Neurofunctional correlates of eye to hand motor transfer.

This work investigates the transfer of motor learning from the eye to the hand and its neural correlates by using functional magnetic resonance imaging (fMRI) and a sensorimotor task consisting of the continuous tracking of a virtual target. In pretraining evaluation, all the participants (experimental and control group) performed the tracking task inside an MRI scanner using their right hand and a joystick. After which, the experimental group practiced an eye-controlled version of the task for 5 days using an eye tracking system outside the MRI environment. Post-training evaluation was done 1 week after the first scanning session, where all the participants were scanned again while repeating the manual pretraining task. Behavioral results show that the training in the eye-controlled task produced a better performance not only in the eye-controlled modality (motor learning) but also in the hand-controlled modality (motor transfer). Neural results indicate that eye to hand motor transfer is supported by the motor cortex, the basal ganglia and the cerebellum, which is consistent with previous research focused on other effectors. These results may be of interest in neurorehabilitation to activate the motor systems and help in the recovery of motor functions in stroke or movement disorder patients.

[Right hepatic bile duct injury: a single stage combined laparoscopic-endoscopic treatment]. / Lesión quirúrgica del conducto hepá tico derecho: tratamiento combinado laparoscópico-endoscópico.

Treatment of bile ducts injuries (BDI) treatment, combining minimally access surgical techniques, although their benefits, has been scarcely reported. We described a combined laparoscopic-endoscopic procedure, carried out in a patient with postoperative right hepatic duct (RHD) injury associated to laparoscopic cholecystectomy. Based on a clinical case description, we illustrate the surgical technique and assess their applicability and results. A biliary fistula was identified employing laparoscopic cholangiography and a metallic clip applied, producing RHD occlusion, was retrieved under fluoroscopic guidance. A biliary "rendezvous" maneuver was done for positioning an endoscopic biliary stent. The biliary fistula disappeared within two weeks and during 40-months of follow-up the patient remains asymptomatic. Laparoscopic-endoscopic approach, although technically demanding, resulted effective to treat this patient. A Continuous follow-up is essential for evaluating the long-term results.

The Mirror Neuron System in Relapsing Remitting Multiple Sclerosis Patients with Low Disability.

To study the visuospatial/visuoperceptive function using a mirror neuron system (MNS) based approach in multiple sclerosis (MS) patients and a healthy control group. Two task-based fMRIs (an execution task and an observation task) and one resting-fMRI were performed in a group of MS patients (n = 24) and a group of healthy controls (n = 15). The execution and observation tasks consisted of the performance or observation of the index-thumb opposition task. Statistical parametric mapping approaches were used to identify differences in the brain activity and functional connectivity (FC) of the MNS between MS patients and healthy controls. Furthermore, visuospatial and visuoperceptive evaluation was performed by a neuropsychologist on all the participants. No global differences between groups were identified when the activity during both the execution and the observation conditions was tested. Nevertheless, differences in FC maps were identified: healthy controls showed higher connectivity between the MNS regions (between the inferior parietal lobule and the inferior frontal gyrus bilaterally) than MS patients. The absence of differences between the studied groups may be the consequence of the selection of a cohort of MS patients with low disability and with no recent relapse. However, the presence of a decrease in functional connectivity within the MNS in MS patients could indicate the presence of subclinical disability in MNS functioning, not measurable by neuropsychological tests.

Modulation in the mirror neuron system when action prediction is not satisfied.

The ability to understand competitive games is closely connected to the mirror neuron system (MNS). This network is activated not only when an action is performed, but also when it is observed. Apart from allowing the understanding of actions performed by others, the MNS has been implicated in predicting subsequent actions. However, the results concerning the modulation of this network by the final outcome of these predictions are contradictory. These contradictions may be related to the use of complex experimental conditions. The aim of this research is to identify changes in the activity of the MNS when the predictions are or are not satisfied in a simple intransitive action-based game. An event-related functional magnetic resonance imaging study was conducted. It consisted of the observation of videos with two actors playing the well-known rock-paper-scissors game. The participants were asked to predict the response of the second actor when the first actor performed one of the three possible actions. In some videos (congruents) the prediction was satisfied, but in the rest of the videos (incongruents) the prediction was not satisfied. When the result was shown, higher activity in the MNS was observed in the congruent videos than in the incongruent ones. Therefore, the observation of a simple manual game leads to a significant activation of the MNS, and this activity seems to be modulated by the final outcome of a prediction, and when predictions are satisfied the activity is higher.

Komi type 2 pancreaticobiliary maljunction: Minimal access surgical treatment (with video).

Pancreaticobiliary maljunction (PBM) is associated with the development of neoplasms of bile ducts. Cholecystectomy with diversion of the biliary-pancreatic flow is considered the treatment of choice. To describe the surgical treatment employed for a patient with Komi's type 2 PBM and its long-term results. Laparoscopic common bile duct exploration, intraoperative cholangioscopy, and Roux-en-Y hepatico-jejunostomy were performed. Postoperative evolution was satisfactory. The patient was discharge 72 hours after the surgery. There was no associated morbidity. At 62-month follow-up, clinical examination, laboratory tests, and imaging studies confirmed an adequate patency of bilio-enteric anastomosis. The surgical approach employed was effective and safe, with satisfactory long-term results.

Diffuse optical tomography to measure functional changes during motor tasks: a motor imagery study.

The present work shows the spatial reliability of the diffuse optical tomography (DOT) system in a group of healthy subjects during a motor imagery task. Prior to imagery task performance, the subjects executed a motor task based on the finger to thumb opposition for motor training, and to corroborate the DOT spatial localization during the motor execution. DOT technology and data treatment allows us to distinguish oxy- and deoxyhemoglobin at the cerebral gyri level unlike the cerebral activations provided by fMRI series that were processed using different approaches. Here we show the DOT reliability showing functional activations at the cerebral gyri level during motor execution and motor imagery, which provide subtler cerebral activations than the motor execution. These results will allow the use of the DOT system as a monitoring device in a brain computer interface.

Visual inputs decrease brain activity in frontal areas during silent lipreading.

AIM: The aim of the present work is to analyze the modulation of the brain activity within the areas involved in lipreading when an additional visual stimulus is included. METHODS: The experiment consisted of two fMRI runs (lipreading_only and lipreading+picture) where two conditions were considered in each one (oral speech sentences condition [OSS] and oral speech syllables condition [OSSY]). RESULTS: During lipreading-only, higher activity in the left middle temporal gyrus (MTG) was identified for OSS than OSSY; during lipreading+picture, apart from the left MTG, higher activity was also present in the supplementary motor area (SMA), the left precentral gyrus (PreCG) and the left inferior frontal gyrus (IFG). The comparison between these two runs revealed higher activity for lipreading-only in the SMA and the left IFG. CONCLUSION: The presence of a visual reference during a lipreading task leads to a decrease in activity in frontal areas.

Is it necessary to show virtual limbs in action observation neurorehabilitation systems?

INTRODUCTION: Action observation neurorehabilitation systems are usually based on the observation of a virtual limb performing different kinds of actions. In this way, the activity in the frontoparietal Mirror Neuron System is enhanced, which can be helpful to rehabilitate stroke patients. However, the presence of limbs in such systems might not be necessary to produce mirror activity, for example, frontoparietal mirror activity can be produced just by the observation of virtual tool movements. The objective of this work was to explore to what point the presence of a virtual limb impacts the Mirror Neuron System activity in neurorehabilitation systems. METHODS: The study was conducted by using an action observation neurorehabilitation task during a functional magnetic resonance imaging (fMRI) experiment with healthy volunteers and comparing two action observation conditions that: 1 - included or 2 - did not include a virtual limb. RESULTS: It was found that activity in the Mirror Neuron System was similar during both conditions (i.e. virtual limb present or absent). CONCLUSIONS: These results open up the possibility of using new tasks that do not include virtual limbs in action observation neurorehabilitation environments, which can give more freedom to develop such systems.

The relationship between amplitude of low frequency fluctuations and gray matter volume of the mirror neuron system: Differences between low disability multiple sclerosis patients and healthy controls.

The study of the relationship between function and structure of the brain could be particularly interesting in neurodegenerative diseases like multiple sclerosis (MS). The aim of the present work is to identify differences of the amplitude of low frequency fluctuations (ALFF) in the mirror neuron system (MNS) between MS patients and healthy controls and to study the relationship between ALFF and the gray matter volume (GMV) of the regions that belong to the MNS. Relapsing-remitting MS patients with minor disability were compared to healthy controls (HC) using resting-state functional magnetic resonance imaging (fMRI), anatomic T1 weighted images and diffusion tensor imaging (DTI). Region of interest (ROI) analyses was performed in the MNS regions. A decrease of ALFF in MS patients was observed in the left inferior frontal gyrus (IFG). Furthermore, a correlation between ALFF in the IFG and the GMV of the left inferior parietal lobule (IPL) was identified. This relationship was different for MS patients than for HC, which may be associated with changes in diffusivity measures which were impaired in MS patients. MS patients with low disability may show ALFF differences in the MNS without clinical correspondence. This functional difference may be associated with cortical and subcortical changes related to the disease.

Comparing diffuse optical tomography and functional magnetic resonance imaging signals during a cognitive task: pilot study.

Diffuse optical tomography (DOT) measures concentration changes in both oxy- and deoxyhemoglobin providing three-dimensional images of local brain activations. A pilot study, which compares both DOT and functional magnetic resonance imaging (fMRI) volumes through t-maps given by canonical statistical parametric mapping (SPM) processing for both data modalities, is presented. The DOT series were processed using a method that is based on a Bayesian filter application on raw DOT data to remove physiological changes and minimum description length application index to select a number of singular values, which reduce the data dimensionality during image reconstruction and adaptation of DOT volume series to normalized standard space. Therefore, statistical analysis is performed with canonical SPM software in the same way as fMRI analysis is done, accepting DOT volumes as if they were fMRI volumes. The results show the reproducibility and ruggedness of the method to process DOT series on group analysis using cognitive paradigms on the prefrontal cortex. Difficulties such as the fact that scalp-brain distances vary between subjects or cerebral activations are difficult to reproduce due to strategies used by the subjects to solve arithmetic problems are considered. T-images given by fMRI and DOT volume series analyzed in SPM show that at the functional level, both DOT and fMRI measures detect the same areas, although DOT provides complementary information to fMRI signals about cerebral activity.

Subarachnoid hemorrhage and visuospatial and visuoperceptive impairment: disruption of the mirror neuron system.

Nearly 20 % of patients who suffer a subarachnoid hemorrhage (SAH) still display cognitive impairment even a year after follow-up. Visuospatial and visuoperceptive domains may be impaired in this cognitive impairment and may not have been fully studied in these patients. Furthermore, these cognitively impaired domains have been associated with activity in the so-called mirror neuron system (MNS). The aim of the study is to analyze the pattern of brain activity with an MNS task-based functional magnetic resonance imaging (fMRI) study in SAH patients. A complete neuropsychological assessment and fMRI study (with observation and execution conditions) were performed in patients with a history of SAH registered in the database of the Hospital Universitario de Canarias and a healthy control group. The patients had to meet all the following inclusion criteria for the study (less than 50 years old; SAH with a Fisher score 1-3; no vasospasm or ischemia; minimum follow-up of one year). Twelve SAH patients were studied. Three of which displayed visuospatial/visuoperceptive impairment. fMRI study showed the presence of higher activity in MNS regions in these patients than in patients with normal visuospatial/visuoperceptive functions. Furthermore, there was a negative correlation between the test scores and brain activity in premotor regions of the studied patients. SAH patients with visuospatial/visuoperceptive impairment have greater activity in the MNS regions. This finding may be associated with a subcortical dysfunction, leading to a disruption of neural activity and less efficient behavior of this brain network.

The mirror neuron system also rests.

The mirror neuron system (MNS) is a brain network that has been associated with the understanding of the actions performed by others. The main areas of the brain that are considered as belonging to the MNS are the rostral part of the inferior parietal lobe (IPL) and the inferior frontal gyrus (IFG). Many studies have tried to focus on the relationship between the regions belonging to the MNS, but a little consideration has been given to the study of the MNS in resting conditions. In the present experiment, the MNS has been studied by two fMRI modalities (task-based fMRI and resting-fMRI) and three analytical procedures [task-block comparison, functional connectivity (FC), and independent component analysis (ICA)]. The task-fMRI with block design showed a mirror activity located in the rostral IPL. The coordinates of this local maximum voxel were defined as a region of interest (ROI) for an FC analysis of the resting-fMRI. This analysis revealed the existence of a functional connectivity within regions forming the core of MNS network and also with other regions with mirror properties. Finally, resting-state fMRI ICA showed the same functional network, although it was more restricted to the core MNS regions. To the best of our knowledge, this is the first study that approaches the MNS using the resting-state fMRI analysis using independent component analysis and functional connectivity at the same time.

The effect of motor familiarity during simple finger opposition tasks.

Humans are more familiar with performing (and observing) index-thumb than with any other finger to thumb grasping and the effect of familiarity has not been tested specifically with simple and intransitive actions. The study of simple and intransitive motor actions (i.e. simple actions without need of object interaction) provides the opportunity to investigate specifically the brain motor regions reducing the effect of non-motor aspects that are related with more complex and/or transitive motor actions. The aim of this study is to evaluate brain activity patterns during the execution of simple and intransitive finger movements with different degrees of familiarity. With this in mind, a functional Magnetic Resonance Imaging (fMRI) study was performed in which participants were asked to execute finger to thumb opposition tasks with all the different fingers (index, middle, ring and little) with a fixed frequency (1 Hz) determined by a visual cue. This movement is considered as the pantomime of a precision grasping action. Significant activity was identified in the Sensory Motor Cortex (SMC), posterior parietal and premotor regions for all simple conditions (index-finger>control, middle-finger>control, ring-finger>control and little-finger>control). However, a linear trend contrast (index

Mapping the Mirror Neuron System in Neurosurgery.

BACKGROUND: Brain mapping is considered an important approach in neurosurgery to achieve better functional outcomes. The mirror neuron system (MNS) is a brain network implicated in understanding of action and imitation. No previous study has focused on identifying and monitoring the function of the MNS during the perioperative period in brain lesions. The aim of this study was to describe the application of a functional magnetic resonance imaging (fMRI) protocol to identify the MNS in a patient with a lesion in the premotor region. CASE DESCRIPTION: A specific fMRI protocol to identify regions belonging to the MNS was performed on a 19-year-old female patient who presented a cavernous angioma in the premotor region. The patient showed signs of impairment when imitating simple and complex hand movements. The fMRI protocol was performed before and 3 months after the surgical procedure. The protocol consisted of observation and execution conditions of a simple intransitive finger movement (precision grasping). MNS regions were identified during the pre- and postsurgical fMRI trials. Such mirror areas were respected during the procedure. The activation of these regions improved notably after the procedure, with a correlation between recovery of the ability to imitate simple and complex hand movements and higher and better-defined MNS activity. CONCLUSION: The use of an fMRI protocol with observation and execution conditions based on simple intransitive finger actions allows the easy identification and preservation of the MNS. Increased activity on postoperative fMRI may be associated with improvement in motor functions.

Lesión quirúrgica del conducto hepático derecho: tratamiento combinado laparoscópico-endoscópico / Right hepatic bile duct injury: a single stage combined laparoscopic-endoscopic treatment

RESUMEN El tratamiento de las lesiones quirúrgicas de las vías biliares (LQVB), empleando procedimientos quirúrgicos de mínimo acceso en forma conjunta, a pesar de sus beneficios, ha sido escasamente reportado. Describimos el tratamiento combinado láparoendoscópico, en una paciente con fístula biliar y estenosis postoperatoria del conducto hepático derecho (CHD). Con base en la descripción de un caso clínico, ilustramos la técnica quirúrgica y evaluamos su aplicabilidad y resultados. Empleando colangiografía laparoscópica, identificamos la fistula biliar y demostramos la oclusión del CHD por un clip metálico, el cual fue retirado mediante guía fluoroscópica. Realizamos maniobra de "rendezvous" biliar y colocamos de prótesis plástica endoscópica. La fístula biliar resolvió en 12 días y a 40 meses de seguimiento, la paciente permanece sin alteraciones. El abordaje láparo-endoscópico, aunque técnicamente demandante, resultó efectivo para el tratamiento de esta paciente. Su seguimiento es fundamental y de especial interés, a fin de evaluar los resultados a largo plazo.

ABSTRACT Treatment of bile ducts injuries (BDI) treatment, combining minimally access surgical techniques, although their benefits, has been scarcely reported. We described a combined laparoscopic-endoscopic procedure, carried out in a patient with postoperative right hepatic duct (RHD) injury associated to laparoscopic cholecystectomy. Based on a clinical case description, we illustrate the surgical technique and assess their applicability and results. A biliary fistula was identified employing laparoscopic cholangiography and a metallic clip applied, producing RHD occlusion, was retrieved under fluoroscopic guidance. A biliary "rendezvous" maneuver was done for positioning an endoscopic biliary stent. The biliary fistula disappeared within two weeks and during 40-months of follow-up the patient remains asymptomatic. Laparoscopic-endoscopic approach, although technically demanding, resulted effective to treat this patient. A Continuous follow-up is essential for evaluating the long-term results.

Síndrome de Mirizzi que simulaba una neoplasia biliar maligna / Mirizzi syndrome simulating a biliary malignant neoplasm

El síndrome de Mirizzi puede cursar con manifestaciones clínicas y hallazgos imagenológicos y de laboratorio, similares a los encontrados en las neoplasias biliares malignas. Se describe el caso de un paciente cuyo enfoque clínico inicial y estudios de imágenes aportaron datos sugerentes de neoplasia de las vías biliares. Los marcadores tumorales (CA 19-9, CEA) resultaron elevados. Una nueva evaluación clínica, la laparoscopia exploradora y la exploración endoscópica de las vías biliares, permitieron establecer el diagnóstico de síndrome de Mirizzi. Después de la extracción del cálculo biliar y de la anastomosis entre el conducto hepático y el yeyuno, el paciente permaneció asintomático. En este caso, la reevaluación clínica y el uso del protocolo adecuado de estudio, contribuyeron a orientar y confirmar el diagnóstico de síndrome de Mirizzi, lo cual determinó la conducta terapéutica más acertada

Mirizzi syndrome can occur with clinical manifestations and imaging and laboratory findings, similar to those found in malignant biliary neoplasms. We describe the case of a patient whose initial clinical approach and imaging studies provided data suggestive of bile duct neoplasia. Tumor markers (CA 19-9, CEA) were high. A new clinical evaluation, an explorative laparoscopy and endoscopic bile duct exploration allowed establish the diagnosis of Mirizzi syndrome. After removal the bile duct stone and to perform an hepatico jejunostomy the patient remained asymptomatic. In this case the clinical reevaluation and the use of the appropriate study proto-col contributed to guide and confirm the diagnosis of Mirizzi syndrome, which determined the most successful therapeutic approach

Enhancing sensorimotor activity by controlling virtual objects with gaze.

This fMRI work studies brain activity of healthy volunteers who manipulated a virtual object in the context of a digital game by applying two different control methods: using their right hand or using their gaze. The results show extended activations in sensorimotor areas, not only when participants played in the traditional way (using their hand) but also when they used their gaze to control the virtual object. Furthermore, with the exception of the primary motor cortex, regional motor activity was similar regardless of what the effector was: the arm or the eye. These results have a potential application in the field of the neurorehabilitation as a new approach to generate activation of the sensorimotor system to support the recovery of the motor functions.

Observation of simple intransitive actions: the effect of familiarity.

INTRODUCTION: Humans are more familiar with index - thumb than with any other finger to thumb grasping. The effect of familiarity has been previously tested with complex, specialized and/or transitive movements, but not with simple intransitive ones. The aim of this study is to evaluate brain activity patterns during the observation of simple and intransitive finger movements with differing degrees of familiarity. METHODOLOGY: A functional Magnetic Resonance Imaging (fMRI) study was performed using a paradigm consisting of the observation of 4 videos showing a finger opposition task between the thumb and the other fingers (index, middle, ring and little) in a repetitive manner with a fixed frequency (1 Hz). This movement is considered as the pantomime of a precision grasping action. RESULTS: Significant activity was identified in the bilateral Inferior Parietal Lobule and premotor regions with the selected level of significance (FDR [False Discovery Rate] = 0.01). The extent of the activation in both regions tended to decrease when the finger that performed the action was further from the thumb. More specifically, this effect showed a linear trend (index>middle>ring>little) in the right parietal and premotor regions. CONCLUSIONS: The observation of less familiar simple intransitive movements produces less activation of parietal and premotor areas than familiar ones. The most important implication of this study is the identification of differences in brain activity during the observation of simple intransitive movements with different degrees of familiarity.

A low cost fMRI-compatible tracking system using the Nintendo Wii remote.

It is sometimes necessary during functional magnetic resonance imaging (fMRI) experiments to capture different movements made by the subjects, e.g. to enable them to control an item or to analyze its kinematics. The aim of this work is to present an inexpensive hand tracking system suitable for use in a high field MRI environment. It works by introducing only one light-emitting diode (LED) in the magnet room, and by receiving its signal with a Nintendo Wii remote (the primary controller for the Nintendo Wii console) placed outside in the control room. Thus, it is possible to take high spatial and temporal resolution registers of a moving point that, in this case, is held by the hand. We tested it using a ball and racket virtual game inside a 3 Tesla MRI scanner to demonstrate the usefulness of the system. The results show the involvement of a number of areas (mainly occipital and frontal, but also parietal and temporal) when subjects are trying to stop an object that is approaching from a first person perspective, matching previous studies performed with related visuomotor tasks. The system presented here is easy to implement, easy to operate and does not produce important head movements or artifacts in the acquired images. Given its low cost and ready availability, the method described here is ideal for use in basic and clinical fMRI research to track one or more moving points that can correspond to limbs, fingers or any other object whose position needs to be known.