Role of cortico-pallidal connectivity in the pathophysiology of dystonia

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The cortico-pallidal projection in the human: a tracking study with DT I technique

We investigated the globus pallidus starting from basal ganglia circuits scheme based on cortico-basal ganglia-thalamo-cortical loop. Globus pallidus represents the exit module from previous cited loop and having the role of locking or unlocking the motor gesture through its inhibition state. Such activities are regulated by direct, indirect and hyperdirect ways. Some studies demonstrated an immediate globus pallidus activation after cortex stimulation; another one provided the existence of a bundle of cortico-pallidal fibers, not crossing the neostriatum, in laboratory animals. Existence of such pathways is not demonstrated in human beings. Using DTI tecnique in this study we found an ipsilateral fiber bundle starting from prefrontal cortex and clearly directed to the globus pallidus. The existence of such direct cortico-pallidal projection, not crossing the neostriatum, was suggested by Testut and Latarjet and following asserted anatomically and by neuronography. Furthermore the presence of glutamatergic and dopaminergic receptors in the animal globus pallidus, already demonstrated in other studies, reinforces the validity of the results obtained in the present one also if should be important to demonstrate the presence of such receptors in humans

Normal basal ganglia variation in the human brain: an MRI and VBM based morphological and morphometrical analysis

In this report we highlighted basal ganglia morphology and volume differences in normal humans in comparison to gender and age sub-groups. We measured the volumes of the caudate nucleus, the putamen, and the globus pallidus on MR images of 52 healthy adults whose ages at baseline ranged between 20 and 84 years; we also made a comparison with lateral ventricles. The method applied is three-dimensional (3D) volume rendering starting from structural magnetic resonance imaging (MRI) studies of selected brain regions (basal ganglia e lateral ventricles). The analysis revealed a significant main effect of age, gender and craniometric index. Regarding gender subgroups the Mann–Whitney test showed significant differences between groups in the following parameters: Left putamen greater in males than in females, and Left pale nucleus greater in females than in males. Regarding age subgroups differences were found in subjects < 35 years old with statistical decrease of right caudate nucleus, meanwhile left caudate nucleus had no significant statistical differences. Regarding craniometric index subgroups significant differences between groups emerged only in both ventricular volumes. Our findings were consistent with literature and may shed light on some of the discrepancies in previous reports on basal ganglia volume shrinkage and ventricle volume enlargement

Endogenous orientation of visual attention in auditory space

Visuospatial attention is asymmetrically distributed with a leftward bias (i.e. pseudoneglect), while evidence for asymmetries in auditory spatial attention is still controversial. In the present study, we investigated putative asymmetries in the distribution of auditory spatial attention and the influence that visual information might have on its deployment. A modified version of the Posner task (i.e. the visuo-audio spatial task [VAST]) was used to investigate spatial processing of auditory targets when endogenous orientation of spatial attention was mediated by visual cues in healthy adults. A line bisection task (LBT) was also administered to assess the presence of a leftward bias in deployment of visuospatial attention. Overall, participants showed rightward and leftward biases in the VAST and the LBT, respectively. In the VAST, sound localization was enhanced by visual cues. Altogether, these findings support the existence of a facilitation effect for auditory targets originating from the right side of space and provide new evidence for crossmodal links in endogenous spatial attention between vision and audition

Distribution of costameric proteins in normal human ventricular and atrial cardiac muscle.

In the mature heart, the intercalated disc and costameres provide the cell-cell and cell-matrix junctions respectively. Intercalated disc is situated at the bipolar ends of the cardiomyocytes and the myofibrils are anchored at this structure. The costameres mediate integration with the extracellular matrix that covers individual cardiomyocytes laterally. Costameres are considered as "proteic machinery" that appears to comprise two protein complexes: the dystrophin-glycoprotein complex (DGC) and the vinculin-talin-integrin system. There are structural differences between atrial and ventricular myocytes, but there have been relatively few studies that have analyzed costameres and focal adhesion function in cardiac cells. Our previous study carried out only on atrial myocytes, demonstrated that the DGC and talin-vinculin-integrin complexes had a costameric distribution that, unlike skeletal muscle, it localized only on the I band. We performed a further immunohistochemical analysis extending also the evaluation to the normal human cardiac muscle fibers obtained from ventricle and interventricular septum, in order to define the distribution and the spatial relationship between the proteins of the two complexes also in the other heart districts. Immunoconfocal microscopy of cardiac tissue revealed the costameric distribution of DGC and of vinculin-talin-integrin system, the association of all tested proteins in intercalated disks, in disagreement with other Authors, and in T-tubule with irregular spokelike extensions penetrating toward the center of the cell. Moreover, our data showed that all tested proteins colocalize between each other

Distribution of costameric proteins in normal human ventricular and atrial cardiac muscle.

In the mature heart, the intercalated disc and costameres provide the cell-cell and cell-matrix junctions respectively. Intercalated disc is situated at the bipolar ends of the cardiomyocytes and the myofibrils are anchored at this structure. The costameres mediate integration with the extracellular matrix that covers individual cardiomyocytes laterally. Costameres are considered as "proteic machinery" that appears to comprise two protein complexes: the dystrophin-glycoprotein complex (DGC) and the vinculin-talin-integrin system. There are structural differences between atrial and ventricular myocytes, but there have been relatively few studies that have analyzed costameres and focal adhesion function in cardiac cells. Our previous study carried out only on atrial myocytes, demonstrated that the DGC and talin-vinculin-integrin complexes had a costameric distribution that, unlike skeletal muscle, it localized only on the I band. We performed a further immunohistochemical analysis extending also the evaluation to the normal human cardiac muscle fibers obtained from ventricle and interventricular septum, in order to define the distribution and the spatial relationship between the proteins of the two complexes also in the other heart districts. Immunoconfocal microscopy of cardiac tissue revealed the costameric distribution of DGC and of vinculin-talin-integrin system, the association of all tested proteins in intercalated disks, in disagreement with other Authors, and in T-tubule with irregular spokelike extensions penetrating toward the center of the cell. Moreover, our data showed that all tested proteins colocalize between each other

Real – time three-dimensional anatomical reconstruction of the human heart from normalized dataset

Four-dimensional (3D + time), real-time, cardiac image visualization is an important tool for anatomical procedure, particularly if the dynamic volumetric image can be registered to, and fused with the actual patient anatomy. 4D cardiac image visualization and manipulation platform, based on the opacity density radiation model, which exploits the power of modern graphics processing units in the rendering pipeline. A dynamic multiresolution display is implemented to enable the interactive selection and emphasis of volume of interest (VOI) within the entire contextual cardiac volume and to enhance performance, and a novel color and opacity adjustment algorithm is designed to increase the uniformity of the rendered multiresolution image of heart. Our system provides a visualization environment superior to noninteractive software-based implementations, but with a rendering speed that is comparable to traditional volume rendering approaches based on texture mapping

Real – time three-dimensional anatomical reconstruction of the human heart from normalized dataset

Four-dimensional (3D + time), real-time, cardiac image visualization is an important tool for anatomical procedure, particularly if the dynamic volumetric image can be registered to, and fused with the actual patient anatomy. 4D cardiac image visualization and manipulation platform, based on the opacity density radiation model, which exploits the power of modern graphics processing units in the rendering pipeline. A dynamic multiresolution display is implemented to enable the interactive selection and emphasis of volume of interest (VOI) within the entire contextual cardiac volume and to enhance performance, and a novel color and opacity adjustment algorithm is designed to increase the uniformity of the rendered multiresolution image of heart. Our system provides a visualization environment superior to noninteractive software-based implementations, but with a rendering speed that is comparable to traditional volume rendering approaches based on texture mapping

Structural connectivity‐based topography of the human globus pallidus: Implications for therapeutic targeting in movement disorders

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Red nucleus structure and function: from anatomy to clinical neurosciences

The red nucleus (RN) is a large subcortical structure located in the ventral midbrain. Although it originated as a primitive relay between the cerebellum and the spinal cord, during its phylogenesis the RN shows a progressive segregation between a magnocellular part, involved in the rubrospinal system, and a parvocellular part, involved in the olivocerebellar system. Despite exhibiting distinct evolutionary trajectories, these two regions are strictly tied together and play a prominent role in motor and non-motor behavior in different animal species. However, little is known about their function in the human brain. This lack of knowledge may have been conditioned both by the notable differences between human and non-human RN and by inherent difficulties in studying this structure directly in the human brain, leading to a general decrease of interest in the last decades. In the present review, we identify the crucial issues in the current knowledge and summarize the results of several decades of research about the RN, ranging from animal models to human diseases. Connecting the dots between morphology, experimental physiology and neuroimaging, we try to draw a comprehensive overview on RN functional anatomy and bridge the gap between basic and translational research