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A 15-year-old patient with sickle cell disease with recessive homozygous haemoglobin S/HbSS suffered several crises developmentally after the last of which the patient fell into coma. CT scan then revealed a large infarct of the right cerebral hemisphere. Three weeks after the event, the patient began to demonstrate spontaneous eye opening and spastic quadriparesis with no evidence of command-following, gestural or verbal communication, visual pursuit or purposeful motor behaviour. Our case was in an 'unresponsive wakefulness syndrome' with atrophy of lateral and frontal regions of both hemispheres, demonstrated by MRI and preservation of circulation in the posterior arterial system, documented by MR angiography. Currently observed are spontaneous eye opening, preserved visual and auditory startle reflexes, normal brainstem reflexes, and grasp, palmomental and sucking reflexes. Our case demonstrates partial recovery of awareness with significant brain lesions, reflecting preserved brain activity as an indication of the modular nature of functional networks.

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Auditory and visual pathways may be affected as a consequence of temporal lobe epilepsy surgery because of their anatomical relationships with this structure. The purpose of this paper is to correlate the results of the auditory and visual evoked responses with the parameters of tractography of the visual pathway, and with the state of connectivity between respective thalamic nuclei and primary cortices in both systems after the surgical resection of the epileptogenic zone in drug-resistant epileptic patients. Tractography of visual pathway and anatomical connectivity of auditory and visual thalamus-cortical radiations were evaluated in a sample of eight patients. In general, there was a positive relationship of middle latency response (MLR) latency and length of resection, while a negative correlation was found between MLR latency and the anatomical connection strength and anatomical connection probability of the auditory radiations. In the visual pathway, significant differences between sides were found with respect to the number and length of tracts, which was lower in the operated one. Anatomical connectivity variables and perimetry (visual field defect index) were particularly correlated with the latency of P100 wave which was obtained by quadrant stimulation. These results demonstrate an indirect functional modification of the auditory pathway and a direct traumatic lesion of the visual pathway after anterior temporal lobectomy in patients with drug resistant epilepsy.

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Sutton and Clauss presented a detailed review about the effectiveness of zolpidem, discussing recoveries from brain damage due to strokes, trauma and hypoxia. A significant finding has been the unexpected and paradoxical increment of brain activity in vegetative state/unresponsive wakefulness syndrome (VS/UWS). On the contrary, zolpidem is considered one of the best sleep inducers in normal subjects. We have studied series of VS/UWS cases after zolpidem intake. We have demonstrated EEG activation, increment of BOLD signal in different brain regions, and an autonomic influence, mainly characterized by a vagolytic chronotropic effect without a significant increment of the vasomotor sympathetic tone. As this autonomic imbalance might induce cardio- circulatory complications, which we didn't find in any of our patients, we suggest developing future trials under control of physiological indices by bedside monitoring. However, considering that the paradoxical arousing zolpidem effect might be certainly related to brain function improvement, we agree with Sutton and Clauss that future multicentre and multinational clinical trials should be developed, but under control of physiological indices.

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BACKGROUND: Voxel-based morphometric (VBM) studies in neuromyelitis optica (NMO) have shown limited reproducibility. A previous study suggests that the number of optic neuritis (ON) attacks may be a confounding factor when comparing NMO patients with controls if it is not taken into account during VBM analysis. PURPOSE: To investigate the potential confounding effect of the number of ON attacks, for both tissue volumes and perfusion by voxel-based statistical analysis. MATERIAL AND METHODS: Volumetric magnetic resonance imaging (MRI) and perfusion SPECT were obtained from 15 controls and two patient subgroups: subgroup I was composed of nine patients with one or two ON attacks; and subgroup II of six patients with three or four ON attacks. We performed non-parametric voxel-based comparison of tissue volumes and perfusion between controls versus the two patient subgroups and for the whole patient group. RESULTS: Subgroup I presented no volume reductions, contrary to subgroup II that showed unequivocal reduction. We also found hypoperfusion in different brain regions in different subgroups. The results were quite different for the whole patient group. CONCLUSION: These findings highlight the confounding effect of the number of ON attacks, providing a new methodological insight that could explain the limited reproducibility of previous VBM studies in NMO.

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INTRODUCTION: Zolpidem is a non-benzodiazepine drug used for the therapy of insomnia, which has selectivity for stimulating the effect of GABA-A receptors. Recently, a paradoxical arousing effect of zolpidem in patients with severe brain damage has been repeatedly reported. METHODS: A placebo-controlled magnetic resonance study was conducted to evaluate its effect on BOLD and metabolites spectral signals in a patient with severe brain injuries and an age-matched healthy volunteer. A multi-modal analysis was used to assess aspects in the pharmacologically-induced changes in the resting-state brain metabolism. RESULTS: A significantly increased BOLD signal was transiently localized in the left frontal cortices, bilateral anterior cingulated areas, left thalamus and right head of the caudate nucleus. The healthy subject showed a deactivation of the frontal, parietal and temporal cortices. BOLD signal changes were found to significantly correlate with concentrations of extravascular metabolites in the left frontal cortex. It is discussed that, when zolpidem attaches to modified GABA receptors of neurodormant brain cells, brain activation is induced. This might explain the significant correlations of BOLD signal changes and proton-MRS metabolites in this patient after zolpidem. CONCLUSION: It was concluded that proton-MRS and BOLD signal assessment could be used to study zolpidem-induced metabolic modulation in a resting state.

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Recent neuroimaging studies show that brain abnormalities in neuromyelitis optica (NMO) are more frequent than earlier described. Yet, more research considering multiple aspects of NMO is necessary to better understand these abnormalities. A clinical feature of relapsing NMO (RNMO) is that the incremental disability is attack-related. Therefore, association between the attack-related process and neuroimaging might be expected. On the other hand, the immunopathological analysis of NMO lesions has suggested that CNS microvasculature could be an early disease target, which could alter brain perfusion. Brain tissue volume changes accompanying perfusion alteration could also be expected throughout the attack-related process. The aim of this study was to investigate in RNMO patients, by voxel-based correlation analysis, the assumed associations between regional brain white (WMV) and grey matter volumes (GMV) and/or perfusion on one side, and the number of optic neuritis (ON) attacks, myelitis attacks and/or total attacks on the other side. For this purpose, high resolution T1-weighted MRI and perfusion SPECT imaging were obtained in 15 RNMO patients. The results showed negative regional correlations of WMV, GMV and perfusion with the number of ON attacks, involving important components of the visual system, which could be relevant for the comprehension of incremental visual disability in RNMO. We also found positive regional correlation of perfusion with the number of ON attacks, mostly overlapping the brain area where the WMV showed negative correlation. This provides evidence that brain microvasculature is an early disease target and suggests that perfusion alteration could be important in the development of brain structural abnormalities in RNMO.

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PURPOSE: Bone marrow stem cells (BMSC) were transplanted into the perilesional area in five patients bearing sequels of stroke, to evaluate the safety of the procedure and tolerance to the transplanted cells. METHODS: Cells were obtained from bone marrow samples taken from the same patient and stereotactically implanted into the targets, determined using a combination of images, and trans-operative recording of multiunit activity. The cells were implanted in several points along tracts in the perilesional region. RESULTS: No important adverse events derived from surgery or transplant were observed during the one year follow-up period, or detected using a combination of tests and functional measurements applied pre- and post-surgically. In contrast, some improvements were observed regarding the neurological condition of the patients, but the small number of patients in the study does not allow any conclusive statement. CONCLUSIONS: Our results demonstrate that BMSC can be safely transplanted into the brain of patients, with excellent tolerance and without complications, using the methods described here.

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This paper extends a previously formulated deterministic metabolic/hemodynamic model for the generation of blood oxygenated level dependent (BOLD) responses to include both physiological and observation stochastic components (sMHM). This adds a degree of flexibility when fitting the model to actual data by accounting for un-modelled activity. We then show how the innovation method can be used to estimate unobserved metabolic/hemodynamic as well as vascular variables of the sMHM, from simulated and actual BOLD data. The proposed estimation method allowed for doing model comparison by calculating the model's AIC and BIC. This methodology was then used to select between different neurovascular coupling assumptions underlying sMHM. The proposed framework was first validated on simulations and then applied to BOLD data from a motor task experiment. The models under comparison in the analysis of the actual data considered that vascular response was coupled to: (I) inhibition, (II) excitation, (III) both excitation and inhibition. Data was best described by model II, although model III was also supported.

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En este trabajo se aborda la cuantificación relativa del flujo sanguíneo cerebral (FSC) mediante SPECT y cómo mejorar dicha cuantificación con la tecnología existente en nuestro país. Se demuestra que esta cuantificación se puede mejorar por dos vías: mejorando la resolución espacial tomográfica; y generalizando el método de cuantificación relativa que utiliza al cerebelo como región de referencia, considerada la mejor región para el proceso de normalización de las imágenes de SPECT. Con este fin, se desarrollaron y validaron dos métodos. El primer método permite mejorar la resolución espacial en un 18 por ciento, la cual es significativa para aquellos sistemas que no pueden ser modernizados con los más recientes avances tecnológicos. El segundo método consiste en un procedimiento de cuantificación relativa basado en un hecho fisiológico encontrado por los autores no reportado anteriormente. A partir de este hallazgo se define un nuevo valor de referencia, el "Pseudocerebelo", que permite generalizar al cerebelo como región de referencia, aplicable incluso a pacientes con hipoperfusión cerebelosa. Esta experiencia puede ser de utilidad en gran parte de América Latina, teniendo en cuenta que existen condiciones similares desde el punto de vista tecnológico.

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