Searching for bodies: ERP evidence for independent somatosensory processing during visual search for body-related information.

Attention allows us to select relevant information by modulating neural activity within sensory brain areas processing that information. Previous research has shown that visual perception of body stimuli recruits visual cortices together with observer's body representation in somatosensory cortex, which is known for processing body-related information (e.g., haptics, kinematics). However, whether attentional selection of visual body stimuli involves just visual or additional somatosensory areas remains elusive. Here we elicited visual and somatosensory evoked activity during a visual search task, whereby participants searched for target hand images defined by either visual (colour) or bodily (posture) features. In line with previous studies, we found electrophysiological evidence for attentional selection over visual areas (i.e., N2pc) regardless of the feature type. Importantly, after dissociating somatosensory from visual evoked activity, we show that only attentional selection of hand posture - but not hand colour - elicits modulation of somatosensory evoked electrocortical activity over somatosensory cortex. This suggests that attention may not only modulate cortical activity associated with the input-sensory modality (in this case, visual), but, depending on the type of attended information, it may also modulate cortical activity associated with another task-relevant sensory modality (in this case, somatosensory). Overall, our results provide evidence for a flexible attention mechanism that operates according to specific behavioural goals and the information embedded in the percept.

Persistent recruitment of somatosensory cortex during active maintenance of hand images in working memory.

Working memory (WM) supports temporary maintenance of task-relevant information. This process is associated with persistent activity in the sensory cortex processing the information (e.g., visual stimuli activate visual cortex). However, we argue here that more multifaceted stimuli moderate this sensory-locked activity and recruit distinctive cortices. Specifically, perception of bodies recruits somatosensory cortex (SCx) beyond early visual areas (suggesting embodiment processes). Here we explore persistent activation in processing areas beyond the sensory cortex initially relevant to the modality of the stimuli. Using visual and somatosensory evoked-potentials in a visual WM task, we isolated different levels of visual and somatosensory involvement during encoding of body and non-body-related images. Persistent activity increased in SCx only when maintaining body images in WM, whereas visual/posterior regions' activity increased significantly when maintaining non-body images. Our results bridge WM and embodiment frameworks, supporting a dynamic WM process where the nature of the information summons specific processing resources.

Extrastriate body area underlies aesthetic evaluation of body stimuli.

Humans appear to be the only animals to have developed the practice and culture of art. This practice presumably relies on special processing circuits within the human brain associated with a distinct subjective experience, termed aesthetic experience, and preferentially evoked by artistic stimuli. We assume that positive or negative aesthetic judgments are an important function of neuroaesthetic circuits. The localisation of these circuits in the brain remains unclear, though neuroimaging studies have suggested several possible neural correlates of aesthetic preference. We applied repetitive transcranial magnetic stimulation (rTMS) over candidate brain areas to disrupt aesthetic processing while healthy volunteers made aesthetic preference judgments between pairs of dance postures, or control non-body stimuli. Based on evidence from visual body perception studies, we targeted the ventral premotor cortex (vPMC) and extrastriate body area (EBA), in the left and right hemispheres. rTMS over EBA reduced aesthetic sensitivity for body stimuli relative to rTMS over vPMC, while no such difference was found for non-body stimuli. We interpret our results within the framework of dual routes for visual body processing. rTMS over either EBA or vPMC reduced the contributions of the stimulated area to body processing, leaving processing more reliant on the unaffected route. Disruption of EBA reduces the local processing of the stimuli and reduced observers' aesthetic sensitivity. Conversely, disruption of the global route via vPMC increased the relative contribution of the local route via EBA and thus increased aesthetic sensitivity. In this way, we suggest a complementary contribution of both local and global routes to aesthetic processing.

Towards a sensorimotor aesthetics of performing art.

The field of neuroaesthetics attempts to identify the brain processes underlying aesthetic experience, including but not limited to beauty. Previous neuroaesthetic studies have focussed largely on paintings and music, while performing arts such as dance have been less studied. Nevertheless, increasing knowledge of the neural mechanisms that represent the bodies and actions of others, and which contribute to empathy, make a neuroaesthetics of dance timely. Here, we present the first neuroscientific study of aesthetic perception in the context of the performing arts. We investigated brain areas whose activity during passive viewing of dance stimuli was related to later, independent aesthetic evaluation of the same stimuli. Brain activity of six naïve male subjects was measured using fMRI, while they watched 24 dance movements, and performed an irrelevant task. In a later session, participants rated each movement along a set of established aesthetic dimensions. The ratings were used to identify brain regions that were more active when viewing moves that received high average ratings than moves that received low average ratings. This contrast revealed bilateral activity in the occipital cortices and in right premotor cortex. Our results suggest a possible role of visual and sensorimotor brain areas in an automatic aesthetic response to dance. This sensorimotor response may explain why dance is widely appreciated in so many human cultures.

[Transcranial magnetic stimulation. Applications in cognitive neuroscience]. / Estimulación magnética transcraneal. Aplicaciones en neurociencia cognitiva.

OBJECTIVE: In this review we trace some of the mayor developments in the use of transcranial magnetic stimulation (TMS) as a technique for the investigation of cognitive neuroscience. Technical aspects of the magnetic stimulation are also reviewed. DEVELOPMENT: Among the many methods now available for studying activity of the human brain, magnetic stimulation is the only technique that allows us to interfere actively with human brain function. At the same time it provides a high degree of spatial and temporal resolution. Standard TMS applications (central motor conduction time, threshold and amplitude of motor evoked potentials) allow the evaluation of the motor conduction in the central nervous system and more complex TMS applications (paired pulse stimulation, silent period) permit study the mechanisms of diseases causing changes in the excitability of cortical areas. These techniques also allow investigation into motor disorder, epilepsy, cognitive function and psychiatric disorders. CONCLUSIONS: Transcranial magnetic stimulation applications have an important place among the investigative tools to study cognitive functions and neurological and psychiatric disorders. Even so, despite the many published research and clinical studies, a systematic study about the possible diagnostic value and role in neurocognitive rehabilitation of TMS testing need to be realized to offer new possibilities of future applications.

Action observation and acquired motor skills: an FMRI study with expert dancers.

When we observe someone performing an action, do our brains simulate making that action? Acquired motor skills offer a unique way to test this question, since people differ widely in the actions they have learned to perform. We used functional magnetic resonance imaging to study differences in brain activity between watching an action that one has learned to do and an action that one has not, in order to assess whether the brain processes of action observation are modulated by the expertise and motor repertoire of the observer. Experts in classical ballet, experts in capoeira and inexpert control subjects viewed videos of ballet or capoeira actions. Comparing the brain activity when dancers watched their own dance style versus the other style therefore reveals the influence of motor expertise on action observation. We found greater bilateral activations in premotor cortex and intraparietal sulcus, right superior parietal lobe and left posterior superior temporal sulcus when expert dancers viewed movements that they had been trained to perform compared to movements they had not. Our results show that this 'mirror system' integrates observed actions of others with an individual's personal motor repertoire, and suggest that the human brain understands actions by motor simulation.

Neuroarquitectura de la emoción musical / Neuroarchitecture of musical emotions

La respuesta emocional ante la música, o emoción musical, es una respuesta universal que depende de diferentes procesos psicológicos y recluta una extensa red de estructuras neuronales. Mediante el empleo de técnicas como la electroencefalografía, la resonancia magnética funcional y los estudios con población clínica e individuos con formación musical previa, se ha empezado a dilucidar estos mecanismos cerebrales. El objetivo de este artículo es hacer una revisión de los trabajos más relevantes en los que se identifican los correlatos neuronales de la emoción musical, desde los procesos más automáticos hasta los más complejos, y comprender cómo interaccionan en el cerebro. En concreto, se describe cómo la presentación de música emocional está asociada a una respuesta rápida en estructuras talámicas y subtalámicas, acompañada por cambios electrodérmicos y endocrinos. También se explica que el procesamiento de la emoción musical implica la activación de la corteza auditiva y estructuras límbicas y paralímbicas, como la amígdala, la corteza cinguladaanterior o el hipocampo, lo que demuestra la contribución del sistema límbico a la emoción musical. Asimismo, se detalla cómo la emoción musical depende de los significados semántico y sintáctico de la música, procesados en áreas temporales y parietofrontales, respectivamente. Además, se mencionan trabajos recientes que han demostrado cómo los mecanismos de simulación emocional también contribuyen a la emoción musical. Por último, se hace un resumen de estos trabajos, comentando sus limitaciones y ofreciendo alternativas para seguir avanzando en el estudio de la neuroarquitectura de la emoción musical (AU)

The emotional response to music, or musical emotion, is a universal response that draws on diverse psychological processes implemented in a large array of neural structures and mechanisms. Studies using electroencephalography, functional magnetic resonance, lesions and individuals with extent musical training have begun to elucidate some of these mechanisms. The objective of this article is reviewing the most relevant studies that have tried to identify the neural correlates of musical emotion from the more automatic to the more complex processes, and to understand how these correlates interact in the brain. The article describes how the presentation of music perceived as emotional is associated with a rapid autonomic response in thalamic and subthalamic structures, accompanied by changes in the electrodermal and endocrine responses. It also explains how musical emotion processing activates auditory cortex, as well as a series of limbic and paralimbic structures, such as the amygdala, the anterior cingulate cortex or the hippocampus, demonstrating the relevant contribution of the limbic system to musical emotion. Further, it is detailed how musical emotion depends to a great extent on semantic and syntactic process carried out in temporal and parietofrontal areas, respectively. Some of the recent works demonstrating that musical emotion highly relies on emotional simulation are also mentioned. Finally, a summary of these studies, their limitations, and suggestions for further research on the neuroarchitecture of musical emotion are given (AU)

Estimulación magnética transcraneal. Aplicaciones en neurociencia cognitiva / Transcranial magnetic stimulation. Applications in cognitive neuroscience

Objetivo. El objetivo de este trabajo es describir los nuevos usos de la estimulación magnética transcraneal (EMT) en la investigación neurocognitiva básica. Se revisan también distintos aspectos técnicos de la EMT. Desarrollo. A diferencia de los distintos instrumentos utilizados en neuroimagen para la investigación de la actividad cerebral, la EMT permite estudiar el funcionamiento cerebral produciendo una interferencia en su actividad normal. Además, proporciona una alta resolución temporal y espacial. Se han utilizado habitualmente sencillas aplicaciones de la EMT (velocidad de conducción, umbral y amplitud de potenciales evocados motores) para el estudio del sistema motor. Estos estudios, así como el desarrollo de nuevas aplicaciones más complejas de la EMT (estímulos magnéticos apareados, período de silencio) y EMT repetitiva, han permitido la investigación, bajo este paradigma, de trastornos motores y psiquiátricos y de la función cognitiva. Conclusiones. El conjunto de las distintas aplicaciones de la EMT la sitúa dentro de los instrumentos importantes para el estudio de la función cognitiva, los trastornos neurológicos y las alteraciones psiquiátricas. A pesar de la gran cantidad de investigaciones que en la actualidad optan por el uso de la EMT, se requiere un estudio sistemático sobre su valor en la clínica (diagnóstico, pronóstico y posible papel en la rehabilitación), ofreciendo un amplio abanico de posibilidades para futuras aplicaciones (AU)

Objective. In this review we trace some of the mayor developments in the use of transcranial magnetic stimulation (TMS) as a technique for the investigation of cognitive neuroscience. Technical aspects of the magnetic stimulation are also reviewed. Development. Among the many methods now available for studying activity of the human brain, magnetic stimulation is the only technique that allows us to interfere actively with human brain function. At the same time it provides a high degree of spatial and temporal resolution. Standard TMS applications (central motor conduction time, threshold and amplitude of motor evoked potentials) allow the evaluation of the motor conduction in the central nervous system and more complex TMS applications (paired-pulse stimulation, silent period) permit study the mechanisms of diseases causing changes in the excitability of cortical areas. These techniques also allow investigation into motor disorder, epilepsy, cognitive function and psychiatric disorders. Conclusions. Transcranial magnetic stimulation applications have an important place among the investigative tools to study cognitive functions and neurological and psychiatric disorders. Even so, despite the many published research and clinical studies, a systematic study about the possible diagnostic value and role in neurocognitive rehabilitation of TMS testing need to be realized to offer new possibilities of future applications (AU)