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From a case study, we describe the impact of unilateral lesion of the hand area in the primary motor cortex (M1) on manual dexterity and the role of the intact contralesional M1 in long-term functional recovery. An adult macaque monkey performed two manual dexterity tasks: ( i ) “modified Brinkman board” task, assessed simple precision grip versus complex precision grip, the latter involved a hand postural adjustment; ( ii ) “modified Klüver board” task, assessed movements ranging from power grip to precision grip, pre-shaping and grasping. Two consecutive unilateral M1 lesions targeted the hand area of each hemisphere, the second lesion was performed after stable, though incomplete, functional recovery from the primary lesion. Following each lesion, the manual dexterity of the contralesional hand was affected in a comparable manner, effects being progressively more deleterious from power grip to simple and then complex precision grips. Both tasks yielded consistent data, namely that the secondary M1 lesion did not have a significant impact on the recovered performance from the primary M1 lesion, which took place 5 months earlier. In conclusion, the intact contralesional M1 did not play a major role in the long-term functional recovery from a primary M1 lesion targeted to the hand area. [ABSTRACT FROM AUTHOR]

Background Multiple sclerosis can impair cognition from the early stages and has been shown to be associated with gray matter damage in addition to white matter pathology. Objectives To investigate the profile of cognitive impairment in clinically isolated syndrome (CIS), and the contribution of cortical inflammation, cortical and deep gray matter atrophy, and white matter lesions to cognitive decline. Methods Thirty patients with clinically isolated syndrome and twenty demographically- matched healthy controls underwent neuropsychologic assessment through the Rao Brief Repeatable Battery, and brain magnetic resonance imaging with double inversion recovery using a 3T scanner. Results Patients with clinically isolated syndrome performed significantly worse than healthy controls on tests that evaluated verbal memory, visuospatial learning and memory, and verbal fluency. Significant deep gray matter atrophy was found in the patients but cortical volume was not lower than the controls. Visual memory tests correlated with the volume of the hippocampus, cerebral white matter and deep gray matter structures and with cerebellar cortical atrophy. Cortical or white matter lesion load did not affect cognitive test results. Conclusion In our patients with CIS, it was shown that cognitive impairment was mainly related to cerebral white matter, cerebellar cortical and deep gray matter atrophy, but not with cortical inflammation, at least in the early stage of disease. [ABSTRACT FROM AUTHOR]

Highlights • Cortical involvement may exist in aquaporin-4-antibody-positive patients. • Conventional imaging is limited in evaluating cortical involvement. • Double inversion recovery imaging can help determine the location of the lesion. Abstract Background : Previous studies strongly suggested the absence of cortical involvement in neuromyelitis optica spectrum disorder. Methods : We describe two patients with anti-aquaporin-4 antibody and cortical lesions. Results : A 58-year-old and a 61-year-old woman presented with status epilepticus and right leg numbness, respectively. Double inversion recovery (DIR) and phase-sensitive inversion recovery (PSIR) imaging, magnetic resonance imaging sequences that enable the clear delineation of gray matter, revealed intracortical lesions and lesions located across the cortex and subcortex. Conclusion : Although rare, cortical involvement may exist in aquaporin-4 antibody-positive patients. DIR and PSIR MRI can help to determine the exact location of the lesion. [ABSTRACT FROM AUTHOR]

The importance of astrocyte heterogeneity came out as a hot topic in neurosciences especially over the last decades, when the development of new methodologies allowed demonstrating the existence of big differences in morphological, neurochemical and physiological features between astrocytes. However, although the knowledge about the biology of astrocytes is increasing rapidly, an important characteristic that remained unexplored, until the last years, has been the relationship between astrocyte lineages and cell heterogeneity. To fill this gap, a new method called StarTrack was recently developed, a powerful genetic tool that allows tracking astrocyte lineages forming cell clones. Using StarTrack , a single astrocyte progenitor and its progeny can be specifically labeled from its generation, during embryonic development, to its final fate in the adult brain. Because of this specific labeling, astrocyte clones, exhibiting heterogeneous morphologies and features, can be easily analyzed in relation to their ontogenetic origin. This review summarizes how astrocyte heterogeneity can be decoded studying the embryonic development of astrocyte lineages and their clonal relationship. Finally, we discuss about some of the challenges and opportunities emerging in this exciting area of investigation. [ABSTRACT FROM AUTHOR]

Background The HLA-DRB*1501 haplotype influences the risk of developing multiple sclerosis (MS), but it is not known how it affects grey matter pathology. Aim To assess HLA-DRB * 1501 effects on magnetic resonance imaging (MRI) cortical grey matter pathology. Methods Whole and lesional cortical grey matter volumes, lesional and normal-appearing grey matter magnetization transfer ratio were measured in 85 people with MS and 36 healthy control subjects. HLA-DRB * 1501 haplotype was determined by genotyping (rs3135388). Results No significant differences were observed in MRI measures between the HLA-DRB * 1501 subgroups. Conclusions The HLA-DRB * 1501 haplotype is not strongly associated with MRI-visible grey matter pathology. [ABSTRACT FROM AUTHOR]

Rationale and Objectives: Quantitative susceptibility mapping (QSM) is a novel technique which allows determining the bulk magnetic susceptibility distribution of tissue in vivo from gradient echo magnetic resonance (MR) phase images. Our purpose was to evaluate if there is additional diagnostic value of QSM images in detecting the cortical gray matter involvement in multiple sclerosis (MS) patients. Materials and Methods: Our institutional review board approved this study. Conventional MR imaging, including T2-weighted imaging and two- or three-dimensional fluid-attenuated inversion recovery images, and QSM imaging examinations were performed in 27 patients (19 male and eight female) with MS. Two radiologists (radiologists 1 and 2) assessed the MS lesions in the following 3 anatomic regions: intracortical, mixed white matter-gray matter (WM-GM), and juxtacortical regions. The numbers of lesions per region category were compared between conventional MR images with and without QSM images. Results: For radiologists 1 and 2, QSM images identified 6 (50.0%) and 7 (50.0%) additional lesions that were not seen in the conventional MR images, respectively. In a lesion-by-lesion analysis, the substantial fraction (20 [25.3%] of 79 at radiologist 1, 22 [29.7%] of 74 at radiologist 2) of juxtacortical white matter lesions on the conventional MR images were scored as mixed WM-GM lesions with QSM images. Conclusions: Our preliminary results suggest that the MR imaging with QSM may increase the sensitivity in cortical lesion detection in the MS brain and improved distinction between juxtacortical and mixed WM-GM lesions. [ABSTRACT FROM AUTHOR]

The article describes the case of a 56-year-old woman who had a six months history of violent, flinging involuntary movements of the left upper limb. A neurologist diagnosed the patient initially with epileptic disorder. A potential role of cortical lesions in causing uncommon movement disorders was suggested by the case.

Abstract: We investigated natural and lesion-induced apoptosis in the developing rat dorsal lateral geniculate nucleus (dLGN). These lesions involved: i) monocular enucleation, and ii) unilateral ablation of the visual cortex at different postnatal ages before eye opening. We identified dying cells as apoptotic with light and electron microscopy, using terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL), and immunohistochemistry for active caspase-3. In the dLGN of normal animals, TUNEL+cells were detected during the first postnatal week, with a peak at postnatal day (P) 1. Following enucleation at birth or at P7, the frequency of apoptotic cells in the contralateral dLGN increased significantly at postlesion day (PLD) 1 and returned to normal values by PLD7. In contrast to early lesions, enucleation at P14 did not induce significant changes in apoptosis in the dLGN. Cortical lesions performed at P0, P7 or at P14 induced the death of the overwhelming majority of cells in the ipsilateral dLGN, which led to a severe reduction in size of the nucleus by PLD7 and its complete elimination by adulthood. Double labeling with TUNEL and immunofluorescence for neuronal nuclear protein (NeuN) showed that in both normal and lesioned animals, apoptotic cells were mainly neurons. We suggest that: i) apoptosis in the dLGN occurs during the precritical period of neuronal maturation; ii) developing neurons in the dLGN are more dependent on the integrity of their connections with the visual cortex than with the retina for survival; and iii) lesion-induced apoptosis in the dLGN during development depends on the type and extent of the connectivity affected. [Copyright &y& Elsevier]

Abstract: We evaluated the pattern of apoptosis in the rat striatum during normal development and in two models of lesion-induced cell death. Lesions included i) unilateral ablations of the cerebral cortex at different postnatal ages, and ii) early postnatal lesions of the catecholaminergic afferent systems of the striatum with 6-hydroxydopamine (6-OHDA). Dying cells were identified as apoptotic using the TUNEL (terminal deoxynucleotidyl-transferase-mediated dUTP-biotin nick end labeling) method at the light and electron microscopic levels. Moreover, we used immunohistochemistry for the apoptotic markers active caspase-3 and fractin. TUNEL+ cells were present in the striatum during the first four postnatal weeks. Their frequency was high during the first postnatal week and peaked at postnatal day (P)5. Cortical lesions at birth, in contrast to those performed at later stages, induced a significant increase in the frequency of TUNEL+ cells in the ipsilateral striatum, which peaked at seven days postlesion. 6-OHDA lesions resulted in a similar and significant increase in the frequency of TUNEL+ cells in the striatum, which also peaked at P7. We also showed that cortical lesions at P0 and 6-OHDA lesions resulted in a reduction in the frequency, as well as in alterations of the morphology of γ-aminobutyric acid (GABA)-immunoreactive (ir) neurons in the striatum. We suggest that: i) apoptosis in the striatum is temporally coordinated with maturation events in this area and ii) early developmental lesions of major afferent pathways to the striatum affect both the survival and phenotype of striatal neurons. [Copyright &y& Elsevier]

Abstract: We have developed a two-lever choice reaction-time (RT) task to investigate the behavioral and neural mechanisms of stimulus–response compatibility in rats. In the task, the rat pressed two levers with its forepaws during the preparation period of each trial, and then quickly responded to an air-puff stimulus on its left or right forepaw by releasing the lever on the same side (compatible condition) or the opposite side (incompatible condition) of the stimulus. Twenty rats successfully learned the task in both the compatible and incompatible conditions. Two stimulus–response compatibility effects were observed: the RT was shorter and the error rate was lower in the compatible condition than in the incompatible condition. The trial sequence also affected the results and a speed-accuracy tradeoff was observed. These results are consistent with those reported for human RT tasks. Furthermore, a lesion in the forepaw-sensorimotor cortex caused increases in the RTs for stimulus detection and/or response movement with the contralateral forepaw, suggesting that the task was mediated by this brain area. We conclude that this instrumental task for rats can be regarded as a model for human RT tasks and can be used to investigate the neural basis of the compatibility effects. [Copyright &y& Elsevier]