Cristián Modroño

Impact of contour on aesthetic judgments and approach-avoidance decisions in architecture

On average, we urban dwellers spend about 90% of our time indoors, and share the intuition that the physical features of the places we live and work in influence how we feel and act. However, there is surprisingly little research on how architecture impacts behavior, much less on how it influences brain function. To begin closing this gap, we conducted a functional magnetic resonance imaging study to examine how systematic variation in contour impacts aesthetic judgments and approach-avoidance decisions, outcome measures of interest to both architects and users of spaces alike. As predicted, participants were more likely to judge spaces as beautiful if they were curvilinear than rectilinear. Neuroanatomically, when contemplating beauty, curvilinear contour activated the anterior cingulate cortex exclusively, a region strongly responsive to the reward properties and emotional salience of objects. Complementing this finding, pleasantness—the valence dimension of the affect circumplex—accounted for nearly 60% of the variance in beauty ratings. Furthermore, activation in a distributed brain network known to underlie the aesthetic evaluation of different types of visual stimuli covaried with beauty ratings. In contrast, contour did not affect approach-avoidance decisions, although curvilinear spaces activated the visual cortex. The results suggest that the well-established effect of contour on aesthetic preference can be extended to architecture. Furthermore, the combination of our behavioral and neural evidence underscores the role of emotion in our preference for curvilinear objects in this domain.

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.

Activation of the human mirror neuron system during the observation of the manipulation of virtual tools in the absence of a visible effector limb.

This work explores the mirror neuron system activity produced by the observation of virtual tool manipulations in the absence of a visible effector limb. Functional MRI data was obtained from healthy right-handed participants who manipulated a virtual paddle in the context of a digital game and watched replays of their actions. The results show how action observation produced extended bilateral activations in the parietofrontal mirror neuron system. At the same time, three regions in the left hemisphere (in the primary motor and the primary somatosensory cortex, the supplementary motor area and the dorsolateral prefrontal cortex) showed a reduced BOLD, possibly related with the prevention of inappropriate motor execution. These results can be of interest for researchers and developers working in the field of action observation neurorehabilitation.

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.

Temporal Uncertainty and Temporal Estimation Errors Affect Insular Activity and the Frontostriatal Indirect Pathway during Action Update: A Predictive Coding Study.

Action update, substituting a prepotent behavior with a new action, allows the organism to counteract surprising environmental demands. However, action update fails when the organism is uncertain about when to release the substituting behavior, when it faces temporal uncertainty. Predictive coding states that accurate perception demands minimization of precise prediction errors. Activity of the right anterior insula (rAI) is associated with temporal uncertainty. Therefore, we hypothesize that temporal uncertainty during action update would cause the AI to decrease the sensitivity to ascending prediction errors. Moreover, action update requires response inhibition which recruits the frontostriatal indirect pathway associated with motor control. Therefore, we also hypothesize that temporal estimation errors modulate frontostriatal connections. To test these hypotheses, we collected fMRI data when participants performed an action-update paradigm within the context of temporal estimation. We fit dynamic causal models to the imaging data. Competing models comprised the inferior occipital gyrus (IOG), right supramarginal gyrus (rSMG), rAI, right presupplementary motor area (rPreSMA), and the right striatum (rSTR). The winning model showed that temporal uncertainty drove activity into the rAI and decreased insular sensitivity to ascending prediction errors, as shown by weak connectivity strength of rSMG→rAI connections. Moreover, temporal estimation errors weakened rPreSMA→rSTR connections and also modulated rAI→rSTR connections, causing the disruption of action update. Results provide information about the neurophysiological implementation of the so-called horse-race model of action control. We suggest that, contrary to what might be believed, unsuccessful action update could be a homeostatic process that represents a Bayes optimal encoding of uncertainty.

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.