Francisco Marcano

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.

Anatomía patológica digital. Control de calidad y pato-informática

SUMMARY As in other hospital departments, histopathology and morbid anatomy require automation and quality control. Usually the PIS (Pathology information system) automates samples, images and reports and progressively incorporates PI (Pathology informatics), D-PATH (digital pathology), ePATH (electronic pathology), PPH (Patho-pharmacology), virtual autopsy and in general all types of translational research in the PMIS (pathology management information system). Not subject to a specific standard, quality control follows ISO-13485:2003 on services and medical devices, ISO 17025:2005 on technical aspects and ISO-15198:2003 for automatic and quantifiable procedures that, as medical software, is regulated by the new European directive on medical devices. For non-standardized procedures, users’ requirements for testing and calibration are essential. In our opinion, quality control requirements for virtual slides are not fulfilled in the majority of commercial systems. Future innovations in «solo-pathology» should see automated pathology laboratories, regulated by strict quality control, which include a telepathology backup to minimize diagnostic errors.

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.

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 (1Hz) 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<middle<ring<little) demonstrated that there was a linear increase of activity in the SMC (mainly in the Precentral Gyrus) while the finger used to perform the action was further from the thumb. Therefore, the execution of less familiar simple intransitive movements seems to lead to a stronger activation of the SMC than familiar ones. Posterior parietal and premotor regions did not show the aforementioned stronger activation. The most important implication of this study is the identification of differences in brain activity during the execution of simple intransitive movements with different degrees of familiarity.

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.

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.

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.

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.

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

Highlights • The study of the relationship between function and structure of the brain is interesting in multiple sclerosis patients.• Different relationship between amplitude of low frequency fluctuations (ALFF) and gray matter volume has been detected.• This difference may be associated with the presence of white matter lesions involving specific tracts.

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

Abstract. 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.