Action-based organization of a cerebellar module specialized for predictive control of multiple body parts.

The role of the cerebellum in predictive motor control and coordination has been thoroughly studied during movements of a single body part. In the real world, however, actions are often more complex. Here, we show that a small area in the rostral anterior interpositus nucleus (rAIN) of the mouse cerebellum is responsible for generating a predictive motor synergy that serves to protect the eye by precisely coordinating muscles of the eyelid, neck, and forelimb. Within the rAIN region, we discovered a new functional category of neurons with unique properties specialized for control of motor synergies. These neurons integrated inhibitory cutaneous inputs from multiple parts of the body, and their activity was correlated with the vigor of the defensive motor synergy on a trial-by-trial basis. We propose that some regions of the cerebellum are organized in poly-somatotopic "action maps" to reduce dimensionality and simplify motor control during ethologically relevant behaviors.

A New Projection From the Deep Cerebellar Nuclei to the Hippocampus via the Ventrolateral and Laterodorsal Thalamus in Mice.

The cerebellar involvement in cognitive functions such as attention, language, working memory, emotion, goal-directed behavior and spatial navigation is constantly growing. However, an exact connectivity map between the hippocampus and cerebellum in mice is still unknown. Here, we conducted a tracing study to identify the sequence of transsynaptic, cerebellar-hippocampal connections in the mouse brain using combinations of Recombinant adeno-associated virus (rAAV) and pseudotyped deletion-mutant rabies (RABV) viruses. Stereotaxic injection of a primarily anterograde rAAV-WGA (wheat germ agglutinin)-Cre tracer virus in the deep cerebellar nuclei (DCN) of a Cre-dependent tdTomato reporter mouse resulted in strong tdTomato labeling in hippocampal CA1 neurons, retrosplenial cortex (RSC), rhinal cortex (RC) as well as thalamic and cerebellar areas. Whereas hippocampal injections with the retrograde tracer virus rAAV-TTC (tetanus toxin C fragment)-eGFP, displayed eGFP positive cells in the rhinal cortex and subiculum. To determine the sequence of mono-transsynaptic connections between the cerebellum and hippocampus, we used the retrograde tracer RABVΔG-eGFP(EnvA). The tracing revealed a direct connection from the dentate gyrus (DG) in the hippocampus to the RSC, RC and subiculum (S), which are monosynaptically connected to thalamic laterodorsal and ventrolateral areas. These thalamic nuclei are directly connected to cerebellar fastigial (FN), interposed (IntP) and lateral (Lat) nuclei, discovering a new projection route from the fastigial to the laterodorsal thalamic nucleus in the mouse brain. Collectively, our findings suggest a new cerebellar-hippocampal connection via the laterodorsal and ventrolateral thalamus to RSC, RC and S. These results strengthen the notion of the cerebellum's involvement in cognitive functions such as spatial navigation via a polysynaptic circuitry.

Brain iron accumulation in a blood donor family with restless legs syndrome. / Aumento de los depositos cerebrales de hierro en una familia de donantes de sangre con sindrome de piernas inquietas.

INTRODUCTION: The pathophysiology of restless legs syndrome (RLS) is complex. Secondary RLS with iron deficiency -which suggests disturbed iron homeostasis- remains to be elucidated. CASE REPORTS: We report the findings from a unique blood donor family with RLS. Three blood donors family members were diagnosed with RLS defined by the International RLS Study Group and without history of neurologic diseases and RLS symptoms in the last 3-5 years (range of blood donation: 10-40 years). The neurological examination and electromyographies were normal. A polisomnography showed disturbed nocturnal sleep with a reduction in sleep efficiency and an increased periodic limbs movement index. The cranial MRI showed brain iron deposits in basal ganglia, substantia nigra, red nuclei and dentate nuclei. Phenotypic and genotypic studies rule out genetic haemochromatosis or iron overload. CONCLUSION: The abnormal iron accumulation in the basal ganglia indicated a complex iron metabolism disorder of the central nervous system. Further studies are warranted to confirm our findings and its role in the pathophysiology of RLS.

TITLE: Aumento de los depositos cerebrales de hierro en una familia de donantes de sangre con sindrome de piernas inquietas.Introduccion. La fisiopatologia del sindrome de piernas inquietas (SPI) es compleja. El mecanismo a traves del cual la ferropenia favorece el desarrollo del SPI no esta esclarecido, aunque se sugiere la presencia de una alteracion en la homeostasis cerebral del hierro. Casos clinicos. Se presentan los hallazgos inusuales en una familia de donantes de sangre con SPI. Tres miembros de la misma familia fueron diagnosticados de SPI, cumpliendo los criterios definidos por el grupo internacional para el estudio del SPI (International Restless Legs Syndrome Study Group). Todos eran donantes de sangre habituales (rango de donacion: 10-40 años) y los sintomas de SPI tenian un curso de 3-5 años. La exploracion general y neurologica fue normal en todos los casos, asi como los electromiogramas. El estudio fenotipico y genotipico descarto la presencia de hemocromatosis y otras causas geneticas de sobrecarga cerebral de hierro. Los estudios polisomnograficos mostraron sueño nocturno perturbado, con reduccion de su eficiencia, y un aumento del indice de movimientos periodicos de las piernas. La resonancia magnetica craneal evidencio un aumento de los depositos cerebrales de hierro en los ganglios basales, la sustancia negra, el nucleo rojo y los dentados. Conclusion. Este aumento patologico de los depositos cerebrales de hierro sugiere la presencia de un complejo trastorno del metabolismo cerebral del hierro en nuestros pacientes. Futuros estudios deben confirmar estos hallazgos y profundizar en el estudio de su relacion con la fisiopatologia del SPI.

Long-term Excretion of Gadolinium-based Contrast Agents: Linear versus Macrocyclic Agents in an Experimental Rat Model.

Purpose To investigate the long-term course of MRI signal intensity (SI) changes and the presence of gadolinium in the rat brain during a 1-year period after multiple administrations of gadolinium-based contrast agents (GBCAs). Materials and Methods Rats received a linear GBCA (gadodiamide, gadopentetate dimeglumine, gadobenate dimeglumine), a macrocyclic GBCA (gadobutrol, gadoterate meglumine, gadoteridol), or saline. Animals received eight injections over 2 weeks (1.8 mmol/kg per injection). Brain MRI and gadolinium measurements were performed with inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS 5, 26, and 52 weeks after administration. Results Animals that received linear GBCAs showed higher deep cerebellar nuclei (DCN)-to-brainstem SI ratios compared with the saline group (P < .001 at all time points). After 1 year, mean gadolinium concentrations in the cerebellum were 3.38 nmol/g (gadodiamide), 2.13 nmol/g (gadopentetate dimeglumine), and 1.91 nmol/g (gadobenate dimeglumine). For linear agents, laser ablation ICP-MS revealed gadolinium depositions in the cerebellar nuclei. For macrocyclic GBCAs, the DCN-to-brainstem SI ratios did not significantly differ from those in the saline group (P > .42) and the cerebellar gadolinium concentrations decreased between weeks 5 and 52, reaching 0.08 nmol/g (gadobutrol), 0.04 nmol/g (gadoterate meglumine), and 0.07 nmol/g (gadoteridol). The respective laser ablation ICP-MS analysis showed no gadolinium depositions. Conclusion Increased signal intensity in the deep cerebellar nuclei of rats persists for at least 1 year after administration of linear gadolinium-based contrast agents (GBCAs), in line with persistent brain gadolinium concentrations with no elimination after the initial 5-week period. The animals that received macrocyclic GBCAs showed an ongoing elimination of gadolinium from the brain during the entire observation period. © RSNA, 2018.

Measurements of signal intensity of globus pallidus and dentate nucleus suggest different deposition characteristics of macrocyclic GBCAs in children.

INTRODUCTION: The safety of using GBCAs to enhance the visibility of body structures is currently discussed due to possible gadolinium retention in brain structures. The aim of the study was to evaluate the effect of multiple exposures to macrocyclic GBCAs in children. MATERIALS AND METHODS: This retrospective, single-center study included data from 43 patients who had received ≥4 injections of macrocyclic GBCAs during MRI examinations over performed over 8 to 84 months. Signal intensity was measured on unenhanced T1-weighted MRI, and globus pallidus to thalamus (GP/Th) and dentate nucleus to pons (DN/P) ratios were calculated. The differences in ratios were tested with the Student's t-test or the Wilcoxon rank sum test. For categorical data, Pearson's chi-squared test was used. Relationships were analyzed with the Spearman's rank correlation coefficient. RESULTS: Patients with the mean age of 7.5 years (SD = 4.2) received 8.19 (SD = 3.63) injections of GBCAs on average. Differences in GP/Th and DN/P ratios between the first and the last measurement were insignificant. Children before the end of myelination process (≤2 years of age) had the first GP/Th ratio values significantly lower than those >2 years of age (p = 0.0284), which than increased at the final scan and reached the level similar to values obtained in the group of >2 years of age. CONCLUSIONS: Maturation of the brain may affect both signal intensity of brain structures and susceptibility to GBCAs; thus, assessment of signal intensity of the brain structures should be conducted taking into account the age of a child.

Sox14 Is Required for a Specific Subset of Cerebello-Olivary Projections.

We identify Sox14 as an exclusive marker of inhibitory projection neurons in the lateral and interposed, but not the medial, cerebellar nuclei. Sox14+ neurons make up ∼80% of Gad1+ neurons in these nuclei and are indistinguishable by soma size from other inhibitory neurons. All Sox14+ neurons of the lateral and interposed cerebellar nuclei are generated at approximately E10/10.5 and extend long-range, predominantly contralateral projections to the inferior olive. A small Sox14+ population in the adjacent vestibular nucleus "Y" sends an ipsilateral projection to the oculomotor nucleus. Cerebellar Sox14+ and glutamatergic projection neurons assemble in non-overlapping populations at the nuclear transition zone, and their integration into a coherent nucleus depends on Sox14 function. Targeted ablation of Sox14+ cells by conditional viral expression of diphtheria toxin leads to significantly impaired motor learning. Contrary to expectations, associative learning is unaffected by unilateral Sox14+ neuron elimination in the interposed and lateral nuclei.SIGNIFICANCE STATEMENT The cerebellar nuclei are central to cerebellar function, yet how they modulate and process cerebellar inputs and outputs is still primarily unknown. Our study gives a direct insight into how nucleo-olivary projection neurons are generated, their projections, and their function in an intact behaving mouse. These neurons play a critical conceptual role in all models of cerebellar function, and this study represents the first specific analysis of their molecular identity and function and offers a powerful model for future investigation of cerebellar function in motor control and learning.

Multiple Administrations of Gadobutrol in the Pediatric Brain: No Change in T1 Signal at MRI.

Purpose To determine whether multiple doses of gadobutrol increase the T1 signal intensity in the brains of children. Materials and Methods This retrospective imaging study evaluated 91 children (median age, 5.4 years; age range, 0-17 years) with brain tumors who underwent five or more MR brain examinations at a single institution. A subgroup of 46 patients received five or more administrations of gadobutrol (0.1 mmol/kg) and underwent follow-up MRI. T1 signal intensity in the globus pallidus and dentate nucleus was measured at the first to sixth unenhanced MR brain examination in these children. Globus pallidus-to-corpus callosum and dentate nucleus-to-corpus callosum signal intensity ratios were analyzed by linear mixed-effect analysis. Subgroup analysis was performed for six children who underwent 14 or more administrations of gadobutrol. Results The globus pallidus-to-corpus callosum ratio increased with patient age (absolute change, 0.0052 per year; 95% confidence interval: 0.0033, 0.0071; P < .0001). There was no change in the dentate nucleus-to-corpus callosum ratio with age (P = .30). Among 46 children who received five or more doses of gadobutrol (median dose, 11 mL; range, 3.9-31 mL), there was no change in signal intensity ratio of the globus pallidus (P = .17) or dentate nucleus (P = .44). Among six children who underwent more than 14 administrations of gadobutrol (median dose, 64 mL; range, 40-91 mL) there was no change in signal intensity ratio of the globus pallidus (P = .15) or dentate nucleus (P = .50). Conclusion No increase in T1-weighted signal intensity ratio was observed in the globus pallidus or dentate nucleus after the administration of at least five doses of gadobutrol. © RSNA, 2018 Online supplemental material is available for this article.

[Value of 1H-MRS on SCA3/MJD diagnosis and clinical course].

OBJECTIVE: To investigate the value of proton magnetic resonance spectroscopy (1H-MRS) on the diagnosis of SCA3/MJD, and to calculate the correlation between 1H-MRS ratio and the clinical score.
 Methods: Sixteen patients with SCA3/MJD and 19 healthy volunteers were scanned with 1H-MRS. The data of N-acetyl aspartate, creatine, choline-containing compounds, myoinositol, NAA/Cr, Cho/Cr, and mI/Cr ratio were collected, which were grouped for comparative study. The onset patients with SCA3/MJD were evaluated with the International Cooperative Ataxia Rating Scale and Scale for the Assessment and Rating of Ataxia, the correlation between NAA/Cr, Cho/Cr or mI/Cr ratio and the clinical score was calculated.
 Results: The NAA/Cr in the pons and cerebellar dentate nucleus from the onset patients with SCA3/MJD was significantly reduced compared to that in the normal control group. The NAA/Cr in the cerebellar dentate nucleus of onset patients with SCA3/MJD was obviously correlated with ICARS.
 Conclusion: SCA3/MJD lesions are mainly located in the cerebellum and brainstem, where gray and white mater are also involved. The cerebellar dentate nucleus may be the earliest involved area. There is a correlation between the ICARS and the cerebellar lesion degree. The ICARS reflects the severity of clinical manifestations. 1H-MRS is useful in the diagnosis of SCA3/MJD.

MRI Brain Signal Intensity Changes of a Child During the Course of 35 Gadolinium Contrast Examinations.

We describe the observed and quantitative signal intensity changes in the brain on baseline precontrast T1-weighted MRI data of a pediatric patient who received 35 MRI examinations with gadolinium-based contrast agent (GBCA) between the ages of 8 and 20 years. The contrast agent this patient received belongs to a class of agents with linear molecular structures, which has been recently investigated in studies of gadolinium deposition in the brains of adult patients. Visual changes in signal intensity were assessed by 3 pediatric neuroradiologists, and progressive increases were the most evident in the dentate nuclei, the globus pallidus, and the thalamus. Quantitative measurements as determined from signal intensity ratios confirmed visual findings. The pattern of regional brain hyperintensity observed in this pediatric patient is consistent with findings from adult studies.

Bacterial colonization due to increased nurse workload in an intensive care unit / Colonização bacteriana por causa do aumento da carga de trabalho da equipe de enfermagem em unidade de terapia intensiva / Colonización bacteriana debido al aumento de la carga de trabajo del equipo de enfermería en una unidad de cuidados intensivos

INTRODUCTION: The rates of multiresistant bacteria colonization or infection (MRB+) development in intensive care units are very high. The aim of this study was to determine the possible association between the risk of development of nosocomial infections and increased daily nurse workload due to understaffing in intensive care unit. METHODS: We included 168 patients. Intensity of workload and applied procedures to patients were scored with the Project de Recherché en Nursing and the Omega scores, respectively. The criteria used for infections were those defined by the Centers for Disease Control. RESULTS: Of the 168 patients, 91 (54.2%) were female and 77 (45.8%) were male patients. The mean age of female and male was 64.9 ± 6.2 years and 63.1 ± 11.9 years, respectively. The mean duration of hospitalization in intensive care unit was 18.4 ± 6.1 days. Multiresistant bacteria were isolated from cultures of 39 (23.2%) patients. The development of MRB+ infection was correlated with length of stay, Omega 1, Omega 2, Omega 3, Total Omega, daily PRN, and Total PRN (p < 0.05). There was no correlation between development of MRB+ infection with gender, age and APACHE-II scores (p > 0.05). CONCLUSION: The risk of nosocomial infection development in an intensive care unit is directly correlated with increased nurse workload, applied intervention, and length of stay. Understaffing in the intensive care unit is an important health problem that especially affects care-needing patients. Nosocomial infection development has laid a heavy burden on the economy of many countries. To control nosocomial infection development in the intensive care unit, nurse workload, staffing level, and working conditions must be arranged. .

INTRODUÇÃO: As taxas de desenvolvimento de infecção ou colonização por bactérias multirresistentes (BMR+) em unidades de terapia intensiva são muito elevadas. O objetivo deste estudo foi determinar a possível associação entre o risco de desenvolvimento de infecções hospitalares e o aumento da carga de trabalho diária da equipe de enfermagem devido à insuficiência de pessoal em unidade de terapia intensiva. MÉTODOS: Cento e sessenta e oito pacientes foram incluídos. O volume da carga de trabalho e os procedimentos realizados em pacientes foram avaliados com o uso de instrumentos de medidas como o Projeto de Pesquisa em Enfermagem (Project de Recherché en Nursing) e o Omega, respectivamente. Os critérios usados para definir infecções foram os definidos pelos Centros de Controle de Doenças. RESULTADOS: Dos 168 pacientes, 91 (54,2%) eram do sexo feminino e 77 (45,8%) do sexo masculino. As médias das idades de mulheres e homens foram 64,9 ± 6,2 e 63,1 ± 11,9 anos, respectivamente. A média do tempo de internação em unidade de terapia intensiva foi de 18,4 ± 6,1 dias. As bactérias multirresistentes foram isoladas a partir de culturas de 39 (23,2%) pacientes. O desenvolvimento de infecção por BMR+ foi correlacionado com tempo de internação, Omega 1, Omega 2, Omega 3, Omega total, PPE diário e PPE total (p < 0,05). Não houve correlação entre desenvolvimento de infecção por BMR+ e gênero, idade e escores no APACHE-II (p > 0,05). CONCLUSÃO: O risco de desenvolvimento de infecção hospitalar em unidade de terapia intensiva está diretamente relacionado com o aumento da carga de trabalho de enfermagem, as intervenções praticadas e o tempo de internação. A falta de pessoal em unidade de terapia intensiva é um problema de saúde importante que afeta principalmente os pacientes que requerem cuidados. A infecção hospitalar colocou um fardo pesado sobre a economia de muitos países. Para controlar o desenvolvimento de infecção hospitalar em UTI, a carga ...

INTRODUÇÃO: as taxas de desenvolvimento de infecção ou colonização por bactérias multirresistentes [BMR (+)] em unidades de terapia intensiva são muito elevadas. O objetivo deste estudo foi determinar a possível associação entre o risco de desenvolvimento de infecções hospitalares e o aumento da carga de trabalho diária da equipe de enfermagem por causa da insuficiência de pessoal em unidade de terapia intensiva. MÉTODOS: foram incluídos 168 pacientes. O volume da carga de trabalho e os procedimentos feitos em pacientes foram avaliados com o uso de instrumentos de medidas como o Projeto de Pesquisa em Enfermagem (Project de Recherché en Nursing) e o Omega, respectivamente. Os critérios usados para definir infecções foram os estabelecidos pelos Centros de Controle de Doenças. RESULTADOS: dos 168 pacientes, 91 (54,2%) eram do sexo feminino e 77 (45,8%) do masculino. As médias das idades de mulheres e homens foram 64,9 ± 6,2 e 63,1 ± 11,9 anos, respectivamente. A média do tempo de internação em unidade de terapia intensiva foi de 18,4 ± 6,1 dias. As bactérias multirresistentes foram isoladas a partir de culturas de 39 (23,2%) pacientes. O desenvolvimento de infecção por BMR (+) foi correlacionado com tempo de internação, Omega 1, Omega 2, Omega 3, Omega total, PPE diário e PPE total (p < 0,05). Não houve correlação entre desenvolvimento de infecção por BMR (+) e gênero, idade e escores no Apache-II (p > 0,05). CONCLUSÃO: o risco de desenvolvimento de infecção hospitalar em unidade de terapia intensiva está diretamente relacionado com o aumento da carga de trabalho de enfermagem, as intervenções praticadas e o tempo de internação. A falta de pessoal em unidade de terapia intensiva é um problema de saúde importante que afeta principalmente os pacientes que requerem cuidados. A infecção hospitalar colocou um fardo pesado sobre a economia de muitos países. Para controlar o desenvolvimento de infecção hospitalar em UTI, a carga de trabalho ...

INTRODUCCIÓN: Las tasas de desarrollo de infección o colonización por bacterias multirresistentes en unidades de cuidados intensivos son muy elevadas. El objetivo de este estudio fue determinar la posible asociación entre el riesgo de desarrollo de infecciones hospitalarias y el aumento de la carga de trabajo diaria del equipo de enfermería debido a la falta de personal en la unidad de cuidados intensivos. MÉTODOS: Ciento sesenta y ocho pacientes fueron incluidos. El volumen de la carga de trabajo y los procedimientos realizados en pacientes fueron evaluados con el uso de instrumentos de medidas como el Proyecto de Investigación en Enfermería (Project de Recherché en Nursing) y el Omega, respectivamente. Los criterios usados para definir infecciones fueron los definidos por los Centros de Control de Enfermedades. RESULTADOS: De los 168 pacientes, 91 (54,2%) eran del sexo femenino y 77 (45,8%) del sexo masculino. La edad media de las mujeres y de los hombres fueron 64,9 ± 6,2 y 63,1 ± 11,9 años, respectivamente. El tiempo medio de ingreso en la unidad de cuidados intensivos fue de 18,4 ± 6,1 días. Las bacterias multirresistentes fueron aisladas a partir de cultivos de 39 (23,2%) pacientes. El desarrollo de infección por bacterias multirresistentes fue correlacionado con el tiempo de ingreso, Omega 1, Omega 2, Omega 3, Omega total, PPE diario y PPE total (p < 0,05). No hubo correlación entre el desarrollo de la infección por bacterias multirresistentes y el sexo, la edad y las puntuaciones en el APACHE-II (p > 0,05). CONCLUSIÓN: El riesgo de desarrollo de infección hospitalaria en una unidad de cuidados intensivos está directamente relacionado con el aumento de la carga de trabajo de enfermería, las intervenciones practicadas y el tiempo de ingreso. La falta de personal en la unidad de cuidados intensivos es un problema de sanidad importante que afecta principalmente a los pacientes que necesitan esos cuidados. La infección hospitalaria ...

An in vivo 1H magnetic resonance spectroscopy study of the deep cerebellar nuclei in children with fetal alcohol spectrum disorders.

BACKGROUND: Prenatal alcohol exposure has been linked to impairment in cerebellar structure and function, including eyeblink conditioning. The deep cerebellar nuclei, which play a critical role in cerebellar-mediated learning, receive extensive inputs from brain stem and cerebellar cortex and provide the point of origin for most of the output fibers to other regions of the brain. We used in vivo (1) H magnetic resonance spectroscopy (MRS) to examine effects of prenatal alcohol exposure on neurochemistry in this important cerebellar region. METHODS: MRS data from the deep cerebellar nuclei were acquired from 37 children with heavy prenatal alcohol exposure and 17 non- or minimally exposed controls from the Cape Coloured (mixed ancestry) community in Cape Town, South Africa. RESULTS: Increased maternal alcohol consumption around time of conception was associated with lower N-Acetylaspartate (NAA) levels in the deep nuclei (r = -0.33, p < 0.05). Higher levels of alcohol consumption during pregnancy were related to lower levels of the choline-containing metabolites (r = -0.37, p < 0.01), glycerophosphocholine plus phosphocholine (Cho). Alcohol consumption levels both at conception (r = 0.35, p < 0.01) and during pregnancy (r = 0.38, p < 0.01) were related to higher levels of glutamate plus glutamine (Glx). All these effects continued to be significant after controlling for potential confounders. CONCLUSIONS: The lower NAA levels seen in relation to prenatal alcohol exposure may reflect impaired neuronal integrity in the deep cerebellar nuclei. Our finding of lower Cho points to disrupted Cho metabolism of membrane phospholipids, reflecting altered neuropil development with potentially reduced content of dendrites and synapses. The alcohol-related alterations in Glx may suggest a disruption of the glutamate-glutamine cycling involved in glutamatergic excitatory neurotransmission.

The p62 antibody reveals various cytoplasmic protein aggregates in spinocerebellar ataxia type 6.

Neuronal protein aggregates are considered as pathological hallmarks of various human neurodegenerative diseases, including the so-called CAG-repeat disorders, such as spinocerebellar ataxia Type 6 (SCA6). Since the immunocytochemical findings of an initial post-mortem study using a specific antibody against the disease protein of SCA6 (i.e., pathologically altered alpha-1A subunit of the P/Q type voltage-dependent calcium channel, CACNA1A) have not been confirmed so far, the occurrence and central nervous system distribution of neuronal protein aggregates in SCA6 is still a matter of debate. Owing to the fact that the antibody against the pathologically altered CACNA1A is not commercially available, we decided to apply a recently generated p62 antibody on brain tissue from two clinically diagnosed and genetically confirmed SCA6 patients. Application of this p62 antibody revealed numerous cytoplasmic neuronal inclusions in the degenerated cerebellar dentate nucleus and inferior olive of both SCA6 patients studied, whereby a subset of these aggregates were also ubiquitin-immunopositive. In view of the known role of p62 in protein degradation as well as aggresome/sequestosome formation, the p62 aggregate formation observed in the present study suggests that SCA6 not only is associated with an impairment of the calcium channel function and an elongated polyglutamine stretch in CACNA1A, but also with a defective protein handling by the protein quality control system.

CD8 positive T-cell infiltration in the dentate nucleus of paraneoplastic cerebellar degeneration.

Recent reports have discussed the presence of cytotoxic T cells in paraneoplastic cerebellar degeneration (PCD). We report an autopsy case of PCD associated with anti-Hu antibody, in which we revealed infiltration of CD8+ T cells in and around the dentate nucleus but not in the cerebellar cortex, in addition to severe Purkinje cell loss. Some infiltrated mononuclear cells expressed cytotoxic cell marker, Granzyme B. Decrease of neurons and reduced presynapses were demonstrated in the dentate nucleus. This is the first report that suggests the possibility of the dentate nucleus being primarily attacked followed by Purkinje cell loss in PCD.

Iron, copper, and zinc distribution of the cerebellum.

Synchrotron rapid-scanning X-ray fluorescence (RS-XRF) is employed for the first time to simultaneously map iron, copper, and zinc in the normal cerebellum. The cerebellum is a major repository of metals that are essential to normal function. Therefore, mapping the normal metal distribution is an important first step towards understanding how multiple metals may induce oxidative damage, protein aggregation, and neurotoxicity leading to cerebellar degeneration in a wide range of diseases. We found that cerebellar white and grey matter could be sharply defined based upon the unique metal content of each region. The dentate nucleus was particularly metal-rich with copper localized to the periphery and iron and zinc abundant centrally. We discuss how RS-XRF metal mapping in the normal brain may yield important clues to the mechanisms of degeneration in the dentate nucleus.

Pathological tau burden and distribution distinguishes progressive supranuclear palsy-parkinsonism from Richardson's syndrome.

Clinical syndromes associated with progressive supranuclear palsy-tau pathology now include progressive supranuclear palsy-parkinsonism (PSP-P), in addition to classic Richardson's syndrome (RS) and pure akinesia with gait freezing (PAGF). Although pathological heterogeneity of progressive supranuclear palsy (PSP) has also been established, attempts to correlate this with clinical findings have only rarely provided conclusive results. The aim of this study was to investigate whether regional variations in the types of tau lesions or differences in overall tau load may explain the clinical differences between the RS, PSP-P and PAGF. Quantitative tau pathology assessment was performed in 17 brain regions in 42 cases of pathologically diagnosed PSP (22 RS, 14 PSP-P and 6 PAGF). Neurofibrillary tangles, tufted astrocytes, coiled bodies and thread pathology were quantitated and a grading system was developed separately for each region. Using these grades the overall tau load was calculated in each case. To establish a simplified system for grading the severity of tau pathology, all data were explored to identify the minimum number of regions that satisfactorily summarized the overall tau severity. The subthalamic nucleus, substantia nigra and globus pallidus were consistently the regions most severely affected by tau pathology. The mean severity in all regions of the RS group was higher than in PSP-P and PAGF, and the overall tau load was significantly higher in RS than in PSP-P (P = 0.002). Using only the grade of coiled body + thread lesions in the substantia nigra, caudate and dentate nucleus, a reliable and repeatable 12-tiered grading system was established (PSP-tau score: 0, mild tau pathology, restricted distribution; >7, severe, widespread tau pathology). PSP-tau score was negatively correlated with disease duration (Spearman's rho -0.36, P = 0.028) and time from disease onset to first fall (Spearman's rho -0.49, P = 0.003). The PSP-tau score in PSP-P (median 3, range 0-5) was significantly lower than in RS (median 5, range 2-10, Mann-Whitney U, P < 0.001). The two cases carrying the tau-H2 protective allele had the two lowest PSP-tau scores. We have identified significant pathological differences between the major clinical syndromes associated with PSP-tau pathology and the restricted, mild tau pathology in PSP-P supports its clinical distinction from RS. The grading system we have developed provides an easy-to-use and sensitive tool for the morphological assessment of PSP-tau pathology and allows for consideration of the clinical diversity that is known to occur in PSP.

The dentate nucleus in Friedreich's ataxia: the role of iron-responsive proteins.

Frataxin deficiency in Friedreich's ataxia (FRDA) causes cardiac, endocrine, and nervous system manifestations. Frataxin is a mitochondrial protein, and adequate amounts are essential for cellular iron homeostasis. The main histological lesion in the brain of FRDA patients is neuronal atrophy and a peculiar proliferation of synaptic terminals in the dentate nucleus termed grumose degeneration. This cerebellar nucleus may be especially susceptible to FRDA because it contains abundant iron. We examined total iron and selected iron-responsive proteins in the dentate nucleus of nine patients with FRDA and nine normal controls by biochemical and microscopic techniques. Total iron (1.53 +/- 0.53 mumol/g wet weight) and ferritin (206.9 +/- 46.6 mug/g wet weight) in FRDA did not significantly differ from normal controls (iron: 1.78 +/- 0.88 mumol/g; ferritin: 210.9 +/- 9.0 mug/g) but Western blots exhibited a shift to light ferritin subunits. Immunocytochemistry of the dentate nucleus revealed loss of juxtaneuronal ferritin-containing oligodendroglia and prominent ferritin immunoreactivity in microglia and astrocytes. Mitochondrial ferritin was not detectable by immunocytochemistry. Stains for the divalent metal transporter 1 confirmed neuronal loss while endothelial cells reacting with antibodies to transferrin receptor 1 protein showed crowding of blood vessels due to collapse of the normal neuropil. Regions of grumose degeneration were strongly reactive for ferroportin. Purkinje cell bodies, their dendrites and axons, were also ferroportin-positive, and it is likely that grumose degeneration is the morphological manifestation of mitochondrial iron dysmetabolism in the terminals of corticonuclear fibers. Neuronal loss in the dentate nucleus is the likely result of trans-synaptic degeneration.

Cerebellar fastigial neurons send bifurcating axons to both the left and right superior colliculus in cats.

Anesthetized cats were injected with 2% Fast Blue and 0.5% Nuclear Yellow into the intermediate and deep layers of the left and right superior colliculus, respectively. In the right caudal part of the cerebellar fastigial nucleus (cFN), double-labeling was found in 38.5% of the neurons labeled with Fast Blue, and in 11.5% of the neurons labeled with Nuclear Yellow. In the left cFN, 52.2% of the neurons labeled with Fast Blue and 11.0% of the neurons labeled with Nuclear Yellow were double-labeled. The results suggest a role of bifurcating fastigial fibers in cerebellar visual control.

Quantitative organization of neurotransmitters in the deep cerebellar nuclei of the Lurcher mutant.

The Lurcher mutant mouse is characterized by a primary selective loss of Purkinje cells, leading to the near total apoptotic death of these neurons. In contrast to the subsequent massive secondary degeneration of the granule cells and the inferior olivary neurons, only mild degeneration occurs in the deep cerebellar nuclei (DCN). However, it is not known to what extent the different populations of DCN neurons-glutamatergic principal projection neurons, gamma-aminobutyric acid (GABA)-ergic inferior olivary projection neurons, and glycinergic neurons-are affected in their neurotransmitter composition. To answer this question we studied the neurotransmitter contents (glutamate, GABA, and glycine) of DCN neurons and the size of synaptic boutons immunohistochemically on serial semithin sections in both Lurcher and wild-type mice. Applying the physical dissector counting method, our results confirmed the mild degeneration (a reduction by 20%) of large glutamatergic neurons and a more pronounced degeneration of GABAergic (by 42%) and glycinergic neurons (by 45%). On the other hand, an analysis of neurons colabeled for both GABA and glycine, revealed that this specific colabeling increased in the Lurcher mutant (by 40%). In addition, both the GABA-immunolabeled (IL) (by 56%) and the glycine-IL (by 45%) synaptic boutons showed an increase in diameter in the mutant. The density of these boutons showed a decrease of 30% each. In summary, the increase in the number of neurons colabeled for GABA and glycine, together with the increase in the size of the inhibitory synaptic boutons, could help in providing the minimum inhibition needed to maintain a residual "cerebellar" functionality in the Lurcher DCN.

Dexamethasone attenuates by colchicine induced Fos expression in the rat deep cerebellar and vestibular nuclei.

1. The intent of the present study was to find out whether dexamethasone pretreatment may affect the induction of Fos protein in cell nuclei of the cerebellar vestibular neuronal complex (CVNC) elicited by central administration of colchicine. Specifically, the rate of the dexamethasone-sensitive cell population was analyzed and compared at different levels of the CVNC using a light microscopic avidin-biotin peroxidase immunohistochemistry. 2. Male Wistar rats were pretreated with dexamethasone 3 days prior (2.5 mg/kg/day, s.c.) and 24 h after an intracerebroventricular delivery of colchicine (60 microg/10 microL). Animals were sacrificed 48 h after colchicine treatment by a transcardial perfusion with fixative. 3. Dexamethasone in itself had no effect on the activity of cells of the CVNC. However, in colchicine treated animals, which exhibited a large number of Fos-positive cells over the entire CVNC, the dexamethasone elicited a substantial reduction in the number of the Fos-immunoreactive cells over the CVNC. Distinct dexamethasone dependent reduction (50-90%) of Fos-immunoreactivity was observed in each of the deep cerebellar nuclei. On the other hand, less number of dexamethasone-sensitive cells were recognized in the vestibular structures. From these, maximal Fos-inhibition by dexamethasone was recognized in the medial vestibular nucleus, however, even in this case the number of suppressed cells did not exceed 50%. 4. The results provide for the first time evidence about the dexamethasone dependent reduction of Fos-immunoreactivity in the cells of the CVNC in response to stimulation elicited by colchicine. The data also indicate that the glucocorticoids might be involved in the regulation of some functions of the CVNC under stress conditions.