing in many countries. Magnetic resonance imaging (MRI) in the course of TBE is not regularly performed in children. The aim of our study was evaluating MRI-findings of children and adolescents with TBE.
METHODS: Retrospective evaluation of the charts and MRIs of patients who had been treated for TBE in the four participating hospitals in the last twenty years.
RESULTS: 11 patients (5 male; age at TBE 3 weeks-15 9/12 years; mean 104.9 months) were included. MRI (within the first week after admission) revealed symmetric or asymmetric T2-hyperintensities in both thalami in 7/11 patients with additional bilateral lesions in putamen and/or caudate nucleus in 3 patients, and additional cortical lesions in 2 patients. Our youngest patient presented with T2-hyperintensities affecting the whole left cerebral hemisphere including white and grey matter and both cerebellar hemispheres. One patient had a minimal reversible T2-hyperintensity in the splenium of the corpus callosum (RHSCC). 3/11 patients had a normal MRI. 4/11 patients showed complete neurological recovery (2/4 with a normal MRI, RHSCC patient). 6/11 children survived with significant sequelae: hemiparesis (n = 4); cognitive deficits (n = 4); pharmacoresistant epilepsy (n = 2). One patient died of a malignant brain edema.
CONCLUSIONS: A spectrum of MRI findings can be found in children with TBE, often showing involvement of the subcortical deep grey matter structures. In children presenting with a meningoencephalitis and bilateral thalamic involvement TBE should be included in the differential diagnosis.

The symptoms of obsessive-compulsive disorder (OCD) include intrusive thoughts, compulsive behavior, anxiety, and cognitive inflexibility, which are associated with dysfunction in dorsal and ventral corticostriato-thalamocortical (CSTC) circuits. Psychotherapy involving exposure and response prevention has been established as an effective treatment for the affective symptoms, but the impact on the underlying neural circuits is not clear. This systematic review used the Medline, Embase, and PsychINFO databases to investigate how successful therapy may affect neural substrates of OCD. Sixteen studies measuring neural changes after therapy were included in the review. The studies indicate that dysfunctions in neural function and structure are partly reversible and state-dependent for affective symptoms, which may also apply to cognitive symptoms. This is supported by post-treatment decreases of symptoms and activity in the ventral circuits during symptom provocation, as well as mainly increased activity in dorsal circuits during cognitive processing. These effects appear to be common to both psychotherapy and medication approaches. Although neural findings were not consistent across all studies, these findings indicate that people with OCD may experience functional, symptomatic, and neural recovery after successful treatment.

BACKGROUND: To evaluate the literature pertaining to the use of resting-state functional magnetic resonance imaging (fMRI) in Major Depression (MD).
METHODS: A search for papers published in English was conducted using MedLine, Embase, PsycINFO, OvidSP, and ScienceDirect with the following words: resting state, depression, MRI, affective, and default-mode.
RESULTS: The findings from 16 resting-state fMRI studies on MD are tabulated. Some common findings are discussed in further detail.
CONCLUSIONS: The use of resting-state fMRI in MD research has yielded a number of significant findings that provide the basis for understanding the pathophysiology of depressive symptoms. Of particular note and deserving of further research are the roles of the cortico-limbic mood regulating circuit (MRC) and the interaction between task-positive and task-negative networks in MD. There is increasing interest in the use of resting-state fMRI in the study of psychiatric conditions, and continued improvement in technique and methodology will prove valuable in future research.

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BACKGROUND: (18)F-fluorodopa ((18)F-DOPA) is a functional tracer of presynaptic dopaminergic neuron terminations in the nigrostriatal system. This review is aimed to assess the efficacy of (18)F-DOPA-PET in the diagnosis and evaluation of the progression of Parkinson\'s Disease (PD) and in the differential diagnosis with other Parkinsonism Syndromes.
METHODS: A review was made of the literature by searching six databases and selecting the most relevant articles according to strict inclusion and exclusion criteria. The study data were systematically extracted and included in evidence tables.
RESULTS: Of the 1478 registries recovered through the search of the literature, 48 studies were extracted. Of these, only 13 were included in the systematic review. It was observed in all of them that PD is manifested by a lower striatal uptake of (18)F-DOPA, especially in the putamen with posterior predominance. Prospective studies have shown that there is loss of uptake with disease progression. One article described regional differences in (18)F-DOPA striatal pattern between PD, multisystem atrophy (MSA) and progressive supranuclear palsy (PSP). Cognitive impairment in PD seems to be related with (18)F-DOPA abnormal uptake in some regions of frontal cortex and caudate nucleus.
CONCLUSIONS: (18)F-DOPA-PET seems to be useful for the diagnosis and evaluation of PD progression. However, the evidence is not conclusive regarding its utility in the differential diagnosis with other Parkinsonism Syndromes and in the differentiation between ex novo and advanced PD.