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Find video protocols related to scientific articles indexed in Pubmed.
A neural network approach to fMRI binocular visual rivalry task analysis.
PLoS ONE
PUBLISHED: 08-14-2014
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The purpose of this study was to investigate whether artificial neural networks (ANN) are able to decode participants' conscious experience perception from brain activity alone, using complex and ecological stimuli. To reach the aim we conducted pattern recognition data analysis on fMRI data acquired during the execution of a binocular visual rivalry paradigm (BR). Twelve healthy participants were submitted to fMRI during the execution of a binocular non-rivalry (BNR) and a BR paradigm in which two classes of stimuli (faces and houses) were presented. During the binocular rivalry paradigm, behavioral responses related to the switching between consciously perceived stimuli were also collected. First, we used the BNR paradigm as a functional localizer to identify the brain areas involved the processing of the stimuli. Second, we trained the ANN on the BNR fMRI data restricted to these regions of interest. Third, we applied the trained ANN to the BR data as a 'brain reading' tool to discriminate the pattern of neural activity between the two stimuli. Fourth, we verified the consistency of the ANN outputs with the collected behavioral indicators of which stimulus was consciously perceived by the participants. Our main results showed that the trained ANN was able to generalize across the two different tasks (i.e. BNR and BR) and to identify with high accuracy the cognitive state of the participants (i.e. which stimulus was consciously perceived) during the BR condition. The behavioral response, employed as control parameter, was compared with the network output and a statistically significant percentage of correspondences (p-value <0.05) were obtained for all subjects. In conclusion the present study provides a method based on multivariate pattern analysis to investigate the neural basis of visual consciousness during the BR phenomenon when behavioral indicators lack or are inconsistent, like in disorders of consciousness or sedated patients.
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A superfluorinated molecular probe for highly sensitive in vivo(19)F-MRI.
J. Am. Chem. Soc.
PUBLISHED: 06-06-2014
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(19)F-MRI offers unique opportunities to image diseases and track cells and therapeutic agents in vivo. Herein we report a superfluorinated molecular probe, herein called PERFECTA, possessing excellent cellular compatibility, and whose spectral properties, relaxation times, and sensitivity are promising for in vivo (19)F-MRI applications. The molecule, which bears 36 equivalent (19)F atoms and shows a single intense resonance peak, is easily synthesized via a simple one-step reaction and is formulated in water with high stability using trivial reagents and methods.
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Accuracy of 2-hydroxyglutarate quantification by short-echo proton-MRS at 3 T: a phantom study.
Phys Med
PUBLISHED: 03-04-2014
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We set out to investigate the potential confounding effect of variable concentration of N-acetyl-l-aspartate (NAA) and Glutamate (Glu) on measurement of the brain oncometabolite 2-hydroxyglutarate (2HG) using a standard MRS protocol. This issue may arise due to spectral overlap at clinical magnetic field strengths and thus complicate the usage of 2HG as a putative biomarker of gliomas bearing mutations of the isocitrate dehydrogenase (IDH) 1 and 2 genes.
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Cerebrovascular reactivity by quantitative magnetic resonance angiography with a Co? challenge. Validation as a new imaging biomarker.
Eur J Radiol
PUBLISHED: 03-03-2014
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Assessment of cerebrovascular reactivity (CVR) is essential in cerebrovascular diseases, as exhausted CVR may enhance the risk of cerebral ischemic events. Transcranial Doppler (TCD) with a vasodilatory stimulus is currently used for CVR evaluation. Scanty data are available for Quantitative Magnetic Resonance Angiography (QMRA), which supplies higher spatial resolution and quantitative cerebral blood flow values. Aims of our pilot study were: (a) to assess safety and feasibility of CO2 administration during QMRA, (b) evaluation of CVR under QMRA compared to TCD, and (c) quantitative evaluation of blood flow from the major intracranial arterial vessels both at rest and after CO2. CVR during 5% CO2 air breathing was measured with TCD as a reference method and compared with QMRA. Fifteen healthy subjects (age 60.47 ± 2.24; male 11/15) were evaluated at rest and during CO2 challenge. Feasibility and safety of QMRA under CO2 were ensured in all subjects. CVR from middle cerebral artery territory was not statistically different between TCD and MRI (p>0.05). Mean arterial pressure (MAP) and heart rate (HR) increased during QMRA and TCD (MAP p=0.007 and p=0.001; HR p=0.043 and p=0.068, respectively). Blood flow values from all intracranial vessels increased after CO2 inhalation (p<0.001). CO2 administration during QMRA sessions is safe and feasible. Good correlation in terms of CVR was obtained comparing TCD and QMRA. Blood flow values significantly increased from all intracranial arterial vessels after CO2. Studies regarding CVR in physiopathological conditions might consider the utilization of QMRA both in routine clinical settings and in research projects.
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Survival effect of first- and second-line treatments for patients with primary glioblastoma: a cohort study from a prospective registry, 1997-2010.
Neuro-oncology
PUBLISHED: 01-23-2014
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Prospective follow-up studies of large cohorts of patients with glioblastoma (GBM) are needed to assess the effectiveness of conventional treatments in clinical practice. We report GBM survival data from the Brain Cancer Register of the Fondazione Istituto Neurologico Carlo Besta (INCB) in Milan, Italy, which collected longitudinal data for all consecutive patients with GBM from 1997 to 2010.
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Preoperative mapping of the sensorimotor cortex: comparative assessment of task-based and resting-state FMRI.
PLoS ONE
PUBLISHED: 01-01-2014
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Resting state fMRI (rs-fMRI) has recently been considered as a possible complement or alternative to task-based fMRI (tb-fMRI) for presurgical mapping. However, evidence of its usefulness remains scant, because existing studies have investigated relatively small samples and focused primarily on qualitative evaluation. The aim of this study is to investigate the clinical usefulness of rs-fMRI in the context of presurgical mapping of motor functions, and in particular to determine the degree of correspondence with tb-fMRI which, while not a gold-standard, is commonly used in preoperative setting. A group of 13 patients with lesions close to the sensorimotor cortex underwent rs-fMRI and tb-fMRI to localize the hand, foot and mouth motor areas. We assessed quantitatively the degree of correspondence between multiple rs-fMRI analyses (independent-component and seed-based analyses) and tb-fMRI, with reference to sensitivity and specificity of rs-fMRI with respect to tb-fMRI, and centre-of-mass distances. Agreement with electro-cortical stimulation (ECS) was also investigated, and a traditional map thresholding approach based on agreement between two experienced operators was compared to an automatic threshold determination method. Rs-fMRI can localize the sensorimotor cortex successfully, providing anatomical specificity for hand, foot and mouth motor subregions, in particular with seed-based analyses. Agreement with tb-fMRI was only partial and rs-fMRI tended to provide larger patterns of correlated activity. With respect to the ECS data available, rs-fMRI and tb-fMRI performed comparably, even though the shortest distance to stimulation points was observed for the latter. Notably, the results of both were on the whole robust to thresholding procedure. Localization performed by rs-fMRI is not equivalent to tb-fMRI, hence rs-fMRI cannot be considered as an outright replacement for tb-fMRI. Nevertheless, since there is significant agreement between the two techniques, rs-fMRI can be considered with caution as a potential alternative to tb-fMRI when patients are unable to perform the task.
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Parametric response maps of perfusion MRI may identify recurrent glioblastomas responsive to bevacizumab and irinotecan.
PLoS ONE
PUBLISHED: 01-01-2014
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Perfusion weighted imaging (PWI) can be used to measure key aspects of tumor vascularity in vivo and recent studies suggest that perfusion imaging may be useful in the early assessment of response to angiogenesis inhibitors. Aim of this work is to compare Parametric Response Maps (PRMs) with the Region Of Interest (ROI) approach in the analysis of tumor changes induced by bevacizumab and irinotecan in recurrent glioblastomas (rGBM), and to evaluate if changes in tumor blood volume measured by perfusion MRI may predict clinical outcome.
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Substantia nigra in Parkinsons disease: a multimodal MRI comparison between early and advanced stages of the disease.
Neurol. Sci.
PUBLISHED: 07-03-2013
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This study focused on the substantia nigra (SN) in Parkinsons disease (PD). We measured its area and volume, mean diffusivity (MD), fractional anisotropy (FA) and iron concentration in early and late PD and correlated the values with clinical scores. Twenty-two early PD (EPD), 20 late PD (LPD) and 20 healthy subjects (age 64.7 ± 4.9, 60.5 ± 6.1, and 61 ± 7.2 years, respectively) underwent 1.5 T MR imaging with double-TI-IR T1-weighted, T2*-weighted and diffusion tensor imaging scans. Relative SN area, MD, FA and R2* were measured in ROIs traced on SN. Correlation with Unified Parkinson Disease Rating Scale (UPDRS) scores was assessed. In LPD, the SN area was significantly reduced with respect to EPD (p = 0.04) and control subjects (p < 0.001). In EPD, the SN area was also significantly smaller than in controls (p = 0.006). Similarly, the SN volume significantly differed between LPD and controls (p = 0.001) and between EPD and LPD (p = 0.049), while no significant differences were found between controls and EPD. Both SN area (r = 0.47, p = 0.004) and volume (r = 0.46, p = 0.005) correlated with UPDRS scores. At 1.5 T, SN morphological measurements were sensitive to early PD changes and able to track the disease progression, while MD and FA measures and relaxometry did not provide significant results.
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The natural killer cell response and tumor debulking are associated with prolonged survival in recurrent glioblastoma patients receiving dendritic cells loaded with autologous tumor lysates.
Oncoimmunology
PUBLISHED: 06-27-2013
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Recurrent glioblastomas (GBs) are highly aggressive tumors associated with a 6-8 mo survival rate. In this study, we evaluated the possible benefits of an immunotherapeutic strategy based on mature dendritic cells (DCs) loaded with autologous tumor-cell lysates in 15 patients affected by recurrent GB. The median progression-free survival (PFS) of this patient cohort was 4.4 mo, and the median overall survival (OS) was 8.0 mo. Patients with small tumors at the time of the first vaccination (< 20 cm(3); n = 8) had significantly longer PFS and OS than the other patients (6.0 vs. 3.0 mo, p = 0.01; and 16.5 vs. 7.0 mo, p = 0.003, respectively). CD8(+) T cells, CD56(+) natural killer (NK) cells and other immune parameters, such as the levels of transforming growth factor ?, vascular endothelial growth factor, interleukin-12 and interferon ? (IFN?), were measured in the peripheral blood and serum of patients before and after immunization, which enabled us to obtain a vaccination/baseline ratio (V/B ratio). An increased V/B ratio for NK cells, but not CD8(+) T cells, was significantly associated with prolonged PFS and OS. Patients exhibiting NK-cell responses were characterized by high levels of circulating IFN? and E4BP4, an NK-cell transcription factor. Furthermore, the NK cell V/B ratio was inversely correlated with the TGF?2 and VEGF V/B ratios. These results suggest that tumor-loaded DCs may increase the survival rate of patients with recurrent GB after effective tumor debulking, and emphasize the role of the NK-cell response in this therapeutic setting.
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Connectivity of the amygdala, piriform, and orbitofrontal cortex during olfactory stimulation: a functional MRI study.
Neuroreport
PUBLISHED: 02-06-2013
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The majority of existing functional MRI studies on olfactory perception have addressed the relationship between stimulus features and the intensity of activity in separate regions considered in isolation. However, anatomical studies as well as neurophysiological recordings in rats and insects suggest that odor features may also be represented in a sparse manner through the simultaneous activity of multiple cortical areas interacting as a network. Here, we aimed to map the interdependence of neural activity among regions of the human brain, representing functional connectivity, during passive smelling. Seventeen healthy participants were scanned while performing a blocked-design task alternating exposure to two unpleasant odorants and breathing fresh air. High efferent connectivity was detected for the piriform cortex and the amygdala bilaterally. By contrast, the medial orbitofrontal cortex was characterized by high afferent connectivity, notably in the absence of an overall change in the intensity of hemodynamic activity during olfactory stimulation. Our results suggest that, even in the context of an elementary task, information on olfactory stimuli is scattered by the amygdala and piriform cortex onto an anatomically sparse representation and then gathered and integrated in the medial orbitofrontal cortex.
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Prognostic value of CD109+ circulating endothelial cells in recurrent glioblastomas treated with bevacizumab and irinotecan.
PLoS ONE
PUBLISHED: 01-01-2013
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Recent data suggest that circulating endothelial and progenitor cells (CECs and CEPs, respectively) may have predictive potential in cancer patients treated with bevacizumab, the antibody recognizing vascular endothelial growth factor (VEGF). Here we report on CECs and CEPs investigated in 68 patients affected by recurrent glioblastoma (rGBM) treated with bevacizumab and irinotecan and two Independent Datasets of rGBM patients respectively treated with bevacizumab alone (n=32, independent dataset A: IDA) and classical antiblastic chemotherapy (n=14, independent dataset B: IDB).
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Neuroradiological diagnosis of Chiari malformations.
Neurol. Sci.
PUBLISHED: 07-30-2011
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Chiari malformations 1, 2, 3 represent different degrees of herniation of posterior fossa content into the cervical canal (Chiari 1 and 2), or through an upper-cervical meningocele (Chiari 3), whereas Chiari 4 anomaly consists of hypoplasia of the cerebellum. Chiari 1 malformation (CM1) is the commonest anomaly; it is probably related to a mesodermal defect that create a congenitally small posterior fossa, subsequent overcrowding of its contents and herniation through the foramen magnum. The diagnosis of CM1 is based on the demonstration of the downward displacement and particular shape of the cerebellar tonsils into the upper cervical spinal canal associated with obliteration of the subarachnoid spaces at the level of the foramen magnum. MRI has a fundamental role in the correct identification of the anatomical aspects of this malformation and associated anomalies and represents the imaging modality of choice.
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Pain processing in medication overuse headache: a functional magnetic resonance imaging (fMRI) study.
Pain Med
PUBLISHED: 07-12-2011
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The primary aim was to investigate functional differences between medication overuse headache (MOH) patients and controls with the purpose of evaluating the presence of a global alteration in the processing of noxious stimuli throughout the pain matrix. The secondary aim was to investigate whether activations in MOH patients normalize after medication withdrawal, which would suggest a possible role of the pain matrix in headache chronification.
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Chronic migraine with medication overuse pre-post withdrawal of symptomatic medication: clinical results and FMRI correlations.
Headache
PUBLISHED: 07-13-2010
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Chronic migraine with symptomatic medication overuse (CMwMO) is a common and often debilitating clinical condition. Withdrawal of the offending drug(s) is considered the first step in management. Functional magnetic resonance imaging (fMRI) may be a useful technique for obtaining information on particular neuronal changes in the pain network involved in this condition.
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Quantitation of normal metabolite concentrations in six brain regions by in-vivoH-MR spectroscopy.
J Med Phys
PUBLISHED: 01-24-2010
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This study examined the concentrations of brain metabolites visible to in-vivo(1)H-Magnetic Resonance Spectroscopy ((1)H-MRS) at 1.5 T in a sample of 28 normal subjects. Quantitation was attempted for inositol compounds, choline units, total creatine and N-acetyl moieties, using open-source software. Six brain regions were considered: frontal and parietal white matter, medial temporal lobe, thalamus, pons and cerebellum. Absolute concentrations were derived using tissue water as an internal reference and using an external reference; metabolite signal intensity ratios with respect to creatine were also calculated. The inter-individual variability was smaller for absolute concentrations (internal reference) as compared to that for signal intensity ratios. Significant regional variability in concentration was found for all metabolites, indicating that separate normative values are needed for different brain regions. The values obtained in this study can be used as reference in future studies, provided the same methodology is followed; it is confirmed that despite unsuccessful attempts in the past, smaller coefficients of variation can indeed be obtained through absolute quantification.
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Effect of diffusion-sensitizing gradient timings on the exponential, biexponential and diffusional kurtosis model parameters: in-vivo measurements in the rat thalamus.
MAGMA
PUBLISHED: 01-13-2010
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To investigate whether spacing (Delta) and duration (delta) of the diffusion-sensitizing gradient pulses differentially affect exponential (D), biexponential (D (slow), D (fast) and f (slow)) and diffusional kurtosis (D and K) model parameters.
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Simultaneous EEG-fMRI in patients with Unverricht-Lundborg disease: event-related desynchronization/synchronization and hemodynamic response analysis.
Comput Intell Neurosci
PUBLISHED: 01-06-2010
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We performed simultaneous acquisition of EEG-fMRI in seven patients with Unverricht-Lundborg disease (ULD) and in six healthy controls using self-paced finger extension as a motor task. The event-related desynchronization/synchronization (ERD/ERS) analysis showed a greater and more diffuse alpha desynchronization in central regions and a strongly reduced post-movement beta-ERS in patients compared with controls, suggesting a significant dysfunction of the mechanisms regulating active movement and movement end. The event-related hemodynamic response obtained from fMRI showed delayed BOLD peak latency in the contralateral primary motor area suggesting a less efficient activity of the neuronal populations driving fine movements, which are specifically impaired in ULD.
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Genetic signature of adult gliomas and correlation with MRI features.
Expert Rev. Mol. Diagn.
PUBLISHED: 10-13-2009
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In recent years the amount of information concerning the genetics and the biology of gliomas, and particularly of glioblastoma multiforme, increased steadily. Such an increase has been paralleled by the technological progress of MRI. The merging of these scientific areas, as summarized in this review, is helping the stratification of glioma patients for clinical trials and their clinical follow-up. Although available therapeutic options appear limited in number, it is likely that in the next 5 years, both as a consequence of the increased knowledge due to genomic sequencing of hundreds of glioblastoma specimens and to continuous improvements of MRI, new perspectives will be available for these patients, with a sizable impact on their prognosis.
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Age-related iron deposition in the basal ganglia: quantitative analysis in healthy subjects.
Radiology
PUBLISHED: 06-30-2009
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To determine the values of iron accumulation in the basal ganglia of healthy volunteers of different ages with R2* and raw signal intensity measurements from T1-weighted magnetic resonance (MR) images, supported by voxel-based relaxometry (VBR), and to compare them with previously reported iron concentrations found in autopsy material.
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Functional MRI/event-related potential study of sensory consonance and dissonance in musicians and nonmusicians.
Neuroreport
PUBLISHED: 02-20-2009
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Pleasurability of individual chords, known as sensory consonance, is widely regarded as physiologically determined and has been shown to be associated with differential activity in the auditory cortex and in several other regions. Here, we present results obtained contrasting isolated four-note chords classified as consonant or dissonant in tonal music. Using event-related functional MRI, consonant chords were found to elicit a larger haemodynamic response in the inferior and middle frontal gyri, premotor cortex and inferior parietal lobule. The effect was right lateralized for nonmusicians and less asymmetric for musicians. Using event-related potentials, the degree of sensory consonance was found to modulate the amplitude of the P1 in both groups and of the N2 in musicians only.
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In medication-overuse headache, FMRI shows long-lasting dysfunction in midbrain areas.
Headache
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The primary aim of our study was to evaluate if a group of medication-overuse headache (MOH) patients present dysfunctions in the mesocorticolimbic dopamine circuit. The secondary aim was to disentangle the role of the medication overuse and of the acute/chronic headache in determining these alterations and to investigate their persistence.
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Thoughts turned into high-level commands: Proof-of-concept study of a vision-guided robot arm driven by functional MRI (fMRI) signals.
Med Eng Phys
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Previous studies have demonstrated the possibility of using functional MRI to control a robot arm through a brain-machine interface by directly coupling haemodynamic activity in the sensory-motor cortex to the position of two axes. Here, we extend this work by implementing interaction at a more abstract level, whereby imagined actions deliver structured commands to a robot arm guided by a machine vision system. Rather than extracting signals from a small number of pre-selected regions, the proposed system adaptively determines at individual level how to map representative brain areas to the input nodes of a classifier network. In this initial study, a median action recognition accuracy of 90% was attained on five volunteers performing a game consisting of collecting randomly positioned coloured pawns and placing them into cups. The "pawn" and "cup" instructions were imparted through four mental imaginery tasks, linked to robot arm actions by a state machine. With the current implementation in MatLab language the median action recognition time was 24.3s and the robot execution time was 17.7s. We demonstrate the notion of combining haemodynamic brain-machine interfacing with computer vision to implement interaction at the level of high-level commands rather than individual movements, which may find application in future fMRI approaches relevant to brain-lesioned patients, and provide source code supporting further work on larger command sets and real-time processing.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.